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diff --git a/share/info/gccint.info b/share/info/gccint.info new file mode 100644 index 0000000..ac9b051 --- /dev/null +++ b/share/info/gccint.info @@ -0,0 +1,47869 @@ +This is doc/gccint.info, produced by makeinfo version 4.13 from +/Volumes/androidtc/androidtoolchain/./src/build/../gcc/gcc-4.6/gcc/doc/gccint.texi. + +Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010 Free +Software Foundation, Inc. + + Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Funding Free Software", the Front-Cover Texts +being (a) (see below), and with the Back-Cover Texts being (b) (see +below). A copy of the license is included in the section entitled "GNU +Free Documentation License". + + (a) The FSF's Front-Cover Text is: + + A GNU Manual + + (b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU +software. Copies published by the Free Software Foundation raise +funds for GNU development. + +INFO-DIR-SECTION Software development +START-INFO-DIR-ENTRY +* gccint: (gccint). Internals of the GNU Compiler Collection. +END-INFO-DIR-ENTRY + This file documents the internals of the GNU compilers. + + Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, +1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010 Free +Software Foundation, Inc. + + Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Funding Free Software", the Front-Cover Texts +being (a) (see below), and with the Back-Cover Texts being (b) (see +below). A copy of the license is included in the section entitled "GNU +Free Documentation License". + + (a) The FSF's Front-Cover Text is: + + A GNU Manual + + (b) The FSF's Back-Cover Text is: + + You have freedom to copy and modify this GNU Manual, like GNU +software. Copies published by the Free Software Foundation raise +funds for GNU development. + + + +File: gccint.info, Node: Top, Next: Contributing, Up: (DIR) + +Introduction +************ + +This manual documents the internals of the GNU compilers, including how +to port them to new targets and some information about how to write +front ends for new languages. It corresponds to the compilers +(GCC) version 4.6.x-google. The use of the GNU compilers is documented +in a separate manual. *Note Introduction: (gcc)Top. + + This manual is mainly a reference manual rather than a tutorial. It +discusses how to contribute to GCC (*note Contributing::), the +characteristics of the machines supported by GCC as hosts and targets +(*note Portability::), how GCC relates to the ABIs on such systems +(*note Interface::), and the characteristics of the languages for which +GCC front ends are written (*note Languages::). It then describes the +GCC source tree structure and build system, some of the interfaces to +GCC front ends, and how support for a target system is implemented in +GCC. + + Additional tutorial information is linked to from +`http://gcc.gnu.org/readings.html'. + +* Menu: + +* Contributing:: How to contribute to testing and developing GCC. +* Portability:: Goals of GCC's portability features. +* Interface:: Function-call interface of GCC output. +* Libgcc:: Low-level runtime library used by GCC. +* Languages:: Languages for which GCC front ends are written. +* Source Tree:: GCC source tree structure and build system. +* Testsuites:: GCC testsuites. +* Options:: Option specification files. +* Passes:: Order of passes, what they do, and what each file is for. +* GENERIC:: Language-independent representation generated by Front Ends +* GIMPLE:: Tuple representation used by Tree SSA optimizers +* Tree SSA:: Analysis and optimization of GIMPLE +* RTL:: Machine-dependent low-level intermediate representation. +* Control Flow:: Maintaining and manipulating the control flow graph. +* Loop Analysis and Representation:: Analysis and representation of loops +* Machine Desc:: How to write machine description instruction patterns. +* Target Macros:: How to write the machine description C macros and functions. +* Host Config:: Writing the `xm-MACHINE.h' file. +* Fragments:: Writing the `t-TARGET' and `x-HOST' files. +* Collect2:: How `collect2' works; how it finds `ld'. +* Header Dirs:: Understanding the standard header file directories. +* Type Information:: GCC's memory management; generating type information. +* Plugins:: Extending the compiler with plugins. +* LTO:: Using Link-Time Optimization. + +* Funding:: How to help assure funding for free software. +* GNU Project:: The GNU Project and GNU/Linux. + +* Copying:: GNU General Public License says + how you can copy and share GCC. +* GNU Free Documentation License:: How you can copy and share this manual. +* Contributors:: People who have contributed to GCC. + +* Option Index:: Index to command line options. +* Concept Index:: Index of concepts and symbol names. + + +File: gccint.info, Node: Contributing, Next: Portability, Prev: Top, Up: Top + +1 Contributing to GCC Development +********************************* + +If you would like to help pretest GCC releases to assure they work well, +current development sources are available by SVN (see +`http://gcc.gnu.org/svn.html'). Source and binary snapshots are also +available for FTP; see `http://gcc.gnu.org/snapshots.html'. + + If you would like to work on improvements to GCC, please read the +advice at these URLs: + + `http://gcc.gnu.org/contribute.html' + `http://gcc.gnu.org/contributewhy.html' + +for information on how to make useful contributions and avoid +duplication of effort. Suggested projects are listed at +`http://gcc.gnu.org/projects/'. + + +File: gccint.info, Node: Portability, Next: Interface, Prev: Contributing, Up: Top + +2 GCC and Portability +********************* + +GCC itself aims to be portable to any machine where `int' is at least a +32-bit type. It aims to target machines with a flat (non-segmented) +byte addressed data address space (the code address space can be +separate). Target ABIs may have 8, 16, 32 or 64-bit `int' type. `char' +can be wider than 8 bits. + + GCC gets most of the information about the target machine from a +machine description which gives an algebraic formula for each of the +machine's instructions. This is a very clean way to describe the +target. But when the compiler needs information that is difficult to +express in this fashion, ad-hoc parameters have been defined for +machine descriptions. The purpose of portability is to reduce the +total work needed on the compiler; it was not of interest for its own +sake. + + GCC does not contain machine dependent code, but it does contain code +that depends on machine parameters such as endianness (whether the most +significant byte has the highest or lowest address of the bytes in a +word) and the availability of autoincrement addressing. In the +RTL-generation pass, it is often necessary to have multiple strategies +for generating code for a particular kind of syntax tree, strategies +that are usable for different combinations of parameters. Often, not +all possible cases have been addressed, but only the common ones or +only the ones that have been encountered. As a result, a new target +may require additional strategies. You will know if this happens +because the compiler will call `abort'. Fortunately, the new +strategies can be added in a machine-independent fashion, and will +affect only the target machines that need them. + + +File: gccint.info, Node: Interface, Next: Libgcc, Prev: Portability, Up: Top + +3 Interfacing to GCC Output +*************************** + +GCC is normally configured to use the same function calling convention +normally in use on the target system. This is done with the +machine-description macros described (*note Target Macros::). + + However, returning of structure and union values is done differently on +some target machines. As a result, functions compiled with PCC +returning such types cannot be called from code compiled with GCC, and +vice versa. This does not cause trouble often because few Unix library +routines return structures or unions. + + GCC code returns structures and unions that are 1, 2, 4 or 8 bytes +long in the same registers used for `int' or `double' return values. +(GCC typically allocates variables of such types in registers also.) +Structures and unions of other sizes are returned by storing them into +an address passed by the caller (usually in a register). The target +hook `TARGET_STRUCT_VALUE_RTX' tells GCC where to pass this address. + + By contrast, PCC on most target machines returns structures and unions +of any size by copying the data into an area of static storage, and then +returning the address of that storage as if it were a pointer value. +The caller must copy the data from that memory area to the place where +the value is wanted. This is slower than the method used by GCC, and +fails to be reentrant. + + On some target machines, such as RISC machines and the 80386, the +standard system convention is to pass to the subroutine the address of +where to return the value. On these machines, GCC has been configured +to be compatible with the standard compiler, when this method is used. +It may not be compatible for structures of 1, 2, 4 or 8 bytes. + + GCC uses the system's standard convention for passing arguments. On +some machines, the first few arguments are passed in registers; in +others, all are passed on the stack. It would be possible to use +registers for argument passing on any machine, and this would probably +result in a significant speedup. But the result would be complete +incompatibility with code that follows the standard convention. So this +change is practical only if you are switching to GCC as the sole C +compiler for the system. We may implement register argument passing on +certain machines once we have a complete GNU system so that we can +compile the libraries with GCC. + + On some machines (particularly the SPARC), certain types of arguments +are passed "by invisible reference". This means that the value is +stored in memory, and the address of the memory location is passed to +the subroutine. + + If you use `longjmp', beware of automatic variables. ISO C says that +automatic variables that are not declared `volatile' have undefined +values after a `longjmp'. And this is all GCC promises to do, because +it is very difficult to restore register variables correctly, and one +of GCC's features is that it can put variables in registers without +your asking it to. + + +File: gccint.info, Node: Libgcc, Next: Languages, Prev: Interface, Up: Top + +4 The GCC low-level runtime library +*********************************** + +GCC provides a low-level runtime library, `libgcc.a' or `libgcc_s.so.1' +on some platforms. GCC generates calls to routines in this library +automatically, whenever it needs to perform some operation that is too +complicated to emit inline code for. + + Most of the routines in `libgcc' handle arithmetic operations that the +target processor cannot perform directly. This includes integer +multiply and divide on some machines, and all floating-point and +fixed-point operations on other machines. `libgcc' also includes +routines for exception handling, and a handful of miscellaneous +operations. + + Some of these routines can be defined in mostly machine-independent C. +Others must be hand-written in assembly language for each processor +that needs them. + + GCC will also generate calls to C library routines, such as `memcpy' +and `memset', in some cases. The set of routines that GCC may possibly +use is documented in *note Other Builtins: (gcc)Other Builtins. + + These routines take arguments and return values of a specific machine +mode, not a specific C type. *Note Machine Modes::, for an explanation +of this concept. For illustrative purposes, in this chapter the +floating point type `float' is assumed to correspond to `SFmode'; +`double' to `DFmode'; and `long double' to both `TFmode' and `XFmode'. +Similarly, the integer types `int' and `unsigned int' correspond to +`SImode'; `long' and `unsigned long' to `DImode'; and `long long' and +`unsigned long long' to `TImode'. + +* Menu: + +* Integer library routines:: +* Soft float library routines:: +* Decimal float library routines:: +* Fixed-point fractional library routines:: +* Exception handling routines:: +* Miscellaneous routines:: + + +File: gccint.info, Node: Integer library routines, Next: Soft float library routines, Up: Libgcc + +4.1 Routines for integer arithmetic +=================================== + +The integer arithmetic routines are used on platforms that don't provide +hardware support for arithmetic operations on some modes. + +4.1.1 Arithmetic functions +-------------------------- + + -- Runtime Function: int __ashlsi3 (int A, int B) + -- Runtime Function: long __ashldi3 (long A, int B) + -- Runtime Function: long long __ashlti3 (long long A, int B) + These functions return the result of shifting A left by B bits. + + -- Runtime Function: int __ashrsi3 (int A, int B) + -- Runtime Function: long __ashrdi3 (long A, int B) + -- Runtime Function: long long __ashrti3 (long long A, int B) + These functions return the result of arithmetically shifting A + right by B bits. + + -- Runtime Function: int __divsi3 (int A, int B) + -- Runtime Function: long __divdi3 (long A, long B) + -- Runtime Function: long long __divti3 (long long A, long long B) + These functions return the quotient of the signed division of A and + B. + + -- Runtime Function: int __lshrsi3 (int A, int B) + -- Runtime Function: long __lshrdi3 (long A, int B) + -- Runtime Function: long long __lshrti3 (long long A, int B) + These functions return the result of logically shifting A right by + B bits. + + -- Runtime Function: int __modsi3 (int A, int B) + -- Runtime Function: long __moddi3 (long A, long B) + -- Runtime Function: long long __modti3 (long long A, long long B) + These functions return the remainder of the signed division of A + and B. + + -- Runtime Function: int __mulsi3 (int A, int B) + -- Runtime Function: long __muldi3 (long A, long B) + -- Runtime Function: long long __multi3 (long long A, long long B) + These functions return the product of A and B. + + -- Runtime Function: long __negdi2 (long A) + -- Runtime Function: long long __negti2 (long long A) + These functions return the negation of A. + + -- Runtime Function: unsigned int __udivsi3 (unsigned int A, unsigned + int B) + -- Runtime Function: unsigned long __udivdi3 (unsigned long A, + unsigned long B) + -- Runtime Function: unsigned long long __udivti3 (unsigned long long + A, unsigned long long B) + These functions return the quotient of the unsigned division of A + and B. + + -- Runtime Function: unsigned long __udivmoddi3 (unsigned long A, + unsigned long B, unsigned long *C) + -- Runtime Function: unsigned long long __udivti3 (unsigned long long + A, unsigned long long B, unsigned long long *C) + These functions calculate both the quotient and remainder of the + unsigned division of A and B. The return value is the quotient, + and the remainder is placed in variable pointed to by C. + + -- Runtime Function: unsigned int __umodsi3 (unsigned int A, unsigned + int B) + -- Runtime Function: unsigned long __umoddi3 (unsigned long A, + unsigned long B) + -- Runtime Function: unsigned long long __umodti3 (unsigned long long + A, unsigned long long B) + These functions return the remainder of the unsigned division of A + and B. + +4.1.2 Comparison functions +-------------------------- + +The following functions implement integral comparisons. These functions +implement a low-level compare, upon which the higher level comparison +operators (such as less than and greater than or equal to) can be +constructed. The returned values lie in the range zero to two, to allow +the high-level operators to be implemented by testing the returned +result using either signed or unsigned comparison. + + -- Runtime Function: int __cmpdi2 (long A, long B) + -- Runtime Function: int __cmpti2 (long long A, long long B) + These functions perform a signed comparison of A and B. If A is + less than B, they return 0; if A is greater than B, they return 2; + and if A and B are equal they return 1. + + -- Runtime Function: int __ucmpdi2 (unsigned long A, unsigned long B) + -- Runtime Function: int __ucmpti2 (unsigned long long A, unsigned + long long B) + These functions perform an unsigned comparison of A and B. If A + is less than B, they return 0; if A is greater than B, they return + 2; and if A and B are equal they return 1. + +4.1.3 Trapping arithmetic functions +----------------------------------- + +The following functions implement trapping arithmetic. These functions +call the libc function `abort' upon signed arithmetic overflow. + + -- Runtime Function: int __absvsi2 (int A) + -- Runtime Function: long __absvdi2 (long A) + These functions return the absolute value of A. + + -- Runtime Function: int __addvsi3 (int A, int B) + -- Runtime Function: long __addvdi3 (long A, long B) + These functions return the sum of A and B; that is `A + B'. + + -- Runtime Function: int __mulvsi3 (int A, int B) + -- Runtime Function: long __mulvdi3 (long A, long B) + The functions return the product of A and B; that is `A * B'. + + -- Runtime Function: int __negvsi2 (int A) + -- Runtime Function: long __negvdi2 (long A) + These functions return the negation of A; that is `-A'. + + -- Runtime Function: int __subvsi3 (int A, int B) + -- Runtime Function: long __subvdi3 (long A, long B) + These functions return the difference between B and A; that is `A + - B'. + +4.1.4 Bit operations +-------------------- + + -- Runtime Function: int __clzsi2 (int A) + -- Runtime Function: int __clzdi2 (long A) + -- Runtime Function: int __clzti2 (long long A) + These functions return the number of leading 0-bits in A, starting + at the most significant bit position. If A is zero, the result is + undefined. + + -- Runtime Function: int __ctzsi2 (int A) + -- Runtime Function: int __ctzdi2 (long A) + -- Runtime Function: int __ctzti2 (long long A) + These functions return the number of trailing 0-bits in A, starting + at the least significant bit position. If A is zero, the result is + undefined. + + -- Runtime Function: int __ffsdi2 (long A) + -- Runtime Function: int __ffsti2 (long long A) + These functions return the index of the least significant 1-bit in + A, or the value zero if A is zero. The least significant bit is + index one. + + -- Runtime Function: int __paritysi2 (int A) + -- Runtime Function: int __paritydi2 (long A) + -- Runtime Function: int __parityti2 (long long A) + These functions return the value zero if the number of bits set in + A is even, and the value one otherwise. + + -- Runtime Function: int __popcountsi2 (int A) + -- Runtime Function: int __popcountdi2 (long A) + -- Runtime Function: int __popcountti2 (long long A) + These functions return the number of bits set in A. + + -- Runtime Function: int32_t __bswapsi2 (int32_t A) + -- Runtime Function: int64_t __bswapdi2 (int64_t A) + These functions return the A byteswapped. + + +File: gccint.info, Node: Soft float library routines, Next: Decimal float library routines, Prev: Integer library routines, Up: Libgcc + +4.2 Routines for floating point emulation +========================================= + +The software floating point library is used on machines which do not +have hardware support for floating point. It is also used whenever +`-msoft-float' is used to disable generation of floating point +instructions. (Not all targets support this switch.) + + For compatibility with other compilers, the floating point emulation +routines can be renamed with the `DECLARE_LIBRARY_RENAMES' macro (*note +Library Calls::). In this section, the default names are used. + + Presently the library does not support `XFmode', which is used for +`long double' on some architectures. + +4.2.1 Arithmetic functions +-------------------------- + + -- Runtime Function: float __addsf3 (float A, float B) + -- Runtime Function: double __adddf3 (double A, double B) + -- Runtime Function: long double __addtf3 (long double A, long double + B) + -- Runtime Function: long double __addxf3 (long double A, long double + B) + These functions return the sum of A and B. + + -- Runtime Function: float __subsf3 (float A, float B) + -- Runtime Function: double __subdf3 (double A, double B) + -- Runtime Function: long double __subtf3 (long double A, long double + B) + -- Runtime Function: long double __subxf3 (long double A, long double + B) + These functions return the difference between B and A; that is, + A - B. + + -- Runtime Function: float __mulsf3 (float A, float B) + -- Runtime Function: double __muldf3 (double A, double B) + -- Runtime Function: long double __multf3 (long double A, long double + B) + -- Runtime Function: long double __mulxf3 (long double A, long double + B) + These functions return the product of A and B. + + -- Runtime Function: float __divsf3 (float A, float B) + -- Runtime Function: double __divdf3 (double A, double B) + -- Runtime Function: long double __divtf3 (long double A, long double + B) + -- Runtime Function: long double __divxf3 (long double A, long double + B) + These functions return the quotient of A and B; that is, A / B. + + -- Runtime Function: float __negsf2 (float A) + -- Runtime Function: double __negdf2 (double A) + -- Runtime Function: long double __negtf2 (long double A) + -- Runtime Function: long double __negxf2 (long double A) + These functions return the negation of A. They simply flip the + sign bit, so they can produce negative zero and negative NaN. + +4.2.2 Conversion functions +-------------------------- + + -- Runtime Function: double __extendsfdf2 (float A) + -- Runtime Function: long double __extendsftf2 (float A) + -- Runtime Function: long double __extendsfxf2 (float A) + -- Runtime Function: long double __extenddftf2 (double A) + -- Runtime Function: long double __extenddfxf2 (double A) + These functions extend A to the wider mode of their return type. + + -- Runtime Function: double __truncxfdf2 (long double A) + -- Runtime Function: double __trunctfdf2 (long double A) + -- Runtime Function: float __truncxfsf2 (long double A) + -- Runtime Function: float __trunctfsf2 (long double A) + -- Runtime Function: float __truncdfsf2 (double A) + These functions truncate A to the narrower mode of their return + type, rounding toward zero. + + -- Runtime Function: int __fixsfsi (float A) + -- Runtime Function: int __fixdfsi (double A) + -- Runtime Function: int __fixtfsi (long double A) + -- Runtime Function: int __fixxfsi (long double A) + These functions convert A to a signed integer, rounding toward + zero. + + -- Runtime Function: long __fixsfdi (float A) + -- Runtime Function: long __fixdfdi (double A) + -- Runtime Function: long __fixtfdi (long double A) + -- Runtime Function: long __fixxfdi (long double A) + These functions convert A to a signed long, rounding toward zero. + + -- Runtime Function: long long __fixsfti (float A) + -- Runtime Function: long long __fixdfti (double A) + -- Runtime Function: long long __fixtfti (long double A) + -- Runtime Function: long long __fixxfti (long double A) + These functions convert A to a signed long long, rounding toward + zero. + + -- Runtime Function: unsigned int __fixunssfsi (float A) + -- Runtime Function: unsigned int __fixunsdfsi (double A) + -- Runtime Function: unsigned int __fixunstfsi (long double A) + -- Runtime Function: unsigned int __fixunsxfsi (long double A) + These functions convert A to an unsigned integer, rounding toward + zero. Negative values all become zero. + + -- Runtime Function: unsigned long __fixunssfdi (float A) + -- Runtime Function: unsigned long __fixunsdfdi (double A) + -- Runtime Function: unsigned long __fixunstfdi (long double A) + -- Runtime Function: unsigned long __fixunsxfdi (long double A) + These functions convert A to an unsigned long, rounding toward + zero. Negative values all become zero. + + -- Runtime Function: unsigned long long __fixunssfti (float A) + -- Runtime Function: unsigned long long __fixunsdfti (double A) + -- Runtime Function: unsigned long long __fixunstfti (long double A) + -- Runtime Function: unsigned long long __fixunsxfti (long double A) + These functions convert A to an unsigned long long, rounding + toward zero. Negative values all become zero. + + -- Runtime Function: float __floatsisf (int I) + -- Runtime Function: double __floatsidf (int I) + -- Runtime Function: long double __floatsitf (int I) + -- Runtime Function: long double __floatsixf (int I) + These functions convert I, a signed integer, to floating point. + + -- Runtime Function: float __floatdisf (long I) + -- Runtime Function: double __floatdidf (long I) + -- Runtime Function: long double __floatditf (long I) + -- Runtime Function: long double __floatdixf (long I) + These functions convert I, a signed long, to floating point. + + -- Runtime Function: float __floattisf (long long I) + -- Runtime Function: double __floattidf (long long I) + -- Runtime Function: long double __floattitf (long long I) + -- Runtime Function: long double __floattixf (long long I) + These functions convert I, a signed long long, to floating point. + + -- Runtime Function: float __floatunsisf (unsigned int I) + -- Runtime Function: double __floatunsidf (unsigned int I) + -- Runtime Function: long double __floatunsitf (unsigned int I) + -- Runtime Function: long double __floatunsixf (unsigned int I) + These functions convert I, an unsigned integer, to floating point. + + -- Runtime Function: float __floatundisf (unsigned long I) + -- Runtime Function: double __floatundidf (unsigned long I) + -- Runtime Function: long double __floatunditf (unsigned long I) + -- Runtime Function: long double __floatundixf (unsigned long I) + These functions convert I, an unsigned long, to floating point. + + -- Runtime Function: float __floatuntisf (unsigned long long I) + -- Runtime Function: double __floatuntidf (unsigned long long I) + -- Runtime Function: long double __floatuntitf (unsigned long long I) + -- Runtime Function: long double __floatuntixf (unsigned long long I) + These functions convert I, an unsigned long long, to floating + point. + +4.2.3 Comparison functions +-------------------------- + +There are two sets of basic comparison functions. + + -- Runtime Function: int __cmpsf2 (float A, float B) + -- Runtime Function: int __cmpdf2 (double A, double B) + -- Runtime Function: int __cmptf2 (long double A, long double B) + These functions calculate a <=> b. That is, if A is less than B, + they return -1; if A is greater than B, they return 1; and if A + and B are equal they return 0. If either argument is NaN they + return 1, but you should not rely on this; if NaN is a + possibility, use one of the higher-level comparison functions. + + -- Runtime Function: int __unordsf2 (float A, float B) + -- Runtime Function: int __unorddf2 (double A, double B) + -- Runtime Function: int __unordtf2 (long double A, long double B) + These functions return a nonzero value if either argument is NaN, + otherwise 0. + + There is also a complete group of higher level functions which +correspond directly to comparison operators. They implement the ISO C +semantics for floating-point comparisons, taking NaN into account. Pay +careful attention to the return values defined for each set. Under the +hood, all of these routines are implemented as + + if (__unordXf2 (a, b)) + return E; + return __cmpXf2 (a, b); + +where E is a constant chosen to give the proper behavior for NaN. +Thus, the meaning of the return value is different for each set. Do +not rely on this implementation; only the semantics documented below +are guaranteed. + + -- Runtime Function: int __eqsf2 (float A, float B) + -- Runtime Function: int __eqdf2 (double A, double B) + -- Runtime Function: int __eqtf2 (long double A, long double B) + These functions return zero if neither argument is NaN, and A and + B are equal. + + -- Runtime Function: int __nesf2 (float A, float B) + -- Runtime Function: int __nedf2 (double A, double B) + -- Runtime Function: int __netf2 (long double A, long double B) + These functions return a nonzero value if either argument is NaN, + or if A and B are unequal. + + -- Runtime Function: int __gesf2 (float A, float B) + -- Runtime Function: int __gedf2 (double A, double B) + -- Runtime Function: int __getf2 (long double A, long double B) + These functions return a value greater than or equal to zero if + neither argument is NaN, and A is greater than or equal to B. + + -- Runtime Function: int __ltsf2 (float A, float B) + -- Runtime Function: int __ltdf2 (double A, double B) + -- Runtime Function: int __lttf2 (long double A, long double B) + These functions return a value less than zero if neither argument + is NaN, and A is strictly less than B. + + -- Runtime Function: int __lesf2 (float A, float B) + -- Runtime Function: int __ledf2 (double A, double B) + -- Runtime Function: int __letf2 (long double A, long double B) + These functions return a value less than or equal to zero if + neither argument is NaN, and A is less than or equal to B. + + -- Runtime Function: int __gtsf2 (float A, float B) + -- Runtime Function: int __gtdf2 (double A, double B) + -- Runtime Function: int __gttf2 (long double A, long double B) + These functions return a value greater than zero if neither + argument is NaN, and A is strictly greater than B. + +4.2.4 Other floating-point functions +------------------------------------ + + -- Runtime Function: float __powisf2 (float A, int B) + -- Runtime Function: double __powidf2 (double A, int B) + -- Runtime Function: long double __powitf2 (long double A, int B) + -- Runtime Function: long double __powixf2 (long double A, int B) + These functions convert raise A to the power B. + + -- Runtime Function: complex float __mulsc3 (float A, float B, float + C, float D) + -- Runtime Function: complex double __muldc3 (double A, double B, + double C, double D) + -- Runtime Function: complex long double __multc3 (long double A, long + double B, long double C, long double D) + -- Runtime Function: complex long double __mulxc3 (long double A, long + double B, long double C, long double D) + These functions return the product of A + iB and C + iD, following + the rules of C99 Annex G. + + -- Runtime Function: complex float __divsc3 (float A, float B, float + C, float D) + -- Runtime Function: complex double __divdc3 (double A, double B, + double C, double D) + -- Runtime Function: complex long double __divtc3 (long double A, long + double B, long double C, long double D) + -- Runtime Function: complex long double __divxc3 (long double A, long + double B, long double C, long double D) + These functions return the quotient of A + iB and C + iD (i.e., (A + + iB) / (C + iD)), following the rules of C99 Annex G. + + +File: gccint.info, Node: Decimal float library routines, Next: Fixed-point fractional library routines, Prev: Soft float library routines, Up: Libgcc + +4.3 Routines for decimal floating point emulation +================================================= + +The software decimal floating point library implements IEEE 754-2008 +decimal floating point arithmetic and is only activated on selected +targets. + + The software decimal floating point library supports either DPD +(Densely Packed Decimal) or BID (Binary Integer Decimal) encoding as +selected at configure time. + +4.3.1 Arithmetic functions +-------------------------- + + -- Runtime Function: _Decimal32 __dpd_addsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal32 __bid_addsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal64 __dpd_adddd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal64 __bid_adddd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal128 __dpd_addtd3 (_Decimal128 A, + _Decimal128 B) + -- Runtime Function: _Decimal128 __bid_addtd3 (_Decimal128 A, + _Decimal128 B) + These functions return the sum of A and B. + + -- Runtime Function: _Decimal32 __dpd_subsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal32 __bid_subsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal64 __dpd_subdd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal64 __bid_subdd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal128 __dpd_subtd3 (_Decimal128 A, + _Decimal128 B) + -- Runtime Function: _Decimal128 __bid_subtd3 (_Decimal128 A, + _Decimal128 B) + These functions return the difference between B and A; that is, + A - B. + + -- Runtime Function: _Decimal32 __dpd_mulsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal32 __bid_mulsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal64 __dpd_muldd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal64 __bid_muldd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal128 __dpd_multd3 (_Decimal128 A, + _Decimal128 B) + -- Runtime Function: _Decimal128 __bid_multd3 (_Decimal128 A, + _Decimal128 B) + These functions return the product of A and B. + + -- Runtime Function: _Decimal32 __dpd_divsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal32 __bid_divsd3 (_Decimal32 A, _Decimal32 + B) + -- Runtime Function: _Decimal64 __dpd_divdd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal64 __bid_divdd3 (_Decimal64 A, _Decimal64 + B) + -- Runtime Function: _Decimal128 __dpd_divtd3 (_Decimal128 A, + _Decimal128 B) + -- Runtime Function: _Decimal128 __bid_divtd3 (_Decimal128 A, + _Decimal128 B) + These functions return the quotient of A and B; that is, A / B. + + -- Runtime Function: _Decimal32 __dpd_negsd2 (_Decimal32 A) + -- Runtime Function: _Decimal32 __bid_negsd2 (_Decimal32 A) + -- Runtime Function: _Decimal64 __dpd_negdd2 (_Decimal64 A) + -- Runtime Function: _Decimal64 __bid_negdd2 (_Decimal64 A) + -- Runtime Function: _Decimal128 __dpd_negtd2 (_Decimal128 A) + -- Runtime Function: _Decimal128 __bid_negtd2 (_Decimal128 A) + These functions return the negation of A. They simply flip the + sign bit, so they can produce negative zero and negative NaN. + +4.3.2 Conversion functions +-------------------------- + + -- Runtime Function: _Decimal64 __dpd_extendsddd2 (_Decimal32 A) + -- Runtime Function: _Decimal64 __bid_extendsddd2 (_Decimal32 A) + -- Runtime Function: _Decimal128 __dpd_extendsdtd2 (_Decimal32 A) + -- Runtime Function: _Decimal128 __bid_extendsdtd2 (_Decimal32 A) + -- Runtime Function: _Decimal128 __dpd_extendddtd2 (_Decimal64 A) + -- Runtime Function: _Decimal128 __bid_extendddtd2 (_Decimal64 A) + -- Runtime Function: _Decimal32 __dpd_truncddsd2 (_Decimal64 A) + -- Runtime Function: _Decimal32 __bid_truncddsd2 (_Decimal64 A) + -- Runtime Function: _Decimal32 __dpd_trunctdsd2 (_Decimal128 A) + -- Runtime Function: _Decimal32 __bid_trunctdsd2 (_Decimal128 A) + -- Runtime Function: _Decimal64 __dpd_trunctddd2 (_Decimal128 A) + -- Runtime Function: _Decimal64 __bid_trunctddd2 (_Decimal128 A) + These functions convert the value A from one decimal floating type + to another. + + -- Runtime Function: _Decimal64 __dpd_extendsfdd (float A) + -- Runtime Function: _Decimal64 __bid_extendsfdd (float A) + -- Runtime Function: _Decimal128 __dpd_extendsftd (float A) + -- Runtime Function: _Decimal128 __bid_extendsftd (float A) + -- Runtime Function: _Decimal128 __dpd_extenddftd (double A) + -- Runtime Function: _Decimal128 __bid_extenddftd (double A) + -- Runtime Function: _Decimal128 __dpd_extendxftd (long double A) + -- Runtime Function: _Decimal128 __bid_extendxftd (long double A) + -- Runtime Function: _Decimal32 __dpd_truncdfsd (double A) + -- Runtime Function: _Decimal32 __bid_truncdfsd (double A) + -- Runtime Function: _Decimal32 __dpd_truncxfsd (long double A) + -- Runtime Function: _Decimal32 __bid_truncxfsd (long double A) + -- Runtime Function: _Decimal32 __dpd_trunctfsd (long double A) + -- Runtime Function: _Decimal32 __bid_trunctfsd (long double A) + -- Runtime Function: _Decimal64 __dpd_truncxfdd (long double A) + -- Runtime Function: _Decimal64 __bid_truncxfdd (long double A) + -- Runtime Function: _Decimal64 __dpd_trunctfdd (long double A) + -- Runtime Function: _Decimal64 __bid_trunctfdd (long double A) + These functions convert the value of A from a binary floating type + to a decimal floating type of a different size. + + -- Runtime Function: float __dpd_truncddsf (_Decimal64 A) + -- Runtime Function: float __bid_truncddsf (_Decimal64 A) + -- Runtime Function: float __dpd_trunctdsf (_Decimal128 A) + -- Runtime Function: float __bid_trunctdsf (_Decimal128 A) + -- Runtime Function: double __dpd_extendsddf (_Decimal32 A) + -- Runtime Function: double __bid_extendsddf (_Decimal32 A) + -- Runtime Function: double __dpd_trunctddf (_Decimal128 A) + -- Runtime Function: double __bid_trunctddf (_Decimal128 A) + -- Runtime Function: long double __dpd_extendsdxf (_Decimal32 A) + -- Runtime Function: long double __bid_extendsdxf (_Decimal32 A) + -- Runtime Function: long double __dpd_extendddxf (_Decimal64 A) + -- Runtime Function: long double __bid_extendddxf (_Decimal64 A) + -- Runtime Function: long double __dpd_trunctdxf (_Decimal128 A) + -- Runtime Function: long double __bid_trunctdxf (_Decimal128 A) + -- Runtime Function: long double __dpd_extendsdtf (_Decimal32 A) + -- Runtime Function: long double __bid_extendsdtf (_Decimal32 A) + -- Runtime Function: long double __dpd_extendddtf (_Decimal64 A) + -- Runtime Function: long double __bid_extendddtf (_Decimal64 A) + These functions convert the value of A from a decimal floating type + to a binary floating type of a different size. + + -- Runtime Function: _Decimal32 __dpd_extendsfsd (float A) + -- Runtime Function: _Decimal32 __bid_extendsfsd (float A) + -- Runtime Function: _Decimal64 __dpd_extenddfdd (double A) + -- Runtime Function: _Decimal64 __bid_extenddfdd (double A) + -- Runtime Function: _Decimal128 __dpd_extendtftd (long double A) + -- Runtime Function: _Decimal128 __bid_extendtftd (long double A) + -- Runtime Function: float __dpd_truncsdsf (_Decimal32 A) + -- Runtime Function: float __bid_truncsdsf (_Decimal32 A) + -- Runtime Function: double __dpd_truncdddf (_Decimal64 A) + -- Runtime Function: double __bid_truncdddf (_Decimal64 A) + -- Runtime Function: long double __dpd_trunctdtf (_Decimal128 A) + -- Runtime Function: long double __bid_trunctdtf (_Decimal128 A) + These functions convert the value of A between decimal and binary + floating types of the same size. + + -- Runtime Function: int __dpd_fixsdsi (_Decimal32 A) + -- Runtime Function: int __bid_fixsdsi (_Decimal32 A) + -- Runtime Function: int __dpd_fixddsi (_Decimal64 A) + -- Runtime Function: int __bid_fixddsi (_Decimal64 A) + -- Runtime Function: int __dpd_fixtdsi (_Decimal128 A) + -- Runtime Function: int __bid_fixtdsi (_Decimal128 A) + These functions convert A to a signed integer. + + -- Runtime Function: long __dpd_fixsddi (_Decimal32 A) + -- Runtime Function: long __bid_fixsddi (_Decimal32 A) + -- Runtime Function: long __dpd_fixdddi (_Decimal64 A) + -- Runtime Function: long __bid_fixdddi (_Decimal64 A) + -- Runtime Function: long __dpd_fixtddi (_Decimal128 A) + -- Runtime Function: long __bid_fixtddi (_Decimal128 A) + These functions convert A to a signed long. + + -- Runtime Function: unsigned int __dpd_fixunssdsi (_Decimal32 A) + -- Runtime Function: unsigned int __bid_fixunssdsi (_Decimal32 A) + -- Runtime Function: unsigned int __dpd_fixunsddsi (_Decimal64 A) + -- Runtime Function: unsigned int __bid_fixunsddsi (_Decimal64 A) + -- Runtime Function: unsigned int __dpd_fixunstdsi (_Decimal128 A) + -- Runtime Function: unsigned int __bid_fixunstdsi (_Decimal128 A) + These functions convert A to an unsigned integer. Negative values + all become zero. + + -- Runtime Function: unsigned long __dpd_fixunssddi (_Decimal32 A) + -- Runtime Function: unsigned long __bid_fixunssddi (_Decimal32 A) + -- Runtime Function: unsigned long __dpd_fixunsdddi (_Decimal64 A) + -- Runtime Function: unsigned long __bid_fixunsdddi (_Decimal64 A) + -- Runtime Function: unsigned long __dpd_fixunstddi (_Decimal128 A) + -- Runtime Function: unsigned long __bid_fixunstddi (_Decimal128 A) + These functions convert A to an unsigned long. Negative values + all become zero. + + -- Runtime Function: _Decimal32 __dpd_floatsisd (int I) + -- Runtime Function: _Decimal32 __bid_floatsisd (int I) + -- Runtime Function: _Decimal64 __dpd_floatsidd (int I) + -- Runtime Function: _Decimal64 __bid_floatsidd (int I) + -- Runtime Function: _Decimal128 __dpd_floatsitd (int I) + -- Runtime Function: _Decimal128 __bid_floatsitd (int I) + These functions convert I, a signed integer, to decimal floating + point. + + -- Runtime Function: _Decimal32 __dpd_floatdisd (long I) + -- Runtime Function: _Decimal32 __bid_floatdisd (long I) + -- Runtime Function: _Decimal64 __dpd_floatdidd (long I) + -- Runtime Function: _Decimal64 __bid_floatdidd (long I) + -- Runtime Function: _Decimal128 __dpd_floatditd (long I) + -- Runtime Function: _Decimal128 __bid_floatditd (long I) + These functions convert I, a signed long, to decimal floating + point. + + -- Runtime Function: _Decimal32 __dpd_floatunssisd (unsigned int I) + -- Runtime Function: _Decimal32 __bid_floatunssisd (unsigned int I) + -- Runtime Function: _Decimal64 __dpd_floatunssidd (unsigned int I) + -- Runtime Function: _Decimal64 __bid_floatunssidd (unsigned int I) + -- Runtime Function: _Decimal128 __dpd_floatunssitd (unsigned int I) + -- Runtime Function: _Decimal128 __bid_floatunssitd (unsigned int I) + These functions convert I, an unsigned integer, to decimal + floating point. + + -- Runtime Function: _Decimal32 __dpd_floatunsdisd (unsigned long I) + -- Runtime Function: _Decimal32 __bid_floatunsdisd (unsigned long I) + -- Runtime Function: _Decimal64 __dpd_floatunsdidd (unsigned long I) + -- Runtime Function: _Decimal64 __bid_floatunsdidd (unsigned long I) + -- Runtime Function: _Decimal128 __dpd_floatunsditd (unsigned long I) + -- Runtime Function: _Decimal128 __bid_floatunsditd (unsigned long I) + These functions convert I, an unsigned long, to decimal floating + point. + +4.3.3 Comparison functions +-------------------------- + + -- Runtime Function: int __dpd_unordsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_unordsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_unorddd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_unorddd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_unordtd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_unordtd2 (_Decimal128 A, _Decimal128 B) + These functions return a nonzero value if either argument is NaN, + otherwise 0. + + There is also a complete group of higher level functions which +correspond directly to comparison operators. They implement the ISO C +semantics for floating-point comparisons, taking NaN into account. Pay +careful attention to the return values defined for each set. Under the +hood, all of these routines are implemented as + + if (__bid_unordXd2 (a, b)) + return E; + return __bid_cmpXd2 (a, b); + +where E is a constant chosen to give the proper behavior for NaN. +Thus, the meaning of the return value is different for each set. Do +not rely on this implementation; only the semantics documented below +are guaranteed. + + -- Runtime Function: int __dpd_eqsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_eqsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_eqdd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_eqdd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_eqtd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_eqtd2 (_Decimal128 A, _Decimal128 B) + These functions return zero if neither argument is NaN, and A and + B are equal. + + -- Runtime Function: int __dpd_nesd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_nesd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_nedd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_nedd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_netd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_netd2 (_Decimal128 A, _Decimal128 B) + These functions return a nonzero value if either argument is NaN, + or if A and B are unequal. + + -- Runtime Function: int __dpd_gesd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_gesd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_gedd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_gedd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_getd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_getd2 (_Decimal128 A, _Decimal128 B) + These functions return a value greater than or equal to zero if + neither argument is NaN, and A is greater than or equal to B. + + -- Runtime Function: int __dpd_ltsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_ltsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_ltdd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_ltdd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_lttd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_lttd2 (_Decimal128 A, _Decimal128 B) + These functions return a value less than zero if neither argument + is NaN, and A is strictly less than B. + + -- Runtime Function: int __dpd_lesd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_lesd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_ledd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_ledd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_letd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_letd2 (_Decimal128 A, _Decimal128 B) + These functions return a value less than or equal to zero if + neither argument is NaN, and A is less than or equal to B. + + -- Runtime Function: int __dpd_gtsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __bid_gtsd2 (_Decimal32 A, _Decimal32 B) + -- Runtime Function: int __dpd_gtdd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __bid_gtdd2 (_Decimal64 A, _Decimal64 B) + -- Runtime Function: int __dpd_gttd2 (_Decimal128 A, _Decimal128 B) + -- Runtime Function: int __bid_gttd2 (_Decimal128 A, _Decimal128 B) + These functions return a value greater than zero if neither + argument is NaN, and A is strictly greater than B. + + +File: gccint.info, Node: Fixed-point fractional library routines, Next: Exception handling routines, Prev: Decimal float library routines, Up: Libgcc + +4.4 Routines for fixed-point fractional emulation +================================================= + +The software fixed-point library implements fixed-point fractional +arithmetic, and is only activated on selected targets. + + For ease of comprehension `fract' is an alias for the `_Fract' type, +`accum' an alias for `_Accum', and `sat' an alias for `_Sat'. + + For illustrative purposes, in this section the fixed-point fractional +type `short fract' is assumed to correspond to machine mode `QQmode'; +`unsigned short fract' to `UQQmode'; `fract' to `HQmode'; +`unsigned fract' to `UHQmode'; `long fract' to `SQmode'; +`unsigned long fract' to `USQmode'; `long long fract' to `DQmode'; and +`unsigned long long fract' to `UDQmode'. Similarly the fixed-point +accumulator type `short accum' corresponds to `HAmode'; +`unsigned short accum' to `UHAmode'; `accum' to `SAmode'; +`unsigned accum' to `USAmode'; `long accum' to `DAmode'; +`unsigned long accum' to `UDAmode'; `long long accum' to `TAmode'; and +`unsigned long long accum' to `UTAmode'. + +4.4.1 Arithmetic functions +-------------------------- + + -- Runtime Function: short fract __addqq3 (short fract A, short fract + B) + -- Runtime Function: fract __addhq3 (fract A, fract B) + -- Runtime Function: long fract __addsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __adddq3 (long long fract A, long + long fract B) + -- Runtime Function: unsigned short fract __adduqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __adduhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __addusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __addudq3 (unsigned long + long fract A, unsigned long long fract B) + -- Runtime Function: short accum __addha3 (short accum A, short accum + B) + -- Runtime Function: accum __addsa3 (accum A, accum B) + -- Runtime Function: long accum __addda3 (long accum A, long accum B) + -- Runtime Function: long long accum __addta3 (long long accum A, long + long accum B) + -- Runtime Function: unsigned short accum __adduha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __addusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __adduda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __adduta3 (unsigned long + long accum A, unsigned long long accum B) + These functions return the sum of A and B. + + -- Runtime Function: short fract __ssaddqq3 (short fract A, short + fract B) + -- Runtime Function: fract __ssaddhq3 (fract A, fract B) + -- Runtime Function: long fract __ssaddsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __ssadddq3 (long long fract A, + long long fract B) + -- Runtime Function: short accum __ssaddha3 (short accum A, short + accum B) + -- Runtime Function: accum __ssaddsa3 (accum A, accum B) + -- Runtime Function: long accum __ssaddda3 (long accum A, long accum B) + -- Runtime Function: long long accum __ssaddta3 (long long accum A, + long long accum B) + These functions return the sum of A and B with signed saturation. + + -- Runtime Function: unsigned short fract __usadduqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __usadduhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __usaddusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __usaddudq3 (unsigned + long long fract A, unsigned long long fract B) + -- Runtime Function: unsigned short accum __usadduha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __usaddusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __usadduda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __usadduta3 (unsigned + long long accum A, unsigned long long accum B) + These functions return the sum of A and B with unsigned saturation. + + -- Runtime Function: short fract __subqq3 (short fract A, short fract + B) + -- Runtime Function: fract __subhq3 (fract A, fract B) + -- Runtime Function: long fract __subsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __subdq3 (long long fract A, long + long fract B) + -- Runtime Function: unsigned short fract __subuqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __subuhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __subusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __subudq3 (unsigned long + long fract A, unsigned long long fract B) + -- Runtime Function: short accum __subha3 (short accum A, short accum + B) + -- Runtime Function: accum __subsa3 (accum A, accum B) + -- Runtime Function: long accum __subda3 (long accum A, long accum B) + -- Runtime Function: long long accum __subta3 (long long accum A, long + long accum B) + -- Runtime Function: unsigned short accum __subuha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __subusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __subuda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __subuta3 (unsigned long + long accum A, unsigned long long accum B) + These functions return the difference of A and B; that is, `A - B'. + + -- Runtime Function: short fract __sssubqq3 (short fract A, short + fract B) + -- Runtime Function: fract __sssubhq3 (fract A, fract B) + -- Runtime Function: long fract __sssubsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __sssubdq3 (long long fract A, + long long fract B) + -- Runtime Function: short accum __sssubha3 (short accum A, short + accum B) + -- Runtime Function: accum __sssubsa3 (accum A, accum B) + -- Runtime Function: long accum __sssubda3 (long accum A, long accum B) + -- Runtime Function: long long accum __sssubta3 (long long accum A, + long long accum B) + These functions return the difference of A and B with signed + saturation; that is, `A - B'. + + -- Runtime Function: unsigned short fract __ussubuqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __ussubuhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __ussubusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __ussubudq3 (unsigned + long long fract A, unsigned long long fract B) + -- Runtime Function: unsigned short accum __ussubuha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __ussubusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __ussubuda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __ussubuta3 (unsigned + long long accum A, unsigned long long accum B) + These functions return the difference of A and B with unsigned + saturation; that is, `A - B'. + + -- Runtime Function: short fract __mulqq3 (short fract A, short fract + B) + -- Runtime Function: fract __mulhq3 (fract A, fract B) + -- Runtime Function: long fract __mulsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __muldq3 (long long fract A, long + long fract B) + -- Runtime Function: unsigned short fract __muluqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __muluhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __mulusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __muludq3 (unsigned long + long fract A, unsigned long long fract B) + -- Runtime Function: short accum __mulha3 (short accum A, short accum + B) + -- Runtime Function: accum __mulsa3 (accum A, accum B) + -- Runtime Function: long accum __mulda3 (long accum A, long accum B) + -- Runtime Function: long long accum __multa3 (long long accum A, long + long accum B) + -- Runtime Function: unsigned short accum __muluha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __mulusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __muluda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __muluta3 (unsigned long + long accum A, unsigned long long accum B) + These functions return the product of A and B. + + -- Runtime Function: short fract __ssmulqq3 (short fract A, short + fract B) + -- Runtime Function: fract __ssmulhq3 (fract A, fract B) + -- Runtime Function: long fract __ssmulsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __ssmuldq3 (long long fract A, + long long fract B) + -- Runtime Function: short accum __ssmulha3 (short accum A, short + accum B) + -- Runtime Function: accum __ssmulsa3 (accum A, accum B) + -- Runtime Function: long accum __ssmulda3 (long accum A, long accum B) + -- Runtime Function: long long accum __ssmulta3 (long long accum A, + long long accum B) + These functions return the product of A and B with signed + saturation. + + -- Runtime Function: unsigned short fract __usmuluqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __usmuluhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __usmulusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __usmuludq3 (unsigned + long long fract A, unsigned long long fract B) + -- Runtime Function: unsigned short accum __usmuluha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __usmulusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __usmuluda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __usmuluta3 (unsigned + long long accum A, unsigned long long accum B) + These functions return the product of A and B with unsigned + saturation. + + -- Runtime Function: short fract __divqq3 (short fract A, short fract + B) + -- Runtime Function: fract __divhq3 (fract A, fract B) + -- Runtime Function: long fract __divsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __divdq3 (long long fract A, long + long fract B) + -- Runtime Function: short accum __divha3 (short accum A, short accum + B) + -- Runtime Function: accum __divsa3 (accum A, accum B) + -- Runtime Function: long accum __divda3 (long accum A, long accum B) + -- Runtime Function: long long accum __divta3 (long long accum A, long + long accum B) + These functions return the quotient of the signed division of A + and B. + + -- Runtime Function: unsigned short fract __udivuqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __udivuhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __udivusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __udivudq3 (unsigned + long long fract A, unsigned long long fract B) + -- Runtime Function: unsigned short accum __udivuha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __udivusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __udivuda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __udivuta3 (unsigned + long long accum A, unsigned long long accum B) + These functions return the quotient of the unsigned division of A + and B. + + -- Runtime Function: short fract __ssdivqq3 (short fract A, short + fract B) + -- Runtime Function: fract __ssdivhq3 (fract A, fract B) + -- Runtime Function: long fract __ssdivsq3 (long fract A, long fract B) + -- Runtime Function: long long fract __ssdivdq3 (long long fract A, + long long fract B) + -- Runtime Function: short accum __ssdivha3 (short accum A, short + accum B) + -- Runtime Function: accum __ssdivsa3 (accum A, accum B) + -- Runtime Function: long accum __ssdivda3 (long accum A, long accum B) + -- Runtime Function: long long accum __ssdivta3 (long long accum A, + long long accum B) + These functions return the quotient of the signed division of A + and B with signed saturation. + + -- Runtime Function: unsigned short fract __usdivuqq3 (unsigned short + fract A, unsigned short fract B) + -- Runtime Function: unsigned fract __usdivuhq3 (unsigned fract A, + unsigned fract B) + -- Runtime Function: unsigned long fract __usdivusq3 (unsigned long + fract A, unsigned long fract B) + -- Runtime Function: unsigned long long fract __usdivudq3 (unsigned + long long fract A, unsigned long long fract B) + -- Runtime Function: unsigned short accum __usdivuha3 (unsigned short + accum A, unsigned short accum B) + -- Runtime Function: unsigned accum __usdivusa3 (unsigned accum A, + unsigned accum B) + -- Runtime Function: unsigned long accum __usdivuda3 (unsigned long + accum A, unsigned long accum B) + -- Runtime Function: unsigned long long accum __usdivuta3 (unsigned + long long accum A, unsigned long long accum B) + These functions return the quotient of the unsigned division of A + and B with unsigned saturation. + + -- Runtime Function: short fract __negqq2 (short fract A) + -- Runtime Function: fract __neghq2 (fract A) + -- Runtime Function: long fract __negsq2 (long fract A) + -- Runtime Function: long long fract __negdq2 (long long fract A) + -- Runtime Function: unsigned short fract __neguqq2 (unsigned short + fract A) + -- Runtime Function: unsigned fract __neguhq2 (unsigned fract A) + -- Runtime Function: unsigned long fract __negusq2 (unsigned long + fract A) + -- Runtime Function: unsigned long long fract __negudq2 (unsigned long + long fract A) + -- Runtime Function: short accum __negha2 (short accum A) + -- Runtime Function: accum __negsa2 (accum A) + -- Runtime Function: long accum __negda2 (long accum A) + -- Runtime Function: long long accum __negta2 (long long accum A) + -- Runtime Function: unsigned short accum __neguha2 (unsigned short + accum A) + -- Runtime Function: unsigned accum __negusa2 (unsigned accum A) + -- Runtime Function: unsigned long accum __neguda2 (unsigned long + accum A) + -- Runtime Function: unsigned long long accum __neguta2 (unsigned long + long accum A) + These functions return the negation of A. + + -- Runtime Function: short fract __ssnegqq2 (short fract A) + -- Runtime Function: fract __ssneghq2 (fract A) + -- Runtime Function: long fract __ssnegsq2 (long fract A) + -- Runtime Function: long long fract __ssnegdq2 (long long fract A) + -- Runtime Function: short accum __ssnegha2 (short accum A) + -- Runtime Function: accum __ssnegsa2 (accum A) + -- Runtime Function: long accum __ssnegda2 (long accum A) + -- Runtime Function: long long accum __ssnegta2 (long long accum A) + These functions return the negation of A with signed saturation. + + -- Runtime Function: unsigned short fract __usneguqq2 (unsigned short + fract A) + -- Runtime Function: unsigned fract __usneguhq2 (unsigned fract A) + -- Runtime Function: unsigned long fract __usnegusq2 (unsigned long + fract A) + -- Runtime Function: unsigned long long fract __usnegudq2 (unsigned + long long fract A) + -- Runtime Function: unsigned short accum __usneguha2 (unsigned short + accum A) + -- Runtime Function: unsigned accum __usnegusa2 (unsigned accum A) + -- Runtime Function: unsigned long accum __usneguda2 (unsigned long + accum A) + -- Runtime Function: unsigned long long accum __usneguta2 (unsigned + long long accum A) + These functions return the negation of A with unsigned saturation. + + -- Runtime Function: short fract __ashlqq3 (short fract A, int B) + -- Runtime Function: fract __ashlhq3 (fract A, int B) + -- Runtime Function: long fract __ashlsq3 (long fract A, int B) + -- Runtime Function: long long fract __ashldq3 (long long fract A, int + B) + -- Runtime Function: unsigned short fract __ashluqq3 (unsigned short + fract A, int B) + -- Runtime Function: unsigned fract __ashluhq3 (unsigned fract A, int + B) + -- Runtime Function: unsigned long fract __ashlusq3 (unsigned long + fract A, int B) + -- Runtime Function: unsigned long long fract __ashludq3 (unsigned + long long fract A, int B) + -- Runtime Function: short accum __ashlha3 (short accum A, int B) + -- Runtime Function: accum __ashlsa3 (accum A, int B) + -- Runtime Function: long accum __ashlda3 (long accum A, int B) + -- Runtime Function: long long accum __ashlta3 (long long accum A, int + B) + -- Runtime Function: unsigned short accum __ashluha3 (unsigned short + accum A, int B) + -- Runtime Function: unsigned accum __ashlusa3 (unsigned accum A, int + B) + -- Runtime Function: unsigned long accum __ashluda3 (unsigned long + accum A, int B) + -- Runtime Function: unsigned long long accum __ashluta3 (unsigned + long long accum A, int B) + These functions return the result of shifting A left by B bits. + + -- Runtime Function: short fract __ashrqq3 (short fract A, int B) + -- Runtime Function: fract __ashrhq3 (fract A, int B) + -- Runtime Function: long fract __ashrsq3 (long fract A, int B) + -- Runtime Function: long long fract __ashrdq3 (long long fract A, int + B) + -- Runtime Function: short accum __ashrha3 (short accum A, int B) + -- Runtime Function: accum __ashrsa3 (accum A, int B) + -- Runtime Function: long accum __ashrda3 (long accum A, int B) + -- Runtime Function: long long accum __ashrta3 (long long accum A, int + B) + These functions return the result of arithmetically shifting A + right by B bits. + + -- Runtime Function: unsigned short fract __lshruqq3 (unsigned short + fract A, int B) + -- Runtime Function: unsigned fract __lshruhq3 (unsigned fract A, int + B) + -- Runtime Function: unsigned long fract __lshrusq3 (unsigned long + fract A, int B) + -- Runtime Function: unsigned long long fract __lshrudq3 (unsigned + long long fract A, int B) + -- Runtime Function: unsigned short accum __lshruha3 (unsigned short + accum A, int B) + -- Runtime Function: unsigned accum __lshrusa3 (unsigned accum A, int + B) + -- Runtime Function: unsigned long accum __lshruda3 (unsigned long + accum A, int B) + -- Runtime Function: unsigned long long accum __lshruta3 (unsigned + long long accum A, int B) + These functions return the result of logically shifting A right by + B bits. + + -- Runtime Function: fract __ssashlhq3 (fract A, int B) + -- Runtime Function: long fract __ssashlsq3 (long fract A, int B) + -- Runtime Function: long long fract __ssashldq3 (long long fract A, + int B) + -- Runtime Function: short accum __ssashlha3 (short accum A, int B) + -- Runtime Function: accum __ssashlsa3 (accum A, int B) + -- Runtime Function: long accum __ssashlda3 (long accum A, int B) + -- Runtime Function: long long accum __ssashlta3 (long long accum A, + int B) + These functions return the result of shifting A left by B bits + with signed saturation. + + -- Runtime Function: unsigned short fract __usashluqq3 (unsigned short + fract A, int B) + -- Runtime Function: unsigned fract __usashluhq3 (unsigned fract A, + int B) + -- Runtime Function: unsigned long fract __usashlusq3 (unsigned long + fract A, int B) + -- Runtime Function: unsigned long long fract __usashludq3 (unsigned + long long fract A, int B) + -- Runtime Function: unsigned short accum __usashluha3 (unsigned short + accum A, int B) + -- Runtime Function: unsigned accum __usashlusa3 (unsigned accum A, + int B) + -- Runtime Function: unsigned long accum __usashluda3 (unsigned long + accum A, int B) + -- Runtime Function: unsigned long long accum __usashluta3 (unsigned + long long accum A, int B) + These functions return the result of shifting A left by B bits + with unsigned saturation. + +4.4.2 Comparison functions +-------------------------- + +The following functions implement fixed-point comparisons. These +functions implement a low-level compare, upon which the higher level +comparison operators (such as less than and greater than or equal to) +can be constructed. The returned values lie in the range zero to two, +to allow the high-level operators to be implemented by testing the +returned result using either signed or unsigned comparison. + + -- Runtime Function: int __cmpqq2 (short fract A, short fract B) + -- Runtime Function: int __cmphq2 (fract A, fract B) + -- Runtime Function: int __cmpsq2 (long fract A, long fract B) + -- Runtime Function: int __cmpdq2 (long long fract A, long long fract + B) + -- Runtime Function: int __cmpuqq2 (unsigned short fract A, unsigned + short fract B) + -- Runtime Function: int __cmpuhq2 (unsigned fract A, unsigned fract B) + -- Runtime Function: int __cmpusq2 (unsigned long fract A, unsigned + long fract B) + -- Runtime Function: int __cmpudq2 (unsigned long long fract A, + unsigned long long fract B) + -- Runtime Function: int __cmpha2 (short accum A, short accum B) + -- Runtime Function: int __cmpsa2 (accum A, accum B) + -- Runtime Function: int __cmpda2 (long accum A, long accum B) + -- Runtime Function: int __cmpta2 (long long accum A, long long accum + B) + -- Runtime Function: int __cmpuha2 (unsigned short accum A, unsigned + short accum B) + -- Runtime Function: int __cmpusa2 (unsigned accum A, unsigned accum B) + -- Runtime Function: int __cmpuda2 (unsigned long accum A, unsigned + long accum B) + -- Runtime Function: int __cmputa2 (unsigned long long accum A, + unsigned long long accum B) + These functions perform a signed or unsigned comparison of A and B + (depending on the selected machine mode). If A is less than B, + they return 0; if A is greater than B, they return 2; and if A and + B are equal they return 1. + +4.4.3 Conversion functions +-------------------------- + + -- Runtime Function: fract __fractqqhq2 (short fract A) + -- Runtime Function: long fract __fractqqsq2 (short fract A) + -- Runtime Function: long long fract __fractqqdq2 (short fract A) + -- Runtime Function: short accum __fractqqha (short fract A) + -- Runtime Function: accum __fractqqsa (short fract A) + -- Runtime Function: long accum __fractqqda (short fract A) + -- Runtime Function: long long accum __fractqqta (short fract A) + -- Runtime Function: unsigned short fract __fractqquqq (short fract A) + -- Runtime Function: unsigned fract __fractqquhq (short fract A) + -- Runtime Function: unsigned long fract __fractqqusq (short fract A) + -- Runtime Function: unsigned long long fract __fractqqudq (short + fract A) + -- Runtime Function: unsigned short accum __fractqquha (short fract A) + -- Runtime Function: unsigned accum __fractqqusa (short fract A) + -- Runtime Function: unsigned long accum __fractqquda (short fract A) + -- Runtime Function: unsigned long long accum __fractqquta (short + fract A) + -- Runtime Function: signed char __fractqqqi (short fract A) + -- Runtime Function: short __fractqqhi (short fract A) + -- Runtime Function: int __fractqqsi (short fract A) + -- Runtime Function: long __fractqqdi (short fract A) + -- Runtime Function: long long __fractqqti (short fract A) + -- Runtime Function: float __fractqqsf (short fract A) + -- Runtime Function: double __fractqqdf (short fract A) + -- Runtime Function: short fract __fracthqqq2 (fract A) + -- Runtime Function: long fract __fracthqsq2 (fract A) + -- Runtime Function: long long fract __fracthqdq2 (fract A) + -- Runtime Function: short accum __fracthqha (fract A) + -- Runtime Function: accum __fracthqsa (fract A) + -- Runtime Function: long accum __fracthqda (fract A) + -- Runtime Function: long long accum __fracthqta (fract A) + -- Runtime Function: unsigned short fract __fracthquqq (fract A) + -- Runtime Function: unsigned fract __fracthquhq (fract A) + -- Runtime Function: unsigned long fract __fracthqusq (fract A) + -- Runtime Function: unsigned long long fract __fracthqudq (fract A) + -- Runtime Function: unsigned short accum __fracthquha (fract A) + -- Runtime Function: unsigned accum __fracthqusa (fract A) + -- Runtime Function: unsigned long accum __fracthquda (fract A) + -- Runtime Function: unsigned long long accum __fracthquta (fract A) + -- Runtime Function: signed char __fracthqqi (fract A) + -- Runtime Function: short __fracthqhi (fract A) + -- Runtime Function: int __fracthqsi (fract A) + -- Runtime Function: long __fracthqdi (fract A) + -- Runtime Function: long long __fracthqti (fract A) + -- Runtime Function: float __fracthqsf (fract A) + -- Runtime Function: double __fracthqdf (fract A) + -- Runtime Function: short fract __fractsqqq2 (long fract A) + -- Runtime Function: fract __fractsqhq2 (long fract A) + -- Runtime Function: long long fract __fractsqdq2 (long fract A) + -- Runtime Function: short accum __fractsqha (long fract A) + -- Runtime Function: accum __fractsqsa (long fract A) + -- Runtime Function: long accum __fractsqda (long fract A) + -- Runtime Function: long long accum __fractsqta (long fract A) + -- Runtime Function: unsigned short fract __fractsquqq (long fract A) + -- Runtime Function: unsigned fract __fractsquhq (long fract A) + -- Runtime Function: unsigned long fract __fractsqusq (long fract A) + -- Runtime Function: unsigned long long fract __fractsqudq (long fract + A) + -- Runtime Function: unsigned short accum __fractsquha (long fract A) + -- Runtime Function: unsigned accum __fractsqusa (long fract A) + -- Runtime Function: unsigned long accum __fractsquda (long fract A) + -- Runtime Function: unsigned long long accum __fractsquta (long fract + A) + -- Runtime Function: signed char __fractsqqi (long fract A) + -- Runtime Function: short __fractsqhi (long fract A) + -- Runtime Function: int __fractsqsi (long fract A) + -- Runtime Function: long __fractsqdi (long fract A) + -- Runtime Function: long long __fractsqti (long fract A) + -- Runtime Function: float __fractsqsf (long fract A) + -- Runtime Function: double __fractsqdf (long fract A) + -- Runtime Function: short fract __fractdqqq2 (long long fract A) + -- Runtime Function: fract __fractdqhq2 (long long fract A) + -- Runtime Function: long fract __fractdqsq2 (long long fract A) + -- Runtime Function: short accum __fractdqha (long long fract A) + -- Runtime Function: accum __fractdqsa (long long fract A) + -- Runtime Function: long accum __fractdqda (long long fract A) + -- Runtime Function: long long accum __fractdqta (long long fract A) + -- Runtime Function: unsigned short fract __fractdquqq (long long + fract A) + -- Runtime Function: unsigned fract __fractdquhq (long long fract A) + -- Runtime Function: unsigned long fract __fractdqusq (long long fract + A) + -- Runtime Function: unsigned long long fract __fractdqudq (long long + fract A) + -- Runtime Function: unsigned short accum __fractdquha (long long + fract A) + -- Runtime Function: unsigned accum __fractdqusa (long long fract A) + -- Runtime Function: unsigned long accum __fractdquda (long long fract + A) + -- Runtime Function: unsigned long long accum __fractdquta (long long + fract A) + -- Runtime Function: signed char __fractdqqi (long long fract A) + -- Runtime Function: short __fractdqhi (long long fract A) + -- Runtime Function: int __fractdqsi (long long fract A) + -- Runtime Function: long __fractdqdi (long long fract A) + -- Runtime Function: long long __fractdqti (long long fract A) + -- Runtime Function: float __fractdqsf (long long fract A) + -- Runtime Function: double __fractdqdf (long long fract A) + -- Runtime Function: short fract __fracthaqq (short accum A) + -- Runtime Function: fract __fracthahq (short accum A) + -- Runtime Function: long fract __fracthasq (short accum A) + -- Runtime Function: long long fract __fracthadq (short accum A) + -- Runtime Function: accum __fracthasa2 (short accum A) + -- Runtime Function: long accum __fracthada2 (short accum A) + -- Runtime Function: long long accum __fracthata2 (short accum A) + -- Runtime Function: unsigned short fract __fracthauqq (short accum A) + -- Runtime Function: unsigned fract __fracthauhq (short accum A) + -- Runtime Function: unsigned long fract __fracthausq (short accum A) + -- Runtime Function: unsigned long long fract __fracthaudq (short + accum A) + -- Runtime Function: unsigned short accum __fracthauha (short accum A) + -- Runtime Function: unsigned accum __fracthausa (short accum A) + -- Runtime Function: unsigned long accum __fracthauda (short accum A) + -- Runtime Function: unsigned long long accum __fracthauta (short + accum A) + -- Runtime Function: signed char __fracthaqi (short accum A) + -- Runtime Function: short __fracthahi (short accum A) + -- Runtime Function: int __fracthasi (short accum A) + -- Runtime Function: long __fracthadi (short accum A) + -- Runtime Function: long long __fracthati (short accum A) + -- Runtime Function: float __fracthasf (short accum A) + -- Runtime Function: double __fracthadf (short accum A) + -- Runtime Function: short fract __fractsaqq (accum A) + -- Runtime Function: fract __fractsahq (accum A) + -- Runtime Function: long fract __fractsasq (accum A) + -- Runtime Function: long long fract __fractsadq (accum A) + -- Runtime Function: short accum __fractsaha2 (accum A) + -- Runtime Function: long accum __fractsada2 (accum A) + -- Runtime Function: long long accum __fractsata2 (accum A) + -- Runtime Function: unsigned short fract __fractsauqq (accum A) + -- Runtime Function: unsigned fract __fractsauhq (accum A) + -- Runtime Function: unsigned long fract __fractsausq (accum A) + -- Runtime Function: unsigned long long fract __fractsaudq (accum A) + -- Runtime Function: unsigned short accum __fractsauha (accum A) + -- Runtime Function: unsigned accum __fractsausa (accum A) + -- Runtime Function: unsigned long accum __fractsauda (accum A) + -- Runtime Function: unsigned long long accum __fractsauta (accum A) + -- Runtime Function: signed char __fractsaqi (accum A) + -- Runtime Function: short __fractsahi (accum A) + -- Runtime Function: int __fractsasi (accum A) + -- Runtime Function: long __fractsadi (accum A) + -- Runtime Function: long long __fractsati (accum A) + -- Runtime Function: float __fractsasf (accum A) + -- Runtime Function: double __fractsadf (accum A) + -- Runtime Function: short fract __fractdaqq (long accum A) + -- Runtime Function: fract __fractdahq (long accum A) + -- Runtime Function: long fract __fractdasq (long accum A) + -- Runtime Function: long long fract __fractdadq (long accum A) + -- Runtime Function: short accum __fractdaha2 (long accum A) + -- Runtime Function: accum __fractdasa2 (long accum A) + -- Runtime Function: long long accum __fractdata2 (long accum A) + -- Runtime Function: unsigned short fract __fractdauqq (long accum A) + -- Runtime Function: unsigned fract __fractdauhq (long accum A) + -- Runtime Function: unsigned long fract __fractdausq (long accum A) + -- Runtime Function: unsigned long long fract __fractdaudq (long accum + A) + -- Runtime Function: unsigned short accum __fractdauha (long accum A) + -- Runtime Function: unsigned accum __fractdausa (long accum A) + -- Runtime Function: unsigned long accum __fractdauda (long accum A) + -- Runtime Function: unsigned long long accum __fractdauta (long accum + A) + -- Runtime Function: signed char __fractdaqi (long accum A) + -- Runtime Function: short __fractdahi (long accum A) + -- Runtime Function: int __fractdasi (long accum A) + -- Runtime Function: long __fractdadi (long accum A) + -- Runtime Function: long long __fractdati (long accum A) + -- Runtime Function: float __fractdasf (long accum A) + -- Runtime Function: double __fractdadf (long accum A) + -- Runtime Function: short fract __fracttaqq (long long accum A) + -- Runtime Function: fract __fracttahq (long long accum A) + -- Runtime Function: long fract __fracttasq (long long accum A) + -- Runtime Function: long long fract __fracttadq (long long accum A) + -- Runtime Function: short accum __fracttaha2 (long long accum A) + -- Runtime Function: accum __fracttasa2 (long long accum A) + -- Runtime Function: long accum __fracttada2 (long long accum A) + -- Runtime Function: unsigned short fract __fracttauqq (long long + accum A) + -- Runtime Function: unsigned fract __fracttauhq (long long accum A) + -- Runtime Function: unsigned long fract __fracttausq (long long accum + A) + -- Runtime Function: unsigned long long fract __fracttaudq (long long + accum A) + -- Runtime Function: unsigned short accum __fracttauha (long long + accum A) + -- Runtime Function: unsigned accum __fracttausa (long long accum A) + -- Runtime Function: unsigned long accum __fracttauda (long long accum + A) + -- Runtime Function: unsigned long long accum __fracttauta (long long + accum A) + -- Runtime Function: signed char __fracttaqi (long long accum A) + -- Runtime Function: short __fracttahi (long long accum A) + -- Runtime Function: int __fracttasi (long long accum A) + -- Runtime Function: long __fracttadi (long long accum A) + -- Runtime Function: long long __fracttati (long long accum A) + -- Runtime Function: float __fracttasf (long long accum A) + -- Runtime Function: double __fracttadf (long long accum A) + -- Runtime Function: short fract __fractuqqqq (unsigned short fract A) + -- Runtime Function: fract __fractuqqhq (unsigned short fract A) + -- Runtime Function: long fract __fractuqqsq (unsigned short fract A) + -- Runtime Function: long long fract __fractuqqdq (unsigned short + fract A) + -- Runtime Function: short accum __fractuqqha (unsigned short fract A) + -- Runtime Function: accum __fractuqqsa (unsigned short fract A) + -- Runtime Function: long accum __fractuqqda (unsigned short fract A) + -- Runtime Function: long long accum __fractuqqta (unsigned short + fract A) + -- Runtime Function: unsigned fract __fractuqquhq2 (unsigned short + fract A) + -- Runtime Function: unsigned long fract __fractuqqusq2 (unsigned + short fract A) + -- Runtime Function: unsigned long long fract __fractuqqudq2 (unsigned + short fract A) + -- Runtime Function: unsigned short accum __fractuqquha (unsigned + short fract A) + -- Runtime Function: unsigned accum __fractuqqusa (unsigned short + fract A) + -- Runtime Function: unsigned long accum __fractuqquda (unsigned short + fract A) + -- Runtime Function: unsigned long long accum __fractuqquta (unsigned + short fract A) + -- Runtime Function: signed char __fractuqqqi (unsigned short fract A) + -- Runtime Function: short __fractuqqhi (unsigned short fract A) + -- Runtime Function: int __fractuqqsi (unsigned short fract A) + -- Runtime Function: long __fractuqqdi (unsigned short fract A) + -- Runtime Function: long long __fractuqqti (unsigned short fract A) + -- Runtime Function: float __fractuqqsf (unsigned short fract A) + -- Runtime Function: double __fractuqqdf (unsigned short fract A) + -- Runtime Function: short fract __fractuhqqq (unsigned fract A) + -- Runtime Function: fract __fractuhqhq (unsigned fract A) + -- Runtime Function: long fract __fractuhqsq (unsigned fract A) + -- Runtime Function: long long fract __fractuhqdq (unsigned fract A) + -- Runtime Function: short accum __fractuhqha (unsigned fract A) + -- Runtime Function: accum __fractuhqsa (unsigned fract A) + -- Runtime Function: long accum __fractuhqda (unsigned fract A) + -- Runtime Function: long long accum __fractuhqta (unsigned fract A) + -- Runtime Function: unsigned short fract __fractuhquqq2 (unsigned + fract A) + -- Runtime Function: unsigned long fract __fractuhqusq2 (unsigned + fract A) + -- Runtime Function: unsigned long long fract __fractuhqudq2 (unsigned + fract A) + -- Runtime Function: unsigned short accum __fractuhquha (unsigned + fract A) + -- Runtime Function: unsigned accum __fractuhqusa (unsigned fract A) + -- Runtime Function: unsigned long accum __fractuhquda (unsigned fract + A) + -- Runtime Function: unsigned long long accum __fractuhquta (unsigned + fract A) + -- Runtime Function: signed char __fractuhqqi (unsigned fract A) + -- Runtime Function: short __fractuhqhi (unsigned fract A) + -- Runtime Function: int __fractuhqsi (unsigned fract A) + -- Runtime Function: long __fractuhqdi (unsigned fract A) + -- Runtime Function: long long __fractuhqti (unsigned fract A) + -- Runtime Function: float __fractuhqsf (unsigned fract A) + -- Runtime Function: double __fractuhqdf (unsigned fract A) + -- Runtime Function: short fract __fractusqqq (unsigned long fract A) + -- Runtime Function: fract __fractusqhq (unsigned long fract A) + -- Runtime Function: long fract __fractusqsq (unsigned long fract A) + -- Runtime Function: long long fract __fractusqdq (unsigned long fract + A) + -- Runtime Function: short accum __fractusqha (unsigned long fract A) + -- Runtime Function: accum __fractusqsa (unsigned long fract A) + -- Runtime Function: long accum __fractusqda (unsigned long fract A) + -- Runtime Function: long long accum __fractusqta (unsigned long fract + A) + -- Runtime Function: unsigned short fract __fractusquqq2 (unsigned + long fract A) + -- Runtime Function: unsigned fract __fractusquhq2 (unsigned long + fract A) + -- Runtime Function: unsigned long long fract __fractusqudq2 (unsigned + long fract A) + -- Runtime Function: unsigned short accum __fractusquha (unsigned long + fract A) + -- Runtime Function: unsigned accum __fractusqusa (unsigned long fract + A) + -- Runtime Function: unsigned long accum __fractusquda (unsigned long + fract A) + -- Runtime Function: unsigned long long accum __fractusquta (unsigned + long fract A) + -- Runtime Function: signed char __fractusqqi (unsigned long fract A) + -- Runtime Function: short __fractusqhi (unsigned long fract A) + -- Runtime Function: int __fractusqsi (unsigned long fract A) + -- Runtime Function: long __fractusqdi (unsigned long fract A) + -- Runtime Function: long long __fractusqti (unsigned long fract A) + -- Runtime Function: float __fractusqsf (unsigned long fract A) + -- Runtime Function: double __fractusqdf (unsigned long fract A) + -- Runtime Function: short fract __fractudqqq (unsigned long long + fract A) + -- Runtime Function: fract __fractudqhq (unsigned long long fract A) + -- Runtime Function: long fract __fractudqsq (unsigned long long fract + A) + -- Runtime Function: long long fract __fractudqdq (unsigned long long + fract A) + -- Runtime Function: short accum __fractudqha (unsigned long long + fract A) + -- Runtime Function: accum __fractudqsa (unsigned long long fract A) + -- Runtime Function: long accum __fractudqda (unsigned long long fract + A) + -- Runtime Function: long long accum __fractudqta (unsigned long long + fract A) + -- Runtime Function: unsigned short fract __fractudquqq2 (unsigned + long long fract A) + -- Runtime Function: unsigned fract __fractudquhq2 (unsigned long long + fract A) + -- Runtime Function: unsigned long fract __fractudqusq2 (unsigned long + long fract A) + -- Runtime Function: unsigned short accum __fractudquha (unsigned long + long fract A) + -- Runtime Function: unsigned accum __fractudqusa (unsigned long long + fract A) + -- Runtime Function: unsigned long accum __fractudquda (unsigned long + long fract A) + -- Runtime Function: unsigned long long accum __fractudquta (unsigned + long long fract A) + -- Runtime Function: signed char __fractudqqi (unsigned long long + fract A) + -- Runtime Function: short __fractudqhi (unsigned long long fract A) + -- Runtime Function: int __fractudqsi (unsigned long long fract A) + -- Runtime Function: long __fractudqdi (unsigned long long fract A) + -- Runtime Function: long long __fractudqti (unsigned long long fract + A) + -- Runtime Function: float __fractudqsf (unsigned long long fract A) + -- Runtime Function: double __fractudqdf (unsigned long long fract A) + -- Runtime Function: short fract __fractuhaqq (unsigned short accum A) + -- Runtime Function: fract __fractuhahq (unsigned short accum A) + -- Runtime Function: long fract __fractuhasq (unsigned short accum A) + -- Runtime Function: long long fract __fractuhadq (unsigned short + accum A) + -- Runtime Function: short accum __fractuhaha (unsigned short accum A) + -- Runtime Function: accum __fractuhasa (unsigned short accum A) + -- Runtime Function: long accum __fractuhada (unsigned short accum A) + -- Runtime Function: long long accum __fractuhata (unsigned short + accum A) + -- Runtime Function: unsigned short fract __fractuhauqq (unsigned + short accum A) + -- Runtime Function: unsigned fract __fractuhauhq (unsigned short + accum A) + -- Runtime Function: unsigned long fract __fractuhausq (unsigned short + accum A) + -- Runtime Function: unsigned long long fract __fractuhaudq (unsigned + short accum A) + -- Runtime Function: unsigned accum __fractuhausa2 (unsigned short + accum A) + -- Runtime Function: unsigned long accum __fractuhauda2 (unsigned + short accum A) + -- Runtime Function: unsigned long long accum __fractuhauta2 (unsigned + short accum A) + -- Runtime Function: signed char __fractuhaqi (unsigned short accum A) + -- Runtime Function: short __fractuhahi (unsigned short accum A) + -- Runtime Function: int __fractuhasi (unsigned short accum A) + -- Runtime Function: long __fractuhadi (unsigned short accum A) + -- Runtime Function: long long __fractuhati (unsigned short accum A) + -- Runtime Function: float __fractuhasf (unsigned short accum A) + -- Runtime Function: double __fractuhadf (unsigned short accum A) + -- Runtime Function: short fract __fractusaqq (unsigned accum A) + -- Runtime Function: fract __fractusahq (unsigned accum A) + -- Runtime Function: long fract __fractusasq (unsigned accum A) + -- Runtime Function: long long fract __fractusadq (unsigned accum A) + -- Runtime Function: short accum __fractusaha (unsigned accum A) + -- Runtime Function: accum __fractusasa (unsigned accum A) + -- Runtime Function: long accum __fractusada (unsigned accum A) + -- Runtime Function: long long accum __fractusata (unsigned accum A) + -- Runtime Function: unsigned short fract __fractusauqq (unsigned + accum A) + -- Runtime Function: unsigned fract __fractusauhq (unsigned accum A) + -- Runtime Function: unsigned long fract __fractusausq (unsigned accum + A) + -- Runtime Function: unsigned long long fract __fractusaudq (unsigned + accum A) + -- Runtime Function: unsigned short accum __fractusauha2 (unsigned + accum A) + -- Runtime Function: unsigned long accum __fractusauda2 (unsigned + accum A) + -- Runtime Function: unsigned long long accum __fractusauta2 (unsigned + accum A) + -- Runtime Function: signed char __fractusaqi (unsigned accum A) + -- Runtime Function: short __fractusahi (unsigned accum A) + -- Runtime Function: int __fractusasi (unsigned accum A) + -- Runtime Function: long __fractusadi (unsigned accum A) + -- Runtime Function: long long __fractusati (unsigned accum A) + -- Runtime Function: float __fractusasf (unsigned accum A) + -- Runtime Function: double __fractusadf (unsigned accum A) + -- Runtime Function: short fract __fractudaqq (unsigned long accum A) + -- Runtime Function: fract __fractudahq (unsigned long accum A) + -- Runtime Function: long fract __fractudasq (unsigned long accum A) + -- Runtime Function: long long fract __fractudadq (unsigned long accum + A) + -- Runtime Function: short accum __fractudaha (unsigned long accum A) + -- Runtime Function: accum __fractudasa (unsigned long accum A) + -- Runtime Function: long accum __fractudada (unsigned long accum A) + -- Runtime Function: long long accum __fractudata (unsigned long accum + A) + -- Runtime Function: unsigned short fract __fractudauqq (unsigned long + accum A) + -- Runtime Function: unsigned fract __fractudauhq (unsigned long accum + A) + -- Runtime Function: unsigned long fract __fractudausq (unsigned long + accum A) + -- Runtime Function: unsigned long long fract __fractudaudq (unsigned + long accum A) + -- Runtime Function: unsigned short accum __fractudauha2 (unsigned + long accum A) + -- Runtime Function: unsigned accum __fractudausa2 (unsigned long + accum A) + -- Runtime Function: unsigned long long accum __fractudauta2 (unsigned + long accum A) + -- Runtime Function: signed char __fractudaqi (unsigned long accum A) + -- Runtime Function: short __fractudahi (unsigned long accum A) + -- Runtime Function: int __fractudasi (unsigned long accum A) + -- Runtime Function: long __fractudadi (unsigned long accum A) + -- Runtime Function: long long __fractudati (unsigned long accum A) + -- Runtime Function: float __fractudasf (unsigned long accum A) + -- Runtime Function: double __fractudadf (unsigned long accum A) + -- Runtime Function: short fract __fractutaqq (unsigned long long + accum A) + -- Runtime Function: fract __fractutahq (unsigned long long accum A) + -- Runtime Function: long fract __fractutasq (unsigned long long accum + A) + -- Runtime Function: long long fract __fractutadq (unsigned long long + accum A) + -- Runtime Function: short accum __fractutaha (unsigned long long + accum A) + -- Runtime Function: accum __fractutasa (unsigned long long accum A) + -- Runtime Function: long accum __fractutada (unsigned long long accum + A) + -- Runtime Function: long long accum __fractutata (unsigned long long + accum A) + -- Runtime Function: unsigned short fract __fractutauqq (unsigned long + long accum A) + -- Runtime Function: unsigned fract __fractutauhq (unsigned long long + accum A) + -- Runtime Function: unsigned long fract __fractutausq (unsigned long + long accum A) + -- Runtime Function: unsigned long long fract __fractutaudq (unsigned + long long accum A) + -- Runtime Function: unsigned short accum __fractutauha2 (unsigned + long long accum A) + -- Runtime Function: unsigned accum __fractutausa2 (unsigned long long + accum A) + -- Runtime Function: unsigned long accum __fractutauda2 (unsigned long + long accum A) + -- Runtime Function: signed char __fractutaqi (unsigned long long + accum A) + -- Runtime Function: short __fractutahi (unsigned long long accum A) + -- Runtime Function: int __fractutasi (unsigned long long accum A) + -- Runtime Function: long __fractutadi (unsigned long long accum A) + -- Runtime Function: long long __fractutati (unsigned long long accum + A) + -- Runtime Function: float __fractutasf (unsigned long long accum A) + -- Runtime Function: double __fractutadf (unsigned long long accum A) + -- Runtime Function: short fract __fractqiqq (signed char A) + -- Runtime Function: fract __fractqihq (signed char A) + -- Runtime Function: long fract __fractqisq (signed char A) + -- Runtime Function: long long fract __fractqidq (signed char A) + -- Runtime Function: short accum __fractqiha (signed char A) + -- Runtime Function: accum __fractqisa (signed char A) + -- Runtime Function: long accum __fractqida (signed char A) + -- Runtime Function: long long accum __fractqita (signed char A) + -- Runtime Function: unsigned short fract __fractqiuqq (signed char A) + -- Runtime Function: unsigned fract __fractqiuhq (signed char A) + -- Runtime Function: unsigned long fract __fractqiusq (signed char A) + -- Runtime Function: unsigned long long fract __fractqiudq (signed + char A) + -- Runtime Function: unsigned short accum __fractqiuha (signed char A) + -- Runtime Function: unsigned accum __fractqiusa (signed char A) + -- Runtime Function: unsigned long accum __fractqiuda (signed char A) + -- Runtime Function: unsigned long long accum __fractqiuta (signed + char A) + -- Runtime Function: short fract __fracthiqq (short A) + -- Runtime Function: fract __fracthihq (short A) + -- Runtime Function: long fract __fracthisq (short A) + -- Runtime Function: long long fract __fracthidq (short A) + -- Runtime Function: short accum __fracthiha (short A) + -- Runtime Function: accum __fracthisa (short A) + -- Runtime Function: long accum __fracthida (short A) + -- Runtime Function: long long accum __fracthita (short A) + -- Runtime Function: unsigned short fract __fracthiuqq (short A) + -- Runtime Function: unsigned fract __fracthiuhq (short A) + -- Runtime Function: unsigned long fract __fracthiusq (short A) + -- Runtime Function: unsigned long long fract __fracthiudq (short A) + -- Runtime Function: unsigned short accum __fracthiuha (short A) + -- Runtime Function: unsigned accum __fracthiusa (short A) + -- Runtime Function: unsigned long accum __fracthiuda (short A) + -- Runtime Function: unsigned long long accum __fracthiuta (short A) + -- Runtime Function: short fract __fractsiqq (int A) + -- Runtime Function: fract __fractsihq (int A) + -- Runtime Function: long fract __fractsisq (int A) + -- Runtime Function: long long fract __fractsidq (int A) + -- Runtime Function: short accum __fractsiha (int A) + -- Runtime Function: accum __fractsisa (int A) + -- Runtime Function: long accum __fractsida (int A) + -- Runtime Function: long long accum __fractsita (int A) + -- Runtime Function: unsigned short fract __fractsiuqq (int A) + -- Runtime Function: unsigned fract __fractsiuhq (int A) + -- Runtime Function: unsigned long fract __fractsiusq (int A) + -- Runtime Function: unsigned long long fract __fractsiudq (int A) + -- Runtime Function: unsigned short accum __fractsiuha (int A) + -- Runtime Function: unsigned accum __fractsiusa (int A) + -- Runtime Function: unsigned long accum __fractsiuda (int A) + -- Runtime Function: unsigned long long accum __fractsiuta (int A) + -- Runtime Function: short fract __fractdiqq (long A) + -- Runtime Function: fract __fractdihq (long A) + -- Runtime Function: long fract __fractdisq (long A) + -- Runtime Function: long long fract __fractdidq (long A) + -- Runtime Function: short accum __fractdiha (long A) + -- Runtime Function: accum __fractdisa (long A) + -- Runtime Function: long accum __fractdida (long A) + -- Runtime Function: long long accum __fractdita (long A) + -- Runtime Function: unsigned short fract __fractdiuqq (long A) + -- Runtime Function: unsigned fract __fractdiuhq (long A) + -- Runtime Function: unsigned long fract __fractdiusq (long A) + -- Runtime Function: unsigned long long fract __fractdiudq (long A) + -- Runtime Function: unsigned short accum __fractdiuha (long A) + -- Runtime Function: unsigned accum __fractdiusa (long A) + -- Runtime Function: unsigned long accum __fractdiuda (long A) + -- Runtime Function: unsigned long long accum __fractdiuta (long A) + -- Runtime Function: short fract __fracttiqq (long long A) + -- Runtime Function: fract __fracttihq (long long A) + -- Runtime Function: long fract __fracttisq (long long A) + -- Runtime Function: long long fract __fracttidq (long long A) + -- Runtime Function: short accum __fracttiha (long long A) + -- Runtime Function: accum __fracttisa (long long A) + -- Runtime Function: long accum __fracttida (long long A) + -- Runtime Function: long long accum __fracttita (long long A) + -- Runtime Function: unsigned short fract __fracttiuqq (long long A) + -- Runtime Function: unsigned fract __fracttiuhq (long long A) + -- Runtime Function: unsigned long fract __fracttiusq (long long A) + -- Runtime Function: unsigned long long fract __fracttiudq (long long + A) + -- Runtime Function: unsigned short accum __fracttiuha (long long A) + -- Runtime Function: unsigned accum __fracttiusa (long long A) + -- Runtime Function: unsigned long accum __fracttiuda (long long A) + -- Runtime Function: unsigned long long accum __fracttiuta (long long + A) + -- Runtime Function: short fract __fractsfqq (float A) + -- Runtime Function: fract __fractsfhq (float A) + -- Runtime Function: long fract __fractsfsq (float A) + -- Runtime Function: long long fract __fractsfdq (float A) + -- Runtime Function: short accum __fractsfha (float A) + -- Runtime Function: accum __fractsfsa (float A) + -- Runtime Function: long accum __fractsfda (float A) + -- Runtime Function: long long accum __fractsfta (float A) + -- Runtime Function: unsigned short fract __fractsfuqq (float A) + -- Runtime Function: unsigned fract __fractsfuhq (float A) + -- Runtime Function: unsigned long fract __fractsfusq (float A) + -- Runtime Function: unsigned long long fract __fractsfudq (float A) + -- Runtime Function: unsigned short accum __fractsfuha (float A) + -- Runtime Function: unsigned accum __fractsfusa (float A) + -- Runtime Function: unsigned long accum __fractsfuda (float A) + -- Runtime Function: unsigned long long accum __fractsfuta (float A) + -- Runtime Function: short fract __fractdfqq (double A) + -- Runtime Function: fract __fractdfhq (double A) + -- Runtime Function: long fract __fractdfsq (double A) + -- Runtime Function: long long fract __fractdfdq (double A) + -- Runtime Function: short accum __fractdfha (double A) + -- Runtime Function: accum __fractdfsa (double A) + -- Runtime Function: long accum __fractdfda (double A) + -- Runtime Function: long long accum __fractdfta (double A) + -- Runtime Function: unsigned short fract __fractdfuqq (double A) + -- Runtime Function: unsigned fract __fractdfuhq (double A) + -- Runtime Function: unsigned long fract __fractdfusq (double A) + -- Runtime Function: unsigned long long fract __fractdfudq (double A) + -- Runtime Function: unsigned short accum __fractdfuha (double A) + -- Runtime Function: unsigned accum __fractdfusa (double A) + -- Runtime Function: unsigned long accum __fractdfuda (double A) + -- Runtime Function: unsigned long long accum __fractdfuta (double A) + These functions convert from fractional and signed non-fractionals + to fractionals and signed non-fractionals, without saturation. + + -- Runtime Function: fract __satfractqqhq2 (short fract A) + -- Runtime Function: long fract __satfractqqsq2 (short fract A) + -- Runtime Function: long long fract __satfractqqdq2 (short fract A) + -- Runtime Function: short accum __satfractqqha (short fract A) + -- Runtime Function: accum __satfractqqsa (short fract A) + -- Runtime Function: long accum __satfractqqda (short fract A) + -- Runtime Function: long long accum __satfractqqta (short fract A) + -- Runtime Function: unsigned short fract __satfractqquqq (short fract + A) + -- Runtime Function: unsigned fract __satfractqquhq (short fract A) + -- Runtime Function: unsigned long fract __satfractqqusq (short fract + A) + -- Runtime Function: unsigned long long fract __satfractqqudq (short + fract A) + -- Runtime Function: unsigned short accum __satfractqquha (short fract + A) + -- Runtime Function: unsigned accum __satfractqqusa (short fract A) + -- Runtime Function: unsigned long accum __satfractqquda (short fract + A) + -- Runtime Function: unsigned long long accum __satfractqquta (short + fract A) + -- Runtime Function: short fract __satfracthqqq2 (fract A) + -- Runtime Function: long fract __satfracthqsq2 (fract A) + -- Runtime Function: long long fract __satfracthqdq2 (fract A) + -- Runtime Function: short accum __satfracthqha (fract A) + -- Runtime Function: accum __satfracthqsa (fract A) + -- Runtime Function: long accum __satfracthqda (fract A) + -- Runtime Function: long long accum __satfracthqta (fract A) + -- Runtime Function: unsigned short fract __satfracthquqq (fract A) + -- Runtime Function: unsigned fract __satfracthquhq (fract A) + -- Runtime Function: unsigned long fract __satfracthqusq (fract A) + -- Runtime Function: unsigned long long fract __satfracthqudq (fract A) + -- Runtime Function: unsigned short accum __satfracthquha (fract A) + -- Runtime Function: unsigned accum __satfracthqusa (fract A) + -- Runtime Function: unsigned long accum __satfracthquda (fract A) + -- Runtime Function: unsigned long long accum __satfracthquta (fract A) + -- Runtime Function: short fract __satfractsqqq2 (long fract A) + -- Runtime Function: fract __satfractsqhq2 (long fract A) + -- Runtime Function: long long fract __satfractsqdq2 (long fract A) + -- Runtime Function: short accum __satfractsqha (long fract A) + -- Runtime Function: accum __satfractsqsa (long fract A) + -- Runtime Function: long accum __satfractsqda (long fract A) + -- Runtime Function: long long accum __satfractsqta (long fract A) + -- Runtime Function: unsigned short fract __satfractsquqq (long fract + A) + -- Runtime Function: unsigned fract __satfractsquhq (long fract A) + -- Runtime Function: unsigned long fract __satfractsqusq (long fract A) + -- Runtime Function: unsigned long long fract __satfractsqudq (long + fract A) + -- Runtime Function: unsigned short accum __satfractsquha (long fract + A) + -- Runtime Function: unsigned accum __satfractsqusa (long fract A) + -- Runtime Function: unsigned long accum __satfractsquda (long fract A) + -- Runtime Function: unsigned long long accum __satfractsquta (long + fract A) + -- Runtime Function: short fract __satfractdqqq2 (long long fract A) + -- Runtime Function: fract __satfractdqhq2 (long long fract A) + -- Runtime Function: long fract __satfractdqsq2 (long long fract A) + -- Runtime Function: short accum __satfractdqha (long long fract A) + -- Runtime Function: accum __satfractdqsa (long long fract A) + -- Runtime Function: long accum __satfractdqda (long long fract A) + -- Runtime Function: long long accum __satfractdqta (long long fract A) + -- Runtime Function: unsigned short fract __satfractdquqq (long long + fract A) + -- Runtime Function: unsigned fract __satfractdquhq (long long fract A) + -- Runtime Function: unsigned long fract __satfractdqusq (long long + fract A) + -- Runtime Function: unsigned long long fract __satfractdqudq (long + long fract A) + -- Runtime Function: unsigned short accum __satfractdquha (long long + fract A) + -- Runtime Function: unsigned accum __satfractdqusa (long long fract A) + -- Runtime Function: unsigned long accum __satfractdquda (long long + fract A) + -- Runtime Function: unsigned long long accum __satfractdquta (long + long fract A) + -- Runtime Function: short fract __satfracthaqq (short accum A) + -- Runtime Function: fract __satfracthahq (short accum A) + -- Runtime Function: long fract __satfracthasq (short accum A) + -- Runtime Function: long long fract __satfracthadq (short accum A) + -- Runtime Function: accum __satfracthasa2 (short accum A) + -- Runtime Function: long accum __satfracthada2 (short accum A) + -- Runtime Function: long long accum __satfracthata2 (short accum A) + -- Runtime Function: unsigned short fract __satfracthauqq (short accum + A) + -- Runtime Function: unsigned fract __satfracthauhq (short accum A) + -- Runtime Function: unsigned long fract __satfracthausq (short accum + A) + -- Runtime Function: unsigned long long fract __satfracthaudq (short + accum A) + -- Runtime Function: unsigned short accum __satfracthauha (short accum + A) + -- Runtime Function: unsigned accum __satfracthausa (short accum A) + -- Runtime Function: unsigned long accum __satfracthauda (short accum + A) + -- Runtime Function: unsigned long long accum __satfracthauta (short + accum A) + -- Runtime Function: short fract __satfractsaqq (accum A) + -- Runtime Function: fract __satfractsahq (accum A) + -- Runtime Function: long fract __satfractsasq (accum A) + -- Runtime Function: long long fract __satfractsadq (accum A) + -- Runtime Function: short accum __satfractsaha2 (accum A) + -- Runtime Function: long accum __satfractsada2 (accum A) + -- Runtime Function: long long accum __satfractsata2 (accum A) + -- Runtime Function: unsigned short fract __satfractsauqq (accum A) + -- Runtime Function: unsigned fract __satfractsauhq (accum A) + -- Runtime Function: unsigned long fract __satfractsausq (accum A) + -- Runtime Function: unsigned long long fract __satfractsaudq (accum A) + -- Runtime Function: unsigned short accum __satfractsauha (accum A) + -- Runtime Function: unsigned accum __satfractsausa (accum A) + -- Runtime Function: unsigned long accum __satfractsauda (accum A) + -- Runtime Function: unsigned long long accum __satfractsauta (accum A) + -- Runtime Function: short fract __satfractdaqq (long accum A) + -- Runtime Function: fract __satfractdahq (long accum A) + -- Runtime Function: long fract __satfractdasq (long accum A) + -- Runtime Function: long long fract __satfractdadq (long accum A) + -- Runtime Function: short accum __satfractdaha2 (long accum A) + -- Runtime Function: accum __satfractdasa2 (long accum A) + -- Runtime Function: long long accum __satfractdata2 (long accum A) + -- Runtime Function: unsigned short fract __satfractdauqq (long accum + A) + -- Runtime Function: unsigned fract __satfractdauhq (long accum A) + -- Runtime Function: unsigned long fract __satfractdausq (long accum A) + -- Runtime Function: unsigned long long fract __satfractdaudq (long + accum A) + -- Runtime Function: unsigned short accum __satfractdauha (long accum + A) + -- Runtime Function: unsigned accum __satfractdausa (long accum A) + -- Runtime Function: unsigned long accum __satfractdauda (long accum A) + -- Runtime Function: unsigned long long accum __satfractdauta (long + accum A) + -- Runtime Function: short fract __satfracttaqq (long long accum A) + -- Runtime Function: fract __satfracttahq (long long accum A) + -- Runtime Function: long fract __satfracttasq (long long accum A) + -- Runtime Function: long long fract __satfracttadq (long long accum A) + -- Runtime Function: short accum __satfracttaha2 (long long accum A) + -- Runtime Function: accum __satfracttasa2 (long long accum A) + -- Runtime Function: long accum __satfracttada2 (long long accum A) + -- Runtime Function: unsigned short fract __satfracttauqq (long long + accum A) + -- Runtime Function: unsigned fract __satfracttauhq (long long accum A) + -- Runtime Function: unsigned long fract __satfracttausq (long long + accum A) + -- Runtime Function: unsigned long long fract __satfracttaudq (long + long accum A) + -- Runtime Function: unsigned short accum __satfracttauha (long long + accum A) + -- Runtime Function: unsigned accum __satfracttausa (long long accum A) + -- Runtime Function: unsigned long accum __satfracttauda (long long + accum A) + -- Runtime Function: unsigned long long accum __satfracttauta (long + long accum A) + -- Runtime Function: short fract __satfractuqqqq (unsigned short fract + A) + -- Runtime Function: fract __satfractuqqhq (unsigned short fract A) + -- Runtime Function: long fract __satfractuqqsq (unsigned short fract + A) + -- Runtime Function: long long fract __satfractuqqdq (unsigned short + fract A) + -- Runtime Function: short accum __satfractuqqha (unsigned short fract + A) + -- Runtime Function: accum __satfractuqqsa (unsigned short fract A) + -- Runtime Function: long accum __satfractuqqda (unsigned short fract + A) + -- Runtime Function: long long accum __satfractuqqta (unsigned short + fract A) + -- Runtime Function: unsigned fract __satfractuqquhq2 (unsigned short + fract A) + -- Runtime Function: unsigned long fract __satfractuqqusq2 (unsigned + short fract A) + -- Runtime Function: unsigned long long fract __satfractuqqudq2 + (unsigned short fract A) + -- Runtime Function: unsigned short accum __satfractuqquha (unsigned + short fract A) + -- Runtime Function: unsigned accum __satfractuqqusa (unsigned short + fract A) + -- Runtime Function: unsigned long accum __satfractuqquda (unsigned + short fract A) + -- Runtime Function: unsigned long long accum __satfractuqquta + (unsigned short fract A) + -- Runtime Function: short fract __satfractuhqqq (unsigned fract A) + -- Runtime Function: fract __satfractuhqhq (unsigned fract A) + -- Runtime Function: long fract __satfractuhqsq (unsigned fract A) + -- Runtime Function: long long fract __satfractuhqdq (unsigned fract A) + -- Runtime Function: short accum __satfractuhqha (unsigned fract A) + -- Runtime Function: accum __satfractuhqsa (unsigned fract A) + -- Runtime Function: long accum __satfractuhqda (unsigned fract A) + -- Runtime Function: long long accum __satfractuhqta (unsigned fract A) + -- Runtime Function: unsigned short fract __satfractuhquqq2 (unsigned + fract A) + -- Runtime Function: unsigned long fract __satfractuhqusq2 (unsigned + fract A) + -- Runtime Function: unsigned long long fract __satfractuhqudq2 + (unsigned fract A) + -- Runtime Function: unsigned short accum __satfractuhquha (unsigned + fract A) + -- Runtime Function: unsigned accum __satfractuhqusa (unsigned fract A) + -- Runtime Function: unsigned long accum __satfractuhquda (unsigned + fract A) + -- Runtime Function: unsigned long long accum __satfractuhquta + (unsigned fract A) + -- Runtime Function: short fract __satfractusqqq (unsigned long fract + A) + -- Runtime Function: fract __satfractusqhq (unsigned long fract A) + -- Runtime Function: long fract __satfractusqsq (unsigned long fract A) + -- Runtime Function: long long fract __satfractusqdq (unsigned long + fract A) + -- Runtime Function: short accum __satfractusqha (unsigned long fract + A) + -- Runtime Function: accum __satfractusqsa (unsigned long fract A) + -- Runtime Function: long accum __satfractusqda (unsigned long fract A) + -- Runtime Function: long long accum __satfractusqta (unsigned long + fract A) + -- Runtime Function: unsigned short fract __satfractusquqq2 (unsigned + long fract A) + -- Runtime Function: unsigned fract __satfractusquhq2 (unsigned long + fract A) + -- Runtime Function: unsigned long long fract __satfractusqudq2 + (unsigned long fract A) + -- Runtime Function: unsigned short accum __satfractusquha (unsigned + long fract A) + -- Runtime Function: unsigned accum __satfractusqusa (unsigned long + fract A) + -- Runtime Function: unsigned long accum __satfractusquda (unsigned + long fract A) + -- Runtime Function: unsigned long long accum __satfractusquta + (unsigned long fract A) + -- Runtime Function: short fract __satfractudqqq (unsigned long long + fract A) + -- Runtime Function: fract __satfractudqhq (unsigned long long fract A) + -- Runtime Function: long fract __satfractudqsq (unsigned long long + fract A) + -- Runtime Function: long long fract __satfractudqdq (unsigned long + long fract A) + -- Runtime Function: short accum __satfractudqha (unsigned long long + fract A) + -- Runtime Function: accum __satfractudqsa (unsigned long long fract A) + -- Runtime Function: long accum __satfractudqda (unsigned long long + fract A) + -- Runtime Function: long long accum __satfractudqta (unsigned long + long fract A) + -- Runtime Function: unsigned short fract __satfractudquqq2 (unsigned + long long fract A) + -- Runtime Function: unsigned fract __satfractudquhq2 (unsigned long + long fract A) + -- Runtime Function: unsigned long fract __satfractudqusq2 (unsigned + long long fract A) + -- Runtime Function: unsigned short accum __satfractudquha (unsigned + long long fract A) + -- Runtime Function: unsigned accum __satfractudqusa (unsigned long + long fract A) + -- Runtime Function: unsigned long accum __satfractudquda (unsigned + long long fract A) + -- Runtime Function: unsigned long long accum __satfractudquta + (unsigned long long fract A) + -- Runtime Function: short fract __satfractuhaqq (unsigned short accum + A) + -- Runtime Function: fract __satfractuhahq (unsigned short accum A) + -- Runtime Function: long fract __satfractuhasq (unsigned short accum + A) + -- Runtime Function: long long fract __satfractuhadq (unsigned short + accum A) + -- Runtime Function: short accum __satfractuhaha (unsigned short accum + A) + -- Runtime Function: accum __satfractuhasa (unsigned short accum A) + -- Runtime Function: long accum __satfractuhada (unsigned short accum + A) + -- Runtime Function: long long accum __satfractuhata (unsigned short + accum A) + -- Runtime Function: unsigned short fract __satfractuhauqq (unsigned + short accum A) + -- Runtime Function: unsigned fract __satfractuhauhq (unsigned short + accum A) + -- Runtime Function: unsigned long fract __satfractuhausq (unsigned + short accum A) + -- Runtime Function: unsigned long long fract __satfractuhaudq + (unsigned short accum A) + -- Runtime Function: unsigned accum __satfractuhausa2 (unsigned short + accum A) + -- Runtime Function: unsigned long accum __satfractuhauda2 (unsigned + short accum A) + -- Runtime Function: unsigned long long accum __satfractuhauta2 + (unsigned short accum A) + -- Runtime Function: short fract __satfractusaqq (unsigned accum A) + -- Runtime Function: fract __satfractusahq (unsigned accum A) + -- Runtime Function: long fract __satfractusasq (unsigned accum A) + -- Runtime Function: long long fract __satfractusadq (unsigned accum A) + -- Runtime Function: short accum __satfractusaha (unsigned accum A) + -- Runtime Function: accum __satfractusasa (unsigned accum A) + -- Runtime Function: long accum __satfractusada (unsigned accum A) + -- Runtime Function: long long accum __satfractusata (unsigned accum A) + -- Runtime Function: unsigned short fract __satfractusauqq (unsigned + accum A) + -- Runtime Function: unsigned fract __satfractusauhq (unsigned accum A) + -- Runtime Function: unsigned long fract __satfractusausq (unsigned + accum A) + -- Runtime Function: unsigned long long fract __satfractusaudq + (unsigned accum A) + -- Runtime Function: unsigned short accum __satfractusauha2 (unsigned + accum A) + -- Runtime Function: unsigned long accum __satfractusauda2 (unsigned + accum A) + -- Runtime Function: unsigned long long accum __satfractusauta2 + (unsigned accum A) + -- Runtime Function: short fract __satfractudaqq (unsigned long accum + A) + -- Runtime Function: fract __satfractudahq (unsigned long accum A) + -- Runtime Function: long fract __satfractudasq (unsigned long accum A) + -- Runtime Function: long long fract __satfractudadq (unsigned long + accum A) + -- Runtime Function: short accum __satfractudaha (unsigned long accum + A) + -- Runtime Function: accum __satfractudasa (unsigned long accum A) + -- Runtime Function: long accum __satfractudada (unsigned long accum A) + -- Runtime Function: long long accum __satfractudata (unsigned long + accum A) + -- Runtime Function: unsigned short fract __satfractudauqq (unsigned + long accum A) + -- Runtime Function: unsigned fract __satfractudauhq (unsigned long + accum A) + -- Runtime Function: unsigned long fract __satfractudausq (unsigned + long accum A) + -- Runtime Function: unsigned long long fract __satfractudaudq + (unsigned long accum A) + -- Runtime Function: unsigned short accum __satfractudauha2 (unsigned + long accum A) + -- Runtime Function: unsigned accum __satfractudausa2 (unsigned long + accum A) + -- Runtime Function: unsigned long long accum __satfractudauta2 + (unsigned long accum A) + -- Runtime Function: short fract __satfractutaqq (unsigned long long + accum A) + -- Runtime Function: fract __satfractutahq (unsigned long long accum A) + -- Runtime Function: long fract __satfractutasq (unsigned long long + accum A) + -- Runtime Function: long long fract __satfractutadq (unsigned long + long accum A) + -- Runtime Function: short accum __satfractutaha (unsigned long long + accum A) + -- Runtime Function: accum __satfractutasa (unsigned long long accum A) + -- Runtime Function: long accum __satfractutada (unsigned long long + accum A) + -- Runtime Function: long long accum __satfractutata (unsigned long + long accum A) + -- Runtime Function: unsigned short fract __satfractutauqq (unsigned + long long accum A) + -- Runtime Function: unsigned fract __satfractutauhq (unsigned long + long accum A) + -- Runtime Function: unsigned long fract __satfractutausq (unsigned + long long accum A) + -- Runtime Function: unsigned long long fract __satfractutaudq + (unsigned long long accum A) + -- Runtime Function: unsigned short accum __satfractutauha2 (unsigned + long long accum A) + -- Runtime Function: unsigned accum __satfractutausa2 (unsigned long + long accum A) + -- Runtime Function: unsigned long accum __satfractutauda2 (unsigned + long long accum A) + -- Runtime Function: short fract __satfractqiqq (signed char A) + -- Runtime Function: fract __satfractqihq (signed char A) + -- Runtime Function: long fract __satfractqisq (signed char A) + -- Runtime Function: long long fract __satfractqidq (signed char A) + -- Runtime Function: short accum __satfractqiha (signed char A) + -- Runtime Function: accum __satfractqisa (signed char A) + -- Runtime Function: long accum __satfractqida (signed char A) + -- Runtime Function: long long accum __satfractqita (signed char A) + -- Runtime Function: unsigned short fract __satfractqiuqq (signed char + A) + -- Runtime Function: unsigned fract __satfractqiuhq (signed char A) + -- Runtime Function: unsigned long fract __satfractqiusq (signed char + A) + -- Runtime Function: unsigned long long fract __satfractqiudq (signed + char A) + -- Runtime Function: unsigned short accum __satfractqiuha (signed char + A) + -- Runtime Function: unsigned accum __satfractqiusa (signed char A) + -- Runtime Function: unsigned long accum __satfractqiuda (signed char + A) + -- Runtime Function: unsigned long long accum __satfractqiuta (signed + char A) + -- Runtime Function: short fract __satfracthiqq (short A) + -- Runtime Function: fract __satfracthihq (short A) + -- Runtime Function: long fract __satfracthisq (short A) + -- Runtime Function: long long fract __satfracthidq (short A) + -- Runtime Function: short accum __satfracthiha (short A) + -- Runtime Function: accum __satfracthisa (short A) + -- Runtime Function: long accum __satfracthida (short A) + -- Runtime Function: long long accum __satfracthita (short A) + -- Runtime Function: unsigned short fract __satfracthiuqq (short A) + -- Runtime Function: unsigned fract __satfracthiuhq (short A) + -- Runtime Function: unsigned long fract __satfracthiusq (short A) + -- Runtime Function: unsigned long long fract __satfracthiudq (short A) + -- Runtime Function: unsigned short accum __satfracthiuha (short A) + -- Runtime Function: unsigned accum __satfracthiusa (short A) + -- Runtime Function: unsigned long accum __satfracthiuda (short A) + -- Runtime Function: unsigned long long accum __satfracthiuta (short A) + -- Runtime Function: short fract __satfractsiqq (int A) + -- Runtime Function: fract __satfractsihq (int A) + -- Runtime Function: long fract __satfractsisq (int A) + -- Runtime Function: long long fract __satfractsidq (int A) + -- Runtime Function: short accum __satfractsiha (int A) + -- Runtime Function: accum __satfractsisa (int A) + -- Runtime Function: long accum __satfractsida (int A) + -- Runtime Function: long long accum __satfractsita (int A) + -- Runtime Function: unsigned short fract __satfractsiuqq (int A) + -- Runtime Function: unsigned fract __satfractsiuhq (int A) + -- Runtime Function: unsigned long fract __satfractsiusq (int A) + -- Runtime Function: unsigned long long fract __satfractsiudq (int A) + -- Runtime Function: unsigned short accum __satfractsiuha (int A) + -- Runtime Function: unsigned accum __satfractsiusa (int A) + -- Runtime Function: unsigned long accum __satfractsiuda (int A) + -- Runtime Function: unsigned long long accum __satfractsiuta (int A) + -- Runtime Function: short fract __satfractdiqq (long A) + -- Runtime Function: fract __satfractdihq (long A) + -- Runtime Function: long fract __satfractdisq (long A) + -- Runtime Function: long long fract __satfractdidq (long A) + -- Runtime Function: short accum __satfractdiha (long A) + -- Runtime Function: accum __satfractdisa (long A) + -- Runtime Function: long accum __satfractdida (long A) + -- Runtime Function: long long accum __satfractdita (long A) + -- Runtime Function: unsigned short fract __satfractdiuqq (long A) + -- Runtime Function: unsigned fract __satfractdiuhq (long A) + -- Runtime Function: unsigned long fract __satfractdiusq (long A) + -- Runtime Function: unsigned long long fract __satfractdiudq (long A) + -- Runtime Function: unsigned short accum __satfractdiuha (long A) + -- Runtime Function: unsigned accum __satfractdiusa (long A) + -- Runtime Function: unsigned long accum __satfractdiuda (long A) + -- Runtime Function: unsigned long long accum __satfractdiuta (long A) + -- Runtime Function: short fract __satfracttiqq (long long A) + -- Runtime Function: fract __satfracttihq (long long A) + -- Runtime Function: long fract __satfracttisq (long long A) + -- Runtime Function: long long fract __satfracttidq (long long A) + -- Runtime Function: short accum __satfracttiha (long long A) + -- Runtime Function: accum __satfracttisa (long long A) + -- Runtime Function: long accum __satfracttida (long long A) + -- Runtime Function: long long accum __satfracttita (long long A) + -- Runtime Function: unsigned short fract __satfracttiuqq (long long A) + -- Runtime Function: unsigned fract __satfracttiuhq (long long A) + -- Runtime Function: unsigned long fract __satfracttiusq (long long A) + -- Runtime Function: unsigned long long fract __satfracttiudq (long + long A) + -- Runtime Function: unsigned short accum __satfracttiuha (long long A) + -- Runtime Function: unsigned accum __satfracttiusa (long long A) + -- Runtime Function: unsigned long accum __satfracttiuda (long long A) + -- Runtime Function: unsigned long long accum __satfracttiuta (long + long A) + -- Runtime Function: short fract __satfractsfqq (float A) + -- Runtime Function: fract __satfractsfhq (float A) + -- Runtime Function: long fract __satfractsfsq (float A) + -- Runtime Function: long long fract __satfractsfdq (float A) + -- Runtime Function: short accum __satfractsfha (float A) + -- Runtime Function: accum __satfractsfsa (float A) + -- Runtime Function: long accum __satfractsfda (float A) + -- Runtime Function: long long accum __satfractsfta (float A) + -- Runtime Function: unsigned short fract __satfractsfuqq (float A) + -- Runtime Function: unsigned fract __satfractsfuhq (float A) + -- Runtime Function: unsigned long fract __satfractsfusq (float A) + -- Runtime Function: unsigned long long fract __satfractsfudq (float A) + -- Runtime Function: unsigned short accum __satfractsfuha (float A) + -- Runtime Function: unsigned accum __satfractsfusa (float A) + -- Runtime Function: unsigned long accum __satfractsfuda (float A) + -- Runtime Function: unsigned long long accum __satfractsfuta (float A) + -- Runtime Function: short fract __satfractdfqq (double A) + -- Runtime Function: fract __satfractdfhq (double A) + -- Runtime Function: long fract __satfractdfsq (double A) + -- Runtime Function: long long fract __satfractdfdq (double A) + -- Runtime Function: short accum __satfractdfha (double A) + -- Runtime Function: accum __satfractdfsa (double A) + -- Runtime Function: long accum __satfractdfda (double A) + -- Runtime Function: long long accum __satfractdfta (double A) + -- Runtime Function: unsigned short fract __satfractdfuqq (double A) + -- Runtime Function: unsigned fract __satfractdfuhq (double A) + -- Runtime Function: unsigned long fract __satfractdfusq (double A) + -- Runtime Function: unsigned long long fract __satfractdfudq (double + A) + -- Runtime Function: unsigned short accum __satfractdfuha (double A) + -- Runtime Function: unsigned accum __satfractdfusa (double A) + -- Runtime Function: unsigned long accum __satfractdfuda (double A) + -- Runtime Function: unsigned long long accum __satfractdfuta (double + A) + The functions convert from fractional and signed non-fractionals to + fractionals, with saturation. + + -- Runtime Function: unsigned char __fractunsqqqi (short fract A) + -- Runtime Function: unsigned short __fractunsqqhi (short fract A) + -- Runtime Function: unsigned int __fractunsqqsi (short fract A) + -- Runtime Function: unsigned long __fractunsqqdi (short fract A) + -- Runtime Function: unsigned long long __fractunsqqti (short fract A) + -- Runtime Function: unsigned char __fractunshqqi (fract A) + -- Runtime Function: unsigned short __fractunshqhi (fract A) + -- Runtime Function: unsigned int __fractunshqsi (fract A) + -- Runtime Function: unsigned long __fractunshqdi (fract A) + -- Runtime Function: unsigned long long __fractunshqti (fract A) + -- Runtime Function: unsigned char __fractunssqqi (long fract A) + -- Runtime Function: unsigned short __fractunssqhi (long fract A) + -- Runtime Function: unsigned int __fractunssqsi (long fract A) + -- Runtime Function: unsigned long __fractunssqdi (long fract A) + -- Runtime Function: unsigned long long __fractunssqti (long fract A) + -- Runtime Function: unsigned char __fractunsdqqi (long long fract A) + -- Runtime Function: unsigned short __fractunsdqhi (long long fract A) + -- Runtime Function: unsigned int __fractunsdqsi (long long fract A) + -- Runtime Function: unsigned long __fractunsdqdi (long long fract A) + -- Runtime Function: unsigned long long __fractunsdqti (long long + fract A) + -- Runtime Function: unsigned char __fractunshaqi (short accum A) + -- Runtime Function: unsigned short __fractunshahi (short accum A) + -- Runtime Function: unsigned int __fractunshasi (short accum A) + -- Runtime Function: unsigned long __fractunshadi (short accum A) + -- Runtime Function: unsigned long long __fractunshati (short accum A) + -- Runtime Function: unsigned char __fractunssaqi (accum A) + -- Runtime Function: unsigned short __fractunssahi (accum A) + -- Runtime Function: unsigned int __fractunssasi (accum A) + -- Runtime Function: unsigned long __fractunssadi (accum A) + -- Runtime Function: unsigned long long __fractunssati (accum A) + -- Runtime Function: unsigned char __fractunsdaqi (long accum A) + -- Runtime Function: unsigned short __fractunsdahi (long accum A) + -- Runtime Function: unsigned int __fractunsdasi (long accum A) + -- Runtime Function: unsigned long __fractunsdadi (long accum A) + -- Runtime Function: unsigned long long __fractunsdati (long accum A) + -- Runtime Function: unsigned char __fractunstaqi (long long accum A) + -- Runtime Function: unsigned short __fractunstahi (long long accum A) + -- Runtime Function: unsigned int __fractunstasi (long long accum A) + -- Runtime Function: unsigned long __fractunstadi (long long accum A) + -- Runtime Function: unsigned long long __fractunstati (long long + accum A) + -- Runtime Function: unsigned char __fractunsuqqqi (unsigned short + fract A) + -- Runtime Function: unsigned short __fractunsuqqhi (unsigned short + fract A) + -- Runtime Function: unsigned int __fractunsuqqsi (unsigned short + fract A) + -- Runtime Function: unsigned long __fractunsuqqdi (unsigned short + fract A) + -- Runtime Function: unsigned long long __fractunsuqqti (unsigned + short fract A) + -- Runtime Function: unsigned char __fractunsuhqqi (unsigned fract A) + -- Runtime Function: unsigned short __fractunsuhqhi (unsigned fract A) + -- Runtime Function: unsigned int __fractunsuhqsi (unsigned fract A) + -- Runtime Function: unsigned long __fractunsuhqdi (unsigned fract A) + -- Runtime Function: unsigned long long __fractunsuhqti (unsigned + fract A) + -- Runtime Function: unsigned char __fractunsusqqi (unsigned long + fract A) + -- Runtime Function: unsigned short __fractunsusqhi (unsigned long + fract A) + -- Runtime Function: unsigned int __fractunsusqsi (unsigned long fract + A) + -- Runtime Function: unsigned long __fractunsusqdi (unsigned long + fract A) + -- Runtime Function: unsigned long long __fractunsusqti (unsigned long + fract A) + -- Runtime Function: unsigned char __fractunsudqqi (unsigned long long + fract A) + -- Runtime Function: unsigned short __fractunsudqhi (unsigned long + long fract A) + -- Runtime Function: unsigned int __fractunsudqsi (unsigned long long + fract A) + -- Runtime Function: unsigned long __fractunsudqdi (unsigned long long + fract A) + -- Runtime Function: unsigned long long __fractunsudqti (unsigned long + long fract A) + -- Runtime Function: unsigned char __fractunsuhaqi (unsigned short + accum A) + -- Runtime Function: unsigned short __fractunsuhahi (unsigned short + accum A) + -- Runtime Function: unsigned int __fractunsuhasi (unsigned short + accum A) + -- Runtime Function: unsigned long __fractunsuhadi (unsigned short + accum A) + -- Runtime Function: unsigned long long __fractunsuhati (unsigned + short accum A) + -- Runtime Function: unsigned char __fractunsusaqi (unsigned accum A) + -- Runtime Function: unsigned short __fractunsusahi (unsigned accum A) + -- Runtime Function: unsigned int __fractunsusasi (unsigned accum A) + -- Runtime Function: unsigned long __fractunsusadi (unsigned accum A) + -- Runtime Function: unsigned long long __fractunsusati (unsigned + accum A) + -- Runtime Function: unsigned char __fractunsudaqi (unsigned long + accum A) + -- Runtime Function: unsigned short __fractunsudahi (unsigned long + accum A) + -- Runtime Function: unsigned int __fractunsudasi (unsigned long accum + A) + -- Runtime Function: unsigned long __fractunsudadi (unsigned long + accum A) + -- Runtime Function: unsigned long long __fractunsudati (unsigned long + accum A) + -- Runtime Function: unsigned char __fractunsutaqi (unsigned long long + accum A) + -- Runtime Function: unsigned short __fractunsutahi (unsigned long + long accum A) + -- Runtime Function: unsigned int __fractunsutasi (unsigned long long + accum A) + -- Runtime Function: unsigned long __fractunsutadi (unsigned long long + accum A) + -- Runtime Function: unsigned long long __fractunsutati (unsigned long + long accum A) + -- Runtime Function: short fract __fractunsqiqq (unsigned char A) + -- Runtime Function: fract __fractunsqihq (unsigned char A) + -- Runtime Function: long fract __fractunsqisq (unsigned char A) + -- Runtime Function: long long fract __fractunsqidq (unsigned char A) + -- Runtime Function: short accum __fractunsqiha (unsigned char A) + -- Runtime Function: accum __fractunsqisa (unsigned char A) + -- Runtime Function: long accum __fractunsqida (unsigned char A) + -- Runtime Function: long long accum __fractunsqita (unsigned char A) + -- Runtime Function: unsigned short fract __fractunsqiuqq (unsigned + char A) + -- Runtime Function: unsigned fract __fractunsqiuhq (unsigned char A) + -- Runtime Function: unsigned long fract __fractunsqiusq (unsigned + char A) + -- Runtime Function: unsigned long long fract __fractunsqiudq + (unsigned char A) + -- Runtime Function: unsigned short accum __fractunsqiuha (unsigned + char A) + -- Runtime Function: unsigned accum __fractunsqiusa (unsigned char A) + -- Runtime Function: unsigned long accum __fractunsqiuda (unsigned + char A) + -- Runtime Function: unsigned long long accum __fractunsqiuta + (unsigned char A) + -- Runtime Function: short fract __fractunshiqq (unsigned short A) + -- Runtime Function: fract __fractunshihq (unsigned short A) + -- Runtime Function: long fract __fractunshisq (unsigned short A) + -- Runtime Function: long long fract __fractunshidq (unsigned short A) + -- Runtime Function: short accum __fractunshiha (unsigned short A) + -- Runtime Function: accum __fractunshisa (unsigned short A) + -- Runtime Function: long accum __fractunshida (unsigned short A) + -- Runtime Function: long long accum __fractunshita (unsigned short A) + -- Runtime Function: unsigned short fract __fractunshiuqq (unsigned + short A) + -- Runtime Function: unsigned fract __fractunshiuhq (unsigned short A) + -- Runtime Function: unsigned long fract __fractunshiusq (unsigned + short A) + -- Runtime Function: unsigned long long fract __fractunshiudq + (unsigned short A) + -- Runtime Function: unsigned short accum __fractunshiuha (unsigned + short A) + -- Runtime Function: unsigned accum __fractunshiusa (unsigned short A) + -- Runtime Function: unsigned long accum __fractunshiuda (unsigned + short A) + -- Runtime Function: unsigned long long accum __fractunshiuta + (unsigned short A) + -- Runtime Function: short fract __fractunssiqq (unsigned int A) + -- Runtime Function: fract __fractunssihq (unsigned int A) + -- Runtime Function: long fract __fractunssisq (unsigned int A) + -- Runtime Function: long long fract __fractunssidq (unsigned int A) + -- Runtime Function: short accum __fractunssiha (unsigned int A) + -- Runtime Function: accum __fractunssisa (unsigned int A) + -- Runtime Function: long accum __fractunssida (unsigned int A) + -- Runtime Function: long long accum __fractunssita (unsigned int A) + -- Runtime Function: unsigned short fract __fractunssiuqq (unsigned + int A) + -- Runtime Function: unsigned fract __fractunssiuhq (unsigned int A) + -- Runtime Function: unsigned long fract __fractunssiusq (unsigned int + A) + -- Runtime Function: unsigned long long fract __fractunssiudq + (unsigned int A) + -- Runtime Function: unsigned short accum __fractunssiuha (unsigned + int A) + -- Runtime Function: unsigned accum __fractunssiusa (unsigned int A) + -- Runtime Function: unsigned long accum __fractunssiuda (unsigned int + A) + -- Runtime Function: unsigned long long accum __fractunssiuta + (unsigned int A) + -- Runtime Function: short fract __fractunsdiqq (unsigned long A) + -- Runtime Function: fract __fractunsdihq (unsigned long A) + -- Runtime Function: long fract __fractunsdisq (unsigned long A) + -- Runtime Function: long long fract __fractunsdidq (unsigned long A) + -- Runtime Function: short accum __fractunsdiha (unsigned long A) + -- Runtime Function: accum __fractunsdisa (unsigned long A) + -- Runtime Function: long accum __fractunsdida (unsigned long A) + -- Runtime Function: long long accum __fractunsdita (unsigned long A) + -- Runtime Function: unsigned short fract __fractunsdiuqq (unsigned + long A) + -- Runtime Function: unsigned fract __fractunsdiuhq (unsigned long A) + -- Runtime Function: unsigned long fract __fractunsdiusq (unsigned + long A) + -- Runtime Function: unsigned long long fract __fractunsdiudq + (unsigned long A) + -- Runtime Function: unsigned short accum __fractunsdiuha (unsigned + long A) + -- Runtime Function: unsigned accum __fractunsdiusa (unsigned long A) + -- Runtime Function: unsigned long accum __fractunsdiuda (unsigned + long A) + -- Runtime Function: unsigned long long accum __fractunsdiuta + (unsigned long A) + -- Runtime Function: short fract __fractunstiqq (unsigned long long A) + -- Runtime Function: fract __fractunstihq (unsigned long long A) + -- Runtime Function: long fract __fractunstisq (unsigned long long A) + -- Runtime Function: long long fract __fractunstidq (unsigned long + long A) + -- Runtime Function: short accum __fractunstiha (unsigned long long A) + -- Runtime Function: accum __fractunstisa (unsigned long long A) + -- Runtime Function: long accum __fractunstida (unsigned long long A) + -- Runtime Function: long long accum __fractunstita (unsigned long + long A) + -- Runtime Function: unsigned short fract __fractunstiuqq (unsigned + long long A) + -- Runtime Function: unsigned fract __fractunstiuhq (unsigned long + long A) + -- Runtime Function: unsigned long fract __fractunstiusq (unsigned + long long A) + -- Runtime Function: unsigned long long fract __fractunstiudq + (unsigned long long A) + -- Runtime Function: unsigned short accum __fractunstiuha (unsigned + long long A) + -- Runtime Function: unsigned accum __fractunstiusa (unsigned long + long A) + -- Runtime Function: unsigned long accum __fractunstiuda (unsigned + long long A) + -- Runtime Function: unsigned long long accum __fractunstiuta + (unsigned long long A) + These functions convert from fractionals to unsigned + non-fractionals; and from unsigned non-fractionals to fractionals, + without saturation. + + -- Runtime Function: short fract __satfractunsqiqq (unsigned char A) + -- Runtime Function: fract __satfractunsqihq (unsigned char A) + -- Runtime Function: long fract __satfractunsqisq (unsigned char A) + -- Runtime Function: long long fract __satfractunsqidq (unsigned char + A) + -- Runtime Function: short accum __satfractunsqiha (unsigned char A) + -- Runtime Function: accum __satfractunsqisa (unsigned char A) + -- Runtime Function: long accum __satfractunsqida (unsigned char A) + -- Runtime Function: long long accum __satfractunsqita (unsigned char + A) + -- Runtime Function: unsigned short fract __satfractunsqiuqq (unsigned + char A) + -- Runtime Function: unsigned fract __satfractunsqiuhq (unsigned char + A) + -- Runtime Function: unsigned long fract __satfractunsqiusq (unsigned + char A) + -- Runtime Function: unsigned long long fract __satfractunsqiudq + (unsigned char A) + -- Runtime Function: unsigned short accum __satfractunsqiuha (unsigned + char A) + -- Runtime Function: unsigned accum __satfractunsqiusa (unsigned char + A) + -- Runtime Function: unsigned long accum __satfractunsqiuda (unsigned + char A) + -- Runtime Function: unsigned long long accum __satfractunsqiuta + (unsigned char A) + -- Runtime Function: short fract __satfractunshiqq (unsigned short A) + -- Runtime Function: fract __satfractunshihq (unsigned short A) + -- Runtime Function: long fract __satfractunshisq (unsigned short A) + -- Runtime Function: long long fract __satfractunshidq (unsigned short + A) + -- Runtime Function: short accum __satfractunshiha (unsigned short A) + -- Runtime Function: accum __satfractunshisa (unsigned short A) + -- Runtime Function: long accum __satfractunshida (unsigned short A) + -- Runtime Function: long long accum __satfractunshita (unsigned short + A) + -- Runtime Function: unsigned short fract __satfractunshiuqq (unsigned + short A) + -- Runtime Function: unsigned fract __satfractunshiuhq (unsigned short + A) + -- Runtime Function: unsigned long fract __satfractunshiusq (unsigned + short A) + -- Runtime Function: unsigned long long fract __satfractunshiudq + (unsigned short A) + -- Runtime Function: unsigned short accum __satfractunshiuha (unsigned + short A) + -- Runtime Function: unsigned accum __satfractunshiusa (unsigned short + A) + -- Runtime Function: unsigned long accum __satfractunshiuda (unsigned + short A) + -- Runtime Function: unsigned long long accum __satfractunshiuta + (unsigned short A) + -- Runtime Function: short fract __satfractunssiqq (unsigned int A) + -- Runtime Function: fract __satfractunssihq (unsigned int A) + -- Runtime Function: long fract __satfractunssisq (unsigned int A) + -- Runtime Function: long long fract __satfractunssidq (unsigned int A) + -- Runtime Function: short accum __satfractunssiha (unsigned int A) + -- Runtime Function: accum __satfractunssisa (unsigned int A) + -- Runtime Function: long accum __satfractunssida (unsigned int A) + -- Runtime Function: long long accum __satfractunssita (unsigned int A) + -- Runtime Function: unsigned short fract __satfractunssiuqq (unsigned + int A) + -- Runtime Function: unsigned fract __satfractunssiuhq (unsigned int A) + -- Runtime Function: unsigned long fract __satfractunssiusq (unsigned + int A) + -- Runtime Function: unsigned long long fract __satfractunssiudq + (unsigned int A) + -- Runtime Function: unsigned short accum __satfractunssiuha (unsigned + int A) + -- Runtime Function: unsigned accum __satfractunssiusa (unsigned int A) + -- Runtime Function: unsigned long accum __satfractunssiuda (unsigned + int A) + -- Runtime Function: unsigned long long accum __satfractunssiuta + (unsigned int A) + -- Runtime Function: short fract __satfractunsdiqq (unsigned long A) + -- Runtime Function: fract __satfractunsdihq (unsigned long A) + -- Runtime Function: long fract __satfractunsdisq (unsigned long A) + -- Runtime Function: long long fract __satfractunsdidq (unsigned long + A) + -- Runtime Function: short accum __satfractunsdiha (unsigned long A) + -- Runtime Function: accum __satfractunsdisa (unsigned long A) + -- Runtime Function: long accum __satfractunsdida (unsigned long A) + -- Runtime Function: long long accum __satfractunsdita (unsigned long + A) + -- Runtime Function: unsigned short fract __satfractunsdiuqq (unsigned + long A) + -- Runtime Function: unsigned fract __satfractunsdiuhq (unsigned long + A) + -- Runtime Function: unsigned long fract __satfractunsdiusq (unsigned + long A) + -- Runtime Function: unsigned long long fract __satfractunsdiudq + (unsigned long A) + -- Runtime Function: unsigned short accum __satfractunsdiuha (unsigned + long A) + -- Runtime Function: unsigned accum __satfractunsdiusa (unsigned long + A) + -- Runtime Function: unsigned long accum __satfractunsdiuda (unsigned + long A) + -- Runtime Function: unsigned long long accum __satfractunsdiuta + (unsigned long A) + -- Runtime Function: short fract __satfractunstiqq (unsigned long long + A) + -- Runtime Function: fract __satfractunstihq (unsigned long long A) + -- Runtime Function: long fract __satfractunstisq (unsigned long long + A) + -- Runtime Function: long long fract __satfractunstidq (unsigned long + long A) + -- Runtime Function: short accum __satfractunstiha (unsigned long long + A) + -- Runtime Function: accum __satfractunstisa (unsigned long long A) + -- Runtime Function: long accum __satfractunstida (unsigned long long + A) + -- Runtime Function: long long accum __satfractunstita (unsigned long + long A) + -- Runtime Function: unsigned short fract __satfractunstiuqq (unsigned + long long A) + -- Runtime Function: unsigned fract __satfractunstiuhq (unsigned long + long A) + -- Runtime Function: unsigned long fract __satfractunstiusq (unsigned + long long A) + -- Runtime Function: unsigned long long fract __satfractunstiudq + (unsigned long long A) + -- Runtime Function: unsigned short accum __satfractunstiuha (unsigned + long long A) + -- Runtime Function: unsigned accum __satfractunstiusa (unsigned long + long A) + -- Runtime Function: unsigned long accum __satfractunstiuda (unsigned + long long A) + -- Runtime Function: unsigned long long accum __satfractunstiuta + (unsigned long long A) + These functions convert from unsigned non-fractionals to + fractionals, with saturation. + + +File: gccint.info, Node: Exception handling routines, Next: Miscellaneous routines, Prev: Fixed-point fractional library routines, Up: Libgcc + +4.5 Language-independent routines for exception handling +======================================================== + +document me! + + _Unwind_DeleteException + _Unwind_Find_FDE + _Unwind_ForcedUnwind + _Unwind_GetGR + _Unwind_GetIP + _Unwind_GetLanguageSpecificData + _Unwind_GetRegionStart + _Unwind_GetTextRelBase + _Unwind_GetDataRelBase + _Unwind_RaiseException + _Unwind_Resume + _Unwind_SetGR + _Unwind_SetIP + _Unwind_FindEnclosingFunction + _Unwind_SjLj_Register + _Unwind_SjLj_Unregister + _Unwind_SjLj_RaiseException + _Unwind_SjLj_ForcedUnwind + _Unwind_SjLj_Resume + __deregister_frame + __deregister_frame_info + __deregister_frame_info_bases + __register_frame + __register_frame_info + __register_frame_info_bases + __register_frame_info_table + __register_frame_info_table_bases + __register_frame_table + + +File: gccint.info, Node: Miscellaneous routines, Prev: Exception handling routines, Up: Libgcc + +4.6 Miscellaneous runtime library routines +========================================== + +4.6.1 Cache control functions +----------------------------- + + -- Runtime Function: void __clear_cache (char *BEG, char *END) + This function clears the instruction cache between BEG and END. + +4.6.2 Split stack functions and variables +----------------------------------------- + + -- Runtime Function: void * __splitstack_find (void *SEGMENT_ARG, void + *SP, size_t LEN, void **NEXT_SEGMENT, void **NEXT_SP, void + **INITIAL_SP) + When using `-fsplit-stack', this call may be used to iterate over + the stack segments. It may be called like this: + void *next_segment = NULL; + void *next_sp = NULL; + void *initial_sp = NULL; + void *stack; + size_t stack_size; + while ((stack = __splitstack_find (next_segment, next_sp, + &stack_size, &next_segment, + &next_sp, &initial_sp)) + != NULL) + { + /* Stack segment starts at stack and is + stack_size bytes long. */ + } + + There is no way to iterate over the stack segments of a different + thread. However, what is permitted is for one thread to call this + with the SEGMENT_ARG and SP arguments NULL, to pass NEXT_SEGMENT, + NEXT_SP, and INITIAL_SP to a different thread, and then to suspend + one way or another. A different thread may run the subsequent + `__splitstack_find' iterations. Of course, this will only work if + the first thread is suspended while the second thread is calling + `__splitstack_find'. If not, the second thread could be looking + at the stack while it is changing, and anything could happen. + + -- Variable: __morestack_segments + -- Variable: __morestack_current_segment + -- Variable: __morestack_initial_sp + Internal variables used by the `-fsplit-stack' implementation. + + +File: gccint.info, Node: Languages, Next: Source Tree, Prev: Libgcc, Up: Top + +5 Language Front Ends in GCC +**************************** + +The interface to front ends for languages in GCC, and in particular the +`tree' structure (*note GENERIC::), was initially designed for C, and +many aspects of it are still somewhat biased towards C and C-like +languages. It is, however, reasonably well suited to other procedural +languages, and front ends for many such languages have been written for +GCC. + + Writing a compiler as a front end for GCC, rather than compiling +directly to assembler or generating C code which is then compiled by +GCC, has several advantages: + + * GCC front ends benefit from the support for many different target + machines already present in GCC. + + * GCC front ends benefit from all the optimizations in GCC. Some of + these, such as alias analysis, may work better when GCC is + compiling directly from source code then when it is compiling from + generated C code. + + * Better debugging information is generated when compiling directly + from source code than when going via intermediate generated C code. + + Because of the advantages of writing a compiler as a GCC front end, +GCC front ends have also been created for languages very different from +those for which GCC was designed, such as the declarative +logic/functional language Mercury. For these reasons, it may also be +useful to implement compilers created for specialized purposes (for +example, as part of a research project) as GCC front ends. + + +File: gccint.info, Node: Source Tree, Next: Testsuites, Prev: Languages, Up: Top + +6 Source Tree Structure and Build System +**************************************** + +This chapter describes the structure of the GCC source tree, and how +GCC is built. The user documentation for building and installing GCC +is in a separate manual (`http://gcc.gnu.org/install/'), with which it +is presumed that you are familiar. + +* Menu: + +* Configure Terms:: Configuration terminology and history. +* Top Level:: The top level source directory. +* gcc Directory:: The `gcc' subdirectory. + + +File: gccint.info, Node: Configure Terms, Next: Top Level, Up: Source Tree + +6.1 Configure Terms and History +=============================== + +The configure and build process has a long and colorful history, and can +be confusing to anyone who doesn't know why things are the way they are. +While there are other documents which describe the configuration process +in detail, here are a few things that everyone working on GCC should +know. + + There are three system names that the build knows about: the machine +you are building on ("build"), the machine that you are building for +("host"), and the machine that GCC will produce code for ("target"). +When you configure GCC, you specify these with `--build=', `--host=', +and `--target='. + + Specifying the host without specifying the build should be avoided, as +`configure' may (and once did) assume that the host you specify is also +the build, which may not be true. + + If build, host, and target are all the same, this is called a +"native". If build and host are the same but target is different, this +is called a "cross". If build, host, and target are all different this +is called a "canadian" (for obscure reasons dealing with Canada's +political party and the background of the person working on the build +at that time). If host and target are the same, but build is +different, you are using a cross-compiler to build a native for a +different system. Some people call this a "host-x-host", "crossed +native", or "cross-built native". If build and target are the same, +but host is different, you are using a cross compiler to build a cross +compiler that produces code for the machine you're building on. This +is rare, so there is no common way of describing it. There is a +proposal to call this a "crossback". + + If build and host are the same, the GCC you are building will also be +used to build the target libraries (like `libstdc++'). If build and +host are different, you must have already built and installed a cross +compiler that will be used to build the target libraries (if you +configured with `--target=foo-bar', this compiler will be called +`foo-bar-gcc'). + + In the case of target libraries, the machine you're building for is the +machine you specified with `--target'. So, build is the machine you're +building on (no change there), host is the machine you're building for +(the target libraries are built for the target, so host is the target +you specified), and target doesn't apply (because you're not building a +compiler, you're building libraries). The configure/make process will +adjust these variables as needed. It also sets `$with_cross_host' to +the original `--host' value in case you need it. + + The `libiberty' support library is built up to three times: once for +the host, once for the target (even if they are the same), and once for +the build if build and host are different. This allows it to be used +by all programs which are generated in the course of the build process. + + +File: gccint.info, Node: Top Level, Next: gcc Directory, Prev: Configure Terms, Up: Source Tree + +6.2 Top Level Source Directory +============================== + +The top level source directory in a GCC distribution contains several +files and directories that are shared with other software distributions +such as that of GNU Binutils. It also contains several subdirectories +that contain parts of GCC and its runtime libraries: + +`boehm-gc' + The Boehm conservative garbage collector, used as part of the Java + runtime library. + +`config' + Autoconf macros and Makefile fragments used throughout the tree. + +`contrib' + Contributed scripts that may be found useful in conjunction with + GCC. One of these, `contrib/texi2pod.pl', is used to generate man + pages from Texinfo manuals as part of the GCC build process. + +`fixincludes' + The support for fixing system headers to work with GCC. See + `fixincludes/README' for more information. The headers fixed by + this mechanism are installed in `LIBSUBDIR/include-fixed'. Along + with those headers, `README-fixinc' is also installed, as + `LIBSUBDIR/include-fixed/README'. + +`gcc' + The main sources of GCC itself (except for runtime libraries), + including optimizers, support for different target architectures, + language front ends, and testsuites. *Note The `gcc' + Subdirectory: gcc Directory, for details. + +`gnattools' + Support tools for GNAT. + +`include' + Headers for the `libiberty' library. + +`intl' + GNU `libintl', from GNU `gettext', for systems which do not + include it in `libc'. + +`libada' + The Ada runtime library. + +`libcpp' + The C preprocessor library. + +`libdecnumber' + The Decimal Float support library. + +`libffi' + The `libffi' library, used as part of the Java runtime library. + +`libgcc' + The GCC runtime library. + +`libgfortran' + The Fortran runtime library. + +`libgo' + The Go runtime library. The bulk of this library is mirrored from + the master Go repository (http://code.google.com/p/go/). + +`libgomp' + The GNU OpenMP runtime library. + +`libiberty' + The `libiberty' library, used for portability and for some + generally useful data structures and algorithms. *Note + Introduction: (libiberty)Top, for more information about this + library. + +`libjava' + The Java runtime library. + +`libmudflap' + The `libmudflap' library, used for instrumenting pointer and array + dereferencing operations. + +`libobjc' + The Objective-C and Objective-C++ runtime library. + +`libssp' + The Stack protector runtime library. + +`libstdc++-v3' + The C++ runtime library. + +`lto-plugin' + Plugin used by `gold' if link-time optimizations are enabled. + +`maintainer-scripts' + Scripts used by the `gccadmin' account on `gcc.gnu.org'. + +`zlib' + The `zlib' compression library, used by the Java front end, as + part of the Java runtime library, and for compressing and + uncompressing GCC's intermediate language in LTO object files. + + The build system in the top level directory, including how recursion +into subdirectories works and how building runtime libraries for +multilibs is handled, is documented in a separate manual, included with +GNU Binutils. *Note GNU configure and build system: (configure)Top, +for details. + + +File: gccint.info, Node: gcc Directory, Prev: Top Level, Up: Source Tree + +6.3 The `gcc' Subdirectory +========================== + +The `gcc' directory contains many files that are part of the C sources +of GCC, other files used as part of the configuration and build +process, and subdirectories including documentation and a testsuite. +The files that are sources of GCC are documented in a separate chapter. +*Note Passes and Files of the Compiler: Passes. + +* Menu: + +* Subdirectories:: Subdirectories of `gcc'. +* Configuration:: The configuration process, and the files it uses. +* Build:: The build system in the `gcc' directory. +* Makefile:: Targets in `gcc/Makefile'. +* Library Files:: Library source files and headers under `gcc/'. +* Headers:: Headers installed by GCC. +* Documentation:: Building documentation in GCC. +* Front End:: Anatomy of a language front end. +* Back End:: Anatomy of a target back end. + + +File: gccint.info, Node: Subdirectories, Next: Configuration, Up: gcc Directory + +6.3.1 Subdirectories of `gcc' +----------------------------- + +The `gcc' directory contains the following subdirectories: + +`LANGUAGE' + Subdirectories for various languages. Directories containing a + file `config-lang.in' are language subdirectories. The contents of + the subdirectories `cp' (for C++), `lto' (for LTO), `objc' (for + Objective-C) and `objcp' (for Objective-C++) are documented in + this manual (*note Passes and Files of the Compiler: Passes.); + those for other languages are not. *Note Anatomy of a Language + Front End: Front End, for details of the files in these + directories. + +`config' + Configuration files for supported architectures and operating + systems. *Note Anatomy of a Target Back End: Back End, for + details of the files in this directory. + +`doc' + Texinfo documentation for GCC, together with automatically + generated man pages and support for converting the installation + manual to HTML. *Note Documentation::. + +`ginclude' + System headers installed by GCC, mainly those required by the C + standard of freestanding implementations. *Note Headers Installed + by GCC: Headers, for details of when these and other headers are + installed. + +`po' + Message catalogs with translations of messages produced by GCC into + various languages, `LANGUAGE.po'. This directory also contains + `gcc.pot', the template for these message catalogues, `exgettext', + a wrapper around `gettext' to extract the messages from the GCC + sources and create `gcc.pot', which is run by `make gcc.pot', and + `EXCLUDES', a list of files from which messages should not be + extracted. + +`testsuite' + The GCC testsuites (except for those for runtime libraries). + *Note Testsuites::. + + +File: gccint.info, Node: Configuration, Next: Build, Prev: Subdirectories, Up: gcc Directory + +6.3.2 Configuration in the `gcc' Directory +------------------------------------------ + +The `gcc' directory is configured with an Autoconf-generated script +`configure'. The `configure' script is generated from `configure.ac' +and `aclocal.m4'. From the files `configure.ac' and `acconfig.h', +Autoheader generates the file `config.in'. The file `cstamp-h.in' is +used as a timestamp. + +* Menu: + +* Config Fragments:: Scripts used by `configure'. +* System Config:: The `config.build', `config.host', and + `config.gcc' files. +* Configuration Files:: Files created by running `configure'. + + +File: gccint.info, Node: Config Fragments, Next: System Config, Up: Configuration + +6.3.2.1 Scripts Used by `configure' +................................... + +`configure' uses some other scripts to help in its work: + + * The standard GNU `config.sub' and `config.guess' files, kept in + the top level directory, are used. + + * The file `config.gcc' is used to handle configuration specific to + the particular target machine. The file `config.build' is used to + handle configuration specific to the particular build machine. + The file `config.host' is used to handle configuration specific to + the particular host machine. (In general, these should only be + used for features that cannot reasonably be tested in Autoconf + feature tests.) *Note The `config.build'; `config.host'; and + `config.gcc' Files: System Config, for details of the contents of + these files. + + * Each language subdirectory has a file `LANGUAGE/config-lang.in' + that is used for front-end-specific configuration. *Note The + Front End `config-lang.in' File: Front End Config, for details of + this file. + + * A helper script `configure.frag' is used as part of creating the + output of `configure'. + + +File: gccint.info, Node: System Config, Next: Configuration Files, Prev: Config Fragments, Up: Configuration + +6.3.2.2 The `config.build'; `config.host'; and `config.gcc' Files +................................................................. + +The `config.build' file contains specific rules for particular systems +which GCC is built on. This should be used as rarely as possible, as +the behavior of the build system can always be detected by autoconf. + + The `config.host' file contains specific rules for particular systems +which GCC will run on. This is rarely needed. + + The `config.gcc' file contains specific rules for particular systems +which GCC will generate code for. This is usually needed. + + Each file has a list of the shell variables it sets, with +descriptions, at the top of the file. + + FIXME: document the contents of these files, and what variables should +be set to control build, host and target configuration. + + +File: gccint.info, Node: Configuration Files, Prev: System Config, Up: Configuration + +6.3.2.3 Files Created by `configure' +.................................... + +Here we spell out what files will be set up by `configure' in the `gcc' +directory. Some other files are created as temporary files in the +configuration process, and are not used in the subsequent build; these +are not documented. + + * `Makefile' is constructed from `Makefile.in', together with the + host and target fragments (*note Makefile Fragments: Fragments.) + `t-TARGET' and `x-HOST' from `config', if any, and language + Makefile fragments `LANGUAGE/Make-lang.in'. + + * `auto-host.h' contains information about the host machine + determined by `configure'. If the host machine is different from + the build machine, then `auto-build.h' is also created, containing + such information about the build machine. + + * `config.status' is a script that may be run to recreate the + current configuration. + + * `configargs.h' is a header containing details of the arguments + passed to `configure' to configure GCC, and of the thread model + used. + + * `cstamp-h' is used as a timestamp. + + * If a language `config-lang.in' file (*note The Front End + `config-lang.in' File: Front End Config.) sets `outputs', then the + files listed in `outputs' there are also generated. + + The following configuration headers are created from the Makefile, +using `mkconfig.sh', rather than directly by `configure'. `config.h', +`bconfig.h' and `tconfig.h' all contain the `xm-MACHINE.h' header, if +any, appropriate to the host, build and target machines respectively, +the configuration headers for the target, and some definitions; for the +host and build machines, these include the autoconfigured headers +generated by `configure'. The other configuration headers are +determined by `config.gcc'. They also contain the typedefs for `rtx', +`rtvec' and `tree'. + + * `config.h', for use in programs that run on the host machine. + + * `bconfig.h', for use in programs that run on the build machine. + + * `tconfig.h', for use in programs and libraries for the target + machine. + + * `tm_p.h', which includes the header `MACHINE-protos.h' that + contains prototypes for functions in the target `.c' file. FIXME: + why is such a separate header necessary? + + +File: gccint.info, Node: Build, Next: Makefile, Prev: Configuration, Up: gcc Directory + +6.3.3 Build System in the `gcc' Directory +----------------------------------------- + +FIXME: describe the build system, including what is built in what +stages. Also list the various source files that are used in the build +process but aren't source files of GCC itself and so aren't documented +below (*note Passes::). + + +File: gccint.info, Node: Makefile, Next: Library Files, Prev: Build, Up: gcc Directory + +6.3.4 Makefile Targets +---------------------- + +These targets are available from the `gcc' directory: + +`all' + This is the default target. Depending on what your + build/host/target configuration is, it coordinates all the things + that need to be built. + +`doc' + Produce info-formatted documentation and man pages. Essentially it + calls `make man' and `make info'. + +`dvi' + Produce DVI-formatted documentation. + +`pdf' + Produce PDF-formatted documentation. + +`html' + Produce HTML-formatted documentation. + +`man' + Generate man pages. + +`info' + Generate info-formatted pages. + +`mostlyclean' + Delete the files made while building the compiler. + +`clean' + That, and all the other files built by `make all'. + +`distclean' + That, and all the files created by `configure'. + +`maintainer-clean' + Distclean plus any file that can be generated from other files. + Note that additional tools may be required beyond what is normally + needed to build GCC. + +`srcextra' + Generates files in the source directory that are not + version-controlled but should go into a release tarball. + +`srcinfo' +`srcman' + Copies the info-formatted and manpage documentation into the source + directory usually for the purpose of generating a release tarball. + +`install' + Installs GCC. + +`uninstall' + Deletes installed files, though this is not supported. + +`check' + Run the testsuite. This creates a `testsuite' subdirectory that + has various `.sum' and `.log' files containing the results of the + testing. You can run subsets with, for example, `make check-gcc'. + You can specify specific tests by setting `RUNTESTFLAGS' to be the + name of the `.exp' file, optionally followed by (for some tests) + an equals and a file wildcard, like: + + make check-gcc RUNTESTFLAGS="execute.exp=19980413-*" + + Note that running the testsuite may require additional tools be + installed, such as Tcl or DejaGnu. + + The toplevel tree from which you start GCC compilation is not the GCC +directory, but rather a complex Makefile that coordinates the various +steps of the build, including bootstrapping the compiler and using the +new compiler to build target libraries. + + When GCC is configured for a native configuration, the default action +for `make' is to do a full three-stage bootstrap. This means that GCC +is built three times--once with the native compiler, once with the +native-built compiler it just built, and once with the compiler it +built the second time. In theory, the last two should produce the same +results, which `make compare' can check. Each stage is configured +separately and compiled into a separate directory, to minimize problems +due to ABI incompatibilities between the native compiler and GCC. + + If you do a change, rebuilding will also start from the first stage +and "bubble" up the change through the three stages. Each stage is +taken from its build directory (if it had been built previously), +rebuilt, and copied to its subdirectory. This will allow you to, for +example, continue a bootstrap after fixing a bug which causes the +stage2 build to crash. It does not provide as good coverage of the +compiler as bootstrapping from scratch, but it ensures that the new +code is syntactically correct (e.g., that you did not use GCC extensions +by mistake), and avoids spurious bootstrap comparison failures(1). + + Other targets available from the top level include: + +`bootstrap-lean' + Like `bootstrap', except that the various stages are removed once + they're no longer needed. This saves disk space. + +`bootstrap2' +`bootstrap2-lean' + Performs only the first two stages of bootstrap. Unlike a + three-stage bootstrap, this does not perform a comparison to test + that the compiler is running properly. Note that the disk space + required by a "lean" bootstrap is approximately independent of the + number of stages. + +`stageN-bubble (N = 1...4, profile, feedback)' + Rebuild all the stages up to N, with the appropriate flags, + "bubbling" the changes as described above. + +`all-stageN (N = 1...4, profile, feedback)' + Assuming that stage N has already been built, rebuild it with the + appropriate flags. This is rarely needed. + +`cleanstrap' + Remove everything (`make clean') and rebuilds (`make bootstrap'). + +`compare' + Compares the results of stages 2 and 3. This ensures that the + compiler is running properly, since it should produce the same + object files regardless of how it itself was compiled. + +`profiledbootstrap' + Builds a compiler with profiling feedback information. In this + case, the second and third stages are named `profile' and + `feedback', respectively. For more information, see *note + Building with profile feedback: (gccinstall)Building. + +`restrap' + Restart a bootstrap, so that everything that was not built with + the system compiler is rebuilt. + +`stageN-start (N = 1...4, profile, feedback)' + For each package that is bootstrapped, rename directories so that, + for example, `gcc' points to the stageN GCC, compiled with the + stageN-1 GCC(2). + + You will invoke this target if you need to test or debug the + stageN GCC. If you only need to execute GCC (but you need not run + `make' either to rebuild it or to run test suites), you should be + able to work directly in the `stageN-gcc' directory. This makes + it easier to debug multiple stages in parallel. + +`stage' + For each package that is bootstrapped, relocate its build directory + to indicate its stage. For example, if the `gcc' directory points + to the stage2 GCC, after invoking this target it will be renamed + to `stage2-gcc'. + + + If you wish to use non-default GCC flags when compiling the stage2 and +stage3 compilers, set `BOOT_CFLAGS' on the command line when doing +`make'. + + Usually, the first stage only builds the languages that the compiler +is written in: typically, C and maybe Ada. If you are debugging a +miscompilation of a different stage2 front-end (for example, of the +Fortran front-end), you may want to have front-ends for other languages +in the first stage as well. To do so, set `STAGE1_LANGUAGES' on the +command line when doing `make'. + + For example, in the aforementioned scenario of debugging a Fortran +front-end miscompilation caused by the stage1 compiler, you may need a +command like + + make stage2-bubble STAGE1_LANGUAGES=c,fortran + + Alternatively, you can use per-language targets to build and test +languages that are not enabled by default in stage1. For example, +`make f951' will build a Fortran compiler even in the stage1 build +directory. + + ---------- Footnotes ---------- + + (1) Except if the compiler was buggy and miscompiled some of the files +that were not modified. In this case, it's best to use `make restrap'. + + (2) Customarily, the system compiler is also termed the `stage0' GCC. + + +File: gccint.info, Node: Library Files, Next: Headers, Prev: Makefile, Up: gcc Directory + +6.3.5 Library Source Files and Headers under the `gcc' Directory +---------------------------------------------------------------- + +FIXME: list here, with explanation, all the C source files and headers +under the `gcc' directory that aren't built into the GCC executable but +rather are part of runtime libraries and object files, such as +`crtstuff.c' and `unwind-dw2.c'. *Note Headers Installed by GCC: +Headers, for more information about the `ginclude' directory. + + +File: gccint.info, Node: Headers, Next: Documentation, Prev: Library Files, Up: gcc Directory + +6.3.6 Headers Installed by GCC +------------------------------ + +In general, GCC expects the system C library to provide most of the +headers to be used with it. However, GCC will fix those headers if +necessary to make them work with GCC, and will install some headers +required of freestanding implementations. These headers are installed +in `LIBSUBDIR/include'. Headers for non-C runtime libraries are also +installed by GCC; these are not documented here. (FIXME: document them +somewhere.) + + Several of the headers GCC installs are in the `ginclude' directory. +These headers, `iso646.h', `stdarg.h', `stdbool.h', and `stddef.h', are +installed in `LIBSUBDIR/include', unless the target Makefile fragment +(*note Target Fragment::) overrides this by setting `USER_H'. + + In addition to these headers and those generated by fixing system +headers to work with GCC, some other headers may also be installed in +`LIBSUBDIR/include'. `config.gcc' may set `extra_headers'; this +specifies additional headers under `config' to be installed on some +systems. + + GCC installs its own version of `<float.h>', from `ginclude/float.h'. +This is done to cope with command-line options that change the +representation of floating point numbers. + + GCC also installs its own version of `<limits.h>'; this is generated +from `glimits.h', together with `limitx.h' and `limity.h' if the system +also has its own version of `<limits.h>'. (GCC provides its own header +because it is required of ISO C freestanding implementations, but needs +to include the system header from its own header as well because other +standards such as POSIX specify additional values to be defined in +`<limits.h>'.) The system's `<limits.h>' header is used via +`LIBSUBDIR/include/syslimits.h', which is copied from `gsyslimits.h' if +it does not need fixing to work with GCC; if it needs fixing, +`syslimits.h' is the fixed copy. + + GCC can also install `<tgmath.h>'. It will do this when `config.gcc' +sets `use_gcc_tgmath' to `yes'. + + +File: gccint.info, Node: Documentation, Next: Front End, Prev: Headers, Up: gcc Directory + +6.3.7 Building Documentation +---------------------------- + +The main GCC documentation is in the form of manuals in Texinfo format. +These are installed in Info format; DVI versions may be generated by +`make dvi', PDF versions by `make pdf', and HTML versions by `make +html'. In addition, some man pages are generated from the Texinfo +manuals, there are some other text files with miscellaneous +documentation, and runtime libraries have their own documentation +outside the `gcc' directory. FIXME: document the documentation for +runtime libraries somewhere. + +* Menu: + +* Texinfo Manuals:: GCC manuals in Texinfo format. +* Man Page Generation:: Generating man pages from Texinfo manuals. +* Miscellaneous Docs:: Miscellaneous text files with documentation. + + +File: gccint.info, Node: Texinfo Manuals, Next: Man Page Generation, Up: Documentation + +6.3.7.1 Texinfo Manuals +....................... + +The manuals for GCC as a whole, and the C and C++ front ends, are in +files `doc/*.texi'. Other front ends have their own manuals in files +`LANGUAGE/*.texi'. Common files `doc/include/*.texi' are provided +which may be included in multiple manuals; the following files are in +`doc/include': + +`fdl.texi' + The GNU Free Documentation License. + +`funding.texi' + The section "Funding Free Software". + +`gcc-common.texi' + Common definitions for manuals. + +`gpl.texi' +`gpl_v3.texi' + The GNU General Public License. + +`texinfo.tex' + A copy of `texinfo.tex' known to work with the GCC manuals. + + DVI-formatted manuals are generated by `make dvi', which uses +`texi2dvi' (via the Makefile macro `$(TEXI2DVI)'). PDF-formatted +manuals are generated by `make pdf', which uses `texi2pdf' (via the +Makefile macro `$(TEXI2PDF)'). HTML formatted manuals are generated by +`make html'. Info manuals are generated by `make info' (which is run +as part of a bootstrap); this generates the manuals in the source +directory, using `makeinfo' via the Makefile macro `$(MAKEINFO)', and +they are included in release distributions. + + Manuals are also provided on the GCC web site, in both HTML and +PostScript forms. This is done via the script +`maintainer-scripts/update_web_docs_svn'. Each manual to be provided +online must be listed in the definition of `MANUALS' in that file; a +file `NAME.texi' must only appear once in the source tree, and the +output manual must have the same name as the source file. (However, +other Texinfo files, included in manuals but not themselves the root +files of manuals, may have names that appear more than once in the +source tree.) The manual file `NAME.texi' should only include other +files in its own directory or in `doc/include'. HTML manuals will be +generated by `makeinfo --html', PostScript manuals by `texi2dvi' and +`dvips', and PDF manuals by `texi2pdf'. All Texinfo files that are +parts of manuals must be version-controlled, even if they are generated +files, for the generation of online manuals to work. + + The installation manual, `doc/install.texi', is also provided on the +GCC web site. The HTML version is generated by the script +`doc/install.texi2html'. + + +File: gccint.info, Node: Man Page Generation, Next: Miscellaneous Docs, Prev: Texinfo Manuals, Up: Documentation + +6.3.7.2 Man Page Generation +........................... + +Because of user demand, in addition to full Texinfo manuals, man pages +are provided which contain extracts from those manuals. These man +pages are generated from the Texinfo manuals using +`contrib/texi2pod.pl' and `pod2man'. (The man page for `g++', +`cp/g++.1', just contains a `.so' reference to `gcc.1', but all the +other man pages are generated from Texinfo manuals.) + + Because many systems may not have the necessary tools installed to +generate the man pages, they are only generated if the `configure' +script detects that recent enough tools are installed, and the +Makefiles allow generating man pages to fail without aborting the +build. Man pages are also included in release distributions. They are +generated in the source directory. + + Magic comments in Texinfo files starting `@c man' control what parts +of a Texinfo file go into a man page. Only a subset of Texinfo is +supported by `texi2pod.pl', and it may be necessary to add support for +more Texinfo features to this script when generating new man pages. To +improve the man page output, some special Texinfo macros are provided +in `doc/include/gcc-common.texi' which `texi2pod.pl' understands: + +`@gcctabopt' + Use in the form `@table @gcctabopt' for tables of options, where + for printed output the effect of `@code' is better than that of + `@option' but for man page output a different effect is wanted. + +`@gccoptlist' + Use for summary lists of options in manuals. + +`@gol' + Use at the end of each line inside `@gccoptlist'. This is + necessary to avoid problems with differences in how the + `@gccoptlist' macro is handled by different Texinfo formatters. + + FIXME: describe the `texi2pod.pl' input language and magic comments in +more detail. + + +File: gccint.info, Node: Miscellaneous Docs, Prev: Man Page Generation, Up: Documentation + +6.3.7.3 Miscellaneous Documentation +................................... + +In addition to the formal documentation that is installed by GCC, there +are several other text files in the `gcc' subdirectory with +miscellaneous documentation: + +`ABOUT-GCC-NLS' + Notes on GCC's Native Language Support. FIXME: this should be + part of this manual rather than a separate file. + +`ABOUT-NLS' + Notes on the Free Translation Project. + +`COPYING' +`COPYING3' + The GNU General Public License, Versions 2 and 3. + +`COPYING.LIB' +`COPYING3.LIB' + The GNU Lesser General Public License, Versions 2.1 and 3. + +`*ChangeLog*' +`*/ChangeLog*' + Change log files for various parts of GCC. + +`LANGUAGES' + Details of a few changes to the GCC front-end interface. FIXME: + the information in this file should be part of general + documentation of the front-end interface in this manual. + +`ONEWS' + Information about new features in old versions of GCC. (For recent + versions, the information is on the GCC web site.) + +`README.Portability' + Information about portability issues when writing code in GCC. + FIXME: why isn't this part of this manual or of the GCC Coding + Conventions? + + FIXME: document such files in subdirectories, at least `config', `cp', +`objc', `testsuite'. + + +File: gccint.info, Node: Front End, Next: Back End, Prev: Documentation, Up: gcc Directory + +6.3.8 Anatomy of a Language Front End +------------------------------------- + +A front end for a language in GCC has the following parts: + + * A directory `LANGUAGE' under `gcc' containing source files for + that front end. *Note The Front End `LANGUAGE' Directory: Front + End Directory, for details. + + * A mention of the language in the list of supported languages in + `gcc/doc/install.texi'. + + * A mention of the name under which the language's runtime library is + recognized by `--enable-shared=PACKAGE' in the documentation of + that option in `gcc/doc/install.texi'. + + * A mention of any special prerequisites for building the front end + in the documentation of prerequisites in `gcc/doc/install.texi'. + + * Details of contributors to that front end in + `gcc/doc/contrib.texi'. If the details are in that front end's + own manual then there should be a link to that manual's list in + `contrib.texi'. + + * Information about support for that language in + `gcc/doc/frontends.texi'. + + * Information about standards for that language, and the front end's + support for them, in `gcc/doc/standards.texi'. This may be a link + to such information in the front end's own manual. + + * Details of source file suffixes for that language and `-x LANG' + options supported, in `gcc/doc/invoke.texi'. + + * Entries in `default_compilers' in `gcc.c' for source file suffixes + for that language. + + * Preferably testsuites, which may be under `gcc/testsuite' or + runtime library directories. FIXME: document somewhere how to + write testsuite harnesses. + + * Probably a runtime library for the language, outside the `gcc' + directory. FIXME: document this further. + + * Details of the directories of any runtime libraries in + `gcc/doc/sourcebuild.texi'. + + * Check targets in `Makefile.def' for the top-level `Makefile' to + check just the compiler or the compiler and runtime library for the + language. + + If the front end is added to the official GCC source repository, the +following are also necessary: + + * At least one Bugzilla component for bugs in that front end and + runtime libraries. This category needs to be added to the + Bugzilla database. + + * Normally, one or more maintainers of that front end listed in + `MAINTAINERS'. + + * Mentions on the GCC web site in `index.html' and `frontends.html', + with any relevant links on `readings.html'. (Front ends that are + not an official part of GCC may also be listed on + `frontends.html', with relevant links.) + + * A news item on `index.html', and possibly an announcement on the + <gcc-announce@gcc.gnu.org> mailing list. + + * The front end's manuals should be mentioned in + `maintainer-scripts/update_web_docs_svn' (*note Texinfo Manuals::) + and the online manuals should be linked to from + `onlinedocs/index.html'. + + * Any old releases or CVS repositories of the front end, before its + inclusion in GCC, should be made available on the GCC FTP site + `ftp://gcc.gnu.org/pub/gcc/old-releases/'. + + * The release and snapshot script `maintainer-scripts/gcc_release' + should be updated to generate appropriate tarballs for this front + end. + + * If this front end includes its own version files that include the + current date, `maintainer-scripts/update_version' should be + updated accordingly. + +* Menu: + +* Front End Directory:: The front end `LANGUAGE' directory. +* Front End Config:: The front end `config-lang.in' file. +* Front End Makefile:: The front end `Make-lang.in' file. + + +File: gccint.info, Node: Front End Directory, Next: Front End Config, Up: Front End + +6.3.8.1 The Front End `LANGUAGE' Directory +.......................................... + +A front end `LANGUAGE' directory contains the source files of that +front end (but not of any runtime libraries, which should be outside +the `gcc' directory). This includes documentation, and possibly some +subsidiary programs built alongside the front end. Certain files are +special and other parts of the compiler depend on their names: + +`config-lang.in' + This file is required in all language subdirectories. *Note The + Front End `config-lang.in' File: Front End Config, for details of + its contents + +`Make-lang.in' + This file is required in all language subdirectories. *Note The + Front End `Make-lang.in' File: Front End Makefile, for details of + its contents. + +`lang.opt' + This file registers the set of switches that the front end accepts + on the command line, and their `--help' text. *Note Options::. + +`lang-specs.h' + This file provides entries for `default_compilers' in `gcc.c' + which override the default of giving an error that a compiler for + that language is not installed. + +`LANGUAGE-tree.def' + This file, which need not exist, defines any language-specific tree + codes. + + +File: gccint.info, Node: Front End Config, Next: Front End Makefile, Prev: Front End Directory, Up: Front End + +6.3.8.2 The Front End `config-lang.in' File +........................................... + +Each language subdirectory contains a `config-lang.in' file. In +addition the main directory contains `c-config-lang.in', which contains +limited information for the C language. This file is a shell script +that may define some variables describing the language: + +`language' + This definition must be present, and gives the name of the language + for some purposes such as arguments to `--enable-languages'. + +`lang_requires' + If defined, this variable lists (space-separated) language front + ends other than C that this front end requires to be enabled (with + the names given being their `language' settings). For example, the + Java front end depends on the C++ front end, so sets + `lang_requires=c++'. + +`subdir_requires' + If defined, this variable lists (space-separated) front end + directories other than C that this front end requires to be + present. For example, the Objective-C++ front end uses source + files from the C++ and Objective-C front ends, so sets + `subdir_requires="cp objc"'. + +`target_libs' + If defined, this variable lists (space-separated) targets in the + top level `Makefile' to build the runtime libraries for this + language, such as `target-libobjc'. + +`lang_dirs' + If defined, this variable lists (space-separated) top level + directories (parallel to `gcc'), apart from the runtime libraries, + that should not be configured if this front end is not built. + +`build_by_default' + If defined to `no', this language front end is not built unless + enabled in a `--enable-languages' argument. Otherwise, front ends + are built by default, subject to any special logic in + `configure.ac' (as is present to disable the Ada front end if the + Ada compiler is not already installed). + +`boot_language' + If defined to `yes', this front end is built in stage1 of the + bootstrap. This is only relevant to front ends written in their + own languages. + +`compilers' + If defined, a space-separated list of compiler executables that + will be run by the driver. The names here will each end with + `\$(exeext)'. + +`outputs' + If defined, a space-separated list of files that should be + generated by `configure' substituting values in them. This + mechanism can be used to create a file `LANGUAGE/Makefile' from + `LANGUAGE/Makefile.in', but this is deprecated, building + everything from the single `gcc/Makefile' is preferred. + +`gtfiles' + If defined, a space-separated list of files that should be scanned + by `gengtype.c' to generate the garbage collection tables and + routines for this language. This excludes the files that are + common to all front ends. *Note Type Information::. + + + +File: gccint.info, Node: Front End Makefile, Prev: Front End Config, Up: Front End + +6.3.8.3 The Front End `Make-lang.in' File +......................................... + +Each language subdirectory contains a `Make-lang.in' file. It contains +targets `LANG.HOOK' (where `LANG' is the setting of `language' in +`config-lang.in') for the following values of `HOOK', and any other +Makefile rules required to build those targets (which may if necessary +use other Makefiles specified in `outputs' in `config-lang.in', +although this is deprecated). It also adds any testsuite targets that +can use the standard rule in `gcc/Makefile.in' to the variable +`lang_checks'. + +`all.cross' +`start.encap' +`rest.encap' + FIXME: exactly what goes in each of these targets? + +`tags' + Build an `etags' `TAGS' file in the language subdirectory in the + source tree. + +`info' + Build info documentation for the front end, in the build directory. + This target is only called by `make bootstrap' if a suitable + version of `makeinfo' is available, so does not need to check for + this, and should fail if an error occurs. + +`dvi' + Build DVI documentation for the front end, in the build directory. + This should be done using `$(TEXI2DVI)', with appropriate `-I' + arguments pointing to directories of included files. + +`pdf' + Build PDF documentation for the front end, in the build directory. + This should be done using `$(TEXI2PDF)', with appropriate `-I' + arguments pointing to directories of included files. + +`html' + Build HTML documentation for the front end, in the build directory. + +`man' + Build generated man pages for the front end from Texinfo manuals + (*note Man Page Generation::), in the build directory. This target + is only called if the necessary tools are available, but should + ignore errors so as not to stop the build if errors occur; man + pages are optional and the tools involved may be installed in a + broken way. + +`install-common' + Install everything that is part of the front end, apart from the + compiler executables listed in `compilers' in `config-lang.in'. + +`install-info' + Install info documentation for the front end, if it is present in + the source directory. This target should have dependencies on + info files that should be installed. + +`install-man' + Install man pages for the front end. This target should ignore + errors. + +`install-plugin' + Install headers needed for plugins. + +`srcextra' + Copies its dependencies into the source directory. This generally + should be used for generated files such as Bison output files + which are not version-controlled, but should be included in any + release tarballs. This target will be executed during a bootstrap + if `--enable-generated-files-in-srcdir' was specified as a + `configure' option. + +`srcinfo' +`srcman' + Copies its dependencies into the source directory. These targets + will be executed during a bootstrap if + `--enable-generated-files-in-srcdir' was specified as a + `configure' option. + +`uninstall' + Uninstall files installed by installing the compiler. This is + currently documented not to be supported, so the hook need not do + anything. + +`mostlyclean' +`clean' +`distclean' +`maintainer-clean' + The language parts of the standard GNU `*clean' targets. *Note + Standard Targets for Users: (standards)Standard Targets, for + details of the standard targets. For GCC, `maintainer-clean' + should delete all generated files in the source directory that are + not version-controlled, but should not delete anything that is. + + `Make-lang.in' must also define a variable `LANG_OBJS' to a list of +host object files that are used by that language. + + +File: gccint.info, Node: Back End, Prev: Front End, Up: gcc Directory + +6.3.9 Anatomy of a Target Back End +---------------------------------- + +A back end for a target architecture in GCC has the following parts: + + * A directory `MACHINE' under `gcc/config', containing a machine + description `MACHINE.md' file (*note Machine Descriptions: Machine + Desc.), header files `MACHINE.h' and `MACHINE-protos.h' and a + source file `MACHINE.c' (*note Target Description Macros and + Functions: Target Macros.), possibly a target Makefile fragment + `t-MACHINE' (*note The Target Makefile Fragment: Target + Fragment.), and maybe some other files. The names of these files + may be changed from the defaults given by explicit specifications + in `config.gcc'. + + * If necessary, a file `MACHINE-modes.def' in the `MACHINE' + directory, containing additional machine modes to represent + condition codes. *Note Condition Code::, for further details. + + * An optional `MACHINE.opt' file in the `MACHINE' directory, + containing a list of target-specific options. You can also add + other option files using the `extra_options' variable in + `config.gcc'. *Note Options::. + + * Entries in `config.gcc' (*note The `config.gcc' File: System + Config.) for the systems with this target architecture. + + * Documentation in `gcc/doc/invoke.texi' for any command-line + options supported by this target (*note Run-time Target + Specification: Run-time Target.). This means both entries in the + summary table of options and details of the individual options. + + * Documentation in `gcc/doc/extend.texi' for any target-specific + attributes supported (*note Defining target-specific uses of + `__attribute__': Target Attributes.), including where the same + attribute is already supported on some targets, which are + enumerated in the manual. + + * Documentation in `gcc/doc/extend.texi' for any target-specific + pragmas supported. + + * Documentation in `gcc/doc/extend.texi' of any target-specific + built-in functions supported. + + * Documentation in `gcc/doc/extend.texi' of any target-specific + format checking styles supported. + + * Documentation in `gcc/doc/md.texi' of any target-specific + constraint letters (*note Constraints for Particular Machines: + Machine Constraints.). + + * A note in `gcc/doc/contrib.texi' under the person or people who + contributed the target support. + + * Entries in `gcc/doc/install.texi' for all target triplets + supported with this target architecture, giving details of any + special notes about installation for this target, or saying that + there are no special notes if there are none. + + * Possibly other support outside the `gcc' directory for runtime + libraries. FIXME: reference docs for this. The `libstdc++' + porting manual needs to be installed as info for this to work, or + to be a chapter of this manual. + + If the back end is added to the official GCC source repository, the +following are also necessary: + + * An entry for the target architecture in `readings.html' on the GCC + web site, with any relevant links. + + * Details of the properties of the back end and target architecture + in `backends.html' on the GCC web site. + + * A news item about the contribution of support for that target + architecture, in `index.html' on the GCC web site. + + * Normally, one or more maintainers of that target listed in + `MAINTAINERS'. Some existing architectures may be unmaintained, + but it would be unusual to add support for a target that does not + have a maintainer when support is added. + + +File: gccint.info, Node: Testsuites, Next: Options, Prev: Source Tree, Up: Top + +7 Testsuites +************ + +GCC contains several testsuites to help maintain compiler quality. +Most of the runtime libraries and language front ends in GCC have +testsuites. Currently only the C language testsuites are documented +here; FIXME: document the others. + +* Menu: + +* Test Idioms:: Idioms used in testsuite code. +* Test Directives:: Directives used within DejaGnu tests. +* Ada Tests:: The Ada language testsuites. +* C Tests:: The C language testsuites. +* libgcj Tests:: The Java library testsuites. +* LTO Testing:: Support for testing link-time optimizations. +* gcov Testing:: Support for testing gcov. +* profopt Testing:: Support for testing profile-directed optimizations. +* compat Testing:: Support for testing binary compatibility. +* Torture Tests:: Support for torture testing using multiple options. + + +File: gccint.info, Node: Test Idioms, Next: Test Directives, Up: Testsuites + +7.1 Idioms Used in Testsuite Code +================================= + +In general, C testcases have a trailing `-N.c', starting with `-1.c', +in case other testcases with similar names are added later. If the +test is a test of some well-defined feature, it should have a name +referring to that feature such as `FEATURE-1.c'. If it does not test a +well-defined feature but just happens to exercise a bug somewhere in +the compiler, and a bug report has been filed for this bug in the GCC +bug database, `prBUG-NUMBER-1.c' is the appropriate form of name. +Otherwise (for miscellaneous bugs not filed in the GCC bug database), +and previously more generally, test cases are named after the date on +which they were added. This allows people to tell at a glance whether +a test failure is because of a recently found bug that has not yet been +fixed, or whether it may be a regression, but does not give any other +information about the bug or where discussion of it may be found. Some +other language testsuites follow similar conventions. + + In the `gcc.dg' testsuite, it is often necessary to test that an error +is indeed a hard error and not just a warning--for example, where it is +a constraint violation in the C standard, which must become an error +with `-pedantic-errors'. The following idiom, where the first line +shown is line LINE of the file and the line that generates the error, +is used for this: + + /* { dg-bogus "warning" "warning in place of error" } */ + /* { dg-error "REGEXP" "MESSAGE" { target *-*-* } LINE } */ + + It may be necessary to check that an expression is an integer constant +expression and has a certain value. To check that `E' has value `V', +an idiom similar to the following is used: + + char x[((E) == (V) ? 1 : -1)]; + + In `gcc.dg' tests, `__typeof__' is sometimes used to make assertions +about the types of expressions. See, for example, +`gcc.dg/c99-condexpr-1.c'. The more subtle uses depend on the exact +rules for the types of conditional expressions in the C standard; see, +for example, `gcc.dg/c99-intconst-1.c'. + + It is useful to be able to test that optimizations are being made +properly. This cannot be done in all cases, but it can be done where +the optimization will lead to code being optimized away (for example, +where flow analysis or alias analysis should show that certain code +cannot be called) or to functions not being called because they have +been expanded as built-in functions. Such tests go in +`gcc.c-torture/execute'. Where code should be optimized away, a call +to a nonexistent function such as `link_failure ()' may be inserted; a +definition + + #ifndef __OPTIMIZE__ + void + link_failure (void) + { + abort (); + } + #endif + +will also be needed so that linking still succeeds when the test is run +without optimization. When all calls to a built-in function should +have been optimized and no calls to the non-built-in version of the +function should remain, that function may be defined as `static' to +call `abort ()' (although redeclaring a function as static may not work +on all targets). + + All testcases must be portable. Target-specific testcases must have +appropriate code to avoid causing failures on unsupported systems; +unfortunately, the mechanisms for this differ by directory. + + FIXME: discuss non-C testsuites here. + + +File: gccint.info, Node: Test Directives, Next: Ada Tests, Prev: Test Idioms, Up: Testsuites + +7.2 Directives used within DejaGnu tests +======================================== + +* Menu: + +* Directives:: Syntax and descriptions of test directives. +* Selectors:: Selecting targets to which a test applies. +* Effective-Target Keywords:: Keywords describing target attributes. +* Add Options:: Features for `dg-add-options' +* Require Support:: Variants of `dg-require-SUPPORT' +* Final Actions:: Commands for use in `dg-final' + + +File: gccint.info, Node: Directives, Next: Selectors, Up: Test Directives + +7.2.1 Syntax and Descriptions of test directives +------------------------------------------------ + +Test directives appear within comments in a test source file and begin +with `dg-'. Some of these are defined within DejaGnu and others are +local to the GCC testsuite. + + The order in which test directives appear in a test can be important: +directives local to GCC sometimes override information used by the +DejaGnu directives, which know nothing about the GCC directives, so the +DejaGnu directives must precede GCC directives. + + Several test directives include selectors (*note Selectors::) which +are usually preceded by the keyword `target' or `xfail'. + +7.2.1.1 Specify how to build the test +..................................... + +`{ dg-do DO-WHAT-KEYWORD [{ target/xfail SELECTOR }] }' + DO-WHAT-KEYWORD specifies how the test is compiled and whether it + is executed. It is one of: + + `preprocess' + Compile with `-E' to run only the preprocessor. + + `compile' + Compile with `-S' to produce an assembly code file. + + `assemble' + Compile with `-c' to produce a relocatable object file. + + `link' + Compile, assemble, and link to produce an executable file. + + `run' + Produce and run an executable file, which is expected to + return an exit code of 0. + + The default is `compile'. That can be overridden for a set of + tests by redefining `dg-do-what-default' within the `.exp' file + for those tests. + + If the directive includes the optional `{ target SELECTOR }' then + the test is skipped unless the target system matches the SELECTOR. + + If DO-WHAT-KEYWORD is `run' and the directive includes the + optional `{ xfail SELECTOR }' and the selector is met then the + test is expected to fail. The `xfail' clause is ignored for other + values of DO-WHAT-KEYWORD; those tests can use directive + `dg-xfail-if'. + +7.2.1.2 Specify additional compiler options +........................................... + +`{ dg-options OPTIONS [{ target SELECTOR }] }' + This DejaGnu directive provides a list of compiler options, to be + used if the target system matches SELECTOR, that replace the + default options used for this set of tests. + +`{ dg-add-options FEATURE ... }' + Add any compiler options that are needed to access certain + features. This directive does nothing on targets that enable the + features by default, or that don't provide them at all. It must + come after all `dg-options' directives. For supported values of + FEATURE see *note Add Options::. + +7.2.1.3 Modify the test timeout value +..................................... + +The normal timeout limit, in seconds, is found by searching the +following in order: + + * the value defined by an earlier `dg-timeout' directive in the test + + * variable TOOL_TIMEOUT defined by the set of tests + + * GCC,TIMEOUT set in the target board + + * 300 + +`{ dg-timeout N [{target SELECTOR }] }' + Set the time limit for the compilation and for the execution of + the test to the specified number of seconds. + +`{ dg-timeout-factor X [{ target SELECTOR }] }' + Multiply the normal time limit for compilation and execution of + the test by the specified floating-point factor. + +7.2.1.4 Skip a test for some targets +.................................... + +`{ dg-skip-if COMMENT { SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]] }' + Arguments INCLUDE-OPTS and EXCLUDE-OPTS are lists in which each + element is a string of zero or more GCC options. Skip the test if + all of the following conditions are met: + * the test system is included in SELECTOR + + * for at least one of the option strings in INCLUDE-OPTS, every + option from that string is in the set of options with which + the test would be compiled; use `"*"' for an INCLUDE-OPTS list + that matches any options; that is the default if INCLUDE-OPTS + is not specified + + * for each of the option strings in EXCLUDE-OPTS, at least one + option from that string is not in the set of options with + which the test would be compiled; use `""' for an empty + EXCLUDE-OPTS list; that is the default if EXCLUDE-OPTS is not + specified + + For example, to skip a test if option `-Os' is present: + + /* { dg-skip-if "" { *-*-* } { "-Os" } { "" } } */ + + To skip a test if both options `-O2' and `-g' are present: + + /* { dg-skip-if "" { *-*-* } { "-O2 -g" } { "" } } */ + + To skip a test if either `-O2' or `-O3' is present: + + /* { dg-skip-if "" { *-*-* } { "-O2" "-O3" } { "" } } */ + + To skip a test unless option `-Os' is present: + + /* { dg-skip-if "" { *-*-* } { "*" } { "-Os" } } */ + + To skip a test if either `-O2' or `-O3' is used with `-g' but not + if `-fpic' is also present: + + /* { dg-skip-if "" { *-*-* } { "-O2 -g" "-O3 -g" } { "-fpic" } } */ + +`{ dg-require-effective-target KEYWORD [{ SELECTOR }] }' + Skip the test if the test target, including current multilib flags, + is not covered by the effective-target keyword. If the directive + includes the optional `{ SELECTOR }' then the effective-target + test is only performed if the target system matches the SELECTOR. + This directive must appear after any `dg-do' directive in the test + and before any `dg-additional-sources' directive. *Note + Effective-Target Keywords::. + +`{ dg-require-SUPPORT args }' + Skip the test if the target does not provide the required support. + These directives must appear after any `dg-do' directive in the + test and before any `dg-additional-sources' directive. They + require at least one argument, which can be an empty string if the + specific procedure does not examine the argument. *Note Require + Support::, for a complete list of these directives. + +7.2.1.5 Expect a test to fail for some targets +.............................................. + +`{ dg-xfail-if COMMENT { SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]] }' + Expect the test to fail if the conditions (which are the same as + for `dg-skip-if') are met. This does not affect the execute step. + +`{ dg-xfail-run-if COMMENT { SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]] }' + Expect the execute step of a test to fail if the conditions (which + are the same as for `dg-skip-if') are met. + +7.2.1.6 Expect the test executable to fail +.......................................... + +`{ dg-shouldfail COMMENT [{ SELECTOR } [{ INCLUDE-OPTS } [{ EXCLUDE-OPTS }]]] }' + Expect the test executable to return a nonzero exit status if the + conditions (which are the same as for `dg-skip-if') are met. + +7.2.1.7 Verify compiler messages +................................ + +`{ dg-error REGEXP [COMMENT [{ target/xfail SELECTOR } [LINE] }]] }' + This DejaGnu directive appears on a source line that is expected + to get an error message, or else specifies the source line + associated with the message. If there is no message for that line + or if the text of that message is not matched by REGEXP then the + check fails and COMMENT is included in the `FAIL' message. The + check does not look for the string `error' unless it is part of + REGEXP. + +`{ dg-warning REGEXP [COMMENT [{ target/xfail SELECTOR } [LINE] }]] }' + This DejaGnu directive appears on a source line that is expected + to get a warning message, or else specifies the source line + associated with the message. If there is no message for that line + or if the text of that message is not matched by REGEXP then the + check fails and COMMENT is included in the `FAIL' message. The + check does not look for the string `warning' unless it is part of + REGEXP. + +`{ dg-message REGEXP [COMMENT [{ target/xfail SELECTOR } [LINE] }]] }' + The line is expected to get a message other than an error or + warning. If there is no message for that line or if the text of + that message is not matched by REGEXP then the check fails and + COMMENT is included in the `FAIL' message. + +`{ dg-bogus REGEXP [COMMENT [{ target/xfail SELECTOR } [LINE] }]] }' + This DejaGnu directive appears on a source line that should not + get a message matching REGEXP, or else specifies the source line + associated with the bogus message. It is usually used with `xfail' + to indicate that the message is a known problem for a particular + set of targets. + +`{ dg-excess-errors COMMENT [{ target/xfail SELECTOR }] }' + This DejaGnu directive indicates that the test is expected to fail + due to compiler messages that are not handled by `dg-error', + `dg-warning' or `dg-bogus'. For this directive `xfail' has the + same effect as `target'. + +`{ dg-prune-output REGEXP }' + Prune messages matching REGEXP from the test output. + +7.2.1.8 Verify output of the test executable +............................................ + +`{ dg-output REGEXP [{ target/xfail SELECTOR }] }' + This DejaGnu directive compares REGEXP to the combined output that + the test executable writes to `stdout' and `stderr'. + +7.2.1.9 Specify additional files for a test +........................................... + +`{ dg-additional-files "FILELIST" }' + Specify additional files, other than source files, that must be + copied to the system where the compiler runs. + +`{ dg-additional-sources "FILELIST" }' + Specify additional source files to appear in the compile line + following the main test file. + +7.2.1.10 Add checks at the end of a test +........................................ + +`{ dg-final { LOCAL-DIRECTIVE } }' + This DejaGnu directive is placed within a comment anywhere in the + source file and is processed after the test has been compiled and + run. Multiple `dg-final' commands are processed in the order in + which they appear in the source file. *Note Final Actions::, for + a list of directives that can be used within `dg-final'. + + +File: gccint.info, Node: Selectors, Next: Effective-Target Keywords, Prev: Directives, Up: Test Directives + +7.2.2 Selecting targets to which a test applies +----------------------------------------------- + +Several test directives include SELECTORs to limit the targets for +which a test is run or to declare that a test is expected to fail on +particular targets. + + A selector is: + * one or more target triplets, possibly including wildcard characters + + * a single effective-target keyword (*note Effective-Target + Keywords::) + + * a logical expression + + Depending on the context, the selector specifies whether a test is +skipped and reported as unsupported or is expected to fail. Use +`*-*-*' to match any target. + + A selector expression appears within curly braces and uses a single +logical operator: one of `!', `&&', or `||'. An operand is another +selector expression, an effective-target keyword, a single target +triplet, or a list of target triplets within quotes or curly braces. +For example: + + { target { ! "hppa*-*-* ia64*-*-*" } } + { target { powerpc*-*-* && lp64 } } + { xfail { lp64 || vect_no_align } } + + +File: gccint.info, Node: Effective-Target Keywords, Next: Add Options, Prev: Selectors, Up: Test Directives + +7.2.3 Keywords describing target attributes +------------------------------------------- + +Effective-target keywords identify sets of targets that support +particular functionality. They are used to limit tests to be run only +for particular targets, or to specify that particular sets of targets +are expected to fail some tests. + + Effective-target keywords are defined in `lib/target-supports.exp' in +the GCC testsuite, with the exception of those that are documented as +being local to a particular test directory. + + The `effective target' takes into account all of the compiler options +with which the test will be compiled, including the multilib options. +By convention, keywords ending in `_nocache' can also include options +specified for the particular test in an earlier `dg-options' or +`dg-add-options' directive. + +7.2.3.1 Data type sizes +....................... + +`ilp32' + Target has 32-bit `int', `long', and pointers. + +`lp64' + Target has 32-bit `int', 64-bit `long' and pointers. + +`llp64' + Target has 32-bit `int' and `long', 64-bit `long long' and + pointers. + +`double64' + Target has 64-bit `double'. + +`double64plus' + Target has `double' that is 64 bits or longer. + +`int32plus' + Target has `int' that is at 32 bits or longer. + +`int16' + Target has `int' that is 16 bits or shorter. + +`large_double' + Target supports `double' that is longer than `float'. + +`large_long_double' + Target supports `long double' that is longer than `double'. + +`ptr32plus' + Target has pointers that are 32 bits or longer. + +`size32plus' + Target supports array and structure sizes that are 32 bits or + longer. + +`4byte_wchar_t' + Target has `wchar_t' that is at least 4 bytes. + +7.2.3.2 Fortran-specific attributes +................................... + +`fortran_integer_16' + Target supports Fortran `integer' that is 16 bytes or longer. + +`fortran_large_int' + Target supports Fortran `integer' kinds larger than `integer(8)'. + +`fortran_large_real' + Target supports Fortran `real' kinds larger than `real(8)'. + +7.2.3.3 Vector-specific attributes +.................................. + +`vect_condition' + Target supports vector conditional operations. + +`vect_double' + Target supports hardware vectors of `double'. + +`vect_float' + Target supports hardware vectors of `float'. + +`vect_int' + Target supports hardware vectors of `int'. + +`vect_long' + Target supports hardware vectors of `long'. + +`vect_long_long' + Target supports hardware vectors of `long long'. + +`vect_aligned_arrays' + Target aligns arrays to vector alignment boundary. + +`vect_hw_misalign' + Target supports a vector misalign access. + +`vect_no_align' + Target does not support a vector alignment mechanism. + +`vect_no_int_max' + Target does not support a vector max instruction on `int'. + +`vect_no_int_add' + Target does not support a vector add instruction on `int'. + +`vect_no_bitwise' + Target does not support vector bitwise instructions. + +`vect_char_mult' + Target supports `vector char' multiplication. + +`vect_short_mult' + Target supports `vector short' multiplication. + +`vect_int_mult' + Target supports `vector int' multiplication. + +`vect_extract_even_odd' + Target supports vector even/odd element extraction. + +`vect_extract_even_odd_wide' + Target supports vector even/odd element extraction of vectors with + elements `SImode' or larger. + +`vect_interleave' + Target supports vector interleaving. + +`vect_strided' + Target supports vector interleaving and extract even/odd. + +`vect_strided_wide' + Target supports vector interleaving and extract even/odd for wide + element types. + +`vect_perm' + Target supports vector permutation. + +`vect_shift' + Target supports a hardware vector shift operation. + +`vect_widen_sum_hi_to_si' + Target supports a vector widening summation of `short' operands + into `int' results, or can promote (unpack) from `short' to `int'. + +`vect_widen_sum_qi_to_hi' + Target supports a vector widening summation of `char' operands + into `short' results, or can promote (unpack) from `char' to + `short'. + +`vect_widen_sum_qi_to_si' + Target supports a vector widening summation of `char' operands + into `int' results. + +`vect_widen_mult_qi_to_hi' + Target supports a vector widening multiplication of `char' operands + into `short' results, or can promote (unpack) from `char' to + `short' and perform non-widening multiplication of `short'. + +`vect_widen_mult_hi_to_si' + Target supports a vector widening multiplication of `short' + operands into `int' results, or can promote (unpack) from `short' + to `int' and perform non-widening multiplication of `int'. + +`vect_sdot_qi' + Target supports a vector dot-product of `signed char'. + +`vect_udot_qi' + Target supports a vector dot-product of `unsigned char'. + +`vect_sdot_hi' + Target supports a vector dot-product of `signed short'. + +`vect_udot_hi' + Target supports a vector dot-product of `unsigned short'. + +`vect_pack_trunc' + Target supports a vector demotion (packing) of `short' to `char' + and from `int' to `short' using modulo arithmetic. + +`vect_unpack' + Target supports a vector promotion (unpacking) of `char' to `short' + and from `char' to `int'. + +`vect_intfloat_cvt' + Target supports conversion from `signed int' to `float'. + +`vect_uintfloat_cvt' + Target supports conversion from `unsigned int' to `float'. + +`vect_floatint_cvt' + Target supports conversion from `float' to `signed int'. + +`vect_floatuint_cvt' + Target supports conversion from `float' to `unsigned int'. + +7.2.3.4 Thread Local Storage attributes +....................................... + +`tls' + Target supports thread-local storage. + +`tls_native' + Target supports native (rather than emulated) thread-local storage. + +`tls_runtime' + Test system supports executing TLS executables. + +7.2.3.5 Decimal floating point attributes +......................................... + +`dfp' + Targets supports compiling decimal floating point extension to C. + +`dfp_nocache' + Including the options used to compile this particular test, the + target supports compiling decimal floating point extension to C. + +`dfprt' + Test system can execute decimal floating point tests. + +`dfprt_nocache' + Including the options used to compile this particular test, the + test system can execute decimal floating point tests. + +`hard_dfp' + Target generates decimal floating point instructions with current + options. + +7.2.3.6 ARM-specific attributes +............................... + +`arm32' + ARM target generates 32-bit code. + +`arm_eabi' + ARM target adheres to the ABI for the ARM Architecture. + +`arm_hard_vfp_ok' + ARM target supports `-mfpu=vfp -mfloat-abi=hard'. Some multilibs + may be incompatible with these options. + +`arm_iwmmxt_ok' + ARM target supports `-mcpu=iwmmxt'. Some multilibs may be + incompatible with this option. + +`arm_neon' + ARM target supports generating NEON instructions. + +`arm_neon_hw' + Test system supports executing NEON instructions. + +`arm_neon_ok' + ARM Target supports `-mfpu=neon -mfloat-abi=softfp' or compatible + options. Some multilibs may be incompatible with these options. + +`arm_neon_fp16_ok' + ARM Target supports `-mfpu=neon-fp16 -mfloat-abi=softfp' or + compatible options. Some multilibs may be incompatible with these + options. + +`arm_thumb1_ok' + ARM target generates Thumb-1 code for `-mthumb'. + +`arm_thumb2_ok' + ARM target generates Thumb-2 code for `-mthumb'. + +`arm_vfp_ok' + ARM target supports `-mfpu=vfp -mfloat-abi=softfp'. Some + multilibs may be incompatible with these options. + +7.2.3.7 MIPS-specific attributes +................................ + +`mips64' + MIPS target supports 64-bit instructions. + +`nomips16' + MIPS target does not produce MIPS16 code. + +`mips16_attribute' + MIPS target can generate MIPS16 code. + +`mips_loongson' + MIPS target is a Loongson-2E or -2F target using an ABI that + supports the Loongson vector modes. + +`mips_newabi_large_long_double' + MIPS target supports `long double' larger than `double' when using + the new ABI. + +`mpaired_single' + MIPS target supports `-mpaired-single'. + +7.2.3.8 PowerPC-specific attributes +................................... + +`powerpc64' + Test system supports executing 64-bit instructions. + +`powerpc_altivec' + PowerPC target supports AltiVec. + +`powerpc_altivec_ok' + PowerPC target supports `-maltivec'. + +`powerpc_fprs' + PowerPC target supports floating-point registers. + +`powerpc_hard_double' + PowerPC target supports hardware double-precision floating-point. + +`powerpc_ppu_ok' + PowerPC target supports `-mcpu=cell'. + +`powerpc_spe' + PowerPC target supports PowerPC SPE. + +`powerpc_spe_nocache' + Including the options used to compile this particular test, the + PowerPC target supports PowerPC SPE. + +`powerpc_spu' + PowerPC target supports PowerPC SPU. + +`spu_auto_overlay' + SPU target has toolchain that supports automatic overlay + generation. + +`powerpc_vsx_ok' + PowerPC target supports `-mvsx'. + +`powerpc_405_nocache' + Including the options used to compile this particular test, the + PowerPC target supports PowerPC 405. + +`vmx_hw' + PowerPC target supports executing AltiVec instructions. + +7.2.3.9 Other hardware attributes +................................. + +`avx' + Target supports compiling `avx' instructions. + +`avx_runtime' + Target supports the execution of `avx' instructions. + +`cell_hw' + Test system can execute AltiVec and Cell PPU instructions. + +`coldfire_fpu' + Target uses a ColdFire FPU. + +`hard_float' + Target supports FPU instructions. + +`sse' + Target supports compiling `sse' instructions. + +`sse_runtime' + Target supports the execution of `sse' instructions. + +`sse2' + Target supports compiling `sse2' instructions. + +`sse2_runtime' + Target supports the execution of `sse2' instructions. + +`sync_char_short' + Target supports atomic operations on `char' and `short'. + +`sync_int_long' + Target supports atomic operations on `int' and `long'. + +`ultrasparc_hw' + Test environment appears to run executables on a simulator that + accepts only `EM_SPARC' executables and chokes on `EM_SPARC32PLUS' + or `EM_SPARCV9' executables. + +`vect_cmdline_needed' + Target requires a command line argument to enable a SIMD + instruction set. + +7.2.3.10 Environment attributes +............................... + +`c' + The language for the compiler under test is C. + +`c++' + The language for the compiler under test is C++. + +`c99_runtime' + Target provides a full C99 runtime. + +`correct_iso_cpp_string_wchar_protos' + Target `string.h' and `wchar.h' headers provide C++ required + overloads for `strchr' etc. functions. + +`dummy_wcsftime' + Target uses a dummy `wcsftime' function that always returns zero. + +`fd_truncate' + Target can truncate a file from a file descriptor, as used by + `libgfortran/io/unix.c:fd_truncate'; i.e. `ftruncate' or `chsize'. + +`freestanding' + Target is `freestanding' as defined in section 4 of the C99 + standard. Effectively, it is a target which supports no extra + headers or libraries other than what is considered essential. + +`init_priority' + Target supports constructors with initialization priority + arguments. + +`inttypes_types' + Target has the basic signed and unsigned types in `inttypes.h'. + This is for tests that GCC's notions of these types agree with + those in the header, as some systems have only `inttypes.h'. + +`lax_strtofp' + Target might have errors of a few ULP in string to floating-point + conversion functions and overflow is not always detected correctly + by those functions. + +`newlib' + Target supports Newlib. + +`pow10' + Target provides `pow10' function. + +`pthread' + Target can compile using `pthread.h' with no errors or warnings. + +`pthread_h' + Target has `pthread.h'. + +`run_expensive_tests' + Expensive testcases (usually those that consume excessive amounts + of CPU time) should be run on this target. This can be enabled by + setting the `GCC_TEST_RUN_EXPENSIVE' environment variable to a + non-empty string. + +`simulator' + Test system runs executables on a simulator (i.e. slowly) rather + than hardware (i.e. fast). + +`stdint_types' + Target has the basic signed and unsigned C types in `stdint.h'. + This will be obsolete when GCC ensures a working `stdint.h' for + all targets. + +`trampolines' + Target supports trampolines. + +`uclibc' + Target supports uClibc. + +`unwrapped' + Target does not use a status wrapper. + +`vxworks_kernel' + Target is a VxWorks kernel. + +`vxworks_rtp' + Target is a VxWorks RTP. + +`wchar' + Target supports wide characters. + +7.2.3.11 Other attributes +......................... + +`automatic_stack_alignment' + Target supports automatic stack alignment. + +`cxa_atexit' + Target uses `__cxa_atexit'. + +`default_packed' + Target has packed layout of structure members by default. + +`fgraphite' + Target supports Graphite optimizations. + +`fixed_point' + Target supports fixed-point extension to C. + +`fopenmp' + Target supports OpenMP via `-fopenmp'. + +`fpic' + Target supports `-fpic' and `-fPIC'. + +`freorder' + Target supports `-freorder-blocks-and-partition'. + +`fstack_protector' + Target supports `-fstack-protector'. + +`gas' + Target uses GNU `as'. + +`gc_sections' + Target supports `--gc-sections'. + +`keeps_null_pointer_checks' + Target keeps null pointer checks, either due to the use of + `-fno-delete-null-pointer-checks' or hardwired into the target. + +`lto' + Compiler has been configured to support link-time optimization + (LTO). + +`named_sections' + Target supports named sections. + +`natural_alignment_32' + Target uses natural alignment (aligned to type size) for types of + 32 bits or less. + +`target_natural_alignment_64' + Target uses natural alignment (aligned to type size) for types of + 64 bits or less. + +`nonpic' + Target does not generate PIC by default. + +`pcc_bitfield_type_matters' + Target defines `PCC_BITFIELD_TYPE_MATTERS'. + +`pe_aligned_commons' + Target supports `-mpe-aligned-commons'. + +`section_anchors' + Target supports section anchors. + +`short_enums' + Target defaults to short enums. + +`static' + Target supports `-static'. + +`static_libgfortran' + Target supports statically linking `libgfortran'. + +`string_merging' + Target supports merging string constants at link time. + +`ucn' + Target supports compiling and assembling UCN. + +`ucn_nocache' + Including the options used to compile this particular test, the + target supports compiling and assembling UCN. + +`unaligned_stack' + Target does not guarantee that its `STACK_BOUNDARY' is greater than + or equal to the required vector alignment. + +`vector_alignment_reachable' + Vector alignment is reachable for types of 32 bits or less. + +`vector_alignment_reachable_for_64bit' + Vector alignment is reachable for types of 64 bits or less. + +`wchar_t_char16_t_compatible' + Target supports `wchar_t' that is compatible with `char16_t'. + +`wchar_t_char32_t_compatible' + Target supports `wchar_t' that is compatible with `char32_t'. + +7.2.3.12 Local to tests in `gcc.target/i386' +............................................ + +`3dnow' + Target supports compiling `3dnow' instructions. + +`aes' + Target supports compiling `aes' instructions. + +`fma4' + Target supports compiling `fma4' instructions. + +`ms_hook_prologue' + Target supports attribute `ms_hook_prologue'. + +`pclmul' + Target supports compiling `pclmul' instructions. + +`sse3' + Target supports compiling `sse3' instructions. + +`sse4' + Target supports compiling `sse4' instructions. + +`sse4a' + Target supports compiling `sse4a' instructions. + +`ssse3' + Target supports compiling `ssse3' instructions. + +`vaes' + Target supports compiling `vaes' instructions. + +`vpclmul' + Target supports compiling `vpclmul' instructions. + +`xop' + Target supports compiling `xop' instructions. + +7.2.3.13 Local to tests in `gcc.target/spu/ea' +.............................................. + +`ealib' + Target `__ea' library functions are available. + +7.2.3.14 Local to tests in `gcc.test-framework' +............................................... + +`no' + Always returns 0. + +`yes' + Always returns 1. + + +File: gccint.info, Node: Add Options, Next: Require Support, Prev: Effective-Target Keywords, Up: Test Directives + +7.2.4 Features for `dg-add-options' +----------------------------------- + +The supported values of FEATURE for directive `dg-add-options' are: + +`arm_neon' + NEON support. Only ARM targets support this feature, and only then + in certain modes; see the *note arm_neon_ok effective target + keyword: arm_neon_ok. + +`arm_neon_fp16' + NEON and half-precision floating point support. Only ARM targets + support this feature, and only then in certain modes; see the + *note arm_neon_fp16_ok effective target keyword: arm_neon_ok. + +`bind_pic_locally' + Add the target-specific flags needed to enable functions to bind + locally when using pic/PIC passes in the testsuite. + +`c99_runtime' + Add the target-specific flags needed to access the C99 runtime. + +`ieee' + Add the target-specific flags needed to enable full IEEE + compliance mode. + +`mips16_attribute' + `mips16' function attributes. Only MIPS targets support this + feature, and only then in certain modes. + +`tls' + Add the target-specific flags needed to use thread-local storage. + + +File: gccint.info, Node: Require Support, Next: Final Actions, Prev: Add Options, Up: Test Directives + +7.2.5 Variants of `dg-require-SUPPORT' +-------------------------------------- + +A few of the `dg-require' directives take arguments. + +`dg-require-iconv CODESET' + Skip the test if the target does not support iconv. CODESET is + the codeset to convert to. + +`dg-require-profiling PROFOPT' + Skip the test if the target does not support profiling with option + PROFOPT. + +`dg-require-visibility VIS' + Skip the test if the target does not support the `visibility' + attribute. If VIS is `""', support for `visibility("hidden")' is + checked, for `visibility("VIS")' otherwise. + + The original `dg-require' directives were defined before there was +support for effective-target keywords. The directives that do not take +arguments could be replaced with effective-target keywords. + +`dg-require-alias ""' + Skip the test if the target does not support the `alias' attribute. + +`dg-require-ascii-locale ""' + Skip the test if the host does not support an ASCII locale. + +`dg-require-compat-dfp ""' + Skip this test unless both compilers in a `compat' testsuite + support decimal floating point. + +`dg-require-cxa-atexit ""' + Skip the test if the target does not support `__cxa_atexit'. This + is equivalent to `dg-require-effective-target cxa_atexit'. + +`dg-require-dll ""' + Skip the test if the target does not support DLL attributes. + +`dg-require-fork ""' + Skip the test if the target does not support `fork'. + +`dg-require-gc-sections ""' + Skip the test if the target's linker does not support the + `--gc-sections' flags. This is equivalent to + `dg-require-effective-target gc-sections'. + +`dg-require-host-local ""' + Skip the test if the host is remote, rather than the same as the + build system. Some tests are incompatible with DejaGnu's handling + of remote hosts, which involves copying the source file to the + host and compiling it with a relative path and "`-o a.out'". + +`dg-require-mkfifo ""' + Skip the test if the target does not support `mkfifo'. + +`dg-require-named-sections ""' + Skip the test is the target does not support named sections. This + is equivalent to `dg-require-effective-target named_sections'. + +`dg-require-weak ""' + Skip the test if the target does not support weak symbols. + +`dg-require-weak-override ""' + Skip the test if the target does not support overriding weak + symbols. + + +File: gccint.info, Node: Final Actions, Prev: Require Support, Up: Test Directives + +7.2.6 Commands for use in `dg-final' +------------------------------------ + +The GCC testsuite defines the following directives to be used within +`dg-final'. + +7.2.6.1 Scan a particular file +.............................. + +`scan-file FILENAME REGEXP [{ target/xfail SELECTOR }]' + Passes if REGEXP matches text in FILENAME. + +`scan-file-not FILENAME REGEXP [{ target/xfail SELECTOR }]' + Passes if REGEXP does not match text in FILENAME. + +`scan-module MODULE REGEXP [{ target/xfail SELECTOR }]' + Passes if REGEXP matches in Fortran module MODULE. + +7.2.6.2 Scan the assembly output +................................ + +`scan-assembler REGEX [{ target/xfail SELECTOR }]' + Passes if REGEX matches text in the test's assembler output. + +`scan-assembler-not REGEX [{ target/xfail SELECTOR }]' + Passes if REGEX does not match text in the test's assembler output. + +`scan-assembler-times REGEX NUM [{ target/xfail SELECTOR }]' + Passes if REGEX is matched exactly NUM times in the test's + assembler output. + +`scan-assembler-dem REGEX [{ target/xfail SELECTOR }]' + Passes if REGEX matches text in the test's demangled assembler + output. + +`scan-assembler-dem-not REGEX [{ target/xfail SELECTOR }]' + Passes if REGEX does not match text in the test's demangled + assembler output. + +`scan-hidden SYMBOL [{ target/xfail SELECTOR }]' + Passes if SYMBOL is defined as a hidden symbol in the test's + assembly output. + +`scan-not-hidden SYMBOL [{ target/xfail SELECTOR }]' + Passes if SYMBOL is not defined as a hidden symbol in the test's + assembly output. + +7.2.6.3 Scan optimization dump files +.................................... + +These commands are available for KIND of `tree', `rtl', and `ipa'. + +`scan-KIND-dump REGEX SUFFIX [{ target/xfail SELECTOR }]' + Passes if REGEX matches text in the dump file with suffix SUFFIX. + +`scan-KIND-dump-not REGEX SUFFIX [{ target/xfail SELECTOR }]' + Passes if REGEX does not match text in the dump file with suffix + SUFFIX. + +`scan-KIND-dump-times REGEX NUM SUFFIX [{ target/xfail SELECTOR }]' + Passes if REGEX is found exactly NUM times in the dump file with + suffix SUFFIX. + +`scan-KIND-dump-dem REGEX SUFFIX [{ target/xfail SELECTOR }]' + Passes if REGEX matches demangled text in the dump file with + suffix SUFFIX. + +`scan-KIND-dump-dem-not REGEX SUFFIX [{ target/xfail SELECTOR }]' + Passes if REGEX does not match demangled text in the dump file with + suffix SUFFIX. + +7.2.6.4 Verify that an output files exists or not +................................................. + +`output-exists [{ target/xfail SELECTOR }]' + Passes if compiler output file exists. + +`output-exists-not [{ target/xfail SELECTOR }]' + Passes if compiler output file does not exist. + +7.2.6.5 Check for LTO tests +........................... + +`scan-symbol REGEXP [{ target/xfail SELECTOR }]' + Passes if the pattern is present in the final executable. + +7.2.6.6 Checks for `gcov' tests +............................... + +`run-gcov SOURCEFILE' + Check line counts in `gcov' tests. + +`run-gcov [branches] [calls] { OPTS SOURCEFILE }' + Check branch and/or call counts, in addition to line counts, in + `gcov' tests. + +7.2.6.7 Clean up generated test files +..................................... + +`cleanup-coverage-files' + Removes coverage data files generated for this test. + +`cleanup-ipa-dump SUFFIX' + Removes IPA dump files generated for this test. + +`cleanup-modules' + Removes Fortran module files generated for this test. + +`cleanup-profile-file' + Removes profiling files generated for this test. + +`cleanup-repo-files' + Removes files generated for this test for `-frepo'. + +`cleanup-rtl-dump SUFFIX' + Removes RTL dump files generated for this test. + +`cleanup-saved-temps' + Removes files for the current test which were kept for + `-save-temps'. + +`cleanup-tree-dump SUFFIX' + Removes tree dump files matching SUFFIX which were generated for + this test. + + +File: gccint.info, Node: Ada Tests, Next: C Tests, Prev: Test Directives, Up: Testsuites + +7.3 Ada Language Testsuites +=========================== + +The Ada testsuite includes executable tests from the ACATS 2.5 +testsuite, publicly available at +`http://www.adaic.org/compilers/acats/2.5'. + + These tests are integrated in the GCC testsuite in the `ada/acats' +directory, and enabled automatically when running `make check', assuming +the Ada language has been enabled when configuring GCC. + + You can also run the Ada testsuite independently, using `make +check-ada', or run a subset of the tests by specifying which chapter to +run, e.g.: + + $ make check-ada CHAPTERS="c3 c9" + + The tests are organized by directory, each directory corresponding to +a chapter of the Ada Reference Manual. So for example, `c9' corresponds +to chapter 9, which deals with tasking features of the language. + + There is also an extra chapter called `gcc' containing a template for +creating new executable tests, although this is deprecated in favor of +the `gnat.dg' testsuite. + + The tests are run using two `sh' scripts: `run_acats' and +`run_all.sh'. To run the tests using a simulator or a cross target, +see the small customization section at the top of `run_all.sh'. + + These tests are run using the build tree: they can be run without doing +a `make install'. + + +File: gccint.info, Node: C Tests, Next: libgcj Tests, Prev: Ada Tests, Up: Testsuites + +7.4 C Language Testsuites +========================= + +GCC contains the following C language testsuites, in the +`gcc/testsuite' directory: + +`gcc.dg' + This contains tests of particular features of the C compiler, + using the more modern `dg' harness. Correctness tests for various + compiler features should go here if possible. + + Magic comments determine whether the file is preprocessed, + compiled, linked or run. In these tests, error and warning + message texts are compared against expected texts or regular + expressions given in comments. These tests are run with the + options `-ansi -pedantic' unless other options are given in the + test. Except as noted below they are not run with multiple + optimization options. + +`gcc.dg/compat' + This subdirectory contains tests for binary compatibility using + `lib/compat.exp', which in turn uses the language-independent + support (*note Support for testing binary compatibility: compat + Testing.). + +`gcc.dg/cpp' + This subdirectory contains tests of the preprocessor. + +`gcc.dg/debug' + This subdirectory contains tests for debug formats. Tests in this + subdirectory are run for each debug format that the compiler + supports. + +`gcc.dg/format' + This subdirectory contains tests of the `-Wformat' format + checking. Tests in this directory are run with and without + `-DWIDE'. + +`gcc.dg/noncompile' + This subdirectory contains tests of code that should not compile + and does not need any special compilation options. They are run + with multiple optimization options, since sometimes invalid code + crashes the compiler with optimization. + +`gcc.dg/special' + FIXME: describe this. + +`gcc.c-torture' + This contains particular code fragments which have historically + broken easily. These tests are run with multiple optimization + options, so tests for features which only break at some + optimization levels belong here. This also contains tests to + check that certain optimizations occur. It might be worthwhile to + separate the correctness tests cleanly from the code quality + tests, but it hasn't been done yet. + +`gcc.c-torture/compat' + FIXME: describe this. + + This directory should probably not be used for new tests. + +`gcc.c-torture/compile' + This testsuite contains test cases that should compile, but do not + need to link or run. These test cases are compiled with several + different combinations of optimization options. All warnings are + disabled for these test cases, so this directory is not suitable if + you wish to test for the presence or absence of compiler warnings. + While special options can be set, and tests disabled on specific + platforms, by the use of `.x' files, mostly these test cases + should not contain platform dependencies. FIXME: discuss how + defines such as `NO_LABEL_VALUES' and `STACK_SIZE' are used. + +`gcc.c-torture/execute' + This testsuite contains test cases that should compile, link and + run; otherwise the same comments as for `gcc.c-torture/compile' + apply. + +`gcc.c-torture/execute/ieee' + This contains tests which are specific to IEEE floating point. + +`gcc.c-torture/unsorted' + FIXME: describe this. + + This directory should probably not be used for new tests. + +`gcc.misc-tests' + This directory contains C tests that require special handling. + Some of these tests have individual expect files, and others share + special-purpose expect files: + + ``bprob*.c'' + Test `-fbranch-probabilities' using + `gcc.misc-tests/bprob.exp', which in turn uses the generic, + language-independent framework (*note Support for testing + profile-directed optimizations: profopt Testing.). + + ``gcov*.c'' + Test `gcov' output using `gcov.exp', which in turn uses the + language-independent support (*note Support for testing gcov: + gcov Testing.). + + ``i386-pf-*.c'' + Test i386-specific support for data prefetch using + `i386-prefetch.exp'. + +`gcc.test-framework' + + ``dg-*.c'' + Test the testsuite itself using + `gcc.test-framework/test-framework.exp'. + + + FIXME: merge in `testsuite/README.gcc' and discuss the format of test +cases and magic comments more. + + +File: gccint.info, Node: libgcj Tests, Next: LTO Testing, Prev: C Tests, Up: Testsuites + +7.5 The Java library testsuites. +================================ + +Runtime tests are executed via `make check' in the +`TARGET/libjava/testsuite' directory in the build tree. Additional +runtime tests can be checked into this testsuite. + + Regression testing of the core packages in libgcj is also covered by +the Mauve testsuite. The Mauve Project develops tests for the Java +Class Libraries. These tests are run as part of libgcj testing by +placing the Mauve tree within the libjava testsuite sources at +`libjava/testsuite/libjava.mauve/mauve', or by specifying the location +of that tree when invoking `make', as in `make MAUVEDIR=~/mauve check'. + + To detect regressions, a mechanism in `mauve.exp' compares the +failures for a test run against the list of expected failures in +`libjava/testsuite/libjava.mauve/xfails' from the source hierarchy. +Update this file when adding new failing tests to Mauve, or when fixing +bugs in libgcj that had caused Mauve test failures. + + We encourage developers to contribute test cases to Mauve. + + +File: gccint.info, Node: LTO Testing, Next: gcov Testing, Prev: libgcj Tests, Up: Testsuites + +7.6 Support for testing link-time optimizations +=============================================== + +Tests for link-time optimizations usually require multiple source files +that are compiled separately, perhaps with different sets of options. +There are several special-purpose test directives used for these tests. + +`{ dg-lto-do DO-WHAT-KEYWORD }' + DO-WHAT-KEYWORD specifies how the test is compiled and whether it + is executed. It is one of: + + `assemble' + Compile with `-c' to produce a relocatable object file. + + `link' + Compile, assemble, and link to produce an executable file. + + `run' + Produce and run an executable file, which is expected to + return an exit code of 0. + + The default is `assemble'. That can be overridden for a set of + tests by redefining `dg-do-what-default' within the `.exp' file + for those tests. + + Unlike `dg-do', `dg-lto-do' does not support an optional `target' + or `xfail' list. Use `dg-skip-if', `dg-xfail-if', or + `dg-xfail-run-if'. + +`{ dg-lto-options { { OPTIONS } [{ OPTIONS }] } [{ target SELECTOR }]}' + This directive provides a list of one or more sets of compiler + options to override LTO_OPTIONS. Each test will be compiled and + run with each of these sets of options. + +`{ dg-extra-ld-options OPTIONS [{ target SELECTOR }]}' + This directive adds OPTIONS to the linker options used. + +`{ dg-suppress-ld-options OPTIONS [{ target SELECTOR }]}' + This directive removes OPTIONS from the set of linker options used. + + +File: gccint.info, Node: gcov Testing, Next: profopt Testing, Prev: LTO Testing, Up: Testsuites + +7.7 Support for testing `gcov' +============================== + +Language-independent support for testing `gcov', and for checking that +branch profiling produces expected values, is provided by the expect +file `lib/gcov.exp'. `gcov' tests also rely on procedures in +`lib/gcc-dg.exp' to compile and run the test program. A typical `gcov' +test contains the following DejaGnu commands within comments: + + { dg-options "-fprofile-arcs -ftest-coverage" } + { dg-do run { target native } } + { dg-final { run-gcov sourcefile } } + + Checks of `gcov' output can include line counts, branch percentages, +and call return percentages. All of these checks are requested via +commands that appear in comments in the test's source file. Commands +to check line counts are processed by default. Commands to check +branch percentages and call return percentages are processed if the +`run-gcov' command has arguments `branches' or `calls', respectively. +For example, the following specifies checking both, as well as passing +`-b' to `gcov': + + { dg-final { run-gcov branches calls { -b sourcefile } } } + + A line count command appears within a comment on the source line that +is expected to get the specified count and has the form `count(CNT)'. +A test should only check line counts for lines that will get the same +count for any architecture. + + Commands to check branch percentages (`branch') and call return +percentages (`returns') are very similar to each other. A beginning +command appears on or before the first of a range of lines that will +report the percentage, and the ending command follows that range of +lines. The beginning command can include a list of percentages, all of +which are expected to be found within the range. A range is terminated +by the next command of the same kind. A command `branch(end)' or +`returns(end)' marks the end of a range without starting a new one. +For example: + + if (i > 10 && j > i && j < 20) /* branch(27 50 75) */ + /* branch(end) */ + foo (i, j); + + For a call return percentage, the value specified is the percentage of +calls reported to return. For a branch percentage, the value is either +the expected percentage or 100 minus that value, since the direction of +a branch can differ depending on the target or the optimization level. + + Not all branches and calls need to be checked. A test should not +check for branches that might be optimized away or replaced with +predicated instructions. Don't check for calls inserted by the +compiler or ones that might be inlined or optimized away. + + A single test can check for combinations of line counts, branch +percentages, and call return percentages. The command to check a line +count must appear on the line that will report that count, but commands +to check branch percentages and call return percentages can bracket the +lines that report them. + + +File: gccint.info, Node: profopt Testing, Next: compat Testing, Prev: gcov Testing, Up: Testsuites + +7.8 Support for testing profile-directed optimizations +====================================================== + +The file `profopt.exp' provides language-independent support for +checking correct execution of a test built with profile-directed +optimization. This testing requires that a test program be built and +executed twice. The first time it is compiled to generate profile +data, and the second time it is compiled to use the data that was +generated during the first execution. The second execution is to +verify that the test produces the expected results. + + To check that the optimization actually generated better code, a test +can be built and run a third time with normal optimizations to verify +that the performance is better with the profile-directed optimizations. +`profopt.exp' has the beginnings of this kind of support. + + `profopt.exp' provides generic support for profile-directed +optimizations. Each set of tests that uses it provides information +about a specific optimization: + +`tool' + tool being tested, e.g., `gcc' + +`profile_option' + options used to generate profile data + +`feedback_option' + options used to optimize using that profile data + +`prof_ext' + suffix of profile data files + +`PROFOPT_OPTIONS' + list of options with which to run each test, similar to the lists + for torture tests + +`{ dg-final-generate { LOCAL-DIRECTIVE } }' + This directive is similar to `dg-final', but the LOCAL-DIRECTIVE + is run after the generation of profile data. + +`{ dg-final-use { LOCAL-DIRECTIVE } }' + The LOCAL-DIRECTIVE is run after the profile data have been used. + + +File: gccint.info, Node: compat Testing, Next: Torture Tests, Prev: profopt Testing, Up: Testsuites + +7.9 Support for testing binary compatibility +============================================ + +The file `compat.exp' provides language-independent support for binary +compatibility testing. It supports testing interoperability of two +compilers that follow the same ABI, or of multiple sets of compiler +options that should not affect binary compatibility. It is intended to +be used for testsuites that complement ABI testsuites. + + A test supported by this framework has three parts, each in a separate +source file: a main program and two pieces that interact with each +other to split up the functionality being tested. + +`TESTNAME_main.SUFFIX' + Contains the main program, which calls a function in file + `TESTNAME_x.SUFFIX'. + +`TESTNAME_x.SUFFIX' + Contains at least one call to a function in `TESTNAME_y.SUFFIX'. + +`TESTNAME_y.SUFFIX' + Shares data with, or gets arguments from, `TESTNAME_x.SUFFIX'. + + Within each test, the main program and one functional piece are +compiled by the GCC under test. The other piece can be compiled by an +alternate compiler. If no alternate compiler is specified, then all +three source files are all compiled by the GCC under test. You can +specify pairs of sets of compiler options. The first element of such a +pair specifies options used with the GCC under test, and the second +element of the pair specifies options used with the alternate compiler. +Each test is compiled with each pair of options. + + `compat.exp' defines default pairs of compiler options. These can be +overridden by defining the environment variable `COMPAT_OPTIONS' as: + + COMPAT_OPTIONS="[list [list {TST1} {ALT1}] + ...[list {TSTN} {ALTN}]]" + + where TSTI and ALTI are lists of options, with TSTI used by the +compiler under test and ALTI used by the alternate compiler. For +example, with `[list [list {-g -O0} {-O3}] [list {-fpic} {-fPIC -O2}]]', +the test is first built with `-g -O0' by the compiler under test and +with `-O3' by the alternate compiler. The test is built a second time +using `-fpic' by the compiler under test and `-fPIC -O2' by the +alternate compiler. + + An alternate compiler is specified by defining an environment variable +to be the full pathname of an installed compiler; for C define +`ALT_CC_UNDER_TEST', and for C++ define `ALT_CXX_UNDER_TEST'. These +will be written to the `site.exp' file used by DejaGnu. The default is +to build each test with the compiler under test using the first of each +pair of compiler options from `COMPAT_OPTIONS'. When +`ALT_CC_UNDER_TEST' or `ALT_CXX_UNDER_TEST' is `same', each test is +built using the compiler under test but with combinations of the +options from `COMPAT_OPTIONS'. + + To run only the C++ compatibility suite using the compiler under test +and another version of GCC using specific compiler options, do the +following from `OBJDIR/gcc': + + rm site.exp + make -k \ + ALT_CXX_UNDER_TEST=${alt_prefix}/bin/g++ \ + COMPAT_OPTIONS="LISTS AS SHOWN ABOVE" \ + check-c++ \ + RUNTESTFLAGS="compat.exp" + + A test that fails when the source files are compiled with different +compilers, but passes when the files are compiled with the same +compiler, demonstrates incompatibility of the generated code or runtime +support. A test that fails for the alternate compiler but passes for +the compiler under test probably tests for a bug that was fixed in the +compiler under test but is present in the alternate compiler. + + The binary compatibility tests support a small number of test framework +commands that appear within comments in a test file. + +`dg-require-*' + These commands can be used in `TESTNAME_main.SUFFIX' to skip the + test if specific support is not available on the target. + +`dg-options' + The specified options are used for compiling this particular source + file, appended to the options from `COMPAT_OPTIONS'. When this + command appears in `TESTNAME_main.SUFFIX' the options are also + used to link the test program. + +`dg-xfail-if' + This command can be used in a secondary source file to specify that + compilation is expected to fail for particular options on + particular targets. + + +File: gccint.info, Node: Torture Tests, Prev: compat Testing, Up: Testsuites + +7.10 Support for torture testing using multiple options +======================================================= + +Throughout the compiler testsuite there are several directories whose +tests are run multiple times, each with a different set of options. +These are known as torture tests. `lib/torture-options.exp' defines +procedures to set up these lists: + +`torture-init' + Initialize use of torture lists. + +`set-torture-options' + Set lists of torture options to use for tests with and without + loops. Optionally combine a set of torture options with a set of + other options, as is done with Objective-C runtime options. + +`torture-finish' + Finalize use of torture lists. + + The `.exp' file for a set of tests that use torture options must +include calls to these three procedures if: + + * It calls `gcc-dg-runtest' and overrides DG_TORTURE_OPTIONS. + + * It calls ${TOOL}`-torture' or ${TOOL}`-torture-execute', where + TOOL is `c', `fortran', or `objc'. + + * It calls `dg-pch'. + + It is not necessary for a `.exp' file that calls `gcc-dg-runtest' to +call the torture procedures if the tests should use the list in +DG_TORTURE_OPTIONS defined in `gcc-dg.exp'. + + Most uses of torture options can override the default lists by defining +TORTURE_OPTIONS or add to the default list by defining +ADDITIONAL_TORTURE_OPTIONS. Define these in a `.dejagnurc' file or add +them to the `site.exp' file; for example + + set ADDITIONAL_TORTURE_OPTIONS [list \ + { -O2 -ftree-loop-linear } \ + { -O2 -fpeel-loops } ] + + +File: gccint.info, Node: Options, Next: Passes, Prev: Testsuites, Up: Top + +8 Option specification files +**************************** + +Most GCC command-line options are described by special option +definition files, the names of which conventionally end in `.opt'. +This chapter describes the format of these files. + +* Menu: + +* Option file format:: The general layout of the files +* Option properties:: Supported option properties + + +File: gccint.info, Node: Option file format, Next: Option properties, Up: Options + +8.1 Option file format +====================== + +Option files are a simple list of records in which each field occupies +its own line and in which the records themselves are separated by blank +lines. Comments may appear on their own line anywhere within the file +and are preceded by semicolons. Whitespace is allowed before the +semicolon. + + The files can contain the following types of record: + + * A language definition record. These records have two fields: the + string `Language' and the name of the language. Once a language + has been declared in this way, it can be used as an option + property. *Note Option properties::. + + * A target specific save record to save additional information. These + records have two fields: the string `TargetSave', and a + declaration type to go in the `cl_target_option' structure. + + * A variable record to define a variable used to store option + information. These records have two fields: the string + `Variable', and a declaration of the type and name of the + variable, optionally with an initializer (but without any trailing + `;'). These records may be used for variables used for many + options where declaring the initializer in a single option + definition record, or duplicating it in many records, would be + inappropriate, or for variables set in option handlers rather than + referenced by `Var' properties. + + * A variable record to define a variable used to store option + information. These records have two fields: the string + `TargetVariable', and a declaration of the type and name of the + variable, optionally with an initializer (but without any trailing + `;'). `TargetVariable' is a combination of `Variable' and + `TargetSave' records in that the variable is defined in the + `gcc_options' structure, but these variables are also stored in + the `cl_target_option' structure. The variables are saved in the + target save code and restored in the target restore code. + + * A variable record to record any additional files that the + `options.h' file should include. This is useful to provide + enumeration or structure definitions needed for target variables. + These records have two fields: the string `HeaderInclude' and the + name of the include file. + + * A variable record to record any additional files that the + `options.c' file should include. This is useful to provide inline + functions needed for target variables and/or `#ifdef' sequences to + properly set up the initialization. These records have two + fields: the string `SourceInclude' and the name of the include + file. + + * An enumeration record to define a set of strings that may be used + as arguments to an option or options. These records have three + fields: the string `Enum', a space-separated list of properties + and help text used to describe the set of strings in `--help' + output. Properties use the same format as option properties; the + following are valid: + `Name(NAME)' + This property is required; NAME must be a name (suitable for + use in C identifiers) used to identify the set of strings in + `Enum' option properties. + + `Type(TYPE)' + This property is required; TYPE is the C type for variables + set by options using this enumeration together with `Var'. + + `UnknownError(MESSAGE)' + The message MESSAGE will be used as an error message if the + argument is invalid; for enumerations without `UnknownError', + a generic error message is used. MESSAGE should contain a + single `%qs' format, which will be used to format the invalid + argument. + + * An enumeration value record to define one of the strings in a set + given in an `Enum' record. These records have two fields: the + string `EnumValue' and a space-separated list of properties. + Properties use the same format as option properties; the following + are valid: + `Enum(NAME)' + This property is required; NAME says which `Enum' record this + `EnumValue' record corresponds to. + + `String(STRING)' + This property is required; STRING is the string option + argument being described by this record. + + `Value(VALUE)' + This property is required; it says what value (representable + as `int') should be used for the given string. + + `Canonical' + This property is optional. If present, it says the present + string is the canonical one among all those with the given + value. Other strings yielding that value will be mapped to + this one so specs do not need to handle them. + + `DriverOnly' + This property is optional. If present, the present string + will only be accepted by the driver. This is used for cases + such as `-march=native' that are processed by the driver so + that `gcc -v' shows how the options chosen depended on the + system on which the compiler was run. + + * An option definition record. These records have the following + fields: + 1. the name of the option, with the leading "-" removed + + 2. a space-separated list of option properties (*note Option + properties::) + + 3. the help text to use for `--help' (omitted if the second field + contains the `Undocumented' property). + + By default, all options beginning with "f", "W" or "m" are + implicitly assumed to take a "no-" form. This form should not be + listed separately. If an option beginning with one of these + letters does not have a "no-" form, you can use the + `RejectNegative' property to reject it. + + The help text is automatically line-wrapped before being displayed. + Normally the name of the option is printed on the left-hand side of + the output and the help text is printed on the right. However, if + the help text contains a tab character, the text to the left of + the tab is used instead of the option's name and the text to the + right of the tab forms the help text. This allows you to + elaborate on what type of argument the option takes. + + * A target mask record. These records have one field of the form + `Mask(X)'. The options-processing script will automatically + allocate a bit in `target_flags' (*note Run-time Target::) for + each mask name X and set the macro `MASK_X' to the appropriate + bitmask. It will also declare a `TARGET_X' macro that has the + value 1 when bit `MASK_X' is set and 0 otherwise. + + They are primarily intended to declare target masks that are not + associated with user options, either because these masks represent + internal switches or because the options are not available on all + configurations and yet the masks always need to be defined. + + +File: gccint.info, Node: Option properties, Prev: Option file format, Up: Options + +8.2 Option properties +===================== + +The second field of an option record can specify any of the following +properties. When an option takes an argument, it is enclosed in +parentheses following the option property name. The parser that +handles option files is quite simplistic, and will be tricked by any +nested parentheses within the argument text itself; in this case, the +entire option argument can be wrapped in curly braces within the +parentheses to demarcate it, e.g.: + + Condition({defined (USE_CYGWIN_LIBSTDCXX_WRAPPERS)}) + +`Common' + The option is available for all languages and targets. + +`Target' + The option is available for all languages but is target-specific. + +`Driver' + The option is handled by the compiler driver using code not shared + with the compilers proper (`cc1' etc.). + +`LANGUAGE' + The option is available when compiling for the given language. + + It is possible to specify several different languages for the same + option. Each LANGUAGE must have been declared by an earlier + `Language' record. *Note Option file format::. + +`RejectDriver' + The option is only handled by the compilers proper (`cc1' etc.) + and should not be accepted by the driver. + +`RejectNegative' + The option does not have a "no-" form. All options beginning with + "f", "W" or "m" are assumed to have a "no-" form unless this + property is used. + +`Negative(OTHERNAME)' + The option will turn off another option OTHERNAME, which is the + option name with the leading "-" removed. This chain action will + propagate through the `Negative' property of the option to be + turned off. + +`Joined' +`Separate' + The option takes a mandatory argument. `Joined' indicates that + the option and argument can be included in the same `argv' entry + (as with `-mflush-func=NAME', for example). `Separate' indicates + that the option and argument can be separate `argv' entries (as + with `-o'). An option is allowed to have both of these properties. + +`JoinedOrMissing' + The option takes an optional argument. If the argument is given, + it will be part of the same `argv' entry as the option itself. + + This property cannot be used alongside `Joined' or `Separate'. + +`MissingArgError(MESSAGE)' + For an option marked `Joined' or `Separate', the message MESSAGE + will be used as an error message if the mandatory argument is + missing; for options without `MissingArgError', a generic error + message is used. MESSAGE should contain a single `%qs' format, + which will be used to format the name of the option passed. + +`Args(N)' + For an option marked `Separate', indicate that it takes N + arguments. The default is 1. + +`UInteger' + The option's argument is a non-negative integer. The option parser + will check and convert the argument before passing it to the + relevant option handler. `UInteger' should also be used on + options like `-falign-loops' where both `-falign-loops' and + `-falign-loops'=N are supported to make sure the saved options are + given a full integer. + +`NoDriverArg' + For an option marked `Separate', the option only takes an argument + in the compiler proper, not in the driver. This is for + compatibility with existing options that are used both directly and + via `-Wp,'; new options should not have this property. + +`Var(VAR)' + The state of this option should be stored in variable VAR + (actually a macro for `global_options.x_VAR'). The way that the + state is stored depends on the type of option: + + * If the option uses the `Mask' or `InverseMask' properties, + VAR is the integer variable that contains the mask. + + * If the option is a normal on/off switch, VAR is an integer + variable that is nonzero when the option is enabled. The + options parser will set the variable to 1 when the positive + form of the option is used and 0 when the "no-" form is used. + + * If the option takes an argument and has the `UInteger' + property, VAR is an integer variable that stores the value of + the argument. + + * If the option takes an argument and has the `Enum' property, + VAR is a variable (type given in the `Type' property of the + `Enum' record whose `Name' property has the same argument as + the `Enum' property of this option) that stores the value of + the argument. + + * If the option has the `Defer' property, VAR is a pointer to a + `VEC(cl_deferred_option,heap)' that stores the option for + later processing. (VAR is declared with type `void *' and + needs to be cast to `VEC(cl_deferred_option,heap)' before + use.) + + * Otherwise, if the option takes an argument, VAR is a pointer + to the argument string. The pointer will be null if the + argument is optional and wasn't given. + + The option-processing script will usually zero-initialize VAR. + You can modify this behavior using `Init'. + +`Var(VAR, SET)' + The option controls an integer variable VAR and is active when VAR + equals SET. The option parser will set VAR to SET when the + positive form of the option is used and `!SET' when the "no-" form + is used. + + VAR is declared in the same way as for the single-argument form + described above. + +`Init(VALUE)' + The variable specified by the `Var' property should be statically + initialized to VALUE. If more than one option using the same + variable specifies `Init', all must specify the same initializer. + +`Mask(NAME)' + The option is associated with a bit in the `target_flags' variable + (*note Run-time Target::) and is active when that bit is set. You + may also specify `Var' to select a variable other than + `target_flags'. + + The options-processing script will automatically allocate a unique + bit for the option. If the option is attached to `target_flags', + the script will set the macro `MASK_NAME' to the appropriate + bitmask. It will also declare a `TARGET_NAME' macro that has the + value 1 when the option is active and 0 otherwise. If you use + `Var' to attach the option to a different variable, the associated + macros are called `OPTION_MASK_NAME' and `OPTION_NAME' + respectively. + + You can disable automatic bit allocation using `MaskExists'. + +`InverseMask(OTHERNAME)' +`InverseMask(OTHERNAME, THISNAME)' + The option is the inverse of another option that has the + `Mask(OTHERNAME)' property. If THISNAME is given, the + options-processing script will declare a `TARGET_THISNAME' macro + that is 1 when the option is active and 0 otherwise. + +`MaskExists' + The mask specified by the `Mask' property already exists. No + `MASK' or `TARGET' definitions should be added to `options.h' in + response to this option record. + + The main purpose of this property is to support synonymous options. + The first option should use `Mask(NAME)' and the others should use + `Mask(NAME) MaskExists'. + +`Enum(NAME)' + The option's argument is a string from the set of strings + associated with the corresponding `Enum' record. The string is + checked and converted to the integer specified in the corresponding + `EnumValue' record before being passed to option handlers. + +`Defer' + The option should be stored in a vector, specified with `Var', for + later processing. + +`Alias(OPT)' +`Alias(OPT, ARG)' +`Alias(OPT, POSARG, NEGARG)' + The option is an alias for `-OPT'. In the first form, any + argument passed to the alias is considered to be passed to `-OPT', + and `-OPT' is considered to be negated if the alias is used in + negated form. In the second form, the alias may not be negated or + have an argument, and POSARG is considered to be passed as an + argument to `-OPT'. In the third form, the alias may not have an + argument, if the alias is used in the positive form then POSARG is + considered to be passed to `-OPT', and if the alias is used in the + negative form then NEGARG is considered to be passed to `-OPT'. + + Aliases should not specify `Var' or `Mask' or `UInteger'. Aliases + should normally specify the same languages as the target of the + alias; the flags on the target will be used to determine any + diagnostic for use of an option for the wrong language, while + those on the alias will be used to identify what command-line text + is the option and what text is any argument to that option. + + When an `Alias' definition is used for an option, driver specs do + not need to handle it and no `OPT_' enumeration value is defined + for it; only the canonical form of the option will be seen in those + places. + +`Ignore' + This option is ignored apart from printing any warning specified + using `Warn'. The option will not be seen by specs and no `OPT_' + enumeration value is defined for it. + +`SeparateAlias' + For an option marked with `Joined', `Separate' and `Alias', the + option only acts as an alias when passed a separate argument; with + a joined argument it acts as a normal option, with an `OPT_' + enumeration value. This is for compatibility with the Java `-d' + option and should not be used for new options. + +`Warn(MESSAGE)' + If this option is used, output the warning MESSAGE. MESSAGE is a + format string, either taking a single operand with a `%qs' format + which is the option name, or not taking any operands, which is + passed to the `warning' function. If an alias is marked `Warn', + the target of the alias must not also be marked `Warn'. + +`Report' + The state of the option should be printed by `-fverbose-asm'. + +`Warning' + This is a warning option and should be shown as such in `--help' + output. This flag does not currently affect anything other than + `--help'. + +`Optimization' + This is an optimization option. It should be shown as such in + `--help' output, and any associated variable named using `Var' + should be saved and restored when the optimization level is + changed with `optimize' attributes. + +`Undocumented' + The option is deliberately missing documentation and should not be + included in the `--help' output. + +`Condition(COND)' + The option should only be accepted if preprocessor condition COND + is true. Note that any C declarations associated with the option + will be present even if COND is false; COND simply controls + whether the option is accepted and whether it is printed in the + `--help' output. + +`Save' + Build the `cl_target_option' structure to hold a copy of the + option, add the functions `cl_target_option_save' and + `cl_target_option_restore' to save and restore the options. + +`SetByCombined' + The option may also be set by a combined option such as + `-ffast-math'. This causes the `gcc_options' struct to have a + field `frontend_set_NAME', where `NAME' is the name of the field + holding the value of this option (without the leading `x_'). This + gives the front end a way to indicate that the value has been set + explicitly and should not be changed by the combined option. For + example, some front ends use this to prevent `-ffast-math' and + `-fno-fast-math' from changing the value of `-fmath-errno' for + languages that do not use `errno'. + + + +File: gccint.info, Node: Passes, Next: GENERIC, Prev: Options, Up: Top + +9 Passes and Files of the Compiler +********************************** + +This chapter is dedicated to giving an overview of the optimization and +code generation passes of the compiler. In the process, it describes +some of the language front end interface, though this description is no +where near complete. + +* Menu: + +* Parsing pass:: The language front end turns text into bits. +* Gimplification pass:: The bits are turned into something we can optimize. +* Pass manager:: Sequencing the optimization passes. +* Tree SSA passes:: Optimizations on a high-level representation. +* RTL passes:: Optimizations on a low-level representation. + + +File: gccint.info, Node: Parsing pass, Next: Gimplification pass, Up: Passes + +9.1 Parsing pass +================ + +The language front end is invoked only once, via +`lang_hooks.parse_file', to parse the entire input. The language front +end may use any intermediate language representation deemed +appropriate. The C front end uses GENERIC trees (*note GENERIC::), plus +a double handful of language specific tree codes defined in +`c-common.def'. The Fortran front end uses a completely different +private representation. + + At some point the front end must translate the representation used in +the front end to a representation understood by the language-independent +portions of the compiler. Current practice takes one of two forms. +The C front end manually invokes the gimplifier (*note GIMPLE::) on +each function, and uses the gimplifier callbacks to convert the +language-specific tree nodes directly to GIMPLE before passing the +function off to be compiled. The Fortran front end converts from a +private representation to GENERIC, which is later lowered to GIMPLE +when the function is compiled. Which route to choose probably depends +on how well GENERIC (plus extensions) can be made to match up with the +source language and necessary parsing data structures. + + BUG: Gimplification must occur before nested function lowering, and +nested function lowering must be done by the front end before passing +the data off to cgraph. + + TODO: Cgraph should control nested function lowering. It would only +be invoked when it is certain that the outer-most function is used. + + TODO: Cgraph needs a gimplify_function callback. It should be invoked +when (1) it is certain that the function is used, (2) warning flags +specified by the user require some amount of compilation in order to +honor, (3) the language indicates that semantic analysis is not +complete until gimplification occurs. Hum... this sounds overly +complicated. Perhaps we should just have the front end gimplify +always; in most cases it's only one function call. + + The front end needs to pass all function definitions and top level +declarations off to the middle-end so that they can be compiled and +emitted to the object file. For a simple procedural language, it is +usually most convenient to do this as each top level declaration or +definition is seen. There is also a distinction to be made between +generating functional code and generating complete debug information. +The only thing that is absolutely required for functional code is that +function and data _definitions_ be passed to the middle-end. For +complete debug information, function, data and type declarations should +all be passed as well. + + In any case, the front end needs each complete top-level function or +data declaration, and each data definition should be passed to +`rest_of_decl_compilation'. Each complete type definition should be +passed to `rest_of_type_compilation'. Each function definition should +be passed to `cgraph_finalize_function'. + + TODO: I know rest_of_compilation currently has all sorts of RTL +generation semantics. I plan to move all code generation bits (both +Tree and RTL) to compile_function. Should we hide cgraph from the +front ends and move back to rest_of_compilation as the official +interface? Possibly we should rename all three interfaces such that +the names match in some meaningful way and that is more descriptive +than "rest_of". + + The middle-end will, at its option, emit the function and data +definitions immediately or queue them for later processing. + + +File: gccint.info, Node: Gimplification pass, Next: Pass manager, Prev: Parsing pass, Up: Passes + +9.2 Gimplification pass +======================= + +"Gimplification" is a whimsical term for the process of converting the +intermediate representation of a function into the GIMPLE language +(*note GIMPLE::). The term stuck, and so words like "gimplification", +"gimplify", "gimplifier" and the like are sprinkled throughout this +section of code. + + While a front end may certainly choose to generate GIMPLE directly if +it chooses, this can be a moderately complex process unless the +intermediate language used by the front end is already fairly simple. +Usually it is easier to generate GENERIC trees plus extensions and let +the language-independent gimplifier do most of the work. + + The main entry point to this pass is `gimplify_function_tree' located +in `gimplify.c'. From here we process the entire function gimplifying +each statement in turn. The main workhorse for this pass is +`gimplify_expr'. Approximately everything passes through here at least +once, and it is from here that we invoke the `lang_hooks.gimplify_expr' +callback. + + The callback should examine the expression in question and return +`GS_UNHANDLED' if the expression is not a language specific construct +that requires attention. Otherwise it should alter the expression in +some way to such that forward progress is made toward producing valid +GIMPLE. If the callback is certain that the transformation is complete +and the expression is valid GIMPLE, it should return `GS_ALL_DONE'. +Otherwise it should return `GS_OK', which will cause the expression to +be processed again. If the callback encounters an error during the +transformation (because the front end is relying on the gimplification +process to finish semantic checks), it should return `GS_ERROR'. + + +File: gccint.info, Node: Pass manager, Next: Tree SSA passes, Prev: Gimplification pass, Up: Passes + +9.3 Pass manager +================ + +The pass manager is located in `passes.c', `tree-optimize.c' and +`tree-pass.h'. Its job is to run all of the individual passes in the +correct order, and take care of standard bookkeeping that applies to +every pass. + + The theory of operation is that each pass defines a structure that +represents everything we need to know about that pass--when it should +be run, how it should be run, what intermediate language form or +on-the-side data structures it needs. We register the pass to be run +in some particular order, and the pass manager arranges for everything +to happen in the correct order. + + The actuality doesn't completely live up to the theory at present. +Command-line switches and `timevar_id_t' enumerations must still be +defined elsewhere. The pass manager validates constraints but does not +attempt to (re-)generate data structures or lower intermediate language +form based on the requirements of the next pass. Nevertheless, what is +present is useful, and a far sight better than nothing at all. + + Each pass should have a unique name. Each pass may have its own dump +file (for GCC debugging purposes). Passes with a name starting with a +star do not dump anything. Sometimes passes are supposed to share a +dump file / option name. To still give these unique names, you can use +a prefix that is delimited by a space from the part that is used for +the dump file / option name. E.g. When the pass name is "ud dce", the +name used for dump file/options is "dce". + + TODO: describe the global variables set up by the pass manager, and a +brief description of how a new pass should use it. I need to look at +what info RTL passes use first... + + +File: gccint.info, Node: Tree SSA passes, Next: RTL passes, Prev: Pass manager, Up: Passes + +9.4 Tree SSA passes +=================== + +The following briefly describes the Tree optimization passes that are +run after gimplification and what source files they are located in. + + * Remove useless statements + + This pass is an extremely simple sweep across the gimple code in + which we identify obviously dead code and remove it. Here we do + things like simplify `if' statements with constant conditions, + remove exception handling constructs surrounding code that + obviously cannot throw, remove lexical bindings that contain no + variables, and other assorted simplistic cleanups. The idea is to + get rid of the obvious stuff quickly rather than wait until later + when it's more work to get rid of it. This pass is located in + `tree-cfg.c' and described by `pass_remove_useless_stmts'. + + * Mudflap declaration registration + + If mudflap (*note -fmudflap -fmudflapth -fmudflapir: (gcc)Optimize + Options.) is enabled, we generate code to register some variable + declarations with the mudflap runtime. Specifically, the runtime + tracks the lifetimes of those variable declarations that have + their addresses taken, or whose bounds are unknown at compile time + (`extern'). This pass generates new exception handling constructs + (`try'/`finally'), and so must run before those are lowered. In + addition, the pass enqueues declarations of static variables whose + lifetimes extend to the entire program. The pass is located in + `tree-mudflap.c' and is described by `pass_mudflap_1'. + + * OpenMP lowering + + If OpenMP generation (`-fopenmp') is enabled, this pass lowers + OpenMP constructs into GIMPLE. + + Lowering of OpenMP constructs involves creating replacement + expressions for local variables that have been mapped using data + sharing clauses, exposing the control flow of most synchronization + directives and adding region markers to facilitate the creation of + the control flow graph. The pass is located in `omp-low.c' and is + described by `pass_lower_omp'. + + * OpenMP expansion + + If OpenMP generation (`-fopenmp') is enabled, this pass expands + parallel regions into their own functions to be invoked by the + thread library. The pass is located in `omp-low.c' and is + described by `pass_expand_omp'. + + * Lower control flow + + This pass flattens `if' statements (`COND_EXPR') and moves lexical + bindings (`BIND_EXPR') out of line. After this pass, all `if' + statements will have exactly two `goto' statements in its `then' + and `else' arms. Lexical binding information for each statement + will be found in `TREE_BLOCK' rather than being inferred from its + position under a `BIND_EXPR'. This pass is found in + `gimple-low.c' and is described by `pass_lower_cf'. + + * Lower exception handling control flow + + This pass decomposes high-level exception handling constructs + (`TRY_FINALLY_EXPR' and `TRY_CATCH_EXPR') into a form that + explicitly represents the control flow involved. After this pass, + `lookup_stmt_eh_region' will return a non-negative number for any + statement that may have EH control flow semantics; examine + `tree_can_throw_internal' or `tree_can_throw_external' for exact + semantics. Exact control flow may be extracted from + `foreach_reachable_handler'. The EH region nesting tree is defined + in `except.h' and built in `except.c'. The lowering pass itself + is in `tree-eh.c' and is described by `pass_lower_eh'. + + * Build the control flow graph + + This pass decomposes a function into basic blocks and creates all + of the edges that connect them. It is located in `tree-cfg.c' and + is described by `pass_build_cfg'. + + * Find all referenced variables + + This pass walks the entire function and collects an array of all + variables referenced in the function, `referenced_vars'. The + index at which a variable is found in the array is used as a UID + for the variable within this function. This data is needed by the + SSA rewriting routines. The pass is located in `tree-dfa.c' and + is described by `pass_referenced_vars'. + + * Enter static single assignment form + + This pass rewrites the function such that it is in SSA form. After + this pass, all `is_gimple_reg' variables will be referenced by + `SSA_NAME', and all occurrences of other variables will be + annotated with `VDEFS' and `VUSES'; PHI nodes will have been + inserted as necessary for each basic block. This pass is located + in `tree-ssa.c' and is described by `pass_build_ssa'. + + * Warn for uninitialized variables + + This pass scans the function for uses of `SSA_NAME's that are fed + by default definition. For non-parameter variables, such uses are + uninitialized. The pass is run twice, before and after + optimization (if turned on). In the first pass we only warn for + uses that are positively uninitialized; in the second pass we warn + for uses that are possibly uninitialized. The pass is located in + `tree-ssa.c' and is defined by `pass_early_warn_uninitialized' and + `pass_late_warn_uninitialized'. + + * Dead code elimination + + This pass scans the function for statements without side effects + whose result is unused. It does not do memory life analysis, so + any value that is stored in memory is considered used. The pass + is run multiple times throughout the optimization process. It is + located in `tree-ssa-dce.c' and is described by `pass_dce'. + + * Dominator optimizations + + This pass performs trivial dominator-based copy and constant + propagation, expression simplification, and jump threading. It is + run multiple times throughout the optimization process. It is + located in `tree-ssa-dom.c' and is described by `pass_dominator'. + + * Forward propagation of single-use variables + + This pass attempts to remove redundant computation by substituting + variables that are used once into the expression that uses them and + seeing if the result can be simplified. It is located in + `tree-ssa-forwprop.c' and is described by `pass_forwprop'. + + * Copy Renaming + + This pass attempts to change the name of compiler temporaries + involved in copy operations such that SSA->normal can coalesce the + copy away. When compiler temporaries are copies of user + variables, it also renames the compiler temporary to the user + variable resulting in better use of user symbols. It is located + in `tree-ssa-copyrename.c' and is described by `pass_copyrename'. + + * PHI node optimizations + + This pass recognizes forms of PHI inputs that can be represented as + conditional expressions and rewrites them into straight line code. + It is located in `tree-ssa-phiopt.c' and is described by + `pass_phiopt'. + + * May-alias optimization + + This pass performs a flow sensitive SSA-based points-to analysis. + The resulting may-alias, must-alias, and escape analysis + information is used to promote variables from in-memory + addressable objects to non-aliased variables that can be renamed + into SSA form. We also update the `VDEF'/`VUSE' memory tags for + non-renameable aggregates so that we get fewer false kills. The + pass is located in `tree-ssa-alias.c' and is described by + `pass_may_alias'. + + Interprocedural points-to information is located in + `tree-ssa-structalias.c' and described by `pass_ipa_pta'. + + * Profiling + + This pass rewrites the function in order to collect runtime block + and value profiling data. Such data may be fed back into the + compiler on a subsequent run so as to allow optimization based on + expected execution frequencies. The pass is located in + `predict.c' and is described by `pass_profile'. + + * Lower complex arithmetic + + This pass rewrites complex arithmetic operations into their + component scalar arithmetic operations. The pass is located in + `tree-complex.c' and is described by `pass_lower_complex'. + + * Scalar replacement of aggregates + + This pass rewrites suitable non-aliased local aggregate variables + into a set of scalar variables. The resulting scalar variables are + rewritten into SSA form, which allows subsequent optimization + passes to do a significantly better job with them. The pass is + located in `tree-sra.c' and is described by `pass_sra'. + + * Dead store elimination + + This pass eliminates stores to memory that are subsequently + overwritten by another store, without any intervening loads. The + pass is located in `tree-ssa-dse.c' and is described by `pass_dse'. + + * Tail recursion elimination + + This pass transforms tail recursion into a loop. It is located in + `tree-tailcall.c' and is described by `pass_tail_recursion'. + + * Forward store motion + + This pass sinks stores and assignments down the flowgraph closer + to their use point. The pass is located in `tree-ssa-sink.c' and + is described by `pass_sink_code'. + + * Partial redundancy elimination + + This pass eliminates partially redundant computations, as well as + performing load motion. The pass is located in `tree-ssa-pre.c' + and is described by `pass_pre'. + + Just before partial redundancy elimination, if + `-funsafe-math-optimizations' is on, GCC tries to convert + divisions to multiplications by the reciprocal. The pass is + located in `tree-ssa-math-opts.c' and is described by + `pass_cse_reciprocal'. + + * Full redundancy elimination + + This is a simpler form of PRE that only eliminates redundancies + that occur an all paths. It is located in `tree-ssa-pre.c' and + described by `pass_fre'. + + * Loop optimization + + The main driver of the pass is placed in `tree-ssa-loop.c' and + described by `pass_loop'. + + The optimizations performed by this pass are: + + Loop invariant motion. This pass moves only invariants that would + be hard to handle on RTL level (function calls, operations that + expand to nontrivial sequences of insns). With `-funswitch-loops' + it also moves operands of conditions that are invariant out of the + loop, so that we can use just trivial invariantness analysis in + loop unswitching. The pass also includes store motion. The pass + is implemented in `tree-ssa-loop-im.c'. + + Canonical induction variable creation. This pass creates a simple + counter for number of iterations of the loop and replaces the exit + condition of the loop using it, in case when a complicated + analysis is necessary to determine the number of iterations. + Later optimizations then may determine the number easily. The + pass is implemented in `tree-ssa-loop-ivcanon.c'. + + Induction variable optimizations. This pass performs standard + induction variable optimizations, including strength reduction, + induction variable merging and induction variable elimination. + The pass is implemented in `tree-ssa-loop-ivopts.c'. + + Loop unswitching. This pass moves the conditional jumps that are + invariant out of the loops. To achieve this, a duplicate of the + loop is created for each possible outcome of conditional jump(s). + The pass is implemented in `tree-ssa-loop-unswitch.c'. This pass + should eventually replace the RTL level loop unswitching in + `loop-unswitch.c', but currently the RTL level pass is not + completely redundant yet due to deficiencies in tree level alias + analysis. + + The optimizations also use various utility functions contained in + `tree-ssa-loop-manip.c', `cfgloop.c', `cfgloopanal.c' and + `cfgloopmanip.c'. + + Vectorization. This pass transforms loops to operate on vector + types instead of scalar types. Data parallelism across loop + iterations is exploited to group data elements from consecutive + iterations into a vector and operate on them in parallel. + Depending on available target support the loop is conceptually + unrolled by a factor `VF' (vectorization factor), which is the + number of elements operated upon in parallel in each iteration, + and the `VF' copies of each scalar operation are fused to form a + vector operation. Additional loop transformations such as peeling + and versioning may take place to align the number of iterations, + and to align the memory accesses in the loop. The pass is + implemented in `tree-vectorizer.c' (the main driver), + `tree-vect-loop.c' and `tree-vect-loop-manip.c' (loop specific + parts and general loop utilities), `tree-vect-slp' (loop-aware SLP + functionality), `tree-vect-stmts.c' and `tree-vect-data-refs.c'. + Analysis of data references is in `tree-data-ref.c'. + + SLP Vectorization. This pass performs vectorization of + straight-line code. The pass is implemented in `tree-vectorizer.c' + (the main driver), `tree-vect-slp.c', `tree-vect-stmts.c' and + `tree-vect-data-refs.c'. + + Autoparallelization. This pass splits the loop iteration space to + run into several threads. The pass is implemented in + `tree-parloops.c'. + + Graphite is a loop transformation framework based on the polyhedral + model. Graphite stands for Gimple Represented as Polyhedra. The + internals of this infrastructure are documented in + `http://gcc.gnu.org/wiki/Graphite'. The passes working on this + representation are implemented in the various `graphite-*' files. + + * Tree level if-conversion for vectorizer + + This pass applies if-conversion to simple loops to help vectorizer. + We identify if convertible loops, if-convert statements and merge + basic blocks in one big block. The idea is to present loop in such + form so that vectorizer can have one to one mapping between + statements and available vector operations. This pass is located + in `tree-if-conv.c' and is described by `pass_if_conversion'. + + * Conditional constant propagation + + This pass relaxes a lattice of values in order to identify those + that must be constant even in the presence of conditional branches. + The pass is located in `tree-ssa-ccp.c' and is described by + `pass_ccp'. + + A related pass that works on memory loads and stores, and not just + register values, is located in `tree-ssa-ccp.c' and described by + `pass_store_ccp'. + + * Conditional copy propagation + + This is similar to constant propagation but the lattice of values + is the "copy-of" relation. It eliminates redundant copies from the + code. The pass is located in `tree-ssa-copy.c' and described by + `pass_copy_prop'. + + A related pass that works on memory copies, and not just register + copies, is located in `tree-ssa-copy.c' and described by + `pass_store_copy_prop'. + + * Value range propagation + + This transformation is similar to constant propagation but instead + of propagating single constant values, it propagates known value + ranges. The implementation is based on Patterson's range + propagation algorithm (Accurate Static Branch Prediction by Value + Range Propagation, J. R. C. Patterson, PLDI '95). In contrast to + Patterson's algorithm, this implementation does not propagate + branch probabilities nor it uses more than a single range per SSA + name. This means that the current implementation cannot be used + for branch prediction (though adapting it would not be difficult). + The pass is located in `tree-vrp.c' and is described by `pass_vrp'. + + * Folding built-in functions + + This pass simplifies built-in functions, as applicable, with + constant arguments or with inferable string lengths. It is + located in `tree-ssa-ccp.c' and is described by + `pass_fold_builtins'. + + * Split critical edges + + This pass identifies critical edges and inserts empty basic blocks + such that the edge is no longer critical. The pass is located in + `tree-cfg.c' and is described by `pass_split_crit_edges'. + + * Control dependence dead code elimination + + This pass is a stronger form of dead code elimination that can + eliminate unnecessary control flow statements. It is located in + `tree-ssa-dce.c' and is described by `pass_cd_dce'. + + * Tail call elimination + + This pass identifies function calls that may be rewritten into + jumps. No code transformation is actually applied here, but the + data and control flow problem is solved. The code transformation + requires target support, and so is delayed until RTL. In the + meantime `CALL_EXPR_TAILCALL' is set indicating the possibility. + The pass is located in `tree-tailcall.c' and is described by + `pass_tail_calls'. The RTL transformation is handled by + `fixup_tail_calls' in `calls.c'. + + * Warn for function return without value + + For non-void functions, this pass locates return statements that do + not specify a value and issues a warning. Such a statement may + have been injected by falling off the end of the function. This + pass is run last so that we have as much time as possible to prove + that the statement is not reachable. It is located in + `tree-cfg.c' and is described by `pass_warn_function_return'. + + * Mudflap statement annotation + + If mudflap is enabled, we rewrite some memory accesses with code to + validate that the memory access is correct. In particular, + expressions involving pointer dereferences (`INDIRECT_REF', + `ARRAY_REF', etc.) are replaced by code that checks the selected + address range against the mudflap runtime's database of valid + regions. This check includes an inline lookup into a + direct-mapped cache, based on shift/mask operations of the pointer + value, with a fallback function call into the runtime. The pass + is located in `tree-mudflap.c' and is described by + `pass_mudflap_2'. + + * Leave static single assignment form + + This pass rewrites the function such that it is in normal form. At + the same time, we eliminate as many single-use temporaries as + possible, so the intermediate language is no longer GIMPLE, but + GENERIC. The pass is located in `tree-outof-ssa.c' and is + described by `pass_del_ssa'. + + * Merge PHI nodes that feed into one another + + This is part of the CFG cleanup passes. It attempts to join PHI + nodes from a forwarder CFG block into another block with PHI + nodes. The pass is located in `tree-cfgcleanup.c' and is + described by `pass_merge_phi'. + + * Return value optimization + + If a function always returns the same local variable, and that + local variable is an aggregate type, then the variable is replaced + with the return value for the function (i.e., the function's + DECL_RESULT). This is equivalent to the C++ named return value + optimization applied to GIMPLE. The pass is located in + `tree-nrv.c' and is described by `pass_nrv'. + + * Return slot optimization + + If a function returns a memory object and is called as `var = + foo()', this pass tries to change the call so that the address of + `var' is sent to the caller to avoid an extra memory copy. This + pass is located in `tree-nrv.c' and is described by + `pass_return_slot'. + + * Optimize calls to `__builtin_object_size' + + This is a propagation pass similar to CCP that tries to remove + calls to `__builtin_object_size' when the size of the object can be + computed at compile-time. This pass is located in + `tree-object-size.c' and is described by `pass_object_sizes'. + + * Loop invariant motion + + This pass removes expensive loop-invariant computations out of + loops. The pass is located in `tree-ssa-loop.c' and described by + `pass_lim'. + + * Loop nest optimizations + + This is a family of loop transformations that works on loop nests. + It includes loop interchange, scaling, skewing and reversal and + they are all geared to the optimization of data locality in array + traversals and the removal of dependencies that hamper + optimizations such as loop parallelization and vectorization. The + pass is located in `tree-loop-linear.c' and described by + `pass_linear_transform'. + + * Removal of empty loops + + This pass removes loops with no code in them. The pass is located + in `tree-ssa-loop-ivcanon.c' and described by `pass_empty_loop'. + + * Unrolling of small loops + + This pass completely unrolls loops with few iterations. The pass + is located in `tree-ssa-loop-ivcanon.c' and described by + `pass_complete_unroll'. + + * Predictive commoning + + This pass makes the code reuse the computations from the previous + iterations of the loops, especially loads and stores to memory. + It does so by storing the values of these computations to a bank + of temporary variables that are rotated at the end of loop. To + avoid the need for this rotation, the loop is then unrolled and + the copies of the loop body are rewritten to use the appropriate + version of the temporary variable. This pass is located in + `tree-predcom.c' and described by `pass_predcom'. + + * Array prefetching + + This pass issues prefetch instructions for array references inside + loops. The pass is located in `tree-ssa-loop-prefetch.c' and + described by `pass_loop_prefetch'. + + * Reassociation + + This pass rewrites arithmetic expressions to enable optimizations + that operate on them, like redundancy elimination and + vectorization. The pass is located in `tree-ssa-reassoc.c' and + described by `pass_reassoc'. + + * Optimization of `stdarg' functions + + This pass tries to avoid the saving of register arguments into the + stack on entry to `stdarg' functions. If the function doesn't use + any `va_start' macros, no registers need to be saved. If + `va_start' macros are used, the `va_list' variables don't escape + the function, it is only necessary to save registers that will be + used in `va_arg' macros. For instance, if `va_arg' is only used + with integral types in the function, floating point registers + don't need to be saved. This pass is located in `tree-stdarg.c' + and described by `pass_stdarg'. + + + +File: gccint.info, Node: RTL passes, Prev: Tree SSA passes, Up: Passes + +9.5 RTL passes +============== + +The following briefly describes the RTL generation and optimization +passes that are run after the Tree optimization passes. + + * RTL generation + + The source files for RTL generation include `stmt.c', `calls.c', + `expr.c', `explow.c', `expmed.c', `function.c', `optabs.c' and + `emit-rtl.c'. Also, the file `insn-emit.c', generated from the + machine description by the program `genemit', is used in this + pass. The header file `expr.h' is used for communication within + this pass. + + The header files `insn-flags.h' and `insn-codes.h', generated from + the machine description by the programs `genflags' and `gencodes', + tell this pass which standard names are available for use and + which patterns correspond to them. + + * Generation of exception landing pads + + This pass generates the glue that handles communication between the + exception handling library routines and the exception handlers + within the function. Entry points in the function that are + invoked by the exception handling library are called "landing + pads". The code for this pass is located in `except.c'. + + * Control flow graph cleanup + + This pass removes unreachable code, simplifies jumps to next, + jumps to jump, jumps across jumps, etc. The pass is run multiple + times. For historical reasons, it is occasionally referred to as + the "jump optimization pass". The bulk of the code for this pass + is in `cfgcleanup.c', and there are support routines in `cfgrtl.c' + and `jump.c'. + + * Forward propagation of single-def values + + This pass attempts to remove redundant computation by substituting + variables that come from a single definition, and seeing if the + result can be simplified. It performs copy propagation and + addressing mode selection. The pass is run twice, with values + being propagated into loops only on the second run. The code is + located in `fwprop.c'. + + * Common subexpression elimination + + This pass removes redundant computation within basic blocks, and + optimizes addressing modes based on cost. The pass is run twice. + The code for this pass is located in `cse.c'. + + * Global common subexpression elimination + + This pass performs two different types of GCSE depending on + whether you are optimizing for size or not (LCM based GCSE tends + to increase code size for a gain in speed, while Morel-Renvoise + based GCSE does not). When optimizing for size, GCSE is done + using Morel-Renvoise Partial Redundancy Elimination, with the + exception that it does not try to move invariants out of + loops--that is left to the loop optimization pass. If MR PRE + GCSE is done, code hoisting (aka unification) is also done, as + well as load motion. If you are optimizing for speed, LCM (lazy + code motion) based GCSE is done. LCM is based on the work of + Knoop, Ruthing, and Steffen. LCM based GCSE also does loop + invariant code motion. We also perform load and store motion when + optimizing for speed. Regardless of which type of GCSE is used, + the GCSE pass also performs global constant and copy propagation. + The source file for this pass is `gcse.c', and the LCM routines + are in `lcm.c'. + + * Loop optimization + + This pass performs several loop related optimizations. The source + files `cfgloopanal.c' and `cfgloopmanip.c' contain generic loop + analysis and manipulation code. Initialization and finalization + of loop structures is handled by `loop-init.c'. A loop invariant + motion pass is implemented in `loop-invariant.c'. Basic block + level optimizations--unrolling, peeling and unswitching loops-- + are implemented in `loop-unswitch.c' and `loop-unroll.c'. + Replacing of the exit condition of loops by special + machine-dependent instructions is handled by `loop-doloop.c'. + + * Jump bypassing + + This pass is an aggressive form of GCSE that transforms the control + flow graph of a function by propagating constants into conditional + branch instructions. The source file for this pass is `gcse.c'. + + * If conversion + + This pass attempts to replace conditional branches and surrounding + assignments with arithmetic, boolean value producing comparison + instructions, and conditional move instructions. In the very last + invocation after reload, it will generate predicated instructions + when supported by the target. The code is located in `ifcvt.c'. + + * Web construction + + This pass splits independent uses of each pseudo-register. This + can improve effect of the other transformation, such as CSE or + register allocation. The code for this pass is located in `web.c'. + + * Instruction combination + + This pass attempts to combine groups of two or three instructions + that are related by data flow into single instructions. It + combines the RTL expressions for the instructions by substitution, + simplifies the result using algebra, and then attempts to match + the result against the machine description. The code is located + in `combine.c'. + + * Register movement + + This pass looks for cases where matching constraints would force an + instruction to need a reload, and this reload would be a + register-to-register move. It then attempts to change the + registers used by the instruction to avoid the move instruction. + The code is located in `regmove.c'. + + * Mode switching optimization + + This pass looks for instructions that require the processor to be + in a specific "mode" and minimizes the number of mode changes + required to satisfy all users. What these modes are, and what + they apply to are completely target-specific. The code for this + pass is located in `mode-switching.c'. + + * Modulo scheduling + + This pass looks at innermost loops and reorders their instructions + by overlapping different iterations. Modulo scheduling is + performed immediately before instruction scheduling. The code for + this pass is located in `modulo-sched.c'. + + * Instruction scheduling + + This pass looks for instructions whose output will not be + available by the time that it is used in subsequent instructions. + Memory loads and floating point instructions often have this + behavior on RISC machines. It re-orders instructions within a + basic block to try to separate the definition and use of items + that otherwise would cause pipeline stalls. This pass is + performed twice, before and after register allocation. The code + for this pass is located in `haifa-sched.c', `sched-deps.c', + `sched-ebb.c', `sched-rgn.c' and `sched-vis.c'. + + * Register allocation + + These passes make sure that all occurrences of pseudo registers are + eliminated, either by allocating them to a hard register, replacing + them by an equivalent expression (e.g. a constant) or by placing + them on the stack. This is done in several subpasses: + + * Register move optimizations. This pass makes some simple RTL + code transformations which improve the subsequent register + allocation. The source file is `regmove.c'. + + * The integrated register allocator (IRA). It is called + integrated because coalescing, register live range splitting, + and hard register preferencing are done on-the-fly during + coloring. It also has better integration with the reload + pass. Pseudo-registers spilled by the allocator or the + reload have still a chance to get hard-registers if the + reload evicts some pseudo-registers from hard-registers. The + allocator helps to choose better pseudos for spilling based + on their live ranges and to coalesce stack slots allocated + for the spilled pseudo-registers. IRA is a regional register + allocator which is transformed into Chaitin-Briggs allocator + if there is one region. By default, IRA chooses regions using + register pressure but the user can force it to use one region + or regions corresponding to all loops. + + Source files of the allocator are `ira.c', `ira-build.c', + `ira-costs.c', `ira-conflicts.c', `ira-color.c', + `ira-emit.c', `ira-lives', plus header files `ira.h' and + `ira-int.h' used for the communication between the allocator + and the rest of the compiler and between the IRA files. + + * Reloading. This pass renumbers pseudo registers with the + hardware registers numbers they were allocated. Pseudo + registers that did not get hard registers are replaced with + stack slots. Then it finds instructions that are invalid + because a value has failed to end up in a register, or has + ended up in a register of the wrong kind. It fixes up these + instructions by reloading the problematical values + temporarily into registers. Additional instructions are + generated to do the copying. + + The reload pass also optionally eliminates the frame pointer + and inserts instructions to save and restore call-clobbered + registers around calls. + + Source files are `reload.c' and `reload1.c', plus the header + `reload.h' used for communication between them. + + * Basic block reordering + + This pass implements profile guided code positioning. If profile + information is not available, various types of static analysis are + performed to make the predictions normally coming from the profile + feedback (IE execution frequency, branch probability, etc). It is + implemented in the file `bb-reorder.c', and the various prediction + routines are in `predict.c'. + + * Variable tracking + + This pass computes where the variables are stored at each position + in code and generates notes describing the variable locations to + RTL code. The location lists are then generated according to these + notes to debug information if the debugging information format + supports location lists. The code is located in `var-tracking.c'. + + * Delayed branch scheduling + + This optional pass attempts to find instructions that can go into + the delay slots of other instructions, usually jumps and calls. + The code for this pass is located in `reorg.c'. + + * Branch shortening + + On many RISC machines, branch instructions have a limited range. + Thus, longer sequences of instructions must be used for long + branches. In this pass, the compiler figures out what how far + each instruction will be from each other instruction, and + therefore whether the usual instructions, or the longer sequences, + must be used for each branch. The code for this pass is located + in `final.c'. + + * Register-to-stack conversion + + Conversion from usage of some hard registers to usage of a register + stack may be done at this point. Currently, this is supported only + for the floating-point registers of the Intel 80387 coprocessor. + The code for this pass is located in `reg-stack.c'. + + * Final + + This pass outputs the assembler code for the function. The source + files are `final.c' plus `insn-output.c'; the latter is generated + automatically from the machine description by the tool `genoutput'. + The header file `conditions.h' is used for communication between + these files. If mudflap is enabled, the queue of deferred + declarations and any addressed constants (e.g., string literals) + is processed by `mudflap_finish_file' into a synthetic constructor + function containing calls into the mudflap runtime. + + * Debugging information output + + This is run after final because it must output the stack slot + offsets for pseudo registers that did not get hard registers. + Source files are `dbxout.c' for DBX symbol table format, + `sdbout.c' for SDB symbol table format, `dwarfout.c' for DWARF + symbol table format, files `dwarf2out.c' and `dwarf2asm.c' for + DWARF2 symbol table format, and `vmsdbgout.c' for VMS debug symbol + table format. + + + +File: gccint.info, Node: RTL, Next: Control Flow, Prev: Tree SSA, Up: Top + +10 RTL Representation +********************* + +The last part of the compiler work is done on a low-level intermediate +representation called Register Transfer Language. In this language, the +instructions to be output are described, pretty much one by one, in an +algebraic form that describes what the instruction does. + + RTL is inspired by Lisp lists. It has both an internal form, made up +of structures that point at other structures, and a textual form that +is used in the machine description and in printed debugging dumps. The +textual form uses nested parentheses to indicate the pointers in the +internal form. + +* Menu: + +* RTL Objects:: Expressions vs vectors vs strings vs integers. +* RTL Classes:: Categories of RTL expression objects, and their structure. +* Accessors:: Macros to access expression operands or vector elts. +* Special Accessors:: Macros to access specific annotations on RTL. +* Flags:: Other flags in an RTL expression. +* Machine Modes:: Describing the size and format of a datum. +* Constants:: Expressions with constant values. +* Regs and Memory:: Expressions representing register contents or memory. +* Arithmetic:: Expressions representing arithmetic on other expressions. +* Comparisons:: Expressions representing comparison of expressions. +* Bit-Fields:: Expressions representing bit-fields in memory or reg. +* Vector Operations:: Expressions involving vector datatypes. +* Conversions:: Extending, truncating, floating or fixing. +* RTL Declarations:: Declaring volatility, constancy, etc. +* Side Effects:: Expressions for storing in registers, etc. +* Incdec:: Embedded side-effects for autoincrement addressing. +* Assembler:: Representing `asm' with operands. +* Debug Information:: Expressions representing debugging information. +* Insns:: Expression types for entire insns. +* Calls:: RTL representation of function call insns. +* Sharing:: Some expressions are unique; others *must* be copied. +* Reading RTL:: Reading textual RTL from a file. + + +File: gccint.info, Node: RTL Objects, Next: RTL Classes, Up: RTL + +10.1 RTL Object Types +===================== + +RTL uses five kinds of objects: expressions, integers, wide integers, +strings and vectors. Expressions are the most important ones. An RTL +expression ("RTX", for short) is a C structure, but it is usually +referred to with a pointer; a type that is given the typedef name `rtx'. + + An integer is simply an `int'; their written form uses decimal digits. +A wide integer is an integral object whose type is `HOST_WIDE_INT'; +their written form uses decimal digits. + + A string is a sequence of characters. In core it is represented as a +`char *' in usual C fashion, and it is written in C syntax as well. +However, strings in RTL may never be null. If you write an empty +string in a machine description, it is represented in core as a null +pointer rather than as a pointer to a null character. In certain +contexts, these null pointers instead of strings are valid. Within RTL +code, strings are most commonly found inside `symbol_ref' expressions, +but they appear in other contexts in the RTL expressions that make up +machine descriptions. + + In a machine description, strings are normally written with double +quotes, as you would in C. However, strings in machine descriptions may +extend over many lines, which is invalid C, and adjacent string +constants are not concatenated as they are in C. Any string constant +may be surrounded with a single set of parentheses. Sometimes this +makes the machine description easier to read. + + There is also a special syntax for strings, which can be useful when C +code is embedded in a machine description. Wherever a string can +appear, it is also valid to write a C-style brace block. The entire +brace block, including the outermost pair of braces, is considered to be +the string constant. Double quote characters inside the braces are not +special. Therefore, if you write string constants in the C code, you +need not escape each quote character with a backslash. + + A vector contains an arbitrary number of pointers to expressions. The +number of elements in the vector is explicitly present in the vector. +The written form of a vector consists of square brackets (`[...]') +surrounding the elements, in sequence and with whitespace separating +them. Vectors of length zero are not created; null pointers are used +instead. + + Expressions are classified by "expression codes" (also called RTX +codes). The expression code is a name defined in `rtl.def', which is +also (in uppercase) a C enumeration constant. The possible expression +codes and their meanings are machine-independent. The code of an RTX +can be extracted with the macro `GET_CODE (X)' and altered with +`PUT_CODE (X, NEWCODE)'. + + The expression code determines how many operands the expression +contains, and what kinds of objects they are. In RTL, unlike Lisp, you +cannot tell by looking at an operand what kind of object it is. +Instead, you must know from its context--from the expression code of +the containing expression. For example, in an expression of code +`subreg', the first operand is to be regarded as an expression and the +second operand as an integer. In an expression of code `plus', there +are two operands, both of which are to be regarded as expressions. In +a `symbol_ref' expression, there is one operand, which is to be +regarded as a string. + + Expressions are written as parentheses containing the name of the +expression type, its flags and machine mode if any, and then the +operands of the expression (separated by spaces). + + Expression code names in the `md' file are written in lowercase, but +when they appear in C code they are written in uppercase. In this +manual, they are shown as follows: `const_int'. + + In a few contexts a null pointer is valid where an expression is +normally wanted. The written form of this is `(nil)'. + + +File: gccint.info, Node: RTL Classes, Next: Accessors, Prev: RTL Objects, Up: RTL + +10.2 RTL Classes and Formats +============================ + +The various expression codes are divided into several "classes", which +are represented by single characters. You can determine the class of +an RTX code with the macro `GET_RTX_CLASS (CODE)'. Currently, +`rtl.def' defines these classes: + +`RTX_OBJ' + An RTX code that represents an actual object, such as a register + (`REG') or a memory location (`MEM', `SYMBOL_REF'). `LO_SUM') is + also included; instead, `SUBREG' and `STRICT_LOW_PART' are not in + this class, but in class `x'. + +`RTX_CONST_OBJ' + An RTX code that represents a constant object. `HIGH' is also + included in this class. + +`RTX_COMPARE' + An RTX code for a non-symmetric comparison, such as `GEU' or `LT'. + +`RTX_COMM_COMPARE' + An RTX code for a symmetric (commutative) comparison, such as `EQ' + or `ORDERED'. + +`RTX_UNARY' + An RTX code for a unary arithmetic operation, such as `NEG', + `NOT', or `ABS'. This category also includes value extension + (sign or zero) and conversions between integer and floating point. + +`RTX_COMM_ARITH' + An RTX code for a commutative binary operation, such as `PLUS' or + `AND'. `NE' and `EQ' are comparisons, so they have class `<'. + +`RTX_BIN_ARITH' + An RTX code for a non-commutative binary operation, such as + `MINUS', `DIV', or `ASHIFTRT'. + +`RTX_BITFIELD_OPS' + An RTX code for a bit-field operation. Currently only + `ZERO_EXTRACT' and `SIGN_EXTRACT'. These have three inputs and + are lvalues (so they can be used for insertion as well). *Note + Bit-Fields::. + +`RTX_TERNARY' + An RTX code for other three input operations. Currently only + `IF_THEN_ELSE', `VEC_MERGE', `SIGN_EXTRACT', `ZERO_EXTRACT', and + `FMA'. + +`RTX_INSN' + An RTX code for an entire instruction: `INSN', `JUMP_INSN', and + `CALL_INSN'. *Note Insns::. + +`RTX_MATCH' + An RTX code for something that matches in insns, such as + `MATCH_DUP'. These only occur in machine descriptions. + +`RTX_AUTOINC' + An RTX code for an auto-increment addressing mode, such as + `POST_INC'. + +`RTX_EXTRA' + All other RTX codes. This category includes the remaining codes + used only in machine descriptions (`DEFINE_*', etc.). It also + includes all the codes describing side effects (`SET', `USE', + `CLOBBER', etc.) and the non-insns that may appear on an insn + chain, such as `NOTE', `BARRIER', and `CODE_LABEL'. `SUBREG' is + also part of this class. + + For each expression code, `rtl.def' specifies the number of contained +objects and their kinds using a sequence of characters called the +"format" of the expression code. For example, the format of `subreg' +is `ei'. + + These are the most commonly used format characters: + +`e' + An expression (actually a pointer to an expression). + +`i' + An integer. + +`w' + A wide integer. + +`s' + A string. + +`E' + A vector of expressions. + + A few other format characters are used occasionally: + +`u' + `u' is equivalent to `e' except that it is printed differently in + debugging dumps. It is used for pointers to insns. + +`n' + `n' is equivalent to `i' except that it is printed differently in + debugging dumps. It is used for the line number or code number of + a `note' insn. + +`S' + `S' indicates a string which is optional. In the RTL objects in + core, `S' is equivalent to `s', but when the object is read, from + an `md' file, the string value of this operand may be omitted. An + omitted string is taken to be the null string. + +`V' + `V' indicates a vector which is optional. In the RTL objects in + core, `V' is equivalent to `E', but when the object is read from + an `md' file, the vector value of this operand may be omitted. An + omitted vector is effectively the same as a vector of no elements. + +`B' + `B' indicates a pointer to basic block structure. + +`0' + `0' means a slot whose contents do not fit any normal category. + `0' slots are not printed at all in dumps, and are often used in + special ways by small parts of the compiler. + + There are macros to get the number of operands and the format of an +expression code: + +`GET_RTX_LENGTH (CODE)' + Number of operands of an RTX of code CODE. + +`GET_RTX_FORMAT (CODE)' + The format of an RTX of code CODE, as a C string. + + Some classes of RTX codes always have the same format. For example, it +is safe to assume that all comparison operations have format `ee'. + +`1' + All codes of this class have format `e'. + +`<' +`c' +`2' + All codes of these classes have format `ee'. + +`b' +`3' + All codes of these classes have format `eee'. + +`i' + All codes of this class have formats that begin with `iuueiee'. + *Note Insns::. Note that not all RTL objects linked onto an insn + chain are of class `i'. + +`o' +`m' +`x' + You can make no assumptions about the format of these codes. + + +File: gccint.info, Node: Accessors, Next: Special Accessors, Prev: RTL Classes, Up: RTL + +10.3 Access to Operands +======================= + +Operands of expressions are accessed using the macros `XEXP', `XINT', +`XWINT' and `XSTR'. Each of these macros takes two arguments: an +expression-pointer (RTX) and an operand number (counting from zero). +Thus, + + XEXP (X, 2) + +accesses operand 2 of expression X, as an expression. + + XINT (X, 2) + +accesses the same operand as an integer. `XSTR', used in the same +fashion, would access it as a string. + + Any operand can be accessed as an integer, as an expression or as a +string. You must choose the correct method of access for the kind of +value actually stored in the operand. You would do this based on the +expression code of the containing expression. That is also how you +would know how many operands there are. + + For example, if X is a `subreg' expression, you know that it has two +operands which can be correctly accessed as `XEXP (X, 0)' and `XINT (X, +1)'. If you did `XINT (X, 0)', you would get the address of the +expression operand but cast as an integer; that might occasionally be +useful, but it would be cleaner to write `(int) XEXP (X, 0)'. `XEXP +(X, 1)' would also compile without error, and would return the second, +integer operand cast as an expression pointer, which would probably +result in a crash when accessed. Nothing stops you from writing `XEXP +(X, 28)' either, but this will access memory past the end of the +expression with unpredictable results. + + Access to operands which are vectors is more complicated. You can use +the macro `XVEC' to get the vector-pointer itself, or the macros +`XVECEXP' and `XVECLEN' to access the elements and length of a vector. + +`XVEC (EXP, IDX)' + Access the vector-pointer which is operand number IDX in EXP. + +`XVECLEN (EXP, IDX)' + Access the length (number of elements) in the vector which is in + operand number IDX in EXP. This value is an `int'. + +`XVECEXP (EXP, IDX, ELTNUM)' + Access element number ELTNUM in the vector which is in operand + number IDX in EXP. This value is an RTX. + + It is up to you to make sure that ELTNUM is not negative and is + less than `XVECLEN (EXP, IDX)'. + + All the macros defined in this section expand into lvalues and +therefore can be used to assign the operands, lengths and vector +elements as well as to access them. + + +File: gccint.info, Node: Special Accessors, Next: Flags, Prev: Accessors, Up: RTL + +10.4 Access to Special Operands +=============================== + +Some RTL nodes have special annotations associated with them. + +`MEM' + + `MEM_ALIAS_SET (X)' + If 0, X is not in any alias set, and may alias anything. + Otherwise, X can only alias `MEM's in a conflicting alias + set. This value is set in a language-dependent manner in the + front-end, and should not be altered in the back-end. In + some front-ends, these numbers may correspond in some way to + types, or other language-level entities, but they need not, + and the back-end makes no such assumptions. These set + numbers are tested with `alias_sets_conflict_p'. + + `MEM_EXPR (X)' + If this register is known to hold the value of some user-level + declaration, this is that tree node. It may also be a + `COMPONENT_REF', in which case this is some field reference, + and `TREE_OPERAND (X, 0)' contains the declaration, or + another `COMPONENT_REF', or null if there is no compile-time + object associated with the reference. + + `MEM_OFFSET (X)' + The offset from the start of `MEM_EXPR' as a `CONST_INT' rtx. + + `MEM_SIZE (X)' + The size in bytes of the memory reference as a `CONST_INT' + rtx. This is mostly relevant for `BLKmode' references as + otherwise the size is implied by the mode. + + `MEM_ALIGN (X)' + The known alignment in bits of the memory reference. + + `MEM_ADDR_SPACE (X)' + The address space of the memory reference. This will + commonly be zero for the generic address space. + +`REG' + + `ORIGINAL_REGNO (X)' + This field holds the number the register "originally" had; + for a pseudo register turned into a hard reg this will hold + the old pseudo register number. + + `REG_EXPR (X)' + If this register is known to hold the value of some user-level + declaration, this is that tree node. + + `REG_OFFSET (X)' + If this register is known to hold the value of some user-level + declaration, this is the offset into that logical storage. + +`SYMBOL_REF' + + `SYMBOL_REF_DECL (X)' + If the `symbol_ref' X was created for a `VAR_DECL' or a + `FUNCTION_DECL', that tree is recorded here. If this value is + null, then X was created by back end code generation routines, + and there is no associated front end symbol table entry. + + `SYMBOL_REF_DECL' may also point to a tree of class `'c'', + that is, some sort of constant. In this case, the + `symbol_ref' is an entry in the per-file constant pool; + again, there is no associated front end symbol table entry. + + `SYMBOL_REF_CONSTANT (X)' + If `CONSTANT_POOL_ADDRESS_P (X)' is true, this is the constant + pool entry for X. It is null otherwise. + + `SYMBOL_REF_DATA (X)' + A field of opaque type used to store `SYMBOL_REF_DECL' or + `SYMBOL_REF_CONSTANT'. + + `SYMBOL_REF_FLAGS (X)' + In a `symbol_ref', this is used to communicate various + predicates about the symbol. Some of these are common enough + to be computed by common code, some are specific to the + target. The common bits are: + + `SYMBOL_FLAG_FUNCTION' + Set if the symbol refers to a function. + + `SYMBOL_FLAG_LOCAL' + Set if the symbol is local to this "module". See + `TARGET_BINDS_LOCAL_P'. + + `SYMBOL_FLAG_EXTERNAL' + Set if this symbol is not defined in this translation + unit. Note that this is not the inverse of + `SYMBOL_FLAG_LOCAL'. + + `SYMBOL_FLAG_SMALL' + Set if the symbol is located in the small data section. + See `TARGET_IN_SMALL_DATA_P'. + + `SYMBOL_REF_TLS_MODEL (X)' + This is a multi-bit field accessor that returns the + `tls_model' to be used for a thread-local storage + symbol. It returns zero for non-thread-local symbols. + + `SYMBOL_FLAG_HAS_BLOCK_INFO' + Set if the symbol has `SYMBOL_REF_BLOCK' and + `SYMBOL_REF_BLOCK_OFFSET' fields. + + `SYMBOL_FLAG_ANCHOR' + Set if the symbol is used as a section anchor. "Section + anchors" are symbols that have a known position within + an `object_block' and that can be used to access nearby + members of that block. They are used to implement + `-fsection-anchors'. + + If this flag is set, then `SYMBOL_FLAG_HAS_BLOCK_INFO' + will be too. + + Bits beginning with `SYMBOL_FLAG_MACH_DEP' are available for + the target's use. + +`SYMBOL_REF_BLOCK (X)' + If `SYMBOL_REF_HAS_BLOCK_INFO_P (X)', this is the `object_block' + structure to which the symbol belongs, or `NULL' if it has not + been assigned a block. + +`SYMBOL_REF_BLOCK_OFFSET (X)' + If `SYMBOL_REF_HAS_BLOCK_INFO_P (X)', this is the offset of X from + the first object in `SYMBOL_REF_BLOCK (X)'. The value is negative + if X has not yet been assigned to a block, or it has not been + given an offset within that block. + + +File: gccint.info, Node: Flags, Next: Machine Modes, Prev: Special Accessors, Up: RTL + +10.5 Flags in an RTL Expression +=============================== + +RTL expressions contain several flags (one-bit bit-fields) that are +used in certain types of expression. Most often they are accessed with +the following macros, which expand into lvalues. + +`CONSTANT_POOL_ADDRESS_P (X)' + Nonzero in a `symbol_ref' if it refers to part of the current + function's constant pool. For most targets these addresses are in + a `.rodata' section entirely separate from the function, but for + some targets the addresses are close to the beginning of the + function. In either case GCC assumes these addresses can be + addressed directly, perhaps with the help of base registers. + Stored in the `unchanging' field and printed as `/u'. + +`RTL_CONST_CALL_P (X)' + In a `call_insn' indicates that the insn represents a call to a + const function. Stored in the `unchanging' field and printed as + `/u'. + +`RTL_PURE_CALL_P (X)' + In a `call_insn' indicates that the insn represents a call to a + pure function. Stored in the `return_val' field and printed as + `/i'. + +`RTL_CONST_OR_PURE_CALL_P (X)' + In a `call_insn', true if `RTL_CONST_CALL_P' or `RTL_PURE_CALL_P' + is true. + +`RTL_LOOPING_CONST_OR_PURE_CALL_P (X)' + In a `call_insn' indicates that the insn represents a possibly + infinite looping call to a const or pure function. Stored in the + `call' field and printed as `/c'. Only true if one of + `RTL_CONST_CALL_P' or `RTL_PURE_CALL_P' is true. + +`INSN_ANNULLED_BRANCH_P (X)' + In a `jump_insn', `call_insn', or `insn' indicates that the branch + is an annulling one. See the discussion under `sequence' below. + Stored in the `unchanging' field and printed as `/u'. + +`INSN_DELETED_P (X)' + In an `insn', `call_insn', `jump_insn', `code_label', `barrier', + or `note', nonzero if the insn has been deleted. Stored in the + `volatil' field and printed as `/v'. + +`INSN_FROM_TARGET_P (X)' + In an `insn' or `jump_insn' or `call_insn' in a delay slot of a + branch, indicates that the insn is from the target of the branch. + If the branch insn has `INSN_ANNULLED_BRANCH_P' set, this insn + will only be executed if the branch is taken. For annulled + branches with `INSN_FROM_TARGET_P' clear, the insn will be + executed only if the branch is not taken. When + `INSN_ANNULLED_BRANCH_P' is not set, this insn will always be + executed. Stored in the `in_struct' field and printed as `/s'. + +`LABEL_PRESERVE_P (X)' + In a `code_label' or `note', indicates that the label is + referenced by code or data not visible to the RTL of a given + function. Labels referenced by a non-local goto will have this + bit set. Stored in the `in_struct' field and printed as `/s'. + +`LABEL_REF_NONLOCAL_P (X)' + In `label_ref' and `reg_label' expressions, nonzero if this is a + reference to a non-local label. Stored in the `volatil' field and + printed as `/v'. + +`MEM_IN_STRUCT_P (X)' + In `mem' expressions, nonzero for reference to an entire structure, + union or array, or to a component of one. Zero for references to a + scalar variable or through a pointer to a scalar. If both this + flag and `MEM_SCALAR_P' are clear, then we don't know whether this + `mem' is in a structure or not. Both flags should never be + simultaneously set. Stored in the `in_struct' field and printed + as `/s'. + +`MEM_KEEP_ALIAS_SET_P (X)' + In `mem' expressions, 1 if we should keep the alias set for this + mem unchanged when we access a component. Set to 1, for example, + when we are already in a non-addressable component of an aggregate. + Stored in the `jump' field and printed as `/j'. + +`MEM_SCALAR_P (X)' + In `mem' expressions, nonzero for reference to a scalar known not + to be a member of a structure, union, or array. Zero for such + references and for indirections through pointers, even pointers + pointing to scalar types. If both this flag and `MEM_IN_STRUCT_P' + are clear, then we don't know whether this `mem' is in a structure + or not. Both flags should never be simultaneously set. Stored in + the `return_val' field and printed as `/i'. + +`MEM_VOLATILE_P (X)' + In `mem', `asm_operands', and `asm_input' expressions, nonzero for + volatile memory references. Stored in the `volatil' field and + printed as `/v'. + +`MEM_NOTRAP_P (X)' + In `mem', nonzero for memory references that will not trap. + Stored in the `call' field and printed as `/c'. + +`MEM_POINTER (X)' + Nonzero in a `mem' if the memory reference holds a pointer. + Stored in the `frame_related' field and printed as `/f'. + +`REG_FUNCTION_VALUE_P (X)' + Nonzero in a `reg' if it is the place in which this function's + value is going to be returned. (This happens only in a hard + register.) Stored in the `return_val' field and printed as `/i'. + +`REG_POINTER (X)' + Nonzero in a `reg' if the register holds a pointer. Stored in the + `frame_related' field and printed as `/f'. + +`REG_USERVAR_P (X)' + In a `reg', nonzero if it corresponds to a variable present in the + user's source code. Zero for temporaries generated internally by + the compiler. Stored in the `volatil' field and printed as `/v'. + + The same hard register may be used also for collecting the values + of functions called by this one, but `REG_FUNCTION_VALUE_P' is zero + in this kind of use. + +`RTX_FRAME_RELATED_P (X)' + Nonzero in an `insn', `call_insn', `jump_insn', `barrier', or + `set' which is part of a function prologue and sets the stack + pointer, sets the frame pointer, or saves a register. This flag + should also be set on an instruction that sets up a temporary + register to use in place of the frame pointer. Stored in the + `frame_related' field and printed as `/f'. + + In particular, on RISC targets where there are limits on the sizes + of immediate constants, it is sometimes impossible to reach the + register save area directly from the stack pointer. In that case, + a temporary register is used that is near enough to the register + save area, and the Canonical Frame Address, i.e., DWARF2's logical + frame pointer, register must (temporarily) be changed to be this + temporary register. So, the instruction that sets this temporary + register must be marked as `RTX_FRAME_RELATED_P'. + + If the marked instruction is overly complex (defined in terms of + what `dwarf2out_frame_debug_expr' can handle), you will also have + to create a `REG_FRAME_RELATED_EXPR' note and attach it to the + instruction. This note should contain a simple expression of the + computation performed by this instruction, i.e., one that + `dwarf2out_frame_debug_expr' can handle. + + This flag is required for exception handling support on targets + with RTL prologues. + +`MEM_READONLY_P (X)' + Nonzero in a `mem', if the memory is statically allocated and + read-only. + + Read-only in this context means never modified during the lifetime + of the program, not necessarily in ROM or in write-disabled pages. + A common example of the later is a shared library's global offset + table. This table is initialized by the runtime loader, so the + memory is technically writable, but after control is transfered + from the runtime loader to the application, this memory will never + be subsequently modified. + + Stored in the `unchanging' field and printed as `/u'. + +`SCHED_GROUP_P (X)' + During instruction scheduling, in an `insn', `call_insn' or + `jump_insn', indicates that the previous insn must be scheduled + together with this insn. This is used to ensure that certain + groups of instructions will not be split up by the instruction + scheduling pass, for example, `use' insns before a `call_insn' may + not be separated from the `call_insn'. Stored in the `in_struct' + field and printed as `/s'. + +`SET_IS_RETURN_P (X)' + For a `set', nonzero if it is for a return. Stored in the `jump' + field and printed as `/j'. + +`SIBLING_CALL_P (X)' + For a `call_insn', nonzero if the insn is a sibling call. Stored + in the `jump' field and printed as `/j'. + +`STRING_POOL_ADDRESS_P (X)' + For a `symbol_ref' expression, nonzero if it addresses this + function's string constant pool. Stored in the `frame_related' + field and printed as `/f'. + +`SUBREG_PROMOTED_UNSIGNED_P (X)' + Returns a value greater then zero for a `subreg' that has + `SUBREG_PROMOTED_VAR_P' nonzero if the object being referenced is + kept zero-extended, zero if it is kept sign-extended, and less + then zero if it is extended some other way via the `ptr_extend' + instruction. Stored in the `unchanging' field and `volatil' + field, printed as `/u' and `/v'. This macro may only be used to + get the value it may not be used to change the value. Use + `SUBREG_PROMOTED_UNSIGNED_SET' to change the value. + +`SUBREG_PROMOTED_UNSIGNED_SET (X)' + Set the `unchanging' and `volatil' fields in a `subreg' to reflect + zero, sign, or other extension. If `volatil' is zero, then + `unchanging' as nonzero means zero extension and as zero means + sign extension. If `volatil' is nonzero then some other type of + extension was done via the `ptr_extend' instruction. + +`SUBREG_PROMOTED_VAR_P (X)' + Nonzero in a `subreg' if it was made when accessing an object that + was promoted to a wider mode in accord with the `PROMOTED_MODE' + machine description macro (*note Storage Layout::). In this case, + the mode of the `subreg' is the declared mode of the object and + the mode of `SUBREG_REG' is the mode of the register that holds + the object. Promoted variables are always either sign- or + zero-extended to the wider mode on every assignment. Stored in + the `in_struct' field and printed as `/s'. + +`SYMBOL_REF_USED (X)' + In a `symbol_ref', indicates that X has been used. This is + normally only used to ensure that X is only declared external + once. Stored in the `used' field. + +`SYMBOL_REF_WEAK (X)' + In a `symbol_ref', indicates that X has been declared weak. + Stored in the `return_val' field and printed as `/i'. + +`SYMBOL_REF_FLAG (X)' + In a `symbol_ref', this is used as a flag for machine-specific + purposes. Stored in the `volatil' field and printed as `/v'. + + Most uses of `SYMBOL_REF_FLAG' are historic and may be subsumed by + `SYMBOL_REF_FLAGS'. Certainly use of `SYMBOL_REF_FLAGS' is + mandatory if the target requires more than one bit of storage. + +`PREFETCH_SCHEDULE_BARRIER_P (X)' + In a `prefetch', indicates that the prefetch is a scheduling + barrier. No other INSNs will be moved over it. Stored in the + `volatil' field and printed as `/v'. + + These are the fields to which the above macros refer: + +`call' + In a `mem', 1 means that the memory reference will not trap. + + In a `call', 1 means that this pure or const call may possibly + infinite loop. + + In an RTL dump, this flag is represented as `/c'. + +`frame_related' + In an `insn' or `set' expression, 1 means that it is part of a + function prologue and sets the stack pointer, sets the frame + pointer, saves a register, or sets up a temporary register to use + in place of the frame pointer. + + In `reg' expressions, 1 means that the register holds a pointer. + + In `mem' expressions, 1 means that the memory reference holds a + pointer. + + In `symbol_ref' expressions, 1 means that the reference addresses + this function's string constant pool. + + In an RTL dump, this flag is represented as `/f'. + +`in_struct' + In `mem' expressions, it is 1 if the memory datum referred to is + all or part of a structure or array; 0 if it is (or might be) a + scalar variable. A reference through a C pointer has 0 because + the pointer might point to a scalar variable. This information + allows the compiler to determine something about possible cases of + aliasing. + + In `reg' expressions, it is 1 if the register has its entire life + contained within the test expression of some loop. + + In `subreg' expressions, 1 means that the `subreg' is accessing an + object that has had its mode promoted from a wider mode. + + In `label_ref' expressions, 1 means that the referenced label is + outside the innermost loop containing the insn in which the + `label_ref' was found. + + In `code_label' expressions, it is 1 if the label may never be + deleted. This is used for labels which are the target of + non-local gotos. Such a label that would have been deleted is + replaced with a `note' of type `NOTE_INSN_DELETED_LABEL'. + + In an `insn' during dead-code elimination, 1 means that the insn is + dead code. + + In an `insn' or `jump_insn' during reorg for an insn in the delay + slot of a branch, 1 means that this insn is from the target of the + branch. + + In an `insn' during instruction scheduling, 1 means that this insn + must be scheduled as part of a group together with the previous + insn. + + In an RTL dump, this flag is represented as `/s'. + +`return_val' + In `reg' expressions, 1 means the register contains the value to + be returned by the current function. On machines that pass + parameters in registers, the same register number may be used for + parameters as well, but this flag is not set on such uses. + + In `mem' expressions, 1 means the memory reference is to a scalar + known not to be a member of a structure, union, or array. + + In `symbol_ref' expressions, 1 means the referenced symbol is weak. + + In `call' expressions, 1 means the call is pure. + + In an RTL dump, this flag is represented as `/i'. + +`jump' + In a `mem' expression, 1 means we should keep the alias set for + this mem unchanged when we access a component. + + In a `set', 1 means it is for a return. + + In a `call_insn', 1 means it is a sibling call. + + In an RTL dump, this flag is represented as `/j'. + +`unchanging' + In `reg' and `mem' expressions, 1 means that the value of the + expression never changes. + + In `subreg' expressions, it is 1 if the `subreg' references an + unsigned object whose mode has been promoted to a wider mode. + + In an `insn' or `jump_insn' in the delay slot of a branch + instruction, 1 means an annulling branch should be used. + + In a `symbol_ref' expression, 1 means that this symbol addresses + something in the per-function constant pool. + + In a `call_insn' 1 means that this instruction is a call to a const + function. + + In an RTL dump, this flag is represented as `/u'. + +`used' + This flag is used directly (without an access macro) at the end of + RTL generation for a function, to count the number of times an + expression appears in insns. Expressions that appear more than + once are copied, according to the rules for shared structure + (*note Sharing::). + + For a `reg', it is used directly (without an access macro) by the + leaf register renumbering code to ensure that each register is only + renumbered once. + + In a `symbol_ref', it indicates that an external declaration for + the symbol has already been written. + +`volatil' + In a `mem', `asm_operands', or `asm_input' expression, it is 1 if + the memory reference is volatile. Volatile memory references may + not be deleted, reordered or combined. + + In a `symbol_ref' expression, it is used for machine-specific + purposes. + + In a `reg' expression, it is 1 if the value is a user-level + variable. 0 indicates an internal compiler temporary. + + In an `insn', 1 means the insn has been deleted. + + In `label_ref' and `reg_label' expressions, 1 means a reference to + a non-local label. + + In `prefetch' expressions, 1 means that the containing insn is a + scheduling barrier. + + In an RTL dump, this flag is represented as `/v'. + + +File: gccint.info, Node: Machine Modes, Next: Constants, Prev: Flags, Up: RTL + +10.6 Machine Modes +================== + +A machine mode describes a size of data object and the representation +used for it. In the C code, machine modes are represented by an +enumeration type, `enum machine_mode', defined in `machmode.def'. Each +RTL expression has room for a machine mode and so do certain kinds of +tree expressions (declarations and types, to be precise). + + In debugging dumps and machine descriptions, the machine mode of an RTL +expression is written after the expression code with a colon to separate +them. The letters `mode' which appear at the end of each machine mode +name are omitted. For example, `(reg:SI 38)' is a `reg' expression +with machine mode `SImode'. If the mode is `VOIDmode', it is not +written at all. + + Here is a table of machine modes. The term "byte" below refers to an +object of `BITS_PER_UNIT' bits (*note Storage Layout::). + +`BImode' + "Bit" mode represents a single bit, for predicate registers. + +`QImode' + "Quarter-Integer" mode represents a single byte treated as an + integer. + +`HImode' + "Half-Integer" mode represents a two-byte integer. + +`PSImode' + "Partial Single Integer" mode represents an integer which occupies + four bytes but which doesn't really use all four. On some + machines, this is the right mode to use for pointers. + +`SImode' + "Single Integer" mode represents a four-byte integer. + +`PDImode' + "Partial Double Integer" mode represents an integer which occupies + eight bytes but which doesn't really use all eight. On some + machines, this is the right mode to use for certain pointers. + +`DImode' + "Double Integer" mode represents an eight-byte integer. + +`TImode' + "Tetra Integer" (?) mode represents a sixteen-byte integer. + +`OImode' + "Octa Integer" (?) mode represents a thirty-two-byte integer. + +`QFmode' + "Quarter-Floating" mode represents a quarter-precision (single + byte) floating point number. + +`HFmode' + "Half-Floating" mode represents a half-precision (two byte) + floating point number. + +`TQFmode' + "Three-Quarter-Floating" (?) mode represents a + three-quarter-precision (three byte) floating point number. + +`SFmode' + "Single Floating" mode represents a four byte floating point + number. In the common case, of a processor with IEEE arithmetic + and 8-bit bytes, this is a single-precision IEEE floating point + number; it can also be used for double-precision (on processors + with 16-bit bytes) and single-precision VAX and IBM types. + +`DFmode' + "Double Floating" mode represents an eight byte floating point + number. In the common case, of a processor with IEEE arithmetic + and 8-bit bytes, this is a double-precision IEEE floating point + number. + +`XFmode' + "Extended Floating" mode represents an IEEE extended floating point + number. This mode only has 80 meaningful bits (ten bytes). Some + processors require such numbers to be padded to twelve bytes, + others to sixteen; this mode is used for either. + +`SDmode' + "Single Decimal Floating" mode represents a four byte decimal + floating point number (as distinct from conventional binary + floating point). + +`DDmode' + "Double Decimal Floating" mode represents an eight byte decimal + floating point number. + +`TDmode' + "Tetra Decimal Floating" mode represents a sixteen byte decimal + floating point number all 128 of whose bits are meaningful. + +`TFmode' + "Tetra Floating" mode represents a sixteen byte floating point + number all 128 of whose bits are meaningful. One common use is the + IEEE quad-precision format. + +`QQmode' + "Quarter-Fractional" mode represents a single byte treated as a + signed fractional number. The default format is "s.7". + +`HQmode' + "Half-Fractional" mode represents a two-byte signed fractional + number. The default format is "s.15". + +`SQmode' + "Single Fractional" mode represents a four-byte signed fractional + number. The default format is "s.31". + +`DQmode' + "Double Fractional" mode represents an eight-byte signed + fractional number. The default format is "s.63". + +`TQmode' + "Tetra Fractional" mode represents a sixteen-byte signed + fractional number. The default format is "s.127". + +`UQQmode' + "Unsigned Quarter-Fractional" mode represents a single byte + treated as an unsigned fractional number. The default format is + ".8". + +`UHQmode' + "Unsigned Half-Fractional" mode represents a two-byte unsigned + fractional number. The default format is ".16". + +`USQmode' + "Unsigned Single Fractional" mode represents a four-byte unsigned + fractional number. The default format is ".32". + +`UDQmode' + "Unsigned Double Fractional" mode represents an eight-byte unsigned + fractional number. The default format is ".64". + +`UTQmode' + "Unsigned Tetra Fractional" mode represents a sixteen-byte unsigned + fractional number. The default format is ".128". + +`HAmode' + "Half-Accumulator" mode represents a two-byte signed accumulator. + The default format is "s8.7". + +`SAmode' + "Single Accumulator" mode represents a four-byte signed + accumulator. The default format is "s16.15". + +`DAmode' + "Double Accumulator" mode represents an eight-byte signed + accumulator. The default format is "s32.31". + +`TAmode' + "Tetra Accumulator" mode represents a sixteen-byte signed + accumulator. The default format is "s64.63". + +`UHAmode' + "Unsigned Half-Accumulator" mode represents a two-byte unsigned + accumulator. The default format is "8.8". + +`USAmode' + "Unsigned Single Accumulator" mode represents a four-byte unsigned + accumulator. The default format is "16.16". + +`UDAmode' + "Unsigned Double Accumulator" mode represents an eight-byte + unsigned accumulator. The default format is "32.32". + +`UTAmode' + "Unsigned Tetra Accumulator" mode represents a sixteen-byte + unsigned accumulator. The default format is "64.64". + +`CCmode' + "Condition Code" mode represents the value of a condition code, + which is a machine-specific set of bits used to represent the + result of a comparison operation. Other machine-specific modes + may also be used for the condition code. These modes are not used + on machines that use `cc0' (*note Condition Code::). + +`BLKmode' + "Block" mode represents values that are aggregates to which none of + the other modes apply. In RTL, only memory references can have + this mode, and only if they appear in string-move or vector + instructions. On machines which have no such instructions, + `BLKmode' will not appear in RTL. + +`VOIDmode' + Void mode means the absence of a mode or an unspecified mode. For + example, RTL expressions of code `const_int' have mode `VOIDmode' + because they can be taken to have whatever mode the context + requires. In debugging dumps of RTL, `VOIDmode' is expressed by + the absence of any mode. + +`QCmode, HCmode, SCmode, DCmode, XCmode, TCmode' + These modes stand for a complex number represented as a pair of + floating point values. The floating point values are in `QFmode', + `HFmode', `SFmode', `DFmode', `XFmode', and `TFmode', respectively. + +`CQImode, CHImode, CSImode, CDImode, CTImode, COImode' + These modes stand for a complex number represented as a pair of + integer values. The integer values are in `QImode', `HImode', + `SImode', `DImode', `TImode', and `OImode', respectively. + + The machine description defines `Pmode' as a C macro which expands +into the machine mode used for addresses. Normally this is the mode +whose size is `BITS_PER_WORD', `SImode' on 32-bit machines. + + The only modes which a machine description must support are `QImode', +and the modes corresponding to `BITS_PER_WORD', `FLOAT_TYPE_SIZE' and +`DOUBLE_TYPE_SIZE'. The compiler will attempt to use `DImode' for +8-byte structures and unions, but this can be prevented by overriding +the definition of `MAX_FIXED_MODE_SIZE'. Alternatively, you can have +the compiler use `TImode' for 16-byte structures and unions. Likewise, +you can arrange for the C type `short int' to avoid using `HImode'. + + Very few explicit references to machine modes remain in the compiler +and these few references will soon be removed. Instead, the machine +modes are divided into mode classes. These are represented by the +enumeration type `enum mode_class' defined in `machmode.h'. The +possible mode classes are: + +`MODE_INT' + Integer modes. By default these are `BImode', `QImode', `HImode', + `SImode', `DImode', `TImode', and `OImode'. + +`MODE_PARTIAL_INT' + The "partial integer" modes, `PQImode', `PHImode', `PSImode' and + `PDImode'. + +`MODE_FLOAT' + Floating point modes. By default these are `QFmode', `HFmode', + `TQFmode', `SFmode', `DFmode', `XFmode' and `TFmode'. + +`MODE_DECIMAL_FLOAT' + Decimal floating point modes. By default these are `SDmode', + `DDmode' and `TDmode'. + +`MODE_FRACT' + Signed fractional modes. By default these are `QQmode', `HQmode', + `SQmode', `DQmode' and `TQmode'. + +`MODE_UFRACT' + Unsigned fractional modes. By default these are `UQQmode', + `UHQmode', `USQmode', `UDQmode' and `UTQmode'. + +`MODE_ACCUM' + Signed accumulator modes. By default these are `HAmode', + `SAmode', `DAmode' and `TAmode'. + +`MODE_UACCUM' + Unsigned accumulator modes. By default these are `UHAmode', + `USAmode', `UDAmode' and `UTAmode'. + +`MODE_COMPLEX_INT' + Complex integer modes. (These are not currently implemented). + +`MODE_COMPLEX_FLOAT' + Complex floating point modes. By default these are `QCmode', + `HCmode', `SCmode', `DCmode', `XCmode', and `TCmode'. + +`MODE_FUNCTION' + Algol or Pascal function variables including a static chain. + (These are not currently implemented). + +`MODE_CC' + Modes representing condition code values. These are `CCmode' plus + any `CC_MODE' modes listed in the `MACHINE-modes.def'. *Note Jump + Patterns::, also see *note Condition Code::. + +`MODE_RANDOM' + This is a catchall mode class for modes which don't fit into the + above classes. Currently `VOIDmode' and `BLKmode' are in + `MODE_RANDOM'. + + Here are some C macros that relate to machine modes: + +`GET_MODE (X)' + Returns the machine mode of the RTX X. + +`PUT_MODE (X, NEWMODE)' + Alters the machine mode of the RTX X to be NEWMODE. + +`NUM_MACHINE_MODES' + Stands for the number of machine modes available on the target + machine. This is one greater than the largest numeric value of any + machine mode. + +`GET_MODE_NAME (M)' + Returns the name of mode M as a string. + +`GET_MODE_CLASS (M)' + Returns the mode class of mode M. + +`GET_MODE_WIDER_MODE (M)' + Returns the next wider natural mode. For example, the expression + `GET_MODE_WIDER_MODE (QImode)' returns `HImode'. + +`GET_MODE_SIZE (M)' + Returns the size in bytes of a datum of mode M. + +`GET_MODE_BITSIZE (M)' + Returns the size in bits of a datum of mode M. + +`GET_MODE_IBIT (M)' + Returns the number of integral bits of a datum of fixed-point mode + M. + +`GET_MODE_FBIT (M)' + Returns the number of fractional bits of a datum of fixed-point + mode M. + +`GET_MODE_MASK (M)' + Returns a bitmask containing 1 for all bits in a word that fit + within mode M. This macro can only be used for modes whose + bitsize is less than or equal to `HOST_BITS_PER_INT'. + +`GET_MODE_ALIGNMENT (M)' + Return the required alignment, in bits, for an object of mode M. + +`GET_MODE_UNIT_SIZE (M)' + Returns the size in bytes of the subunits of a datum of mode M. + This is the same as `GET_MODE_SIZE' except in the case of complex + modes. For them, the unit size is the size of the real or + imaginary part. + +`GET_MODE_NUNITS (M)' + Returns the number of units contained in a mode, i.e., + `GET_MODE_SIZE' divided by `GET_MODE_UNIT_SIZE'. + +`GET_CLASS_NARROWEST_MODE (C)' + Returns the narrowest mode in mode class C. + + The global variables `byte_mode' and `word_mode' contain modes whose +classes are `MODE_INT' and whose bitsizes are either `BITS_PER_UNIT' or +`BITS_PER_WORD', respectively. On 32-bit machines, these are `QImode' +and `SImode', respectively. + + +File: gccint.info, Node: Constants, Next: Regs and Memory, Prev: Machine Modes, Up: RTL + +10.7 Constant Expression Types +============================== + +The simplest RTL expressions are those that represent constant values. + +`(const_int I)' + This type of expression represents the integer value I. I is + customarily accessed with the macro `INTVAL' as in `INTVAL (EXP)', + which is equivalent to `XWINT (EXP, 0)'. + + Constants generated for modes with fewer bits than `HOST_WIDE_INT' + must be sign extended to full width (e.g., with `gen_int_mode'). + + There is only one expression object for the integer value zero; it + is the value of the variable `const0_rtx'. Likewise, the only + expression for integer value one is found in `const1_rtx', the only + expression for integer value two is found in `const2_rtx', and the + only expression for integer value negative one is found in + `constm1_rtx'. Any attempt to create an expression of code + `const_int' and value zero, one, two or negative one will return + `const0_rtx', `const1_rtx', `const2_rtx' or `constm1_rtx' as + appropriate. + + Similarly, there is only one object for the integer whose value is + `STORE_FLAG_VALUE'. It is found in `const_true_rtx'. If + `STORE_FLAG_VALUE' is one, `const_true_rtx' and `const1_rtx' will + point to the same object. If `STORE_FLAG_VALUE' is -1, + `const_true_rtx' and `constm1_rtx' will point to the same object. + +`(const_double:M I0 I1 ...)' + Represents either a floating-point constant of mode M or an + integer constant too large to fit into `HOST_BITS_PER_WIDE_INT' + bits but small enough to fit within twice that number of bits (GCC + does not provide a mechanism to represent even larger constants). + In the latter case, M will be `VOIDmode'. + + If M is `VOIDmode', the bits of the value are stored in I0 and I1. + I0 is customarily accessed with the macro `CONST_DOUBLE_LOW' and + I1 with `CONST_DOUBLE_HIGH'. + + If the constant is floating point (regardless of its precision), + then the number of integers used to store the value depends on the + size of `REAL_VALUE_TYPE' (*note Floating Point::). The integers + represent a floating point number, but not precisely in the target + machine's or host machine's floating point format. To convert + them to the precise bit pattern used by the target machine, use + the macro `REAL_VALUE_TO_TARGET_DOUBLE' and friends (*note Data + Output::). + +`(const_fixed:M ...)' + Represents a fixed-point constant of mode M. The operand is a + data structure of type `struct fixed_value' and is accessed with + the macro `CONST_FIXED_VALUE'. The high part of data is accessed + with `CONST_FIXED_VALUE_HIGH'; the low part is accessed with + `CONST_FIXED_VALUE_LOW'. + +`(const_vector:M [X0 X1 ...])' + Represents a vector constant. The square brackets stand for the + vector containing the constant elements. X0, X1 and so on are the + `const_int', `const_double' or `const_fixed' elements. + + The number of units in a `const_vector' is obtained with the macro + `CONST_VECTOR_NUNITS' as in `CONST_VECTOR_NUNITS (V)'. + + Individual elements in a vector constant are accessed with the + macro `CONST_VECTOR_ELT' as in `CONST_VECTOR_ELT (V, N)' where V + is the vector constant and N is the element desired. + +`(const_string STR)' + Represents a constant string with value STR. Currently this is + used only for insn attributes (*note Insn Attributes::) since + constant strings in C are placed in memory. + +`(symbol_ref:MODE SYMBOL)' + Represents the value of an assembler label for data. SYMBOL is a + string that describes the name of the assembler label. If it + starts with a `*', the label is the rest of SYMBOL not including + the `*'. Otherwise, the label is SYMBOL, usually prefixed with + `_'. + + The `symbol_ref' contains a mode, which is usually `Pmode'. + Usually that is the only mode for which a symbol is directly valid. + +`(label_ref:MODE LABEL)' + Represents the value of an assembler label for code. It contains + one operand, an expression, which must be a `code_label' or a + `note' of type `NOTE_INSN_DELETED_LABEL' that appears in the + instruction sequence to identify the place where the label should + go. + + The reason for using a distinct expression type for code label + references is so that jump optimization can distinguish them. + + The `label_ref' contains a mode, which is usually `Pmode'. + Usually that is the only mode for which a label is directly valid. + +`(const:M EXP)' + Represents a constant that is the result of an assembly-time + arithmetic computation. The operand, EXP, is an expression that + contains only constants (`const_int', `symbol_ref' and `label_ref' + expressions) combined with `plus' and `minus'. However, not all + combinations are valid, since the assembler cannot do arbitrary + arithmetic on relocatable symbols. + + M should be `Pmode'. + +`(high:M EXP)' + Represents the high-order bits of EXP, usually a `symbol_ref'. + The number of bits is machine-dependent and is normally the number + of bits specified in an instruction that initializes the high + order bits of a register. It is used with `lo_sum' to represent + the typical two-instruction sequence used in RISC machines to + reference a global memory location. + + M should be `Pmode'. + + The macro `CONST0_RTX (MODE)' refers to an expression with value 0 in +mode MODE. If mode MODE is of mode class `MODE_INT', it returns +`const0_rtx'. If mode MODE is of mode class `MODE_FLOAT', it returns a +`CONST_DOUBLE' expression in mode MODE. Otherwise, it returns a +`CONST_VECTOR' expression in mode MODE. Similarly, the macro +`CONST1_RTX (MODE)' refers to an expression with value 1 in mode MODE +and similarly for `CONST2_RTX'. The `CONST1_RTX' and `CONST2_RTX' +macros are undefined for vector modes. + + +File: gccint.info, Node: Regs and Memory, Next: Arithmetic, Prev: Constants, Up: RTL + +10.8 Registers and Memory +========================= + +Here are the RTL expression types for describing access to machine +registers and to main memory. + +`(reg:M N)' + For small values of the integer N (those that are less than + `FIRST_PSEUDO_REGISTER'), this stands for a reference to machine + register number N: a "hard register". For larger values of N, it + stands for a temporary value or "pseudo register". The compiler's + strategy is to generate code assuming an unlimited number of such + pseudo registers, and later convert them into hard registers or + into memory references. + + M is the machine mode of the reference. It is necessary because + machines can generally refer to each register in more than one + mode. For example, a register may contain a full word but there + may be instructions to refer to it as a half word or as a single + byte, as well as instructions to refer to it as a floating point + number of various precisions. + + Even for a register that the machine can access in only one mode, + the mode must always be specified. + + The symbol `FIRST_PSEUDO_REGISTER' is defined by the machine + description, since the number of hard registers on the machine is + an invariant characteristic of the machine. Note, however, that + not all of the machine registers must be general registers. All + the machine registers that can be used for storage of data are + given hard register numbers, even those that can be used only in + certain instructions or can hold only certain types of data. + + A hard register may be accessed in various modes throughout one + function, but each pseudo register is given a natural mode and is + accessed only in that mode. When it is necessary to describe an + access to a pseudo register using a nonnatural mode, a `subreg' + expression is used. + + A `reg' expression with a machine mode that specifies more than + one word of data may actually stand for several consecutive + registers. If in addition the register number specifies a + hardware register, then it actually represents several consecutive + hardware registers starting with the specified one. + + Each pseudo register number used in a function's RTL code is + represented by a unique `reg' expression. + + Some pseudo register numbers, those within the range of + `FIRST_VIRTUAL_REGISTER' to `LAST_VIRTUAL_REGISTER' only appear + during the RTL generation phase and are eliminated before the + optimization phases. These represent locations in the stack frame + that cannot be determined until RTL generation for the function + has been completed. The following virtual register numbers are + defined: + + `VIRTUAL_INCOMING_ARGS_REGNUM' + This points to the first word of the incoming arguments + passed on the stack. Normally these arguments are placed + there by the caller, but the callee may have pushed some + arguments that were previously passed in registers. + + When RTL generation is complete, this virtual register is + replaced by the sum of the register given by + `ARG_POINTER_REGNUM' and the value of `FIRST_PARM_OFFSET'. + + `VIRTUAL_STACK_VARS_REGNUM' + If `FRAME_GROWS_DOWNWARD' is defined to a nonzero value, this + points to immediately above the first variable on the stack. + Otherwise, it points to the first variable on the stack. + + `VIRTUAL_STACK_VARS_REGNUM' is replaced with the sum of the + register given by `FRAME_POINTER_REGNUM' and the value + `STARTING_FRAME_OFFSET'. + + `VIRTUAL_STACK_DYNAMIC_REGNUM' + This points to the location of dynamically allocated memory + on the stack immediately after the stack pointer has been + adjusted by the amount of memory desired. + + This virtual register is replaced by the sum of the register + given by `STACK_POINTER_REGNUM' and the value + `STACK_DYNAMIC_OFFSET'. + + `VIRTUAL_OUTGOING_ARGS_REGNUM' + This points to the location in the stack at which outgoing + arguments should be written when the stack is pre-pushed + (arguments pushed using push insns should always use + `STACK_POINTER_REGNUM'). + + This virtual register is replaced by the sum of the register + given by `STACK_POINTER_REGNUM' and the value + `STACK_POINTER_OFFSET'. + +`(subreg:M1 REG:M2 BYTENUM)' + `subreg' expressions are used to refer to a register in a machine + mode other than its natural one, or to refer to one register of a + multi-part `reg' that actually refers to several registers. + + Each pseudo register has a natural mode. If it is necessary to + operate on it in a different mode, the register must be enclosed + in a `subreg'. + + There are currently three supported types for the first operand of + a `subreg': + * pseudo registers This is the most common case. Most + `subreg's have pseudo `reg's as their first operand. + + * mem `subreg's of `mem' were common in earlier versions of GCC + and are still supported. During the reload pass these are + replaced by plain `mem's. On machines that do not do + instruction scheduling, use of `subreg's of `mem' are still + used, but this is no longer recommended. Such `subreg's are + considered to be `register_operand's rather than + `memory_operand's before and during reload. Because of this, + the scheduling passes cannot properly schedule instructions + with `subreg's of `mem', so for machines that do scheduling, + `subreg's of `mem' should never be used. To support this, + the combine and recog passes have explicit code to inhibit + the creation of `subreg's of `mem' when `INSN_SCHEDULING' is + defined. + + The use of `subreg's of `mem' after the reload pass is an area + that is not well understood and should be avoided. There is + still some code in the compiler to support this, but this + code has possibly rotted. This use of `subreg's is + discouraged and will most likely not be supported in the + future. + + * hard registers It is seldom necessary to wrap hard registers + in `subreg's; such registers would normally reduce to a + single `reg' rtx. This use of `subreg's is discouraged and + may not be supported in the future. + + + `subreg's of `subreg's are not supported. Using + `simplify_gen_subreg' is the recommended way to avoid this problem. + + `subreg's come in two distinct flavors, each having its own usage + and rules: + + Paradoxical subregs + When M1 is strictly wider than M2, the `subreg' expression is + called "paradoxical". The canonical test for this class of + `subreg' is: + + GET_MODE_SIZE (M1) > GET_MODE_SIZE (M2) + + Paradoxical `subreg's can be used as both lvalues and rvalues. + When used as an lvalue, the low-order bits of the source value + are stored in REG and the high-order bits are discarded. + When used as an rvalue, the low-order bits of the `subreg' are + taken from REG while the high-order bits may or may not be + defined. + + The high-order bits of rvalues are in the following + circumstances: + + * `subreg's of `mem' When M2 is smaller than a word, the + macro `LOAD_EXTEND_OP', can control how the high-order + bits are defined. + + * `subreg' of `reg's The upper bits are defined when + `SUBREG_PROMOTED_VAR_P' is true. + `SUBREG_PROMOTED_UNSIGNED_P' describes what the upper + bits hold. Such subregs usually represent local + variables, register variables and parameter pseudo + variables that have been promoted to a wider mode. + + + BYTENUM is always zero for a paradoxical `subreg', even on + big-endian targets. + + For example, the paradoxical `subreg': + + (set (subreg:SI (reg:HI X) 0) Y) + + stores the lower 2 bytes of Y in X and discards the upper 2 + bytes. A subsequent: + + (set Z (subreg:SI (reg:HI X) 0)) + + would set the lower two bytes of Z to Y and set the upper two + bytes to an unknown value assuming `SUBREG_PROMOTED_VAR_P' is + false. + + Normal subregs + When M1 is at least as narrow as M2 the `subreg' expression + is called "normal". + + Normal `subreg's restrict consideration to certain bits of + REG. There are two cases. If M1 is smaller than a word, the + `subreg' refers to the least-significant part (or "lowpart") + of one word of REG. If M1 is word-sized or greater, the + `subreg' refers to one or more complete words. + + When used as an lvalue, `subreg' is a word-based accessor. + Storing to a `subreg' modifies all the words of REG that + overlap the `subreg', but it leaves the other words of REG + alone. + + When storing to a normal `subreg' that is smaller than a word, + the other bits of the referenced word are usually left in an + undefined state. This laxity makes it easier to generate + efficient code for such instructions. To represent an + instruction that preserves all the bits outside of those in + the `subreg', use `strict_low_part' or `zero_extract' around + the `subreg'. + + BYTENUM must identify the offset of the first byte of the + `subreg' from the start of REG, assuming that REG is laid out + in memory order. The memory order of bytes is defined by two + target macros, `WORDS_BIG_ENDIAN' and `BYTES_BIG_ENDIAN': + + * `WORDS_BIG_ENDIAN', if set to 1, says that byte number + zero is part of the most significant word; otherwise, it + is part of the least significant word. + + * `BYTES_BIG_ENDIAN', if set to 1, says that byte number + zero is the most significant byte within a word; + otherwise, it is the least significant byte within a + word. + + On a few targets, `FLOAT_WORDS_BIG_ENDIAN' disagrees with + `WORDS_BIG_ENDIAN'. However, most parts of the compiler treat + floating point values as if they had the same endianness as + integer values. This works because they handle them solely + as a collection of integer values, with no particular + numerical value. Only real.c and the runtime libraries care + about `FLOAT_WORDS_BIG_ENDIAN'. + + Thus, + + (subreg:HI (reg:SI X) 2) + + on a `BYTES_BIG_ENDIAN', `UNITS_PER_WORD == 4' target is the + same as + + (subreg:HI (reg:SI X) 0) + + on a little-endian, `UNITS_PER_WORD == 4' target. Both + `subreg's access the lower two bytes of register X. + + + A `MODE_PARTIAL_INT' mode behaves as if it were as wide as the + corresponding `MODE_INT' mode, except that it has an unknown + number of undefined bits. For example: + + (subreg:PSI (reg:SI 0) 0) + + accesses the whole of `(reg:SI 0)', but the exact relationship + between the `PSImode' value and the `SImode' value is not defined. + If we assume `UNITS_PER_WORD <= 4', then the following two + `subreg's: + + (subreg:PSI (reg:DI 0) 0) + (subreg:PSI (reg:DI 0) 4) + + represent independent 4-byte accesses to the two halves of + `(reg:DI 0)'. Both `subreg's have an unknown number of undefined + bits. + + If `UNITS_PER_WORD <= 2' then these two `subreg's: + + (subreg:HI (reg:PSI 0) 0) + (subreg:HI (reg:PSI 0) 2) + + represent independent 2-byte accesses that together span the whole + of `(reg:PSI 0)'. Storing to the first `subreg' does not affect + the value of the second, and vice versa. `(reg:PSI 0)' has an + unknown number of undefined bits, so the assignment: + + (set (subreg:HI (reg:PSI 0) 0) (reg:HI 4)) + + does not guarantee that `(subreg:HI (reg:PSI 0) 0)' has the value + `(reg:HI 4)'. + + The rules above apply to both pseudo REGs and hard REGs. If the + semantics are not correct for particular combinations of M1, M2 + and hard REG, the target-specific code must ensure that those + combinations are never used. For example: + + CANNOT_CHANGE_MODE_CLASS (M2, M1, CLASS) + + must be true for every class CLASS that includes REG. + + The first operand of a `subreg' expression is customarily accessed + with the `SUBREG_REG' macro and the second operand is customarily + accessed with the `SUBREG_BYTE' macro. + + It has been several years since a platform in which + `BYTES_BIG_ENDIAN' not equal to `WORDS_BIG_ENDIAN' has been + tested. Anyone wishing to support such a platform in the future + may be confronted with code rot. + +`(scratch:M)' + This represents a scratch register that will be required for the + execution of a single instruction and not used subsequently. It is + converted into a `reg' by either the local register allocator or + the reload pass. + + `scratch' is usually present inside a `clobber' operation (*note + Side Effects::). + +`(cc0)' + This refers to the machine's condition code register. It has no + operands and may not have a machine mode. There are two ways to + use it: + + * To stand for a complete set of condition code flags. This is + best on most machines, where each comparison sets the entire + series of flags. + + With this technique, `(cc0)' may be validly used in only two + contexts: as the destination of an assignment (in test and + compare instructions) and in comparison operators comparing + against zero (`const_int' with value zero; that is to say, + `const0_rtx'). + + * To stand for a single flag that is the result of a single + condition. This is useful on machines that have only a + single flag bit, and in which comparison instructions must + specify the condition to test. + + With this technique, `(cc0)' may be validly used in only two + contexts: as the destination of an assignment (in test and + compare instructions) where the source is a comparison + operator, and as the first operand of `if_then_else' (in a + conditional branch). + + There is only one expression object of code `cc0'; it is the value + of the variable `cc0_rtx'. Any attempt to create an expression of + code `cc0' will return `cc0_rtx'. + + Instructions can set the condition code implicitly. On many + machines, nearly all instructions set the condition code based on + the value that they compute or store. It is not necessary to + record these actions explicitly in the RTL because the machine + description includes a prescription for recognizing the + instructions that do so (by means of the macro + `NOTICE_UPDATE_CC'). *Note Condition Code::. Only instructions + whose sole purpose is to set the condition code, and instructions + that use the condition code, need mention `(cc0)'. + + On some machines, the condition code register is given a register + number and a `reg' is used instead of `(cc0)'. This is usually the + preferable approach if only a small subset of instructions modify + the condition code. Other machines store condition codes in + general registers; in such cases a pseudo register should be used. + + Some machines, such as the SPARC and RS/6000, have two sets of + arithmetic instructions, one that sets and one that does not set + the condition code. This is best handled by normally generating + the instruction that does not set the condition code, and making a + pattern that both performs the arithmetic and sets the condition + code register (which would not be `(cc0)' in this case). For + examples, search for `addcc' and `andcc' in `sparc.md'. + +`(pc)' + This represents the machine's program counter. It has no operands + and may not have a machine mode. `(pc)' may be validly used only + in certain specific contexts in jump instructions. + + There is only one expression object of code `pc'; it is the value + of the variable `pc_rtx'. Any attempt to create an expression of + code `pc' will return `pc_rtx'. + + All instructions that do not jump alter the program counter + implicitly by incrementing it, but there is no need to mention + this in the RTL. + +`(mem:M ADDR ALIAS)' + This RTX represents a reference to main memory at an address + represented by the expression ADDR. M specifies how large a unit + of memory is accessed. ALIAS specifies an alias set for the + reference. In general two items are in different alias sets if + they cannot reference the same memory address. + + The construct `(mem:BLK (scratch))' is considered to alias all + other memories. Thus it may be used as a memory barrier in + epilogue stack deallocation patterns. + +`(concatM RTX RTX)' + This RTX represents the concatenation of two other RTXs. This is + used for complex values. It should only appear in the RTL + attached to declarations and during RTL generation. It should not + appear in the ordinary insn chain. + +`(concatnM [RTX ...])' + This RTX represents the concatenation of all the RTX to make a + single value. Like `concat', this should only appear in + declarations, and not in the insn chain. + + +File: gccint.info, Node: Arithmetic, Next: Comparisons, Prev: Regs and Memory, Up: RTL + +10.9 RTL Expressions for Arithmetic +=================================== + +Unless otherwise specified, all the operands of arithmetic expressions +must be valid for mode M. An operand is valid for mode M if it has +mode M, or if it is a `const_int' or `const_double' and M is a mode of +class `MODE_INT'. + + For commutative binary operations, constants should be placed in the +second operand. + +`(plus:M X Y)' +`(ss_plus:M X Y)' +`(us_plus:M X Y)' + These three expressions all represent the sum of the values + represented by X and Y carried out in machine mode M. They differ + in their behavior on overflow of integer modes. `plus' wraps + round modulo the width of M; `ss_plus' saturates at the maximum + signed value representable in M; `us_plus' saturates at the + maximum unsigned value. + +`(lo_sum:M X Y)' + This expression represents the sum of X and the low-order bits of + Y. It is used with `high' (*note Constants::) to represent the + typical two-instruction sequence used in RISC machines to + reference a global memory location. + + The number of low order bits is machine-dependent but is normally + the number of bits in a `Pmode' item minus the number of bits set + by `high'. + + M should be `Pmode'. + +`(minus:M X Y)' +`(ss_minus:M X Y)' +`(us_minus:M X Y)' + These three expressions represent the result of subtracting Y from + X, carried out in mode M. Behavior on overflow is the same as for + the three variants of `plus' (see above). + +`(compare:M X Y)' + Represents the result of subtracting Y from X for purposes of + comparison. The result is computed without overflow, as if with + infinite precision. + + Of course, machines can't really subtract with infinite precision. + However, they can pretend to do so when only the sign of the + result will be used, which is the case when the result is stored + in the condition code. And that is the _only_ way this kind of + expression may validly be used: as a value to be stored in the + condition codes, either `(cc0)' or a register. *Note + Comparisons::. + + The mode M is not related to the modes of X and Y, but instead is + the mode of the condition code value. If `(cc0)' is used, it is + `VOIDmode'. Otherwise it is some mode in class `MODE_CC', often + `CCmode'. *Note Condition Code::. If M is `VOIDmode' or + `CCmode', the operation returns sufficient information (in an + unspecified format) so that any comparison operator can be applied + to the result of the `COMPARE' operation. For other modes in + class `MODE_CC', the operation only returns a subset of this + information. + + Normally, X and Y must have the same mode. Otherwise, `compare' + is valid only if the mode of X is in class `MODE_INT' and Y is a + `const_int' or `const_double' with mode `VOIDmode'. The mode of X + determines what mode the comparison is to be done in; thus it must + not be `VOIDmode'. + + If one of the operands is a constant, it should be placed in the + second operand and the comparison code adjusted as appropriate. + + A `compare' specifying two `VOIDmode' constants is not valid since + there is no way to know in what mode the comparison is to be + performed; the comparison must either be folded during the + compilation or the first operand must be loaded into a register + while its mode is still known. + +`(neg:M X)' +`(ss_neg:M X)' +`(us_neg:M X)' + These two expressions represent the negation (subtraction from + zero) of the value represented by X, carried out in mode M. They + differ in the behavior on overflow of integer modes. In the case + of `neg', the negation of the operand may be a number not + representable in mode M, in which case it is truncated to M. + `ss_neg' and `us_neg' ensure that an out-of-bounds result + saturates to the maximum or minimum signed or unsigned value. + +`(mult:M X Y)' +`(ss_mult:M X Y)' +`(us_mult:M X Y)' + Represents the signed product of the values represented by X and Y + carried out in machine mode M. `ss_mult' and `us_mult' ensure + that an out-of-bounds result saturates to the maximum or minimum + signed or unsigned value. + + Some machines support a multiplication that generates a product + wider than the operands. Write the pattern for this as + + (mult:M (sign_extend:M X) (sign_extend:M Y)) + + where M is wider than the modes of X and Y, which need not be the + same. + + For unsigned widening multiplication, use the same idiom, but with + `zero_extend' instead of `sign_extend'. + +`(fma:M X Y Z)' + Represents the `fma', `fmaf', and `fmal' builtin functions that do + a combined multiply of X and Y and then adding toZ without doing + an intermediate rounding step. + +`(div:M X Y)' +`(ss_div:M X Y)' + Represents the quotient in signed division of X by Y, carried out + in machine mode M. If M is a floating point mode, it represents + the exact quotient; otherwise, the integerized quotient. `ss_div' + ensures that an out-of-bounds result saturates to the maximum or + minimum signed value. + + Some machines have division instructions in which the operands and + quotient widths are not all the same; you should represent such + instructions using `truncate' and `sign_extend' as in, + + (truncate:M1 (div:M2 X (sign_extend:M2 Y))) + +`(udiv:M X Y)' +`(us_div:M X Y)' + Like `div' but represents unsigned division. `us_div' ensures + that an out-of-bounds result saturates to the maximum or minimum + unsigned value. + +`(mod:M X Y)' +`(umod:M X Y)' + Like `div' and `udiv' but represent the remainder instead of the + quotient. + +`(smin:M X Y)' +`(smax:M X Y)' + Represents the smaller (for `smin') or larger (for `smax') of X + and Y, interpreted as signed values in mode M. When used with + floating point, if both operands are zeros, or if either operand + is `NaN', then it is unspecified which of the two operands is + returned as the result. + +`(umin:M X Y)' +`(umax:M X Y)' + Like `smin' and `smax', but the values are interpreted as unsigned + integers. + +`(not:M X)' + Represents the bitwise complement of the value represented by X, + carried out in mode M, which must be a fixed-point machine mode. + +`(and:M X Y)' + Represents the bitwise logical-and of the values represented by X + and Y, carried out in machine mode M, which must be a fixed-point + machine mode. + +`(ior:M X Y)' + Represents the bitwise inclusive-or of the values represented by X + and Y, carried out in machine mode M, which must be a fixed-point + mode. + +`(xor:M X Y)' + Represents the bitwise exclusive-or of the values represented by X + and Y, carried out in machine mode M, which must be a fixed-point + mode. + +`(ashift:M X C)' +`(ss_ashift:M X C)' +`(us_ashift:M X C)' + These three expressions represent the result of arithmetically + shifting X left by C places. They differ in their behavior on + overflow of integer modes. An `ashift' operation is a plain shift + with no special behavior in case of a change in the sign bit; + `ss_ashift' and `us_ashift' saturates to the minimum or maximum + representable value if any of the bits shifted out differs from + the final sign bit. + + X have mode M, a fixed-point machine mode. C be a fixed-point + mode or be a constant with mode `VOIDmode'; which mode is + determined by the mode called for in the machine description entry + for the left-shift instruction. For example, on the VAX, the mode + of C is `QImode' regardless of M. + +`(lshiftrt:M X C)' +`(ashiftrt:M X C)' + Like `ashift' but for right shift. Unlike the case for left shift, + these two operations are distinct. + +`(rotate:M X C)' +`(rotatert:M X C)' + Similar but represent left and right rotate. If C is a constant, + use `rotate'. + +`(abs:M X)' + +`(ss_abs:M X)' + Represents the absolute value of X, computed in mode M. `ss_abs' + ensures that an out-of-bounds result saturates to the maximum + signed value. + +`(sqrt:M X)' + Represents the square root of X, computed in mode M. Most often M + will be a floating point mode. + +`(ffs:M X)' + Represents one plus the index of the least significant 1-bit in X, + represented as an integer of mode M. (The value is zero if X is + zero.) The mode of X need not be M; depending on the target + machine, various mode combinations may be valid. + +`(clz:M X)' + Represents the number of leading 0-bits in X, represented as an + integer of mode M, starting at the most significant bit position. + If X is zero, the value is determined by + `CLZ_DEFINED_VALUE_AT_ZERO' (*note Misc::). Note that this is one + of the few expressions that is not invariant under widening. The + mode of X will usually be an integer mode. + +`(ctz:M X)' + Represents the number of trailing 0-bits in X, represented as an + integer of mode M, starting at the least significant bit position. + If X is zero, the value is determined by + `CTZ_DEFINED_VALUE_AT_ZERO' (*note Misc::). Except for this case, + `ctz(x)' is equivalent to `ffs(X) - 1'. The mode of X will + usually be an integer mode. + +`(popcount:M X)' + Represents the number of 1-bits in X, represented as an integer of + mode M. The mode of X will usually be an integer mode. + +`(parity:M X)' + Represents the number of 1-bits modulo 2 in X, represented as an + integer of mode M. The mode of X will usually be an integer mode. + +`(bswap:M X)' + Represents the value X with the order of bytes reversed, carried + out in mode M, which must be a fixed-point machine mode. + + +File: gccint.info, Node: Comparisons, Next: Bit-Fields, Prev: Arithmetic, Up: RTL + +10.10 Comparison Operations +=========================== + +Comparison operators test a relation on two operands and are considered +to represent a machine-dependent nonzero value described by, but not +necessarily equal to, `STORE_FLAG_VALUE' (*note Misc::) if the relation +holds, or zero if it does not, for comparison operators whose results +have a `MODE_INT' mode, `FLOAT_STORE_FLAG_VALUE' (*note Misc::) if the +relation holds, or zero if it does not, for comparison operators that +return floating-point values, and a vector of either +`VECTOR_STORE_FLAG_VALUE' (*note Misc::) if the relation holds, or of +zeros if it does not, for comparison operators that return vector +results. The mode of the comparison operation is independent of the +mode of the data being compared. If the comparison operation is being +tested (e.g., the first operand of an `if_then_else'), the mode must be +`VOIDmode'. + + There are two ways that comparison operations may be used. The +comparison operators may be used to compare the condition codes `(cc0)' +against zero, as in `(eq (cc0) (const_int 0))'. Such a construct +actually refers to the result of the preceding instruction in which the +condition codes were set. The instruction setting the condition code +must be adjacent to the instruction using the condition code; only +`note' insns may separate them. + + Alternatively, a comparison operation may directly compare two data +objects. The mode of the comparison is determined by the operands; they +must both be valid for a common machine mode. A comparison with both +operands constant would be invalid as the machine mode could not be +deduced from it, but such a comparison should never exist in RTL due to +constant folding. + + In the example above, if `(cc0)' were last set to `(compare X Y)', the +comparison operation is identical to `(eq X Y)'. Usually only one style +of comparisons is supported on a particular machine, but the combine +pass will try to merge the operations to produce the `eq' shown in case +it exists in the context of the particular insn involved. + + Inequality comparisons come in two flavors, signed and unsigned. Thus, +there are distinct expression codes `gt' and `gtu' for signed and +unsigned greater-than. These can produce different results for the same +pair of integer values: for example, 1 is signed greater-than -1 but not +unsigned greater-than, because -1 when regarded as unsigned is actually +`0xffffffff' which is greater than 1. + + The signed comparisons are also used for floating point values. +Floating point comparisons are distinguished by the machine modes of +the operands. + +`(eq:M X Y)' + `STORE_FLAG_VALUE' if the values represented by X and Y are equal, + otherwise 0. + +`(ne:M X Y)' + `STORE_FLAG_VALUE' if the values represented by X and Y are not + equal, otherwise 0. + +`(gt:M X Y)' + `STORE_FLAG_VALUE' if the X is greater than Y. If they are + fixed-point, the comparison is done in a signed sense. + +`(gtu:M X Y)' + Like `gt' but does unsigned comparison, on fixed-point numbers + only. + +`(lt:M X Y)' +`(ltu:M X Y)' + Like `gt' and `gtu' but test for "less than". + +`(ge:M X Y)' +`(geu:M X Y)' + Like `gt' and `gtu' but test for "greater than or equal". + +`(le:M X Y)' +`(leu:M X Y)' + Like `gt' and `gtu' but test for "less than or equal". + +`(if_then_else COND THEN ELSE)' + This is not a comparison operation but is listed here because it is + always used in conjunction with a comparison operation. To be + precise, COND is a comparison expression. This expression + represents a choice, according to COND, between the value + represented by THEN and the one represented by ELSE. + + On most machines, `if_then_else' expressions are valid only to + express conditional jumps. + +`(cond [TEST1 VALUE1 TEST2 VALUE2 ...] DEFAULT)' + Similar to `if_then_else', but more general. Each of TEST1, + TEST2, ... is performed in turn. The result of this expression is + the VALUE corresponding to the first nonzero test, or DEFAULT if + none of the tests are nonzero expressions. + + This is currently not valid for instruction patterns and is + supported only for insn attributes. *Note Insn Attributes::. + + +File: gccint.info, Node: Bit-Fields, Next: Vector Operations, Prev: Comparisons, Up: RTL + +10.11 Bit-Fields +================ + +Special expression codes exist to represent bit-field instructions. + +`(sign_extract:M LOC SIZE POS)' + This represents a reference to a sign-extended bit-field contained + or starting in LOC (a memory or register reference). The bit-field + is SIZE bits wide and starts at bit POS. The compilation option + `BITS_BIG_ENDIAN' says which end of the memory unit POS counts + from. + + If LOC is in memory, its mode must be a single-byte integer mode. + If LOC is in a register, the mode to use is specified by the + operand of the `insv' or `extv' pattern (*note Standard Names::) + and is usually a full-word integer mode, which is the default if + none is specified. + + The mode of POS is machine-specific and is also specified in the + `insv' or `extv' pattern. + + The mode M is the same as the mode that would be used for LOC if + it were a register. + + A `sign_extract' can not appear as an lvalue, or part thereof, in + RTL. + +`(zero_extract:M LOC SIZE POS)' + Like `sign_extract' but refers to an unsigned or zero-extended + bit-field. The same sequence of bits are extracted, but they are + filled to an entire word with zeros instead of by sign-extension. + + Unlike `sign_extract', this type of expressions can be lvalues in + RTL; they may appear on the left side of an assignment, indicating + insertion of a value into the specified bit-field. + + +File: gccint.info, Node: Vector Operations, Next: Conversions, Prev: Bit-Fields, Up: RTL + +10.12 Vector Operations +======================= + +All normal RTL expressions can be used with vector modes; they are +interpreted as operating on each part of the vector independently. +Additionally, there are a few new expressions to describe specific +vector operations. + +`(vec_merge:M VEC1 VEC2 ITEMS)' + This describes a merge operation between two vectors. The result + is a vector of mode M; its elements are selected from either VEC1 + or VEC2. Which elements are selected is described by ITEMS, which + is a bit mask represented by a `const_int'; a zero bit indicates + the corresponding element in the result vector is taken from VEC2 + while a set bit indicates it is taken from VEC1. + +`(vec_select:M VEC1 SELECTION)' + This describes an operation that selects parts of a vector. VEC1 + is the source vector, and SELECTION is a `parallel' that contains a + `const_int' for each of the subparts of the result vector, giving + the number of the source subpart that should be stored into it. + The result mode M is either the submode for a single element of + VEC1 (if only one subpart is selected), or another vector mode + with that element submode (if multiple subparts are selected). + +`(vec_concat:M VEC1 VEC2)' + Describes a vector concat operation. The result is a + concatenation of the vectors VEC1 and VEC2; its length is the sum + of the lengths of the two inputs. + +`(vec_duplicate:M VEC)' + This operation converts a small vector into a larger one by + duplicating the input values. The output vector mode must have + the same submodes as the input vector mode, and the number of + output parts must be an integer multiple of the number of input + parts. + + + +File: gccint.info, Node: Conversions, Next: RTL Declarations, Prev: Vector Operations, Up: RTL + +10.13 Conversions +================= + +All conversions between machine modes must be represented by explicit +conversion operations. For example, an expression which is the sum of +a byte and a full word cannot be written as `(plus:SI (reg:QI 34) +(reg:SI 80))' because the `plus' operation requires two operands of the +same machine mode. Therefore, the byte-sized operand is enclosed in a +conversion operation, as in + + (plus:SI (sign_extend:SI (reg:QI 34)) (reg:SI 80)) + + The conversion operation is not a mere placeholder, because there may +be more than one way of converting from a given starting mode to the +desired final mode. The conversion operation code says how to do it. + + For all conversion operations, X must not be `VOIDmode' because the +mode in which to do the conversion would not be known. The conversion +must either be done at compile-time or X must be placed into a register. + +`(sign_extend:M X)' + Represents the result of sign-extending the value X to machine + mode M. M must be a fixed-point mode and X a fixed-point value of + a mode narrower than M. + +`(zero_extend:M X)' + Represents the result of zero-extending the value X to machine + mode M. M must be a fixed-point mode and X a fixed-point value of + a mode narrower than M. + +`(float_extend:M X)' + Represents the result of extending the value X to machine mode M. + M must be a floating point mode and X a floating point value of a + mode narrower than M. + +`(truncate:M X)' + Represents the result of truncating the value X to machine mode M. + M must be a fixed-point mode and X a fixed-point value of a mode + wider than M. + +`(ss_truncate:M X)' + Represents the result of truncating the value X to machine mode M, + using signed saturation in the case of overflow. Both M and the + mode of X must be fixed-point modes. + +`(us_truncate:M X)' + Represents the result of truncating the value X to machine mode M, + using unsigned saturation in the case of overflow. Both M and the + mode of X must be fixed-point modes. + +`(float_truncate:M X)' + Represents the result of truncating the value X to machine mode M. + M must be a floating point mode and X a floating point value of a + mode wider than M. + +`(float:M X)' + Represents the result of converting fixed point value X, regarded + as signed, to floating point mode M. + +`(unsigned_float:M X)' + Represents the result of converting fixed point value X, regarded + as unsigned, to floating point mode M. + +`(fix:M X)' + When M is a floating-point mode, represents the result of + converting floating point value X (valid for mode M) to an + integer, still represented in floating point mode M, by rounding + towards zero. + + When M is a fixed-point mode, represents the result of converting + floating point value X to mode M, regarded as signed. How + rounding is done is not specified, so this operation may be used + validly in compiling C code only for integer-valued operands. + +`(unsigned_fix:M X)' + Represents the result of converting floating point value X to + fixed point mode M, regarded as unsigned. How rounding is done is + not specified. + +`(fract_convert:M X)' + Represents the result of converting fixed-point value X to + fixed-point mode M, signed integer value X to fixed-point mode M, + floating-point value X to fixed-point mode M, fixed-point value X + to integer mode M regarded as signed, or fixed-point value X to + floating-point mode M. When overflows or underflows happen, the + results are undefined. + +`(sat_fract:M X)' + Represents the result of converting fixed-point value X to + fixed-point mode M, signed integer value X to fixed-point mode M, + or floating-point value X to fixed-point mode M. When overflows + or underflows happen, the results are saturated to the maximum or + the minimum. + +`(unsigned_fract_convert:M X)' + Represents the result of converting fixed-point value X to integer + mode M regarded as unsigned, or unsigned integer value X to + fixed-point mode M. When overflows or underflows happen, the + results are undefined. + +`(unsigned_sat_fract:M X)' + Represents the result of converting unsigned integer value X to + fixed-point mode M. When overflows or underflows happen, the + results are saturated to the maximum or the minimum. + + +File: gccint.info, Node: RTL Declarations, Next: Side Effects, Prev: Conversions, Up: RTL + +10.14 Declarations +================== + +Declaration expression codes do not represent arithmetic operations but +rather state assertions about their operands. + +`(strict_low_part (subreg:M (reg:N R) 0))' + This expression code is used in only one context: as the + destination operand of a `set' expression. In addition, the + operand of this expression must be a non-paradoxical `subreg' + expression. + + The presence of `strict_low_part' says that the part of the + register which is meaningful in mode N, but is not part of mode M, + is not to be altered. Normally, an assignment to such a subreg is + allowed to have undefined effects on the rest of the register when + M is less than a word. + + +File: gccint.info, Node: Side Effects, Next: Incdec, Prev: RTL Declarations, Up: RTL + +10.15 Side Effect Expressions +============================= + +The expression codes described so far represent values, not actions. +But machine instructions never produce values; they are meaningful only +for their side effects on the state of the machine. Special expression +codes are used to represent side effects. + + The body of an instruction is always one of these side effect codes; +the codes described above, which represent values, appear only as the +operands of these. + +`(set LVAL X)' + Represents the action of storing the value of X into the place + represented by LVAL. LVAL must be an expression representing a + place that can be stored in: `reg' (or `subreg', `strict_low_part' + or `zero_extract'), `mem', `pc', `parallel', or `cc0'. + + If LVAL is a `reg', `subreg' or `mem', it has a machine mode; then + X must be valid for that mode. + + If LVAL is a `reg' whose machine mode is less than the full width + of the register, then it means that the part of the register + specified by the machine mode is given the specified value and the + rest of the register receives an undefined value. Likewise, if + LVAL is a `subreg' whose machine mode is narrower than the mode of + the register, the rest of the register can be changed in an + undefined way. + + If LVAL is a `strict_low_part' of a subreg, then the part of the + register specified by the machine mode of the `subreg' is given + the value X and the rest of the register is not changed. + + If LVAL is a `zero_extract', then the referenced part of the + bit-field (a memory or register reference) specified by the + `zero_extract' is given the value X and the rest of the bit-field + is not changed. Note that `sign_extract' can not appear in LVAL. + + If LVAL is `(cc0)', it has no machine mode, and X may be either a + `compare' expression or a value that may have any mode. The + latter case represents a "test" instruction. The expression `(set + (cc0) (reg:M N))' is equivalent to `(set (cc0) (compare (reg:M N) + (const_int 0)))'. Use the former expression to save space during + the compilation. + + If LVAL is a `parallel', it is used to represent the case of a + function returning a structure in multiple registers. Each element + of the `parallel' is an `expr_list' whose first operand is a `reg' + and whose second operand is a `const_int' representing the offset + (in bytes) into the structure at which the data in that register + corresponds. The first element may be null to indicate that the + structure is also passed partly in memory. + + If LVAL is `(pc)', we have a jump instruction, and the + possibilities for X are very limited. It may be a `label_ref' + expression (unconditional jump). It may be an `if_then_else' + (conditional jump), in which case either the second or the third + operand must be `(pc)' (for the case which does not jump) and the + other of the two must be a `label_ref' (for the case which does + jump). X may also be a `mem' or `(plus:SI (pc) Y)', where Y may + be a `reg' or a `mem'; these unusual patterns are used to + represent jumps through branch tables. + + If LVAL is neither `(cc0)' nor `(pc)', the mode of LVAL must not + be `VOIDmode' and the mode of X must be valid for the mode of LVAL. + + LVAL is customarily accessed with the `SET_DEST' macro and X with + the `SET_SRC' macro. + +`(return)' + As the sole expression in a pattern, represents a return from the + current function, on machines where this can be done with one + instruction, such as VAXen. On machines where a multi-instruction + "epilogue" must be executed in order to return from the function, + returning is done by jumping to a label which precedes the + epilogue, and the `return' expression code is never used. + + Inside an `if_then_else' expression, represents the value to be + placed in `pc' to return to the caller. + + Note that an insn pattern of `(return)' is logically equivalent to + `(set (pc) (return))', but the latter form is never used. + +`(call FUNCTION NARGS)' + Represents a function call. FUNCTION is a `mem' expression whose + address is the address of the function to be called. NARGS is an + expression which can be used for two purposes: on some machines it + represents the number of bytes of stack argument; on others, it + represents the number of argument registers. + + Each machine has a standard machine mode which FUNCTION must have. + The machine description defines macro `FUNCTION_MODE' to expand + into the requisite mode name. The purpose of this mode is to + specify what kind of addressing is allowed, on machines where the + allowed kinds of addressing depend on the machine mode being + addressed. + +`(clobber X)' + Represents the storing or possible storing of an unpredictable, + undescribed value into X, which must be a `reg', `scratch', + `parallel' or `mem' expression. + + One place this is used is in string instructions that store + standard values into particular hard registers. It may not be + worth the trouble to describe the values that are stored, but it + is essential to inform the compiler that the registers will be + altered, lest it attempt to keep data in them across the string + instruction. + + If X is `(mem:BLK (const_int 0))' or `(mem:BLK (scratch))', it + means that all memory locations must be presumed clobbered. If X + is a `parallel', it has the same meaning as a `parallel' in a + `set' expression. + + Note that the machine description classifies certain hard + registers as "call-clobbered". All function call instructions are + assumed by default to clobber these registers, so there is no need + to use `clobber' expressions to indicate this fact. Also, each + function call is assumed to have the potential to alter any memory + location, unless the function is declared `const'. + + If the last group of expressions in a `parallel' are each a + `clobber' expression whose arguments are `reg' or `match_scratch' + (*note RTL Template::) expressions, the combiner phase can add the + appropriate `clobber' expressions to an insn it has constructed + when doing so will cause a pattern to be matched. + + This feature can be used, for example, on a machine that whose + multiply and add instructions don't use an MQ register but which + has an add-accumulate instruction that does clobber the MQ + register. Similarly, a combined instruction might require a + temporary register while the constituent instructions might not. + + When a `clobber' expression for a register appears inside a + `parallel' with other side effects, the register allocator + guarantees that the register is unoccupied both before and after + that insn if it is a hard register clobber. For pseudo-register + clobber, the register allocator and the reload pass do not assign + the same hard register to the clobber and the input operands if + there is an insn alternative containing the `&' constraint (*note + Modifiers::) for the clobber and the hard register is in register + classes of the clobber in the alternative. You can clobber either + a specific hard register, a pseudo register, or a `scratch' + expression; in the latter two cases, GCC will allocate a hard + register that is available there for use as a temporary. + + For instructions that require a temporary register, you should use + `scratch' instead of a pseudo-register because this will allow the + combiner phase to add the `clobber' when required. You do this by + coding (`clobber' (`match_scratch' ...)). If you do clobber a + pseudo register, use one which appears nowhere else--generate a + new one each time. Otherwise, you may confuse CSE. + + There is one other known use for clobbering a pseudo register in a + `parallel': when one of the input operands of the insn is also + clobbered by the insn. In this case, using the same pseudo + register in the clobber and elsewhere in the insn produces the + expected results. + +`(use X)' + Represents the use of the value of X. It indicates that the value + in X at this point in the program is needed, even though it may + not be apparent why this is so. Therefore, the compiler will not + attempt to delete previous instructions whose only effect is to + store a value in X. X must be a `reg' expression. + + In some situations, it may be tempting to add a `use' of a + register in a `parallel' to describe a situation where the value + of a special register will modify the behavior of the instruction. + A hypothetical example might be a pattern for an addition that can + either wrap around or use saturating addition depending on the + value of a special control register: + + (parallel [(set (reg:SI 2) (unspec:SI [(reg:SI 3) + (reg:SI 4)] 0)) + (use (reg:SI 1))]) + + This will not work, several of the optimizers only look at + expressions locally; it is very likely that if you have multiple + insns with identical inputs to the `unspec', they will be + optimized away even if register 1 changes in between. + + This means that `use' can _only_ be used to describe that the + register is live. You should think twice before adding `use' + statements, more often you will want to use `unspec' instead. The + `use' RTX is most commonly useful to describe that a fixed + register is implicitly used in an insn. It is also safe to use in + patterns where the compiler knows for other reasons that the result + of the whole pattern is variable, such as `movmemM' or `call' + patterns. + + During the reload phase, an insn that has a `use' as pattern can + carry a reg_equal note. These `use' insns will be deleted before + the reload phase exits. + + During the delayed branch scheduling phase, X may be an insn. + This indicates that X previously was located at this place in the + code and its data dependencies need to be taken into account. + These `use' insns will be deleted before the delayed branch + scheduling phase exits. + +`(parallel [X0 X1 ...])' + Represents several side effects performed in parallel. The square + brackets stand for a vector; the operand of `parallel' is a vector + of expressions. X0, X1 and so on are individual side effect + expressions--expressions of code `set', `call', `return', + `clobber' or `use'. + + "In parallel" means that first all the values used in the + individual side-effects are computed, and second all the actual + side-effects are performed. For example, + + (parallel [(set (reg:SI 1) (mem:SI (reg:SI 1))) + (set (mem:SI (reg:SI 1)) (reg:SI 1))]) + + says unambiguously that the values of hard register 1 and the + memory location addressed by it are interchanged. In both places + where `(reg:SI 1)' appears as a memory address it refers to the + value in register 1 _before_ the execution of the insn. + + It follows that it is _incorrect_ to use `parallel' and expect the + result of one `set' to be available for the next one. For + example, people sometimes attempt to represent a jump-if-zero + instruction this way: + + (parallel [(set (cc0) (reg:SI 34)) + (set (pc) (if_then_else + (eq (cc0) (const_int 0)) + (label_ref ...) + (pc)))]) + + But this is incorrect, because it says that the jump condition + depends on the condition code value _before_ this instruction, not + on the new value that is set by this instruction. + + Peephole optimization, which takes place together with final + assembly code output, can produce insns whose patterns consist of + a `parallel' whose elements are the operands needed to output the + resulting assembler code--often `reg', `mem' or constant + expressions. This would not be well-formed RTL at any other stage + in compilation, but it is ok then because no further optimization + remains to be done. However, the definition of the macro + `NOTICE_UPDATE_CC', if any, must deal with such insns if you + define any peephole optimizations. + +`(cond_exec [COND EXPR])' + Represents a conditionally executed expression. The EXPR is + executed only if the COND is nonzero. The COND expression must + not have side-effects, but the EXPR may very well have + side-effects. + +`(sequence [INSNS ...])' + Represents a sequence of insns. Each of the INSNS that appears in + the vector is suitable for appearing in the chain of insns, so it + must be an `insn', `jump_insn', `call_insn', `code_label', + `barrier' or `note'. + + A `sequence' RTX is never placed in an actual insn during RTL + generation. It represents the sequence of insns that result from a + `define_expand' _before_ those insns are passed to `emit_insn' to + insert them in the chain of insns. When actually inserted, the + individual sub-insns are separated out and the `sequence' is + forgotten. + + After delay-slot scheduling is completed, an insn and all the + insns that reside in its delay slots are grouped together into a + `sequence'. The insn requiring the delay slot is the first insn + in the vector; subsequent insns are to be placed in the delay slot. + + `INSN_ANNULLED_BRANCH_P' is set on an insn in a delay slot to + indicate that a branch insn should be used that will conditionally + annul the effect of the insns in the delay slots. In such a case, + `INSN_FROM_TARGET_P' indicates that the insn is from the target of + the branch and should be executed only if the branch is taken; + otherwise the insn should be executed only if the branch is not + taken. *Note Delay Slots::. + + These expression codes appear in place of a side effect, as the body of +an insn, though strictly speaking they do not always describe side +effects as such: + +`(asm_input S)' + Represents literal assembler code as described by the string S. + +`(unspec [OPERANDS ...] INDEX)' +`(unspec_volatile [OPERANDS ...] INDEX)' + Represents a machine-specific operation on OPERANDS. INDEX + selects between multiple machine-specific operations. + `unspec_volatile' is used for volatile operations and operations + that may trap; `unspec' is used for other operations. + + These codes may appear inside a `pattern' of an insn, inside a + `parallel', or inside an expression. + +`(addr_vec:M [LR0 LR1 ...])' + Represents a table of jump addresses. The vector elements LR0, + etc., are `label_ref' expressions. The mode M specifies how much + space is given to each address; normally M would be `Pmode'. + +`(addr_diff_vec:M BASE [LR0 LR1 ...] MIN MAX FLAGS)' + Represents a table of jump addresses expressed as offsets from + BASE. The vector elements LR0, etc., are `label_ref' expressions + and so is BASE. The mode M specifies how much space is given to + each address-difference. MIN and MAX are set up by branch + shortening and hold a label with a minimum and a maximum address, + respectively. FLAGS indicates the relative position of BASE, MIN + and MAX to the containing insn and of MIN and MAX to BASE. See + rtl.def for details. + +`(prefetch:M ADDR RW LOCALITY)' + Represents prefetch of memory at address ADDR. Operand RW is 1 if + the prefetch is for data to be written, 0 otherwise; targets that + do not support write prefetches should treat this as a normal + prefetch. Operand LOCALITY specifies the amount of temporal + locality; 0 if there is none or 1, 2, or 3 for increasing levels + of temporal locality; targets that do not support locality hints + should ignore this. + + This insn is used to minimize cache-miss latency by moving data + into a cache before it is accessed. It should use only + non-faulting data prefetch instructions. + + +File: gccint.info, Node: Incdec, Next: Assembler, Prev: Side Effects, Up: RTL + +10.16 Embedded Side-Effects on Addresses +======================================== + +Six special side-effect expression codes appear as memory addresses. + +`(pre_dec:M X)' + Represents the side effect of decrementing X by a standard amount + and represents also the value that X has after being decremented. + X must be a `reg' or `mem', but most machines allow only a `reg'. + M must be the machine mode for pointers on the machine in use. + The amount X is decremented by is the length in bytes of the + machine mode of the containing memory reference of which this + expression serves as the address. Here is an example of its use: + + (mem:DF (pre_dec:SI (reg:SI 39))) + + This says to decrement pseudo register 39 by the length of a + `DFmode' value and use the result to address a `DFmode' value. + +`(pre_inc:M X)' + Similar, but specifies incrementing X instead of decrementing it. + +`(post_dec:M X)' + Represents the same side effect as `pre_dec' but a different + value. The value represented here is the value X has before being + decremented. + +`(post_inc:M X)' + Similar, but specifies incrementing X instead of decrementing it. + +`(post_modify:M X Y)' + Represents the side effect of setting X to Y and represents X + before X is modified. X must be a `reg' or `mem', but most + machines allow only a `reg'. M must be the machine mode for + pointers on the machine in use. + + The expression Y must be one of three forms: `(plus:M X Z)', + `(minus:M X Z)', or `(plus:M X I)', where Z is an index register + and I is a constant. + + Here is an example of its use: + + (mem:SF (post_modify:SI (reg:SI 42) (plus (reg:SI 42) + (reg:SI 48)))) + + This says to modify pseudo register 42 by adding the contents of + pseudo register 48 to it, after the use of what ever 42 points to. + +`(pre_modify:M X EXPR)' + Similar except side effects happen before the use. + + These embedded side effect expressions must be used with care. +Instruction patterns may not use them. Until the `flow' pass of the +compiler, they may occur only to represent pushes onto the stack. The +`flow' pass finds cases where registers are incremented or decremented +in one instruction and used as an address shortly before or after; +these cases are then transformed to use pre- or post-increment or +-decrement. + + If a register used as the operand of these expressions is used in +another address in an insn, the original value of the register is used. +Uses of the register outside of an address are not permitted within the +same insn as a use in an embedded side effect expression because such +insns behave differently on different machines and hence must be treated +as ambiguous and disallowed. + + An instruction that can be represented with an embedded side effect +could also be represented using `parallel' containing an additional +`set' to describe how the address register is altered. This is not +done because machines that allow these operations at all typically +allow them wherever a memory address is called for. Describing them as +additional parallel stores would require doubling the number of entries +in the machine description. + + +File: gccint.info, Node: Assembler, Next: Debug Information, Prev: Incdec, Up: RTL + +10.17 Assembler Instructions as Expressions +=========================================== + +The RTX code `asm_operands' represents a value produced by a +user-specified assembler instruction. It is used to represent an `asm' +statement with arguments. An `asm' statement with a single output +operand, like this: + + asm ("foo %1,%2,%0" : "=a" (outputvar) : "g" (x + y), "di" (*z)); + +is represented using a single `asm_operands' RTX which represents the +value that is stored in `outputvar': + + (set RTX-FOR-OUTPUTVAR + (asm_operands "foo %1,%2,%0" "a" 0 + [RTX-FOR-ADDITION-RESULT RTX-FOR-*Z] + [(asm_input:M1 "g") + (asm_input:M2 "di")])) + +Here the operands of the `asm_operands' RTX are the assembler template +string, the output-operand's constraint, the index-number of the output +operand among the output operands specified, a vector of input operand +RTX's, and a vector of input-operand modes and constraints. The mode +M1 is the mode of the sum `x+y'; M2 is that of `*z'. + + When an `asm' statement has multiple output values, its insn has +several such `set' RTX's inside of a `parallel'. Each `set' contains +an `asm_operands'; all of these share the same assembler template and +vectors, but each contains the constraint for the respective output +operand. They are also distinguished by the output-operand index +number, which is 0, 1, ... for successive output operands. + + +File: gccint.info, Node: Debug Information, Next: Insns, Prev: Assembler, Up: RTL + +10.18 Variable Location Debug Information in RTL +================================================ + +Variable tracking relies on `MEM_EXPR' and `REG_EXPR' annotations to +determine what user variables memory and register references refer to. + + Variable tracking at assignments uses these notes only when they refer +to variables that live at fixed locations (e.g., addressable variables, +global non-automatic variables). For variables whose location may +vary, it relies on the following types of notes. + +`(var_location:MODE VAR EXP STAT)' + Binds variable `var', a tree, to value EXP, an RTL expression. It + appears only in `NOTE_INSN_VAR_LOCATION' and `DEBUG_INSN's, with + slightly different meanings. MODE, if present, represents the + mode of EXP, which is useful if it is a modeless expression. STAT + is only meaningful in notes, indicating whether the variable is + known to be initialized or uninitialized. + +`(debug_expr:MODE DECL)' + Stands for the value bound to the `DEBUG_EXPR_DECL' DECL, that + points back to it, within value expressions in `VAR_LOCATION' + nodes. + + + +File: gccint.info, Node: Insns, Next: Calls, Prev: Debug Information, Up: RTL + +10.19 Insns +=========== + +The RTL representation of the code for a function is a doubly-linked +chain of objects called "insns". Insns are expressions with special +codes that are used for no other purpose. Some insns are actual +instructions; others represent dispatch tables for `switch' statements; +others represent labels to jump to or various sorts of declarative +information. + + In addition to its own specific data, each insn must have a unique +id-number that distinguishes it from all other insns in the current +function (after delayed branch scheduling, copies of an insn with the +same id-number may be present in multiple places in a function, but +these copies will always be identical and will only appear inside a +`sequence'), and chain pointers to the preceding and following insns. +These three fields occupy the same position in every insn, independent +of the expression code of the insn. They could be accessed with `XEXP' +and `XINT', but instead three special macros are always used: + +`INSN_UID (I)' + Accesses the unique id of insn I. + +`PREV_INSN (I)' + Accesses the chain pointer to the insn preceding I. If I is the + first insn, this is a null pointer. + +`NEXT_INSN (I)' + Accesses the chain pointer to the insn following I. If I is the + last insn, this is a null pointer. + + The first insn in the chain is obtained by calling `get_insns'; the +last insn is the result of calling `get_last_insn'. Within the chain +delimited by these insns, the `NEXT_INSN' and `PREV_INSN' pointers must +always correspond: if INSN is not the first insn, + + NEXT_INSN (PREV_INSN (INSN)) == INSN + +is always true and if INSN is not the last insn, + + PREV_INSN (NEXT_INSN (INSN)) == INSN + +is always true. + + After delay slot scheduling, some of the insns in the chain might be +`sequence' expressions, which contain a vector of insns. The value of +`NEXT_INSN' in all but the last of these insns is the next insn in the +vector; the value of `NEXT_INSN' of the last insn in the vector is the +same as the value of `NEXT_INSN' for the `sequence' in which it is +contained. Similar rules apply for `PREV_INSN'. + + This means that the above invariants are not necessarily true for insns +inside `sequence' expressions. Specifically, if INSN is the first insn +in a `sequence', `NEXT_INSN (PREV_INSN (INSN))' is the insn containing +the `sequence' expression, as is the value of `PREV_INSN (NEXT_INSN +(INSN))' if INSN is the last insn in the `sequence' expression. You +can use these expressions to find the containing `sequence' expression. + + Every insn has one of the following expression codes: + +`insn' + The expression code `insn' is used for instructions that do not + jump and do not do function calls. `sequence' expressions are + always contained in insns with code `insn' even if one of those + insns should jump or do function calls. + + Insns with code `insn' have four additional fields beyond the three + mandatory ones listed above. These four are described in a table + below. + +`jump_insn' + The expression code `jump_insn' is used for instructions that may + jump (or, more generally, may contain `label_ref' expressions to + which `pc' can be set in that instruction). If there is an + instruction to return from the current function, it is recorded as + a `jump_insn'. + + `jump_insn' insns have the same extra fields as `insn' insns, + accessed in the same way and in addition contain a field + `JUMP_LABEL' which is defined once jump optimization has completed. + + For simple conditional and unconditional jumps, this field contains + the `code_label' to which this insn will (possibly conditionally) + branch. In a more complex jump, `JUMP_LABEL' records one of the + labels that the insn refers to; other jump target labels are + recorded as `REG_LABEL_TARGET' notes. The exception is `addr_vec' + and `addr_diff_vec', where `JUMP_LABEL' is `NULL_RTX' and the only + way to find the labels is to scan the entire body of the insn. + + Return insns count as jumps, but since they do not refer to any + labels, their `JUMP_LABEL' is `NULL_RTX'. + +`call_insn' + The expression code `call_insn' is used for instructions that may + do function calls. It is important to distinguish these + instructions because they imply that certain registers and memory + locations may be altered unpredictably. + + `call_insn' insns have the same extra fields as `insn' insns, + accessed in the same way and in addition contain a field + `CALL_INSN_FUNCTION_USAGE', which contains a list (chain of + `expr_list' expressions) containing `use' and `clobber' + expressions that denote hard registers and `MEM's used or + clobbered by the called function. + + A `MEM' generally points to a stack slots in which arguments passed + to the libcall by reference (*note TARGET_PASS_BY_REFERENCE: + Register Arguments.) are stored. If the argument is caller-copied + (*note TARGET_CALLEE_COPIES: Register Arguments.), the stack slot + will be mentioned in `CLOBBER' and `USE' entries; if it's + callee-copied, only a `USE' will appear, and the `MEM' may point + to addresses that are not stack slots. + + `CLOBBER'ed registers in this list augment registers specified in + `CALL_USED_REGISTERS' (*note Register Basics::). + +`code_label' + A `code_label' insn represents a label that a jump insn can jump + to. It contains two special fields of data in addition to the + three standard ones. `CODE_LABEL_NUMBER' is used to hold the + "label number", a number that identifies this label uniquely among + all the labels in the compilation (not just in the current + function). Ultimately, the label is represented in the assembler + output as an assembler label, usually of the form `LN' where N is + the label number. + + When a `code_label' appears in an RTL expression, it normally + appears within a `label_ref' which represents the address of the + label, as a number. + + Besides as a `code_label', a label can also be represented as a + `note' of type `NOTE_INSN_DELETED_LABEL'. + + The field `LABEL_NUSES' is only defined once the jump optimization + phase is completed. It contains the number of times this label is + referenced in the current function. + + The field `LABEL_KIND' differentiates four different types of + labels: `LABEL_NORMAL', `LABEL_STATIC_ENTRY', + `LABEL_GLOBAL_ENTRY', and `LABEL_WEAK_ENTRY'. The only labels + that do not have type `LABEL_NORMAL' are "alternate entry points" + to the current function. These may be static (visible only in the + containing translation unit), global (exposed to all translation + units), or weak (global, but can be overridden by another symbol + with the same name). + + Much of the compiler treats all four kinds of label identically. + Some of it needs to know whether or not a label is an alternate + entry point; for this purpose, the macro `LABEL_ALT_ENTRY_P' is + provided. It is equivalent to testing whether `LABEL_KIND (label) + == LABEL_NORMAL'. The only place that cares about the distinction + between static, global, and weak alternate entry points, besides + the front-end code that creates them, is the function + `output_alternate_entry_point', in `final.c'. + + To set the kind of a label, use the `SET_LABEL_KIND' macro. + +`barrier' + Barriers are placed in the instruction stream when control cannot + flow past them. They are placed after unconditional jump + instructions to indicate that the jumps are unconditional and + after calls to `volatile' functions, which do not return (e.g., + `exit'). They contain no information beyond the three standard + fields. + +`note' + `note' insns are used to represent additional debugging and + declarative information. They contain two nonstandard fields, an + integer which is accessed with the macro `NOTE_LINE_NUMBER' and a + string accessed with `NOTE_SOURCE_FILE'. + + If `NOTE_LINE_NUMBER' is positive, the note represents the + position of a source line and `NOTE_SOURCE_FILE' is the source + file name that the line came from. These notes control generation + of line number data in the assembler output. + + Otherwise, `NOTE_LINE_NUMBER' is not really a line number but a + code with one of the following values (and `NOTE_SOURCE_FILE' must + contain a null pointer): + + `NOTE_INSN_DELETED' + Such a note is completely ignorable. Some passes of the + compiler delete insns by altering them into notes of this + kind. + + `NOTE_INSN_DELETED_LABEL' + This marks what used to be a `code_label', but was not used + for other purposes than taking its address and was + transformed to mark that no code jumps to it. + + `NOTE_INSN_BLOCK_BEG' + `NOTE_INSN_BLOCK_END' + These types of notes indicate the position of the beginning + and end of a level of scoping of variable names. They + control the output of debugging information. + + `NOTE_INSN_EH_REGION_BEG' + `NOTE_INSN_EH_REGION_END' + These types of notes indicate the position of the beginning + and end of a level of scoping for exception handling. + `NOTE_BLOCK_NUMBER' identifies which `CODE_LABEL' or `note' + of type `NOTE_INSN_DELETED_LABEL' is associated with the + given region. + + `NOTE_INSN_LOOP_BEG' + `NOTE_INSN_LOOP_END' + These types of notes indicate the position of the beginning + and end of a `while' or `for' loop. They enable the loop + optimizer to find loops quickly. + + `NOTE_INSN_LOOP_CONT' + Appears at the place in a loop that `continue' statements + jump to. + + `NOTE_INSN_LOOP_VTOP' + This note indicates the place in a loop where the exit test + begins for those loops in which the exit test has been + duplicated. This position becomes another virtual start of + the loop when considering loop invariants. + + `NOTE_INSN_FUNCTION_BEG' + Appears at the start of the function body, after the function + prologue. + + `NOTE_INSN_VAR_LOCATION' + This note is used to generate variable location debugging + information. It indicates that the user variable in its + `VAR_LOCATION' operand is at the location given in the RTL + expression, or holds a value that can be computed by + evaluating the RTL expression from that static point in the + program up to the next such note for the same user variable. + + + These codes are printed symbolically when they appear in debugging + dumps. + +`debug_insn' + The expression code `debug_insn' is used for pseudo-instructions + that hold debugging information for variable tracking at + assignments (see `-fvar-tracking-assignments' option). They are + the RTL representation of `GIMPLE_DEBUG' statements (*note + `GIMPLE_DEBUG'::), with a `VAR_LOCATION' operand that binds a user + variable tree to an RTL representation of the `value' in the + corresponding statement. A `DEBUG_EXPR' in it stands for the + value bound to the corresponding `DEBUG_EXPR_DECL'. + + Throughout optimization passes, binding information is kept in + pseudo-instruction form, so that, unlike notes, it gets the same + treatment and adjustments that regular instructions would. It is + the variable tracking pass that turns these pseudo-instructions + into var location notes, analyzing control flow, value + equivalences and changes to registers and memory referenced in + value expressions, propagating the values of debug temporaries and + determining expressions that can be used to compute the value of + each user variable at as many points (ranges, actually) in the + program as possible. + + Unlike `NOTE_INSN_VAR_LOCATION', the value expression in an + `INSN_VAR_LOCATION' denotes a value at that specific point in the + program, rather than an expression that can be evaluated at any + later point before an overriding `VAR_LOCATION' is encountered. + E.g., if a user variable is bound to a `REG' and then a subsequent + insn modifies the `REG', the note location would keep mapping the + user variable to the register across the insn, whereas the insn + location would keep the variable bound to the value, so that the + variable tracking pass would emit another location note for the + variable at the point in which the register is modified. + + + The machine mode of an insn is normally `VOIDmode', but some phases +use the mode for various purposes. + + The common subexpression elimination pass sets the mode of an insn to +`QImode' when it is the first insn in a block that has already been +processed. + + The second Haifa scheduling pass, for targets that can multiple issue, +sets the mode of an insn to `TImode' when it is believed that the +instruction begins an issue group. That is, when the instruction +cannot issue simultaneously with the previous. This may be relied on +by later passes, in particular machine-dependent reorg. + + Here is a table of the extra fields of `insn', `jump_insn' and +`call_insn' insns: + +`PATTERN (I)' + An expression for the side effect performed by this insn. This + must be one of the following codes: `set', `call', `use', + `clobber', `return', `asm_input', `asm_output', `addr_vec', + `addr_diff_vec', `trap_if', `unspec', `unspec_volatile', + `parallel', `cond_exec', or `sequence'. If it is a `parallel', + each element of the `parallel' must be one these codes, except that + `parallel' expressions cannot be nested and `addr_vec' and + `addr_diff_vec' are not permitted inside a `parallel' expression. + +`INSN_CODE (I)' + An integer that says which pattern in the machine description + matches this insn, or -1 if the matching has not yet been + attempted. + + Such matching is never attempted and this field remains -1 on an + insn whose pattern consists of a single `use', `clobber', + `asm_input', `addr_vec' or `addr_diff_vec' expression. + + Matching is also never attempted on insns that result from an `asm' + statement. These contain at least one `asm_operands' expression. + The function `asm_noperands' returns a non-negative value for such + insns. + + In the debugging output, this field is printed as a number + followed by a symbolic representation that locates the pattern in + the `md' file as some small positive or negative offset from a + named pattern. + +`LOG_LINKS (I)' + A list (chain of `insn_list' expressions) giving information about + dependencies between instructions within a basic block. Neither a + jump nor a label may come between the related insns. These are + only used by the schedulers and by combine. This is a deprecated + data structure. Def-use and use-def chains are now preferred. + +`REG_NOTES (I)' + A list (chain of `expr_list' and `insn_list' expressions) giving + miscellaneous information about the insn. It is often information + pertaining to the registers used in this insn. + + The `LOG_LINKS' field of an insn is a chain of `insn_list' +expressions. Each of these has two operands: the first is an insn, and +the second is another `insn_list' expression (the next one in the +chain). The last `insn_list' in the chain has a null pointer as second +operand. The significant thing about the chain is which insns appear +in it (as first operands of `insn_list' expressions). Their order is +not significant. + + This list is originally set up by the flow analysis pass; it is a null +pointer until then. Flow only adds links for those data dependencies +which can be used for instruction combination. For each insn, the flow +analysis pass adds a link to insns which store into registers values +that are used for the first time in this insn. + + The `REG_NOTES' field of an insn is a chain similar to the `LOG_LINKS' +field but it includes `expr_list' expressions in addition to +`insn_list' expressions. There are several kinds of register notes, +which are distinguished by the machine mode, which in a register note +is really understood as being an `enum reg_note'. The first operand OP +of the note is data whose meaning depends on the kind of note. + + The macro `REG_NOTE_KIND (X)' returns the kind of register note. Its +counterpart, the macro `PUT_REG_NOTE_KIND (X, NEWKIND)' sets the +register note type of X to be NEWKIND. + + Register notes are of three classes: They may say something about an +input to an insn, they may say something about an output of an insn, or +they may create a linkage between two insns. There are also a set of +values that are only used in `LOG_LINKS'. + + These register notes annotate inputs to an insn: + +`REG_DEAD' + The value in OP dies in this insn; that is to say, altering the + value immediately after this insn would not affect the future + behavior of the program. + + It does not follow that the register OP has no useful value after + this insn since OP is not necessarily modified by this insn. + Rather, no subsequent instruction uses the contents of OP. + +`REG_UNUSED' + The register OP being set by this insn will not be used in a + subsequent insn. This differs from a `REG_DEAD' note, which + indicates that the value in an input will not be used subsequently. + These two notes are independent; both may be present for the same + register. + +`REG_INC' + The register OP is incremented (or decremented; at this level + there is no distinction) by an embedded side effect inside this + insn. This means it appears in a `post_inc', `pre_inc', + `post_dec' or `pre_dec' expression. + +`REG_NONNEG' + The register OP is known to have a nonnegative value when this + insn is reached. This is used so that decrement and branch until + zero instructions, such as the m68k dbra, can be matched. + + The `REG_NONNEG' note is added to insns only if the machine + description has a `decrement_and_branch_until_zero' pattern. + +`REG_LABEL_OPERAND' + This insn uses OP, a `code_label' or a `note' of type + `NOTE_INSN_DELETED_LABEL', but is not a `jump_insn', or it is a + `jump_insn' that refers to the operand as an ordinary operand. + The label may still eventually be a jump target, but if so in an + indirect jump in a subsequent insn. The presence of this note + allows jump optimization to be aware that OP is, in fact, being + used, and flow optimization to build an accurate flow graph. + +`REG_LABEL_TARGET' + This insn is a `jump_insn' but not an `addr_vec' or + `addr_diff_vec'. It uses OP, a `code_label' as a direct or + indirect jump target. Its purpose is similar to that of + `REG_LABEL_OPERAND'. This note is only present if the insn has + multiple targets; the last label in the insn (in the highest + numbered insn-field) goes into the `JUMP_LABEL' field and does not + have a `REG_LABEL_TARGET' note. *Note JUMP_LABEL: Insns. + +`REG_CROSSING_JUMP' + This insn is a branching instruction (either an unconditional jump + or an indirect jump) which crosses between hot and cold sections, + which could potentially be very far apart in the executable. The + presence of this note indicates to other optimizations that this + branching instruction should not be "collapsed" into a simpler + branching construct. It is used when the optimization to + partition basic blocks into hot and cold sections is turned on. + +`REG_SETJMP' + Appears attached to each `CALL_INSN' to `setjmp' or a related + function. + + The following notes describe attributes of outputs of an insn: + +`REG_EQUIV' +`REG_EQUAL' + This note is only valid on an insn that sets only one register and + indicates that that register will be equal to OP at run time; the + scope of this equivalence differs between the two types of notes. + The value which the insn explicitly copies into the register may + look different from OP, but they will be equal at run time. If the + output of the single `set' is a `strict_low_part' expression, the + note refers to the register that is contained in `SUBREG_REG' of + the `subreg' expression. + + For `REG_EQUIV', the register is equivalent to OP throughout the + entire function, and could validly be replaced in all its + occurrences by OP. ("Validly" here refers to the data flow of the + program; simple replacement may make some insns invalid.) For + example, when a constant is loaded into a register that is never + assigned any other value, this kind of note is used. + + When a parameter is copied into a pseudo-register at entry to a + function, a note of this kind records that the register is + equivalent to the stack slot where the parameter was passed. + Although in this case the register may be set by other insns, it + is still valid to replace the register by the stack slot + throughout the function. + + A `REG_EQUIV' note is also used on an instruction which copies a + register parameter into a pseudo-register at entry to a function, + if there is a stack slot where that parameter could be stored. + Although other insns may set the pseudo-register, it is valid for + the compiler to replace the pseudo-register by stack slot + throughout the function, provided the compiler ensures that the + stack slot is properly initialized by making the replacement in + the initial copy instruction as well. This is used on machines + for which the calling convention allocates stack space for + register parameters. See `REG_PARM_STACK_SPACE' in *note Stack + Arguments::. + + In the case of `REG_EQUAL', the register that is set by this insn + will be equal to OP at run time at the end of this insn but not + necessarily elsewhere in the function. In this case, OP is + typically an arithmetic expression. For example, when a sequence + of insns such as a library call is used to perform an arithmetic + operation, this kind of note is attached to the insn that produces + or copies the final value. + + These two notes are used in different ways by the compiler passes. + `REG_EQUAL' is used by passes prior to register allocation (such as + common subexpression elimination and loop optimization) to tell + them how to think of that value. `REG_EQUIV' notes are used by + register allocation to indicate that there is an available + substitute expression (either a constant or a `mem' expression for + the location of a parameter on the stack) that may be used in + place of a register if insufficient registers are available. + + Except for stack homes for parameters, which are indicated by a + `REG_EQUIV' note and are not useful to the early optimization + passes and pseudo registers that are equivalent to a memory + location throughout their entire life, which is not detected until + later in the compilation, all equivalences are initially indicated + by an attached `REG_EQUAL' note. In the early stages of register + allocation, a `REG_EQUAL' note is changed into a `REG_EQUIV' note + if OP is a constant and the insn represents the only set of its + destination register. + + Thus, compiler passes prior to register allocation need only check + for `REG_EQUAL' notes and passes subsequent to register allocation + need only check for `REG_EQUIV' notes. + + These notes describe linkages between insns. They occur in pairs: one +insn has one of a pair of notes that points to a second insn, which has +the inverse note pointing back to the first insn. + +`REG_CC_SETTER' +`REG_CC_USER' + On machines that use `cc0', the insns which set and use `cc0' set + and use `cc0' are adjacent. However, when branch delay slot + filling is done, this may no longer be true. In this case a + `REG_CC_USER' note will be placed on the insn setting `cc0' to + point to the insn using `cc0' and a `REG_CC_SETTER' note will be + placed on the insn using `cc0' to point to the insn setting `cc0'. + + These values are only used in the `LOG_LINKS' field, and indicate the +type of dependency that each link represents. Links which indicate a +data dependence (a read after write dependence) do not use any code, +they simply have mode `VOIDmode', and are printed without any +descriptive text. + +`REG_DEP_TRUE' + This indicates a true dependence (a read after write dependence). + +`REG_DEP_OUTPUT' + This indicates an output dependence (a write after write + dependence). + +`REG_DEP_ANTI' + This indicates an anti dependence (a write after read dependence). + + + These notes describe information gathered from gcov profile data. They +are stored in the `REG_NOTES' field of an insn as an `expr_list'. + +`REG_BR_PROB' + This is used to specify the ratio of branches to non-branches of a + branch insn according to the profile data. The value is stored as + a value between 0 and REG_BR_PROB_BASE; larger values indicate a + higher probability that the branch will be taken. + +`REG_BR_PRED' + These notes are found in JUMP insns after delayed branch scheduling + has taken place. They indicate both the direction and the + likelihood of the JUMP. The format is a bitmask of ATTR_FLAG_* + values. + +`REG_FRAME_RELATED_EXPR' + This is used on an RTX_FRAME_RELATED_P insn wherein the attached + expression is used in place of the actual insn pattern. This is + done in cases where the pattern is either complex or misleading. + + For convenience, the machine mode in an `insn_list' or `expr_list' is +printed using these symbolic codes in debugging dumps. + + The only difference between the expression codes `insn_list' and +`expr_list' is that the first operand of an `insn_list' is assumed to +be an insn and is printed in debugging dumps as the insn's unique id; +the first operand of an `expr_list' is printed in the ordinary way as +an expression. + + +File: gccint.info, Node: Calls, Next: Sharing, Prev: Insns, Up: RTL + +10.20 RTL Representation of Function-Call Insns +=============================================== + +Insns that call subroutines have the RTL expression code `call_insn'. +These insns must satisfy special rules, and their bodies must use a +special RTL expression code, `call'. + + A `call' expression has two operands, as follows: + + (call (mem:FM ADDR) NBYTES) + +Here NBYTES is an operand that represents the number of bytes of +argument data being passed to the subroutine, FM is a machine mode +(which must equal as the definition of the `FUNCTION_MODE' macro in the +machine description) and ADDR represents the address of the subroutine. + + For a subroutine that returns no value, the `call' expression as shown +above is the entire body of the insn, except that the insn might also +contain `use' or `clobber' expressions. + + For a subroutine that returns a value whose mode is not `BLKmode', the +value is returned in a hard register. If this register's number is R, +then the body of the call insn looks like this: + + (set (reg:M R) + (call (mem:FM ADDR) NBYTES)) + +This RTL expression makes it clear (to the optimizer passes) that the +appropriate register receives a useful value in this insn. + + When a subroutine returns a `BLKmode' value, it is handled by passing +to the subroutine the address of a place to store the value. So the +call insn itself does not "return" any value, and it has the same RTL +form as a call that returns nothing. + + On some machines, the call instruction itself clobbers some register, +for example to contain the return address. `call_insn' insns on these +machines should have a body which is a `parallel' that contains both +the `call' expression and `clobber' expressions that indicate which +registers are destroyed. Similarly, if the call instruction requires +some register other than the stack pointer that is not explicitly +mentioned in its RTL, a `use' subexpression should mention that +register. + + Functions that are called are assumed to modify all registers listed in +the configuration macro `CALL_USED_REGISTERS' (*note Register Basics::) +and, with the exception of `const' functions and library calls, to +modify all of memory. + + Insns containing just `use' expressions directly precede the +`call_insn' insn to indicate which registers contain inputs to the +function. Similarly, if registers other than those in +`CALL_USED_REGISTERS' are clobbered by the called function, insns +containing a single `clobber' follow immediately after the call to +indicate which registers. + + +File: gccint.info, Node: Sharing, Next: Reading RTL, Prev: Calls, Up: RTL + +10.21 Structure Sharing Assumptions +=================================== + +The compiler assumes that certain kinds of RTL expressions are unique; +there do not exist two distinct objects representing the same value. +In other cases, it makes an opposite assumption: that no RTL expression +object of a certain kind appears in more than one place in the +containing structure. + + These assumptions refer to a single function; except for the RTL +objects that describe global variables and external functions, and a +few standard objects such as small integer constants, no RTL objects +are common to two functions. + + * Each pseudo-register has only a single `reg' object to represent + it, and therefore only a single machine mode. + + * For any symbolic label, there is only one `symbol_ref' object + referring to it. + + * All `const_int' expressions with equal values are shared. + + * There is only one `pc' expression. + + * There is only one `cc0' expression. + + * There is only one `const_double' expression with value 0 for each + floating point mode. Likewise for values 1 and 2. + + * There is only one `const_vector' expression with value 0 for each + vector mode, be it an integer or a double constant vector. + + * No `label_ref' or `scratch' appears in more than one place in the + RTL structure; in other words, it is safe to do a tree-walk of all + the insns in the function and assume that each time a `label_ref' + or `scratch' is seen it is distinct from all others that are seen. + + * Only one `mem' object is normally created for each static variable + or stack slot, so these objects are frequently shared in all the + places they appear. However, separate but equal objects for these + variables are occasionally made. + + * When a single `asm' statement has multiple output operands, a + distinct `asm_operands' expression is made for each output operand. + However, these all share the vector which contains the sequence of + input operands. This sharing is used later on to test whether two + `asm_operands' expressions come from the same statement, so all + optimizations must carefully preserve the sharing if they copy the + vector at all. + + * No RTL object appears in more than one place in the RTL structure + except as described above. Many passes of the compiler rely on + this by assuming that they can modify RTL objects in place without + unwanted side-effects on other insns. + + * During initial RTL generation, shared structure is freely + introduced. After all the RTL for a function has been generated, + all shared structure is copied by `unshare_all_rtl' in + `emit-rtl.c', after which the above rules are guaranteed to be + followed. + + * During the combiner pass, shared structure within an insn can exist + temporarily. However, the shared structure is copied before the + combiner is finished with the insn. This is done by calling + `copy_rtx_if_shared', which is a subroutine of `unshare_all_rtl'. + + +File: gccint.info, Node: Reading RTL, Prev: Sharing, Up: RTL + +10.22 Reading RTL +================= + +To read an RTL object from a file, call `read_rtx'. It takes one +argument, a stdio stream, and returns a single RTL object. This routine +is defined in `read-rtl.c'. It is not available in the compiler +itself, only the various programs that generate the compiler back end +from the machine description. + + People frequently have the idea of using RTL stored as text in a file +as an interface between a language front end and the bulk of GCC. This +idea is not feasible. + + GCC was designed to use RTL internally only. Correct RTL for a given +program is very dependent on the particular target machine. And the RTL +does not contain all the information about the program. + + The proper way to interface GCC to a new language front end is with +the "tree" data structure, described in the files `tree.h' and +`tree.def'. The documentation for this structure (*note GENERIC::) is +incomplete. + + +File: gccint.info, Node: GENERIC, Next: GIMPLE, Prev: Passes, Up: Top + +11 GENERIC +********** + +The purpose of GENERIC is simply to provide a language-independent way +of representing an entire function in trees. To this end, it was +necessary to add a few new tree codes to the back end, but most +everything was already there. If you can express it with the codes in +`gcc/tree.def', it's GENERIC. + + Early on, there was a great deal of debate about how to think about +statements in a tree IL. In GENERIC, a statement is defined as any +expression whose value, if any, is ignored. A statement will always +have `TREE_SIDE_EFFECTS' set (or it will be discarded), but a +non-statement expression may also have side effects. A `CALL_EXPR', +for instance. + + It would be possible for some local optimizations to work on the +GENERIC form of a function; indeed, the adapted tree inliner works fine +on GENERIC, but the current compiler performs inlining after lowering +to GIMPLE (a restricted form described in the next section). Indeed, +currently the frontends perform this lowering before handing off to +`tree_rest_of_compilation', but this seems inelegant. + +* Menu: + +* Deficiencies:: Topics net yet covered in this document. +* Tree overview:: All about `tree's. +* Types:: Fundamental and aggregate types. +* Declarations:: Type declarations and variables. +* Attributes:: Declaration and type attributes. +* Expressions: Expression trees. Operating on data. +* Statements:: Control flow and related trees. +* Functions:: Function bodies, linkage, and other aspects. +* Language-dependent trees:: Topics and trees specific to language front ends. +* C and C++ Trees:: Trees specific to C and C++. +* Java Trees:: Trees specific to Java. + + +File: gccint.info, Node: Deficiencies, Next: Tree overview, Up: GENERIC + +11.1 Deficiencies +================= + +There are many places in which this document is incomplet and incorrekt. +It is, as of yet, only _preliminary_ documentation. + + +File: gccint.info, Node: Tree overview, Next: Types, Prev: Deficiencies, Up: GENERIC + +11.2 Overview +============= + +The central data structure used by the internal representation is the +`tree'. These nodes, while all of the C type `tree', are of many +varieties. A `tree' is a pointer type, but the object to which it +points may be of a variety of types. From this point forward, we will +refer to trees in ordinary type, rather than in `this font', except +when talking about the actual C type `tree'. + + You can tell what kind of node a particular tree is by using the +`TREE_CODE' macro. Many, many macros take trees as input and return +trees as output. However, most macros require a certain kind of tree +node as input. In other words, there is a type-system for trees, but +it is not reflected in the C type-system. + + For safety, it is useful to configure GCC with `--enable-checking'. +Although this results in a significant performance penalty (since all +tree types are checked at run-time), and is therefore inappropriate in a +release version, it is extremely helpful during the development process. + + Many macros behave as predicates. Many, although not all, of these +predicates end in `_P'. Do not rely on the result type of these macros +being of any particular type. You may, however, rely on the fact that +the type can be compared to `0', so that statements like + if (TEST_P (t) && !TEST_P (y)) + x = 1; + and + int i = (TEST_P (t) != 0); + are legal. Macros that return `int' values now may be changed to +return `tree' values, or other pointers in the future. Even those that +continue to return `int' may return multiple nonzero codes where +previously they returned only zero and one. Therefore, you should not +write code like + if (TEST_P (t) == 1) + as this code is not guaranteed to work correctly in the future. + + You should not take the address of values returned by the macros or +functions described here. In particular, no guarantee is given that the +values are lvalues. + + In general, the names of macros are all in uppercase, while the names +of functions are entirely in lowercase. There are rare exceptions to +this rule. You should assume that any macro or function whose name is +made up entirely of uppercase letters may evaluate its arguments more +than once. You may assume that a macro or function whose name is made +up entirely of lowercase letters will evaluate its arguments only once. + + The `error_mark_node' is a special tree. Its tree code is +`ERROR_MARK', but since there is only ever one node with that code, the +usual practice is to compare the tree against `error_mark_node'. (This +test is just a test for pointer equality.) If an error has occurred +during front-end processing the flag `errorcount' will be set. If the +front end has encountered code it cannot handle, it will issue a +message to the user and set `sorrycount'. When these flags are set, +any macro or function which normally returns a tree of a particular +kind may instead return the `error_mark_node'. Thus, if you intend to +do any processing of erroneous code, you must be prepared to deal with +the `error_mark_node'. + + Occasionally, a particular tree slot (like an operand to an expression, +or a particular field in a declaration) will be referred to as +"reserved for the back end". These slots are used to store RTL when +the tree is converted to RTL for use by the GCC back end. However, if +that process is not taking place (e.g., if the front end is being hooked +up to an intelligent editor), then those slots may be used by the back +end presently in use. + + If you encounter situations that do not match this documentation, such +as tree nodes of types not mentioned here, or macros documented to +return entities of a particular kind that instead return entities of +some different kind, you have found a bug, either in the front end or in +the documentation. Please report these bugs as you would any other bug. + +* Menu: + +* Macros and Functions::Macros and functions that can be used with all trees. +* Identifiers:: The names of things. +* Containers:: Lists and vectors. + + +File: gccint.info, Node: Macros and Functions, Next: Identifiers, Up: Tree overview + +11.2.1 Trees +------------ + +All GENERIC trees have two fields in common. First, `TREE_CHAIN' is a +pointer that can be used as a singly-linked list to other trees. The +other is `TREE_TYPE'. Many trees store the type of an expression or +declaration in this field. + + These are some other functions for handling trees: + +`tree_size' + Return the number of bytes a tree takes. + +`build0' +`build1' +`build2' +`build3' +`build4' +`build5' +`build6' + These functions build a tree and supply values to put in each + parameter. The basic signature is `code, type, [operands]'. + `code' is the `TREE_CODE', and `type' is a tree representing the + `TREE_TYPE'. These are followed by the operands, each of which is + also a tree. + + + +File: gccint.info, Node: Identifiers, Next: Containers, Prev: Macros and Functions, Up: Tree overview + +11.2.2 Identifiers +------------------ + +An `IDENTIFIER_NODE' represents a slightly more general concept that +the standard C or C++ concept of identifier. In particular, an +`IDENTIFIER_NODE' may contain a `$', or other extraordinary characters. + + There are never two distinct `IDENTIFIER_NODE's representing the same +identifier. Therefore, you may use pointer equality to compare +`IDENTIFIER_NODE's, rather than using a routine like `strcmp'. Use +`get_identifier' to obtain the unique `IDENTIFIER_NODE' for a supplied +string. + + You can use the following macros to access identifiers: +`IDENTIFIER_POINTER' + The string represented by the identifier, represented as a + `char*'. This string is always `NUL'-terminated, and contains no + embedded `NUL' characters. + +`IDENTIFIER_LENGTH' + The length of the string returned by `IDENTIFIER_POINTER', not + including the trailing `NUL'. This value of `IDENTIFIER_LENGTH + (x)' is always the same as `strlen (IDENTIFIER_POINTER (x))'. + +`IDENTIFIER_OPNAME_P' + This predicate holds if the identifier represents the name of an + overloaded operator. In this case, you should not depend on the + contents of either the `IDENTIFIER_POINTER' or the + `IDENTIFIER_LENGTH'. + +`IDENTIFIER_TYPENAME_P' + This predicate holds if the identifier represents the name of a + user-defined conversion operator. In this case, the `TREE_TYPE' of + the `IDENTIFIER_NODE' holds the type to which the conversion + operator converts. + + + +File: gccint.info, Node: Containers, Prev: Identifiers, Up: Tree overview + +11.2.3 Containers +----------------- + +Two common container data structures can be represented directly with +tree nodes. A `TREE_LIST' is a singly linked list containing two trees +per node. These are the `TREE_PURPOSE' and `TREE_VALUE' of each node. +(Often, the `TREE_PURPOSE' contains some kind of tag, or additional +information, while the `TREE_VALUE' contains the majority of the +payload. In other cases, the `TREE_PURPOSE' is simply `NULL_TREE', +while in still others both the `TREE_PURPOSE' and `TREE_VALUE' are of +equal stature.) Given one `TREE_LIST' node, the next node is found by +following the `TREE_CHAIN'. If the `TREE_CHAIN' is `NULL_TREE', then +you have reached the end of the list. + + A `TREE_VEC' is a simple vector. The `TREE_VEC_LENGTH' is an integer +(not a tree) giving the number of nodes in the vector. The nodes +themselves are accessed using the `TREE_VEC_ELT' macro, which takes two +arguments. The first is the `TREE_VEC' in question; the second is an +integer indicating which element in the vector is desired. The +elements are indexed from zero. + + +File: gccint.info, Node: Types, Next: Declarations, Prev: Tree overview, Up: GENERIC + +11.3 Types +========== + +All types have corresponding tree nodes. However, you should not assume +that there is exactly one tree node corresponding to each type. There +are often multiple nodes corresponding to the same type. + + For the most part, different kinds of types have different tree codes. +(For example, pointer types use a `POINTER_TYPE' code while arrays use +an `ARRAY_TYPE' code.) However, pointers to member functions use the +`RECORD_TYPE' code. Therefore, when writing a `switch' statement that +depends on the code associated with a particular type, you should take +care to handle pointers to member functions under the `RECORD_TYPE' +case label. + + The following functions and macros deal with cv-qualification of types: +`TYPE_MAIN_VARIANT' + This macro returns the unqualified version of a type. It may be + applied to an unqualified type, but it is not always the identity + function in that case. + + A few other macros and functions are usable with all types: +`TYPE_SIZE' + The number of bits required to represent the type, represented as + an `INTEGER_CST'. For an incomplete type, `TYPE_SIZE' will be + `NULL_TREE'. + +`TYPE_ALIGN' + The alignment of the type, in bits, represented as an `int'. + +`TYPE_NAME' + This macro returns a declaration (in the form of a `TYPE_DECL') for + the type. (Note this macro does _not_ return an + `IDENTIFIER_NODE', as you might expect, given its name!) You can + look at the `DECL_NAME' of the `TYPE_DECL' to obtain the actual + name of the type. The `TYPE_NAME' will be `NULL_TREE' for a type + that is not a built-in type, the result of a typedef, or a named + class type. + +`TYPE_CANONICAL' + This macro returns the "canonical" type for the given type node. + Canonical types are used to improve performance in the C++ and + Objective-C++ front ends by allowing efficient comparison between + two type nodes in `same_type_p': if the `TYPE_CANONICAL' values of + the types are equal, the types are equivalent; otherwise, the types + are not equivalent. The notion of equivalence for canonical types + is the same as the notion of type equivalence in the language + itself. For instance, + + When `TYPE_CANONICAL' is `NULL_TREE', there is no canonical type + for the given type node. In this case, comparison between this + type and any other type requires the compiler to perform a deep, + "structural" comparison to see if the two type nodes have the same + form and properties. + + The canonical type for a node is always the most fundamental type + in the equivalence class of types. For instance, `int' is its own + canonical type. A typedef `I' of `int' will have `int' as its + canonical type. Similarly, `I*' and a typedef `IP' (defined to + `I*') will has `int*' as their canonical type. When building a new + type node, be sure to set `TYPE_CANONICAL' to the appropriate + canonical type. If the new type is a compound type (built from + other types), and any of those other types require structural + equality, use `SET_TYPE_STRUCTURAL_EQUALITY' to ensure that the + new type also requires structural equality. Finally, if for some + reason you cannot guarantee that `TYPE_CANONICAL' will point to + the canonical type, use `SET_TYPE_STRUCTURAL_EQUALITY' to make + sure that the new type-and any type constructed based on + it-requires structural equality. If you suspect that the canonical + type system is miscomparing types, pass `--param + verify-canonical-types=1' to the compiler or configure with + `--enable-checking' to force the compiler to verify its + canonical-type comparisons against the structural comparisons; the + compiler will then print any warnings if the canonical types + miscompare. + +`TYPE_STRUCTURAL_EQUALITY_P' + This predicate holds when the node requires structural equality + checks, e.g., when `TYPE_CANONICAL' is `NULL_TREE'. + +`SET_TYPE_STRUCTURAL_EQUALITY' + This macro states that the type node it is given requires + structural equality checks, e.g., it sets `TYPE_CANONICAL' to + `NULL_TREE'. + +`same_type_p' + This predicate takes two types as input, and holds if they are the + same type. For example, if one type is a `typedef' for the other, + or both are `typedef's for the same type. This predicate also + holds if the two trees given as input are simply copies of one + another; i.e., there is no difference between them at the source + level, but, for whatever reason, a duplicate has been made in the + representation. You should never use `==' (pointer equality) to + compare types; always use `same_type_p' instead. + + Detailed below are the various kinds of types, and the macros that can +be used to access them. Although other kinds of types are used +elsewhere in G++, the types described here are the only ones that you +will encounter while examining the intermediate representation. + +`VOID_TYPE' + Used to represent the `void' type. + +`INTEGER_TYPE' + Used to represent the various integral types, including `char', + `short', `int', `long', and `long long'. This code is not used + for enumeration types, nor for the `bool' type. The + `TYPE_PRECISION' is the number of bits used in the representation, + represented as an `unsigned int'. (Note that in the general case + this is not the same value as `TYPE_SIZE'; suppose that there were + a 24-bit integer type, but that alignment requirements for the ABI + required 32-bit alignment. Then, `TYPE_SIZE' would be an + `INTEGER_CST' for 32, while `TYPE_PRECISION' would be 24.) The + integer type is unsigned if `TYPE_UNSIGNED' holds; otherwise, it + is signed. + + The `TYPE_MIN_VALUE' is an `INTEGER_CST' for the smallest integer + that may be represented by this type. Similarly, the + `TYPE_MAX_VALUE' is an `INTEGER_CST' for the largest integer that + may be represented by this type. + +`REAL_TYPE' + Used to represent the `float', `double', and `long double' types. + The number of bits in the floating-point representation is given + by `TYPE_PRECISION', as in the `INTEGER_TYPE' case. + +`FIXED_POINT_TYPE' + Used to represent the `short _Fract', `_Fract', `long _Fract', + `long long _Fract', `short _Accum', `_Accum', `long _Accum', and + `long long _Accum' types. The number of bits in the fixed-point + representation is given by `TYPE_PRECISION', as in the + `INTEGER_TYPE' case. There may be padding bits, fractional bits + and integral bits. The number of fractional bits is given by + `TYPE_FBIT', and the number of integral bits is given by + `TYPE_IBIT'. The fixed-point type is unsigned if `TYPE_UNSIGNED' + holds; otherwise, it is signed. The fixed-point type is + saturating if `TYPE_SATURATING' holds; otherwise, it is not + saturating. + +`COMPLEX_TYPE' + Used to represent GCC built-in `__complex__' data types. The + `TREE_TYPE' is the type of the real and imaginary parts. + +`ENUMERAL_TYPE' + Used to represent an enumeration type. The `TYPE_PRECISION' gives + (as an `int'), the number of bits used to represent the type. If + there are no negative enumeration constants, `TYPE_UNSIGNED' will + hold. The minimum and maximum enumeration constants may be + obtained with `TYPE_MIN_VALUE' and `TYPE_MAX_VALUE', respectively; + each of these macros returns an `INTEGER_CST'. + + The actual enumeration constants themselves may be obtained by + looking at the `TYPE_VALUES'. This macro will return a + `TREE_LIST', containing the constants. The `TREE_PURPOSE' of each + node will be an `IDENTIFIER_NODE' giving the name of the constant; + the `TREE_VALUE' will be an `INTEGER_CST' giving the value + assigned to that constant. These constants will appear in the + order in which they were declared. The `TREE_TYPE' of each of + these constants will be the type of enumeration type itself. + +`BOOLEAN_TYPE' + Used to represent the `bool' type. + +`POINTER_TYPE' + Used to represent pointer types, and pointer to data member types. + The `TREE_TYPE' gives the type to which this type points. + +`REFERENCE_TYPE' + Used to represent reference types. The `TREE_TYPE' gives the type + to which this type refers. + +`FUNCTION_TYPE' + Used to represent the type of non-member functions and of static + member functions. The `TREE_TYPE' gives the return type of the + function. The `TYPE_ARG_TYPES' are a `TREE_LIST' of the argument + types. The `TREE_VALUE' of each node in this list is the type of + the corresponding argument; the `TREE_PURPOSE' is an expression + for the default argument value, if any. If the last node in the + list is `void_list_node' (a `TREE_LIST' node whose `TREE_VALUE' is + the `void_type_node'), then functions of this type do not take + variable arguments. Otherwise, they do take a variable number of + arguments. + + Note that in C (but not in C++) a function declared like `void f()' + is an unprototyped function taking a variable number of arguments; + the `TYPE_ARG_TYPES' of such a function will be `NULL'. + +`METHOD_TYPE' + Used to represent the type of a non-static member function. Like a + `FUNCTION_TYPE', the return type is given by the `TREE_TYPE'. The + type of `*this', i.e., the class of which functions of this type + are a member, is given by the `TYPE_METHOD_BASETYPE'. The + `TYPE_ARG_TYPES' is the parameter list, as for a `FUNCTION_TYPE', + and includes the `this' argument. + +`ARRAY_TYPE' + Used to represent array types. The `TREE_TYPE' gives the type of + the elements in the array. If the array-bound is present in the + type, the `TYPE_DOMAIN' is an `INTEGER_TYPE' whose + `TYPE_MIN_VALUE' and `TYPE_MAX_VALUE' will be the lower and upper + bounds of the array, respectively. The `TYPE_MIN_VALUE' will + always be an `INTEGER_CST' for zero, while the `TYPE_MAX_VALUE' + will be one less than the number of elements in the array, i.e., + the highest value which may be used to index an element in the + array. + +`RECORD_TYPE' + Used to represent `struct' and `class' types, as well as pointers + to member functions and similar constructs in other languages. + `TYPE_FIELDS' contains the items contained in this type, each of + which can be a `FIELD_DECL', `VAR_DECL', `CONST_DECL', or + `TYPE_DECL'. You may not make any assumptions about the ordering + of the fields in the type or whether one or more of them overlap. + +`UNION_TYPE' + Used to represent `union' types. Similar to `RECORD_TYPE' except + that all `FIELD_DECL' nodes in `TYPE_FIELD' start at bit position + zero. + +`QUAL_UNION_TYPE' + Used to represent part of a variant record in Ada. Similar to + `UNION_TYPE' except that each `FIELD_DECL' has a `DECL_QUALIFIER' + field, which contains a boolean expression that indicates whether + the field is present in the object. The type will only have one + field, so each field's `DECL_QUALIFIER' is only evaluated if none + of the expressions in the previous fields in `TYPE_FIELDS' are + nonzero. Normally these expressions will reference a field in the + outer object using a `PLACEHOLDER_EXPR'. + +`LANG_TYPE' + This node is used to represent a language-specific type. The front + end must handle it. + +`OFFSET_TYPE' + This node is used to represent a pointer-to-data member. For a + data member `X::m' the `TYPE_OFFSET_BASETYPE' is `X' and the + `TREE_TYPE' is the type of `m'. + + + There are variables whose values represent some of the basic types. +These include: +`void_type_node' + A node for `void'. + +`integer_type_node' + A node for `int'. + +`unsigned_type_node.' + A node for `unsigned int'. + +`char_type_node.' + A node for `char'. + It may sometimes be useful to compare one of these variables with a +type in hand, using `same_type_p'. + + +File: gccint.info, Node: Declarations, Next: Attributes, Prev: Types, Up: GENERIC + +11.4 Declarations +================= + +This section covers the various kinds of declarations that appear in the +internal representation, except for declarations of functions +(represented by `FUNCTION_DECL' nodes), which are described in *note +Functions::. + +* Menu: + +* Working with declarations:: Macros and functions that work on +declarations. +* Internal structure:: How declaration nodes are represented. + + +File: gccint.info, Node: Working with declarations, Next: Internal structure, Up: Declarations + +11.4.1 Working with declarations +-------------------------------- + +Some macros can be used with any kind of declaration. These include: +`DECL_NAME' + This macro returns an `IDENTIFIER_NODE' giving the name of the + entity. + +`TREE_TYPE' + This macro returns the type of the entity declared. + +`EXPR_FILENAME' + This macro returns the name of the file in which the entity was + declared, as a `char*'. For an entity declared implicitly by the + compiler (like `__builtin_memcpy'), this will be the string + `"<internal>"'. + +`EXPR_LINENO' + This macro returns the line number at which the entity was + declared, as an `int'. + +`DECL_ARTIFICIAL' + This predicate holds if the declaration was implicitly generated + by the compiler. For example, this predicate will hold of an + implicitly declared member function, or of the `TYPE_DECL' + implicitly generated for a class type. Recall that in C++ code + like: + struct S {}; + is roughly equivalent to C code like: + struct S {}; + typedef struct S S; + The implicitly generated `typedef' declaration is represented by a + `TYPE_DECL' for which `DECL_ARTIFICIAL' holds. + + + The various kinds of declarations include: +`LABEL_DECL' + These nodes are used to represent labels in function bodies. For + more information, see *note Functions::. These nodes only appear + in block scopes. + +`CONST_DECL' + These nodes are used to represent enumeration constants. The + value of the constant is given by `DECL_INITIAL' which will be an + `INTEGER_CST' with the same type as the `TREE_TYPE' of the + `CONST_DECL', i.e., an `ENUMERAL_TYPE'. + +`RESULT_DECL' + These nodes represent the value returned by a function. When a + value is assigned to a `RESULT_DECL', that indicates that the + value should be returned, via bitwise copy, by the function. You + can use `DECL_SIZE' and `DECL_ALIGN' on a `RESULT_DECL', just as + with a `VAR_DECL'. + +`TYPE_DECL' + These nodes represent `typedef' declarations. The `TREE_TYPE' is + the type declared to have the name given by `DECL_NAME'. In some + cases, there is no associated name. + +`VAR_DECL' + These nodes represent variables with namespace or block scope, as + well as static data members. The `DECL_SIZE' and `DECL_ALIGN' are + analogous to `TYPE_SIZE' and `TYPE_ALIGN'. For a declaration, you + should always use the `DECL_SIZE' and `DECL_ALIGN' rather than the + `TYPE_SIZE' and `TYPE_ALIGN' given by the `TREE_TYPE', since + special attributes may have been applied to the variable to give + it a particular size and alignment. You may use the predicates + `DECL_THIS_STATIC' or `DECL_THIS_EXTERN' to test whether the + storage class specifiers `static' or `extern' were used to declare + a variable. + + If this variable is initialized (but does not require a + constructor), the `DECL_INITIAL' will be an expression for the + initializer. The initializer should be evaluated, and a bitwise + copy into the variable performed. If the `DECL_INITIAL' is the + `error_mark_node', there is an initializer, but it is given by an + explicit statement later in the code; no bitwise copy is required. + + GCC provides an extension that allows either automatic variables, + or global variables, to be placed in particular registers. This + extension is being used for a particular `VAR_DECL' if + `DECL_REGISTER' holds for the `VAR_DECL', and if + `DECL_ASSEMBLER_NAME' is not equal to `DECL_NAME'. In that case, + `DECL_ASSEMBLER_NAME' is the name of the register into which the + variable will be placed. + +`PARM_DECL' + Used to represent a parameter to a function. Treat these nodes + similarly to `VAR_DECL' nodes. These nodes only appear in the + `DECL_ARGUMENTS' for a `FUNCTION_DECL'. + + The `DECL_ARG_TYPE' for a `PARM_DECL' is the type that will + actually be used when a value is passed to this function. It may + be a wider type than the `TREE_TYPE' of the parameter; for + example, the ordinary type might be `short' while the + `DECL_ARG_TYPE' is `int'. + +`DEBUG_EXPR_DECL' + Used to represent an anonymous debug-information temporary created + to hold an expression as it is optimized away, so that its value + can be referenced in debug bind statements. + +`FIELD_DECL' + These nodes represent non-static data members. The `DECL_SIZE' and + `DECL_ALIGN' behave as for `VAR_DECL' nodes. The position of the + field within the parent record is specified by a combination of + three attributes. `DECL_FIELD_OFFSET' is the position, counting + in bytes, of the `DECL_OFFSET_ALIGN'-bit sized word containing the + bit of the field closest to the beginning of the structure. + `DECL_FIELD_BIT_OFFSET' is the bit offset of the first bit of the + field within this word; this may be nonzero even for fields that + are not bit-fields, since `DECL_OFFSET_ALIGN' may be greater than + the natural alignment of the field's type. + + If `DECL_C_BIT_FIELD' holds, this field is a bit-field. In a + bit-field, `DECL_BIT_FIELD_TYPE' also contains the type that was + originally specified for it, while DECL_TYPE may be a modified + type with lesser precision, according to the size of the bit field. + +`NAMESPACE_DECL' + Namespaces provide a name hierarchy for other declarations. They + appear in the `DECL_CONTEXT' of other `_DECL' nodes. + + + +File: gccint.info, Node: Internal structure, Prev: Working with declarations, Up: Declarations + +11.4.2 Internal structure +------------------------- + +`DECL' nodes are represented internally as a hierarchy of structures. + +* Menu: + +* Current structure hierarchy:: The current DECL node structure +hierarchy. +* Adding new DECL node types:: How to add a new DECL node to a +frontend. + + +File: gccint.info, Node: Current structure hierarchy, Next: Adding new DECL node types, Up: Internal structure + +11.4.2.1 Current structure hierarchy +.................................... + +`struct tree_decl_minimal' + This is the minimal structure to inherit from in order for common + `DECL' macros to work. The fields it contains are a unique ID, + source location, context, and name. + +`struct tree_decl_common' + This structure inherits from `struct tree_decl_minimal'. It + contains fields that most `DECL' nodes need, such as a field to + store alignment, machine mode, size, and attributes. + +`struct tree_field_decl' + This structure inherits from `struct tree_decl_common'. It is + used to represent `FIELD_DECL'. + +`struct tree_label_decl' + This structure inherits from `struct tree_decl_common'. It is + used to represent `LABEL_DECL'. + +`struct tree_translation_unit_decl' + This structure inherits from `struct tree_decl_common'. It is + used to represent `TRANSLATION_UNIT_DECL'. + +`struct tree_decl_with_rtl' + This structure inherits from `struct tree_decl_common'. It + contains a field to store the low-level RTL associated with a + `DECL' node. + +`struct tree_result_decl' + This structure inherits from `struct tree_decl_with_rtl'. It is + used to represent `RESULT_DECL'. + +`struct tree_const_decl' + This structure inherits from `struct tree_decl_with_rtl'. It is + used to represent `CONST_DECL'. + +`struct tree_parm_decl' + This structure inherits from `struct tree_decl_with_rtl'. It is + used to represent `PARM_DECL'. + +`struct tree_decl_with_vis' + This structure inherits from `struct tree_decl_with_rtl'. It + contains fields necessary to store visibility information, as well + as a section name and assembler name. + +`struct tree_var_decl' + This structure inherits from `struct tree_decl_with_vis'. It is + used to represent `VAR_DECL'. + +`struct tree_function_decl' + This structure inherits from `struct tree_decl_with_vis'. It is + used to represent `FUNCTION_DECL'. + + + +File: gccint.info, Node: Adding new DECL node types, Prev: Current structure hierarchy, Up: Internal structure + +11.4.2.2 Adding new DECL node types +................................... + +Adding a new `DECL' tree consists of the following steps + +Add a new tree code for the `DECL' node + For language specific `DECL' nodes, there is a `.def' file in each + frontend directory where the tree code should be added. For + `DECL' nodes that are part of the middle-end, the code should be + added to `tree.def'. + +Create a new structure type for the `DECL' node + These structures should inherit from one of the existing + structures in the language hierarchy by using that structure as + the first member. + + struct tree_foo_decl + { + struct tree_decl_with_vis common; + } + + Would create a structure name `tree_foo_decl' that inherits from + `struct tree_decl_with_vis'. + + For language specific `DECL' nodes, this new structure type should + go in the appropriate `.h' file. For `DECL' nodes that are part + of the middle-end, the structure type should go in `tree.h'. + +Add a member to the tree structure enumerator for the node + For garbage collection and dynamic checking purposes, each `DECL' + node structure type is required to have a unique enumerator value + specified with it. For language specific `DECL' nodes, this new + enumerator value should go in the appropriate `.def' file. For + `DECL' nodes that are part of the middle-end, the enumerator + values are specified in `treestruct.def'. + +Update `union tree_node' + In order to make your new structure type usable, it must be added + to `union tree_node'. For language specific `DECL' nodes, a new + entry should be added to the appropriate `.h' file of the form + struct tree_foo_decl GTY ((tag ("TS_VAR_DECL"))) foo_decl; + For `DECL' nodes that are part of the middle-end, the additional + member goes directly into `union tree_node' in `tree.h'. + +Update dynamic checking info + In order to be able to check whether accessing a named portion of + `union tree_node' is legal, and whether a certain `DECL' node + contains one of the enumerated `DECL' node structures in the + hierarchy, a simple lookup table is used. This lookup table needs + to be kept up to date with the tree structure hierarchy, or else + checking and containment macros will fail inappropriately. + + For language specific `DECL' nodes, their is an `init_ts' function + in an appropriate `.c' file, which initializes the lookup table. + Code setting up the table for new `DECL' nodes should be added + there. For each `DECL' tree code and enumerator value + representing a member of the inheritance hierarchy, the table + should contain 1 if that tree code inherits (directly or + indirectly) from that member. Thus, a `FOO_DECL' node derived + from `struct decl_with_rtl', and enumerator value `TS_FOO_DECL', + would be set up as follows + tree_contains_struct[FOO_DECL][TS_FOO_DECL] = 1; + tree_contains_struct[FOO_DECL][TS_DECL_WRTL] = 1; + tree_contains_struct[FOO_DECL][TS_DECL_COMMON] = 1; + tree_contains_struct[FOO_DECL][TS_DECL_MINIMAL] = 1; + + For `DECL' nodes that are part of the middle-end, the setup code + goes into `tree.c'. + +Add macros to access any new fields and flags + Each added field or flag should have a macro that is used to access + it, that performs appropriate checking to ensure only the right + type of `DECL' nodes access the field. + + These macros generally take the following form + #define FOO_DECL_FIELDNAME(NODE) FOO_DECL_CHECK(NODE)->foo_decl.fieldname + However, if the structure is simply a base class for further + structures, something like the following should be used + #define BASE_STRUCT_CHECK(T) CONTAINS_STRUCT_CHECK(T, TS_BASE_STRUCT) + #define BASE_STRUCT_FIELDNAME(NODE) \ + (BASE_STRUCT_CHECK(NODE)->base_struct.fieldname + + + +File: gccint.info, Node: Attributes, Next: Expression trees, Prev: Declarations, Up: GENERIC + +11.5 Attributes in trees +======================== + +Attributes, as specified using the `__attribute__' keyword, are +represented internally as a `TREE_LIST'. The `TREE_PURPOSE' is the +name of the attribute, as an `IDENTIFIER_NODE'. The `TREE_VALUE' is a +`TREE_LIST' of the arguments of the attribute, if any, or `NULL_TREE' +if there are no arguments; the arguments are stored as the `TREE_VALUE' +of successive entries in the list, and may be identifiers or +expressions. The `TREE_CHAIN' of the attribute is the next attribute +in a list of attributes applying to the same declaration or type, or +`NULL_TREE' if there are no further attributes in the list. + + Attributes may be attached to declarations and to types; these +attributes may be accessed with the following macros. All attributes +are stored in this way, and many also cause other changes to the +declaration or type or to other internal compiler data structures. + + -- Tree Macro: tree DECL_ATTRIBUTES (tree DECL) + This macro returns the attributes on the declaration DECL. + + -- Tree Macro: tree TYPE_ATTRIBUTES (tree TYPE) + This macro returns the attributes on the type TYPE. + + +File: gccint.info, Node: Expression trees, Next: Statements, Prev: Attributes, Up: GENERIC + +11.6 Expressions +================ + +The internal representation for expressions is for the most part quite +straightforward. However, there are a few facts that one must bear in +mind. In particular, the expression "tree" is actually a directed +acyclic graph. (For example there may be many references to the integer +constant zero throughout the source program; many of these will be +represented by the same expression node.) You should not rely on +certain kinds of node being shared, nor should you rely on certain +kinds of nodes being unshared. + + The following macros can be used with all expression nodes: + +`TREE_TYPE' + Returns the type of the expression. This value may not be + precisely the same type that would be given the expression in the + original program. + + In what follows, some nodes that one might expect to always have type +`bool' are documented to have either integral or boolean type. At some +point in the future, the C front end may also make use of this same +intermediate representation, and at this point these nodes will +certainly have integral type. The previous sentence is not meant to +imply that the C++ front end does not or will not give these nodes +integral type. + + Below, we list the various kinds of expression nodes. Except where +noted otherwise, the operands to an expression are accessed using the +`TREE_OPERAND' macro. For example, to access the first operand to a +binary plus expression `expr', use: + + TREE_OPERAND (expr, 0) + As this example indicates, the operands are zero-indexed. + +* Menu: + +* Constants: Constant expressions. +* Storage References:: +* Unary and Binary Expressions:: +* Vectors:: + + +File: gccint.info, Node: Constant expressions, Next: Storage References, Up: Expression trees + +11.6.1 Constant expressions +--------------------------- + +The table below begins with constants, moves on to unary expressions, +then proceeds to binary expressions, and concludes with various other +kinds of expressions: + +`INTEGER_CST' + These nodes represent integer constants. Note that the type of + these constants is obtained with `TREE_TYPE'; they are not always + of type `int'. In particular, `char' constants are represented + with `INTEGER_CST' nodes. The value of the integer constant `e' is + given by + ((TREE_INT_CST_HIGH (e) << HOST_BITS_PER_WIDE_INT) + + TREE_INST_CST_LOW (e)) + HOST_BITS_PER_WIDE_INT is at least thirty-two on all platforms. + Both `TREE_INT_CST_HIGH' and `TREE_INT_CST_LOW' return a + `HOST_WIDE_INT'. The value of an `INTEGER_CST' is interpreted as + a signed or unsigned quantity depending on the type of the + constant. In general, the expression given above will overflow, + so it should not be used to calculate the value of the constant. + + The variable `integer_zero_node' is an integer constant with value + zero. Similarly, `integer_one_node' is an integer constant with + value one. The `size_zero_node' and `size_one_node' variables are + analogous, but have type `size_t' rather than `int'. + + The function `tree_int_cst_lt' is a predicate which holds if its + first argument is less than its second. Both constants are + assumed to have the same signedness (i.e., either both should be + signed or both should be unsigned.) The full width of the + constant is used when doing the comparison; the usual rules about + promotions and conversions are ignored. Similarly, + `tree_int_cst_equal' holds if the two constants are equal. The + `tree_int_cst_sgn' function returns the sign of a constant. The + value is `1', `0', or `-1' according on whether the constant is + greater than, equal to, or less than zero. Again, the signedness + of the constant's type is taken into account; an unsigned constant + is never less than zero, no matter what its bit-pattern. + +`REAL_CST' + FIXME: Talk about how to obtain representations of this constant, + do comparisons, and so forth. + +`FIXED_CST' + These nodes represent fixed-point constants. The type of these + constants is obtained with `TREE_TYPE'. `TREE_FIXED_CST_PTR' + points to a `struct fixed_value'; `TREE_FIXED_CST' returns the + structure itself. `struct fixed_value' contains `data' with the + size of two `HOST_BITS_PER_WIDE_INT' and `mode' as the associated + fixed-point machine mode for `data'. + +`COMPLEX_CST' + These nodes are used to represent complex number constants, that + is a `__complex__' whose parts are constant nodes. The + `TREE_REALPART' and `TREE_IMAGPART' return the real and the + imaginary parts respectively. + +`VECTOR_CST' + These nodes are used to represent vector constants, whose parts are + constant nodes. Each individual constant node is either an + integer or a double constant node. The first operand is a + `TREE_LIST' of the constant nodes and is accessed through + `TREE_VECTOR_CST_ELTS'. + +`STRING_CST' + These nodes represent string-constants. The `TREE_STRING_LENGTH' + returns the length of the string, as an `int'. The + `TREE_STRING_POINTER' is a `char*' containing the string itself. + The string may not be `NUL'-terminated, and it may contain + embedded `NUL' characters. Therefore, the `TREE_STRING_LENGTH' + includes the trailing `NUL' if it is present. + + For wide string constants, the `TREE_STRING_LENGTH' is the number + of bytes in the string, and the `TREE_STRING_POINTER' points to an + array of the bytes of the string, as represented on the target + system (that is, as integers in the target endianness). Wide and + non-wide string constants are distinguished only by the `TREE_TYPE' + of the `STRING_CST'. + + FIXME: The formats of string constants are not well-defined when + the target system bytes are not the same width as host system + bytes. + + + +File: gccint.info, Node: Storage References, Next: Unary and Binary Expressions, Prev: Constant expressions, Up: Expression trees + +11.6.2 References to storage +---------------------------- + +`ARRAY_REF' + These nodes represent array accesses. The first operand is the + array; the second is the index. To calculate the address of the + memory accessed, you must scale the index by the size of the type + of the array elements. The type of these expressions must be the + type of a component of the array. The third and fourth operands + are used after gimplification to represent the lower bound and + component size but should not be used directly; call + `array_ref_low_bound' and `array_ref_element_size' instead. + +`ARRAY_RANGE_REF' + These nodes represent access to a range (or "slice") of an array. + The operands are the same as that for `ARRAY_REF' and have the same + meanings. The type of these expressions must be an array whose + component type is the same as that of the first operand. The + range of that array type determines the amount of data these + expressions access. + +`TARGET_MEM_REF' + These nodes represent memory accesses whose address directly map to + an addressing mode of the target architecture. The first argument + is `TMR_SYMBOL' and must be a `VAR_DECL' of an object with a fixed + address. The second argument is `TMR_BASE' and the third one is + `TMR_INDEX'. The fourth argument is `TMR_STEP' and must be an + `INTEGER_CST'. The fifth argument is `TMR_OFFSET' and must be an + `INTEGER_CST'. Any of the arguments may be NULL if the + appropriate component does not appear in the address. Address of + the `TARGET_MEM_REF' is determined in the following way. + + &TMR_SYMBOL + TMR_BASE + TMR_INDEX * TMR_STEP + TMR_OFFSET + + The sixth argument is the reference to the original memory access, + which is preserved for the purposes of the RTL alias analysis. + The seventh argument is a tag representing the results of tree + level alias analysis. + +`ADDR_EXPR' + These nodes are used to represent the address of an object. (These + expressions will always have pointer or reference type.) The + operand may be another expression, or it may be a declaration. + + As an extension, GCC allows users to take the address of a label. + In this case, the operand of the `ADDR_EXPR' will be a + `LABEL_DECL'. The type of such an expression is `void*'. + + If the object addressed is not an lvalue, a temporary is created, + and the address of the temporary is used. + +`INDIRECT_REF' + These nodes are used to represent the object pointed to by a + pointer. The operand is the pointer being dereferenced; it will + always have pointer or reference type. + +`MEM_REF' + These nodes are used to represent the object pointed to by a + pointer offset by a constant. The first operand is the pointer + being dereferenced; it will always have pointer or reference type. + The second operand is a pointer constant. Its type is specifying + the type to be used for type-based alias analysis. + +`COMPONENT_REF' + These nodes represent non-static data member accesses. The first + operand is the object (rather than a pointer to it); the second + operand is the `FIELD_DECL' for the data member. The third + operand represents the byte offset of the field, but should not be + used directly; call `component_ref_field_offset' instead. + + + +File: gccint.info, Node: Unary and Binary Expressions, Next: Vectors, Prev: Storage References, Up: Expression trees + +11.6.3 Unary and Binary Expressions +----------------------------------- + +`NEGATE_EXPR' + These nodes represent unary negation of the single operand, for + both integer and floating-point types. The type of negation can be + determined by looking at the type of the expression. + + The behavior of this operation on signed arithmetic overflow is + controlled by the `flag_wrapv' and `flag_trapv' variables. + +`ABS_EXPR' + These nodes represent the absolute value of the single operand, for + both integer and floating-point types. This is typically used to + implement the `abs', `labs' and `llabs' builtins for integer + types, and the `fabs', `fabsf' and `fabsl' builtins for floating + point types. The type of abs operation can be determined by + looking at the type of the expression. + + This node is not used for complex types. To represent the modulus + or complex abs of a complex value, use the `BUILT_IN_CABS', + `BUILT_IN_CABSF' or `BUILT_IN_CABSL' builtins, as used to + implement the C99 `cabs', `cabsf' and `cabsl' built-in functions. + +`BIT_NOT_EXPR' + These nodes represent bitwise complement, and will always have + integral type. The only operand is the value to be complemented. + +`TRUTH_NOT_EXPR' + These nodes represent logical negation, and will always have + integral (or boolean) type. The operand is the value being + negated. The type of the operand and that of the result are + always of `BOOLEAN_TYPE' or `INTEGER_TYPE'. + +`PREDECREMENT_EXPR' +`PREINCREMENT_EXPR' +`POSTDECREMENT_EXPR' +`POSTINCREMENT_EXPR' + These nodes represent increment and decrement expressions. The + value of the single operand is computed, and the operand + incremented or decremented. In the case of `PREDECREMENT_EXPR' and + `PREINCREMENT_EXPR', the value of the expression is the value + resulting after the increment or decrement; in the case of + `POSTDECREMENT_EXPR' and `POSTINCREMENT_EXPR' is the value before + the increment or decrement occurs. The type of the operand, like + that of the result, will be either integral, boolean, or + floating-point. + +`FIX_TRUNC_EXPR' + These nodes represent conversion of a floating-point value to an + integer. The single operand will have a floating-point type, while + the complete expression will have an integral (or boolean) type. + The operand is rounded towards zero. + +`FLOAT_EXPR' + These nodes represent conversion of an integral (or boolean) value + to a floating-point value. The single operand will have integral + type, while the complete expression will have a floating-point + type. + + FIXME: How is the operand supposed to be rounded? Is this + dependent on `-mieee'? + +`COMPLEX_EXPR' + These nodes are used to represent complex numbers constructed from + two expressions of the same (integer or real) type. The first + operand is the real part and the second operand is the imaginary + part. + +`CONJ_EXPR' + These nodes represent the conjugate of their operand. + +`REALPART_EXPR' +`IMAGPART_EXPR' + These nodes represent respectively the real and the imaginary parts + of complex numbers (their sole argument). + +`NON_LVALUE_EXPR' + These nodes indicate that their one and only operand is not an + lvalue. A back end can treat these identically to the single + operand. + +`NOP_EXPR' + These nodes are used to represent conversions that do not require + any code-generation. For example, conversion of a `char*' to an + `int*' does not require any code be generated; such a conversion is + represented by a `NOP_EXPR'. The single operand is the expression + to be converted. The conversion from a pointer to a reference is + also represented with a `NOP_EXPR'. + +`CONVERT_EXPR' + These nodes are similar to `NOP_EXPR's, but are used in those + situations where code may need to be generated. For example, if an + `int*' is converted to an `int' code may need to be generated on + some platforms. These nodes are never used for C++-specific + conversions, like conversions between pointers to different + classes in an inheritance hierarchy. Any adjustments that need to + be made in such cases are always indicated explicitly. Similarly, + a user-defined conversion is never represented by a + `CONVERT_EXPR'; instead, the function calls are made explicit. + +`FIXED_CONVERT_EXPR' + These nodes are used to represent conversions that involve + fixed-point values. For example, from a fixed-point value to + another fixed-point value, from an integer to a fixed-point value, + from a fixed-point value to an integer, from a floating-point + value to a fixed-point value, or from a fixed-point value to a + floating-point value. + +`LSHIFT_EXPR' +`RSHIFT_EXPR' + These nodes represent left and right shifts, respectively. The + first operand is the value to shift; it will always be of integral + type. The second operand is an expression for the number of bits + by which to shift. Right shift should be treated as arithmetic, + i.e., the high-order bits should be zero-filled when the + expression has unsigned type and filled with the sign bit when the + expression has signed type. Note that the result is undefined if + the second operand is larger than or equal to the first operand's + type size. + +`BIT_IOR_EXPR' +`BIT_XOR_EXPR' +`BIT_AND_EXPR' + These nodes represent bitwise inclusive or, bitwise exclusive or, + and bitwise and, respectively. Both operands will always have + integral type. + +`TRUTH_ANDIF_EXPR' +`TRUTH_ORIF_EXPR' + These nodes represent logical "and" and logical "or", respectively. + These operators are not strict; i.e., the second operand is + evaluated only if the value of the expression is not determined by + evaluation of the first operand. The type of the operands and + that of the result are always of `BOOLEAN_TYPE' or `INTEGER_TYPE'. + +`TRUTH_AND_EXPR' +`TRUTH_OR_EXPR' +`TRUTH_XOR_EXPR' + These nodes represent logical and, logical or, and logical + exclusive or. They are strict; both arguments are always + evaluated. There are no corresponding operators in C or C++, but + the front end will sometimes generate these expressions anyhow, if + it can tell that strictness does not matter. The type of the + operands and that of the result are always of `BOOLEAN_TYPE' or + `INTEGER_TYPE'. + +`POINTER_PLUS_EXPR' + This node represents pointer arithmetic. The first operand is + always a pointer/reference type. The second operand is always an + unsigned integer type compatible with sizetype. This is the only + binary arithmetic operand that can operate on pointer types. + +`PLUS_EXPR' +`MINUS_EXPR' +`MULT_EXPR' + These nodes represent various binary arithmetic operations. + Respectively, these operations are addition, subtraction (of the + second operand from the first) and multiplication. Their operands + may have either integral or floating type, but there will never be + case in which one operand is of floating type and the other is of + integral type. + + The behavior of these operations on signed arithmetic overflow is + controlled by the `flag_wrapv' and `flag_trapv' variables. + +`RDIV_EXPR' + This node represents a floating point division operation. + +`TRUNC_DIV_EXPR' +`FLOOR_DIV_EXPR' +`CEIL_DIV_EXPR' +`ROUND_DIV_EXPR' + These nodes represent integer division operations that return an + integer result. `TRUNC_DIV_EXPR' rounds towards zero, + `FLOOR_DIV_EXPR' rounds towards negative infinity, `CEIL_DIV_EXPR' + rounds towards positive infinity and `ROUND_DIV_EXPR' rounds to + the closest integer. Integer division in C and C++ is truncating, + i.e. `TRUNC_DIV_EXPR'. + + The behavior of these operations on signed arithmetic overflow, + when dividing the minimum signed integer by minus one, is + controlled by the `flag_wrapv' and `flag_trapv' variables. + +`TRUNC_MOD_EXPR' +`FLOOR_MOD_EXPR' +`CEIL_MOD_EXPR' +`ROUND_MOD_EXPR' + These nodes represent the integer remainder or modulus operation. + The integer modulus of two operands `a' and `b' is defined as `a - + (a/b)*b' where the division calculated using the corresponding + division operator. Hence for `TRUNC_MOD_EXPR' this definition + assumes division using truncation towards zero, i.e. + `TRUNC_DIV_EXPR'. Integer remainder in C and C++ uses truncating + division, i.e. `TRUNC_MOD_EXPR'. + +`EXACT_DIV_EXPR' + The `EXACT_DIV_EXPR' code is used to represent integer divisions + where the numerator is known to be an exact multiple of the + denominator. This allows the backend to choose between the faster + of `TRUNC_DIV_EXPR', `CEIL_DIV_EXPR' and `FLOOR_DIV_EXPR' for the + current target. + +`LT_EXPR' +`LE_EXPR' +`GT_EXPR' +`GE_EXPR' +`EQ_EXPR' +`NE_EXPR' + These nodes represent the less than, less than or equal to, greater + than, greater than or equal to, equal, and not equal comparison + operators. The first and second operand with either be both of + integral type or both of floating type. The result type of these + expressions will always be of integral or boolean type. These + operations return the result type's zero value for false, and the + result type's one value for true. + + For floating point comparisons, if we honor IEEE NaNs and either + operand is NaN, then `NE_EXPR' always returns true and the + remaining operators always return false. On some targets, + comparisons against an IEEE NaN, other than equality and + inequality, may generate a floating point exception. + +`ORDERED_EXPR' +`UNORDERED_EXPR' + These nodes represent non-trapping ordered and unordered comparison + operators. These operations take two floating point operands and + determine whether they are ordered or unordered relative to each + other. If either operand is an IEEE NaN, their comparison is + defined to be unordered, otherwise the comparison is defined to be + ordered. The result type of these expressions will always be of + integral or boolean type. These operations return the result + type's zero value for false, and the result type's one value for + true. + +`UNLT_EXPR' +`UNLE_EXPR' +`UNGT_EXPR' +`UNGE_EXPR' +`UNEQ_EXPR' +`LTGT_EXPR' + These nodes represent the unordered comparison operators. These + operations take two floating point operands and determine whether + the operands are unordered or are less than, less than or equal to, + greater than, greater than or equal to, or equal respectively. For + example, `UNLT_EXPR' returns true if either operand is an IEEE NaN + or the first operand is less than the second. With the possible + exception of `LTGT_EXPR', all of these operations are guaranteed + not to generate a floating point exception. The result type of + these expressions will always be of integral or boolean type. + These operations return the result type's zero value for false, + and the result type's one value for true. + +`MODIFY_EXPR' + These nodes represent assignment. The left-hand side is the first + operand; the right-hand side is the second operand. The left-hand + side will be a `VAR_DECL', `INDIRECT_REF', `COMPONENT_REF', or + other lvalue. + + These nodes are used to represent not only assignment with `=' but + also compound assignments (like `+='), by reduction to `=' + assignment. In other words, the representation for `i += 3' looks + just like that for `i = i + 3'. + +`INIT_EXPR' + These nodes are just like `MODIFY_EXPR', but are used only when a + variable is initialized, rather than assigned to subsequently. + This means that we can assume that the target of the + initialization is not used in computing its own value; any + reference to the lhs in computing the rhs is undefined. + +`COMPOUND_EXPR' + These nodes represent comma-expressions. The first operand is an + expression whose value is computed and thrown away prior to the + evaluation of the second operand. The value of the entire + expression is the value of the second operand. + +`COND_EXPR' + These nodes represent `?:' expressions. The first operand is of + boolean or integral type. If it evaluates to a nonzero value, the + second operand should be evaluated, and returned as the value of + the expression. Otherwise, the third operand is evaluated, and + returned as the value of the expression. + + The second operand must have the same type as the entire + expression, unless it unconditionally throws an exception or calls + a noreturn function, in which case it should have void type. The + same constraints apply to the third operand. This allows array + bounds checks to be represented conveniently as `(i >= 0 && i < + 10) ? i : abort()'. + + As a GNU extension, the C language front-ends allow the second + operand of the `?:' operator may be omitted in the source. For + example, `x ? : 3' is equivalent to `x ? x : 3', assuming that `x' + is an expression without side-effects. In the tree + representation, however, the second operand is always present, + possibly protected by `SAVE_EXPR' if the first argument does cause + side-effects. + +`CALL_EXPR' + These nodes are used to represent calls to functions, including + non-static member functions. `CALL_EXPR's are implemented as + expression nodes with a variable number of operands. Rather than + using `TREE_OPERAND' to extract them, it is preferable to use the + specialized accessor macros and functions that operate + specifically on `CALL_EXPR' nodes. + + `CALL_EXPR_FN' returns a pointer to the function to call; it is + always an expression whose type is a `POINTER_TYPE'. + + The number of arguments to the call is returned by + `call_expr_nargs', while the arguments themselves can be accessed + with the `CALL_EXPR_ARG' macro. The arguments are zero-indexed + and numbered left-to-right. You can iterate over the arguments + using `FOR_EACH_CALL_EXPR_ARG', as in: + + tree call, arg; + call_expr_arg_iterator iter; + FOR_EACH_CALL_EXPR_ARG (arg, iter, call) + /* arg is bound to successive arguments of call. */ + ...; + + For non-static member functions, there will be an operand + corresponding to the `this' pointer. There will always be + expressions corresponding to all of the arguments, even if the + function is declared with default arguments and some arguments are + not explicitly provided at the call sites. + + `CALL_EXPR's also have a `CALL_EXPR_STATIC_CHAIN' operand that is + used to implement nested functions. This operand is otherwise + null. + +`CLEANUP_POINT_EXPR' + These nodes represent full-expressions. The single operand is an + expression to evaluate. Any destructor calls engendered by the + creation of temporaries during the evaluation of that expression + should be performed immediately after the expression is evaluated. + +`CONSTRUCTOR' + These nodes represent the brace-enclosed initializers for a + structure or array. The first operand is reserved for use by the + back end. The second operand is a `TREE_LIST'. If the + `TREE_TYPE' of the `CONSTRUCTOR' is a `RECORD_TYPE' or + `UNION_TYPE', then the `TREE_PURPOSE' of each node in the + `TREE_LIST' will be a `FIELD_DECL' and the `TREE_VALUE' of each + node will be the expression used to initialize that field. + + If the `TREE_TYPE' of the `CONSTRUCTOR' is an `ARRAY_TYPE', then + the `TREE_PURPOSE' of each element in the `TREE_LIST' will be an + `INTEGER_CST' or a `RANGE_EXPR' of two `INTEGER_CST's. A single + `INTEGER_CST' indicates which element of the array (indexed from + zero) is being assigned to. A `RANGE_EXPR' indicates an inclusive + range of elements to initialize. In both cases the `TREE_VALUE' + is the corresponding initializer. It is re-evaluated for each + element of a `RANGE_EXPR'. If the `TREE_PURPOSE' is `NULL_TREE', + then the initializer is for the next available array element. + + In the front end, you should not depend on the fields appearing in + any particular order. However, in the middle end, fields must + appear in declaration order. You should not assume that all + fields will be represented. Unrepresented fields will be set to + zero. + +`COMPOUND_LITERAL_EXPR' + These nodes represent ISO C99 compound literals. The + `COMPOUND_LITERAL_EXPR_DECL_EXPR' is a `DECL_EXPR' containing an + anonymous `VAR_DECL' for the unnamed object represented by the + compound literal; the `DECL_INITIAL' of that `VAR_DECL' is a + `CONSTRUCTOR' representing the brace-enclosed list of initializers + in the compound literal. That anonymous `VAR_DECL' can also be + accessed directly by the `COMPOUND_LITERAL_EXPR_DECL' macro. + +`SAVE_EXPR' + A `SAVE_EXPR' represents an expression (possibly involving + side-effects) that is used more than once. The side-effects should + occur only the first time the expression is evaluated. Subsequent + uses should just reuse the computed value. The first operand to + the `SAVE_EXPR' is the expression to evaluate. The side-effects + should be executed where the `SAVE_EXPR' is first encountered in a + depth-first preorder traversal of the expression tree. + +`TARGET_EXPR' + A `TARGET_EXPR' represents a temporary object. The first operand + is a `VAR_DECL' for the temporary variable. The second operand is + the initializer for the temporary. The initializer is evaluated + and, if non-void, copied (bitwise) into the temporary. If the + initializer is void, that means that it will perform the + initialization itself. + + Often, a `TARGET_EXPR' occurs on the right-hand side of an + assignment, or as the second operand to a comma-expression which is + itself the right-hand side of an assignment, etc. In this case, + we say that the `TARGET_EXPR' is "normal"; otherwise, we say it is + "orphaned". For a normal `TARGET_EXPR' the temporary variable + should be treated as an alias for the left-hand side of the + assignment, rather than as a new temporary variable. + + The third operand to the `TARGET_EXPR', if present, is a + cleanup-expression (i.e., destructor call) for the temporary. If + this expression is orphaned, then this expression must be executed + when the statement containing this expression is complete. These + cleanups must always be executed in the order opposite to that in + which they were encountered. Note that if a temporary is created + on one branch of a conditional operator (i.e., in the second or + third operand to a `COND_EXPR'), the cleanup must be run only if + that branch is actually executed. + +`VA_ARG_EXPR' + This node is used to implement support for the C/C++ variable + argument-list mechanism. It represents expressions like `va_arg + (ap, type)'. Its `TREE_TYPE' yields the tree representation for + `type' and its sole argument yields the representation for `ap'. + + + +File: gccint.info, Node: Vectors, Prev: Unary and Binary Expressions, Up: Expression trees + +11.6.4 Vectors +-------------- + +`VEC_LSHIFT_EXPR' +`VEC_RSHIFT_EXPR' + These nodes represent whole vector left and right shifts, + respectively. The first operand is the vector to shift; it will + always be of vector type. The second operand is an expression for + the number of bits by which to shift. Note that the result is + undefined if the second operand is larger than or equal to the + first operand's type size. + +`VEC_WIDEN_MULT_HI_EXPR' +`VEC_WIDEN_MULT_LO_EXPR' + These nodes represent widening vector multiplication of the high + and low parts of the two input vectors, respectively. Their + operands are vectors that contain the same number of elements + (`N') of the same integral type. The result is a vector that + contains half as many elements, of an integral type whose size is + twice as wide. In the case of `VEC_WIDEN_MULT_HI_EXPR' the high + `N/2' elements of the two vector are multiplied to produce the + vector of `N/2' products. In the case of `VEC_WIDEN_MULT_LO_EXPR' + the low `N/2' elements of the two vector are multiplied to produce + the vector of `N/2' products. + +`VEC_UNPACK_HI_EXPR' +`VEC_UNPACK_LO_EXPR' + These nodes represent unpacking of the high and low parts of the + input vector, respectively. The single operand is a vector that + contains `N' elements of the same integral or floating point type. + The result is a vector that contains half as many elements, of an + integral or floating point type whose size is twice as wide. In + the case of `VEC_UNPACK_HI_EXPR' the high `N/2' elements of the + vector are extracted and widened (promoted). In the case of + `VEC_UNPACK_LO_EXPR' the low `N/2' elements of the vector are + extracted and widened (promoted). + +`VEC_UNPACK_FLOAT_HI_EXPR' +`VEC_UNPACK_FLOAT_LO_EXPR' + These nodes represent unpacking of the high and low parts of the + input vector, where the values are converted from fixed point to + floating point. The single operand is a vector that contains `N' + elements of the same integral type. The result is a vector that + contains half as many elements of a floating point type whose size + is twice as wide. In the case of `VEC_UNPACK_HI_EXPR' the high + `N/2' elements of the vector are extracted, converted and widened. + In the case of `VEC_UNPACK_LO_EXPR' the low `N/2' elements of the + vector are extracted, converted and widened. + +`VEC_PACK_TRUNC_EXPR' + This node represents packing of truncated elements of the two + input vectors into the output vector. Input operands are vectors + that contain the same number of elements of the same integral or + floating point type. The result is a vector that contains twice + as many elements of an integral or floating point type whose size + is half as wide. The elements of the two vectors are demoted and + merged (concatenated) to form the output vector. + +`VEC_PACK_SAT_EXPR' + This node represents packing of elements of the two input vectors + into the output vector using saturation. Input operands are + vectors that contain the same number of elements of the same + integral type. The result is a vector that contains twice as many + elements of an integral type whose size is half as wide. The + elements of the two vectors are demoted and merged (concatenated) + to form the output vector. + +`VEC_PACK_FIX_TRUNC_EXPR' + This node represents packing of elements of the two input vectors + into the output vector, where the values are converted from + floating point to fixed point. Input operands are vectors that + contain the same number of elements of a floating point type. The + result is a vector that contains twice as many elements of an + integral type whose size is half as wide. The elements of the two + vectors are merged (concatenated) to form the output vector. + +`VEC_EXTRACT_EVEN_EXPR' +`VEC_EXTRACT_ODD_EXPR' + These nodes represent extracting of the even/odd elements of the + two input vectors, respectively. Their operands and result are + vectors that contain the same number of elements of the same type. + +`VEC_INTERLEAVE_HIGH_EXPR' +`VEC_INTERLEAVE_LOW_EXPR' + These nodes represent merging and interleaving of the high/low + elements of the two input vectors, respectively. The operands and + the result are vectors that contain the same number of elements + (`N') of the same type. In the case of + `VEC_INTERLEAVE_HIGH_EXPR', the high `N/2' elements of the first + input vector are interleaved with the high `N/2' elements of the + second input vector. In the case of `VEC_INTERLEAVE_LOW_EXPR', the + low `N/2' elements of the first input vector are interleaved with + the low `N/2' elements of the second input vector. + + + +File: gccint.info, Node: Statements, Next: Functions, Prev: Expression trees, Up: GENERIC + +11.7 Statements +=============== + +Most statements in GIMPLE are assignment statements, represented by +`GIMPLE_ASSIGN'. No other C expressions can appear at statement level; +a reference to a volatile object is converted into a `GIMPLE_ASSIGN'. + + There are also several varieties of complex statements. + +* Menu: + +* Basic Statements:: +* Blocks:: +* Statement Sequences:: +* Empty Statements:: +* Jumps:: +* Cleanups:: +* OpenMP:: + + +File: gccint.info, Node: Basic Statements, Next: Blocks, Up: Statements + +11.7.1 Basic Statements +----------------------- + +`ASM_EXPR' + Used to represent an inline assembly statement. For an inline + assembly statement like: + asm ("mov x, y"); + The `ASM_STRING' macro will return a `STRING_CST' node for `"mov + x, y"'. If the original statement made use of the + extended-assembly syntax, then `ASM_OUTPUTS', `ASM_INPUTS', and + `ASM_CLOBBERS' will be the outputs, inputs, and clobbers for the + statement, represented as `STRING_CST' nodes. The + extended-assembly syntax looks like: + asm ("fsinx %1,%0" : "=f" (result) : "f" (angle)); + The first string is the `ASM_STRING', containing the instruction + template. The next two strings are the output and inputs, + respectively; this statement has no clobbers. As this example + indicates, "plain" assembly statements are merely a special case + of extended assembly statements; they have no cv-qualifiers, + outputs, inputs, or clobbers. All of the strings will be + `NUL'-terminated, and will contain no embedded `NUL'-characters. + + If the assembly statement is declared `volatile', or if the + statement was not an extended assembly statement, and is therefore + implicitly volatile, then the predicate `ASM_VOLATILE_P' will hold + of the `ASM_EXPR'. + +`DECL_EXPR' + Used to represent a local declaration. The `DECL_EXPR_DECL' macro + can be used to obtain the entity declared. This declaration may + be a `LABEL_DECL', indicating that the label declared is a local + label. (As an extension, GCC allows the declaration of labels + with scope.) In C, this declaration may be a `FUNCTION_DECL', + indicating the use of the GCC nested function extension. For more + information, *note Functions::. + +`LABEL_EXPR' + Used to represent a label. The `LABEL_DECL' declared by this + statement can be obtained with the `LABEL_EXPR_LABEL' macro. The + `IDENTIFIER_NODE' giving the name of the label can be obtained from + the `LABEL_DECL' with `DECL_NAME'. + +`GOTO_EXPR' + Used to represent a `goto' statement. The `GOTO_DESTINATION' will + usually be a `LABEL_DECL'. However, if the "computed goto" + extension has been used, the `GOTO_DESTINATION' will be an + arbitrary expression indicating the destination. This expression + will always have pointer type. + +`RETURN_EXPR' + Used to represent a `return' statement. Operand 0 represents the + value to return. It should either be the `RESULT_DECL' for the + containing function, or a `MODIFY_EXPR' or `INIT_EXPR' setting the + function's `RESULT_DECL'. It will be `NULL_TREE' if the statement + was just + return; + +`LOOP_EXPR' + These nodes represent "infinite" loops. The `LOOP_EXPR_BODY' + represents the body of the loop. It should be executed forever, + unless an `EXIT_EXPR' is encountered. + +`EXIT_EXPR' + These nodes represent conditional exits from the nearest enclosing + `LOOP_EXPR'. The single operand is the condition; if it is + nonzero, then the loop should be exited. An `EXIT_EXPR' will only + appear within a `LOOP_EXPR'. + +`SWITCH_STMT' + Used to represent a `switch' statement. The `SWITCH_STMT_COND' is + the expression on which the switch is occurring. See the + documentation for an `IF_STMT' for more information on the + representation used for the condition. The `SWITCH_STMT_BODY' is + the body of the switch statement. The `SWITCH_STMT_TYPE' is the + original type of switch expression as given in the source, before + any compiler conversions. + +`CASE_LABEL_EXPR' + Use to represent a `case' label, range of `case' labels, or a + `default' label. If `CASE_LOW' is `NULL_TREE', then this is a + `default' label. Otherwise, if `CASE_HIGH' is `NULL_TREE', then + this is an ordinary `case' label. In this case, `CASE_LOW' is an + expression giving the value of the label. Both `CASE_LOW' and + `CASE_HIGH' are `INTEGER_CST' nodes. These values will have the + same type as the condition expression in the switch statement. + + Otherwise, if both `CASE_LOW' and `CASE_HIGH' are defined, the + statement is a range of case labels. Such statements originate + with the extension that allows users to write things of the form: + case 2 ... 5: + The first value will be `CASE_LOW', while the second will be + `CASE_HIGH'. + + + +File: gccint.info, Node: Blocks, Next: Statement Sequences, Prev: Basic Statements, Up: Statements + +11.7.2 Blocks +------------- + +Block scopes and the variables they declare in GENERIC are expressed +using the `BIND_EXPR' code, which in previous versions of GCC was +primarily used for the C statement-expression extension. + + Variables in a block are collected into `BIND_EXPR_VARS' in +declaration order through their `TREE_CHAIN' field. Any runtime +initialization is moved out of `DECL_INITIAL' and into a statement in +the controlled block. When gimplifying from C or C++, this +initialization replaces the `DECL_STMT'. These variables will never +require cleanups. The scope of these variables is just the body + + Variable-length arrays (VLAs) complicate this process, as their size +often refers to variables initialized earlier in the block. To handle +this, we currently split the block at that point, and move the VLA into +a new, inner `BIND_EXPR'. This strategy may change in the future. + + A C++ program will usually contain more `BIND_EXPR's than there are +syntactic blocks in the source code, since several C++ constructs have +implicit scopes associated with them. On the other hand, although the +C++ front end uses pseudo-scopes to handle cleanups for objects with +destructors, these don't translate into the GIMPLE form; multiple +declarations at the same level use the same `BIND_EXPR'. + + +File: gccint.info, Node: Statement Sequences, Next: Empty Statements, Prev: Blocks, Up: Statements + +11.7.3 Statement Sequences +-------------------------- + +Multiple statements at the same nesting level are collected into a +`STATEMENT_LIST'. Statement lists are modified and traversed using the +interface in `tree-iterator.h'. + + +File: gccint.info, Node: Empty Statements, Next: Jumps, Prev: Statement Sequences, Up: Statements + +11.7.4 Empty Statements +----------------------- + +Whenever possible, statements with no effect are discarded. But if +they are nested within another construct which cannot be discarded for +some reason, they are instead replaced with an empty statement, +generated by `build_empty_stmt'. Initially, all empty statements were +shared, after the pattern of the Java front end, but this caused a lot +of trouble in practice. + + An empty statement is represented as `(void)0'. + + +File: gccint.info, Node: Jumps, Next: Cleanups, Prev: Empty Statements, Up: Statements + +11.7.5 Jumps +------------ + +Other jumps are expressed by either `GOTO_EXPR' or `RETURN_EXPR'. + + The operand of a `GOTO_EXPR' must be either a label or a variable +containing the address to jump to. + + The operand of a `RETURN_EXPR' is either `NULL_TREE', `RESULT_DECL', +or a `MODIFY_EXPR' which sets the return value. It would be nice to +move the `MODIFY_EXPR' into a separate statement, but the special +return semantics in `expand_return' make that difficult. It may still +happen in the future, perhaps by moving most of that logic into +`expand_assignment'. + + +File: gccint.info, Node: Cleanups, Next: OpenMP, Prev: Jumps, Up: Statements + +11.7.6 Cleanups +--------------- + +Destructors for local C++ objects and similar dynamic cleanups are +represented in GIMPLE by a `TRY_FINALLY_EXPR'. `TRY_FINALLY_EXPR' has +two operands, both of which are a sequence of statements to execute. +The first sequence is executed. When it completes the second sequence +is executed. + + The first sequence may complete in the following ways: + + 1. Execute the last statement in the sequence and fall off the end. + + 2. Execute a goto statement (`GOTO_EXPR') to an ordinary label + outside the sequence. + + 3. Execute a return statement (`RETURN_EXPR'). + + 4. Throw an exception. This is currently not explicitly represented + in GIMPLE. + + + The second sequence is not executed if the first sequence completes by +calling `setjmp' or `exit' or any other function that does not return. +The second sequence is also not executed if the first sequence +completes via a non-local goto or a computed goto (in general the +compiler does not know whether such a goto statement exits the first +sequence or not, so we assume that it doesn't). + + After the second sequence is executed, if it completes normally by +falling off the end, execution continues wherever the first sequence +would have continued, by falling off the end, or doing a goto, etc. + + `TRY_FINALLY_EXPR' complicates the flow graph, since the cleanup needs +to appear on every edge out of the controlled block; this reduces the +freedom to move code across these edges. Therefore, the EH lowering +pass which runs before most of the optimization passes eliminates these +expressions by explicitly adding the cleanup to each edge. Rethrowing +the exception is represented using `RESX_EXPR'. + + +File: gccint.info, Node: OpenMP, Prev: Cleanups, Up: Statements + +11.7.7 OpenMP +------------- + +All the statements starting with `OMP_' represent directives and +clauses used by the OpenMP API `http://www.openmp.org/'. + +`OMP_PARALLEL' + Represents `#pragma omp parallel [clause1 ... clauseN]'. It has + four operands: + + Operand `OMP_PARALLEL_BODY' is valid while in GENERIC and High + GIMPLE forms. It contains the body of code to be executed by all + the threads. During GIMPLE lowering, this operand becomes `NULL' + and the body is emitted linearly after `OMP_PARALLEL'. + + Operand `OMP_PARALLEL_CLAUSES' is the list of clauses associated + with the directive. + + Operand `OMP_PARALLEL_FN' is created by `pass_lower_omp', it + contains the `FUNCTION_DECL' for the function that will contain + the body of the parallel region. + + Operand `OMP_PARALLEL_DATA_ARG' is also created by + `pass_lower_omp'. If there are shared variables to be communicated + to the children threads, this operand will contain the `VAR_DECL' + that contains all the shared values and variables. + +`OMP_FOR' + Represents `#pragma omp for [clause1 ... clauseN]'. It has 5 + operands: + + Operand `OMP_FOR_BODY' contains the loop body. + + Operand `OMP_FOR_CLAUSES' is the list of clauses associated with + the directive. + + Operand `OMP_FOR_INIT' is the loop initialization code of the form + `VAR = N1'. + + Operand `OMP_FOR_COND' is the loop conditional expression of the + form `VAR {<,>,<=,>=} N2'. + + Operand `OMP_FOR_INCR' is the loop index increment of the form + `VAR {+=,-=} INCR'. + + Operand `OMP_FOR_PRE_BODY' contains side-effect code from operands + `OMP_FOR_INIT', `OMP_FOR_COND' and `OMP_FOR_INC'. These + side-effects are part of the `OMP_FOR' block but must be evaluated + before the start of loop body. + + The loop index variable `VAR' must be a signed integer variable, + which is implicitly private to each thread. Bounds `N1' and `N2' + and the increment expression `INCR' are required to be loop + invariant integer expressions that are evaluated without any + synchronization. The evaluation order, frequency of evaluation and + side-effects are unspecified by the standard. + +`OMP_SECTIONS' + Represents `#pragma omp sections [clause1 ... clauseN]'. + + Operand `OMP_SECTIONS_BODY' contains the sections body, which in + turn contains a set of `OMP_SECTION' nodes for each of the + concurrent sections delimited by `#pragma omp section'. + + Operand `OMP_SECTIONS_CLAUSES' is the list of clauses associated + with the directive. + +`OMP_SECTION' + Section delimiter for `OMP_SECTIONS'. + +`OMP_SINGLE' + Represents `#pragma omp single'. + + Operand `OMP_SINGLE_BODY' contains the body of code to be executed + by a single thread. + + Operand `OMP_SINGLE_CLAUSES' is the list of clauses associated + with the directive. + +`OMP_MASTER' + Represents `#pragma omp master'. + + Operand `OMP_MASTER_BODY' contains the body of code to be executed + by the master thread. + +`OMP_ORDERED' + Represents `#pragma omp ordered'. + + Operand `OMP_ORDERED_BODY' contains the body of code to be + executed in the sequential order dictated by the loop index + variable. + +`OMP_CRITICAL' + Represents `#pragma omp critical [name]'. + + Operand `OMP_CRITICAL_BODY' is the critical section. + + Operand `OMP_CRITICAL_NAME' is an optional identifier to label the + critical section. + +`OMP_RETURN' + This does not represent any OpenMP directive, it is an artificial + marker to indicate the end of the body of an OpenMP. It is used by + the flow graph (`tree-cfg.c') and OpenMP region building code + (`omp-low.c'). + +`OMP_CONTINUE' + Similarly, this instruction does not represent an OpenMP + directive, it is used by `OMP_FOR' and `OMP_SECTIONS' to mark the + place where the code needs to loop to the next iteration (in the + case of `OMP_FOR') or the next section (in the case of + `OMP_SECTIONS'). + + In some cases, `OMP_CONTINUE' is placed right before `OMP_RETURN'. + But if there are cleanups that need to occur right after the + looping body, it will be emitted between `OMP_CONTINUE' and + `OMP_RETURN'. + +`OMP_ATOMIC' + Represents `#pragma omp atomic'. + + Operand 0 is the address at which the atomic operation is to be + performed. + + Operand 1 is the expression to evaluate. The gimplifier tries + three alternative code generation strategies. Whenever possible, + an atomic update built-in is used. If that fails, a + compare-and-swap loop is attempted. If that also fails, a regular + critical section around the expression is used. + +`OMP_CLAUSE' + Represents clauses associated with one of the `OMP_' directives. + Clauses are represented by separate sub-codes defined in `tree.h'. + Clauses codes can be one of: `OMP_CLAUSE_PRIVATE', + `OMP_CLAUSE_SHARED', `OMP_CLAUSE_FIRSTPRIVATE', + `OMP_CLAUSE_LASTPRIVATE', `OMP_CLAUSE_COPYIN', + `OMP_CLAUSE_COPYPRIVATE', `OMP_CLAUSE_IF', + `OMP_CLAUSE_NUM_THREADS', `OMP_CLAUSE_SCHEDULE', + `OMP_CLAUSE_NOWAIT', `OMP_CLAUSE_ORDERED', `OMP_CLAUSE_DEFAULT', + and `OMP_CLAUSE_REDUCTION'. Each code represents the + corresponding OpenMP clause. + + Clauses associated with the same directive are chained together + via `OMP_CLAUSE_CHAIN'. Those clauses that accept a list of + variables are restricted to exactly one, accessed with + `OMP_CLAUSE_VAR'. Therefore, multiple variables under the same + clause `C' need to be represented as multiple `C' clauses chained + together. This facilitates adding new clauses during compilation. + + + +File: gccint.info, Node: Functions, Next: Language-dependent trees, Prev: Statements, Up: GENERIC + +11.8 Functions +============== + +A function is represented by a `FUNCTION_DECL' node. It stores the +basic pieces of the function such as body, parameters, and return type +as well as information on the surrounding context, visibility, and +linkage. + +* Menu: + +* Function Basics:: Function names, body, and parameters. +* Function Properties:: Context, linkage, etc. + + +File: gccint.info, Node: Function Basics, Next: Function Properties, Up: Functions + +11.8.1 Function Basics +---------------------- + +A function has four core parts: the name, the parameters, the result, +and the body. The following macros and functions access these parts of +a `FUNCTION_DECL' as well as other basic features: +`DECL_NAME' + This macro returns the unqualified name of the function, as an + `IDENTIFIER_NODE'. For an instantiation of a function template, + the `DECL_NAME' is the unqualified name of the template, not + something like `f<int>'. The value of `DECL_NAME' is undefined + when used on a constructor, destructor, overloaded operator, or + type-conversion operator, or any function that is implicitly + generated by the compiler. See below for macros that can be used + to distinguish these cases. + +`DECL_ASSEMBLER_NAME' + This macro returns the mangled name of the function, also an + `IDENTIFIER_NODE'. This name does not contain leading underscores + on systems that prefix all identifiers with underscores. The + mangled name is computed in the same way on all platforms; if + special processing is required to deal with the object file format + used on a particular platform, it is the responsibility of the + back end to perform those modifications. (Of course, the back end + should not modify `DECL_ASSEMBLER_NAME' itself.) + + Using `DECL_ASSEMBLER_NAME' will cause additional memory to be + allocated (for the mangled name of the entity) so it should be used + only when emitting assembly code. It should not be used within the + optimizers to determine whether or not two declarations are the + same, even though some of the existing optimizers do use it in + that way. These uses will be removed over time. + +`DECL_ARGUMENTS' + This macro returns the `PARM_DECL' for the first argument to the + function. Subsequent `PARM_DECL' nodes can be obtained by + following the `TREE_CHAIN' links. + +`DECL_RESULT' + This macro returns the `RESULT_DECL' for the function. + +`DECL_SAVED_TREE' + This macro returns the complete body of the function. + +`TREE_TYPE' + This macro returns the `FUNCTION_TYPE' or `METHOD_TYPE' for the + function. + +`DECL_INITIAL' + A function that has a definition in the current translation unit + will have a non-`NULL' `DECL_INITIAL'. However, back ends should + not make use of the particular value given by `DECL_INITIAL'. + + It should contain a tree of `BLOCK' nodes that mirrors the scopes + that variables are bound in the function. Each block contains a + list of decls declared in a basic block, a pointer to a chain of + blocks at the next lower scope level, then a pointer to the next + block at the same level and a backpointer to the parent `BLOCK' or + `FUNCTION_DECL'. So given a function as follows: + + void foo() + { + int a; + { + int b; + } + int c; + } + + you would get the following: + + tree foo = FUNCTION_DECL; + tree decl_a = VAR_DECL; + tree decl_b = VAR_DECL; + tree decl_c = VAR_DECL; + tree block_a = BLOCK; + tree block_b = BLOCK; + tree block_c = BLOCK; + BLOCK_VARS(block_a) = decl_a; + BLOCK_SUBBLOCKS(block_a) = block_b; + BLOCK_CHAIN(block_a) = block_c; + BLOCK_SUPERCONTEXT(block_a) = foo; + BLOCK_VARS(block_b) = decl_b; + BLOCK_SUPERCONTEXT(block_b) = block_a; + BLOCK_VARS(block_c) = decl_c; + BLOCK_SUPERCONTEXT(block_c) = foo; + DECL_INITIAL(foo) = block_a; + + + +File: gccint.info, Node: Function Properties, Prev: Function Basics, Up: Functions + +11.8.2 Function Properties +-------------------------- + +To determine the scope of a function, you can use the `DECL_CONTEXT' +macro. This macro will return the class (either a `RECORD_TYPE' or a +`UNION_TYPE') or namespace (a `NAMESPACE_DECL') of which the function +is a member. For a virtual function, this macro returns the class in +which the function was actually defined, not the base class in which +the virtual declaration occurred. + + In C, the `DECL_CONTEXT' for a function maybe another function. This +representation indicates that the GNU nested function extension is in +use. For details on the semantics of nested functions, see the GCC +Manual. The nested function can refer to local variables in its +containing function. Such references are not explicitly marked in the +tree structure; back ends must look at the `DECL_CONTEXT' for the +referenced `VAR_DECL'. If the `DECL_CONTEXT' for the referenced +`VAR_DECL' is not the same as the function currently being processed, +and neither `DECL_EXTERNAL' nor `TREE_STATIC' hold, then the reference +is to a local variable in a containing function, and the back end must +take appropriate action. + +`DECL_EXTERNAL' + This predicate holds if the function is undefined. + +`TREE_PUBLIC' + This predicate holds if the function has external linkage. + +`TREE_STATIC' + This predicate holds if the function has been defined. + +`TREE_THIS_VOLATILE' + This predicate holds if the function does not return normally. + +`TREE_READONLY' + This predicate holds if the function can only read its arguments. + +`DECL_PURE_P' + This predicate holds if the function can only read its arguments, + but may also read global memory. + +`DECL_VIRTUAL_P' + This predicate holds if the function is virtual. + +`DECL_ARTIFICIAL' + This macro holds if the function was implicitly generated by the + compiler, rather than explicitly declared. In addition to + implicitly generated class member functions, this macro holds for + the special functions created to implement static initialization + and destruction, to compute run-time type information, and so + forth. + +`DECL_FUNCTION_SPECIFIC_TARGET' + This macro returns a tree node that holds the target options that + are to be used to compile this particular function or `NULL_TREE' + if the function is to be compiled with the target options + specified on the command line. + +`DECL_FUNCTION_SPECIFIC_OPTIMIZATION' + This macro returns a tree node that holds the optimization options + that are to be used to compile this particular function or + `NULL_TREE' if the function is to be compiled with the + optimization options specified on the command line. + + + +File: gccint.info, Node: Language-dependent trees, Next: C and C++ Trees, Prev: Functions, Up: GENERIC + +11.9 Language-dependent trees +============================= + +Front ends may wish to keep some state associated with various GENERIC +trees while parsing. To support this, trees provide a set of flags +that may be used by the front end. They are accessed using +`TREE_LANG_FLAG_n' where `n' is currently 0 through 6. + + If necessary, a front end can use some language-dependent tree codes +in its GENERIC representation, so long as it provides a hook for +converting them to GIMPLE and doesn't expect them to work with any +(hypothetical) optimizers that run before the conversion to GIMPLE. The +intermediate representation used while parsing C and C++ looks very +little like GENERIC, but the C and C++ gimplifier hooks are perfectly +happy to take it as input and spit out GIMPLE. + + +File: gccint.info, Node: C and C++ Trees, Next: Java Trees, Prev: Language-dependent trees, Up: GENERIC + +11.10 C and C++ Trees +===================== + +This section documents the internal representation used by GCC to +represent C and C++ source programs. When presented with a C or C++ +source program, GCC parses the program, performs semantic analysis +(including the generation of error messages), and then produces the +internal representation described here. This representation contains a +complete representation for the entire translation unit provided as +input to the front end. This representation is then typically processed +by a code-generator in order to produce machine code, but could also be +used in the creation of source browsers, intelligent editors, automatic +documentation generators, interpreters, and any other programs needing +the ability to process C or C++ code. + + This section explains the internal representation. In particular, it +documents the internal representation for C and C++ source constructs, +and the macros, functions, and variables that can be used to access +these constructs. The C++ representation is largely a superset of the +representation used in the C front end. There is only one construct +used in C that does not appear in the C++ front end and that is the GNU +"nested function" extension. Many of the macros documented here do not +apply in C because the corresponding language constructs do not appear +in C. + + The C and C++ front ends generate a mix of GENERIC trees and ones +specific to C and C++. These language-specific trees are higher-level +constructs than the ones in GENERIC to make the parser's job easier. +This section describes those trees that aren't part of GENERIC as well +as aspects of GENERIC trees that are treated in a language-specific +manner. + + If you are developing a "back end", be it is a code-generator or some +other tool, that uses this representation, you may occasionally find +that you need to ask questions not easily answered by the functions and +macros available here. If that situation occurs, it is quite likely +that GCC already supports the functionality you desire, but that the +interface is simply not documented here. In that case, you should ask +the GCC maintainers (via mail to <gcc@gcc.gnu.org>) about documenting +the functionality you require. Similarly, if you find yourself writing +functions that do not deal directly with your back end, but instead +might be useful to other people using the GCC front end, you should +submit your patches for inclusion in GCC. + +* Menu: + +* Types for C++:: Fundamental and aggregate types. +* Namespaces:: Namespaces. +* Classes:: Classes. +* Functions for C++:: Overloading and accessors for C++. +* Statements for C++:: Statements specific to C and C++. +* C++ Expressions:: From `typeid' to `throw'. + + +File: gccint.info, Node: Types for C++, Next: Namespaces, Up: C and C++ Trees + +11.10.1 Types for C++ +--------------------- + +In C++, an array type is not qualified; rather the type of the array +elements is qualified. This situation is reflected in the intermediate +representation. The macros described here will always examine the +qualification of the underlying element type when applied to an array +type. (If the element type is itself an array, then the recursion +continues until a non-array type is found, and the qualification of this +type is examined.) So, for example, `CP_TYPE_CONST_P' will hold of the +type `const int ()[7]', denoting an array of seven `int's. + + The following functions and macros deal with cv-qualification of types: +`CP_TYPE_QUALS' + This macro returns the set of type qualifiers applied to this type. + This value is `TYPE_UNQUALIFIED' if no qualifiers have been + applied. The `TYPE_QUAL_CONST' bit is set if the type is + `const'-qualified. The `TYPE_QUAL_VOLATILE' bit is set if the + type is `volatile'-qualified. The `TYPE_QUAL_RESTRICT' bit is set + if the type is `restrict'-qualified. + +`CP_TYPE_CONST_P' + This macro holds if the type is `const'-qualified. + +`CP_TYPE_VOLATILE_P' + This macro holds if the type is `volatile'-qualified. + +`CP_TYPE_RESTRICT_P' + This macro holds if the type is `restrict'-qualified. + +`CP_TYPE_CONST_NON_VOLATILE_P' + This predicate holds for a type that is `const'-qualified, but + _not_ `volatile'-qualified; other cv-qualifiers are ignored as + well: only the `const'-ness is tested. + + + A few other macros and functions are usable with all types: +`TYPE_SIZE' + The number of bits required to represent the type, represented as + an `INTEGER_CST'. For an incomplete type, `TYPE_SIZE' will be + `NULL_TREE'. + +`TYPE_ALIGN' + The alignment of the type, in bits, represented as an `int'. + +`TYPE_NAME' + This macro returns a declaration (in the form of a `TYPE_DECL') for + the type. (Note this macro does _not_ return an + `IDENTIFIER_NODE', as you might expect, given its name!) You can + look at the `DECL_NAME' of the `TYPE_DECL' to obtain the actual + name of the type. The `TYPE_NAME' will be `NULL_TREE' for a type + that is not a built-in type, the result of a typedef, or a named + class type. + +`CP_INTEGRAL_TYPE' + This predicate holds if the type is an integral type. Notice that + in C++, enumerations are _not_ integral types. + +`ARITHMETIC_TYPE_P' + This predicate holds if the type is an integral type (in the C++ + sense) or a floating point type. + +`CLASS_TYPE_P' + This predicate holds for a class-type. + +`TYPE_BUILT_IN' + This predicate holds for a built-in type. + +`TYPE_PTRMEM_P' + This predicate holds if the type is a pointer to data member. + +`TYPE_PTR_P' + This predicate holds if the type is a pointer type, and the + pointee is not a data member. + +`TYPE_PTRFN_P' + This predicate holds for a pointer to function type. + +`TYPE_PTROB_P' + This predicate holds for a pointer to object type. Note however + that it does not hold for the generic pointer to object type `void + *'. You may use `TYPE_PTROBV_P' to test for a pointer to object + type as well as `void *'. + + + The table below describes types specific to C and C++ as well as +language-dependent info about GENERIC types. + +`POINTER_TYPE' + Used to represent pointer types, and pointer to data member types. + If `TREE_TYPE' is a pointer to data member type, then + `TYPE_PTRMEM_P' will hold. For a pointer to data member type of + the form `T X::*', `TYPE_PTRMEM_CLASS_TYPE' will be the type `X', + while `TYPE_PTRMEM_POINTED_TO_TYPE' will be the type `T'. + +`RECORD_TYPE' + Used to represent `struct' and `class' types in C and C++. If + `TYPE_PTRMEMFUNC_P' holds, then this type is a pointer-to-member + type. In that case, the `TYPE_PTRMEMFUNC_FN_TYPE' is a + `POINTER_TYPE' pointing to a `METHOD_TYPE'. The `METHOD_TYPE' is + the type of a function pointed to by the pointer-to-member + function. If `TYPE_PTRMEMFUNC_P' does not hold, this type is a + class type. For more information, *note Classes::. + +`UNKNOWN_TYPE' + This node is used to represent a type the knowledge of which is + insufficient for a sound processing. + +`TYPENAME_TYPE' + Used to represent a construct of the form `typename T::A'. The + `TYPE_CONTEXT' is `T'; the `TYPE_NAME' is an `IDENTIFIER_NODE' for + `A'. If the type is specified via a template-id, then + `TYPENAME_TYPE_FULLNAME' yields a `TEMPLATE_ID_EXPR'. The + `TREE_TYPE' is non-`NULL' if the node is implicitly generated in + support for the implicit typename extension; in which case the + `TREE_TYPE' is a type node for the base-class. + +`TYPEOF_TYPE' + Used to represent the `__typeof__' extension. The `TYPE_FIELDS' + is the expression the type of which is being represented. + + + +File: gccint.info, Node: Namespaces, Next: Classes, Prev: Types for C++, Up: C and C++ Trees + +11.10.2 Namespaces +------------------ + +The root of the entire intermediate representation is the variable +`global_namespace'. This is the namespace specified with `::' in C++ +source code. All other namespaces, types, variables, functions, and so +forth can be found starting with this namespace. + + However, except for the fact that it is distinguished as the root of +the representation, the global namespace is no different from any other +namespace. Thus, in what follows, we describe namespaces generally, +rather than the global namespace in particular. + + A namespace is represented by a `NAMESPACE_DECL' node. + + The following macros and functions can be used on a `NAMESPACE_DECL': + +`DECL_NAME' + This macro is used to obtain the `IDENTIFIER_NODE' corresponding to + the unqualified name of the name of the namespace (*note + Identifiers::). The name of the global namespace is `::', even + though in C++ the global namespace is unnamed. However, you + should use comparison with `global_namespace', rather than + `DECL_NAME' to determine whether or not a namespace is the global + one. An unnamed namespace will have a `DECL_NAME' equal to + `anonymous_namespace_name'. Within a single translation unit, all + unnamed namespaces will have the same name. + +`DECL_CONTEXT' + This macro returns the enclosing namespace. The `DECL_CONTEXT' for + the `global_namespace' is `NULL_TREE'. + +`DECL_NAMESPACE_ALIAS' + If this declaration is for a namespace alias, then + `DECL_NAMESPACE_ALIAS' is the namespace for which this one is an + alias. + + Do not attempt to use `cp_namespace_decls' for a namespace which is + an alias. Instead, follow `DECL_NAMESPACE_ALIAS' links until you + reach an ordinary, non-alias, namespace, and call + `cp_namespace_decls' there. + +`DECL_NAMESPACE_STD_P' + This predicate holds if the namespace is the special `::std' + namespace. + +`cp_namespace_decls' + This function will return the declarations contained in the + namespace, including types, overloaded functions, other + namespaces, and so forth. If there are no declarations, this + function will return `NULL_TREE'. The declarations are connected + through their `TREE_CHAIN' fields. + + Although most entries on this list will be declarations, + `TREE_LIST' nodes may also appear. In this case, the `TREE_VALUE' + will be an `OVERLOAD'. The value of the `TREE_PURPOSE' is + unspecified; back ends should ignore this value. As with the + other kinds of declarations returned by `cp_namespace_decls', the + `TREE_CHAIN' will point to the next declaration in this list. + + For more information on the kinds of declarations that can occur + on this list, *Note Declarations::. Some declarations will not + appear on this list. In particular, no `FIELD_DECL', + `LABEL_DECL', or `PARM_DECL' nodes will appear here. + + This function cannot be used with namespaces that have + `DECL_NAMESPACE_ALIAS' set. + + + +File: gccint.info, Node: Classes, Next: Functions for C++, Prev: Namespaces, Up: C and C++ Trees + +11.10.3 Classes +--------------- + +Besides namespaces, the other high-level scoping construct in C++ is the +class. (Throughout this manual the term "class" is used to mean the +types referred to in the ANSI/ISO C++ Standard as classes; these include +types defined with the `class', `struct', and `union' keywords.) + + A class type is represented by either a `RECORD_TYPE' or a +`UNION_TYPE'. A class declared with the `union' tag is represented by +a `UNION_TYPE', while classes declared with either the `struct' or the +`class' tag are represented by `RECORD_TYPE's. You can use the +`CLASSTYPE_DECLARED_CLASS' macro to discern whether or not a particular +type is a `class' as opposed to a `struct'. This macro will be true +only for classes declared with the `class' tag. + + Almost all non-function members are available on the `TYPE_FIELDS' +list. Given one member, the next can be found by following the +`TREE_CHAIN'. You should not depend in any way on the order in which +fields appear on this list. All nodes on this list will be `DECL' +nodes. A `FIELD_DECL' is used to represent a non-static data member, a +`VAR_DECL' is used to represent a static data member, and a `TYPE_DECL' +is used to represent a type. Note that the `CONST_DECL' for an +enumeration constant will appear on this list, if the enumeration type +was declared in the class. (Of course, the `TYPE_DECL' for the +enumeration type will appear here as well.) There are no entries for +base classes on this list. In particular, there is no `FIELD_DECL' for +the "base-class portion" of an object. + + The `TYPE_VFIELD' is a compiler-generated field used to point to +virtual function tables. It may or may not appear on the `TYPE_FIELDS' +list. However, back ends should handle the `TYPE_VFIELD' just like all +the entries on the `TYPE_FIELDS' list. + + The function members are available on the `TYPE_METHODS' list. Again, +subsequent members are found by following the `TREE_CHAIN' field. If a +function is overloaded, each of the overloaded functions appears; no +`OVERLOAD' nodes appear on the `TYPE_METHODS' list. Implicitly +declared functions (including default constructors, copy constructors, +assignment operators, and destructors) will appear on this list as well. + + Every class has an associated "binfo", which can be obtained with +`TYPE_BINFO'. Binfos are used to represent base-classes. The binfo +given by `TYPE_BINFO' is the degenerate case, whereby every class is +considered to be its own base-class. The base binfos for a particular +binfo are held in a vector, whose length is obtained with +`BINFO_N_BASE_BINFOS'. The base binfos themselves are obtained with +`BINFO_BASE_BINFO' and `BINFO_BASE_ITERATE'. To add a new binfo, use +`BINFO_BASE_APPEND'. The vector of base binfos can be obtained with +`BINFO_BASE_BINFOS', but normally you do not need to use that. The +class type associated with a binfo is given by `BINFO_TYPE'. It is not +always the case that `BINFO_TYPE (TYPE_BINFO (x))', because of typedefs +and qualified types. Neither is it the case that `TYPE_BINFO +(BINFO_TYPE (y))' is the same binfo as `y'. The reason is that if `y' +is a binfo representing a base-class `B' of a derived class `D', then +`BINFO_TYPE (y)' will be `B', and `TYPE_BINFO (BINFO_TYPE (y))' will be +`B' as its own base-class, rather than as a base-class of `D'. + + The access to a base type can be found with `BINFO_BASE_ACCESS'. This +will produce `access_public_node', `access_private_node' or +`access_protected_node'. If bases are always public, +`BINFO_BASE_ACCESSES' may be `NULL'. + + `BINFO_VIRTUAL_P' is used to specify whether the binfo is inherited +virtually or not. The other flags, `BINFO_MARKED_P' and `BINFO_FLAG_1' +to `BINFO_FLAG_6' can be used for language specific use. + + The following macros can be used on a tree node representing a +class-type. + +`LOCAL_CLASS_P' + This predicate holds if the class is local class _i.e._ declared + inside a function body. + +`TYPE_POLYMORPHIC_P' + This predicate holds if the class has at least one virtual function + (declared or inherited). + +`TYPE_HAS_DEFAULT_CONSTRUCTOR' + This predicate holds whenever its argument represents a class-type + with default constructor. + +`CLASSTYPE_HAS_MUTABLE' +`TYPE_HAS_MUTABLE_P' + These predicates hold for a class-type having a mutable data + member. + +`CLASSTYPE_NON_POD_P' + This predicate holds only for class-types that are not PODs. + +`TYPE_HAS_NEW_OPERATOR' + This predicate holds for a class-type that defines `operator new'. + +`TYPE_HAS_ARRAY_NEW_OPERATOR' + This predicate holds for a class-type for which `operator new[]' + is defined. + +`TYPE_OVERLOADS_CALL_EXPR' + This predicate holds for class-type for which the function call + `operator()' is overloaded. + +`TYPE_OVERLOADS_ARRAY_REF' + This predicate holds for a class-type that overloads `operator[]' + +`TYPE_OVERLOADS_ARROW' + This predicate holds for a class-type for which `operator->' is + overloaded. + + + +File: gccint.info, Node: Functions for C++, Next: Statements for C++, Prev: Classes, Up: C and C++ Trees + +11.10.4 Functions for C++ +------------------------- + +A function is represented by a `FUNCTION_DECL' node. A set of +overloaded functions is sometimes represented by an `OVERLOAD' node. + + An `OVERLOAD' node is not a declaration, so none of the `DECL_' macros +should be used on an `OVERLOAD'. An `OVERLOAD' node is similar to a +`TREE_LIST'. Use `OVL_CURRENT' to get the function associated with an +`OVERLOAD' node; use `OVL_NEXT' to get the next `OVERLOAD' node in the +list of overloaded functions. The macros `OVL_CURRENT' and `OVL_NEXT' +are actually polymorphic; you can use them to work with `FUNCTION_DECL' +nodes as well as with overloads. In the case of a `FUNCTION_DECL', +`OVL_CURRENT' will always return the function itself, and `OVL_NEXT' +will always be `NULL_TREE'. + + To determine the scope of a function, you can use the `DECL_CONTEXT' +macro. This macro will return the class (either a `RECORD_TYPE' or a +`UNION_TYPE') or namespace (a `NAMESPACE_DECL') of which the function +is a member. For a virtual function, this macro returns the class in +which the function was actually defined, not the base class in which +the virtual declaration occurred. + + If a friend function is defined in a class scope, the +`DECL_FRIEND_CONTEXT' macro can be used to determine the class in which +it was defined. For example, in + class C { friend void f() {} }; + the `DECL_CONTEXT' for `f' will be the `global_namespace', but the +`DECL_FRIEND_CONTEXT' will be the `RECORD_TYPE' for `C'. + + The following macros and functions can be used on a `FUNCTION_DECL': +`DECL_MAIN_P' + This predicate holds for a function that is the program entry point + `::code'. + +`DECL_LOCAL_FUNCTION_P' + This predicate holds if the function was declared at block scope, + even though it has a global scope. + +`DECL_ANTICIPATED' + This predicate holds if the function is a built-in function but its + prototype is not yet explicitly declared. + +`DECL_EXTERN_C_FUNCTION_P' + This predicate holds if the function is declared as an ``extern + "C"'' function. + +`DECL_LINKONCE_P' + This macro holds if multiple copies of this function may be + emitted in various translation units. It is the responsibility of + the linker to merge the various copies. Template instantiations + are the most common example of functions for which + `DECL_LINKONCE_P' holds; G++ instantiates needed templates in all + translation units which require them, and then relies on the + linker to remove duplicate instantiations. + + FIXME: This macro is not yet implemented. + +`DECL_FUNCTION_MEMBER_P' + This macro holds if the function is a member of a class, rather + than a member of a namespace. + +`DECL_STATIC_FUNCTION_P' + This predicate holds if the function a static member function. + +`DECL_NONSTATIC_MEMBER_FUNCTION_P' + This macro holds for a non-static member function. + +`DECL_CONST_MEMFUNC_P' + This predicate holds for a `const'-member function. + +`DECL_VOLATILE_MEMFUNC_P' + This predicate holds for a `volatile'-member function. + +`DECL_CONSTRUCTOR_P' + This macro holds if the function is a constructor. + +`DECL_NONCONVERTING_P' + This predicate holds if the constructor is a non-converting + constructor. + +`DECL_COMPLETE_CONSTRUCTOR_P' + This predicate holds for a function which is a constructor for an + object of a complete type. + +`DECL_BASE_CONSTRUCTOR_P' + This predicate holds for a function which is a constructor for a + base class sub-object. + +`DECL_COPY_CONSTRUCTOR_P' + This predicate holds for a function which is a copy-constructor. + +`DECL_DESTRUCTOR_P' + This macro holds if the function is a destructor. + +`DECL_COMPLETE_DESTRUCTOR_P' + This predicate holds if the function is the destructor for an + object a complete type. + +`DECL_OVERLOADED_OPERATOR_P' + This macro holds if the function is an overloaded operator. + +`DECL_CONV_FN_P' + This macro holds if the function is a type-conversion operator. + +`DECL_GLOBAL_CTOR_P' + This predicate holds if the function is a file-scope initialization + function. + +`DECL_GLOBAL_DTOR_P' + This predicate holds if the function is a file-scope finalization + function. + +`DECL_THUNK_P' + This predicate holds if the function is a thunk. + + These functions represent stub code that adjusts the `this' pointer + and then jumps to another function. When the jumped-to function + returns, control is transferred directly to the caller, without + returning to the thunk. The first parameter to the thunk is + always the `this' pointer; the thunk should add `THUNK_DELTA' to + this value. (The `THUNK_DELTA' is an `int', not an `INTEGER_CST'.) + + Then, if `THUNK_VCALL_OFFSET' (an `INTEGER_CST') is nonzero the + adjusted `this' pointer must be adjusted again. The complete + calculation is given by the following pseudo-code: + + this += THUNK_DELTA + if (THUNK_VCALL_OFFSET) + this += (*((ptrdiff_t **) this))[THUNK_VCALL_OFFSET] + + Finally, the thunk should jump to the location given by + `DECL_INITIAL'; this will always be an expression for the address + of a function. + +`DECL_NON_THUNK_FUNCTION_P' + This predicate holds if the function is _not_ a thunk function. + +`GLOBAL_INIT_PRIORITY' + If either `DECL_GLOBAL_CTOR_P' or `DECL_GLOBAL_DTOR_P' holds, then + this gives the initialization priority for the function. The + linker will arrange that all functions for which + `DECL_GLOBAL_CTOR_P' holds are run in increasing order of priority + before `main' is called. When the program exits, all functions for + which `DECL_GLOBAL_DTOR_P' holds are run in the reverse order. + +`TYPE_RAISES_EXCEPTIONS' + This macro returns the list of exceptions that a (member-)function + can raise. The returned list, if non `NULL', is comprised of nodes + whose `TREE_VALUE' represents a type. + +`TYPE_NOTHROW_P' + This predicate holds when the exception-specification of its + arguments is of the form ``()''. + +`DECL_ARRAY_DELETE_OPERATOR_P' + This predicate holds if the function an overloaded `operator + delete[]'. + + + +File: gccint.info, Node: Statements for C++, Next: C++ Expressions, Prev: Functions for C++, Up: C and C++ Trees + +11.10.5 Statements for C++ +-------------------------- + +A function that has a definition in the current translation unit will +have a non-`NULL' `DECL_INITIAL'. However, back ends should not make +use of the particular value given by `DECL_INITIAL'. + + The `DECL_SAVED_TREE' macro will give the complete body of the +function. + +11.10.5.1 Statements +.................... + +There are tree nodes corresponding to all of the source-level statement +constructs, used within the C and C++ frontends. These are enumerated +here, together with a list of the various macros that can be used to +obtain information about them. There are a few macros that can be used +with all statements: + +`STMT_IS_FULL_EXPR_P' + In C++, statements normally constitute "full expressions"; + temporaries created during a statement are destroyed when the + statement is complete. However, G++ sometimes represents + expressions by statements; these statements will not have + `STMT_IS_FULL_EXPR_P' set. Temporaries created during such + statements should be destroyed when the innermost enclosing + statement with `STMT_IS_FULL_EXPR_P' set is exited. + + + Here is the list of the various statement nodes, and the macros used to +access them. This documentation describes the use of these nodes in +non-template functions (including instantiations of template functions). +In template functions, the same nodes are used, but sometimes in +slightly different ways. + + Many of the statements have substatements. For example, a `while' +loop will have a body, which is itself a statement. If the substatement +is `NULL_TREE', it is considered equivalent to a statement consisting +of a single `;', i.e., an expression statement in which the expression +has been omitted. A substatement may in fact be a list of statements, +connected via their `TREE_CHAIN's. So, you should always process the +statement tree by looping over substatements, like this: + void process_stmt (stmt) + tree stmt; + { + while (stmt) + { + switch (TREE_CODE (stmt)) + { + case IF_STMT: + process_stmt (THEN_CLAUSE (stmt)); + /* More processing here. */ + break; + + ... + } + + stmt = TREE_CHAIN (stmt); + } + } + In other words, while the `then' clause of an `if' statement in C++ +can be only one statement (although that one statement may be a +compound statement), the intermediate representation will sometimes use +several statements chained together. + +`BREAK_STMT' + Used to represent a `break' statement. There are no additional + fields. + +`CLEANUP_STMT' + Used to represent an action that should take place upon exit from + the enclosing scope. Typically, these actions are calls to + destructors for local objects, but back ends cannot rely on this + fact. If these nodes are in fact representing such destructors, + `CLEANUP_DECL' will be the `VAR_DECL' destroyed. Otherwise, + `CLEANUP_DECL' will be `NULL_TREE'. In any case, the + `CLEANUP_EXPR' is the expression to execute. The cleanups + executed on exit from a scope should be run in the reverse order + of the order in which the associated `CLEANUP_STMT's were + encountered. + +`CONTINUE_STMT' + Used to represent a `continue' statement. There are no additional + fields. + +`CTOR_STMT' + Used to mark the beginning (if `CTOR_BEGIN_P' holds) or end (if + `CTOR_END_P' holds of the main body of a constructor. See also + `SUBOBJECT' for more information on how to use these nodes. + +`DO_STMT' + Used to represent a `do' loop. The body of the loop is given by + `DO_BODY' while the termination condition for the loop is given by + `DO_COND'. The condition for a `do'-statement is always an + expression. + +`EMPTY_CLASS_EXPR' + Used to represent a temporary object of a class with no data whose + address is never taken. (All such objects are interchangeable.) + The `TREE_TYPE' represents the type of the object. + +`EXPR_STMT' + Used to represent an expression statement. Use `EXPR_STMT_EXPR' to + obtain the expression. + +`FOR_STMT' + Used to represent a `for' statement. The `FOR_INIT_STMT' is the + initialization statement for the loop. The `FOR_COND' is the + termination condition. The `FOR_EXPR' is the expression executed + right before the `FOR_COND' on each loop iteration; often, this + expression increments a counter. The body of the loop is given by + `FOR_BODY'. Note that `FOR_INIT_STMT' and `FOR_BODY' return + statements, while `FOR_COND' and `FOR_EXPR' return expressions. + +`HANDLER' + Used to represent a C++ `catch' block. The `HANDLER_TYPE' is the + type of exception that will be caught by this handler; it is equal + (by pointer equality) to `NULL' if this handler is for all types. + `HANDLER_PARMS' is the `DECL_STMT' for the catch parameter, and + `HANDLER_BODY' is the code for the block itself. + +`IF_STMT' + Used to represent an `if' statement. The `IF_COND' is the + expression. + + If the condition is a `TREE_LIST', then the `TREE_PURPOSE' is a + statement (usually a `DECL_STMT'). Each time the condition is + evaluated, the statement should be executed. Then, the + `TREE_VALUE' should be used as the conditional expression itself. + This representation is used to handle C++ code like this: + + C++ distinguishes between this and `COND_EXPR' for handling + templates. + + if (int i = 7) ... + + where there is a new local variable (or variables) declared within + the condition. + + The `THEN_CLAUSE' represents the statement given by the `then' + condition, while the `ELSE_CLAUSE' represents the statement given + by the `else' condition. + +`SUBOBJECT' + In a constructor, these nodes are used to mark the point at which a + subobject of `this' is fully constructed. If, after this point, an + exception is thrown before a `CTOR_STMT' with `CTOR_END_P' set is + encountered, the `SUBOBJECT_CLEANUP' must be executed. The + cleanups must be executed in the reverse order in which they + appear. + +`SWITCH_STMT' + Used to represent a `switch' statement. The `SWITCH_STMT_COND' is + the expression on which the switch is occurring. See the + documentation for an `IF_STMT' for more information on the + representation used for the condition. The `SWITCH_STMT_BODY' is + the body of the switch statement. The `SWITCH_STMT_TYPE' is the + original type of switch expression as given in the source, before + any compiler conversions. + +`TRY_BLOCK' + Used to represent a `try' block. The body of the try block is + given by `TRY_STMTS'. Each of the catch blocks is a `HANDLER' + node. The first handler is given by `TRY_HANDLERS'. Subsequent + handlers are obtained by following the `TREE_CHAIN' link from one + handler to the next. The body of the handler is given by + `HANDLER_BODY'. + + If `CLEANUP_P' holds of the `TRY_BLOCK', then the `TRY_HANDLERS' + will not be a `HANDLER' node. Instead, it will be an expression + that should be executed if an exception is thrown in the try + block. It must rethrow the exception after executing that code. + And, if an exception is thrown while the expression is executing, + `terminate' must be called. + +`USING_STMT' + Used to represent a `using' directive. The namespace is given by + `USING_STMT_NAMESPACE', which will be a NAMESPACE_DECL. This node + is needed inside template functions, to implement using directives + during instantiation. + +`WHILE_STMT' + Used to represent a `while' loop. The `WHILE_COND' is the + termination condition for the loop. See the documentation for an + `IF_STMT' for more information on the representation used for the + condition. + + The `WHILE_BODY' is the body of the loop. + + + +File: gccint.info, Node: C++ Expressions, Prev: Statements for C++, Up: C and C++ Trees + +11.10.6 C++ Expressions +----------------------- + +This section describes expressions specific to the C and C++ front ends. + +`TYPEID_EXPR' + Used to represent a `typeid' expression. + +`NEW_EXPR' +`VEC_NEW_EXPR' + Used to represent a call to `new' and `new[]' respectively. + +`DELETE_EXPR' +`VEC_DELETE_EXPR' + Used to represent a call to `delete' and `delete[]' respectively. + +`MEMBER_REF' + Represents a reference to a member of a class. + +`THROW_EXPR' + Represents an instance of `throw' in the program. Operand 0, + which is the expression to throw, may be `NULL_TREE'. + +`AGGR_INIT_EXPR' + An `AGGR_INIT_EXPR' represents the initialization as the return + value of a function call, or as the result of a constructor. An + `AGGR_INIT_EXPR' will only appear as a full-expression, or as the + second operand of a `TARGET_EXPR'. `AGGR_INIT_EXPR's have a + representation similar to that of `CALL_EXPR's. You can use the + `AGGR_INIT_EXPR_FN' and `AGGR_INIT_EXPR_ARG' macros to access the + function to call and the arguments to pass. + + If `AGGR_INIT_VIA_CTOR_P' holds of the `AGGR_INIT_EXPR', then the + initialization is via a constructor call. The address of the + `AGGR_INIT_EXPR_SLOT' operand, which is always a `VAR_DECL', is + taken, and this value replaces the first argument in the argument + list. + + In either case, the expression is void. + + + +File: gccint.info, Node: Java Trees, Prev: C and C++ Trees, Up: GENERIC + +11.11 Java Trees +================ + + +File: gccint.info, Node: GIMPLE, Next: Tree SSA, Prev: GENERIC, Up: Top + +12 GIMPLE +********* + +GIMPLE is a three-address representation derived from GENERIC by +breaking down GENERIC expressions into tuples of no more than 3 +operands (with some exceptions like function calls). GIMPLE was +heavily influenced by the SIMPLE IL used by the McCAT compiler project +at McGill University, though we have made some different choices. For +one thing, SIMPLE doesn't support `goto'. + + Temporaries are introduced to hold intermediate values needed to +compute complex expressions. Additionally, all the control structures +used in GENERIC are lowered into conditional jumps, lexical scopes are +removed and exception regions are converted into an on the side +exception region tree. + + The compiler pass which converts GENERIC into GIMPLE is referred to as +the `gimplifier'. The gimplifier works recursively, generating GIMPLE +tuples out of the original GENERIC expressions. + + One of the early implementation strategies used for the GIMPLE +representation was to use the same internal data structures used by +front ends to represent parse trees. This simplified implementation +because we could leverage existing functionality and interfaces. +However, GIMPLE is a much more restrictive representation than abstract +syntax trees (AST), therefore it does not require the full structural +complexity provided by the main tree data structure. + + The GENERIC representation of a function is stored in the +`DECL_SAVED_TREE' field of the associated `FUNCTION_DECL' tree node. +It is converted to GIMPLE by a call to `gimplify_function_tree'. + + If a front end wants to include language-specific tree codes in the +tree representation which it provides to the back end, it must provide a +definition of `LANG_HOOKS_GIMPLIFY_EXPR' which knows how to convert the +front end trees to GIMPLE. Usually such a hook will involve much of +the same code for expanding front end trees to RTL. This function can +return fully lowered GIMPLE, or it can return GENERIC trees and let the +main gimplifier lower them the rest of the way; this is often simpler. +GIMPLE that is not fully lowered is known as "High GIMPLE" and consists +of the IL before the pass `pass_lower_cf'. High GIMPLE contains some +container statements like lexical scopes (represented by `GIMPLE_BIND') +and nested expressions (e.g., `GIMPLE_TRY'), while "Low GIMPLE" exposes +all of the implicit jumps for control and exception expressions +directly in the IL and EH region trees. + + The C and C++ front ends currently convert directly from front end +trees to GIMPLE, and hand that off to the back end rather than first +converting to GENERIC. Their gimplifier hooks know about all the +`_STMT' nodes and how to convert them to GENERIC forms. There was some +work done on a genericization pass which would run first, but the +existence of `STMT_EXPR' meant that in order to convert all of the C +statements into GENERIC equivalents would involve walking the entire +tree anyway, so it was simpler to lower all the way. This might change +in the future if someone writes an optimization pass which would work +better with higher-level trees, but currently the optimizers all expect +GIMPLE. + + You can request to dump a C-like representation of the GIMPLE form +with the flag `-fdump-tree-gimple'. + +* Menu: + +* Tuple representation:: +* GIMPLE instruction set:: +* GIMPLE Exception Handling:: +* Temporaries:: +* Operands:: +* Manipulating GIMPLE statements:: +* Tuple specific accessors:: +* GIMPLE sequences:: +* Sequence iterators:: +* Adding a new GIMPLE statement code:: +* Statement and operand traversals:: + + +File: gccint.info, Node: Tuple representation, Next: GIMPLE instruction set, Up: GIMPLE + +12.1 Tuple representation +========================= + +GIMPLE instructions are tuples of variable size divided in two groups: +a header describing the instruction and its locations, and a variable +length body with all the operands. Tuples are organized into a +hierarchy with 3 main classes of tuples. + +12.1.1 `gimple_statement_base' (gsbase) +--------------------------------------- + +This is the root of the hierarchy, it holds basic information needed by +most GIMPLE statements. There are some fields that may not be relevant +to every GIMPLE statement, but those were moved into the base structure +to take advantage of holes left by other fields (thus making the +structure more compact). The structure takes 4 words (32 bytes) on 64 +bit hosts: + +Field Size (bits) +`code' 8 +`subcode' 16 +`no_warning' 1 +`visited' 1 +`nontemporal_move' 1 +`plf' 2 +`modified' 1 +`has_volatile_ops' 1 +`references_memory_p' 1 +`uid' 32 +`location' 32 +`num_ops' 32 +`bb' 64 +`block' 63 +Total size 32 bytes + + * `code' Main identifier for a GIMPLE instruction. + + * `subcode' Used to distinguish different variants of the same basic + instruction or provide flags applicable to a given code. The + `subcode' flags field has different uses depending on the code of + the instruction, but mostly it distinguishes instructions of the + same family. The most prominent use of this field is in + assignments, where subcode indicates the operation done on the RHS + of the assignment. For example, a = b + c is encoded as + `GIMPLE_ASSIGN <PLUS_EXPR, a, b, c>'. + + * `no_warning' Bitflag to indicate whether a warning has already + been issued on this statement. + + * `visited' General purpose "visited" marker. Set and cleared by + each pass when needed. + + * `nontemporal_move' Bitflag used in assignments that represent + non-temporal moves. Although this bitflag is only used in + assignments, it was moved into the base to take advantage of the + bit holes left by the previous fields. + + * `plf' Pass Local Flags. This 2-bit mask can be used as general + purpose markers by any pass. Passes are responsible for clearing + and setting these two flags accordingly. + + * `modified' Bitflag to indicate whether the statement has been + modified. Used mainly by the operand scanner to determine when to + re-scan a statement for operands. + + * `has_volatile_ops' Bitflag to indicate whether this statement + contains operands that have been marked volatile. + + * `references_memory_p' Bitflag to indicate whether this statement + contains memory references (i.e., its operands are either global + variables, or pointer dereferences or anything that must reside in + memory). + + * `uid' This is an unsigned integer used by passes that want to + assign IDs to every statement. These IDs must be assigned and used + by each pass. + + * `location' This is a `location_t' identifier to specify source code + location for this statement. It is inherited from the front end. + + * `num_ops' Number of operands that this statement has. This + specifies the size of the operand vector embedded in the tuple. + Only used in some tuples, but it is declared in the base tuple to + take advantage of the 32-bit hole left by the previous fields. + + * `bb' Basic block holding the instruction. + + * `block' Lexical block holding this statement. Also used for debug + information generation. + +12.1.2 `gimple_statement_with_ops' +---------------------------------- + +This tuple is actually split in two: `gimple_statement_with_ops_base' +and `gimple_statement_with_ops'. This is needed to accommodate the way +the operand vector is allocated. The operand vector is defined to be an +array of 1 element. So, to allocate a dynamic number of operands, the +memory allocator (`gimple_alloc') simply allocates enough memory to +hold the structure itself plus `N - 1' operands which run "off the end" +of the structure. For example, to allocate space for a tuple with 3 +operands, `gimple_alloc' reserves `sizeof (struct +gimple_statement_with_ops) + 2 * sizeof (tree)' bytes. + + On the other hand, several fields in this tuple need to be shared with +the `gimple_statement_with_memory_ops' tuple. So, these common fields +are placed in `gimple_statement_with_ops_base' which is then inherited +from the other two tuples. + +`gsbase' 256 +`def_ops' 64 +`use_ops' 64 +`op' `num_ops' * 64 +Total size 48 + 8 * `num_ops' bytes + + * `gsbase' Inherited from `struct gimple_statement_base'. + + * `def_ops' Array of pointers into the operand array indicating all + the slots that contain a variable written-to by the statement. + This array is also used for immediate use chaining. Note that it + would be possible to not rely on this array, but the changes + required to implement this are pretty invasive. + + * `use_ops' Similar to `def_ops' but for variables read by the + statement. + + * `op' Array of trees with `num_ops' slots. + +12.1.3 `gimple_statement_with_memory_ops' +----------------------------------------- + +This tuple is essentially identical to `gimple_statement_with_ops', +except that it contains 4 additional fields to hold vectors related +memory stores and loads. Similar to the previous case, the structure +is split in two to accommodate for the operand vector +(`gimple_statement_with_memory_ops_base' and +`gimple_statement_with_memory_ops'). + +Field Size (bits) +`gsbase' 256 +`def_ops' 64 +`use_ops' 64 +`vdef_ops' 64 +`vuse_ops' 64 +`stores' 64 +`loads' 64 +`op' `num_ops' * 64 +Total size 80 + 8 * `num_ops' bytes + + * `vdef_ops' Similar to `def_ops' but for `VDEF' operators. There is + one entry per memory symbol written by this statement. This is + used to maintain the memory SSA use-def and def-def chains. + + * `vuse_ops' Similar to `use_ops' but for `VUSE' operators. There is + one entry per memory symbol loaded by this statement. This is used + to maintain the memory SSA use-def chains. + + * `stores' Bitset with all the UIDs for the symbols written-to by the + statement. This is different than `vdef_ops' in that all the + affected symbols are mentioned in this set. If memory + partitioning is enabled, the `vdef_ops' vector will refer to memory + partitions. Furthermore, no SSA information is stored in this set. + + * `loads' Similar to `stores', but for memory loads. (Note that there + is some amount of redundancy here, it should be possible to reduce + memory utilization further by removing these sets). + + All the other tuples are defined in terms of these three basic ones. +Each tuple will add some fields. The main gimple type is defined to be +the union of all these structures (`GTY' markers elided for clarity): + + union gimple_statement_d + { + struct gimple_statement_base gsbase; + struct gimple_statement_with_ops gsops; + struct gimple_statement_with_memory_ops gsmem; + struct gimple_statement_omp omp; + struct gimple_statement_bind gimple_bind; + struct gimple_statement_catch gimple_catch; + struct gimple_statement_eh_filter gimple_eh_filter; + struct gimple_statement_phi gimple_phi; + struct gimple_statement_resx gimple_resx; + struct gimple_statement_try gimple_try; + struct gimple_statement_wce gimple_wce; + struct gimple_statement_asm gimple_asm; + struct gimple_statement_omp_critical gimple_omp_critical; + struct gimple_statement_omp_for gimple_omp_for; + struct gimple_statement_omp_parallel gimple_omp_parallel; + struct gimple_statement_omp_task gimple_omp_task; + struct gimple_statement_omp_sections gimple_omp_sections; + struct gimple_statement_omp_single gimple_omp_single; + struct gimple_statement_omp_continue gimple_omp_continue; + struct gimple_statement_omp_atomic_load gimple_omp_atomic_load; + struct gimple_statement_omp_atomic_store gimple_omp_atomic_store; + }; + + +File: gccint.info, Node: GIMPLE instruction set, Next: GIMPLE Exception Handling, Prev: Tuple representation, Up: GIMPLE + +12.2 GIMPLE instruction set +=========================== + +The following table briefly describes the GIMPLE instruction set. + +Instruction High GIMPLE Low GIMPLE +`GIMPLE_ASM' x x +`GIMPLE_ASSIGN' x x +`GIMPLE_BIND' x +`GIMPLE_CALL' x x +`GIMPLE_CATCH' x +`GIMPLE_COND' x x +`GIMPLE_DEBUG' x x +`GIMPLE_EH_FILTER' x +`GIMPLE_GOTO' x x +`GIMPLE_LABEL' x x +`GIMPLE_NOP' x x +`GIMPLE_OMP_ATOMIC_LOAD' x x +`GIMPLE_OMP_ATOMIC_STORE' x x +`GIMPLE_OMP_CONTINUE' x x +`GIMPLE_OMP_CRITICAL' x x +`GIMPLE_OMP_FOR' x x +`GIMPLE_OMP_MASTER' x x +`GIMPLE_OMP_ORDERED' x x +`GIMPLE_OMP_PARALLEL' x x +`GIMPLE_OMP_RETURN' x x +`GIMPLE_OMP_SECTION' x x +`GIMPLE_OMP_SECTIONS' x x +`GIMPLE_OMP_SECTIONS_SWITCH' x x +`GIMPLE_OMP_SINGLE' x x +`GIMPLE_PHI' x +`GIMPLE_RESX' x +`GIMPLE_RETURN' x x +`GIMPLE_SWITCH' x x +`GIMPLE_TRY' x + + +File: gccint.info, Node: GIMPLE Exception Handling, Next: Temporaries, Prev: GIMPLE instruction set, Up: GIMPLE + +12.3 Exception Handling +======================= + +Other exception handling constructs are represented using +`GIMPLE_TRY_CATCH'. `GIMPLE_TRY_CATCH' has two operands. The first +operand is a sequence of statements to execute. If executing these +statements does not throw an exception, then the second operand is +ignored. Otherwise, if an exception is thrown, then the second operand +of the `GIMPLE_TRY_CATCH' is checked. The second operand may have the +following forms: + + 1. A sequence of statements to execute. When an exception occurs, + these statements are executed, and then the exception is rethrown. + + 2. A sequence of `GIMPLE_CATCH' statements. Each `GIMPLE_CATCH' has + a list of applicable exception types and handler code. If the + thrown exception matches one of the caught types, the associated + handler code is executed. If the handler code falls off the + bottom, execution continues after the original `GIMPLE_TRY_CATCH'. + + 3. A `GIMPLE_EH_FILTER' statement. This has a list of permitted + exception types, and code to handle a match failure. If the + thrown exception does not match one of the allowed types, the + associated match failure code is executed. If the thrown exception + does match, it continues unwinding the stack looking for the next + handler. + + + Currently throwing an exception is not directly represented in GIMPLE, +since it is implemented by calling a function. At some point in the +future we will want to add some way to express that the call will throw +an exception of a known type. + + Just before running the optimizers, the compiler lowers the high-level +EH constructs above into a set of `goto's, magic labels, and EH +regions. Continuing to unwind at the end of a cleanup is represented +with a `GIMPLE_RESX'. + + +File: gccint.info, Node: Temporaries, Next: Operands, Prev: GIMPLE Exception Handling, Up: GIMPLE + +12.4 Temporaries +================ + +When gimplification encounters a subexpression that is too complex, it +creates a new temporary variable to hold the value of the +subexpression, and adds a new statement to initialize it before the +current statement. These special temporaries are known as `expression +temporaries', and are allocated using `get_formal_tmp_var'. The +compiler tries to always evaluate identical expressions into the same +temporary, to simplify elimination of redundant calculations. + + We can only use expression temporaries when we know that it will not +be reevaluated before its value is used, and that it will not be +otherwise modified(1). Other temporaries can be allocated using +`get_initialized_tmp_var' or `create_tmp_var'. + + Currently, an expression like `a = b + 5' is not reduced any further. +We tried converting it to something like + T1 = b + 5; + a = T1; + but this bloated the representation for minimal benefit. However, a +variable which must live in memory cannot appear in an expression; its +value is explicitly loaded into a temporary first. Similarly, storing +the value of an expression to a memory variable goes through a +temporary. + + ---------- Footnotes ---------- + + (1) These restrictions are derived from those in Morgan 4.8. + + +File: gccint.info, Node: Operands, Next: Manipulating GIMPLE statements, Prev: Temporaries, Up: GIMPLE + +12.5 Operands +============= + +In general, expressions in GIMPLE consist of an operation and the +appropriate number of simple operands; these operands must either be a +GIMPLE rvalue (`is_gimple_val'), i.e. a constant or a register +variable. More complex operands are factored out into temporaries, so +that + a = b + c + d + becomes + T1 = b + c; + a = T1 + d; + + The same rule holds for arguments to a `GIMPLE_CALL'. + + The target of an assignment is usually a variable, but can also be a +`MEM_REF' or a compound lvalue as described below. + +* Menu: + +* Compound Expressions:: +* Compound Lvalues:: +* Conditional Expressions:: +* Logical Operators:: + + +File: gccint.info, Node: Compound Expressions, Next: Compound Lvalues, Up: Operands + +12.5.1 Compound Expressions +--------------------------- + +The left-hand side of a C comma expression is simply moved into a +separate statement. + + +File: gccint.info, Node: Compound Lvalues, Next: Conditional Expressions, Prev: Compound Expressions, Up: Operands + +12.5.2 Compound Lvalues +----------------------- + +Currently compound lvalues involving array and structure field +references are not broken down; an expression like `a.b[2] = 42' is not +reduced any further (though complex array subscripts are). This +restriction is a workaround for limitations in later optimizers; if we +were to convert this to + + T1 = &a.b; + T1[2] = 42; + + alias analysis would not remember that the reference to `T1[2]' came +by way of `a.b', so it would think that the assignment could alias +another member of `a'; this broke `struct-alias-1.c'. Future optimizer +improvements may make this limitation unnecessary. + + +File: gccint.info, Node: Conditional Expressions, Next: Logical Operators, Prev: Compound Lvalues, Up: Operands + +12.5.3 Conditional Expressions +------------------------------ + +A C `?:' expression is converted into an `if' statement with each +branch assigning to the same temporary. So, + + a = b ? c : d; + becomes + if (b == 1) + T1 = c; + else + T1 = d; + a = T1; + + The GIMPLE level if-conversion pass re-introduces `?:' expression, if +appropriate. It is used to vectorize loops with conditions using vector +conditional operations. + + Note that in GIMPLE, `if' statements are represented using +`GIMPLE_COND', as described below. + + +File: gccint.info, Node: Logical Operators, Prev: Conditional Expressions, Up: Operands + +12.5.4 Logical Operators +------------------------ + +Except when they appear in the condition operand of a `GIMPLE_COND', +logical `and' and `or' operators are simplified as follows: `a = b && +c' becomes + + T1 = (bool)b; + if (T1 == true) + T1 = (bool)c; + a = T1; + + Note that `T1' in this example cannot be an expression temporary, +because it has two different assignments. + +12.5.5 Manipulating operands +---------------------------- + +All gimple operands are of type `tree'. But only certain types of +trees are allowed to be used as operand tuples. Basic validation is +controlled by the function `get_gimple_rhs_class', which given a tree +code, returns an `enum' with the following values of type `enum +gimple_rhs_class' + + * `GIMPLE_INVALID_RHS' The tree cannot be used as a GIMPLE operand. + + * `GIMPLE_TERNARY_RHS' The tree is a valid GIMPLE ternary operation. + + * `GIMPLE_BINARY_RHS' The tree is a valid GIMPLE binary operation. + + * `GIMPLE_UNARY_RHS' The tree is a valid GIMPLE unary operation. + + * `GIMPLE_SINGLE_RHS' The tree is a single object, that cannot be + split into simpler operands (for instance, `SSA_NAME', `VAR_DECL', + `COMPONENT_REF', etc). + + This operand class also acts as an escape hatch for tree nodes + that may be flattened out into the operand vector, but would need + more than two slots on the RHS. For instance, a `COND_EXPR' + expression of the form `(a op b) ? x : y' could be flattened out + on the operand vector using 4 slots, but it would also require + additional processing to distinguish `c = a op b' from `c = a op b + ? x : y'. Something similar occurs with `ASSERT_EXPR'. In time, + these special case tree expressions should be flattened into the + operand vector. + + For tree nodes in the categories `GIMPLE_TERNARY_RHS', +`GIMPLE_BINARY_RHS' and `GIMPLE_UNARY_RHS', they cannot be stored +inside tuples directly. They first need to be flattened and separated +into individual components. For instance, given the GENERIC expression + + a = b + c + + its tree representation is: + + MODIFY_EXPR <VAR_DECL <a>, PLUS_EXPR <VAR_DECL <b>, VAR_DECL <c>>> + + In this case, the GIMPLE form for this statement is logically +identical to its GENERIC form but in GIMPLE, the `PLUS_EXPR' on the RHS +of the assignment is not represented as a tree, instead the two +operands are taken out of the `PLUS_EXPR' sub-tree and flattened into +the GIMPLE tuple as follows: + + GIMPLE_ASSIGN <PLUS_EXPR, VAR_DECL <a>, VAR_DECL <b>, VAR_DECL <c>> + +12.5.6 Operand vector allocation +-------------------------------- + +The operand vector is stored at the bottom of the three tuple +structures that accept operands. This means, that depending on the code +of a given statement, its operand vector will be at different offsets +from the base of the structure. To access tuple operands use the +following accessors + + -- GIMPLE function: unsigned gimple_num_ops (gimple g) + Returns the number of operands in statement G. + + -- GIMPLE function: tree gimple_op (gimple g, unsigned i) + Returns operand `I' from statement `G'. + + -- GIMPLE function: tree * gimple_ops (gimple g) + Returns a pointer into the operand vector for statement `G'. This + is computed using an internal table called `gimple_ops_offset_'[]. + This table is indexed by the gimple code of `G'. + + When the compiler is built, this table is filled-in using the + sizes of the structures used by each statement code defined in + gimple.def. Since the operand vector is at the bottom of the + structure, for a gimple code `C' the offset is computed as sizeof + (struct-of `C') - sizeof (tree). + + This mechanism adds one memory indirection to every access when + using `gimple_op'(), if this becomes a bottleneck, a pass can + choose to memoize the result from `gimple_ops'() and use that to + access the operands. + +12.5.7 Operand validation +------------------------- + +When adding a new operand to a gimple statement, the operand will be +validated according to what each tuple accepts in its operand vector. +These predicates are called by the `gimple_NAME_set_...()'. Each tuple +will use one of the following predicates (Note, this list is not +exhaustive): + + -- GIMPLE function: bool is_gimple_val (tree t) + Returns true if t is a "GIMPLE value", which are all the + non-addressable stack variables (variables for which + `is_gimple_reg' returns true) and constants (expressions for which + `is_gimple_min_invariant' returns true). + + -- GIMPLE function: bool is_gimple_addressable (tree t) + Returns true if t is a symbol or memory reference whose address + can be taken. + + -- GIMPLE function: bool is_gimple_asm_val (tree t) + Similar to `is_gimple_val' but it also accepts hard registers. + + -- GIMPLE function: bool is_gimple_call_addr (tree t) + Return true if t is a valid expression to use as the function + called by a `GIMPLE_CALL'. + + -- GIMPLE function: bool is_gimple_mem_ref_addr (tree t) + Return true if t is a valid expression to use as first operand of + a `MEM_REF' expression. + + -- GIMPLE function: bool is_gimple_constant (tree t) + Return true if t is a valid gimple constant. + + -- GIMPLE function: bool is_gimple_min_invariant (tree t) + Return true if t is a valid minimal invariant. This is different + from constants, in that the specific value of t may not be known + at compile time, but it is known that it doesn't change (e.g., the + address of a function local variable). + + -- GIMPLE function: bool is_gimple_ip_invariant (tree t) + Return true if t is an interprocedural invariant. This means that + t is a valid invariant in all functions (e.g. it can be an address + of a global variable but not of a local one). + + -- GIMPLE function: bool is_gimple_ip_invariant_address (tree t) + Return true if t is an `ADDR_EXPR' that does not change once the + program is running (and which is valid in all functions). + +12.5.8 Statement validation +--------------------------- + + -- GIMPLE function: bool is_gimple_assign (gimple g) + Return true if the code of g is `GIMPLE_ASSIGN'. + + -- GIMPLE function: bool is_gimple_call (gimple g) + Return true if the code of g is `GIMPLE_CALL'. + + -- GIMPLE function: bool is_gimple_debug (gimple g) + Return true if the code of g is `GIMPLE_DEBUG'. + + -- GIMPLE function: bool gimple_assign_cast_p (gimple g) + Return true if g is a `GIMPLE_ASSIGN' that performs a type cast + operation. + + -- GIMPLE function: bool gimple_debug_bind_p (gimple g) + Return true if g is a `GIMPLE_DEBUG' that binds the value of an + expression to a variable. + + +File: gccint.info, Node: Manipulating GIMPLE statements, Next: Tuple specific accessors, Prev: Operands, Up: GIMPLE + +12.6 Manipulating GIMPLE statements +=================================== + +This section documents all the functions available to handle each of +the GIMPLE instructions. + +12.6.1 Common accessors +----------------------- + +The following are common accessors for gimple statements. + + -- GIMPLE function: enum gimple_code gimple_code (gimple g) + Return the code for statement `G'. + + -- GIMPLE function: basic_block gimple_bb (gimple g) + Return the basic block to which statement `G' belongs to. + + -- GIMPLE function: tree gimple_block (gimple g) + Return the lexical scope block holding statement `G'. + + -- GIMPLE function: tree gimple_expr_type (gimple stmt) + Return the type of the main expression computed by `STMT'. Return + `void_type_node' if `STMT' computes nothing. This will only return + something meaningful for `GIMPLE_ASSIGN', `GIMPLE_COND' and + `GIMPLE_CALL'. For all other tuple codes, it will return + `void_type_node'. + + -- GIMPLE function: enum tree_code gimple_expr_code (gimple stmt) + Return the tree code for the expression computed by `STMT'. This + is only meaningful for `GIMPLE_CALL', `GIMPLE_ASSIGN' and + `GIMPLE_COND'. If `STMT' is `GIMPLE_CALL', it will return + `CALL_EXPR'. For `GIMPLE_COND', it returns the code of the + comparison predicate. For `GIMPLE_ASSIGN' it returns the code of + the operation performed by the `RHS' of the assignment. + + -- GIMPLE function: void gimple_set_block (gimple g, tree block) + Set the lexical scope block of `G' to `BLOCK'. + + -- GIMPLE function: location_t gimple_locus (gimple g) + Return locus information for statement `G'. + + -- GIMPLE function: void gimple_set_locus (gimple g, location_t locus) + Set locus information for statement `G'. + + -- GIMPLE function: bool gimple_locus_empty_p (gimple g) + Return true if `G' does not have locus information. + + -- GIMPLE function: bool gimple_no_warning_p (gimple stmt) + Return true if no warnings should be emitted for statement `STMT'. + + -- GIMPLE function: void gimple_set_visited (gimple stmt, bool + visited_p) + Set the visited status on statement `STMT' to `VISITED_P'. + + -- GIMPLE function: bool gimple_visited_p (gimple stmt) + Return the visited status on statement `STMT'. + + -- GIMPLE function: void gimple_set_plf (gimple stmt, enum plf_mask + plf, bool val_p) + Set pass local flag `PLF' on statement `STMT' to `VAL_P'. + + -- GIMPLE function: unsigned int gimple_plf (gimple stmt, enum + plf_mask plf) + Return the value of pass local flag `PLF' on statement `STMT'. + + -- GIMPLE function: bool gimple_has_ops (gimple g) + Return true if statement `G' has register or memory operands. + + -- GIMPLE function: bool gimple_has_mem_ops (gimple g) + Return true if statement `G' has memory operands. + + -- GIMPLE function: unsigned gimple_num_ops (gimple g) + Return the number of operands for statement `G'. + + -- GIMPLE function: tree * gimple_ops (gimple g) + Return the array of operands for statement `G'. + + -- GIMPLE function: tree gimple_op (gimple g, unsigned i) + Return operand `I' for statement `G'. + + -- GIMPLE function: tree * gimple_op_ptr (gimple g, unsigned i) + Return a pointer to operand `I' for statement `G'. + + -- GIMPLE function: void gimple_set_op (gimple g, unsigned i, tree op) + Set operand `I' of statement `G' to `OP'. + + -- GIMPLE function: bitmap gimple_addresses_taken (gimple stmt) + Return the set of symbols that have had their address taken by + `STMT'. + + -- GIMPLE function: struct def_optype_d * gimple_def_ops (gimple g) + Return the set of `DEF' operands for statement `G'. + + -- GIMPLE function: void gimple_set_def_ops (gimple g, struct + def_optype_d *def) + Set `DEF' to be the set of `DEF' operands for statement `G'. + + -- GIMPLE function: struct use_optype_d * gimple_use_ops (gimple g) + Return the set of `USE' operands for statement `G'. + + -- GIMPLE function: void gimple_set_use_ops (gimple g, struct + use_optype_d *use) + Set `USE' to be the set of `USE' operands for statement `G'. + + -- GIMPLE function: struct voptype_d * gimple_vuse_ops (gimple g) + Return the set of `VUSE' operands for statement `G'. + + -- GIMPLE function: void gimple_set_vuse_ops (gimple g, struct + voptype_d *ops) + Set `OPS' to be the set of `VUSE' operands for statement `G'. + + -- GIMPLE function: struct voptype_d * gimple_vdef_ops (gimple g) + Return the set of `VDEF' operands for statement `G'. + + -- GIMPLE function: void gimple_set_vdef_ops (gimple g, struct + voptype_d *ops) + Set `OPS' to be the set of `VDEF' operands for statement `G'. + + -- GIMPLE function: bitmap gimple_loaded_syms (gimple g) + Return the set of symbols loaded by statement `G'. Each element of + the set is the `DECL_UID' of the corresponding symbol. + + -- GIMPLE function: bitmap gimple_stored_syms (gimple g) + Return the set of symbols stored by statement `G'. Each element of + the set is the `DECL_UID' of the corresponding symbol. + + -- GIMPLE function: bool gimple_modified_p (gimple g) + Return true if statement `G' has operands and the modified field + has been set. + + -- GIMPLE function: bool gimple_has_volatile_ops (gimple stmt) + Return true if statement `STMT' contains volatile operands. + + -- GIMPLE function: void gimple_set_has_volatile_ops (gimple stmt, + bool volatilep) + Return true if statement `STMT' contains volatile operands. + + -- GIMPLE function: void update_stmt (gimple s) + Mark statement `S' as modified, and update it. + + -- GIMPLE function: void update_stmt_if_modified (gimple s) + Update statement `S' if it has been marked modified. + + -- GIMPLE function: gimple gimple_copy (gimple stmt) + Return a deep copy of statement `STMT'. + + +File: gccint.info, Node: Tuple specific accessors, Next: GIMPLE sequences, Prev: Manipulating GIMPLE statements, Up: GIMPLE + +12.7 Tuple specific accessors +============================= + +* Menu: + +* `GIMPLE_ASM':: +* `GIMPLE_ASSIGN':: +* `GIMPLE_BIND':: +* `GIMPLE_CALL':: +* `GIMPLE_CATCH':: +* `GIMPLE_COND':: +* `GIMPLE_DEBUG':: +* `GIMPLE_EH_FILTER':: +* `GIMPLE_LABEL':: +* `GIMPLE_NOP':: +* `GIMPLE_OMP_ATOMIC_LOAD':: +* `GIMPLE_OMP_ATOMIC_STORE':: +* `GIMPLE_OMP_CONTINUE':: +* `GIMPLE_OMP_CRITICAL':: +* `GIMPLE_OMP_FOR':: +* `GIMPLE_OMP_MASTER':: +* `GIMPLE_OMP_ORDERED':: +* `GIMPLE_OMP_PARALLEL':: +* `GIMPLE_OMP_RETURN':: +* `GIMPLE_OMP_SECTION':: +* `GIMPLE_OMP_SECTIONS':: +* `GIMPLE_OMP_SINGLE':: +* `GIMPLE_PHI':: +* `GIMPLE_RESX':: +* `GIMPLE_RETURN':: +* `GIMPLE_SWITCH':: +* `GIMPLE_TRY':: +* `GIMPLE_WITH_CLEANUP_EXPR':: + + +File: gccint.info, Node: `GIMPLE_ASM', Next: `GIMPLE_ASSIGN', Up: Tuple specific accessors + +12.7.1 `GIMPLE_ASM' +------------------- + + -- GIMPLE function: gimple gimple_build_asm (const char *string, + ninputs, noutputs, nclobbers, ...) + Build a `GIMPLE_ASM' statement. This statement is used for + building in-line assembly constructs. `STRING' is the assembly + code. `NINPUT' is the number of register inputs. `NOUTPUT' is the + number of register outputs. `NCLOBBERS' is the number of clobbered + registers. The rest of the arguments trees for each input, + output, and clobbered registers. + + -- GIMPLE function: gimple gimple_build_asm_vec (const char *, + VEC(tree,gc) *, VEC(tree,gc) *, VEC(tree,gc) *) + Identical to gimple_build_asm, but the arguments are passed in + VECs. + + -- GIMPLE function: unsigned gimple_asm_ninputs (gimple g) + Return the number of input operands for `GIMPLE_ASM' `G'. + + -- GIMPLE function: unsigned gimple_asm_noutputs (gimple g) + Return the number of output operands for `GIMPLE_ASM' `G'. + + -- GIMPLE function: unsigned gimple_asm_nclobbers (gimple g) + Return the number of clobber operands for `GIMPLE_ASM' `G'. + + -- GIMPLE function: tree gimple_asm_input_op (gimple g, unsigned index) + Return input operand `INDEX' of `GIMPLE_ASM' `G'. + + -- GIMPLE function: void gimple_asm_set_input_op (gimple g, unsigned + index, tree in_op) + Set `IN_OP' to be input operand `INDEX' in `GIMPLE_ASM' `G'. + + -- GIMPLE function: tree gimple_asm_output_op (gimple g, unsigned + index) + Return output operand `INDEX' of `GIMPLE_ASM' `G'. + + -- GIMPLE function: void gimple_asm_set_output_op (gimple g, unsigned + index, tree out_op) + Set `OUT_OP' to be output operand `INDEX' in `GIMPLE_ASM' `G'. + + -- GIMPLE function: tree gimple_asm_clobber_op (gimple g, unsigned + index) + Return clobber operand `INDEX' of `GIMPLE_ASM' `G'. + + -- GIMPLE function: void gimple_asm_set_clobber_op (gimple g, unsigned + index, tree clobber_op) + Set `CLOBBER_OP' to be clobber operand `INDEX' in `GIMPLE_ASM' `G'. + + -- GIMPLE function: const char * gimple_asm_string (gimple g) + Return the string representing the assembly instruction in + `GIMPLE_ASM' `G'. + + -- GIMPLE function: bool gimple_asm_volatile_p (gimple g) + Return true if `G' is an asm statement marked volatile. + + -- GIMPLE function: void gimple_asm_set_volatile (gimple g) + Mark asm statement `G' as volatile. + + -- GIMPLE function: void gimple_asm_clear_volatile (gimple g) + Remove volatile marker from asm statement `G'. + + +File: gccint.info, Node: `GIMPLE_ASSIGN', Next: `GIMPLE_BIND', Prev: `GIMPLE_ASM', Up: Tuple specific accessors + +12.7.2 `GIMPLE_ASSIGN' +---------------------- + + -- GIMPLE function: gimple gimple_build_assign (tree lhs, tree rhs) + Build a `GIMPLE_ASSIGN' statement. The left-hand side is an lvalue + passed in lhs. The right-hand side can be either a unary or + binary tree expression. The expression tree rhs will be flattened + and its operands assigned to the corresponding operand slots in + the new statement. This function is useful when you already have + a tree expression that you want to convert into a tuple. However, + try to avoid building expression trees for the sole purpose of + calling this function. If you already have the operands in + separate trees, it is better to use `gimple_build_assign_with_ops'. + + -- GIMPLE function: gimple gimplify_assign (tree dst, tree src, + gimple_seq *seq_p) + Build a new `GIMPLE_ASSIGN' tuple and append it to the end of + `*SEQ_P'. + + `DST'/`SRC' are the destination and source respectively. You can pass +ungimplified trees in `DST' or `SRC', in which case they will be +converted to a gimple operand if necessary. + + This function returns the newly created `GIMPLE_ASSIGN' tuple. + + -- GIMPLE function: gimple gimple_build_assign_with_ops (enum + tree_code subcode, tree lhs, tree op1, tree op2) + This function is similar to `gimple_build_assign', but is used to + build a `GIMPLE_ASSIGN' statement when the operands of the + right-hand side of the assignment are already split into different + operands. + + The left-hand side is an lvalue passed in lhs. Subcode is the + `tree_code' for the right-hand side of the assignment. Op1 and op2 + are the operands. If op2 is null, subcode must be a `tree_code' + for a unary expression. + + -- GIMPLE function: enum tree_code gimple_assign_rhs_code (gimple g) + Return the code of the expression computed on the `RHS' of + assignment statement `G'. + + -- GIMPLE function: enum gimple_rhs_class gimple_assign_rhs_class + (gimple g) + Return the gimple rhs class of the code for the expression + computed on the rhs of assignment statement `G'. This will never + return `GIMPLE_INVALID_RHS'. + + -- GIMPLE function: tree gimple_assign_lhs (gimple g) + Return the `LHS' of assignment statement `G'. + + -- GIMPLE function: tree * gimple_assign_lhs_ptr (gimple g) + Return a pointer to the `LHS' of assignment statement `G'. + + -- GIMPLE function: tree gimple_assign_rhs1 (gimple g) + Return the first operand on the `RHS' of assignment statement `G'. + + -- GIMPLE function: tree * gimple_assign_rhs1_ptr (gimple g) + Return the address of the first operand on the `RHS' of assignment + statement `G'. + + -- GIMPLE function: tree gimple_assign_rhs2 (gimple g) + Return the second operand on the `RHS' of assignment statement `G'. + + -- GIMPLE function: tree * gimple_assign_rhs2_ptr (gimple g) + Return the address of the second operand on the `RHS' of assignment + statement `G'. + + -- GIMPLE function: tree gimple_assign_rhs3 (gimple g) + Return the third operand on the `RHS' of assignment statement `G'. + + -- GIMPLE function: tree * gimple_assign_rhs3_ptr (gimple g) + Return the address of the third operand on the `RHS' of assignment + statement `G'. + + -- GIMPLE function: void gimple_assign_set_lhs (gimple g, tree lhs) + Set `LHS' to be the `LHS' operand of assignment statement `G'. + + -- GIMPLE function: void gimple_assign_set_rhs1 (gimple g, tree rhs) + Set `RHS' to be the first operand on the `RHS' of assignment + statement `G'. + + -- GIMPLE function: void gimple_assign_set_rhs2 (gimple g, tree rhs) + Set `RHS' to be the second operand on the `RHS' of assignment + statement `G'. + + -- GIMPLE function: void gimple_assign_set_rhs3 (gimple g, tree rhs) + Set `RHS' to be the third operand on the `RHS' of assignment + statement `G'. + + -- GIMPLE function: bool gimple_assign_cast_p (gimple s) + Return true if `S' is a type-cast assignment. + + +File: gccint.info, Node: `GIMPLE_BIND', Next: `GIMPLE_CALL', Prev: `GIMPLE_ASSIGN', Up: Tuple specific accessors + +12.7.3 `GIMPLE_BIND' +-------------------- + + -- GIMPLE function: gimple gimple_build_bind (tree vars, gimple_seq + body) + Build a `GIMPLE_BIND' statement with a list of variables in `VARS' + and a body of statements in sequence `BODY'. + + -- GIMPLE function: tree gimple_bind_vars (gimple g) + Return the variables declared in the `GIMPLE_BIND' statement `G'. + + -- GIMPLE function: void gimple_bind_set_vars (gimple g, tree vars) + Set `VARS' to be the set of variables declared in the `GIMPLE_BIND' + statement `G'. + + -- GIMPLE function: void gimple_bind_append_vars (gimple g, tree vars) + Append `VARS' to the set of variables declared in the `GIMPLE_BIND' + statement `G'. + + -- GIMPLE function: gimple_seq gimple_bind_body (gimple g) + Return the GIMPLE sequence contained in the `GIMPLE_BIND' statement + `G'. + + -- GIMPLE function: void gimple_bind_set_body (gimple g, gimple_seq + seq) + Set `SEQ' to be sequence contained in the `GIMPLE_BIND' statement + `G'. + + -- GIMPLE function: void gimple_bind_add_stmt (gimple gs, gimple stmt) + Append a statement to the end of a `GIMPLE_BIND''s body. + + -- GIMPLE function: void gimple_bind_add_seq (gimple gs, gimple_seq + seq) + Append a sequence of statements to the end of a `GIMPLE_BIND''s + body. + + -- GIMPLE function: tree gimple_bind_block (gimple g) + Return the `TREE_BLOCK' node associated with `GIMPLE_BIND' + statement `G'. This is analogous to the `BIND_EXPR_BLOCK' field in + trees. + + -- GIMPLE function: void gimple_bind_set_block (gimple g, tree block) + Set `BLOCK' to be the `TREE_BLOCK' node associated with + `GIMPLE_BIND' statement `G'. + + +File: gccint.info, Node: `GIMPLE_CALL', Next: `GIMPLE_CATCH', Prev: `GIMPLE_BIND', Up: Tuple specific accessors + +12.7.4 `GIMPLE_CALL' +-------------------- + + -- GIMPLE function: gimple gimple_build_call (tree fn, unsigned nargs, + ...) + Build a `GIMPLE_CALL' statement to function `FN'. The argument + `FN' must be either a `FUNCTION_DECL' or a gimple call address as + determined by `is_gimple_call_addr'. `NARGS' are the number of + arguments. The rest of the arguments follow the argument `NARGS', + and must be trees that are valid as rvalues in gimple (i.e., each + operand is validated with `is_gimple_operand'). + + -- GIMPLE function: gimple gimple_build_call_from_tree (tree call_expr) + Build a `GIMPLE_CALL' from a `CALL_EXPR' node. The arguments and + the function are taken from the expression directly. This routine + assumes that `call_expr' is already in GIMPLE form. That is, its + operands are GIMPLE values and the function call needs no further + simplification. All the call flags in `call_expr' are copied over + to the new `GIMPLE_CALL'. + + -- GIMPLE function: gimple gimple_build_call_vec (tree fn, `VEC'(tree, + heap) *args) + Identical to `gimple_build_call' but the arguments are stored in a + `VEC'(). + + -- GIMPLE function: tree gimple_call_lhs (gimple g) + Return the `LHS' of call statement `G'. + + -- GIMPLE function: tree * gimple_call_lhs_ptr (gimple g) + Return a pointer to the `LHS' of call statement `G'. + + -- GIMPLE function: void gimple_call_set_lhs (gimple g, tree lhs) + Set `LHS' to be the `LHS' operand of call statement `G'. + + -- GIMPLE function: tree gimple_call_fn (gimple g) + Return the tree node representing the function called by call + statement `G'. + + -- GIMPLE function: void gimple_call_set_fn (gimple g, tree fn) + Set `FN' to be the function called by call statement `G'. This has + to be a gimple value specifying the address of the called function. + + -- GIMPLE function: tree gimple_call_fndecl (gimple g) + If a given `GIMPLE_CALL''s callee is a `FUNCTION_DECL', return it. + Otherwise return `NULL'. This function is analogous to + `get_callee_fndecl' in `GENERIC'. + + -- GIMPLE function: tree gimple_call_set_fndecl (gimple g, tree fndecl) + Set the called function to `FNDECL'. + + -- GIMPLE function: tree gimple_call_return_type (gimple g) + Return the type returned by call statement `G'. + + -- GIMPLE function: tree gimple_call_chain (gimple g) + Return the static chain for call statement `G'. + + -- GIMPLE function: void gimple_call_set_chain (gimple g, tree chain) + Set `CHAIN' to be the static chain for call statement `G'. + + -- GIMPLE function: unsigned gimple_call_num_args (gimple g) + Return the number of arguments used by call statement `G'. + + -- GIMPLE function: tree gimple_call_arg (gimple g, unsigned index) + Return the argument at position `INDEX' for call statement `G'. + The first argument is 0. + + -- GIMPLE function: tree * gimple_call_arg_ptr (gimple g, unsigned + index) + Return a pointer to the argument at position `INDEX' for call + statement `G'. + + -- GIMPLE function: void gimple_call_set_arg (gimple g, unsigned + index, tree arg) + Set `ARG' to be the argument at position `INDEX' for call statement + `G'. + + -- GIMPLE function: void gimple_call_set_tail (gimple s) + Mark call statement `S' as being a tail call (i.e., a call just + before the exit of a function). These calls are candidate for tail + call optimization. + + -- GIMPLE function: bool gimple_call_tail_p (gimple s) + Return true if `GIMPLE_CALL' `S' is marked as a tail call. + + -- GIMPLE function: void gimple_call_mark_uninlinable (gimple s) + Mark `GIMPLE_CALL' `S' as being uninlinable. + + -- GIMPLE function: bool gimple_call_cannot_inline_p (gimple s) + Return true if `GIMPLE_CALL' `S' cannot be inlined. + + -- GIMPLE function: bool gimple_call_noreturn_p (gimple s) + Return true if `S' is a noreturn call. + + -- GIMPLE function: gimple gimple_call_copy_skip_args (gimple stmt, + bitmap args_to_skip) + Build a `GIMPLE_CALL' identical to `STMT' but skipping the + arguments in the positions marked by the set `ARGS_TO_SKIP'. + + +File: gccint.info, Node: `GIMPLE_CATCH', Next: `GIMPLE_COND', Prev: `GIMPLE_CALL', Up: Tuple specific accessors + +12.7.5 `GIMPLE_CATCH' +--------------------- + + -- GIMPLE function: gimple gimple_build_catch (tree types, gimple_seq + handler) + Build a `GIMPLE_CATCH' statement. `TYPES' are the tree types this + catch handles. `HANDLER' is a sequence of statements with the code + for the handler. + + -- GIMPLE function: tree gimple_catch_types (gimple g) + Return the types handled by `GIMPLE_CATCH' statement `G'. + + -- GIMPLE function: tree * gimple_catch_types_ptr (gimple g) + Return a pointer to the types handled by `GIMPLE_CATCH' statement + `G'. + + -- GIMPLE function: gimple_seq gimple_catch_handler (gimple g) + Return the GIMPLE sequence representing the body of the handler of + `GIMPLE_CATCH' statement `G'. + + -- GIMPLE function: void gimple_catch_set_types (gimple g, tree t) + Set `T' to be the set of types handled by `GIMPLE_CATCH' `G'. + + -- GIMPLE function: void gimple_catch_set_handler (gimple g, + gimple_seq handler) + Set `HANDLER' to be the body of `GIMPLE_CATCH' `G'. + + +File: gccint.info, Node: `GIMPLE_COND', Next: `GIMPLE_DEBUG', Prev: `GIMPLE_CATCH', Up: Tuple specific accessors + +12.7.6 `GIMPLE_COND' +-------------------- + + -- GIMPLE function: gimple gimple_build_cond (enum tree_code + pred_code, tree lhs, tree rhs, tree t_label, tree f_label) + Build a `GIMPLE_COND' statement. `A' `GIMPLE_COND' statement + compares `LHS' and `RHS' and if the condition in `PRED_CODE' is + true, jump to the label in `t_label', otherwise jump to the label + in `f_label'. `PRED_CODE' are relational operator tree codes like + `EQ_EXPR', `LT_EXPR', `LE_EXPR', `NE_EXPR', etc. + + -- GIMPLE function: gimple gimple_build_cond_from_tree (tree cond, + tree t_label, tree f_label) + Build a `GIMPLE_COND' statement from the conditional expression + tree `COND'. `T_LABEL' and `F_LABEL' are as in + `gimple_build_cond'. + + -- GIMPLE function: enum tree_code gimple_cond_code (gimple g) + Return the code of the predicate computed by conditional statement + `G'. + + -- GIMPLE function: void gimple_cond_set_code (gimple g, enum + tree_code code) + Set `CODE' to be the predicate code for the conditional statement + `G'. + + -- GIMPLE function: tree gimple_cond_lhs (gimple g) + Return the `LHS' of the predicate computed by conditional statement + `G'. + + -- GIMPLE function: void gimple_cond_set_lhs (gimple g, tree lhs) + Set `LHS' to be the `LHS' operand of the predicate computed by + conditional statement `G'. + + -- GIMPLE function: tree gimple_cond_rhs (gimple g) + Return the `RHS' operand of the predicate computed by conditional + `G'. + + -- GIMPLE function: void gimple_cond_set_rhs (gimple g, tree rhs) + Set `RHS' to be the `RHS' operand of the predicate computed by + conditional statement `G'. + + -- GIMPLE function: tree gimple_cond_true_label (gimple g) + Return the label used by conditional statement `G' when its + predicate evaluates to true. + + -- GIMPLE function: void gimple_cond_set_true_label (gimple g, tree + label) + Set `LABEL' to be the label used by conditional statement `G' when + its predicate evaluates to true. + + -- GIMPLE function: void gimple_cond_set_false_label (gimple g, tree + label) + Set `LABEL' to be the label used by conditional statement `G' when + its predicate evaluates to false. + + -- GIMPLE function: tree gimple_cond_false_label (gimple g) + Return the label used by conditional statement `G' when its + predicate evaluates to false. + + -- GIMPLE function: void gimple_cond_make_false (gimple g) + Set the conditional `COND_STMT' to be of the form 'if (1 == 0)'. + + -- GIMPLE function: void gimple_cond_make_true (gimple g) + Set the conditional `COND_STMT' to be of the form 'if (1 == 1)'. + + +File: gccint.info, Node: `GIMPLE_DEBUG', Next: `GIMPLE_EH_FILTER', Prev: `GIMPLE_COND', Up: Tuple specific accessors + +12.7.7 `GIMPLE_DEBUG' +--------------------- + + -- GIMPLE function: gimple gimple_build_debug_bind (tree var, tree + value, gimple stmt) + Build a `GIMPLE_DEBUG' statement with `GIMPLE_DEBUG_BIND' of + `subcode'. The effect of this statement is to tell debug + information generation machinery that the value of user variable + `var' is given by `value' at that point, and to remain with that + value until `var' runs out of scope, a dynamically-subsequent + debug bind statement overrides the binding, or conflicting values + reach a control flow merge point. Even if components of the + `value' expression change afterwards, the variable is supposed to + retain the same value, though not necessarily the same location. + + It is expected that `var' be most often a tree for automatic user + variables (`VAR_DECL' or `PARM_DECL') that satisfy the + requirements for gimple registers, but it may also be a tree for a + scalarized component of a user variable (`ARRAY_REF', + `COMPONENT_REF'), or a debug temporary (`DEBUG_EXPR_DECL'). + + As for `value', it can be an arbitrary tree expression, but it is + recommended that it be in a suitable form for a gimple assignment + `RHS'. It is not expected that user variables that could appear + as `var' ever appear in `value', because in the latter we'd have + their `SSA_NAME's instead, but even if they were not in SSA form, + user variables appearing in `value' are to be regarded as part of + the executable code space, whereas those in `var' are to be + regarded as part of the source code space. There is no way to + refer to the value bound to a user variable within a `value' + expression. + + If `value' is `GIMPLE_DEBUG_BIND_NOVALUE', debug information + generation machinery is informed that the variable `var' is + unbound, i.e., that its value is indeterminate, which sometimes + means it is really unavailable, and other times that the compiler + could not keep track of it. + + Block and location information for the newly-created stmt are + taken from `stmt', if given. + + -- GIMPLE function: tree gimple_debug_bind_get_var (gimple stmt) + Return the user variable VAR that is bound at `stmt'. + + -- GIMPLE function: tree gimple_debug_bind_get_value (gimple stmt) + Return the value expression that is bound to a user variable at + `stmt'. + + -- GIMPLE function: tree * gimple_debug_bind_get_value_ptr (gimple + stmt) + Return a pointer to the value expression that is bound to a user + variable at `stmt'. + + -- GIMPLE function: void gimple_debug_bind_set_var (gimple stmt, tree + var) + Modify the user variable bound at `stmt' to VAR. + + -- GIMPLE function: void gimple_debug_bind_set_value (gimple stmt, + tree var) + Modify the value bound to the user variable bound at `stmt' to + VALUE. + + -- GIMPLE function: void gimple_debug_bind_reset_value (gimple stmt) + Modify the value bound to the user variable bound at `stmt' so + that the variable becomes unbound. + + -- GIMPLE function: bool gimple_debug_bind_has_value_p (gimple stmt) + Return `TRUE' if `stmt' binds a user variable to a value, and + `FALSE' if it unbinds the variable. + + +File: gccint.info, Node: `GIMPLE_EH_FILTER', Next: `GIMPLE_LABEL', Prev: `GIMPLE_DEBUG', Up: Tuple specific accessors + +12.7.8 `GIMPLE_EH_FILTER' +------------------------- + + -- GIMPLE function: gimple gimple_build_eh_filter (tree types, + gimple_seq failure) + Build a `GIMPLE_EH_FILTER' statement. `TYPES' are the filter's + types. `FAILURE' is a sequence with the filter's failure action. + + -- GIMPLE function: tree gimple_eh_filter_types (gimple g) + Return the types handled by `GIMPLE_EH_FILTER' statement `G'. + + -- GIMPLE function: tree * gimple_eh_filter_types_ptr (gimple g) + Return a pointer to the types handled by `GIMPLE_EH_FILTER' + statement `G'. + + -- GIMPLE function: gimple_seq gimple_eh_filter_failure (gimple g) + Return the sequence of statement to execute when `GIMPLE_EH_FILTER' + statement fails. + + -- GIMPLE function: void gimple_eh_filter_set_types (gimple g, tree + types) + Set `TYPES' to be the set of types handled by `GIMPLE_EH_FILTER' + `G'. + + -- GIMPLE function: void gimple_eh_filter_set_failure (gimple g, + gimple_seq failure) + Set `FAILURE' to be the sequence of statements to execute on + failure for `GIMPLE_EH_FILTER' `G'. + + -- GIMPLE function: bool gimple_eh_filter_must_not_throw (gimple g) + Return the `EH_FILTER_MUST_NOT_THROW' flag. + + -- GIMPLE function: void gimple_eh_filter_set_must_not_throw (gimple + g, bool mntp) + Set the `EH_FILTER_MUST_NOT_THROW' flag. + + +File: gccint.info, Node: `GIMPLE_LABEL', Next: `GIMPLE_NOP', Prev: `GIMPLE_EH_FILTER', Up: Tuple specific accessors + +12.7.9 `GIMPLE_LABEL' +--------------------- + + -- GIMPLE function: gimple gimple_build_label (tree label) + Build a `GIMPLE_LABEL' statement with corresponding to the tree + label, `LABEL'. + + -- GIMPLE function: tree gimple_label_label (gimple g) + Return the `LABEL_DECL' node used by `GIMPLE_LABEL' statement `G'. + + -- GIMPLE function: void gimple_label_set_label (gimple g, tree label) + Set `LABEL' to be the `LABEL_DECL' node used by `GIMPLE_LABEL' + statement `G'. + + -- GIMPLE function: gimple gimple_build_goto (tree dest) + Build a `GIMPLE_GOTO' statement to label `DEST'. + + -- GIMPLE function: tree gimple_goto_dest (gimple g) + Return the destination of the unconditional jump `G'. + + -- GIMPLE function: void gimple_goto_set_dest (gimple g, tree dest) + Set `DEST' to be the destination of the unconditional jump `G'. + + +File: gccint.info, Node: `GIMPLE_NOP', Next: `GIMPLE_OMP_ATOMIC_LOAD', Prev: `GIMPLE_LABEL', Up: Tuple specific accessors + +12.7.10 `GIMPLE_NOP' +-------------------- + + -- GIMPLE function: gimple gimple_build_nop (void) + Build a `GIMPLE_NOP' statement. + + -- GIMPLE function: bool gimple_nop_p (gimple g) + Returns `TRUE' if statement `G' is a `GIMPLE_NOP'. + + +File: gccint.info, Node: `GIMPLE_OMP_ATOMIC_LOAD', Next: `GIMPLE_OMP_ATOMIC_STORE', Prev: `GIMPLE_NOP', Up: Tuple specific accessors + +12.7.11 `GIMPLE_OMP_ATOMIC_LOAD' +-------------------------------- + + -- GIMPLE function: gimple gimple_build_omp_atomic_load (tree lhs, + tree rhs) + Build a `GIMPLE_OMP_ATOMIC_LOAD' statement. `LHS' is the left-hand + side of the assignment. `RHS' is the right-hand side of the + assignment. + + -- GIMPLE function: void gimple_omp_atomic_load_set_lhs (gimple g, + tree lhs) + Set the `LHS' of an atomic load. + + -- GIMPLE function: tree gimple_omp_atomic_load_lhs (gimple g) + Get the `LHS' of an atomic load. + + -- GIMPLE function: void gimple_omp_atomic_load_set_rhs (gimple g, + tree rhs) + Set the `RHS' of an atomic set. + + -- GIMPLE function: tree gimple_omp_atomic_load_rhs (gimple g) + Get the `RHS' of an atomic set. + + +File: gccint.info, Node: `GIMPLE_OMP_ATOMIC_STORE', Next: `GIMPLE_OMP_CONTINUE', Prev: `GIMPLE_OMP_ATOMIC_LOAD', Up: Tuple specific accessors + +12.7.12 `GIMPLE_OMP_ATOMIC_STORE' +--------------------------------- + + -- GIMPLE function: gimple gimple_build_omp_atomic_store (tree val) + Build a `GIMPLE_OMP_ATOMIC_STORE' statement. `VAL' is the value to + be stored. + + -- GIMPLE function: void gimple_omp_atomic_store_set_val (gimple g, + tree val) + Set the value being stored in an atomic store. + + -- GIMPLE function: tree gimple_omp_atomic_store_val (gimple g) + Return the value being stored in an atomic store. + + +File: gccint.info, Node: `GIMPLE_OMP_CONTINUE', Next: `GIMPLE_OMP_CRITICAL', Prev: `GIMPLE_OMP_ATOMIC_STORE', Up: Tuple specific accessors + +12.7.13 `GIMPLE_OMP_CONTINUE' +----------------------------- + + -- GIMPLE function: gimple gimple_build_omp_continue (tree + control_def, tree control_use) + Build a `GIMPLE_OMP_CONTINUE' statement. `CONTROL_DEF' is the + definition of the control variable. `CONTROL_USE' is the use of + the control variable. + + -- GIMPLE function: tree gimple_omp_continue_control_def (gimple s) + Return the definition of the control variable on a + `GIMPLE_OMP_CONTINUE' in `S'. + + -- GIMPLE function: tree gimple_omp_continue_control_def_ptr (gimple s) + Same as above, but return the pointer. + + -- GIMPLE function: tree gimple_omp_continue_set_control_def (gimple s) + Set the control variable definition for a `GIMPLE_OMP_CONTINUE' + statement in `S'. + + -- GIMPLE function: tree gimple_omp_continue_control_use (gimple s) + Return the use of the control variable on a `GIMPLE_OMP_CONTINUE' + in `S'. + + -- GIMPLE function: tree gimple_omp_continue_control_use_ptr (gimple s) + Same as above, but return the pointer. + + -- GIMPLE function: tree gimple_omp_continue_set_control_use (gimple s) + Set the control variable use for a `GIMPLE_OMP_CONTINUE' statement + in `S'. + + +File: gccint.info, Node: `GIMPLE_OMP_CRITICAL', Next: `GIMPLE_OMP_FOR', Prev: `GIMPLE_OMP_CONTINUE', Up: Tuple specific accessors + +12.7.14 `GIMPLE_OMP_CRITICAL' +----------------------------- + + -- GIMPLE function: gimple gimple_build_omp_critical (gimple_seq body, + tree name) + Build a `GIMPLE_OMP_CRITICAL' statement. `BODY' is the sequence of + statements for which only one thread can execute. `NAME' is an + optional identifier for this critical block. + + -- GIMPLE function: tree gimple_omp_critical_name (gimple g) + Return the name associated with `OMP_CRITICAL' statement `G'. + + -- GIMPLE function: tree * gimple_omp_critical_name_ptr (gimple g) + Return a pointer to the name associated with `OMP' critical + statement `G'. + + -- GIMPLE function: void gimple_omp_critical_set_name (gimple g, tree + name) + Set `NAME' to be the name associated with `OMP' critical statement + `G'. + + +File: gccint.info, Node: `GIMPLE_OMP_FOR', Next: `GIMPLE_OMP_MASTER', Prev: `GIMPLE_OMP_CRITICAL', Up: Tuple specific accessors + +12.7.15 `GIMPLE_OMP_FOR' +------------------------ + + -- GIMPLE function: gimple gimple_build_omp_for (gimple_seq body, tree + clauses, tree index, tree initial, tree final, tree incr, + gimple_seq pre_body, enum tree_code omp_for_cond) + Build a `GIMPLE_OMP_FOR' statement. `BODY' is sequence of + statements inside the for loop. `CLAUSES', are any of the `OMP' + loop construct's clauses: private, firstprivate, lastprivate, + reductions, ordered, schedule, and nowait. `PRE_BODY' is the + sequence of statements that are loop invariant. `INDEX' is the + index variable. `INITIAL' is the initial value of `INDEX'. + `FINAL' is final value of `INDEX'. OMP_FOR_COND is the predicate + used to compare `INDEX' and `FINAL'. `INCR' is the increment + expression. + + -- GIMPLE function: tree gimple_omp_for_clauses (gimple g) + Return the clauses associated with `OMP_FOR' `G'. + + -- GIMPLE function: tree * gimple_omp_for_clauses_ptr (gimple g) + Return a pointer to the `OMP_FOR' `G'. + + -- GIMPLE function: void gimple_omp_for_set_clauses (gimple g, tree + clauses) + Set `CLAUSES' to be the list of clauses associated with `OMP_FOR' + `G'. + + -- GIMPLE function: tree gimple_omp_for_index (gimple g) + Return the index variable for `OMP_FOR' `G'. + + -- GIMPLE function: tree * gimple_omp_for_index_ptr (gimple g) + Return a pointer to the index variable for `OMP_FOR' `G'. + + -- GIMPLE function: void gimple_omp_for_set_index (gimple g, tree + index) + Set `INDEX' to be the index variable for `OMP_FOR' `G'. + + -- GIMPLE function: tree gimple_omp_for_initial (gimple g) + Return the initial value for `OMP_FOR' `G'. + + -- GIMPLE function: tree * gimple_omp_for_initial_ptr (gimple g) + Return a pointer to the initial value for `OMP_FOR' `G'. + + -- GIMPLE function: void gimple_omp_for_set_initial (gimple g, tree + initial) + Set `INITIAL' to be the initial value for `OMP_FOR' `G'. + + -- GIMPLE function: tree gimple_omp_for_final (gimple g) + Return the final value for `OMP_FOR' `G'. + + -- GIMPLE function: tree * gimple_omp_for_final_ptr (gimple g) + turn a pointer to the final value for `OMP_FOR' `G'. + + -- GIMPLE function: void gimple_omp_for_set_final (gimple g, tree + final) + Set `FINAL' to be the final value for `OMP_FOR' `G'. + + -- GIMPLE function: tree gimple_omp_for_incr (gimple g) + Return the increment value for `OMP_FOR' `G'. + + -- GIMPLE function: tree * gimple_omp_for_incr_ptr (gimple g) + Return a pointer to the increment value for `OMP_FOR' `G'. + + -- GIMPLE function: void gimple_omp_for_set_incr (gimple g, tree incr) + Set `INCR' to be the increment value for `OMP_FOR' `G'. + + -- GIMPLE function: gimple_seq gimple_omp_for_pre_body (gimple g) + Return the sequence of statements to execute before the `OMP_FOR' + statement `G' starts. + + -- GIMPLE function: void gimple_omp_for_set_pre_body (gimple g, + gimple_seq pre_body) + Set `PRE_BODY' to be the sequence of statements to execute before + the `OMP_FOR' statement `G' starts. + + -- GIMPLE function: void gimple_omp_for_set_cond (gimple g, enum + tree_code cond) + Set `COND' to be the condition code for `OMP_FOR' `G'. + + -- GIMPLE function: enum tree_code gimple_omp_for_cond (gimple g) + Return the condition code associated with `OMP_FOR' `G'. + + +File: gccint.info, Node: `GIMPLE_OMP_MASTER', Next: `GIMPLE_OMP_ORDERED', Prev: `GIMPLE_OMP_FOR', Up: Tuple specific accessors + +12.7.16 `GIMPLE_OMP_MASTER' +--------------------------- + + -- GIMPLE function: gimple gimple_build_omp_master (gimple_seq body) + Build a `GIMPLE_OMP_MASTER' statement. `BODY' is the sequence of + statements to be executed by just the master. + + +File: gccint.info, Node: `GIMPLE_OMP_ORDERED', Next: `GIMPLE_OMP_PARALLEL', Prev: `GIMPLE_OMP_MASTER', Up: Tuple specific accessors + +12.7.17 `GIMPLE_OMP_ORDERED' +---------------------------- + + -- GIMPLE function: gimple gimple_build_omp_ordered (gimple_seq body) + Build a `GIMPLE_OMP_ORDERED' statement. + + `BODY' is the sequence of statements inside a loop that will executed +in sequence. + + +File: gccint.info, Node: `GIMPLE_OMP_PARALLEL', Next: `GIMPLE_OMP_RETURN', Prev: `GIMPLE_OMP_ORDERED', Up: Tuple specific accessors + +12.7.18 `GIMPLE_OMP_PARALLEL' +----------------------------- + + -- GIMPLE function: gimple gimple_build_omp_parallel (gimple_seq body, + tree clauses, tree child_fn, tree data_arg) + Build a `GIMPLE_OMP_PARALLEL' statement. + + `BODY' is sequence of statements which are executed in parallel. +`CLAUSES', are the `OMP' parallel construct's clauses. `CHILD_FN' is +the function created for the parallel threads to execute. `DATA_ARG' +are the shared data argument(s). + + -- GIMPLE function: bool gimple_omp_parallel_combined_p (gimple g) + Return true if `OMP' parallel statement `G' has the + `GF_OMP_PARALLEL_COMBINED' flag set. + + -- GIMPLE function: void gimple_omp_parallel_set_combined_p (gimple g) + Set the `GF_OMP_PARALLEL_COMBINED' field in `OMP' parallel + statement `G'. + + -- GIMPLE function: gimple_seq gimple_omp_body (gimple g) + Return the body for the `OMP' statement `G'. + + -- GIMPLE function: void gimple_omp_set_body (gimple g, gimple_seq + body) + Set `BODY' to be the body for the `OMP' statement `G'. + + -- GIMPLE function: tree gimple_omp_parallel_clauses (gimple g) + Return the clauses associated with `OMP_PARALLEL' `G'. + + -- GIMPLE function: tree * gimple_omp_parallel_clauses_ptr (gimple g) + Return a pointer to the clauses associated with `OMP_PARALLEL' `G'. + + -- GIMPLE function: void gimple_omp_parallel_set_clauses (gimple g, + tree clauses) + Set `CLAUSES' to be the list of clauses associated with + `OMP_PARALLEL' `G'. + + -- GIMPLE function: tree gimple_omp_parallel_child_fn (gimple g) + Return the child function used to hold the body of `OMP_PARALLEL' + `G'. + + -- GIMPLE function: tree * gimple_omp_parallel_child_fn_ptr (gimple g) + Return a pointer to the child function used to hold the body of + `OMP_PARALLEL' `G'. + + -- GIMPLE function: void gimple_omp_parallel_set_child_fn (gimple g, + tree child_fn) + Set `CHILD_FN' to be the child function for `OMP_PARALLEL' `G'. + + -- GIMPLE function: tree gimple_omp_parallel_data_arg (gimple g) + Return the artificial argument used to send variables and values + from the parent to the children threads in `OMP_PARALLEL' `G'. + + -- GIMPLE function: tree * gimple_omp_parallel_data_arg_ptr (gimple g) + Return a pointer to the data argument for `OMP_PARALLEL' `G'. + + -- GIMPLE function: void gimple_omp_parallel_set_data_arg (gimple g, + tree data_arg) + Set `DATA_ARG' to be the data argument for `OMP_PARALLEL' `G'. + + -- GIMPLE function: bool is_gimple_omp (gimple stmt) + Returns true when the gimple statement `STMT' is any of the OpenMP + types. + + +File: gccint.info, Node: `GIMPLE_OMP_RETURN', Next: `GIMPLE_OMP_SECTION', Prev: `GIMPLE_OMP_PARALLEL', Up: Tuple specific accessors + +12.7.19 `GIMPLE_OMP_RETURN' +--------------------------- + + -- GIMPLE function: gimple gimple_build_omp_return (bool wait_p) + Build a `GIMPLE_OMP_RETURN' statement. `WAIT_P' is true if this is + a non-waiting return. + + -- GIMPLE function: void gimple_omp_return_set_nowait (gimple s) + Set the nowait flag on `GIMPLE_OMP_RETURN' statement `S'. + + -- GIMPLE function: bool gimple_omp_return_nowait_p (gimple g) + Return true if `OMP' return statement `G' has the + `GF_OMP_RETURN_NOWAIT' flag set. + + +File: gccint.info, Node: `GIMPLE_OMP_SECTION', Next: `GIMPLE_OMP_SECTIONS', Prev: `GIMPLE_OMP_RETURN', Up: Tuple specific accessors + +12.7.20 `GIMPLE_OMP_SECTION' +---------------------------- + + -- GIMPLE function: gimple gimple_build_omp_section (gimple_seq body) + Build a `GIMPLE_OMP_SECTION' statement for a sections statement. + + `BODY' is the sequence of statements in the section. + + -- GIMPLE function: bool gimple_omp_section_last_p (gimple g) + Return true if `OMP' section statement `G' has the + `GF_OMP_SECTION_LAST' flag set. + + -- GIMPLE function: void gimple_omp_section_set_last (gimple g) + Set the `GF_OMP_SECTION_LAST' flag on `G'. + + +File: gccint.info, Node: `GIMPLE_OMP_SECTIONS', Next: `GIMPLE_OMP_SINGLE', Prev: `GIMPLE_OMP_SECTION', Up: Tuple specific accessors + +12.7.21 `GIMPLE_OMP_SECTIONS' +----------------------------- + + -- GIMPLE function: gimple gimple_build_omp_sections (gimple_seq body, + tree clauses) + Build a `GIMPLE_OMP_SECTIONS' statement. `BODY' is a sequence of + section statements. `CLAUSES' are any of the `OMP' sections + construct's clauses: private, firstprivate, lastprivate, + reduction, and nowait. + + -- GIMPLE function: gimple gimple_build_omp_sections_switch (void) + Build a `GIMPLE_OMP_SECTIONS_SWITCH' statement. + + -- GIMPLE function: tree gimple_omp_sections_control (gimple g) + Return the control variable associated with the + `GIMPLE_OMP_SECTIONS' in `G'. + + -- GIMPLE function: tree * gimple_omp_sections_control_ptr (gimple g) + Return a pointer to the clauses associated with the + `GIMPLE_OMP_SECTIONS' in `G'. + + -- GIMPLE function: void gimple_omp_sections_set_control (gimple g, + tree control) + Set `CONTROL' to be the set of clauses associated with the + `GIMPLE_OMP_SECTIONS' in `G'. + + -- GIMPLE function: tree gimple_omp_sections_clauses (gimple g) + Return the clauses associated with `OMP_SECTIONS' `G'. + + -- GIMPLE function: tree * gimple_omp_sections_clauses_ptr (gimple g) + Return a pointer to the clauses associated with `OMP_SECTIONS' `G'. + + -- GIMPLE function: void gimple_omp_sections_set_clauses (gimple g, + tree clauses) + Set `CLAUSES' to be the set of clauses associated with + `OMP_SECTIONS' `G'. + + +File: gccint.info, Node: `GIMPLE_OMP_SINGLE', Next: `GIMPLE_PHI', Prev: `GIMPLE_OMP_SECTIONS', Up: Tuple specific accessors + +12.7.22 `GIMPLE_OMP_SINGLE' +--------------------------- + + -- GIMPLE function: gimple gimple_build_omp_single (gimple_seq body, + tree clauses) + Build a `GIMPLE_OMP_SINGLE' statement. `BODY' is the sequence of + statements that will be executed once. `CLAUSES' are any of the + `OMP' single construct's clauses: private, firstprivate, + copyprivate, nowait. + + -- GIMPLE function: tree gimple_omp_single_clauses (gimple g) + Return the clauses associated with `OMP_SINGLE' `G'. + + -- GIMPLE function: tree * gimple_omp_single_clauses_ptr (gimple g) + Return a pointer to the clauses associated with `OMP_SINGLE' `G'. + + -- GIMPLE function: void gimple_omp_single_set_clauses (gimple g, tree + clauses) + Set `CLAUSES' to be the clauses associated with `OMP_SINGLE' `G'. + + +File: gccint.info, Node: `GIMPLE_PHI', Next: `GIMPLE_RESX', Prev: `GIMPLE_OMP_SINGLE', Up: Tuple specific accessors + +12.7.23 `GIMPLE_PHI' +-------------------- + + -- GIMPLE function: gimple make_phi_node (tree var, int len) + Build a `PHI' node with len argument slots for variable var. + + -- GIMPLE function: unsigned gimple_phi_capacity (gimple g) + Return the maximum number of arguments supported by `GIMPLE_PHI' + `G'. + + -- GIMPLE function: unsigned gimple_phi_num_args (gimple g) + Return the number of arguments in `GIMPLE_PHI' `G'. This must + always be exactly the number of incoming edges for the basic block + holding `G'. + + -- GIMPLE function: tree gimple_phi_result (gimple g) + Return the `SSA' name created by `GIMPLE_PHI' `G'. + + -- GIMPLE function: tree * gimple_phi_result_ptr (gimple g) + Return a pointer to the `SSA' name created by `GIMPLE_PHI' `G'. + + -- GIMPLE function: void gimple_phi_set_result (gimple g, tree result) + Set `RESULT' to be the `SSA' name created by `GIMPLE_PHI' `G'. + + -- GIMPLE function: struct phi_arg_d * gimple_phi_arg (gimple g, index) + Return the `PHI' argument corresponding to incoming edge `INDEX' + for `GIMPLE_PHI' `G'. + + -- GIMPLE function: void gimple_phi_set_arg (gimple g, index, struct + phi_arg_d * phiarg) + Set `PHIARG' to be the argument corresponding to incoming edge + `INDEX' for `GIMPLE_PHI' `G'. + + +File: gccint.info, Node: `GIMPLE_RESX', Next: `GIMPLE_RETURN', Prev: `GIMPLE_PHI', Up: Tuple specific accessors + +12.7.24 `GIMPLE_RESX' +--------------------- + + -- GIMPLE function: gimple gimple_build_resx (int region) + Build a `GIMPLE_RESX' statement which is a statement. This + statement is a placeholder for _Unwind_Resume before we know if a + function call or a branch is needed. `REGION' is the exception + region from which control is flowing. + + -- GIMPLE function: int gimple_resx_region (gimple g) + Return the region number for `GIMPLE_RESX' `G'. + + -- GIMPLE function: void gimple_resx_set_region (gimple g, int region) + Set `REGION' to be the region number for `GIMPLE_RESX' `G'. + + +File: gccint.info, Node: `GIMPLE_RETURN', Next: `GIMPLE_SWITCH', Prev: `GIMPLE_RESX', Up: Tuple specific accessors + +12.7.25 `GIMPLE_RETURN' +----------------------- + + -- GIMPLE function: gimple gimple_build_return (tree retval) + Build a `GIMPLE_RETURN' statement whose return value is retval. + + -- GIMPLE function: tree gimple_return_retval (gimple g) + Return the return value for `GIMPLE_RETURN' `G'. + + -- GIMPLE function: void gimple_return_set_retval (gimple g, tree + retval) + Set `RETVAL' to be the return value for `GIMPLE_RETURN' `G'. + + +File: gccint.info, Node: `GIMPLE_SWITCH', Next: `GIMPLE_TRY', Prev: `GIMPLE_RETURN', Up: Tuple specific accessors + +12.7.26 `GIMPLE_SWITCH' +----------------------- + + -- GIMPLE function: gimple gimple_build_switch (unsigned nlabels, tree + index, tree default_label, ...) + Build a `GIMPLE_SWITCH' statement. `NLABELS' are the number of + labels excluding the default label. The default label is passed + in `DEFAULT_LABEL'. The rest of the arguments are trees + representing the labels. Each label is a tree of code + `CASE_LABEL_EXPR'. + + -- GIMPLE function: gimple gimple_build_switch_vec (tree index, tree + default_label, `VEC'(tree,heap) *args) + This function is an alternate way of building `GIMPLE_SWITCH' + statements. `INDEX' and `DEFAULT_LABEL' are as in + gimple_build_switch. `ARGS' is a vector of `CASE_LABEL_EXPR' trees + that contain the labels. + + -- GIMPLE function: unsigned gimple_switch_num_labels (gimple g) + Return the number of labels associated with the switch statement + `G'. + + -- GIMPLE function: void gimple_switch_set_num_labels (gimple g, + unsigned nlabels) + Set `NLABELS' to be the number of labels for the switch statement + `G'. + + -- GIMPLE function: tree gimple_switch_index (gimple g) + Return the index variable used by the switch statement `G'. + + -- GIMPLE function: void gimple_switch_set_index (gimple g, tree index) + Set `INDEX' to be the index variable for switch statement `G'. + + -- GIMPLE function: tree gimple_switch_label (gimple g, unsigned index) + Return the label numbered `INDEX'. The default label is 0, followed + by any labels in a switch statement. + + -- GIMPLE function: void gimple_switch_set_label (gimple g, unsigned + index, tree label) + Set the label number `INDEX' to `LABEL'. 0 is always the default + label. + + -- GIMPLE function: tree gimple_switch_default_label (gimple g) + Return the default label for a switch statement. + + -- GIMPLE function: void gimple_switch_set_default_label (gimple g, + tree label) + Set the default label for a switch statement. + + +File: gccint.info, Node: `GIMPLE_TRY', Next: `GIMPLE_WITH_CLEANUP_EXPR', Prev: `GIMPLE_SWITCH', Up: Tuple specific accessors + +12.7.27 `GIMPLE_TRY' +-------------------- + + -- GIMPLE function: gimple gimple_build_try (gimple_seq eval, + gimple_seq cleanup, unsigned int kind) + Build a `GIMPLE_TRY' statement. `EVAL' is a sequence with the + expression to evaluate. `CLEANUP' is a sequence of statements to + run at clean-up time. `KIND' is the enumeration value + `GIMPLE_TRY_CATCH' if this statement denotes a try/catch construct + or `GIMPLE_TRY_FINALLY' if this statement denotes a try/finally + construct. + + -- GIMPLE function: enum gimple_try_flags gimple_try_kind (gimple g) + Return the kind of try block represented by `GIMPLE_TRY' `G'. This + is either `GIMPLE_TRY_CATCH' or `GIMPLE_TRY_FINALLY'. + + -- GIMPLE function: bool gimple_try_catch_is_cleanup (gimple g) + Return the `GIMPLE_TRY_CATCH_IS_CLEANUP' flag. + + -- GIMPLE function: gimple_seq gimple_try_eval (gimple g) + Return the sequence of statements used as the body for `GIMPLE_TRY' + `G'. + + -- GIMPLE function: gimple_seq gimple_try_cleanup (gimple g) + Return the sequence of statements used as the cleanup body for + `GIMPLE_TRY' `G'. + + -- GIMPLE function: void gimple_try_set_catch_is_cleanup (gimple g, + bool catch_is_cleanup) + Set the `GIMPLE_TRY_CATCH_IS_CLEANUP' flag. + + -- GIMPLE function: void gimple_try_set_eval (gimple g, gimple_seq + eval) + Set `EVAL' to be the sequence of statements to use as the body for + `GIMPLE_TRY' `G'. + + -- GIMPLE function: void gimple_try_set_cleanup (gimple g, gimple_seq + cleanup) + Set `CLEANUP' to be the sequence of statements to use as the + cleanup body for `GIMPLE_TRY' `G'. + + +File: gccint.info, Node: `GIMPLE_WITH_CLEANUP_EXPR', Prev: `GIMPLE_TRY', Up: Tuple specific accessors + +12.7.28 `GIMPLE_WITH_CLEANUP_EXPR' +---------------------------------- + + -- GIMPLE function: gimple gimple_build_wce (gimple_seq cleanup) + Build a `GIMPLE_WITH_CLEANUP_EXPR' statement. `CLEANUP' is the + clean-up expression. + + -- GIMPLE function: gimple_seq gimple_wce_cleanup (gimple g) + Return the cleanup sequence for cleanup statement `G'. + + -- GIMPLE function: void gimple_wce_set_cleanup (gimple g, gimple_seq + cleanup) + Set `CLEANUP' to be the cleanup sequence for `G'. + + -- GIMPLE function: bool gimple_wce_cleanup_eh_only (gimple g) + Return the `CLEANUP_EH_ONLY' flag for a `WCE' tuple. + + -- GIMPLE function: void gimple_wce_set_cleanup_eh_only (gimple g, + bool eh_only_p) + Set the `CLEANUP_EH_ONLY' flag for a `WCE' tuple. + + +File: gccint.info, Node: GIMPLE sequences, Next: Sequence iterators, Prev: Tuple specific accessors, Up: GIMPLE + +12.8 GIMPLE sequences +===================== + +GIMPLE sequences are the tuple equivalent of `STATEMENT_LIST''s used in +`GENERIC'. They are used to chain statements together, and when used +in conjunction with sequence iterators, provide a framework for +iterating through statements. + + GIMPLE sequences are of type struct `gimple_sequence', but are more +commonly passed by reference to functions dealing with sequences. The +type for a sequence pointer is `gimple_seq' which is the same as struct +`gimple_sequence' *. When declaring a local sequence, you can define a +local variable of type struct `gimple_sequence'. When declaring a +sequence allocated on the garbage collected heap, use the function +`gimple_seq_alloc' documented below. + + There are convenience functions for iterating through sequences in the +section entitled Sequence Iterators. + + Below is a list of functions to manipulate and query sequences. + + -- GIMPLE function: void gimple_seq_add_stmt (gimple_seq *seq, gimple + g) + Link a gimple statement to the end of the sequence *`SEQ' if `G' is + not `NULL'. If *`SEQ' is `NULL', allocate a sequence before + linking. + + -- GIMPLE function: void gimple_seq_add_seq (gimple_seq *dest, + gimple_seq src) + Append sequence `SRC' to the end of sequence *`DEST' if `SRC' is + not `NULL'. If *`DEST' is `NULL', allocate a new sequence before + appending. + + -- GIMPLE function: gimple_seq gimple_seq_deep_copy (gimple_seq src) + Perform a deep copy of sequence `SRC' and return the result. + + -- GIMPLE function: gimple_seq gimple_seq_reverse (gimple_seq seq) + Reverse the order of the statements in the sequence `SEQ'. Return + `SEQ'. + + -- GIMPLE function: gimple gimple_seq_first (gimple_seq s) + Return the first statement in sequence `S'. + + -- GIMPLE function: gimple gimple_seq_last (gimple_seq s) + Return the last statement in sequence `S'. + + -- GIMPLE function: void gimple_seq_set_last (gimple_seq s, gimple + last) + Set the last statement in sequence `S' to the statement in `LAST'. + + -- GIMPLE function: void gimple_seq_set_first (gimple_seq s, gimple + first) + Set the first statement in sequence `S' to the statement in + `FIRST'. + + -- GIMPLE function: void gimple_seq_init (gimple_seq s) + Initialize sequence `S' to an empty sequence. + + -- GIMPLE function: gimple_seq gimple_seq_alloc (void) + Allocate a new sequence in the garbage collected store and return + it. + + -- GIMPLE function: void gimple_seq_copy (gimple_seq dest, gimple_seq + src) + Copy the sequence `SRC' into the sequence `DEST'. + + -- GIMPLE function: bool gimple_seq_empty_p (gimple_seq s) + Return true if the sequence `S' is empty. + + -- GIMPLE function: gimple_seq bb_seq (basic_block bb) + Returns the sequence of statements in `BB'. + + -- GIMPLE function: void set_bb_seq (basic_block bb, gimple_seq seq) + Sets the sequence of statements in `BB' to `SEQ'. + + -- GIMPLE function: bool gimple_seq_singleton_p (gimple_seq seq) + Determine whether `SEQ' contains exactly one statement. + + +File: gccint.info, Node: Sequence iterators, Next: Adding a new GIMPLE statement code, Prev: GIMPLE sequences, Up: GIMPLE + +12.9 Sequence iterators +======================= + +Sequence iterators are convenience constructs for iterating through +statements in a sequence. Given a sequence `SEQ', here is a typical +use of gimple sequence iterators: + + gimple_stmt_iterator gsi; + + for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple g = gsi_stmt (gsi); + /* Do something with gimple statement `G'. */ + } + + Backward iterations are possible: + + for (gsi = gsi_last (seq); !gsi_end_p (gsi); gsi_prev (&gsi)) + + Forward and backward iterations on basic blocks are possible with +`gsi_start_bb' and `gsi_last_bb'. + + In the documentation below we sometimes refer to enum +`gsi_iterator_update'. The valid options for this enumeration are: + + * `GSI_NEW_STMT' Only valid when a single statement is added. Move + the iterator to it. + + * `GSI_SAME_STMT' Leave the iterator at the same statement. + + * `GSI_CONTINUE_LINKING' Move iterator to whatever position is + suitable for linking other statements in the same direction. + + Below is a list of the functions used to manipulate and use statement +iterators. + + -- GIMPLE function: gimple_stmt_iterator gsi_start (gimple_seq seq) + Return a new iterator pointing to the sequence `SEQ''s first + statement. If `SEQ' is empty, the iterator's basic block is + `NULL'. Use `gsi_start_bb' instead when the iterator needs to + always have the correct basic block set. + + -- GIMPLE function: gimple_stmt_iterator gsi_start_bb (basic_block bb) + Return a new iterator pointing to the first statement in basic + block `BB'. + + -- GIMPLE function: gimple_stmt_iterator gsi_last (gimple_seq seq) + Return a new iterator initially pointing to the last statement of + sequence `SEQ'. If `SEQ' is empty, the iterator's basic block is + `NULL'. Use `gsi_last_bb' instead when the iterator needs to + always have the correct basic block set. + + -- GIMPLE function: gimple_stmt_iterator gsi_last_bb (basic_block bb) + Return a new iterator pointing to the last statement in basic + block `BB'. + + -- GIMPLE function: bool gsi_end_p (gimple_stmt_iterator i) + Return `TRUE' if at the end of `I'. + + -- GIMPLE function: bool gsi_one_before_end_p (gimple_stmt_iterator i) + Return `TRUE' if we're one statement before the end of `I'. + + -- GIMPLE function: void gsi_next (gimple_stmt_iterator *i) + Advance the iterator to the next gimple statement. + + -- GIMPLE function: void gsi_prev (gimple_stmt_iterator *i) + Advance the iterator to the previous gimple statement. + + -- GIMPLE function: gimple gsi_stmt (gimple_stmt_iterator i) + Return the current stmt. + + -- GIMPLE function: gimple_stmt_iterator gsi_after_labels (basic_block + bb) + Return a block statement iterator that points to the first + non-label statement in block `BB'. + + -- GIMPLE function: gimple * gsi_stmt_ptr (gimple_stmt_iterator *i) + Return a pointer to the current stmt. + + -- GIMPLE function: basic_block gsi_bb (gimple_stmt_iterator i) + Return the basic block associated with this iterator. + + -- GIMPLE function: gimple_seq gsi_seq (gimple_stmt_iterator i) + Return the sequence associated with this iterator. + + -- GIMPLE function: void gsi_remove (gimple_stmt_iterator *i, bool + remove_eh_info) + Remove the current stmt from the sequence. The iterator is + updated to point to the next statement. When `REMOVE_EH_INFO' is + true we remove the statement pointed to by iterator `I' from the + `EH' tables. Otherwise we do not modify the `EH' tables. + Generally, `REMOVE_EH_INFO' should be true when the statement is + going to be removed from the `IL' and not reinserted elsewhere. + + -- GIMPLE function: void gsi_link_seq_before (gimple_stmt_iterator *i, + gimple_seq seq, enum gsi_iterator_update mode) + Links the sequence of statements `SEQ' before the statement pointed + by iterator `I'. `MODE' indicates what to do with the iterator + after insertion (see `enum gsi_iterator_update' above). + + -- GIMPLE function: void gsi_link_before (gimple_stmt_iterator *i, + gimple g, enum gsi_iterator_update mode) + Links statement `G' before the statement pointed-to by iterator + `I'. Updates iterator `I' according to `MODE'. + + -- GIMPLE function: void gsi_link_seq_after (gimple_stmt_iterator *i, + gimple_seq seq, enum gsi_iterator_update mode) + Links sequence `SEQ' after the statement pointed-to by iterator + `I'. `MODE' is as in `gsi_insert_after'. + + -- GIMPLE function: void gsi_link_after (gimple_stmt_iterator *i, + gimple g, enum gsi_iterator_update mode) + Links statement `G' after the statement pointed-to by iterator `I'. + `MODE' is as in `gsi_insert_after'. + + -- GIMPLE function: gimple_seq gsi_split_seq_after + (gimple_stmt_iterator i) + Move all statements in the sequence after `I' to a new sequence. + Return this new sequence. + + -- GIMPLE function: gimple_seq gsi_split_seq_before + (gimple_stmt_iterator *i) + Move all statements in the sequence before `I' to a new sequence. + Return this new sequence. + + -- GIMPLE function: void gsi_replace (gimple_stmt_iterator *i, gimple + stmt, bool update_eh_info) + Replace the statement pointed-to by `I' to `STMT'. If + `UPDATE_EH_INFO' is true, the exception handling information of + the original statement is moved to the new statement. + + -- GIMPLE function: void gsi_insert_before (gimple_stmt_iterator *i, + gimple stmt, enum gsi_iterator_update mode) + Insert statement `STMT' before the statement pointed-to by iterator + `I', update `STMT''s basic block and scan it for new operands. + `MODE' specifies how to update iterator `I' after insertion (see + enum `gsi_iterator_update'). + + -- GIMPLE function: void gsi_insert_seq_before (gimple_stmt_iterator + *i, gimple_seq seq, enum gsi_iterator_update mode) + Like `gsi_insert_before', but for all the statements in `SEQ'. + + -- GIMPLE function: void gsi_insert_after (gimple_stmt_iterator *i, + gimple stmt, enum gsi_iterator_update mode) + Insert statement `STMT' after the statement pointed-to by iterator + `I', update `STMT''s basic block and scan it for new operands. + `MODE' specifies how to update iterator `I' after insertion (see + enum `gsi_iterator_update'). + + -- GIMPLE function: void gsi_insert_seq_after (gimple_stmt_iterator + *i, gimple_seq seq, enum gsi_iterator_update mode) + Like `gsi_insert_after', but for all the statements in `SEQ'. + + -- GIMPLE function: gimple_stmt_iterator gsi_for_stmt (gimple stmt) + Finds iterator for `STMT'. + + -- GIMPLE function: void gsi_move_after (gimple_stmt_iterator *from, + gimple_stmt_iterator *to) + Move the statement at `FROM' so it comes right after the statement + at `TO'. + + -- GIMPLE function: void gsi_move_before (gimple_stmt_iterator *from, + gimple_stmt_iterator *to) + Move the statement at `FROM' so it comes right before the statement + at `TO'. + + -- GIMPLE function: void gsi_move_to_bb_end (gimple_stmt_iterator + *from, basic_block bb) + Move the statement at `FROM' to the end of basic block `BB'. + + -- GIMPLE function: void gsi_insert_on_edge (edge e, gimple stmt) + Add `STMT' to the pending list of edge `E'. No actual insertion is + made until a call to `gsi_commit_edge_inserts'() is made. + + -- GIMPLE function: void gsi_insert_seq_on_edge (edge e, gimple_seq + seq) + Add the sequence of statements in `SEQ' to the pending list of edge + `E'. No actual insertion is made until a call to + `gsi_commit_edge_inserts'() is made. + + -- GIMPLE function: basic_block gsi_insert_on_edge_immediate (edge e, + gimple stmt) + Similar to `gsi_insert_on_edge'+`gsi_commit_edge_inserts'. If a + new block has to be created, it is returned. + + -- GIMPLE function: void gsi_commit_one_edge_insert (edge e, + basic_block *new_bb) + Commit insertions pending at edge `E'. If a new block is created, + set `NEW_BB' to this block, otherwise set it to `NULL'. + + -- GIMPLE function: void gsi_commit_edge_inserts (void) + This routine will commit all pending edge insertions, creating any + new basic blocks which are necessary. + + +File: gccint.info, Node: Adding a new GIMPLE statement code, Next: Statement and operand traversals, Prev: Sequence iterators, Up: GIMPLE + +12.10 Adding a new GIMPLE statement code +======================================== + +The first step in adding a new GIMPLE statement code, is modifying the +file `gimple.def', which contains all the GIMPLE codes. Then you must +add a corresponding structure, and an entry in `union +gimple_statement_d', both of which are located in `gimple.h'. This in +turn, will require you to add a corresponding `GTY' tag in +`gsstruct.def', and code to handle this tag in `gss_for_code' which is +located in `gimple.c'. + + In order for the garbage collector to know the size of the structure +you created in `gimple.h', you need to add a case to handle your new +GIMPLE statement in `gimple_size' which is located in `gimple.c'. + + You will probably want to create a function to build the new gimple +statement in `gimple.c'. The function should be called +`gimple_build_NEW-TUPLE-NAME', and should return the new tuple of type +gimple. + + If your new statement requires accessors for any members or operands +it may have, put simple inline accessors in `gimple.h' and any +non-trivial accessors in `gimple.c' with a corresponding prototype in +`gimple.h'. + + +File: gccint.info, Node: Statement and operand traversals, Prev: Adding a new GIMPLE statement code, Up: GIMPLE + +12.11 Statement and operand traversals +====================================== + +There are two functions available for walking statements and sequences: +`walk_gimple_stmt' and `walk_gimple_seq', accordingly, and a third +function for walking the operands in a statement: `walk_gimple_op'. + + -- GIMPLE function: tree walk_gimple_stmt (gimple_stmt_iterator *gsi, + walk_stmt_fn callback_stmt, walk_tree_fn callback_op, struct + walk_stmt_info *wi) + This function is used to walk the current statement in `GSI', + optionally using traversal state stored in `WI'. If `WI' is + `NULL', no state is kept during the traversal. + + The callback `CALLBACK_STMT' is called. If `CALLBACK_STMT' returns + true, it means that the callback function has handled all the + operands of the statement and it is not necessary to walk its + operands. + + If `CALLBACK_STMT' is `NULL' or it returns false, `CALLBACK_OP' is + called on each operand of the statement via `walk_gimple_op'. If + `walk_gimple_op' returns non-`NULL' for any operand, the remaining + operands are not scanned. + + The return value is that returned by the last call to + `walk_gimple_op', or `NULL_TREE' if no `CALLBACK_OP' is specified. + + -- GIMPLE function: tree walk_gimple_op (gimple stmt, walk_tree_fn + callback_op, struct walk_stmt_info *wi) + Use this function to walk the operands of statement `STMT'. Every + operand is walked via `walk_tree' with optional state information + in `WI'. + + `CALLBACK_OP' is called on each operand of `STMT' via `walk_tree'. + Additional parameters to `walk_tree' must be stored in `WI'. For + each operand `OP', `walk_tree' is called as: + + walk_tree (&`OP', `CALLBACK_OP', `WI', `PSET') + + If `CALLBACK_OP' returns non-`NULL' for an operand, the remaining + operands are not scanned. The return value is that returned by + the last call to `walk_tree', or `NULL_TREE' if no `CALLBACK_OP' is + specified. + + -- GIMPLE function: tree walk_gimple_seq (gimple_seq seq, walk_stmt_fn + callback_stmt, walk_tree_fn callback_op, struct + walk_stmt_info *wi) + This function walks all the statements in the sequence `SEQ' + calling `walk_gimple_stmt' on each one. `WI' is as in + `walk_gimple_stmt'. If `walk_gimple_stmt' returns non-`NULL', the + walk is stopped and the value returned. Otherwise, all the + statements are walked and `NULL_TREE' returned. + + +File: gccint.info, Node: Tree SSA, Next: RTL, Prev: GIMPLE, Up: Top + +13 Analysis and Optimization of GIMPLE tuples +********************************************* + +GCC uses three main intermediate languages to represent the program +during compilation: GENERIC, GIMPLE and RTL. GENERIC is a +language-independent representation generated by each front end. It is +used to serve as an interface between the parser and optimizer. +GENERIC is a common representation that is able to represent programs +written in all the languages supported by GCC. + + GIMPLE and RTL are used to optimize the program. GIMPLE is used for +target and language independent optimizations (e.g., inlining, constant +propagation, tail call elimination, redundancy elimination, etc). Much +like GENERIC, GIMPLE is a language independent, tree based +representation. However, it differs from GENERIC in that the GIMPLE +grammar is more restrictive: expressions contain no more than 3 +operands (except function calls), it has no control flow structures and +expressions with side-effects are only allowed on the right hand side +of assignments. See the chapter describing GENERIC and GIMPLE for more +details. + + This chapter describes the data structures and functions used in the +GIMPLE optimizers (also known as "tree optimizers" or "middle end"). +In particular, it focuses on all the macros, data structures, functions +and programming constructs needed to implement optimization passes for +GIMPLE. + +* Menu: + +* Annotations:: Attributes for variables. +* SSA Operands:: SSA names referenced by GIMPLE statements. +* SSA:: Static Single Assignment representation. +* Alias analysis:: Representing aliased loads and stores. +* Memory model:: Memory model used by the middle-end. + + +File: gccint.info, Node: Annotations, Next: SSA Operands, Up: Tree SSA + +13.1 Annotations +================ + +The optimizers need to associate attributes with variables during the +optimization process. For instance, we need to know whether a variable +has aliases. All these attributes are stored in data structures called +annotations which are then linked to the field `ann' in `struct +tree_common'. + + Presently, we define annotations for variables (`var_ann_t'). +Annotations are defined and documented in `tree-flow.h'. + + +File: gccint.info, Node: SSA Operands, Next: SSA, Prev: Annotations, Up: Tree SSA + +13.2 SSA Operands +================= + +Almost every GIMPLE statement will contain a reference to a variable or +memory location. Since statements come in different shapes and sizes, +their operands are going to be located at various spots inside the +statement's tree. To facilitate access to the statement's operands, +they are organized into lists associated inside each statement's +annotation. Each element in an operand list is a pointer to a +`VAR_DECL', `PARM_DECL' or `SSA_NAME' tree node. This provides a very +convenient way of examining and replacing operands. + + Data flow analysis and optimization is done on all tree nodes +representing variables. Any node for which `SSA_VAR_P' returns nonzero +is considered when scanning statement operands. However, not all +`SSA_VAR_P' variables are processed in the same way. For the purposes +of optimization, we need to distinguish between references to local +scalar variables and references to globals, statics, structures, +arrays, aliased variables, etc. The reason is simple, the compiler can +gather complete data flow information for a local scalar. On the other +hand, a global variable may be modified by a function call, it may not +be possible to keep track of all the elements of an array or the fields +of a structure, etc. + + The operand scanner gathers two kinds of operands: "real" and +"virtual". An operand for which `is_gimple_reg' returns true is +considered real, otherwise it is a virtual operand. We also +distinguish between uses and definitions. An operand is used if its +value is loaded by the statement (e.g., the operand at the RHS of an +assignment). If the statement assigns a new value to the operand, the +operand is considered a definition (e.g., the operand at the LHS of an +assignment). + + Virtual and real operands also have very different data flow +properties. Real operands are unambiguous references to the full +object that they represent. For instance, given + + { + int a, b; + a = b + } + + Since `a' and `b' are non-aliased locals, the statement `a = b' will +have one real definition and one real use because variable `a' is +completely modified with the contents of variable `b'. Real definition +are also known as "killing definitions". Similarly, the use of `b' +reads all its bits. + + In contrast, virtual operands are used with variables that can have a +partial or ambiguous reference. This includes structures, arrays, +globals, and aliased variables. In these cases, we have two types of +definitions. For globals, structures, and arrays, we can determine from +a statement whether a variable of these types has a killing definition. +If the variable does, then the statement is marked as having a "must +definition" of that variable. However, if a statement is only defining +a part of the variable (i.e. a field in a structure), or if we know +that a statement might define the variable but we cannot say for sure, +then we mark that statement as having a "may definition". For +instance, given + + { + int a, b, *p; + + if (...) + p = &a; + else + p = &b; + *p = 5; + return *p; + } + + The assignment `*p = 5' may be a definition of `a' or `b'. If we +cannot determine statically where `p' is pointing to at the time of the +store operation, we create virtual definitions to mark that statement +as a potential definition site for `a' and `b'. Memory loads are +similarly marked with virtual use operands. Virtual operands are shown +in tree dumps right before the statement that contains them. To +request a tree dump with virtual operands, use the `-vops' option to +`-fdump-tree': + + { + int a, b, *p; + + if (...) + p = &a; + else + p = &b; + # a = VDEF <a> + # b = VDEF <b> + *p = 5; + + # VUSE <a> + # VUSE <b> + return *p; + } + + Notice that `VDEF' operands have two copies of the referenced +variable. This indicates that this is not a killing definition of that +variable. In this case we refer to it as a "may definition" or +"aliased store". The presence of the second copy of the variable in +the `VDEF' operand will become important when the function is converted +into SSA form. This will be used to link all the non-killing +definitions to prevent optimizations from making incorrect assumptions +about them. + + Operands are updated as soon as the statement is finished via a call +to `update_stmt'. If statement elements are changed via `SET_USE' or +`SET_DEF', then no further action is required (i.e., those macros take +care of updating the statement). If changes are made by manipulating +the statement's tree directly, then a call must be made to +`update_stmt' when complete. Calling one of the `bsi_insert' routines +or `bsi_replace' performs an implicit call to `update_stmt'. + +13.2.1 Operand Iterators And Access Routines +-------------------------------------------- + +Operands are collected by `tree-ssa-operands.c'. They are stored +inside each statement's annotation and can be accessed through either +the operand iterators or an access routine. + + The following access routines are available for examining operands: + + 1. `SINGLE_SSA_{USE,DEF,TREE}_OPERAND': These accessors will return + NULL unless there is exactly one operand matching the specified + flags. If there is exactly one operand, the operand is returned + as either a `tree', `def_operand_p', or `use_operand_p'. + + tree t = SINGLE_SSA_TREE_OPERAND (stmt, flags); + use_operand_p u = SINGLE_SSA_USE_OPERAND (stmt, SSA_ALL_VIRTUAL_USES); + def_operand_p d = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_ALL_DEFS); + + 2. `ZERO_SSA_OPERANDS': This macro returns true if there are no + operands matching the specified flags. + + if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) + return; + + 3. `NUM_SSA_OPERANDS': This macro Returns the number of operands + matching 'flags'. This actually executes a loop to perform the + count, so only use this if it is really needed. + + int count = NUM_SSA_OPERANDS (stmt, flags) + + If you wish to iterate over some or all operands, use the +`FOR_EACH_SSA_{USE,DEF,TREE}_OPERAND' iterator. For example, to print +all the operands for a statement: + + void + print_ops (tree stmt) + { + ssa_op_iter; + tree var; + + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_OPERANDS) + print_generic_expr (stderr, var, TDF_SLIM); + } + + How to choose the appropriate iterator: + + 1. Determine whether you are need to see the operand pointers, or + just the trees, and choose the appropriate macro: + + Need Macro: + ---- ------- + use_operand_p FOR_EACH_SSA_USE_OPERAND + def_operand_p FOR_EACH_SSA_DEF_OPERAND + tree FOR_EACH_SSA_TREE_OPERAND + + 2. You need to declare a variable of the type you are interested in, + and an ssa_op_iter structure which serves as the loop controlling + variable. + + 3. Determine which operands you wish to use, and specify the flags of + those you are interested in. They are documented in + `tree-ssa-operands.h': + + #define SSA_OP_USE 0x01 /* Real USE operands. */ + #define SSA_OP_DEF 0x02 /* Real DEF operands. */ + #define SSA_OP_VUSE 0x04 /* VUSE operands. */ + #define SSA_OP_VMAYUSE 0x08 /* USE portion of VDEFS. */ + #define SSA_OP_VDEF 0x10 /* DEF portion of VDEFS. */ + + /* These are commonly grouped operand flags. */ + #define SSA_OP_VIRTUAL_USES (SSA_OP_VUSE | SSA_OP_VMAYUSE) + #define SSA_OP_VIRTUAL_DEFS (SSA_OP_VDEF) + #define SSA_OP_ALL_USES (SSA_OP_VIRTUAL_USES | SSA_OP_USE) + #define SSA_OP_ALL_DEFS (SSA_OP_VIRTUAL_DEFS | SSA_OP_DEF) + #define SSA_OP_ALL_OPERANDS (SSA_OP_ALL_USES | SSA_OP_ALL_DEFS) + + So if you want to look at the use pointers for all the `USE' and +`VUSE' operands, you would do something like: + + use_operand_p use_p; + ssa_op_iter iter; + + FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, (SSA_OP_USE | SSA_OP_VUSE)) + { + process_use_ptr (use_p); + } + + The `TREE' macro is basically the same as the `USE' and `DEF' macros, +only with the use or def dereferenced via `USE_FROM_PTR (use_p)' and +`DEF_FROM_PTR (def_p)'. Since we aren't using operand pointers, use +and defs flags can be mixed. + + tree var; + ssa_op_iter iter; + + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_VUSE) + { + print_generic_expr (stderr, var, TDF_SLIM); + } + + `VDEF's are broken into two flags, one for the `DEF' portion +(`SSA_OP_VDEF') and one for the USE portion (`SSA_OP_VMAYUSE'). If all +you want to look at are the `VDEF's together, there is a fourth +iterator macro for this, which returns both a def_operand_p and a +use_operand_p for each `VDEF' in the statement. Note that you don't +need any flags for this one. + + use_operand_p use_p; + def_operand_p def_p; + ssa_op_iter iter; + + FOR_EACH_SSA_MAYDEF_OPERAND (def_p, use_p, stmt, iter) + { + my_code; + } + + There are many examples in the code as well, as well as the +documentation in `tree-ssa-operands.h'. + + There are also a couple of variants on the stmt iterators regarding PHI +nodes. + + `FOR_EACH_PHI_ARG' Works exactly like `FOR_EACH_SSA_USE_OPERAND', +except it works over `PHI' arguments instead of statement operands. + + /* Look at every virtual PHI use. */ + FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_VIRTUAL_USES) + { + my_code; + } + + /* Look at every real PHI use. */ + FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_USES) + my_code; + + /* Look at every PHI use. */ + FOR_EACH_PHI_ARG (use_p, phi_stmt, iter, SSA_OP_ALL_USES) + my_code; + + `FOR_EACH_PHI_OR_STMT_{USE,DEF}' works exactly like +`FOR_EACH_SSA_{USE,DEF}_OPERAND', except it will function on either a +statement or a `PHI' node. These should be used when it is appropriate +but they are not quite as efficient as the individual `FOR_EACH_PHI' +and `FOR_EACH_SSA' routines. + + FOR_EACH_PHI_OR_STMT_USE (use_operand_p, stmt, iter, flags) + { + my_code; + } + + FOR_EACH_PHI_OR_STMT_DEF (def_operand_p, phi, iter, flags) + { + my_code; + } + +13.2.2 Immediate Uses +--------------------- + +Immediate use information is now always available. Using the immediate +use iterators, you may examine every use of any `SSA_NAME'. For +instance, to change each use of `ssa_var' to `ssa_var2' and call +fold_stmt on each stmt after that is done: + + use_operand_p imm_use_p; + imm_use_iterator iterator; + tree ssa_var, stmt; + + + FOR_EACH_IMM_USE_STMT (stmt, iterator, ssa_var) + { + FOR_EACH_IMM_USE_ON_STMT (imm_use_p, iterator) + SET_USE (imm_use_p, ssa_var_2); + fold_stmt (stmt); + } + + There are 2 iterators which can be used. `FOR_EACH_IMM_USE_FAST' is +used when the immediate uses are not changed, i.e., you are looking at +the uses, but not setting them. + + If they do get changed, then care must be taken that things are not +changed under the iterators, so use the `FOR_EACH_IMM_USE_STMT' and +`FOR_EACH_IMM_USE_ON_STMT' iterators. They attempt to preserve the +sanity of the use list by moving all the uses for a statement into a +controlled position, and then iterating over those uses. Then the +optimization can manipulate the stmt when all the uses have been +processed. This is a little slower than the FAST version since it adds +a placeholder element and must sort through the list a bit for each +statement. This placeholder element must be also be removed if the +loop is terminated early. The macro `BREAK_FROM_IMM_USE_SAFE' is +provided to do this : + + FOR_EACH_IMM_USE_STMT (stmt, iterator, ssa_var) + { + if (stmt == last_stmt) + BREAK_FROM_SAFE_IMM_USE (iter); + + FOR_EACH_IMM_USE_ON_STMT (imm_use_p, iterator) + SET_USE (imm_use_p, ssa_var_2); + fold_stmt (stmt); + } + + There are checks in `verify_ssa' which verify that the immediate use +list is up to date, as well as checking that an optimization didn't +break from the loop without using this macro. It is safe to simply +'break'; from a `FOR_EACH_IMM_USE_FAST' traverse. + + Some useful functions and macros: + 1. `has_zero_uses (ssa_var)' : Returns true if there are no uses of + `ssa_var'. + + 2. `has_single_use (ssa_var)' : Returns true if there is only a + single use of `ssa_var'. + + 3. `single_imm_use (ssa_var, use_operand_p *ptr, tree *stmt)' : + Returns true if there is only a single use of `ssa_var', and also + returns the use pointer and statement it occurs in, in the second + and third parameters. + + 4. `num_imm_uses (ssa_var)' : Returns the number of immediate uses of + `ssa_var'. It is better not to use this if possible since it simply + utilizes a loop to count the uses. + + 5. `PHI_ARG_INDEX_FROM_USE (use_p)' : Given a use within a `PHI' + node, return the index number for the use. An assert is triggered + if the use isn't located in a `PHI' node. + + 6. `USE_STMT (use_p)' : Return the statement a use occurs in. + + Note that uses are not put into an immediate use list until their +statement is actually inserted into the instruction stream via a +`bsi_*' routine. + + It is also still possible to utilize lazy updating of statements, but +this should be used only when absolutely required. Both alias analysis +and the dominator optimizations currently do this. + + When lazy updating is being used, the immediate use information is out +of date and cannot be used reliably. Lazy updating is achieved by +simply marking statements modified via calls to `mark_stmt_modified' +instead of `update_stmt'. When lazy updating is no longer required, +all the modified statements must have `update_stmt' called in order to +bring them up to date. This must be done before the optimization is +finished, or `verify_ssa' will trigger an abort. + + This is done with a simple loop over the instruction stream: + block_stmt_iterator bsi; + basic_block bb; + FOR_EACH_BB (bb) + { + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + update_stmt_if_modified (bsi_stmt (bsi)); + } + + +File: gccint.info, Node: SSA, Next: Alias analysis, Prev: SSA Operands, Up: Tree SSA + +13.3 Static Single Assignment +============================= + +Most of the tree optimizers rely on the data flow information provided +by the Static Single Assignment (SSA) form. We implement the SSA form +as described in `R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. +Zadeck. Efficiently Computing Static Single Assignment Form and the +Control Dependence Graph. ACM Transactions on Programming Languages +and Systems, 13(4):451-490, October 1991'. + + The SSA form is based on the premise that program variables are +assigned in exactly one location in the program. Multiple assignments +to the same variable create new versions of that variable. Naturally, +actual programs are seldom in SSA form initially because variables tend +to be assigned multiple times. The compiler modifies the program +representation so that every time a variable is assigned in the code, a +new version of the variable is created. Different versions of the same +variable are distinguished by subscripting the variable name with its +version number. Variables used in the right-hand side of expressions +are renamed so that their version number matches that of the most +recent assignment. + + We represent variable versions using `SSA_NAME' nodes. The renaming +process in `tree-ssa.c' wraps every real and virtual operand with an +`SSA_NAME' node which contains the version number and the statement +that created the `SSA_NAME'. Only definitions and virtual definitions +may create new `SSA_NAME' nodes. + + Sometimes, flow of control makes it impossible to determine the most +recent version of a variable. In these cases, the compiler inserts an +artificial definition for that variable called "PHI function" or "PHI +node". This new definition merges all the incoming versions of the +variable to create a new name for it. For instance, + + if (...) + a_1 = 5; + else if (...) + a_2 = 2; + else + a_3 = 13; + + # a_4 = PHI <a_1, a_2, a_3> + return a_4; + + Since it is not possible to determine which of the three branches will +be taken at runtime, we don't know which of `a_1', `a_2' or `a_3' to +use at the return statement. So, the SSA renamer creates a new version +`a_4' which is assigned the result of "merging" `a_1', `a_2' and `a_3'. +Hence, PHI nodes mean "one of these operands. I don't know which". + + The following macros can be used to examine PHI nodes + + -- Macro: PHI_RESULT (PHI) + Returns the `SSA_NAME' created by PHI node PHI (i.e., PHI's LHS). + + -- Macro: PHI_NUM_ARGS (PHI) + Returns the number of arguments in PHI. This number is exactly + the number of incoming edges to the basic block holding PHI. + + -- Macro: PHI_ARG_ELT (PHI, I) + Returns a tuple representing the Ith argument of PHI. Each + element of this tuple contains an `SSA_NAME' VAR and the incoming + edge through which VAR flows. + + -- Macro: PHI_ARG_EDGE (PHI, I) + Returns the incoming edge for the Ith argument of PHI. + + -- Macro: PHI_ARG_DEF (PHI, I) + Returns the `SSA_NAME' for the Ith argument of PHI. + +13.3.1 Preserving the SSA form +------------------------------ + +Some optimization passes make changes to the function that invalidate +the SSA property. This can happen when a pass has added new symbols or +changed the program so that variables that were previously aliased +aren't anymore. Whenever something like this happens, the affected +symbols must be renamed into SSA form again. Transformations that emit +new code or replicate existing statements will also need to update the +SSA form. + + Since GCC implements two different SSA forms for register and virtual +variables, keeping the SSA form up to date depends on whether you are +updating register or virtual names. In both cases, the general idea +behind incremental SSA updates is similar: when new SSA names are +created, they typically are meant to replace other existing names in +the program. + + For instance, given the following code: + + 1 L0: + 2 x_1 = PHI (0, x_5) + 3 if (x_1 < 10) + 4 if (x_1 > 7) + 5 y_2 = 0 + 6 else + 7 y_3 = x_1 + x_7 + 8 endif + 9 x_5 = x_1 + 1 + 10 goto L0; + 11 endif + + Suppose that we insert new names `x_10' and `x_11' (lines `4' and `8'). + + 1 L0: + 2 x_1 = PHI (0, x_5) + 3 if (x_1 < 10) + 4 x_10 = ... + 5 if (x_1 > 7) + 6 y_2 = 0 + 7 else + 8 x_11 = ... + 9 y_3 = x_1 + x_7 + 10 endif + 11 x_5 = x_1 + 1 + 12 goto L0; + 13 endif + + We want to replace all the uses of `x_1' with the new definitions of +`x_10' and `x_11'. Note that the only uses that should be replaced are +those at lines `5', `9' and `11'. Also, the use of `x_7' at line `9' +should _not_ be replaced (this is why we cannot just mark symbol `x' for +renaming). + + Additionally, we may need to insert a PHI node at line `11' because +that is a merge point for `x_10' and `x_11'. So the use of `x_1' at +line `11' will be replaced with the new PHI node. The insertion of PHI +nodes is optional. They are not strictly necessary to preserve the SSA +form, and depending on what the caller inserted, they may not even be +useful for the optimizers. + + Updating the SSA form is a two step process. First, the pass has to +identify which names need to be updated and/or which symbols need to be +renamed into SSA form for the first time. When new names are +introduced to replace existing names in the program, the mapping +between the old and the new names are registered by calling +`register_new_name_mapping' (note that if your pass creates new code by +duplicating basic blocks, the call to `tree_duplicate_bb' will set up +the necessary mappings automatically). On the other hand, if your pass +exposes a new symbol that should be put in SSA form for the first time, +the new symbol should be registered with `mark_sym_for_renaming'. + + After the replacement mappings have been registered and new symbols +marked for renaming, a call to `update_ssa' makes the registered +changes. This can be done with an explicit call or by creating `TODO' +flags in the `tree_opt_pass' structure for your pass. There are +several `TODO' flags that control the behavior of `update_ssa': + + * `TODO_update_ssa'. Update the SSA form inserting PHI nodes for + newly exposed symbols and virtual names marked for updating. When + updating real names, only insert PHI nodes for a real name `O_j' + in blocks reached by all the new and old definitions for `O_j'. + If the iterated dominance frontier for `O_j' is not pruned, we may + end up inserting PHI nodes in blocks that have one or more edges + with no incoming definition for `O_j'. This would lead to + uninitialized warnings for `O_j''s symbol. + + * `TODO_update_ssa_no_phi'. Update the SSA form without inserting + any new PHI nodes at all. This is used by passes that have either + inserted all the PHI nodes themselves or passes that need only to + patch use-def and def-def chains for virtuals (e.g., DCE). + + * `TODO_update_ssa_full_phi'. Insert PHI nodes everywhere they are + needed. No pruning of the IDF is done. This is used by passes + that need the PHI nodes for `O_j' even if it means that some + arguments will come from the default definition of `O_j''s symbol + (e.g., `pass_linear_transform'). + + WARNING: If you need to use this flag, chances are that your pass + may be doing something wrong. Inserting PHI nodes for an old name + where not all edges carry a new replacement may lead to silent + codegen errors or spurious uninitialized warnings. + + * `TODO_update_ssa_only_virtuals'. Passes that update the SSA form + on their own may want to delegate the updating of virtual names to + the generic updater. Since FUD chains are easier to maintain, + this simplifies the work they need to do. NOTE: If this flag is + used, any OLD->NEW mappings for real names are explicitly + destroyed and only the symbols marked for renaming are processed. + +13.3.2 Preserving the virtual SSA form +-------------------------------------- + +The virtual SSA form is harder to preserve than the non-virtual SSA form +mainly because the set of virtual operands for a statement may change at +what some would consider unexpected times. In general, statement +modifications should be bracketed between calls to `push_stmt_changes' +and `pop_stmt_changes'. For example, + + munge_stmt (tree stmt) + { + push_stmt_changes (&stmt); + ... rewrite STMT ... + pop_stmt_changes (&stmt); + } + + The call to `push_stmt_changes' saves the current state of the +statement operands and the call to `pop_stmt_changes' compares the +saved state with the current one and does the appropriate symbol +marking for the SSA renamer. + + It is possible to modify several statements at a time, provided that +`push_stmt_changes' and `pop_stmt_changes' are called in LIFO order, as +when processing a stack of statements. + + Additionally, if the pass discovers that it did not need to make +changes to the statement after calling `push_stmt_changes', it can +simply discard the topmost change buffer by calling +`discard_stmt_changes'. This will avoid the expensive operand re-scan +operation and the buffer comparison that determines if symbols need to +be marked for renaming. + +13.3.3 Examining `SSA_NAME' nodes +--------------------------------- + +The following macros can be used to examine `SSA_NAME' nodes + + -- Macro: SSA_NAME_DEF_STMT (VAR) + Returns the statement S that creates the `SSA_NAME' VAR. If S is + an empty statement (i.e., `IS_EMPTY_STMT (S)' returns `true'), it + means that the first reference to this variable is a USE or a VUSE. + + -- Macro: SSA_NAME_VERSION (VAR) + Returns the version number of the `SSA_NAME' object VAR. + +13.3.4 Walking use-def chains +----------------------------- + + -- Tree SSA function: void walk_use_def_chains (VAR, FN, DATA) + Walks use-def chains starting at the `SSA_NAME' node VAR. Calls + function FN at each reaching definition found. Function FN takes + three arguments: VAR, its defining statement (DEF_STMT) and a + generic pointer to whatever state information that FN may want to + maintain (DATA). Function FN is able to stop the walk by + returning `true', otherwise in order to continue the walk, FN + should return `false'. + + Note, that if DEF_STMT is a `PHI' node, the semantics are slightly + different. For each argument ARG of the PHI node, this function + will: + + 1. Walk the use-def chains for ARG. + + 2. Call `FN (ARG, PHI, DATA)'. + + Note how the first argument to FN is no longer the original + variable VAR, but the PHI argument currently being examined. If + FN wants to get at VAR, it should call `PHI_RESULT' (PHI). + +13.3.5 Walking the dominator tree +--------------------------------- + + -- Tree SSA function: void walk_dominator_tree (WALK_DATA, BB) + This function walks the dominator tree for the current CFG calling + a set of callback functions defined in STRUCT DOM_WALK_DATA in + `domwalk.h'. The call back functions you need to define give you + hooks to execute custom code at various points during traversal: + + 1. Once to initialize any local data needed while processing BB + and its children. This local data is pushed into an internal + stack which is automatically pushed and popped as the walker + traverses the dominator tree. + + 2. Once before traversing all the statements in the BB. + + 3. Once for every statement inside BB. + + 4. Once after traversing all the statements and before recursing + into BB's dominator children. + + 5. It then recurses into all the dominator children of BB. + + 6. After recursing into all the dominator children of BB it can, + optionally, traverse every statement in BB again (i.e., + repeating steps 2 and 3). + + 7. Once after walking the statements in BB and BB's dominator + children. At this stage, the block local data stack is + popped. + + +File: gccint.info, Node: Alias analysis, Next: Memory model, Prev: SSA, Up: Tree SSA + +13.4 Alias analysis +=================== + +Alias analysis in GIMPLE SSA form consists of two pieces. First the +virtual SSA web ties conflicting memory accesses and provides a SSA +use-def chain and SSA immediate-use chains for walking possibly +dependent memory accesses. Second an alias-oracle can be queried to +disambiguate explicit and implicit memory references. + + 1. Memory SSA form. + + All statements that may use memory have exactly one accompanied + use of a virtual SSA name that represents the state of memory at + the given point in the IL. + + All statements that may define memory have exactly one accompanied + definition of a virtual SSA name using the previous state of memory + and defining the new state of memory after the given point in the + IL. + + int i; + int foo (void) + { + # .MEM_3 = VDEF <.MEM_2(D)> + i = 1; + # VUSE <.MEM_3> + return i; + } + + The virtual SSA names in this case are `.MEM_2(D)' and `.MEM_3'. + The store to the global variable `i' defines `.MEM_3' invalidating + `.MEM_2(D)'. The load from `i' uses that new state `.MEM_3'. + + The virtual SSA web serves as constraints to SSA optimizers + preventing illegitimate code-motion and optimization. It also + provides a way to walk related memory statements. + + 2. Points-to and escape analysis. + + Points-to analysis builds a set of constraints from the GIMPLE SSA + IL representing all pointer operations and facts we do or do not + know about pointers. Solving this set of constraints yields a + conservatively correct solution for each pointer variable in the + program (though we are only interested in SSA name pointers) as to + what it may possibly point to. + + This points-to solution for a given SSA name pointer is stored in + the `pt_solution' sub-structure of the `SSA_NAME_PTR_INFO' record. + The following accessor functions are available: + + * `pt_solution_includes' + + * `pt_solutions_intersect' + + Points-to analysis also computes the solution for two special set + of pointers, `ESCAPED' and `CALLUSED'. Those represent all memory + that has escaped the scope of analysis or that is used by pure or + nested const calls. + + 3. Type-based alias analysis + + Type-based alias analysis is frontend dependent though generic + support is provided by the middle-end in `alias.c'. TBAA code is + used by both tree optimizers and RTL optimizers. + + Every language that wishes to perform language-specific alias + analysis should define a function that computes, given a `tree' + node, an alias set for the node. Nodes in different alias sets + are not allowed to alias. For an example, see the C front-end + function `c_get_alias_set'. + + 4. Tree alias-oracle + + The tree alias-oracle provides means to disambiguate two memory + references and memory references against statements. The following + queries are available: + + * `refs_may_alias_p' + + * `ref_maybe_used_by_stmt_p' + + * `stmt_may_clobber_ref_p' + + In addition to those two kind of statement walkers are available + walking statements related to a reference ref. + `walk_non_aliased_vuses' walks over dominating memory defining + statements and calls back if the statement does not clobber ref + providing the non-aliased VUSE. The walk stops at the first + clobbering statement or if asked to. `walk_aliased_vdefs' walks + over dominating memory defining statements and calls back on each + statement clobbering ref providing its aliasing VDEF. The walk + stops if asked to. + + + +File: gccint.info, Node: Memory model, Prev: Alias analysis, Up: Tree SSA + +13.5 Memory model +================= + +The memory model used by the middle-end models that of the C/C++ +languages. The middle-end has the notion of an effective type of a +memory region which is used for type-based alias analysis. + + The following is a refinement of ISO C99 6.5/6, clarifying the block +copy case to follow common sense and extending the concept of a dynamic +effective type to objects with a declared type as required for C++. + + The effective type of an object for an access to its stored value is + the declared type of the object or the effective type determined by + a previous store to it. If a value is stored into an object through + an lvalue having a type that is not a character type, then the + type of the lvalue becomes the effective type of the object for that + access and for subsequent accesses that do not modify the stored value. + If a value is copied into an object using `memcpy' or `memmove', + or is copied as an array of character type, then the effective type + of the modified object for that access and for subsequent accesses that + do not modify the value is undetermined. For all other accesses to an + object, the effective type of the object is simply the type of the + lvalue used for the access. + + +File: gccint.info, Node: Loop Analysis and Representation, Next: Machine Desc, Prev: Control Flow, Up: Top + +14 Analysis and Representation of Loops +*************************************** + +GCC provides extensive infrastructure for work with natural loops, i.e., +strongly connected components of CFG with only one entry block. This +chapter describes representation of loops in GCC, both on GIMPLE and in +RTL, as well as the interfaces to loop-related analyses (induction +variable analysis and number of iterations analysis). + +* Menu: + +* Loop representation:: Representation and analysis of loops. +* Loop querying:: Getting information about loops. +* Loop manipulation:: Loop manipulation functions. +* LCSSA:: Loop-closed SSA form. +* Scalar evolutions:: Induction variables on GIMPLE. +* loop-iv:: Induction variables on RTL. +* Number of iterations:: Number of iterations analysis. +* Dependency analysis:: Data dependency analysis. +* Lambda:: Linear loop transformations framework. +* Omega:: A solver for linear programming problems. + + +File: gccint.info, Node: Loop representation, Next: Loop querying, Up: Loop Analysis and Representation + +14.1 Loop representation +======================== + +This chapter describes the representation of loops in GCC, and functions +that can be used to build, modify and analyze this representation. Most +of the interfaces and data structures are declared in `cfgloop.h'. At +the moment, loop structures are analyzed and this information is +updated only by the optimization passes that deal with loops, but some +efforts are being made to make it available throughout most of the +optimization passes. + + In general, a natural loop has one entry block (header) and possibly +several back edges (latches) leading to the header from the inside of +the loop. Loops with several latches may appear if several loops share +a single header, or if there is a branching in the middle of the loop. +The representation of loops in GCC however allows only loops with a +single latch. During loop analysis, headers of such loops are split and +forwarder blocks are created in order to disambiguate their structures. +Heuristic based on profile information and structure of the induction +variables in the loops is used to determine whether the latches +correspond to sub-loops or to control flow in a single loop. This means +that the analysis sometimes changes the CFG, and if you run it in the +middle of an optimization pass, you must be able to deal with the new +blocks. You may avoid CFG changes by passing +`LOOPS_MAY_HAVE_MULTIPLE_LATCHES' flag to the loop discovery, note +however that most other loop manipulation functions will not work +correctly for loops with multiple latch edges (the functions that only +query membership of blocks to loops and subloop relationships, or +enumerate and test loop exits, can be expected to work). + + Body of the loop is the set of blocks that are dominated by its header, +and reachable from its latch against the direction of edges in CFG. The +loops are organized in a containment hierarchy (tree) such that all the +loops immediately contained inside loop L are the children of L in the +tree. This tree is represented by the `struct loops' structure. The +root of this tree is a fake loop that contains all blocks in the +function. Each of the loops is represented in a `struct loop' +structure. Each loop is assigned an index (`num' field of the `struct +loop' structure), and the pointer to the loop is stored in the +corresponding field of the `larray' vector in the loops structure. The +indices do not have to be continuous, there may be empty (`NULL') +entries in the `larray' created by deleting loops. Also, there is no +guarantee on the relative order of a loop and its subloops in the +numbering. The index of a loop never changes. + + The entries of the `larray' field should not be accessed directly. +The function `get_loop' returns the loop description for a loop with +the given index. `number_of_loops' function returns number of loops in +the function. To traverse all loops, use `FOR_EACH_LOOP' macro. The +`flags' argument of the macro is used to determine the direction of +traversal and the set of loops visited. Each loop is guaranteed to be +visited exactly once, regardless of the changes to the loop tree, and +the loops may be removed during the traversal. The newly created loops +are never traversed, if they need to be visited, this must be done +separately after their creation. The `FOR_EACH_LOOP' macro allocates +temporary variables. If the `FOR_EACH_LOOP' loop were ended using +break or goto, they would not be released; `FOR_EACH_LOOP_BREAK' macro +must be used instead. + + Each basic block contains the reference to the innermost loop it +belongs to (`loop_father'). For this reason, it is only possible to +have one `struct loops' structure initialized at the same time for each +CFG. The global variable `current_loops' contains the `struct loops' +structure. Many of the loop manipulation functions assume that +dominance information is up-to-date. + + The loops are analyzed through `loop_optimizer_init' function. The +argument of this function is a set of flags represented in an integer +bitmask. These flags specify what other properties of the loop +structures should be calculated/enforced and preserved later: + + * `LOOPS_MAY_HAVE_MULTIPLE_LATCHES': If this flag is set, no changes + to CFG will be performed in the loop analysis, in particular, + loops with multiple latch edges will not be disambiguated. If a + loop has multiple latches, its latch block is set to NULL. Most of + the loop manipulation functions will not work for loops in this + shape. No other flags that require CFG changes can be passed to + loop_optimizer_init. + + * `LOOPS_HAVE_PREHEADERS': Forwarder blocks are created in such a + way that each loop has only one entry edge, and additionally, the + source block of this entry edge has only one successor. This + creates a natural place where the code can be moved out of the + loop, and ensures that the entry edge of the loop leads from its + immediate super-loop. + + * `LOOPS_HAVE_SIMPLE_LATCHES': Forwarder blocks are created to force + the latch block of each loop to have only one successor. This + ensures that the latch of the loop does not belong to any of its + sub-loops, and makes manipulation with the loops significantly + easier. Most of the loop manipulation functions assume that the + loops are in this shape. Note that with this flag, the "normal" + loop without any control flow inside and with one exit consists of + two basic blocks. + + * `LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS': Basic blocks and edges in + the strongly connected components that are not natural loops (have + more than one entry block) are marked with `BB_IRREDUCIBLE_LOOP' + and `EDGE_IRREDUCIBLE_LOOP' flags. The flag is not set for blocks + and edges that belong to natural loops that are in such an + irreducible region (but it is set for the entry and exit edges of + such a loop, if they lead to/from this region). + + * `LOOPS_HAVE_RECORDED_EXITS': The lists of exits are recorded and + updated for each loop. This makes some functions (e.g., + `get_loop_exit_edges') more efficient. Some functions (e.g., + `single_exit') can be used only if the lists of exits are recorded. + + These properties may also be computed/enforced later, using functions +`create_preheaders', `force_single_succ_latches', +`mark_irreducible_loops' and `record_loop_exits'. + + The memory occupied by the loops structures should be freed with +`loop_optimizer_finalize' function. + + The CFG manipulation functions in general do not update loop +structures. Specialized versions that additionally do so are provided +for the most common tasks. On GIMPLE, `cleanup_tree_cfg_loop' function +can be used to cleanup CFG while updating the loops structures if +`current_loops' is set. + + +File: gccint.info, Node: Loop querying, Next: Loop manipulation, Prev: Loop representation, Up: Loop Analysis and Representation + +14.2 Loop querying +================== + +The functions to query the information about loops are declared in +`cfgloop.h'. Some of the information can be taken directly from the +structures. `loop_father' field of each basic block contains the +innermost loop to that the block belongs. The most useful fields of +loop structure (that are kept up-to-date at all times) are: + + * `header', `latch': Header and latch basic blocks of the loop. + + * `num_nodes': Number of basic blocks in the loop (including the + basic blocks of the sub-loops). + + * `depth': The depth of the loop in the loops tree, i.e., the number + of super-loops of the loop. + + * `outer', `inner', `next': The super-loop, the first sub-loop, and + the sibling of the loop in the loops tree. + + There are other fields in the loop structures, many of them used only +by some of the passes, or not updated during CFG changes; in general, +they should not be accessed directly. + + The most important functions to query loop structures are: + + * `flow_loops_dump': Dumps the information about loops to a file. + + * `verify_loop_structure': Checks consistency of the loop structures. + + * `loop_latch_edge': Returns the latch edge of a loop. + + * `loop_preheader_edge': If loops have preheaders, returns the + preheader edge of a loop. + + * `flow_loop_nested_p': Tests whether loop is a sub-loop of another + loop. + + * `flow_bb_inside_loop_p': Tests whether a basic block belongs to a + loop (including its sub-loops). + + * `find_common_loop': Finds the common super-loop of two loops. + + * `superloop_at_depth': Returns the super-loop of a loop with the + given depth. + + * `tree_num_loop_insns', `num_loop_insns': Estimates the number of + insns in the loop, on GIMPLE and on RTL. + + * `loop_exit_edge_p': Tests whether edge is an exit from a loop. + + * `mark_loop_exit_edges': Marks all exit edges of all loops with + `EDGE_LOOP_EXIT' flag. + + * `get_loop_body', `get_loop_body_in_dom_order', + `get_loop_body_in_bfs_order': Enumerates the basic blocks in the + loop in depth-first search order in reversed CFG, ordered by + dominance relation, and breath-first search order, respectively. + + * `single_exit': Returns the single exit edge of the loop, or `NULL' + if the loop has more than one exit. You can only use this + function if LOOPS_HAVE_MARKED_SINGLE_EXITS property is used. + + * `get_loop_exit_edges': Enumerates the exit edges of a loop. + + * `just_once_each_iteration_p': Returns true if the basic block is + executed exactly once during each iteration of a loop (that is, it + does not belong to a sub-loop, and it dominates the latch of the + loop). + + +File: gccint.info, Node: Loop manipulation, Next: LCSSA, Prev: Loop querying, Up: Loop Analysis and Representation + +14.3 Loop manipulation +====================== + +The loops tree can be manipulated using the following functions: + + * `flow_loop_tree_node_add': Adds a node to the tree. + + * `flow_loop_tree_node_remove': Removes a node from the tree. + + * `add_bb_to_loop': Adds a basic block to a loop. + + * `remove_bb_from_loops': Removes a basic block from loops. + + Most low-level CFG functions update loops automatically. The following +functions handle some more complicated cases of CFG manipulations: + + * `remove_path': Removes an edge and all blocks it dominates. + + * `split_loop_exit_edge': Splits exit edge of the loop, ensuring + that PHI node arguments remain in the loop (this ensures that + loop-closed SSA form is preserved). Only useful on GIMPLE. + + Finally, there are some higher-level loop transformations implemented. +While some of them are written so that they should work on non-innermost +loops, they are mostly untested in that case, and at the moment, they +are only reliable for the innermost loops: + + * `create_iv': Creates a new induction variable. Only works on + GIMPLE. `standard_iv_increment_position' can be used to find a + suitable place for the iv increment. + + * `duplicate_loop_to_header_edge', + `tree_duplicate_loop_to_header_edge': These functions (on RTL and + on GIMPLE) duplicate the body of the loop prescribed number of + times on one of the edges entering loop header, thus performing + either loop unrolling or loop peeling. `can_duplicate_loop_p' + (`can_unroll_loop_p' on GIMPLE) must be true for the duplicated + loop. + + * `loop_version', `tree_ssa_loop_version': These function create a + copy of a loop, and a branch before them that selects one of them + depending on the prescribed condition. This is useful for + optimizations that need to verify some assumptions in runtime (one + of the copies of the loop is usually left unchanged, while the + other one is transformed in some way). + + * `tree_unroll_loop': Unrolls the loop, including peeling the extra + iterations to make the number of iterations divisible by unroll + factor, updating the exit condition, and removing the exits that + now cannot be taken. Works only on GIMPLE. + + +File: gccint.info, Node: LCSSA, Next: Scalar evolutions, Prev: Loop manipulation, Up: Loop Analysis and Representation + +14.4 Loop-closed SSA form +========================= + +Throughout the loop optimizations on tree level, one extra condition is +enforced on the SSA form: No SSA name is used outside of the loop in +that it is defined. The SSA form satisfying this condition is called +"loop-closed SSA form" - LCSSA. To enforce LCSSA, PHI nodes must be +created at the exits of the loops for the SSA names that are used +outside of them. Only the real operands (not virtual SSA names) are +held in LCSSA, in order to save memory. + + There are various benefits of LCSSA: + + * Many optimizations (value range analysis, final value replacement) + are interested in the values that are defined in the loop and used + outside of it, i.e., exactly those for that we create new PHI + nodes. + + * In induction variable analysis, it is not necessary to specify the + loop in that the analysis should be performed - the scalar + evolution analysis always returns the results with respect to the + loop in that the SSA name is defined. + + * It makes updating of SSA form during loop transformations simpler. + Without LCSSA, operations like loop unrolling may force creation + of PHI nodes arbitrarily far from the loop, while in LCSSA, the + SSA form can be updated locally. However, since we only keep real + operands in LCSSA, we cannot use this advantage (we could have + local updating of real operands, but it is not much more efficient + than to use generic SSA form updating for it as well; the amount + of changes to SSA is the same). + + However, it also means LCSSA must be updated. This is usually +straightforward, unless you create a new value in loop and use it +outside, or unless you manipulate loop exit edges (functions are +provided to make these manipulations simple). +`rewrite_into_loop_closed_ssa' is used to rewrite SSA form to LCSSA, +and `verify_loop_closed_ssa' to check that the invariant of LCSSA is +preserved. + + +File: gccint.info, Node: Scalar evolutions, Next: loop-iv, Prev: LCSSA, Up: Loop Analysis and Representation + +14.5 Scalar evolutions +====================== + +Scalar evolutions (SCEV) are used to represent results of induction +variable analysis on GIMPLE. They enable us to represent variables with +complicated behavior in a simple and consistent way (we only use it to +express values of polynomial induction variables, but it is possible to +extend it). The interfaces to SCEV analysis are declared in +`tree-scalar-evolution.h'. To use scalar evolutions analysis, +`scev_initialize' must be used. To stop using SCEV, `scev_finalize' +should be used. SCEV analysis caches results in order to save time and +memory. This cache however is made invalid by most of the loop +transformations, including removal of code. If such a transformation +is performed, `scev_reset' must be called to clean the caches. + + Given an SSA name, its behavior in loops can be analyzed using the +`analyze_scalar_evolution' function. The returned SCEV however does +not have to be fully analyzed and it may contain references to other +SSA names defined in the loop. To resolve these (potentially +recursive) references, `instantiate_parameters' or `resolve_mixers' +functions must be used. `instantiate_parameters' is useful when you +use the results of SCEV only for some analysis, and when you work with +whole nest of loops at once. It will try replacing all SSA names by +their SCEV in all loops, including the super-loops of the current loop, +thus providing a complete information about the behavior of the +variable in the loop nest. `resolve_mixers' is useful if you work with +only one loop at a time, and if you possibly need to create code based +on the value of the induction variable. It will only resolve the SSA +names defined in the current loop, leaving the SSA names defined +outside unchanged, even if their evolution in the outer loops is known. + + The SCEV is a normal tree expression, except for the fact that it may +contain several special tree nodes. One of them is `SCEV_NOT_KNOWN', +used for SSA names whose value cannot be expressed. The other one is +`POLYNOMIAL_CHREC'. Polynomial chrec has three arguments - base, step +and loop (both base and step may contain further polynomial chrecs). +Type of the expression and of base and step must be the same. A +variable has evolution `POLYNOMIAL_CHREC(base, step, loop)' if it is +(in the specified loop) equivalent to `x_1' in the following example + + while (...) + { + x_1 = phi (base, x_2); + x_2 = x_1 + step; + } + + Note that this includes the language restrictions on the operations. +For example, if we compile C code and `x' has signed type, then the +overflow in addition would cause undefined behavior, and we may assume +that this does not happen. Hence, the value with this SCEV cannot +overflow (which restricts the number of iterations of such a loop). + + In many cases, one wants to restrict the attention just to affine +induction variables. In this case, the extra expressive power of SCEV +is not useful, and may complicate the optimizations. In this case, +`simple_iv' function may be used to analyze a value - the result is a +loop-invariant base and step. + + +File: gccint.info, Node: loop-iv, Next: Number of iterations, Prev: Scalar evolutions, Up: Loop Analysis and Representation + +14.6 IV analysis on RTL +======================= + +The induction variable on RTL is simple and only allows analysis of +affine induction variables, and only in one loop at once. The interface +is declared in `cfgloop.h'. Before analyzing induction variables in a +loop L, `iv_analysis_loop_init' function must be called on L. After +the analysis (possibly calling `iv_analysis_loop_init' for several +loops) is finished, `iv_analysis_done' should be called. The following +functions can be used to access the results of the analysis: + + * `iv_analyze': Analyzes a single register used in the given insn. + If no use of the register in this insn is found, the following + insns are scanned, so that this function can be called on the insn + returned by get_condition. + + * `iv_analyze_result': Analyzes result of the assignment in the + given insn. + + * `iv_analyze_expr': Analyzes a more complicated expression. All + its operands are analyzed by `iv_analyze', and hence they must be + used in the specified insn or one of the following insns. + + The description of the induction variable is provided in `struct +rtx_iv'. In order to handle subregs, the representation is a bit +complicated; if the value of the `extend' field is not `UNKNOWN', the +value of the induction variable in the i-th iteration is + + delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)), + + with the following exception: if `first_special' is true, then the +value in the first iteration (when `i' is zero) is `delta + mult * +base'. However, if `extend' is equal to `UNKNOWN', then +`first_special' must be false, `delta' 0, `mult' 1 and the value in the +i-th iteration is + + subreg_{mode} (base + i * step) + + The function `get_iv_value' can be used to perform these calculations. + + +File: gccint.info, Node: Number of iterations, Next: Dependency analysis, Prev: loop-iv, Up: Loop Analysis and Representation + +14.7 Number of iterations analysis +================================== + +Both on GIMPLE and on RTL, there are functions available to determine +the number of iterations of a loop, with a similar interface. The +number of iterations of a loop in GCC is defined as the number of +executions of the loop latch. In many cases, it is not possible to +determine the number of iterations unconditionally - the determined +number is correct only if some assumptions are satisfied. The analysis +tries to verify these conditions using the information contained in the +program; if it fails, the conditions are returned together with the +result. The following information and conditions are provided by the +analysis: + + * `assumptions': If this condition is false, the rest of the + information is invalid. + + * `noloop_assumptions' on RTL, `may_be_zero' on GIMPLE: If this + condition is true, the loop exits in the first iteration. + + * `infinite': If this condition is true, the loop is infinite. This + condition is only available on RTL. On GIMPLE, conditions for + finiteness of the loop are included in `assumptions'. + + * `niter_expr' on RTL, `niter' on GIMPLE: The expression that gives + number of iterations. The number of iterations is defined as the + number of executions of the loop latch. + + Both on GIMPLE and on RTL, it necessary for the induction variable +analysis framework to be initialized (SCEV on GIMPLE, loop-iv on RTL). +On GIMPLE, the results are stored to `struct tree_niter_desc' +structure. Number of iterations before the loop is exited through a +given exit can be determined using `number_of_iterations_exit' +function. On RTL, the results are returned in `struct niter_desc' +structure. The corresponding function is named `check_simple_exit'. +There are also functions that pass through all the exits of a loop and +try to find one with easy to determine number of iterations - +`find_loop_niter' on GIMPLE and `find_simple_exit' on RTL. Finally, +there are functions that provide the same information, but additionally +cache it, so that repeated calls to number of iterations are not so +costly - `number_of_latch_executions' on GIMPLE and +`get_simple_loop_desc' on RTL. + + Note that some of these functions may behave slightly differently than +others - some of them return only the expression for the number of +iterations, and fail if there are some assumptions. The function +`number_of_latch_executions' works only for single-exit loops. The +function `number_of_cond_exit_executions' can be used to determine +number of executions of the exit condition of a single-exit loop (i.e., +the `number_of_latch_executions' increased by one). + + +File: gccint.info, Node: Dependency analysis, Next: Lambda, Prev: Number of iterations, Up: Loop Analysis and Representation + +14.8 Data Dependency Analysis +============================= + +The code for the data dependence analysis can be found in +`tree-data-ref.c' and its interface and data structures are described +in `tree-data-ref.h'. The function that computes the data dependences +for all the array and pointer references for a given loop is +`compute_data_dependences_for_loop'. This function is currently used +by the linear loop transform and the vectorization passes. Before +calling this function, one has to allocate two vectors: a first vector +will contain the set of data references that are contained in the +analyzed loop body, and the second vector will contain the dependence +relations between the data references. Thus if the vector of data +references is of size `n', the vector containing the dependence +relations will contain `n*n' elements. However if the analyzed loop +contains side effects, such as calls that potentially can interfere +with the data references in the current analyzed loop, the analysis +stops while scanning the loop body for data references, and inserts a +single `chrec_dont_know' in the dependence relation array. + + The data references are discovered in a particular order during the +scanning of the loop body: the loop body is analyzed in execution order, +and the data references of each statement are pushed at the end of the +data reference array. Two data references syntactically occur in the +program in the same order as in the array of data references. This +syntactic order is important in some classical data dependence tests, +and mapping this order to the elements of this array avoids costly +queries to the loop body representation. + + Three types of data references are currently handled: ARRAY_REF, +INDIRECT_REF and COMPONENT_REF. The data structure for the data +reference is `data_reference', where `data_reference_p' is a name of a +pointer to the data reference structure. The structure contains the +following elements: + + * `base_object_info': Provides information about the base object of + the data reference and its access functions. These access functions + represent the evolution of the data reference in the loop relative + to its base, in keeping with the classical meaning of the data + reference access function for the support of arrays. For example, + for a reference `a.b[i][j]', the base object is `a.b' and the + access functions, one for each array subscript, are: `{i_init, + + i_step}_1, {j_init, +, j_step}_2'. + + * `first_location_in_loop': Provides information about the first + location accessed by the data reference in the loop and about the + access function used to represent evolution relative to this + location. This data is used to support pointers, and is not used + for arrays (for which we have base objects). Pointer accesses are + represented as a one-dimensional access that starts from the first + location accessed in the loop. For example: + + for1 i + for2 j + *((int *)p + i + j) = a[i][j]; + + The access function of the pointer access is `{0, + 4B}_for2' + relative to `p + i'. The access functions of the array are + `{i_init, + i_step}_for1' and `{j_init, +, j_step}_for2' relative + to `a'. + + Usually, the object the pointer refers to is either unknown, or we + can't prove that the access is confined to the boundaries of a + certain object. + + Two data references can be compared only if at least one of these + two representations has all its fields filled for both data + references. + + The current strategy for data dependence tests is as follows: If + both `a' and `b' are represented as arrays, compare + `a.base_object' and `b.base_object'; if they are equal, apply + dependence tests (use access functions based on base_objects). + Else if both `a' and `b' are represented as pointers, compare + `a.first_location' and `b.first_location'; if they are equal, + apply dependence tests (use access functions based on first + location). However, if `a' and `b' are represented differently, + only try to prove that the bases are definitely different. + + * Aliasing information. + + * Alignment information. + + The structure describing the relation between two data references is +`data_dependence_relation' and the shorter name for a pointer to such a +structure is `ddr_p'. This structure contains: + + * a pointer to each data reference, + + * a tree node `are_dependent' that is set to `chrec_known' if the + analysis has proved that there is no dependence between these two + data references, `chrec_dont_know' if the analysis was not able to + determine any useful result and potentially there could exist a + dependence between these data references, and `are_dependent' is + set to `NULL_TREE' if there exist a dependence relation between the + data references, and the description of this dependence relation is + given in the `subscripts', `dir_vects', and `dist_vects' arrays, + + * a boolean that determines whether the dependence relation can be + represented by a classical distance vector, + + * an array `subscripts' that contains a description of each + subscript of the data references. Given two array accesses a + subscript is the tuple composed of the access functions for a given + dimension. For example, given `A[f1][f2][f3]' and + `B[g1][g2][g3]', there are three subscripts: `(f1, g1), (f2, g2), + (f3, g3)'. + + * two arrays `dir_vects' and `dist_vects' that contain classical + representations of the data dependences under the form of + direction and distance dependence vectors, + + * an array of loops `loop_nest' that contains the loops to which the + distance and direction vectors refer to. + + Several functions for pretty printing the information extracted by the +data dependence analysis are available: `dump_ddrs' prints with a +maximum verbosity the details of a data dependence relations array, +`dump_dist_dir_vectors' prints only the classical distance and +direction vectors for a data dependence relations array, and +`dump_data_references' prints the details of the data references +contained in a data reference array. + + +File: gccint.info, Node: Lambda, Next: Omega, Prev: Dependency analysis, Up: Loop Analysis and Representation + +14.9 Linear loop transformations framework +========================================== + +Lambda is a framework that allows transformations of loops using +non-singular matrix based transformations of the iteration space and +loop bounds. This allows compositions of skewing, scaling, interchange, +and reversal transformations. These transformations are often used to +improve cache behavior or remove inner loop dependencies to allow +parallelization and vectorization to take place. + + To perform these transformations, Lambda requires that the loopnest be +converted into an internal form that can be matrix transformed easily. +To do this conversion, the function `gcc_loopnest_to_lambda_loopnest' +is provided. If the loop cannot be transformed using lambda, this +function will return NULL. + + Once a `lambda_loopnest' is obtained from the conversion function, it +can be transformed by using `lambda_loopnest_transform', which takes a +transformation matrix to apply. Note that it is up to the caller to +verify that the transformation matrix is legal to apply to the loop +(dependence respecting, etc). Lambda simply applies whatever matrix it +is told to provide. It can be extended to make legal matrices out of +any non-singular matrix, but this is not currently implemented. +Legality of a matrix for a given loopnest can be verified using +`lambda_transform_legal_p'. + + Given a transformed loopnest, conversion back into gcc IR is done by +`lambda_loopnest_to_gcc_loopnest'. This function will modify the loops +so that they match the transformed loopnest. + + +File: gccint.info, Node: Omega, Prev: Lambda, Up: Loop Analysis and Representation + +14.10 Omega a solver for linear programming problems +==================================================== + +The data dependence analysis contains several solvers triggered +sequentially from the less complex ones to the more sophisticated. For +ensuring the consistency of the results of these solvers, a data +dependence check pass has been implemented based on two different +solvers. The second method that has been integrated to GCC is based on +the Omega dependence solver, written in the 1990's by William Pugh and +David Wonnacott. Data dependence tests can be formulated using a +subset of the Presburger arithmetics that can be translated to linear +constraint systems. These linear constraint systems can then be solved +using the Omega solver. + + The Omega solver is using Fourier-Motzkin's algorithm for variable +elimination: a linear constraint system containing `n' variables is +reduced to a linear constraint system with `n-1' variables. The Omega +solver can also be used for solving other problems that can be +expressed under the form of a system of linear equalities and +inequalities. The Omega solver is known to have an exponential worst +case, also known under the name of "omega nightmare" in the literature, +but in practice, the omega test is known to be efficient for the common +data dependence tests. + + The interface used by the Omega solver for describing the linear +programming problems is described in `omega.h', and the solver is +`omega_solve_problem'. + + +File: gccint.info, Node: Control Flow, Next: Loop Analysis and Representation, Prev: RTL, Up: Top + +15 Control Flow Graph +********************* + +A control flow graph (CFG) is a data structure built on top of the +intermediate code representation (the RTL or `tree' instruction stream) +abstracting the control flow behavior of a function that is being +compiled. The CFG is a directed graph where the vertices represent +basic blocks and edges represent possible transfer of control flow from +one basic block to another. The data structures used to represent the +control flow graph are defined in `basic-block.h'. + +* Menu: + +* Basic Blocks:: The definition and representation of basic blocks. +* Edges:: Types of edges and their representation. +* Profile information:: Representation of frequencies and probabilities. +* Maintaining the CFG:: Keeping the control flow graph and up to date. +* Liveness information:: Using and maintaining liveness information. + + +File: gccint.info, Node: Basic Blocks, Next: Edges, Up: Control Flow + +15.1 Basic Blocks +================= + +A basic block is a straight-line sequence of code with only one entry +point and only one exit. In GCC, basic blocks are represented using +the `basic_block' data type. + + Two pointer members of the `basic_block' structure are the pointers +`next_bb' and `prev_bb'. These are used to keep doubly linked chain of +basic blocks in the same order as the underlying instruction stream. +The chain of basic blocks is updated transparently by the provided API +for manipulating the CFG. The macro `FOR_EACH_BB' can be used to visit +all the basic blocks in lexicographical order. Dominator traversals +are also possible using `walk_dominator_tree'. Given two basic blocks +A and B, block A dominates block B if A is _always_ executed before B. + + The `BASIC_BLOCK' array contains all basic blocks in an unspecified +order. Each `basic_block' structure has a field that holds a unique +integer identifier `index' that is the index of the block in the +`BASIC_BLOCK' array. The total number of basic blocks in the function +is `n_basic_blocks'. Both the basic block indices and the total number +of basic blocks may vary during the compilation process, as passes +reorder, create, duplicate, and destroy basic blocks. The index for +any block should never be greater than `last_basic_block'. + + Special basic blocks represent possible entry and exit points of a +function. These blocks are called `ENTRY_BLOCK_PTR' and +`EXIT_BLOCK_PTR'. These blocks do not contain any code, and are not +elements of the `BASIC_BLOCK' array. Therefore they have been assigned +unique, negative index numbers. + + Each `basic_block' also contains pointers to the first instruction +(the "head") and the last instruction (the "tail") or "end" of the +instruction stream contained in a basic block. In fact, since the +`basic_block' data type is used to represent blocks in both major +intermediate representations of GCC (`tree' and RTL), there are +pointers to the head and end of a basic block for both representations. + + For RTL, these pointers are `rtx head, end'. In the RTL function +representation, the head pointer always points either to a +`NOTE_INSN_BASIC_BLOCK' or to a `CODE_LABEL', if present. In the RTL +representation of a function, the instruction stream contains not only +the "real" instructions, but also "notes". Any function that moves or +duplicates the basic blocks needs to take care of updating of these +notes. Many of these notes expect that the instruction stream consists +of linear regions, making such updates difficult. The +`NOTE_INSN_BASIC_BLOCK' note is the only kind of note that may appear +in the instruction stream contained in a basic block. The instruction +stream of a basic block always follows a `NOTE_INSN_BASIC_BLOCK', but +zero or more `CODE_LABEL' nodes can precede the block note. A basic +block ends by control flow instruction or last instruction before +following `CODE_LABEL' or `NOTE_INSN_BASIC_BLOCK'. A `CODE_LABEL' +cannot appear in the instruction stream of a basic block. + + In addition to notes, the jump table vectors are also represented as +"pseudo-instructions" inside the insn stream. These vectors never +appear in the basic block and should always be placed just after the +table jump instructions referencing them. After removing the +table-jump it is often difficult to eliminate the code computing the +address and referencing the vector, so cleaning up these vectors is +postponed until after liveness analysis. Thus the jump table vectors +may appear in the insn stream unreferenced and without any purpose. +Before any edge is made "fall-thru", the existence of such construct in +the way needs to be checked by calling `can_fallthru' function. + + For the `tree' representation, the head and end of the basic block are +being pointed to by the `stmt_list' field, but this special `tree' +should never be referenced directly. Instead, at the tree level +abstract containers and iterators are used to access statements and +expressions in basic blocks. These iterators are called "block +statement iterators" (BSIs). Grep for `^bsi' in the various `tree-*' +files. The following snippet will pretty-print all the statements of +the program in the GIMPLE representation. + + FOR_EACH_BB (bb) + { + block_stmt_iterator si; + + for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si)) + { + tree stmt = bsi_stmt (si); + print_generic_stmt (stderr, stmt, 0); + } + } + + +File: gccint.info, Node: Edges, Next: Profile information, Prev: Basic Blocks, Up: Control Flow + +15.2 Edges +========== + +Edges represent possible control flow transfers from the end of some +basic block A to the head of another basic block B. We say that A is a +predecessor of B, and B is a successor of A. Edges are represented in +GCC with the `edge' data type. Each `edge' acts as a link between two +basic blocks: the `src' member of an edge points to the predecessor +basic block of the `dest' basic block. The members `preds' and `succs' +of the `basic_block' data type point to type-safe vectors of edges to +the predecessors and successors of the block. + + When walking the edges in an edge vector, "edge iterators" should be +used. Edge iterators are constructed using the `edge_iterator' data +structure and several methods are available to operate on them: + +`ei_start' + This function initializes an `edge_iterator' that points to the + first edge in a vector of edges. + +`ei_last' + This function initializes an `edge_iterator' that points to the + last edge in a vector of edges. + +`ei_end_p' + This predicate is `true' if an `edge_iterator' represents the last + edge in an edge vector. + +`ei_one_before_end_p' + This predicate is `true' if an `edge_iterator' represents the + second last edge in an edge vector. + +`ei_next' + This function takes a pointer to an `edge_iterator' and makes it + point to the next edge in the sequence. + +`ei_prev' + This function takes a pointer to an `edge_iterator' and makes it + point to the previous edge in the sequence. + +`ei_edge' + This function returns the `edge' currently pointed to by an + `edge_iterator'. + +`ei_safe_safe' + This function returns the `edge' currently pointed to by an + `edge_iterator', but returns `NULL' if the iterator is pointing at + the end of the sequence. This function has been provided for + existing code makes the assumption that a `NULL' edge indicates + the end of the sequence. + + + The convenience macro `FOR_EACH_EDGE' can be used to visit all of the +edges in a sequence of predecessor or successor edges. It must not be +used when an element might be removed during the traversal, otherwise +elements will be missed. Here is an example of how to use the macro: + + edge e; + edge_iterator ei; + + FOR_EACH_EDGE (e, ei, bb->succs) + { + if (e->flags & EDGE_FALLTHRU) + break; + } + + There are various reasons why control flow may transfer from one block +to another. One possibility is that some instruction, for example a +`CODE_LABEL', in a linearized instruction stream just always starts a +new basic block. In this case a "fall-thru" edge links the basic block +to the first following basic block. But there are several other +reasons why edges may be created. The `flags' field of the `edge' data +type is used to store information about the type of edge we are dealing +with. Each edge is of one of the following types: + +_jump_ + No type flags are set for edges corresponding to jump instructions. + These edges are used for unconditional or conditional jumps and in + RTL also for table jumps. They are the easiest to manipulate as + they may be freely redirected when the flow graph is not in SSA + form. + +_fall-thru_ + Fall-thru edges are present in case where the basic block may + continue execution to the following one without branching. These + edges have the `EDGE_FALLTHRU' flag set. Unlike other types of + edges, these edges must come into the basic block immediately + following in the instruction stream. The function + `force_nonfallthru' is available to insert an unconditional jump + in the case that redirection is needed. Note that this may + require creation of a new basic block. + +_exception handling_ + Exception handling edges represent possible control transfers from + a trapping instruction to an exception handler. The definition of + "trapping" varies. In C++, only function calls can throw, but for + Java, exceptions like division by zero or segmentation fault are + defined and thus each instruction possibly throwing this kind of + exception needs to be handled as control flow instruction. + Exception edges have the `EDGE_ABNORMAL' and `EDGE_EH' flags set. + + When updating the instruction stream it is easy to change possibly + trapping instruction to non-trapping, by simply removing the + exception edge. The opposite conversion is difficult, but should + not happen anyway. The edges can be eliminated via + `purge_dead_edges' call. + + In the RTL representation, the destination of an exception edge is + specified by `REG_EH_REGION' note attached to the insn. In case + of a trapping call the `EDGE_ABNORMAL_CALL' flag is set too. In + the `tree' representation, this extra flag is not set. + + In the RTL representation, the predicate `may_trap_p' may be used + to check whether instruction still may trap or not. For the tree + representation, the `tree_could_trap_p' predicate is available, + but this predicate only checks for possible memory traps, as in + dereferencing an invalid pointer location. + +_sibling calls_ + Sibling calls or tail calls terminate the function in a + non-standard way and thus an edge to the exit must be present. + `EDGE_SIBCALL' and `EDGE_ABNORMAL' are set in such case. These + edges only exist in the RTL representation. + +_computed jumps_ + Computed jumps contain edges to all labels in the function + referenced from the code. All those edges have `EDGE_ABNORMAL' + flag set. The edges used to represent computed jumps often cause + compile time performance problems, since functions consisting of + many taken labels and many computed jumps may have _very_ dense + flow graphs, so these edges need to be handled with special care. + During the earlier stages of the compilation process, GCC tries to + avoid such dense flow graphs by factoring computed jumps. For + example, given the following series of jumps, + + goto *x; + [ ... ] + + goto *x; + [ ... ] + + goto *x; + [ ... ] + + factoring the computed jumps results in the following code sequence + which has a much simpler flow graph: + + goto y; + [ ... ] + + goto y; + [ ... ] + + goto y; + [ ... ] + + y: + goto *x; + + However, the classic problem with this transformation is that it + has a runtime cost in there resulting code: An extra jump. + Therefore, the computed jumps are un-factored in the later passes + of the compiler. Be aware of that when you work on passes in that + area. There have been numerous examples already where the compile + time for code with unfactored computed jumps caused some serious + headaches. + +_nonlocal goto handlers_ + GCC allows nested functions to return into caller using a `goto' + to a label passed to as an argument to the callee. The labels + passed to nested functions contain special code to cleanup after + function call. Such sections of code are referred to as "nonlocal + goto receivers". If a function contains such nonlocal goto + receivers, an edge from the call to the label is created with the + `EDGE_ABNORMAL' and `EDGE_ABNORMAL_CALL' flags set. + +_function entry points_ + By definition, execution of function starts at basic block 0, so + there is always an edge from the `ENTRY_BLOCK_PTR' to basic block + 0. There is no `tree' representation for alternate entry points at + this moment. In RTL, alternate entry points are specified by + `CODE_LABEL' with `LABEL_ALTERNATE_NAME' defined. This feature is + currently used for multiple entry point prologues and is limited + to post-reload passes only. This can be used by back-ends to emit + alternate prologues for functions called from different contexts. + In future full support for multiple entry functions defined by + Fortran 90 needs to be implemented. + +_function exits_ + In the pre-reload representation a function terminates after the + last instruction in the insn chain and no explicit return + instructions are used. This corresponds to the fall-thru edge + into exit block. After reload, optimal RTL epilogues are used + that use explicit (conditional) return instructions that are + represented by edges with no flags set. + + + +File: gccint.info, Node: Profile information, Next: Maintaining the CFG, Prev: Edges, Up: Control Flow + +15.3 Profile information +======================== + +In many cases a compiler must make a choice whether to trade speed in +one part of code for speed in another, or to trade code size for code +speed. In such cases it is useful to know information about how often +some given block will be executed. That is the purpose for maintaining +profile within the flow graph. GCC can handle profile information +obtained through "profile feedback", but it can also estimate branch +probabilities based on statics and heuristics. + + The feedback based profile is produced by compiling the program with +instrumentation, executing it on a train run and reading the numbers of +executions of basic blocks and edges back to the compiler while +re-compiling the program to produce the final executable. This method +provides very accurate information about where a program spends most of +its time on the train run. Whether it matches the average run of +course depends on the choice of train data set, but several studies +have shown that the behavior of a program usually changes just +marginally over different data sets. + + When profile feedback is not available, the compiler may be asked to +attempt to predict the behavior of each branch in the program using a +set of heuristics (see `predict.def' for details) and compute estimated +frequencies of each basic block by propagating the probabilities over +the graph. + + Each `basic_block' contains two integer fields to represent profile +information: `frequency' and `count'. The `frequency' is an estimation +how often is basic block executed within a function. It is represented +as an integer scaled in the range from 0 to `BB_FREQ_BASE'. The most +frequently executed basic block in function is initially set to +`BB_FREQ_BASE' and the rest of frequencies are scaled accordingly. +During optimization, the frequency of the most frequent basic block can +both decrease (for instance by loop unrolling) or grow (for instance by +cross-jumping optimization), so scaling sometimes has to be performed +multiple times. + + The `count' contains hard-counted numbers of execution measured during +training runs and is nonzero only when profile feedback is available. +This value is represented as the host's widest integer (typically a 64 +bit integer) of the special type `gcov_type'. + + Most optimization passes can use only the frequency information of a +basic block, but a few passes may want to know hard execution counts. +The frequencies should always match the counts after scaling, however +during updating of the profile information numerical error may +accumulate into quite large errors. + + Each edge also contains a branch probability field: an integer in the +range from 0 to `REG_BR_PROB_BASE'. It represents probability of +passing control from the end of the `src' basic block to the `dest' +basic block, i.e. the probability that control will flow along this +edge. The `EDGE_FREQUENCY' macro is available to compute how +frequently a given edge is taken. There is a `count' field for each +edge as well, representing same information as for a basic block. + + The basic block frequencies are not represented in the instruction +stream, but in the RTL representation the edge frequencies are +represented for conditional jumps (via the `REG_BR_PROB' macro) since +they are used when instructions are output to the assembly file and the +flow graph is no longer maintained. + + The probability that control flow arrives via a given edge to its +destination basic block is called "reverse probability" and is not +directly represented, but it may be easily computed from frequencies of +basic blocks. + + Updating profile information is a delicate task that can unfortunately +not be easily integrated with the CFG manipulation API. Many of the +functions and hooks to modify the CFG, such as +`redirect_edge_and_branch', do not have enough information to easily +update the profile, so updating it is in the majority of cases left up +to the caller. It is difficult to uncover bugs in the profile updating +code, because they manifest themselves only by producing worse code, +and checking profile consistency is not possible because of numeric +error accumulation. Hence special attention needs to be given to this +issue in each pass that modifies the CFG. + + It is important to point out that `REG_BR_PROB_BASE' and +`BB_FREQ_BASE' are both set low enough to be possible to compute second +power of any frequency or probability in the flow graph, it is not +possible to even square the `count' field, as modern CPUs are fast +enough to execute $2^32$ operations quickly. + + +File: gccint.info, Node: Maintaining the CFG, Next: Liveness information, Prev: Profile information, Up: Control Flow + +15.4 Maintaining the CFG +======================== + +An important task of each compiler pass is to keep both the control +flow graph and all profile information up-to-date. Reconstruction of +the control flow graph after each pass is not an option, since it may be +very expensive and lost profile information cannot be reconstructed at +all. + + GCC has two major intermediate representations, and both use the +`basic_block' and `edge' data types to represent control flow. Both +representations share as much of the CFG maintenance code as possible. +For each representation, a set of "hooks" is defined so that each +representation can provide its own implementation of CFG manipulation +routines when necessary. These hooks are defined in `cfghooks.h'. +There are hooks for almost all common CFG manipulations, including +block splitting and merging, edge redirection and creating and deleting +basic blocks. These hooks should provide everything you need to +maintain and manipulate the CFG in both the RTL and `tree' +representation. + + At the moment, the basic block boundaries are maintained transparently +when modifying instructions, so there rarely is a need to move them +manually (such as in case someone wants to output instruction outside +basic block explicitly). Often the CFG may be better viewed as +integral part of instruction chain, than structure built on the top of +it. However, in principle the control flow graph for the `tree' +representation is _not_ an integral part of the representation, in that +a function tree may be expanded without first building a flow graph +for the `tree' representation at all. This happens when compiling +without any `tree' optimization enabled. When the `tree' optimizations +are enabled and the instruction stream is rewritten in SSA form, the +CFG is very tightly coupled with the instruction stream. In +particular, statement insertion and removal has to be done with care. +In fact, the whole `tree' representation can not be easily used or +maintained without proper maintenance of the CFG simultaneously. + + In the RTL representation, each instruction has a `BLOCK_FOR_INSN' +value that represents pointer to the basic block that contains the +instruction. In the `tree' representation, the function `bb_for_stmt' +returns a pointer to the basic block containing the queried statement. + + When changes need to be applied to a function in its `tree' +representation, "block statement iterators" should be used. These +iterators provide an integrated abstraction of the flow graph and the +instruction stream. Block statement iterators are constructed using +the `block_stmt_iterator' data structure and several modifier are +available, including the following: + +`bsi_start' + This function initializes a `block_stmt_iterator' that points to + the first non-empty statement in a basic block. + +`bsi_last' + This function initializes a `block_stmt_iterator' that points to + the last statement in a basic block. + +`bsi_end_p' + This predicate is `true' if a `block_stmt_iterator' represents the + end of a basic block. + +`bsi_next' + This function takes a `block_stmt_iterator' and makes it point to + its successor. + +`bsi_prev' + This function takes a `block_stmt_iterator' and makes it point to + its predecessor. + +`bsi_insert_after' + This function inserts a statement after the `block_stmt_iterator' + passed in. The final parameter determines whether the statement + iterator is updated to point to the newly inserted statement, or + left pointing to the original statement. + +`bsi_insert_before' + This function inserts a statement before the `block_stmt_iterator' + passed in. The final parameter determines whether the statement + iterator is updated to point to the newly inserted statement, or + left pointing to the original statement. + +`bsi_remove' + This function removes the `block_stmt_iterator' passed in and + rechains the remaining statements in a basic block, if any. + + In the RTL representation, the macros `BB_HEAD' and `BB_END' may be +used to get the head and end `rtx' of a basic block. No abstract +iterators are defined for traversing the insn chain, but you can just +use `NEXT_INSN' and `PREV_INSN' instead. *Note Insns::. + + Usually a code manipulating pass simplifies the instruction stream and +the flow of control, possibly eliminating some edges. This may for +example happen when a conditional jump is replaced with an +unconditional jump, but also when simplifying possibly trapping +instruction to non-trapping while compiling Java. Updating of edges is +not transparent and each optimization pass is required to do so +manually. However only few cases occur in practice. The pass may call +`purge_dead_edges' on a given basic block to remove superfluous edges, +if any. + + Another common scenario is redirection of branch instructions, but +this is best modeled as redirection of edges in the control flow graph +and thus use of `redirect_edge_and_branch' is preferred over more low +level functions, such as `redirect_jump' that operate on RTL chain +only. The CFG hooks defined in `cfghooks.h' should provide the +complete API required for manipulating and maintaining the CFG. + + It is also possible that a pass has to insert control flow instruction +into the middle of a basic block, thus creating an entry point in the +middle of the basic block, which is impossible by definition: The block +must be split to make sure it only has one entry point, i.e. the head +of the basic block. The CFG hook `split_block' may be used when an +instruction in the middle of a basic block has to become the target of +a jump or branch instruction. + + For a global optimizer, a common operation is to split edges in the +flow graph and insert instructions on them. In the RTL representation, +this can be easily done using the `insert_insn_on_edge' function that +emits an instruction "on the edge", caching it for a later +`commit_edge_insertions' call that will take care of moving the +inserted instructions off the edge into the instruction stream +contained in a basic block. This includes the creation of new basic +blocks where needed. In the `tree' representation, the equivalent +functions are `bsi_insert_on_edge' which inserts a block statement +iterator on an edge, and `bsi_commit_edge_inserts' which flushes the +instruction to actual instruction stream. + + While debugging the optimization pass, a `verify_flow_info' function +may be useful to find bugs in the control flow graph updating code. + + Note that at present, the representation of control flow in the `tree' +representation is discarded before expanding to RTL. Long term the CFG +should be maintained and "expanded" to the RTL representation along +with the function `tree' itself. + + +File: gccint.info, Node: Liveness information, Prev: Maintaining the CFG, Up: Control Flow + +15.5 Liveness information +========================= + +Liveness information is useful to determine whether some register is +"live" at given point of program, i.e. that it contains a value that +may be used at a later point in the program. This information is used, +for instance, during register allocation, as the pseudo registers only +need to be assigned to a unique hard register or to a stack slot if +they are live. The hard registers and stack slots may be freely reused +for other values when a register is dead. + + Liveness information is available in the back end starting with +`pass_df_initialize' and ending with `pass_df_finish'. Three flavors +of live analysis are available: With `LR', it is possible to determine +at any point `P' in the function if the register may be used on some +path from `P' to the end of the function. With `UR', it is possible to +determine if there is a path from the beginning of the function to `P' +that defines the variable. `LIVE' is the intersection of the `LR' and +`UR' and a variable is live at `P' if there is both an assignment that +reaches it from the beginning of the function and a use that can be +reached on some path from `P' to the end of the function. + + In general `LIVE' is the most useful of the three. The macros +`DF_[LR,UR,LIVE]_[IN,OUT]' can be used to access this information. The +macros take a basic block number and return a bitmap that is indexed by +the register number. This information is only guaranteed to be up to +date after calls are made to `df_analyze'. See the file `df-core.c' +for details on using the dataflow. + + The liveness information is stored partly in the RTL instruction stream +and partly in the flow graph. Local information is stored in the +instruction stream: Each instruction may contain `REG_DEAD' notes +representing that the value of a given register is no longer needed, or +`REG_UNUSED' notes representing that the value computed by the +instruction is never used. The second is useful for instructions +computing multiple values at once. + + +File: gccint.info, Node: Machine Desc, Next: Target Macros, Prev: Loop Analysis and Representation, Up: Top + +16 Machine Descriptions +*********************** + +A machine description has two parts: a file of instruction patterns +(`.md' file) and a C header file of macro definitions. + + The `.md' file for a target machine contains a pattern for each +instruction that the target machine supports (or at least each +instruction that is worth telling the compiler about). It may also +contain comments. A semicolon causes the rest of the line to be a +comment, unless the semicolon is inside a quoted string. + + See the next chapter for information on the C header file. + +* Menu: + +* Overview:: How the machine description is used. +* Patterns:: How to write instruction patterns. +* Example:: An explained example of a `define_insn' pattern. +* RTL Template:: The RTL template defines what insns match a pattern. +* Output Template:: The output template says how to make assembler code + from such an insn. +* Output Statement:: For more generality, write C code to output + the assembler code. +* Predicates:: Controlling what kinds of operands can be used + for an insn. +* Constraints:: Fine-tuning operand selection. +* Standard Names:: Names mark patterns to use for code generation. +* Pattern Ordering:: When the order of patterns makes a difference. +* Dependent Patterns:: Having one pattern may make you need another. +* Jump Patterns:: Special considerations for patterns for jump insns. +* Looping Patterns:: How to define patterns for special looping insns. +* Insn Canonicalizations::Canonicalization of Instructions +* Expander Definitions::Generating a sequence of several RTL insns + for a standard operation. +* Insn Splitting:: Splitting Instructions into Multiple Instructions. +* Including Patterns:: Including Patterns in Machine Descriptions. +* Peephole Definitions::Defining machine-specific peephole optimizations. +* Insn Attributes:: Specifying the value of attributes for generated insns. +* Conditional Execution::Generating `define_insn' patterns for + predication. +* Constant Definitions::Defining symbolic constants that can be used in the + md file. +* Iterators:: Using iterators to generate patterns from a template. + + +File: gccint.info, Node: Overview, Next: Patterns, Up: Machine Desc + +16.1 Overview of How the Machine Description is Used +==================================================== + +There are three main conversions that happen in the compiler: + + 1. The front end reads the source code and builds a parse tree. + + 2. The parse tree is used to generate an RTL insn list based on named + instruction patterns. + + 3. The insn list is matched against the RTL templates to produce + assembler code. + + + For the generate pass, only the names of the insns matter, from either +a named `define_insn' or a `define_expand'. The compiler will choose +the pattern with the right name and apply the operands according to the +documentation later in this chapter, without regard for the RTL +template or operand constraints. Note that the names the compiler looks +for are hard-coded in the compiler--it will ignore unnamed patterns and +patterns with names it doesn't know about, but if you don't provide a +named pattern it needs, it will abort. + + If a `define_insn' is used, the template given is inserted into the +insn list. If a `define_expand' is used, one of three things happens, +based on the condition logic. The condition logic may manually create +new insns for the insn list, say via `emit_insn()', and invoke `DONE'. +For certain named patterns, it may invoke `FAIL' to tell the compiler +to use an alternate way of performing that task. If it invokes neither +`DONE' nor `FAIL', the template given in the pattern is inserted, as if +the `define_expand' were a `define_insn'. + + Once the insn list is generated, various optimization passes convert, +replace, and rearrange the insns in the insn list. This is where the +`define_split' and `define_peephole' patterns get used, for example. + + Finally, the insn list's RTL is matched up with the RTL templates in +the `define_insn' patterns, and those patterns are used to emit the +final assembly code. For this purpose, each named `define_insn' acts +like it's unnamed, since the names are ignored. + + +File: gccint.info, Node: Patterns, Next: Example, Prev: Overview, Up: Machine Desc + +16.2 Everything about Instruction Patterns +========================================== + +Each instruction pattern contains an incomplete RTL expression, with +pieces to be filled in later, operand constraints that restrict how the +pieces can be filled in, and an output pattern or C code to generate +the assembler output, all wrapped up in a `define_insn' expression. + + A `define_insn' is an RTL expression containing four or five operands: + + 1. An optional name. The presence of a name indicate that this + instruction pattern can perform a certain standard job for the + RTL-generation pass of the compiler. This pass knows certain + names and will use the instruction patterns with those names, if + the names are defined in the machine description. + + The absence of a name is indicated by writing an empty string + where the name should go. Nameless instruction patterns are never + used for generating RTL code, but they may permit several simpler + insns to be combined later on. + + Names that are not thus known and used in RTL-generation have no + effect; they are equivalent to no name at all. + + For the purpose of debugging the compiler, you may also specify a + name beginning with the `*' character. Such a name is used only + for identifying the instruction in RTL dumps; it is entirely + equivalent to having a nameless pattern for all other purposes. + + 2. The "RTL template" (*note RTL Template::) is a vector of incomplete + RTL expressions which show what the instruction should look like. + It is incomplete because it may contain `match_operand', + `match_operator', and `match_dup' expressions that stand for + operands of the instruction. + + If the vector has only one element, that element is the template + for the instruction pattern. If the vector has multiple elements, + then the instruction pattern is a `parallel' expression containing + the elements described. + + 3. A condition. This is a string which contains a C expression that + is the final test to decide whether an insn body matches this + pattern. + + For a named pattern, the condition (if present) may not depend on + the data in the insn being matched, but only the + target-machine-type flags. The compiler needs to test these + conditions during initialization in order to learn exactly which + named instructions are available in a particular run. + + For nameless patterns, the condition is applied only when matching + an individual insn, and only after the insn has matched the + pattern's recognition template. The insn's operands may be found + in the vector `operands'. For an insn where the condition has + once matched, it can't be used to control register allocation, for + example by excluding certain hard registers or hard register + combinations. + + 4. The "output template": a string that says how to output matching + insns as assembler code. `%' in this string specifies where to + substitute the value of an operand. *Note Output Template::. + + When simple substitution isn't general enough, you can specify a + piece of C code to compute the output. *Note Output Statement::. + + 5. Optionally, a vector containing the values of attributes for insns + matching this pattern. *Note Insn Attributes::. + + +File: gccint.info, Node: Example, Next: RTL Template, Prev: Patterns, Up: Machine Desc + +16.3 Example of `define_insn' +============================= + +Here is an actual example of an instruction pattern, for the +68000/68020. + + (define_insn "tstsi" + [(set (cc0) + (match_operand:SI 0 "general_operand" "rm"))] + "" + "* + { + if (TARGET_68020 || ! ADDRESS_REG_P (operands[0])) + return \"tstl %0\"; + return \"cmpl #0,%0\"; + }") + +This can also be written using braced strings: + + (define_insn "tstsi" + [(set (cc0) + (match_operand:SI 0 "general_operand" "rm"))] + "" + { + if (TARGET_68020 || ! ADDRESS_REG_P (operands[0])) + return "tstl %0"; + return "cmpl #0,%0"; + }) + + This is an instruction that sets the condition codes based on the +value of a general operand. It has no condition, so any insn whose RTL +description has the form shown may be handled according to this +pattern. The name `tstsi' means "test a `SImode' value" and tells the +RTL generation pass that, when it is necessary to test such a value, an +insn to do so can be constructed using this pattern. + + The output control string is a piece of C code which chooses which +output template to return based on the kind of operand and the specific +type of CPU for which code is being generated. + + `"rm"' is an operand constraint. Its meaning is explained below. + + +File: gccint.info, Node: RTL Template, Next: Output Template, Prev: Example, Up: Machine Desc + +16.4 RTL Template +================= + +The RTL template is used to define which insns match the particular +pattern and how to find their operands. For named patterns, the RTL +template also says how to construct an insn from specified operands. + + Construction involves substituting specified operands into a copy of +the template. Matching involves determining the values that serve as +the operands in the insn being matched. Both of these activities are +controlled by special expression types that direct matching and +substitution of the operands. + +`(match_operand:M N PREDICATE CONSTRAINT)' + This expression is a placeholder for operand number N of the insn. + When constructing an insn, operand number N will be substituted at + this point. When matching an insn, whatever appears at this + position in the insn will be taken as operand number N; but it + must satisfy PREDICATE or this instruction pattern will not match + at all. + + Operand numbers must be chosen consecutively counting from zero in + each instruction pattern. There may be only one `match_operand' + expression in the pattern for each operand number. Usually + operands are numbered in the order of appearance in `match_operand' + expressions. In the case of a `define_expand', any operand numbers + used only in `match_dup' expressions have higher values than all + other operand numbers. + + PREDICATE is a string that is the name of a function that accepts + two arguments, an expression and a machine mode. *Note + Predicates::. During matching, the function will be called with + the putative operand as the expression and M as the mode argument + (if M is not specified, `VOIDmode' will be used, which normally + causes PREDICATE to accept any mode). If it returns zero, this + instruction pattern fails to match. PREDICATE may be an empty + string; then it means no test is to be done on the operand, so + anything which occurs in this position is valid. + + Most of the time, PREDICATE will reject modes other than M--but + not always. For example, the predicate `address_operand' uses M + as the mode of memory ref that the address should be valid for. + Many predicates accept `const_int' nodes even though their mode is + `VOIDmode'. + + CONSTRAINT controls reloading and the choice of the best register + class to use for a value, as explained later (*note Constraints::). + If the constraint would be an empty string, it can be omitted. + + People are often unclear on the difference between the constraint + and the predicate. The predicate helps decide whether a given + insn matches the pattern. The constraint plays no role in this + decision; instead, it controls various decisions in the case of an + insn which does match. + +`(match_scratch:M N CONSTRAINT)' + This expression is also a placeholder for operand number N and + indicates that operand must be a `scratch' or `reg' expression. + + When matching patterns, this is equivalent to + + (match_operand:M N "scratch_operand" PRED) + + but, when generating RTL, it produces a (`scratch':M) expression. + + If the last few expressions in a `parallel' are `clobber' + expressions whose operands are either a hard register or + `match_scratch', the combiner can add or delete them when + necessary. *Note Side Effects::. + +`(match_dup N)' + This expression is also a placeholder for operand number N. It is + used when the operand needs to appear more than once in the insn. + + In construction, `match_dup' acts just like `match_operand': the + operand is substituted into the insn being constructed. But in + matching, `match_dup' behaves differently. It assumes that operand + number N has already been determined by a `match_operand' + appearing earlier in the recognition template, and it matches only + an identical-looking expression. + + Note that `match_dup' should not be used to tell the compiler that + a particular register is being used for two operands (example: + `add' that adds one register to another; the second register is + both an input operand and the output operand). Use a matching + constraint (*note Simple Constraints::) for those. `match_dup' is + for the cases where one operand is used in two places in the + template, such as an instruction that computes both a quotient and + a remainder, where the opcode takes two input operands but the RTL + template has to refer to each of those twice; once for the + quotient pattern and once for the remainder pattern. + +`(match_operator:M N PREDICATE [OPERANDS...])' + This pattern is a kind of placeholder for a variable RTL expression + code. + + When constructing an insn, it stands for an RTL expression whose + expression code is taken from that of operand N, and whose + operands are constructed from the patterns OPERANDS. + + When matching an expression, it matches an expression if the + function PREDICATE returns nonzero on that expression _and_ the + patterns OPERANDS match the operands of the expression. + + Suppose that the function `commutative_operator' is defined as + follows, to match any expression whose operator is one of the + commutative arithmetic operators of RTL and whose mode is MODE: + + int + commutative_integer_operator (x, mode) + rtx x; + enum machine_mode mode; + { + enum rtx_code code = GET_CODE (x); + if (GET_MODE (x) != mode) + return 0; + return (GET_RTX_CLASS (code) == RTX_COMM_ARITH + || code == EQ || code == NE); + } + + Then the following pattern will match any RTL expression consisting + of a commutative operator applied to two general operands: + + (match_operator:SI 3 "commutative_operator" + [(match_operand:SI 1 "general_operand" "g") + (match_operand:SI 2 "general_operand" "g")]) + + Here the vector `[OPERANDS...]' contains two patterns because the + expressions to be matched all contain two operands. + + When this pattern does match, the two operands of the commutative + operator are recorded as operands 1 and 2 of the insn. (This is + done by the two instances of `match_operand'.) Operand 3 of the + insn will be the entire commutative expression: use `GET_CODE + (operands[3])' to see which commutative operator was used. + + The machine mode M of `match_operator' works like that of + `match_operand': it is passed as the second argument to the + predicate function, and that function is solely responsible for + deciding whether the expression to be matched "has" that mode. + + When constructing an insn, argument 3 of the gen-function will + specify the operation (i.e. the expression code) for the + expression to be made. It should be an RTL expression, whose + expression code is copied into a new expression whose operands are + arguments 1 and 2 of the gen-function. The subexpressions of + argument 3 are not used; only its expression code matters. + + When `match_operator' is used in a pattern for matching an insn, + it usually best if the operand number of the `match_operator' is + higher than that of the actual operands of the insn. This improves + register allocation because the register allocator often looks at + operands 1 and 2 of insns to see if it can do register tying. + + There is no way to specify constraints in `match_operator'. The + operand of the insn which corresponds to the `match_operator' + never has any constraints because it is never reloaded as a whole. + However, if parts of its OPERANDS are matched by `match_operand' + patterns, those parts may have constraints of their own. + +`(match_op_dup:M N[OPERANDS...])' + Like `match_dup', except that it applies to operators instead of + operands. When constructing an insn, operand number N will be + substituted at this point. But in matching, `match_op_dup' behaves + differently. It assumes that operand number N has already been + determined by a `match_operator' appearing earlier in the + recognition template, and it matches only an identical-looking + expression. + +`(match_parallel N PREDICATE [SUBPAT...])' + This pattern is a placeholder for an insn that consists of a + `parallel' expression with a variable number of elements. This + expression should only appear at the top level of an insn pattern. + + When constructing an insn, operand number N will be substituted at + this point. When matching an insn, it matches if the body of the + insn is a `parallel' expression with at least as many elements as + the vector of SUBPAT expressions in the `match_parallel', if each + SUBPAT matches the corresponding element of the `parallel', _and_ + the function PREDICATE returns nonzero on the `parallel' that is + the body of the insn. It is the responsibility of the predicate + to validate elements of the `parallel' beyond those listed in the + `match_parallel'. + + A typical use of `match_parallel' is to match load and store + multiple expressions, which can contain a variable number of + elements in a `parallel'. For example, + + (define_insn "" + [(match_parallel 0 "load_multiple_operation" + [(set (match_operand:SI 1 "gpc_reg_operand" "=r") + (match_operand:SI 2 "memory_operand" "m")) + (use (reg:SI 179)) + (clobber (reg:SI 179))])] + "" + "loadm 0,0,%1,%2") + + This example comes from `a29k.md'. The function + `load_multiple_operation' is defined in `a29k.c' and checks that + subsequent elements in the `parallel' are the same as the `set' in + the pattern, except that they are referencing subsequent registers + and memory locations. + + An insn that matches this pattern might look like: + + (parallel + [(set (reg:SI 20) (mem:SI (reg:SI 100))) + (use (reg:SI 179)) + (clobber (reg:SI 179)) + (set (reg:SI 21) + (mem:SI (plus:SI (reg:SI 100) + (const_int 4)))) + (set (reg:SI 22) + (mem:SI (plus:SI (reg:SI 100) + (const_int 8))))]) + +`(match_par_dup N [SUBPAT...])' + Like `match_op_dup', but for `match_parallel' instead of + `match_operator'. + + + +File: gccint.info, Node: Output Template, Next: Output Statement, Prev: RTL Template, Up: Machine Desc + +16.5 Output Templates and Operand Substitution +============================================== + +The "output template" is a string which specifies how to output the +assembler code for an instruction pattern. Most of the template is a +fixed string which is output literally. The character `%' is used to +specify where to substitute an operand; it can also be used to identify +places where different variants of the assembler require different +syntax. + + In the simplest case, a `%' followed by a digit N says to output +operand N at that point in the string. + + `%' followed by a letter and a digit says to output an operand in an +alternate fashion. Four letters have standard, built-in meanings +described below. The machine description macro `PRINT_OPERAND' can +define additional letters with nonstandard meanings. + + `%cDIGIT' can be used to substitute an operand that is a constant +value without the syntax that normally indicates an immediate operand. + + `%nDIGIT' is like `%cDIGIT' except that the value of the constant is +negated before printing. + + `%aDIGIT' can be used to substitute an operand as if it were a memory +reference, with the actual operand treated as the address. This may be +useful when outputting a "load address" instruction, because often the +assembler syntax for such an instruction requires you to write the +operand as if it were a memory reference. + + `%lDIGIT' is used to substitute a `label_ref' into a jump instruction. + + `%=' outputs a number which is unique to each instruction in the +entire compilation. This is useful for making local labels to be +referred to more than once in a single template that generates multiple +assembler instructions. + + `%' followed by a punctuation character specifies a substitution that +does not use an operand. Only one case is standard: `%%' outputs a `%' +into the assembler code. Other nonstandard cases can be defined in the +`PRINT_OPERAND' macro. You must also define which punctuation +characters are valid with the `PRINT_OPERAND_PUNCT_VALID_P' macro. + + The template may generate multiple assembler instructions. Write the +text for the instructions, with `\;' between them. + + When the RTL contains two operands which are required by constraint to +match each other, the output template must refer only to the +lower-numbered operand. Matching operands are not always identical, +and the rest of the compiler arranges to put the proper RTL expression +for printing into the lower-numbered operand. + + One use of nonstandard letters or punctuation following `%' is to +distinguish between different assembler languages for the same machine; +for example, Motorola syntax versus MIT syntax for the 68000. Motorola +syntax requires periods in most opcode names, while MIT syntax does +not. For example, the opcode `movel' in MIT syntax is `move.l' in +Motorola syntax. The same file of patterns is used for both kinds of +output syntax, but the character sequence `%.' is used in each place +where Motorola syntax wants a period. The `PRINT_OPERAND' macro for +Motorola syntax defines the sequence to output a period; the macro for +MIT syntax defines it to do nothing. + + As a special case, a template consisting of the single character `#' +instructs the compiler to first split the insn, and then output the +resulting instructions separately. This helps eliminate redundancy in +the output templates. If you have a `define_insn' that needs to emit +multiple assembler instructions, and there is a matching `define_split' +already defined, then you can simply use `#' as the output template +instead of writing an output template that emits the multiple assembler +instructions. + + If the macro `ASSEMBLER_DIALECT' is defined, you can use construct of +the form `{option0|option1|option2}' in the templates. These describe +multiple variants of assembler language syntax. *Note Instruction +Output::. + + +File: gccint.info, Node: Output Statement, Next: Predicates, Prev: Output Template, Up: Machine Desc + +16.6 C Statements for Assembler Output +====================================== + +Often a single fixed template string cannot produce correct and +efficient assembler code for all the cases that are recognized by a +single instruction pattern. For example, the opcodes may depend on the +kinds of operands; or some unfortunate combinations of operands may +require extra machine instructions. + + If the output control string starts with a `@', then it is actually a +series of templates, each on a separate line. (Blank lines and leading +spaces and tabs are ignored.) The templates correspond to the +pattern's constraint alternatives (*note Multi-Alternative::). For +example, if a target machine has a two-address add instruction `addr' +to add into a register and another `addm' to add a register to memory, +you might write this pattern: + + (define_insn "addsi3" + [(set (match_operand:SI 0 "general_operand" "=r,m") + (plus:SI (match_operand:SI 1 "general_operand" "0,0") + (match_operand:SI 2 "general_operand" "g,r")))] + "" + "@ + addr %2,%0 + addm %2,%0") + + If the output control string starts with a `*', then it is not an +output template but rather a piece of C program that should compute a +template. It should execute a `return' statement to return the +template-string you want. Most such templates use C string literals, +which require doublequote characters to delimit them. To include these +doublequote characters in the string, prefix each one with `\'. + + If the output control string is written as a brace block instead of a +double-quoted string, it is automatically assumed to be C code. In that +case, it is not necessary to put in a leading asterisk, or to escape the +doublequotes surrounding C string literals. + + The operands may be found in the array `operands', whose C data type +is `rtx []'. + + It is very common to select different ways of generating assembler code +based on whether an immediate operand is within a certain range. Be +careful when doing this, because the result of `INTVAL' is an integer +on the host machine. If the host machine has more bits in an `int' +than the target machine has in the mode in which the constant will be +used, then some of the bits you get from `INTVAL' will be superfluous. +For proper results, you must carefully disregard the values of those +bits. + + It is possible to output an assembler instruction and then go on to +output or compute more of them, using the subroutine `output_asm_insn'. +This receives two arguments: a template-string and a vector of +operands. The vector may be `operands', or it may be another array of +`rtx' that you declare locally and initialize yourself. + + When an insn pattern has multiple alternatives in its constraints, +often the appearance of the assembler code is determined mostly by +which alternative was matched. When this is so, the C code can test +the variable `which_alternative', which is the ordinal number of the +alternative that was actually satisfied (0 for the first, 1 for the +second alternative, etc.). + + For example, suppose there are two opcodes for storing zero, `clrreg' +for registers and `clrmem' for memory locations. Here is how a pattern +could use `which_alternative' to choose between them: + + (define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r,m") + (const_int 0))] + "" + { + return (which_alternative == 0 + ? "clrreg %0" : "clrmem %0"); + }) + + The example above, where the assembler code to generate was _solely_ +determined by the alternative, could also have been specified as +follows, having the output control string start with a `@': + + (define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r,m") + (const_int 0))] + "" + "@ + clrreg %0 + clrmem %0") + + +File: gccint.info, Node: Predicates, Next: Constraints, Prev: Output Statement, Up: Machine Desc + +16.7 Predicates +=============== + +A predicate determines whether a `match_operand' or `match_operator' +expression matches, and therefore whether the surrounding instruction +pattern will be used for that combination of operands. GCC has a +number of machine-independent predicates, and you can define +machine-specific predicates as needed. By convention, predicates used +with `match_operand' have names that end in `_operand', and those used +with `match_operator' have names that end in `_operator'. + + All predicates are Boolean functions (in the mathematical sense) of +two arguments: the RTL expression that is being considered at that +position in the instruction pattern, and the machine mode that the +`match_operand' or `match_operator' specifies. In this section, the +first argument is called OP and the second argument MODE. Predicates +can be called from C as ordinary two-argument functions; this can be +useful in output templates or other machine-specific code. + + Operand predicates can allow operands that are not actually acceptable +to the hardware, as long as the constraints give reload the ability to +fix them up (*note Constraints::). However, GCC will usually generate +better code if the predicates specify the requirements of the machine +instructions as closely as possible. Reload cannot fix up operands +that must be constants ("immediate operands"); you must use a predicate +that allows only constants, or else enforce the requirement in the +extra condition. + + Most predicates handle their MODE argument in a uniform manner. If +MODE is `VOIDmode' (unspecified), then OP can have any mode. If MODE +is anything else, then OP must have the same mode, unless OP is a +`CONST_INT' or integer `CONST_DOUBLE'. These RTL expressions always +have `VOIDmode', so it would be counterproductive to check that their +mode matches. Instead, predicates that accept `CONST_INT' and/or +integer `CONST_DOUBLE' check that the value stored in the constant will +fit in the requested mode. + + Predicates with this behavior are called "normal". `genrecog' can +optimize the instruction recognizer based on knowledge of how normal +predicates treat modes. It can also diagnose certain kinds of common +errors in the use of normal predicates; for instance, it is almost +always an error to use a normal predicate without specifying a mode. + + Predicates that do something different with their MODE argument are +called "special". The generic predicates `address_operand' and +`pmode_register_operand' are special predicates. `genrecog' does not +do any optimizations or diagnosis when special predicates are used. + +* Menu: + +* Machine-Independent Predicates:: Predicates available to all back ends. +* Defining Predicates:: How to write machine-specific predicate + functions. + + +File: gccint.info, Node: Machine-Independent Predicates, Next: Defining Predicates, Up: Predicates + +16.7.1 Machine-Independent Predicates +------------------------------------- + +These are the generic predicates available to all back ends. They are +defined in `recog.c'. The first category of predicates allow only +constant, or "immediate", operands. + + -- Function: immediate_operand + This predicate allows any sort of constant that fits in MODE. It + is an appropriate choice for instructions that take operands that + must be constant. + + -- Function: const_int_operand + This predicate allows any `CONST_INT' expression that fits in + MODE. It is an appropriate choice for an immediate operand that + does not allow a symbol or label. + + -- Function: const_double_operand + This predicate accepts any `CONST_DOUBLE' expression that has + exactly MODE. If MODE is `VOIDmode', it will also accept + `CONST_INT'. It is intended for immediate floating point + constants. + +The second category of predicates allow only some kind of machine +register. + + -- Function: register_operand + This predicate allows any `REG' or `SUBREG' expression that is + valid for MODE. It is often suitable for arithmetic instruction + operands on a RISC machine. + + -- Function: pmode_register_operand + This is a slight variant on `register_operand' which works around + a limitation in the machine-description reader. + + (match_operand N "pmode_register_operand" CONSTRAINT) + + means exactly what + + (match_operand:P N "register_operand" CONSTRAINT) + + would mean, if the machine-description reader accepted `:P' mode + suffixes. Unfortunately, it cannot, because `Pmode' is an alias + for some other mode, and might vary with machine-specific options. + *Note Misc::. + + -- Function: scratch_operand + This predicate allows hard registers and `SCRATCH' expressions, + but not pseudo-registers. It is used internally by + `match_scratch'; it should not be used directly. + +The third category of predicates allow only some kind of memory +reference. + + -- Function: memory_operand + This predicate allows any valid reference to a quantity of mode + MODE in memory, as determined by the weak form of + `GO_IF_LEGITIMATE_ADDRESS' (*note Addressing Modes::). + + -- Function: address_operand + This predicate is a little unusual; it allows any operand that is a + valid expression for the _address_ of a quantity of mode MODE, + again determined by the weak form of `GO_IF_LEGITIMATE_ADDRESS'. + To first order, if `(mem:MODE (EXP))' is acceptable to + `memory_operand', then EXP is acceptable to `address_operand'. + Note that EXP does not necessarily have the mode MODE. + + -- Function: indirect_operand + This is a stricter form of `memory_operand' which allows only + memory references with a `general_operand' as the address + expression. New uses of this predicate are discouraged, because + `general_operand' is very permissive, so it's hard to tell what an + `indirect_operand' does or does not allow. If a target has + different requirements for memory operands for different + instructions, it is better to define target-specific predicates + which enforce the hardware's requirements explicitly. + + -- Function: push_operand + This predicate allows a memory reference suitable for pushing a + value onto the stack. This will be a `MEM' which refers to + `stack_pointer_rtx', with a side-effect in its address expression + (*note Incdec::); which one is determined by the `STACK_PUSH_CODE' + macro (*note Frame Layout::). + + -- Function: pop_operand + This predicate allows a memory reference suitable for popping a + value off the stack. Again, this will be a `MEM' referring to + `stack_pointer_rtx', with a side-effect in its address expression. + However, this time `STACK_POP_CODE' is expected. + +The fourth category of predicates allow some combination of the above +operands. + + -- Function: nonmemory_operand + This predicate allows any immediate or register operand valid for + MODE. + + -- Function: nonimmediate_operand + This predicate allows any register or memory operand valid for + MODE. + + -- Function: general_operand + This predicate allows any immediate, register, or memory operand + valid for MODE. + +Finally, there are two generic operator predicates. + + -- Function: comparison_operator + This predicate matches any expression which performs an arithmetic + comparison in MODE; that is, `COMPARISON_P' is true for the + expression code. + + -- Function: ordered_comparison_operator + This predicate matches any expression which performs an arithmetic + comparison in MODE and whose expression code is valid for integer + modes; that is, the expression code will be one of `eq', `ne', + `lt', `ltu', `le', `leu', `gt', `gtu', `ge', `geu'. + + +File: gccint.info, Node: Defining Predicates, Prev: Machine-Independent Predicates, Up: Predicates + +16.7.2 Defining Machine-Specific Predicates +------------------------------------------- + +Many machines have requirements for their operands that cannot be +expressed precisely using the generic predicates. You can define +additional predicates using `define_predicate' and +`define_special_predicate' expressions. These expressions have three +operands: + + * The name of the predicate, as it will be referred to in + `match_operand' or `match_operator' expressions. + + * An RTL expression which evaluates to true if the predicate allows + the operand OP, false if it does not. This expression can only use + the following RTL codes: + + `MATCH_OPERAND' + When written inside a predicate expression, a `MATCH_OPERAND' + expression evaluates to true if the predicate it names would + allow OP. The operand number and constraint are ignored. + Due to limitations in `genrecog', you can only refer to + generic predicates and predicates that have already been + defined. + + `MATCH_CODE' + This expression evaluates to true if OP or a specified + subexpression of OP has one of a given list of RTX codes. + + The first operand of this expression is a string constant + containing a comma-separated list of RTX code names (in lower + case). These are the codes for which the `MATCH_CODE' will + be true. + + The second operand is a string constant which indicates what + subexpression of OP to examine. If it is absent or the empty + string, OP itself is examined. Otherwise, the string constant + must be a sequence of digits and/or lowercase letters. Each + character indicates a subexpression to extract from the + current expression; for the first character this is OP, for + the second and subsequent characters it is the result of the + previous character. A digit N extracts `XEXP (E, N)'; a + letter L extracts `XVECEXP (E, 0, N)' where N is the + alphabetic ordinal of L (0 for `a', 1 for 'b', and so on). + The `MATCH_CODE' then examines the RTX code of the + subexpression extracted by the complete string. It is not + possible to extract components of an `rtvec' that is not at + position 0 within its RTX object. + + `MATCH_TEST' + This expression has one operand, a string constant containing + a C expression. The predicate's arguments, OP and MODE, are + available with those names in the C expression. The + `MATCH_TEST' evaluates to true if the C expression evaluates + to a nonzero value. `MATCH_TEST' expressions must not have + side effects. + + `AND' + `IOR' + `NOT' + `IF_THEN_ELSE' + The basic `MATCH_' expressions can be combined using these + logical operators, which have the semantics of the C operators + `&&', `||', `!', and `? :' respectively. As in Common Lisp, + you may give an `AND' or `IOR' expression an arbitrary number + of arguments; this has exactly the same effect as writing a + chain of two-argument `AND' or `IOR' expressions. + + * An optional block of C code, which should execute `return true' if + the predicate is found to match and `return false' if it does not. + It must not have any side effects. The predicate arguments, OP + and MODE, are available with those names. + + If a code block is present in a predicate definition, then the RTL + expression must evaluate to true _and_ the code block must execute + `return true' for the predicate to allow the operand. The RTL + expression is evaluated first; do not re-check anything in the + code block that was checked in the RTL expression. + + The program `genrecog' scans `define_predicate' and +`define_special_predicate' expressions to determine which RTX codes are +possibly allowed. You should always make this explicit in the RTL +predicate expression, using `MATCH_OPERAND' and `MATCH_CODE'. + + Here is an example of a simple predicate definition, from the IA64 +machine description: + + ;; True if OP is a `SYMBOL_REF' which refers to the sdata section. + (define_predicate "small_addr_symbolic_operand" + (and (match_code "symbol_ref") + (match_test "SYMBOL_REF_SMALL_ADDR_P (op)"))) + +And here is another, showing the use of the C block. + + ;; True if OP is a register operand that is (or could be) a GR reg. + (define_predicate "gr_register_operand" + (match_operand 0 "register_operand") + { + unsigned int regno; + if (GET_CODE (op) == SUBREG) + op = SUBREG_REG (op); + + regno = REGNO (op); + return (regno >= FIRST_PSEUDO_REGISTER || GENERAL_REGNO_P (regno)); + }) + + Predicates written with `define_predicate' automatically include a +test that MODE is `VOIDmode', or OP has the same mode as MODE, or OP is +a `CONST_INT' or `CONST_DOUBLE'. They do _not_ check specifically for +integer `CONST_DOUBLE', nor do they test that the value of either kind +of constant fits in the requested mode. This is because +target-specific predicates that take constants usually have to do more +stringent value checks anyway. If you need the exact same treatment of +`CONST_INT' or `CONST_DOUBLE' that the generic predicates provide, use +a `MATCH_OPERAND' subexpression to call `const_int_operand', +`const_double_operand', or `immediate_operand'. + + Predicates written with `define_special_predicate' do not get any +automatic mode checks, and are treated as having special mode handling +by `genrecog'. + + The program `genpreds' is responsible for generating code to test +predicates. It also writes a header file containing function +declarations for all machine-specific predicates. It is not necessary +to declare these predicates in `CPU-protos.h'. + + +File: gccint.info, Node: Constraints, Next: Standard Names, Prev: Predicates, Up: Machine Desc + +16.8 Operand Constraints +======================== + +Each `match_operand' in an instruction pattern can specify constraints +for the operands allowed. The constraints allow you to fine-tune +matching within the set of operands allowed by the predicate. + + Constraints can say whether an operand may be in a register, and which +kinds of register; whether the operand can be a memory reference, and +which kinds of address; whether the operand may be an immediate +constant, and which possible values it may have. Constraints can also +require two operands to match. Side-effects aren't allowed in operands +of inline `asm', unless `<' or `>' constraints are used, because there +is no guarantee that the side-effects will happen exactly once in an +instruction that can update the addressing register. + +* Menu: + +* Simple Constraints:: Basic use of constraints. +* Multi-Alternative:: When an insn has two alternative constraint-patterns. +* Class Preferences:: Constraints guide which hard register to put things in. +* Modifiers:: More precise control over effects of constraints. +* Disable Insn Alternatives:: Disable insn alternatives using the `enabled' attribute. +* Machine Constraints:: Existing constraints for some particular machines. +* Define Constraints:: How to define machine-specific constraints. +* C Constraint Interface:: How to test constraints from C code. + + +File: gccint.info, Node: Simple Constraints, Next: Multi-Alternative, Up: Constraints + +16.8.1 Simple Constraints +------------------------- + +The simplest kind of constraint is a string full of letters, each of +which describes one kind of operand that is permitted. Here are the +letters that are allowed: + +whitespace + Whitespace characters are ignored and can be inserted at any + position except the first. This enables each alternative for + different operands to be visually aligned in the machine + description even if they have different number of constraints and + modifiers. + +`m' + A memory operand is allowed, with any kind of address that the + machine supports in general. Note that the letter used for the + general memory constraint can be re-defined by a back end using + the `TARGET_MEM_CONSTRAINT' macro. + +`o' + A memory operand is allowed, but only if the address is + "offsettable". This means that adding a small integer (actually, + the width in bytes of the operand, as determined by its machine + mode) may be added to the address and the result is also a valid + memory address. + + For example, an address which is constant is offsettable; so is an + address that is the sum of a register and a constant (as long as a + slightly larger constant is also within the range of + address-offsets supported by the machine); but an autoincrement or + autodecrement address is not offsettable. More complicated + indirect/indexed addresses may or may not be offsettable depending + on the other addressing modes that the machine supports. + + Note that in an output operand which can be matched by another + operand, the constraint letter `o' is valid only when accompanied + by both `<' (if the target machine has predecrement addressing) + and `>' (if the target machine has preincrement addressing). + +`V' + A memory operand that is not offsettable. In other words, + anything that would fit the `m' constraint but not the `o' + constraint. + +`<' + A memory operand with autodecrement addressing (either + predecrement or postdecrement) is allowed. In inline `asm' this + constraint is only allowed if the operand is used exactly once in + an instruction that can handle the side-effects. Not using an + operand with `<' in constraint string in the inline `asm' pattern + at all or using it in multiple instructions isn't valid, because + the side-effects wouldn't be performed or would be performed more + than once. Furthermore, on some targets the operand with `<' in + constraint string must be accompanied by special instruction + suffixes like `%U0' instruction suffix on PowerPC or `%P0' on + IA-64. + +`>' + A memory operand with autoincrement addressing (either + preincrement or postincrement) is allowed. In inline `asm' the + same restrictions as for `<' apply. + +`r' + A register operand is allowed provided that it is in a general + register. + +`i' + An immediate integer operand (one with constant value) is allowed. + This includes symbolic constants whose values will be known only at + assembly time or later. + +`n' + An immediate integer operand with a known numeric value is allowed. + Many systems cannot support assembly-time constants for operands + less than a word wide. Constraints for these operands should use + `n' rather than `i'. + +`I', `J', `K', ... `P' + Other letters in the range `I' through `P' may be defined in a + machine-dependent fashion to permit immediate integer operands with + explicit integer values in specified ranges. For example, on the + 68000, `I' is defined to stand for the range of values 1 to 8. + This is the range permitted as a shift count in the shift + instructions. + +`E' + An immediate floating operand (expression code `const_double') is + allowed, but only if the target floating point format is the same + as that of the host machine (on which the compiler is running). + +`F' + An immediate floating operand (expression code `const_double' or + `const_vector') is allowed. + +`G', `H' + `G' and `H' may be defined in a machine-dependent fashion to + permit immediate floating operands in particular ranges of values. + +`s' + An immediate integer operand whose value is not an explicit + integer is allowed. + + This might appear strange; if an insn allows a constant operand + with a value not known at compile time, it certainly must allow + any known value. So why use `s' instead of `i'? Sometimes it + allows better code to be generated. + + For example, on the 68000 in a fullword instruction it is possible + to use an immediate operand; but if the immediate value is between + -128 and 127, better code results from loading the value into a + register and using the register. This is because the load into + the register can be done with a `moveq' instruction. We arrange + for this to happen by defining the letter `K' to mean "any integer + outside the range -128 to 127", and then specifying `Ks' in the + operand constraints. + +`g' + Any register, memory or immediate integer operand is allowed, + except for registers that are not general registers. + +`X' + Any operand whatsoever is allowed, even if it does not satisfy + `general_operand'. This is normally used in the constraint of a + `match_scratch' when certain alternatives will not actually + require a scratch register. + +`0', `1', `2', ... `9' + An operand that matches the specified operand number is allowed. + If a digit is used together with letters within the same + alternative, the digit should come last. + + This number is allowed to be more than a single digit. If multiple + digits are encountered consecutively, they are interpreted as a + single decimal integer. There is scant chance for ambiguity, + since to-date it has never been desirable that `10' be interpreted + as matching either operand 1 _or_ operand 0. Should this be + desired, one can use multiple alternatives instead. + + This is called a "matching constraint" and what it really means is + that the assembler has only a single operand that fills two roles + considered separate in the RTL insn. For example, an add insn has + two input operands and one output operand in the RTL, but on most + CISC machines an add instruction really has only two operands, one + of them an input-output operand: + + addl #35,r12 + + Matching constraints are used in these circumstances. More + precisely, the two operands that match must include one input-only + operand and one output-only operand. Moreover, the digit must be a + smaller number than the number of the operand that uses it in the + constraint. + + For operands to match in a particular case usually means that they + are identical-looking RTL expressions. But in a few special cases + specific kinds of dissimilarity are allowed. For example, `*x' as + an input operand will match `*x++' as an output operand. For + proper results in such cases, the output template should always + use the output-operand's number when printing the operand. + +`p' + An operand that is a valid memory address is allowed. This is for + "load address" and "push address" instructions. + + `p' in the constraint must be accompanied by `address_operand' as + the predicate in the `match_operand'. This predicate interprets + the mode specified in the `match_operand' as the mode of the memory + reference for which the address would be valid. + +OTHER-LETTERS + Other letters can be defined in machine-dependent fashion to stand + for particular classes of registers or other arbitrary operand + types. `d', `a' and `f' are defined on the 68000/68020 to stand + for data, address and floating point registers. + + In order to have valid assembler code, each operand must satisfy its +constraint. But a failure to do so does not prevent the pattern from +applying to an insn. Instead, it directs the compiler to modify the +code so that the constraint will be satisfied. Usually this is done by +copying an operand into a register. + + Contrast, therefore, the two instruction patterns that follow: + + (define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r") + (plus:SI (match_dup 0) + (match_operand:SI 1 "general_operand" "r")))] + "" + "...") + +which has two operands, one of which must appear in two places, and + + (define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r") + (plus:SI (match_operand:SI 1 "general_operand" "0") + (match_operand:SI 2 "general_operand" "r")))] + "" + "...") + +which has three operands, two of which are required by a constraint to +be identical. If we are considering an insn of the form + + (insn N PREV NEXT + (set (reg:SI 3) + (plus:SI (reg:SI 6) (reg:SI 109))) + ...) + +the first pattern would not apply at all, because this insn does not +contain two identical subexpressions in the right place. The pattern +would say, "That does not look like an add instruction; try other +patterns". The second pattern would say, "Yes, that's an add +instruction, but there is something wrong with it". It would direct +the reload pass of the compiler to generate additional insns to make +the constraint true. The results might look like this: + + (insn N2 PREV N + (set (reg:SI 3) (reg:SI 6)) + ...) + + (insn N N2 NEXT + (set (reg:SI 3) + (plus:SI (reg:SI 3) (reg:SI 109))) + ...) + + It is up to you to make sure that each operand, in each pattern, has +constraints that can handle any RTL expression that could be present for +that operand. (When multiple alternatives are in use, each pattern +must, for each possible combination of operand expressions, have at +least one alternative which can handle that combination of operands.) +The constraints don't need to _allow_ any possible operand--when this is +the case, they do not constrain--but they must at least point the way to +reloading any possible operand so that it will fit. + + * If the constraint accepts whatever operands the predicate permits, + there is no problem: reloading is never necessary for this operand. + + For example, an operand whose constraints permit everything except + registers is safe provided its predicate rejects registers. + + An operand whose predicate accepts only constant values is safe + provided its constraints include the letter `i'. If any possible + constant value is accepted, then nothing less than `i' will do; if + the predicate is more selective, then the constraints may also be + more selective. + + * Any operand expression can be reloaded by copying it into a + register. So if an operand's constraints allow some kind of + register, it is certain to be safe. It need not permit all + classes of registers; the compiler knows how to copy a register + into another register of the proper class in order to make an + instruction valid. + + * A nonoffsettable memory reference can be reloaded by copying the + address into a register. So if the constraint uses the letter + `o', all memory references are taken care of. + + * A constant operand can be reloaded by allocating space in memory to + hold it as preinitialized data. Then the memory reference can be + used in place of the constant. So if the constraint uses the + letters `o' or `m', constant operands are not a problem. + + * If the constraint permits a constant and a pseudo register used in + an insn was not allocated to a hard register and is equivalent to + a constant, the register will be replaced with the constant. If + the predicate does not permit a constant and the insn is + re-recognized for some reason, the compiler will crash. Thus the + predicate must always recognize any objects allowed by the + constraint. + + If the operand's predicate can recognize registers, but the constraint +does not permit them, it can make the compiler crash. When this +operand happens to be a register, the reload pass will be stymied, +because it does not know how to copy a register temporarily into memory. + + If the predicate accepts a unary operator, the constraint applies to +the operand. For example, the MIPS processor at ISA level 3 supports an +instruction which adds two registers in `SImode' to produce a `DImode' +result, but only if the registers are correctly sign extended. This +predicate for the input operands accepts a `sign_extend' of an `SImode' +register. Write the constraint to indicate the type of register that +is required for the operand of the `sign_extend'. + + +File: gccint.info, Node: Multi-Alternative, Next: Class Preferences, Prev: Simple Constraints, Up: Constraints + +16.8.2 Multiple Alternative Constraints +--------------------------------------- + +Sometimes a single instruction has multiple alternative sets of possible +operands. For example, on the 68000, a logical-or instruction can +combine register or an immediate value into memory, or it can combine +any kind of operand into a register; but it cannot combine one memory +location into another. + + These constraints are represented as multiple alternatives. An +alternative can be described by a series of letters for each operand. +The overall constraint for an operand is made from the letters for this +operand from the first alternative, a comma, the letters for this +operand from the second alternative, a comma, and so on until the last +alternative. Here is how it is done for fullword logical-or on the +68000: + + (define_insn "iorsi3" + [(set (match_operand:SI 0 "general_operand" "=m,d") + (ior:SI (match_operand:SI 1 "general_operand" "%0,0") + (match_operand:SI 2 "general_operand" "dKs,dmKs")))] + ...) + + The first alternative has `m' (memory) for operand 0, `0' for operand +1 (meaning it must match operand 0), and `dKs' for operand 2. The +second alternative has `d' (data register) for operand 0, `0' for +operand 1, and `dmKs' for operand 2. The `=' and `%' in the +constraints apply to all the alternatives; their meaning is explained +in the next section (*note Class Preferences::). + + If all the operands fit any one alternative, the instruction is valid. +Otherwise, for each alternative, the compiler counts how many +instructions must be added to copy the operands so that that +alternative applies. The alternative requiring the least copying is +chosen. If two alternatives need the same amount of copying, the one +that comes first is chosen. These choices can be altered with the `?' +and `!' characters: + +`?' + Disparage slightly the alternative that the `?' appears in, as a + choice when no alternative applies exactly. The compiler regards + this alternative as one unit more costly for each `?' that appears + in it. + +`!' + Disparage severely the alternative that the `!' appears in. This + alternative can still be used if it fits without reloading, but if + reloading is needed, some other alternative will be used. + + When an insn pattern has multiple alternatives in its constraints, +often the appearance of the assembler code is determined mostly by which +alternative was matched. When this is so, the C code for writing the +assembler code can use the variable `which_alternative', which is the +ordinal number of the alternative that was actually satisfied (0 for +the first, 1 for the second alternative, etc.). *Note Output +Statement::. + + +File: gccint.info, Node: Class Preferences, Next: Modifiers, Prev: Multi-Alternative, Up: Constraints + +16.8.3 Register Class Preferences +--------------------------------- + +The operand constraints have another function: they enable the compiler +to decide which kind of hardware register a pseudo register is best +allocated to. The compiler examines the constraints that apply to the +insns that use the pseudo register, looking for the machine-dependent +letters such as `d' and `a' that specify classes of registers. The +pseudo register is put in whichever class gets the most "votes". The +constraint letters `g' and `r' also vote: they vote in favor of a +general register. The machine description says which registers are +considered general. + + Of course, on some machines all registers are equivalent, and no +register classes are defined. Then none of this complexity is relevant. + + +File: gccint.info, Node: Modifiers, Next: Disable Insn Alternatives, Prev: Class Preferences, Up: Constraints + +16.8.4 Constraint Modifier Characters +------------------------------------- + +Here are constraint modifier characters. + +`=' + Means that this operand is write-only for this instruction: the + previous value is discarded and replaced by output data. + +`+' + Means that this operand is both read and written by the + instruction. + + When the compiler fixes up the operands to satisfy the constraints, + it needs to know which operands are inputs to the instruction and + which are outputs from it. `=' identifies an output; `+' + identifies an operand that is both input and output; all other + operands are assumed to be input only. + + If you specify `=' or `+' in a constraint, you put it in the first + character of the constraint string. + +`&' + Means (in a particular alternative) that this operand is an + "earlyclobber" operand, which is modified before the instruction is + finished using the input operands. Therefore, this operand may + not lie in a register that is used as an input operand or as part + of any memory address. + + `&' applies only to the alternative in which it is written. In + constraints with multiple alternatives, sometimes one alternative + requires `&' while others do not. See, for example, the `movdf' + insn of the 68000. + + An input operand can be tied to an earlyclobber operand if its only + use as an input occurs before the early result is written. Adding + alternatives of this form often allows GCC to produce better code + when only some of the inputs can be affected by the earlyclobber. + See, for example, the `mulsi3' insn of the ARM. + + `&' does not obviate the need to write `='. + +`%' + Declares the instruction to be commutative for this operand and the + following operand. This means that the compiler may interchange + the two operands if that is the cheapest way to make all operands + fit the constraints. This is often used in patterns for addition + instructions that really have only two operands: the result must + go in one of the arguments. Here for example, is how the 68000 + halfword-add instruction is defined: + + (define_insn "addhi3" + [(set (match_operand:HI 0 "general_operand" "=m,r") + (plus:HI (match_operand:HI 1 "general_operand" "%0,0") + (match_operand:HI 2 "general_operand" "di,g")))] + ...) + GCC can only handle one commutative pair in an asm; if you use + more, the compiler may fail. Note that you need not use the + modifier if the two alternatives are strictly identical; this + would only waste time in the reload pass. The modifier is not + operational after register allocation, so the result of + `define_peephole2' and `define_split's performed after reload + cannot rely on `%' to make the intended insn match. + +`#' + Says that all following characters, up to the next comma, are to be + ignored as a constraint. They are significant only for choosing + register preferences. + +`*' + Says that the following character should be ignored when choosing + register preferences. `*' has no effect on the meaning of the + constraint as a constraint, and no effect on reloading. + + Here is an example: the 68000 has an instruction to sign-extend a + halfword in a data register, and can also sign-extend a value by + copying it into an address register. While either kind of + register is acceptable, the constraints on an address-register + destination are less strict, so it is best if register allocation + makes an address register its goal. Therefore, `*' is used so + that the `d' constraint letter (for data register) is ignored when + computing register preferences. + + (define_insn "extendhisi2" + [(set (match_operand:SI 0 "general_operand" "=*d,a") + (sign_extend:SI + (match_operand:HI 1 "general_operand" "0,g")))] + ...) + + +File: gccint.info, Node: Machine Constraints, Next: Define Constraints, Prev: Disable Insn Alternatives, Up: Constraints + +16.8.5 Constraints for Particular Machines +------------------------------------------ + +Whenever possible, you should use the general-purpose constraint letters +in `asm' arguments, since they will convey meaning more readily to +people reading your code. Failing that, use the constraint letters +that usually have very similar meanings across architectures. The most +commonly used constraints are `m' and `r' (for memory and +general-purpose registers respectively; *note Simple Constraints::), and +`I', usually the letter indicating the most common immediate-constant +format. + + Each architecture defines additional constraints. These constraints +are used by the compiler itself for instruction generation, as well as +for `asm' statements; therefore, some of the constraints are not +particularly useful for `asm'. Here is a summary of some of the +machine-dependent constraints available on some particular machines; it +includes both constraints that are useful for `asm' and constraints +that aren't. The compiler source file mentioned in the table heading +for each architecture is the definitive reference for the meanings of +that architecture's constraints. + +_ARM family--`config/arm/arm.h'_ + + `f' + Floating-point register + + `w' + VFP floating-point register + + `F' + One of the floating-point constants 0.0, 0.5, 1.0, 2.0, 3.0, + 4.0, 5.0 or 10.0 + + `G' + Floating-point constant that would satisfy the constraint `F' + if it were negated + + `I' + Integer that is valid as an immediate operand in a data + processing instruction. That is, an integer in the range 0 + to 255 rotated by a multiple of 2 + + `J' + Integer in the range -4095 to 4095 + + `K' + Integer that satisfies constraint `I' when inverted (ones + complement) + + `L' + Integer that satisfies constraint `I' when negated (twos + complement) + + `M' + Integer in the range 0 to 32 + + `Q' + A memory reference where the exact address is in a single + register (``m'' is preferable for `asm' statements) + + `R' + An item in the constant pool + + `S' + A symbol in the text segment of the current file + + `Uv' + A memory reference suitable for VFP load/store insns + (reg+constant offset) + + `Uy' + A memory reference suitable for iWMMXt load/store + instructions. + + `Uq' + A memory reference suitable for the ARMv4 ldrsb instruction. + +_AVR family--`config/avr/constraints.md'_ + + `l' + Registers from r0 to r15 + + `a' + Registers from r16 to r23 + + `d' + Registers from r16 to r31 + + `w' + Registers from r24 to r31. These registers can be used in + `adiw' command + + `e' + Pointer register (r26-r31) + + `b' + Base pointer register (r28-r31) + + `q' + Stack pointer register (SPH:SPL) + + `t' + Temporary register r0 + + `x' + Register pair X (r27:r26) + + `y' + Register pair Y (r29:r28) + + `z' + Register pair Z (r31:r30) + + `I' + Constant greater than -1, less than 64 + + `J' + Constant greater than -64, less than 1 + + `K' + Constant integer 2 + + `L' + Constant integer 0 + + `M' + Constant that fits in 8 bits + + `N' + Constant integer -1 + + `O' + Constant integer 8, 16, or 24 + + `P' + Constant integer 1 + + `G' + A floating point constant 0.0 + + `R' + Integer constant in the range -6 ... 5. + + `Q' + A memory address based on Y or Z pointer with displacement. + +_CRX Architecture--`config/crx/crx.h'_ + + `b' + Registers from r0 to r14 (registers without stack pointer) + + `l' + Register r16 (64-bit accumulator lo register) + + `h' + Register r17 (64-bit accumulator hi register) + + `k' + Register pair r16-r17. (64-bit accumulator lo-hi pair) + + `I' + Constant that fits in 3 bits + + `J' + Constant that fits in 4 bits + + `K' + Constant that fits in 5 bits + + `L' + Constant that is one of -1, 4, -4, 7, 8, 12, 16, 20, 32, 48 + + `G' + Floating point constant that is legal for store immediate + +_Hewlett-Packard PA-RISC--`config/pa/pa.h'_ + + `a' + General register 1 + + `f' + Floating point register + + `q' + Shift amount register + + `x' + Floating point register (deprecated) + + `y' + Upper floating point register (32-bit), floating point + register (64-bit) + + `Z' + Any register + + `I' + Signed 11-bit integer constant + + `J' + Signed 14-bit integer constant + + `K' + Integer constant that can be deposited with a `zdepi' + instruction + + `L' + Signed 5-bit integer constant + + `M' + Integer constant 0 + + `N' + Integer constant that can be loaded with a `ldil' instruction + + `O' + Integer constant whose value plus one is a power of 2 + + `P' + Integer constant that can be used for `and' operations in + `depi' and `extru' instructions + + `S' + Integer constant 31 + + `U' + Integer constant 63 + + `G' + Floating-point constant 0.0 + + `A' + A `lo_sum' data-linkage-table memory operand + + `Q' + A memory operand that can be used as the destination operand + of an integer store instruction + + `R' + A scaled or unscaled indexed memory operand + + `T' + A memory operand for floating-point loads and stores + + `W' + A register indirect memory operand + +_picoChip family--`picochip.h'_ + + `k' + Stack register. + + `f' + Pointer register. A register which can be used to access + memory without supplying an offset. Any other register can + be used to access memory, but will need a constant offset. + In the case of the offset being zero, it is more efficient to + use a pointer register, since this reduces code size. + + `t' + A twin register. A register which may be paired with an + adjacent register to create a 32-bit register. + + `a' + Any absolute memory address (e.g., symbolic constant, symbolic + constant + offset). + + `I' + 4-bit signed integer. + + `J' + 4-bit unsigned integer. + + `K' + 8-bit signed integer. + + `M' + Any constant whose absolute value is no greater than 4-bits. + + `N' + 10-bit signed integer + + `O' + 16-bit signed integer. + + +_PowerPC and IBM RS6000--`config/rs6000/rs6000.h'_ + + `b' + Address base register + + `d' + Floating point register (containing 64-bit value) + + `f' + Floating point register (containing 32-bit value) + + `v' + Altivec vector register + + `wd' + VSX vector register to hold vector double data + + `wf' + VSX vector register to hold vector float data + + `ws' + VSX vector register to hold scalar float data + + `wa' + Any VSX register + + `h' + `MQ', `CTR', or `LINK' register + + `q' + `MQ' register + + `c' + `CTR' register + + `l' + `LINK' register + + `x' + `CR' register (condition register) number 0 + + `y' + `CR' register (condition register) + + `z' + `XER[CA]' carry bit (part of the XER register) + + `I' + Signed 16-bit constant + + `J' + Unsigned 16-bit constant shifted left 16 bits (use `L' + instead for `SImode' constants) + + `K' + Unsigned 16-bit constant + + `L' + Signed 16-bit constant shifted left 16 bits + + `M' + Constant larger than 31 + + `N' + Exact power of 2 + + `O' + Zero + + `P' + Constant whose negation is a signed 16-bit constant + + `G' + Floating point constant that can be loaded into a register + with one instruction per word + + `H' + Integer/Floating point constant that can be loaded into a + register using three instructions + + `m' + Memory operand. Normally, `m' does not allow addresses that + update the base register. If `<' or `>' constraint is also + used, they are allowed and therefore on PowerPC targets in + that case it is only safe to use `m<>' in an `asm' statement + if that `asm' statement accesses the operand exactly once. + The `asm' statement must also use `%U<OPNO>' as a placeholder + for the "update" flag in the corresponding load or store + instruction. For example: + + asm ("st%U0 %1,%0" : "=m<>" (mem) : "r" (val)); + + is correct but: + + asm ("st %1,%0" : "=m<>" (mem) : "r" (val)); + + is not. + + `es' + A "stable" memory operand; that is, one which does not + include any automodification of the base register. This used + to be useful when `m' allowed automodification of the base + register, but as those are now only allowed when `<' or `>' + is used, `es' is basically the same as `m' without `<' and + `>'. + + `Q' + Memory operand that is an offset from a register (it is + usually better to use `m' or `es' in `asm' statements) + + `Z' + Memory operand that is an indexed or indirect from a register + (it is usually better to use `m' or `es' in `asm' statements) + + `R' + AIX TOC entry + + `a' + Address operand that is an indexed or indirect from a + register (`p' is preferable for `asm' statements) + + `S' + Constant suitable as a 64-bit mask operand + + `T' + Constant suitable as a 32-bit mask operand + + `U' + System V Release 4 small data area reference + + `t' + AND masks that can be performed by two rldic{l, r} + instructions + + `W' + Vector constant that does not require memory + + `j' + Vector constant that is all zeros. + + +_Intel 386--`config/i386/constraints.md'_ + + `R' + Legacy register--the eight integer registers available on all + i386 processors (`a', `b', `c', `d', `si', `di', `bp', `sp'). + + `q' + Any register accessible as `Rl'. In 32-bit mode, `a', `b', + `c', and `d'; in 64-bit mode, any integer register. + + `Q' + Any register accessible as `Rh': `a', `b', `c', and `d'. + + `l' + Any register that can be used as the index in a base+index + memory access: that is, any general register except the stack + pointer. + + `a' + The `a' register. + + `b' + The `b' register. + + `c' + The `c' register. + + `d' + The `d' register. + + `S' + The `si' register. + + `D' + The `di' register. + + `A' + The `a' and `d' registers. This class is used for + instructions that return double word results in the `ax:dx' + register pair. Single word values will be allocated either + in `ax' or `dx'. For example on i386 the following + implements `rdtsc': + + unsigned long long rdtsc (void) + { + unsigned long long tick; + __asm__ __volatile__("rdtsc":"=A"(tick)); + return tick; + } + + This is not correct on x86_64 as it would allocate tick in + either `ax' or `dx'. You have to use the following variant + instead: + + unsigned long long rdtsc (void) + { + unsigned int tickl, tickh; + __asm__ __volatile__("rdtsc":"=a"(tickl),"=d"(tickh)); + return ((unsigned long long)tickh << 32)|tickl; + } + + `f' + Any 80387 floating-point (stack) register. + + `t' + Top of 80387 floating-point stack (`%st(0)'). + + `u' + Second from top of 80387 floating-point stack (`%st(1)'). + + `y' + Any MMX register. + + `x' + Any SSE register. + + `Yz' + First SSE register (`%xmm0'). + + `Y2' + Any SSE register, when SSE2 is enabled. + + `Yi' + Any SSE register, when SSE2 and inter-unit moves are enabled. + + `Ym' + Any MMX register, when inter-unit moves are enabled. + + `I' + Integer constant in the range 0 ... 31, for 32-bit shifts. + + `J' + Integer constant in the range 0 ... 63, for 64-bit shifts. + + `K' + Signed 8-bit integer constant. + + `L' + `0xFF' or `0xFFFF', for andsi as a zero-extending move. + + `M' + 0, 1, 2, or 3 (shifts for the `lea' instruction). + + `N' + Unsigned 8-bit integer constant (for `in' and `out' + instructions). + + `O' + Integer constant in the range 0 ... 127, for 128-bit shifts. + + `G' + Standard 80387 floating point constant. + + `C' + Standard SSE floating point constant. + + `e' + 32-bit signed integer constant, or a symbolic reference known + to fit that range (for immediate operands in sign-extending + x86-64 instructions). + + `Z' + 32-bit unsigned integer constant, or a symbolic reference + known to fit that range (for immediate operands in + zero-extending x86-64 instructions). + + +_Intel IA-64--`config/ia64/ia64.h'_ + + `a' + General register `r0' to `r3' for `addl' instruction + + `b' + Branch register + + `c' + Predicate register (`c' as in "conditional") + + `d' + Application register residing in M-unit + + `e' + Application register residing in I-unit + + `f' + Floating-point register + + `m' + Memory operand. If used together with `<' or `>', the + operand can have postincrement and postdecrement which + require printing with `%Pn' on IA-64. + + `G' + Floating-point constant 0.0 or 1.0 + + `I' + 14-bit signed integer constant + + `J' + 22-bit signed integer constant + + `K' + 8-bit signed integer constant for logical instructions + + `L' + 8-bit adjusted signed integer constant for compare pseudo-ops + + `M' + 6-bit unsigned integer constant for shift counts + + `N' + 9-bit signed integer constant for load and store + postincrements + + `O' + The constant zero + + `P' + 0 or -1 for `dep' instruction + + `Q' + Non-volatile memory for floating-point loads and stores + + `R' + Integer constant in the range 1 to 4 for `shladd' instruction + + `S' + Memory operand except postincrement and postdecrement. This + is now roughly the same as `m' when not used together with `<' + or `>'. + +_FRV--`config/frv/frv.h'_ + + `a' + Register in the class `ACC_REGS' (`acc0' to `acc7'). + + `b' + Register in the class `EVEN_ACC_REGS' (`acc0' to `acc7'). + + `c' + Register in the class `CC_REGS' (`fcc0' to `fcc3' and `icc0' + to `icc3'). + + `d' + Register in the class `GPR_REGS' (`gr0' to `gr63'). + + `e' + Register in the class `EVEN_REGS' (`gr0' to `gr63'). Odd + registers are excluded not in the class but through the use + of a machine mode larger than 4 bytes. + + `f' + Register in the class `FPR_REGS' (`fr0' to `fr63'). + + `h' + Register in the class `FEVEN_REGS' (`fr0' to `fr63'). Odd + registers are excluded not in the class but through the use + of a machine mode larger than 4 bytes. + + `l' + Register in the class `LR_REG' (the `lr' register). + + `q' + Register in the class `QUAD_REGS' (`gr2' to `gr63'). + Register numbers not divisible by 4 are excluded not in the + class but through the use of a machine mode larger than 8 + bytes. + + `t' + Register in the class `ICC_REGS' (`icc0' to `icc3'). + + `u' + Register in the class `FCC_REGS' (`fcc0' to `fcc3'). + + `v' + Register in the class `ICR_REGS' (`cc4' to `cc7'). + + `w' + Register in the class `FCR_REGS' (`cc0' to `cc3'). + + `x' + Register in the class `QUAD_FPR_REGS' (`fr0' to `fr63'). + Register numbers not divisible by 4 are excluded not in the + class but through the use of a machine mode larger than 8 + bytes. + + `z' + Register in the class `SPR_REGS' (`lcr' and `lr'). + + `A' + Register in the class `QUAD_ACC_REGS' (`acc0' to `acc7'). + + `B' + Register in the class `ACCG_REGS' (`accg0' to `accg7'). + + `C' + Register in the class `CR_REGS' (`cc0' to `cc7'). + + `G' + Floating point constant zero + + `I' + 6-bit signed integer constant + + `J' + 10-bit signed integer constant + + `L' + 16-bit signed integer constant + + `M' + 16-bit unsigned integer constant + + `N' + 12-bit signed integer constant that is negative--i.e. in the + range of -2048 to -1 + + `O' + Constant zero + + `P' + 12-bit signed integer constant that is greater than + zero--i.e. in the range of 1 to 2047. + + +_Blackfin family--`config/bfin/constraints.md'_ + + `a' + P register + + `d' + D register + + `z' + A call clobbered P register. + + `qN' + A single register. If N is in the range 0 to 7, the + corresponding D register. If it is `A', then the register P0. + + `D' + Even-numbered D register + + `W' + Odd-numbered D register + + `e' + Accumulator register. + + `A' + Even-numbered accumulator register. + + `B' + Odd-numbered accumulator register. + + `b' + I register + + `v' + B register + + `f' + M register + + `c' + Registers used for circular buffering, i.e. I, B, or L + registers. + + `C' + The CC register. + + `t' + LT0 or LT1. + + `k' + LC0 or LC1. + + `u' + LB0 or LB1. + + `x' + Any D, P, B, M, I or L register. + + `y' + Additional registers typically used only in prologues and + epilogues: RETS, RETN, RETI, RETX, RETE, ASTAT, SEQSTAT and + USP. + + `w' + Any register except accumulators or CC. + + `Ksh' + Signed 16 bit integer (in the range -32768 to 32767) + + `Kuh' + Unsigned 16 bit integer (in the range 0 to 65535) + + `Ks7' + Signed 7 bit integer (in the range -64 to 63) + + `Ku7' + Unsigned 7 bit integer (in the range 0 to 127) + + `Ku5' + Unsigned 5 bit integer (in the range 0 to 31) + + `Ks4' + Signed 4 bit integer (in the range -8 to 7) + + `Ks3' + Signed 3 bit integer (in the range -3 to 4) + + `Ku3' + Unsigned 3 bit integer (in the range 0 to 7) + + `PN' + Constant N, where N is a single-digit constant in the range 0 + to 4. + + `PA' + An integer equal to one of the MACFLAG_XXX constants that is + suitable for use with either accumulator. + + `PB' + An integer equal to one of the MACFLAG_XXX constants that is + suitable for use only with accumulator A1. + + `M1' + Constant 255. + + `M2' + Constant 65535. + + `J' + An integer constant with exactly a single bit set. + + `L' + An integer constant with all bits set except exactly one. + + `H' + + `Q' + Any SYMBOL_REF. + +_M32C--`config/m32c/m32c.c'_ + + `Rsp' + `Rfb' + `Rsb' + `$sp', `$fb', `$sb'. + + `Rcr' + Any control register, when they're 16 bits wide (nothing if + control registers are 24 bits wide) + + `Rcl' + Any control register, when they're 24 bits wide. + + `R0w' + `R1w' + `R2w' + `R3w' + $r0, $r1, $r2, $r3. + + `R02' + $r0 or $r2, or $r2r0 for 32 bit values. + + `R13' + $r1 or $r3, or $r3r1 for 32 bit values. + + `Rdi' + A register that can hold a 64 bit value. + + `Rhl' + $r0 or $r1 (registers with addressable high/low bytes) + + `R23' + $r2 or $r3 + + `Raa' + Address registers + + `Raw' + Address registers when they're 16 bits wide. + + `Ral' + Address registers when they're 24 bits wide. + + `Rqi' + Registers that can hold QI values. + + `Rad' + Registers that can be used with displacements ($a0, $a1, $sb). + + `Rsi' + Registers that can hold 32 bit values. + + `Rhi' + Registers that can hold 16 bit values. + + `Rhc' + Registers chat can hold 16 bit values, including all control + registers. + + `Rra' + $r0 through R1, plus $a0 and $a1. + + `Rfl' + The flags register. + + `Rmm' + The memory-based pseudo-registers $mem0 through $mem15. + + `Rpi' + Registers that can hold pointers (16 bit registers for r8c, + m16c; 24 bit registers for m32cm, m32c). + + `Rpa' + Matches multiple registers in a PARALLEL to form a larger + register. Used to match function return values. + + `Is3' + -8 ... 7 + + `IS1' + -128 ... 127 + + `IS2' + -32768 ... 32767 + + `IU2' + 0 ... 65535 + + `In4' + -8 ... -1 or 1 ... 8 + + `In5' + -16 ... -1 or 1 ... 16 + + `In6' + -32 ... -1 or 1 ... 32 + + `IM2' + -65536 ... -1 + + `Ilb' + An 8 bit value with exactly one bit set. + + `Ilw' + A 16 bit value with exactly one bit set. + + `Sd' + The common src/dest memory addressing modes. + + `Sa' + Memory addressed using $a0 or $a1. + + `Si' + Memory addressed with immediate addresses. + + `Ss' + Memory addressed using the stack pointer ($sp). + + `Sf' + Memory addressed using the frame base register ($fb). + + `Ss' + Memory addressed using the small base register ($sb). + + `S1' + $r1h + +_MeP--`config/mep/constraints.md'_ + + `a' + The $sp register. + + `b' + The $tp register. + + `c' + Any control register. + + `d' + Either the $hi or the $lo register. + + `em' + Coprocessor registers that can be directly loaded ($c0-$c15). + + `ex' + Coprocessor registers that can be moved to each other. + + `er' + Coprocessor registers that can be moved to core registers. + + `h' + The $hi register. + + `j' + The $rpc register. + + `l' + The $lo register. + + `t' + Registers which can be used in $tp-relative addressing. + + `v' + The $gp register. + + `x' + The coprocessor registers. + + `y' + The coprocessor control registers. + + `z' + The $0 register. + + `A' + User-defined register set A. + + `B' + User-defined register set B. + + `C' + User-defined register set C. + + `D' + User-defined register set D. + + `I' + Offsets for $gp-rel addressing. + + `J' + Constants that can be used directly with boolean insns. + + `K' + Constants that can be moved directly to registers. + + `L' + Small constants that can be added to registers. + + `M' + Long shift counts. + + `N' + Small constants that can be compared to registers. + + `O' + Constants that can be loaded into the top half of registers. + + `S' + Signed 8-bit immediates. + + `T' + Symbols encoded for $tp-rel or $gp-rel addressing. + + `U' + Non-constant addresses for loading/saving coprocessor + registers. + + `W' + The top half of a symbol's value. + + `Y' + A register indirect address without offset. + + `Z' + Symbolic references to the control bus. + + +_MicroBlaze--`config/microblaze/constraints.md'_ + + `d' + A general register (`r0' to `r31'). + + `z' + A status register (`rmsr', `$fcc1' to `$fcc7'). + + +_MIPS--`config/mips/constraints.md'_ + + `d' + An address register. This is equivalent to `r' unless + generating MIPS16 code. + + `f' + A floating-point register (if available). + + `h' + Formerly the `hi' register. This constraint is no longer + supported. + + `l' + The `lo' register. Use this register to store values that are + no bigger than a word. + + `x' + The concatenated `hi' and `lo' registers. Use this register + to store doubleword values. + + `c' + A register suitable for use in an indirect jump. This will + always be `$25' for `-mabicalls'. + + `v' + Register `$3'. Do not use this constraint in new code; it is + retained only for compatibility with glibc. + + `y' + Equivalent to `r'; retained for backwards compatibility. + + `z' + A floating-point condition code register. + + `I' + A signed 16-bit constant (for arithmetic instructions). + + `J' + Integer zero. + + `K' + An unsigned 16-bit constant (for logic instructions). + + `L' + A signed 32-bit constant in which the lower 16 bits are zero. + Such constants can be loaded using `lui'. + + `M' + A constant that cannot be loaded using `lui', `addiu' or + `ori'. + + `N' + A constant in the range -65535 to -1 (inclusive). + + `O' + A signed 15-bit constant. + + `P' + A constant in the range 1 to 65535 (inclusive). + + `G' + Floating-point zero. + + `R' + An address that can be used in a non-macro load or store. + +_Motorola 680x0--`config/m68k/constraints.md'_ + + `a' + Address register + + `d' + Data register + + `f' + 68881 floating-point register, if available + + `I' + Integer in the range 1 to 8 + + `J' + 16-bit signed number + + `K' + Signed number whose magnitude is greater than 0x80 + + `L' + Integer in the range -8 to -1 + + `M' + Signed number whose magnitude is greater than 0x100 + + `N' + Range 24 to 31, rotatert:SI 8 to 1 expressed as rotate + + `O' + 16 (for rotate using swap) + + `P' + Range 8 to 15, rotatert:HI 8 to 1 expressed as rotate + + `R' + Numbers that mov3q can handle + + `G' + Floating point constant that is not a 68881 constant + + `S' + Operands that satisfy 'm' when -mpcrel is in effect + + `T' + Operands that satisfy 's' when -mpcrel is not in effect + + `Q' + Address register indirect addressing mode + + `U' + Register offset addressing + + `W' + const_call_operand + + `Cs' + symbol_ref or const + + `Ci' + const_int + + `C0' + const_int 0 + + `Cj' + Range of signed numbers that don't fit in 16 bits + + `Cmvq' + Integers valid for mvq + + `Capsw' + Integers valid for a moveq followed by a swap + + `Cmvz' + Integers valid for mvz + + `Cmvs' + Integers valid for mvs + + `Ap' + push_operand + + `Ac' + Non-register operands allowed in clr + + +_Motorola 68HC11 & 68HC12 families--`config/m68hc11/m68hc11.h'_ + + `a' + Register `a' + + `b' + Register `b' + + `d' + Register `d' + + `q' + An 8-bit register + + `t' + Temporary soft register _.tmp + + `u' + A soft register _.d1 to _.d31 + + `w' + Stack pointer register + + `x' + Register `x' + + `y' + Register `y' + + `z' + Pseudo register `z' (replaced by `x' or `y' at the end) + + `A' + An address register: x, y or z + + `B' + An address register: x or y + + `D' + Register pair (x:d) to form a 32-bit value + + `L' + Constants in the range -65536 to 65535 + + `M' + Constants whose 16-bit low part is zero + + `N' + Constant integer 1 or -1 + + `O' + Constant integer 16 + + `P' + Constants in the range -8 to 2 + + +_Moxie--`config/moxie/constraints.md'_ + + `A' + An absolute address + + `B' + An offset address + + `W' + A register indirect memory operand + + `I' + A constant in the range of 0 to 255. + + `N' + A constant in the range of 0 to -255. + + +_PDP-11--`config/pdp11/constraints.md'_ + + `a' + Floating point registers AC0 through AC3. These can be + loaded from/to memory with a single instruction. + + `d' + Odd numbered general registers (R1, R3, R5). These are used + for 16-bit multiply operations. + + `f' + Any of the floating point registers (AC0 through AC5). + + `G' + Floating point constant 0. + + `I' + An integer constant that fits in 16 bits. + + `J' + An integer constant whose low order 16 bits are zero. + + `K' + An integer constant that does not meet the constraints for + codes `I' or `J'. + + `L' + The integer constant 1. + + `M' + The integer constant -1. + + `N' + The integer constant 0. + + `O' + Integer constants -4 through -1 and 1 through 4; shifts by + these amounts are handled as multiple single-bit shifts + rather than a single variable-length shift. + + `Q' + A memory reference which requires an additional word (address + or offset) after the opcode. + + `R' + A memory reference that is encoded within the opcode. + + +_RX--`config/rx/constraints.md'_ + + `Q' + An address which does not involve register indirect + addressing or pre/post increment/decrement addressing. + + `Symbol' + A symbol reference. + + `Int08' + A constant in the range -256 to 255, inclusive. + + `Sint08' + A constant in the range -128 to 127, inclusive. + + `Sint16' + A constant in the range -32768 to 32767, inclusive. + + `Sint24' + A constant in the range -8388608 to 8388607, inclusive. + + `Uint04' + A constant in the range 0 to 15, inclusive. + + +_SPARC--`config/sparc/sparc.h'_ + + `f' + Floating-point register on the SPARC-V8 architecture and + lower floating-point register on the SPARC-V9 architecture. + + `e' + Floating-point register. It is equivalent to `f' on the + SPARC-V8 architecture and contains both lower and upper + floating-point registers on the SPARC-V9 architecture. + + `c' + Floating-point condition code register. + + `d' + Lower floating-point register. It is only valid on the + SPARC-V9 architecture when the Visual Instruction Set is + available. + + `b' + Floating-point register. It is only valid on the SPARC-V9 + architecture when the Visual Instruction Set is available. + + `h' + 64-bit global or out register for the SPARC-V8+ architecture. + + `D' + A vector constant + + `I' + Signed 13-bit constant + + `J' + Zero + + `K' + 32-bit constant with the low 12 bits clear (a constant that + can be loaded with the `sethi' instruction) + + `L' + A constant in the range supported by `movcc' instructions + + `M' + A constant in the range supported by `movrcc' instructions + + `N' + Same as `K', except that it verifies that bits that are not + in the lower 32-bit range are all zero. Must be used instead + of `K' for modes wider than `SImode' + + `O' + The constant 4096 + + `G' + Floating-point zero + + `H' + Signed 13-bit constant, sign-extended to 32 or 64 bits + + `Q' + Floating-point constant whose integral representation can be + moved into an integer register using a single sethi + instruction + + `R' + Floating-point constant whose integral representation can be + moved into an integer register using a single mov instruction + + `S' + Floating-point constant whose integral representation can be + moved into an integer register using a high/lo_sum + instruction sequence + + `T' + Memory address aligned to an 8-byte boundary + + `U' + Even register + + `W' + Memory address for `e' constraint registers + + `Y' + Vector zero + + +_SPU--`config/spu/spu.h'_ + + `a' + An immediate which can be loaded with the il/ila/ilh/ilhu + instructions. const_int is treated as a 64 bit value. + + `c' + An immediate for and/xor/or instructions. const_int is + treated as a 64 bit value. + + `d' + An immediate for the `iohl' instruction. const_int is + treated as a 64 bit value. + + `f' + An immediate which can be loaded with `fsmbi'. + + `A' + An immediate which can be loaded with the il/ila/ilh/ilhu + instructions. const_int is treated as a 32 bit value. + + `B' + An immediate for most arithmetic instructions. const_int is + treated as a 32 bit value. + + `C' + An immediate for and/xor/or instructions. const_int is + treated as a 32 bit value. + + `D' + An immediate for the `iohl' instruction. const_int is + treated as a 32 bit value. + + `I' + A constant in the range [-64, 63] for shift/rotate + instructions. + + `J' + An unsigned 7-bit constant for conversion/nop/channel + instructions. + + `K' + A signed 10-bit constant for most arithmetic instructions. + + `M' + A signed 16 bit immediate for `stop'. + + `N' + An unsigned 16-bit constant for `iohl' and `fsmbi'. + + `O' + An unsigned 7-bit constant whose 3 least significant bits are + 0. + + `P' + An unsigned 3-bit constant for 16-byte rotates and shifts + + `R' + Call operand, reg, for indirect calls + + `S' + Call operand, symbol, for relative calls. + + `T' + Call operand, const_int, for absolute calls. + + `U' + An immediate which can be loaded with the il/ila/ilh/ilhu + instructions. const_int is sign extended to 128 bit. + + `W' + An immediate for shift and rotate instructions. const_int is + treated as a 32 bit value. + + `Y' + An immediate for and/xor/or instructions. const_int is sign + extended as a 128 bit. + + `Z' + An immediate for the `iohl' instruction. const_int is sign + extended to 128 bit. + + +_S/390 and zSeries--`config/s390/s390.h'_ + + `a' + Address register (general purpose register except r0) + + `c' + Condition code register + + `d' + Data register (arbitrary general purpose register) + + `f' + Floating-point register + + `I' + Unsigned 8-bit constant (0-255) + + `J' + Unsigned 12-bit constant (0-4095) + + `K' + Signed 16-bit constant (-32768-32767) + + `L' + Value appropriate as displacement. + `(0..4095)' + for short displacement + + `(-524288..524287)' + for long displacement + + `M' + Constant integer with a value of 0x7fffffff. + + `N' + Multiple letter constraint followed by 4 parameter letters. + `0..9:' + number of the part counting from most to least + significant + + `H,Q:' + mode of the part + + `D,S,H:' + mode of the containing operand + + `0,F:' + value of the other parts (F--all bits set) + The constraint matches if the specified part of a constant + has a value different from its other parts. + + `Q' + Memory reference without index register and with short + displacement. + + `R' + Memory reference with index register and short displacement. + + `S' + Memory reference without index register but with long + displacement. + + `T' + Memory reference with index register and long displacement. + + `U' + Pointer with short displacement. + + `W' + Pointer with long displacement. + + `Y' + Shift count operand. + + +_Score family--`config/score/score.h'_ + + `d' + Registers from r0 to r32. + + `e' + Registers from r0 to r16. + + `t' + r8--r11 or r22--r27 registers. + + `h' + hi register. + + `l' + lo register. + + `x' + hi + lo register. + + `q' + cnt register. + + `y' + lcb register. + + `z' + scb register. + + `a' + cnt + lcb + scb register. + + `c' + cr0--cr15 register. + + `b' + cp1 registers. + + `f' + cp2 registers. + + `i' + cp3 registers. + + `j' + cp1 + cp2 + cp3 registers. + + `I' + High 16-bit constant (32-bit constant with 16 LSBs zero). + + `J' + Unsigned 5 bit integer (in the range 0 to 31). + + `K' + Unsigned 16 bit integer (in the range 0 to 65535). + + `L' + Signed 16 bit integer (in the range -32768 to 32767). + + `M' + Unsigned 14 bit integer (in the range 0 to 16383). + + `N' + Signed 14 bit integer (in the range -8192 to 8191). + + `Z' + Any SYMBOL_REF. + +_Xstormy16--`config/stormy16/stormy16.h'_ + + `a' + Register r0. + + `b' + Register r1. + + `c' + Register r2. + + `d' + Register r8. + + `e' + Registers r0 through r7. + + `t' + Registers r0 and r1. + + `y' + The carry register. + + `z' + Registers r8 and r9. + + `I' + A constant between 0 and 3 inclusive. + + `J' + A constant that has exactly one bit set. + + `K' + A constant that has exactly one bit clear. + + `L' + A constant between 0 and 255 inclusive. + + `M' + A constant between -255 and 0 inclusive. + + `N' + A constant between -3 and 0 inclusive. + + `O' + A constant between 1 and 4 inclusive. + + `P' + A constant between -4 and -1 inclusive. + + `Q' + A memory reference that is a stack push. + + `R' + A memory reference that is a stack pop. + + `S' + A memory reference that refers to a constant address of known + value. + + `T' + The register indicated by Rx (not implemented yet). + + `U' + A constant that is not between 2 and 15 inclusive. + + `Z' + The constant 0. + + +_Xtensa--`config/xtensa/constraints.md'_ + + `a' + General-purpose 32-bit register + + `b' + One-bit boolean register + + `A' + MAC16 40-bit accumulator register + + `I' + Signed 12-bit integer constant, for use in MOVI instructions + + `J' + Signed 8-bit integer constant, for use in ADDI instructions + + `K' + Integer constant valid for BccI instructions + + `L' + Unsigned constant valid for BccUI instructions + + + + +File: gccint.info, Node: Disable Insn Alternatives, Next: Machine Constraints, Prev: Modifiers, Up: Constraints + +16.8.6 Disable insn alternatives using the `enabled' attribute +-------------------------------------------------------------- + +The `enabled' insn attribute may be used to disable certain insn +alternatives for machine-specific reasons. This is useful when adding +new instructions to an existing pattern which are only available for +certain cpu architecture levels as specified with the `-march=' option. + + If an insn alternative is disabled, then it will never be used. The +compiler treats the constraints for the disabled alternative as +unsatisfiable. + + In order to make use of the `enabled' attribute a back end has to add +in the machine description files: + + 1. A definition of the `enabled' insn attribute. The attribute is + defined as usual using the `define_attr' command. This definition + should be based on other insn attributes and/or target flags. The + `enabled' attribute is a numeric attribute and should evaluate to + `(const_int 1)' for an enabled alternative and to `(const_int 0)' + otherwise. + + 2. A definition of another insn attribute used to describe for what + reason an insn alternative might be available or not. E.g. + `cpu_facility' as in the example below. + + 3. An assignment for the second attribute to each insn definition + combining instructions which are not all available under the same + circumstances. (Note: It obviously only makes sense for + definitions with more than one alternative. Otherwise the insn + pattern should be disabled or enabled using the insn condition.) + + E.g. the following two patterns could easily be merged using the +`enabled' attribute: + + + (define_insn "*movdi_old" + [(set (match_operand:DI 0 "register_operand" "=d") + (match_operand:DI 1 "register_operand" " d"))] + "!TARGET_NEW" + "lgr %0,%1") + + (define_insn "*movdi_new" + [(set (match_operand:DI 0 "register_operand" "=d,f,d") + (match_operand:DI 1 "register_operand" " d,d,f"))] + "TARGET_NEW" + "@ + lgr %0,%1 + ldgr %0,%1 + lgdr %0,%1") + + to: + + + (define_insn "*movdi_combined" + [(set (match_operand:DI 0 "register_operand" "=d,f,d") + (match_operand:DI 1 "register_operand" " d,d,f"))] + "" + "@ + lgr %0,%1 + ldgr %0,%1 + lgdr %0,%1" + [(set_attr "cpu_facility" "*,new,new")]) + + with the `enabled' attribute defined like this: + + + (define_attr "cpu_facility" "standard,new" (const_string "standard")) + + (define_attr "enabled" "" + (cond [(eq_attr "cpu_facility" "standard") (const_int 1) + (and (eq_attr "cpu_facility" "new") + (ne (symbol_ref "TARGET_NEW") (const_int 0))) + (const_int 1)] + (const_int 0))) + + +File: gccint.info, Node: Define Constraints, Next: C Constraint Interface, Prev: Machine Constraints, Up: Constraints + +16.8.7 Defining Machine-Specific Constraints +-------------------------------------------- + +Machine-specific constraints fall into two categories: register and +non-register constraints. Within the latter category, constraints +which allow subsets of all possible memory or address operands should +be specially marked, to give `reload' more information. + + Machine-specific constraints can be given names of arbitrary length, +but they must be entirely composed of letters, digits, underscores +(`_'), and angle brackets (`< >'). Like C identifiers, they must begin +with a letter or underscore. + + In order to avoid ambiguity in operand constraint strings, no +constraint can have a name that begins with any other constraint's +name. For example, if `x' is defined as a constraint name, `xy' may +not be, and vice versa. As a consequence of this rule, no constraint +may begin with one of the generic constraint letters: `E F V X g i m n +o p r s'. + + Register constraints correspond directly to register classes. *Note +Register Classes::. There is thus not much flexibility in their +definitions. + + -- MD Expression: define_register_constraint name regclass docstring + All three arguments are string constants. NAME is the name of the + constraint, as it will appear in `match_operand' expressions. If + NAME is a multi-letter constraint its length shall be the same for + all constraints starting with the same letter. REGCLASS can be + either the name of the corresponding register class (*note + Register Classes::), or a C expression which evaluates to the + appropriate register class. If it is an expression, it must have + no side effects, and it cannot look at the operand. The usual use + of expressions is to map some register constraints to `NO_REGS' + when the register class is not available on a given + subarchitecture. + + DOCSTRING is a sentence documenting the meaning of the constraint. + Docstrings are explained further below. + + Non-register constraints are more like predicates: the constraint +definition gives a Boolean expression which indicates whether the +constraint matches. + + -- MD Expression: define_constraint name docstring exp + The NAME and DOCSTRING arguments are the same as for + `define_register_constraint', but note that the docstring comes + immediately after the name for these expressions. EXP is an RTL + expression, obeying the same rules as the RTL expressions in + predicate definitions. *Note Defining Predicates::, for details. + If it evaluates true, the constraint matches; if it evaluates + false, it doesn't. Constraint expressions should indicate which + RTL codes they might match, just like predicate expressions. + + `match_test' C expressions have access to the following variables: + + OP + The RTL object defining the operand. + + MODE + The machine mode of OP. + + IVAL + `INTVAL (OP)', if OP is a `const_int'. + + HVAL + `CONST_DOUBLE_HIGH (OP)', if OP is an integer `const_double'. + + LVAL + `CONST_DOUBLE_LOW (OP)', if OP is an integer `const_double'. + + RVAL + `CONST_DOUBLE_REAL_VALUE (OP)', if OP is a floating-point + `const_double'. + + The *VAL variables should only be used once another piece of the + expression has verified that OP is the appropriate kind of RTL + object. + + Most non-register constraints should be defined with +`define_constraint'. The remaining two definition expressions are only +appropriate for constraints that should be handled specially by +`reload' if they fail to match. + + -- MD Expression: define_memory_constraint name docstring exp + Use this expression for constraints that match a subset of all + memory operands: that is, `reload' can make them match by + converting the operand to the form `(mem (reg X))', where X is a + base register (from the register class specified by + `BASE_REG_CLASS', *note Register Classes::). + + For example, on the S/390, some instructions do not accept + arbitrary memory references, but only those that do not make use + of an index register. The constraint letter `Q' is defined to + represent a memory address of this type. If `Q' is defined with + `define_memory_constraint', a `Q' constraint can handle any memory + operand, because `reload' knows it can simply copy the memory + address into a base register if required. This is analogous to + the way an `o' constraint can handle any memory operand. + + The syntax and semantics are otherwise identical to + `define_constraint'. + + -- MD Expression: define_address_constraint name docstring exp + Use this expression for constraints that match a subset of all + address operands: that is, `reload' can make the constraint match + by converting the operand to the form `(reg X)', again with X a + base register. + + Constraints defined with `define_address_constraint' can only be + used with the `address_operand' predicate, or machine-specific + predicates that work the same way. They are treated analogously to + the generic `p' constraint. + + The syntax and semantics are otherwise identical to + `define_constraint'. + + For historical reasons, names beginning with the letters `G H' are +reserved for constraints that match only `const_double's, and names +beginning with the letters `I J K L M N O P' are reserved for +constraints that match only `const_int's. This may change in the +future. For the time being, constraints with these names must be +written in a stylized form, so that `genpreds' can tell you did it +correctly: + + (define_constraint "[GHIJKLMNOP]..." + "DOC..." + (and (match_code "const_int") ; `const_double' for G/H + CONDITION...)) ; usually a `match_test' + + It is fine to use names beginning with other letters for constraints +that match `const_double's or `const_int's. + + Each docstring in a constraint definition should be one or more +complete sentences, marked up in Texinfo format. _They are currently +unused._ In the future they will be copied into the GCC manual, in +*note Machine Constraints::, replacing the hand-maintained tables +currently found in that section. Also, in the future the compiler may +use this to give more helpful diagnostics when poor choice of `asm' +constraints causes a reload failure. + + If you put the pseudo-Texinfo directive `@internal' at the beginning +of a docstring, then (in the future) it will appear only in the +internals manual's version of the machine-specific constraint tables. +Use this for constraints that should not appear in `asm' statements. + + +File: gccint.info, Node: C Constraint Interface, Prev: Define Constraints, Up: Constraints + +16.8.8 Testing constraints from C +--------------------------------- + +It is occasionally useful to test a constraint from C code rather than +implicitly via the constraint string in a `match_operand'. The +generated file `tm_p.h' declares a few interfaces for working with +machine-specific constraints. None of these interfaces work with the +generic constraints described in *note Simple Constraints::. This may +change in the future. + + *Warning:* `tm_p.h' may declare other functions that operate on +constraints, besides the ones documented here. Do not use those +functions from machine-dependent code. They exist to implement the old +constraint interface that machine-independent components of the +compiler still expect. They will change or disappear in the future. + + Some valid constraint names are not valid C identifiers, so there is a +mangling scheme for referring to them from C. Constraint names that do +not contain angle brackets or underscores are left unchanged. +Underscores are doubled, each `<' is replaced with `_l', and each `>' +with `_g'. Here are some examples: + + *Original* *Mangled* + `x' `x' + `P42x' `P42x' + `P4_x' `P4__x' + `P4>x' `P4_gx' + `P4>>' `P4_g_g' + `P4_g>' `P4__g_g' + + Throughout this section, the variable C is either a constraint in the +abstract sense, or a constant from `enum constraint_num'; the variable +M is a mangled constraint name (usually as part of a larger identifier). + + -- Enum: constraint_num + For each machine-specific constraint, there is a corresponding + enumeration constant: `CONSTRAINT_' plus the mangled name of the + constraint. Functions that take an `enum constraint_num' as an + argument expect one of these constants. + + Machine-independent constraints do not have associated constants. + This may change in the future. + + -- Function: inline bool satisfies_constraint_M (rtx EXP) + For each machine-specific, non-register constraint M, there is one + of these functions; it returns `true' if EXP satisfies the + constraint. These functions are only visible if `rtl.h' was + included before `tm_p.h'. + + -- Function: bool constraint_satisfied_p (rtx EXP, enum constraint_num + C) + Like the `satisfies_constraint_M' functions, but the constraint to + test is given as an argument, C. If C specifies a register + constraint, this function will always return `false'. + + -- Function: enum reg_class regclass_for_constraint (enum + constraint_num C) + Returns the register class associated with C. If C is not a + register constraint, or those registers are not available for the + currently selected subtarget, returns `NO_REGS'. + + Here is an example use of `satisfies_constraint_M'. In peephole +optimizations (*note Peephole Definitions::), operand constraint +strings are ignored, so if there are relevant constraints, they must be +tested in the C condition. In the example, the optimization is applied +if operand 2 does _not_ satisfy the `K' constraint. (This is a +simplified version of a peephole definition from the i386 machine +description.) + + (define_peephole2 + [(match_scratch:SI 3 "r") + (set (match_operand:SI 0 "register_operand" "") + (mult:SI (match_operand:SI 1 "memory_operand" "") + (match_operand:SI 2 "immediate_operand" "")))] + + "!satisfies_constraint_K (operands[2])" + + [(set (match_dup 3) (match_dup 1)) + (set (match_dup 0) (mult:SI (match_dup 3) (match_dup 2)))] + + "") + + +File: gccint.info, Node: Standard Names, Next: Pattern Ordering, Prev: Constraints, Up: Machine Desc + +16.9 Standard Pattern Names For Generation +========================================== + +Here is a table of the instruction names that are meaningful in the RTL +generation pass of the compiler. Giving one of these names to an +instruction pattern tells the RTL generation pass that it can use the +pattern to accomplish a certain task. + +`movM' + Here M stands for a two-letter machine mode name, in lowercase. + This instruction pattern moves data with that machine mode from + operand 1 to operand 0. For example, `movsi' moves full-word data. + + If operand 0 is a `subreg' with mode M of a register whose own + mode is wider than M, the effect of this instruction is to store + the specified value in the part of the register that corresponds + to mode M. Bits outside of M, but which are within the same + target word as the `subreg' are undefined. Bits which are outside + the target word are left unchanged. + + This class of patterns is special in several ways. First of all, + each of these names up to and including full word size _must_ be + defined, because there is no other way to copy a datum from one + place to another. If there are patterns accepting operands in + larger modes, `movM' must be defined for integer modes of those + sizes. + + Second, these patterns are not used solely in the RTL generation + pass. Even the reload pass can generate move insns to copy values + from stack slots into temporary registers. When it does so, one + of the operands is a hard register and the other is an operand + that can need to be reloaded into a register. + + Therefore, when given such a pair of operands, the pattern must + generate RTL which needs no reloading and needs no temporary + registers--no registers other than the operands. For example, if + you support the pattern with a `define_expand', then in such a + case the `define_expand' mustn't call `force_reg' or any other such + function which might generate new pseudo registers. + + This requirement exists even for subword modes on a RISC machine + where fetching those modes from memory normally requires several + insns and some temporary registers. + + During reload a memory reference with an invalid address may be + passed as an operand. Such an address will be replaced with a + valid address later in the reload pass. In this case, nothing may + be done with the address except to use it as it stands. If it is + copied, it will not be replaced with a valid address. No attempt + should be made to make such an address into a valid address and no + routine (such as `change_address') that will do so may be called. + Note that `general_operand' will fail when applied to such an + address. + + The global variable `reload_in_progress' (which must be explicitly + declared if required) can be used to determine whether such special + handling is required. + + The variety of operands that have reloads depends on the rest of + the machine description, but typically on a RISC machine these can + only be pseudo registers that did not get hard registers, while on + other machines explicit memory references will get optional + reloads. + + If a scratch register is required to move an object to or from + memory, it can be allocated using `gen_reg_rtx' prior to life + analysis. + + If there are cases which need scratch registers during or after + reload, you must provide an appropriate secondary_reload target + hook. + + The macro `can_create_pseudo_p' can be used to determine if it is + unsafe to create new pseudo registers. If this variable is + nonzero, then it is unsafe to call `gen_reg_rtx' to allocate a new + pseudo. + + The constraints on a `movM' must permit moving any hard register + to any other hard register provided that `HARD_REGNO_MODE_OK' + permits mode M in both registers and `TARGET_REGISTER_MOVE_COST' + applied to their classes returns a value of 2. + + It is obligatory to support floating point `movM' instructions + into and out of any registers that can hold fixed point values, + because unions and structures (which have modes `SImode' or + `DImode') can be in those registers and they may have floating + point members. + + There may also be a need to support fixed point `movM' + instructions in and out of floating point registers. + Unfortunately, I have forgotten why this was so, and I don't know + whether it is still true. If `HARD_REGNO_MODE_OK' rejects fixed + point values in floating point registers, then the constraints of + the fixed point `movM' instructions must be designed to avoid ever + trying to reload into a floating point register. + +`reload_inM' +`reload_outM' + These named patterns have been obsoleted by the target hook + `secondary_reload'. + + Like `movM', but used when a scratch register is required to move + between operand 0 and operand 1. Operand 2 describes the scratch + register. See the discussion of the `SECONDARY_RELOAD_CLASS' + macro in *note Register Classes::. + + There are special restrictions on the form of the `match_operand's + used in these patterns. First, only the predicate for the reload + operand is examined, i.e., `reload_in' examines operand 1, but not + the predicates for operand 0 or 2. Second, there may be only one + alternative in the constraints. Third, only a single register + class letter may be used for the constraint; subsequent constraint + letters are ignored. As a special exception, an empty constraint + string matches the `ALL_REGS' register class. This may relieve + ports of the burden of defining an `ALL_REGS' constraint letter + just for these patterns. + +`movstrictM' + Like `movM' except that if operand 0 is a `subreg' with mode M of + a register whose natural mode is wider, the `movstrictM' + instruction is guaranteed not to alter any of the register except + the part which belongs to mode M. + +`movmisalignM' + This variant of a move pattern is designed to load or store a value + from a memory address that is not naturally aligned for its mode. + For a store, the memory will be in operand 0; for a load, the + memory will be in operand 1. The other operand is guaranteed not + to be a memory, so that it's easy to tell whether this is a load + or store. + + This pattern is used by the autovectorizer, and when expanding a + `MISALIGNED_INDIRECT_REF' expression. + +`load_multiple' + Load several consecutive memory locations into consecutive + registers. Operand 0 is the first of the consecutive registers, + operand 1 is the first memory location, and operand 2 is a + constant: the number of consecutive registers. + + Define this only if the target machine really has such an + instruction; do not define this if the most efficient way of + loading consecutive registers from memory is to do them one at a + time. + + On some machines, there are restrictions as to which consecutive + registers can be stored into memory, such as particular starting or + ending register numbers or only a range of valid counts. For those + machines, use a `define_expand' (*note Expander Definitions::) and + make the pattern fail if the restrictions are not met. + + Write the generated insn as a `parallel' with elements being a + `set' of one register from the appropriate memory location (you may + also need `use' or `clobber' elements). Use a `match_parallel' + (*note RTL Template::) to recognize the insn. See `rs6000.md' for + examples of the use of this insn pattern. + +`store_multiple' + Similar to `load_multiple', but store several consecutive registers + into consecutive memory locations. Operand 0 is the first of the + consecutive memory locations, operand 1 is the first register, and + operand 2 is a constant: the number of consecutive registers. + +`vec_setM' + Set given field in the vector value. Operand 0 is the vector to + modify, operand 1 is new value of field and operand 2 specify the + field index. + +`vec_extractM' + Extract given field from the vector value. Operand 1 is the + vector, operand 2 specify field index and operand 0 place to store + value into. + +`vec_extract_evenM' + Extract even elements from the input vectors (operand 1 and + operand 2). The even elements of operand 2 are concatenated to + the even elements of operand 1 in their original order. The result + is stored in operand 0. The output and input vectors should have + the same modes. + +`vec_extract_oddM' + Extract odd elements from the input vectors (operand 1 and operand + 2). The odd elements of operand 2 are concatenated to the odd + elements of operand 1 in their original order. The result is + stored in operand 0. The output and input vectors should have the + same modes. + +`vec_interleave_highM' + Merge high elements of the two input vectors into the output + vector. The output and input vectors should have the same modes + (`N' elements). The high `N/2' elements of the first input vector + are interleaved with the high `N/2' elements of the second input + vector. + +`vec_interleave_lowM' + Merge low elements of the two input vectors into the output + vector. The output and input vectors should have the same modes + (`N' elements). The low `N/2' elements of the first input vector + are interleaved with the low `N/2' elements of the second input + vector. + +`vec_initM' + Initialize the vector to given values. Operand 0 is the vector to + initialize and operand 1 is parallel containing values for + individual fields. + +`pushM1' + Output a push instruction. Operand 0 is value to push. Used only + when `PUSH_ROUNDING' is defined. For historical reason, this + pattern may be missing and in such case an `mov' expander is used + instead, with a `MEM' expression forming the push operation. The + `mov' expander method is deprecated. + +`addM3' + Add operand 2 and operand 1, storing the result in operand 0. All + operands must have mode M. This can be used even on two-address + machines, by means of constraints requiring operands 1 and 0 to be + the same location. + +`ssaddM3', `usaddM3' + +`subM3', `sssubM3', `ussubM3' + +`mulM3', `ssmulM3', `usmulM3' +`divM3', `ssdivM3' +`udivM3', `usdivM3' +`modM3', `umodM3' +`uminM3', `umaxM3' +`andM3', `iorM3', `xorM3' + Similar, for other arithmetic operations. + +`fmaM4' + Multiply operand 2 and operand 1, then add operand 3, storing the + result in operand 0. All operands must have mode M. This pattern + is used to implement the `fma', `fmaf', and `fmal' builtin + functions from the ISO C99 standard. The `fma' operation may + produce different results than doing the multiply followed by the + add if the machine does not perform a rounding step between the + operations. + +`fmsM4' + Like `fmaM4', except operand 3 subtracted from the product instead + of added to the product. This is represented in the rtl as + + (fma:M OP1 OP2 (neg:M OP3)) + +`fnmaM4' + Like `fmaM4' except that the intermediate product is negated + before being added to operand 3. This is represented in the rtl as + + (fma:M (neg:M OP1) OP2 OP3) + +`fnmsM4' + Like `fmsM4' except that the intermediate product is negated + before subtracting operand 3. This is represented in the rtl as + + (fma:M (neg:M OP1) OP2 (neg:M OP3)) + +`sminM3', `smaxM3' + Signed minimum and maximum operations. When used with floating + point, if both operands are zeros, or if either operand is `NaN', + then it is unspecified which of the two operands is returned as + the result. + +`reduc_smin_M', `reduc_smax_M' + Find the signed minimum/maximum of the elements of a vector. The + vector is operand 1, and the scalar result is stored in the least + significant bits of operand 0 (also a vector). The output and + input vector should have the same modes. + +`reduc_umin_M', `reduc_umax_M' + Find the unsigned minimum/maximum of the elements of a vector. The + vector is operand 1, and the scalar result is stored in the least + significant bits of operand 0 (also a vector). The output and + input vector should have the same modes. + +`reduc_splus_M' + Compute the sum of the signed elements of a vector. The vector is + operand 1, and the scalar result is stored in the least + significant bits of operand 0 (also a vector). The output and + input vector should have the same modes. + +`reduc_uplus_M' + Compute the sum of the unsigned elements of a vector. The vector + is operand 1, and the scalar result is stored in the least + significant bits of operand 0 (also a vector). The output and + input vector should have the same modes. + +`sdot_prodM' + +`udot_prodM' + Compute the sum of the products of two signed/unsigned elements. + Operand 1 and operand 2 are of the same mode. Their product, which + is of a wider mode, is computed and added to operand 3. Operand 3 + is of a mode equal or wider than the mode of the product. The + result is placed in operand 0, which is of the same mode as + operand 3. + +`ssum_widenM3' + +`usum_widenM3' + Operands 0 and 2 are of the same mode, which is wider than the + mode of operand 1. Add operand 1 to operand 2 and place the + widened result in operand 0. (This is used express accumulation of + elements into an accumulator of a wider mode.) + +`vec_shl_M', `vec_shr_M' + Whole vector left/right shift in bits. Operand 1 is a vector to + be shifted. Operand 2 is an integer shift amount in bits. + Operand 0 is where the resulting shifted vector is stored. The + output and input vectors should have the same modes. + +`vec_pack_trunc_M' + Narrow (demote) and merge the elements of two vectors. Operands 1 + and 2 are vectors of the same mode having N integral or floating + point elements of size S. Operand 0 is the resulting vector in + which 2*N elements of size N/2 are concatenated after narrowing + them down using truncation. + +`vec_pack_ssat_M', `vec_pack_usat_M' + Narrow (demote) and merge the elements of two vectors. Operands 1 + and 2 are vectors of the same mode having N integral elements of + size S. Operand 0 is the resulting vector in which the elements + of the two input vectors are concatenated after narrowing them + down using signed/unsigned saturating arithmetic. + +`vec_pack_sfix_trunc_M', `vec_pack_ufix_trunc_M' + Narrow, convert to signed/unsigned integral type and merge the + elements of two vectors. Operands 1 and 2 are vectors of the same + mode having N floating point elements of size S. Operand 0 is the + resulting vector in which 2*N elements of size N/2 are + concatenated. + +`vec_unpacks_hi_M', `vec_unpacks_lo_M' + Extract and widen (promote) the high/low part of a vector of signed + integral or floating point elements. The input vector (operand 1) + has N elements of size S. Widen (promote) the high/low elements + of the vector using signed or floating point extension and place + the resulting N/2 values of size 2*S in the output vector (operand + 0). + +`vec_unpacku_hi_M', `vec_unpacku_lo_M' + Extract and widen (promote) the high/low part of a vector of + unsigned integral elements. The input vector (operand 1) has N + elements of size S. Widen (promote) the high/low elements of the + vector using zero extension and place the resulting N/2 values of + size 2*S in the output vector (operand 0). + +`vec_unpacks_float_hi_M', `vec_unpacks_float_lo_M' +`vec_unpacku_float_hi_M', `vec_unpacku_float_lo_M' + Extract, convert to floating point type and widen the high/low + part of a vector of signed/unsigned integral elements. The input + vector (operand 1) has N elements of size S. Convert the high/low + elements of the vector using floating point conversion and place + the resulting N/2 values of size 2*S in the output vector (operand + 0). + +`vec_widen_umult_hi_M', `vec_widen_umult_lo_M' +`vec_widen_smult_hi_M', `vec_widen_smult_lo_M' + Signed/Unsigned widening multiplication. The two inputs (operands + 1 and 2) are vectors with N signed/unsigned elements of size S. + Multiply the high/low elements of the two vectors, and put the N/2 + products of size 2*S in the output vector (operand 0). + +`mulhisi3' + Multiply operands 1 and 2, which have mode `HImode', and store a + `SImode' product in operand 0. + +`mulqihi3', `mulsidi3' + Similar widening-multiplication instructions of other widths. + +`umulqihi3', `umulhisi3', `umulsidi3' + Similar widening-multiplication instructions that do unsigned + multiplication. + +`usmulqihi3', `usmulhisi3', `usmulsidi3' + Similar widening-multiplication instructions that interpret the + first operand as unsigned and the second operand as signed, then + do a signed multiplication. + +`smulM3_highpart' + Perform a signed multiplication of operands 1 and 2, which have + mode M, and store the most significant half of the product in + operand 0. The least significant half of the product is discarded. + +`umulM3_highpart' + Similar, but the multiplication is unsigned. + +`maddMN4' + Multiply operands 1 and 2, sign-extend them to mode N, add operand + 3, and store the result in operand 0. Operands 1 and 2 have mode + M and operands 0 and 3 have mode N. Both modes must be integer or + fixed-point modes and N must be twice the size of M. + + In other words, `maddMN4' is like `mulMN3' except that it also + adds operand 3. + + These instructions are not allowed to `FAIL'. + +`umaddMN4' + Like `maddMN4', but zero-extend the multiplication operands + instead of sign-extending them. + +`ssmaddMN4' + Like `maddMN4', but all involved operations must be + signed-saturating. + +`usmaddMN4' + Like `umaddMN4', but all involved operations must be + unsigned-saturating. + +`msubMN4' + Multiply operands 1 and 2, sign-extend them to mode N, subtract the + result from operand 3, and store the result in operand 0. + Operands 1 and 2 have mode M and operands 0 and 3 have mode N. + Both modes must be integer or fixed-point modes and N must be twice + the size of M. + + In other words, `msubMN4' is like `mulMN3' except that it also + subtracts the result from operand 3. + + These instructions are not allowed to `FAIL'. + +`umsubMN4' + Like `msubMN4', but zero-extend the multiplication operands + instead of sign-extending them. + +`ssmsubMN4' + Like `msubMN4', but all involved operations must be + signed-saturating. + +`usmsubMN4' + Like `umsubMN4', but all involved operations must be + unsigned-saturating. + +`divmodM4' + Signed division that produces both a quotient and a remainder. + Operand 1 is divided by operand 2 to produce a quotient stored in + operand 0 and a remainder stored in operand 3. + + For machines with an instruction that produces both a quotient and + a remainder, provide a pattern for `divmodM4' but do not provide + patterns for `divM3' and `modM3'. This allows optimization in the + relatively common case when both the quotient and remainder are + computed. + + If an instruction that just produces a quotient or just a remainder + exists and is more efficient than the instruction that produces + both, write the output routine of `divmodM4' to call + `find_reg_note' and look for a `REG_UNUSED' note on the quotient + or remainder and generate the appropriate instruction. + +`udivmodM4' + Similar, but does unsigned division. + +`ashlM3', `ssashlM3', `usashlM3' + Arithmetic-shift operand 1 left by a number of bits specified by + operand 2, and store the result in operand 0. Here M is the mode + of operand 0 and operand 1; operand 2's mode is specified by the + instruction pattern, and the compiler will convert the operand to + that mode before generating the instruction. The meaning of + out-of-range shift counts can optionally be specified by + `TARGET_SHIFT_TRUNCATION_MASK'. *Note + TARGET_SHIFT_TRUNCATION_MASK::. Operand 2 is always a scalar type. + +`ashrM3', `lshrM3', `rotlM3', `rotrM3' + Other shift and rotate instructions, analogous to the `ashlM3' + instructions. Operand 2 is always a scalar type. + +`vashlM3', `vashrM3', `vlshrM3', `vrotlM3', `vrotrM3' + Vector shift and rotate instructions that take vectors as operand 2 + instead of a scalar type. + +`negM2', `ssnegM2', `usnegM2' + Negate operand 1 and store the result in operand 0. + +`absM2' + Store the absolute value of operand 1 into operand 0. + +`sqrtM2' + Store the square root of operand 1 into operand 0. + + The `sqrt' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `sqrtf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`fmodM3' + Store the remainder of dividing operand 1 by operand 2 into + operand 0, rounded towards zero to an integer. + + The `fmod' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `fmodf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`remainderM3' + Store the remainder of dividing operand 1 by operand 2 into + operand 0, rounded to the nearest integer. + + The `remainder' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `remainderf' + built-in function uses the mode which corresponds to the C data + type `float'. + +`cosM2' + Store the cosine of operand 1 into operand 0. + + The `cos' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `cosf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`sinM2' + Store the sine of operand 1 into operand 0. + + The `sin' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `sinf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`expM2' + Store the exponential of operand 1 into operand 0. + + The `exp' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `expf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`logM2' + Store the natural logarithm of operand 1 into operand 0. + + The `log' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `logf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`powM3' + Store the value of operand 1 raised to the exponent operand 2 into + operand 0. + + The `pow' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `powf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`atan2M3' + Store the arc tangent (inverse tangent) of operand 1 divided by + operand 2 into operand 0, using the signs of both arguments to + determine the quadrant of the result. + + The `atan2' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `atan2f' built-in + function uses the mode which corresponds to the C data type + `float'. + +`floorM2' + Store the largest integral value not greater than argument. + + The `floor' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `floorf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`btruncM2' + Store the argument rounded to integer towards zero. + + The `trunc' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `truncf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`roundM2' + Store the argument rounded to integer away from zero. + + The `round' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `roundf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`ceilM2' + Store the argument rounded to integer away from zero. + + The `ceil' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `ceilf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`nearbyintM2' + Store the argument rounded according to the default rounding mode + + The `nearbyint' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `nearbyintf' + built-in function uses the mode which corresponds to the C data + type `float'. + +`rintM2' + Store the argument rounded according to the default rounding mode + and raise the inexact exception when the result differs in value + from the argument + + The `rint' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `rintf' built-in + function uses the mode which corresponds to the C data type + `float'. + +`lrintMN2' + Convert operand 1 (valid for floating point mode M) to fixed point + mode N as a signed number according to the current rounding mode + and store in operand 0 (which has mode N). + +`lroundMN2' + Convert operand 1 (valid for floating point mode M) to fixed point + mode N as a signed number rounding to nearest and away from zero + and store in operand 0 (which has mode N). + +`lfloorMN2' + Convert operand 1 (valid for floating point mode M) to fixed point + mode N as a signed number rounding down and store in operand 0 + (which has mode N). + +`lceilMN2' + Convert operand 1 (valid for floating point mode M) to fixed point + mode N as a signed number rounding up and store in operand 0 + (which has mode N). + +`copysignM3' + Store a value with the magnitude of operand 1 and the sign of + operand 2 into operand 0. + + The `copysign' built-in function of C always uses the mode which + corresponds to the C data type `double' and the `copysignf' + built-in function uses the mode which corresponds to the C data + type `float'. + +`ffsM2' + Store into operand 0 one plus the index of the least significant + 1-bit of operand 1. If operand 1 is zero, store zero. M is the + mode of operand 0; operand 1's mode is specified by the instruction + pattern, and the compiler will convert the operand to that mode + before generating the instruction. + + The `ffs' built-in function of C always uses the mode which + corresponds to the C data type `int'. + +`clzM2' + Store into operand 0 the number of leading 0-bits in X, starting + at the most significant bit position. If X is 0, the + `CLZ_DEFINED_VALUE_AT_ZERO' (*note Misc::) macro defines if the + result is undefined or has a useful value. M is the mode of + operand 0; operand 1's mode is specified by the instruction + pattern, and the compiler will convert the operand to that mode + before generating the instruction. + +`ctzM2' + Store into operand 0 the number of trailing 0-bits in X, starting + at the least significant bit position. If X is 0, the + `CTZ_DEFINED_VALUE_AT_ZERO' (*note Misc::) macro defines if the + result is undefined or has a useful value. M is the mode of + operand 0; operand 1's mode is specified by the instruction + pattern, and the compiler will convert the operand to that mode + before generating the instruction. + +`popcountM2' + Store into operand 0 the number of 1-bits in X. M is the mode of + operand 0; operand 1's mode is specified by the instruction + pattern, and the compiler will convert the operand to that mode + before generating the instruction. + +`parityM2' + Store into operand 0 the parity of X, i.e. the number of 1-bits in + X modulo 2. M is the mode of operand 0; operand 1's mode is + specified by the instruction pattern, and the compiler will convert + the operand to that mode before generating the instruction. + +`one_cmplM2' + Store the bitwise-complement of operand 1 into operand 0. + +`movmemM' + Block move instruction. The destination and source blocks of + memory are the first two operands, and both are `mem:BLK's with an + address in mode `Pmode'. + + The number of bytes to move is the third operand, in mode M. + Usually, you specify `word_mode' for M. However, if you can + generate better code knowing the range of valid lengths is smaller + than those representable in a full word, you should provide a + pattern with a mode corresponding to the range of values you can + handle efficiently (e.g., `QImode' for values in the range 0-127; + note we avoid numbers that appear negative) and also a pattern + with `word_mode'. + + The fourth operand is the known shared alignment of the source and + destination, in the form of a `const_int' rtx. Thus, if the + compiler knows that both source and destination are word-aligned, + it may provide the value 4 for this operand. + + Optional operands 5 and 6 specify expected alignment and size of + block respectively. The expected alignment differs from alignment + in operand 4 in a way that the blocks are not required to be + aligned according to it in all cases. This expected alignment is + also in bytes, just like operand 4. Expected size, when unknown, + is set to `(const_int -1)'. + + Descriptions of multiple `movmemM' patterns can only be beneficial + if the patterns for smaller modes have fewer restrictions on their + first, second and fourth operands. Note that the mode M in + `movmemM' does not impose any restriction on the mode of + individually moved data units in the block. + + These patterns need not give special consideration to the + possibility that the source and destination strings might overlap. + +`movstr' + String copy instruction, with `stpcpy' semantics. Operand 0 is an + output operand in mode `Pmode'. The addresses of the destination + and source strings are operands 1 and 2, and both are `mem:BLK's + with addresses in mode `Pmode'. The execution of the expansion of + this pattern should store in operand 0 the address in which the + `NUL' terminator was stored in the destination string. + +`setmemM' + Block set instruction. The destination string is the first + operand, given as a `mem:BLK' whose address is in mode `Pmode'. + The number of bytes to set is the second operand, in mode M. The + value to initialize the memory with is the third operand. Targets + that only support the clearing of memory should reject any value + that is not the constant 0. See `movmemM' for a discussion of the + choice of mode. + + The fourth operand is the known alignment of the destination, in + the form of a `const_int' rtx. Thus, if the compiler knows that + the destination is word-aligned, it may provide the value 4 for + this operand. + + Optional operands 5 and 6 specify expected alignment and size of + block respectively. The expected alignment differs from alignment + in operand 4 in a way that the blocks are not required to be + aligned according to it in all cases. This expected alignment is + also in bytes, just like operand 4. Expected size, when unknown, + is set to `(const_int -1)'. + + The use for multiple `setmemM' is as for `movmemM'. + +`cmpstrnM' + String compare instruction, with five operands. Operand 0 is the + output; it has mode M. The remaining four operands are like the + operands of `movmemM'. The two memory blocks specified are + compared byte by byte in lexicographic order starting at the + beginning of each string. The instruction is not allowed to + prefetch more than one byte at a time since either string may end + in the first byte and reading past that may access an invalid page + or segment and cause a fault. The comparison terminates early if + the fetched bytes are different or if they are equal to zero. The + effect of the instruction is to store a value in operand 0 whose + sign indicates the result of the comparison. + +`cmpstrM' + String compare instruction, without known maximum length. Operand + 0 is the output; it has mode M. The second and third operand are + the blocks of memory to be compared; both are `mem:BLK' with an + address in mode `Pmode'. + + The fourth operand is the known shared alignment of the source and + destination, in the form of a `const_int' rtx. Thus, if the + compiler knows that both source and destination are word-aligned, + it may provide the value 4 for this operand. + + The two memory blocks specified are compared byte by byte in + lexicographic order starting at the beginning of each string. The + instruction is not allowed to prefetch more than one byte at a + time since either string may end in the first byte and reading + past that may access an invalid page or segment and cause a fault. + The comparison will terminate when the fetched bytes are different + or if they are equal to zero. The effect of the instruction is to + store a value in operand 0 whose sign indicates the result of the + comparison. + +`cmpmemM' + Block compare instruction, with five operands like the operands of + `cmpstrM'. The two memory blocks specified are compared byte by + byte in lexicographic order starting at the beginning of each + block. Unlike `cmpstrM' the instruction can prefetch any bytes in + the two memory blocks. Also unlike `cmpstrM' the comparison will + not stop if both bytes are zero. The effect of the instruction is + to store a value in operand 0 whose sign indicates the result of + the comparison. + +`strlenM' + Compute the length of a string, with three operands. Operand 0 is + the result (of mode M), operand 1 is a `mem' referring to the + first character of the string, operand 2 is the character to + search for (normally zero), and operand 3 is a constant describing + the known alignment of the beginning of the string. + +`floatMN2' + Convert signed integer operand 1 (valid for fixed point mode M) to + floating point mode N and store in operand 0 (which has mode N). + +`floatunsMN2' + Convert unsigned integer operand 1 (valid for fixed point mode M) + to floating point mode N and store in operand 0 (which has mode N). + +`fixMN2' + Convert operand 1 (valid for floating point mode M) to fixed point + mode N as a signed number and store in operand 0 (which has mode + N). This instruction's result is defined only when the value of + operand 1 is an integer. + + If the machine description defines this pattern, it also needs to + define the `ftrunc' pattern. + +`fixunsMN2' + Convert operand 1 (valid for floating point mode M) to fixed point + mode N as an unsigned number and store in operand 0 (which has + mode N). This instruction's result is defined only when the value + of operand 1 is an integer. + +`ftruncM2' + Convert operand 1 (valid for floating point mode M) to an integer + value, still represented in floating point mode M, and store it in + operand 0 (valid for floating point mode M). + +`fix_truncMN2' + Like `fixMN2' but works for any floating point value of mode M by + converting the value to an integer. + +`fixuns_truncMN2' + Like `fixunsMN2' but works for any floating point value of mode M + by converting the value to an integer. + +`truncMN2' + Truncate operand 1 (valid for mode M) to mode N and store in + operand 0 (which has mode N). Both modes must be fixed point or + both floating point. + +`extendMN2' + Sign-extend operand 1 (valid for mode M) to mode N and store in + operand 0 (which has mode N). Both modes must be fixed point or + both floating point. + +`zero_extendMN2' + Zero-extend operand 1 (valid for mode M) to mode N and store in + operand 0 (which has mode N). Both modes must be fixed point. + +`fractMN2' + Convert operand 1 of mode M to mode N and store in operand 0 + (which has mode N). Mode M and mode N could be fixed-point to + fixed-point, signed integer to fixed-point, fixed-point to signed + integer, floating-point to fixed-point, or fixed-point to + floating-point. When overflows or underflows happen, the results + are undefined. + +`satfractMN2' + Convert operand 1 of mode M to mode N and store in operand 0 + (which has mode N). Mode M and mode N could be fixed-point to + fixed-point, signed integer to fixed-point, or floating-point to + fixed-point. When overflows or underflows happen, the instruction + saturates the results to the maximum or the minimum. + +`fractunsMN2' + Convert operand 1 of mode M to mode N and store in operand 0 + (which has mode N). Mode M and mode N could be unsigned integer + to fixed-point, or fixed-point to unsigned integer. When + overflows or underflows happen, the results are undefined. + +`satfractunsMN2' + Convert unsigned integer operand 1 of mode M to fixed-point mode N + and store in operand 0 (which has mode N). When overflows or + underflows happen, the instruction saturates the results to the + maximum or the minimum. + +`extv' + Extract a bit-field from operand 1 (a register or memory operand), + where operand 2 specifies the width in bits and operand 3 the + starting bit, and store it in operand 0. Operand 0 must have mode + `word_mode'. Operand 1 may have mode `byte_mode' or `word_mode'; + often `word_mode' is allowed only for registers. Operands 2 and 3 + must be valid for `word_mode'. + + The RTL generation pass generates this instruction only with + constants for operands 2 and 3 and the constant is never zero for + operand 2. + + The bit-field value is sign-extended to a full word integer before + it is stored in operand 0. + +`extzv' + Like `extv' except that the bit-field value is zero-extended. + +`insv' + Store operand 3 (which must be valid for `word_mode') into a + bit-field in operand 0, where operand 1 specifies the width in + bits and operand 2 the starting bit. Operand 0 may have mode + `byte_mode' or `word_mode'; often `word_mode' is allowed only for + registers. Operands 1 and 2 must be valid for `word_mode'. + + The RTL generation pass generates this instruction only with + constants for operands 1 and 2 and the constant is never zero for + operand 1. + +`movMODEcc' + Conditionally move operand 2 or operand 3 into operand 0 according + to the comparison in operand 1. If the comparison is true, + operand 2 is moved into operand 0, otherwise operand 3 is moved. + + The mode of the operands being compared need not be the same as + the operands being moved. Some machines, sparc64 for example, + have instructions that conditionally move an integer value based + on the floating point condition codes and vice versa. + + If the machine does not have conditional move instructions, do not + define these patterns. + +`addMODEcc' + Similar to `movMODEcc' but for conditional addition. Conditionally + move operand 2 or (operands 2 + operand 3) into operand 0 + according to the comparison in operand 1. If the comparison is + true, operand 2 is moved into operand 0, otherwise (operand 2 + + operand 3) is moved. + +`cstoreMODE4' + Store zero or nonzero in operand 0 according to whether a + comparison is true. Operand 1 is a comparison operator. Operand + 2 and operand 3 are the first and second operand of the + comparison, respectively. You specify the mode that operand 0 + must have when you write the `match_operand' expression. The + compiler automatically sees which mode you have used and supplies + an operand of that mode. + + The value stored for a true condition must have 1 as its low bit, + or else must be negative. Otherwise the instruction is not + suitable and you should omit it from the machine description. You + describe to the compiler exactly which value is stored by defining + the macro `STORE_FLAG_VALUE' (*note Misc::). If a description + cannot be found that can be used for all the possible comparison + operators, you should pick one and use a `define_expand' to map + all results onto the one you chose. + + These operations may `FAIL', but should do so only in relatively + uncommon cases; if they would `FAIL' for common cases involving + integer comparisons, it is best to restrict the predicates to not + allow these operands. Likewise if a given comparison operator will + always fail, independent of the operands (for floating-point + modes, the `ordered_comparison_operator' predicate is often useful + in this case). + + If this pattern is omitted, the compiler will generate a + conditional branch--for example, it may copy a constant one to the + target and branching around an assignment of zero to the + target--or a libcall. If the predicate for operand 1 only rejects + some operators, it will also try reordering the operands and/or + inverting the result value (e.g. by an exclusive OR). These + possibilities could be cheaper or equivalent to the instructions + used for the `cstoreMODE4' pattern followed by those required to + convert a positive result from `STORE_FLAG_VALUE' to 1; in this + case, you can and should make operand 1's predicate reject some + operators in the `cstoreMODE4' pattern, or remove the pattern + altogether from the machine description. + +`cbranchMODE4' + Conditional branch instruction combined with a compare instruction. + Operand 0 is a comparison operator. Operand 1 and operand 2 are + the first and second operands of the comparison, respectively. + Operand 3 is a `label_ref' that refers to the label to jump to. + +`jump' + A jump inside a function; an unconditional branch. Operand 0 is + the `label_ref' of the label to jump to. This pattern name is + mandatory on all machines. + +`call' + Subroutine call instruction returning no value. Operand 0 is the + function to call; operand 1 is the number of bytes of arguments + pushed as a `const_int'; operand 2 is the number of registers used + as operands. + + On most machines, operand 2 is not actually stored into the RTL + pattern. It is supplied for the sake of some RISC machines which + need to put this information into the assembler code; they can put + it in the RTL instead of operand 1. + + Operand 0 should be a `mem' RTX whose address is the address of the + function. Note, however, that this address can be a `symbol_ref' + expression even if it would not be a legitimate memory address on + the target machine. If it is also not a valid argument for a call + instruction, the pattern for this operation should be a + `define_expand' (*note Expander Definitions::) that places the + address into a register and uses that register in the call + instruction. + +`call_value' + Subroutine call instruction returning a value. Operand 0 is the + hard register in which the value is returned. There are three more + operands, the same as the three operands of the `call' instruction + (but with numbers increased by one). + + Subroutines that return `BLKmode' objects use the `call' insn. + +`call_pop', `call_value_pop' + Similar to `call' and `call_value', except used if defined and if + `RETURN_POPS_ARGS' is nonzero. They should emit a `parallel' that + contains both the function call and a `set' to indicate the + adjustment made to the frame pointer. + + For machines where `RETURN_POPS_ARGS' can be nonzero, the use of + these patterns increases the number of functions for which the + frame pointer can be eliminated, if desired. + +`untyped_call' + Subroutine call instruction returning a value of any type. + Operand 0 is the function to call; operand 1 is a memory location + where the result of calling the function is to be stored; operand + 2 is a `parallel' expression where each element is a `set' + expression that indicates the saving of a function return value + into the result block. + + This instruction pattern should be defined to support + `__builtin_apply' on machines where special instructions are needed + to call a subroutine with arbitrary arguments or to save the value + returned. This instruction pattern is required on machines that + have multiple registers that can hold a return value (i.e. + `FUNCTION_VALUE_REGNO_P' is true for more than one register). + +`return' + Subroutine return instruction. This instruction pattern name + should be defined only if a single instruction can do all the work + of returning from a function. + + Like the `movM' patterns, this pattern is also used after the RTL + generation phase. In this case it is to support machines where + multiple instructions are usually needed to return from a + function, but some class of functions only requires one + instruction to implement a return. Normally, the applicable + functions are those which do not need to save any registers or + allocate stack space. + + For such machines, the condition specified in this pattern should + only be true when `reload_completed' is nonzero and the function's + epilogue would only be a single instruction. For machines with + register windows, the routine `leaf_function_p' may be used to + determine if a register window push is required. + + Machines that have conditional return instructions should define + patterns such as + + (define_insn "" + [(set (pc) + (if_then_else (match_operator + 0 "comparison_operator" + [(cc0) (const_int 0)]) + (return) + (pc)))] + "CONDITION" + "...") + + where CONDITION would normally be the same condition specified on + the named `return' pattern. + +`untyped_return' + Untyped subroutine return instruction. This instruction pattern + should be defined to support `__builtin_return' on machines where + special instructions are needed to return a value of any type. + + Operand 0 is a memory location where the result of calling a + function with `__builtin_apply' is stored; operand 1 is a + `parallel' expression where each element is a `set' expression + that indicates the restoring of a function return value from the + result block. + +`nop' + No-op instruction. This instruction pattern name should always be + defined to output a no-op in assembler code. `(const_int 0)' will + do as an RTL pattern. + +`indirect_jump' + An instruction to jump to an address which is operand zero. This + pattern name is mandatory on all machines. + +`casesi' + Instruction to jump through a dispatch table, including bounds + checking. This instruction takes five operands: + + 1. The index to dispatch on, which has mode `SImode'. + + 2. The lower bound for indices in the table, an integer constant. + + 3. The total range of indices in the table--the largest index + minus the smallest one (both inclusive). + + 4. A label that precedes the table itself. + + 5. A label to jump to if the index has a value outside the + bounds. + + The table is an `addr_vec' or `addr_diff_vec' inside of a + `jump_insn'. The number of elements in the table is one plus the + difference between the upper bound and the lower bound. + +`tablejump' + Instruction to jump to a variable address. This is a low-level + capability which can be used to implement a dispatch table when + there is no `casesi' pattern. + + This pattern requires two operands: the address or offset, and a + label which should immediately precede the jump table. If the + macro `CASE_VECTOR_PC_RELATIVE' evaluates to a nonzero value then + the first operand is an offset which counts from the address of + the table; otherwise, it is an absolute address to jump to. In + either case, the first operand has mode `Pmode'. + + The `tablejump' insn is always the last insn before the jump table + it uses. Its assembler code normally has no need to use the + second operand, but you should incorporate it in the RTL pattern so + that the jump optimizer will not delete the table as unreachable + code. + +`decrement_and_branch_until_zero' + Conditional branch instruction that decrements a register and + jumps if the register is nonzero. Operand 0 is the register to + decrement and test; operand 1 is the label to jump to if the + register is nonzero. *Note Looping Patterns::. + + This optional instruction pattern is only used by the combiner, + typically for loops reversed by the loop optimizer when strength + reduction is enabled. + +`doloop_end' + Conditional branch instruction that decrements a register and + jumps if the register is nonzero. This instruction takes five + operands: Operand 0 is the register to decrement and test; operand + 1 is the number of loop iterations as a `const_int' or + `const0_rtx' if this cannot be determined until run-time; operand + 2 is the actual or estimated maximum number of iterations as a + `const_int'; operand 3 is the number of enclosed loops as a + `const_int' (an innermost loop has a value of 1); operand 4 is the + label to jump to if the register is nonzero. *Note Looping + Patterns::. + + This optional instruction pattern should be defined for machines + with low-overhead looping instructions as the loop optimizer will + try to modify suitable loops to utilize it. If nested + low-overhead looping is not supported, use a `define_expand' + (*note Expander Definitions::) and make the pattern fail if + operand 3 is not `const1_rtx'. Similarly, if the actual or + estimated maximum number of iterations is too large for this + instruction, make it fail. + +`doloop_begin' + Companion instruction to `doloop_end' required for machines that + need to perform some initialization, such as loading special + registers used by a low-overhead looping instruction. If + initialization insns do not always need to be emitted, use a + `define_expand' (*note Expander Definitions::) and make it fail. + +`canonicalize_funcptr_for_compare' + Canonicalize the function pointer in operand 1 and store the result + into operand 0. + + Operand 0 is always a `reg' and has mode `Pmode'; operand 1 may be + a `reg', `mem', `symbol_ref', `const_int', etc and also has mode + `Pmode'. + + Canonicalization of a function pointer usually involves computing + the address of the function which would be called if the function + pointer were used in an indirect call. + + Only define this pattern if function pointers on the target machine + can have different values but still call the same function when + used in an indirect call. + +`save_stack_block' +`save_stack_function' +`save_stack_nonlocal' +`restore_stack_block' +`restore_stack_function' +`restore_stack_nonlocal' + Most machines save and restore the stack pointer by copying it to + or from an object of mode `Pmode'. Do not define these patterns on + such machines. + + Some machines require special handling for stack pointer saves and + restores. On those machines, define the patterns corresponding to + the non-standard cases by using a `define_expand' (*note Expander + Definitions::) that produces the required insns. The three types + of saves and restores are: + + 1. `save_stack_block' saves the stack pointer at the start of a + block that allocates a variable-sized object, and + `restore_stack_block' restores the stack pointer when the + block is exited. + + 2. `save_stack_function' and `restore_stack_function' do a + similar job for the outermost block of a function and are + used when the function allocates variable-sized objects or + calls `alloca'. Only the epilogue uses the restored stack + pointer, allowing a simpler save or restore sequence on some + machines. + + 3. `save_stack_nonlocal' is used in functions that contain labels + branched to by nested functions. It saves the stack pointer + in such a way that the inner function can use + `restore_stack_nonlocal' to restore the stack pointer. The + compiler generates code to restore the frame and argument + pointer registers, but some machines require saving and + restoring additional data such as register window information + or stack backchains. Place insns in these patterns to save + and restore any such required data. + + When saving the stack pointer, operand 0 is the save area and + operand 1 is the stack pointer. The mode used to allocate the + save area defaults to `Pmode' but you can override that choice by + defining the `STACK_SAVEAREA_MODE' macro (*note Storage Layout::). + You must specify an integral mode, or `VOIDmode' if no save area + is needed for a particular type of save (either because no save is + needed or because a machine-specific save area can be used). + Operand 0 is the stack pointer and operand 1 is the save area for + restore operations. If `save_stack_block' is defined, operand 0 + must not be `VOIDmode' since these saves can be arbitrarily nested. + + A save area is a `mem' that is at a constant offset from + `virtual_stack_vars_rtx' when the stack pointer is saved for use by + nonlocal gotos and a `reg' in the other two cases. + +`allocate_stack' + Subtract (or add if `STACK_GROWS_DOWNWARD' is undefined) operand 1 + from the stack pointer to create space for dynamically allocated + data. + + Store the resultant pointer to this space into operand 0. If you + are allocating space from the main stack, do this by emitting a + move insn to copy `virtual_stack_dynamic_rtx' to operand 0. If + you are allocating the space elsewhere, generate code to copy the + location of the space to operand 0. In the latter case, you must + ensure this space gets freed when the corresponding space on the + main stack is free. + + Do not define this pattern if all that must be done is the + subtraction. Some machines require other operations such as stack + probes or maintaining the back chain. Define this pattern to emit + those operations in addition to updating the stack pointer. + +`check_stack' + If stack checking (*note Stack Checking::) cannot be done on your + system by probing the stack, define this pattern to perform the + needed check and signal an error if the stack has overflowed. The + single operand is the address in the stack farthest from the + current stack pointer that you need to validate. Normally, on + platforms where this pattern is needed, you would obtain the stack + limit from a global or thread-specific variable or register. + +`probe_stack' + If stack checking (*note Stack Checking::) can be done on your + system by probing the stack but doing it with a "store zero" + instruction is not valid or optimal, define this pattern to do the + probing differently and signal an error if the stack has + overflowed. The single operand is the memory reference in the + stack that needs to be probed. + +`nonlocal_goto' + Emit code to generate a non-local goto, e.g., a jump from one + function to a label in an outer function. This pattern has four + arguments, each representing a value to be used in the jump. The + first argument is to be loaded into the frame pointer, the second + is the address to branch to (code to dispatch to the actual label), + the third is the address of a location where the stack is saved, + and the last is the address of the label, to be placed in the + location for the incoming static chain. + + On most machines you need not define this pattern, since GCC will + already generate the correct code, which is to load the frame + pointer and static chain, restore the stack (using the + `restore_stack_nonlocal' pattern, if defined), and jump indirectly + to the dispatcher. You need only define this pattern if this code + will not work on your machine. + +`nonlocal_goto_receiver' + This pattern, if defined, contains code needed at the target of a + nonlocal goto after the code already generated by GCC. You will + not normally need to define this pattern. A typical reason why + you might need this pattern is if some value, such as a pointer to + a global table, must be restored when the frame pointer is + restored. Note that a nonlocal goto only occurs within a + unit-of-translation, so a global table pointer that is shared by + all functions of a given module need not be restored. There are + no arguments. + +`exception_receiver' + This pattern, if defined, contains code needed at the site of an + exception handler that isn't needed at the site of a nonlocal + goto. You will not normally need to define this pattern. A + typical reason why you might need this pattern is if some value, + such as a pointer to a global table, must be restored after + control flow is branched to the handler of an exception. There + are no arguments. + +`builtin_setjmp_setup' + This pattern, if defined, contains additional code needed to + initialize the `jmp_buf'. You will not normally need to define + this pattern. A typical reason why you might need this pattern is + if some value, such as a pointer to a global table, must be + restored. Though it is preferred that the pointer value be + recalculated if possible (given the address of a label for + instance). The single argument is a pointer to the `jmp_buf'. + Note that the buffer is five words long and that the first three + are normally used by the generic mechanism. + +`builtin_setjmp_receiver' + This pattern, if defined, contains code needed at the site of a + built-in setjmp that isn't needed at the site of a nonlocal goto. + You will not normally need to define this pattern. A typical + reason why you might need this pattern is if some value, such as a + pointer to a global table, must be restored. It takes one + argument, which is the label to which builtin_longjmp transfered + control; this pattern may be emitted at a small offset from that + label. + +`builtin_longjmp' + This pattern, if defined, performs the entire action of the + longjmp. You will not normally need to define this pattern unless + you also define `builtin_setjmp_setup'. The single argument is a + pointer to the `jmp_buf'. + +`eh_return' + This pattern, if defined, affects the way `__builtin_eh_return', + and thence the call frame exception handling library routines, are + built. It is intended to handle non-trivial actions needed along + the abnormal return path. + + The address of the exception handler to which the function should + return is passed as operand to this pattern. It will normally + need to copied by the pattern to some special register or memory + location. If the pattern needs to determine the location of the + target call frame in order to do so, it may use + `EH_RETURN_STACKADJ_RTX', if defined; it will have already been + assigned. + + If this pattern is not defined, the default action will be to + simply copy the return address to `EH_RETURN_HANDLER_RTX'. Either + that macro or this pattern needs to be defined if call frame + exception handling is to be used. + +`prologue' + This pattern, if defined, emits RTL for entry to a function. The + function entry is responsible for setting up the stack frame, + initializing the frame pointer register, saving callee saved + registers, etc. + + Using a prologue pattern is generally preferred over defining + `TARGET_ASM_FUNCTION_PROLOGUE' to emit assembly code for the + prologue. + + The `prologue' pattern is particularly useful for targets which + perform instruction scheduling. + +`epilogue' + This pattern emits RTL for exit from a function. The function + exit is responsible for deallocating the stack frame, restoring + callee saved registers and emitting the return instruction. + + Using an epilogue pattern is generally preferred over defining + `TARGET_ASM_FUNCTION_EPILOGUE' to emit assembly code for the + epilogue. + + The `epilogue' pattern is particularly useful for targets which + perform instruction scheduling or which have delay slots for their + return instruction. + +`sibcall_epilogue' + This pattern, if defined, emits RTL for exit from a function + without the final branch back to the calling function. This + pattern will be emitted before any sibling call (aka tail call) + sites. + + The `sibcall_epilogue' pattern must not clobber any arguments used + for parameter passing or any stack slots for arguments passed to + the current function. + +`trap' + This pattern, if defined, signals an error, typically by causing + some kind of signal to be raised. Among other places, it is used + by the Java front end to signal `invalid array index' exceptions. + +`ctrapMM4' + Conditional trap instruction. Operand 0 is a piece of RTL which + performs a comparison, and operands 1 and 2 are the arms of the + comparison. Operand 3 is the trap code, an integer. + + A typical `ctrap' pattern looks like + + (define_insn "ctrapsi4" + [(trap_if (match_operator 0 "trap_operator" + [(match_operand 1 "register_operand") + (match_operand 2 "immediate_operand")]) + (match_operand 3 "const_int_operand" "i"))] + "" + "...") + +`prefetch' + This pattern, if defined, emits code for a non-faulting data + prefetch instruction. Operand 0 is the address of the memory to + prefetch. Operand 1 is a constant 1 if the prefetch is preparing + for a write to the memory address, or a constant 0 otherwise. + Operand 2 is the expected degree of temporal locality of the data + and is a value between 0 and 3, inclusive; 0 means that the data + has no temporal locality, so it need not be left in the cache + after the access; 3 means that the data has a high degree of + temporal locality and should be left in all levels of cache + possible; 1 and 2 mean, respectively, a low or moderate degree of + temporal locality. + + Targets that do not support write prefetches or locality hints can + ignore the values of operands 1 and 2. + +`blockage' + This pattern defines a pseudo insn that prevents the instruction + scheduler from moving instructions across the boundary defined by + the blockage insn. Normally an UNSPEC_VOLATILE pattern. + +`memory_barrier' + If the target memory model is not fully synchronous, then this + pattern should be defined to an instruction that orders both loads + and stores before the instruction with respect to loads and stores + after the instruction. This pattern has no operands. + +`sync_compare_and_swapMODE' + This pattern, if defined, emits code for an atomic compare-and-swap + operation. Operand 1 is the memory on which the atomic operation + is performed. Operand 2 is the "old" value to be compared against + the current contents of the memory location. Operand 3 is the + "new" value to store in the memory if the compare succeeds. + Operand 0 is the result of the operation; it should contain the + contents of the memory before the operation. If the compare + succeeds, this should obviously be a copy of operand 2. + + This pattern must show that both operand 0 and operand 1 are + modified. + + This pattern must issue any memory barrier instructions such that + all memory operations before the atomic operation occur before the + atomic operation and all memory operations after the atomic + operation occur after the atomic operation. + + For targets where the success or failure of the compare-and-swap + operation is available via the status flags, it is possible to + avoid a separate compare operation and issue the subsequent branch + or store-flag operation immediately after the compare-and-swap. + To this end, GCC will look for a `MODE_CC' set in the output of + `sync_compare_and_swapMODE'; if the machine description includes + such a set, the target should also define special `cbranchcc4' + and/or `cstorecc4' instructions. GCC will then be able to take + the destination of the `MODE_CC' set and pass it to the + `cbranchcc4' or `cstorecc4' pattern as the first operand of the + comparison (the second will be `(const_int 0)'). + +`sync_addMODE', `sync_subMODE' +`sync_iorMODE', `sync_andMODE' +`sync_xorMODE', `sync_nandMODE' + These patterns emit code for an atomic operation on memory. + Operand 0 is the memory on which the atomic operation is performed. + Operand 1 is the second operand to the binary operator. + + This pattern must issue any memory barrier instructions such that + all memory operations before the atomic operation occur before the + atomic operation and all memory operations after the atomic + operation occur after the atomic operation. + + If these patterns are not defined, the operation will be + constructed from a compare-and-swap operation, if defined. + +`sync_old_addMODE', `sync_old_subMODE' +`sync_old_iorMODE', `sync_old_andMODE' +`sync_old_xorMODE', `sync_old_nandMODE' + These patterns are emit code for an atomic operation on memory, + and return the value that the memory contained before the + operation. Operand 0 is the result value, operand 1 is the memory + on which the atomic operation is performed, and operand 2 is the + second operand to the binary operator. + + This pattern must issue any memory barrier instructions such that + all memory operations before the atomic operation occur before the + atomic operation and all memory operations after the atomic + operation occur after the atomic operation. + + If these patterns are not defined, the operation will be + constructed from a compare-and-swap operation, if defined. + +`sync_new_addMODE', `sync_new_subMODE' +`sync_new_iorMODE', `sync_new_andMODE' +`sync_new_xorMODE', `sync_new_nandMODE' + These patterns are like their `sync_old_OP' counterparts, except + that they return the value that exists in the memory location + after the operation, rather than before the operation. + +`sync_lock_test_and_setMODE' + This pattern takes two forms, based on the capabilities of the + target. In either case, operand 0 is the result of the operand, + operand 1 is the memory on which the atomic operation is + performed, and operand 2 is the value to set in the lock. + + In the ideal case, this operation is an atomic exchange operation, + in which the previous value in memory operand is copied into the + result operand, and the value operand is stored in the memory + operand. + + For less capable targets, any value operand that is not the + constant 1 should be rejected with `FAIL'. In this case the + target may use an atomic test-and-set bit operation. The result + operand should contain 1 if the bit was previously set and 0 if + the bit was previously clear. The true contents of the memory + operand are implementation defined. + + This pattern must issue any memory barrier instructions such that + the pattern as a whole acts as an acquire barrier, that is all + memory operations after the pattern do not occur until the lock is + acquired. + + If this pattern is not defined, the operation will be constructed + from a compare-and-swap operation, if defined. + +`sync_lock_releaseMODE' + This pattern, if defined, releases a lock set by + `sync_lock_test_and_setMODE'. Operand 0 is the memory that + contains the lock; operand 1 is the value to store in the lock. + + If the target doesn't implement full semantics for + `sync_lock_test_and_setMODE', any value operand which is not the + constant 0 should be rejected with `FAIL', and the true contents + of the memory operand are implementation defined. + + This pattern must issue any memory barrier instructions such that + the pattern as a whole acts as a release barrier, that is the lock + is released only after all previous memory operations have + completed. + + If this pattern is not defined, then a `memory_barrier' pattern + will be emitted, followed by a store of the value to the memory + operand. + +`stack_protect_set' + This pattern, if defined, moves a `ptr_mode' value from the memory + in operand 1 to the memory in operand 0 without leaving the value + in a register afterward. This is to avoid leaking the value some + place that an attacker might use to rewrite the stack guard slot + after having clobbered it. + + If this pattern is not defined, then a plain move pattern is + generated. + +`stack_protect_test' + This pattern, if defined, compares a `ptr_mode' value from the + memory in operand 1 with the memory in operand 0 without leaving + the value in a register afterward and branches to operand 2 if the + values weren't equal. + + If this pattern is not defined, then a plain compare pattern and + conditional branch pattern is used. + +`clear_cache' + This pattern, if defined, flushes the instruction cache for a + region of memory. The region is bounded to by the Pmode pointers + in operand 0 inclusive and operand 1 exclusive. + + If this pattern is not defined, a call to the library function + `__clear_cache' is used. + + + +File: gccint.info, Node: Pattern Ordering, Next: Dependent Patterns, Prev: Standard Names, Up: Machine Desc + +16.10 When the Order of Patterns Matters +======================================== + +Sometimes an insn can match more than one instruction pattern. Then the +pattern that appears first in the machine description is the one used. +Therefore, more specific patterns (patterns that will match fewer +things) and faster instructions (those that will produce better code +when they do match) should usually go first in the description. + + In some cases the effect of ordering the patterns can be used to hide +a pattern when it is not valid. For example, the 68000 has an +instruction for converting a fullword to floating point and another for +converting a byte to floating point. An instruction converting an +integer to floating point could match either one. We put the pattern +to convert the fullword first to make sure that one will be used rather +than the other. (Otherwise a large integer might be generated as a +single-byte immediate quantity, which would not work.) Instead of +using this pattern ordering it would be possible to make the pattern +for convert-a-byte smart enough to deal properly with any constant +value. + + +File: gccint.info, Node: Dependent Patterns, Next: Jump Patterns, Prev: Pattern Ordering, Up: Machine Desc + +16.11 Interdependence of Patterns +================================= + +In some cases machines support instructions identical except for the +machine mode of one or more operands. For example, there may be +"sign-extend halfword" and "sign-extend byte" instructions whose +patterns are + + (set (match_operand:SI 0 ...) + (extend:SI (match_operand:HI 1 ...))) + + (set (match_operand:SI 0 ...) + (extend:SI (match_operand:QI 1 ...))) + +Constant integers do not specify a machine mode, so an instruction to +extend a constant value could match either pattern. The pattern it +actually will match is the one that appears first in the file. For +correct results, this must be the one for the widest possible mode +(`HImode', here). If the pattern matches the `QImode' instruction, the +results will be incorrect if the constant value does not actually fit +that mode. + + Such instructions to extend constants are rarely generated because +they are optimized away, but they do occasionally happen in nonoptimized +compilations. + + If a constraint in a pattern allows a constant, the reload pass may +replace a register with a constant permitted by the constraint in some +cases. Similarly for memory references. Because of this substitution, +you should not provide separate patterns for increment and decrement +instructions. Instead, they should be generated from the same pattern +that supports register-register add insns by examining the operands and +generating the appropriate machine instruction. + + +File: gccint.info, Node: Jump Patterns, Next: Looping Patterns, Prev: Dependent Patterns, Up: Machine Desc + +16.12 Defining Jump Instruction Patterns +======================================== + +GCC does not assume anything about how the machine realizes jumps. The +machine description should define a single pattern, usually a +`define_expand', which expands to all the required insns. + + Usually, this would be a comparison insn to set the condition code and +a separate branch insn testing the condition code and branching or not +according to its value. For many machines, however, separating +compares and branches is limiting, which is why the more flexible +approach with one `define_expand' is used in GCC. The machine +description becomes clearer for architectures that have +compare-and-branch instructions but no condition code. It also works +better when different sets of comparison operators are supported by +different kinds of conditional branches (e.g. integer vs. +floating-point), or by conditional branches with respect to conditional +stores. + + Two separate insns are always used if the machine description +represents a condition code register using the legacy RTL expression +`(cc0)', and on most machines that use a separate condition code +register (*note Condition Code::). For machines that use `(cc0)', in +fact, the set and use of the condition code must be separate and +adjacent(1), thus allowing flags in `cc_status' to be used (*note +Condition Code::) and so that the comparison and branch insns could be +located from each other by using the functions `prev_cc0_setter' and +`next_cc0_user'. + + Even in this case having a single entry point for conditional branches +is advantageous, because it handles equally well the case where a single +comparison instruction records the results of both signed and unsigned +comparison of the given operands (with the branch insns coming in +distinct signed and unsigned flavors) as in the x86 or SPARC, and the +case where there are distinct signed and unsigned compare instructions +and only one set of conditional branch instructions as in the PowerPC. + + ---------- Footnotes ---------- + + (1) `note' insns can separate them, though. + + +File: gccint.info, Node: Looping Patterns, Next: Insn Canonicalizations, Prev: Jump Patterns, Up: Machine Desc + +16.13 Defining Looping Instruction Patterns +=========================================== + +Some machines have special jump instructions that can be utilized to +make loops more efficient. A common example is the 68000 `dbra' +instruction which performs a decrement of a register and a branch if the +result was greater than zero. Other machines, in particular digital +signal processors (DSPs), have special block repeat instructions to +provide low-overhead loop support. For example, the TI TMS320C3x/C4x +DSPs have a block repeat instruction that loads special registers to +mark the top and end of a loop and to count the number of loop +iterations. This avoids the need for fetching and executing a +`dbra'-like instruction and avoids pipeline stalls associated with the +jump. + + GCC has three special named patterns to support low overhead looping. +They are `decrement_and_branch_until_zero', `doloop_begin', and +`doloop_end'. The first pattern, `decrement_and_branch_until_zero', is +not emitted during RTL generation but may be emitted during the +instruction combination phase. This requires the assistance of the +loop optimizer, using information collected during strength reduction, +to reverse a loop to count down to zero. Some targets also require the +loop optimizer to add a `REG_NONNEG' note to indicate that the +iteration count is always positive. This is needed if the target +performs a signed loop termination test. For example, the 68000 uses a +pattern similar to the following for its `dbra' instruction: + + (define_insn "decrement_and_branch_until_zero" + [(set (pc) + (if_then_else + (ge (plus:SI (match_operand:SI 0 "general_operand" "+d*am") + (const_int -1)) + (const_int 0)) + (label_ref (match_operand 1 "" "")) + (pc))) + (set (match_dup 0) + (plus:SI (match_dup 0) + (const_int -1)))] + "find_reg_note (insn, REG_NONNEG, 0)" + "...") + + Note that since the insn is both a jump insn and has an output, it must +deal with its own reloads, hence the `m' constraints. Also note that +since this insn is generated by the instruction combination phase +combining two sequential insns together into an implicit parallel insn, +the iteration counter needs to be biased by the same amount as the +decrement operation, in this case -1. Note that the following similar +pattern will not be matched by the combiner. + + (define_insn "decrement_and_branch_until_zero" + [(set (pc) + (if_then_else + (ge (match_operand:SI 0 "general_operand" "+d*am") + (const_int 1)) + (label_ref (match_operand 1 "" "")) + (pc))) + (set (match_dup 0) + (plus:SI (match_dup 0) + (const_int -1)))] + "find_reg_note (insn, REG_NONNEG, 0)" + "...") + + The other two special looping patterns, `doloop_begin' and +`doloop_end', are emitted by the loop optimizer for certain +well-behaved loops with a finite number of loop iterations using +information collected during strength reduction. + + The `doloop_end' pattern describes the actual looping instruction (or +the implicit looping operation) and the `doloop_begin' pattern is an +optional companion pattern that can be used for initialization needed +for some low-overhead looping instructions. + + Note that some machines require the actual looping instruction to be +emitted at the top of the loop (e.g., the TMS320C3x/C4x DSPs). Emitting +the true RTL for a looping instruction at the top of the loop can cause +problems with flow analysis. So instead, a dummy `doloop' insn is +emitted at the end of the loop. The machine dependent reorg pass checks +for the presence of this `doloop' insn and then searches back to the +top of the loop, where it inserts the true looping insn (provided there +are no instructions in the loop which would cause problems). Any +additional labels can be emitted at this point. In addition, if the +desired special iteration counter register was not allocated, this +machine dependent reorg pass could emit a traditional compare and jump +instruction pair. + + The essential difference between the `decrement_and_branch_until_zero' +and the `doloop_end' patterns is that the loop optimizer allocates an +additional pseudo register for the latter as an iteration counter. +This pseudo register cannot be used within the loop (i.e., general +induction variables cannot be derived from it), however, in many cases +the loop induction variable may become redundant and removed by the +flow pass. + + +File: gccint.info, Node: Insn Canonicalizations, Next: Expander Definitions, Prev: Looping Patterns, Up: Machine Desc + +16.14 Canonicalization of Instructions +====================================== + +There are often cases where multiple RTL expressions could represent an +operation performed by a single machine instruction. This situation is +most commonly encountered with logical, branch, and multiply-accumulate +instructions. In such cases, the compiler attempts to convert these +multiple RTL expressions into a single canonical form to reduce the +number of insn patterns required. + + In addition to algebraic simplifications, following canonicalizations +are performed: + + * For commutative and comparison operators, a constant is always + made the second operand. If a machine only supports a constant as + the second operand, only patterns that match a constant in the + second operand need be supplied. + + * For associative operators, a sequence of operators will always + chain to the left; for instance, only the left operand of an + integer `plus' can itself be a `plus'. `and', `ior', `xor', + `plus', `mult', `smin', `smax', `umin', and `umax' are associative + when applied to integers, and sometimes to floating-point. + + * For these operators, if only one operand is a `neg', `not', + `mult', `plus', or `minus' expression, it will be the first + operand. + + * In combinations of `neg', `mult', `plus', and `minus', the `neg' + operations (if any) will be moved inside the operations as far as + possible. For instance, `(neg (mult A B))' is canonicalized as + `(mult (neg A) B)', but `(plus (mult (neg B) C) A)' is + canonicalized as `(minus A (mult B C))'. + + * For the `compare' operator, a constant is always the second operand + if the first argument is a condition code register or `(cc0)'. + + * An operand of `neg', `not', `mult', `plus', or `minus' is made the + first operand under the same conditions as above. + + * `(ltu (plus A B) B)' is converted to `(ltu (plus A B) A)'. + Likewise with `geu' instead of `ltu'. + + * `(minus X (const_int N))' is converted to `(plus X (const_int + -N))'. + + * Within address computations (i.e., inside `mem'), a left shift is + converted into the appropriate multiplication by a power of two. + + * De Morgan's Law is used to move bitwise negation inside a bitwise + logical-and or logical-or operation. If this results in only one + operand being a `not' expression, it will be the first one. + + A machine that has an instruction that performs a bitwise + logical-and of one operand with the bitwise negation of the other + should specify the pattern for that instruction as + + (define_insn "" + [(set (match_operand:M 0 ...) + (and:M (not:M (match_operand:M 1 ...)) + (match_operand:M 2 ...)))] + "..." + "...") + + Similarly, a pattern for a "NAND" instruction should be written + + (define_insn "" + [(set (match_operand:M 0 ...) + (ior:M (not:M (match_operand:M 1 ...)) + (not:M (match_operand:M 2 ...))))] + "..." + "...") + + In both cases, it is not necessary to include patterns for the many + logically equivalent RTL expressions. + + * The only possible RTL expressions involving both bitwise + exclusive-or and bitwise negation are `(xor:M X Y)' and `(not:M + (xor:M X Y))'. + + * The sum of three items, one of which is a constant, will only + appear in the form + + (plus:M (plus:M X Y) CONSTANT) + + * Equality comparisons of a group of bits (usually a single bit) + with zero will be written using `zero_extract' rather than the + equivalent `and' or `sign_extract' operations. + + + Further canonicalization rules are defined in the function +`commutative_operand_precedence' in `gcc/rtlanal.c'. + + +File: gccint.info, Node: Expander Definitions, Next: Insn Splitting, Prev: Insn Canonicalizations, Up: Machine Desc + +16.15 Defining RTL Sequences for Code Generation +================================================ + +On some target machines, some standard pattern names for RTL generation +cannot be handled with single insn, but a sequence of RTL insns can +represent them. For these target machines, you can write a +`define_expand' to specify how to generate the sequence of RTL. + + A `define_expand' is an RTL expression that looks almost like a +`define_insn'; but, unlike the latter, a `define_expand' is used only +for RTL generation and it can produce more than one RTL insn. + + A `define_expand' RTX has four operands: + + * The name. Each `define_expand' must have a name, since the only + use for it is to refer to it by name. + + * The RTL template. This is a vector of RTL expressions representing + a sequence of separate instructions. Unlike `define_insn', there + is no implicit surrounding `PARALLEL'. + + * The condition, a string containing a C expression. This + expression is used to express how the availability of this pattern + depends on subclasses of target machine, selected by command-line + options when GCC is run. This is just like the condition of a + `define_insn' that has a standard name. Therefore, the condition + (if present) may not depend on the data in the insn being matched, + but only the target-machine-type flags. The compiler needs to + test these conditions during initialization in order to learn + exactly which named instructions are available in a particular run. + + * The preparation statements, a string containing zero or more C + statements which are to be executed before RTL code is generated + from the RTL template. + + Usually these statements prepare temporary registers for use as + internal operands in the RTL template, but they can also generate + RTL insns directly by calling routines such as `emit_insn', etc. + Any such insns precede the ones that come from the RTL template. + + Every RTL insn emitted by a `define_expand' must match some +`define_insn' in the machine description. Otherwise, the compiler will +crash when trying to generate code for the insn or trying to optimize +it. + + The RTL template, in addition to controlling generation of RTL insns, +also describes the operands that need to be specified when this pattern +is used. In particular, it gives a predicate for each operand. + + A true operand, which needs to be specified in order to generate RTL +from the pattern, should be described with a `match_operand' in its +first occurrence in the RTL template. This enters information on the +operand's predicate into the tables that record such things. GCC uses +the information to preload the operand into a register if that is +required for valid RTL code. If the operand is referred to more than +once, subsequent references should use `match_dup'. + + The RTL template may also refer to internal "operands" which are +temporary registers or labels used only within the sequence made by the +`define_expand'. Internal operands are substituted into the RTL +template with `match_dup', never with `match_operand'. The values of +the internal operands are not passed in as arguments by the compiler +when it requests use of this pattern. Instead, they are computed +within the pattern, in the preparation statements. These statements +compute the values and store them into the appropriate elements of +`operands' so that `match_dup' can find them. + + There are two special macros defined for use in the preparation +statements: `DONE' and `FAIL'. Use them with a following semicolon, as +a statement. + +`DONE' + Use the `DONE' macro to end RTL generation for the pattern. The + only RTL insns resulting from the pattern on this occasion will be + those already emitted by explicit calls to `emit_insn' within the + preparation statements; the RTL template will not be generated. + +`FAIL' + Make the pattern fail on this occasion. When a pattern fails, it + means that the pattern was not truly available. The calling + routines in the compiler will try other strategies for code + generation using other patterns. + + Failure is currently supported only for binary (addition, + multiplication, shifting, etc.) and bit-field (`extv', `extzv', + and `insv') operations. + + If the preparation falls through (invokes neither `DONE' nor `FAIL'), +then the `define_expand' acts like a `define_insn' in that the RTL +template is used to generate the insn. + + The RTL template is not used for matching, only for generating the +initial insn list. If the preparation statement always invokes `DONE' +or `FAIL', the RTL template may be reduced to a simple list of +operands, such as this example: + + (define_expand "addsi3" + [(match_operand:SI 0 "register_operand" "") + (match_operand:SI 1 "register_operand" "") + (match_operand:SI 2 "register_operand" "")] + "" + " + { + handle_add (operands[0], operands[1], operands[2]); + DONE; + }") + + Here is an example, the definition of left-shift for the SPUR chip: + + (define_expand "ashlsi3" + [(set (match_operand:SI 0 "register_operand" "") + (ashift:SI + (match_operand:SI 1 "register_operand" "") + (match_operand:SI 2 "nonmemory_operand" "")))] + "" + " + + { + if (GET_CODE (operands[2]) != CONST_INT + || (unsigned) INTVAL (operands[2]) > 3) + FAIL; + }") + +This example uses `define_expand' so that it can generate an RTL insn +for shifting when the shift-count is in the supported range of 0 to 3 +but fail in other cases where machine insns aren't available. When it +fails, the compiler tries another strategy using different patterns +(such as, a library call). + + If the compiler were able to handle nontrivial condition-strings in +patterns with names, then it would be possible to use a `define_insn' +in that case. Here is another case (zero-extension on the 68000) which +makes more use of the power of `define_expand': + + (define_expand "zero_extendhisi2" + [(set (match_operand:SI 0 "general_operand" "") + (const_int 0)) + (set (strict_low_part + (subreg:HI + (match_dup 0) + 0)) + (match_operand:HI 1 "general_operand" ""))] + "" + "operands[1] = make_safe_from (operands[1], operands[0]);") + +Here two RTL insns are generated, one to clear the entire output operand +and the other to copy the input operand into its low half. This +sequence is incorrect if the input operand refers to [the old value of] +the output operand, so the preparation statement makes sure this isn't +so. The function `make_safe_from' copies the `operands[1]' into a +temporary register if it refers to `operands[0]'. It does this by +emitting another RTL insn. + + Finally, a third example shows the use of an internal operand. +Zero-extension on the SPUR chip is done by `and'-ing the result against +a halfword mask. But this mask cannot be represented by a `const_int' +because the constant value is too large to be legitimate on this +machine. So it must be copied into a register with `force_reg' and +then the register used in the `and'. + + (define_expand "zero_extendhisi2" + [(set (match_operand:SI 0 "register_operand" "") + (and:SI (subreg:SI + (match_operand:HI 1 "register_operand" "") + 0) + (match_dup 2)))] + "" + "operands[2] + = force_reg (SImode, GEN_INT (65535)); ") + + _Note:_ If the `define_expand' is used to serve a standard binary or +unary arithmetic operation or a bit-field operation, then the last insn +it generates must not be a `code_label', `barrier' or `note'. It must +be an `insn', `jump_insn' or `call_insn'. If you don't need a real insn +at the end, emit an insn to copy the result of the operation into +itself. Such an insn will generate no code, but it can avoid problems +in the compiler. + + +File: gccint.info, Node: Insn Splitting, Next: Including Patterns, Prev: Expander Definitions, Up: Machine Desc + +16.16 Defining How to Split Instructions +======================================== + +There are two cases where you should specify how to split a pattern +into multiple insns. On machines that have instructions requiring +delay slots (*note Delay Slots::) or that have instructions whose +output is not available for multiple cycles (*note Processor pipeline +description::), the compiler phases that optimize these cases need to +be able to move insns into one-instruction delay slots. However, some +insns may generate more than one machine instruction. These insns +cannot be placed into a delay slot. + + Often you can rewrite the single insn as a list of individual insns, +each corresponding to one machine instruction. The disadvantage of +doing so is that it will cause the compilation to be slower and require +more space. If the resulting insns are too complex, it may also +suppress some optimizations. The compiler splits the insn if there is a +reason to believe that it might improve instruction or delay slot +scheduling. + + The insn combiner phase also splits putative insns. If three insns are +merged into one insn with a complex expression that cannot be matched by +some `define_insn' pattern, the combiner phase attempts to split the +complex pattern into two insns that are recognized. Usually it can +break the complex pattern into two patterns by splitting out some +subexpression. However, in some other cases, such as performing an +addition of a large constant in two insns on a RISC machine, the way to +split the addition into two insns is machine-dependent. + + The `define_split' definition tells the compiler how to split a +complex insn into several simpler insns. It looks like this: + + (define_split + [INSN-PATTERN] + "CONDITION" + [NEW-INSN-PATTERN-1 + NEW-INSN-PATTERN-2 + ...] + "PREPARATION-STATEMENTS") + + INSN-PATTERN is a pattern that needs to be split and CONDITION is the +final condition to be tested, as in a `define_insn'. When an insn +matching INSN-PATTERN and satisfying CONDITION is found, it is replaced +in the insn list with the insns given by NEW-INSN-PATTERN-1, +NEW-INSN-PATTERN-2, etc. + + The PREPARATION-STATEMENTS are similar to those statements that are +specified for `define_expand' (*note Expander Definitions::) and are +executed before the new RTL is generated to prepare for the generated +code or emit some insns whose pattern is not fixed. Unlike those in +`define_expand', however, these statements must not generate any new +pseudo-registers. Once reload has completed, they also must not +allocate any space in the stack frame. + + Patterns are matched against INSN-PATTERN in two different +circumstances. If an insn needs to be split for delay slot scheduling +or insn scheduling, the insn is already known to be valid, which means +that it must have been matched by some `define_insn' and, if +`reload_completed' is nonzero, is known to satisfy the constraints of +that `define_insn'. In that case, the new insn patterns must also be +insns that are matched by some `define_insn' and, if `reload_completed' +is nonzero, must also satisfy the constraints of those definitions. + + As an example of this usage of `define_split', consider the following +example from `a29k.md', which splits a `sign_extend' from `HImode' to +`SImode' into a pair of shift insns: + + (define_split + [(set (match_operand:SI 0 "gen_reg_operand" "") + (sign_extend:SI (match_operand:HI 1 "gen_reg_operand" "")))] + "" + [(set (match_dup 0) + (ashift:SI (match_dup 1) + (const_int 16))) + (set (match_dup 0) + (ashiftrt:SI (match_dup 0) + (const_int 16)))] + " + { operands[1] = gen_lowpart (SImode, operands[1]); }") + + When the combiner phase tries to split an insn pattern, it is always +the case that the pattern is _not_ matched by any `define_insn'. The +combiner pass first tries to split a single `set' expression and then +the same `set' expression inside a `parallel', but followed by a +`clobber' of a pseudo-reg to use as a scratch register. In these +cases, the combiner expects exactly two new insn patterns to be +generated. It will verify that these patterns match some `define_insn' +definitions, so you need not do this test in the `define_split' (of +course, there is no point in writing a `define_split' that will never +produce insns that match). + + Here is an example of this use of `define_split', taken from +`rs6000.md': + + (define_split + [(set (match_operand:SI 0 "gen_reg_operand" "") + (plus:SI (match_operand:SI 1 "gen_reg_operand" "") + (match_operand:SI 2 "non_add_cint_operand" "")))] + "" + [(set (match_dup 0) (plus:SI (match_dup 1) (match_dup 3))) + (set (match_dup 0) (plus:SI (match_dup 0) (match_dup 4)))] + " + { + int low = INTVAL (operands[2]) & 0xffff; + int high = (unsigned) INTVAL (operands[2]) >> 16; + + if (low & 0x8000) + high++, low |= 0xffff0000; + + operands[3] = GEN_INT (high << 16); + operands[4] = GEN_INT (low); + }") + + Here the predicate `non_add_cint_operand' matches any `const_int' that +is _not_ a valid operand of a single add insn. The add with the +smaller displacement is written so that it can be substituted into the +address of a subsequent operation. + + An example that uses a scratch register, from the same file, generates +an equality comparison of a register and a large constant: + + (define_split + [(set (match_operand:CC 0 "cc_reg_operand" "") + (compare:CC (match_operand:SI 1 "gen_reg_operand" "") + (match_operand:SI 2 "non_short_cint_operand" ""))) + (clobber (match_operand:SI 3 "gen_reg_operand" ""))] + "find_single_use (operands[0], insn, 0) + && (GET_CODE (*find_single_use (operands[0], insn, 0)) == EQ + || GET_CODE (*find_single_use (operands[0], insn, 0)) == NE)" + [(set (match_dup 3) (xor:SI (match_dup 1) (match_dup 4))) + (set (match_dup 0) (compare:CC (match_dup 3) (match_dup 5)))] + " + { + /* Get the constant we are comparing against, C, and see what it + looks like sign-extended to 16 bits. Then see what constant + could be XOR'ed with C to get the sign-extended value. */ + + int c = INTVAL (operands[2]); + int sextc = (c << 16) >> 16; + int xorv = c ^ sextc; + + operands[4] = GEN_INT (xorv); + operands[5] = GEN_INT (sextc); + }") + + To avoid confusion, don't write a single `define_split' that accepts +some insns that match some `define_insn' as well as some insns that +don't. Instead, write two separate `define_split' definitions, one for +the insns that are valid and one for the insns that are not valid. + + The splitter is allowed to split jump instructions into sequence of +jumps or create new jumps in while splitting non-jump instructions. As +the central flowgraph and branch prediction information needs to be +updated, several restriction apply. + + Splitting of jump instruction into sequence that over by another jump +instruction is always valid, as compiler expect identical behavior of +new jump. When new sequence contains multiple jump instructions or new +labels, more assistance is needed. Splitter is required to create only +unconditional jumps, or simple conditional jump instructions. +Additionally it must attach a `REG_BR_PROB' note to each conditional +jump. A global variable `split_branch_probability' holds the +probability of the original branch in case it was a simple conditional +jump, -1 otherwise. To simplify recomputing of edge frequencies, the +new sequence is required to have only forward jumps to the newly +created labels. + + For the common case where the pattern of a define_split exactly +matches the pattern of a define_insn, use `define_insn_and_split'. It +looks like this: + + (define_insn_and_split + [INSN-PATTERN] + "CONDITION" + "OUTPUT-TEMPLATE" + "SPLIT-CONDITION" + [NEW-INSN-PATTERN-1 + NEW-INSN-PATTERN-2 + ...] + "PREPARATION-STATEMENTS" + [INSN-ATTRIBUTES]) + + INSN-PATTERN, CONDITION, OUTPUT-TEMPLATE, and INSN-ATTRIBUTES are used +as in `define_insn'. The NEW-INSN-PATTERN vector and the +PREPARATION-STATEMENTS are used as in a `define_split'. The +SPLIT-CONDITION is also used as in `define_split', with the additional +behavior that if the condition starts with `&&', the condition used for +the split will be the constructed as a logical "and" of the split +condition with the insn condition. For example, from i386.md: + + (define_insn_and_split "zero_extendhisi2_and" + [(set (match_operand:SI 0 "register_operand" "=r") + (zero_extend:SI (match_operand:HI 1 "register_operand" "0"))) + (clobber (reg:CC 17))] + "TARGET_ZERO_EXTEND_WITH_AND && !optimize_size" + "#" + "&& reload_completed" + [(parallel [(set (match_dup 0) + (and:SI (match_dup 0) (const_int 65535))) + (clobber (reg:CC 17))])] + "" + [(set_attr "type" "alu1")]) + + In this case, the actual split condition will be +`TARGET_ZERO_EXTEND_WITH_AND && !optimize_size && reload_completed'. + + The `define_insn_and_split' construction provides exactly the same +functionality as two separate `define_insn' and `define_split' +patterns. It exists for compactness, and as a maintenance tool to +prevent having to ensure the two patterns' templates match. + + +File: gccint.info, Node: Including Patterns, Next: Peephole Definitions, Prev: Insn Splitting, Up: Machine Desc + +16.17 Including Patterns in Machine Descriptions. +================================================= + +The `include' pattern tells the compiler tools where to look for +patterns that are in files other than in the file `.md'. This is used +only at build time and there is no preprocessing allowed. + + It looks like: + + + (include + PATHNAME) + + For example: + + + (include "filestuff") + + Where PATHNAME is a string that specifies the location of the file, +specifies the include file to be in `gcc/config/target/filestuff'. The +directory `gcc/config/target' is regarded as the default directory. + + Machine descriptions may be split up into smaller more manageable +subsections and placed into subdirectories. + + By specifying: + + + (include "BOGUS/filestuff") + + the include file is specified to be in +`gcc/config/TARGET/BOGUS/filestuff'. + + Specifying an absolute path for the include file such as; + + (include "/u2/BOGUS/filestuff") + is permitted but is not encouraged. + +16.17.1 RTL Generation Tool Options for Directory Search +-------------------------------------------------------- + +The `-IDIR' option specifies directories to search for machine +descriptions. For example: + + + genrecog -I/p1/abc/proc1 -I/p2/abcd/pro2 target.md + + Add the directory DIR to the head of the list of directories to be +searched for header files. This can be used to override a system +machine definition file, substituting your own version, since these +directories are searched before the default machine description file +directories. If you use more than one `-I' option, the directories are +scanned in left-to-right order; the standard default directory come +after. + + +File: gccint.info, Node: Peephole Definitions, Next: Insn Attributes, Prev: Including Patterns, Up: Machine Desc + +16.18 Machine-Specific Peephole Optimizers +========================================== + +In addition to instruction patterns the `md' file may contain +definitions of machine-specific peephole optimizations. + + The combiner does not notice certain peephole optimizations when the +data flow in the program does not suggest that it should try them. For +example, sometimes two consecutive insns related in purpose can be +combined even though the second one does not appear to use a register +computed in the first one. A machine-specific peephole optimizer can +detect such opportunities. + + There are two forms of peephole definitions that may be used. The +original `define_peephole' is run at assembly output time to match +insns and substitute assembly text. Use of `define_peephole' is +deprecated. + + A newer `define_peephole2' matches insns and substitutes new insns. +The `peephole2' pass is run after register allocation but before +scheduling, which may result in much better code for targets that do +scheduling. + +* Menu: + +* define_peephole:: RTL to Text Peephole Optimizers +* define_peephole2:: RTL to RTL Peephole Optimizers + + +File: gccint.info, Node: define_peephole, Next: define_peephole2, Up: Peephole Definitions + +16.18.1 RTL to Text Peephole Optimizers +--------------------------------------- + +A definition looks like this: + + (define_peephole + [INSN-PATTERN-1 + INSN-PATTERN-2 + ...] + "CONDITION" + "TEMPLATE" + "OPTIONAL-INSN-ATTRIBUTES") + +The last string operand may be omitted if you are not using any +machine-specific information in this machine description. If present, +it must obey the same rules as in a `define_insn'. + + In this skeleton, INSN-PATTERN-1 and so on are patterns to match +consecutive insns. The optimization applies to a sequence of insns when +INSN-PATTERN-1 matches the first one, INSN-PATTERN-2 matches the next, +and so on. + + Each of the insns matched by a peephole must also match a +`define_insn'. Peepholes are checked only at the last stage just +before code generation, and only optionally. Therefore, any insn which +would match a peephole but no `define_insn' will cause a crash in code +generation in an unoptimized compilation, or at various optimization +stages. + + The operands of the insns are matched with `match_operands', +`match_operator', and `match_dup', as usual. What is not usual is that +the operand numbers apply to all the insn patterns in the definition. +So, you can check for identical operands in two insns by using +`match_operand' in one insn and `match_dup' in the other. + + The operand constraints used in `match_operand' patterns do not have +any direct effect on the applicability of the peephole, but they will +be validated afterward, so make sure your constraints are general enough +to apply whenever the peephole matches. If the peephole matches but +the constraints are not satisfied, the compiler will crash. + + It is safe to omit constraints in all the operands of the peephole; or +you can write constraints which serve as a double-check on the criteria +previously tested. + + Once a sequence of insns matches the patterns, the CONDITION is +checked. This is a C expression which makes the final decision whether +to perform the optimization (we do so if the expression is nonzero). If +CONDITION is omitted (in other words, the string is empty) then the +optimization is applied to every sequence of insns that matches the +patterns. + + The defined peephole optimizations are applied after register +allocation is complete. Therefore, the peephole definition can check +which operands have ended up in which kinds of registers, just by +looking at the operands. + + The way to refer to the operands in CONDITION is to write +`operands[I]' for operand number I (as matched by `(match_operand I +...)'). Use the variable `insn' to refer to the last of the insns +being matched; use `prev_active_insn' to find the preceding insns. + + When optimizing computations with intermediate results, you can use +CONDITION to match only when the intermediate results are not used +elsewhere. Use the C expression `dead_or_set_p (INSN, OP)', where INSN +is the insn in which you expect the value to be used for the last time +(from the value of `insn', together with use of `prev_nonnote_insn'), +and OP is the intermediate value (from `operands[I]'). + + Applying the optimization means replacing the sequence of insns with +one new insn. The TEMPLATE controls ultimate output of assembler code +for this combined insn. It works exactly like the template of a +`define_insn'. Operand numbers in this template are the same ones used +in matching the original sequence of insns. + + The result of a defined peephole optimizer does not need to match any +of the insn patterns in the machine description; it does not even have +an opportunity to match them. The peephole optimizer definition itself +serves as the insn pattern to control how the insn is output. + + Defined peephole optimizers are run as assembler code is being output, +so the insns they produce are never combined or rearranged in any way. + + Here is an example, taken from the 68000 machine description: + + (define_peephole + [(set (reg:SI 15) (plus:SI (reg:SI 15) (const_int 4))) + (set (match_operand:DF 0 "register_operand" "=f") + (match_operand:DF 1 "register_operand" "ad"))] + "FP_REG_P (operands[0]) && ! FP_REG_P (operands[1])" + { + rtx xoperands[2]; + xoperands[1] = gen_rtx_REG (SImode, REGNO (operands[1]) + 1); + #ifdef MOTOROLA + output_asm_insn ("move.l %1,(sp)", xoperands); + output_asm_insn ("move.l %1,-(sp)", operands); + return "fmove.d (sp)+,%0"; + #else + output_asm_insn ("movel %1,sp@", xoperands); + output_asm_insn ("movel %1,sp@-", operands); + return "fmoved sp@+,%0"; + #endif + }) + + The effect of this optimization is to change + + jbsr _foobar + addql #4,sp + movel d1,sp@- + movel d0,sp@- + fmoved sp@+,fp0 + +into + + jbsr _foobar + movel d1,sp@ + movel d0,sp@- + fmoved sp@+,fp0 + + INSN-PATTERN-1 and so on look _almost_ like the second operand of +`define_insn'. There is one important difference: the second operand +of `define_insn' consists of one or more RTX's enclosed in square +brackets. Usually, there is only one: then the same action can be +written as an element of a `define_peephole'. But when there are +multiple actions in a `define_insn', they are implicitly enclosed in a +`parallel'. Then you must explicitly write the `parallel', and the +square brackets within it, in the `define_peephole'. Thus, if an insn +pattern looks like this, + + (define_insn "divmodsi4" + [(set (match_operand:SI 0 "general_operand" "=d") + (div:SI (match_operand:SI 1 "general_operand" "0") + (match_operand:SI 2 "general_operand" "dmsK"))) + (set (match_operand:SI 3 "general_operand" "=d") + (mod:SI (match_dup 1) (match_dup 2)))] + "TARGET_68020" + "divsl%.l %2,%3:%0") + +then the way to mention this insn in a peephole is as follows: + + (define_peephole + [... + (parallel + [(set (match_operand:SI 0 "general_operand" "=d") + (div:SI (match_operand:SI 1 "general_operand" "0") + (match_operand:SI 2 "general_operand" "dmsK"))) + (set (match_operand:SI 3 "general_operand" "=d") + (mod:SI (match_dup 1) (match_dup 2)))]) + ...] + ...) + + +File: gccint.info, Node: define_peephole2, Prev: define_peephole, Up: Peephole Definitions + +16.18.2 RTL to RTL Peephole Optimizers +-------------------------------------- + +The `define_peephole2' definition tells the compiler how to substitute +one sequence of instructions for another sequence, what additional +scratch registers may be needed and what their lifetimes must be. + + (define_peephole2 + [INSN-PATTERN-1 + INSN-PATTERN-2 + ...] + "CONDITION" + [NEW-INSN-PATTERN-1 + NEW-INSN-PATTERN-2 + ...] + "PREPARATION-STATEMENTS") + + The definition is almost identical to `define_split' (*note Insn +Splitting::) except that the pattern to match is not a single +instruction, but a sequence of instructions. + + It is possible to request additional scratch registers for use in the +output template. If appropriate registers are not free, the pattern +will simply not match. + + Scratch registers are requested with a `match_scratch' pattern at the +top level of the input pattern. The allocated register (initially) will +be dead at the point requested within the original sequence. If the +scratch is used at more than a single point, a `match_dup' pattern at +the top level of the input pattern marks the last position in the input +sequence at which the register must be available. + + Here is an example from the IA-32 machine description: + + (define_peephole2 + [(match_scratch:SI 2 "r") + (parallel [(set (match_operand:SI 0 "register_operand" "") + (match_operator:SI 3 "arith_or_logical_operator" + [(match_dup 0) + (match_operand:SI 1 "memory_operand" "")])) + (clobber (reg:CC 17))])] + "! optimize_size && ! TARGET_READ_MODIFY" + [(set (match_dup 2) (match_dup 1)) + (parallel [(set (match_dup 0) + (match_op_dup 3 [(match_dup 0) (match_dup 2)])) + (clobber (reg:CC 17))])] + "") + +This pattern tries to split a load from its use in the hopes that we'll +be able to schedule around the memory load latency. It allocates a +single `SImode' register of class `GENERAL_REGS' (`"r"') that needs to +be live only at the point just before the arithmetic. + + A real example requiring extended scratch lifetimes is harder to come +by, so here's a silly made-up example: + + (define_peephole2 + [(match_scratch:SI 4 "r") + (set (match_operand:SI 0 "" "") (match_operand:SI 1 "" "")) + (set (match_operand:SI 2 "" "") (match_dup 1)) + (match_dup 4) + (set (match_operand:SI 3 "" "") (match_dup 1))] + "/* determine 1 does not overlap 0 and 2 */" + [(set (match_dup 4) (match_dup 1)) + (set (match_dup 0) (match_dup 4)) + (set (match_dup 2) (match_dup 4))] + (set (match_dup 3) (match_dup 4))] + "") + +If we had not added the `(match_dup 4)' in the middle of the input +sequence, it might have been the case that the register we chose at the +beginning of the sequence is killed by the first or second `set'. + + +File: gccint.info, Node: Insn Attributes, Next: Conditional Execution, Prev: Peephole Definitions, Up: Machine Desc + +16.19 Instruction Attributes +============================ + +In addition to describing the instruction supported by the target +machine, the `md' file also defines a group of "attributes" and a set of +values for each. Every generated insn is assigned a value for each +attribute. One possible attribute would be the effect that the insn +has on the machine's condition code. This attribute can then be used +by `NOTICE_UPDATE_CC' to track the condition codes. + +* Menu: + +* Defining Attributes:: Specifying attributes and their values. +* Expressions:: Valid expressions for attribute values. +* Tagging Insns:: Assigning attribute values to insns. +* Attr Example:: An example of assigning attributes. +* Insn Lengths:: Computing the length of insns. +* Constant Attributes:: Defining attributes that are constant. +* Delay Slots:: Defining delay slots required for a machine. +* Processor pipeline description:: Specifying information for insn scheduling. + + +File: gccint.info, Node: Defining Attributes, Next: Expressions, Up: Insn Attributes + +16.19.1 Defining Attributes and their Values +-------------------------------------------- + +The `define_attr' expression is used to define each attribute required +by the target machine. It looks like: + + (define_attr NAME LIST-OF-VALUES DEFAULT) + + NAME is a string specifying the name of the attribute being defined. + + LIST-OF-VALUES is either a string that specifies a comma-separated +list of values that can be assigned to the attribute, or a null string +to indicate that the attribute takes numeric values. + + DEFAULT is an attribute expression that gives the value of this +attribute for insns that match patterns whose definition does not +include an explicit value for this attribute. *Note Attr Example::, +for more information on the handling of defaults. *Note Constant +Attributes::, for information on attributes that do not depend on any +particular insn. + + For each defined attribute, a number of definitions are written to the +`insn-attr.h' file. For cases where an explicit set of values is +specified for an attribute, the following are defined: + + * A `#define' is written for the symbol `HAVE_ATTR_NAME'. + + * An enumerated class is defined for `attr_NAME' with elements of + the form `UPPER-NAME_UPPER-VALUE' where the attribute name and + value are first converted to uppercase. + + * A function `get_attr_NAME' is defined that is passed an insn and + returns the attribute value for that insn. + + For example, if the following is present in the `md' file: + + (define_attr "type" "branch,fp,load,store,arith" ...) + +the following lines will be written to the file `insn-attr.h'. + + #define HAVE_ATTR_type + enum attr_type {TYPE_BRANCH, TYPE_FP, TYPE_LOAD, + TYPE_STORE, TYPE_ARITH}; + extern enum attr_type get_attr_type (); + + If the attribute takes numeric values, no `enum' type will be defined +and the function to obtain the attribute's value will return `int'. + + There are attributes which are tied to a specific meaning. These +attributes are not free to use for other purposes: + +`length' + The `length' attribute is used to calculate the length of emitted + code chunks. This is especially important when verifying branch + distances. *Note Insn Lengths::. + +`enabled' + The `enabled' attribute can be defined to prevent certain + alternatives of an insn definition from being used during code + generation. *Note Disable Insn Alternatives::. + + Another way of defining an attribute is to use: + + (define_enum_attr "ATTR" "ENUM" DEFAULT) + + This works in just the same way as `define_attr', except that the list +of values is taken from a separate enumeration called ENUM (*note +define_enum::). This form allows you to use the same list of values +for several attributes without having to repeat the list each time. +For example: + + (define_enum "processor" [ + model_a + model_b + ... + ]) + (define_enum_attr "arch" "processor" + (const (symbol_ref "target_arch"))) + (define_enum_attr "tune" "processor" + (const (symbol_ref "target_tune"))) + + defines the same attributes as: + + (define_attr "arch" "model_a,model_b,..." + (const (symbol_ref "target_arch"))) + (define_attr "tune" "model_a,model_b,..." + (const (symbol_ref "target_tune"))) + + but without duplicating the processor list. The second example +defines two separate C enums (`attr_arch' and `attr_tune') whereas the +first defines a single C enum (`processor'). + + +File: gccint.info, Node: Expressions, Next: Tagging Insns, Prev: Defining Attributes, Up: Insn Attributes + +16.19.2 Attribute Expressions +----------------------------- + +RTL expressions used to define attributes use the codes described above +plus a few specific to attribute definitions, to be discussed below. +Attribute value expressions must have one of the following forms: + +`(const_int I)' + The integer I specifies the value of a numeric attribute. I must + be non-negative. + + The value of a numeric attribute can be specified either with a + `const_int', or as an integer represented as a string in + `const_string', `eq_attr' (see below), `attr', `symbol_ref', + simple arithmetic expressions, and `set_attr' overrides on + specific instructions (*note Tagging Insns::). + +`(const_string VALUE)' + The string VALUE specifies a constant attribute value. If VALUE + is specified as `"*"', it means that the default value of the + attribute is to be used for the insn containing this expression. + `"*"' obviously cannot be used in the DEFAULT expression of a + `define_attr'. + + If the attribute whose value is being specified is numeric, VALUE + must be a string containing a non-negative integer (normally + `const_int' would be used in this case). Otherwise, it must + contain one of the valid values for the attribute. + +`(if_then_else TEST TRUE-VALUE FALSE-VALUE)' + TEST specifies an attribute test, whose format is defined below. + The value of this expression is TRUE-VALUE if TEST is true, + otherwise it is FALSE-VALUE. + +`(cond [TEST1 VALUE1 ...] DEFAULT)' + The first operand of this expression is a vector containing an even + number of expressions and consisting of pairs of TEST and VALUE + expressions. The value of the `cond' expression is that of the + VALUE corresponding to the first true TEST expression. If none of + the TEST expressions are true, the value of the `cond' expression + is that of the DEFAULT expression. + + TEST expressions can have one of the following forms: + +`(const_int I)' + This test is true if I is nonzero and false otherwise. + +`(not TEST)' +`(ior TEST1 TEST2)' +`(and TEST1 TEST2)' + These tests are true if the indicated logical function is true. + +`(match_operand:M N PRED CONSTRAINTS)' + This test is true if operand N of the insn whose attribute value + is being determined has mode M (this part of the test is ignored + if M is `VOIDmode') and the function specified by the string PRED + returns a nonzero value when passed operand N and mode M (this + part of the test is ignored if PRED is the null string). + + The CONSTRAINTS operand is ignored and should be the null string. + +`(le ARITH1 ARITH2)' +`(leu ARITH1 ARITH2)' +`(lt ARITH1 ARITH2)' +`(ltu ARITH1 ARITH2)' +`(gt ARITH1 ARITH2)' +`(gtu ARITH1 ARITH2)' +`(ge ARITH1 ARITH2)' +`(geu ARITH1 ARITH2)' +`(ne ARITH1 ARITH2)' +`(eq ARITH1 ARITH2)' + These tests are true if the indicated comparison of the two + arithmetic expressions is true. Arithmetic expressions are formed + with `plus', `minus', `mult', `div', `mod', `abs', `neg', `and', + `ior', `xor', `not', `ashift', `lshiftrt', and `ashiftrt' + expressions. + + `const_int' and `symbol_ref' are always valid terms (*note Insn + Lengths::,for additional forms). `symbol_ref' is a string + denoting a C expression that yields an `int' when evaluated by the + `get_attr_...' routine. It should normally be a global variable. + +`(eq_attr NAME VALUE)' + NAME is a string specifying the name of an attribute. + + VALUE is a string that is either a valid value for attribute NAME, + a comma-separated list of values, or `!' followed by a value or + list. If VALUE does not begin with a `!', this test is true if + the value of the NAME attribute of the current insn is in the list + specified by VALUE. If VALUE begins with a `!', this test is true + if the attribute's value is _not_ in the specified list. + + For example, + + (eq_attr "type" "load,store") + + is equivalent to + + (ior (eq_attr "type" "load") (eq_attr "type" "store")) + + If NAME specifies an attribute of `alternative', it refers to the + value of the compiler variable `which_alternative' (*note Output + Statement::) and the values must be small integers. For example, + + (eq_attr "alternative" "2,3") + + is equivalent to + + (ior (eq (symbol_ref "which_alternative") (const_int 2)) + (eq (symbol_ref "which_alternative") (const_int 3))) + + Note that, for most attributes, an `eq_attr' test is simplified in + cases where the value of the attribute being tested is known for + all insns matching a particular pattern. This is by far the most + common case. + +`(attr_flag NAME)' + The value of an `attr_flag' expression is true if the flag + specified by NAME is true for the `insn' currently being scheduled. + + NAME is a string specifying one of a fixed set of flags to test. + Test the flags `forward' and `backward' to determine the direction + of a conditional branch. Test the flags `very_likely', `likely', + `very_unlikely', and `unlikely' to determine if a conditional + branch is expected to be taken. + + If the `very_likely' flag is true, then the `likely' flag is also + true. Likewise for the `very_unlikely' and `unlikely' flags. + + This example describes a conditional branch delay slot which can + be nullified for forward branches that are taken (annul-true) or + for backward branches which are not taken (annul-false). + + (define_delay (eq_attr "type" "cbranch") + [(eq_attr "in_branch_delay" "true") + (and (eq_attr "in_branch_delay" "true") + (attr_flag "forward")) + (and (eq_attr "in_branch_delay" "true") + (attr_flag "backward"))]) + + The `forward' and `backward' flags are false if the current `insn' + being scheduled is not a conditional branch. + + The `very_likely' and `likely' flags are true if the `insn' being + scheduled is not a conditional branch. The `very_unlikely' and + `unlikely' flags are false if the `insn' being scheduled is not a + conditional branch. + + `attr_flag' is only used during delay slot scheduling and has no + meaning to other passes of the compiler. + +`(attr NAME)' + The value of another attribute is returned. This is most useful + for numeric attributes, as `eq_attr' and `attr_flag' produce more + efficient code for non-numeric attributes. + + +File: gccint.info, Node: Tagging Insns, Next: Attr Example, Prev: Expressions, Up: Insn Attributes + +16.19.3 Assigning Attribute Values to Insns +------------------------------------------- + +The value assigned to an attribute of an insn is primarily determined by +which pattern is matched by that insn (or which `define_peephole' +generated it). Every `define_insn' and `define_peephole' can have an +optional last argument to specify the values of attributes for matching +insns. The value of any attribute not specified in a particular insn +is set to the default value for that attribute, as specified in its +`define_attr'. Extensive use of default values for attributes permits +the specification of the values for only one or two attributes in the +definition of most insn patterns, as seen in the example in the next +section. + + The optional last argument of `define_insn' and `define_peephole' is a +vector of expressions, each of which defines the value for a single +attribute. The most general way of assigning an attribute's value is +to use a `set' expression whose first operand is an `attr' expression +giving the name of the attribute being set. The second operand of the +`set' is an attribute expression (*note Expressions::) giving the value +of the attribute. + + When the attribute value depends on the `alternative' attribute (i.e., +which is the applicable alternative in the constraint of the insn), the +`set_attr_alternative' expression can be used. It allows the +specification of a vector of attribute expressions, one for each +alternative. + + When the generality of arbitrary attribute expressions is not required, +the simpler `set_attr' expression can be used, which allows specifying +a string giving either a single attribute value or a list of attribute +values, one for each alternative. + + The form of each of the above specifications is shown below. In each +case, NAME is a string specifying the attribute to be set. + +`(set_attr NAME VALUE-STRING)' + VALUE-STRING is either a string giving the desired attribute value, + or a string containing a comma-separated list giving the values for + succeeding alternatives. The number of elements must match the + number of alternatives in the constraint of the insn pattern. + + Note that it may be useful to specify `*' for some alternative, in + which case the attribute will assume its default value for insns + matching that alternative. + +`(set_attr_alternative NAME [VALUE1 VALUE2 ...])' + Depending on the alternative of the insn, the value will be one of + the specified values. This is a shorthand for using a `cond' with + tests on the `alternative' attribute. + +`(set (attr NAME) VALUE)' + The first operand of this `set' must be the special RTL expression + `attr', whose sole operand is a string giving the name of the + attribute being set. VALUE is the value of the attribute. + + The following shows three different ways of representing the same +attribute value specification: + + (set_attr "type" "load,store,arith") + + (set_attr_alternative "type" + [(const_string "load") (const_string "store") + (const_string "arith")]) + + (set (attr "type") + (cond [(eq_attr "alternative" "1") (const_string "load") + (eq_attr "alternative" "2") (const_string "store")] + (const_string "arith"))) + + The `define_asm_attributes' expression provides a mechanism to specify +the attributes assigned to insns produced from an `asm' statement. It +has the form: + + (define_asm_attributes [ATTR-SETS]) + +where ATTR-SETS is specified the same as for both the `define_insn' and +the `define_peephole' expressions. + + These values will typically be the "worst case" attribute values. For +example, they might indicate that the condition code will be clobbered. + + A specification for a `length' attribute is handled specially. The +way to compute the length of an `asm' insn is to multiply the length +specified in the expression `define_asm_attributes' by the number of +machine instructions specified in the `asm' statement, determined by +counting the number of semicolons and newlines in the string. +Therefore, the value of the `length' attribute specified in a +`define_asm_attributes' should be the maximum possible length of a +single machine instruction. + + +File: gccint.info, Node: Attr Example, Next: Insn Lengths, Prev: Tagging Insns, Up: Insn Attributes + +16.19.4 Example of Attribute Specifications +------------------------------------------- + +The judicious use of defaulting is important in the efficient use of +insn attributes. Typically, insns are divided into "types" and an +attribute, customarily called `type', is used to represent this value. +This attribute is normally used only to define the default value for +other attributes. An example will clarify this usage. + + Assume we have a RISC machine with a condition code and in which only +full-word operations are performed in registers. Let us assume that we +can divide all insns into loads, stores, (integer) arithmetic +operations, floating point operations, and branches. + + Here we will concern ourselves with determining the effect of an insn +on the condition code and will limit ourselves to the following possible +effects: The condition code can be set unpredictably (clobbered), not +be changed, be set to agree with the results of the operation, or only +changed if the item previously set into the condition code has been +modified. + + Here is part of a sample `md' file for such a machine: + + (define_attr "type" "load,store,arith,fp,branch" (const_string "arith")) + + (define_attr "cc" "clobber,unchanged,set,change0" + (cond [(eq_attr "type" "load") + (const_string "change0") + (eq_attr "type" "store,branch") + (const_string "unchanged") + (eq_attr "type" "arith") + (if_then_else (match_operand:SI 0 "" "") + (const_string "set") + (const_string "clobber"))] + (const_string "clobber"))) + + (define_insn "" + [(set (match_operand:SI 0 "general_operand" "=r,r,m") + (match_operand:SI 1 "general_operand" "r,m,r"))] + "" + "@ + move %0,%1 + load %0,%1 + store %0,%1" + [(set_attr "type" "arith,load,store")]) + + Note that we assume in the above example that arithmetic operations +performed on quantities smaller than a machine word clobber the +condition code since they will set the condition code to a value +corresponding to the full-word result. + + +File: gccint.info, Node: Insn Lengths, Next: Constant Attributes, Prev: Attr Example, Up: Insn Attributes + +16.19.5 Computing the Length of an Insn +--------------------------------------- + +For many machines, multiple types of branch instructions are provided, +each for different length branch displacements. In most cases, the +assembler will choose the correct instruction to use. However, when +the assembler cannot do so, GCC can when a special attribute, the +`length' attribute, is defined. This attribute must be defined to have +numeric values by specifying a null string in its `define_attr'. + + In the case of the `length' attribute, two additional forms of +arithmetic terms are allowed in test expressions: + +`(match_dup N)' + This refers to the address of operand N of the current insn, which + must be a `label_ref'. + +`(pc)' + This refers to the address of the _current_ insn. It might have + been more consistent with other usage to make this the address of + the _next_ insn but this would be confusing because the length of + the current insn is to be computed. + + For normal insns, the length will be determined by value of the +`length' attribute. In the case of `addr_vec' and `addr_diff_vec' insn +patterns, the length is computed as the number of vectors multiplied by +the size of each vector. + + Lengths are measured in addressable storage units (bytes). + + The following macros can be used to refine the length computation: + +`ADJUST_INSN_LENGTH (INSN, LENGTH)' + If defined, modifies the length assigned to instruction INSN as a + function of the context in which it is used. LENGTH is an lvalue + that contains the initially computed length of the insn and should + be updated with the correct length of the insn. + + This macro will normally not be required. A case in which it is + required is the ROMP. On this machine, the size of an `addr_vec' + insn must be increased by two to compensate for the fact that + alignment may be required. + + The routine that returns `get_attr_length' (the value of the `length' +attribute) can be used by the output routine to determine the form of +the branch instruction to be written, as the example below illustrates. + + As an example of the specification of variable-length branches, +consider the IBM 360. If we adopt the convention that a register will +be set to the starting address of a function, we can jump to labels +within 4k of the start using a four-byte instruction. Otherwise, we +need a six-byte sequence to load the address from memory and then +branch to it. + + On such a machine, a pattern for a branch instruction might be +specified as follows: + + (define_insn "jump" + [(set (pc) + (label_ref (match_operand 0 "" "")))] + "" + { + return (get_attr_length (insn) == 4 + ? "b %l0" : "l r15,=a(%l0); br r15"); + } + [(set (attr "length") + (if_then_else (lt (match_dup 0) (const_int 4096)) + (const_int 4) + (const_int 6)))]) + + +File: gccint.info, Node: Constant Attributes, Next: Delay Slots, Prev: Insn Lengths, Up: Insn Attributes + +16.19.6 Constant Attributes +--------------------------- + +A special form of `define_attr', where the expression for the default +value is a `const' expression, indicates an attribute that is constant +for a given run of the compiler. Constant attributes may be used to +specify which variety of processor is used. For example, + + (define_attr "cpu" "m88100,m88110,m88000" + (const + (cond [(symbol_ref "TARGET_88100") (const_string "m88100") + (symbol_ref "TARGET_88110") (const_string "m88110")] + (const_string "m88000")))) + + (define_attr "memory" "fast,slow" + (const + (if_then_else (symbol_ref "TARGET_FAST_MEM") + (const_string "fast") + (const_string "slow")))) + + The routine generated for constant attributes has no parameters as it +does not depend on any particular insn. RTL expressions used to define +the value of a constant attribute may use the `symbol_ref' form, but +may not use either the `match_operand' form or `eq_attr' forms +involving insn attributes. + + +File: gccint.info, Node: Delay Slots, Next: Processor pipeline description, Prev: Constant Attributes, Up: Insn Attributes + +16.19.7 Delay Slot Scheduling +----------------------------- + +The insn attribute mechanism can be used to specify the requirements for +delay slots, if any, on a target machine. An instruction is said to +require a "delay slot" if some instructions that are physically after +the instruction are executed as if they were located before it. +Classic examples are branch and call instructions, which often execute +the following instruction before the branch or call is performed. + + On some machines, conditional branch instructions can optionally +"annul" instructions in the delay slot. This means that the +instruction will not be executed for certain branch outcomes. Both +instructions that annul if the branch is true and instructions that +annul if the branch is false are supported. + + Delay slot scheduling differs from instruction scheduling in that +determining whether an instruction needs a delay slot is dependent only +on the type of instruction being generated, not on data flow between the +instructions. See the next section for a discussion of data-dependent +instruction scheduling. + + The requirement of an insn needing one or more delay slots is indicated +via the `define_delay' expression. It has the following form: + + (define_delay TEST + [DELAY-1 ANNUL-TRUE-1 ANNUL-FALSE-1 + DELAY-2 ANNUL-TRUE-2 ANNUL-FALSE-2 + ...]) + + TEST is an attribute test that indicates whether this `define_delay' +applies to a particular insn. If so, the number of required delay +slots is determined by the length of the vector specified as the second +argument. An insn placed in delay slot N must satisfy attribute test +DELAY-N. ANNUL-TRUE-N is an attribute test that specifies which insns +may be annulled if the branch is true. Similarly, ANNUL-FALSE-N +specifies which insns in the delay slot may be annulled if the branch +is false. If annulling is not supported for that delay slot, `(nil)' +should be coded. + + For example, in the common case where branch and call insns require a +single delay slot, which may contain any insn other than a branch or +call, the following would be placed in the `md' file: + + (define_delay (eq_attr "type" "branch,call") + [(eq_attr "type" "!branch,call") (nil) (nil)]) + + Multiple `define_delay' expressions may be specified. In this case, +each such expression specifies different delay slot requirements and +there must be no insn for which tests in two `define_delay' expressions +are both true. + + For example, if we have a machine that requires one delay slot for +branches but two for calls, no delay slot can contain a branch or call +insn, and any valid insn in the delay slot for the branch can be +annulled if the branch is true, we might represent this as follows: + + (define_delay (eq_attr "type" "branch") + [(eq_attr "type" "!branch,call") + (eq_attr "type" "!branch,call") + (nil)]) + + (define_delay (eq_attr "type" "call") + [(eq_attr "type" "!branch,call") (nil) (nil) + (eq_attr "type" "!branch,call") (nil) (nil)]) + + +File: gccint.info, Node: Processor pipeline description, Prev: Delay Slots, Up: Insn Attributes + +16.19.8 Specifying processor pipeline description +------------------------------------------------- + +To achieve better performance, most modern processors (super-pipelined, +superscalar RISC, and VLIW processors) have many "functional units" on +which several instructions can be executed simultaneously. An +instruction starts execution if its issue conditions are satisfied. If +not, the instruction is stalled until its conditions are satisfied. +Such "interlock (pipeline) delay" causes interruption of the fetching +of successor instructions (or demands nop instructions, e.g. for some +MIPS processors). + + There are two major kinds of interlock delays in modern processors. +The first one is a data dependence delay determining "instruction +latency time". The instruction execution is not started until all +source data have been evaluated by prior instructions (there are more +complex cases when the instruction execution starts even when the data +are not available but will be ready in given time after the instruction +execution start). Taking the data dependence delays into account is +simple. The data dependence (true, output, and anti-dependence) delay +between two instructions is given by a constant. In most cases this +approach is adequate. The second kind of interlock delays is a +reservation delay. The reservation delay means that two instructions +under execution will be in need of shared processors resources, i.e. +buses, internal registers, and/or functional units, which are reserved +for some time. Taking this kind of delay into account is complex +especially for modern RISC processors. + + The task of exploiting more processor parallelism is solved by an +instruction scheduler. For a better solution to this problem, the +instruction scheduler has to have an adequate description of the +processor parallelism (or "pipeline description"). GCC machine +descriptions describe processor parallelism and functional unit +reservations for groups of instructions with the aid of "regular +expressions". + + The GCC instruction scheduler uses a "pipeline hazard recognizer" to +figure out the possibility of the instruction issue by the processor on +a given simulated processor cycle. The pipeline hazard recognizer is +automatically generated from the processor pipeline description. The +pipeline hazard recognizer generated from the machine description is +based on a deterministic finite state automaton (DFA): the instruction +issue is possible if there is a transition from one automaton state to +another one. This algorithm is very fast, and furthermore, its speed +is not dependent on processor complexity(1). + + The rest of this section describes the directives that constitute an +automaton-based processor pipeline description. The order of these +constructions within the machine description file is not important. + + The following optional construction describes names of automata +generated and used for the pipeline hazards recognition. Sometimes the +generated finite state automaton used by the pipeline hazard recognizer +is large. If we use more than one automaton and bind functional units +to the automata, the total size of the automata is usually less than +the size of the single automaton. If there is no one such +construction, only one finite state automaton is generated. + + (define_automaton AUTOMATA-NAMES) + + AUTOMATA-NAMES is a string giving names of the automata. The names +are separated by commas. All the automata should have unique names. +The automaton name is used in the constructions `define_cpu_unit' and +`define_query_cpu_unit'. + + Each processor functional unit used in the description of instruction +reservations should be described by the following construction. + + (define_cpu_unit UNIT-NAMES [AUTOMATON-NAME]) + + UNIT-NAMES is a string giving the names of the functional units +separated by commas. Don't use name `nothing', it is reserved for +other goals. + + AUTOMATON-NAME is a string giving the name of the automaton with which +the unit is bound. The automaton should be described in construction +`define_automaton'. You should give "automaton-name", if there is a +defined automaton. + + The assignment of units to automata are constrained by the uses of the +units in insn reservations. The most important constraint is: if a +unit reservation is present on a particular cycle of an alternative for +an insn reservation, then some unit from the same automaton must be +present on the same cycle for the other alternatives of the insn +reservation. The rest of the constraints are mentioned in the +description of the subsequent constructions. + + The following construction describes CPU functional units analogously +to `define_cpu_unit'. The reservation of such units can be queried for +an automaton state. The instruction scheduler never queries +reservation of functional units for given automaton state. So as a +rule, you don't need this construction. This construction could be +used for future code generation goals (e.g. to generate VLIW insn +templates). + + (define_query_cpu_unit UNIT-NAMES [AUTOMATON-NAME]) + + UNIT-NAMES is a string giving names of the functional units separated +by commas. + + AUTOMATON-NAME is a string giving the name of the automaton with which +the unit is bound. + + The following construction is the major one to describe pipeline +characteristics of an instruction. + + (define_insn_reservation INSN-NAME DEFAULT_LATENCY + CONDITION REGEXP) + + DEFAULT_LATENCY is a number giving latency time of the instruction. +There is an important difference between the old description and the +automaton based pipeline description. The latency time is used for all +dependencies when we use the old description. In the automaton based +pipeline description, the given latency time is only used for true +dependencies. The cost of anti-dependencies is always zero and the +cost of output dependencies is the difference between latency times of +the producing and consuming insns (if the difference is negative, the +cost is considered to be zero). You can always change the default +costs for any description by using the target hook +`TARGET_SCHED_ADJUST_COST' (*note Scheduling::). + + INSN-NAME is a string giving the internal name of the insn. The +internal names are used in constructions `define_bypass' and in the +automaton description file generated for debugging. The internal name +has nothing in common with the names in `define_insn'. It is a good +practice to use insn classes described in the processor manual. + + CONDITION defines what RTL insns are described by this construction. +You should remember that you will be in trouble if CONDITION for two or +more different `define_insn_reservation' constructions is TRUE for an +insn. In this case what reservation will be used for the insn is not +defined. Such cases are not checked during generation of the pipeline +hazards recognizer because in general recognizing that two conditions +may have the same value is quite difficult (especially if the conditions +contain `symbol_ref'). It is also not checked during the pipeline +hazard recognizer work because it would slow down the recognizer +considerably. + + REGEXP is a string describing the reservation of the cpu's functional +units by the instruction. The reservations are described by a regular +expression according to the following syntax: + + regexp = regexp "," oneof + | oneof + + oneof = oneof "|" allof + | allof + + allof = allof "+" repeat + | repeat + + repeat = element "*" number + | element + + element = cpu_function_unit_name + | reservation_name + | result_name + | "nothing" + | "(" regexp ")" + + * `,' is used for describing the start of the next cycle in the + reservation. + + * `|' is used for describing a reservation described by the first + regular expression *or* a reservation described by the second + regular expression *or* etc. + + * `+' is used for describing a reservation described by the first + regular expression *and* a reservation described by the second + regular expression *and* etc. + + * `*' is used for convenience and simply means a sequence in which + the regular expression are repeated NUMBER times with cycle + advancing (see `,'). + + * `cpu_function_unit_name' denotes reservation of the named + functional unit. + + * `reservation_name' -- see description of construction + `define_reservation'. + + * `nothing' denotes no unit reservations. + + Sometimes unit reservations for different insns contain common parts. +In such case, you can simplify the pipeline description by describing +the common part by the following construction + + (define_reservation RESERVATION-NAME REGEXP) + + RESERVATION-NAME is a string giving name of REGEXP. Functional unit +names and reservation names are in the same name space. So the +reservation names should be different from the functional unit names +and can not be the reserved name `nothing'. + + The following construction is used to describe exceptions in the +latency time for given instruction pair. This is so called bypasses. + + (define_bypass NUMBER OUT_INSN_NAMES IN_INSN_NAMES + [GUARD]) + + NUMBER defines when the result generated by the instructions given in +string OUT_INSN_NAMES will be ready for the instructions given in +string IN_INSN_NAMES. The instructions in the string are separated by +commas. + + GUARD is an optional string giving the name of a C function which +defines an additional guard for the bypass. The function will get the +two insns as parameters. If the function returns zero the bypass will +be ignored for this case. The additional guard is necessary to +recognize complicated bypasses, e.g. when the consumer is only an +address of insn `store' (not a stored value). + + If there are more one bypass with the same output and input insns, the +chosen bypass is the first bypass with a guard in description whose +guard function returns nonzero. If there is no such bypass, then +bypass without the guard function is chosen. + + The following five constructions are usually used to describe VLIW +processors, or more precisely, to describe a placement of small +instructions into VLIW instruction slots. They can be used for RISC +processors, too. + + (exclusion_set UNIT-NAMES UNIT-NAMES) + (presence_set UNIT-NAMES PATTERNS) + (final_presence_set UNIT-NAMES PATTERNS) + (absence_set UNIT-NAMES PATTERNS) + (final_absence_set UNIT-NAMES PATTERNS) + + UNIT-NAMES is a string giving names of functional units separated by +commas. + + PATTERNS is a string giving patterns of functional units separated by +comma. Currently pattern is one unit or units separated by +white-spaces. + + The first construction (`exclusion_set') means that each functional +unit in the first string can not be reserved simultaneously with a unit +whose name is in the second string and vice versa. For example, the +construction is useful for describing processors (e.g. some SPARC +processors) with a fully pipelined floating point functional unit which +can execute simultaneously only single floating point insns or only +double floating point insns. + + The second construction (`presence_set') means that each functional +unit in the first string can not be reserved unless at least one of +pattern of units whose names are in the second string is reserved. +This is an asymmetric relation. For example, it is useful for +description that VLIW `slot1' is reserved after `slot0' reservation. +We could describe it by the following construction + + (presence_set "slot1" "slot0") + + Or `slot1' is reserved only after `slot0' and unit `b0' reservation. +In this case we could write + + (presence_set "slot1" "slot0 b0") + + The third construction (`final_presence_set') is analogous to +`presence_set'. The difference between them is when checking is done. +When an instruction is issued in given automaton state reflecting all +current and planned unit reservations, the automaton state is changed. +The first state is a source state, the second one is a result state. +Checking for `presence_set' is done on the source state reservation, +checking for `final_presence_set' is done on the result reservation. +This construction is useful to describe a reservation which is actually +two subsequent reservations. For example, if we use + + (presence_set "slot1" "slot0") + + the following insn will be never issued (because `slot1' requires +`slot0' which is absent in the source state). + + (define_reservation "insn_and_nop" "slot0 + slot1") + + but it can be issued if we use analogous `final_presence_set'. + + The forth construction (`absence_set') means that each functional unit +in the first string can be reserved only if each pattern of units whose +names are in the second string is not reserved. This is an asymmetric +relation (actually `exclusion_set' is analogous to this one but it is +symmetric). For example it might be useful in a VLIW description to +say that `slot0' cannot be reserved after either `slot1' or `slot2' +have been reserved. This can be described as: + + (absence_set "slot0" "slot1, slot2") + + Or `slot2' can not be reserved if `slot0' and unit `b0' are reserved +or `slot1' and unit `b1' are reserved. In this case we could write + + (absence_set "slot2" "slot0 b0, slot1 b1") + + All functional units mentioned in a set should belong to the same +automaton. + + The last construction (`final_absence_set') is analogous to +`absence_set' but checking is done on the result (state) reservation. +See comments for `final_presence_set'. + + You can control the generator of the pipeline hazard recognizer with +the following construction. + + (automata_option OPTIONS) + + OPTIONS is a string giving options which affect the generated code. +Currently there are the following options: + + * "no-minimization" makes no minimization of the automaton. This is + only worth to do when we are debugging the description and need to + look more accurately at reservations of states. + + * "time" means printing time statistics about the generation of + automata. + + * "stats" means printing statistics about the generated automata + such as the number of DFA states, NDFA states and arcs. + + * "v" means a generation of the file describing the result automata. + The file has suffix `.dfa' and can be used for the description + verification and debugging. + + * "w" means a generation of warning instead of error for + non-critical errors. + + * "ndfa" makes nondeterministic finite state automata. This affects + the treatment of operator `|' in the regular expressions. The + usual treatment of the operator is to try the first alternative + and, if the reservation is not possible, the second alternative. + The nondeterministic treatment means trying all alternatives, some + of them may be rejected by reservations in the subsequent insns. + + * "progress" means output of a progress bar showing how many states + were generated so far for automaton being processed. This is + useful during debugging a DFA description. If you see too many + generated states, you could interrupt the generator of the pipeline + hazard recognizer and try to figure out a reason for generation of + the huge automaton. + + As an example, consider a superscalar RISC machine which can issue +three insns (two integer insns and one floating point insn) on the +cycle but can finish only two insns. To describe this, we define the +following functional units. + + (define_cpu_unit "i0_pipeline, i1_pipeline, f_pipeline") + (define_cpu_unit "port0, port1") + + All simple integer insns can be executed in any integer pipeline and +their result is ready in two cycles. The simple integer insns are +issued into the first pipeline unless it is reserved, otherwise they +are issued into the second pipeline. Integer division and +multiplication insns can be executed only in the second integer +pipeline and their results are ready correspondingly in 8 and 4 cycles. +The integer division is not pipelined, i.e. the subsequent integer +division insn can not be issued until the current division insn +finished. Floating point insns are fully pipelined and their results +are ready in 3 cycles. Where the result of a floating point insn is +used by an integer insn, an additional delay of one cycle is incurred. +To describe all of this we could specify + + (define_cpu_unit "div") + + (define_insn_reservation "simple" 2 (eq_attr "type" "int") + "(i0_pipeline | i1_pipeline), (port0 | port1)") + + (define_insn_reservation "mult" 4 (eq_attr "type" "mult") + "i1_pipeline, nothing*2, (port0 | port1)") + + (define_insn_reservation "div" 8 (eq_attr "type" "div") + "i1_pipeline, div*7, div + (port0 | port1)") + + (define_insn_reservation "float" 3 (eq_attr "type" "float") + "f_pipeline, nothing, (port0 | port1)) + + (define_bypass 4 "float" "simple,mult,div") + + To simplify the description we could describe the following reservation + + (define_reservation "finish" "port0|port1") + + and use it in all `define_insn_reservation' as in the following +construction + + (define_insn_reservation "simple" 2 (eq_attr "type" "int") + "(i0_pipeline | i1_pipeline), finish") + + ---------- Footnotes ---------- + + (1) However, the size of the automaton depends on processor +complexity. To limit this effect, machine descriptions can split +orthogonal parts of the machine description among several automata: but +then, since each of these must be stepped independently, this does +cause a small decrease in the algorithm's performance. + + +File: gccint.info, Node: Conditional Execution, Next: Constant Definitions, Prev: Insn Attributes, Up: Machine Desc + +16.20 Conditional Execution +=========================== + +A number of architectures provide for some form of conditional +execution, or predication. The hallmark of this feature is the ability +to nullify most of the instructions in the instruction set. When the +instruction set is large and not entirely symmetric, it can be quite +tedious to describe these forms directly in the `.md' file. An +alternative is the `define_cond_exec' template. + + (define_cond_exec + [PREDICATE-PATTERN] + "CONDITION" + "OUTPUT-TEMPLATE") + + PREDICATE-PATTERN is the condition that must be true for the insn to +be executed at runtime and should match a relational operator. One can +use `match_operator' to match several relational operators at once. +Any `match_operand' operands must have no more than one alternative. + + CONDITION is a C expression that must be true for the generated +pattern to match. + + OUTPUT-TEMPLATE is a string similar to the `define_insn' output +template (*note Output Template::), except that the `*' and `@' special +cases do not apply. This is only useful if the assembly text for the +predicate is a simple prefix to the main insn. In order to handle the +general case, there is a global variable `current_insn_predicate' that +will contain the entire predicate if the current insn is predicated, +and will otherwise be `NULL'. + + When `define_cond_exec' is used, an implicit reference to the +`predicable' instruction attribute is made. *Note Insn Attributes::. +This attribute must be boolean (i.e. have exactly two elements in its +LIST-OF-VALUES). Further, it must not be used with complex +expressions. That is, the default and all uses in the insns must be a +simple constant, not dependent on the alternative or anything else. + + For each `define_insn' for which the `predicable' attribute is true, a +new `define_insn' pattern will be generated that matches a predicated +version of the instruction. For example, + + (define_insn "addsi" + [(set (match_operand:SI 0 "register_operand" "r") + (plus:SI (match_operand:SI 1 "register_operand" "r") + (match_operand:SI 2 "register_operand" "r")))] + "TEST1" + "add %2,%1,%0") + + (define_cond_exec + [(ne (match_operand:CC 0 "register_operand" "c") + (const_int 0))] + "TEST2" + "(%0)") + +generates a new pattern + + (define_insn "" + [(cond_exec + (ne (match_operand:CC 3 "register_operand" "c") (const_int 0)) + (set (match_operand:SI 0 "register_operand" "r") + (plus:SI (match_operand:SI 1 "register_operand" "r") + (match_operand:SI 2 "register_operand" "r"))))] + "(TEST2) && (TEST1)" + "(%3) add %2,%1,%0") + + +File: gccint.info, Node: Constant Definitions, Next: Iterators, Prev: Conditional Execution, Up: Machine Desc + +16.21 Constant Definitions +========================== + +Using literal constants inside instruction patterns reduces legibility +and can be a maintenance problem. + + To overcome this problem, you may use the `define_constants' +expression. It contains a vector of name-value pairs. From that point +on, wherever any of the names appears in the MD file, it is as if the +corresponding value had been written instead. You may use +`define_constants' multiple times; each appearance adds more constants +to the table. It is an error to redefine a constant with a different +value. + + To come back to the a29k load multiple example, instead of + + (define_insn "" + [(match_parallel 0 "load_multiple_operation" + [(set (match_operand:SI 1 "gpc_reg_operand" "=r") + (match_operand:SI 2 "memory_operand" "m")) + (use (reg:SI 179)) + (clobber (reg:SI 179))])] + "" + "loadm 0,0,%1,%2") + + You could write: + + (define_constants [ + (R_BP 177) + (R_FC 178) + (R_CR 179) + (R_Q 180) + ]) + + (define_insn "" + [(match_parallel 0 "load_multiple_operation" + [(set (match_operand:SI 1 "gpc_reg_operand" "=r") + (match_operand:SI 2 "memory_operand" "m")) + (use (reg:SI R_CR)) + (clobber (reg:SI R_CR))])] + "" + "loadm 0,0,%1,%2") + + The constants that are defined with a define_constant are also output +in the insn-codes.h header file as #defines. + + You can also use the machine description file to define enumerations. +Like the constants defined by `define_constant', these enumerations are +visible to both the machine description file and the main C code. + + The syntax is as follows: + + (define_c_enum "NAME" [ + VALUE0 + VALUE1 + ... + VALUEN + ]) + + This definition causes the equivalent of the following C code to appear +in `insn-constants.h': + + enum NAME { + VALUE0 = 0, + VALUE1 = 1, + ... + VALUEN = N + }; + #define NUM_CNAME_VALUES (N + 1) + + where CNAME is the capitalized form of NAME. It also makes each +VALUEI available in the machine description file, just as if it had +been declared with: + + (define_constants [(VALUEI I)]) + + Each VALUEI is usually an upper-case identifier and usually begins +with CNAME. + + You can split the enumeration definition into as many statements as +you like. The above example is directly equivalent to: + + (define_c_enum "NAME" [VALUE0]) + (define_c_enum "NAME" [VALUE1]) + ... + (define_c_enum "NAME" [VALUEN]) + + Splitting the enumeration helps to improve the modularity of each +individual `.md' file. For example, if a port defines its +synchronization instructions in a separate `sync.md' file, it is +convenient to define all synchronization-specific enumeration values in +`sync.md' rather than in the main `.md' file. + + Some enumeration names have special significance to GCC: + +`unspecv' + If an enumeration called `unspecv' is defined, GCC will use it + when printing out `unspec_volatile' expressions. For example: + + (define_c_enum "unspecv" [ + UNSPECV_BLOCKAGE + ]) + + causes GCC to print `(unspec_volatile ... 0)' as: + + (unspec_volatile ... UNSPECV_BLOCKAGE) + +`unspec' + If an enumeration called `unspec' is defined, GCC will use it when + printing out `unspec' expressions. GCC will also use it when + printing out `unspec_volatile' expressions unless an `unspecv' + enumeration is also defined. You can therefore decide whether to + keep separate enumerations for volatile and non-volatile + expressions or whether to use the same enumeration for both. + + Another way of defining an enumeration is to use `define_enum': + + (define_enum "NAME" [ + VALUE0 + VALUE1 + ... + VALUEN + ]) + + This directive implies: + + (define_c_enum "NAME" [ + CNAME_CVALUE0 + CNAME_CVALUE1 + ... + CNAME_CVALUEN + ]) + + where CVALUEI is the capitalized form of VALUEI. However, unlike +`define_c_enum', the enumerations defined by `define_enum' can be used +in attribute specifications (*note define_enum_attr::). + + +File: gccint.info, Node: Iterators, Prev: Constant Definitions, Up: Machine Desc + +16.22 Iterators +=============== + +Ports often need to define similar patterns for more than one machine +mode or for more than one rtx code. GCC provides some simple iterator +facilities to make this process easier. + +* Menu: + +* Mode Iterators:: Generating variations of patterns for different modes. +* Code Iterators:: Doing the same for codes. + + +File: gccint.info, Node: Mode Iterators, Next: Code Iterators, Up: Iterators + +16.22.1 Mode Iterators +---------------------- + +Ports often need to define similar patterns for two or more different +modes. For example: + + * If a processor has hardware support for both single and double + floating-point arithmetic, the `SFmode' patterns tend to be very + similar to the `DFmode' ones. + + * If a port uses `SImode' pointers in one configuration and `DImode' + pointers in another, it will usually have very similar `SImode' + and `DImode' patterns for manipulating pointers. + + Mode iterators allow several patterns to be instantiated from one +`.md' file template. They can be used with any type of rtx-based +construct, such as a `define_insn', `define_split', or +`define_peephole2'. + +* Menu: + +* Defining Mode Iterators:: Defining a new mode iterator. +* Substitutions:: Combining mode iterators with substitutions +* Examples:: Examples + + +File: gccint.info, Node: Defining Mode Iterators, Next: Substitutions, Up: Mode Iterators + +16.22.1.1 Defining Mode Iterators +................................. + +The syntax for defining a mode iterator is: + + (define_mode_iterator NAME [(MODE1 "COND1") ... (MODEN "CONDN")]) + + This allows subsequent `.md' file constructs to use the mode suffix +`:NAME'. Every construct that does so will be expanded N times, once +with every use of `:NAME' replaced by `:MODE1', once with every use +replaced by `:MODE2', and so on. In the expansion for a particular +MODEI, every C condition will also require that CONDI be true. + + For example: + + (define_mode_iterator P [(SI "Pmode == SImode") (DI "Pmode == DImode")]) + + defines a new mode suffix `:P'. Every construct that uses `:P' will +be expanded twice, once with every `:P' replaced by `:SI' and once with +every `:P' replaced by `:DI'. The `:SI' version will only apply if +`Pmode == SImode' and the `:DI' version will only apply if `Pmode == +DImode'. + + As with other `.md' conditions, an empty string is treated as "always +true". `(MODE "")' can also be abbreviated to `MODE'. For example: + + (define_mode_iterator GPR [SI (DI "TARGET_64BIT")]) + + means that the `:DI' expansion only applies if `TARGET_64BIT' but that +the `:SI' expansion has no such constraint. + + Iterators are applied in the order they are defined. This can be +significant if two iterators are used in a construct that requires +substitutions. *Note Substitutions::. + + +File: gccint.info, Node: Substitutions, Next: Examples, Prev: Defining Mode Iterators, Up: Mode Iterators + +16.22.1.2 Substitution in Mode Iterators +........................................ + +If an `.md' file construct uses mode iterators, each version of the +construct will often need slightly different strings or modes. For +example: + + * When a `define_expand' defines several `addM3' patterns (*note + Standard Names::), each expander will need to use the appropriate + mode name for M. + + * When a `define_insn' defines several instruction patterns, each + instruction will often use a different assembler mnemonic. + + * When a `define_insn' requires operands with different modes, using + an iterator for one of the operand modes usually requires a + specific mode for the other operand(s). + + GCC supports such variations through a system of "mode attributes". +There are two standard attributes: `mode', which is the name of the +mode in lower case, and `MODE', which is the same thing in upper case. +You can define other attributes using: + + (define_mode_attr NAME [(MODE1 "VALUE1") ... (MODEN "VALUEN")]) + + where NAME is the name of the attribute and VALUEI is the value +associated with MODEI. + + When GCC replaces some :ITERATOR with :MODE, it will scan each string +and mode in the pattern for sequences of the form `<ITERATOR:ATTR>', +where ATTR is the name of a mode attribute. If the attribute is +defined for MODE, the whole `<...>' sequence will be replaced by the +appropriate attribute value. + + For example, suppose an `.md' file has: + + (define_mode_iterator P [(SI "Pmode == SImode") (DI "Pmode == DImode")]) + (define_mode_attr load [(SI "lw") (DI "ld")]) + + If one of the patterns that uses `:P' contains the string +`"<P:load>\t%0,%1"', the `SI' version of that pattern will use +`"lw\t%0,%1"' and the `DI' version will use `"ld\t%0,%1"'. + + Here is an example of using an attribute for a mode: + + (define_mode_iterator LONG [SI DI]) + (define_mode_attr SHORT [(SI "HI") (DI "SI")]) + (define_insn ... + (sign_extend:LONG (match_operand:<LONG:SHORT> ...)) ...) + + The `ITERATOR:' prefix may be omitted, in which case the substitution +will be attempted for every iterator expansion. + + +File: gccint.info, Node: Examples, Prev: Substitutions, Up: Mode Iterators + +16.22.1.3 Mode Iterator Examples +................................ + +Here is an example from the MIPS port. It defines the following modes +and attributes (among others): + + (define_mode_iterator GPR [SI (DI "TARGET_64BIT")]) + (define_mode_attr d [(SI "") (DI "d")]) + + and uses the following template to define both `subsi3' and `subdi3': + + (define_insn "sub<mode>3" + [(set (match_operand:GPR 0 "register_operand" "=d") + (minus:GPR (match_operand:GPR 1 "register_operand" "d") + (match_operand:GPR 2 "register_operand" "d")))] + "" + "<d>subu\t%0,%1,%2" + [(set_attr "type" "arith") + (set_attr "mode" "<MODE>")]) + + This is exactly equivalent to: + + (define_insn "subsi3" + [(set (match_operand:SI 0 "register_operand" "=d") + (minus:SI (match_operand:SI 1 "register_operand" "d") + (match_operand:SI 2 "register_operand" "d")))] + "" + "subu\t%0,%1,%2" + [(set_attr "type" "arith") + (set_attr "mode" "SI")]) + + (define_insn "subdi3" + [(set (match_operand:DI 0 "register_operand" "=d") + (minus:DI (match_operand:DI 1 "register_operand" "d") + (match_operand:DI 2 "register_operand" "d")))] + "" + "dsubu\t%0,%1,%2" + [(set_attr "type" "arith") + (set_attr "mode" "DI")]) + + +File: gccint.info, Node: Code Iterators, Prev: Mode Iterators, Up: Iterators + +16.22.2 Code Iterators +---------------------- + +Code iterators operate in a similar way to mode iterators. *Note Mode +Iterators::. + + The construct: + + (define_code_iterator NAME [(CODE1 "COND1") ... (CODEN "CONDN")]) + + defines a pseudo rtx code NAME that can be instantiated as CODEI if +condition CONDI is true. Each CODEI must have the same rtx format. +*Note RTL Classes::. + + As with mode iterators, each pattern that uses NAME will be expanded N +times, once with all uses of NAME replaced by CODE1, once with all uses +replaced by CODE2, and so on. *Note Defining Mode Iterators::. + + It is possible to define attributes for codes as well as for modes. +There are two standard code attributes: `code', the name of the code in +lower case, and `CODE', the name of the code in upper case. Other +attributes are defined using: + + (define_code_attr NAME [(CODE1 "VALUE1") ... (CODEN "VALUEN")]) + + Here's an example of code iterators in action, taken from the MIPS +port: + + (define_code_iterator any_cond [unordered ordered unlt unge uneq ltgt unle ungt + eq ne gt ge lt le gtu geu ltu leu]) + + (define_expand "b<code>" + [(set (pc) + (if_then_else (any_cond:CC (cc0) + (const_int 0)) + (label_ref (match_operand 0 "")) + (pc)))] + "" + { + gen_conditional_branch (operands, <CODE>); + DONE; + }) + + This is equivalent to: + + (define_expand "bunordered" + [(set (pc) + (if_then_else (unordered:CC (cc0) + (const_int 0)) + (label_ref (match_operand 0 "")) + (pc)))] + "" + { + gen_conditional_branch (operands, UNORDERED); + DONE; + }) + + (define_expand "bordered" + [(set (pc) + (if_then_else (ordered:CC (cc0) + (const_int 0)) + (label_ref (match_operand 0 "")) + (pc)))] + "" + { + gen_conditional_branch (operands, ORDERED); + DONE; + }) + + ... + + +File: gccint.info, Node: Target Macros, Next: Host Config, Prev: Machine Desc, Up: Top + +17 Target Description Macros and Functions +****************************************** + +In addition to the file `MACHINE.md', a machine description includes a +C header file conventionally given the name `MACHINE.h' and a C source +file named `MACHINE.c'. The header file defines numerous macros that +convey the information about the target machine that does not fit into +the scheme of the `.md' file. The file `tm.h' should be a link to +`MACHINE.h'. The header file `config.h' includes `tm.h' and most +compiler source files include `config.h'. The source file defines a +variable `targetm', which is a structure containing pointers to +functions and data relating to the target machine. `MACHINE.c' should +also contain their definitions, if they are not defined elsewhere in +GCC, and other functions called through the macros defined in the `.h' +file. + +* Menu: + +* Target Structure:: The `targetm' variable. +* Driver:: Controlling how the driver runs the compilation passes. +* Run-time Target:: Defining `-m' options like `-m68000' and `-m68020'. +* Per-Function Data:: Defining data structures for per-function information. +* Storage Layout:: Defining sizes and alignments of data. +* Type Layout:: Defining sizes and properties of basic user data types. +* Registers:: Naming and describing the hardware registers. +* Register Classes:: Defining the classes of hardware registers. +* Old Constraints:: The old way to define machine-specific constraints. +* Stack and Calling:: Defining which way the stack grows and by how much. +* Varargs:: Defining the varargs macros. +* Trampolines:: Code set up at run time to enter a nested function. +* Library Calls:: Controlling how library routines are implicitly called. +* Addressing Modes:: Defining addressing modes valid for memory operands. +* Anchored Addresses:: Defining how `-fsection-anchors' should work. +* Condition Code:: Defining how insns update the condition code. +* Costs:: Defining relative costs of different operations. +* Scheduling:: Adjusting the behavior of the instruction scheduler. +* Sections:: Dividing storage into text, data, and other sections. +* PIC:: Macros for position independent code. +* Assembler Format:: Defining how to write insns and pseudo-ops to output. +* Debugging Info:: Defining the format of debugging output. +* Floating Point:: Handling floating point for cross-compilers. +* Mode Switching:: Insertion of mode-switching instructions. +* Target Attributes:: Defining target-specific uses of `__attribute__'. +* Emulated TLS:: Emulated TLS support. +* MIPS Coprocessors:: MIPS coprocessor support and how to customize it. +* PCH Target:: Validity checking for precompiled headers. +* C++ ABI:: Controlling C++ ABI changes. +* Named Address Spaces:: Adding support for named address spaces +* Misc:: Everything else. + + +File: gccint.info, Node: Target Structure, Next: Driver, Up: Target Macros + +17.1 The Global `targetm' Variable +================================== + + -- Variable: struct gcc_target targetm + The target `.c' file must define the global `targetm' variable + which contains pointers to functions and data relating to the + target machine. The variable is declared in `target.h'; + `target-def.h' defines the macro `TARGET_INITIALIZER' which is + used to initialize the variable, and macros for the default + initializers for elements of the structure. The `.c' file should + override those macros for which the default definition is + inappropriate. For example: + #include "target.h" + #include "target-def.h" + + /* Initialize the GCC target structure. */ + + #undef TARGET_COMP_TYPE_ATTRIBUTES + #define TARGET_COMP_TYPE_ATTRIBUTES MACHINE_comp_type_attributes + + struct gcc_target targetm = TARGET_INITIALIZER; + +Where a macro should be defined in the `.c' file in this manner to form +part of the `targetm' structure, it is documented below as a "Target +Hook" with a prototype. Many macros will change in future from being +defined in the `.h' file to being part of the `targetm' structure. + + +File: gccint.info, Node: Driver, Next: Run-time Target, Prev: Target Structure, Up: Target Macros + +17.2 Controlling the Compilation Driver, `gcc' +============================================== + +You can control the compilation driver. + + -- Macro: DRIVER_SELF_SPECS + A list of specs for the driver itself. It should be a suitable + initializer for an array of strings, with no surrounding braces. + + The driver applies these specs to its own command line between + loading default `specs' files (but not command-line specified + ones) and choosing the multilib directory or running any + subcommands. It applies them in the order given, so each spec can + depend on the options added by earlier ones. It is also possible + to remove options using `%<OPTION' in the usual way. + + This macro can be useful when a port has several interdependent + target options. It provides a way of standardizing the command + line so that the other specs are easier to write. + + Do not define this macro if it does not need to do anything. + + -- Macro: OPTION_DEFAULT_SPECS + A list of specs used to support configure-time default options + (i.e. `--with' options) in the driver. It should be a suitable + initializer for an array of structures, each containing two + strings, without the outermost pair of surrounding braces. + + The first item in the pair is the name of the default. This must + match the code in `config.gcc' for the target. The second item is + a spec to apply if a default with this name was specified. The + string `%(VALUE)' in the spec will be replaced by the value of the + default everywhere it occurs. + + The driver will apply these specs to its own command line between + loading default `specs' files and processing `DRIVER_SELF_SPECS', + using the same mechanism as `DRIVER_SELF_SPECS'. + + Do not define this macro if it does not need to do anything. + + -- Macro: CPP_SPEC + A C string constant that tells the GCC driver program options to + pass to CPP. It can also specify how to translate options you + give to GCC into options for GCC to pass to the CPP. + + Do not define this macro if it does not need to do anything. + + -- Macro: CPLUSPLUS_CPP_SPEC + This macro is just like `CPP_SPEC', but is used for C++, rather + than C. If you do not define this macro, then the value of + `CPP_SPEC' (if any) will be used instead. + + -- Macro: CC1_SPEC + A C string constant that tells the GCC driver program options to + pass to `cc1', `cc1plus', `f771', and the other language front + ends. It can also specify how to translate options you give to + GCC into options for GCC to pass to front ends. + + Do not define this macro if it does not need to do anything. + + -- Macro: CC1PLUS_SPEC + A C string constant that tells the GCC driver program options to + pass to `cc1plus'. It can also specify how to translate options + you give to GCC into options for GCC to pass to the `cc1plus'. + + Do not define this macro if it does not need to do anything. Note + that everything defined in CC1_SPEC is already passed to `cc1plus' + so there is no need to duplicate the contents of CC1_SPEC in + CC1PLUS_SPEC. + + -- Macro: ASM_SPEC + A C string constant that tells the GCC driver program options to + pass to the assembler. It can also specify how to translate + options you give to GCC into options for GCC to pass to the + assembler. See the file `sun3.h' for an example of this. + + Do not define this macro if it does not need to do anything. + + -- Macro: ASM_FINAL_SPEC + A C string constant that tells the GCC driver program how to run + any programs which cleanup after the normal assembler. Normally, + this is not needed. See the file `mips.h' for an example of this. + + Do not define this macro if it does not need to do anything. + + -- Macro: AS_NEEDS_DASH_FOR_PIPED_INPUT + Define this macro, with no value, if the driver should give the + assembler an argument consisting of a single dash, `-', to + instruct it to read from its standard input (which will be a pipe + connected to the output of the compiler proper). This argument is + given after any `-o' option specifying the name of the output file. + + If you do not define this macro, the assembler is assumed to read + its standard input if given no non-option arguments. If your + assembler cannot read standard input at all, use a `%{pipe:%e}' + construct; see `mips.h' for instance. + + -- Macro: LINK_SPEC + A C string constant that tells the GCC driver program options to + pass to the linker. It can also specify how to translate options + you give to GCC into options for GCC to pass to the linker. + + Do not define this macro if it does not need to do anything. + + -- Macro: LIB_SPEC + Another C string constant used much like `LINK_SPEC'. The + difference between the two is that `LIB_SPEC' is used at the end + of the command given to the linker. + + If this macro is not defined, a default is provided that loads the + standard C library from the usual place. See `gcc.c'. + + -- Macro: LIBGCC_SPEC + Another C string constant that tells the GCC driver program how + and when to place a reference to `libgcc.a' into the linker + command line. This constant is placed both before and after the + value of `LIB_SPEC'. + + If this macro is not defined, the GCC driver provides a default + that passes the string `-lgcc' to the linker. + + -- Macro: REAL_LIBGCC_SPEC + By default, if `ENABLE_SHARED_LIBGCC' is defined, the + `LIBGCC_SPEC' is not directly used by the driver program but is + instead modified to refer to different versions of `libgcc.a' + depending on the values of the command line flags `-static', + `-shared', `-static-libgcc', and `-shared-libgcc'. On targets + where these modifications are inappropriate, define + `REAL_LIBGCC_SPEC' instead. `REAL_LIBGCC_SPEC' tells the driver + how to place a reference to `libgcc' on the link command line, + but, unlike `LIBGCC_SPEC', it is used unmodified. + + -- Macro: USE_LD_AS_NEEDED + A macro that controls the modifications to `LIBGCC_SPEC' mentioned + in `REAL_LIBGCC_SPEC'. If nonzero, a spec will be generated that + uses -as-needed and the shared libgcc in place of the static + exception handler library, when linking without any of `-static', + `-static-libgcc', or `-shared-libgcc'. + + -- Macro: LINK_EH_SPEC + If defined, this C string constant is added to `LINK_SPEC'. When + `USE_LD_AS_NEEDED' is zero or undefined, it also affects the + modifications to `LIBGCC_SPEC' mentioned in `REAL_LIBGCC_SPEC'. + + -- Macro: STARTFILE_SPEC + Another C string constant used much like `LINK_SPEC'. The + difference between the two is that `STARTFILE_SPEC' is used at the + very beginning of the command given to the linker. + + If this macro is not defined, a default is provided that loads the + standard C startup file from the usual place. See `gcc.c'. + + -- Macro: ENDFILE_SPEC + Another C string constant used much like `LINK_SPEC'. The + difference between the two is that `ENDFILE_SPEC' is used at the + very end of the command given to the linker. + + Do not define this macro if it does not need to do anything. + + -- Macro: THREAD_MODEL_SPEC + GCC `-v' will print the thread model GCC was configured to use. + However, this doesn't work on platforms that are multilibbed on + thread models, such as AIX 4.3. On such platforms, define + `THREAD_MODEL_SPEC' such that it evaluates to a string without + blanks that names one of the recognized thread models. `%*', the + default value of this macro, will expand to the value of + `thread_file' set in `config.gcc'. + + -- Macro: SYSROOT_SUFFIX_SPEC + Define this macro to add a suffix to the target sysroot when GCC is + configured with a sysroot. This will cause GCC to search for + usr/lib, et al, within sysroot+suffix. + + -- Macro: SYSROOT_HEADERS_SUFFIX_SPEC + Define this macro to add a headers_suffix to the target sysroot + when GCC is configured with a sysroot. This will cause GCC to + pass the updated sysroot+headers_suffix to CPP, causing it to + search for usr/include, et al, within sysroot+headers_suffix. + + -- Macro: EXTRA_SPECS + Define this macro to provide additional specifications to put in + the `specs' file that can be used in various specifications like + `CC1_SPEC'. + + The definition should be an initializer for an array of structures, + containing a string constant, that defines the specification name, + and a string constant that provides the specification. + + Do not define this macro if it does not need to do anything. + + `EXTRA_SPECS' is useful when an architecture contains several + related targets, which have various `..._SPECS' which are similar + to each other, and the maintainer would like one central place to + keep these definitions. + + For example, the PowerPC System V.4 targets use `EXTRA_SPECS' to + define either `_CALL_SYSV' when the System V calling sequence is + used or `_CALL_AIX' when the older AIX-based calling sequence is + used. + + The `config/rs6000/rs6000.h' target file defines: + + #define EXTRA_SPECS \ + { "cpp_sysv_default", CPP_SYSV_DEFAULT }, + + #define CPP_SYS_DEFAULT "" + + The `config/rs6000/sysv.h' target file defines: + #undef CPP_SPEC + #define CPP_SPEC \ + "%{posix: -D_POSIX_SOURCE } \ + %{mcall-sysv: -D_CALL_SYSV } \ + %{!mcall-sysv: %(cpp_sysv_default) } \ + %{msoft-float: -D_SOFT_FLOAT} %{mcpu=403: -D_SOFT_FLOAT}" + + #undef CPP_SYSV_DEFAULT + #define CPP_SYSV_DEFAULT "-D_CALL_SYSV" + + while the `config/rs6000/eabiaix.h' target file defines + `CPP_SYSV_DEFAULT' as: + + #undef CPP_SYSV_DEFAULT + #define CPP_SYSV_DEFAULT "-D_CALL_AIX" + + -- Macro: LINK_LIBGCC_SPECIAL_1 + Define this macro if the driver program should find the library + `libgcc.a'. If you do not define this macro, the driver program + will pass the argument `-lgcc' to tell the linker to do the search. + + -- Macro: LINK_GCC_C_SEQUENCE_SPEC + The sequence in which libgcc and libc are specified to the linker. + By default this is `%G %L %G'. + + -- Macro: LINK_COMMAND_SPEC + A C string constant giving the complete command line need to + execute the linker. When you do this, you will need to update + your port each time a change is made to the link command line + within `gcc.c'. Therefore, define this macro only if you need to + completely redefine the command line for invoking the linker and + there is no other way to accomplish the effect you need. + Overriding this macro may be avoidable by overriding + `LINK_GCC_C_SEQUENCE_SPEC' instead. + + -- Macro: LINK_ELIMINATE_DUPLICATE_LDIRECTORIES + A nonzero value causes `collect2' to remove duplicate + `-LDIRECTORY' search directories from linking commands. Do not + give it a nonzero value if removing duplicate search directories + changes the linker's semantics. + + -- Macro: MULTILIB_DEFAULTS + Define this macro as a C expression for the initializer of an + array of string to tell the driver program which options are + defaults for this target and thus do not need to be handled + specially when using `MULTILIB_OPTIONS'. + + Do not define this macro if `MULTILIB_OPTIONS' is not defined in + the target makefile fragment or if none of the options listed in + `MULTILIB_OPTIONS' are set by default. *Note Target Fragment::. + + -- Macro: RELATIVE_PREFIX_NOT_LINKDIR + Define this macro to tell `gcc' that it should only translate a + `-B' prefix into a `-L' linker option if the prefix indicates an + absolute file name. + + -- Macro: MD_EXEC_PREFIX + If defined, this macro is an additional prefix to try after + `STANDARD_EXEC_PREFIX'. `MD_EXEC_PREFIX' is not searched when the + compiler is built as a cross compiler. If you define + `MD_EXEC_PREFIX', then be sure to add it to the list of + directories used to find the assembler in `configure.in'. + + -- Macro: STANDARD_STARTFILE_PREFIX + Define this macro as a C string constant if you wish to override + the standard choice of `libdir' as the default prefix to try when + searching for startup files such as `crt0.o'. + `STANDARD_STARTFILE_PREFIX' is not searched when the compiler is + built as a cross compiler. + + -- Macro: STANDARD_STARTFILE_PREFIX_1 + Define this macro as a C string constant if you wish to override + the standard choice of `/lib' as a prefix to try after the default + prefix when searching for startup files such as `crt0.o'. + `STANDARD_STARTFILE_PREFIX_1' is not searched when the compiler is + built as a cross compiler. + + -- Macro: STANDARD_STARTFILE_PREFIX_2 + Define this macro as a C string constant if you wish to override + the standard choice of `/lib' as yet another prefix to try after + the default prefix when searching for startup files such as + `crt0.o'. `STANDARD_STARTFILE_PREFIX_2' is not searched when the + compiler is built as a cross compiler. + + -- Macro: MD_STARTFILE_PREFIX + If defined, this macro supplies an additional prefix to try after + the standard prefixes. `MD_EXEC_PREFIX' is not searched when the + compiler is built as a cross compiler. + + -- Macro: MD_STARTFILE_PREFIX_1 + If defined, this macro supplies yet another prefix to try after the + standard prefixes. It is not searched when the compiler is built + as a cross compiler. + + -- Macro: INIT_ENVIRONMENT + Define this macro as a C string constant if you wish to set + environment variables for programs called by the driver, such as + the assembler and loader. The driver passes the value of this + macro to `putenv' to initialize the necessary environment + variables. + + -- Macro: LOCAL_INCLUDE_DIR + Define this macro as a C string constant if you wish to override + the standard choice of `/usr/local/include' as the default prefix + to try when searching for local header files. `LOCAL_INCLUDE_DIR' + comes before `SYSTEM_INCLUDE_DIR' in the search order. + + Cross compilers do not search either `/usr/local/include' or its + replacement. + + -- Macro: SYSTEM_INCLUDE_DIR + Define this macro as a C string constant if you wish to specify a + system-specific directory to search for header files before the + standard directory. `SYSTEM_INCLUDE_DIR' comes before + `STANDARD_INCLUDE_DIR' in the search order. + + Cross compilers do not use this macro and do not search the + directory specified. + + -- Macro: STANDARD_INCLUDE_DIR + Define this macro as a C string constant if you wish to override + the standard choice of `/usr/include' as the default prefix to try + when searching for header files. + + Cross compilers ignore this macro and do not search either + `/usr/include' or its replacement. + + -- Macro: STANDARD_INCLUDE_COMPONENT + The "component" corresponding to `STANDARD_INCLUDE_DIR'. See + `INCLUDE_DEFAULTS', below, for the description of components. If + you do not define this macro, no component is used. + + -- Macro: INCLUDE_DEFAULTS + Define this macro if you wish to override the entire default + search path for include files. For a native compiler, the default + search path usually consists of `GCC_INCLUDE_DIR', + `LOCAL_INCLUDE_DIR', `SYSTEM_INCLUDE_DIR', + `GPLUSPLUS_INCLUDE_DIR', and `STANDARD_INCLUDE_DIR'. In addition, + `GPLUSPLUS_INCLUDE_DIR' and `GCC_INCLUDE_DIR' are defined + automatically by `Makefile', and specify private search areas for + GCC. The directory `GPLUSPLUS_INCLUDE_DIR' is used only for C++ + programs. + + The definition should be an initializer for an array of structures. + Each array element should have four elements: the directory name (a + string constant), the component name (also a string constant), a + flag for C++-only directories, and a flag showing that the + includes in the directory don't need to be wrapped in `extern `C'' + when compiling C++. Mark the end of the array with a null element. + + The component name denotes what GNU package the include file is + part of, if any, in all uppercase letters. For example, it might + be `GCC' or `BINUTILS'. If the package is part of a + vendor-supplied operating system, code the component name as `0'. + + For example, here is the definition used for VAX/VMS: + + #define INCLUDE_DEFAULTS \ + { \ + { "GNU_GXX_INCLUDE:", "G++", 1, 1}, \ + { "GNU_CC_INCLUDE:", "GCC", 0, 0}, \ + { "SYS$SYSROOT:[SYSLIB.]", 0, 0, 0}, \ + { ".", 0, 0, 0}, \ + { 0, 0, 0, 0} \ + } + + Here is the order of prefixes tried for exec files: + + 1. Any prefixes specified by the user with `-B'. + + 2. The environment variable `GCC_EXEC_PREFIX' or, if `GCC_EXEC_PREFIX' + is not set and the compiler has not been installed in the + configure-time PREFIX, the location in which the compiler has + actually been installed. + + 3. The directories specified by the environment variable + `COMPILER_PATH'. + + 4. The macro `STANDARD_EXEC_PREFIX', if the compiler has been + installed in the configured-time PREFIX. + + 5. The location `/usr/libexec/gcc/', but only if this is a native + compiler. + + 6. The location `/usr/lib/gcc/', but only if this is a native + compiler. + + 7. The macro `MD_EXEC_PREFIX', if defined, but only if this is a + native compiler. + + Here is the order of prefixes tried for startfiles: + + 1. Any prefixes specified by the user with `-B'. + + 2. The environment variable `GCC_EXEC_PREFIX' or its automatically + determined value based on the installed toolchain location. + + 3. The directories specified by the environment variable + `LIBRARY_PATH' (or port-specific name; native only, cross + compilers do not use this). + + 4. The macro `STANDARD_EXEC_PREFIX', but only if the toolchain is + installed in the configured PREFIX or this is a native compiler. + + 5. The location `/usr/lib/gcc/', but only if this is a native + compiler. + + 6. The macro `MD_EXEC_PREFIX', if defined, but only if this is a + native compiler. + + 7. The macro `MD_STARTFILE_PREFIX', if defined, but only if this is a + native compiler, or we have a target system root. + + 8. The macro `MD_STARTFILE_PREFIX_1', if defined, but only if this is + a native compiler, or we have a target system root. + + 9. The macro `STANDARD_STARTFILE_PREFIX', with any sysroot + modifications. If this path is relative it will be prefixed by + `GCC_EXEC_PREFIX' and the machine suffix or `STANDARD_EXEC_PREFIX' + and the machine suffix. + + 10. The macro `STANDARD_STARTFILE_PREFIX_1', but only if this is a + native compiler, or we have a target system root. The default for + this macro is `/lib/'. + + 11. The macro `STANDARD_STARTFILE_PREFIX_2', but only if this is a + native compiler, or we have a target system root. The default for + this macro is `/usr/lib/'. + + +File: gccint.info, Node: Run-time Target, Next: Per-Function Data, Prev: Driver, Up: Target Macros + +17.3 Run-time Target Specification +================================== + +Here are run-time target specifications. + + -- Macro: TARGET_CPU_CPP_BUILTINS () + This function-like macro expands to a block of code that defines + built-in preprocessor macros and assertions for the target CPU, + using the functions `builtin_define', `builtin_define_std' and + `builtin_assert'. When the front end calls this macro it provides + a trailing semicolon, and since it has finished command line + option processing your code can use those results freely. + + `builtin_assert' takes a string in the form you pass to the + command-line option `-A', such as `cpu=mips', and creates the + assertion. `builtin_define' takes a string in the form accepted + by option `-D' and unconditionally defines the macro. + + `builtin_define_std' takes a string representing the name of an + object-like macro. If it doesn't lie in the user's namespace, + `builtin_define_std' defines it unconditionally. Otherwise, it + defines a version with two leading underscores, and another version + with two leading and trailing underscores, and defines the original + only if an ISO standard was not requested on the command line. For + example, passing `unix' defines `__unix', `__unix__' and possibly + `unix'; passing `_mips' defines `__mips', `__mips__' and possibly + `_mips', and passing `_ABI64' defines only `_ABI64'. + + You can also test for the C dialect being compiled. The variable + `c_language' is set to one of `clk_c', `clk_cplusplus' or + `clk_objective_c'. Note that if we are preprocessing assembler, + this variable will be `clk_c' but the function-like macro + `preprocessing_asm_p()' will return true, so you might want to + check for that first. If you need to check for strict ANSI, the + variable `flag_iso' can be used. The function-like macro + `preprocessing_trad_p()' can be used to check for traditional + preprocessing. + + -- Macro: TARGET_OS_CPP_BUILTINS () + Similarly to `TARGET_CPU_CPP_BUILTINS' but this macro is optional + and is used for the target operating system instead. + + -- Macro: TARGET_OBJFMT_CPP_BUILTINS () + Similarly to `TARGET_CPU_CPP_BUILTINS' but this macro is optional + and is used for the target object format. `elfos.h' uses this + macro to define `__ELF__', so you probably do not need to define + it yourself. + + -- Variable: extern int target_flags + This variable is declared in `options.h', which is included before + any target-specific headers. + + -- Target Hook: int TARGET_DEFAULT_TARGET_FLAGS + This variable specifies the initial value of `target_flags'. Its + default setting is 0. + + -- Target Hook: bool TARGET_HANDLE_OPTION (size_t CODE, const char + *ARG, int VALUE) + This hook is called whenever the user specifies one of the + target-specific options described by the `.opt' definition files + (*note Options::). It has the opportunity to do some + option-specific processing and should return true if the option is + valid. The default definition does nothing but return true. + + CODE specifies the `OPT_NAME' enumeration value associated with + the selected option; NAME is just a rendering of the option name + in which non-alphanumeric characters are replaced by underscores. + ARG specifies the string argument and is null if no argument was + given. If the option is flagged as a `UInteger' (*note Option + properties::), VALUE is the numeric value of the argument. + Otherwise VALUE is 1 if the positive form of the option was used + and 0 if the "no-" form was. + + -- Target Hook: bool TARGET_HANDLE_C_OPTION (size_t CODE, const char + *ARG, int VALUE) + This target hook is called whenever the user specifies one of the + target-specific C language family options described by the `.opt' + definition files(*note Options::). It has the opportunity to do + some option-specific processing and should return true if the + option is valid. The arguments are like for + `TARGET_HANDLE_OPTION'. The default definition does nothing but + return false. + + In general, you should use `TARGET_HANDLE_OPTION' to handle + options. However, if processing an option requires routines that + are only available in the C (and related language) front ends, + then you should use `TARGET_HANDLE_C_OPTION' instead. + + -- Target Hook: tree TARGET_OBJC_CONSTRUCT_STRING_OBJECT (tree STRING) + Targets may provide a string object type that can be used within + and between C, C++ and their respective Objective-C dialects. A + string object might, for example, embed encoding and length + information. These objects are considered opaque to the compiler + and handled as references. An ideal implementation makes the + composition of the string object match that of the Objective-C + `NSString' (`NXString' for GNUStep), allowing efficient + interworking between C-only and Objective-C code. If a target + implements string objects then this hook should return a reference + to such an object constructed from the normal `C' string + representation provided in STRING. At present, the hook is used by + Objective-C only, to obtain a common-format string object when the + target provides one. + + -- Target Hook: bool TARGET_STRING_OBJECT_REF_TYPE_P (const_tree + STRINGREF) + If a target implements string objects then this hook should return + `true' if STRINGREF is a valid reference to such an object. + + -- Target Hook: void TARGET_CHECK_STRING_OBJECT_FORMAT_ARG (tree + FORMAT_ARG, tree ARGS_LIST) + If a target implements string objects then this hook should should + provide a facility to check the function arguments in ARGS_LIST + against the format specifiers in FORMAT_ARG where the type of + FORMAT_ARG is one recognized as a valid string reference type. + + -- Macro: TARGET_VERSION + This macro is a C statement to print on `stderr' a string + describing the particular machine description choice. Every + machine description should define `TARGET_VERSION'. For example: + + #ifdef MOTOROLA + #define TARGET_VERSION \ + fprintf (stderr, " (68k, Motorola syntax)"); + #else + #define TARGET_VERSION \ + fprintf (stderr, " (68k, MIT syntax)"); + #endif + + -- Target Hook: void TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE (void) + This target function is similar to the hook + `TARGET_OPTION_OVERRIDE' but is called when the optimize level is + changed via an attribute or pragma or when it is reset at the end + of the code affected by the attribute or pragma. It is not called + at the beginning of compilation when `TARGET_OPTION_OVERRIDE' is + called so if you want to perform these actions then, you should + have `TARGET_OPTION_OVERRIDE' call + `TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE'. + + -- Macro: C_COMMON_OVERRIDE_OPTIONS + This is similar to the `TARGET_OPTION_OVERRIDE' hook but is only + used in the C language frontends (C, Objective-C, C++, + Objective-C++) and so can be used to alter option flag variables + which only exist in those frontends. + + -- Target Hook: const struct default_options * +TARGET_OPTION_OPTIMIZATION_TABLE + Some machines may desire to change what optimizations are + performed for various optimization levels. This variable, if + defined, describes options to enable at particular sets of + optimization levels. These options are processed once just after + the optimization level is determined and before the remainder of + the command options have been parsed, so may be overridden by other + options passed explicitly. + + This processing is run once at program startup and when the + optimization options are changed via `#pragma GCC optimize' or by + using the `optimize' attribute. + + -- Target Hook: void TARGET_OPTION_INIT_STRUCT (struct gcc_options + *OPTS) + Set target-dependent initial values of fields in OPTS. + + -- Target Hook: void TARGET_OPTION_DEFAULT_PARAMS (void) + Set target-dependent default values for `--param' settings, using + calls to `set_default_param_value'. + + -- Target Hook: void TARGET_HELP (void) + This hook is called in response to the user invoking + `--target-help' on the command line. It gives the target a chance + to display extra information on the target specific command line + options found in its `.opt' file. + + -- Macro: SWITCHABLE_TARGET + Some targets need to switch between substantially different + subtargets during compilation. For example, the MIPS target has + one subtarget for the traditional MIPS architecture and another + for MIPS16. Source code can switch between these two + subarchitectures using the `mips16' and `nomips16' attributes. + + Such subtargets can differ in things like the set of available + registers, the set of available instructions, the costs of various + operations, and so on. GCC caches a lot of this type of + information in global variables, and recomputing them for each + subtarget takes a significant amount of time. The compiler + therefore provides a facility for maintaining several versions of + the global variables and quickly switching between them; see + `target-globals.h' for details. + + Define this macro to 1 if your target needs this facility. The + default is 0. + + +File: gccint.info, Node: Per-Function Data, Next: Storage Layout, Prev: Run-time Target, Up: Target Macros + +17.4 Defining data structures for per-function information. +=========================================================== + +If the target needs to store information on a per-function basis, GCC +provides a macro and a couple of variables to allow this. Note, just +using statics to store the information is a bad idea, since GCC supports +nested functions, so you can be halfway through encoding one function +when another one comes along. + + GCC defines a data structure called `struct function' which contains +all of the data specific to an individual function. This structure +contains a field called `machine' whose type is `struct +machine_function *', which can be used by targets to point to their own +specific data. + + If a target needs per-function specific data it should define the type +`struct machine_function' and also the macro `INIT_EXPANDERS'. This +macro should be used to initialize the function pointer +`init_machine_status'. This pointer is explained below. + + One typical use of per-function, target specific data is to create an +RTX to hold the register containing the function's return address. This +RTX can then be used to implement the `__builtin_return_address' +function, for level 0. + + Note--earlier implementations of GCC used a single data area to hold +all of the per-function information. Thus when processing of a nested +function began the old per-function data had to be pushed onto a stack, +and when the processing was finished, it had to be popped off the +stack. GCC used to provide function pointers called +`save_machine_status' and `restore_machine_status' to handle the saving +and restoring of the target specific information. Since the single +data area approach is no longer used, these pointers are no longer +supported. + + -- Macro: INIT_EXPANDERS + Macro called to initialize any target specific information. This + macro is called once per function, before generation of any RTL + has begun. The intention of this macro is to allow the + initialization of the function pointer `init_machine_status'. + + -- Variable: void (*)(struct function *) init_machine_status + If this function pointer is non-`NULL' it will be called once per + function, before function compilation starts, in order to allow the + target to perform any target specific initialization of the + `struct function' structure. It is intended that this would be + used to initialize the `machine' of that structure. + + `struct machine_function' structures are expected to be freed by + GC. Generally, any memory that they reference must be allocated + by using GC allocation, including the structure itself. + + +File: gccint.info, Node: Storage Layout, Next: Type Layout, Prev: Per-Function Data, Up: Target Macros + +17.5 Storage Layout +=================== + +Note that the definitions of the macros in this table which are sizes or +alignments measured in bits do not need to be constant. They can be C +expressions that refer to static variables, such as the `target_flags'. +*Note Run-time Target::. + + -- Macro: BITS_BIG_ENDIAN + Define this macro to have the value 1 if the most significant bit + in a byte has the lowest number; otherwise define it to have the + value zero. This means that bit-field instructions count from the + most significant bit. If the machine has no bit-field + instructions, then this must still be defined, but it doesn't + matter which value it is defined to. This macro need not be a + constant. + + This macro does not affect the way structure fields are packed into + bytes or words; that is controlled by `BYTES_BIG_ENDIAN'. + + -- Macro: BYTES_BIG_ENDIAN + Define this macro to have the value 1 if the most significant byte + in a word has the lowest number. This macro need not be a + constant. + + -- Macro: WORDS_BIG_ENDIAN + Define this macro to have the value 1 if, in a multiword object, + the most significant word has the lowest number. This applies to + both memory locations and registers; GCC fundamentally assumes + that the order of words in memory is the same as the order in + registers. This macro need not be a constant. + + -- Macro: FLOAT_WORDS_BIG_ENDIAN + Define this macro to have the value 1 if `DFmode', `XFmode' or + `TFmode' floating point numbers are stored in memory with the word + containing the sign bit at the lowest address; otherwise define it + to have the value 0. This macro need not be a constant. + + You need not define this macro if the ordering is the same as for + multi-word integers. + + -- Macro: BITS_PER_UNIT + Define this macro to be the number of bits in an addressable + storage unit (byte). If you do not define this macro the default + is 8. + + -- Macro: BITS_PER_WORD + Number of bits in a word. If you do not define this macro, the + default is `BITS_PER_UNIT * UNITS_PER_WORD'. + + -- Macro: MAX_BITS_PER_WORD + Maximum number of bits in a word. If this is undefined, the + default is `BITS_PER_WORD'. Otherwise, it is the constant value + that is the largest value that `BITS_PER_WORD' can have at + run-time. + + -- Macro: UNITS_PER_WORD + Number of storage units in a word; normally the size of a + general-purpose register, a power of two from 1 or 8. + + -- Macro: MIN_UNITS_PER_WORD + Minimum number of units in a word. If this is undefined, the + default is `UNITS_PER_WORD'. Otherwise, it is the constant value + that is the smallest value that `UNITS_PER_WORD' can have at + run-time. + + -- Macro: POINTER_SIZE + Width of a pointer, in bits. You must specify a value no wider + than the width of `Pmode'. If it is not equal to the width of + `Pmode', you must define `POINTERS_EXTEND_UNSIGNED'. If you do + not specify a value the default is `BITS_PER_WORD'. + + -- Macro: POINTERS_EXTEND_UNSIGNED + A C expression that determines how pointers should be extended from + `ptr_mode' to either `Pmode' or `word_mode'. It is greater than + zero if pointers should be zero-extended, zero if they should be + sign-extended, and negative if some other sort of conversion is + needed. In the last case, the extension is done by the target's + `ptr_extend' instruction. + + You need not define this macro if the `ptr_mode', `Pmode' and + `word_mode' are all the same width. + + -- Macro: PROMOTE_MODE (M, UNSIGNEDP, TYPE) + A macro to update M and UNSIGNEDP when an object whose type is + TYPE and which has the specified mode and signedness is to be + stored in a register. This macro is only called when TYPE is a + scalar type. + + On most RISC machines, which only have operations that operate on + a full register, define this macro to set M to `word_mode' if M is + an integer mode narrower than `BITS_PER_WORD'. In most cases, + only integer modes should be widened because wider-precision + floating-point operations are usually more expensive than their + narrower counterparts. + + For most machines, the macro definition does not change UNSIGNEDP. + However, some machines, have instructions that preferentially + handle either signed or unsigned quantities of certain modes. For + example, on the DEC Alpha, 32-bit loads from memory and 32-bit add + instructions sign-extend the result to 64 bits. On such machines, + set UNSIGNEDP according to which kind of extension is more + efficient. + + Do not define this macro if it would never modify M. + + -- Target Hook: enum machine_mode TARGET_PROMOTE_FUNCTION_MODE + (const_tree TYPE, enum machine_mode MODE, int *PUNSIGNEDP, + const_tree FUNTYPE, int FOR_RETURN) + Like `PROMOTE_MODE', but it is applied to outgoing function + arguments or function return values. The target hook should + return the new mode and possibly change `*PUNSIGNEDP' if the + promotion should change signedness. This function is called only + for scalar _or pointer_ types. + + FOR_RETURN allows to distinguish the promotion of arguments and + return values. If it is `1', a return value is being promoted and + `TARGET_FUNCTION_VALUE' must perform the same promotions done here. + If it is `2', the returned mode should be that of the register in + which an incoming parameter is copied, or the outgoing result is + computed; then the hook should return the same mode as + `promote_mode', though the signedness may be different. + + The default is to not promote arguments and return values. You can + also define the hook to + `default_promote_function_mode_always_promote' if you would like + to apply the same rules given by `PROMOTE_MODE'. + + -- Macro: PARM_BOUNDARY + Normal alignment required for function parameters on the stack, in + bits. All stack parameters receive at least this much alignment + regardless of data type. On most machines, this is the same as the + size of an integer. + + -- Macro: STACK_BOUNDARY + Define this macro to the minimum alignment enforced by hardware + for the stack pointer on this machine. The definition is a C + expression for the desired alignment (measured in bits). This + value is used as a default if `PREFERRED_STACK_BOUNDARY' is not + defined. On most machines, this should be the same as + `PARM_BOUNDARY'. + + -- Macro: PREFERRED_STACK_BOUNDARY + Define this macro if you wish to preserve a certain alignment for + the stack pointer, greater than what the hardware enforces. The + definition is a C expression for the desired alignment (measured + in bits). This macro must evaluate to a value equal to or larger + than `STACK_BOUNDARY'. + + -- Macro: INCOMING_STACK_BOUNDARY + Define this macro if the incoming stack boundary may be different + from `PREFERRED_STACK_BOUNDARY'. This macro must evaluate to a + value equal to or larger than `STACK_BOUNDARY'. + + -- Macro: FUNCTION_BOUNDARY + Alignment required for a function entry point, in bits. + + -- Macro: BIGGEST_ALIGNMENT + Biggest alignment that any data type can require on this machine, + in bits. Note that this is not the biggest alignment that is + supported, just the biggest alignment that, when violated, may + cause a fault. + + -- Macro: MALLOC_ABI_ALIGNMENT + Alignment, in bits, a C conformant malloc implementation has to + provide. If not defined, the default value is `BITS_PER_WORD'. + + -- Macro: ATTRIBUTE_ALIGNED_VALUE + Alignment used by the `__attribute__ ((aligned))' construct. If + not defined, the default value is `BIGGEST_ALIGNMENT'. + + -- Macro: MINIMUM_ATOMIC_ALIGNMENT + If defined, the smallest alignment, in bits, that can be given to + an object that can be referenced in one operation, without + disturbing any nearby object. Normally, this is `BITS_PER_UNIT', + but may be larger on machines that don't have byte or half-word + store operations. + + -- Macro: BIGGEST_FIELD_ALIGNMENT + Biggest alignment that any structure or union field can require on + this machine, in bits. If defined, this overrides + `BIGGEST_ALIGNMENT' for structure and union fields only, unless + the field alignment has been set by the `__attribute__ ((aligned + (N)))' construct. + + -- Macro: ADJUST_FIELD_ALIGN (FIELD, COMPUTED) + An expression for the alignment of a structure field FIELD if the + alignment computed in the usual way (including applying of + `BIGGEST_ALIGNMENT' and `BIGGEST_FIELD_ALIGNMENT' to the + alignment) is COMPUTED. It overrides alignment only if the field + alignment has not been set by the `__attribute__ ((aligned (N)))' + construct. + + -- Macro: MAX_STACK_ALIGNMENT + Biggest stack alignment guaranteed by the backend. Use this macro + to specify the maximum alignment of a variable on stack. + + If not defined, the default value is `STACK_BOUNDARY'. + + + -- Macro: MAX_OFILE_ALIGNMENT + Biggest alignment supported by the object file format of this + machine. Use this macro to limit the alignment which can be + specified using the `__attribute__ ((aligned (N)))' construct. If + not defined, the default value is `BIGGEST_ALIGNMENT'. + + On systems that use ELF, the default (in `config/elfos.h') is the + largest supported 32-bit ELF section alignment representable on a + 32-bit host e.g. `(((unsigned HOST_WIDEST_INT) 1 << 28) * 8)'. On + 32-bit ELF the largest supported section alignment in bits is + `(0x80000000 * 8)', but this is not representable on 32-bit hosts. + + -- Macro: DATA_ALIGNMENT (TYPE, BASIC-ALIGN) + If defined, a C expression to compute the alignment for a variable + in the static store. TYPE is the data type, and BASIC-ALIGN is + the alignment that the object would ordinarily have. The value of + this macro is used instead of that alignment to align the object. + + If this macro is not defined, then BASIC-ALIGN is used. + + One use of this macro is to increase alignment of medium-size data + to make it all fit in fewer cache lines. Another is to cause + character arrays to be word-aligned so that `strcpy' calls that + copy constants to character arrays can be done inline. + + -- Macro: CONSTANT_ALIGNMENT (CONSTANT, BASIC-ALIGN) + If defined, a C expression to compute the alignment given to a + constant that is being placed in memory. CONSTANT is the constant + and BASIC-ALIGN is the alignment that the object would ordinarily + have. The value of this macro is used instead of that alignment to + align the object. + + If this macro is not defined, then BASIC-ALIGN is used. + + The typical use of this macro is to increase alignment for string + constants to be word aligned so that `strcpy' calls that copy + constants can be done inline. + + -- Macro: LOCAL_ALIGNMENT (TYPE, BASIC-ALIGN) + If defined, a C expression to compute the alignment for a variable + in the local store. TYPE is the data type, and BASIC-ALIGN is the + alignment that the object would ordinarily have. The value of this + macro is used instead of that alignment to align the object. + + If this macro is not defined, then BASIC-ALIGN is used. + + One use of this macro is to increase alignment of medium-size data + to make it all fit in fewer cache lines. + + If the value of this macro has a type, it should be an unsigned + type. + + -- Macro: STACK_SLOT_ALIGNMENT (TYPE, MODE, BASIC-ALIGN) + If defined, a C expression to compute the alignment for stack slot. + TYPE is the data type, MODE is the widest mode available, and + BASIC-ALIGN is the alignment that the slot would ordinarily have. + The value of this macro is used instead of that alignment to align + the slot. + + If this macro is not defined, then BASIC-ALIGN is used when TYPE + is `NULL'. Otherwise, `LOCAL_ALIGNMENT' will be used. + + This macro is to set alignment of stack slot to the maximum + alignment of all possible modes which the slot may have. + + If the value of this macro has a type, it should be an unsigned + type. + + -- Macro: LOCAL_DECL_ALIGNMENT (DECL) + If defined, a C expression to compute the alignment for a local + variable DECL. + + If this macro is not defined, then `LOCAL_ALIGNMENT (TREE_TYPE + (DECL), DECL_ALIGN (DECL))' is used. + + One use of this macro is to increase alignment of medium-size data + to make it all fit in fewer cache lines. + + If the value of this macro has a type, it should be an unsigned + type. + + -- Macro: MINIMUM_ALIGNMENT (EXP, MODE, ALIGN) + If defined, a C expression to compute the minimum required + alignment for dynamic stack realignment purposes for EXP (a type + or decl), MODE, assuming normal alignment ALIGN. + + If this macro is not defined, then ALIGN will be used. + + -- Macro: EMPTY_FIELD_BOUNDARY + Alignment in bits to be given to a structure bit-field that + follows an empty field such as `int : 0;'. + + If `PCC_BITFIELD_TYPE_MATTERS' is true, it overrides this macro. + + -- Macro: STRUCTURE_SIZE_BOUNDARY + Number of bits which any structure or union's size must be a + multiple of. Each structure or union's size is rounded up to a + multiple of this. + + If you do not define this macro, the default is the same as + `BITS_PER_UNIT'. + + -- Macro: STRICT_ALIGNMENT + Define this macro to be the value 1 if instructions will fail to + work if given data not on the nominal alignment. If instructions + will merely go slower in that case, define this macro as 0. + + -- Macro: PCC_BITFIELD_TYPE_MATTERS + Define this if you wish to imitate the way many other C compilers + handle alignment of bit-fields and the structures that contain + them. + + The behavior is that the type written for a named bit-field (`int', + `short', or other integer type) imposes an alignment for the entire + structure, as if the structure really did contain an ordinary + field of that type. In addition, the bit-field is placed within + the structure so that it would fit within such a field, not + crossing a boundary for it. + + Thus, on most machines, a named bit-field whose type is written as + `int' would not cross a four-byte boundary, and would force + four-byte alignment for the whole structure. (The alignment used + may not be four bytes; it is controlled by the other alignment + parameters.) + + An unnamed bit-field will not affect the alignment of the + containing structure. + + If the macro is defined, its definition should be a C expression; + a nonzero value for the expression enables this behavior. + + Note that if this macro is not defined, or its value is zero, some + bit-fields may cross more than one alignment boundary. The + compiler can support such references if there are `insv', `extv', + and `extzv' insns that can directly reference memory. + + The other known way of making bit-fields work is to define + `STRUCTURE_SIZE_BOUNDARY' as large as `BIGGEST_ALIGNMENT'. Then + every structure can be accessed with fullwords. + + Unless the machine has bit-field instructions or you define + `STRUCTURE_SIZE_BOUNDARY' that way, you must define + `PCC_BITFIELD_TYPE_MATTERS' to have a nonzero value. + + If your aim is to make GCC use the same conventions for laying out + bit-fields as are used by another compiler, here is how to + investigate what the other compiler does. Compile and run this + program: + + struct foo1 + { + char x; + char :0; + char y; + }; + + struct foo2 + { + char x; + int :0; + char y; + }; + + main () + { + printf ("Size of foo1 is %d\n", + sizeof (struct foo1)); + printf ("Size of foo2 is %d\n", + sizeof (struct foo2)); + exit (0); + } + + If this prints 2 and 5, then the compiler's behavior is what you + would get from `PCC_BITFIELD_TYPE_MATTERS'. + + -- Macro: BITFIELD_NBYTES_LIMITED + Like `PCC_BITFIELD_TYPE_MATTERS' except that its effect is limited + to aligning a bit-field within the structure. + + -- Target Hook: bool TARGET_ALIGN_ANON_BITFIELD (void) + When `PCC_BITFIELD_TYPE_MATTERS' is true this hook will determine + whether unnamed bitfields affect the alignment of the containing + structure. The hook should return true if the structure should + inherit the alignment requirements of an unnamed bitfield's type. + + -- Target Hook: bool TARGET_NARROW_VOLATILE_BITFIELD (void) + This target hook should return `true' if accesses to volatile + bitfields should use the narrowest mode possible. It should + return `false' if these accesses should use the bitfield container + type. + + The default is `!TARGET_STRICT_ALIGN'. + + -- Macro: MEMBER_TYPE_FORCES_BLK (FIELD, MODE) + Return 1 if a structure or array containing FIELD should be + accessed using `BLKMODE'. + + If FIELD is the only field in the structure, MODE is its mode, + otherwise MODE is VOIDmode. MODE is provided in the case where + structures of one field would require the structure's mode to + retain the field's mode. + + Normally, this is not needed. + + -- Macro: ROUND_TYPE_ALIGN (TYPE, COMPUTED, SPECIFIED) + Define this macro as an expression for the alignment of a type + (given by TYPE as a tree node) if the alignment computed in the + usual way is COMPUTED and the alignment explicitly specified was + SPECIFIED. + + The default is to use SPECIFIED if it is larger; otherwise, use + the smaller of COMPUTED and `BIGGEST_ALIGNMENT' + + -- Macro: MAX_FIXED_MODE_SIZE + An integer expression for the size in bits of the largest integer + machine mode that should actually be used. All integer machine + modes of this size or smaller can be used for structures and + unions with the appropriate sizes. If this macro is undefined, + `GET_MODE_BITSIZE (DImode)' is assumed. + + -- Macro: STACK_SAVEAREA_MODE (SAVE_LEVEL) + If defined, an expression of type `enum machine_mode' that + specifies the mode of the save area operand of a + `save_stack_LEVEL' named pattern (*note Standard Names::). + SAVE_LEVEL is one of `SAVE_BLOCK', `SAVE_FUNCTION', or + `SAVE_NONLOCAL' and selects which of the three named patterns is + having its mode specified. + + You need not define this macro if it always returns `Pmode'. You + would most commonly define this macro if the `save_stack_LEVEL' + patterns need to support both a 32- and a 64-bit mode. + + -- Macro: STACK_SIZE_MODE + If defined, an expression of type `enum machine_mode' that + specifies the mode of the size increment operand of an + `allocate_stack' named pattern (*note Standard Names::). + + You need not define this macro if it always returns `word_mode'. + You would most commonly define this macro if the `allocate_stack' + pattern needs to support both a 32- and a 64-bit mode. + + -- Target Hook: enum machine_mode TARGET_LIBGCC_CMP_RETURN_MODE (void) + This target hook should return the mode to be used for the return + value of compare instructions expanded to libgcc calls. If not + defined `word_mode' is returned which is the right choice for a + majority of targets. + + -- Target Hook: enum machine_mode TARGET_LIBGCC_SHIFT_COUNT_MODE (void) + This target hook should return the mode to be used for the shift + count operand of shift instructions expanded to libgcc calls. If + not defined `word_mode' is returned which is the right choice for + a majority of targets. + + -- Target Hook: enum machine_mode TARGET_UNWIND_WORD_MODE (void) + Return machine mode to be used for `_Unwind_Word' type. The + default is to use `word_mode'. + + -- Macro: ROUND_TOWARDS_ZERO + If defined, this macro should be true if the prevailing rounding + mode is towards zero. + + Defining this macro only affects the way `libgcc.a' emulates + floating-point arithmetic. + + Not defining this macro is equivalent to returning zero. + + -- Macro: LARGEST_EXPONENT_IS_NORMAL (SIZE) + This macro should return true if floats with SIZE bits do not have + a NaN or infinity representation, but use the largest exponent for + normal numbers instead. + + Defining this macro only affects the way `libgcc.a' emulates + floating-point arithmetic. + + The default definition of this macro returns false for all sizes. + + -- Target Hook: bool TARGET_MS_BITFIELD_LAYOUT_P (const_tree + RECORD_TYPE) + This target hook returns `true' if bit-fields in the given + RECORD_TYPE are to be laid out following the rules of Microsoft + Visual C/C++, namely: (i) a bit-field won't share the same storage + unit with the previous bit-field if their underlying types have + different sizes, and the bit-field will be aligned to the highest + alignment of the underlying types of itself and of the previous + bit-field; (ii) a zero-sized bit-field will affect the alignment of + the whole enclosing structure, even if it is unnamed; except that + (iii) a zero-sized bit-field will be disregarded unless it follows + another bit-field of nonzero size. If this hook returns `true', + other macros that control bit-field layout are ignored. + + When a bit-field is inserted into a packed record, the whole size + of the underlying type is used by one or more same-size adjacent + bit-fields (that is, if its long:3, 32 bits is used in the record, + and any additional adjacent long bit-fields are packed into the + same chunk of 32 bits. However, if the size changes, a new field + of that size is allocated). In an unpacked record, this is the + same as using alignment, but not equivalent when packing. + + If both MS bit-fields and `__attribute__((packed))' are used, the + latter will take precedence. If `__attribute__((packed))' is used + on a single field when MS bit-fields are in use, it will take + precedence for that field, but the alignment of the rest of the + structure may affect its placement. + + -- Target Hook: bool TARGET_DECIMAL_FLOAT_SUPPORTED_P (void) + Returns true if the target supports decimal floating point. + + -- Target Hook: bool TARGET_FIXED_POINT_SUPPORTED_P (void) + Returns true if the target supports fixed-point arithmetic. + + -- Target Hook: void TARGET_EXPAND_TO_RTL_HOOK (void) + This hook is called just before expansion into rtl, allowing the + target to perform additional initializations or analysis before + the expansion. For example, the rs6000 port uses it to allocate a + scratch stack slot for use in copying SDmode values between memory + and floating point registers whenever the function being expanded + has any SDmode usage. + + -- Target Hook: void TARGET_INSTANTIATE_DECLS (void) + This hook allows the backend to perform additional instantiations + on rtl that are not actually in any insns yet, but will be later. + + -- Target Hook: const char * TARGET_MANGLE_TYPE (const_tree TYPE) + If your target defines any fundamental types, or any types your + target uses should be mangled differently from the default, define + this hook to return the appropriate encoding for these types as + part of a C++ mangled name. The TYPE argument is the tree + structure representing the type to be mangled. The hook may be + applied to trees which are not target-specific fundamental types; + it should return `NULL' for all such types, as well as arguments + it does not recognize. If the return value is not `NULL', it must + point to a statically-allocated string constant. + + Target-specific fundamental types might be new fundamental types or + qualified versions of ordinary fundamental types. Encode new + fundamental types as `u N NAME', where NAME is the name used for + the type in source code, and N is the length of NAME in decimal. + Encode qualified versions of ordinary types as `U N NAME CODE', + where NAME is the name used for the type qualifier in source code, + N is the length of NAME as above, and CODE is the code used to + represent the unqualified version of this type. (See + `write_builtin_type' in `cp/mangle.c' for the list of codes.) In + both cases the spaces are for clarity; do not include any spaces + in your string. + + This hook is applied to types prior to typedef resolution. If the + mangled name for a particular type depends only on that type's + main variant, you can perform typedef resolution yourself using + `TYPE_MAIN_VARIANT' before mangling. + + The default version of this hook always returns `NULL', which is + appropriate for a target that does not define any new fundamental + types. + + +File: gccint.info, Node: Type Layout, Next: Registers, Prev: Storage Layout, Up: Target Macros + +17.6 Layout of Source Language Data Types +========================================= + +These macros define the sizes and other characteristics of the standard +basic data types used in programs being compiled. Unlike the macros in +the previous section, these apply to specific features of C and related +languages, rather than to fundamental aspects of storage layout. + + -- Macro: INT_TYPE_SIZE + A C expression for the size in bits of the type `int' on the + target machine. If you don't define this, the default is one word. + + -- Macro: SHORT_TYPE_SIZE + A C expression for the size in bits of the type `short' on the + target machine. If you don't define this, the default is half a + word. (If this would be less than one storage unit, it is rounded + up to one unit.) + + -- Macro: LONG_TYPE_SIZE + A C expression for the size in bits of the type `long' on the + target machine. If you don't define this, the default is one word. + + -- Macro: ADA_LONG_TYPE_SIZE + On some machines, the size used for the Ada equivalent of the type + `long' by a native Ada compiler differs from that used by C. In + that situation, define this macro to be a C expression to be used + for the size of that type. If you don't define this, the default + is the value of `LONG_TYPE_SIZE'. + + -- Macro: LONG_LONG_TYPE_SIZE + A C expression for the size in bits of the type `long long' on the + target machine. If you don't define this, the default is two + words. If you want to support GNU Ada on your machine, the value + of this macro must be at least 64. + + -- Macro: CHAR_TYPE_SIZE + A C expression for the size in bits of the type `char' on the + target machine. If you don't define this, the default is + `BITS_PER_UNIT'. + + -- Macro: BOOL_TYPE_SIZE + A C expression for the size in bits of the C++ type `bool' and C99 + type `_Bool' on the target machine. If you don't define this, and + you probably shouldn't, the default is `CHAR_TYPE_SIZE'. + + -- Macro: FLOAT_TYPE_SIZE + A C expression for the size in bits of the type `float' on the + target machine. If you don't define this, the default is one word. + + -- Macro: DOUBLE_TYPE_SIZE + A C expression for the size in bits of the type `double' on the + target machine. If you don't define this, the default is two + words. + + -- Macro: LONG_DOUBLE_TYPE_SIZE + A C expression for the size in bits of the type `long double' on + the target machine. If you don't define this, the default is two + words. + + -- Macro: SHORT_FRACT_TYPE_SIZE + A C expression for the size in bits of the type `short _Fract' on + the target machine. If you don't define this, the default is + `BITS_PER_UNIT'. + + -- Macro: FRACT_TYPE_SIZE + A C expression for the size in bits of the type `_Fract' on the + target machine. If you don't define this, the default is + `BITS_PER_UNIT * 2'. + + -- Macro: LONG_FRACT_TYPE_SIZE + A C expression for the size in bits of the type `long _Fract' on + the target machine. If you don't define this, the default is + `BITS_PER_UNIT * 4'. + + -- Macro: LONG_LONG_FRACT_TYPE_SIZE + A C expression for the size in bits of the type `long long _Fract' + on the target machine. If you don't define this, the default is + `BITS_PER_UNIT * 8'. + + -- Macro: SHORT_ACCUM_TYPE_SIZE + A C expression for the size in bits of the type `short _Accum' on + the target machine. If you don't define this, the default is + `BITS_PER_UNIT * 2'. + + -- Macro: ACCUM_TYPE_SIZE + A C expression for the size in bits of the type `_Accum' on the + target machine. If you don't define this, the default is + `BITS_PER_UNIT * 4'. + + -- Macro: LONG_ACCUM_TYPE_SIZE + A C expression for the size in bits of the type `long _Accum' on + the target machine. If you don't define this, the default is + `BITS_PER_UNIT * 8'. + + -- Macro: LONG_LONG_ACCUM_TYPE_SIZE + A C expression for the size in bits of the type `long long _Accum' + on the target machine. If you don't define this, the default is + `BITS_PER_UNIT * 16'. + + -- Macro: LIBGCC2_LONG_DOUBLE_TYPE_SIZE + Define this macro if `LONG_DOUBLE_TYPE_SIZE' is not constant or if + you want routines in `libgcc2.a' for a size other than + `LONG_DOUBLE_TYPE_SIZE'. If you don't define this, the default is + `LONG_DOUBLE_TYPE_SIZE'. + + -- Macro: LIBGCC2_HAS_DF_MODE + Define this macro if neither `DOUBLE_TYPE_SIZE' nor + `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is `DFmode' but you want `DFmode' + routines in `libgcc2.a' anyway. If you don't define this and + either `DOUBLE_TYPE_SIZE' or `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 64 + then the default is 1, otherwise it is 0. + + -- Macro: LIBGCC2_HAS_XF_MODE + Define this macro if `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is not + `XFmode' but you want `XFmode' routines in `libgcc2.a' anyway. If + you don't define this and `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 80 + then the default is 1, otherwise it is 0. + + -- Macro: LIBGCC2_HAS_TF_MODE + Define this macro if `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is not + `TFmode' but you want `TFmode' routines in `libgcc2.a' anyway. If + you don't define this and `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is 128 + then the default is 1, otherwise it is 0. + + -- Macro: SF_SIZE + -- Macro: DF_SIZE + -- Macro: XF_SIZE + -- Macro: TF_SIZE + Define these macros to be the size in bits of the mantissa of + `SFmode', `DFmode', `XFmode' and `TFmode' values, if the defaults + in `libgcc2.h' are inappropriate. By default, `FLT_MANT_DIG' is + used for `SF_SIZE', `LDBL_MANT_DIG' for `XF_SIZE' and `TF_SIZE', + and `DBL_MANT_DIG' or `LDBL_MANT_DIG' for `DF_SIZE' according to + whether `DOUBLE_TYPE_SIZE' or `LIBGCC2_LONG_DOUBLE_TYPE_SIZE' is + 64. + + -- Macro: TARGET_FLT_EVAL_METHOD + A C expression for the value for `FLT_EVAL_METHOD' in `float.h', + assuming, if applicable, that the floating-point control word is + in its default state. If you do not define this macro the value of + `FLT_EVAL_METHOD' will be zero. + + -- Macro: WIDEST_HARDWARE_FP_SIZE + A C expression for the size in bits of the widest floating-point + format supported by the hardware. If you define this macro, you + must specify a value less than or equal to the value of + `LONG_DOUBLE_TYPE_SIZE'. If you do not define this macro, the + value of `LONG_DOUBLE_TYPE_SIZE' is the default. + + -- Macro: DEFAULT_SIGNED_CHAR + An expression whose value is 1 or 0, according to whether the type + `char' should be signed or unsigned by default. The user can + always override this default with the options `-fsigned-char' and + `-funsigned-char'. + + -- Target Hook: bool TARGET_DEFAULT_SHORT_ENUMS (void) + This target hook should return true if the compiler should give an + `enum' type only as many bytes as it takes to represent the range + of possible values of that type. It should return false if all + `enum' types should be allocated like `int'. + + The default is to return false. + + -- Macro: SIZE_TYPE + A C expression for a string describing the name of the data type + to use for size values. The typedef name `size_t' is defined + using the contents of the string. + + The string can contain more than one keyword. If so, separate + them with spaces, and write first any length keyword, then + `unsigned' if appropriate, and finally `int'. The string must + exactly match one of the data type names defined in the function + `init_decl_processing' in the file `c-decl.c'. You may not omit + `int' or change the order--that would cause the compiler to crash + on startup. + + If you don't define this macro, the default is `"long unsigned + int"'. + + -- Macro: PTRDIFF_TYPE + A C expression for a string describing the name of the data type + to use for the result of subtracting two pointers. The typedef + name `ptrdiff_t' is defined using the contents of the string. See + `SIZE_TYPE' above for more information. + + If you don't define this macro, the default is `"long int"'. + + -- Macro: WCHAR_TYPE + A C expression for a string describing the name of the data type + to use for wide characters. The typedef name `wchar_t' is defined + using the contents of the string. See `SIZE_TYPE' above for more + information. + + If you don't define this macro, the default is `"int"'. + + -- Macro: WCHAR_TYPE_SIZE + A C expression for the size in bits of the data type for wide + characters. This is used in `cpp', which cannot make use of + `WCHAR_TYPE'. + + -- Macro: WINT_TYPE + A C expression for a string describing the name of the data type to + use for wide characters passed to `printf' and returned from + `getwc'. The typedef name `wint_t' is defined using the contents + of the string. See `SIZE_TYPE' above for more information. + + If you don't define this macro, the default is `"unsigned int"'. + + -- Macro: INTMAX_TYPE + A C expression for a string describing the name of the data type + that can represent any value of any standard or extended signed + integer type. The typedef name `intmax_t' is defined using the + contents of the string. See `SIZE_TYPE' above for more + information. + + If you don't define this macro, the default is the first of + `"int"', `"long int"', or `"long long int"' that has as much + precision as `long long int'. + + -- Macro: UINTMAX_TYPE + A C expression for a string describing the name of the data type + that can represent any value of any standard or extended unsigned + integer type. The typedef name `uintmax_t' is defined using the + contents of the string. See `SIZE_TYPE' above for more + information. + + If you don't define this macro, the default is the first of + `"unsigned int"', `"long unsigned int"', or `"long long unsigned + int"' that has as much precision as `long long unsigned int'. + + -- Macro: SIG_ATOMIC_TYPE + -- Macro: INT8_TYPE + -- Macro: INT16_TYPE + -- Macro: INT32_TYPE + -- Macro: INT64_TYPE + -- Macro: UINT8_TYPE + -- Macro: UINT16_TYPE + -- Macro: UINT32_TYPE + -- Macro: UINT64_TYPE + -- Macro: INT_LEAST8_TYPE + -- Macro: INT_LEAST16_TYPE + -- Macro: INT_LEAST32_TYPE + -- Macro: INT_LEAST64_TYPE + -- Macro: UINT_LEAST8_TYPE + -- Macro: UINT_LEAST16_TYPE + -- Macro: UINT_LEAST32_TYPE + -- Macro: UINT_LEAST64_TYPE + -- Macro: INT_FAST8_TYPE + -- Macro: INT_FAST16_TYPE + -- Macro: INT_FAST32_TYPE + -- Macro: INT_FAST64_TYPE + -- Macro: UINT_FAST8_TYPE + -- Macro: UINT_FAST16_TYPE + -- Macro: UINT_FAST32_TYPE + -- Macro: UINT_FAST64_TYPE + -- Macro: INTPTR_TYPE + -- Macro: UINTPTR_TYPE + C expressions for the standard types `sig_atomic_t', `int8_t', + `int16_t', `int32_t', `int64_t', `uint8_t', `uint16_t', + `uint32_t', `uint64_t', `int_least8_t', `int_least16_t', + `int_least32_t', `int_least64_t', `uint_least8_t', + `uint_least16_t', `uint_least32_t', `uint_least64_t', + `int_fast8_t', `int_fast16_t', `int_fast32_t', `int_fast64_t', + `uint_fast8_t', `uint_fast16_t', `uint_fast32_t', `uint_fast64_t', + `intptr_t', and `uintptr_t'. See `SIZE_TYPE' above for more + information. + + If any of these macros evaluates to a null pointer, the + corresponding type is not supported; if GCC is configured to + provide `<stdint.h>' in such a case, the header provided may not + conform to C99, depending on the type in question. The defaults + for all of these macros are null pointers. + + -- Macro: TARGET_PTRMEMFUNC_VBIT_LOCATION + The C++ compiler represents a pointer-to-member-function with a + struct that looks like: + + struct { + union { + void (*fn)(); + ptrdiff_t vtable_index; + }; + ptrdiff_t delta; + }; + + The C++ compiler must use one bit to indicate whether the function + that will be called through a pointer-to-member-function is + virtual. Normally, we assume that the low-order bit of a function + pointer must always be zero. Then, by ensuring that the + vtable_index is odd, we can distinguish which variant of the union + is in use. But, on some platforms function pointers can be odd, + and so this doesn't work. In that case, we use the low-order bit + of the `delta' field, and shift the remainder of the `delta' field + to the left. + + GCC will automatically make the right selection about where to + store this bit using the `FUNCTION_BOUNDARY' setting for your + platform. However, some platforms such as ARM/Thumb have + `FUNCTION_BOUNDARY' set such that functions always start at even + addresses, but the lowest bit of pointers to functions indicate + whether the function at that address is in ARM or Thumb mode. If + this is the case of your architecture, you should define this + macro to `ptrmemfunc_vbit_in_delta'. + + In general, you should not have to define this macro. On + architectures in which function addresses are always even, + according to `FUNCTION_BOUNDARY', GCC will automatically define + this macro to `ptrmemfunc_vbit_in_pfn'. + + -- Macro: TARGET_VTABLE_USES_DESCRIPTORS + Normally, the C++ compiler uses function pointers in vtables. This + macro allows the target to change to use "function descriptors" + instead. Function descriptors are found on targets for whom a + function pointer is actually a small data structure. Normally the + data structure consists of the actual code address plus a data + pointer to which the function's data is relative. + + If vtables are used, the value of this macro should be the number + of words that the function descriptor occupies. + + -- Macro: TARGET_VTABLE_ENTRY_ALIGN + By default, the vtable entries are void pointers, the so the + alignment is the same as pointer alignment. The value of this + macro specifies the alignment of the vtable entry in bits. It + should be defined only when special alignment is necessary. */ + + -- Macro: TARGET_VTABLE_DATA_ENTRY_DISTANCE + There are a few non-descriptor entries in the vtable at offsets + below zero. If these entries must be padded (say, to preserve the + alignment specified by `TARGET_VTABLE_ENTRY_ALIGN'), set this to + the number of words in each data entry. + + +File: gccint.info, Node: Registers, Next: Register Classes, Prev: Type Layout, Up: Target Macros + +17.7 Register Usage +=================== + +This section explains how to describe what registers the target machine +has, and how (in general) they can be used. + + The description of which registers a specific instruction can use is +done with register classes; see *note Register Classes::. For +information on using registers to access a stack frame, see *note Frame +Registers::. For passing values in registers, see *note Register +Arguments::. For returning values in registers, see *note Scalar +Return::. + +* Menu: + +* Register Basics:: Number and kinds of registers. +* Allocation Order:: Order in which registers are allocated. +* Values in Registers:: What kinds of values each reg can hold. +* Leaf Functions:: Renumbering registers for leaf functions. +* Stack Registers:: Handling a register stack such as 80387. + + +File: gccint.info, Node: Register Basics, Next: Allocation Order, Up: Registers + +17.7.1 Basic Characteristics of Registers +----------------------------------------- + +Registers have various characteristics. + + -- Macro: FIRST_PSEUDO_REGISTER + Number of hardware registers known to the compiler. They receive + numbers 0 through `FIRST_PSEUDO_REGISTER-1'; thus, the first + pseudo register's number really is assigned the number + `FIRST_PSEUDO_REGISTER'. + + -- Macro: FIXED_REGISTERS + An initializer that says which registers are used for fixed + purposes all throughout the compiled code and are therefore not + available for general allocation. These would include the stack + pointer, the frame pointer (except on machines where that can be + used as a general register when no frame pointer is needed), the + program counter on machines where that is considered one of the + addressable registers, and any other numbered register with a + standard use. + + This information is expressed as a sequence of numbers, separated + by commas and surrounded by braces. The Nth number is 1 if + register N is fixed, 0 otherwise. + + The table initialized from this macro, and the table initialized by + the following one, may be overridden at run time either + automatically, by the actions of the macro + `CONDITIONAL_REGISTER_USAGE', or by the user with the command + options `-ffixed-REG', `-fcall-used-REG' and `-fcall-saved-REG'. + + -- Macro: CALL_USED_REGISTERS + Like `FIXED_REGISTERS' but has 1 for each register that is + clobbered (in general) by function calls as well as for fixed + registers. This macro therefore identifies the registers that are + not available for general allocation of values that must live + across function calls. + + If a register has 0 in `CALL_USED_REGISTERS', the compiler + automatically saves it on function entry and restores it on + function exit, if the register is used within the function. + + -- Macro: CALL_REALLY_USED_REGISTERS + Like `CALL_USED_REGISTERS' except this macro doesn't require that + the entire set of `FIXED_REGISTERS' be included. + (`CALL_USED_REGISTERS' must be a superset of `FIXED_REGISTERS'). + This macro is optional. If not specified, it defaults to the value + of `CALL_USED_REGISTERS'. + + -- Macro: HARD_REGNO_CALL_PART_CLOBBERED (REGNO, MODE) + A C expression that is nonzero if it is not permissible to store a + value of mode MODE in hard register number REGNO across a call + without some part of it being clobbered. For most machines this + macro need not be defined. It is only required for machines that + do not preserve the entire contents of a register across a call. + + -- Target Hook: void TARGET_CONDITIONAL_REGISTER_USAGE (void) + This hook may conditionally modify five variables `fixed_regs', + `call_used_regs', `global_regs', `reg_names', and + `reg_class_contents', to take into account any dependence of these + register sets on target flags. The first three of these are of + type `char []' (interpreted as Boolean vectors). `global_regs' is + a `const char *[]', and `reg_class_contents' is a `HARD_REG_SET'. + Before the macro is called, `fixed_regs', `call_used_regs', + `reg_class_contents', and `reg_names' have been initialized from + `FIXED_REGISTERS', `CALL_USED_REGISTERS', `REG_CLASS_CONTENTS', + and `REGISTER_NAMES', respectively. `global_regs' has been + cleared, and any `-ffixed-REG', `-fcall-used-REG' and + `-fcall-saved-REG' command options have been applied. + + If the usage of an entire class of registers depends on the target + flags, you may indicate this to GCC by using this macro to modify + `fixed_regs' and `call_used_regs' to 1 for each of the registers + in the classes which should not be used by GCC. Also define the + macro `REG_CLASS_FROM_LETTER' / `REG_CLASS_FROM_CONSTRAINT' to + return `NO_REGS' if it is called with a letter for a class that + shouldn't be used. + + (However, if this class is not included in `GENERAL_REGS' and all + of the insn patterns whose constraints permit this class are + controlled by target switches, then GCC will automatically avoid + using these registers when the target switches are opposed to + them.) + + -- Macro: INCOMING_REGNO (OUT) + Define this macro if the target machine has register windows. + This C expression returns the register number as seen by the + called function corresponding to the register number OUT as seen + by the calling function. Return OUT if register number OUT is not + an outbound register. + + -- Macro: OUTGOING_REGNO (IN) + Define this macro if the target machine has register windows. + This C expression returns the register number as seen by the + calling function corresponding to the register number IN as seen + by the called function. Return IN if register number IN is not an + inbound register. + + -- Macro: LOCAL_REGNO (REGNO) + Define this macro if the target machine has register windows. + This C expression returns true if the register is call-saved but + is in the register window. Unlike most call-saved registers, such + registers need not be explicitly restored on function exit or + during non-local gotos. + + -- Macro: PC_REGNUM + If the program counter has a register number, define this as that + register number. Otherwise, do not define it. + + +File: gccint.info, Node: Allocation Order, Next: Values in Registers, Prev: Register Basics, Up: Registers + +17.7.2 Order of Allocation of Registers +--------------------------------------- + +Registers are allocated in order. + + -- Macro: REG_ALLOC_ORDER + If defined, an initializer for a vector of integers, containing the + numbers of hard registers in the order in which GCC should prefer + to use them (from most preferred to least). + + If this macro is not defined, registers are used lowest numbered + first (all else being equal). + + One use of this macro is on machines where the highest numbered + registers must always be saved and the save-multiple-registers + instruction supports only sequences of consecutive registers. On + such machines, define `REG_ALLOC_ORDER' to be an initializer that + lists the highest numbered allocable register first. + + -- Macro: ADJUST_REG_ALLOC_ORDER + A C statement (sans semicolon) to choose the order in which to + allocate hard registers for pseudo-registers local to a basic + block. + + Store the desired register order in the array `reg_alloc_order'. + Element 0 should be the register to allocate first; element 1, the + next register; and so on. + + The macro body should not assume anything about the contents of + `reg_alloc_order' before execution of the macro. + + On most machines, it is not necessary to define this macro. + + -- Macro: HONOR_REG_ALLOC_ORDER + Normally, IRA tries to estimate the costs for saving a register in + the prologue and restoring it in the epilogue. This discourages + it from using call-saved registers. If a machine wants to ensure + that IRA allocates registers in the order given by REG_ALLOC_ORDER + even if some call-saved registers appear earlier than call-used + ones, this macro should be defined. + + -- Macro: IRA_HARD_REGNO_ADD_COST_MULTIPLIER (REGNO) + In some case register allocation order is not enough for the + Integrated Register Allocator (IRA) to generate a good code. If + this macro is defined, it should return a floating point value + based on REGNO. The cost of using REGNO for a pseudo will be + increased by approximately the pseudo's usage frequency times the + value returned by this macro. Not defining this macro is + equivalent to having it always return `0.0'. + + On most machines, it is not necessary to define this macro. + + +File: gccint.info, Node: Values in Registers, Next: Leaf Functions, Prev: Allocation Order, Up: Registers + +17.7.3 How Values Fit in Registers +---------------------------------- + +This section discusses the macros that describe which kinds of values +(specifically, which machine modes) each register can hold, and how many +consecutive registers are needed for a given mode. + + -- Macro: HARD_REGNO_NREGS (REGNO, MODE) + A C expression for the number of consecutive hard registers, + starting at register number REGNO, required to hold a value of mode + MODE. This macro must never return zero, even if a register + cannot hold the requested mode - indicate that with + HARD_REGNO_MODE_OK and/or CANNOT_CHANGE_MODE_CLASS instead. + + On a machine where all registers are exactly one word, a suitable + definition of this macro is + + #define HARD_REGNO_NREGS(REGNO, MODE) \ + ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) \ + / UNITS_PER_WORD) + + -- Macro: HARD_REGNO_NREGS_HAS_PADDING (REGNO, MODE) + A C expression that is nonzero if a value of mode MODE, stored in + memory, ends with padding that causes it to take up more space than + in registers starting at register number REGNO (as determined by + multiplying GCC's notion of the size of the register when + containing this mode by the number of registers returned by + `HARD_REGNO_NREGS'). By default this is zero. + + For example, if a floating-point value is stored in three 32-bit + registers but takes up 128 bits in memory, then this would be + nonzero. + + This macros only needs to be defined if there are cases where + `subreg_get_info' would otherwise wrongly determine that a + `subreg' can be represented by an offset to the register number, + when in fact such a `subreg' would contain some of the padding not + stored in registers and so not be representable. + + -- Macro: HARD_REGNO_NREGS_WITH_PADDING (REGNO, MODE) + For values of REGNO and MODE for which + `HARD_REGNO_NREGS_HAS_PADDING' returns nonzero, a C expression + returning the greater number of registers required to hold the + value including any padding. In the example above, the value + would be four. + + -- Macro: REGMODE_NATURAL_SIZE (MODE) + Define this macro if the natural size of registers that hold values + of mode MODE is not the word size. It is a C expression that + should give the natural size in bytes for the specified mode. It + is used by the register allocator to try to optimize its results. + This happens for example on SPARC 64-bit where the natural size of + floating-point registers is still 32-bit. + + -- Macro: HARD_REGNO_MODE_OK (REGNO, MODE) + A C expression that is nonzero if it is permissible to store a + value of mode MODE in hard register number REGNO (or in several + registers starting with that one). For a machine where all + registers are equivalent, a suitable definition is + + #define HARD_REGNO_MODE_OK(REGNO, MODE) 1 + + You need not include code to check for the numbers of fixed + registers, because the allocation mechanism considers them to be + always occupied. + + On some machines, double-precision values must be kept in even/odd + register pairs. You can implement that by defining this macro to + reject odd register numbers for such modes. + + The minimum requirement for a mode to be OK in a register is that + the `movMODE' instruction pattern support moves between the + register and other hard register in the same class and that moving + a value into the register and back out not alter it. + + Since the same instruction used to move `word_mode' will work for + all narrower integer modes, it is not necessary on any machine for + `HARD_REGNO_MODE_OK' to distinguish between these modes, provided + you define patterns `movhi', etc., to take advantage of this. This + is useful because of the interaction between `HARD_REGNO_MODE_OK' + and `MODES_TIEABLE_P'; it is very desirable for all integer modes + to be tieable. + + Many machines have special registers for floating point arithmetic. + Often people assume that floating point machine modes are allowed + only in floating point registers. This is not true. Any + registers that can hold integers can safely _hold_ a floating + point machine mode, whether or not floating arithmetic can be done + on it in those registers. Integer move instructions can be used + to move the values. + + On some machines, though, the converse is true: fixed-point machine + modes may not go in floating registers. This is true if the + floating registers normalize any value stored in them, because + storing a non-floating value there would garble it. In this case, + `HARD_REGNO_MODE_OK' should reject fixed-point machine modes in + floating registers. But if the floating registers do not + automatically normalize, if you can store any bit pattern in one + and retrieve it unchanged without a trap, then any machine mode + may go in a floating register, so you can define this macro to say + so. + + The primary significance of special floating registers is rather + that they are the registers acceptable in floating point arithmetic + instructions. However, this is of no concern to + `HARD_REGNO_MODE_OK'. You handle it by writing the proper + constraints for those instructions. + + On some machines, the floating registers are especially slow to + access, so that it is better to store a value in a stack frame + than in such a register if floating point arithmetic is not being + done. As long as the floating registers are not in class + `GENERAL_REGS', they will not be used unless some pattern's + constraint asks for one. + + -- Macro: HARD_REGNO_RENAME_OK (FROM, TO) + A C expression that is nonzero if it is OK to rename a hard + register FROM to another hard register TO. + + One common use of this macro is to prevent renaming of a register + to another register that is not saved by a prologue in an interrupt + handler. + + The default is always nonzero. + + -- Macro: MODES_TIEABLE_P (MODE1, MODE2) + A C expression that is nonzero if a value of mode MODE1 is + accessible in mode MODE2 without copying. + + If `HARD_REGNO_MODE_OK (R, MODE1)' and `HARD_REGNO_MODE_OK (R, + MODE2)' are always the same for any R, then `MODES_TIEABLE_P + (MODE1, MODE2)' should be nonzero. If they differ for any R, you + should define this macro to return zero unless some other + mechanism ensures the accessibility of the value in a narrower + mode. + + You should define this macro to return nonzero in as many cases as + possible since doing so will allow GCC to perform better register + allocation. + + -- Target Hook: bool TARGET_HARD_REGNO_SCRATCH_OK (unsigned int REGNO) + This target hook should return `true' if it is OK to use a hard + register REGNO as scratch reg in peephole2. + + One common use of this macro is to prevent using of a register that + is not saved by a prologue in an interrupt handler. + + The default version of this hook always returns `true'. + + -- Macro: AVOID_CCMODE_COPIES + Define this macro if the compiler should avoid copies to/from + `CCmode' registers. You should only define this macro if support + for copying to/from `CCmode' is incomplete. + + +File: gccint.info, Node: Leaf Functions, Next: Stack Registers, Prev: Values in Registers, Up: Registers + +17.7.4 Handling Leaf Functions +------------------------------ + +On some machines, a leaf function (i.e., one which makes no calls) can +run more efficiently if it does not make its own register window. +Often this means it is required to receive its arguments in the +registers where they are passed by the caller, instead of the registers +where they would normally arrive. + + The special treatment for leaf functions generally applies only when +other conditions are met; for example, often they may use only those +registers for its own variables and temporaries. We use the term "leaf +function" to mean a function that is suitable for this special +handling, so that functions with no calls are not necessarily "leaf +functions". + + GCC assigns register numbers before it knows whether the function is +suitable for leaf function treatment. So it needs to renumber the +registers in order to output a leaf function. The following macros +accomplish this. + + -- Macro: LEAF_REGISTERS + Name of a char vector, indexed by hard register number, which + contains 1 for a register that is allowable in a candidate for leaf + function treatment. + + If leaf function treatment involves renumbering the registers, + then the registers marked here should be the ones before + renumbering--those that GCC would ordinarily allocate. The + registers which will actually be used in the assembler code, after + renumbering, should not be marked with 1 in this vector. + + Define this macro only if the target machine offers a way to + optimize the treatment of leaf functions. + + -- Macro: LEAF_REG_REMAP (REGNO) + A C expression whose value is the register number to which REGNO + should be renumbered, when a function is treated as a leaf + function. + + If REGNO is a register number which should not appear in a leaf + function before renumbering, then the expression should yield -1, + which will cause the compiler to abort. + + Define this macro only if the target machine offers a way to + optimize the treatment of leaf functions, and registers need to be + renumbered to do this. + + `TARGET_ASM_FUNCTION_PROLOGUE' and `TARGET_ASM_FUNCTION_EPILOGUE' must +usually treat leaf functions specially. They can test the C variable +`current_function_is_leaf' which is nonzero for leaf functions. +`current_function_is_leaf' is set prior to local register allocation +and is valid for the remaining compiler passes. They can also test the +C variable `current_function_uses_only_leaf_regs' which is nonzero for +leaf functions which only use leaf registers. +`current_function_uses_only_leaf_regs' is valid after all passes that +modify the instructions have been run and is only useful if +`LEAF_REGISTERS' is defined. + + +File: gccint.info, Node: Stack Registers, Prev: Leaf Functions, Up: Registers + +17.7.5 Registers That Form a Stack +---------------------------------- + +There are special features to handle computers where some of the +"registers" form a stack. Stack registers are normally written by +pushing onto the stack, and are numbered relative to the top of the +stack. + + Currently, GCC can only handle one group of stack-like registers, and +they must be consecutively numbered. Furthermore, the existing support +for stack-like registers is specific to the 80387 floating point +coprocessor. If you have a new architecture that uses stack-like +registers, you will need to do substantial work on `reg-stack.c' and +write your machine description to cooperate with it, as well as +defining these macros. + + -- Macro: STACK_REGS + Define this if the machine has any stack-like registers. + + -- Macro: STACK_REG_COVER_CLASS + This is a cover class containing the stack registers. Define this + if the machine has any stack-like registers. + + -- Macro: FIRST_STACK_REG + The number of the first stack-like register. This one is the top + of the stack. + + -- Macro: LAST_STACK_REG + The number of the last stack-like register. This one is the + bottom of the stack. + + +File: gccint.info, Node: Register Classes, Next: Old Constraints, Prev: Registers, Up: Target Macros + +17.8 Register Classes +===================== + +On many machines, the numbered registers are not all equivalent. For +example, certain registers may not be allowed for indexed addressing; +certain registers may not be allowed in some instructions. These +machine restrictions are described to the compiler using "register +classes". + + You define a number of register classes, giving each one a name and +saying which of the registers belong to it. Then you can specify +register classes that are allowed as operands to particular instruction +patterns. + + In general, each register will belong to several classes. In fact, one +class must be named `ALL_REGS' and contain all the registers. Another +class must be named `NO_REGS' and contain no registers. Often the +union of two classes will be another class; however, this is not +required. + + One of the classes must be named `GENERAL_REGS'. There is nothing +terribly special about the name, but the operand constraint letters `r' +and `g' specify this class. If `GENERAL_REGS' is the same as +`ALL_REGS', just define it as a macro which expands to `ALL_REGS'. + + Order the classes so that if class X is contained in class Y then X +has a lower class number than Y. + + The way classes other than `GENERAL_REGS' are specified in operand +constraints is through machine-dependent operand constraint letters. +You can define such letters to correspond to various classes, then use +them in operand constraints. + + You should define a class for the union of two classes whenever some +instruction allows both classes. For example, if an instruction allows +either a floating point (coprocessor) register or a general register +for a certain operand, you should define a class `FLOAT_OR_GENERAL_REGS' +which includes both of them. Otherwise you will get suboptimal code, +or even internal compiler errors when reload cannot find a register in +the the class computed via `reg_class_subunion'. + + You must also specify certain redundant information about the register +classes: for each class, which classes contain it and which ones are +contained in it; for each pair of classes, the largest class contained +in their union. + + When a value occupying several consecutive registers is expected in a +certain class, all the registers used must belong to that class. +Therefore, register classes cannot be used to enforce a requirement for +a register pair to start with an even-numbered register. The way to +specify this requirement is with `HARD_REGNO_MODE_OK'. + + Register classes used for input-operands of bitwise-and or shift +instructions have a special requirement: each such class must have, for +each fixed-point machine mode, a subclass whose registers can transfer +that mode to or from memory. For example, on some machines, the +operations for single-byte values (`QImode') are limited to certain +registers. When this is so, each register class that is used in a +bitwise-and or shift instruction must have a subclass consisting of +registers from which single-byte values can be loaded or stored. This +is so that `PREFERRED_RELOAD_CLASS' can always have a possible value to +return. + + -- Data type: enum reg_class + An enumerated type that must be defined with all the register + class names as enumerated values. `NO_REGS' must be first. + `ALL_REGS' must be the last register class, followed by one more + enumerated value, `LIM_REG_CLASSES', which is not a register class + but rather tells how many classes there are. + + Each register class has a number, which is the value of casting + the class name to type `int'. The number serves as an index in + many of the tables described below. + + -- Macro: N_REG_CLASSES + The number of distinct register classes, defined as follows: + + #define N_REG_CLASSES (int) LIM_REG_CLASSES + + -- Macro: REG_CLASS_NAMES + An initializer containing the names of the register classes as C + string constants. These names are used in writing some of the + debugging dumps. + + -- Macro: REG_CLASS_CONTENTS + An initializer containing the contents of the register classes, as + integers which are bit masks. The Nth integer specifies the + contents of class N. The way the integer MASK is interpreted is + that register R is in the class if `MASK & (1 << R)' is 1. + + When the machine has more than 32 registers, an integer does not + suffice. Then the integers are replaced by sub-initializers, + braced groupings containing several integers. Each + sub-initializer must be suitable as an initializer for the type + `HARD_REG_SET' which is defined in `hard-reg-set.h'. In this + situation, the first integer in each sub-initializer corresponds to + registers 0 through 31, the second integer to registers 32 through + 63, and so on. + + -- Macro: REGNO_REG_CLASS (REGNO) + A C expression whose value is a register class containing hard + register REGNO. In general there is more than one such class; + choose a class which is "minimal", meaning that no smaller class + also contains the register. + + -- Macro: BASE_REG_CLASS + A macro whose definition is the name of the class to which a valid + base register must belong. A base register is one used in an + address which is the register value plus a displacement. + + -- Macro: MODE_BASE_REG_CLASS (MODE) + This is a variation of the `BASE_REG_CLASS' macro which allows the + selection of a base register in a mode dependent manner. If MODE + is VOIDmode then it should return the same value as + `BASE_REG_CLASS'. + + -- Macro: MODE_BASE_REG_REG_CLASS (MODE) + A C expression whose value is the register class to which a valid + base register must belong in order to be used in a base plus index + register address. You should define this macro if base plus index + addresses have different requirements than other base register + uses. + + -- Macro: MODE_CODE_BASE_REG_CLASS (MODE, OUTER_CODE, INDEX_CODE) + A C expression whose value is the register class to which a valid + base register must belong. OUTER_CODE and INDEX_CODE define the + context in which the base register occurs. OUTER_CODE is the code + of the immediately enclosing expression (`MEM' for the top level + of an address, `ADDRESS' for something that occurs in an + `address_operand'). INDEX_CODE is the code of the corresponding + index expression if OUTER_CODE is `PLUS'; `SCRATCH' otherwise. + + -- Macro: INDEX_REG_CLASS + A macro whose definition is the name of the class to which a valid + index register must belong. An index register is one used in an + address where its value is either multiplied by a scale factor or + added to another register (as well as added to a displacement). + + -- Macro: REGNO_OK_FOR_BASE_P (NUM) + A C expression which is nonzero if register number NUM is suitable + for use as a base register in operand addresses. + + -- Macro: REGNO_MODE_OK_FOR_BASE_P (NUM, MODE) + A C expression that is just like `REGNO_OK_FOR_BASE_P', except that + that expression may examine the mode of the memory reference in + MODE. You should define this macro if the mode of the memory + reference affects whether a register may be used as a base + register. If you define this macro, the compiler will use it + instead of `REGNO_OK_FOR_BASE_P'. The mode may be `VOIDmode' for + addresses that appear outside a `MEM', i.e., as an + `address_operand'. + + -- Macro: REGNO_MODE_OK_FOR_REG_BASE_P (NUM, MODE) + A C expression which is nonzero if register number NUM is suitable + for use as a base register in base plus index operand addresses, + accessing memory in mode MODE. It may be either a suitable hard + register or a pseudo register that has been allocated such a hard + register. You should define this macro if base plus index + addresses have different requirements than other base register + uses. + + Use of this macro is deprecated; please use the more general + `REGNO_MODE_CODE_OK_FOR_BASE_P'. + + -- Macro: REGNO_MODE_CODE_OK_FOR_BASE_P (NUM, MODE, OUTER_CODE, + INDEX_CODE) + A C expression that is just like `REGNO_MODE_OK_FOR_BASE_P', except + that that expression may examine the context in which the register + appears in the memory reference. OUTER_CODE is the code of the + immediately enclosing expression (`MEM' if at the top level of the + address, `ADDRESS' for something that occurs in an + `address_operand'). INDEX_CODE is the code of the corresponding + index expression if OUTER_CODE is `PLUS'; `SCRATCH' otherwise. + The mode may be `VOIDmode' for addresses that appear outside a + `MEM', i.e., as an `address_operand'. + + -- Macro: REGNO_OK_FOR_INDEX_P (NUM) + A C expression which is nonzero if register number NUM is suitable + for use as an index register in operand addresses. It may be + either a suitable hard register or a pseudo register that has been + allocated such a hard register. + + The difference between an index register and a base register is + that the index register may be scaled. If an address involves the + sum of two registers, neither one of them scaled, then either one + may be labeled the "base" and the other the "index"; but whichever + labeling is used must fit the machine's constraints of which + registers may serve in each capacity. The compiler will try both + labelings, looking for one that is valid, and will reload one or + both registers only if neither labeling works. + + -- Target Hook: reg_class_t TARGET_PREFERRED_RENAME_CLASS (reg_class_t + RCLASS) + A target hook that places additional preference on the register + class to use when it is necessary to rename a register in class + RCLASS to another class, or perhaps NO_REGS, if no preferred + register class is found or hook `preferred_rename_class' is not + implemented. Sometimes returning a more restrictive class makes + better code. For example, on ARM, thumb-2 instructions using + `LO_REGS' may be smaller than instructions using `GENERIC_REGS'. + By returning `LO_REGS' from `preferred_rename_class', code size + can be reduced. + + -- Target Hook: reg_class_t TARGET_PREFERRED_RELOAD_CLASS (rtx X, + reg_class_t RCLASS) + A target hook that places additional restrictions on the register + class to use when it is necessary to copy value X into a register + in class RCLASS. The value is a register class; perhaps RCLASS, + or perhaps another, smaller class. + + The default version of this hook always returns value of `rclass' + argument. + + Sometimes returning a more restrictive class makes better code. + For example, on the 68000, when X is an integer constant that is + in range for a `moveq' instruction, the value of this macro is + always `DATA_REGS' as long as RCLASS includes the data registers. + Requiring a data register guarantees that a `moveq' will be used. + + One case where `TARGET_PREFERRED_RELOAD_CLASS' must not return + RCLASS is if X is a legitimate constant which cannot be loaded + into some register class. By returning `NO_REGS' you can force X + into a memory location. For example, rs6000 can load immediate + values into general-purpose registers, but does not have an + instruction for loading an immediate value into a floating-point + register, so `TARGET_PREFERRED_RELOAD_CLASS' returns `NO_REGS' when + X is a floating-point constant. If the constant can't be loaded + into any kind of register, code generation will be better if + `LEGITIMATE_CONSTANT_P' makes the constant illegitimate instead of + using `TARGET_PREFERRED_RELOAD_CLASS'. + + If an insn has pseudos in it after register allocation, reload + will go through the alternatives and call repeatedly + `TARGET_PREFERRED_RELOAD_CLASS' to find the best one. Returning + `NO_REGS', in this case, makes reload add a `!' in front of the + constraint: the x86 back-end uses this feature to discourage usage + of 387 registers when math is done in the SSE registers (and vice + versa). + + -- Macro: PREFERRED_RELOAD_CLASS (X, CLASS) + A C expression that places additional restrictions on the register + class to use when it is necessary to copy value X into a register + in class CLASS. The value is a register class; perhaps CLASS, or + perhaps another, smaller class. On many machines, the following + definition is safe: + + #define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS + + Sometimes returning a more restrictive class makes better code. + For example, on the 68000, when X is an integer constant that is + in range for a `moveq' instruction, the value of this macro is + always `DATA_REGS' as long as CLASS includes the data registers. + Requiring a data register guarantees that a `moveq' will be used. + + One case where `PREFERRED_RELOAD_CLASS' must not return CLASS is + if X is a legitimate constant which cannot be loaded into some + register class. By returning `NO_REGS' you can force X into a + memory location. For example, rs6000 can load immediate values + into general-purpose registers, but does not have an instruction + for loading an immediate value into a floating-point register, so + `PREFERRED_RELOAD_CLASS' returns `NO_REGS' when X is a + floating-point constant. If the constant can't be loaded into any + kind of register, code generation will be better if + `LEGITIMATE_CONSTANT_P' makes the constant illegitimate instead of + using `PREFERRED_RELOAD_CLASS'. + + If an insn has pseudos in it after register allocation, reload + will go through the alternatives and call repeatedly + `PREFERRED_RELOAD_CLASS' to find the best one. Returning + `NO_REGS', in this case, makes reload add a `!' in front of the + constraint: the x86 back-end uses this feature to discourage usage + of 387 registers when math is done in the SSE registers (and vice + versa). + + -- Macro: PREFERRED_OUTPUT_RELOAD_CLASS (X, CLASS) + Like `PREFERRED_RELOAD_CLASS', but for output reloads instead of + input reloads. If you don't define this macro, the default is to + use CLASS, unchanged. + + You can also use `PREFERRED_OUTPUT_RELOAD_CLASS' to discourage + reload from using some alternatives, like `PREFERRED_RELOAD_CLASS'. + + -- Target Hook: reg_class_t TARGET_PREFERRED_OUTPUT_RELOAD_CLASS (rtx + X, reg_class_t RCLASS) + Like `TARGET_PREFERRED_RELOAD_CLASS', but for output reloads + instead of input reloads. + + The default version of this hook always returns value of `rclass' + argument. + + You can also use `TARGET_PREFERRED_OUTPUT_RELOAD_CLASS' to + discourage reload from using some alternatives, like + `TARGET_PREFERRED_RELOAD_CLASS'. + + -- Macro: LIMIT_RELOAD_CLASS (MODE, CLASS) + A C expression that places additional restrictions on the register + class to use when it is necessary to be able to hold a value of + mode MODE in a reload register for which class CLASS would + ordinarily be used. + + Unlike `PREFERRED_RELOAD_CLASS', this macro should be used when + there are certain modes that simply can't go in certain reload + classes. + + The value is a register class; perhaps CLASS, or perhaps another, + smaller class. + + Don't define this macro unless the target machine has limitations + which require the macro to do something nontrivial. + + -- Target Hook: reg_class_t TARGET_SECONDARY_RELOAD (bool IN_P, rtx X, + reg_class_t RELOAD_CLASS, enum machine_mode RELOAD_MODE, + secondary_reload_info *SRI) + Many machines have some registers that cannot be copied directly + to or from memory or even from other types of registers. An + example is the `MQ' register, which on most machines, can only be + copied to or from general registers, but not memory. Below, we + shall be using the term 'intermediate register' when a move + operation cannot be performed directly, but has to be done by + copying the source into the intermediate register first, and then + copying the intermediate register to the destination. An + intermediate register always has the same mode as source and + destination. Since it holds the actual value being copied, reload + might apply optimizations to re-use an intermediate register and + eliding the copy from the source when it can determine that the + intermediate register still holds the required value. + + Another kind of secondary reload is required on some machines which + allow copying all registers to and from memory, but require a + scratch register for stores to some memory locations (e.g., those + with symbolic address on the RT, and those with certain symbolic + address on the SPARC when compiling PIC). Scratch registers need + not have the same mode as the value being copied, and usually hold + a different value than that being copied. Special patterns in the + md file are needed to describe how the copy is performed with the + help of the scratch register; these patterns also describe the + number, register class(es) and mode(s) of the scratch register(s). + + In some cases, both an intermediate and a scratch register are + required. + + For input reloads, this target hook is called with nonzero IN_P, + and X is an rtx that needs to be copied to a register of class + RELOAD_CLASS in RELOAD_MODE. For output reloads, this target hook + is called with zero IN_P, and a register of class RELOAD_CLASS + needs to be copied to rtx X in RELOAD_MODE. + + If copying a register of RELOAD_CLASS from/to X requires an + intermediate register, the hook `secondary_reload' should return + the register class required for this intermediate register. If no + intermediate register is required, it should return NO_REGS. If + more than one intermediate register is required, describe the one + that is closest in the copy chain to the reload register. + + If scratch registers are needed, you also have to describe how to + perform the copy from/to the reload register to/from this closest + intermediate register. Or if no intermediate register is + required, but still a scratch register is needed, describe the + copy from/to the reload register to/from the reload operand X. + + You do this by setting `sri->icode' to the instruction code of a + pattern in the md file which performs the move. Operands 0 and 1 + are the output and input of this copy, respectively. Operands + from operand 2 onward are for scratch operands. These scratch + operands must have a mode, and a single-register-class output + constraint. + + When an intermediate register is used, the `secondary_reload' hook + will be called again to determine how to copy the intermediate + register to/from the reload operand X, so your hook must also have + code to handle the register class of the intermediate operand. + + X might be a pseudo-register or a `subreg' of a pseudo-register, + which could either be in a hard register or in memory. Use + `true_regnum' to find out; it will return -1 if the pseudo is in + memory and the hard register number if it is in a register. + + Scratch operands in memory (constraint `"=m"' / `"=&m"') are + currently not supported. For the time being, you will have to + continue to use `SECONDARY_MEMORY_NEEDED' for that purpose. + + `copy_cost' also uses this target hook to find out how values are + copied. If you want it to include some extra cost for the need to + allocate (a) scratch register(s), set `sri->extra_cost' to the + additional cost. Or if two dependent moves are supposed to have a + lower cost than the sum of the individual moves due to expected + fortuitous scheduling and/or special forwarding logic, you can set + `sri->extra_cost' to a negative amount. + + -- Macro: SECONDARY_RELOAD_CLASS (CLASS, MODE, X) + -- Macro: SECONDARY_INPUT_RELOAD_CLASS (CLASS, MODE, X) + -- Macro: SECONDARY_OUTPUT_RELOAD_CLASS (CLASS, MODE, X) + These macros are obsolete, new ports should use the target hook + `TARGET_SECONDARY_RELOAD' instead. + + These are obsolete macros, replaced by the + `TARGET_SECONDARY_RELOAD' target hook. Older ports still define + these macros to indicate to the reload phase that it may need to + allocate at least one register for a reload in addition to the + register to contain the data. Specifically, if copying X to a + register CLASS in MODE requires an intermediate register, you were + supposed to define `SECONDARY_INPUT_RELOAD_CLASS' to return the + largest register class all of whose registers can be used as + intermediate registers or scratch registers. + + If copying a register CLASS in MODE to X requires an intermediate + or scratch register, `SECONDARY_OUTPUT_RELOAD_CLASS' was supposed + to be defined be defined to return the largest register class + required. If the requirements for input and output reloads were + the same, the macro `SECONDARY_RELOAD_CLASS' should have been used + instead of defining both macros identically. + + The values returned by these macros are often `GENERAL_REGS'. + Return `NO_REGS' if no spare register is needed; i.e., if X can be + directly copied to or from a register of CLASS in MODE without + requiring a scratch register. Do not define this macro if it + would always return `NO_REGS'. + + If a scratch register is required (either with or without an + intermediate register), you were supposed to define patterns for + `reload_inM' or `reload_outM', as required (*note Standard + Names::. These patterns, which were normally implemented with a + `define_expand', should be similar to the `movM' patterns, except + that operand 2 is the scratch register. + + These patterns need constraints for the reload register and scratch + register that contain a single register class. If the original + reload register (whose class is CLASS) can meet the constraint + given in the pattern, the value returned by these macros is used + for the class of the scratch register. Otherwise, two additional + reload registers are required. Their classes are obtained from + the constraints in the insn pattern. + + X might be a pseudo-register or a `subreg' of a pseudo-register, + which could either be in a hard register or in memory. Use + `true_regnum' to find out; it will return -1 if the pseudo is in + memory and the hard register number if it is in a register. + + These macros should not be used in the case where a particular + class of registers can only be copied to memory and not to another + class of registers. In that case, secondary reload registers are + not needed and would not be helpful. Instead, a stack location + must be used to perform the copy and the `movM' pattern should use + memory as an intermediate storage. This case often occurs between + floating-point and general registers. + + -- Macro: SECONDARY_MEMORY_NEEDED (CLASS1, CLASS2, M) + Certain machines have the property that some registers cannot be + copied to some other registers without using memory. Define this + macro on those machines to be a C expression that is nonzero if + objects of mode M in registers of CLASS1 can only be copied to + registers of class CLASS2 by storing a register of CLASS1 into + memory and loading that memory location into a register of CLASS2. + + Do not define this macro if its value would always be zero. + + -- Macro: SECONDARY_MEMORY_NEEDED_RTX (MODE) + Normally when `SECONDARY_MEMORY_NEEDED' is defined, the compiler + allocates a stack slot for a memory location needed for register + copies. If this macro is defined, the compiler instead uses the + memory location defined by this macro. + + Do not define this macro if you do not define + `SECONDARY_MEMORY_NEEDED'. + + -- Macro: SECONDARY_MEMORY_NEEDED_MODE (MODE) + When the compiler needs a secondary memory location to copy + between two registers of mode MODE, it normally allocates + sufficient memory to hold a quantity of `BITS_PER_WORD' bits and + performs the store and load operations in a mode that many bits + wide and whose class is the same as that of MODE. + + This is right thing to do on most machines because it ensures that + all bits of the register are copied and prevents accesses to the + registers in a narrower mode, which some machines prohibit for + floating-point registers. + + However, this default behavior is not correct on some machines, + such as the DEC Alpha, that store short integers in floating-point + registers differently than in integer registers. On those + machines, the default widening will not work correctly and you + must define this macro to suppress that widening in some cases. + See the file `alpha.h' for details. + + Do not define this macro if you do not define + `SECONDARY_MEMORY_NEEDED' or if widening MODE to a mode that is + `BITS_PER_WORD' bits wide is correct for your machine. + + -- Target Hook: bool TARGET_CLASS_LIKELY_SPILLED_P (reg_class_t RCLASS) + A target hook which returns `true' if pseudos that have been + assigned to registers of class RCLASS would likely be spilled + because registers of RCLASS are needed for spill registers. + + The default version of this target hook returns `true' if RCLASS + has exactly one register and `false' otherwise. On most machines, + this default should be used. Only use this target hook to some + other expression if pseudos allocated by `local-alloc.c' end up in + memory because their hard registers were needed for spill + registers. If this target hook returns `false' for those classes, + those pseudos will only be allocated by `global.c', which knows + how to reallocate the pseudo to another register. If there would + not be another register available for reallocation, you should not + change the implementation of this target hook since the only + effect of such implementation would be to slow down register + allocation. + + -- Macro: CLASS_MAX_NREGS (CLASS, MODE) + A C expression for the maximum number of consecutive registers of + class CLASS needed to hold a value of mode MODE. + + This is closely related to the macro `HARD_REGNO_NREGS'. In fact, + the value of the macro `CLASS_MAX_NREGS (CLASS, MODE)' should be + the maximum value of `HARD_REGNO_NREGS (REGNO, MODE)' for all + REGNO values in the class CLASS. + + This macro helps control the handling of multiple-word values in + the reload pass. + + -- Macro: CANNOT_CHANGE_MODE_CLASS (FROM, TO, CLASS) + If defined, a C expression that returns nonzero for a CLASS for + which a change from mode FROM to mode TO is invalid. + + For the example, loading 32-bit integer or floating-point objects + into floating-point registers on the Alpha extends them to 64 bits. + Therefore loading a 64-bit object and then storing it as a 32-bit + object does not store the low-order 32 bits, as would be the case + for a normal register. Therefore, `alpha.h' defines + `CANNOT_CHANGE_MODE_CLASS' as below: + + #define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \ + (GET_MODE_SIZE (FROM) != GET_MODE_SIZE (TO) \ + ? reg_classes_intersect_p (FLOAT_REGS, (CLASS)) : 0) + + -- Target Hook: const reg_class_t * TARGET_IRA_COVER_CLASSES (void) + Return an array of cover classes for the Integrated Register + Allocator (IRA). Cover classes are a set of non-intersecting + register classes covering all hard registers used for register + allocation purposes. If a move between two registers in the same + cover class is possible, it should be cheaper than a load or store + of the registers. The array is terminated by a `LIM_REG_CLASSES' + element. + + The order of cover classes in the array is important. If two + classes have the same cost of usage for a pseudo, the class + occurred first in the array is chosen for the pseudo. + + This hook is called once at compiler startup, after the + command-line options have been processed. It is then re-examined + by every call to `target_reinit'. + + The default implementation returns `IRA_COVER_CLASSES', if defined, + otherwise there is no default implementation. You must define + either this macro or `IRA_COVER_CLASSES' in order to use the + integrated register allocator with Chaitin-Briggs coloring. If the + macro is not defined, the only available coloring algorithm is + Chow's priority coloring. + + This hook must not be modified from `NULL' to non-`NULL' or vice + versa by command-line option processing. + + -- Macro: IRA_COVER_CLASSES + See the documentation for `TARGET_IRA_COVER_CLASSES'. + + +File: gccint.info, Node: Old Constraints, Next: Stack and Calling, Prev: Register Classes, Up: Target Macros + +17.9 Obsolete Macros for Defining Constraints +============================================= + +Machine-specific constraints can be defined with these macros instead +of the machine description constructs described in *note Define +Constraints::. This mechanism is obsolete. New ports should not use +it; old ports should convert to the new mechanism. + + -- Macro: CONSTRAINT_LEN (CHAR, STR) + For the constraint at the start of STR, which starts with the + letter C, return the length. This allows you to have register + class / constant / extra constraints that are longer than a single + letter; you don't need to define this macro if you can do with + single-letter constraints only. The definition of this macro + should use DEFAULT_CONSTRAINT_LEN for all the characters that you + don't want to handle specially. There are some sanity checks in + genoutput.c that check the constraint lengths for the md file, so + you can also use this macro to help you while you are + transitioning from a byzantine single-letter-constraint scheme: + when you return a negative length for a constraint you want to + re-use, genoutput will complain about every instance where it is + used in the md file. + + -- Macro: REG_CLASS_FROM_LETTER (CHAR) + A C expression which defines the machine-dependent operand + constraint letters for register classes. If CHAR is such a + letter, the value should be the register class corresponding to + it. Otherwise, the value should be `NO_REGS'. The register + letter `r', corresponding to class `GENERAL_REGS', will not be + passed to this macro; you do not need to handle it. + + -- Macro: REG_CLASS_FROM_CONSTRAINT (CHAR, STR) + Like `REG_CLASS_FROM_LETTER', but you also get the constraint + string passed in STR, so that you can use suffixes to distinguish + between different variants. + + -- Macro: CONST_OK_FOR_LETTER_P (VALUE, C) + A C expression that defines the machine-dependent operand + constraint letters (`I', `J', `K', ... `P') that specify + particular ranges of integer values. If C is one of those + letters, the expression should check that VALUE, an integer, is in + the appropriate range and return 1 if so, 0 otherwise. If C is + not one of those letters, the value should be 0 regardless of + VALUE. + + -- Macro: CONST_OK_FOR_CONSTRAINT_P (VALUE, C, STR) + Like `CONST_OK_FOR_LETTER_P', but you also get the constraint + string passed in STR, so that you can use suffixes to distinguish + between different variants. + + -- Macro: CONST_DOUBLE_OK_FOR_LETTER_P (VALUE, C) + A C expression that defines the machine-dependent operand + constraint letters that specify particular ranges of + `const_double' values (`G' or `H'). + + If C is one of those letters, the expression should check that + VALUE, an RTX of code `const_double', is in the appropriate range + and return 1 if so, 0 otherwise. If C is not one of those + letters, the value should be 0 regardless of VALUE. + + `const_double' is used for all floating-point constants and for + `DImode' fixed-point constants. A given letter can accept either + or both kinds of values. It can use `GET_MODE' to distinguish + between these kinds. + + -- Macro: CONST_DOUBLE_OK_FOR_CONSTRAINT_P (VALUE, C, STR) + Like `CONST_DOUBLE_OK_FOR_LETTER_P', but you also get the + constraint string passed in STR, so that you can use suffixes to + distinguish between different variants. + + -- Macro: EXTRA_CONSTRAINT (VALUE, C) + A C expression that defines the optional machine-dependent + constraint letters that can be used to segregate specific types of + operands, usually memory references, for the target machine. Any + letter that is not elsewhere defined and not matched by + `REG_CLASS_FROM_LETTER' / `REG_CLASS_FROM_CONSTRAINT' may be used. + Normally this macro will not be defined. + + If it is required for a particular target machine, it should + return 1 if VALUE corresponds to the operand type represented by + the constraint letter C. If C is not defined as an extra + constraint, the value returned should be 0 regardless of VALUE. + + For example, on the ROMP, load instructions cannot have their + output in r0 if the memory reference contains a symbolic address. + Constraint letter `Q' is defined as representing a memory address + that does _not_ contain a symbolic address. An alternative is + specified with a `Q' constraint on the input and `r' on the + output. The next alternative specifies `m' on the input and a + register class that does not include r0 on the output. + + -- Macro: EXTRA_CONSTRAINT_STR (VALUE, C, STR) + Like `EXTRA_CONSTRAINT', but you also get the constraint string + passed in STR, so that you can use suffixes to distinguish between + different variants. + + -- Macro: EXTRA_MEMORY_CONSTRAINT (C, STR) + A C expression that defines the optional machine-dependent + constraint letters, amongst those accepted by `EXTRA_CONSTRAINT', + that should be treated like memory constraints by the reload pass. + + It should return 1 if the operand type represented by the + constraint at the start of STR, the first letter of which is the + letter C, comprises a subset of all memory references including + all those whose address is simply a base register. This allows + the reload pass to reload an operand, if it does not directly + correspond to the operand type of C, by copying its address into a + base register. + + For example, on the S/390, some instructions do not accept + arbitrary memory references, but only those that do not make use + of an index register. The constraint letter `Q' is defined via + `EXTRA_CONSTRAINT' as representing a memory address of this type. + If the letter `Q' is marked as `EXTRA_MEMORY_CONSTRAINT', a `Q' + constraint can handle any memory operand, because the reload pass + knows it can be reloaded by copying the memory address into a base + register if required. This is analogous to the way an `o' + constraint can handle any memory operand. + + -- Macro: EXTRA_ADDRESS_CONSTRAINT (C, STR) + A C expression that defines the optional machine-dependent + constraint letters, amongst those accepted by `EXTRA_CONSTRAINT' / + `EXTRA_CONSTRAINT_STR', that should be treated like address + constraints by the reload pass. + + It should return 1 if the operand type represented by the + constraint at the start of STR, which starts with the letter C, + comprises a subset of all memory addresses including all those + that consist of just a base register. This allows the reload pass + to reload an operand, if it does not directly correspond to the + operand type of STR, by copying it into a base register. + + Any constraint marked as `EXTRA_ADDRESS_CONSTRAINT' can only be + used with the `address_operand' predicate. It is treated + analogously to the `p' constraint. + + +File: gccint.info, Node: Stack and Calling, Next: Varargs, Prev: Old Constraints, Up: Target Macros + +17.10 Stack Layout and Calling Conventions +========================================== + +This describes the stack layout and calling conventions. + +* Menu: + +* Frame Layout:: +* Exception Handling:: +* Stack Checking:: +* Frame Registers:: +* Elimination:: +* Stack Arguments:: +* Register Arguments:: +* Scalar Return:: +* Aggregate Return:: +* Caller Saves:: +* Function Entry:: +* Profiling:: +* Tail Calls:: +* Stack Smashing Protection:: + + +File: gccint.info, Node: Frame Layout, Next: Exception Handling, Up: Stack and Calling + +17.10.1 Basic Stack Layout +-------------------------- + +Here is the basic stack layout. + + -- Macro: STACK_GROWS_DOWNWARD + Define this macro if pushing a word onto the stack moves the stack + pointer to a smaller address. + + When we say, "define this macro if ...", it means that the + compiler checks this macro only with `#ifdef' so the precise + definition used does not matter. + + -- Macro: STACK_PUSH_CODE + This macro defines the operation used when something is pushed on + the stack. In RTL, a push operation will be `(set (mem + (STACK_PUSH_CODE (reg sp))) ...)' + + The choices are `PRE_DEC', `POST_DEC', `PRE_INC', and `POST_INC'. + Which of these is correct depends on the stack direction and on + whether the stack pointer points to the last item on the stack or + whether it points to the space for the next item on the stack. + + The default is `PRE_DEC' when `STACK_GROWS_DOWNWARD' is defined, + which is almost always right, and `PRE_INC' otherwise, which is + often wrong. + + -- Macro: FRAME_GROWS_DOWNWARD + Define this macro to nonzero value if the addresses of local + variable slots are at negative offsets from the frame pointer. + + -- Macro: ARGS_GROW_DOWNWARD + Define this macro if successive arguments to a function occupy + decreasing addresses on the stack. + + -- Macro: STARTING_FRAME_OFFSET + Offset from the frame pointer to the first local variable slot to + be allocated. + + If `FRAME_GROWS_DOWNWARD', find the next slot's offset by + subtracting the first slot's length from `STARTING_FRAME_OFFSET'. + Otherwise, it is found by adding the length of the first slot to + the value `STARTING_FRAME_OFFSET'. + + -- Macro: STACK_ALIGNMENT_NEEDED + Define to zero to disable final alignment of the stack during + reload. The nonzero default for this macro is suitable for most + ports. + + On ports where `STARTING_FRAME_OFFSET' is nonzero or where there + is a register save block following the local block that doesn't + require alignment to `STACK_BOUNDARY', it may be beneficial to + disable stack alignment and do it in the backend. + + -- Macro: STACK_POINTER_OFFSET + Offset from the stack pointer register to the first location at + which outgoing arguments are placed. If not specified, the + default value of zero is used. This is the proper value for most + machines. + + If `ARGS_GROW_DOWNWARD', this is the offset to the location above + the first location at which outgoing arguments are placed. + + -- Macro: FIRST_PARM_OFFSET (FUNDECL) + Offset from the argument pointer register to the first argument's + address. On some machines it may depend on the data type of the + function. + + If `ARGS_GROW_DOWNWARD', this is the offset to the location above + the first argument's address. + + -- Macro: STACK_DYNAMIC_OFFSET (FUNDECL) + Offset from the stack pointer register to an item dynamically + allocated on the stack, e.g., by `alloca'. + + The default value for this macro is `STACK_POINTER_OFFSET' plus the + length of the outgoing arguments. The default is correct for most + machines. See `function.c' for details. + + -- Macro: INITIAL_FRAME_ADDRESS_RTX + A C expression whose value is RTL representing the address of the + initial stack frame. This address is passed to `RETURN_ADDR_RTX' + and `DYNAMIC_CHAIN_ADDRESS'. If you don't define this macro, a + reasonable default value will be used. Define this macro in order + to make frame pointer elimination work in the presence of + `__builtin_frame_address (count)' and `__builtin_return_address + (count)' for `count' not equal to zero. + + -- Macro: DYNAMIC_CHAIN_ADDRESS (FRAMEADDR) + A C expression whose value is RTL representing the address in a + stack frame where the pointer to the caller's frame is stored. + Assume that FRAMEADDR is an RTL expression for the address of the + stack frame itself. + + If you don't define this macro, the default is to return the value + of FRAMEADDR--that is, the stack frame address is also the address + of the stack word that points to the previous frame. + + -- Macro: SETUP_FRAME_ADDRESSES + If defined, a C expression that produces the machine-specific code + to setup the stack so that arbitrary frames can be accessed. For + example, on the SPARC, we must flush all of the register windows + to the stack before we can access arbitrary stack frames. You + will seldom need to define this macro. + + -- Target Hook: rtx TARGET_BUILTIN_SETJMP_FRAME_VALUE (void) + This target hook should return an rtx that is used to store the + address of the current frame into the built in `setjmp' buffer. + The default value, `virtual_stack_vars_rtx', is correct for most + machines. One reason you may need to define this target hook is if + `hard_frame_pointer_rtx' is the appropriate value on your machine. + + -- Macro: FRAME_ADDR_RTX (FRAMEADDR) + A C expression whose value is RTL representing the value of the + frame address for the current frame. FRAMEADDR is the frame + pointer of the current frame. This is used for + __builtin_frame_address. You need only define this macro if the + frame address is not the same as the frame pointer. Most machines + do not need to define it. + + -- Macro: RETURN_ADDR_RTX (COUNT, FRAMEADDR) + A C expression whose value is RTL representing the value of the + return address for the frame COUNT steps up from the current + frame, after the prologue. FRAMEADDR is the frame pointer of the + COUNT frame, or the frame pointer of the COUNT - 1 frame if + `RETURN_ADDR_IN_PREVIOUS_FRAME' is defined. + + The value of the expression must always be the correct address when + COUNT is zero, but may be `NULL_RTX' if there is no way to + determine the return address of other frames. + + -- Macro: RETURN_ADDR_IN_PREVIOUS_FRAME + Define this if the return address of a particular stack frame is + accessed from the frame pointer of the previous stack frame. + + -- Macro: INCOMING_RETURN_ADDR_RTX + A C expression whose value is RTL representing the location of the + incoming return address at the beginning of any function, before + the prologue. This RTL is either a `REG', indicating that the + return value is saved in `REG', or a `MEM' representing a location + in the stack. + + You only need to define this macro if you want to support call + frame debugging information like that provided by DWARF 2. + + If this RTL is a `REG', you should also define + `DWARF_FRAME_RETURN_COLUMN' to `DWARF_FRAME_REGNUM (REGNO)'. + + -- Macro: DWARF_ALT_FRAME_RETURN_COLUMN + A C expression whose value is an integer giving a DWARF 2 column + number that may be used as an alternative return column. The + column must not correspond to any gcc hard register (that is, it + must not be in the range of `DWARF_FRAME_REGNUM'). + + This macro can be useful if `DWARF_FRAME_RETURN_COLUMN' is set to a + general register, but an alternative column needs to be used for + signal frames. Some targets have also used different frame return + columns over time. + + -- Macro: DWARF_ZERO_REG + A C expression whose value is an integer giving a DWARF 2 register + number that is considered to always have the value zero. This + should only be defined if the target has an architected zero + register, and someone decided it was a good idea to use that + register number to terminate the stack backtrace. New ports + should avoid this. + + -- Target Hook: void TARGET_DWARF_HANDLE_FRAME_UNSPEC (const char + *LABEL, rtx PATTERN, int INDEX) + This target hook allows the backend to emit frame-related insns + that contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame + debugging info engine will invoke it on insns of the form + (set (reg) (unspec [...] UNSPEC_INDEX)) + and + (set (reg) (unspec_volatile [...] UNSPECV_INDEX)). + to let the backend emit the call frame instructions. LABEL is the + CFI label attached to the insn, PATTERN is the pattern of the insn + and INDEX is `UNSPEC_INDEX' or `UNSPECV_INDEX'. + + -- Macro: INCOMING_FRAME_SP_OFFSET + A C expression whose value is an integer giving the offset, in + bytes, from the value of the stack pointer register to the top of + the stack frame at the beginning of any function, before the + prologue. The top of the frame is defined to be the value of the + stack pointer in the previous frame, just before the call + instruction. + + You only need to define this macro if you want to support call + frame debugging information like that provided by DWARF 2. + + -- Macro: ARG_POINTER_CFA_OFFSET (FUNDECL) + A C expression whose value is an integer giving the offset, in + bytes, from the argument pointer to the canonical frame address + (cfa). The final value should coincide with that calculated by + `INCOMING_FRAME_SP_OFFSET'. Which is unfortunately not usable + during virtual register instantiation. + + The default value for this macro is `FIRST_PARM_OFFSET (fundecl) + + crtl->args.pretend_args_size', which is correct for most machines; + in general, the arguments are found immediately before the stack + frame. Note that this is not the case on some targets that save + registers into the caller's frame, such as SPARC and rs6000, and + so such targets need to define this macro. + + You only need to define this macro if the default is incorrect, + and you want to support call frame debugging information like that + provided by DWARF 2. + + -- Macro: FRAME_POINTER_CFA_OFFSET (FUNDECL) + If defined, a C expression whose value is an integer giving the + offset in bytes from the frame pointer to the canonical frame + address (cfa). The final value should coincide with that + calculated by `INCOMING_FRAME_SP_OFFSET'. + + Normally the CFA is calculated as an offset from the argument + pointer, via `ARG_POINTER_CFA_OFFSET', but if the argument pointer + is variable due to the ABI, this may not be possible. If this + macro is defined, it implies that the virtual register + instantiation should be based on the frame pointer instead of the + argument pointer. Only one of `FRAME_POINTER_CFA_OFFSET' and + `ARG_POINTER_CFA_OFFSET' should be defined. + + -- Macro: CFA_FRAME_BASE_OFFSET (FUNDECL) + If defined, a C expression whose value is an integer giving the + offset in bytes from the canonical frame address (cfa) to the + frame base used in DWARF 2 debug information. The default is + zero. A different value may reduce the size of debug information + on some ports. + + +File: gccint.info, Node: Exception Handling, Next: Stack Checking, Prev: Frame Layout, Up: Stack and Calling + +17.10.2 Exception Handling Support +---------------------------------- + + -- Macro: EH_RETURN_DATA_REGNO (N) + A C expression whose value is the Nth register number used for + data by exception handlers, or `INVALID_REGNUM' if fewer than N + registers are usable. + + The exception handling library routines communicate with the + exception handlers via a set of agreed upon registers. Ideally + these registers should be call-clobbered; it is possible to use + call-saved registers, but may negatively impact code size. The + target must support at least 2 data registers, but should define 4 + if there are enough free registers. + + You must define this macro if you want to support call frame + exception handling like that provided by DWARF 2. + + -- Macro: EH_RETURN_STACKADJ_RTX + A C expression whose value is RTL representing a location in which + to store a stack adjustment to be applied before function return. + This is used to unwind the stack to an exception handler's call + frame. It will be assigned zero on code paths that return + normally. + + Typically this is a call-clobbered hard register that is otherwise + untouched by the epilogue, but could also be a stack slot. + + Do not define this macro if the stack pointer is saved and restored + by the regular prolog and epilog code in the call frame itself; in + this case, the exception handling library routines will update the + stack location to be restored in place. Otherwise, you must define + this macro if you want to support call frame exception handling + like that provided by DWARF 2. + + -- Macro: EH_RETURN_HANDLER_RTX + A C expression whose value is RTL representing a location in which + to store the address of an exception handler to which we should + return. It will not be assigned on code paths that return + normally. + + Typically this is the location in the call frame at which the + normal return address is stored. For targets that return by + popping an address off the stack, this might be a memory address + just below the _target_ call frame rather than inside the current + call frame. If defined, `EH_RETURN_STACKADJ_RTX' will have already + been assigned, so it may be used to calculate the location of the + target call frame. + + Some targets have more complex requirements than storing to an + address calculable during initial code generation. In that case + the `eh_return' instruction pattern should be used instead. + + If you want to support call frame exception handling, you must + define either this macro or the `eh_return' instruction pattern. + + -- Macro: RETURN_ADDR_OFFSET + If defined, an integer-valued C expression for which rtl will be + generated to add it to the exception handler address before it is + searched in the exception handling tables, and to subtract it + again from the address before using it to return to the exception + handler. + + -- Macro: ASM_PREFERRED_EH_DATA_FORMAT (CODE, GLOBAL) + This macro chooses the encoding of pointers embedded in the + exception handling sections. If at all possible, this should be + defined such that the exception handling section will not require + dynamic relocations, and so may be read-only. + + CODE is 0 for data, 1 for code labels, 2 for function pointers. + GLOBAL is true if the symbol may be affected by dynamic + relocations. The macro should return a combination of the + `DW_EH_PE_*' defines as found in `dwarf2.h'. + + If this macro is not defined, pointers will not be encoded but + represented directly. + + -- Macro: ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (FILE, ENCODING, SIZE, + ADDR, DONE) + This macro allows the target to emit whatever special magic is + required to represent the encoding chosen by + `ASM_PREFERRED_EH_DATA_FORMAT'. Generic code takes care of + pc-relative and indirect encodings; this must be defined if the + target uses text-relative or data-relative encodings. + + This is a C statement that branches to DONE if the format was + handled. ENCODING is the format chosen, SIZE is the number of + bytes that the format occupies, ADDR is the `SYMBOL_REF' to be + emitted. + + -- Macro: MD_UNWIND_SUPPORT + A string specifying a file to be #include'd in unwind-dw2.c. The + file so included typically defines `MD_FALLBACK_FRAME_STATE_FOR'. + + -- Macro: MD_FALLBACK_FRAME_STATE_FOR (CONTEXT, FS) + This macro allows the target to add CPU and operating system + specific code to the call-frame unwinder for use when there is no + unwind data available. The most common reason to implement this + macro is to unwind through signal frames. + + This macro is called from `uw_frame_state_for' in `unwind-dw2.c', + `unwind-dw2-xtensa.c' and `unwind-ia64.c'. CONTEXT is an + `_Unwind_Context'; FS is an `_Unwind_FrameState'. Examine + `context->ra' for the address of the code being executed and + `context->cfa' for the stack pointer value. If the frame can be + decoded, the register save addresses should be updated in FS and + the macro should evaluate to `_URC_NO_REASON'. If the frame + cannot be decoded, the macro should evaluate to + `_URC_END_OF_STACK'. + + For proper signal handling in Java this macro is accompanied by + `MAKE_THROW_FRAME', defined in `libjava/include/*-signal.h' + headers. + + -- Macro: MD_HANDLE_UNWABI (CONTEXT, FS) + This macro allows the target to add operating system specific code + to the call-frame unwinder to handle the IA-64 `.unwabi' unwinding + directive, usually used for signal or interrupt frames. + + This macro is called from `uw_update_context' in `unwind-ia64.c'. + CONTEXT is an `_Unwind_Context'; FS is an `_Unwind_FrameState'. + Examine `fs->unwabi' for the abi and context in the `.unwabi' + directive. If the `.unwabi' directive can be handled, the + register save addresses should be updated in FS. + + -- Macro: TARGET_USES_WEAK_UNWIND_INFO + A C expression that evaluates to true if the target requires unwind + info to be given comdat linkage. Define it to be `1' if comdat + linkage is necessary. The default is `0'. + + +File: gccint.info, Node: Stack Checking, Next: Frame Registers, Prev: Exception Handling, Up: Stack and Calling + +17.10.3 Specifying How Stack Checking is Done +--------------------------------------------- + +GCC will check that stack references are within the boundaries of the +stack, if the option `-fstack-check' is specified, in one of three ways: + + 1. If the value of the `STACK_CHECK_BUILTIN' macro is nonzero, GCC + will assume that you have arranged for full stack checking to be + done at appropriate places in the configuration files. GCC will + not do other special processing. + + 2. If `STACK_CHECK_BUILTIN' is zero and the value of the + `STACK_CHECK_STATIC_BUILTIN' macro is nonzero, GCC will assume + that you have arranged for static stack checking (checking of the + static stack frame of functions) to be done at appropriate places + in the configuration files. GCC will only emit code to do dynamic + stack checking (checking on dynamic stack allocations) using the + third approach below. + + 3. If neither of the above are true, GCC will generate code to + periodically "probe" the stack pointer using the values of the + macros defined below. + + If neither STACK_CHECK_BUILTIN nor STACK_CHECK_STATIC_BUILTIN is +defined, GCC will change its allocation strategy for large objects if +the option `-fstack-check' is specified: they will always be allocated +dynamically if their size exceeds `STACK_CHECK_MAX_VAR_SIZE' bytes. + + -- Macro: STACK_CHECK_BUILTIN + A nonzero value if stack checking is done by the configuration + files in a machine-dependent manner. You should define this macro + if stack checking is required by the ABI of your machine or if you + would like to do stack checking in some more efficient way than + the generic approach. The default value of this macro is zero. + + -- Macro: STACK_CHECK_STATIC_BUILTIN + A nonzero value if static stack checking is done by the + configuration files in a machine-dependent manner. You should + define this macro if you would like to do static stack checking in + some more efficient way than the generic approach. The default + value of this macro is zero. + + -- Macro: STACK_CHECK_PROBE_INTERVAL_EXP + An integer specifying the interval at which GCC must generate + stack probe instructions, defined as 2 raised to this integer. + You will normally define this macro so that the interval be no + larger than the size of the "guard pages" at the end of a stack + area. The default value of 12 (4096-byte interval) is suitable + for most systems. + + -- Macro: STACK_CHECK_MOVING_SP + An integer which is nonzero if GCC should move the stack pointer + page by page when doing probes. This can be necessary on systems + where the stack pointer contains the bottom address of the memory + area accessible to the executing thread at any point in time. In + this situation an alternate signal stack is required in order to + be able to recover from a stack overflow. The default value of + this macro is zero. + + -- Macro: STACK_CHECK_PROTECT + The number of bytes of stack needed to recover from a stack + overflow, for languages where such a recovery is supported. The + default value of 75 words with the `setjmp'/`longjmp'-based + exception handling mechanism and 8192 bytes with other exception + handling mechanisms should be adequate for most machines. + + The following macros are relevant only if neither STACK_CHECK_BUILTIN +nor STACK_CHECK_STATIC_BUILTIN is defined; you can omit them altogether +in the opposite case. + + -- Macro: STACK_CHECK_MAX_FRAME_SIZE + The maximum size of a stack frame, in bytes. GCC will generate + probe instructions in non-leaf functions to ensure at least this + many bytes of stack are available. If a stack frame is larger + than this size, stack checking will not be reliable and GCC will + issue a warning. The default is chosen so that GCC only generates + one instruction on most systems. You should normally not change + the default value of this macro. + + -- Macro: STACK_CHECK_FIXED_FRAME_SIZE + GCC uses this value to generate the above warning message. It + represents the amount of fixed frame used by a function, not + including space for any callee-saved registers, temporaries and + user variables. You need only specify an upper bound for this + amount and will normally use the default of four words. + + -- Macro: STACK_CHECK_MAX_VAR_SIZE + The maximum size, in bytes, of an object that GCC will place in the + fixed area of the stack frame when the user specifies + `-fstack-check'. GCC computed the default from the values of the + above macros and you will normally not need to override that + default. + + +File: gccint.info, Node: Frame Registers, Next: Elimination, Prev: Stack Checking, Up: Stack and Calling + +17.10.4 Registers That Address the Stack Frame +---------------------------------------------- + +This discusses registers that address the stack frame. + + -- Macro: STACK_POINTER_REGNUM + The register number of the stack pointer register, which must also + be a fixed register according to `FIXED_REGISTERS'. On most + machines, the hardware determines which register this is. + + -- Macro: FRAME_POINTER_REGNUM + The register number of the frame pointer register, which is used to + access automatic variables in the stack frame. On some machines, + the hardware determines which register this is. On other + machines, you can choose any register you wish for this purpose. + + -- Macro: HARD_FRAME_POINTER_REGNUM + On some machines the offset between the frame pointer and starting + offset of the automatic variables is not known until after register + allocation has been done (for example, because the saved registers + are between these two locations). On those machines, define + `FRAME_POINTER_REGNUM' the number of a special, fixed register to + be used internally until the offset is known, and define + `HARD_FRAME_POINTER_REGNUM' to be the actual hard register number + used for the frame pointer. + + You should define this macro only in the very rare circumstances + when it is not possible to calculate the offset between the frame + pointer and the automatic variables until after register + allocation has been completed. When this macro is defined, you + must also indicate in your definition of `ELIMINABLE_REGS' how to + eliminate `FRAME_POINTER_REGNUM' into either + `HARD_FRAME_POINTER_REGNUM' or `STACK_POINTER_REGNUM'. + + Do not define this macro if it would be the same as + `FRAME_POINTER_REGNUM'. + + -- Macro: ARG_POINTER_REGNUM + The register number of the arg pointer register, which is used to + access the function's argument list. On some machines, this is + the same as the frame pointer register. On some machines, the + hardware determines which register this is. On other machines, + you can choose any register you wish for this purpose. If this is + not the same register as the frame pointer register, then you must + mark it as a fixed register according to `FIXED_REGISTERS', or + arrange to be able to eliminate it (*note Elimination::). + + -- Macro: HARD_FRAME_POINTER_IS_FRAME_POINTER + Define this to a preprocessor constant that is nonzero if + `hard_frame_pointer_rtx' and `frame_pointer_rtx' should be the + same. The default definition is `(HARD_FRAME_POINTER_REGNUM == + FRAME_POINTER_REGNUM)'; you only need to define this macro if that + definition is not suitable for use in preprocessor conditionals. + + -- Macro: HARD_FRAME_POINTER_IS_ARG_POINTER + Define this to a preprocessor constant that is nonzero if + `hard_frame_pointer_rtx' and `arg_pointer_rtx' should be the same. + The default definition is `(HARD_FRAME_POINTER_REGNUM == + ARG_POINTER_REGNUM)'; you only need to define this macro if that + definition is not suitable for use in preprocessor conditionals. + + -- Macro: RETURN_ADDRESS_POINTER_REGNUM + The register number of the return address pointer register, which + is used to access the current function's return address from the + stack. On some machines, the return address is not at a fixed + offset from the frame pointer or stack pointer or argument + pointer. This register can be defined to point to the return + address on the stack, and then be converted by `ELIMINABLE_REGS' + into either the frame pointer or stack pointer. + + Do not define this macro unless there is no other way to get the + return address from the stack. + + -- Macro: STATIC_CHAIN_REGNUM + -- Macro: STATIC_CHAIN_INCOMING_REGNUM + Register numbers used for passing a function's static chain + pointer. If register windows are used, the register number as + seen by the called function is `STATIC_CHAIN_INCOMING_REGNUM', + while the register number as seen by the calling function is + `STATIC_CHAIN_REGNUM'. If these registers are the same, + `STATIC_CHAIN_INCOMING_REGNUM' need not be defined. + + The static chain register need not be a fixed register. + + If the static chain is passed in memory, these macros should not be + defined; instead, the `TARGET_STATIC_CHAIN' hook should be used. + + -- Target Hook: rtx TARGET_STATIC_CHAIN (const_tree FNDECL, bool + INCOMING_P) + This hook replaces the use of `STATIC_CHAIN_REGNUM' et al for + targets that may use different static chain locations for different + nested functions. This may be required if the target has function + attributes that affect the calling conventions of the function and + those calling conventions use different static chain locations. + + The default version of this hook uses `STATIC_CHAIN_REGNUM' et al. + + If the static chain is passed in memory, this hook should be used + to provide rtx giving `mem' expressions that denote where they are + stored. Often the `mem' expression as seen by the caller will be + at an offset from the stack pointer and the `mem' expression as + seen by the callee will be at an offset from the frame pointer. The + variables `stack_pointer_rtx', `frame_pointer_rtx', and + `arg_pointer_rtx' will have been initialized and should be used to + refer to those items. + + -- Macro: DWARF_FRAME_REGISTERS + This macro specifies the maximum number of hard registers that can + be saved in a call frame. This is used to size data structures + used in DWARF2 exception handling. + + Prior to GCC 3.0, this macro was needed in order to establish a + stable exception handling ABI in the face of adding new hard + registers for ISA extensions. In GCC 3.0 and later, the EH ABI is + insulated from changes in the number of hard registers. + Nevertheless, this macro can still be used to reduce the runtime + memory requirements of the exception handling routines, which can + be substantial if the ISA contains a lot of registers that are not + call-saved. + + If this macro is not defined, it defaults to + `FIRST_PSEUDO_REGISTER'. + + -- Macro: PRE_GCC3_DWARF_FRAME_REGISTERS + This macro is similar to `DWARF_FRAME_REGISTERS', but is provided + for backward compatibility in pre GCC 3.0 compiled code. + + If this macro is not defined, it defaults to + `DWARF_FRAME_REGISTERS'. + + -- Macro: DWARF_REG_TO_UNWIND_COLUMN (REGNO) + Define this macro if the target's representation for dwarf + registers is different than the internal representation for unwind + column. Given a dwarf register, this macro should return the + internal unwind column number to use instead. + + See the PowerPC's SPE target for an example. + + -- Macro: DWARF_FRAME_REGNUM (REGNO) + Define this macro if the target's representation for dwarf + registers used in .eh_frame or .debug_frame is different from that + used in other debug info sections. Given a GCC hard register + number, this macro should return the .eh_frame register number. + The default is `DBX_REGISTER_NUMBER (REGNO)'. + + + -- Macro: DWARF2_FRAME_REG_OUT (REGNO, FOR_EH) + Define this macro to map register numbers held in the call frame + info that GCC has collected using `DWARF_FRAME_REGNUM' to those + that should be output in .debug_frame (`FOR_EH' is zero) and + .eh_frame (`FOR_EH' is nonzero). The default is to return `REGNO'. + + + +File: gccint.info, Node: Elimination, Next: Stack Arguments, Prev: Frame Registers, Up: Stack and Calling + +17.10.5 Eliminating Frame Pointer and Arg Pointer +------------------------------------------------- + +This is about eliminating the frame pointer and arg pointer. + + -- Target Hook: bool TARGET_FRAME_POINTER_REQUIRED (void) + This target hook should return `true' if a function must have and + use a frame pointer. This target hook is called in the reload + pass. If its return value is `true' the function will have a + frame pointer. + + This target hook can in principle examine the current function and + decide according to the facts, but on most machines the constant + `false' or the constant `true' suffices. Use `false' when the + machine allows code to be generated with no frame pointer, and + doing so saves some time or space. Use `true' when there is no + possible advantage to avoiding a frame pointer. + + In certain cases, the compiler does not know how to produce valid + code without a frame pointer. The compiler recognizes those cases + and automatically gives the function a frame pointer regardless of + what `TARGET_FRAME_POINTER_REQUIRED' returns. You don't need to + worry about them. + + In a function that does not require a frame pointer, the frame + pointer register can be allocated for ordinary usage, unless you + mark it as a fixed register. See `FIXED_REGISTERS' for more + information. + + Default return value is `false'. + + -- Macro: INITIAL_FRAME_POINTER_OFFSET (DEPTH-VAR) + A C statement to store in the variable DEPTH-VAR the difference + between the frame pointer and the stack pointer values immediately + after the function prologue. The value would be computed from + information such as the result of `get_frame_size ()' and the + tables of registers `regs_ever_live' and `call_used_regs'. + + If `ELIMINABLE_REGS' is defined, this macro will be not be used and + need not be defined. Otherwise, it must be defined even if + `TARGET_FRAME_POINTER_REQUIRED' always returns true; in that case, + you may set DEPTH-VAR to anything. + + -- Macro: ELIMINABLE_REGS + If defined, this macro specifies a table of register pairs used to + eliminate unneeded registers that point into the stack frame. If + it is not defined, the only elimination attempted by the compiler + is to replace references to the frame pointer with references to + the stack pointer. + + The definition of this macro is a list of structure + initializations, each of which specifies an original and + replacement register. + + On some machines, the position of the argument pointer is not + known until the compilation is completed. In such a case, a + separate hard register must be used for the argument pointer. + This register can be eliminated by replacing it with either the + frame pointer or the argument pointer, depending on whether or not + the frame pointer has been eliminated. + + In this case, you might specify: + #define ELIMINABLE_REGS \ + {{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM}, \ + {ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM}, \ + {FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM}} + + Note that the elimination of the argument pointer with the stack + pointer is specified first since that is the preferred elimination. + + -- Target Hook: bool TARGET_CAN_ELIMINATE (const int FROM_REG, const + int TO_REG) + This target hook should returns `true' if the compiler is allowed + to try to replace register number FROM_REG with register number + TO_REG. This target hook need only be defined if `ELIMINABLE_REGS' + is defined, and will usually be `true', since most of the cases + preventing register elimination are things that the compiler + already knows about. + + Default return value is `true'. + + -- Macro: INITIAL_ELIMINATION_OFFSET (FROM-REG, TO-REG, OFFSET-VAR) + This macro is similar to `INITIAL_FRAME_POINTER_OFFSET'. It + specifies the initial difference between the specified pair of + registers. This macro must be defined if `ELIMINABLE_REGS' is + defined. + + +File: gccint.info, Node: Stack Arguments, Next: Register Arguments, Prev: Elimination, Up: Stack and Calling + +17.10.6 Passing Function Arguments on the Stack +----------------------------------------------- + +The macros in this section control how arguments are passed on the +stack. See the following section for other macros that control passing +certain arguments in registers. + + -- Target Hook: bool TARGET_PROMOTE_PROTOTYPES (const_tree FNTYPE) + This target hook returns `true' if an argument declared in a + prototype as an integral type smaller than `int' should actually be + passed as an `int'. In addition to avoiding errors in certain + cases of mismatch, it also makes for better code on certain + machines. The default is to not promote prototypes. + + -- Macro: PUSH_ARGS + A C expression. If nonzero, push insns will be used to pass + outgoing arguments. If the target machine does not have a push + instruction, set it to zero. That directs GCC to use an alternate + strategy: to allocate the entire argument block and then store the + arguments into it. When `PUSH_ARGS' is nonzero, `PUSH_ROUNDING' + must be defined too. + + -- Macro: PUSH_ARGS_REVERSED + A C expression. If nonzero, function arguments will be evaluated + from last to first, rather than from first to last. If this macro + is not defined, it defaults to `PUSH_ARGS' on targets where the + stack and args grow in opposite directions, and 0 otherwise. + + -- Macro: PUSH_ROUNDING (NPUSHED) + A C expression that is the number of bytes actually pushed onto the + stack when an instruction attempts to push NPUSHED bytes. + + On some machines, the definition + + #define PUSH_ROUNDING(BYTES) (BYTES) + + will suffice. But on other machines, instructions that appear to + push one byte actually push two bytes in an attempt to maintain + alignment. Then the definition should be + + #define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1) + + If the value of this macro has a type, it should be an unsigned + type. + + -- Macro: ACCUMULATE_OUTGOING_ARGS + A C expression. If nonzero, the maximum amount of space required + for outgoing arguments will be computed and placed into the + variable `current_function_outgoing_args_size'. No space will be + pushed onto the stack for each call; instead, the function + prologue should increase the stack frame size by this amount. + + Setting both `PUSH_ARGS' and `ACCUMULATE_OUTGOING_ARGS' is not + proper. + + -- Macro: REG_PARM_STACK_SPACE (FNDECL) + Define this macro if functions should assume that stack space has + been allocated for arguments even when their values are passed in + registers. + + The value of this macro is the size, in bytes, of the area + reserved for arguments passed in registers for the function + represented by FNDECL, which can be zero if GCC is calling a + library function. The argument FNDECL can be the FUNCTION_DECL, + or the type itself of the function. + + This space can be allocated by the caller, or be a part of the + machine-dependent stack frame: `OUTGOING_REG_PARM_STACK_SPACE' says + which. + + -- Macro: OUTGOING_REG_PARM_STACK_SPACE (FNTYPE) + Define this to a nonzero value if it is the responsibility of the + caller to allocate the area reserved for arguments passed in + registers when calling a function of FNTYPE. FNTYPE may be NULL + if the function called is a library function. + + If `ACCUMULATE_OUTGOING_ARGS' is defined, this macro controls + whether the space for these arguments counts in the value of + `current_function_outgoing_args_size'. + + -- Macro: STACK_PARMS_IN_REG_PARM_AREA + Define this macro if `REG_PARM_STACK_SPACE' is defined, but the + stack parameters don't skip the area specified by it. + + Normally, when a parameter is not passed in registers, it is + placed on the stack beyond the `REG_PARM_STACK_SPACE' area. + Defining this macro suppresses this behavior and causes the + parameter to be passed on the stack in its natural location. + + -- Target Hook: int TARGET_RETURN_POPS_ARGS (tree FUNDECL, tree + FUNTYPE, int SIZE) + This target hook returns the number of bytes of its own arguments + that a function pops on returning, or 0 if the function pops no + arguments and the caller must therefore pop them all after the + function returns. + + FUNDECL is a C variable whose value is a tree node that describes + the function in question. Normally it is a node of type + `FUNCTION_DECL' that describes the declaration of the function. + From this you can obtain the `DECL_ATTRIBUTES' of the function. + + FUNTYPE is a C variable whose value is a tree node that describes + the function in question. Normally it is a node of type + `FUNCTION_TYPE' that describes the data type of the function. + From this it is possible to obtain the data types of the value and + arguments (if known). + + When a call to a library function is being considered, FUNDECL + will contain an identifier node for the library function. Thus, if + you need to distinguish among various library functions, you can + do so by their names. Note that "library function" in this + context means a function used to perform arithmetic, whose name is + known specially in the compiler and was not mentioned in the C + code being compiled. + + SIZE is the number of bytes of arguments passed on the stack. If + a variable number of bytes is passed, it is zero, and argument + popping will always be the responsibility of the calling function. + + On the VAX, all functions always pop their arguments, so the + definition of this macro is SIZE. On the 68000, using the standard + calling convention, no functions pop their arguments, so the value + of the macro is always 0 in this case. But an alternative calling + convention is available in which functions that take a fixed + number of arguments pop them but other functions (such as + `printf') pop nothing (the caller pops all). When this convention + is in use, FUNTYPE is examined to determine whether a function + takes a fixed number of arguments. + + -- Macro: CALL_POPS_ARGS (CUM) + A C expression that should indicate the number of bytes a call + sequence pops off the stack. It is added to the value of + `RETURN_POPS_ARGS' when compiling a function call. + + CUM is the variable in which all arguments to the called function + have been accumulated. + + On certain architectures, such as the SH5, a call trampoline is + used that pops certain registers off the stack, depending on the + arguments that have been passed to the function. Since this is a + property of the call site, not of the called function, + `RETURN_POPS_ARGS' is not appropriate. + + +File: gccint.info, Node: Register Arguments, Next: Scalar Return, Prev: Stack Arguments, Up: Stack and Calling + +17.10.7 Passing Arguments in Registers +-------------------------------------- + +This section describes the macros which let you control how various +types of arguments are passed in registers or how they are arranged in +the stack. + + -- Macro: FUNCTION_ARG (CUM, MODE, TYPE, NAMED) + A C expression that controls whether a function argument is passed + in a register, and which register. + + The arguments are CUM, which summarizes all the previous + arguments; MODE, the machine mode of the argument; TYPE, the data + type of the argument as a tree node or 0 if that is not known + (which happens for C support library functions); and NAMED, which + is 1 for an ordinary argument and 0 for nameless arguments that + correspond to `...' in the called function's prototype. TYPE can + be an incomplete type if a syntax error has previously occurred. + + The value of the expression is usually either a `reg' RTX for the + hard register in which to pass the argument, or zero to pass the + argument on the stack. + + For machines like the VAX and 68000, where normally all arguments + are pushed, zero suffices as a definition. + + The value of the expression can also be a `parallel' RTX. This is + used when an argument is passed in multiple locations. The mode + of the `parallel' should be the mode of the entire argument. The + `parallel' holds any number of `expr_list' pairs; each one + describes where part of the argument is passed. In each + `expr_list' the first operand must be a `reg' RTX for the hard + register in which to pass this part of the argument, and the mode + of the register RTX indicates how large this part of the argument + is. The second operand of the `expr_list' is a `const_int' which + gives the offset in bytes into the entire argument of where this + part starts. As a special exception the first `expr_list' in the + `parallel' RTX may have a first operand of zero. This indicates + that the entire argument is also stored on the stack. + + The last time this macro is called, it is called with `MODE == + VOIDmode', and its result is passed to the `call' or `call_value' + pattern as operands 2 and 3 respectively. + + The usual way to make the ISO library `stdarg.h' work on a machine + where some arguments are usually passed in registers, is to cause + nameless arguments to be passed on the stack instead. This is done + by making `FUNCTION_ARG' return 0 whenever NAMED is 0. + + You may use the hook `targetm.calls.must_pass_in_stack' in the + definition of this macro to determine if this argument is of a + type that must be passed in the stack. If `REG_PARM_STACK_SPACE' + is not defined and `FUNCTION_ARG' returns nonzero for such an + argument, the compiler will abort. If `REG_PARM_STACK_SPACE' is + defined, the argument will be computed in the stack and then + loaded into a register. + + -- Target Hook: bool TARGET_MUST_PASS_IN_STACK (enum machine_mode + MODE, const_tree TYPE) + This target hook should return `true' if we should not pass TYPE + solely in registers. The file `expr.h' defines a definition that + is usually appropriate, refer to `expr.h' for additional + documentation. + + -- Macro: FUNCTION_INCOMING_ARG (CUM, MODE, TYPE, NAMED) + Define this macro if the target machine has "register windows", so + that the register in which a function sees an arguments is not + necessarily the same as the one in which the caller passed the + argument. + + For such machines, `FUNCTION_ARG' computes the register in which + the caller passes the value, and `FUNCTION_INCOMING_ARG' should be + defined in a similar fashion to tell the function being called + where the arguments will arrive. + + If `FUNCTION_INCOMING_ARG' is not defined, `FUNCTION_ARG' serves + both purposes. + + -- Target Hook: int TARGET_ARG_PARTIAL_BYTES (CUMULATIVE_ARGS *CUM, + enum machine_mode MODE, tree TYPE, bool NAMED) + This target hook returns the number of bytes at the beginning of an + argument that must be put in registers. The value must be zero for + arguments that are passed entirely in registers or that are + entirely pushed on the stack. + + On some machines, certain arguments must be passed partially in + registers and partially in memory. On these machines, typically + the first few words of arguments are passed in registers, and the + rest on the stack. If a multi-word argument (a `double' or a + structure) crosses that boundary, its first few words must be + passed in registers and the rest must be pushed. This macro tells + the compiler when this occurs, and how many bytes should go in + registers. + + `FUNCTION_ARG' for these arguments should return the first + register to be used by the caller for this argument; likewise + `FUNCTION_INCOMING_ARG', for the called function. + + -- Target Hook: bool TARGET_PASS_BY_REFERENCE (CUMULATIVE_ARGS *CUM, + enum machine_mode MODE, const_tree TYPE, bool NAMED) + This target hook should return `true' if an argument at the + position indicated by CUM should be passed by reference. This + predicate is queried after target independent reasons for being + passed by reference, such as `TREE_ADDRESSABLE (type)'. + + If the hook returns true, a copy of that argument is made in + memory and a pointer to the argument is passed instead of the + argument itself. The pointer is passed in whatever way is + appropriate for passing a pointer to that type. + + -- Target Hook: bool TARGET_CALLEE_COPIES (CUMULATIVE_ARGS *CUM, enum + machine_mode MODE, const_tree TYPE, bool NAMED) + The function argument described by the parameters to this hook is + known to be passed by reference. The hook should return true if + the function argument should be copied by the callee instead of + copied by the caller. + + For any argument for which the hook returns true, if it can be + determined that the argument is not modified, then a copy need not + be generated. + + The default version of this hook always returns false. + + -- Macro: CUMULATIVE_ARGS + A C type for declaring a variable that is used as the first + argument of `FUNCTION_ARG' and other related values. For some + target machines, the type `int' suffices and can hold the number + of bytes of argument so far. + + There is no need to record in `CUMULATIVE_ARGS' anything about the + arguments that have been passed on the stack. The compiler has + other variables to keep track of that. For target machines on + which all arguments are passed on the stack, there is no need to + store anything in `CUMULATIVE_ARGS'; however, the data structure + must exist and should not be empty, so use `int'. + + -- Macro: OVERRIDE_ABI_FORMAT (FNDECL) + If defined, this macro is called before generating any code for a + function, but after the CFUN descriptor for the function has been + created. The back end may use this macro to update CFUN to + reflect an ABI other than that which would normally be used by + default. If the compiler is generating code for a + compiler-generated function, FNDECL may be `NULL'. + + -- Macro: INIT_CUMULATIVE_ARGS (CUM, FNTYPE, LIBNAME, FNDECL, + N_NAMED_ARGS) + A C statement (sans semicolon) for initializing the variable CUM + for the state at the beginning of the argument list. The variable + has type `CUMULATIVE_ARGS'. The value of FNTYPE is the tree node + for the data type of the function which will receive the args, or + 0 if the args are to a compiler support library function. For + direct calls that are not libcalls, FNDECL contain the declaration + node of the function. FNDECL is also set when + `INIT_CUMULATIVE_ARGS' is used to find arguments for the function + being compiled. N_NAMED_ARGS is set to the number of named + arguments, including a structure return address if it is passed as + a parameter, when making a call. When processing incoming + arguments, N_NAMED_ARGS is set to -1. + + When processing a call to a compiler support library function, + LIBNAME identifies which one. It is a `symbol_ref' rtx which + contains the name of the function, as a string. LIBNAME is 0 when + an ordinary C function call is being processed. Thus, each time + this macro is called, either LIBNAME or FNTYPE is nonzero, but + never both of them at once. + + -- Macro: INIT_CUMULATIVE_LIBCALL_ARGS (CUM, MODE, LIBNAME) + Like `INIT_CUMULATIVE_ARGS' but only used for outgoing libcalls, + it gets a `MODE' argument instead of FNTYPE, that would be `NULL'. + INDIRECT would always be zero, too. If this macro is not defined, + `INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname, 0)' is used instead. + + -- Macro: INIT_CUMULATIVE_INCOMING_ARGS (CUM, FNTYPE, LIBNAME) + Like `INIT_CUMULATIVE_ARGS' but overrides it for the purposes of + finding the arguments for the function being compiled. If this + macro is undefined, `INIT_CUMULATIVE_ARGS' is used instead. + + The value passed for LIBNAME is always 0, since library routines + with special calling conventions are never compiled with GCC. The + argument LIBNAME exists for symmetry with `INIT_CUMULATIVE_ARGS'. + + -- Macro: FUNCTION_ARG_ADVANCE (CUM, MODE, TYPE, NAMED) + A C statement (sans semicolon) to update the summarizer variable + CUM to advance past an argument in the argument list. The values + MODE, TYPE and NAMED describe that argument. Once this is done, + the variable CUM is suitable for analyzing the _following_ + argument with `FUNCTION_ARG', etc. + + This macro need not do anything if the argument in question was + passed on the stack. The compiler knows how to track the amount + of stack space used for arguments without any special help. + + -- Macro: FUNCTION_ARG_OFFSET (MODE, TYPE) + If defined, a C expression that is the number of bytes to add to + the offset of the argument passed in memory. This is needed for + the SPU, which passes `char' and `short' arguments in the preferred + slot that is in the middle of the quad word instead of starting at + the top. + + -- Macro: FUNCTION_ARG_PADDING (MODE, TYPE) + If defined, a C expression which determines whether, and in which + direction, to pad out an argument with extra space. The value + should be of type `enum direction': either `upward' to pad above + the argument, `downward' to pad below, or `none' to inhibit + padding. + + The _amount_ of padding is always just enough to reach the next + multiple of `TARGET_FUNCTION_ARG_BOUNDARY'; this macro does not + control it. + + This macro has a default definition which is right for most + systems. For little-endian machines, the default is to pad + upward. For big-endian machines, the default is to pad downward + for an argument of constant size shorter than an `int', and upward + otherwise. + + -- Macro: PAD_VARARGS_DOWN + If defined, a C expression which determines whether the default + implementation of va_arg will attempt to pad down before reading + the next argument, if that argument is smaller than its aligned + space as controlled by `PARM_BOUNDARY'. If this macro is not + defined, all such arguments are padded down if `BYTES_BIG_ENDIAN' + is true. + + -- Macro: BLOCK_REG_PADDING (MODE, TYPE, FIRST) + Specify padding for the last element of a block move between + registers and memory. FIRST is nonzero if this is the only + element. Defining this macro allows better control of register + function parameters on big-endian machines, without using + `PARALLEL' rtl. In particular, `MUST_PASS_IN_STACK' need not test + padding and mode of types in registers, as there is no longer a + "wrong" part of a register; For example, a three byte aggregate + may be passed in the high part of a register if so required. + + -- Target Hook: unsigned int TARGET_FUNCTION_ARG_BOUNDARY (enum + machine_mode MODE, const_tree TYPE) + This hook returns the alignment boundary, in bits, of an argument + with the specified mode and type. The default hook returns + `PARM_BOUNDARY' for all arguments. + + -- Macro: FUNCTION_ARG_REGNO_P (REGNO) + A C expression that is nonzero if REGNO is the number of a hard + register in which function arguments are sometimes passed. This + does _not_ include implicit arguments such as the static chain and + the structure-value address. On many machines, no registers can be + used for this purpose since all function arguments are pushed on + the stack. + + -- Target Hook: bool TARGET_SPLIT_COMPLEX_ARG (const_tree TYPE) + This hook should return true if parameter of type TYPE are passed + as two scalar parameters. By default, GCC will attempt to pack + complex arguments into the target's word size. Some ABIs require + complex arguments to be split and treated as their individual + components. For example, on AIX64, complex floats should be + passed in a pair of floating point registers, even though a + complex float would fit in one 64-bit floating point register. + + The default value of this hook is `NULL', which is treated as + always false. + + -- Target Hook: tree TARGET_BUILD_BUILTIN_VA_LIST (void) + This hook returns a type node for `va_list' for the target. The + default version of the hook returns `void*'. + + -- Target Hook: int TARGET_ENUM_VA_LIST_P (int IDX, const char + **PNAME, tree *PTREE) + This target hook is used in function `c_common_nodes_and_builtins' + to iterate through the target specific builtin types for va_list. + The variable IDX is used as iterator. PNAME has to be a pointer to + a `const char *' and PTREE a pointer to a `tree' typed variable. + The arguments PNAME and PTREE are used to store the result of this + macro and are set to the name of the va_list builtin type and its + internal type. If the return value of this macro is zero, then + there is no more element. Otherwise the IDX should be increased + for the next call of this macro to iterate through all types. + + -- Target Hook: tree TARGET_FN_ABI_VA_LIST (tree FNDECL) + This hook returns the va_list type of the calling convention + specified by FNDECL. The default version of this hook returns + `va_list_type_node'. + + -- Target Hook: tree TARGET_CANONICAL_VA_LIST_TYPE (tree TYPE) + This hook returns the va_list type of the calling convention + specified by the type of TYPE. If TYPE is not a valid va_list + type, it returns `NULL_TREE'. + + -- Target Hook: tree TARGET_GIMPLIFY_VA_ARG_EXPR (tree VALIST, tree + TYPE, gimple_seq *PRE_P, gimple_seq *POST_P) + This hook performs target-specific gimplification of + `VA_ARG_EXPR'. The first two parameters correspond to the + arguments to `va_arg'; the latter two are as in + `gimplify.c:gimplify_expr'. + + -- Target Hook: bool TARGET_VALID_POINTER_MODE (enum machine_mode MODE) + Define this to return nonzero if the port can handle pointers with + machine mode MODE. The default version of this hook returns true + for both `ptr_mode' and `Pmode'. + + -- Target Hook: bool TARGET_REF_MAY_ALIAS_ERRNO (struct ao_ref_s *REF) + Define this to return nonzero if the memory reference REF may + alias with the system C library errno location. The default + version of this hook assumes the system C library errno location + is either a declaration of type int or accessed by dereferencing + a pointer to int. + + -- Target Hook: bool TARGET_SCALAR_MODE_SUPPORTED_P (enum machine_mode + MODE) + Define this to return nonzero if the port is prepared to handle + insns involving scalar mode MODE. For a scalar mode to be + considered supported, all the basic arithmetic and comparisons + must work. + + The default version of this hook returns true for any mode + required to handle the basic C types (as defined by the port). + Included here are the double-word arithmetic supported by the code + in `optabs.c'. + + -- Target Hook: bool TARGET_VECTOR_MODE_SUPPORTED_P (enum machine_mode + MODE) + Define this to return nonzero if the port is prepared to handle + insns involving vector mode MODE. At the very least, it must have + move patterns for this mode. + + -- Target Hook: bool TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P (enum + machine_mode MODE) + Define this to return nonzero for machine modes for which the port + has small register classes. If this target hook returns nonzero + for a given MODE, the compiler will try to minimize the lifetime + of registers in MODE. The hook may be called with `VOIDmode' as + argument. In this case, the hook is expected to return nonzero if + it returns nonzero for any mode. + + On some machines, it is risky to let hard registers live across + arbitrary insns. Typically, these machines have instructions that + require values to be in specific registers (like an accumulator), + and reload will fail if the required hard register is used for + another purpose across such an insn. + + Passes before reload do not know which hard registers will be used + in an instruction, but the machine modes of the registers set or + used in the instruction are already known. And for some machines, + register classes are small for, say, integer registers but not for + floating point registers. For example, the AMD x86-64 + architecture requires specific registers for the legacy x86 + integer instructions, but there are many SSE registers for + floating point operations. On such targets, a good strategy may + be to return nonzero from this hook for `INTEGRAL_MODE_P' machine + modes but zero for the SSE register classes. + + The default version of this hook returns false for any mode. It + is always safe to redefine this hook to return with a nonzero + value. But if you unnecessarily define it, you will reduce the + amount of optimizations that can be performed in some cases. If + you do not define this hook to return a nonzero value when it is + required, the compiler will run out of spill registers and print a + fatal error message. + + -- Target Hook: unsigned int TARGET_FLAGS_REGNUM + If the target has a dedicated flags register, and it needs to use + the post-reload comparison elimination pass, then this value + should be set appropriately. + + +File: gccint.info, Node: Scalar Return, Next: Aggregate Return, Prev: Register Arguments, Up: Stack and Calling + +17.10.8 How Scalar Function Values Are Returned +----------------------------------------------- + +This section discusses the macros that control returning scalars as +values--values that can fit in registers. + + -- Target Hook: rtx TARGET_FUNCTION_VALUE (const_tree RET_TYPE, + const_tree FN_DECL_OR_TYPE, bool OUTGOING) + Define this to return an RTX representing the place where a + function returns or receives a value of data type RET_TYPE, a tree + node representing a data type. FN_DECL_OR_TYPE is a tree node + representing `FUNCTION_DECL' or `FUNCTION_TYPE' of a function + being called. If OUTGOING is false, the hook should compute the + register in which the caller will see the return value. + Otherwise, the hook should return an RTX representing the place + where a function returns a value. + + On many machines, only `TYPE_MODE (RET_TYPE)' is relevant. + (Actually, on most machines, scalar values are returned in the same + place regardless of mode.) The value of the expression is usually + a `reg' RTX for the hard register where the return value is stored. + The value can also be a `parallel' RTX, if the return value is in + multiple places. See `FUNCTION_ARG' for an explanation of the + `parallel' form. Note that the callee will populate every + location specified in the `parallel', but if the first element of + the `parallel' contains the whole return value, callers will use + that element as the canonical location and ignore the others. The + m68k port uses this type of `parallel' to return pointers in both + `%a0' (the canonical location) and `%d0'. + + If `TARGET_PROMOTE_FUNCTION_RETURN' returns true, you must apply + the same promotion rules specified in `PROMOTE_MODE' if VALTYPE is + a scalar type. + + If the precise function being called is known, FUNC is a tree node + (`FUNCTION_DECL') for it; otherwise, FUNC is a null pointer. This + makes it possible to use a different value-returning convention + for specific functions when all their calls are known. + + Some target machines have "register windows" so that the register + in which a function returns its value is not the same as the one + in which the caller sees the value. For such machines, you should + return different RTX depending on OUTGOING. + + `TARGET_FUNCTION_VALUE' is not used for return values with + aggregate data types, because these are returned in another way. + See `TARGET_STRUCT_VALUE_RTX' and related macros, below. + + -- Macro: FUNCTION_VALUE (VALTYPE, FUNC) + This macro has been deprecated. Use `TARGET_FUNCTION_VALUE' for a + new target instead. + + -- Macro: LIBCALL_VALUE (MODE) + A C expression to create an RTX representing the place where a + library function returns a value of mode MODE. + + Note that "library function" in this context means a compiler + support routine, used to perform arithmetic, whose name is known + specially by the compiler and was not mentioned in the C code being + compiled. + + -- Target Hook: rtx TARGET_LIBCALL_VALUE (enum machine_mode MODE, + const_rtx FUN) + Define this hook if the back-end needs to know the name of the + libcall function in order to determine where the result should be + returned. + + The mode of the result is given by MODE and the name of the called + library function is given by FUN. The hook should return an RTX + representing the place where the library function result will be + returned. + + If this hook is not defined, then LIBCALL_VALUE will be used. + + -- Macro: FUNCTION_VALUE_REGNO_P (REGNO) + A C expression that is nonzero if REGNO is the number of a hard + register in which the values of called function may come back. + + A register whose use for returning values is limited to serving as + the second of a pair (for a value of type `double', say) need not + be recognized by this macro. So for most machines, this definition + suffices: + + #define FUNCTION_VALUE_REGNO_P(N) ((N) == 0) + + If the machine has register windows, so that the caller and the + called function use different registers for the return value, this + macro should recognize only the caller's register numbers. + + This macro has been deprecated. Use + `TARGET_FUNCTION_VALUE_REGNO_P' for a new target instead. + + -- Target Hook: bool TARGET_FUNCTION_VALUE_REGNO_P (const unsigned int + REGNO) + A target hook that return `true' if REGNO is the number of a hard + register in which the values of called function may come back. + + A register whose use for returning values is limited to serving as + the second of a pair (for a value of type `double', say) need not + be recognized by this target hook. + + If the machine has register windows, so that the caller and the + called function use different registers for the return value, this + target hook should recognize only the caller's register numbers. + + If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be + used. + + -- Macro: APPLY_RESULT_SIZE + Define this macro if `untyped_call' and `untyped_return' need more + space than is implied by `FUNCTION_VALUE_REGNO_P' for saving and + restoring an arbitrary return value. + + -- Target Hook: bool TARGET_RETURN_IN_MSB (const_tree TYPE) + This hook should return true if values of type TYPE are returned + at the most significant end of a register (in other words, if they + are padded at the least significant end). You can assume that TYPE + is returned in a register; the caller is required to check this. + + Note that the register provided by `TARGET_FUNCTION_VALUE' must be + able to hold the complete return value. For example, if a 1-, 2- + or 3-byte structure is returned at the most significant end of a + 4-byte register, `TARGET_FUNCTION_VALUE' should provide an + `SImode' rtx. + + +File: gccint.info, Node: Aggregate Return, Next: Caller Saves, Prev: Scalar Return, Up: Stack and Calling + +17.10.9 How Large Values Are Returned +------------------------------------- + +When a function value's mode is `BLKmode' (and in some other cases), +the value is not returned according to `TARGET_FUNCTION_VALUE' (*note +Scalar Return::). Instead, the caller passes the address of a block of +memory in which the value should be stored. This address is called the +"structure value address". + + This section describes how to control returning structure values in +memory. + + -- Target Hook: bool TARGET_RETURN_IN_MEMORY (const_tree TYPE, + const_tree FNTYPE) + This target hook should return a nonzero value to say to return the + function value in memory, just as large structures are always + returned. Here TYPE will be the data type of the value, and FNTYPE + will be the type of the function doing the returning, or `NULL' for + libcalls. + + Note that values of mode `BLKmode' must be explicitly handled by + this function. Also, the option `-fpcc-struct-return' takes + effect regardless of this macro. On most systems, it is possible + to leave the hook undefined; this causes a default definition to + be used, whose value is the constant 1 for `BLKmode' values, and 0 + otherwise. + + Do not use this hook to indicate that structures and unions should + always be returned in memory. You should instead use + `DEFAULT_PCC_STRUCT_RETURN' to indicate this. + + -- Macro: DEFAULT_PCC_STRUCT_RETURN + Define this macro to be 1 if all structure and union return values + must be in memory. Since this results in slower code, this should + be defined only if needed for compatibility with other compilers + or with an ABI. If you define this macro to be 0, then the + conventions used for structure and union return values are decided + by the `TARGET_RETURN_IN_MEMORY' target hook. + + If not defined, this defaults to the value 1. + + -- Target Hook: rtx TARGET_STRUCT_VALUE_RTX (tree FNDECL, int INCOMING) + This target hook should return the location of the structure value + address (normally a `mem' or `reg'), or 0 if the address is passed + as an "invisible" first argument. Note that FNDECL may be `NULL', + for libcalls. You do not need to define this target hook if the + address is always passed as an "invisible" first argument. + + On some architectures the place where the structure value address + is found by the called function is not the same place that the + caller put it. This can be due to register windows, or it could + be because the function prologue moves it to a different place. + INCOMING is `1' or `2' when the location is needed in the context + of the called function, and `0' in the context of the caller. + + If INCOMING is nonzero and the address is to be found on the + stack, return a `mem' which refers to the frame pointer. If + INCOMING is `2', the result is being used to fetch the structure + value address at the beginning of a function. If you need to emit + adjusting code, you should do it at this point. + + -- Macro: PCC_STATIC_STRUCT_RETURN + Define this macro if the usual system convention on the target + machine for returning structures and unions is for the called + function to return the address of a static variable containing the + value. + + Do not define this if the usual system convention is for the + caller to pass an address to the subroutine. + + This macro has effect in `-fpcc-struct-return' mode, but it does + nothing when you use `-freg-struct-return' mode. + + -- Target Hook: enum machine_mode TARGET_GET_RAW_RESULT_MODE (int + REGNO) + This target hook returns the mode to be used when accessing raw + return registers in `__builtin_return'. Define this macro if the + value in REG_RAW_MODE is not correct. + + -- Target Hook: enum machine_mode TARGET_GET_RAW_ARG_MODE (int REGNO) + This target hook returns the mode to be used when accessing raw + argument registers in `__builtin_apply_args'. Define this macro + if the value in REG_RAW_MODE is not correct. + + +File: gccint.info, Node: Caller Saves, Next: Function Entry, Prev: Aggregate Return, Up: Stack and Calling + +17.10.10 Caller-Saves Register Allocation +----------------------------------------- + +If you enable it, GCC can save registers around function calls. This +makes it possible to use call-clobbered registers to hold variables that +must live across calls. + + -- Macro: CALLER_SAVE_PROFITABLE (REFS, CALLS) + A C expression to determine whether it is worthwhile to consider + placing a pseudo-register in a call-clobbered hard register and + saving and restoring it around each function call. The expression + should be 1 when this is worth doing, and 0 otherwise. + + If you don't define this macro, a default is used which is good on + most machines: `4 * CALLS < REFS'. + + -- Macro: HARD_REGNO_CALLER_SAVE_MODE (REGNO, NREGS) + A C expression specifying which mode is required for saving NREGS + of a pseudo-register in call-clobbered hard register REGNO. If + REGNO is unsuitable for caller save, `VOIDmode' should be + returned. For most machines this macro need not be defined since + GCC will select the smallest suitable mode. + + +File: gccint.info, Node: Function Entry, Next: Profiling, Prev: Caller Saves, Up: Stack and Calling + +17.10.11 Function Entry and Exit +-------------------------------- + +This section describes the macros that output function entry +("prologue") and exit ("epilogue") code. + + -- Target Hook: void TARGET_ASM_FUNCTION_PROLOGUE (FILE *FILE, + HOST_WIDE_INT SIZE) + If defined, a function that outputs the assembler code for entry + to a function. The prologue is responsible for setting up the + stack frame, initializing the frame pointer register, saving + registers that must be saved, and allocating SIZE additional bytes + of storage for the local variables. SIZE is an integer. FILE is + a stdio stream to which the assembler code should be output. + + The label for the beginning of the function need not be output by + this macro. That has already been done when the macro is run. + + To determine which registers to save, the macro can refer to the + array `regs_ever_live': element R is nonzero if hard register R is + used anywhere within the function. This implies the function + prologue should save register R, provided it is not one of the + call-used registers. (`TARGET_ASM_FUNCTION_EPILOGUE' must + likewise use `regs_ever_live'.) + + On machines that have "register windows", the function entry code + does not save on the stack the registers that are in the windows, + even if they are supposed to be preserved by function calls; + instead it takes appropriate steps to "push" the register stack, + if any non-call-used registers are used in the function. + + On machines where functions may or may not have frame-pointers, the + function entry code must vary accordingly; it must set up the frame + pointer if one is wanted, and not otherwise. To determine whether + a frame pointer is in wanted, the macro can refer to the variable + `frame_pointer_needed'. The variable's value will be 1 at run + time in a function that needs a frame pointer. *Note + Elimination::. + + The function entry code is responsible for allocating any stack + space required for the function. This stack space consists of the + regions listed below. In most cases, these regions are allocated + in the order listed, with the last listed region closest to the + top of the stack (the lowest address if `STACK_GROWS_DOWNWARD' is + defined, and the highest address if it is not defined). You can + use a different order for a machine if doing so is more convenient + or required for compatibility reasons. Except in cases where + required by standard or by a debugger, there is no reason why the + stack layout used by GCC need agree with that used by other + compilers for a machine. + + -- Target Hook: void TARGET_ASM_FUNCTION_END_PROLOGUE (FILE *FILE) + If defined, a function that outputs assembler code at the end of a + prologue. This should be used when the function prologue is being + emitted as RTL, and you have some extra assembler that needs to be + emitted. *Note prologue instruction pattern::. + + -- Target Hook: void TARGET_ASM_FUNCTION_BEGIN_EPILOGUE (FILE *FILE) + If defined, a function that outputs assembler code at the start of + an epilogue. This should be used when the function epilogue is + being emitted as RTL, and you have some extra assembler that needs + to be emitted. *Note epilogue instruction pattern::. + + -- Target Hook: void TARGET_ASM_FUNCTION_EPILOGUE (FILE *FILE, + HOST_WIDE_INT SIZE) + If defined, a function that outputs the assembler code for exit + from a function. The epilogue is responsible for restoring the + saved registers and stack pointer to their values when the + function was called, and returning control to the caller. This + macro takes the same arguments as the macro + `TARGET_ASM_FUNCTION_PROLOGUE', and the registers to restore are + determined from `regs_ever_live' and `CALL_USED_REGISTERS' in the + same way. + + On some machines, there is a single instruction that does all the + work of returning from the function. On these machines, give that + instruction the name `return' and do not define the macro + `TARGET_ASM_FUNCTION_EPILOGUE' at all. + + Do not define a pattern named `return' if you want the + `TARGET_ASM_FUNCTION_EPILOGUE' to be used. If you want the target + switches to control whether return instructions or epilogues are + used, define a `return' pattern with a validity condition that + tests the target switches appropriately. If the `return' + pattern's validity condition is false, epilogues will be used. + + On machines where functions may or may not have frame-pointers, the + function exit code must vary accordingly. Sometimes the code for + these two cases is completely different. To determine whether a + frame pointer is wanted, the macro can refer to the variable + `frame_pointer_needed'. The variable's value will be 1 when + compiling a function that needs a frame pointer. + + Normally, `TARGET_ASM_FUNCTION_PROLOGUE' and + `TARGET_ASM_FUNCTION_EPILOGUE' must treat leaf functions specially. + The C variable `current_function_is_leaf' is nonzero for such a + function. *Note Leaf Functions::. + + On some machines, some functions pop their arguments on exit while + others leave that for the caller to do. For example, the 68020 + when given `-mrtd' pops arguments in functions that take a fixed + number of arguments. + + Your definition of the macro `RETURN_POPS_ARGS' decides which + functions pop their own arguments. `TARGET_ASM_FUNCTION_EPILOGUE' + needs to know what was decided. The number of bytes of the current + function's arguments that this function should pop is available in + `crtl->args.pops_args'. *Note Scalar Return::. + + * A region of `current_function_pretend_args_size' bytes of + uninitialized space just underneath the first argument arriving on + the stack. (This may not be at the very start of the allocated + stack region if the calling sequence has pushed anything else + since pushing the stack arguments. But usually, on such machines, + nothing else has been pushed yet, because the function prologue + itself does all the pushing.) This region is used on machines + where an argument may be passed partly in registers and partly in + memory, and, in some cases to support the features in `<stdarg.h>'. + + * An area of memory used to save certain registers used by the + function. The size of this area, which may also include space for + such things as the return address and pointers to previous stack + frames, is machine-specific and usually depends on which registers + have been used in the function. Machines with register windows + often do not require a save area. + + * A region of at least SIZE bytes, possibly rounded up to an + allocation boundary, to contain the local variables of the + function. On some machines, this region and the save area may + occur in the opposite order, with the save area closer to the top + of the stack. + + * Optionally, when `ACCUMULATE_OUTGOING_ARGS' is defined, a region of + `current_function_outgoing_args_size' bytes to be used for outgoing + argument lists of the function. *Note Stack Arguments::. + + -- Macro: EXIT_IGNORE_STACK + Define this macro as a C expression that is nonzero if the return + instruction or the function epilogue ignores the value of the stack + pointer; in other words, if it is safe to delete an instruction to + adjust the stack pointer before a return from the function. The + default is 0. + + Note that this macro's value is relevant only for functions for + which frame pointers are maintained. It is never safe to delete a + final stack adjustment in a function that has no frame pointer, + and the compiler knows this regardless of `EXIT_IGNORE_STACK'. + + -- Macro: EPILOGUE_USES (REGNO) + Define this macro as a C expression that is nonzero for registers + that are used by the epilogue or the `return' pattern. The stack + and frame pointer registers are already assumed to be used as + needed. + + -- Macro: EH_USES (REGNO) + Define this macro as a C expression that is nonzero for registers + that are used by the exception handling mechanism, and so should + be considered live on entry to an exception edge. + + -- Macro: DELAY_SLOTS_FOR_EPILOGUE + Define this macro if the function epilogue contains delay slots to + which instructions from the rest of the function can be "moved". + The definition should be a C expression whose value is an integer + representing the number of delay slots there. + + -- Macro: ELIGIBLE_FOR_EPILOGUE_DELAY (INSN, N) + A C expression that returns 1 if INSN can be placed in delay slot + number N of the epilogue. + + The argument N is an integer which identifies the delay slot now + being considered (since different slots may have different rules of + eligibility). It is never negative and is always less than the + number of epilogue delay slots (what `DELAY_SLOTS_FOR_EPILOGUE' + returns). If you reject a particular insn for a given delay slot, + in principle, it may be reconsidered for a subsequent delay slot. + Also, other insns may (at least in principle) be considered for + the so far unfilled delay slot. + + The insns accepted to fill the epilogue delay slots are put in an + RTL list made with `insn_list' objects, stored in the variable + `current_function_epilogue_delay_list'. The insn for the first + delay slot comes first in the list. Your definition of the macro + `TARGET_ASM_FUNCTION_EPILOGUE' should fill the delay slots by + outputting the insns in this list, usually by calling + `final_scan_insn'. + + You need not define this macro if you did not define + `DELAY_SLOTS_FOR_EPILOGUE'. + + -- Target Hook: void TARGET_ASM_OUTPUT_MI_THUNK (FILE *FILE, tree + THUNK_FNDECL, HOST_WIDE_INT DELTA, HOST_WIDE_INT + VCALL_OFFSET, tree FUNCTION) + A function that outputs the assembler code for a thunk function, + used to implement C++ virtual function calls with multiple + inheritance. The thunk acts as a wrapper around a virtual + function, adjusting the implicit object parameter before handing + control off to the real function. + + First, emit code to add the integer DELTA to the location that + contains the incoming first argument. Assume that this argument + contains a pointer, and is the one used to pass the `this' pointer + in C++. This is the incoming argument _before_ the function + prologue, e.g. `%o0' on a sparc. The addition must preserve the + values of all other incoming arguments. + + Then, if VCALL_OFFSET is nonzero, an additional adjustment should + be made after adding `delta'. In particular, if P is the adjusted + pointer, the following adjustment should be made: + + p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)] + + After the additions, emit code to jump to FUNCTION, which is a + `FUNCTION_DECL'. This is a direct pure jump, not a call, and does + not touch the return address. Hence returning from FUNCTION will + return to whoever called the current `thunk'. + + The effect must be as if FUNCTION had been called directly with + the adjusted first argument. This macro is responsible for + emitting all of the code for a thunk function; + `TARGET_ASM_FUNCTION_PROLOGUE' and `TARGET_ASM_FUNCTION_EPILOGUE' + are not invoked. + + The THUNK_FNDECL is redundant. (DELTA and FUNCTION have already + been extracted from it.) It might possibly be useful on some + targets, but probably not. + + If you do not define this macro, the target-independent code in + the C++ front end will generate a less efficient heavyweight thunk + that calls FUNCTION instead of jumping to it. The generic + approach does not support varargs. + + -- Target Hook: bool TARGET_ASM_CAN_OUTPUT_MI_THUNK (const_tree + THUNK_FNDECL, HOST_WIDE_INT DELTA, HOST_WIDE_INT + VCALL_OFFSET, const_tree FUNCTION) + A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would + be able to output the assembler code for the thunk function + specified by the arguments it is passed, and false otherwise. In + the latter case, the generic approach will be used by the C++ + front end, with the limitations previously exposed. + + +File: gccint.info, Node: Profiling, Next: Tail Calls, Prev: Function Entry, Up: Stack and Calling + +17.10.12 Generating Code for Profiling +-------------------------------------- + +These macros will help you generate code for profiling. + + -- Macro: FUNCTION_PROFILER (FILE, LABELNO) + A C statement or compound statement to output to FILE some + assembler code to call the profiling subroutine `mcount'. + + The details of how `mcount' expects to be called are determined by + your operating system environment, not by GCC. To figure them out, + compile a small program for profiling using the system's installed + C compiler and look at the assembler code that results. + + Older implementations of `mcount' expect the address of a counter + variable to be loaded into some register. The name of this + variable is `LP' followed by the number LABELNO, so you would + generate the name using `LP%d' in a `fprintf'. + + -- Macro: PROFILE_HOOK + A C statement or compound statement to output to FILE some assembly + code to call the profiling subroutine `mcount' even the target does + not support profiling. + + -- Macro: NO_PROFILE_COUNTERS + Define this macro to be an expression with a nonzero value if the + `mcount' subroutine on your system does not need a counter variable + allocated for each function. This is true for almost all modern + implementations. If you define this macro, you must not use the + LABELNO argument to `FUNCTION_PROFILER'. + + -- Macro: PROFILE_BEFORE_PROLOGUE + Define this macro if the code for function profiling should come + before the function prologue. Normally, the profiling code comes + after. + + +File: gccint.info, Node: Tail Calls, Next: Stack Smashing Protection, Prev: Profiling, Up: Stack and Calling + +17.10.13 Permitting tail calls +------------------------------ + + -- Target Hook: bool TARGET_FUNCTION_OK_FOR_SIBCALL (tree DECL, tree + EXP) + True if it is ok to do sibling call optimization for the specified + call expression EXP. DECL will be the called function, or `NULL' + if this is an indirect call. + + It is not uncommon for limitations of calling conventions to + prevent tail calls to functions outside the current unit of + translation, or during PIC compilation. The hook is used to + enforce these restrictions, as the `sibcall' md pattern can not + fail, or fall over to a "normal" call. The criteria for + successful sibling call optimization may vary greatly between + different architectures. + + -- Target Hook: void TARGET_EXTRA_LIVE_ON_ENTRY (bitmap REGS) + Add any hard registers to REGS that are live on entry to the + function. This hook only needs to be defined to provide registers + that cannot be found by examination of FUNCTION_ARG_REGNO_P, the + callee saved registers, STATIC_CHAIN_INCOMING_REGNUM, + STATIC_CHAIN_REGNUM, TARGET_STRUCT_VALUE_RTX, + FRAME_POINTER_REGNUM, EH_USES, FRAME_POINTER_REGNUM, + ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM. + + +File: gccint.info, Node: Stack Smashing Protection, Prev: Tail Calls, Up: Stack and Calling + +17.10.14 Stack smashing protection +---------------------------------- + + -- Target Hook: tree TARGET_STACK_PROTECT_GUARD (void) + This hook returns a `DECL' node for the external variable to use + for the stack protection guard. This variable is initialized by + the runtime to some random value and is used to initialize the + guard value that is placed at the top of the local stack frame. + The type of this variable must be `ptr_type_node'. + + The default version of this hook creates a variable called + `__stack_chk_guard', which is normally defined in `libgcc2.c'. + + -- Target Hook: tree TARGET_STACK_PROTECT_FAIL (void) + This hook returns a tree expression that alerts the runtime that + the stack protect guard variable has been modified. This + expression should involve a call to a `noreturn' function. + + The default version of this hook invokes a function called + `__stack_chk_fail', taking no arguments. This function is + normally defined in `libgcc2.c'. + + -- Target Hook: bool TARGET_SUPPORTS_SPLIT_STACK (bool REPORT, struct + gcc_options *OPTS) + Whether this target supports splitting the stack when the options + described in OPTS have been passed. This is called after options + have been parsed, so the target may reject splitting the stack in + some configurations. The default version of this hook returns + false. If REPORT is true, this function may issue a warning or + error; if REPORT is false, it must simply return a value + + +File: gccint.info, Node: Varargs, Next: Trampolines, Prev: Stack and Calling, Up: Target Macros + +17.11 Implementing the Varargs Macros +===================================== + +GCC comes with an implementation of `<varargs.h>' and `<stdarg.h>' that +work without change on machines that pass arguments on the stack. +Other machines require their own implementations of varargs, and the +two machine independent header files must have conditionals to include +it. + + ISO `<stdarg.h>' differs from traditional `<varargs.h>' mainly in the +calling convention for `va_start'. The traditional implementation +takes just one argument, which is the variable in which to store the +argument pointer. The ISO implementation of `va_start' takes an +additional second argument. The user is supposed to write the last +named argument of the function here. + + However, `va_start' should not use this argument. The way to find the +end of the named arguments is with the built-in functions described +below. + + -- Macro: __builtin_saveregs () + Use this built-in function to save the argument registers in + memory so that the varargs mechanism can access them. Both ISO + and traditional versions of `va_start' must use + `__builtin_saveregs', unless you use + `TARGET_SETUP_INCOMING_VARARGS' (see below) instead. + + On some machines, `__builtin_saveregs' is open-coded under the + control of the target hook `TARGET_EXPAND_BUILTIN_SAVEREGS'. On + other machines, it calls a routine written in assembler language, + found in `libgcc2.c'. + + Code generated for the call to `__builtin_saveregs' appears at the + beginning of the function, as opposed to where the call to + `__builtin_saveregs' is written, regardless of what the code is. + This is because the registers must be saved before the function + starts to use them for its own purposes. + + -- Macro: __builtin_next_arg (LASTARG) + This builtin returns the address of the first anonymous stack + argument, as type `void *'. If `ARGS_GROW_DOWNWARD', it returns + the address of the location above the first anonymous stack + argument. Use it in `va_start' to initialize the pointer for + fetching arguments from the stack. Also use it in `va_start' to + verify that the second parameter LASTARG is the last named argument + of the current function. + + -- Macro: __builtin_classify_type (OBJECT) + Since each machine has its own conventions for which data types are + passed in which kind of register, your implementation of `va_arg' + has to embody these conventions. The easiest way to categorize the + specified data type is to use `__builtin_classify_type' together + with `sizeof' and `__alignof__'. + + `__builtin_classify_type' ignores the value of OBJECT, considering + only its data type. It returns an integer describing what kind of + type that is--integer, floating, pointer, structure, and so on. + + The file `typeclass.h' defines an enumeration that you can use to + interpret the values of `__builtin_classify_type'. + + These machine description macros help implement varargs: + + -- Target Hook: rtx TARGET_EXPAND_BUILTIN_SAVEREGS (void) + If defined, this hook produces the machine-specific code for a + call to `__builtin_saveregs'. This code will be moved to the very + beginning of the function, before any parameter access are made. + The return value of this function should be an RTX that contains + the value to use as the return of `__builtin_saveregs'. + + -- Target Hook: void TARGET_SETUP_INCOMING_VARARGS (CUMULATIVE_ARGS + *ARGS_SO_FAR, enum machine_mode MODE, tree TYPE, int + *PRETEND_ARGS_SIZE, int SECOND_TIME) + This target hook offers an alternative to using + `__builtin_saveregs' and defining the hook + `TARGET_EXPAND_BUILTIN_SAVEREGS'. Use it to store the anonymous + register arguments into the stack so that all the arguments appear + to have been passed consecutively on the stack. Once this is + done, you can use the standard implementation of varargs that + works for machines that pass all their arguments on the stack. + + The argument ARGS_SO_FAR points to the `CUMULATIVE_ARGS' data + structure, containing the values that are obtained after + processing the named arguments. The arguments MODE and TYPE + describe the last named argument--its machine mode and its data + type as a tree node. + + The target hook should do two things: first, push onto the stack + all the argument registers _not_ used for the named arguments, and + second, store the size of the data thus pushed into the + `int'-valued variable pointed to by PRETEND_ARGS_SIZE. The value + that you store here will serve as additional offset for setting up + the stack frame. + + Because you must generate code to push the anonymous arguments at + compile time without knowing their data types, + `TARGET_SETUP_INCOMING_VARARGS' is only useful on machines that + have just a single category of argument register and use it + uniformly for all data types. + + If the argument SECOND_TIME is nonzero, it means that the + arguments of the function are being analyzed for the second time. + This happens for an inline function, which is not actually + compiled until the end of the source file. The hook + `TARGET_SETUP_INCOMING_VARARGS' should not generate any + instructions in this case. + + -- Target Hook: bool TARGET_STRICT_ARGUMENT_NAMING (CUMULATIVE_ARGS + *CA) + Define this hook to return `true' if the location where a function + argument is passed depends on whether or not it is a named + argument. + + This hook controls how the NAMED argument to `FUNCTION_ARG' is set + for varargs and stdarg functions. If this hook returns `true', + the NAMED argument is always true for named arguments, and false + for unnamed arguments. If it returns `false', but + `TARGET_PRETEND_OUTGOING_VARARGS_NAMED' returns `true', then all + arguments are treated as named. Otherwise, all named arguments + except the last are treated as named. + + You need not define this hook if it always returns `false'. + + -- Target Hook: bool TARGET_PRETEND_OUTGOING_VARARGS_NAMED + (CUMULATIVE_ARGS *CA) + If you need to conditionally change ABIs so that one works with + `TARGET_SETUP_INCOMING_VARARGS', but the other works like neither + `TARGET_SETUP_INCOMING_VARARGS' nor + `TARGET_STRICT_ARGUMENT_NAMING' was defined, then define this hook + to return `true' if `TARGET_SETUP_INCOMING_VARARGS' is used, + `false' otherwise. Otherwise, you should not define this hook. + + +File: gccint.info, Node: Trampolines, Next: Library Calls, Prev: Varargs, Up: Target Macros + +17.12 Trampolines for Nested Functions +====================================== + +A "trampoline" is a small piece of code that is created at run time +when the address of a nested function is taken. It normally resides on +the stack, in the stack frame of the containing function. These macros +tell GCC how to generate code to allocate and initialize a trampoline. + + The instructions in the trampoline must do two things: load a constant +address into the static chain register, and jump to the real address of +the nested function. On CISC machines such as the m68k, this requires +two instructions, a move immediate and a jump. Then the two addresses +exist in the trampoline as word-long immediate operands. On RISC +machines, it is often necessary to load each address into a register in +two parts. Then pieces of each address form separate immediate +operands. + + The code generated to initialize the trampoline must store the variable +parts--the static chain value and the function address--into the +immediate operands of the instructions. On a CISC machine, this is +simply a matter of copying each address to a memory reference at the +proper offset from the start of the trampoline. On a RISC machine, it +may be necessary to take out pieces of the address and store them +separately. + + -- Target Hook: void TARGET_ASM_TRAMPOLINE_TEMPLATE (FILE *F) + This hook is called by `assemble_trampoline_template' to output, + on the stream F, assembler code for a block of data that contains + the constant parts of a trampoline. This code should not include a + label--the label is taken care of automatically. + + If you do not define this hook, it means no template is needed for + the target. Do not define this hook on systems where the block + move code to copy the trampoline into place would be larger than + the code to generate it on the spot. + + -- Macro: TRAMPOLINE_SECTION + Return the section into which the trampoline template is to be + placed (*note Sections::). The default value is + `readonly_data_section'. + + -- Macro: TRAMPOLINE_SIZE + A C expression for the size in bytes of the trampoline, as an + integer. + + -- Macro: TRAMPOLINE_ALIGNMENT + Alignment required for trampolines, in bits. + + If you don't define this macro, the value of `FUNCTION_ALIGNMENT' + is used for aligning trampolines. + + -- Target Hook: void TARGET_TRAMPOLINE_INIT (rtx M_TRAMP, tree FNDECL, + rtx STATIC_CHAIN) + This hook is called to initialize a trampoline. M_TRAMP is an RTX + for the memory block for the trampoline; FNDECL is the + `FUNCTION_DECL' for the nested function; STATIC_CHAIN is an RTX + for the static chain value that should be passed to the function + when it is called. + + If the target defines `TARGET_ASM_TRAMPOLINE_TEMPLATE', then the + first thing this hook should do is emit a block move into M_TRAMP + from the memory block returned by `assemble_trampoline_template'. + Note that the block move need only cover the constant parts of the + trampoline. If the target isolates the variable parts of the + trampoline to the end, not all `TRAMPOLINE_SIZE' bytes need be + copied. + + If the target requires any other actions, such as flushing caches + or enabling stack execution, these actions should be performed + after initializing the trampoline proper. + + -- Target Hook: rtx TARGET_TRAMPOLINE_ADJUST_ADDRESS (rtx ADDR) + This hook should perform any machine-specific adjustment in the + address of the trampoline. Its argument contains the address of + the memory block that was passed to `TARGET_TRAMPOLINE_INIT'. In + case the address to be used for a function call should be + different from the address at which the template was stored, the + different address should be returned; otherwise ADDR should be + returned unchanged. If this hook is not defined, ADDR will be + used for function calls. + + Implementing trampolines is difficult on many machines because they +have separate instruction and data caches. Writing into a stack +location fails to clear the memory in the instruction cache, so when +the program jumps to that location, it executes the old contents. + + Here are two possible solutions. One is to clear the relevant parts of +the instruction cache whenever a trampoline is set up. The other is to +make all trampolines identical, by having them jump to a standard +subroutine. The former technique makes trampoline execution faster; the +latter makes initialization faster. + + To clear the instruction cache when a trampoline is initialized, define +the following macro. + + -- Macro: CLEAR_INSN_CACHE (BEG, END) + If defined, expands to a C expression clearing the _instruction + cache_ in the specified interval. The definition of this macro + would typically be a series of `asm' statements. Both BEG and END + are both pointer expressions. + + The operating system may also require the stack to be made executable +before calling the trampoline. To implement this requirement, define +the following macro. + + -- Macro: ENABLE_EXECUTE_STACK + Define this macro if certain operations must be performed before + executing code located on the stack. The macro should expand to a + series of C file-scope constructs (e.g. functions) and provide a + unique entry point named `__enable_execute_stack'. The target is + responsible for emitting calls to the entry point in the code, for + example from the `TARGET_TRAMPOLINE_INIT' hook. + + To use a standard subroutine, define the following macro. In addition, +you must make sure that the instructions in a trampoline fill an entire +cache line with identical instructions, or else ensure that the +beginning of the trampoline code is always aligned at the same point in +its cache line. Look in `m68k.h' as a guide. + + -- Macro: TRANSFER_FROM_TRAMPOLINE + Define this macro if trampolines need a special subroutine to do + their work. The macro should expand to a series of `asm' + statements which will be compiled with GCC. They go in a library + function named `__transfer_from_trampoline'. + + If you need to avoid executing the ordinary prologue code of a + compiled C function when you jump to the subroutine, you can do so + by placing a special label of your own in the assembler code. Use + one `asm' statement to generate an assembler label, and another to + make the label global. Then trampolines can use that label to + jump directly to your special assembler code. + + +File: gccint.info, Node: Library Calls, Next: Addressing Modes, Prev: Trampolines, Up: Target Macros + +17.13 Implicit Calls to Library Routines +======================================== + +Here is an explanation of implicit calls to library routines. + + -- Macro: DECLARE_LIBRARY_RENAMES + This macro, if defined, should expand to a piece of C code that + will get expanded when compiling functions for libgcc.a. It can + be used to provide alternate names for GCC's internal library + functions if there are ABI-mandated names that the compiler should + provide. + + -- Target Hook: void TARGET_INIT_LIBFUNCS (void) + This hook should declare additional library routines or rename + existing ones, using the functions `set_optab_libfunc' and + `init_one_libfunc' defined in `optabs.c'. `init_optabs' calls + this macro after initializing all the normal library routines. + + The default is to do nothing. Most ports don't need to define + this hook. + + -- Macro: FLOAT_LIB_COMPARE_RETURNS_BOOL (MODE, COMPARISON) + This macro should return `true' if the library routine that + implements the floating point comparison operator COMPARISON in + mode MODE will return a boolean, and FALSE if it will return a + tristate. + + GCC's own floating point libraries return tristates from the + comparison operators, so the default returns false always. Most + ports don't need to define this macro. + + -- Macro: TARGET_LIB_INT_CMP_BIASED + This macro should evaluate to `true' if the integer comparison + functions (like `__cmpdi2') return 0 to indicate that the first + operand is smaller than the second, 1 to indicate that they are + equal, and 2 to indicate that the first operand is greater than + the second. If this macro evaluates to `false' the comparison + functions return -1, 0, and 1 instead of 0, 1, and 2. If the + target uses the routines in `libgcc.a', you do not need to define + this macro. + + -- Macro: TARGET_EDOM + The value of `EDOM' on the target machine, as a C integer constant + expression. If you don't define this macro, GCC does not attempt + to deposit the value of `EDOM' into `errno' directly. Look in + `/usr/include/errno.h' to find the value of `EDOM' on your system. + + If you do not define `TARGET_EDOM', then compiled code reports + domain errors by calling the library function and letting it + report the error. If mathematical functions on your system use + `matherr' when there is an error, then you should leave + `TARGET_EDOM' undefined so that `matherr' is used normally. + + -- Macro: GEN_ERRNO_RTX + Define this macro as a C expression to create an rtl expression + that refers to the global "variable" `errno'. (On certain systems, + `errno' may not actually be a variable.) If you don't define this + macro, a reasonable default is used. + + -- Macro: TARGET_C99_FUNCTIONS + When this macro is nonzero, GCC will implicitly optimize `sin' + calls into `sinf' and similarly for other functions defined by C99 + standard. The default is zero because a number of existing + systems lack support for these functions in their runtime so this + macro needs to be redefined to one on systems that do support the + C99 runtime. + + -- Macro: TARGET_HAS_SINCOS + When this macro is nonzero, GCC will implicitly optimize calls to + `sin' and `cos' with the same argument to a call to `sincos'. The + default is zero. The target has to provide the following + functions: + void sincos(double x, double *sin, double *cos); + void sincosf(float x, float *sin, float *cos); + void sincosl(long double x, long double *sin, long double *cos); + + -- Macro: NEXT_OBJC_RUNTIME + Define this macro to generate code for Objective-C message sending + using the calling convention of the NeXT system. This calling + convention involves passing the object, the selector and the + method arguments all at once to the method-lookup library function. + + The default calling convention passes just the object and the + selector to the lookup function, which returns a pointer to the + method. + + +File: gccint.info, Node: Addressing Modes, Next: Anchored Addresses, Prev: Library Calls, Up: Target Macros + +17.14 Addressing Modes +====================== + +This is about addressing modes. + + -- Macro: HAVE_PRE_INCREMENT + -- Macro: HAVE_PRE_DECREMENT + -- Macro: HAVE_POST_INCREMENT + -- Macro: HAVE_POST_DECREMENT + A C expression that is nonzero if the machine supports + pre-increment, pre-decrement, post-increment, or post-decrement + addressing respectively. + + -- Macro: HAVE_PRE_MODIFY_DISP + -- Macro: HAVE_POST_MODIFY_DISP + A C expression that is nonzero if the machine supports pre- or + post-address side-effect generation involving constants other than + the size of the memory operand. + + -- Macro: HAVE_PRE_MODIFY_REG + -- Macro: HAVE_POST_MODIFY_REG + A C expression that is nonzero if the machine supports pre- or + post-address side-effect generation involving a register + displacement. + + -- Macro: CONSTANT_ADDRESS_P (X) + A C expression that is 1 if the RTX X is a constant which is a + valid address. On most machines the default definition of + `(CONSTANT_P (X) && GET_CODE (X) != CONST_DOUBLE)' is acceptable, + but a few machines are more restrictive as to which constant + addresses are supported. + + -- Macro: CONSTANT_P (X) + `CONSTANT_P', which is defined by target-independent code, accepts + integer-values expressions whose values are not explicitly known, + such as `symbol_ref', `label_ref', and `high' expressions and + `const' arithmetic expressions, in addition to `const_int' and + `const_double' expressions. + + -- Macro: MAX_REGS_PER_ADDRESS + A number, the maximum number of registers that can appear in a + valid memory address. Note that it is up to you to specify a + value equal to the maximum number that + `TARGET_LEGITIMATE_ADDRESS_P' would ever accept. + + -- Target Hook: bool TARGET_LEGITIMATE_ADDRESS_P (enum machine_mode + MODE, rtx X, bool STRICT) + A function that returns whether X (an RTX) is a legitimate memory + address on the target machine for a memory operand of mode MODE. + + Legitimate addresses are defined in two variants: a strict variant + and a non-strict one. The STRICT parameter chooses which variant + is desired by the caller. + + The strict variant is used in the reload pass. It must be defined + so that any pseudo-register that has not been allocated a hard + register is considered a memory reference. This is because in + contexts where some kind of register is required, a + pseudo-register with no hard register must be rejected. For + non-hard registers, the strict variant should look up the + `reg_renumber' array; it should then proceed using the hard + register number in the array, or treat the pseudo as a memory + reference if the array holds `-1'. + + The non-strict variant is used in other passes. It must be + defined to accept all pseudo-registers in every context where some + kind of register is required. + + Normally, constant addresses which are the sum of a `symbol_ref' + and an integer are stored inside a `const' RTX to mark them as + constant. Therefore, there is no need to recognize such sums + specifically as legitimate addresses. Normally you would simply + recognize any `const' as legitimate. + + Usually `PRINT_OPERAND_ADDRESS' is not prepared to handle constant + sums that are not marked with `const'. It assumes that a naked + `plus' indicates indexing. If so, then you _must_ reject such + naked constant sums as illegitimate addresses, so that none of + them will be given to `PRINT_OPERAND_ADDRESS'. + + On some machines, whether a symbolic address is legitimate depends + on the section that the address refers to. On these machines, + define the target hook `TARGET_ENCODE_SECTION_INFO' to store the + information into the `symbol_ref', and then check for it here. + When you see a `const', you will have to look inside it to find the + `symbol_ref' in order to determine the section. *Note Assembler + Format::. + + Some ports are still using a deprecated legacy substitute for this + hook, the `GO_IF_LEGITIMATE_ADDRESS' macro. This macro has this + syntax: + + #define GO_IF_LEGITIMATE_ADDRESS (MODE, X, LABEL) + + and should `goto LABEL' if the address X is a valid address on the + target machine for a memory operand of mode MODE. + + Compiler source files that want to use the strict variant of this + macro define the macro `REG_OK_STRICT'. You should use an `#ifdef + REG_OK_STRICT' conditional to define the strict variant in that + case and the non-strict variant otherwise. + + Using the hook is usually simpler because it limits the number of + files that are recompiled when changes are made. + + -- Macro: TARGET_MEM_CONSTRAINT + A single character to be used instead of the default `'m'' + character for general memory addresses. This defines the + constraint letter which matches the memory addresses accepted by + `TARGET_LEGITIMATE_ADDRESS_P'. Define this macro if you want to + support new address formats in your back end without changing the + semantics of the `'m'' constraint. This is necessary in order to + preserve functionality of inline assembly constructs using the + `'m'' constraint. + + -- Macro: FIND_BASE_TERM (X) + A C expression to determine the base term of address X, or to + provide a simplified version of X from which `alias.c' can easily + find the base term. This macro is used in only two places: + `find_base_value' and `find_base_term' in `alias.c'. + + It is always safe for this macro to not be defined. It exists so + that alias analysis can understand machine-dependent addresses. + + The typical use of this macro is to handle addresses containing a + label_ref or symbol_ref within an UNSPEC. + + -- Target Hook: rtx TARGET_LEGITIMIZE_ADDRESS (rtx X, rtx OLDX, enum + machine_mode MODE) + This hook is given an invalid memory address X for an operand of + mode MODE and should try to return a valid memory address. + + X will always be the result of a call to `break_out_memory_refs', + and OLDX will be the operand that was given to that function to + produce X. + + The code of the hook should not alter the substructure of X. If + it transforms X into a more legitimate form, it should return the + new X. + + It is not necessary for this hook to come up with a legitimate + address. The compiler has standard ways of doing so in all cases. + In fact, it is safe to omit this hook or make it return X if it + cannot find a valid way to legitimize the address. But often a + machine-dependent strategy can generate better code. + + -- Macro: LEGITIMIZE_RELOAD_ADDRESS (X, MODE, OPNUM, TYPE, IND_LEVELS, + WIN) + A C compound statement that attempts to replace X, which is an + address that needs reloading, with a valid memory address for an + operand of mode MODE. WIN will be a C statement label elsewhere + in the code. It is not necessary to define this macro, but it + might be useful for performance reasons. + + For example, on the i386, it is sometimes possible to use a single + reload register instead of two by reloading a sum of two pseudo + registers into a register. On the other hand, for number of RISC + processors offsets are limited so that often an intermediate + address needs to be generated in order to address a stack slot. + By defining `LEGITIMIZE_RELOAD_ADDRESS' appropriately, the + intermediate addresses generated for adjacent some stack slots can + be made identical, and thus be shared. + + _Note_: This macro should be used with caution. It is necessary + to know something of how reload works in order to effectively use + this, and it is quite easy to produce macros that build in too + much knowledge of reload internals. + + _Note_: This macro must be able to reload an address created by a + previous invocation of this macro. If it fails to handle such + addresses then the compiler may generate incorrect code or abort. + + The macro definition should use `push_reload' to indicate parts + that need reloading; OPNUM, TYPE and IND_LEVELS are usually + suitable to be passed unaltered to `push_reload'. + + The code generated by this macro must not alter the substructure of + X. If it transforms X into a more legitimate form, it should + assign X (which will always be a C variable) a new value. This + also applies to parts that you change indirectly by calling + `push_reload'. + + The macro definition may use `strict_memory_address_p' to test if + the address has become legitimate. + + If you want to change only a part of X, one standard way of doing + this is to use `copy_rtx'. Note, however, that it unshares only a + single level of rtl. Thus, if the part to be changed is not at the + top level, you'll need to replace first the top level. It is not + necessary for this macro to come up with a legitimate address; + but often a machine-dependent strategy can generate better code. + + -- Target Hook: bool TARGET_MODE_DEPENDENT_ADDRESS_P (const_rtx ADDR) + This hook returns `true' if memory address ADDR can have different + meanings depending on the machine mode of the memory reference it + is used for or if the address is valid for some modes but not + others. + + Autoincrement and autodecrement addresses typically have + mode-dependent effects because the amount of the increment or + decrement is the size of the operand being addressed. Some + machines have other mode-dependent addresses. Many RISC machines + have no mode-dependent addresses. + + You may assume that ADDR is a valid address for the machine. + + The default version of this hook returns `false'. + + -- Macro: GO_IF_MODE_DEPENDENT_ADDRESS (ADDR, LABEL) + A C statement or compound statement with a conditional `goto + LABEL;' executed if memory address X (an RTX) can have different + meanings depending on the machine mode of the memory reference it + is used for or if the address is valid for some modes but not + others. + + Autoincrement and autodecrement addresses typically have + mode-dependent effects because the amount of the increment or + decrement is the size of the operand being addressed. Some + machines have other mode-dependent addresses. Many RISC machines + have no mode-dependent addresses. + + You may assume that ADDR is a valid address for the machine. + + These are obsolete macros, replaced by the + `TARGET_MODE_DEPENDENT_ADDRESS_P' target hook. + + -- Macro: LEGITIMATE_CONSTANT_P (X) + A C expression that is nonzero if X is a legitimate constant for + an immediate operand on the target machine. You can assume that X + satisfies `CONSTANT_P', so you need not check this. In fact, `1' + is a suitable definition for this macro on machines where anything + `CONSTANT_P' is valid. + + -- Target Hook: rtx TARGET_DELEGITIMIZE_ADDRESS (rtx X) + This hook is used to undo the possibly obfuscating effects of the + `LEGITIMIZE_ADDRESS' and `LEGITIMIZE_RELOAD_ADDRESS' target + macros. Some backend implementations of these macros wrap symbol + references inside an `UNSPEC' rtx to represent PIC or similar + addressing modes. This target hook allows GCC's optimizers to + understand the semantics of these opaque `UNSPEC's by converting + them back into their original form. + + -- Target Hook: bool TARGET_CANNOT_FORCE_CONST_MEM (rtx X) + This hook should return true if X is of a form that cannot (or + should not) be spilled to the constant pool. The default version + of this hook returns false. + + The primary reason to define this hook is to prevent reload from + deciding that a non-legitimate constant would be better reloaded + from the constant pool instead of spilling and reloading a register + holding the constant. This restriction is often true of addresses + of TLS symbols for various targets. + + -- Target Hook: bool TARGET_USE_BLOCKS_FOR_CONSTANT_P (enum + machine_mode MODE, const_rtx X) + This hook should return true if pool entries for constant X can be + placed in an `object_block' structure. MODE is the mode of X. + + The default version returns false for all constants. + + -- Target Hook: tree TARGET_BUILTIN_RECIPROCAL (unsigned FN, bool + MD_FN, bool SQRT) + This hook should return the DECL of a function that implements + reciprocal of the builtin function with builtin function code FN, + or `NULL_TREE' if such a function is not available. MD_FN is true + when FN is a code of a machine-dependent builtin function. When + SQRT is true, additional optimizations that apply only to the + reciprocal of a square root function are performed, and only + reciprocals of `sqrt' function are valid. + + -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD (void) + This hook should return the DECL of a function F that given an + address ADDR as an argument returns a mask M that can be used to + extract from two vectors the relevant data that resides in ADDR in + case ADDR is not properly aligned. + + The autovectorizer, when vectorizing a load operation from an + address ADDR that may be unaligned, will generate two vector loads + from the two aligned addresses around ADDR. It then generates a + `REALIGN_LOAD' operation to extract the relevant data from the two + loaded vectors. The first two arguments to `REALIGN_LOAD', V1 and + V2, are the two vectors, each of size VS, and the third argument, + OFF, defines how the data will be extracted from these two + vectors: if OFF is 0, then the returned vector is V2; otherwise, + the returned vector is composed from the last VS-OFF elements of + V1 concatenated to the first OFF elements of V2. + + If this hook is defined, the autovectorizer will generate a call + to F (using the DECL tree that this hook returns) and will use the + return value of F as the argument OFF to `REALIGN_LOAD'. + Therefore, the mask M returned by F should comply with the + semantics expected by `REALIGN_LOAD' described above. If this + hook is not defined, then ADDR will be used as the argument OFF to + `REALIGN_LOAD', in which case the low log2(VS) - 1 bits of ADDR + will be considered. + + -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN (tree X) + This hook should return the DECL of a function F that implements + widening multiplication of the even elements of two input vectors + of type X. + + If this hook is defined, the autovectorizer will use it along with + the `TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD' target hook when + vectorizing widening multiplication in cases that the order of the + results does not have to be preserved (e.g. used only by a + reduction computation). Otherwise, the `widen_mult_hi/lo' idioms + will be used. + + -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD (tree X) + This hook should return the DECL of a function F that implements + widening multiplication of the odd elements of two input vectors + of type X. + + If this hook is defined, the autovectorizer will use it along with + the `TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN' target hook when + vectorizing widening multiplication in cases that the order of the + results does not have to be preserved (e.g. used only by a + reduction computation). Otherwise, the `widen_mult_hi/lo' idioms + will be used. + + -- Target Hook: int TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST (enum + vect_cost_for_stmt TYPE_OF_COST, tree VECTYPE, int MISALIGN) + Returns cost of different scalar or vector statements for + vectorization cost model. For vector memory operations the cost + may depend on type (VECTYPE) and misalignment value (MISALIGN). + + -- Target Hook: bool TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE + (const_tree TYPE, bool IS_PACKED) + Return true if vector alignment is reachable (by peeling N + iterations) for the given type. + + -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_VEC_PERM (tree TYPE, + tree *MASK_ELEMENT_TYPE) + Target builtin that implements vector permute. + + -- Target Hook: bool TARGET_VECTORIZE_BUILTIN_VEC_PERM_OK (tree + VEC_TYPE, tree MASK) + Return true if a vector created for `builtin_vec_perm' is valid. + + -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_CONVERSION (unsigned + CODE, tree DEST_TYPE, tree SRC_TYPE) + This hook should return the DECL of a function that implements + conversion of the input vector of type SRC_TYPE to type DEST_TYPE. + The value of CODE is one of the enumerators in `enum tree_code' and + specifies how the conversion is to be applied (truncation, + rounding, etc.). + + If this hook is defined, the autovectorizer will use the + `TARGET_VECTORIZE_BUILTIN_CONVERSION' target hook when vectorizing + conversion. Otherwise, it will return `NULL_TREE'. + + -- Target Hook: tree TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION + (tree FNDECL, tree VEC_TYPE_OUT, tree VEC_TYPE_IN) + This hook should return the decl of a function that implements the + vectorized variant of the builtin function with builtin function + code CODE or `NULL_TREE' if such a function is not available. The + value of FNDECL is the builtin function declaration. The return + type of the vectorized function shall be of vector type + VEC_TYPE_OUT and the argument types should be VEC_TYPE_IN. + + -- Target Hook: bool TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT + (enum machine_mode MODE, const_tree TYPE, int MISALIGNMENT, + bool IS_PACKED) + This hook should return true if the target supports misaligned + vector store/load of a specific factor denoted in the MISALIGNMENT + parameter. The vector store/load should be of machine mode MODE + and the elements in the vectors should be of type TYPE. IS_PACKED + parameter is true if the memory access is defined in a packed + struct. + + -- Target Hook: enum machine_mode TARGET_VECTORIZE_PREFERRED_SIMD_MODE + (enum machine_mode MODE) + This hook should return the preferred mode for vectorizing scalar + mode MODE. The default is equal to `word_mode', because the + vectorizer can do some transformations even in absence of + specialized SIMD hardware. + + -- Target Hook: unsigned int +TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_SIZES (void) + This hook should return a mask of sizes that should be iterated + over after trying to autovectorize using the vector size derived + from the mode returned by `TARGET_VECTORIZE_PREFERRED_SIMD_MODE'. + The default is zero which means to not iterate over other vector + sizes. + + +File: gccint.info, Node: Anchored Addresses, Next: Condition Code, Prev: Addressing Modes, Up: Target Macros + +17.15 Anchored Addresses +======================== + +GCC usually addresses every static object as a separate entity. For +example, if we have: + + static int a, b, c; + int foo (void) { return a + b + c; } + + the code for `foo' will usually calculate three separate symbolic +addresses: those of `a', `b' and `c'. On some targets, it would be +better to calculate just one symbolic address and access the three +variables relative to it. The equivalent pseudocode would be something +like: + + int foo (void) + { + register int *xr = &x; + return xr[&a - &x] + xr[&b - &x] + xr[&c - &x]; + } + + (which isn't valid C). We refer to shared addresses like `x' as +"section anchors". Their use is controlled by `-fsection-anchors'. + + The hooks below describe the target properties that GCC needs to know +in order to make effective use of section anchors. It won't use +section anchors at all unless either `TARGET_MIN_ANCHOR_OFFSET' or +`TARGET_MAX_ANCHOR_OFFSET' is set to a nonzero value. + + -- Target Hook: HOST_WIDE_INT TARGET_MIN_ANCHOR_OFFSET + The minimum offset that should be applied to a section anchor. On + most targets, it should be the smallest offset that can be applied + to a base register while still giving a legitimate address for + every mode. The default value is 0. + + -- Target Hook: HOST_WIDE_INT TARGET_MAX_ANCHOR_OFFSET + Like `TARGET_MIN_ANCHOR_OFFSET', but the maximum (inclusive) + offset that should be applied to section anchors. The default + value is 0. + + -- Target Hook: void TARGET_ASM_OUTPUT_ANCHOR (rtx X) + Write the assembly code to define section anchor X, which is a + `SYMBOL_REF' for which `SYMBOL_REF_ANCHOR_P (X)' is true. The + hook is called with the assembly output position set to the + beginning of `SYMBOL_REF_BLOCK (X)'. + + If `ASM_OUTPUT_DEF' is available, the hook's default definition + uses it to define the symbol as `. + SYMBOL_REF_BLOCK_OFFSET (X)'. + If `ASM_OUTPUT_DEF' is not available, the hook's default definition + is `NULL', which disables the use of section anchors altogether. + + -- Target Hook: bool TARGET_USE_ANCHORS_FOR_SYMBOL_P (const_rtx X) + Return true if GCC should attempt to use anchors to access + `SYMBOL_REF' X. You can assume `SYMBOL_REF_HAS_BLOCK_INFO_P (X)' + and `!SYMBOL_REF_ANCHOR_P (X)'. + + The default version is correct for most targets, but you might + need to intercept this hook to handle things like target-specific + attributes or target-specific sections. + + +File: gccint.info, Node: Condition Code, Next: Costs, Prev: Anchored Addresses, Up: Target Macros + +17.16 Condition Code Status +=========================== + +The macros in this section can be split in two families, according to +the two ways of representing condition codes in GCC. + + The first representation is the so called `(cc0)' representation +(*note Jump Patterns::), where all instructions can have an implicit +clobber of the condition codes. The second is the condition code +register representation, which provides better schedulability for +architectures that do have a condition code register, but on which most +instructions do not affect it. The latter category includes most RISC +machines. + + The implicit clobbering poses a strong restriction on the placement of +the definition and use of the condition code, which need to be in +adjacent insns for machines using `(cc0)'. This can prevent important +optimizations on some machines. For example, on the IBM RS/6000, there +is a delay for taken branches unless the condition code register is set +three instructions earlier than the conditional branch. The instruction +scheduler cannot perform this optimization if it is not permitted to +separate the definition and use of the condition code register. + + For this reason, it is possible and suggested to use a register to +represent the condition code for new ports. If there is a specific +condition code register in the machine, use a hard register. If the +condition code or comparison result can be placed in any general +register, or if there are multiple condition registers, use a pseudo +register. Registers used to store the condition code value will +usually have a mode that is in class `MODE_CC'. + + Alternatively, you can use `BImode' if the comparison operator is +specified already in the compare instruction. In this case, you are not +interested in most macros in this section. + +* Menu: + +* CC0 Condition Codes:: Old style representation of condition codes. +* MODE_CC Condition Codes:: Modern representation of condition codes. +* Cond Exec Macros:: Macros to control conditional execution. + + +File: gccint.info, Node: CC0 Condition Codes, Next: MODE_CC Condition Codes, Up: Condition Code + +17.16.1 Representation of condition codes using `(cc0)' +------------------------------------------------------- + +The file `conditions.h' defines a variable `cc_status' to describe how +the condition code was computed (in case the interpretation of the +condition code depends on the instruction that it was set by). This +variable contains the RTL expressions on which the condition code is +currently based, and several standard flags. + + Sometimes additional machine-specific flags must be defined in the +machine description header file. It can also add additional +machine-specific information by defining `CC_STATUS_MDEP'. + + -- Macro: CC_STATUS_MDEP + C code for a data type which is used for declaring the `mdep' + component of `cc_status'. It defaults to `int'. + + This macro is not used on machines that do not use `cc0'. + + -- Macro: CC_STATUS_MDEP_INIT + A C expression to initialize the `mdep' field to "empty". The + default definition does nothing, since most machines don't use the + field anyway. If you want to use the field, you should probably + define this macro to initialize it. + + This macro is not used on machines that do not use `cc0'. + + -- Macro: NOTICE_UPDATE_CC (EXP, INSN) + A C compound statement to set the components of `cc_status' + appropriately for an insn INSN whose body is EXP. It is this + macro's responsibility to recognize insns that set the condition + code as a byproduct of other activity as well as those that + explicitly set `(cc0)'. + + This macro is not used on machines that do not use `cc0'. + + If there are insns that do not set the condition code but do alter + other machine registers, this macro must check to see whether they + invalidate the expressions that the condition code is recorded as + reflecting. For example, on the 68000, insns that store in address + registers do not set the condition code, which means that usually + `NOTICE_UPDATE_CC' can leave `cc_status' unaltered for such insns. + But suppose that the previous insn set the condition code based on + location `a4@(102)' and the current insn stores a new value in + `a4'. Although the condition code is not changed by this, it will + no longer be true that it reflects the contents of `a4@(102)'. + Therefore, `NOTICE_UPDATE_CC' must alter `cc_status' in this case + to say that nothing is known about the condition code value. + + The definition of `NOTICE_UPDATE_CC' must be prepared to deal with + the results of peephole optimization: insns whose patterns are + `parallel' RTXs containing various `reg', `mem' or constants which + are just the operands. The RTL structure of these insns is not + sufficient to indicate what the insns actually do. What + `NOTICE_UPDATE_CC' should do when it sees one is just to run + `CC_STATUS_INIT'. + + A possible definition of `NOTICE_UPDATE_CC' is to call a function + that looks at an attribute (*note Insn Attributes::) named, for + example, `cc'. This avoids having detailed information about + patterns in two places, the `md' file and in `NOTICE_UPDATE_CC'. + + +File: gccint.info, Node: MODE_CC Condition Codes, Next: Cond Exec Macros, Prev: CC0 Condition Codes, Up: Condition Code + +17.16.2 Representation of condition codes using registers +--------------------------------------------------------- + + -- Macro: SELECT_CC_MODE (OP, X, Y) + On many machines, the condition code may be produced by other + instructions than compares, for example the branch can use + directly the condition code set by a subtract instruction. + However, on some machines when the condition code is set this way + some bits (such as the overflow bit) are not set in the same way + as a test instruction, so that a different branch instruction must + be used for some conditional branches. When this happens, use the + machine mode of the condition code register to record different + formats of the condition code register. Modes can also be used to + record which compare instruction (e.g. a signed or an unsigned + comparison) produced the condition codes. + + If other modes than `CCmode' are required, add them to + `MACHINE-modes.def' and define `SELECT_CC_MODE' to choose a mode + given an operand of a compare. This is needed because the modes + have to be chosen not only during RTL generation but also, for + example, by instruction combination. The result of + `SELECT_CC_MODE' should be consistent with the mode used in the + patterns; for example to support the case of the add on the SPARC + discussed above, we have the pattern + + (define_insn "" + [(set (reg:CC_NOOV 0) + (compare:CC_NOOV + (plus:SI (match_operand:SI 0 "register_operand" "%r") + (match_operand:SI 1 "arith_operand" "rI")) + (const_int 0)))] + "" + "...") + + together with a `SELECT_CC_MODE' that returns `CC_NOOVmode' for + comparisons whose argument is a `plus': + + #define SELECT_CC_MODE(OP,X,Y) \ + (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT \ + ? ((OP == EQ || OP == NE) ? CCFPmode : CCFPEmode) \ + : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS \ + || GET_CODE (X) == NEG) \ + ? CC_NOOVmode : CCmode)) + + Another reason to use modes is to retain information on which + operands were used by the comparison; see `REVERSIBLE_CC_MODE' + later in this section. + + You should define this macro if and only if you define extra CC + modes in `MACHINE-modes.def'. + + -- Macro: CANONICALIZE_COMPARISON (CODE, OP0, OP1) + On some machines not all possible comparisons are defined, but you + can convert an invalid comparison into a valid one. For example, + the Alpha does not have a `GT' comparison, but you can use an `LT' + comparison instead and swap the order of the operands. + + On such machines, define this macro to be a C statement to do any + required conversions. CODE is the initial comparison code and OP0 + and OP1 are the left and right operands of the comparison, + respectively. You should modify CODE, OP0, and OP1 as required. + + GCC will not assume that the comparison resulting from this macro + is valid but will see if the resulting insn matches a pattern in + the `md' file. + + You need not define this macro if it would never change the + comparison code or operands. + + -- Macro: REVERSIBLE_CC_MODE (MODE) + A C expression whose value is one if it is always safe to reverse a + comparison whose mode is MODE. If `SELECT_CC_MODE' can ever + return MODE for a floating-point inequality comparison, then + `REVERSIBLE_CC_MODE (MODE)' must be zero. + + You need not define this macro if it would always returns zero or + if the floating-point format is anything other than + `IEEE_FLOAT_FORMAT'. For example, here is the definition used on + the SPARC, where floating-point inequality comparisons are always + given `CCFPEmode': + + #define REVERSIBLE_CC_MODE(MODE) ((MODE) != CCFPEmode) + + -- Macro: REVERSE_CONDITION (CODE, MODE) + A C expression whose value is reversed condition code of the CODE + for comparison done in CC_MODE MODE. The macro is used only in + case `REVERSIBLE_CC_MODE (MODE)' is nonzero. Define this macro in + case machine has some non-standard way how to reverse certain + conditionals. For instance in case all floating point conditions + are non-trapping, compiler may freely convert unordered compares + to ordered one. Then definition may look like: + + #define REVERSE_CONDITION(CODE, MODE) \ + ((MODE) != CCFPmode ? reverse_condition (CODE) \ + : reverse_condition_maybe_unordered (CODE)) + + -- Target Hook: bool TARGET_FIXED_CONDITION_CODE_REGS (unsigned int + *P1, unsigned int *P2) + On targets which do not use `(cc0)', and which use a hard register + rather than a pseudo-register to hold condition codes, the regular + CSE passes are often not able to identify cases in which the hard + register is set to a common value. Use this hook to enable a + small pass which optimizes such cases. This hook should return + true to enable this pass, and it should set the integers to which + its arguments point to the hard register numbers used for + condition codes. When there is only one such register, as is true + on most systems, the integer pointed to by P2 should be set to + `INVALID_REGNUM'. + + The default version of this hook returns false. + + -- Target Hook: enum machine_mode TARGET_CC_MODES_COMPATIBLE (enum + machine_mode M1, enum machine_mode M2) + On targets which use multiple condition code modes in class + `MODE_CC', it is sometimes the case that a comparison can be + validly done in more than one mode. On such a system, define this + target hook to take two mode arguments and to return a mode in + which both comparisons may be validly done. If there is no such + mode, return `VOIDmode'. + + The default version of this hook checks whether the modes are the + same. If they are, it returns that mode. If they are different, + it returns `VOIDmode'. + + +File: gccint.info, Node: Cond Exec Macros, Prev: MODE_CC Condition Codes, Up: Condition Code + +17.16.3 Macros to control conditional execution +----------------------------------------------- + +There is one macro that may need to be defined for targets supporting +conditional execution, independent of how they represent conditional +branches. + + -- Macro: REVERSE_CONDEXEC_PREDICATES_P (OP1, OP2) + A C expression that returns true if the conditional execution + predicate OP1, a comparison operation, is the inverse of OP2 and + vice versa. Define this to return 0 if the target has conditional + execution predicates that cannot be reversed safely. There is no + need to validate that the arguments of op1 and op2 are the same, + this is done separately. If no expansion is specified, this macro + is defined as follows: + + #define REVERSE_CONDEXEC_PREDICATES_P (x, y) \ + (GET_CODE ((x)) == reversed_comparison_code ((y), NULL)) + + +File: gccint.info, Node: Costs, Next: Scheduling, Prev: Condition Code, Up: Target Macros + +17.17 Describing Relative Costs of Operations +============================================= + +These macros let you describe the relative speed of various operations +on the target machine. + + -- Macro: REGISTER_MOVE_COST (MODE, FROM, TO) + A C expression for the cost of moving data of mode MODE from a + register in class FROM to one in class TO. The classes are + expressed using the enumeration values such as `GENERAL_REGS'. A + value of 2 is the default; other values are interpreted relative to + that. + + It is not required that the cost always equal 2 when FROM is the + same as TO; on some machines it is expensive to move between + registers if they are not general registers. + + If reload sees an insn consisting of a single `set' between two + hard registers, and if `REGISTER_MOVE_COST' applied to their + classes returns a value of 2, reload does not check to ensure that + the constraints of the insn are met. Setting a cost of other than + 2 will allow reload to verify that the constraints are met. You + should do this if the `movM' pattern's constraints do not allow + such copying. + + These macros are obsolete, new ports should use the target hook + `TARGET_REGISTER_MOVE_COST' instead. + + -- Target Hook: int TARGET_REGISTER_MOVE_COST (enum machine_mode MODE, + reg_class_t FROM, reg_class_t TO) + This target hook should return the cost of moving data of mode MODE + from a register in class FROM to one in class TO. The classes are + expressed using the enumeration values such as `GENERAL_REGS'. A + value of 2 is the default; other values are interpreted relative to + that. + + It is not required that the cost always equal 2 when FROM is the + same as TO; on some machines it is expensive to move between + registers if they are not general registers. + + If reload sees an insn consisting of a single `set' between two + hard registers, and if `TARGET_REGISTER_MOVE_COST' applied to their + classes returns a value of 2, reload does not check to ensure that + the constraints of the insn are met. Setting a cost of other than + 2 will allow reload to verify that the constraints are met. You + should do this if the `movM' pattern's constraints do not allow + such copying. + + The default version of this function returns 2. + + -- Macro: MEMORY_MOVE_COST (MODE, CLASS, IN) + A C expression for the cost of moving data of mode MODE between a + register of class CLASS and memory; IN is zero if the value is to + be written to memory, nonzero if it is to be read in. This cost + is relative to those in `REGISTER_MOVE_COST'. If moving between + registers and memory is more expensive than between two registers, + you should define this macro to express the relative cost. + + If you do not define this macro, GCC uses a default cost of 4 plus + the cost of copying via a secondary reload register, if one is + needed. If your machine requires a secondary reload register to + copy between memory and a register of CLASS but the reload + mechanism is more complex than copying via an intermediate, define + this macro to reflect the actual cost of the move. + + GCC defines the function `memory_move_secondary_cost' if secondary + reloads are needed. It computes the costs due to copying via a + secondary register. If your machine copies from memory using a + secondary register in the conventional way but the default base + value of 4 is not correct for your machine, define this macro to + add some other value to the result of that function. The + arguments to that function are the same as to this macro. + + These macros are obsolete, new ports should use the target hook + `TARGET_MEMORY_MOVE_COST' instead. + + -- Target Hook: int TARGET_MEMORY_MOVE_COST (enum machine_mode MODE, + reg_class_t RCLASS, bool IN) + This target hook should return the cost of moving data of mode MODE + between a register of class RCLASS and memory; IN is `false' if + the value is to be written to memory, `true' if it is to be read + in. This cost is relative to those in `TARGET_REGISTER_MOVE_COST'. + If moving between registers and memory is more expensive than + between two registers, you should add this target hook to express + the relative cost. + + If you do not add this target hook, GCC uses a default cost of 4 + plus the cost of copying via a secondary reload register, if one is + needed. If your machine requires a secondary reload register to + copy between memory and a register of RCLASS but the reload + mechanism is more complex than copying via an intermediate, use + this target hook to reflect the actual cost of the move. + + GCC defines the function `memory_move_secondary_cost' if secondary + reloads are needed. It computes the costs due to copying via a + secondary register. If your machine copies from memory using a + secondary register in the conventional way but the default base + value of 4 is not correct for your machine, use this target hook + to add some other value to the result of that function. The + arguments to that function are the same as to this target hook. + + -- Macro: BRANCH_COST (SPEED_P, PREDICTABLE_P) + A C expression for the cost of a branch instruction. A value of 1 + is the default; other values are interpreted relative to that. + Parameter SPEED_P is true when the branch in question should be + optimized for speed. When it is false, `BRANCH_COST' should + return a value optimal for code size rather than performance. + PREDICTABLE_P is true for well-predicted branches. On many + architectures the `BRANCH_COST' can be reduced then. + + Here are additional macros which do not specify precise relative costs, +but only that certain actions are more expensive than GCC would +ordinarily expect. + + -- Macro: SLOW_BYTE_ACCESS + Define this macro as a C expression which is nonzero if accessing + less than a word of memory (i.e. a `char' or a `short') is no + faster than accessing a word of memory, i.e., if such access + require more than one instruction or if there is no difference in + cost between byte and (aligned) word loads. + + When this macro is not defined, the compiler will access a field by + finding the smallest containing object; when it is defined, a + fullword load will be used if alignment permits. Unless bytes + accesses are faster than word accesses, using word accesses is + preferable since it may eliminate subsequent memory access if + subsequent accesses occur to other fields in the same word of the + structure, but to different bytes. + + -- Macro: SLOW_UNALIGNED_ACCESS (MODE, ALIGNMENT) + Define this macro to be the value 1 if memory accesses described + by the MODE and ALIGNMENT parameters have a cost many times greater + than aligned accesses, for example if they are emulated in a trap + handler. + + When this macro is nonzero, the compiler will act as if + `STRICT_ALIGNMENT' were nonzero when generating code for block + moves. This can cause significantly more instructions to be + produced. Therefore, do not set this macro nonzero if unaligned + accesses only add a cycle or two to the time for a memory access. + + If the value of this macro is always zero, it need not be defined. + If this macro is defined, it should produce a nonzero value when + `STRICT_ALIGNMENT' is nonzero. + + -- Macro: MOVE_RATIO (SPEED) + The threshold of number of scalar memory-to-memory move insns, + _below_ which a sequence of insns should be generated instead of a + string move insn or a library call. Increasing the value will + always make code faster, but eventually incurs high cost in + increased code size. + + Note that on machines where the corresponding move insn is a + `define_expand' that emits a sequence of insns, this macro counts + the number of such sequences. + + The parameter SPEED is true if the code is currently being + optimized for speed rather than size. + + If you don't define this, a reasonable default is used. + + -- Macro: MOVE_BY_PIECES_P (SIZE, ALIGNMENT) + A C expression used to determine whether `move_by_pieces' will be + used to copy a chunk of memory, or whether some other block move + mechanism will be used. Defaults to 1 if `move_by_pieces_ninsns' + returns less than `MOVE_RATIO'. + + -- Macro: MOVE_MAX_PIECES + A C expression used by `move_by_pieces' to determine the largest + unit a load or store used to copy memory is. Defaults to + `MOVE_MAX'. + + -- Macro: CLEAR_RATIO (SPEED) + The threshold of number of scalar move insns, _below_ which a + sequence of insns should be generated to clear memory instead of a + string clear insn or a library call. Increasing the value will + always make code faster, but eventually incurs high cost in + increased code size. + + The parameter SPEED is true if the code is currently being + optimized for speed rather than size. + + If you don't define this, a reasonable default is used. + + -- Macro: CLEAR_BY_PIECES_P (SIZE, ALIGNMENT) + A C expression used to determine whether `clear_by_pieces' will be + used to clear a chunk of memory, or whether some other block clear + mechanism will be used. Defaults to 1 if `move_by_pieces_ninsns' + returns less than `CLEAR_RATIO'. + + -- Macro: SET_RATIO (SPEED) + The threshold of number of scalar move insns, _below_ which a + sequence of insns should be generated to set memory to a constant + value, instead of a block set insn or a library call. Increasing + the value will always make code faster, but eventually incurs high + cost in increased code size. + + The parameter SPEED is true if the code is currently being + optimized for speed rather than size. + + If you don't define this, it defaults to the value of `MOVE_RATIO'. + + -- Macro: SET_BY_PIECES_P (SIZE, ALIGNMENT) + A C expression used to determine whether `store_by_pieces' will be + used to set a chunk of memory to a constant value, or whether some + other mechanism will be used. Used by `__builtin_memset' when + storing values other than constant zero. Defaults to 1 if + `move_by_pieces_ninsns' returns less than `SET_RATIO'. + + -- Macro: STORE_BY_PIECES_P (SIZE, ALIGNMENT) + A C expression used to determine whether `store_by_pieces' will be + used to set a chunk of memory to a constant string value, or + whether some other mechanism will be used. Used by + `__builtin_strcpy' when called with a constant source string. + Defaults to 1 if `move_by_pieces_ninsns' returns less than + `MOVE_RATIO'. + + -- Macro: USE_LOAD_POST_INCREMENT (MODE) + A C expression used to determine whether a load postincrement is a + good thing to use for a given mode. Defaults to the value of + `HAVE_POST_INCREMENT'. + + -- Macro: USE_LOAD_POST_DECREMENT (MODE) + A C expression used to determine whether a load postdecrement is a + good thing to use for a given mode. Defaults to the value of + `HAVE_POST_DECREMENT'. + + -- Macro: USE_LOAD_PRE_INCREMENT (MODE) + A C expression used to determine whether a load preincrement is a + good thing to use for a given mode. Defaults to the value of + `HAVE_PRE_INCREMENT'. + + -- Macro: USE_LOAD_PRE_DECREMENT (MODE) + A C expression used to determine whether a load predecrement is a + good thing to use for a given mode. Defaults to the value of + `HAVE_PRE_DECREMENT'. + + -- Macro: USE_STORE_POST_INCREMENT (MODE) + A C expression used to determine whether a store postincrement is + a good thing to use for a given mode. Defaults to the value of + `HAVE_POST_INCREMENT'. + + -- Macro: USE_STORE_POST_DECREMENT (MODE) + A C expression used to determine whether a store postdecrement is + a good thing to use for a given mode. Defaults to the value of + `HAVE_POST_DECREMENT'. + + -- Macro: USE_STORE_PRE_INCREMENT (MODE) + This macro is used to determine whether a store preincrement is a + good thing to use for a given mode. Defaults to the value of + `HAVE_PRE_INCREMENT'. + + -- Macro: USE_STORE_PRE_DECREMENT (MODE) + This macro is used to determine whether a store predecrement is a + good thing to use for a given mode. Defaults to the value of + `HAVE_PRE_DECREMENT'. + + -- Macro: NO_FUNCTION_CSE + Define this macro if it is as good or better to call a constant + function address than to call an address kept in a register. + + -- Macro: RANGE_TEST_NON_SHORT_CIRCUIT + Define this macro if a non-short-circuit operation produced by + `fold_range_test ()' is optimal. This macro defaults to true if + `BRANCH_COST' is greater than or equal to the value 2. + + -- Target Hook: bool TARGET_RTX_COSTS (rtx X, int CODE, int + OUTER_CODE, int *TOTAL, bool SPEED) + This target hook describes the relative costs of RTL expressions. + + The cost may depend on the precise form of the expression, which is + available for examination in X, and the rtx code of the expression + in which it is contained, found in OUTER_CODE. CODE is the + expression code--redundant, since it can be obtained with + `GET_CODE (X)'. + + In implementing this hook, you can use the construct + `COSTS_N_INSNS (N)' to specify a cost equal to N fast instructions. + + On entry to the hook, `*TOTAL' contains a default estimate for the + cost of the expression. The hook should modify this value as + necessary. Traditionally, the default costs are `COSTS_N_INSNS + (5)' for multiplications, `COSTS_N_INSNS (7)' for division and + modulus operations, and `COSTS_N_INSNS (1)' for all other + operations. + + When optimizing for code size, i.e. when `speed' is false, this + target hook should be used to estimate the relative size cost of + an expression, again relative to `COSTS_N_INSNS'. + + The hook returns true when all subexpressions of X have been + processed, and false when `rtx_cost' should recurse. + + -- Target Hook: int TARGET_ADDRESS_COST (rtx ADDRESS, bool SPEED) + This hook computes the cost of an addressing mode that contains + ADDRESS. If not defined, the cost is computed from the ADDRESS + expression and the `TARGET_RTX_COST' hook. + + For most CISC machines, the default cost is a good approximation + of the true cost of the addressing mode. However, on RISC + machines, all instructions normally have the same length and + execution time. Hence all addresses will have equal costs. + + In cases where more than one form of an address is known, the form + with the lowest cost will be used. If multiple forms have the + same, lowest, cost, the one that is the most complex will be used. + + For example, suppose an address that is equal to the sum of a + register and a constant is used twice in the same basic block. + When this macro is not defined, the address will be computed in a + register and memory references will be indirect through that + register. On machines where the cost of the addressing mode + containing the sum is no higher than that of a simple indirect + reference, this will produce an additional instruction and + possibly require an additional register. Proper specification of + this macro eliminates this overhead for such machines. + + This hook is never called with an invalid address. + + On machines where an address involving more than one register is as + cheap as an address computation involving only one register, + defining `TARGET_ADDRESS_COST' to reflect this can cause two + registers to be live over a region of code where only one would + have been if `TARGET_ADDRESS_COST' were not defined in that + manner. This effect should be considered in the definition of + this macro. Equivalent costs should probably only be given to + addresses with different numbers of registers on machines with + lots of registers. + + +File: gccint.info, Node: Scheduling, Next: Sections, Prev: Costs, Up: Target Macros + +17.18 Adjusting the Instruction Scheduler +========================================= + +The instruction scheduler may need a fair amount of machine-specific +adjustment in order to produce good code. GCC provides several target +hooks for this purpose. It is usually enough to define just a few of +them: try the first ones in this list first. + + -- Target Hook: int TARGET_SCHED_ISSUE_RATE (void) + This hook returns the maximum number of instructions that can ever + issue at the same time on the target machine. The default is one. + Although the insn scheduler can define itself the possibility of + issue an insn on the same cycle, the value can serve as an + additional constraint to issue insns on the same simulated + processor cycle (see hooks `TARGET_SCHED_REORDER' and + `TARGET_SCHED_REORDER2'). This value must be constant over the + entire compilation. If you need it to vary depending on what the + instructions are, you must use `TARGET_SCHED_VARIABLE_ISSUE'. + + -- Target Hook: int TARGET_SCHED_VARIABLE_ISSUE (FILE *FILE, int + VERBOSE, rtx INSN, int MORE) + This hook is executed by the scheduler after it has scheduled an + insn from the ready list. It should return the number of insns + which can still be issued in the current cycle. The default is + `MORE - 1' for insns other than `CLOBBER' and `USE', which + normally are not counted against the issue rate. You should + define this hook if some insns take more machine resources than + others, so that fewer insns can follow them in the same cycle. + FILE is either a null pointer, or a stdio stream to write any + debug output to. VERBOSE is the verbose level provided by + `-fsched-verbose-N'. INSN is the instruction that was scheduled. + + -- Target Hook: int TARGET_SCHED_ADJUST_COST (rtx INSN, rtx LINK, rtx + DEP_INSN, int COST) + This function corrects the value of COST based on the relationship + between INSN and DEP_INSN through the dependence LINK. It should + return the new value. The default is to make no adjustment to + COST. This can be used for example to specify to the scheduler + using the traditional pipeline description that an output- or + anti-dependence does not incur the same cost as a data-dependence. + If the scheduler using the automaton based pipeline description, + the cost of anti-dependence is zero and the cost of + output-dependence is maximum of one and the difference of latency + times of the first and the second insns. If these values are not + acceptable, you could use the hook to modify them too. See also + *note Processor pipeline description::. + + -- Target Hook: int TARGET_SCHED_ADJUST_PRIORITY (rtx INSN, int + PRIORITY) + This hook adjusts the integer scheduling priority PRIORITY of + INSN. It should return the new priority. Increase the priority to + execute INSN earlier, reduce the priority to execute INSN later. + Do not define this hook if you do not need to adjust the + scheduling priorities of insns. + + -- Target Hook: int TARGET_SCHED_REORDER (FILE *FILE, int VERBOSE, rtx + *READY, int *N_READYP, int CLOCK) + This hook is executed by the scheduler after it has scheduled the + ready list, to allow the machine description to reorder it (for + example to combine two small instructions together on `VLIW' + machines). FILE is either a null pointer, or a stdio stream to + write any debug output to. VERBOSE is the verbose level provided + by `-fsched-verbose-N'. READY is a pointer to the ready list of + instructions that are ready to be scheduled. N_READYP is a + pointer to the number of elements in the ready list. The scheduler + reads the ready list in reverse order, starting with + READY[*N_READYP - 1] and going to READY[0]. CLOCK is the timer + tick of the scheduler. You may modify the ready list and the + number of ready insns. The return value is the number of insns + that can issue this cycle; normally this is just `issue_rate'. + See also `TARGET_SCHED_REORDER2'. + + -- Target Hook: int TARGET_SCHED_REORDER2 (FILE *FILE, int VERBOSE, + rtx *READY, int *N_READYP, int CLOCK) + Like `TARGET_SCHED_REORDER', but called at a different time. That + function is called whenever the scheduler starts a new cycle. + This one is called once per iteration over a cycle, immediately + after `TARGET_SCHED_VARIABLE_ISSUE'; it can reorder the ready list + and return the number of insns to be scheduled in the same cycle. + Defining this hook can be useful if there are frequent situations + where scheduling one insn causes other insns to become ready in + the same cycle. These other insns can then be taken into account + properly. + + -- Target Hook: void TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK (rtx + HEAD, rtx TAIL) + This hook is called after evaluation forward dependencies of insns + in chain given by two parameter values (HEAD and TAIL + correspondingly) but before insns scheduling of the insn chain. + For example, it can be used for better insn classification if it + requires analysis of dependencies. This hook can use backward and + forward dependencies of the insn scheduler because they are already + calculated. + + -- Target Hook: void TARGET_SCHED_INIT (FILE *FILE, int VERBOSE, int + MAX_READY) + This hook is executed by the scheduler at the beginning of each + block of instructions that are to be scheduled. FILE is either a + null pointer, or a stdio stream to write any debug output to. + VERBOSE is the verbose level provided by `-fsched-verbose-N'. + MAX_READY is the maximum number of insns in the current scheduling + region that can be live at the same time. This can be used to + allocate scratch space if it is needed, e.g. by + `TARGET_SCHED_REORDER'. + + -- Target Hook: void TARGET_SCHED_FINISH (FILE *FILE, int VERBOSE) + This hook is executed by the scheduler at the end of each block of + instructions that are to be scheduled. It can be used to perform + cleanup of any actions done by the other scheduling hooks. FILE + is either a null pointer, or a stdio stream to write any debug + output to. VERBOSE is the verbose level provided by + `-fsched-verbose-N'. + + -- Target Hook: void TARGET_SCHED_INIT_GLOBAL (FILE *FILE, int + VERBOSE, int OLD_MAX_UID) + This hook is executed by the scheduler after function level + initializations. FILE is either a null pointer, or a stdio stream + to write any debug output to. VERBOSE is the verbose level + provided by `-fsched-verbose-N'. OLD_MAX_UID is the maximum insn + uid when scheduling begins. + + -- Target Hook: void TARGET_SCHED_FINISH_GLOBAL (FILE *FILE, int + VERBOSE) + This is the cleanup hook corresponding to + `TARGET_SCHED_INIT_GLOBAL'. FILE is either a null pointer, or a + stdio stream to write any debug output to. VERBOSE is the verbose + level provided by `-fsched-verbose-N'. + + -- Target Hook: rtx TARGET_SCHED_DFA_PRE_CYCLE_INSN (void) + The hook returns an RTL insn. The automaton state used in the + pipeline hazard recognizer is changed as if the insn were scheduled + when the new simulated processor cycle starts. Usage of the hook + may simplify the automaton pipeline description for some VLIW + processors. If the hook is defined, it is used only for the + automaton based pipeline description. The default is not to + change the state when the new simulated processor cycle starts. + + -- Target Hook: void TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN (void) + The hook can be used to initialize data used by the previous hook. + + -- Target Hook: rtx TARGET_SCHED_DFA_POST_CYCLE_INSN (void) + The hook is analogous to `TARGET_SCHED_DFA_PRE_CYCLE_INSN' but used + to changed the state as if the insn were scheduled when the new + simulated processor cycle finishes. + + -- Target Hook: void TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN (void) + The hook is analogous to `TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN' but + used to initialize data used by the previous hook. + + -- Target Hook: void TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE (void) + The hook to notify target that the current simulated cycle is + about to finish. The hook is analogous to + `TARGET_SCHED_DFA_PRE_CYCLE_INSN' but used to change the state in + more complicated situations - e.g., when advancing state on a + single insn is not enough. + + -- Target Hook: void TARGET_SCHED_DFA_POST_ADVANCE_CYCLE (void) + The hook to notify target that new simulated cycle has just + started. The hook is analogous to + `TARGET_SCHED_DFA_POST_CYCLE_INSN' but used to change the state in + more complicated situations - e.g., when advancing state on a + single insn is not enough. + + -- Target Hook: int TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD + (void) + This hook controls better choosing an insn from the ready insn + queue for the DFA-based insn scheduler. Usually the scheduler + chooses the first insn from the queue. If the hook returns a + positive value, an additional scheduler code tries all + permutations of `TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD + ()' subsequent ready insns to choose an insn whose issue will + result in maximal number of issued insns on the same cycle. For + the VLIW processor, the code could actually solve the problem of + packing simple insns into the VLIW insn. Of course, if the rules + of VLIW packing are described in the automaton. + + This code also could be used for superscalar RISC processors. Let + us consider a superscalar RISC processor with 3 pipelines. Some + insns can be executed in pipelines A or B, some insns can be + executed only in pipelines B or C, and one insn can be executed in + pipeline B. The processor may issue the 1st insn into A and the + 2nd one into B. In this case, the 3rd insn will wait for freeing B + until the next cycle. If the scheduler issues the 3rd insn the + first, the processor could issue all 3 insns per cycle. + + Actually this code demonstrates advantages of the automaton based + pipeline hazard recognizer. We try quickly and easy many insn + schedules to choose the best one. + + The default is no multipass scheduling. + + -- Target Hook: int +TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD (rtx INSN) + This hook controls what insns from the ready insn queue will be + considered for the multipass insn scheduling. If the hook returns + zero for INSN, the insn will be not chosen to be issued. + + The default is that any ready insns can be chosen to be issued. + + -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN (void + *DATA, char *READY_TRY, int N_READY, bool FIRST_CYCLE_INSN_P) + This hook prepares the target backend for a new round of multipass + scheduling. + + -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE (void + *DATA, char *READY_TRY, int N_READY, rtx INSN, const void + *PREV_DATA) + This hook is called when multipass scheduling evaluates + instruction INSN. + + -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK + (const void *DATA, char *READY_TRY, int N_READY) + This is called when multipass scheduling backtracks from + evaluation of an instruction. + + -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END (const + void *DATA) + This hook notifies the target about the result of the concluded + current round of multipass scheduling. + + -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT (void + *DATA) + This hook initializes target-specific data used in multipass + scheduling. + + -- Target Hook: void TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI (void + *DATA) + This hook finalizes target-specific data used in multipass + scheduling. + + -- Target Hook: int TARGET_SCHED_DFA_NEW_CYCLE (FILE *DUMP, int + VERBOSE, rtx INSN, int LAST_CLOCK, int CLOCK, int *SORT_P) + This hook is called by the insn scheduler before issuing INSN on + cycle CLOCK. If the hook returns nonzero, INSN is not issued on + this processor cycle. Instead, the processor cycle is advanced. + If *SORT_P is zero, the insn ready queue is not sorted on the new + cycle start as usually. DUMP and VERBOSE specify the file and + verbosity level to use for debugging output. LAST_CLOCK and CLOCK + are, respectively, the processor cycle on which the previous insn + has been issued, and the current processor cycle. + + -- Target Hook: bool TARGET_SCHED_IS_COSTLY_DEPENDENCE (struct _dep + *_DEP, int COST, int DISTANCE) + This hook is used to define which dependences are considered + costly by the target, so costly that it is not advisable to + schedule the insns that are involved in the dependence too close + to one another. The parameters to this hook are as follows: The + first parameter _DEP is the dependence being evaluated. The + second parameter COST is the cost of the dependence as estimated + by the scheduler, and the third parameter DISTANCE is the distance + in cycles between the two insns. The hook returns `true' if + considering the distance between the two insns the dependence + between them is considered costly by the target, and `false' + otherwise. + + Defining this hook can be useful in multiple-issue out-of-order + machines, where (a) it's practically hopeless to predict the + actual data/resource delays, however: (b) there's a better chance + to predict the actual grouping that will be formed, and (c) + correctly emulating the grouping can be very important. In such + targets one may want to allow issuing dependent insns closer to + one another--i.e., closer than the dependence distance; however, + not in cases of "costly dependences", which this hooks allows to + define. + + -- Target Hook: void TARGET_SCHED_H_I_D_EXTENDED (void) + This hook is called by the insn scheduler after emitting a new + instruction to the instruction stream. The hook notifies a target + backend to extend its per instruction data structures. + + -- Target Hook: void * TARGET_SCHED_ALLOC_SCHED_CONTEXT (void) + Return a pointer to a store large enough to hold target scheduling + context. + + -- Target Hook: void TARGET_SCHED_INIT_SCHED_CONTEXT (void *TC, bool + CLEAN_P) + Initialize store pointed to by TC to hold target scheduling + context. It CLEAN_P is true then initialize TC as if scheduler is + at the beginning of the block. Otherwise, copy the current + context into TC. + + -- Target Hook: void TARGET_SCHED_SET_SCHED_CONTEXT (void *TC) + Copy target scheduling context pointed to by TC to the current + context. + + -- Target Hook: void TARGET_SCHED_CLEAR_SCHED_CONTEXT (void *TC) + Deallocate internal data in target scheduling context pointed to + by TC. + + -- Target Hook: void TARGET_SCHED_FREE_SCHED_CONTEXT (void *TC) + Deallocate a store for target scheduling context pointed to by TC. + + -- Target Hook: int TARGET_SCHED_SPECULATE_INSN (rtx INSN, int + REQUEST, rtx *NEW_PAT) + This hook is called by the insn scheduler when INSN has only + speculative dependencies and therefore can be scheduled + speculatively. The hook is used to check if the pattern of INSN + has a speculative version and, in case of successful check, to + generate that speculative pattern. The hook should return 1, if + the instruction has a speculative form, or -1, if it doesn't. + REQUEST describes the type of requested speculation. If the + return value equals 1 then NEW_PAT is assigned the generated + speculative pattern. + + -- Target Hook: bool TARGET_SCHED_NEEDS_BLOCK_P (int DEP_STATUS) + This hook is called by the insn scheduler during generation of + recovery code for INSN. It should return `true', if the + corresponding check instruction should branch to recovery code, or + `false' otherwise. + + -- Target Hook: rtx TARGET_SCHED_GEN_SPEC_CHECK (rtx INSN, rtx LABEL, + int MUTATE_P) + This hook is called by the insn scheduler to generate a pattern + for recovery check instruction. If MUTATE_P is zero, then INSN is + a speculative instruction for which the check should be generated. + LABEL is either a label of a basic block, where recovery code + should be emitted, or a null pointer, when requested check doesn't + branch to recovery code (a simple check). If MUTATE_P is nonzero, + then a pattern for a branchy check corresponding to a simple check + denoted by INSN should be generated. In this case LABEL can't be + null. + + -- Target Hook: bool +TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC (const_rtx + INSN) + This hook is used as a workaround for + `TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD' not being + called on the first instruction of the ready list. The hook is + used to discard speculative instructions that stand first in the + ready list from being scheduled on the current cycle. If the hook + returns `false', INSN will not be chosen to be issued. For + non-speculative instructions, the hook should always return + `true'. For example, in the ia64 backend the hook is used to + cancel data speculative insns when the ALAT table is nearly full. + + -- Target Hook: void TARGET_SCHED_SET_SCHED_FLAGS (struct + spec_info_def *SPEC_INFO) + This hook is used by the insn scheduler to find out what features + should be enabled/used. The structure *SPEC_INFO should be filled + in by the target. The structure describes speculation types that + can be used in the scheduler. + + -- Target Hook: int TARGET_SCHED_SMS_RES_MII (struct ddg *G) + This hook is called by the swing modulo scheduler to calculate a + resource-based lower bound which is based on the resources + available in the machine and the resources required by each + instruction. The target backend can use G to calculate such + bound. A very simple lower bound will be used in case this hook + is not implemented: the total number of instructions divided by + the issue rate. + + -- Target Hook: bool TARGET_SCHED_DISPATCH (rtx INSN, int X) + This hook is called by Haifa Scheduler. It returns true if + dispatch scheduling is supported in hardware and the condition + specified in the parameter is true. + + -- Target Hook: void TARGET_SCHED_DISPATCH_DO (rtx INSN, int X) + This hook is called by Haifa Scheduler. It performs the operation + specified in its second parameter. + + +File: gccint.info, Node: Sections, Next: PIC, Prev: Scheduling, Up: Target Macros + +17.19 Dividing the Output into Sections (Texts, Data, ...) +========================================================== + +An object file is divided into sections containing different types of +data. In the most common case, there are three sections: the "text +section", which holds instructions and read-only data; the "data +section", which holds initialized writable data; and the "bss section", +which holds uninitialized data. Some systems have other kinds of +sections. + + `varasm.c' provides several well-known sections, such as +`text_section', `data_section' and `bss_section'. The normal way of +controlling a `FOO_section' variable is to define the associated +`FOO_SECTION_ASM_OP' macro, as described below. The macros are only +read once, when `varasm.c' initializes itself, so their values must be +run-time constants. They may however depend on command-line flags. + + _Note:_ Some run-time files, such `crtstuff.c', also make use of the +`FOO_SECTION_ASM_OP' macros, and expect them to be string literals. + + Some assemblers require a different string to be written every time a +section is selected. If your assembler falls into this category, you +should define the `TARGET_ASM_INIT_SECTIONS' hook and use +`get_unnamed_section' to set up the sections. + + You must always create a `text_section', either by defining +`TEXT_SECTION_ASM_OP' or by initializing `text_section' in +`TARGET_ASM_INIT_SECTIONS'. The same is true of `data_section' and +`DATA_SECTION_ASM_OP'. If you do not create a distinct +`readonly_data_section', the default is to reuse `text_section'. + + All the other `varasm.c' sections are optional, and are null if the +target does not provide them. + + -- Macro: TEXT_SECTION_ASM_OP + A C expression whose value is a string, including spacing, + containing the assembler operation that should precede + instructions and read-only data. Normally `"\t.text"' is right. + + -- Macro: HOT_TEXT_SECTION_NAME + If defined, a C string constant for the name of the section + containing most frequently executed functions of the program. If + not defined, GCC will provide a default definition if the target + supports named sections. + + -- Macro: UNLIKELY_EXECUTED_TEXT_SECTION_NAME + If defined, a C string constant for the name of the section + containing unlikely executed functions in the program. + + -- Macro: DATA_SECTION_ASM_OP + A C expression whose value is a string, including spacing, + containing the assembler operation to identify the following data + as writable initialized data. Normally `"\t.data"' is right. + + -- Macro: SDATA_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as initialized, writable small data. + + -- Macro: READONLY_DATA_SECTION_ASM_OP + A C expression whose value is a string, including spacing, + containing the assembler operation to identify the following data + as read-only initialized data. + + -- Macro: BSS_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as uninitialized global data. If not defined, and + neither `ASM_OUTPUT_BSS' nor `ASM_OUTPUT_ALIGNED_BSS' are defined, + uninitialized global data will be output in the data section if + `-fno-common' is passed, otherwise `ASM_OUTPUT_COMMON' will be + used. + + -- Macro: SBSS_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as uninitialized, writable small data. + + -- Macro: TLS_COMMON_ASM_OP + If defined, a C expression whose value is a string containing the + assembler operation to identify the following data as thread-local + common data. The default is `".tls_common"'. + + -- Macro: TLS_SECTION_ASM_FLAG + If defined, a C expression whose value is a character constant + containing the flag used to mark a section as a TLS section. The + default is `'T''. + + -- Macro: INIT_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as initialization code. If not defined, GCC will + assume such a section does not exist. This section has no + corresponding `init_section' variable; it is used entirely in + runtime code. + + -- Macro: FINI_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as finalization code. If not defined, GCC will + assume such a section does not exist. This section has no + corresponding `fini_section' variable; it is used entirely in + runtime code. + + -- Macro: INIT_ARRAY_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as part of the `.init_array' (or equivalent) + section. If not defined, GCC will assume such a section does not + exist. Do not define both this macro and `INIT_SECTION_ASM_OP'. + + -- Macro: FINI_ARRAY_SECTION_ASM_OP + If defined, a C expression whose value is a string, including + spacing, containing the assembler operation to identify the + following data as part of the `.fini_array' (or equivalent) + section. If not defined, GCC will assume such a section does not + exist. Do not define both this macro and `FINI_SECTION_ASM_OP'. + + -- Macro: CRT_CALL_STATIC_FUNCTION (SECTION_OP, FUNCTION) + If defined, an ASM statement that switches to a different section + via SECTION_OP, calls FUNCTION, and switches back to the text + section. This is used in `crtstuff.c' if `INIT_SECTION_ASM_OP' or + `FINI_SECTION_ASM_OP' to calls to initialization and finalization + functions from the init and fini sections. By default, this macro + uses a simple function call. Some ports need hand-crafted + assembly code to avoid dependencies on registers initialized in + the function prologue or to ensure that constant pools don't end + up too far way in the text section. + + -- Macro: TARGET_LIBGCC_SDATA_SECTION + If defined, a string which names the section into which small + variables defined in crtstuff and libgcc should go. This is useful + when the target has options for optimizing access to small data, + and you want the crtstuff and libgcc routines to be conservative + in what they expect of your application yet liberal in what your + application expects. For example, for targets with a `.sdata' + section (like MIPS), you could compile crtstuff with `-G 0' so + that it doesn't require small data support from your application, + but use this macro to put small data into `.sdata' so that your + application can access these variables whether it uses small data + or not. + + -- Macro: FORCE_CODE_SECTION_ALIGN + If defined, an ASM statement that aligns a code section to some + arbitrary boundary. This is used to force all fragments of the + `.init' and `.fini' sections to have to same alignment and thus + prevent the linker from having to add any padding. + + -- Macro: JUMP_TABLES_IN_TEXT_SECTION + Define this macro to be an expression with a nonzero value if jump + tables (for `tablejump' insns) should be output in the text + section, along with the assembler instructions. Otherwise, the + readonly data section is used. + + This macro is irrelevant if there is no separate readonly data + section. + + -- Target Hook: void TARGET_ASM_INIT_SECTIONS (void) + Define this hook if you need to do something special to set up the + `varasm.c' sections, or if your target has some special sections + of its own that you need to create. + + GCC calls this hook after processing the command line, but before + writing any assembly code, and before calling any of the + section-returning hooks described below. + + -- Target Hook: int TARGET_ASM_RELOC_RW_MASK (void) + Return a mask describing how relocations should be treated when + selecting sections. Bit 1 should be set if global relocations + should be placed in a read-write section; bit 0 should be set if + local relocations should be placed in a read-write section. + + The default version of this function returns 3 when `-fpic' is in + effect, and 0 otherwise. The hook is typically redefined when the + target cannot support (some kinds of) dynamic relocations in + read-only sections even in executables. + + -- Target Hook: section * TARGET_ASM_SELECT_SECTION (tree EXP, int + RELOC, unsigned HOST_WIDE_INT ALIGN) + Return the section into which EXP should be placed. You can + assume that EXP is either a `VAR_DECL' node or a constant of some + sort. RELOC indicates whether the initial value of EXP requires + link-time relocations. Bit 0 is set when variable contains local + relocations only, while bit 1 is set for global relocations. + ALIGN is the constant alignment in bits. + + The default version of this function takes care of putting + read-only variables in `readonly_data_section'. + + See also USE_SELECT_SECTION_FOR_FUNCTIONS. + + -- Macro: USE_SELECT_SECTION_FOR_FUNCTIONS + Define this macro if you wish TARGET_ASM_SELECT_SECTION to be + called for `FUNCTION_DECL's as well as for variables and constants. + + In the case of a `FUNCTION_DECL', RELOC will be zero if the + function has been determined to be likely to be called, and + nonzero if it is unlikely to be called. + + -- Target Hook: void TARGET_ASM_UNIQUE_SECTION (tree DECL, int RELOC) + Build up a unique section name, expressed as a `STRING_CST' node, + and assign it to `DECL_SECTION_NAME (DECL)'. As with + `TARGET_ASM_SELECT_SECTION', RELOC indicates whether the initial + value of EXP requires link-time relocations. + + The default version of this function appends the symbol name to the + ELF section name that would normally be used for the symbol. For + example, the function `foo' would be placed in `.text.foo'. + Whatever the actual target object format, this is often good + enough. + + -- Target Hook: section * TARGET_ASM_FUNCTION_RODATA_SECTION (tree + DECL) + Return the readonly data section associated with + `DECL_SECTION_NAME (DECL)'. The default version of this function + selects `.gnu.linkonce.r.name' if the function's section is + `.gnu.linkonce.t.name', `.rodata.name' if function is in + `.text.name', and the normal readonly-data section otherwise. + + -- Target Hook: section * TARGET_ASM_SELECT_RTX_SECTION (enum + machine_mode MODE, rtx X, unsigned HOST_WIDE_INT ALIGN) + Return the section into which a constant X, of mode MODE, should + be placed. You can assume that X is some kind of constant in RTL. + The argument MODE is redundant except in the case of a `const_int' + rtx. ALIGN is the constant alignment in bits. + + The default version of this function takes care of putting symbolic + constants in `flag_pic' mode in `data_section' and everything else + in `readonly_data_section'. + + -- Target Hook: tree TARGET_MANGLE_DECL_ASSEMBLER_NAME (tree DECL, + tree ID) + Define this hook if you need to postprocess the assembler name + generated by target-independent code. The ID provided to this + hook will be the computed name (e.g., the macro `DECL_NAME' of the + DECL in C, or the mangled name of the DECL in C++). The return + value of the hook is an `IDENTIFIER_NODE' for the appropriate + mangled name on your target system. The default implementation of + this hook just returns the ID provided. + + -- Target Hook: void TARGET_ENCODE_SECTION_INFO (tree DECL, rtx RTL, + int NEW_DECL_P) + Define this hook if references to a symbol or a constant must be + treated differently depending on something about the variable or + function named by the symbol (such as what section it is in). + + The hook is executed immediately after rtl has been created for + DECL, which may be a variable or function declaration or an entry + in the constant pool. In either case, RTL is the rtl in question. + Do _not_ use `DECL_RTL (DECL)' in this hook; that field may not + have been initialized yet. + + In the case of a constant, it is safe to assume that the rtl is a + `mem' whose address is a `symbol_ref'. Most decls will also have + this form, but that is not guaranteed. Global register variables, + for instance, will have a `reg' for their rtl. (Normally the + right thing to do with such unusual rtl is leave it alone.) + + The NEW_DECL_P argument will be true if this is the first time + that `TARGET_ENCODE_SECTION_INFO' has been invoked on this decl. + It will be false for subsequent invocations, which will happen for + duplicate declarations. Whether or not anything must be done for + the duplicate declaration depends on whether the hook examines + `DECL_ATTRIBUTES'. NEW_DECL_P is always true when the hook is + called for a constant. + + The usual thing for this hook to do is to record flags in the + `symbol_ref', using `SYMBOL_REF_FLAG' or `SYMBOL_REF_FLAGS'. + Historically, the name string was modified if it was necessary to + encode more than one bit of information, but this practice is now + discouraged; use `SYMBOL_REF_FLAGS'. + + The default definition of this hook, `default_encode_section_info' + in `varasm.c', sets a number of commonly-useful bits in + `SYMBOL_REF_FLAGS'. Check whether the default does what you need + before overriding it. + + -- Target Hook: const char * TARGET_STRIP_NAME_ENCODING (const char + *NAME) + Decode NAME and return the real name part, sans the characters + that `TARGET_ENCODE_SECTION_INFO' may have added. + + -- Target Hook: bool TARGET_IN_SMALL_DATA_P (const_tree EXP) + Returns true if EXP should be placed into a "small data" section. + The default version of this hook always returns false. + + -- Target Hook: bool TARGET_HAVE_SRODATA_SECTION + Contains the value true if the target places read-only "small + data" into a separate section. The default value is false. + + -- Target Hook: bool TARGET_PROFILE_BEFORE_PROLOGUE (void) + It returns true if target wants profile code emitted before + prologue. + + The default version of this hook use the target macro + `PROFILE_BEFORE_PROLOGUE'. + + -- Target Hook: bool TARGET_BINDS_LOCAL_P (const_tree EXP) + Returns true if EXP names an object for which name resolution + rules must resolve to the current "module" (dynamic shared library + or executable image). + + The default version of this hook implements the name resolution + rules for ELF, which has a looser model of global name binding + than other currently supported object file formats. + + -- Target Hook: bool TARGET_HAVE_TLS + Contains the value true if the target supports thread-local + storage. The default value is false. + + +File: gccint.info, Node: PIC, Next: Assembler Format, Prev: Sections, Up: Target Macros + +17.20 Position Independent Code +=============================== + +This section describes macros that help implement generation of position +independent code. Simply defining these macros is not enough to +generate valid PIC; you must also add support to the hook +`TARGET_LEGITIMATE_ADDRESS_P' and to the macro `PRINT_OPERAND_ADDRESS', +as well as `LEGITIMIZE_ADDRESS'. You must modify the definition of +`movsi' to do something appropriate when the source operand contains a +symbolic address. You may also need to alter the handling of switch +statements so that they use relative addresses. + + -- Macro: PIC_OFFSET_TABLE_REGNUM + The register number of the register used to address a table of + static data addresses in memory. In some cases this register is + defined by a processor's "application binary interface" (ABI). + When this macro is defined, RTL is generated for this register + once, as with the stack pointer and frame pointer registers. If + this macro is not defined, it is up to the machine-dependent files + to allocate such a register (if necessary). Note that this + register must be fixed when in use (e.g. when `flag_pic' is true). + + -- Macro: PIC_OFFSET_TABLE_REG_CALL_CLOBBERED + A C expression that is nonzero if the register defined by + `PIC_OFFSET_TABLE_REGNUM' is clobbered by calls. If not defined, + the default is zero. Do not define this macro if + `PIC_OFFSET_TABLE_REGNUM' is not defined. + + -- Macro: LEGITIMATE_PIC_OPERAND_P (X) + A C expression that is nonzero if X is a legitimate immediate + operand on the target machine when generating position independent + code. You can assume that X satisfies `CONSTANT_P', so you need + not check this. You can also assume FLAG_PIC is true, so you need + not check it either. You need not define this macro if all + constants (including `SYMBOL_REF') can be immediate operands when + generating position independent code. + + +File: gccint.info, Node: Assembler Format, Next: Debugging Info, Prev: PIC, Up: Target Macros + +17.21 Defining the Output Assembler Language +============================================ + +This section describes macros whose principal purpose is to describe how +to write instructions in assembler language--rather than what the +instructions do. + +* Menu: + +* File Framework:: Structural information for the assembler file. +* Data Output:: Output of constants (numbers, strings, addresses). +* Uninitialized Data:: Output of uninitialized variables. +* Label Output:: Output and generation of labels. +* Initialization:: General principles of initialization + and termination routines. +* Macros for Initialization:: + Specific macros that control the handling of + initialization and termination routines. +* Instruction Output:: Output of actual instructions. +* Dispatch Tables:: Output of jump tables. +* Exception Region Output:: Output of exception region code. +* Alignment Output:: Pseudo ops for alignment and skipping data. + + +File: gccint.info, Node: File Framework, Next: Data Output, Up: Assembler Format + +17.21.1 The Overall Framework of an Assembler File +-------------------------------------------------- + +This describes the overall framework of an assembly file. + + -- Target Hook: void TARGET_ASM_FILE_START (void) + Output to `asm_out_file' any text which the assembler expects to + find at the beginning of a file. The default behavior is + controlled by two flags, documented below. Unless your target's + assembler is quite unusual, if you override the default, you + should call `default_file_start' at some point in your target + hook. This lets other target files rely on these variables. + + -- Target Hook: bool TARGET_ASM_FILE_START_APP_OFF + If this flag is true, the text of the macro `ASM_APP_OFF' will be + printed as the very first line in the assembly file, unless + `-fverbose-asm' is in effect. (If that macro has been defined to + the empty string, this variable has no effect.) With the normal + definition of `ASM_APP_OFF', the effect is to notify the GNU + assembler that it need not bother stripping comments or extra + whitespace from its input. This allows it to work a bit faster. + + The default is false. You should not set it to true unless you + have verified that your port does not generate any extra + whitespace or comments that will cause GAS to issue errors in + NO_APP mode. + + -- Target Hook: bool TARGET_ASM_FILE_START_FILE_DIRECTIVE + If this flag is true, `output_file_directive' will be called for + the primary source file, immediately after printing `ASM_APP_OFF' + (if that is enabled). Most ELF assemblers expect this to be done. + The default is false. + + -- Target Hook: void TARGET_ASM_FILE_END (void) + Output to `asm_out_file' any text which the assembler expects to + find at the end of a file. The default is to output nothing. + + -- Function: void file_end_indicate_exec_stack () + Some systems use a common convention, the `.note.GNU-stack' + special section, to indicate whether or not an object file relies + on the stack being executable. If your system uses this + convention, you should define `TARGET_ASM_FILE_END' to this + function. If you need to do other things in that hook, have your + hook function call this function. + + -- Target Hook: void TARGET_ASM_LTO_START (void) + Output to `asm_out_file' any text which the assembler expects to + find at the start of an LTO section. The default is to output + nothing. + + -- Target Hook: void TARGET_ASM_LTO_END (void) + Output to `asm_out_file' any text which the assembler expects to + find at the end of an LTO section. The default is to output + nothing. + + -- Target Hook: void TARGET_ASM_CODE_END (void) + Output to `asm_out_file' any text which is needed before emitting + unwind info and debug info at the end of a file. Some targets emit + here PIC setup thunks that cannot be emitted at the end of file, + because they couldn't have unwind info then. The default is to + output nothing. + + -- Macro: ASM_COMMENT_START + A C string constant describing how to begin a comment in the target + assembler language. The compiler assumes that the comment will + end at the end of the line. + + -- Macro: ASM_APP_ON + A C string constant for text to be output before each `asm' + statement or group of consecutive ones. Normally this is + `"#APP"', which is a comment that has no effect on most assemblers + but tells the GNU assembler that it must check the lines that + follow for all valid assembler constructs. + + -- Macro: ASM_APP_OFF + A C string constant for text to be output after each `asm' + statement or group of consecutive ones. Normally this is + `"#NO_APP"', which tells the GNU assembler to resume making the + time-saving assumptions that are valid for ordinary compiler + output. + + -- Macro: ASM_OUTPUT_SOURCE_FILENAME (STREAM, NAME) + A C statement to output COFF information or DWARF debugging + information which indicates that filename NAME is the current + source file to the stdio stream STREAM. + + This macro need not be defined if the standard form of output for + the file format in use is appropriate. + + -- Target Hook: void TARGET_ASM_OUTPUT_SOURCE_FILENAME (FILE *FILE, + const char *NAME) + Output COFF information or DWARF debugging information which + indicates that filename NAME is the current source file to the + stdio stream FILE. + + This target hook need not be defined if the standard form of + output for the file format in use is appropriate. + + -- Macro: OUTPUT_QUOTED_STRING (STREAM, STRING) + A C statement to output the string STRING to the stdio stream + STREAM. If you do not call the function `output_quoted_string' in + your config files, GCC will only call it to output filenames to + the assembler source. So you can use it to canonicalize the format + of the filename using this macro. + + -- Macro: ASM_OUTPUT_IDENT (STREAM, STRING) + A C statement to output something to the assembler file to handle a + `#ident' directive containing the text STRING. If this macro is + not defined, nothing is output for a `#ident' directive. + + -- Target Hook: void TARGET_ASM_NAMED_SECTION (const char *NAME, + unsigned int FLAGS, tree DECL) + Output assembly directives to switch to section NAME. The section + should have attributes as specified by FLAGS, which is a bit mask + of the `SECTION_*' flags defined in `output.h'. If DECL is + non-NULL, it is the `VAR_DECL' or `FUNCTION_DECL' with which this + section is associated. + + -- Target Hook: section * TARGET_ASM_FUNCTION_SECTION (tree DECL, enum + node_frequency FREQ, bool STARTUP, bool EXIT) + Return preferred text (sub)section for function DECL. Main + purpose of this function is to separate cold, normal and hot + functions. STARTUP is true when function is known to be used only + at startup (from static constructors or it is `main()'). EXIT is + true when function is known to be used only at exit (from static + destructors). Return NULL if function should go to default text + section. + + -- Target Hook: void TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS (FILE + *FILE, tree DECL, bool NEW_IS_COLD) + Used by the target to emit any assembler directives or additional + labels needed when a function is partitioned between different + sections. Output should be written to FILE. The function decl + is available as DECL and the new section is `cold' if NEW_IS_COLD + is `true'. + + -- Target Hook: bool TARGET_HAVE_NAMED_SECTIONS + This flag is true if the target supports + `TARGET_ASM_NAMED_SECTION'. It must not be modified by + command-line option processing. + + -- Target Hook: bool TARGET_HAVE_SWITCHABLE_BSS_SECTIONS + This flag is true if we can create zeroed data by switching to a + BSS section and then using `ASM_OUTPUT_SKIP' to allocate the space. + This is true on most ELF targets. + + -- Target Hook: unsigned int TARGET_SECTION_TYPE_FLAGS (tree DECL, + const char *NAME, int RELOC) + Choose a set of section attributes for use by + `TARGET_ASM_NAMED_SECTION' based on a variable or function decl, a + section name, and whether or not the declaration's initializer may + contain runtime relocations. DECL may be null, in which case + read-write data should be assumed. + + The default version of this function handles choosing code vs data, + read-only vs read-write data, and `flag_pic'. You should only + need to override this if your target has special flags that might + be set via `__attribute__'. + + -- Target Hook: int TARGET_ASM_RECORD_GCC_SWITCHES (print_switch_type + TYPE, const char *TEXT) + Provides the target with the ability to record the gcc command line + switches that have been passed to the compiler, and options that + are enabled. The TYPE argument specifies what is being recorded. + It can take the following values: + + `SWITCH_TYPE_PASSED' + TEXT is a command line switch that has been set by the user. + + `SWITCH_TYPE_ENABLED' + TEXT is an option which has been enabled. This might be as a + direct result of a command line switch, or because it is + enabled by default or because it has been enabled as a side + effect of a different command line switch. For example, the + `-O2' switch enables various different individual + optimization passes. + + `SWITCH_TYPE_DESCRIPTIVE' + TEXT is either NULL or some descriptive text which should be + ignored. If TEXT is NULL then it is being used to warn the + target hook that either recording is starting or ending. The + first time TYPE is SWITCH_TYPE_DESCRIPTIVE and TEXT is NULL, + the warning is for start up and the second time the warning + is for wind down. This feature is to allow the target hook + to make any necessary preparations before it starts to record + switches and to perform any necessary tidying up after it has + finished recording switches. + + `SWITCH_TYPE_LINE_START' + This option can be ignored by this target hook. + + `SWITCH_TYPE_LINE_END' + This option can be ignored by this target hook. + + The hook's return value must be zero. Other return values may be + supported in the future. + + By default this hook is set to NULL, but an example implementation + is provided for ELF based targets. Called ELF_RECORD_GCC_SWITCHES, + it records the switches as ASCII text inside a new, string + mergeable section in the assembler output file. The name of the + new section is provided by the + `TARGET_ASM_RECORD_GCC_SWITCHES_SECTION' target hook. + + -- Target Hook: const char * TARGET_ASM_RECORD_GCC_SWITCHES_SECTION + This is the name of the section that will be created by the example + ELF implementation of the `TARGET_ASM_RECORD_GCC_SWITCHES' target + hook. + + +File: gccint.info, Node: Data Output, Next: Uninitialized Data, Prev: File Framework, Up: Assembler Format + +17.21.2 Output of Data +---------------------- + + -- Target Hook: const char * TARGET_ASM_BYTE_OP + -- Target Hook: const char * TARGET_ASM_ALIGNED_HI_OP + -- Target Hook: const char * TARGET_ASM_ALIGNED_SI_OP + -- Target Hook: const char * TARGET_ASM_ALIGNED_DI_OP + -- Target Hook: const char * TARGET_ASM_ALIGNED_TI_OP + -- Target Hook: const char * TARGET_ASM_UNALIGNED_HI_OP + -- Target Hook: const char * TARGET_ASM_UNALIGNED_SI_OP + -- Target Hook: const char * TARGET_ASM_UNALIGNED_DI_OP + -- Target Hook: const char * TARGET_ASM_UNALIGNED_TI_OP + These hooks specify assembly directives for creating certain kinds + of integer object. The `TARGET_ASM_BYTE_OP' directive creates a + byte-sized object, the `TARGET_ASM_ALIGNED_HI_OP' one creates an + aligned two-byte object, and so on. Any of the hooks may be + `NULL', indicating that no suitable directive is available. + + The compiler will print these strings at the start of a new line, + followed immediately by the object's initial value. In most cases, + the string should contain a tab, a pseudo-op, and then another tab. + + -- Target Hook: bool TARGET_ASM_INTEGER (rtx X, unsigned int SIZE, int + ALIGNED_P) + The `assemble_integer' function uses this hook to output an + integer object. X is the object's value, SIZE is its size in + bytes and ALIGNED_P indicates whether it is aligned. The function + should return `true' if it was able to output the object. If it + returns false, `assemble_integer' will try to split the object + into smaller parts. + + The default implementation of this hook will use the + `TARGET_ASM_BYTE_OP' family of strings, returning `false' when the + relevant string is `NULL'. + + -- Target Hook: bool TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA (FILE *FILE, + rtx X) + A target hook to recognize RTX patterns that `output_addr_const' + can't deal with, and output assembly code to FILE corresponding to + the pattern X. This may be used to allow machine-dependent + `UNSPEC's to appear within constants. + + If target hook fails to recognize a pattern, it must return + `false', so that a standard error message is printed. If it + prints an error message itself, by calling, for example, + `output_operand_lossage', it may just return `true'. + + -- Macro: OUTPUT_ADDR_CONST_EXTRA (STREAM, X, FAIL) + A C statement to recognize RTX patterns that `output_addr_const' + can't deal with, and output assembly code to STREAM corresponding + to the pattern X. This may be used to allow machine-dependent + `UNSPEC's to appear within constants. + + If `OUTPUT_ADDR_CONST_EXTRA' fails to recognize a pattern, it must + `goto fail', so that a standard error message is printed. If it + prints an error message itself, by calling, for example, + `output_operand_lossage', it may just complete normally. + + -- Macro: ASM_OUTPUT_ASCII (STREAM, PTR, LEN) + A C statement to output to the stdio stream STREAM an assembler + instruction to assemble a string constant containing the LEN bytes + at PTR. PTR will be a C expression of type `char *' and LEN a C + expression of type `int'. + + If the assembler has a `.ascii' pseudo-op as found in the Berkeley + Unix assembler, do not define the macro `ASM_OUTPUT_ASCII'. + + -- Macro: ASM_OUTPUT_FDESC (STREAM, DECL, N) + A C statement to output word N of a function descriptor for DECL. + This must be defined if `TARGET_VTABLE_USES_DESCRIPTORS' is + defined, and is otherwise unused. + + -- Macro: CONSTANT_POOL_BEFORE_FUNCTION + You may define this macro as a C expression. You should define the + expression to have a nonzero value if GCC should output the + constant pool for a function before the code for the function, or + a zero value if GCC should output the constant pool after the + function. If you do not define this macro, the usual case, GCC + will output the constant pool before the function. + + -- Macro: ASM_OUTPUT_POOL_PROLOGUE (FILE, FUNNAME, FUNDECL, SIZE) + A C statement to output assembler commands to define the start of + the constant pool for a function. FUNNAME is a string giving the + name of the function. Should the return type of the function be + required, it can be obtained via FUNDECL. SIZE is the size, in + bytes, of the constant pool that will be written immediately after + this call. + + If no constant-pool prefix is required, the usual case, this macro + need not be defined. + + -- Macro: ASM_OUTPUT_SPECIAL_POOL_ENTRY (FILE, X, MODE, ALIGN, + LABELNO, JUMPTO) + A C statement (with or without semicolon) to output a constant in + the constant pool, if it needs special treatment. (This macro + need not do anything for RTL expressions that can be output + normally.) + + The argument FILE is the standard I/O stream to output the + assembler code on. X is the RTL expression for the constant to + output, and MODE is the machine mode (in case X is a `const_int'). + ALIGN is the required alignment for the value X; you should output + an assembler directive to force this much alignment. + + The argument LABELNO is a number to use in an internal label for + the address of this pool entry. The definition of this macro is + responsible for outputting the label definition at the proper + place. Here is how to do this: + + `(*targetm.asm_out.internal_label)' (FILE, "LC", LABELNO); + + When you output a pool entry specially, you should end with a + `goto' to the label JUMPTO. This will prevent the same pool entry + from being output a second time in the usual manner. + + You need not define this macro if it would do nothing. + + -- Macro: ASM_OUTPUT_POOL_EPILOGUE (FILE FUNNAME FUNDECL SIZE) + A C statement to output assembler commands to at the end of the + constant pool for a function. FUNNAME is a string giving the name + of the function. Should the return type of the function be + required, you can obtain it via FUNDECL. SIZE is the size, in + bytes, of the constant pool that GCC wrote immediately before this + call. + + If no constant-pool epilogue is required, the usual case, you need + not define this macro. + + -- Macro: IS_ASM_LOGICAL_LINE_SEPARATOR (C, STR) + Define this macro as a C expression which is nonzero if C is used + as a logical line separator by the assembler. STR points to the + position in the string where C was found; this can be used if a + line separator uses multiple characters. + + If you do not define this macro, the default is that only the + character `;' is treated as a logical line separator. + + -- Target Hook: const char * TARGET_ASM_OPEN_PAREN + -- Target Hook: const char * TARGET_ASM_CLOSE_PAREN + These target hooks are C string constants, describing the syntax + in the assembler for grouping arithmetic expressions. If not + overridden, they default to normal parentheses, which is correct + for most assemblers. + + These macros are provided by `real.h' for writing the definitions of +`ASM_OUTPUT_DOUBLE' and the like: + + -- Macro: REAL_VALUE_TO_TARGET_SINGLE (X, L) + -- Macro: REAL_VALUE_TO_TARGET_DOUBLE (X, L) + -- Macro: REAL_VALUE_TO_TARGET_LONG_DOUBLE (X, L) + -- Macro: REAL_VALUE_TO_TARGET_DECIMAL32 (X, L) + -- Macro: REAL_VALUE_TO_TARGET_DECIMAL64 (X, L) + -- Macro: REAL_VALUE_TO_TARGET_DECIMAL128 (X, L) + These translate X, of type `REAL_VALUE_TYPE', to the target's + floating point representation, and store its bit pattern in the + variable L. For `REAL_VALUE_TO_TARGET_SINGLE' and + `REAL_VALUE_TO_TARGET_DECIMAL32', this variable should be a simple + `long int'. For the others, it should be an array of `long int'. + The number of elements in this array is determined by the size of + the desired target floating point data type: 32 bits of it go in + each `long int' array element. Each array element holds 32 bits + of the result, even if `long int' is wider than 32 bits on the + host machine. + + The array element values are designed so that you can print them + out using `fprintf' in the order they should appear in the target + machine's memory. + + +File: gccint.info, Node: Uninitialized Data, Next: Label Output, Prev: Data Output, Up: Assembler Format + +17.21.3 Output of Uninitialized Variables +----------------------------------------- + +Each of the macros in this section is used to do the whole job of +outputting a single uninitialized variable. + + -- Macro: ASM_OUTPUT_COMMON (STREAM, NAME, SIZE, ROUNDED) + A C statement (sans semicolon) to output to the stdio stream + STREAM the assembler definition of a common-label named NAME whose + size is SIZE bytes. The variable ROUNDED is the size rounded up + to whatever alignment the caller wants. It is possible that SIZE + may be zero, for instance if a struct with no other member than a + zero-length array is defined. In this case, the backend must + output a symbol definition that allocates at least one byte, both + so that the address of the resulting object does not compare equal + to any other, and because some object formats cannot even express + the concept of a zero-sized common symbol, as that is how they + represent an ordinary undefined external. + + Use the expression `assemble_name (STREAM, NAME)' to output the + name itself; before and after that, output the additional + assembler syntax for defining the name, and a newline. + + This macro controls how the assembler definitions of uninitialized + common global variables are output. + + -- Macro: ASM_OUTPUT_ALIGNED_COMMON (STREAM, NAME, SIZE, ALIGNMENT) + Like `ASM_OUTPUT_COMMON' except takes the required alignment as a + separate, explicit argument. If you define this macro, it is used + in place of `ASM_OUTPUT_COMMON', and gives you more flexibility in + handling the required alignment of the variable. The alignment is + specified as the number of bits. + + -- Macro: ASM_OUTPUT_ALIGNED_DECL_COMMON (STREAM, DECL, NAME, SIZE, + ALIGNMENT) + Like `ASM_OUTPUT_ALIGNED_COMMON' except that DECL of the variable + to be output, if there is one, or `NULL_TREE' if there is no + corresponding variable. If you define this macro, GCC will use it + in place of both `ASM_OUTPUT_COMMON' and + `ASM_OUTPUT_ALIGNED_COMMON'. Define this macro when you need to + see the variable's decl in order to chose what to output. + + -- Macro: ASM_OUTPUT_BSS (STREAM, DECL, NAME, SIZE, ROUNDED) + A C statement (sans semicolon) to output to the stdio stream + STREAM the assembler definition of uninitialized global DECL named + NAME whose size is SIZE bytes. The variable ROUNDED is the size + rounded up to whatever alignment the caller wants. + + Try to use function `asm_output_bss' defined in `varasm.c' when + defining this macro. If unable, use the expression `assemble_name + (STREAM, NAME)' to output the name itself; before and after that, + output the additional assembler syntax for defining the name, and + a newline. + + There are two ways of handling global BSS. One is to define either + this macro or its aligned counterpart, `ASM_OUTPUT_ALIGNED_BSS'. + The other is to have `TARGET_ASM_SELECT_SECTION' return a + switchable BSS section (*note + TARGET_HAVE_SWITCHABLE_BSS_SECTIONS::). You do not need to do + both. + + Some languages do not have `common' data, and require a non-common + form of global BSS in order to handle uninitialized globals + efficiently. C++ is one example of this. However, if the target + does not support global BSS, the front end may choose to make + globals common in order to save space in the object file. + + -- Macro: ASM_OUTPUT_ALIGNED_BSS (STREAM, DECL, NAME, SIZE, ALIGNMENT) + Like `ASM_OUTPUT_BSS' except takes the required alignment as a + separate, explicit argument. If you define this macro, it is used + in place of `ASM_OUTPUT_BSS', and gives you more flexibility in + handling the required alignment of the variable. The alignment is + specified as the number of bits. + + Try to use function `asm_output_aligned_bss' defined in file + `varasm.c' when defining this macro. + + -- Macro: ASM_OUTPUT_LOCAL (STREAM, NAME, SIZE, ROUNDED) + A C statement (sans semicolon) to output to the stdio stream + STREAM the assembler definition of a local-common-label named NAME + whose size is SIZE bytes. The variable ROUNDED is the size + rounded up to whatever alignment the caller wants. + + Use the expression `assemble_name (STREAM, NAME)' to output the + name itself; before and after that, output the additional + assembler syntax for defining the name, and a newline. + + This macro controls how the assembler definitions of uninitialized + static variables are output. + + -- Macro: ASM_OUTPUT_ALIGNED_LOCAL (STREAM, NAME, SIZE, ALIGNMENT) + Like `ASM_OUTPUT_LOCAL' except takes the required alignment as a + separate, explicit argument. If you define this macro, it is used + in place of `ASM_OUTPUT_LOCAL', and gives you more flexibility in + handling the required alignment of the variable. The alignment is + specified as the number of bits. + + -- Macro: ASM_OUTPUT_ALIGNED_DECL_LOCAL (STREAM, DECL, NAME, SIZE, + ALIGNMENT) + Like `ASM_OUTPUT_ALIGNED_DECL' except that DECL of the variable to + be output, if there is one, or `NULL_TREE' if there is no + corresponding variable. If you define this macro, GCC will use it + in place of both `ASM_OUTPUT_DECL' and `ASM_OUTPUT_ALIGNED_DECL'. + Define this macro when you need to see the variable's decl in + order to chose what to output. + + +File: gccint.info, Node: Label Output, Next: Initialization, Prev: Uninitialized Data, Up: Assembler Format + +17.21.4 Output and Generation of Labels +--------------------------------------- + +This is about outputting labels. + + -- Macro: ASM_OUTPUT_LABEL (STREAM, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM the assembler definition of a label named NAME. Use the + expression `assemble_name (STREAM, NAME)' to output the name + itself; before and after that, output the additional assembler + syntax for defining the name, and a newline. A default definition + of this macro is provided which is correct for most systems. + + -- Macro: ASM_OUTPUT_FUNCTION_LABEL (STREAM, NAME, DECL) + A C statement (sans semicolon) to output to the stdio stream + STREAM the assembler definition of a label named NAME of a + function. Use the expression `assemble_name (STREAM, NAME)' to + output the name itself; before and after that, output the + additional assembler syntax for defining the name, and a newline. + A default definition of this macro is provided which is correct + for most systems. + + If this macro is not defined, then the function name is defined in + the usual manner as a label (by means of `ASM_OUTPUT_LABEL'). + + -- Macro: ASM_OUTPUT_INTERNAL_LABEL (STREAM, NAME) + Identical to `ASM_OUTPUT_LABEL', except that NAME is known to + refer to a compiler-generated label. The default definition uses + `assemble_name_raw', which is like `assemble_name' except that it + is more efficient. + + -- Macro: SIZE_ASM_OP + A C string containing the appropriate assembler directive to + specify the size of a symbol, without any arguments. On systems + that use ELF, the default (in `config/elfos.h') is `"\t.size\t"'; + on other systems, the default is not to define this macro. + + Define this macro only if it is correct to use the default + definitions of `ASM_OUTPUT_SIZE_DIRECTIVE' and + `ASM_OUTPUT_MEASURED_SIZE' for your system. If you need your own + custom definitions of those macros, or if you do not need explicit + symbol sizes at all, do not define this macro. + + -- Macro: ASM_OUTPUT_SIZE_DIRECTIVE (STREAM, NAME, SIZE) + A C statement (sans semicolon) to output to the stdio stream + STREAM a directive telling the assembler that the size of the + symbol NAME is SIZE. SIZE is a `HOST_WIDE_INT'. If you define + `SIZE_ASM_OP', a default definition of this macro is provided. + + -- Macro: ASM_OUTPUT_MEASURED_SIZE (STREAM, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM a directive telling the assembler to calculate the size of + the symbol NAME by subtracting its address from the current + address. + + If you define `SIZE_ASM_OP', a default definition of this macro is + provided. The default assumes that the assembler recognizes a + special `.' symbol as referring to the current address, and can + calculate the difference between this and another symbol. If your + assembler does not recognize `.' or cannot do calculations with + it, you will need to redefine `ASM_OUTPUT_MEASURED_SIZE' to use + some other technique. + + -- Macro: TYPE_ASM_OP + A C string containing the appropriate assembler directive to + specify the type of a symbol, without any arguments. On systems + that use ELF, the default (in `config/elfos.h') is `"\t.type\t"'; + on other systems, the default is not to define this macro. + + Define this macro only if it is correct to use the default + definition of `ASM_OUTPUT_TYPE_DIRECTIVE' for your system. If you + need your own custom definition of this macro, or if you do not + need explicit symbol types at all, do not define this macro. + + -- Macro: TYPE_OPERAND_FMT + A C string which specifies (using `printf' syntax) the format of + the second operand to `TYPE_ASM_OP'. On systems that use ELF, the + default (in `config/elfos.h') is `"@%s"'; on other systems, the + default is not to define this macro. + + Define this macro only if it is correct to use the default + definition of `ASM_OUTPUT_TYPE_DIRECTIVE' for your system. If you + need your own custom definition of this macro, or if you do not + need explicit symbol types at all, do not define this macro. + + -- Macro: ASM_OUTPUT_TYPE_DIRECTIVE (STREAM, TYPE) + A C statement (sans semicolon) to output to the stdio stream + STREAM a directive telling the assembler that the type of the + symbol NAME is TYPE. TYPE is a C string; currently, that string + is always either `"function"' or `"object"', but you should not + count on this. + + If you define `TYPE_ASM_OP' and `TYPE_OPERAND_FMT', a default + definition of this macro is provided. + + -- Macro: ASM_DECLARE_FUNCTION_NAME (STREAM, NAME, DECL) + A C statement (sans semicolon) to output to the stdio stream + STREAM any text necessary for declaring the name NAME of a + function which is being defined. This macro is responsible for + outputting the label definition (perhaps using + `ASM_OUTPUT_FUNCTION_LABEL'). The argument DECL is the + `FUNCTION_DECL' tree node representing the function. + + If this macro is not defined, then the function name is defined in + the usual manner as a label (by means of + `ASM_OUTPUT_FUNCTION_LABEL'). + + You may wish to use `ASM_OUTPUT_TYPE_DIRECTIVE' in the definition + of this macro. + + -- Macro: ASM_DECLARE_FUNCTION_SIZE (STREAM, NAME, DECL) + A C statement (sans semicolon) to output to the stdio stream + STREAM any text necessary for declaring the size of a function + which is being defined. The argument NAME is the name of the + function. The argument DECL is the `FUNCTION_DECL' tree node + representing the function. + + If this macro is not defined, then the function size is not + defined. + + You may wish to use `ASM_OUTPUT_MEASURED_SIZE' in the definition + of this macro. + + -- Macro: ASM_DECLARE_OBJECT_NAME (STREAM, NAME, DECL) + A C statement (sans semicolon) to output to the stdio stream + STREAM any text necessary for declaring the name NAME of an + initialized variable which is being defined. This macro must + output the label definition (perhaps using `ASM_OUTPUT_LABEL'). + The argument DECL is the `VAR_DECL' tree node representing the + variable. + + If this macro is not defined, then the variable name is defined in + the usual manner as a label (by means of `ASM_OUTPUT_LABEL'). + + You may wish to use `ASM_OUTPUT_TYPE_DIRECTIVE' and/or + `ASM_OUTPUT_SIZE_DIRECTIVE' in the definition of this macro. + + -- Target Hook: void TARGET_ASM_DECLARE_CONSTANT_NAME (FILE *FILE, + const char *NAME, const_tree EXPR, HOST_WIDE_INT SIZE) + A target hook to output to the stdio stream FILE any text necessary + for declaring the name NAME of a constant which is being defined. + This target hook is responsible for outputting the label + definition (perhaps using `assemble_label'). The argument EXP is + the value of the constant, and SIZE is the size of the constant in + bytes. The NAME will be an internal label. + + The default version of this target hook, define the NAME in the + usual manner as a label (by means of `assemble_label'). + + You may wish to use `ASM_OUTPUT_TYPE_DIRECTIVE' in this target + hook. + + -- Macro: ASM_DECLARE_REGISTER_GLOBAL (STREAM, DECL, REGNO, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM any text necessary for claiming a register REGNO for a + global variable DECL with name NAME. + + If you don't define this macro, that is equivalent to defining it + to do nothing. + + -- Macro: ASM_FINISH_DECLARE_OBJECT (STREAM, DECL, TOPLEVEL, ATEND) + A C statement (sans semicolon) to finish up declaring a variable + name once the compiler has processed its initializer fully and + thus has had a chance to determine the size of an array when + controlled by an initializer. This is used on systems where it's + necessary to declare something about the size of the object. + + If you don't define this macro, that is equivalent to defining it + to do nothing. + + You may wish to use `ASM_OUTPUT_SIZE_DIRECTIVE' and/or + `ASM_OUTPUT_MEASURED_SIZE' in the definition of this macro. + + -- Target Hook: void TARGET_ASM_GLOBALIZE_LABEL (FILE *STREAM, const + char *NAME) + This target hook is a function to output to the stdio stream + STREAM some commands that will make the label NAME global; that + is, available for reference from other files. + + The default implementation relies on a proper definition of + `GLOBAL_ASM_OP'. + + -- Target Hook: void TARGET_ASM_GLOBALIZE_DECL_NAME (FILE *STREAM, + tree DECL) + This target hook is a function to output to the stdio stream + STREAM some commands that will make the name associated with DECL + global; that is, available for reference from other files. + + The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL + target hook. + + -- Macro: ASM_WEAKEN_LABEL (STREAM, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM some commands that will make the label NAME weak; that is, + available for reference from other files but only used if no other + definition is available. Use the expression `assemble_name + (STREAM, NAME)' to output the name itself; before and after that, + output the additional assembler syntax for making that name weak, + and a newline. + + If you don't define this macro or `ASM_WEAKEN_DECL', GCC will not + support weak symbols and you should not define the `SUPPORTS_WEAK' + macro. + + -- Macro: ASM_WEAKEN_DECL (STREAM, DECL, NAME, VALUE) + Combines (and replaces) the function of `ASM_WEAKEN_LABEL' and + `ASM_OUTPUT_WEAK_ALIAS', allowing access to the associated function + or variable decl. If VALUE is not `NULL', this C statement should + output to the stdio stream STREAM assembler code which defines + (equates) the weak symbol NAME to have the value VALUE. If VALUE + is `NULL', it should output commands to make NAME weak. + + -- Macro: ASM_OUTPUT_WEAKREF (STREAM, DECL, NAME, VALUE) + Outputs a directive that enables NAME to be used to refer to + symbol VALUE with weak-symbol semantics. `decl' is the + declaration of `name'. + + -- Macro: SUPPORTS_WEAK + A preprocessor constant expression which evaluates to true if the + target supports weak symbols. + + If you don't define this macro, `defaults.h' provides a default + definition. If either `ASM_WEAKEN_LABEL' or `ASM_WEAKEN_DECL' is + defined, the default definition is `1'; otherwise, it is `0'. + + -- Macro: TARGET_SUPPORTS_WEAK + A C expression which evaluates to true if the target supports weak + symbols. + + If you don't define this macro, `defaults.h' provides a default + definition. The default definition is `(SUPPORTS_WEAK)'. Define + this macro if you want to control weak symbol support with a + compiler flag such as `-melf'. + + -- Macro: MAKE_DECL_ONE_ONLY (DECL) + A C statement (sans semicolon) to mark DECL to be emitted as a + public symbol such that extra copies in multiple translation units + will be discarded by the linker. Define this macro if your object + file format provides support for this concept, such as the `COMDAT' + section flags in the Microsoft Windows PE/COFF format, and this + support requires changes to DECL, such as putting it in a separate + section. + + -- Macro: SUPPORTS_ONE_ONLY + A C expression which evaluates to true if the target supports + one-only semantics. + + If you don't define this macro, `varasm.c' provides a default + definition. If `MAKE_DECL_ONE_ONLY' is defined, the default + definition is `1'; otherwise, it is `0'. Define this macro if you + want to control one-only symbol support with a compiler flag, or if + setting the `DECL_ONE_ONLY' flag is enough to mark a declaration to + be emitted as one-only. + + -- Target Hook: void TARGET_ASM_ASSEMBLE_VISIBILITY (tree DECL, int + VISIBILITY) + This target hook is a function to output to ASM_OUT_FILE some + commands that will make the symbol(s) associated with DECL have + hidden, protected or internal visibility as specified by + VISIBILITY. + + -- Macro: TARGET_WEAK_NOT_IN_ARCHIVE_TOC + A C expression that evaluates to true if the target's linker + expects that weak symbols do not appear in a static archive's + table of contents. The default is `0'. + + Leaving weak symbols out of an archive's table of contents means + that, if a symbol will only have a definition in one translation + unit and will have undefined references from other translation + units, that symbol should not be weak. Defining this macro to be + nonzero will thus have the effect that certain symbols that would + normally be weak (explicit template instantiations, and vtables + for polymorphic classes with noninline key methods) will instead + be nonweak. + + The C++ ABI requires this macro to be zero. Define this macro for + targets where full C++ ABI compliance is impossible and where + linker restrictions require weak symbols to be left out of a + static archive's table of contents. + + -- Macro: ASM_OUTPUT_EXTERNAL (STREAM, DECL, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM any text necessary for declaring the name of an external + symbol named NAME which is referenced in this compilation but not + defined. The value of DECL is the tree node for the declaration. + + This macro need not be defined if it does not need to output + anything. The GNU assembler and most Unix assemblers don't + require anything. + + -- Target Hook: void TARGET_ASM_EXTERNAL_LIBCALL (rtx SYMREF) + This target hook is a function to output to ASM_OUT_FILE an + assembler pseudo-op to declare a library function name external. + The name of the library function is given by SYMREF, which is a + `symbol_ref'. + + -- Target Hook: void TARGET_ASM_MARK_DECL_PRESERVED (const char + *SYMBOL) + This target hook is a function to output to ASM_OUT_FILE an + assembler directive to annotate SYMBOL as used. The Darwin target + uses the .no_dead_code_strip directive. + + -- Macro: ASM_OUTPUT_LABELREF (STREAM, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM a reference in assembler syntax to a label named NAME. + This should add `_' to the front of the name, if that is customary + on your operating system, as it is in most Berkeley Unix systems. + This macro is used in `assemble_name'. + + -- Target Hook: tree TARGET_MANGLE_ASSEMBLER_NAME (const char *NAME) + Given a symbol NAME, perform same mangling as `varasm.c''s + `assemble_name', but in memory rather than to a file stream, + returning result as an `IDENTIFIER_NODE'. Required for correct + LTO symtabs. The default implementation calls the + `TARGET_STRIP_NAME_ENCODING' hook and then prepends the + `USER_LABEL_PREFIX', if any. + + -- Macro: ASM_OUTPUT_SYMBOL_REF (STREAM, SYM) + A C statement (sans semicolon) to output a reference to + `SYMBOL_REF' SYM. If not defined, `assemble_name' will be used to + output the name of the symbol. This macro may be used to modify + the way a symbol is referenced depending on information encoded by + `TARGET_ENCODE_SECTION_INFO'. + + -- Macro: ASM_OUTPUT_LABEL_REF (STREAM, BUF) + A C statement (sans semicolon) to output a reference to BUF, the + result of `ASM_GENERATE_INTERNAL_LABEL'. If not defined, + `assemble_name' will be used to output the name of the symbol. + This macro is not used by `output_asm_label', or the `%l' + specifier that calls it; the intention is that this macro should + be set when it is necessary to output a label differently when its + address is being taken. + + -- Target Hook: void TARGET_ASM_INTERNAL_LABEL (FILE *STREAM, const + char *PREFIX, unsigned long LABELNO) + A function to output to the stdio stream STREAM a label whose name + is made from the string PREFIX and the number LABELNO. + + It is absolutely essential that these labels be distinct from the + labels used for user-level functions and variables. Otherwise, + certain programs will have name conflicts with internal labels. + + It is desirable to exclude internal labels from the symbol table + of the object file. Most assemblers have a naming convention for + labels that should be excluded; on many systems, the letter `L' at + the beginning of a label has this effect. You should find out what + convention your system uses, and follow it. + + The default version of this function utilizes + `ASM_GENERATE_INTERNAL_LABEL'. + + -- Macro: ASM_OUTPUT_DEBUG_LABEL (STREAM, PREFIX, NUM) + A C statement to output to the stdio stream STREAM a debug info + label whose name is made from the string PREFIX and the number + NUM. This is useful for VLIW targets, where debug info labels may + need to be treated differently than branch target labels. On some + systems, branch target labels must be at the beginning of + instruction bundles, but debug info labels can occur in the middle + of instruction bundles. + + If this macro is not defined, then + `(*targetm.asm_out.internal_label)' will be used. + + -- Macro: ASM_GENERATE_INTERNAL_LABEL (STRING, PREFIX, NUM) + A C statement to store into the string STRING a label whose name + is made from the string PREFIX and the number NUM. + + This string, when output subsequently by `assemble_name', should + produce the output that `(*targetm.asm_out.internal_label)' would + produce with the same PREFIX and NUM. + + If the string begins with `*', then `assemble_name' will output + the rest of the string unchanged. It is often convenient for + `ASM_GENERATE_INTERNAL_LABEL' to use `*' in this way. If the + string doesn't start with `*', then `ASM_OUTPUT_LABELREF' gets to + output the string, and may change it. (Of course, + `ASM_OUTPUT_LABELREF' is also part of your machine description, so + you should know what it does on your machine.) + + -- Macro: ASM_FORMAT_PRIVATE_NAME (OUTVAR, NAME, NUMBER) + A C expression to assign to OUTVAR (which is a variable of type + `char *') a newly allocated string made from the string NAME and + the number NUMBER, with some suitable punctuation added. Use + `alloca' to get space for the string. + + The string will be used as an argument to `ASM_OUTPUT_LABELREF' to + produce an assembler label for an internal static variable whose + name is NAME. Therefore, the string must be such as to result in + valid assembler code. The argument NUMBER is different each time + this macro is executed; it prevents conflicts between + similarly-named internal static variables in different scopes. + + Ideally this string should not be a valid C identifier, to prevent + any conflict with the user's own symbols. Most assemblers allow + periods or percent signs in assembler symbols; putting at least + one of these between the name and the number will suffice. + + If this macro is not defined, a default definition will be provided + which is correct for most systems. + + -- Macro: ASM_OUTPUT_DEF (STREAM, NAME, VALUE) + A C statement to output to the stdio stream STREAM assembler code + which defines (equates) the symbol NAME to have the value VALUE. + + If `SET_ASM_OP' is defined, a default definition is provided which + is correct for most systems. + + -- Macro: ASM_OUTPUT_DEF_FROM_DECLS (STREAM, DECL_OF_NAME, + DECL_OF_VALUE) + A C statement to output to the stdio stream STREAM assembler code + which defines (equates) the symbol whose tree node is DECL_OF_NAME + to have the value of the tree node DECL_OF_VALUE. This macro will + be used in preference to `ASM_OUTPUT_DEF' if it is defined and if + the tree nodes are available. + + If `SET_ASM_OP' is defined, a default definition is provided which + is correct for most systems. + + -- Macro: TARGET_DEFERRED_OUTPUT_DEFS (DECL_OF_NAME, DECL_OF_VALUE) + A C statement that evaluates to true if the assembler code which + defines (equates) the symbol whose tree node is DECL_OF_NAME to + have the value of the tree node DECL_OF_VALUE should be emitted + near the end of the current compilation unit. The default is to + not defer output of defines. This macro affects defines output by + `ASM_OUTPUT_DEF' and `ASM_OUTPUT_DEF_FROM_DECLS'. + + -- Macro: ASM_OUTPUT_WEAK_ALIAS (STREAM, NAME, VALUE) + A C statement to output to the stdio stream STREAM assembler code + which defines (equates) the weak symbol NAME to have the value + VALUE. If VALUE is `NULL', it defines NAME as an undefined weak + symbol. + + Define this macro if the target only supports weak aliases; define + `ASM_OUTPUT_DEF' instead if possible. + + -- Macro: OBJC_GEN_METHOD_LABEL (BUF, IS_INST, CLASS_NAME, CAT_NAME, + SEL_NAME) + Define this macro to override the default assembler names used for + Objective-C methods. + + The default name is a unique method number followed by the name of + the class (e.g. `_1_Foo'). For methods in categories, the name of + the category is also included in the assembler name (e.g. + `_1_Foo_Bar'). + + These names are safe on most systems, but make debugging difficult + since the method's selector is not present in the name. + Therefore, particular systems define other ways of computing names. + + BUF is an expression of type `char *' which gives you a buffer in + which to store the name; its length is as long as CLASS_NAME, + CAT_NAME and SEL_NAME put together, plus 50 characters extra. + + The argument IS_INST specifies whether the method is an instance + method or a class method; CLASS_NAME is the name of the class; + CAT_NAME is the name of the category (or `NULL' if the method is + not in a category); and SEL_NAME is the name of the selector. + + On systems where the assembler can handle quoted names, you can + use this macro to provide more human-readable names. + + -- Macro: ASM_DECLARE_CLASS_REFERENCE (STREAM, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM commands to declare that the label NAME is an Objective-C + class reference. This is only needed for targets whose linkers + have special support for NeXT-style runtimes. + + -- Macro: ASM_DECLARE_UNRESOLVED_REFERENCE (STREAM, NAME) + A C statement (sans semicolon) to output to the stdio stream + STREAM commands to declare that the label NAME is an unresolved + Objective-C class reference. This is only needed for targets + whose linkers have special support for NeXT-style runtimes. + + +File: gccint.info, Node: Initialization, Next: Macros for Initialization, Prev: Label Output, Up: Assembler Format + +17.21.5 How Initialization Functions Are Handled +------------------------------------------------ + +The compiled code for certain languages includes "constructors" (also +called "initialization routines")--functions to initialize data in the +program when the program is started. These functions need to be called +before the program is "started"--that is to say, before `main' is +called. + + Compiling some languages generates "destructors" (also called +"termination routines") that should be called when the program +terminates. + + To make the initialization and termination functions work, the compiler +must output something in the assembler code to cause those functions to +be called at the appropriate time. When you port the compiler to a new +system, you need to specify how to do this. + + There are two major ways that GCC currently supports the execution of +initialization and termination functions. Each way has two variants. +Much of the structure is common to all four variations. + + The linker must build two lists of these functions--a list of +initialization functions, called `__CTOR_LIST__', and a list of +termination functions, called `__DTOR_LIST__'. + + Each list always begins with an ignored function pointer (which may +hold 0, -1, or a count of the function pointers after it, depending on +the environment). This is followed by a series of zero or more function +pointers to constructors (or destructors), followed by a function +pointer containing zero. + + Depending on the operating system and its executable file format, +either `crtstuff.c' or `libgcc2.c' traverses these lists at startup +time and exit time. Constructors are called in reverse order of the +list; destructors in forward order. + + The best way to handle static constructors works only for object file +formats which provide arbitrarily-named sections. A section is set +aside for a list of constructors, and another for a list of destructors. +Traditionally these are called `.ctors' and `.dtors'. Each object file +that defines an initialization function also puts a word in the +constructor section to point to that function. The linker accumulates +all these words into one contiguous `.ctors' section. Termination +functions are handled similarly. + + This method will be chosen as the default by `target-def.h' if +`TARGET_ASM_NAMED_SECTION' is defined. A target that does not support +arbitrary sections, but does support special designated constructor and +destructor sections may define `CTORS_SECTION_ASM_OP' and +`DTORS_SECTION_ASM_OP' to achieve the same effect. + + When arbitrary sections are available, there are two variants, +depending upon how the code in `crtstuff.c' is called. On systems that +support a ".init" section which is executed at program startup, parts +of `crtstuff.c' are compiled into that section. The program is linked +by the `gcc' driver like this: + + ld -o OUTPUT_FILE crti.o crtbegin.o ... -lgcc crtend.o crtn.o + + The prologue of a function (`__init') appears in the `.init' section +of `crti.o'; the epilogue appears in `crtn.o'. Likewise for the +function `__fini' in the ".fini" section. Normally these files are +provided by the operating system or by the GNU C library, but are +provided by GCC for a few targets. + + The objects `crtbegin.o' and `crtend.o' are (for most targets) +compiled from `crtstuff.c'. They contain, among other things, code +fragments within the `.init' and `.fini' sections that branch to +routines in the `.text' section. The linker will pull all parts of a +section together, which results in a complete `__init' function that +invokes the routines we need at startup. + + To use this variant, you must define the `INIT_SECTION_ASM_OP' macro +properly. + + If no init section is available, when GCC compiles any function called +`main' (or more accurately, any function designated as a program entry +point by the language front end calling `expand_main_function'), it +inserts a procedure call to `__main' as the first executable code after +the function prologue. The `__main' function is defined in `libgcc2.c' +and runs the global constructors. + + In file formats that don't support arbitrary sections, there are again +two variants. In the simplest variant, the GNU linker (GNU `ld') and +an `a.out' format must be used. In this case, `TARGET_ASM_CONSTRUCTOR' +is defined to produce a `.stabs' entry of type `N_SETT', referencing +the name `__CTOR_LIST__', and with the address of the void function +containing the initialization code as its value. The GNU linker +recognizes this as a request to add the value to a "set"; the values +are accumulated, and are eventually placed in the executable as a +vector in the format described above, with a leading (ignored) count +and a trailing zero element. `TARGET_ASM_DESTRUCTOR' is handled +similarly. Since no init section is available, the absence of +`INIT_SECTION_ASM_OP' causes the compilation of `main' to call `__main' +as above, starting the initialization process. + + The last variant uses neither arbitrary sections nor the GNU linker. +This is preferable when you want to do dynamic linking and when using +file formats which the GNU linker does not support, such as `ECOFF'. In +this case, `TARGET_HAVE_CTORS_DTORS' is false, initialization and +termination functions are recognized simply by their names. This +requires an extra program in the linkage step, called `collect2'. This +program pretends to be the linker, for use with GCC; it does its job by +running the ordinary linker, but also arranges to include the vectors of +initialization and termination functions. These functions are called +via `__main' as described above. In order to use this method, +`use_collect2' must be defined in the target in `config.gcc'. + + The following section describes the specific macros that control and +customize the handling of initialization and termination functions. + + +File: gccint.info, Node: Macros for Initialization, Next: Instruction Output, Prev: Initialization, Up: Assembler Format + +17.21.6 Macros Controlling Initialization Routines +-------------------------------------------------- + +Here are the macros that control how the compiler handles initialization +and termination functions: + + -- Macro: INIT_SECTION_ASM_OP + If defined, a C string constant, including spacing, for the + assembler operation to identify the following data as + initialization code. If not defined, GCC will assume such a + section does not exist. When you are using special sections for + initialization and termination functions, this macro also controls + how `crtstuff.c' and `libgcc2.c' arrange to run the initialization + functions. + + -- Macro: HAS_INIT_SECTION + If defined, `main' will not call `__main' as described above. + This macro should be defined for systems that control start-up code + on a symbol-by-symbol basis, such as OSF/1, and should not be + defined explicitly for systems that support `INIT_SECTION_ASM_OP'. + + -- Macro: LD_INIT_SWITCH + If defined, a C string constant for a switch that tells the linker + that the following symbol is an initialization routine. + + -- Macro: LD_FINI_SWITCH + If defined, a C string constant for a switch that tells the linker + that the following symbol is a finalization routine. + + -- Macro: COLLECT_SHARED_INIT_FUNC (STREAM, FUNC) + If defined, a C statement that will write a function that can be + automatically called when a shared library is loaded. The function + should call FUNC, which takes no arguments. If not defined, and + the object format requires an explicit initialization function, + then a function called `_GLOBAL__DI' will be generated. + + This function and the following one are used by collect2 when + linking a shared library that needs constructors or destructors, + or has DWARF2 exception tables embedded in the code. + + -- Macro: COLLECT_SHARED_FINI_FUNC (STREAM, FUNC) + If defined, a C statement that will write a function that can be + automatically called when a shared library is unloaded. The + function should call FUNC, which takes no arguments. If not + defined, and the object format requires an explicit finalization + function, then a function called `_GLOBAL__DD' will be generated. + + -- Macro: INVOKE__main + If defined, `main' will call `__main' despite the presence of + `INIT_SECTION_ASM_OP'. This macro should be defined for systems + where the init section is not actually run automatically, but is + still useful for collecting the lists of constructors and + destructors. + + -- Macro: SUPPORTS_INIT_PRIORITY + If nonzero, the C++ `init_priority' attribute is supported and the + compiler should emit instructions to control the order of + initialization of objects. If zero, the compiler will issue an + error message upon encountering an `init_priority' attribute. + + -- Target Hook: bool TARGET_HAVE_CTORS_DTORS + This value is true if the target supports some "native" method of + collecting constructors and destructors to be run at startup and + exit. It is false if we must use `collect2'. + + -- Target Hook: void TARGET_ASM_CONSTRUCTOR (rtx SYMBOL, int PRIORITY) + If defined, a function that outputs assembler code to arrange to + call the function referenced by SYMBOL at initialization time. + + Assume that SYMBOL is a `SYMBOL_REF' for a function taking no + arguments and with no return value. If the target supports + initialization priorities, PRIORITY is a value between 0 and + `MAX_INIT_PRIORITY'; otherwise it must be `DEFAULT_INIT_PRIORITY'. + + If this macro is not defined by the target, a suitable default will + be chosen if (1) the target supports arbitrary section names, (2) + the target defines `CTORS_SECTION_ASM_OP', or (3) `USE_COLLECT2' + is not defined. + + -- Target Hook: void TARGET_ASM_DESTRUCTOR (rtx SYMBOL, int PRIORITY) + This is like `TARGET_ASM_CONSTRUCTOR' but used for termination + functions rather than initialization functions. + + If `TARGET_HAVE_CTORS_DTORS' is true, the initialization routine +generated for the generated object file will have static linkage. + + If your system uses `collect2' as the means of processing +constructors, then that program normally uses `nm' to scan an object +file for constructor functions to be called. + + On certain kinds of systems, you can define this macro to make +`collect2' work faster (and, in some cases, make it work at all): + + -- Macro: OBJECT_FORMAT_COFF + Define this macro if the system uses COFF (Common Object File + Format) object files, so that `collect2' can assume this format + and scan object files directly for dynamic constructor/destructor + functions. + + This macro is effective only in a native compiler; `collect2' as + part of a cross compiler always uses `nm' for the target machine. + + -- Macro: REAL_NM_FILE_NAME + Define this macro as a C string constant containing the file name + to use to execute `nm'. The default is to search the path + normally for `nm'. + + -- Macro: NM_FLAGS + `collect2' calls `nm' to scan object files for static constructors + and destructors and LTO info. By default, `-n' is passed. Define + `NM_FLAGS' to a C string constant if other options are needed to + get the same output format as GNU `nm -n' produces. + + If your system supports shared libraries and has a program to list the +dynamic dependencies of a given library or executable, you can define +these macros to enable support for running initialization and +termination functions in shared libraries: + + -- Macro: LDD_SUFFIX + Define this macro to a C string constant containing the name of + the program which lists dynamic dependencies, like `ldd' under + SunOS 4. + + -- Macro: PARSE_LDD_OUTPUT (PTR) + Define this macro to be C code that extracts filenames from the + output of the program denoted by `LDD_SUFFIX'. PTR is a variable + of type `char *' that points to the beginning of a line of output + from `LDD_SUFFIX'. If the line lists a dynamic dependency, the + code must advance PTR to the beginning of the filename on that + line. Otherwise, it must set PTR to `NULL'. + + -- Macro: SHLIB_SUFFIX + Define this macro to a C string constant containing the default + shared library extension of the target (e.g., `".so"'). `collect2' + strips version information after this suffix when generating global + constructor and destructor names. This define is only needed on + targets that use `collect2' to process constructors and + destructors. + + +File: gccint.info, Node: Instruction Output, Next: Dispatch Tables, Prev: Macros for Initialization, Up: Assembler Format + +17.21.7 Output of Assembler Instructions +---------------------------------------- + +This describes assembler instruction output. + + -- Macro: REGISTER_NAMES + A C initializer containing the assembler's names for the machine + registers, each one as a C string constant. This is what + translates register numbers in the compiler into assembler + language. + + -- Macro: ADDITIONAL_REGISTER_NAMES + If defined, a C initializer for an array of structures containing + a name and a register number. This macro defines additional names + for hard registers, thus allowing the `asm' option in declarations + to refer to registers using alternate names. + + -- Macro: OVERLAPPING_REGISTER_NAMES + If defined, a C initializer for an array of structures containing a + name, a register number and a count of the number of consecutive + machine registers the name overlaps. This macro defines additional + names for hard registers, thus allowing the `asm' option in + declarations to refer to registers using alternate names. Unlike + `ADDITIONAL_REGISTER_NAMES', this macro should be used when the + register name implies multiple underlying registers. + + This macro should be used when it is important that a clobber in an + `asm' statement clobbers all the underlying values implied by the + register name. For example, on ARM, clobbering the + double-precision VFP register "d0" implies clobbering both + single-precision registers "s0" and "s1". + + -- Macro: ASM_OUTPUT_OPCODE (STREAM, PTR) + Define this macro if you are using an unusual assembler that + requires different names for the machine instructions. + + The definition is a C statement or statements which output an + assembler instruction opcode to the stdio stream STREAM. The + macro-operand PTR is a variable of type `char *' which points to + the opcode name in its "internal" form--the form that is written + in the machine description. The definition should output the + opcode name to STREAM, performing any translation you desire, and + increment the variable PTR to point at the end of the opcode so + that it will not be output twice. + + In fact, your macro definition may process less than the entire + opcode name, or more than the opcode name; but if you want to + process text that includes `%'-sequences to substitute operands, + you must take care of the substitution yourself. Just be sure to + increment PTR over whatever text should not be output normally. + + If you need to look at the operand values, they can be found as the + elements of `recog_data.operand'. + + If the macro definition does nothing, the instruction is output in + the usual way. + + -- Macro: FINAL_PRESCAN_INSN (INSN, OPVEC, NOPERANDS) + If defined, a C statement to be executed just prior to the output + of assembler code for INSN, to modify the extracted operands so + they will be output differently. + + Here the argument OPVEC is the vector containing the operands + extracted from INSN, and NOPERANDS is the number of elements of + the vector which contain meaningful data for this insn. The + contents of this vector are what will be used to convert the insn + template into assembler code, so you can change the assembler + output by changing the contents of the vector. + + This macro is useful when various assembler syntaxes share a single + file of instruction patterns; by defining this macro differently, + you can cause a large class of instructions to be output + differently (such as with rearranged operands). Naturally, + variations in assembler syntax affecting individual insn patterns + ought to be handled by writing conditional output routines in + those patterns. + + If this macro is not defined, it is equivalent to a null statement. + + -- Target Hook: void TARGET_ASM_FINAL_POSTSCAN_INSN (FILE *FILE, rtx + INSN, rtx *OPVEC, int NOPERANDS) + If defined, this target hook is a function which is executed just + after the output of assembler code for INSN, to change the mode of + the assembler if necessary. + + Here the argument OPVEC is the vector containing the operands + extracted from INSN, and NOPERANDS is the number of elements of + the vector which contain meaningful data for this insn. The + contents of this vector are what was used to convert the insn + template into assembler code, so you can change the assembler mode + by checking the contents of the vector. + + -- Macro: PRINT_OPERAND (STREAM, X, CODE) + A C compound statement to output to stdio stream STREAM the + assembler syntax for an instruction operand X. X is an RTL + expression. + + CODE is a value that can be used to specify one of several ways of + printing the operand. It is used when identical operands must be + printed differently depending on the context. CODE comes from the + `%' specification that was used to request printing of the + operand. If the specification was just `%DIGIT' then CODE is 0; + if the specification was `%LTR DIGIT' then CODE is the ASCII code + for LTR. + + If X is a register, this macro should print the register's name. + The names can be found in an array `reg_names' whose type is `char + *[]'. `reg_names' is initialized from `REGISTER_NAMES'. + + When the machine description has a specification `%PUNCT' (a `%' + followed by a punctuation character), this macro is called with a + null pointer for X and the punctuation character for CODE. + + -- Macro: PRINT_OPERAND_PUNCT_VALID_P (CODE) + A C expression which evaluates to true if CODE is a valid + punctuation character for use in the `PRINT_OPERAND' macro. If + `PRINT_OPERAND_PUNCT_VALID_P' is not defined, it means that no + punctuation characters (except for the standard one, `%') are used + in this way. + + -- Macro: PRINT_OPERAND_ADDRESS (STREAM, X) + A C compound statement to output to stdio stream STREAM the + assembler syntax for an instruction operand that is a memory + reference whose address is X. X is an RTL expression. + + On some machines, the syntax for a symbolic address depends on the + section that the address refers to. On these machines, define the + hook `TARGET_ENCODE_SECTION_INFO' to store the information into the + `symbol_ref', and then check for it here. *Note Assembler + Format::. + + -- Macro: DBR_OUTPUT_SEQEND (FILE) + A C statement, to be executed after all slot-filler instructions + have been output. If necessary, call `dbr_sequence_length' to + determine the number of slots filled in a sequence (zero if not + currently outputting a sequence), to decide how many no-ops to + output, or whatever. + + Don't define this macro if it has nothing to do, but it is helpful + in reading assembly output if the extent of the delay sequence is + made explicit (e.g. with white space). + + Note that output routines for instructions with delay slots must be +prepared to deal with not being output as part of a sequence (i.e. when +the scheduling pass is not run, or when no slot fillers could be +found.) The variable `final_sequence' is null when not processing a +sequence, otherwise it contains the `sequence' rtx being output. + + -- Macro: REGISTER_PREFIX + -- Macro: LOCAL_LABEL_PREFIX + -- Macro: USER_LABEL_PREFIX + -- Macro: IMMEDIATE_PREFIX + If defined, C string expressions to be used for the `%R', `%L', + `%U', and `%I' options of `asm_fprintf' (see `final.c'). These + are useful when a single `md' file must support multiple assembler + formats. In that case, the various `tm.h' files can define these + macros differently. + + -- Macro: ASM_FPRINTF_EXTENSIONS (FILE, ARGPTR, FORMAT) + If defined this macro should expand to a series of `case' + statements which will be parsed inside the `switch' statement of + the `asm_fprintf' function. This allows targets to define extra + printf formats which may useful when generating their assembler + statements. Note that uppercase letters are reserved for future + generic extensions to asm_fprintf, and so are not available to + target specific code. The output file is given by the parameter + FILE. The varargs input pointer is ARGPTR and the rest of the + format string, starting the character after the one that is being + switched upon, is pointed to by FORMAT. + + -- Macro: ASSEMBLER_DIALECT + If your target supports multiple dialects of assembler language + (such as different opcodes), define this macro as a C expression + that gives the numeric index of the assembler language dialect to + use, with zero as the first variant. + + If this macro is defined, you may use constructs of the form + `{option0|option1|option2...}' + in the output templates of patterns (*note Output Template::) or + in the first argument of `asm_fprintf'. This construct outputs + `option0', `option1', `option2', etc., if the value of + `ASSEMBLER_DIALECT' is zero, one, two, etc. Any special characters + within these strings retain their usual meaning. If there are + fewer alternatives within the braces than the value of + `ASSEMBLER_DIALECT', the construct outputs nothing. + + If you do not define this macro, the characters `{', `|' and `}' + do not have any special meaning when used in templates or operands + to `asm_fprintf'. + + Define the macros `REGISTER_PREFIX', `LOCAL_LABEL_PREFIX', + `USER_LABEL_PREFIX' and `IMMEDIATE_PREFIX' if you can express the + variations in assembler language syntax with that mechanism. + Define `ASSEMBLER_DIALECT' and use the `{option0|option1}' syntax + if the syntax variant are larger and involve such things as + different opcodes or operand order. + + -- Macro: ASM_OUTPUT_REG_PUSH (STREAM, REGNO) + A C expression to output to STREAM some assembler code which will + push hard register number REGNO onto the stack. The code need not + be optimal, since this macro is used only when profiling. + + -- Macro: ASM_OUTPUT_REG_POP (STREAM, REGNO) + A C expression to output to STREAM some assembler code which will + pop hard register number REGNO off of the stack. The code need + not be optimal, since this macro is used only when profiling. + + +File: gccint.info, Node: Dispatch Tables, Next: Exception Region Output, Prev: Instruction Output, Up: Assembler Format + +17.21.8 Output of Dispatch Tables +--------------------------------- + +This concerns dispatch tables. + + -- Macro: ASM_OUTPUT_ADDR_DIFF_ELT (STREAM, BODY, VALUE, REL) + A C statement to output to the stdio stream STREAM an assembler + pseudo-instruction to generate a difference between two labels. + VALUE and REL are the numbers of two internal labels. The + definitions of these labels are output using + `(*targetm.asm_out.internal_label)', and they must be printed in + the same way here. For example, + + fprintf (STREAM, "\t.word L%d-L%d\n", + VALUE, REL) + + You must provide this macro on machines where the addresses in a + dispatch table are relative to the table's own address. If + defined, GCC will also use this macro on all machines when + producing PIC. BODY is the body of the `ADDR_DIFF_VEC'; it is + provided so that the mode and flags can be read. + + -- Macro: ASM_OUTPUT_ADDR_VEC_ELT (STREAM, VALUE) + This macro should be provided on machines where the addresses in a + dispatch table are absolute. + + The definition should be a C statement to output to the stdio + stream STREAM an assembler pseudo-instruction to generate a + reference to a label. VALUE is the number of an internal label + whose definition is output using + `(*targetm.asm_out.internal_label)'. For example, + + fprintf (STREAM, "\t.word L%d\n", VALUE) + + -- Macro: ASM_OUTPUT_CASE_LABEL (STREAM, PREFIX, NUM, TABLE) + Define this if the label before a jump-table needs to be output + specially. The first three arguments are the same as for + `(*targetm.asm_out.internal_label)'; the fourth argument is the + jump-table which follows (a `jump_insn' containing an `addr_vec' + or `addr_diff_vec'). + + This feature is used on system V to output a `swbeg' statement for + the table. + + If this macro is not defined, these labels are output with + `(*targetm.asm_out.internal_label)'. + + -- Macro: ASM_OUTPUT_CASE_END (STREAM, NUM, TABLE) + Define this if something special must be output at the end of a + jump-table. The definition should be a C statement to be executed + after the assembler code for the table is written. It should write + the appropriate code to stdio stream STREAM. The argument TABLE + is the jump-table insn, and NUM is the label-number of the + preceding label. + + If this macro is not defined, nothing special is output at the end + of the jump-table. + + -- Target Hook: void TARGET_ASM_EMIT_UNWIND_LABEL (FILE *STREAM, tree + DECL, int FOR_EH, int EMPTY) + This target hook emits a label at the beginning of each FDE. It + should be defined on targets where FDEs need special labels, and it + should write the appropriate label, for the FDE associated with the + function declaration DECL, to the stdio stream STREAM. The third + argument, FOR_EH, is a boolean: true if this is for an exception + table. The fourth argument, EMPTY, is a boolean: true if this is + a placeholder label for an omitted FDE. + + The default is that FDEs are not given nonlocal labels. + + -- Target Hook: void TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL (FILE *STREAM) + This target hook emits a label at the beginning of the exception + table. It should be defined on targets where it is desirable for + the table to be broken up according to function. + + The default is that no label is emitted. + + -- Target Hook: void TARGET_ASM_EMIT_EXCEPT_PERSONALITY (rtx + PERSONALITY) + If the target implements `TARGET_ASM_UNWIND_EMIT', this hook may + be used to emit a directive to install a personality hook into the + unwind info. This hook should not be used if dwarf2 unwind info + is used. + + -- Target Hook: void TARGET_ASM_UNWIND_EMIT (FILE *STREAM, rtx INSN) + This target hook emits assembly directives required to unwind the + given instruction. This is only used when + `TARGET_EXCEPT_UNWIND_INFO' returns `UI_TARGET'. + + -- Target Hook: bool TARGET_ASM_UNWIND_EMIT_BEFORE_INSN + True if the `TARGET_ASM_UNWIND_EMIT' hook should be called before + the assembly for INSN has been emitted, false if the hook should + be called afterward. + + +File: gccint.info, Node: Exception Region Output, Next: Alignment Output, Prev: Dispatch Tables, Up: Assembler Format + +17.21.9 Assembler Commands for Exception Regions +------------------------------------------------ + +This describes commands marking the start and the end of an exception +region. + + -- Macro: EH_FRAME_SECTION_NAME + If defined, a C string constant for the name of the section + containing exception handling frame unwind information. If not + defined, GCC will provide a default definition if the target + supports named sections. `crtstuff.c' uses this macro to switch + to the appropriate section. + + You should define this symbol if your target supports DWARF 2 frame + unwind information and the default definition does not work. + + -- Macro: EH_FRAME_IN_DATA_SECTION + If defined, DWARF 2 frame unwind information will be placed in the + data section even though the target supports named sections. This + might be necessary, for instance, if the system linker does garbage + collection and sections cannot be marked as not to be collected. + + Do not define this macro unless `TARGET_ASM_NAMED_SECTION' is also + defined. + + -- Macro: EH_TABLES_CAN_BE_READ_ONLY + Define this macro to 1 if your target is such that no frame unwind + information encoding used with non-PIC code will ever require a + runtime relocation, but the linker may not support merging + read-only and read-write sections into a single read-write section. + + -- Macro: MASK_RETURN_ADDR + An rtx used to mask the return address found via + `RETURN_ADDR_RTX', so that it does not contain any extraneous set + bits in it. + + -- Macro: DWARF2_UNWIND_INFO + Define this macro to 0 if your target supports DWARF 2 frame unwind + information, but it does not yet work with exception handling. + Otherwise, if your target supports this information (if it defines + `INCOMING_RETURN_ADDR_RTX' and either `UNALIGNED_INT_ASM_OP' or + `OBJECT_FORMAT_ELF'), GCC will provide a default definition of 1. + + -- Target Hook: enum unwind_info_type TARGET_EXCEPT_UNWIND_INFO + (struct gcc_options *OPTS) + This hook defines the mechanism that will be used for exception + handling by the target. If the target has ABI specified unwind + tables, the hook should return `UI_TARGET'. If the target is to + use the `setjmp'/`longjmp'-based exception handling scheme, the + hook should return `UI_SJLJ'. If the target supports DWARF 2 + frame unwind information, the hook should return `UI_DWARF2'. + + A target may, if exceptions are disabled, choose to return + `UI_NONE'. This may end up simplifying other parts of + target-specific code. The default implementation of this hook + never returns `UI_NONE'. + + Note that the value returned by this hook should be constant. It + should not depend on anything except the command-line switches + described by OPTS. In particular, the setting `UI_SJLJ' must be + fixed at compiler start-up as C pre-processor macros and builtin + functions related to exception handling are set up depending on + this setting. + + The default implementation of the hook first honors the + `--enable-sjlj-exceptions' configure option, then + `DWARF2_UNWIND_INFO', and finally defaults to `UI_SJLJ'. If + `DWARF2_UNWIND_INFO' depends on command-line options, the target + must define this hook so that OPTS is used correctly. + + -- Target Hook: bool TARGET_UNWIND_TABLES_DEFAULT + This variable should be set to `true' if the target ABI requires + unwinding tables even when exceptions are not used. It must not + be modified by command-line option processing. + + -- Macro: DONT_USE_BUILTIN_SETJMP + Define this macro to 1 if the `setjmp'/`longjmp'-based scheme + should use the `setjmp'/`longjmp' functions from the C library + instead of the `__builtin_setjmp'/`__builtin_longjmp' machinery. + + -- Macro: DWARF_CIE_DATA_ALIGNMENT + This macro need only be defined if the target might save registers + in the function prologue at an offset to the stack pointer that is + not aligned to `UNITS_PER_WORD'. The definition should be the + negative minimum alignment if `STACK_GROWS_DOWNWARD' is defined, + and the positive minimum alignment otherwise. *Note SDB and + DWARF::. Only applicable if the target supports DWARF 2 frame + unwind information. + + -- Target Hook: bool TARGET_TERMINATE_DW2_EH_FRAME_INFO + Contains the value true if the target should add a zero word onto + the end of a Dwarf-2 frame info section when used for exception + handling. Default value is false if `EH_FRAME_SECTION_NAME' is + defined, and true otherwise. + + -- Target Hook: rtx TARGET_DWARF_REGISTER_SPAN (rtx REG) + Given a register, this hook should return a parallel of registers + to represent where to find the register pieces. Define this hook + if the register and its mode are represented in Dwarf in + non-contiguous locations, or if the register should be represented + in more than one register in Dwarf. Otherwise, this hook should + return `NULL_RTX'. If not defined, the default is to return + `NULL_RTX'. + + -- Target Hook: void TARGET_INIT_DWARF_REG_SIZES_EXTRA (tree ADDRESS) + If some registers are represented in Dwarf-2 unwind information in + multiple pieces, define this hook to fill in information about the + sizes of those pieces in the table used by the unwinder at runtime. + It will be called by `expand_builtin_init_dwarf_reg_sizes' after + filling in a single size corresponding to each hard register; + ADDRESS is the address of the table. + + -- Target Hook: bool TARGET_ASM_TTYPE (rtx SYM) + This hook is used to output a reference from a frame unwinding + table to the type_info object identified by SYM. It should return + `true' if the reference was output. Returning `false' will cause + the reference to be output using the normal Dwarf2 routines. + + -- Target Hook: bool TARGET_ARM_EABI_UNWINDER + This flag should be set to `true' on targets that use an ARM EABI + based unwinding library, and `false' on other targets. This + effects the format of unwinding tables, and how the unwinder in + entered after running a cleanup. The default is `false'. + + +File: gccint.info, Node: Alignment Output, Prev: Exception Region Output, Up: Assembler Format + +17.21.10 Assembler Commands for Alignment +----------------------------------------- + +This describes commands for alignment. + + -- Macro: JUMP_ALIGN (LABEL) + The alignment (log base 2) to put in front of LABEL, which is a + common destination of jumps and has no fallthru incoming edge. + + This macro need not be defined if you don't want any special + alignment to be done at such a time. Most machine descriptions do + not currently define the macro. + + Unless it's necessary to inspect the LABEL parameter, it is better + to set the variable ALIGN_JUMPS in the target's + `TARGET_OPTION_OVERRIDE'. Otherwise, you should try to honor the + user's selection in ALIGN_JUMPS in a `JUMP_ALIGN' implementation. + + -- Target Hook: int TARGET_ASM_JUMP_ALIGN_MAX_SKIP (rtx LABEL) + The maximum number of bytes to skip before LABEL when applying + `JUMP_ALIGN'. This works only if `ASM_OUTPUT_MAX_SKIP_ALIGN' is + defined. + + -- Macro: LABEL_ALIGN_AFTER_BARRIER (LABEL) + The alignment (log base 2) to put in front of LABEL, which follows + a `BARRIER'. + + This macro need not be defined if you don't want any special + alignment to be done at such a time. Most machine descriptions do + not currently define the macro. + + -- Target Hook: int TARGET_ASM_LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP (rtx + LABEL) + The maximum number of bytes to skip before LABEL when applying + `LABEL_ALIGN_AFTER_BARRIER'. This works only if + `ASM_OUTPUT_MAX_SKIP_ALIGN' is defined. + + -- Macro: LOOP_ALIGN (LABEL) + The alignment (log base 2) to put in front of LABEL, which follows + a `NOTE_INSN_LOOP_BEG' note. + + This macro need not be defined if you don't want any special + alignment to be done at such a time. Most machine descriptions do + not currently define the macro. + + Unless it's necessary to inspect the LABEL parameter, it is better + to set the variable `align_loops' in the target's + `TARGET_OPTION_OVERRIDE'. Otherwise, you should try to honor the + user's selection in `align_loops' in a `LOOP_ALIGN' implementation. + + -- Target Hook: int TARGET_ASM_LOOP_ALIGN_MAX_SKIP (rtx LABEL) + The maximum number of bytes to skip when applying `LOOP_ALIGN' to + LABEL. This works only if `ASM_OUTPUT_MAX_SKIP_ALIGN' is defined. + + -- Macro: LABEL_ALIGN (LABEL) + The alignment (log base 2) to put in front of LABEL. If + `LABEL_ALIGN_AFTER_BARRIER' / `LOOP_ALIGN' specify a different + alignment, the maximum of the specified values is used. + + Unless it's necessary to inspect the LABEL parameter, it is better + to set the variable `align_labels' in the target's + `TARGET_OPTION_OVERRIDE'. Otherwise, you should try to honor the + user's selection in `align_labels' in a `LABEL_ALIGN' + implementation. + + -- Target Hook: int TARGET_ASM_LABEL_ALIGN_MAX_SKIP (rtx LABEL) + The maximum number of bytes to skip when applying `LABEL_ALIGN' to + LABEL. This works only if `ASM_OUTPUT_MAX_SKIP_ALIGN' is defined. + + -- Macro: ASM_OUTPUT_SKIP (STREAM, NBYTES) + A C statement to output to the stdio stream STREAM an assembler + instruction to advance the location counter by NBYTES bytes. + Those bytes should be zero when loaded. NBYTES will be a C + expression of type `unsigned HOST_WIDE_INT'. + + -- Macro: ASM_NO_SKIP_IN_TEXT + Define this macro if `ASM_OUTPUT_SKIP' should not be used in the + text section because it fails to put zeros in the bytes that are + skipped. This is true on many Unix systems, where the pseudo-op + to skip bytes produces no-op instructions rather than zeros when + used in the text section. + + -- Macro: ASM_OUTPUT_ALIGN (STREAM, POWER) + A C statement to output to the stdio stream STREAM an assembler + command to advance the location counter to a multiple of 2 to the + POWER bytes. POWER will be a C expression of type `int'. + + -- Macro: ASM_OUTPUT_ALIGN_WITH_NOP (STREAM, POWER) + Like `ASM_OUTPUT_ALIGN', except that the "nop" instruction is used + for padding, if necessary. + + -- Macro: ASM_OUTPUT_MAX_SKIP_ALIGN (STREAM, POWER, MAX_SKIP) + A C statement to output to the stdio stream STREAM an assembler + command to advance the location counter to a multiple of 2 to the + POWER bytes, but only if MAX_SKIP or fewer bytes are needed to + satisfy the alignment request. POWER and MAX_SKIP will be a C + expression of type `int'. + + +File: gccint.info, Node: Debugging Info, Next: Floating Point, Prev: Assembler Format, Up: Target Macros + +17.22 Controlling Debugging Information Format +============================================== + +This describes how to specify debugging information. + +* Menu: + +* All Debuggers:: Macros that affect all debugging formats uniformly. +* DBX Options:: Macros enabling specific options in DBX format. +* DBX Hooks:: Hook macros for varying DBX format. +* File Names and DBX:: Macros controlling output of file names in DBX format. +* SDB and DWARF:: Macros for SDB (COFF) and DWARF formats. +* VMS Debug:: Macros for VMS debug format. + + +File: gccint.info, Node: All Debuggers, Next: DBX Options, Up: Debugging Info + +17.22.1 Macros Affecting All Debugging Formats +---------------------------------------------- + +These macros affect all debugging formats. + + -- Macro: DBX_REGISTER_NUMBER (REGNO) + A C expression that returns the DBX register number for the + compiler register number REGNO. In the default macro provided, + the value of this expression will be REGNO itself. But sometimes + there are some registers that the compiler knows about and DBX + does not, or vice versa. In such cases, some register may need to + have one number in the compiler and another for DBX. + + If two registers have consecutive numbers inside GCC, and they can + be used as a pair to hold a multiword value, then they _must_ have + consecutive numbers after renumbering with `DBX_REGISTER_NUMBER'. + Otherwise, debuggers will be unable to access such a pair, because + they expect register pairs to be consecutive in their own + numbering scheme. + + If you find yourself defining `DBX_REGISTER_NUMBER' in way that + does not preserve register pairs, then what you must do instead is + redefine the actual register numbering scheme. + + -- Macro: DEBUGGER_AUTO_OFFSET (X) + A C expression that returns the integer offset value for an + automatic variable having address X (an RTL expression). The + default computation assumes that X is based on the frame-pointer + and gives the offset from the frame-pointer. This is required for + targets that produce debugging output for DBX or COFF-style + debugging output for SDB and allow the frame-pointer to be + eliminated when the `-g' options is used. + + -- Macro: DEBUGGER_ARG_OFFSET (OFFSET, X) + A C expression that returns the integer offset value for an + argument having address X (an RTL expression). The nominal offset + is OFFSET. + + -- Macro: PREFERRED_DEBUGGING_TYPE + A C expression that returns the type of debugging output GCC should + produce when the user specifies just `-g'. Define this if you + have arranged for GCC to support more than one format of debugging + output. Currently, the allowable values are `DBX_DEBUG', + `SDB_DEBUG', `DWARF_DEBUG', `DWARF2_DEBUG', `XCOFF_DEBUG', + `VMS_DEBUG', and `VMS_AND_DWARF2_DEBUG'. + + When the user specifies `-ggdb', GCC normally also uses the value + of this macro to select the debugging output format, but with two + exceptions. If `DWARF2_DEBUGGING_INFO' is defined, GCC uses the + value `DWARF2_DEBUG'. Otherwise, if `DBX_DEBUGGING_INFO' is + defined, GCC uses `DBX_DEBUG'. + + The value of this macro only affects the default debugging output; + the user can always get a specific type of output by using + `-gstabs', `-gcoff', `-gdwarf-2', `-gxcoff', or `-gvms'. + + +File: gccint.info, Node: DBX Options, Next: DBX Hooks, Prev: All Debuggers, Up: Debugging Info + +17.22.2 Specific Options for DBX Output +--------------------------------------- + +These are specific options for DBX output. + + -- Macro: DBX_DEBUGGING_INFO + Define this macro if GCC should produce debugging output for DBX + in response to the `-g' option. + + -- Macro: XCOFF_DEBUGGING_INFO + Define this macro if GCC should produce XCOFF format debugging + output in response to the `-g' option. This is a variant of DBX + format. + + -- Macro: DEFAULT_GDB_EXTENSIONS + Define this macro to control whether GCC should by default generate + GDB's extended version of DBX debugging information (assuming + DBX-format debugging information is enabled at all). If you don't + define the macro, the default is 1: always generate the extended + information if there is any occasion to. + + -- Macro: DEBUG_SYMS_TEXT + Define this macro if all `.stabs' commands should be output while + in the text section. + + -- Macro: ASM_STABS_OP + A C string constant, including spacing, naming the assembler + pseudo op to use instead of `"\t.stabs\t"' to define an ordinary + debugging symbol. If you don't define this macro, `"\t.stabs\t"' + is used. This macro applies only to DBX debugging information + format. + + -- Macro: ASM_STABD_OP + A C string constant, including spacing, naming the assembler + pseudo op to use instead of `"\t.stabd\t"' to define a debugging + symbol whose value is the current location. If you don't define + this macro, `"\t.stabd\t"' is used. This macro applies only to + DBX debugging information format. + + -- Macro: ASM_STABN_OP + A C string constant, including spacing, naming the assembler + pseudo op to use instead of `"\t.stabn\t"' to define a debugging + symbol with no name. If you don't define this macro, + `"\t.stabn\t"' is used. This macro applies only to DBX debugging + information format. + + -- Macro: DBX_NO_XREFS + Define this macro if DBX on your system does not support the + construct `xsTAGNAME'. On some systems, this construct is used to + describe a forward reference to a structure named TAGNAME. On + other systems, this construct is not supported at all. + + -- Macro: DBX_CONTIN_LENGTH + A symbol name in DBX-format debugging information is normally + continued (split into two separate `.stabs' directives) when it + exceeds a certain length (by default, 80 characters). On some + operating systems, DBX requires this splitting; on others, + splitting must not be done. You can inhibit splitting by defining + this macro with the value zero. You can override the default + splitting-length by defining this macro as an expression for the + length you desire. + + -- Macro: DBX_CONTIN_CHAR + Normally continuation is indicated by adding a `\' character to + the end of a `.stabs' string when a continuation follows. To use + a different character instead, define this macro as a character + constant for the character you want to use. Do not define this + macro if backslash is correct for your system. + + -- Macro: DBX_STATIC_STAB_DATA_SECTION + Define this macro if it is necessary to go to the data section + before outputting the `.stabs' pseudo-op for a non-global static + variable. + + -- Macro: DBX_TYPE_DECL_STABS_CODE + The value to use in the "code" field of the `.stabs' directive for + a typedef. The default is `N_LSYM'. + + -- Macro: DBX_STATIC_CONST_VAR_CODE + The value to use in the "code" field of the `.stabs' directive for + a static variable located in the text section. DBX format does not + provide any "right" way to do this. The default is `N_FUN'. + + -- Macro: DBX_REGPARM_STABS_CODE + The value to use in the "code" field of the `.stabs' directive for + a parameter passed in registers. DBX format does not provide any + "right" way to do this. The default is `N_RSYM'. + + -- Macro: DBX_REGPARM_STABS_LETTER + The letter to use in DBX symbol data to identify a symbol as a + parameter passed in registers. DBX format does not customarily + provide any way to do this. The default is `'P''. + + -- Macro: DBX_FUNCTION_FIRST + Define this macro if the DBX information for a function and its + arguments should precede the assembler code for the function. + Normally, in DBX format, the debugging information entirely + follows the assembler code. + + -- Macro: DBX_BLOCKS_FUNCTION_RELATIVE + Define this macro, with value 1, if the value of a symbol + describing the scope of a block (`N_LBRAC' or `N_RBRAC') should be + relative to the start of the enclosing function. Normally, GCC + uses an absolute address. + + -- Macro: DBX_LINES_FUNCTION_RELATIVE + Define this macro, with value 1, if the value of a symbol + indicating the current line number (`N_SLINE') should be relative + to the start of the enclosing function. Normally, GCC uses an + absolute address. + + -- Macro: DBX_USE_BINCL + Define this macro if GCC should generate `N_BINCL' and `N_EINCL' + stabs for included header files, as on Sun systems. This macro + also directs GCC to output a type number as a pair of a file + number and a type number within the file. Normally, GCC does not + generate `N_BINCL' or `N_EINCL' stabs, and it outputs a single + number for a type number. + + +File: gccint.info, Node: DBX Hooks, Next: File Names and DBX, Prev: DBX Options, Up: Debugging Info + +17.22.3 Open-Ended Hooks for DBX Format +--------------------------------------- + +These are hooks for DBX format. + + -- Macro: DBX_OUTPUT_LBRAC (STREAM, NAME) + Define this macro to say how to output to STREAM the debugging + information for the start of a scope level for variable names. The + argument NAME is the name of an assembler symbol (for use with + `assemble_name') whose value is the address where the scope begins. + + -- Macro: DBX_OUTPUT_RBRAC (STREAM, NAME) + Like `DBX_OUTPUT_LBRAC', but for the end of a scope level. + + -- Macro: DBX_OUTPUT_NFUN (STREAM, LSCOPE_LABEL, DECL) + Define this macro if the target machine requires special handling + to output an `N_FUN' entry for the function DECL. + + -- Macro: DBX_OUTPUT_SOURCE_LINE (STREAM, LINE, COUNTER) + A C statement to output DBX debugging information before code for + line number LINE of the current source file to the stdio stream + STREAM. COUNTER is the number of time the macro was invoked, + including the current invocation; it is intended to generate + unique labels in the assembly output. + + This macro should not be defined if the default output is correct, + or if it can be made correct by defining + `DBX_LINES_FUNCTION_RELATIVE'. + + -- Macro: NO_DBX_FUNCTION_END + Some stabs encapsulation formats (in particular ECOFF), cannot + handle the `.stabs "",N_FUN,,0,0,Lscope-function-1' gdb dbx + extension construct. On those machines, define this macro to turn + this feature off without disturbing the rest of the gdb extensions. + + -- Macro: NO_DBX_BNSYM_ENSYM + Some assemblers cannot handle the `.stabd BNSYM/ENSYM,0,0' gdb dbx + extension construct. On those machines, define this macro to turn + this feature off without disturbing the rest of the gdb extensions. + + +File: gccint.info, Node: File Names and DBX, Next: SDB and DWARF, Prev: DBX Hooks, Up: Debugging Info + +17.22.4 File Names in DBX Format +-------------------------------- + +This describes file names in DBX format. + + -- Macro: DBX_OUTPUT_MAIN_SOURCE_FILENAME (STREAM, NAME) + A C statement to output DBX debugging information to the stdio + stream STREAM, which indicates that file NAME is the main source + file--the file specified as the input file for compilation. This + macro is called only once, at the beginning of compilation. + + This macro need not be defined if the standard form of output for + DBX debugging information is appropriate. + + It may be necessary to refer to a label equal to the beginning of + the text section. You can use `assemble_name (stream, + ltext_label_name)' to do so. If you do this, you must also set + the variable USED_LTEXT_LABEL_NAME to `true'. + + -- Macro: NO_DBX_MAIN_SOURCE_DIRECTORY + Define this macro, with value 1, if GCC should not emit an + indication of the current directory for compilation and current + source language at the beginning of the file. + + -- Macro: NO_DBX_GCC_MARKER + Define this macro, with value 1, if GCC should not emit an + indication that this object file was compiled by GCC. The default + is to emit an `N_OPT' stab at the beginning of every source file, + with `gcc2_compiled.' for the string and value 0. + + -- Macro: DBX_OUTPUT_MAIN_SOURCE_FILE_END (STREAM, NAME) + A C statement to output DBX debugging information at the end of + compilation of the main source file NAME. Output should be + written to the stdio stream STREAM. + + If you don't define this macro, nothing special is output at the + end of compilation, which is correct for most machines. + + -- Macro: DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END + Define this macro _instead of_ defining + `DBX_OUTPUT_MAIN_SOURCE_FILE_END', if what needs to be output at + the end of compilation is an `N_SO' stab with an empty string, + whose value is the highest absolute text address in the file. + + +File: gccint.info, Node: SDB and DWARF, Next: VMS Debug, Prev: File Names and DBX, Up: Debugging Info + +17.22.5 Macros for SDB and DWARF Output +--------------------------------------- + +Here are macros for SDB and DWARF output. + + -- Macro: SDB_DEBUGGING_INFO + Define this macro if GCC should produce COFF-style debugging output + for SDB in response to the `-g' option. + + -- Macro: DWARF2_DEBUGGING_INFO + Define this macro if GCC should produce dwarf version 2 format + debugging output in response to the `-g' option. + + -- Target Hook: int TARGET_DWARF_CALLING_CONVENTION (const_tree + FUNCTION) + Define this to enable the dwarf attribute + `DW_AT_calling_convention' to be emitted for each function. + Instead of an integer return the enum value for the `DW_CC_' + tag. + + To support optional call frame debugging information, you must also + define `INCOMING_RETURN_ADDR_RTX' and either set + `RTX_FRAME_RELATED_P' on the prologue insns if you use RTL for the + prologue, or call `dwarf2out_def_cfa' and `dwarf2out_reg_save' as + appropriate from `TARGET_ASM_FUNCTION_PROLOGUE' if you don't. + + -- Macro: DWARF2_FRAME_INFO + Define this macro to a nonzero value if GCC should always output + Dwarf 2 frame information. If `TARGET_EXCEPT_UNWIND_INFO' (*note + Exception Region Output::) returns `UI_DWARF2', and exceptions are + enabled, GCC will output this information not matter how you + define `DWARF2_FRAME_INFO'. + + -- Target Hook: enum unwind_info_type TARGET_DEBUG_UNWIND_INFO (void) + This hook defines the mechanism that will be used for describing + frame unwind information to the debugger. Normally the hook will + return `UI_DWARF2' if DWARF 2 debug information is enabled, and + return `UI_NONE' otherwise. + + A target may return `UI_DWARF2' even when DWARF 2 debug information + is disabled in order to always output DWARF 2 frame information. + + A target may return `UI_TARGET' if it has ABI specified unwind + tables. This will suppress generation of the normal debug frame + unwind information. + + -- Macro: DWARF2_ASM_LINE_DEBUG_INFO + Define this macro to be a nonzero value if the assembler can + generate Dwarf 2 line debug info sections. This will result in + much more compact line number tables, and hence is desirable if it + works. + + -- Target Hook: bool TARGET_WANT_DEBUG_PUB_SECTIONS + True if the `.debug_pubtypes' and `.debug_pubnames' sections + should be emitted. These sections are not used on most platforms, + and in particular GDB does not use them. + + -- Target Hook: bool TARGET_DELAY_SCHED2 + True if sched2 is not to be run at its normal place. This usually + means it will be run as part of machine-specific reorg. + + -- Target Hook: bool TARGET_DELAY_VARTRACK + True if vartrack is not to be run at its normal place. This + usually means it will be run as part of machine-specific reorg. + + -- Macro: ASM_OUTPUT_DWARF_DELTA (STREAM, SIZE, LABEL1, LABEL2) + A C statement to issue assembly directives that create a difference + LAB1 minus LAB2, using an integer of the given SIZE. + + -- Macro: ASM_OUTPUT_DWARF_VMS_DELTA (STREAM, SIZE, LABEL1, LABEL2) + A C statement to issue assembly directives that create a difference + between the two given labels in system defined units, e.g. + instruction slots on IA64 VMS, using an integer of the given size. + + -- Macro: ASM_OUTPUT_DWARF_OFFSET (STREAM, SIZE, LABEL, SECTION) + A C statement to issue assembly directives that create a + section-relative reference to the given LABEL, using an integer of + the given SIZE. The label is known to be defined in the given + SECTION. + + -- Macro: ASM_OUTPUT_DWARF_PCREL (STREAM, SIZE, LABEL) + A C statement to issue assembly directives that create a + self-relative reference to the given LABEL, using an integer of + the given SIZE. + + -- Macro: ASM_OUTPUT_DWARF_TABLE_REF (LABEL) + A C statement to issue assembly directives that create a reference + to the DWARF table identifier LABEL from the current section. This + is used on some systems to avoid garbage collecting a DWARF table + which is referenced by a function. + + -- Target Hook: void TARGET_ASM_OUTPUT_DWARF_DTPREL (FILE *FILE, int + SIZE, rtx X) + If defined, this target hook is a function which outputs a + DTP-relative reference to the given TLS symbol of the specified + size. + + -- Macro: PUT_SDB_... + Define these macros to override the assembler syntax for the + special SDB assembler directives. See `sdbout.c' for a list of + these macros and their arguments. If the standard syntax is used, + you need not define them yourself. + + -- Macro: SDB_DELIM + Some assemblers do not support a semicolon as a delimiter, even + between SDB assembler directives. In that case, define this macro + to be the delimiter to use (usually `\n'). It is not necessary to + define a new set of `PUT_SDB_OP' macros if this is the only change + required. + + -- Macro: SDB_ALLOW_UNKNOWN_REFERENCES + Define this macro to allow references to unknown structure, union, + or enumeration tags to be emitted. Standard COFF does not allow + handling of unknown references, MIPS ECOFF has support for it. + + -- Macro: SDB_ALLOW_FORWARD_REFERENCES + Define this macro to allow references to structure, union, or + enumeration tags that have not yet been seen to be handled. Some + assemblers choke if forward tags are used, while some require it. + + -- Macro: SDB_OUTPUT_SOURCE_LINE (STREAM, LINE) + A C statement to output SDB debugging information before code for + line number LINE of the current source file to the stdio stream + STREAM. The default is to emit an `.ln' directive. + + +File: gccint.info, Node: VMS Debug, Prev: SDB and DWARF, Up: Debugging Info + +17.22.6 Macros for VMS Debug Format +----------------------------------- + +Here are macros for VMS debug format. + + -- Macro: VMS_DEBUGGING_INFO + Define this macro if GCC should produce debugging output for VMS + in response to the `-g' option. The default behavior for VMS is + to generate minimal debug info for a traceback in the absence of + `-g' unless explicitly overridden with `-g0'. This behavior is + controlled by `TARGET_OPTION_OPTIMIZATION' and + `TARGET_OPTION_OVERRIDE'. + + +File: gccint.info, Node: Floating Point, Next: Mode Switching, Prev: Debugging Info, Up: Target Macros + +17.23 Cross Compilation and Floating Point +========================================== + +While all modern machines use twos-complement representation for +integers, there are a variety of representations for floating point +numbers. This means that in a cross-compiler the representation of +floating point numbers in the compiled program may be different from +that used in the machine doing the compilation. + + Because different representation systems may offer different amounts of +range and precision, all floating point constants must be represented in +the target machine's format. Therefore, the cross compiler cannot +safely use the host machine's floating point arithmetic; it must emulate +the target's arithmetic. To ensure consistency, GCC always uses +emulation to work with floating point values, even when the host and +target floating point formats are identical. + + The following macros are provided by `real.h' for the compiler to use. +All parts of the compiler which generate or optimize floating-point +calculations must use these macros. They may evaluate their operands +more than once, so operands must not have side effects. + + -- Macro: REAL_VALUE_TYPE + The C data type to be used to hold a floating point value in the + target machine's format. Typically this is a `struct' containing + an array of `HOST_WIDE_INT', but all code should treat it as an + opaque quantity. + + -- Macro: int REAL_VALUES_EQUAL (REAL_VALUE_TYPE X, REAL_VALUE_TYPE Y) + Compares for equality the two values, X and Y. If the target + floating point format supports negative zeroes and/or NaNs, + `REAL_VALUES_EQUAL (-0.0, 0.0)' is true, and `REAL_VALUES_EQUAL + (NaN, NaN)' is false. + + -- Macro: int REAL_VALUES_LESS (REAL_VALUE_TYPE X, REAL_VALUE_TYPE Y) + Tests whether X is less than Y. + + -- Macro: HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE X) + Truncates X to a signed integer, rounding toward zero. + + -- Macro: unsigned HOST_WIDE_INT REAL_VALUE_UNSIGNED_FIX + (REAL_VALUE_TYPE X) + Truncates X to an unsigned integer, rounding toward zero. If X is + negative, returns zero. + + -- Macro: REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *STRING, enum + machine_mode MODE) + Converts STRING into a floating point number in the target + machine's representation for mode MODE. This routine can handle + both decimal and hexadecimal floating point constants, using the + syntax defined by the C language for both. + + -- Macro: int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE X) + Returns 1 if X is negative (including negative zero), 0 otherwise. + + -- Macro: int REAL_VALUE_ISINF (REAL_VALUE_TYPE X) + Determines whether X represents infinity (positive or negative). + + -- Macro: int REAL_VALUE_ISNAN (REAL_VALUE_TYPE X) + Determines whether X represents a "NaN" (not-a-number). + + -- Macro: void REAL_ARITHMETIC (REAL_VALUE_TYPE OUTPUT, enum tree_code + CODE, REAL_VALUE_TYPE X, REAL_VALUE_TYPE Y) + Calculates an arithmetic operation on the two floating point values + X and Y, storing the result in OUTPUT (which must be a variable). + + The operation to be performed is specified by CODE. Only the + following codes are supported: `PLUS_EXPR', `MINUS_EXPR', + `MULT_EXPR', `RDIV_EXPR', `MAX_EXPR', `MIN_EXPR'. + + If `REAL_ARITHMETIC' is asked to evaluate division by zero and the + target's floating point format cannot represent infinity, it will + call `abort'. Callers should check for this situation first, using + `MODE_HAS_INFINITIES'. *Note Storage Layout::. + + -- Macro: REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE X) + Returns the negative of the floating point value X. + + -- Macro: REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE X) + Returns the absolute value of X. + + -- Macro: REAL_VALUE_TYPE REAL_VALUE_TRUNCATE (REAL_VALUE_TYPE MODE, + enum machine_mode X) + Truncates the floating point value X to fit in MODE. The return + value is still a full-size `REAL_VALUE_TYPE', but it has an + appropriate bit pattern to be output as a floating constant whose + precision accords with mode MODE. + + -- Macro: void REAL_VALUE_TO_INT (HOST_WIDE_INT LOW, HOST_WIDE_INT + HIGH, REAL_VALUE_TYPE X) + Converts a floating point value X into a double-precision integer + which is then stored into LOW and HIGH. If the value is not + integral, it is truncated. + + -- Macro: void REAL_VALUE_FROM_INT (REAL_VALUE_TYPE X, HOST_WIDE_INT + LOW, HOST_WIDE_INT HIGH, enum machine_mode MODE) + Converts a double-precision integer found in LOW and HIGH, into a + floating point value which is then stored into X. The value is + truncated to fit in mode MODE. + + +File: gccint.info, Node: Mode Switching, Next: Target Attributes, Prev: Floating Point, Up: Target Macros + +17.24 Mode Switching Instructions +================================= + +The following macros control mode switching optimizations: + + -- Macro: OPTIMIZE_MODE_SWITCHING (ENTITY) + Define this macro if the port needs extra instructions inserted + for mode switching in an optimizing compilation. + + For an example, the SH4 can perform both single and double + precision floating point operations, but to perform a single + precision operation, the FPSCR PR bit has to be cleared, while for + a double precision operation, this bit has to be set. Changing + the PR bit requires a general purpose register as a scratch + register, hence these FPSCR sets have to be inserted before + reload, i.e. you can't put this into instruction emitting or + `TARGET_MACHINE_DEPENDENT_REORG'. + + You can have multiple entities that are mode-switched, and select + at run time which entities actually need it. + `OPTIMIZE_MODE_SWITCHING' should return nonzero for any ENTITY + that needs mode-switching. If you define this macro, you also + have to define `NUM_MODES_FOR_MODE_SWITCHING', `MODE_NEEDED', + `MODE_PRIORITY_TO_MODE' and `EMIT_MODE_SET'. `MODE_AFTER', + `MODE_ENTRY', and `MODE_EXIT' are optional. + + -- Macro: NUM_MODES_FOR_MODE_SWITCHING + If you define `OPTIMIZE_MODE_SWITCHING', you have to define this as + initializer for an array of integers. Each initializer element N + refers to an entity that needs mode switching, and specifies the + number of different modes that might need to be set for this + entity. The position of the initializer in the + initializer--starting counting at zero--determines the integer + that is used to refer to the mode-switched entity in question. In + macros that take mode arguments / yield a mode result, modes are + represented as numbers 0 ... N - 1. N is used to specify that no + mode switch is needed / supplied. + + -- Macro: MODE_NEEDED (ENTITY, INSN) + ENTITY is an integer specifying a mode-switched entity. If + `OPTIMIZE_MODE_SWITCHING' is defined, you must define this macro to + return an integer value not larger than the corresponding element + in `NUM_MODES_FOR_MODE_SWITCHING', to denote the mode that ENTITY + must be switched into prior to the execution of INSN. + + -- Macro: MODE_AFTER (MODE, INSN) + If this macro is defined, it is evaluated for every INSN during + mode switching. It determines the mode that an insn results in (if + different from the incoming mode). + + -- Macro: MODE_ENTRY (ENTITY) + If this macro is defined, it is evaluated for every ENTITY that + needs mode switching. It should evaluate to an integer, which is + a mode that ENTITY is assumed to be switched to at function entry. + If `MODE_ENTRY' is defined then `MODE_EXIT' must be defined. + + -- Macro: MODE_EXIT (ENTITY) + If this macro is defined, it is evaluated for every ENTITY that + needs mode switching. It should evaluate to an integer, which is + a mode that ENTITY is assumed to be switched to at function exit. + If `MODE_EXIT' is defined then `MODE_ENTRY' must be defined. + + -- Macro: MODE_PRIORITY_TO_MODE (ENTITY, N) + This macro specifies the order in which modes for ENTITY are + processed. 0 is the highest priority, + `NUM_MODES_FOR_MODE_SWITCHING[ENTITY] - 1' the lowest. The value + of the macro should be an integer designating a mode for ENTITY. + For any fixed ENTITY, `mode_priority_to_mode' (ENTITY, N) shall be + a bijection in 0 ... `num_modes_for_mode_switching[ENTITY] - 1'. + + -- Macro: EMIT_MODE_SET (ENTITY, MODE, HARD_REGS_LIVE) + Generate one or more insns to set ENTITY to MODE. HARD_REG_LIVE + is the set of hard registers live at the point where the insn(s) + are to be inserted. + + +File: gccint.info, Node: Target Attributes, Next: Emulated TLS, Prev: Mode Switching, Up: Target Macros + +17.25 Defining target-specific uses of `__attribute__' +====================================================== + +Target-specific attributes may be defined for functions, data and types. +These are described using the following target hooks; they also need to +be documented in `extend.texi'. + + -- Target Hook: const struct attribute_spec * TARGET_ATTRIBUTE_TABLE + If defined, this target hook points to an array of `struct + attribute_spec' (defined in `tree.h') specifying the machine + specific attributes for this target and some of the restrictions + on the entities to which these attributes are applied and the + arguments they take. + + -- Target Hook: bool TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P (const_tree + NAME) + If defined, this target hook is a function which returns true if + the machine-specific attribute named NAME expects an identifier + given as its first argument to be passed on as a plain identifier, + not subjected to name lookup. If this is not defined, the default + is false for all machine-specific attributes. + + -- Target Hook: int TARGET_COMP_TYPE_ATTRIBUTES (const_tree TYPE1, + const_tree TYPE2) + If defined, this target hook is a function which returns zero if + the attributes on TYPE1 and TYPE2 are incompatible, one if they + are compatible, and two if they are nearly compatible (which + causes a warning to be generated). If this is not defined, + machine-specific attributes are supposed always to be compatible. + + -- Target Hook: void TARGET_SET_DEFAULT_TYPE_ATTRIBUTES (tree TYPE) + If defined, this target hook is a function which assigns default + attributes to the newly defined TYPE. + + -- Target Hook: tree TARGET_MERGE_TYPE_ATTRIBUTES (tree TYPE1, tree + TYPE2) + Define this target hook if the merging of type attributes needs + special handling. If defined, the result is a list of the combined + `TYPE_ATTRIBUTES' of TYPE1 and TYPE2. It is assumed that + `comptypes' has already been called and returned 1. This function + may call `merge_attributes' to handle machine-independent merging. + + -- Target Hook: tree TARGET_MERGE_DECL_ATTRIBUTES (tree OLDDECL, tree + NEWDECL) + Define this target hook if the merging of decl attributes needs + special handling. If defined, the result is a list of the combined + `DECL_ATTRIBUTES' of OLDDECL and NEWDECL. NEWDECL is a duplicate + declaration of OLDDECL. Examples of when this is needed are when + one attribute overrides another, or when an attribute is nullified + by a subsequent definition. This function may call + `merge_attributes' to handle machine-independent merging. + + If the only target-specific handling you require is `dllimport' + for Microsoft Windows targets, you should define the macro + `TARGET_DLLIMPORT_DECL_ATTRIBUTES' to `1'. The compiler will then + define a function called `merge_dllimport_decl_attributes' which + can then be defined as the expansion of + `TARGET_MERGE_DECL_ATTRIBUTES'. You can also add + `handle_dll_attribute' in the attribute table for your port to + perform initial processing of the `dllimport' and `dllexport' + attributes. This is done in `i386/cygwin.h' and `i386/i386.c', + for example. + + -- Target Hook: bool TARGET_VALID_DLLIMPORT_ATTRIBUTE_P (const_tree + DECL) + DECL is a variable or function with `__attribute__((dllimport))' + specified. Use this hook if the target needs to add extra + validation checks to `handle_dll_attribute'. + + -- Macro: TARGET_DECLSPEC + Define this macro to a nonzero value if you want to treat + `__declspec(X)' as equivalent to `__attribute((X))'. By default, + this behavior is enabled only for targets that define + `TARGET_DLLIMPORT_DECL_ATTRIBUTES'. The current implementation of + `__declspec' is via a built-in macro, but you should not rely on + this implementation detail. + + -- Target Hook: void TARGET_INSERT_ATTRIBUTES (tree NODE, tree + *ATTR_PTR) + Define this target hook if you want to be able to add attributes + to a decl when it is being created. This is normally useful for + back ends which wish to implement a pragma by using the attributes + which correspond to the pragma's effect. The NODE argument is the + decl which is being created. The ATTR_PTR argument is a pointer + to the attribute list for this decl. The list itself should not + be modified, since it may be shared with other decls, but + attributes may be chained on the head of the list and `*ATTR_PTR' + modified to point to the new attributes, or a copy of the list may + be made if further changes are needed. + + -- Target Hook: bool TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P (const_tree + FNDECL) + This target hook returns `true' if it is ok to inline FNDECL into + the current function, despite its having target-specific + attributes, `false' otherwise. By default, if a function has a + target specific attribute attached to it, it will not be inlined. + + -- Target Hook: bool TARGET_OPTION_VALID_ATTRIBUTE_P (tree FNDECL, + tree NAME, tree ARGS, int FLAGS) + This hook is called to parse the `attribute(option("..."))', and + it allows the function to set different target machine compile time + options for the current function that might be different than the + options specified on the command line. The hook should return + `true' if the options are valid. + + The hook should set the DECL_FUNCTION_SPECIFIC_TARGET field in the + function declaration to hold a pointer to a target specific STRUCT + CL_TARGET_OPTION structure. + + -- Target Hook: void TARGET_OPTION_SAVE (struct cl_target_option *PTR) + This hook is called to save any additional target specific + information in the STRUCT CL_TARGET_OPTION structure for function + specific options. *Note Option file format::. + + -- Target Hook: void TARGET_OPTION_RESTORE (struct cl_target_option + *PTR) + This hook is called to restore any additional target specific + information in the STRUCT CL_TARGET_OPTION structure for function + specific options. + + -- Target Hook: void TARGET_OPTION_PRINT (FILE *FILE, int INDENT, + struct cl_target_option *PTR) + This hook is called to print any additional target specific + information in the STRUCT CL_TARGET_OPTION structure for function + specific options. + + -- Target Hook: bool TARGET_OPTION_PRAGMA_PARSE (tree ARGS, tree + POP_TARGET) + This target hook parses the options for `#pragma GCC option' to + set the machine specific options for functions that occur later in + the input stream. The options should be the same as handled by the + `TARGET_OPTION_VALID_ATTRIBUTE_P' hook. + + -- Target Hook: void TARGET_OPTION_OVERRIDE (void) + Sometimes certain combinations of command options do not make + sense on a particular target machine. You can override the hook + `TARGET_OPTION_OVERRIDE' to take account of this. This hooks is + called once just after all the command options have been parsed. + + Don't use this hook to turn on various extra optimizations for + `-O'. That is what `TARGET_OPTION_OPTIMIZATION' is for. + + If you need to do something whenever the optimization level is + changed via the optimize attribute or pragma, see + `TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE' + + -- Target Hook: bool TARGET_CAN_INLINE_P (tree CALLER, tree CALLEE) + This target hook returns `false' if the CALLER function cannot + inline CALLEE, based on target specific information. By default, + inlining is not allowed if the callee function has function + specific target options and the caller does not use the same + options. + + +File: gccint.info, Node: Emulated TLS, Next: MIPS Coprocessors, Prev: Target Attributes, Up: Target Macros + +17.26 Emulating TLS +=================== + +For targets whose psABI does not provide Thread Local Storage via +specific relocations and instruction sequences, an emulation layer is +used. A set of target hooks allows this emulation layer to be +configured for the requirements of a particular target. For instance +the psABI may in fact specify TLS support in terms of an emulation +layer. + + The emulation layer works by creating a control object for every TLS +object. To access the TLS object, a lookup function is provided which, +when given the address of the control object, will return the address +of the current thread's instance of the TLS object. + + -- Target Hook: const char * TARGET_EMUTLS_GET_ADDRESS + Contains the name of the helper function that uses a TLS control + object to locate a TLS instance. The default causes libgcc's + emulated TLS helper function to be used. + + -- Target Hook: const char * TARGET_EMUTLS_REGISTER_COMMON + Contains the name of the helper function that should be used at + program startup to register TLS objects that are implicitly + initialized to zero. If this is `NULL', all TLS objects will have + explicit initializers. The default causes libgcc's emulated TLS + registration function to be used. + + -- Target Hook: const char * TARGET_EMUTLS_VAR_SECTION + Contains the name of the section in which TLS control variables + should be placed. The default of `NULL' allows these to be placed + in any section. + + -- Target Hook: const char * TARGET_EMUTLS_TMPL_SECTION + Contains the name of the section in which TLS initializers should + be placed. The default of `NULL' allows these to be placed in any + section. + + -- Target Hook: const char * TARGET_EMUTLS_VAR_PREFIX + Contains the prefix to be prepended to TLS control variable names. + The default of `NULL' uses a target-specific prefix. + + -- Target Hook: const char * TARGET_EMUTLS_TMPL_PREFIX + Contains the prefix to be prepended to TLS initializer objects. + The default of `NULL' uses a target-specific prefix. + + -- Target Hook: tree TARGET_EMUTLS_VAR_FIELDS (tree TYPE, tree *NAME) + Specifies a function that generates the FIELD_DECLs for a TLS + control object type. TYPE is the RECORD_TYPE the fields are for + and NAME should be filled with the structure tag, if the default of + `__emutls_object' is unsuitable. The default creates a type + suitable for libgcc's emulated TLS function. + + -- Target Hook: tree TARGET_EMUTLS_VAR_INIT (tree VAR, tree DECL, tree + TMPL_ADDR) + Specifies a function that generates the CONSTRUCTOR to initialize a + TLS control object. VAR is the TLS control object, DECL is the + TLS object and TMPL_ADDR is the address of the initializer. The + default initializes libgcc's emulated TLS control object. + + -- Target Hook: bool TARGET_EMUTLS_VAR_ALIGN_FIXED + Specifies whether the alignment of TLS control variable objects is + fixed and should not be increased as some backends may do to + optimize single objects. The default is false. + + -- Target Hook: bool TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS + Specifies whether a DWARF `DW_OP_form_tls_address' location + descriptor may be used to describe emulated TLS control objects. + + +File: gccint.info, Node: MIPS Coprocessors, Next: PCH Target, Prev: Emulated TLS, Up: Target Macros + +17.27 Defining coprocessor specifics for MIPS targets. +====================================================== + +The MIPS specification allows MIPS implementations to have as many as 4 +coprocessors, each with as many as 32 private registers. GCC supports +accessing these registers and transferring values between the registers +and memory using asm-ized variables. For example: + + register unsigned int cp0count asm ("c0r1"); + unsigned int d; + + d = cp0count + 3; + + ("c0r1" is the default name of register 1 in coprocessor 0; alternate +names may be added as described below, or the default names may be +overridden entirely in `SUBTARGET_CONDITIONAL_REGISTER_USAGE'.) + + Coprocessor registers are assumed to be epilogue-used; sets to them +will be preserved even if it does not appear that the register is used +again later in the function. + + Another note: according to the MIPS spec, coprocessor 1 (if present) is +the FPU. One accesses COP1 registers through standard mips +floating-point support; they are not included in this mechanism. + + There is one macro used in defining the MIPS coprocessor interface +which you may want to override in subtargets; it is described below. + + -- Macro: ALL_COP_ADDITIONAL_REGISTER_NAMES + A comma-separated list (with leading comma) of pairs describing the + alternate names of coprocessor registers. The format of each + entry should be + { ALTERNATENAME, REGISTER_NUMBER} + Default: empty. + + +File: gccint.info, Node: PCH Target, Next: C++ ABI, Prev: MIPS Coprocessors, Up: Target Macros + +17.28 Parameters for Precompiled Header Validity Checking +========================================================= + + -- Target Hook: void * TARGET_GET_PCH_VALIDITY (size_t *SZ) + This hook returns a pointer to the data needed by + `TARGET_PCH_VALID_P' and sets `*SZ' to the size of the data in + bytes. + + -- Target Hook: const char * TARGET_PCH_VALID_P (const void *DATA, + size_t SZ) + This hook checks whether the options used to create a PCH file are + compatible with the current settings. It returns `NULL' if so and + a suitable error message if not. Error messages will be presented + to the user and must be localized using `_(MSG)'. + + DATA is the data that was returned by `TARGET_GET_PCH_VALIDITY' + when the PCH file was created and SZ is the size of that data in + bytes. It's safe to assume that the data was created by the same + version of the compiler, so no format checking is needed. + + The default definition of `default_pch_valid_p' should be suitable + for most targets. + + -- Target Hook: const char * TARGET_CHECK_PCH_TARGET_FLAGS (int + PCH_FLAGS) + If this hook is nonnull, the default implementation of + `TARGET_PCH_VALID_P' will use it to check for compatible values of + `target_flags'. PCH_FLAGS specifies the value that `target_flags' + had when the PCH file was created. The return value is the same + as for `TARGET_PCH_VALID_P'. + + +File: gccint.info, Node: C++ ABI, Next: Named Address Spaces, Prev: PCH Target, Up: Target Macros + +17.29 C++ ABI parameters +======================== + + -- Target Hook: tree TARGET_CXX_GUARD_TYPE (void) + Define this hook to override the integer type used for guard + variables. These are used to implement one-time construction of + static objects. The default is long_long_integer_type_node. + + -- Target Hook: bool TARGET_CXX_GUARD_MASK_BIT (void) + This hook determines how guard variables are used. It should + return `false' (the default) if the first byte should be used. A + return value of `true' indicates that only the least significant + bit should be used. + + -- Target Hook: tree TARGET_CXX_GET_COOKIE_SIZE (tree TYPE) + This hook returns the size of the cookie to use when allocating an + array whose elements have the indicated TYPE. Assumes that it is + already known that a cookie is needed. The default is `max(sizeof + (size_t), alignof(type))', as defined in section 2.7 of the + IA64/Generic C++ ABI. + + -- Target Hook: bool TARGET_CXX_COOKIE_HAS_SIZE (void) + This hook should return `true' if the element size should be + stored in array cookies. The default is to return `false'. + + -- Target Hook: int TARGET_CXX_IMPORT_EXPORT_CLASS (tree TYPE, int + IMPORT_EXPORT) + If defined by a backend this hook allows the decision made to + export class TYPE to be overruled. Upon entry IMPORT_EXPORT will + contain 1 if the class is going to be exported, -1 if it is going + to be imported and 0 otherwise. This function should return the + modified value and perform any other actions necessary to support + the backend's targeted operating system. + + -- Target Hook: bool TARGET_CXX_CDTOR_RETURNS_THIS (void) + This hook should return `true' if constructors and destructors + return the address of the object created/destroyed. The default + is to return `false'. + + -- Target Hook: bool TARGET_CXX_KEY_METHOD_MAY_BE_INLINE (void) + This hook returns true if the key method for a class (i.e., the + method which, if defined in the current translation unit, causes + the virtual table to be emitted) may be an inline function. Under + the standard Itanium C++ ABI the key method may be an inline + function so long as the function is not declared inline in the + class definition. Under some variants of the ABI, an inline + function can never be the key method. The default is to return + `true'. + + -- Target Hook: void TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY (tree + DECL) + DECL is a virtual table, virtual table table, typeinfo object, or + other similar implicit class data object that will be emitted with + external linkage in this translation unit. No ELF visibility has + been explicitly specified. If the target needs to specify a + visibility other than that of the containing class, use this hook + to set `DECL_VISIBILITY' and `DECL_VISIBILITY_SPECIFIED'. + + -- Target Hook: bool TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT (void) + This hook returns true (the default) if virtual tables and other + similar implicit class data objects are always COMDAT if they have + external linkage. If this hook returns false, then class data for + classes whose virtual table will be emitted in only one translation + unit will not be COMDAT. + + -- Target Hook: bool TARGET_CXX_LIBRARY_RTTI_COMDAT (void) + This hook returns true (the default) if the RTTI information for + the basic types which is defined in the C++ runtime should always + be COMDAT, false if it should not be COMDAT. + + -- Target Hook: bool TARGET_CXX_USE_AEABI_ATEXIT (void) + This hook returns true if `__aeabi_atexit' (as defined by the ARM + EABI) should be used to register static destructors when + `-fuse-cxa-atexit' is in effect. The default is to return false + to use `__cxa_atexit'. + + -- Target Hook: bool TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT (void) + This hook returns true if the target `atexit' function can be used + in the same manner as `__cxa_atexit' to register C++ static + destructors. This requires that `atexit'-registered functions in + shared libraries are run in the correct order when the libraries + are unloaded. The default is to return false. + + -- Target Hook: void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree TYPE) + TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has + just been defined. Use this hook to make adjustments to the class + (eg, tweak visibility or perform any other required target + modifications). + + +File: gccint.info, Node: Named Address Spaces, Next: Misc, Prev: C++ ABI, Up: Target Macros + +17.30 Adding support for named address spaces +============================================= + +The draft technical report of the ISO/IEC JTC1 S22 WG14 N1275 standards +committee, `Programming Languages - C - Extensions to support embedded +processors', specifies a syntax for embedded processors to specify +alternate address spaces. You can configure a GCC port to support +section 5.1 of the draft report to add support for address spaces other +than the default address space. These address spaces are new keywords +that are similar to the `volatile' and `const' type attributes. + + Pointers to named address spaces can have a different size than +pointers to the generic address space. + + For example, the SPU port uses the `__ea' address space to refer to +memory in the host processor, rather than memory local to the SPU +processor. Access to memory in the `__ea' address space involves +issuing DMA operations to move data between the host processor and the +local processor memory address space. Pointers in the `__ea' address +space are either 32 bits or 64 bits based on the `-mea32' or `-mea64' +switches (native SPU pointers are always 32 bits). + + Internally, address spaces are represented as a small integer in the +range 0 to 15 with address space 0 being reserved for the generic +address space. + + To register a named address space qualifier keyword with the C front +end, the target may call the `c_register_addr_space' routine. For +example, the SPU port uses the following to declare `__ea' as the +keyword for named address space #1: + #define ADDR_SPACE_EA 1 + c_register_addr_space ("__ea", ADDR_SPACE_EA); + + -- Target Hook: enum machine_mode TARGET_ADDR_SPACE_POINTER_MODE + (addr_space_t ADDRESS_SPACE) + Define this to return the machine mode to use for pointers to + ADDRESS_SPACE if the target supports named address spaces. The + default version of this hook returns `ptr_mode' for the generic + address space only. + + -- Target Hook: enum machine_mode TARGET_ADDR_SPACE_ADDRESS_MODE + (addr_space_t ADDRESS_SPACE) + Define this to return the machine mode to use for addresses in + ADDRESS_SPACE if the target supports named address spaces. The + default version of this hook returns `Pmode' for the generic + address space only. + + -- Target Hook: bool TARGET_ADDR_SPACE_VALID_POINTER_MODE (enum + machine_mode MODE, addr_space_t AS) + Define this to return nonzero if the port can handle pointers with + machine mode MODE to address space AS. This target hook is the + same as the `TARGET_VALID_POINTER_MODE' target hook, except that + it includes explicit named address space support. The default + version of this hook returns true for the modes returned by either + the `TARGET_ADDR_SPACE_POINTER_MODE' or + `TARGET_ADDR_SPACE_ADDRESS_MODE' target hooks for the given + address space. + + -- Target Hook: bool TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P (enum + machine_mode MODE, rtx EXP, bool STRICT, addr_space_t AS) + Define this to return true if EXP is a valid address for mode MODE + in the named address space AS. The STRICT parameter says whether + strict addressing is in effect after reload has finished. This + target hook is the same as the `TARGET_LEGITIMATE_ADDRESS_P' + target hook, except that it includes explicit named address space + support. + + -- Target Hook: rtx TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS (rtx X, rtx + OLDX, enum machine_mode MODE, addr_space_t AS) + Define this to modify an invalid address X to be a valid address + with mode MODE in the named address space AS. This target hook is + the same as the `TARGET_LEGITIMIZE_ADDRESS' target hook, except + that it includes explicit named address space support. + + -- Target Hook: bool TARGET_ADDR_SPACE_SUBSET_P (addr_space_t + SUPERSET, addr_space_t SUBSET) + Define this to return whether the SUBSET named address space is + contained within the SUPERSET named address space. Pointers to a + named address space that is a subset of another named address space + will be converted automatically without a cast if used together in + arithmetic operations. Pointers to a superset address space can be + converted to pointers to a subset address space via explicit casts. + + -- Target Hook: rtx TARGET_ADDR_SPACE_CONVERT (rtx OP, tree FROM_TYPE, + tree TO_TYPE) + Define this to convert the pointer expression represented by the + RTL OP with type FROM_TYPE that points to a named address space to + a new pointer expression with type TO_TYPE that points to a + different named address space. When this hook it called, it is + guaranteed that one of the two address spaces is a subset of the + other, as determined by the `TARGET_ADDR_SPACE_SUBSET_P' target + hook. + + +File: gccint.info, Node: Misc, Prev: Named Address Spaces, Up: Target Macros + +17.31 Miscellaneous Parameters +============================== + +Here are several miscellaneous parameters. + + -- Macro: HAS_LONG_COND_BRANCH + Define this boolean macro to indicate whether or not your + architecture has conditional branches that can span all of memory. + It is used in conjunction with an optimization that partitions hot + and cold basic blocks into separate sections of the executable. + If this macro is set to false, gcc will convert any conditional + branches that attempt to cross between sections into unconditional + branches or indirect jumps. + + -- Macro: HAS_LONG_UNCOND_BRANCH + Define this boolean macro to indicate whether or not your + architecture has unconditional branches that can span all of + memory. It is used in conjunction with an optimization that + partitions hot and cold basic blocks into separate sections of the + executable. If this macro is set to false, gcc will convert any + unconditional branches that attempt to cross between sections into + indirect jumps. + + -- Macro: CASE_VECTOR_MODE + An alias for a machine mode name. This is the machine mode that + elements of a jump-table should have. + + -- Macro: CASE_VECTOR_SHORTEN_MODE (MIN_OFFSET, MAX_OFFSET, BODY) + Optional: return the preferred mode for an `addr_diff_vec' when + the minimum and maximum offset are known. If you define this, it + enables extra code in branch shortening to deal with + `addr_diff_vec'. To make this work, you also have to define + `INSN_ALIGN' and make the alignment for `addr_diff_vec' explicit. + The BODY argument is provided so that the offset_unsigned and scale + flags can be updated. + + -- Macro: CASE_VECTOR_PC_RELATIVE + Define this macro to be a C expression to indicate when jump-tables + should contain relative addresses. You need not define this macro + if jump-tables never contain relative addresses, or jump-tables + should contain relative addresses only when `-fPIC' or `-fPIC' is + in effect. + + -- Target Hook: unsigned int TARGET_CASE_VALUES_THRESHOLD (void) + This function return the smallest number of different values for + which it is best to use a jump-table instead of a tree of + conditional branches. The default is four for machines with a + `casesi' instruction and five otherwise. This is best for most + machines. + + -- Macro: CASE_USE_BIT_TESTS + Define this macro to be a C expression to indicate whether C switch + statements may be implemented by a sequence of bit tests. This is + advantageous on processors that can efficiently implement left + shift of 1 by the number of bits held in a register, but + inappropriate on targets that would require a loop. By default, + this macro returns `true' if the target defines an `ashlsi3' + pattern, and `false' otherwise. + + -- Macro: WORD_REGISTER_OPERATIONS + Define this macro if operations between registers with integral + mode smaller than a word are always performed on the entire + register. Most RISC machines have this property and most CISC + machines do not. + + -- Macro: LOAD_EXTEND_OP (MEM_MODE) + Define this macro to be a C expression indicating when insns that + read memory in MEM_MODE, an integral mode narrower than a word, + set the bits outside of MEM_MODE to be either the sign-extension + or the zero-extension of the data read. Return `SIGN_EXTEND' for + values of MEM_MODE for which the insn sign-extends, `ZERO_EXTEND' + for which it zero-extends, and `UNKNOWN' for other modes. + + This macro is not called with MEM_MODE non-integral or with a width + greater than or equal to `BITS_PER_WORD', so you may return any + value in this case. Do not define this macro if it would always + return `UNKNOWN'. On machines where this macro is defined, you + will normally define it as the constant `SIGN_EXTEND' or + `ZERO_EXTEND'. + + You may return a non-`UNKNOWN' value even if for some hard + registers the sign extension is not performed, if for the + `REGNO_REG_CLASS' of these hard registers + `CANNOT_CHANGE_MODE_CLASS' returns nonzero when the FROM mode is + MEM_MODE and the TO mode is any integral mode larger than this but + not larger than `word_mode'. + + You must return `UNKNOWN' if for some hard registers that allow + this mode, `CANNOT_CHANGE_MODE_CLASS' says that they cannot change + to `word_mode', but that they can change to another integral mode + that is larger then MEM_MODE but still smaller than `word_mode'. + + -- Macro: SHORT_IMMEDIATES_SIGN_EXTEND + Define this macro if loading short immediate values into registers + sign extends. + + -- Macro: FIXUNS_TRUNC_LIKE_FIX_TRUNC + Define this macro if the same instructions that convert a floating + point number to a signed fixed point number also convert validly + to an unsigned one. + + -- Target Hook: unsigned int TARGET_MIN_DIVISIONS_FOR_RECIP_MUL (enum + machine_mode MODE) + When `-ffast-math' is in effect, GCC tries to optimize divisions + by the same divisor, by turning them into multiplications by the + reciprocal. This target hook specifies the minimum number of + divisions that should be there for GCC to perform the optimization + for a variable of mode MODE. The default implementation returns 3 + if the machine has an instruction for the division, and 2 if it + does not. + + -- Macro: MOVE_MAX + The maximum number of bytes that a single instruction can move + quickly between memory and registers or between two memory + locations. + + -- Macro: MAX_MOVE_MAX + The maximum number of bytes that a single instruction can move + quickly between memory and registers or between two memory + locations. If this is undefined, the default is `MOVE_MAX'. + Otherwise, it is the constant value that is the largest value that + `MOVE_MAX' can have at run-time. + + -- Macro: SHIFT_COUNT_TRUNCATED + A C expression that is nonzero if on this machine the number of + bits actually used for the count of a shift operation is equal to + the number of bits needed to represent the size of the object + being shifted. When this macro is nonzero, the compiler will + assume that it is safe to omit a sign-extend, zero-extend, and + certain bitwise `and' instructions that truncates the count of a + shift operation. On machines that have instructions that act on + bit-fields at variable positions, which may include `bit test' + instructions, a nonzero `SHIFT_COUNT_TRUNCATED' also enables + deletion of truncations of the values that serve as arguments to + bit-field instructions. + + If both types of instructions truncate the count (for shifts) and + position (for bit-field operations), or if no variable-position + bit-field instructions exist, you should define this macro. + + However, on some machines, such as the 80386 and the 680x0, + truncation only applies to shift operations and not the (real or + pretended) bit-field operations. Define `SHIFT_COUNT_TRUNCATED' + to be zero on such machines. Instead, add patterns to the `md' + file that include the implied truncation of the shift instructions. + + You need not define this macro if it would always have the value + of zero. + + -- Target Hook: unsigned HOST_WIDE_INT TARGET_SHIFT_TRUNCATION_MASK + (enum machine_mode MODE) + This function describes how the standard shift patterns for MODE + deal with shifts by negative amounts or by more than the width of + the mode. *Note shift patterns::. + + On many machines, the shift patterns will apply a mask M to the + shift count, meaning that a fixed-width shift of X by Y is + equivalent to an arbitrary-width shift of X by Y & M. If this is + true for mode MODE, the function should return M, otherwise it + should return 0. A return value of 0 indicates that no particular + behavior is guaranteed. + + Note that, unlike `SHIFT_COUNT_TRUNCATED', this function does + _not_ apply to general shift rtxes; it applies only to instructions + that are generated by the named shift patterns. + + The default implementation of this function returns + `GET_MODE_BITSIZE (MODE) - 1' if `SHIFT_COUNT_TRUNCATED' and 0 + otherwise. This definition is always safe, but if + `SHIFT_COUNT_TRUNCATED' is false, and some shift patterns + nevertheless truncate the shift count, you may get better code by + overriding it. + + -- Macro: TRULY_NOOP_TRUNCATION (OUTPREC, INPREC) + A C expression which is nonzero if on this machine it is safe to + "convert" an integer of INPREC bits to one of OUTPREC bits (where + OUTPREC is smaller than INPREC) by merely operating on it as if it + had only OUTPREC bits. + + On many machines, this expression can be 1. + + When `TRULY_NOOP_TRUNCATION' returns 1 for a pair of sizes for + modes for which `MODES_TIEABLE_P' is 0, suboptimal code can result. + If this is the case, making `TRULY_NOOP_TRUNCATION' return 0 in + such cases may improve things. + + -- Target Hook: int TARGET_MODE_REP_EXTENDED (enum machine_mode MODE, + enum machine_mode REP_MODE) + The representation of an integral mode can be such that the values + are always extended to a wider integral mode. Return + `SIGN_EXTEND' if values of MODE are represented in sign-extended + form to REP_MODE. Return `UNKNOWN' otherwise. (Currently, none + of the targets use zero-extended representation this way so unlike + `LOAD_EXTEND_OP', `TARGET_MODE_REP_EXTENDED' is expected to return + either `SIGN_EXTEND' or `UNKNOWN'. Also no target extends MODE to + REP_MODE so that REP_MODE is not the next widest integral mode and + currently we take advantage of this fact.) + + Similarly to `LOAD_EXTEND_OP' you may return a non-`UNKNOWN' value + even if the extension is not performed on certain hard registers + as long as for the `REGNO_REG_CLASS' of these hard registers + `CANNOT_CHANGE_MODE_CLASS' returns nonzero. + + Note that `TARGET_MODE_REP_EXTENDED' and `LOAD_EXTEND_OP' describe + two related properties. If you define `TARGET_MODE_REP_EXTENDED + (mode, word_mode)' you probably also want to define + `LOAD_EXTEND_OP (mode)' to return the same type of extension. + + In order to enforce the representation of `mode', + `TRULY_NOOP_TRUNCATION' should return false when truncating to + `mode'. + + -- Macro: STORE_FLAG_VALUE + A C expression describing the value returned by a comparison + operator with an integral mode and stored by a store-flag + instruction (`cstoreMODE4') when the condition is true. This + description must apply to _all_ the `cstoreMODE4' patterns and all + the comparison operators whose results have a `MODE_INT' mode. + + A value of 1 or -1 means that the instruction implementing the + comparison operator returns exactly 1 or -1 when the comparison is + true and 0 when the comparison is false. Otherwise, the value + indicates which bits of the result are guaranteed to be 1 when the + comparison is true. This value is interpreted in the mode of the + comparison operation, which is given by the mode of the first + operand in the `cstoreMODE4' pattern. Either the low bit or the + sign bit of `STORE_FLAG_VALUE' be on. Presently, only those bits + are used by the compiler. + + If `STORE_FLAG_VALUE' is neither 1 or -1, the compiler will + generate code that depends only on the specified bits. It can also + replace comparison operators with equivalent operations if they + cause the required bits to be set, even if the remaining bits are + undefined. For example, on a machine whose comparison operators + return an `SImode' value and where `STORE_FLAG_VALUE' is defined as + `0x80000000', saying that just the sign bit is relevant, the + expression + + (ne:SI (and:SI X (const_int POWER-OF-2)) (const_int 0)) + + can be converted to + + (ashift:SI X (const_int N)) + + where N is the appropriate shift count to move the bit being + tested into the sign bit. + + There is no way to describe a machine that always sets the + low-order bit for a true value, but does not guarantee the value + of any other bits, but we do not know of any machine that has such + an instruction. If you are trying to port GCC to such a machine, + include an instruction to perform a logical-and of the result with + 1 in the pattern for the comparison operators and let us know at + <gcc@gcc.gnu.org>. + + Often, a machine will have multiple instructions that obtain a + value from a comparison (or the condition codes). Here are rules + to guide the choice of value for `STORE_FLAG_VALUE', and hence the + instructions to be used: + + * Use the shortest sequence that yields a valid definition for + `STORE_FLAG_VALUE'. It is more efficient for the compiler to + "normalize" the value (convert it to, e.g., 1 or 0) than for + the comparison operators to do so because there may be + opportunities to combine the normalization with other + operations. + + * For equal-length sequences, use a value of 1 or -1, with -1 + being slightly preferred on machines with expensive jumps and + 1 preferred on other machines. + + * As a second choice, choose a value of `0x80000001' if + instructions exist that set both the sign and low-order bits + but do not define the others. + + * Otherwise, use a value of `0x80000000'. + + Many machines can produce both the value chosen for + `STORE_FLAG_VALUE' and its negation in the same number of + instructions. On those machines, you should also define a pattern + for those cases, e.g., one matching + + (set A (neg:M (ne:M B C))) + + Some machines can also perform `and' or `plus' operations on + condition code values with less instructions than the corresponding + `cstoreMODE4' insn followed by `and' or `plus'. On those + machines, define the appropriate patterns. Use the names `incscc' + and `decscc', respectively, for the patterns which perform `plus' + or `minus' operations on condition code values. See `rs6000.md' + for some examples. The GNU Superoptimizer can be used to find + such instruction sequences on other machines. + + If this macro is not defined, the default value, 1, is used. You + need not define `STORE_FLAG_VALUE' if the machine has no store-flag + instructions, or if the value generated by these instructions is 1. + + -- Macro: FLOAT_STORE_FLAG_VALUE (MODE) + A C expression that gives a nonzero `REAL_VALUE_TYPE' value that is + returned when comparison operators with floating-point results are + true. Define this macro on machines that have comparison + operations that return floating-point values. If there are no + such operations, do not define this macro. + + -- Macro: VECTOR_STORE_FLAG_VALUE (MODE) + A C expression that gives a rtx representing the nonzero true + element for vector comparisons. The returned rtx should be valid + for the inner mode of MODE which is guaranteed to be a vector + mode. Define this macro on machines that have vector comparison + operations that return a vector result. If there are no such + operations, do not define this macro. Typically, this macro is + defined as `const1_rtx' or `constm1_rtx'. This macro may return + `NULL_RTX' to prevent the compiler optimizing such vector + comparison operations for the given mode. + + -- Macro: CLZ_DEFINED_VALUE_AT_ZERO (MODE, VALUE) + -- Macro: CTZ_DEFINED_VALUE_AT_ZERO (MODE, VALUE) + A C expression that indicates whether the architecture defines a + value for `clz' or `ctz' with a zero operand. A result of `0' + indicates the value is undefined. If the value is defined for + only the RTL expression, the macro should evaluate to `1'; if the + value applies also to the corresponding optab entry (which is + normally the case if it expands directly into the corresponding + RTL), then the macro should evaluate to `2'. In the cases where + the value is defined, VALUE should be set to this value. + + If this macro is not defined, the value of `clz' or `ctz' at zero + is assumed to be undefined. + + This macro must be defined if the target's expansion for `ffs' + relies on a particular value to get correct results. Otherwise it + is not necessary, though it may be used to optimize some corner + cases, and to provide a default expansion for the `ffs' optab. + + Note that regardless of this macro the "definedness" of `clz' and + `ctz' at zero do _not_ extend to the builtin functions visible to + the user. Thus one may be free to adjust the value at will to + match the target expansion of these operations without fear of + breaking the API. + + -- Macro: Pmode + An alias for the machine mode for pointers. On most machines, + define this to be the integer mode corresponding to the width of a + hardware pointer; `SImode' on 32-bit machine or `DImode' on 64-bit + machines. On some machines you must define this to be one of the + partial integer modes, such as `PSImode'. + + The width of `Pmode' must be at least as large as the value of + `POINTER_SIZE'. If it is not equal, you must define the macro + `POINTERS_EXTEND_UNSIGNED' to specify how pointers are extended to + `Pmode'. + + -- Macro: FUNCTION_MODE + An alias for the machine mode used for memory references to + functions being called, in `call' RTL expressions. On most CISC + machines, where an instruction can begin at any byte address, this + should be `QImode'. On most RISC machines, where all instructions + have fixed size and alignment, this should be a mode with the same + size and alignment as the machine instruction words - typically + `SImode' or `HImode'. + + -- Macro: STDC_0_IN_SYSTEM_HEADERS + In normal operation, the preprocessor expands `__STDC__' to the + constant 1, to signify that GCC conforms to ISO Standard C. On + some hosts, like Solaris, the system compiler uses a different + convention, where `__STDC__' is normally 0, but is 1 if the user + specifies strict conformance to the C Standard. + + Defining `STDC_0_IN_SYSTEM_HEADERS' makes GNU CPP follows the host + convention when processing system header files, but when + processing user files `__STDC__' will always expand to 1. + + -- Macro: NO_IMPLICIT_EXTERN_C + Define this macro if the system header files support C++ as well + as C. This macro inhibits the usual method of using system header + files in C++, which is to pretend that the file's contents are + enclosed in `extern "C" {...}'. + + -- Macro: REGISTER_TARGET_PRAGMAS () + Define this macro if you want to implement any target-specific + pragmas. If defined, it is a C expression which makes a series of + calls to `c_register_pragma' or `c_register_pragma_with_expansion' + for each pragma. The macro may also do any setup required for the + pragmas. + + The primary reason to define this macro is to provide + compatibility with other compilers for the same target. In + general, we discourage definition of target-specific pragmas for + GCC. + + If the pragma can be implemented by attributes then you should + consider defining the target hook `TARGET_INSERT_ATTRIBUTES' as + well. + + Preprocessor macros that appear on pragma lines are not expanded. + All `#pragma' directives that do not match any registered pragma + are silently ignored, unless the user specifies + `-Wunknown-pragmas'. + + -- Function: void c_register_pragma (const char *SPACE, const char + *NAME, void (*CALLBACK) (struct cpp_reader *)) + -- Function: void c_register_pragma_with_expansion (const char *SPACE, + const char *NAME, void (*CALLBACK) (struct cpp_reader *)) + Each call to `c_register_pragma' or + `c_register_pragma_with_expansion' establishes one pragma. The + CALLBACK routine will be called when the preprocessor encounters a + pragma of the form + + #pragma [SPACE] NAME ... + + SPACE is the case-sensitive namespace of the pragma, or `NULL' to + put the pragma in the global namespace. The callback routine + receives PFILE as its first argument, which can be passed on to + cpplib's functions if necessary. You can lex tokens after the + NAME by calling `pragma_lex'. Tokens that are not read by the + callback will be silently ignored. The end of the line is + indicated by a token of type `CPP_EOF'. Macro expansion occurs on + the arguments of pragmas registered with + `c_register_pragma_with_expansion' but not on the arguments of + pragmas registered with `c_register_pragma'. + + Note that the use of `pragma_lex' is specific to the C and C++ + compilers. It will not work in the Java or Fortran compilers, or + any other language compilers for that matter. Thus if + `pragma_lex' is going to be called from target-specific code, it + must only be done so when building the C and C++ compilers. This + can be done by defining the variables `c_target_objs' and + `cxx_target_objs' in the target entry in the `config.gcc' file. + These variables should name the target-specific, language-specific + object file which contains the code that uses `pragma_lex'. Note + it will also be necessary to add a rule to the makefile fragment + pointed to by `tmake_file' that shows how to build this object + file. + + -- Macro: HANDLE_PRAGMA_PACK_WITH_EXPANSION + Define this macro if macros should be expanded in the arguments of + `#pragma pack'. + + -- Target Hook: bool TARGET_HANDLE_PRAGMA_EXTERN_PREFIX + True if `#pragma extern_prefix' is to be supported. + + -- Macro: TARGET_DEFAULT_PACK_STRUCT + If your target requires a structure packing default other than 0 + (meaning the machine default), define this macro to the necessary + value (in bytes). This must be a value that would also be valid + to use with `#pragma pack()' (that is, a small power of two). + + -- Macro: DOLLARS_IN_IDENTIFIERS + Define this macro to control use of the character `$' in + identifier names for the C family of languages. 0 means `$' is + not allowed by default; 1 means it is allowed. 1 is the default; + there is no need to define this macro in that case. + + -- Macro: NO_DOLLAR_IN_LABEL + Define this macro if the assembler does not accept the character + `$' in label names. By default constructors and destructors in + G++ have `$' in the identifiers. If this macro is defined, `.' is + used instead. + + -- Macro: NO_DOT_IN_LABEL + Define this macro if the assembler does not accept the character + `.' in label names. By default constructors and destructors in G++ + have names that use `.'. If this macro is defined, these names + are rewritten to avoid `.'. + + -- Macro: INSN_SETS_ARE_DELAYED (INSN) + Define this macro as a C expression that is nonzero if it is safe + for the delay slot scheduler to place instructions in the delay + slot of INSN, even if they appear to use a resource set or + clobbered in INSN. INSN is always a `jump_insn' or an `insn'; GCC + knows that every `call_insn' has this behavior. On machines where + some `insn' or `jump_insn' is really a function call and hence has + this behavior, you should define this macro. + + You need not define this macro if it would always return zero. + + -- Macro: INSN_REFERENCES_ARE_DELAYED (INSN) + Define this macro as a C expression that is nonzero if it is safe + for the delay slot scheduler to place instructions in the delay + slot of INSN, even if they appear to set or clobber a resource + referenced in INSN. INSN is always a `jump_insn' or an `insn'. + On machines where some `insn' or `jump_insn' is really a function + call and its operands are registers whose use is actually in the + subroutine it calls, you should define this macro. Doing so + allows the delay slot scheduler to move instructions which copy + arguments into the argument registers into the delay slot of INSN. + + You need not define this macro if it would always return zero. + + -- Macro: MULTIPLE_SYMBOL_SPACES + Define this macro as a C expression that is nonzero if, in some + cases, global symbols from one translation unit may not be bound + to undefined symbols in another translation unit without user + intervention. For instance, under Microsoft Windows symbols must + be explicitly imported from shared libraries (DLLs). + + You need not define this macro if it would always evaluate to zero. + + -- Target Hook: tree TARGET_MD_ASM_CLOBBERS (tree OUTPUTS, tree + INPUTS, tree CLOBBERS) + This target hook should add to CLOBBERS `STRING_CST' trees for any + hard regs the port wishes to automatically clobber for an asm. It + should return the result of the last `tree_cons' used to add a + clobber. The OUTPUTS, INPUTS and CLOBBER lists are the + corresponding parameters to the asm and may be inspected to avoid + clobbering a register that is an input or output of the asm. You + can use `tree_overlaps_hard_reg_set', declared in `tree.h', to test + for overlap with regards to asm-declared registers. + + -- Macro: MATH_LIBRARY + Define this macro as a C string constant for the linker argument + to link in the system math library, minus the initial `"-l"', or + `""' if the target does not have a separate math library. + + You need only define this macro if the default of `"m"' is wrong. + + -- Macro: LIBRARY_PATH_ENV + Define this macro as a C string constant for the environment + variable that specifies where the linker should look for libraries. + + You need only define this macro if the default of `"LIBRARY_PATH"' + is wrong. + + -- Macro: TARGET_POSIX_IO + Define this macro if the target supports the following POSIX file + functions, access, mkdir and file locking with fcntl / F_SETLKW. + Defining `TARGET_POSIX_IO' will enable the test coverage code to + use file locking when exiting a program, which avoids race + conditions if the program has forked. It will also create + directories at run-time for cross-profiling. + + -- Macro: MAX_CONDITIONAL_EXECUTE + A C expression for the maximum number of instructions to execute + via conditional execution instructions instead of a branch. A + value of `BRANCH_COST'+1 is the default if the machine does not + use cc0, and 1 if it does use cc0. + + -- Macro: IFCVT_MODIFY_TESTS (CE_INFO, TRUE_EXPR, FALSE_EXPR) + Used if the target needs to perform machine-dependent + modifications on the conditionals used for turning basic blocks + into conditionally executed code. CE_INFO points to a data + structure, `struct ce_if_block', which contains information about + the currently processed blocks. TRUE_EXPR and FALSE_EXPR are the + tests that are used for converting the then-block and the + else-block, respectively. Set either TRUE_EXPR or FALSE_EXPR to a + null pointer if the tests cannot be converted. + + -- Macro: IFCVT_MODIFY_MULTIPLE_TESTS (CE_INFO, BB, TRUE_EXPR, + FALSE_EXPR) + Like `IFCVT_MODIFY_TESTS', but used when converting more + complicated if-statements into conditions combined by `and' and + `or' operations. BB contains the basic block that contains the + test that is currently being processed and about to be turned into + a condition. + + -- Macro: IFCVT_MODIFY_INSN (CE_INFO, PATTERN, INSN) + A C expression to modify the PATTERN of an INSN that is to be + converted to conditional execution format. CE_INFO points to a + data structure, `struct ce_if_block', which contains information + about the currently processed blocks. + + -- Macro: IFCVT_MODIFY_FINAL (CE_INFO) + A C expression to perform any final machine dependent + modifications in converting code to conditional execution. The + involved basic blocks can be found in the `struct ce_if_block' + structure that is pointed to by CE_INFO. + + -- Macro: IFCVT_MODIFY_CANCEL (CE_INFO) + A C expression to cancel any machine dependent modifications in + converting code to conditional execution. The involved basic + blocks can be found in the `struct ce_if_block' structure that is + pointed to by CE_INFO. + + -- Macro: IFCVT_INIT_EXTRA_FIELDS (CE_INFO) + A C expression to initialize any extra fields in a `struct + ce_if_block' structure, which are defined by the + `IFCVT_EXTRA_FIELDS' macro. + + -- Macro: IFCVT_EXTRA_FIELDS + If defined, it should expand to a set of field declarations that + will be added to the `struct ce_if_block' structure. These should + be initialized by the `IFCVT_INIT_EXTRA_FIELDS' macro. + + -- Target Hook: void TARGET_MACHINE_DEPENDENT_REORG (void) + If non-null, this hook performs a target-specific pass over the + instruction stream. The compiler will run it at all optimization + levels, just before the point at which it normally does + delayed-branch scheduling. + + The exact purpose of the hook varies from target to target. Some + use it to do transformations that are necessary for correctness, + such as laying out in-function constant pools or avoiding hardware + hazards. Others use it as an opportunity to do some + machine-dependent optimizations. + + You need not implement the hook if it has nothing to do. The + default definition is null. + + -- Target Hook: void TARGET_INIT_BUILTINS (void) + Define this hook if you have any machine-specific built-in + functions that need to be defined. It should be a function that + performs the necessary setup. + + Machine specific built-in functions can be useful to expand + special machine instructions that would otherwise not normally be + generated because they have no equivalent in the source language + (for example, SIMD vector instructions or prefetch instructions). + + To create a built-in function, call the function + `lang_hooks.builtin_function' which is defined by the language + front end. You can use any type nodes set up by + `build_common_tree_nodes' and `build_common_tree_nodes_2'; only + language front ends that use those two functions will call + `TARGET_INIT_BUILTINS'. + + -- Target Hook: tree TARGET_BUILTIN_DECL (unsigned CODE, bool + INITIALIZE_P) + Define this hook if you have any machine-specific built-in + functions that need to be defined. It should be a function that + returns the builtin function declaration for the builtin function + code CODE. If there is no such builtin and it cannot be + initialized at this time if INITIALIZE_P is true the function + should return `NULL_TREE'. If CODE is out of range the function + should return `error_mark_node'. + + -- Target Hook: rtx TARGET_EXPAND_BUILTIN (tree EXP, rtx TARGET, rtx + SUBTARGET, enum machine_mode MODE, int IGNORE) + Expand a call to a machine specific built-in function that was set + up by `TARGET_INIT_BUILTINS'. EXP is the expression for the + function call; the result should go to TARGET if that is + convenient, and have mode MODE if that is convenient. SUBTARGET + may be used as the target for computing one of EXP's operands. + IGNORE is nonzero if the value is to be ignored. This function + should return the result of the call to the built-in function. + + -- Target Hook: tree TARGET_RESOLVE_OVERLOADED_BUILTIN (unsigned int + LOC, tree FNDECL, void *ARGLIST) + Select a replacement for a machine specific built-in function that + was set up by `TARGET_INIT_BUILTINS'. This is done _before_ + regular type checking, and so allows the target to implement a + crude form of function overloading. FNDECL is the declaration of + the built-in function. ARGLIST is the list of arguments passed to + the built-in function. The result is a complete expression that + implements the operation, usually another `CALL_EXPR'. ARGLIST + really has type `VEC(tree,gc)*' + + -- Target Hook: tree TARGET_FOLD_BUILTIN (tree FNDECL, int N_ARGS, + tree *ARGP, bool IGNORE) + Fold a call to a machine specific built-in function that was set + up by `TARGET_INIT_BUILTINS'. FNDECL is the declaration of the + built-in function. N_ARGS is the number of arguments passed to + the function; the arguments themselves are pointed to by ARGP. + The result is another tree containing a simplified expression for + the call's result. If IGNORE is true the value will be ignored. + + -- Target Hook: int TARGET_MVERSION_FUNCTION (tree FNDECL, tree + *OPTIMIZATION_NODE_CHAIN, tree *COND_FUNC_DECL) + Check if a function needs to be multi-versioned to support + variants of this architecture. FNDECL is the declaration of the + function. + + -- Target Hook: bool TARGET_SLOW_UNALIGNED_VECTOR_MEMOP (void) + Return true if unaligned vector memory load/store is a slow + operation on this target. + + -- Target Hook: const char * TARGET_INVALID_WITHIN_DOLOOP (const_rtx + INSN) + Take an instruction in INSN and return NULL if it is valid within a + low-overhead loop, otherwise return a string explaining why doloop + could not be applied. + + Many targets use special registers for low-overhead looping. For + any instruction that clobbers these this function should return a + string indicating the reason why the doloop could not be applied. + By default, the RTL loop optimizer does not use a present doloop + pattern for loops containing function calls or branch on table + instructions. + + -- Macro: MD_CAN_REDIRECT_BRANCH (BRANCH1, BRANCH2) + Take a branch insn in BRANCH1 and another in BRANCH2. Return true + if redirecting BRANCH1 to the destination of BRANCH2 is possible. + + On some targets, branches may have a limited range. Optimizing the + filling of delay slots can result in branches being redirected, + and this may in turn cause a branch offset to overflow. + + -- Target Hook: bool TARGET_COMMUTATIVE_P (const_rtx X, int OUTER_CODE) + This target hook returns `true' if X is considered to be + commutative. Usually, this is just COMMUTATIVE_P (X), but the HP + PA doesn't consider PLUS to be commutative inside a MEM. + OUTER_CODE is the rtx code of the enclosing rtl, if known, + otherwise it is UNKNOWN. + + -- Target Hook: rtx TARGET_ALLOCATE_INITIAL_VALUE (rtx HARD_REG) + When the initial value of a hard register has been copied in a + pseudo register, it is often not necessary to actually allocate + another register to this pseudo register, because the original + hard register or a stack slot it has been saved into can be used. + `TARGET_ALLOCATE_INITIAL_VALUE' is called at the start of register + allocation once for each hard register that had its initial value + copied by using `get_func_hard_reg_initial_val' or + `get_hard_reg_initial_val'. Possible values are `NULL_RTX', if + you don't want to do any special allocation, a `REG' rtx--that + would typically be the hard register itself, if it is known not to + be clobbered--or a `MEM'. If you are returning a `MEM', this is + only a hint for the allocator; it might decide to use another + register anyways. You may use `current_function_leaf_function' in + the hook, functions that use `REG_N_SETS', to determine if the hard + register in question will not be clobbered. The default value of + this hook is `NULL', which disables any special allocation. + + -- Target Hook: int TARGET_UNSPEC_MAY_TRAP_P (const_rtx X, unsigned + FLAGS) + This target hook returns nonzero if X, an `unspec' or + `unspec_volatile' operation, might cause a trap. Targets can use + this hook to enhance precision of analysis for `unspec' and + `unspec_volatile' operations. You may call `may_trap_p_1' to + analyze inner elements of X in which case FLAGS should be passed + along. + + -- Target Hook: void TARGET_SET_CURRENT_FUNCTION (tree DECL) + The compiler invokes this hook whenever it changes its current + function context (`cfun'). You can define this function if the + back end needs to perform any initialization or reset actions on a + per-function basis. For example, it may be used to implement + function attributes that affect register usage or code generation + patterns. The argument DECL is the declaration for the new + function context, and may be null to indicate that the compiler + has left a function context and is returning to processing at the + top level. The default hook function does nothing. + + GCC sets `cfun' to a dummy function context during initialization + of some parts of the back end. The hook function is not invoked + in this situation; you need not worry about the hook being invoked + recursively, or when the back end is in a partially-initialized + state. `cfun' might be `NULL' to indicate processing at top level, + outside of any function scope. + + -- Macro: TARGET_OBJECT_SUFFIX + Define this macro to be a C string representing the suffix for + object files on your target machine. If you do not define this + macro, GCC will use `.o' as the suffix for object files. + + -- Macro: TARGET_EXECUTABLE_SUFFIX + Define this macro to be a C string representing the suffix to be + automatically added to executable files on your target machine. + If you do not define this macro, GCC will use the null string as + the suffix for executable files. + + -- Macro: COLLECT_EXPORT_LIST + If defined, `collect2' will scan the individual object files + specified on its command line and create an export list for the + linker. Define this macro for systems like AIX, where the linker + discards object files that are not referenced from `main' and uses + export lists. + + -- Macro: MODIFY_JNI_METHOD_CALL (MDECL) + Define this macro to a C expression representing a variant of the + method call MDECL, if Java Native Interface (JNI) methods must be + invoked differently from other methods on your target. For + example, on 32-bit Microsoft Windows, JNI methods must be invoked + using the `stdcall' calling convention and this macro is then + defined as this expression: + + build_type_attribute_variant (MDECL, + build_tree_list + (get_identifier ("stdcall"), + NULL)) + + -- Target Hook: bool TARGET_CANNOT_MODIFY_JUMPS_P (void) + This target hook returns `true' past the point in which new jump + instructions could be created. On machines that require a + register for every jump such as the SHmedia ISA of SH5, this point + would typically be reload, so this target hook should be defined + to a function such as: + + static bool + cannot_modify_jumps_past_reload_p () + { + return (reload_completed || reload_in_progress); + } + + -- Target Hook: reg_class_t TARGET_BRANCH_TARGET_REGISTER_CLASS (void) + This target hook returns a register class for which branch target + register optimizations should be applied. All registers in this + class should be usable interchangeably. After reload, registers + in this class will be re-allocated and loads will be hoisted out + of loops and be subjected to inter-block scheduling. + + -- Target Hook: bool TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED (bool + AFTER_PROLOGUE_EPILOGUE_GEN) + Branch target register optimization will by default exclude + callee-saved registers that are not already live during the + current function; if this target hook returns true, they will be + included. The target code must than make sure that all target + registers in the class returned by + `TARGET_BRANCH_TARGET_REGISTER_CLASS' that might need saving are + saved. AFTER_PROLOGUE_EPILOGUE_GEN indicates if prologues and + epilogues have already been generated. Note, even if you only + return true when AFTER_PROLOGUE_EPILOGUE_GEN is false, you still + are likely to have to make special provisions in + `INITIAL_ELIMINATION_OFFSET' to reserve space for caller-saved + target registers. + + -- Target Hook: bool TARGET_HAVE_CONDITIONAL_EXECUTION (void) + This target hook returns true if the target supports conditional + execution. This target hook is required only when the target has + several different modes and they have different conditional + execution capability, such as ARM. + + -- Target Hook: unsigned TARGET_LOOP_UNROLL_ADJUST (unsigned NUNROLL, + struct loop *LOOP) + This target hook returns a new value for the number of times LOOP + should be unrolled. The parameter NUNROLL is the number of times + the loop is to be unrolled. The parameter LOOP is a pointer to the + loop, which is going to be checked for unrolling. This target hook + is required only when the target has special constraints like + maximum number of memory accesses. + + -- Macro: POWI_MAX_MULTS + If defined, this macro is interpreted as a signed integer C + expression that specifies the maximum number of floating point + multiplications that should be emitted when expanding + exponentiation by an integer constant inline. When this value is + defined, exponentiation requiring more than this number of + multiplications is implemented by calling the system library's + `pow', `powf' or `powl' routines. The default value places no + upper bound on the multiplication count. + + -- Macro: void TARGET_EXTRA_INCLUDES (const char *SYSROOT, const char + *IPREFIX, int STDINC) + This target hook should register any extra include files for the + target. The parameter STDINC indicates if normal include files + are present. The parameter SYSROOT is the system root directory. + The parameter IPREFIX is the prefix for the gcc directory. + + -- Macro: void TARGET_EXTRA_PRE_INCLUDES (const char *SYSROOT, const + char *IPREFIX, int STDINC) + This target hook should register any extra include files for the + target before any standard headers. The parameter STDINC + indicates if normal include files are present. The parameter + SYSROOT is the system root directory. The parameter IPREFIX is + the prefix for the gcc directory. + + -- Macro: void TARGET_OPTF (char *PATH) + This target hook should register special include paths for the + target. The parameter PATH is the include to register. On Darwin + systems, this is used for Framework includes, which have semantics + that are different from `-I'. + + -- Macro: bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree FNDECL) + This target macro returns `true' if it is safe to use a local alias + for a virtual function FNDECL when constructing thunks, `false' + otherwise. By default, the macro returns `true' for all + functions, if a target supports aliases (i.e. defines + `ASM_OUTPUT_DEF'), `false' otherwise, + + -- Macro: TARGET_FORMAT_TYPES + If defined, this macro is the name of a global variable containing + target-specific format checking information for the `-Wformat' + option. The default is to have no target-specific format checks. + + -- Macro: TARGET_N_FORMAT_TYPES + If defined, this macro is the number of entries in + `TARGET_FORMAT_TYPES'. + + -- Macro: TARGET_OVERRIDES_FORMAT_ATTRIBUTES + If defined, this macro is the name of a global variable containing + target-specific format overrides for the `-Wformat' option. The + default is to have no target-specific format overrides. If defined, + `TARGET_FORMAT_TYPES' must be defined, too. + + -- Macro: TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT + If defined, this macro specifies the number of entries in + `TARGET_OVERRIDES_FORMAT_ATTRIBUTES'. + + -- Macro: TARGET_OVERRIDES_FORMAT_INIT + If defined, this macro specifies the optional initialization + routine for target specific customizations of the system printf + and scanf formatter settings. + + -- Target Hook: bool TARGET_RELAXED_ORDERING + If set to `true', means that the target's memory model does not + guarantee that loads which do not depend on one another will access + main memory in the order of the instruction stream; if ordering is + important, an explicit memory barrier must be used. This is true + of many recent processors which implement a policy of "relaxed," + "weak," or "release" memory consistency, such as Alpha, PowerPC, + and ia64. The default is `false'. + + -- Target Hook: const char * TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN + (const_tree TYPELIST, const_tree FUNCDECL, const_tree VAL) + If defined, this macro returns the diagnostic message when it is + illegal to pass argument VAL to function FUNCDECL with prototype + TYPELIST. + + -- Target Hook: const char * TARGET_INVALID_CONVERSION (const_tree + FROMTYPE, const_tree TOTYPE) + If defined, this macro returns the diagnostic message when it is + invalid to convert from FROMTYPE to TOTYPE, or `NULL' if validity + should be determined by the front end. + + -- Target Hook: const char * TARGET_INVALID_UNARY_OP (int OP, + const_tree TYPE) + If defined, this macro returns the diagnostic message when it is + invalid to apply operation OP (where unary plus is denoted by + `CONVERT_EXPR') to an operand of type TYPE, or `NULL' if validity + should be determined by the front end. + + -- Target Hook: const char * TARGET_INVALID_BINARY_OP (int OP, + const_tree TYPE1, const_tree TYPE2) + If defined, this macro returns the diagnostic message when it is + invalid to apply operation OP to operands of types TYPE1 and + TYPE2, or `NULL' if validity should be determined by the front end. + + -- Target Hook: const char * TARGET_INVALID_PARAMETER_TYPE (const_tree + TYPE) + If defined, this macro returns the diagnostic message when it is + invalid for functions to include parameters of type TYPE, or + `NULL' if validity should be determined by the front end. This is + currently used only by the C and C++ front ends. + + -- Target Hook: const char * TARGET_INVALID_RETURN_TYPE (const_tree + TYPE) + If defined, this macro returns the diagnostic message when it is + invalid for functions to have return type TYPE, or `NULL' if + validity should be determined by the front end. This is currently + used only by the C and C++ front ends. + + -- Target Hook: tree TARGET_PROMOTED_TYPE (const_tree TYPE) + If defined, this target hook returns the type to which values of + TYPE should be promoted when they appear in expressions, analogous + to the integer promotions, or `NULL_TREE' to use the front end's + normal promotion rules. This hook is useful when there are + target-specific types with special promotion rules. This is + currently used only by the C and C++ front ends. + + -- Target Hook: tree TARGET_CONVERT_TO_TYPE (tree TYPE, tree EXPR) + If defined, this hook returns the result of converting EXPR to + TYPE. It should return the converted expression, or `NULL_TREE' + to apply the front end's normal conversion rules. This hook is + useful when there are target-specific types with special + conversion rules. This is currently used only by the C and C++ + front ends. + + -- Macro: TARGET_USE_JCR_SECTION + This macro determines whether to use the JCR section to register + Java classes. By default, TARGET_USE_JCR_SECTION is defined to 1 + if both SUPPORTS_WEAK and TARGET_HAVE_NAMED_SECTIONS are true, + else 0. + + -- Macro: OBJC_JBLEN + This macro determines the size of the objective C jump buffer for + the NeXT runtime. By default, OBJC_JBLEN is defined to an + innocuous value. + + -- Macro: LIBGCC2_UNWIND_ATTRIBUTE + Define this macro if any target-specific attributes need to be + attached to the functions in `libgcc' that provide low-level + support for call stack unwinding. It is used in declarations in + `unwind-generic.h' and the associated definitions of those + functions. + + -- Target Hook: void TARGET_UPDATE_STACK_BOUNDARY (void) + Define this macro to update the current function stack boundary if + necessary. + + -- Target Hook: rtx TARGET_GET_DRAP_RTX (void) + This hook should return an rtx for Dynamic Realign Argument + Pointer (DRAP) if a different argument pointer register is needed + to access the function's argument list due to stack realignment. + Return `NULL' if no DRAP is needed. + + -- Target Hook: bool TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS (void) + When optimization is disabled, this hook indicates whether or not + arguments should be allocated to stack slots. Normally, GCC + allocates stacks slots for arguments when not optimizing in order + to make debugging easier. However, when a function is declared + with `__attribute__((naked))', there is no stack frame, and the + compiler cannot safely move arguments from the registers in which + they are passed to the stack. Therefore, this hook should return + true in general, but false for naked functions. The default + implementation always returns true. + + -- Target Hook: unsigned HOST_WIDE_INT TARGET_CONST_ANCHOR + On some architectures it can take multiple instructions to + synthesize a constant. If there is another constant already in a + register that is close enough in value then it is preferable that + the new constant is computed from this register using immediate + addition or subtraction. We accomplish this through CSE. Besides + the value of the constant we also add a lower and an upper + constant anchor to the available expressions. These are then + queried when encountering new constants. The anchors are computed + by rounding the constant up and down to a multiple of the value of + `TARGET_CONST_ANCHOR'. `TARGET_CONST_ANCHOR' should be the + maximum positive value accepted by immediate-add plus one. We + currently assume that the value of `TARGET_CONST_ANCHOR' is a + power of 2. For example, on MIPS, where add-immediate takes a + 16-bit signed value, `TARGET_CONST_ANCHOR' is set to `0x8000'. + The default value is zero, which disables this optimization. + + +File: gccint.info, Node: Host Config, Next: Fragments, Prev: Target Macros, Up: Top + +18 Host Configuration +********************* + +Most details about the machine and system on which the compiler is +actually running are detected by the `configure' script. Some things +are impossible for `configure' to detect; these are described in two +ways, either by macros defined in a file named `xm-MACHINE.h' or by +hook functions in the file specified by the OUT_HOST_HOOK_OBJ variable +in `config.gcc'. (The intention is that very few hosts will need a +header file but nearly every fully supported host will need to override +some hooks.) + + If you need to define only a few macros, and they have simple +definitions, consider using the `xm_defines' variable in your +`config.gcc' entry instead of creating a host configuration header. +*Note System Config::. + +* Menu: + +* Host Common:: Things every host probably needs implemented. +* Filesystem:: Your host can't have the letter `a' in filenames? +* Host Misc:: Rare configuration options for hosts. + + +File: gccint.info, Node: Host Common, Next: Filesystem, Up: Host Config + +18.1 Host Common +================ + +Some things are just not portable, even between similar operating +systems, and are too difficult for autoconf to detect. They get +implemented using hook functions in the file specified by the +HOST_HOOK_OBJ variable in `config.gcc'. + + -- Host Hook: void HOST_HOOKS_EXTRA_SIGNALS (void) + This host hook is used to set up handling for extra signals. The + most common thing to do in this hook is to detect stack overflow. + + -- Host Hook: void * HOST_HOOKS_GT_PCH_GET_ADDRESS (size_t SIZE, int + FD) + This host hook returns the address of some space that is likely to + be free in some subsequent invocation of the compiler. We intend + to load the PCH data at this address such that the data need not + be relocated. The area should be able to hold SIZE bytes. If the + host uses `mmap', FD is an open file descriptor that can be used + for probing. + + -- Host Hook: int HOST_HOOKS_GT_PCH_USE_ADDRESS (void * ADDRESS, + size_t SIZE, int FD, size_t OFFSET) + This host hook is called when a PCH file is about to be loaded. + We want to load SIZE bytes from FD at OFFSET into memory at + ADDRESS. The given address will be the result of a previous + invocation of `HOST_HOOKS_GT_PCH_GET_ADDRESS'. Return -1 if we + couldn't allocate SIZE bytes at ADDRESS. Return 0 if the memory + is allocated but the data is not loaded. Return 1 if the hook has + performed everything. + + If the implementation uses reserved address space, free any + reserved space beyond SIZE, regardless of the return value. If no + PCH will be loaded, this hook may be called with SIZE zero, in + which case all reserved address space should be freed. + + Do not try to handle values of ADDRESS that could not have been + returned by this executable; just return -1. Such values usually + indicate an out-of-date PCH file (built by some other GCC + executable), and such a PCH file won't work. + + -- Host Hook: size_t HOST_HOOKS_GT_PCH_ALLOC_GRANULARITY (void); + This host hook returns the alignment required for allocating + virtual memory. Usually this is the same as getpagesize, but on + some hosts the alignment for reserving memory differs from the + pagesize for committing memory. + + +File: gccint.info, Node: Filesystem, Next: Host Misc, Prev: Host Common, Up: Host Config + +18.2 Host Filesystem +==================== + +GCC needs to know a number of things about the semantics of the host +machine's filesystem. Filesystems with Unix and MS-DOS semantics are +automatically detected. For other systems, you can define the +following macros in `xm-MACHINE.h'. + +`HAVE_DOS_BASED_FILE_SYSTEM' + This macro is automatically defined by `system.h' if the host file + system obeys the semantics defined by MS-DOS instead of Unix. DOS + file systems are case insensitive, file specifications may begin + with a drive letter, and both forward slash and backslash (`/' and + `\') are directory separators. + +`DIR_SEPARATOR' +`DIR_SEPARATOR_2' + If defined, these macros expand to character constants specifying + separators for directory names within a file specification. + `system.h' will automatically give them appropriate values on Unix + and MS-DOS file systems. If your file system is neither of these, + define one or both appropriately in `xm-MACHINE.h'. + + However, operating systems like VMS, where constructing a pathname + is more complicated than just stringing together directory names + separated by a special character, should not define either of these + macros. + +`PATH_SEPARATOR' + If defined, this macro should expand to a character constant + specifying the separator for elements of search paths. The default + value is a colon (`:'). DOS-based systems usually, but not + always, use semicolon (`;'). + +`VMS' + Define this macro if the host system is VMS. + +`HOST_OBJECT_SUFFIX' + Define this macro to be a C string representing the suffix for + object files on your host machine. If you do not define this + macro, GCC will use `.o' as the suffix for object files. + +`HOST_EXECUTABLE_SUFFIX' + Define this macro to be a C string representing the suffix for + executable files on your host machine. If you do not define this + macro, GCC will use the null string as the suffix for executable + files. + +`HOST_BIT_BUCKET' + A pathname defined by the host operating system, which can be + opened as a file and written to, but all the information written + is discarded. This is commonly known as a "bit bucket" or "null + device". If you do not define this macro, GCC will use + `/dev/null' as the bit bucket. If the host does not support a bit + bucket, define this macro to an invalid filename. + +`UPDATE_PATH_HOST_CANONICALIZE (PATH)' + If defined, a C statement (sans semicolon) that performs + host-dependent canonicalization when a path used in a compilation + driver or preprocessor is canonicalized. PATH is a malloc-ed path + to be canonicalized. If the C statement does canonicalize PATH + into a different buffer, the old path should be freed and the new + buffer should have been allocated with malloc. + +`DUMPFILE_FORMAT' + Define this macro to be a C string representing the format to use + for constructing the index part of debugging dump file names. The + resultant string must fit in fifteen bytes. The full filename + will be the concatenation of: the prefix of the assembler file + name, the string resulting from applying this format to an index + number, and a string unique to each dump file kind, e.g. `rtl'. + + If you do not define this macro, GCC will use `.%02d.'. You should + define this macro if using the default will create an invalid file + name. + +`DELETE_IF_ORDINARY' + Define this macro to be a C statement (sans semicolon) that + performs host-dependent removal of ordinary temp files in the + compilation driver. + + If you do not define this macro, GCC will use the default version. + You should define this macro if the default version does not + reliably remove the temp file as, for example, on VMS which allows + multiple versions of a file. + +`HOST_LACKS_INODE_NUMBERS' + Define this macro if the host filesystem does not report + meaningful inode numbers in struct stat. + + +File: gccint.info, Node: Host Misc, Prev: Filesystem, Up: Host Config + +18.3 Host Misc +============== + +`FATAL_EXIT_CODE' + A C expression for the status code to be returned when the compiler + exits after serious errors. The default is the system-provided + macro `EXIT_FAILURE', or `1' if the system doesn't define that + macro. Define this macro only if these defaults are incorrect. + +`SUCCESS_EXIT_CODE' + A C expression for the status code to be returned when the compiler + exits without serious errors. (Warnings are not serious errors.) + The default is the system-provided macro `EXIT_SUCCESS', or `0' if + the system doesn't define that macro. Define this macro only if + these defaults are incorrect. + +`USE_C_ALLOCA' + Define this macro if GCC should use the C implementation of + `alloca' provided by `libiberty.a'. This only affects how some + parts of the compiler itself allocate memory. It does not change + code generation. + + When GCC is built with a compiler other than itself, the C `alloca' + is always used. This is because most other implementations have + serious bugs. You should define this macro only on a system where + no stack-based `alloca' can possibly work. For instance, if a + system has a small limit on the size of the stack, GCC's builtin + `alloca' will not work reliably. + +`COLLECT2_HOST_INITIALIZATION' + If defined, a C statement (sans semicolon) that performs + host-dependent initialization when `collect2' is being initialized. + +`GCC_DRIVER_HOST_INITIALIZATION' + If defined, a C statement (sans semicolon) that performs + host-dependent initialization when a compilation driver is being + initialized. + +`HOST_LONG_LONG_FORMAT' + If defined, the string used to indicate an argument of type `long + long' to functions like `printf'. The default value is `"ll"'. + +`HOST_LONG_FORMAT' + If defined, the string used to indicate an argument of type `long' + to functions like `printf'. The default value is `"l"'. + +`HOST_PTR_PRINTF' + If defined, the string used to indicate an argument of type `void + *' to functions like `printf'. The default value is `"%p"'. + + In addition, if `configure' generates an incorrect definition of any +of the macros in `auto-host.h', you can override that definition in a +host configuration header. If you need to do this, first see if it is +possible to fix `configure'. + + +File: gccint.info, Node: Fragments, Next: Collect2, Prev: Host Config, Up: Top + +19 Makefile Fragments +********************* + +When you configure GCC using the `configure' script, it will construct +the file `Makefile' from the template file `Makefile.in'. When it does +this, it can incorporate makefile fragments from the `config' +directory. These are used to set Makefile parameters that are not +amenable to being calculated by autoconf. The list of fragments to +incorporate is set by `config.gcc' (and occasionally `config.build' and +`config.host'); *Note System Config::. + + Fragments are named either `t-TARGET' or `x-HOST', depending on +whether they are relevant to configuring GCC to produce code for a +particular target, or to configuring GCC to run on a particular host. +Here TARGET and HOST are mnemonics which usually have some relationship +to the canonical system name, but no formal connection. + + If these files do not exist, it means nothing needs to be added for a +given target or host. Most targets need a few `t-TARGET' fragments, +but needing `x-HOST' fragments is rare. + +* Menu: + +* Target Fragment:: Writing `t-TARGET' files. +* Host Fragment:: Writing `x-HOST' files. + + +File: gccint.info, Node: Target Fragment, Next: Host Fragment, Up: Fragments + +19.1 Target Makefile Fragments +============================== + +Target makefile fragments can set these Makefile variables. + +`LIBGCC2_CFLAGS' + Compiler flags to use when compiling `libgcc2.c'. + +`LIB2FUNCS_EXTRA' + A list of source file names to be compiled or assembled and + inserted into `libgcc.a'. + +`Floating Point Emulation' + To have GCC include software floating point libraries in `libgcc.a' + define `FPBIT' and `DPBIT' along with a few rules as follows: + # We want fine grained libraries, so use the new code + # to build the floating point emulation libraries. + FPBIT = fp-bit.c + DPBIT = dp-bit.c + + + fp-bit.c: $(srcdir)/config/fp-bit.c + echo '#define FLOAT' > fp-bit.c + cat $(srcdir)/config/fp-bit.c >> fp-bit.c + + dp-bit.c: $(srcdir)/config/fp-bit.c + cat $(srcdir)/config/fp-bit.c > dp-bit.c + + You may need to provide additional #defines at the beginning of + `fp-bit.c' and `dp-bit.c' to control target endianness and other + options. + +`CRTSTUFF_T_CFLAGS' + Special flags used when compiling `crtstuff.c'. *Note + Initialization::. + +`CRTSTUFF_T_CFLAGS_S' + Special flags used when compiling `crtstuff.c' for shared linking. + Used if you use `crtbeginS.o' and `crtendS.o' in `EXTRA-PARTS'. + *Note Initialization::. + +`MULTILIB_OPTIONS' + For some targets, invoking GCC in different ways produces objects + that can not be linked together. For example, for some targets GCC + produces both big and little endian code. For these targets, you + must arrange for multiple versions of `libgcc.a' to be compiled, + one for each set of incompatible options. When GCC invokes the + linker, it arranges to link in the right version of `libgcc.a', + based on the command line options used. + + The `MULTILIB_OPTIONS' macro lists the set of options for which + special versions of `libgcc.a' must be built. Write options that + are mutually incompatible side by side, separated by a slash. + Write options that may be used together separated by a space. The + build procedure will build all combinations of compatible options. + + For example, if you set `MULTILIB_OPTIONS' to `m68000/m68020 + msoft-float', `Makefile' will build special versions of `libgcc.a' + using the following sets of options: `-m68000', `-m68020', + `-msoft-float', `-m68000 -msoft-float', and `-m68020 -msoft-float'. + +`MULTILIB_DIRNAMES' + If `MULTILIB_OPTIONS' is used, this variable specifies the + directory names that should be used to hold the various libraries. + Write one element in `MULTILIB_DIRNAMES' for each element in + `MULTILIB_OPTIONS'. If `MULTILIB_DIRNAMES' is not used, the + default value will be `MULTILIB_OPTIONS', with all slashes treated + as spaces. + + For example, if `MULTILIB_OPTIONS' is set to `m68000/m68020 + msoft-float', then the default value of `MULTILIB_DIRNAMES' is + `m68000 m68020 msoft-float'. You may specify a different value if + you desire a different set of directory names. + +`MULTILIB_MATCHES' + Sometimes the same option may be written in two different ways. + If an option is listed in `MULTILIB_OPTIONS', GCC needs to know + about any synonyms. In that case, set `MULTILIB_MATCHES' to a + list of items of the form `option=option' to describe all relevant + synonyms. For example, `m68000=mc68000 m68020=mc68020'. + +`MULTILIB_EXCEPTIONS' + Sometimes when there are multiple sets of `MULTILIB_OPTIONS' being + specified, there are combinations that should not be built. In + that case, set `MULTILIB_EXCEPTIONS' to be all of the switch + exceptions in shell case syntax that should not be built. + + For example the ARM processor cannot execute both hardware floating + point instructions and the reduced size THUMB instructions at the + same time, so there is no need to build libraries with both of + these options enabled. Therefore `MULTILIB_EXCEPTIONS' is set to: + *mthumb/*mhard-float* + +`MULTILIB_EXTRA_OPTS' + Sometimes it is desirable that when building multiple versions of + `libgcc.a' certain options should always be passed on to the + compiler. In that case, set `MULTILIB_EXTRA_OPTS' to be the list + of options to be used for all builds. If you set this, you should + probably set `CRTSTUFF_T_CFLAGS' to a dash followed by it. + +`NATIVE_SYSTEM_HEADER_DIR' + If the default location for system headers is not `/usr/include', + you must set this to the directory containing the headers. This + value should match the value of the `SYSTEM_INCLUDE_DIR' macro. + +`SPECS' + Unfortunately, setting `MULTILIB_EXTRA_OPTS' is not enough, since + it does not affect the build of target libraries, at least not the + build of the default multilib. One possible work-around is to use + `DRIVER_SELF_SPECS' to bring options from the `specs' file as if + they had been passed in the compiler driver command line. + However, you don't want to be adding these options after the + toolchain is installed, so you can instead tweak the `specs' file + that will be used during the toolchain build, while you still + install the original, built-in `specs'. The trick is to set + `SPECS' to some other filename (say `specs.install'), that will + then be created out of the built-in specs, and introduce a + `Makefile' rule to generate the `specs' file that's going to be + used at build time out of your `specs.install'. + +`T_CFLAGS' + These are extra flags to pass to the C compiler. They are used + both when building GCC, and when compiling things with the + just-built GCC. This variable is deprecated and should not be + used. + + +File: gccint.info, Node: Host Fragment, Prev: Target Fragment, Up: Fragments + +19.2 Host Makefile Fragments +============================ + +The use of `x-HOST' fragments is discouraged. You should only use it +for makefile dependencies. + + +File: gccint.info, Node: Collect2, Next: Header Dirs, Prev: Fragments, Up: Top + +20 `collect2' +************* + +GCC uses a utility called `collect2' on nearly all systems to arrange +to call various initialization functions at start time. + + The program `collect2' works by linking the program once and looking +through the linker output file for symbols with particular names +indicating they are constructor functions. If it finds any, it creates +a new temporary `.c' file containing a table of them, compiles it, and +links the program a second time including that file. + + The actual calls to the constructors are carried out by a subroutine +called `__main', which is called (automatically) at the beginning of +the body of `main' (provided `main' was compiled with GNU CC). Calling +`__main' is necessary, even when compiling C code, to allow linking C +and C++ object code together. (If you use `-nostdlib', you get an +unresolved reference to `__main', since it's defined in the standard +GCC library. Include `-lgcc' at the end of your compiler command line +to resolve this reference.) + + The program `collect2' is installed as `ld' in the directory where the +passes of the compiler are installed. When `collect2' needs to find +the _real_ `ld', it tries the following file names: + + * a hard coded linker file name, if GCC was configured with the + `--with-ld' option. + + * `real-ld' in the directories listed in the compiler's search + directories. + + * `real-ld' in the directories listed in the environment variable + `PATH'. + + * The file specified in the `REAL_LD_FILE_NAME' configuration macro, + if specified. + + * `ld' in the compiler's search directories, except that `collect2' + will not execute itself recursively. + + * `ld' in `PATH'. + + "The compiler's search directories" means all the directories where +`gcc' searches for passes of the compiler. This includes directories +that you specify with `-B'. + + Cross-compilers search a little differently: + + * `real-ld' in the compiler's search directories. + + * `TARGET-real-ld' in `PATH'. + + * The file specified in the `REAL_LD_FILE_NAME' configuration macro, + if specified. + + * `ld' in the compiler's search directories. + + * `TARGET-ld' in `PATH'. + + `collect2' explicitly avoids running `ld' using the file name under +which `collect2' itself was invoked. In fact, it remembers up a list +of such names--in case one copy of `collect2' finds another copy (or +version) of `collect2' installed as `ld' in a second place in the +search path. + + `collect2' searches for the utilities `nm' and `strip' using the same +algorithm as above for `ld'. + + +File: gccint.info, Node: Header Dirs, Next: Type Information, Prev: Collect2, Up: Top + +21 Standard Header File Directories +*********************************** + +`GCC_INCLUDE_DIR' means the same thing for native and cross. It is +where GCC stores its private include files, and also where GCC stores +the fixed include files. A cross compiled GCC runs `fixincludes' on +the header files in `$(tooldir)/include'. (If the cross compilation +header files need to be fixed, they must be installed before GCC is +built. If the cross compilation header files are already suitable for +GCC, nothing special need be done). + + `GPLUSPLUS_INCLUDE_DIR' means the same thing for native and cross. It +is where `g++' looks first for header files. The C++ library installs +only target independent header files in that directory. + + `LOCAL_INCLUDE_DIR' is used only by native compilers. GCC doesn't +install anything there. It is normally `/usr/local/include'. This is +where local additions to a packaged system should place header files. + + `CROSS_INCLUDE_DIR' is used only by cross compilers. GCC doesn't +install anything there. + + `TOOL_INCLUDE_DIR' is used for both native and cross compilers. It is +the place for other packages to install header files that GCC will use. +For a cross-compiler, this is the equivalent of `/usr/include'. When +you build a cross-compiler, `fixincludes' processes any header files in +this directory. + + +File: gccint.info, Node: Type Information, Next: Plugins, Prev: Header Dirs, Up: Top + +22 Memory Management and Type Information +***************************************** + +GCC uses some fairly sophisticated memory management techniques, which +involve determining information about GCC's data structures from GCC's +source code and using this information to perform garbage collection and +implement precompiled headers. + + A full C parser would be too complicated for this task, so a limited +subset of C is interpreted and special markers are used to determine +what parts of the source to look at. All `struct' and `union' +declarations that define data structures that are allocated under +control of the garbage collector must be marked. All global variables +that hold pointers to garbage-collected memory must also be marked. +Finally, all global variables that need to be saved and restored by a +precompiled header must be marked. (The precompiled header mechanism +can only save static variables if they're scalar. Complex data +structures must be allocated in garbage-collected memory to be saved in +a precompiled header.) + + The full format of a marker is + GTY (([OPTION] [(PARAM)], [OPTION] [(PARAM)] ...)) + but in most cases no options are needed. The outer double parentheses +are still necessary, though: `GTY(())'. Markers can appear: + + * In a structure definition, before the open brace; + + * In a global variable declaration, after the keyword `static' or + `extern'; and + + * In a structure field definition, before the name of the field. + + Here are some examples of marking simple data structures and globals. + + struct GTY(()) TAG + { + FIELDS... + }; + + typedef struct GTY(()) TAG + { + FIELDS... + } *TYPENAME; + + static GTY(()) struct TAG *LIST; /* points to GC memory */ + static GTY(()) int COUNTER; /* save counter in a PCH */ + + The parser understands simple typedefs such as `typedef struct TAG +*NAME;' and `typedef int NAME;'. These don't need to be marked. + +* Menu: + +* GTY Options:: What goes inside a `GTY(())'. +* GGC Roots:: Making global variables GGC roots. +* Files:: How the generated files work. +* Invoking the garbage collector:: How to invoke the garbage collector. +* Troubleshooting:: When something does not work as expected. + + +File: gccint.info, Node: GTY Options, Next: GGC Roots, Up: Type Information + +22.1 The Inside of a `GTY(())' +============================== + +Sometimes the C code is not enough to fully describe the type +structure. Extra information can be provided with `GTY' options and +additional markers. Some options take a parameter, which may be either +a string or a type name, depending on the parameter. If an option +takes no parameter, it is acceptable either to omit the parameter +entirely, or to provide an empty string as a parameter. For example, +`GTY ((skip))' and `GTY ((skip ("")))' are equivalent. + + When the parameter is a string, often it is a fragment of C code. Four +special escapes may be used in these strings, to refer to pieces of the +data structure being marked: + +`%h' + The current structure. + +`%1' + The structure that immediately contains the current structure. + +`%0' + The outermost structure that contains the current structure. + +`%a' + A partial expression of the form `[i1][i2]...' that indexes the + array item currently being marked. + + For instance, suppose that you have a structure of the form + struct A { + ... + }; + struct B { + struct A foo[12]; + }; + and `b' is a variable of type `struct B'. When marking `b.foo[11]', +`%h' would expand to `b.foo[11]', `%0' and `%1' would both expand to +`b', and `%a' would expand to `[11]'. + + As in ordinary C, adjacent strings will be concatenated; this is +helpful when you have a complicated expression. + GTY ((chain_next ("TREE_CODE (&%h.generic) == INTEGER_TYPE" + " ? TYPE_NEXT_VARIANT (&%h.generic)" + " : TREE_CHAIN (&%h.generic)"))) + + The available options are: + +`length ("EXPRESSION")' + There are two places the type machinery will need to be explicitly + told the length of an array. The first case is when a structure + ends in a variable-length array, like this: + struct GTY(()) rtvec_def { + int num_elem; /* number of elements */ + rtx GTY ((length ("%h.num_elem"))) elem[1]; + }; + + In this case, the `length' option is used to override the specified + array length (which should usually be `1'). The parameter of the + option is a fragment of C code that calculates the length. + + The second case is when a structure or a global variable contains a + pointer to an array, like this: + struct gimple_omp_for_iter * GTY((length ("%h.collapse"))) iter; + In this case, `iter' has been allocated by writing something like + x->iter = ggc_alloc_cleared_vec_gimple_omp_for_iter (collapse); + and the `collapse' provides the length of the field. + + This second use of `length' also works on global variables, like: static GTY((length("reg_known_value_size"))) rtx *reg_known_value; + +`skip' + If `skip' is applied to a field, the type machinery will ignore it. + This is somewhat dangerous; the only safe use is in a union when + one field really isn't ever used. + +`desc ("EXPRESSION")' +`tag ("CONSTANT")' +`default' + The type machinery needs to be told which field of a `union' is + currently active. This is done by giving each field a constant + `tag' value, and then specifying a discriminator using `desc'. + The value of the expression given by `desc' is compared against + each `tag' value, each of which should be different. If no `tag' + is matched, the field marked with `default' is used if there is + one, otherwise no field in the union will be marked. + + In the `desc' option, the "current structure" is the union that it + discriminates. Use `%1' to mean the structure containing it. + There are no escapes available to the `tag' option, since it is a + constant. + + For example, + struct GTY(()) tree_binding + { + struct tree_common common; + union tree_binding_u { + tree GTY ((tag ("0"))) scope; + struct cp_binding_level * GTY ((tag ("1"))) level; + } GTY ((desc ("BINDING_HAS_LEVEL_P ((tree)&%0)"))) xscope; + tree value; + }; + + In this example, the value of BINDING_HAS_LEVEL_P when applied to a + `struct tree_binding *' is presumed to be 0 or 1. If 1, the type + mechanism will treat the field `level' as being present and if 0, + will treat the field `scope' as being present. + +`param_is (TYPE)' +`use_param' + Sometimes it's convenient to define some data structure to work on + generic pointers (that is, `PTR') and then use it with a specific + type. `param_is' specifies the real type pointed to, and + `use_param' says where in the generic data structure that type + should be put. + + For instance, to have a `htab_t' that points to trees, one would + write the definition of `htab_t' like this: + typedef struct GTY(()) { + ... + void ** GTY ((use_param, ...)) entries; + ... + } htab_t; + and then declare variables like this: + static htab_t GTY ((param_is (union tree_node))) ict; + +`paramN_is (TYPE)' +`use_paramN' + In more complicated cases, the data structure might need to work on + several different types, which might not necessarily all be + pointers. For this, `param1_is' through `param9_is' may be used to + specify the real type of a field identified by `use_param1' through + `use_param9'. + +`use_params' + When a structure contains another structure that is parameterized, + there's no need to do anything special, the inner structure + inherits the parameters of the outer one. When a structure + contains a pointer to a parameterized structure, the type + machinery won't automatically detect this (it could, it just + doesn't yet), so it's necessary to tell it that the pointed-to + structure should use the same parameters as the outer structure. + This is done by marking the pointer with the `use_params' option. + +`deletable' + `deletable', when applied to a global variable, indicates that when + garbage collection runs, there's no need to mark anything pointed + to by this variable, it can just be set to `NULL' instead. This + is used to keep a list of free structures around for re-use. + +`if_marked ("EXPRESSION")' + Suppose you want some kinds of object to be unique, and so you put + them in a hash table. If garbage collection marks the hash table, + these objects will never be freed, even if the last other + reference to them goes away. GGC has special handling to deal + with this: if you use the `if_marked' option on a global hash + table, GGC will call the routine whose name is the parameter to + the option on each hash table entry. If the routine returns + nonzero, the hash table entry will be marked as usual. If the + routine returns zero, the hash table entry will be deleted. + + The routine `ggc_marked_p' can be used to determine if an element + has been marked already; in fact, the usual case is to use + `if_marked ("ggc_marked_p")'. + +`mark_hook ("HOOK-ROUTINE-NAME")' + If provided for a structure or union type, the given + HOOK-ROUTINE-NAME (between double-quotes) is the name of a routine + called when the garbage collector has just marked the data as + reachable. This routine should not change the data, or call any ggc + routine. Its only argument is a pointer to the just marked (const) + structure or union. + +`maybe_undef' + When applied to a field, `maybe_undef' indicates that it's OK if + the structure that this fields points to is never defined, so long + as this field is always `NULL'. This is used to avoid requiring + backends to define certain optional structures. It doesn't work + with language frontends. + +`nested_ptr (TYPE, "TO EXPRESSION", "FROM EXPRESSION")' + The type machinery expects all pointers to point to the start of an + object. Sometimes for abstraction purposes it's convenient to have + a pointer which points inside an object. So long as it's possible + to convert the original object to and from the pointer, such + pointers can still be used. TYPE is the type of the original + object, the TO EXPRESSION returns the pointer given the original + object, and the FROM EXPRESSION returns the original object given + the pointer. The pointer will be available using the `%h' escape. + +`chain_next ("EXPRESSION")' +`chain_prev ("EXPRESSION")' +`chain_circular ("EXPRESSION")' + It's helpful for the type machinery to know if objects are often + chained together in long lists; this lets it generate code that + uses less stack space by iterating along the list instead of + recursing down it. `chain_next' is an expression for the next + item in the list, `chain_prev' is an expression for the previous + item. For singly linked lists, use only `chain_next'; for doubly + linked lists, use both. The machinery requires that taking the + next item of the previous item gives the original item. + `chain_circular' is similar to `chain_next', but can be used for + circular single linked lists. + +`reorder ("FUNCTION NAME")' + Some data structures depend on the relative ordering of pointers. + If the precompiled header machinery needs to change that ordering, + it will call the function referenced by the `reorder' option, + before changing the pointers in the object that's pointed to by + the field the option applies to. The function must take four + arguments, with the signature + `void *, void *, gt_pointer_operator, void *'. The first + parameter is a pointer to the structure that contains the object + being updated, or the object itself if there is no containing + structure. The second parameter is a cookie that should be + ignored. The third parameter is a routine that, given a pointer, + will update it to its correct new value. The fourth parameter is + a cookie that must be passed to the second parameter. + + PCH cannot handle data structures that depend on the absolute + values of pointers. `reorder' functions can be expensive. When + possible, it is better to depend on properties of the data, like + an ID number or the hash of a string instead. + +`variable_size' + The type machinery expects the types to be of constant size. When + this is not true, for example, with structs that have array fields + or unions, the type machinery cannot tell how many bytes need to + be allocated at each allocation. The `variable_size' is used to + mark such types. The type machinery then provides allocators that + take a parameter indicating an exact size of object being + allocated. Note that the size must be provided in bytes whereas + the `length' option works with array lengths in number of elements. + + For example, + struct GTY((variable_size)) sorted_fields_type { + int len; + tree GTY((length ("%h.len"))) elts[1]; + }; + + Then the objects of `struct sorted_fields_type' are allocated in GC + memory as follows: + field_vec = ggc_alloc_sorted_fields_type (size); + + If FIELD_VEC->ELTS stores N elements, then SIZE could be + calculated as follows: + size_t size = sizeof (struct sorted_fields_type) + n * sizeof (tree); + +`special ("NAME")' + The `special' option is used to mark types that have to be dealt + with by special case machinery. The parameter is the name of the + special case. See `gengtype.c' for further details. Avoid adding + new special cases unless there is no other alternative. + + +File: gccint.info, Node: GGC Roots, Next: Files, Prev: GTY Options, Up: Type Information + +22.2 Marking Roots for the Garbage Collector +============================================ + +In addition to keeping track of types, the type machinery also locates +the global variables ("roots") that the garbage collector starts at. +Roots must be declared using one of the following syntaxes: + + * `extern GTY(([OPTIONS])) TYPE NAME;' + + * `static GTY(([OPTIONS])) TYPE NAME;' + The syntax + * `GTY(([OPTIONS])) TYPE NAME;' + is _not_ accepted. There should be an `extern' declaration of such a +variable in a header somewhere--mark that, not the definition. Or, if +the variable is only used in one file, make it `static'. + + +File: gccint.info, Node: Files, Next: Invoking the garbage collector, Prev: GGC Roots, Up: Type Information + +22.3 Source Files Containing Type Information +============================================= + +Whenever you add `GTY' markers to a source file that previously had +none, or create a new source file containing `GTY' markers, there are +three things you need to do: + + 1. You need to add the file to the list of source files the type + machinery scans. There are four cases: + + a. For a back-end file, this is usually done automatically; if + not, you should add it to `target_gtfiles' in the appropriate + port's entries in `config.gcc'. + + b. For files shared by all front ends, add the filename to the + `GTFILES' variable in `Makefile.in'. + + c. For files that are part of one front end, add the filename to + the `gtfiles' variable defined in the appropriate + `config-lang.in'. For C, the file is `c-config-lang.in'. + Headers should appear before non-headers in this list. + + d. For files that are part of some but not all front ends, add + the filename to the `gtfiles' variable of _all_ the front ends + that use it. + + 2. If the file was a header file, you'll need to check that it's + included in the right place to be visible to the generated files. + For a back-end header file, this should be done automatically. + For a front-end header file, it needs to be included by the same + file that includes `gtype-LANG.h'. For other header files, it + needs to be included in `gtype-desc.c', which is a generated file, + so add it to `ifiles' in `open_base_file' in `gengtype.c'. + + For source files that aren't header files, the machinery will + generate a header file that should be included in the source file + you just changed. The file will be called `gt-PATH.h' where PATH + is the pathname relative to the `gcc' directory with slashes + replaced by -, so for example the header file to be included in + `cp/parser.c' is called `gt-cp-parser.c'. The generated header + file should be included after everything else in the source file. + Don't forget to mention this file as a dependency in the + `Makefile'! + + + For language frontends, there is another file that needs to be included +somewhere. It will be called `gtype-LANG.h', where LANG is the name of +the subdirectory the language is contained in. + + Plugins can add additional root tables. Run the `gengtype' utility in +plugin mode as `gengtype -P pluginout.h SOURCE-DIR FILE-LIST PLUGIN*.C' +with your plugin files PLUGIN*.C using `GTY' to generate the +PLUGINOUT.H file. The GCC build tree is needed to be present in that +mode. + + +File: gccint.info, Node: Invoking the garbage collector, Next: Troubleshooting, Prev: Files, Up: Type Information + +22.4 How to invoke the garbage collector +======================================== + +The GCC garbage collector GGC is only invoked explicitly. In contrast +with many other garbage collectors, it is not implicitly invoked by +allocation routines when a lot of memory has been consumed. So the only +way to have GGC reclaim storage it to call the `ggc_collect' function +explicitly. This call is an expensive operation, as it may have to +scan the entire heap. Beware that local variables (on the GCC call +stack) are not followed by such an invocation (as many other garbage +collectors do): you should reference all your data from static or +external `GTY'-ed variables, and it is advised to call `ggc_collect' +with a shallow call stack. The GGC is an exact mark and sweep garbage +collector (so it does not scan the call stack for pointers). In +practice GCC passes don't often call `ggc_collect' themselves, because +it is called by the pass manager between passes. + + At the time of the `ggc_collect' call all pointers in the GC-marked +structures must be valid or `NULL'. In practice this means that there +should not be uninitialized pointer fields in the structures even if +your code never reads or writes those fields at a particular instance. +One way to ensure this is to use cleared versions of allocators unless +all the fields are initialized manually immediately after allocation. + + +File: gccint.info, Node: Troubleshooting, Prev: Invoking the garbage collector, Up: Type Information + +22.5 Troubleshooting the garbage collector +========================================== + +With the current garbage collector implementation, most issues should +show up as GCC compilation errors. Some of the most commonly +encountered issues are described below. + + * Gengtype does not produce allocators for a `GTY'-marked type. + Gengtype checks if there is at least one possible path from GC + roots to at least one instance of each type before outputting + allocators. If there is no such path, the `GTY' markers will be + ignored and no allocators will be output. Solve this by making + sure that there exists at least one such path. If creating it is + unfeasible or raises a "code smell", consider if you really must + use GC for allocating such type. + + * Link-time errors about undefined `gt_ggc_r_foo_bar' and + similarly-named symbols. Check if your `foo_bar' source file has + `#include "gt-foo_bar.h"' as its very last line. + + + +File: gccint.info, Node: Plugins, Next: LTO, Prev: Type Information, Up: Top + +23 Plugins +********** + +23.1 Loading Plugins +==================== + +Plugins are supported on platforms that support `-ldl -rdynamic'. They +are loaded by the compiler using `dlopen' and invoked at pre-determined +locations in the compilation process. + + Plugins are loaded with + + `-fplugin=/path/to/NAME.so' `-fplugin-arg-NAME-KEY1[=VALUE1]' + + The plugin arguments are parsed by GCC and passed to respective +plugins as key-value pairs. Multiple plugins can be invoked by +specifying multiple `-fplugin' arguments. + + A plugin can be simply given by its short name (no dots or slashes). +When simply passing `-fplugin=NAME', the plugin is loaded from the +`plugin' directory, so `-fplugin=NAME' is the same as `-fplugin=`gcc +-print-file-name=plugin`/NAME.so', using backquote shell syntax to +query the `plugin' directory. + +23.2 Plugin API +=============== + +Plugins are activated by the compiler at specific events as defined in +`gcc-plugin.h'. For each event of interest, the plugin should call +`register_callback' specifying the name of the event and address of the +callback function that will handle that event. + + The header `gcc-plugin.h' must be the first gcc header to be included. + +23.2.1 Plugin license check +--------------------------- + +Every plugin should define the global symbol `plugin_is_GPL_compatible' +to assert that it has been licensed under a GPL-compatible license. If +this symbol does not exist, the compiler will emit a fatal error and +exit with the error message: + + fatal error: plugin NAME is not licensed under a GPL-compatible license + NAME: undefined symbol: plugin_is_GPL_compatible + compilation terminated + + The declared type of the symbol should be int, to match a forward +declaration in `gcc-plugin.h' that suppresses C++ mangling. It does +not need to be in any allocated section, though. The compiler merely +asserts that the symbol exists in the global scope. Something like +this is enough: + + int plugin_is_GPL_compatible; + +23.2.2 Plugin initialization +---------------------------- + +Every plugin should export a function called `plugin_init' that is +called right after the plugin is loaded. This function is responsible +for registering all the callbacks required by the plugin and do any +other required initialization. + + This function is called from `compile_file' right before invoking the +parser. The arguments to `plugin_init' are: + + * `plugin_info': Plugin invocation information. + + * `version': GCC version. + + The `plugin_info' struct is defined as follows: + + struct plugin_name_args + { + char *base_name; /* Short name of the plugin + (filename without .so suffix). */ + const char *full_name; /* Path to the plugin as specified with + -fplugin=. */ + int argc; /* Number of arguments specified with + -fplugin-arg-.... */ + struct plugin_argument *argv; /* Array of ARGC key-value pairs. */ + const char *version; /* Version string provided by plugin. */ + const char *help; /* Help string provided by plugin. */ + } + + If initialization fails, `plugin_init' must return a non-zero value. +Otherwise, it should return 0. + + The version of the GCC compiler loading the plugin is described by the +following structure: + + struct plugin_gcc_version + { + const char *basever; + const char *datestamp; + const char *devphase; + const char *revision; + const char *configuration_arguments; + }; + + The function `plugin_default_version_check' takes two pointers to such +structure and compare them field by field. It can be used by the +plugin's `plugin_init' function. + + The version of GCC used to compile the plugin can be found in the +symbol `gcc_version' defined in the header `plugin-version.h'. The +recommended version check to perform looks like + + #include "plugin-version.h" + ... + + int + plugin_init (struct plugin_name_args *plugin_info, + struct plugin_gcc_version *version) + { + if (!plugin_default_version_check (version, &gcc_version)) + return 1; + + } + + but you can also check the individual fields if you want a less strict +check. + +23.2.3 Plugin callbacks +----------------------- + +Callback functions have the following prototype: + + /* The prototype for a plugin callback function. + gcc_data - event-specific data provided by GCC + user_data - plugin-specific data provided by the plug-in. */ + typedef void (*plugin_callback_func)(void *gcc_data, void *user_data); + + Callbacks can be invoked at the following pre-determined events: + + enum plugin_event + { + PLUGIN_PASS_MANAGER_SETUP, /* To hook into pass manager. */ + PLUGIN_FINISH_TYPE, /* After finishing parsing a type. */ + PLUGIN_FINISH_UNIT, /* Useful for summary processing. */ + PLUGIN_PRE_GENERICIZE, /* Allows to see low level AST in C and C++ frontends. */ + PLUGIN_FINISH, /* Called before GCC exits. */ + PLUGIN_INFO, /* Information about the plugin. */ + PLUGIN_GGC_START, /* Called at start of GCC Garbage Collection. */ + PLUGIN_GGC_MARKING, /* Extend the GGC marking. */ + PLUGIN_GGC_END, /* Called at end of GGC. */ + PLUGIN_REGISTER_GGC_ROOTS, /* Register an extra GGC root table. */ + PLUGIN_REGISTER_GGC_CACHES, /* Register an extra GGC cache table. */ + PLUGIN_ATTRIBUTES, /* Called during attribute registration */ + PLUGIN_START_UNIT, /* Called before processing a translation unit. */ + PLUGIN_PRAGMAS, /* Called during pragma registration. */ + /* Called before first pass from all_passes. */ + PLUGIN_ALL_PASSES_START, + /* Called after last pass from all_passes. */ + PLUGIN_ALL_PASSES_END, + /* Called before first ipa pass. */ + PLUGIN_ALL_IPA_PASSES_START, + /* Called after last ipa pass. */ + PLUGIN_ALL_IPA_PASSES_END, + /* Allows to override pass gate decision for current_pass. */ + PLUGIN_OVERRIDE_GATE, + /* Called before executing a pass. */ + PLUGIN_PASS_EXECUTION, + /* Called before executing subpasses of a GIMPLE_PASS in + execute_ipa_pass_list. */ + PLUGIN_EARLY_GIMPLE_PASSES_START, + /* Called after executing subpasses of a GIMPLE_PASS in + execute_ipa_pass_list. */ + PLUGIN_EARLY_GIMPLE_PASSES_END, + /* Called when a pass is first instantiated. */ + PLUGIN_NEW_PASS, + + PLUGIN_EVENT_FIRST_DYNAMIC /* Dummy event used for indexing callback + array. */ + }; + + In addition, plugins can also look up the enumerator of a named event, +and / or generate new events dynamically, by calling the function +`get_named_event_id'. + + To register a callback, the plugin calls `register_callback' with the +arguments: + + * `char *name': Plugin name. + + * `int event': The event code. + + * `plugin_callback_func callback': The function that handles `event'. + + * `void *user_data': Pointer to plugin-specific data. + + For the PLUGIN_PASS_MANAGER_SETUP, PLUGIN_INFO, +PLUGIN_REGISTER_GGC_ROOTS and PLUGIN_REGISTER_GGC_CACHES pseudo-events +the `callback' should be null, and the `user_data' is specific. + + When the PLUGIN_PRAGMAS event is triggered (with a null pointer as +data from GCC), plugins may register their own pragmas using functions +like `c_register_pragma' or `c_register_pragma_with_expansion'. + +23.3 Interacting with the pass manager +====================================== + +There needs to be a way to add/reorder/remove passes dynamically. This +is useful for both analysis plugins (plugging in after a certain pass +such as CFG or an IPA pass) and optimization plugins. + + Basic support for inserting new passes or replacing existing passes is +provided. A plugin registers a new pass with GCC by calling +`register_callback' with the `PLUGIN_PASS_MANAGER_SETUP' event and a +pointer to a `struct register_pass_info' object defined as follows + + enum pass_positioning_ops + { + PASS_POS_INSERT_AFTER, // Insert after the reference pass. + PASS_POS_INSERT_BEFORE, // Insert before the reference pass. + PASS_POS_REPLACE // Replace the reference pass. + }; + + struct register_pass_info + { + struct opt_pass *pass; /* New pass provided by the plugin. */ + const char *reference_pass_name; /* Name of the reference pass for hooking + up the new pass. */ + int ref_pass_instance_number; /* Insert the pass at the specified + instance number of the reference pass. */ + /* Do it for every instance if it is 0. */ + enum pass_positioning_ops pos_op; /* how to insert the new pass. */ + }; + + + /* Sample plugin code that registers a new pass. */ + int + plugin_init (struct plugin_name_args *plugin_info, + struct plugin_gcc_version *version) + { + struct register_pass_info pass_info; + + ... + + /* Code to fill in the pass_info object with new pass information. */ + + ... + + /* Register the new pass. */ + register_callback (plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &pass_info); + + ... + } + +23.4 Interacting with the GCC Garbage Collector +=============================================== + +Some plugins may want to be informed when GGC (the GCC Garbage +Collector) is running. They can register callbacks for the +`PLUGIN_GGC_START' and `PLUGIN_GGC_END' events (for which the callback +is called with a null `gcc_data') to be notified of the start or end of +the GCC garbage collection. + + Some plugins may need to have GGC mark additional data. This can be +done by registering a callback (called with a null `gcc_data') for the +`PLUGIN_GGC_MARKING' event. Such callbacks can call the `ggc_set_mark' +routine, preferably thru the `ggc_mark' macro (and conversely, these +routines should usually not be used in plugins outside of the +`PLUGIN_GGC_MARKING' event). + + Some plugins may need to add extra GGC root tables, e.g. to handle +their own `GTY'-ed data. This can be done with the +`PLUGIN_REGISTER_GGC_ROOTS' pseudo-event with a null callback and the +extra root table (of type `struct ggc_root_tab*') as `user_data'. +Plugins that want to use the `if_marked' hash table option can add the +extra GGC cache tables generated by `gengtype' using the +`PLUGIN_REGISTER_GGC_CACHES' pseudo-event with a null callback and the +extra cache table (of type `struct ggc_cache_tab*') as `user_data'. +Running the `gengtype -p SOURCE-DIR FILE-LIST PLUGIN*.C ...' utility +generates these extra root tables. + + You should understand the details of memory management inside GCC +before using `PLUGIN_GGC_MARKING', `PLUGIN_REGISTER_GGC_ROOTS' or +`PLUGIN_REGISTER_GGC_CACHES'. + +23.5 Giving information about a plugin +====================================== + +A plugin should give some information to the user about itself. This +uses the following structure: + + struct plugin_info + { + const char *version; + const char *help; + }; + + Such a structure is passed as the `user_data' by the plugin's init +routine using `register_callback' with the `PLUGIN_INFO' pseudo-event +and a null callback. + +23.6 Registering custom attributes or pragmas +============================================= + +For analysis (or other) purposes it is useful to be able to add custom +attributes or pragmas. + + The `PLUGIN_ATTRIBUTES' callback is called during attribute +registration. Use the `register_attribute' function to register custom +attributes. + + /* Attribute handler callback */ + static tree + handle_user_attribute (tree *node, tree name, tree args, + int flags, bool *no_add_attrs) + { + return NULL_TREE; + } + + /* Attribute definition */ + static struct attribute_spec user_attr = + { "user", 1, 1, false, false, false, handle_user_attribute }; + + /* Plugin callback called during attribute registration. + Registered with register_callback (plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL) + */ + static void + register_attributes (void *event_data, void *data) + { + warning (0, G_("Callback to register attributes")); + register_attribute (&user_attr); + } + + The `PLUGIN_PRAGMAS' callback is called during pragmas registration. +Use the `c_register_pragma' or `c_register_pragma_with_expansion' +functions to register custom pragmas. + + /* Plugin callback called during pragmas registration. Registered with + register_callback (plugin_name, PLUGIN_PRAGMAS, + register_my_pragma, NULL); + */ + static void + register_my_pragma (void *event_data, void *data) + { + warning (0, G_("Callback to register pragmas")); + c_register_pragma ("GCCPLUGIN", "sayhello", handle_pragma_sayhello); + } + + It is suggested to pass `"GCCPLUGIN"' (or a short name identifying +your plugin) as the "space" argument of your pragma. + +23.7 Recording information about pass execution +=============================================== + +The event PLUGIN_PASS_EXECUTION passes the pointer to the executed pass +(the same as current_pass) as `gcc_data' to the callback. You can also +inspect cfun to find out about which function this pass is executed for. +Note that this event will only be invoked if the gate check (if +applicable, modified by PLUGIN_OVERRIDE_GATE) succeeds. You can use +other hooks, like `PLUGIN_ALL_PASSES_START', `PLUGIN_ALL_PASSES_END', +`PLUGIN_ALL_IPA_PASSES_START', `PLUGIN_ALL_IPA_PASSES_END', +`PLUGIN_EARLY_GIMPLE_PASSES_START', and/or +`PLUGIN_EARLY_GIMPLE_PASSES_END' to manipulate global state in your +plugin(s) in order to get context for the pass execution. + +23.8 Controlling which passes are being run +=========================================== + +After the original gate function for a pass is called, its result - the +gate status - is stored as an integer. Then the event +`PLUGIN_OVERRIDE_GATE' is invoked, with a pointer to the gate status in +the `gcc_data' parameter to the callback function. A nonzero value of +the gate status means that the pass is to be executed. You can both +read and write the gate status via the passed pointer. + +23.9 Keeping track of available passes +====================================== + +When your plugin is loaded, you can inspect the various pass lists to +determine what passes are available. However, other plugins might add +new passes. Also, future changes to GCC might cause generic passes to +be added after plugin loading. When a pass is first added to one of +the pass lists, the event `PLUGIN_NEW_PASS' is invoked, with the +callback parameter `gcc_data' pointing to the new pass. + +23.10 Building GCC plugins +========================== + +If plugins are enabled, GCC installs the headers needed to build a +plugin (somewhere in the installation tree, e.g. under `/usr/local'). +In particular a `plugin/include' directory is installed, containing all +the header files needed to build plugins. + + On most systems, you can query this `plugin' directory by invoking +`gcc -print-file-name=plugin' (replace if needed `gcc' with the +appropriate program path). + + Inside plugins, this `plugin' directory name can be queried by calling +`default_plugin_dir_name ()'. + + The following GNU Makefile excerpt shows how to build a simple plugin: + + GCC=gcc + PLUGIN_SOURCE_FILES= plugin1.c plugin2.c + PLUGIN_OBJECT_FILES= $(patsubst %.c,%.o,$(PLUGIN_SOURCE_FILES)) + GCCPLUGINS_DIR:= $(shell $(GCC) -print-file-name=plugin) + CFLAGS+= -I$(GCCPLUGINS_DIR)/include -fPIC -O2 + + plugin.so: $(PLUGIN_OBJECT_FILES) + $(GCC) -shared $^ -o $@ + + A single source file plugin may be built with `gcc -I`gcc +-print-file-name=plugin`/include -fPIC -shared -O2 plugin.c -o +plugin.so', using backquote shell syntax to query the `plugin' +directory. + + Plugins needing to use `gengtype' require a GCC build directory for +the same version of GCC that they will be linked against. + + +File: gccint.info, Node: LTO, Next: Funding, Prev: Plugins, Up: Top + +24 Link Time Optimization +************************* + +24.1 Design Overview +==================== + +Link time optimization is implemented as a GCC front end for a bytecode +representation of GIMPLE that is emitted in special sections of `.o' +files. Currently, LTO support is enabled in most ELF-based systems, as +well as darwin, cygwin and mingw systems. + + Since GIMPLE bytecode is saved alongside final object code, object +files generated with LTO support are larger than regular object files. +This "fat" object format makes it easy to integrate LTO into existing +build systems, as one can, for instance, produce archives of the files. +Additionally, one might be able to ship one set of fat objects which +could be used both for development and the production of optimized +builds. A, perhaps surprising, side effect of this feature is that any +mistake in the toolchain that leads to LTO information not being used +(e.g. an older `libtool' calling `ld' directly). This is both an +advantage, as the system is more robust, and a disadvantage, as the +user is not informed that the optimization has been disabled. + + The current implementation only produces "fat" objects, effectively +doubling compilation time and increasing file sizes up to 5x the +original size. This hides the problem that some tools, such as `ar' +and `nm', need to understand symbol tables of LTO sections. These +tools were extended to use the plugin infrastructure, and with these +problems solved, GCC will also support "slim" objects consisting of the +intermediate code alone. + + At the highest level, LTO splits the compiler in two. The first half +(the "writer") produces a streaming representation of all the internal +data structures needed to optimize and generate code. This includes +declarations, types, the callgraph and the GIMPLE representation of +function bodies. + + When `-flto' is given during compilation of a source file, the pass +manager executes all the passes in `all_lto_gen_passes'. Currently, +this phase is composed of two IPA passes: + + * `pass_ipa_lto_gimple_out' This pass executes the function + `lto_output' in `lto-streamer-out.c', which traverses the call + graph encoding every reachable declaration, type and function. + This generates a memory representation of all the file sections + described below. + + * `pass_ipa_lto_finish_out' This pass executes the function + `produce_asm_for_decls' in `lto-streamer-out.c', which takes the + memory image built in the previous pass and encodes it in the + corresponding ELF file sections. + + The second half of LTO support is the "reader". This is implemented +as the GCC front end `lto1' in `lto/lto.c'. When `collect2' detects a +link set of `.o'/`.a' files with LTO information and the `-flto' is +enabled, it invokes `lto1' which reads the set of files and aggregates +them into a single translation unit for optimization. The main entry +point for the reader is `lto/lto.c':`lto_main'. + +24.1.1 LTO modes of operation +----------------------------- + +One of the main goals of the GCC link-time infrastructure was to allow +effective compilation of large programs. For this reason GCC +implements two link-time compilation modes. + + 1. _LTO mode_, in which the whole program is read into the compiler + at link-time and optimized in a similar way as if it were a single + source-level compilation unit. + + 2. _WHOPR or partitioned mode_, designed to utilize multiple CPUs + and/or a distributed compilation environment to quickly link large + applications. WHOPR stands for WHOle Program optimizeR (not to be + confused with the semantics of `-fwhole-program'). It partitions + the aggregated callgraph from many different `.o' files and + distributes the compilation of the sub-graphs to different CPUs. + + Note that distributed compilation is not implemented yet, but since + the parallelism is facilitated via generating a `Makefile', it + would be easy to implement. + + WHOPR splits LTO into three main stages: + 1. Local generation (LGEN) This stage executes in parallel. Every + file in the program is compiled into the intermediate language and + packaged together with the local call-graph and summary + information. This stage is the same for both the LTO and WHOPR + compilation mode. + + 2. Whole Program Analysis (WPA) WPA is performed sequentially. The + global call-graph is generated, and a global analysis procedure + makes transformation decisions. The global call-graph is + partitioned to facilitate parallel optimization during phase 3. + The results of the WPA stage are stored into new object files + which contain the partitions of program expressed in the + intermediate language and the optimization decisions. + + 3. Local transformations (LTRANS) This stage executes in parallel. + All the decisions made during phase 2 are implemented locally in + each partitioned object file, and the final object code is + generated. Optimizations which cannot be decided efficiently + during the phase 2 may be performed on the local call-graph + partitions. + + WHOPR can be seen as an extension of the usual LTO mode of +compilation. In LTO, WPA and LTRANS are executed within a single +execution of the compiler, after the whole program has been read into +memory. + + When compiling in WHOPR mode, the callgraph is partitioned during the +WPA stage. The whole program is split into a given number of +partitions of roughly the same size. The compiler tries to minimize +the number of references which cross partition boundaries. The main +advantage of WHOPR is to allow the parallel execution of LTRANS stages, +which are the most time-consuming part of the compilation process. +Additionally, it avoids the need to load the whole program into memory. + +24.2 LTO file sections +====================== + +LTO information is stored in several ELF sections inside object files. +Data structures and enum codes for sections are defined in +`lto-streamer.h'. + + These sections are emitted from `lto-streamer-out.c' and mapped in all +at once from `lto/lto.c':`lto_file_read'. The individual functions +dealing with the reading/writing of each section are described below. + + * Command line options (`.gnu.lto_.opts') + + This section contains the command line options used to generate the + object files. This is used at link time to determine the + optimization level and other settings when they are not explicitly + specified at the linker command line. + + Currently, GCC does not support combining LTO object files compiled + with different set of the command line options into a single + binary. At link time, the options given on the command line and + the options saved on all the files in a link-time set are applied + globally. No attempt is made at validating the combination of + flags (other than the usual validation done by option processing). + This is implemented in `lto/lto.c':`lto_read_all_file_options'. + + * Symbol table (`.gnu.lto_.symtab') + + This table replaces the ELF symbol table for functions and + variables represented in the LTO IL. Symbols used and exported by + the optimized assembly code of "fat" objects might not match the + ones used and exported by the intermediate code. This table is + necessary because the intermediate code is less optimized and thus + requires a separate symbol table. + + Additionally, the binary code in the "fat" object will lack a call + to a function, since the call was optimized out at compilation time + after the intermediate language was streamed out. In some special + cases, the same optimization may not happen during link-time + optimization. This would lead to an undefined symbol if only one + symbol table was used. + + The symbol table is emitted in + `lto-streamer-out.c':`produce_symtab'. + + * Global declarations and types (`.gnu.lto_.decls') + + This section contains an intermediate language dump of all + declarations and types required to represent the callgraph, static + variables and top-level debug info. + + The contents of this section are emitted in + `lto-streamer-out.c':`produce_asm_for_decls'. Types and symbols + are emitted in a topological order that preserves the sharing of + pointers when the file is read back in + (`lto.c':`read_cgraph_and_symbols'). + + * The callgraph (`.gnu.lto_.cgraph') + + This section contains the basic data structure used by the GCC + inter-procedural optimization infrastructure. This section stores + an annotated multi-graph which represents the functions and call + sites as well as the variables, aliases and top-level `asm' + statements. + + This section is emitted in `lto-streamer-out.c':`output_cgraph' + and read in `lto-cgraph.c':`input_cgraph'. + + * IPA references (`.gnu.lto_.refs') + + This section contains references between function and static + variables. It is emitted by `lto-cgraph.c':`output_refs' and read + by `lto-cgraph.c':`input_refs'. + + * Function bodies (`.gnu.lto_.function_body.<name>') + + This section contains function bodies in the intermediate language + representation. Every function body is in a separate section to + allow copying of the section independently to different object + files or reading the function on demand. + + Functions are emitted in `lto-streamer-out.c':`output_function' + and read in `lto-streamer-in.c':`input_function'. + + * Static variable initializers (`.gnu.lto_.vars') + + This section contains all the symbols in the global variable pool. + It is emitted by `lto-cgraph.c':`output_varpool' and read in + `lto-cgraph.c':`input_cgraph'. + + * Summaries and optimization summaries used by IPA passes + (`.gnu.lto_.<xxx>', where `<xxx>' is one of `jmpfuncs', + `pureconst' or `reference') + + These sections are used by IPA passes that need to emit summary + information during LTO generation to be read and aggregated at + link time. Each pass is responsible for implementing two pass + manager hooks: one for writing the summary and another for reading + it in. The format of these sections is entirely up to each + individual pass. The only requirement is that the writer and + reader hooks agree on the format. + +24.3 Using summary information in IPA passes +============================================ + +Programs are represented internally as a _callgraph_ (a multi-graph +where nodes are functions and edges are call sites) and a _varpool_ (a +list of static and external variables in the program). + + The inter-procedural optimization is organized as a sequence of +individual passes, which operate on the callgraph and the varpool. To +make the implementation of WHOPR possible, every inter-procedural +optimization pass is split into several stages that are executed at +different times during WHOPR compilation: + + * LGEN time + 1. _Generate summary_ (`generate_summary' in `struct + ipa_opt_pass_d'). This stage analyzes every function body + and variable initializer is examined and stores relevant + information into a pass-specific data structure. + + 2. _Write summary_ (`write_summary' in `struct ipa_opt_pass_d'). + This stage writes all the pass-specific information generated + by `generate_summary'. Summaries go into their own + `LTO_section_*' sections that have to be declared in + `lto-streamer.h':`enum lto_section_type'. A new section is + created by calling `create_output_block' and data can be + written using the `lto_output_*' routines. + + * WPA time + 1. _Read summary_ (`read_summary' in `struct ipa_opt_pass_d'). + This stage reads all the pass-specific information in exactly + the same order that it was written by `write_summary'. + + 2. _Execute_ (`execute' in `struct opt_pass'). This performs + inter-procedural propagation. This must be done without + actual access to the individual function bodies or variable + initializers. Typically, this results in a transitive + closure operation over the summary information of all the + nodes in the callgraph. + + 3. _Write optimization summary_ (`write_optimization_summary' in + `struct ipa_opt_pass_d'). This writes the result of the + inter-procedural propagation into the object file. This can + use the same data structures and helper routines used in + `write_summary'. + + * LTRANS time + 1. _Read optimization summary_ (`read_optimization_summary' in + `struct ipa_opt_pass_d'). The counterpart to + `write_optimization_summary'. This reads the interprocedural + optimization decisions in exactly the same format emitted by + `write_optimization_summary'. + + 2. _Transform_ (`function_transform' and `variable_transform' in + `struct ipa_opt_pass_d'). The actual function bodies and + variable initializers are updated based on the information + passed down from the _Execute_ stage. + + The implementation of the inter-procedural passes are shared between +LTO, WHOPR and classic non-LTO compilation. + + * During the traditional file-by-file mode every pass executes its + own _Generate summary_, _Execute_, and _Transform_ stages within + the single execution context of the compiler. + + * In LTO compilation mode, every pass uses _Generate summary_ and + _Write summary_ stages at compilation time, while the _Read + summary_, _Execute_, and _Transform_ stages are executed at link + time. + + * In WHOPR mode all stages are used. + + To simplify development, the GCC pass manager differentiates between +normal inter-procedural passes and small inter-procedural passes. A +_small inter-procedural pass_ (`SIMPLE_IPA_PASS') is a pass that does +everything at once and thus it can not be executed during WPA in WHOPR +mode. It defines only the _Execute_ stage and during this stage it +accesses and modifies the function bodies. Such passes are useful for +optimization at LGEN or LTRANS time and are used, for example, to +implement early optimization before writing object files. The simple +inter-procedural passes can also be used for easier prototyping and +development of a new inter-procedural pass. + +24.3.1 Virtual clones +--------------------- + +One of the main challenges of introducing the WHOPR compilation mode +was addressing the interactions between optimization passes. In LTO +compilation mode, the passes are executed in a sequence, each of which +consists of analysis (or _Generate summary_), propagation (or +_Execute_) and _Transform_ stages. Once the work of one pass is +finished, the next pass sees the updated program representation and can +execute. This makes the individual passes dependent on each other. + + In WHOPR mode all passes first execute their _Generate summary_ stage. +Then summary writing marks the end of the LGEN stage. At WPA time, the +summaries are read back into memory and all passes run the _Execute_ +stage. Optimization summaries are streamed and sent to LTRANS, where +all the passes execute the _Transform_ stage. + + Most optimization passes split naturally into analysis, propagation +and transformation stages. But some do not. The main problem arises +when one pass performs changes and the following pass gets confused by +seeing different callgraphs between the _Transform_ stage and the +_Generate summary_ or _Execute_ stage. This means that the passes are +required to communicate their decisions with each other. + + To facilitate this communication, the GCC callgraph infrastructure +implements _virtual clones_, a method of representing the changes +performed by the optimization passes in the callgraph without needing +to update function bodies. + + A _virtual clone_ in the callgraph is a function that has no +associated body, just a description of how to create its body based on +a different function (which itself may be a virtual clone). + + The description of function modifications includes adjustments to the +function's signature (which allows, for example, removing or adding +function arguments), substitutions to perform on the function body, +and, for inlined functions, a pointer to the function that it will be +inlined into. + + It is also possible to redirect any edge of the callgraph from a +function to its virtual clone. This implies updating of the call site +to adjust for the new function signature. + + Most of the transformations performed by inter-procedural +optimizations can be represented via virtual clones. For instance, a +constant propagation pass can produce a virtual clone of the function +which replaces one of its arguments by a constant. The inliner can +represent its decisions by producing a clone of a function whose body +will be later integrated into a given function. + + Using _virtual clones_, the program can be easily updated during the +_Execute_ stage, solving most of pass interactions problems that would +otherwise occur during _Transform_. + + Virtual clones are later materialized in the LTRANS stage and turned +into real functions. Passes executed after the virtual clone were +introduced also perform their _Transform_ stage on new functions, so +for a pass there is no significant difference between operating on a +real function or a virtual clone introduced before its _Execute_ stage. + + Optimization passes then work on virtual clones introduced before +their _Execute_ stage as if they were real functions. The only +difference is that clones are not visible during the _Generate Summary_ +stage. + + To keep function summaries updated, the callgraph interface allows an +optimizer to register a callback that is called every time a new clone +is introduced as well as when the actual function or variable is +generated or when a function or variable is removed. These hooks are +registered in the _Generate summary_ stage and allow the pass to keep +its information intact until the _Execute_ stage. The same hooks can +also be registered during the _Execute_ stage to keep the optimization +summaries updated for the _Transform_ stage. + +24.3.2 IPA references +--------------------- + +GCC represents IPA references in the callgraph. For a function or +variable `A', the _IPA reference_ is a list of all locations where the +address of `A' is taken and, when `A' is a variable, a list of all +direct stores and reads to/from `A'. References represent an oriented +multi-graph on the union of nodes of the callgraph and the varpool. See +`ipa-reference.c':`ipa_reference_write_optimization_summary' and +`ipa-reference.c':`ipa_reference_read_optimization_summary' for details. + +24.3.3 Jump functions +--------------------- + +Suppose that an optimization pass sees a function `A' and it knows the +values of (some of) its arguments. The _jump function_ describes the +value of a parameter of a given function call in function `A' based on +this knowledge. + + Jump functions are used by several optimizations, such as the +inter-procedural constant propagation pass and the devirtualization +pass. The inliner also uses jump functions to perform inlining of +callbacks. + +24.4 Whole program assumptions, linker plugin and symbol visibilities +===================================================================== + +Link-time optimization gives relatively minor benefits when used alone. +The problem is that propagation of inter-procedural information does +not work well across functions and variables that are called or +referenced by other compilation units (such as from a dynamically +linked library). We say that such functions are variables are +_externally visible_. + + To make the situation even more difficult, many applications organize +themselves as a set of shared libraries, and the default ELF visibility +rules allow one to overwrite any externally visible symbol with a +different symbol at runtime. This basically disables any optimizations +across such functions and variables, because the compiler cannot be +sure that the function body it is seeing is the same function body that +will be used at runtime. Any function or variable not declared +`static' in the sources degrades the quality of inter-procedural +optimization. + + To avoid this problem the compiler must assume that it sees the whole +program when doing link-time optimization. Strictly speaking, the +whole program is rarely visible even at link-time. Standard system +libraries are usually linked dynamically or not provided with the +link-time information. In GCC, the whole program option +(`-fwhole-program') asserts that every function and variable defined in +the current compilation unit is static, except for function `main' +(note: at link time, the current unit is the union of all objects +compiled with LTO). Since some functions and variables need to be +referenced externally, for example by another DSO or from an assembler +file, GCC also provides the function and variable attribute +`externally_visible' which can be used to disable the effect of +`-fwhole-program' on a specific symbol. + + The whole program mode assumptions are slightly more complex in C++, +where inline functions in headers are put into _COMDAT_ sections. +COMDAT function and variables can be defined by multiple object files +and their bodies are unified at link-time and dynamic link-time. +COMDAT functions are changed to local only when their address is not +taken and thus un-sharing them with a library is not harmful. COMDAT +variables always remain externally visible, however for readonly +variables it is assumed that their initializers cannot be overwritten +by a different value. + + GCC provides the function and variable attribute `visibility' that can +be used to specify the visibility of externally visible symbols (or +alternatively an `-fdefault-visibility' command line option). ELF +defines the `default', `protected', `hidden' and `internal' +visibilities. + + The most commonly used is visibility is `hidden'. It specifies that +the symbol cannot be referenced from outside of the current shared +library. Unfortunately, this information cannot be used directly by +the link-time optimization in the compiler since the whole shared +library also might contain non-LTO objects and those are not visible to +the compiler. + + GCC solves this problem using linker plugins. A _linker plugin_ is an +interface to the linker that allows an external program to claim the +ownership of a given object file. The linker then performs the linking +procedure by querying the plugin about the symbol table of the claimed +objects and once the linking decisions are complete, the plugin is +allowed to provide the final object file before the actual linking is +made. The linker plugin obtains the symbol resolution information +which specifies which symbols provided by the claimed objects are bound +from the rest of a binary being linked. + + Currently, the linker plugin works only in combination with the Gold +linker, but a GNU ld implementation is under development. + + GCC is designed to be independent of the rest of the toolchain and +aims to support linkers without plugin support. For this reason it +does not use the linker plugin by default. Instead, the object files +are examined by `collect2' before being passed to the linker and +objects found to have LTO sections are passed to `lto1' first. This +mode does not work for library archives. The decision on what object +files from the archive are needed depends on the actual linking and +thus GCC would have to implement the linker itself. The resolution +information is missing too and thus GCC needs to make an educated guess +based on `-fwhole-program'. Without the linker plugin GCC also assumes +that symbols are declared `hidden' and not referred by non-LTO code by +default. + +24.5 Internal flags controlling `lto1' +====================================== + +The following flags are passed into `lto1' and are not meant to be used +directly from the command line. + + * -fwpa This option runs the serial part of the link-time optimizer + performing the inter-procedural propagation (WPA mode). The + compiler reads in summary information from all inputs and performs + an analysis based on summary information only. It generates + object files for subsequent runs of the link-time optimizer where + individual object files are optimized using both summary + information from the WPA mode and the actual function bodies. It + then drives the LTRANS phase. + + * -fltrans This option runs the link-time optimizer in the + local-transformation (LTRANS) mode, which reads in output from a + previous run of the LTO in WPA mode. In the LTRANS mode, LTO + optimizes an object and produces the final assembly. + + * -fltrans-output-list=FILE This option specifies a file to which + the names of LTRANS output files are written. This option is only + meaningful in conjunction with `-fwpa'. + + +File: gccint.info, Node: Funding, Next: GNU Project, Prev: LTO, Up: Top + +Funding Free Software +********************* + +If you want to have more free software a few years from now, it makes +sense for you to help encourage people to contribute funds for its +development. 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No Surrender of Others' Freedom. + + If conditions are imposed on you (whether by court order, + agreement or otherwise) that contradict the conditions of this + License, they do not excuse you from the conditions of this + License. If you cannot convey a covered work so as to satisfy + simultaneously your obligations under this License and any other + pertinent obligations, then as a consequence you may not convey it + at all. For example, if you agree to terms that obligate you to + collect a royalty for further conveying from those to whom you + convey the Program, the only way you could satisfy both those + terms and this License would be to refrain entirely from conveying + the Program. + + 13. Use with the GNU Affero General Public License. + + Notwithstanding any other provision of this License, you have + permission to link or combine any covered work with a work licensed + under version 3 of the GNU Affero General Public License into a + single combined work, and to convey the resulting work. The terms + of this License will continue to apply to the part which is the + covered work, but the special requirements of the GNU Affero + General Public License, section 13, concerning interaction through + a network will apply to the combination as such. + + 14. Revised Versions of this License. + + The Free Software Foundation may publish revised and/or new + versions of the GNU General Public License from time to time. + Such new versions will be similar in spirit to the present + version, but may differ in detail to address new problems or + concerns. + + Each version is given a distinguishing version number. If the + Program specifies that a certain numbered version of the GNU + General Public License "or any later version" applies to it, you + have the option of following the terms and conditions either of + that numbered version or of any later version published by the + Free Software Foundation. If the Program does not specify a + version number of the GNU General Public License, you may choose + any version ever published by the Free Software Foundation. + + If the Program specifies that a proxy can decide which future + versions of the GNU General Public License can be used, that + proxy's public statement of acceptance of a version permanently + authorizes you to choose that version for the Program. + + Later license versions may give you additional or different + permissions. However, no additional obligations are imposed on any + author or copyright holder as a result of your choosing to follow a + later version. + + 15. Disclaimer of Warranty. + + THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY + APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE + COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" + WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, + INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE + RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. + SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL + NECESSARY SERVICING, REPAIR OR CORRECTION. + + 16. Limitation of Liability. + + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN + WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES + AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU + FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR + CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE + THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA + BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD + PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER + PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF + THE POSSIBILITY OF SUCH DAMAGES. + + 17. Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided + above cannot be given local legal effect according to their terms, + reviewing courts shall apply local law that most closely + approximates an absolute waiver of all civil liability in + connection with the Program, unless a warranty or assumption of + liability accompanies a copy of the Program in return for a fee. + + +END OF TERMS AND CONDITIONS +=========================== + +How to Apply These Terms to Your New Programs +============================================= + +If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these +terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least the +"copyright" line and a pointer to where the full notice is found. + + ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES. + Copyright (C) YEAR NAME OF AUTHOR + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or (at + your option) any later version. + + This program is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see `http://www.gnu.org/licenses/'. + + Also add information on how to contact you by electronic and paper +mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + PROGRAM Copyright (C) YEAR NAME OF AUTHOR + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + + The hypothetical commands `show w' and `show c' should show the +appropriate parts of the General Public License. Of course, your +program's commands might be different; for a GUI interface, you would +use an "about box". + + You should also get your employer (if you work as a programmer) or +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. For more information on this, and how to apply and follow +the GNU GPL, see `http://www.gnu.org/licenses/'. + + The GNU General Public License does not permit incorporating your +program into proprietary programs. If your program is a subroutine +library, you may consider it more useful to permit linking proprietary +applications with the library. If this is what you want to do, use the +GNU Lesser General Public License instead of this License. But first, +please read `http://www.gnu.org/philosophy/why-not-lgpl.html'. + + +File: gccint.info, Node: GNU Free Documentation License, Next: Contributors, Prev: Copying, Up: Top + +GNU Free Documentation License +****************************** + + Version 1.3, 3 November 2008 + + Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. + `http://fsf.org/' + + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + 0. PREAMBLE + + The purpose of this License is to make a manual, textbook, or other + functional and useful document "free" in the sense of freedom: to + assure everyone the effective freedom to copy and redistribute it, + with or without modifying it, either commercially or + noncommercially. Secondarily, this License preserves for the + author and publisher a way to get credit for their work, while not + being considered responsible for modifications made by others. + + This License is a kind of "copyleft", which means that derivative + works of the document must themselves be free in the same sense. + It complements the GNU General Public License, which is a copyleft + license designed for free software. + + We have designed this License in order to use it for manuals for + free software, because free software needs free documentation: a + free program should come with manuals providing the same freedoms + that the software does. But this License is not limited to + software manuals; it can be used for any textual work, regardless + of subject matter or whether it is published as a printed book. + We recommend this License principally for works whose purpose is + instruction or reference. + + 1. APPLICABILITY AND DEFINITIONS + + This License applies to any manual or other work, in any medium, + that contains a notice placed by the copyright holder saying it + can be distributed under the terms of this License. Such a notice + grants a world-wide, royalty-free license, unlimited in duration, + to use that work under the conditions stated herein. The + "Document", below, refers to any such manual or work. Any member + of the public is a licensee, and is addressed as "you". 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These + Warranty Disclaimers are considered to be included by reference in + this License, but only as regards disclaiming warranties: any other + implication that these Warranty Disclaimers may have is void and + has no effect on the meaning of this License. + + 2. VERBATIM COPYING + + You may copy and distribute the Document in any medium, either + commercially or noncommercially, provided that this License, the + copyright notices, and the license notice saying this License + applies to the Document are reproduced in all copies, and that you + add no other conditions whatsoever to those of this License. You + may not use technical measures to obstruct or control the reading + or further copying of the copies you make or distribute. However, + you may accept compensation in exchange for copies. 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If you use the + latter option, you must take reasonably prudent steps, when you + begin distribution of Opaque copies in quantity, to ensure that + this Transparent copy will remain thus accessible at the stated + location until at least one year after the last time you + distribute an Opaque copy (directly or through your agents or + retailers) of that edition to the public. + + It is requested, but not required, that you contact the authors of + the Document well before redistributing any large number of + copies, to give them a chance to provide you with an updated + version of the Document. + + 4. MODIFICATIONS + + You may copy and distribute a Modified Version of the Document + under the conditions of sections 2 and 3 above, provided that you + release the Modified Version under precisely this License, with + the Modified Version filling the role of the Document, thus + licensing distribution and modification of the Modified Version to + whoever possesses a copy of it. In addition, you must do these + things in the Modified Version: + + A. Use in the Title Page (and on the covers, if any) a title + distinct from that of the Document, and from those of + previous versions (which should, if there were any, be listed + in the History section of the Document). You may use the + same title as a previous version if the original publisher of + that version gives permission. + + B. List on the Title Page, as authors, one or more persons or + entities responsible for authorship of the modifications in + the Modified Version, together with at least five of the + principal authors of the Document (all of its principal + authors, if it has fewer than five), unless they release you + from this requirement. + + C. State on the Title page the name of the publisher of the + Modified Version, as the publisher. + + D. Preserve all the copyright notices of the Document. + + E. Add an appropriate copyright notice for your modifications + adjacent to the other copyright notices. + + F. Include, immediately after the copyright notices, a license + notice giving the public permission to use the Modified + Version under the terms of this License, in the form shown in + the Addendum below. + + G. Preserve in that license notice the full lists of Invariant + Sections and required Cover Texts given in the Document's + license notice. + + H. Include an unaltered copy of this License. + + I. Preserve the section Entitled "History", Preserve its Title, + and add to it an item stating at least the title, year, new + authors, and publisher of the Modified Version as given on + the Title Page. If there is no section Entitled "History" in + the Document, create one stating the title, year, authors, + and publisher of the Document as given on its Title Page, + then add an item describing the Modified Version as stated in + the previous sentence. + + J. Preserve the network location, if any, given in the Document + for public access to a Transparent copy of the Document, and + likewise the network locations given in the Document for + previous versions it was based on. These may be placed in + the "History" section. You may omit a network location for a + work that was published at least four years before the + Document itself, or if the original publisher of the version + it refers to gives permission. + + K. For any section Entitled "Acknowledgements" or "Dedications", + Preserve the Title of the section, and preserve in the + section all the substance and tone of each of the contributor + acknowledgements and/or dedications given therein. + + L. Preserve all the Invariant Sections of the Document, + unaltered in their text and in their titles. Section numbers + or the equivalent are not considered part of the section + titles. + + M. Delete any section Entitled "Endorsements". Such a section + may not be included in the Modified Version. + + N. Do not retitle any existing section to be Entitled + "Endorsements" or to conflict in title with any Invariant + Section. + + O. Preserve any Warranty Disclaimers. + + If the Modified Version includes new front-matter sections or + appendices that qualify as Secondary Sections and contain no + material copied from the Document, you may at your option + designate some or all of these sections as invariant. To do this, + add their titles to the list of Invariant Sections in the Modified + Version's license notice. These titles must be distinct from any + other section titles. + + You may add a section Entitled "Endorsements", provided it contains + nothing but endorsements of your Modified Version by various + parties--for example, statements of peer review or that the text + has been approved by an organization as the authoritative + definition of a standard. + + You may add a passage of up to five words as a Front-Cover Text, + and a passage of up to 25 words as a Back-Cover Text, to the end + of the list of Cover Texts in the Modified Version. Only one + passage of Front-Cover Text and one of Back-Cover Text may be + added by (or through arrangements made by) any one entity. If the + Document already includes a cover text for the same cover, + previously added by you or by arrangement made by the same entity + you are acting on behalf of, you may not add another; but you may + replace the old one, on explicit permission from the previous + publisher that added the old one. + + The author(s) and publisher(s) of the Document do not by this + License give permission to use their names for publicity for or to + assert or imply endorsement of any Modified Version. + + 5. COMBINING DOCUMENTS + + You may combine the Document with other documents released under + this License, under the terms defined in section 4 above for + modified versions, provided that you include in the combination + all of the Invariant Sections of all of the original documents, + unmodified, and list them all as Invariant Sections of your + combined work in its license notice, and that you preserve all + their Warranty Disclaimers. + + The combined work need only contain one copy of this License, and + multiple identical Invariant Sections may be replaced with a single + copy. If there are multiple Invariant Sections with the same name + but different contents, make the title of each such section unique + by adding at the end of it, in parentheses, the name of the + original author or publisher of that section if known, or else a + unique number. Make the same adjustment to the section titles in + the list of Invariant Sections in the license notice of the + combined work. + + In the combination, you must combine any sections Entitled + "History" in the various original documents, forming one section + Entitled "History"; likewise combine any sections Entitled + "Acknowledgements", and any sections Entitled "Dedications". You + must delete all sections Entitled "Endorsements." + + 6. COLLECTIONS OF DOCUMENTS + + You may make a collection consisting of the Document and other + documents released under this License, and replace the individual + copies of this License in the various documents with a single copy + that is included in the collection, provided that you follow the + rules of this License for verbatim copying of each of the + documents in all other respects. + + You may extract a single document from such a collection, and + distribute it individually under this License, provided you insert + a copy of this License into the extracted document, and follow + this License in all other respects regarding verbatim copying of + that document. + + 7. AGGREGATION WITH INDEPENDENT WORKS + + A compilation of the Document or its derivatives with other + separate and independent documents or works, in or on a volume of + a storage or distribution medium, is called an "aggregate" if the + copyright resulting from the compilation is not used to limit the + legal rights of the compilation's users beyond what the individual + works permit. When the Document is included in an aggregate, this + License does not apply to the other works in the aggregate which + are not themselves derivative works of the Document. + + If the Cover Text requirement of section 3 is applicable to these + copies of the Document, then if the Document is less than one half + of the entire aggregate, the Document's Cover Texts may be placed + on covers that bracket the Document within the aggregate, or the + electronic equivalent of covers if the Document is in electronic + form. Otherwise they must appear on printed covers that bracket + the whole aggregate. + + 8. TRANSLATION + + Translation is considered a kind of modification, so you may + distribute translations of the Document under the terms of section + 4. Replacing Invariant Sections with translations requires special + permission from their copyright holders, but you may include + translations of some or all Invariant Sections in addition to the + original versions of these Invariant Sections. You may include a + translation of this License, and all the license notices in the + Document, and any Warranty Disclaimers, provided that you also + include the original English version of this License and the + original versions of those notices and disclaimers. In case of a + disagreement between the translation and the original version of + this License or a notice or disclaimer, the original version will + prevail. + + If a section in the Document is Entitled "Acknowledgements", + "Dedications", or "History", the requirement (section 4) to + Preserve its Title (section 1) will typically require changing the + actual title. + + 9. TERMINATION + + You may not copy, modify, sublicense, or distribute the Document + except as expressly provided under this License. Any attempt + otherwise to copy, modify, sublicense, or distribute it is void, + and will automatically terminate your rights under this License. + + However, if you cease all violation of this License, then your + license from a particular copyright holder is reinstated (a) + provisionally, unless and until the copyright holder explicitly + and finally terminates your license, and (b) permanently, if the + copyright holder fails to notify you of the violation by some + reasonable means prior to 60 days after the cessation. + + Moreover, your license from a particular copyright holder is + reinstated permanently if the copyright holder notifies you of the + violation by some reasonable means, this is the first time you have + received notice of violation of this License (for any work) from + that copyright holder, and you cure the violation prior to 30 days + after your receipt of the notice. + + Termination of your rights under this section does not terminate + the licenses of parties who have received copies or rights from + you under this License. If your rights have been terminated and + not permanently reinstated, receipt of a copy of some or all of + the same material does not give you any rights to use it. + + 10. FUTURE REVISIONS OF THIS LICENSE + + The Free Software Foundation may publish new, revised versions of + the GNU Free Documentation License from time to time. Such new + versions will be similar in spirit to the present version, but may + differ in detail to address new problems or concerns. See + `http://www.gnu.org/copyleft/'. + + Each version of the License is given a distinguishing version + number. If the Document specifies that a particular numbered + version of this License "or any later version" applies to it, you + have the option of following the terms and conditions either of + that specified version or of any later version that has been + published (not as a draft) by the Free Software Foundation. If + the Document does not specify a version number of this License, + you may choose any version ever published (not as a draft) by the + Free Software Foundation. If the Document specifies that a proxy + can decide which future versions of this License can be used, that + proxy's public statement of acceptance of a version permanently + authorizes you to choose that version for the Document. + + 11. RELICENSING + + "Massive Multiauthor Collaboration Site" (or "MMC Site") means any + World Wide Web server that publishes copyrightable works and also + provides prominent facilities for anybody to edit those works. A + public wiki that anybody can edit is an example of such a server. + A "Massive Multiauthor Collaboration" (or "MMC") contained in the + site means any set of copyrightable works thus published on the MMC + site. + + "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 + license published by Creative Commons Corporation, a not-for-profit + corporation with a principal place of business in San Francisco, + California, as well as future copyleft versions of that license + published by that same organization. + + "Incorporate" means to publish or republish a Document, in whole or + in part, as part of another Document. + + An MMC is "eligible for relicensing" if it is licensed under this + License, and if all works that were first published under this + License somewhere other than this MMC, and subsequently + incorporated in whole or in part into the MMC, (1) had no cover + texts or invariant sections, and (2) were thus incorporated prior + to November 1, 2008. + + The operator of an MMC Site may republish an MMC contained in the + site under CC-BY-SA on the same site at any time before August 1, + 2009, provided the MMC is eligible for relicensing. + + +ADDENDUM: How to use this License for your documents +==================================================== + +To use this License in a document you have written, include a copy of +the License in the document and put the following copyright and license +notices just after the title page: + + Copyright (C) YEAR YOUR NAME. + Permission is granted to copy, distribute and/or modify this document + under the terms of the GNU Free Documentation License, Version 1.3 + or any later version published by the Free Software Foundation; + with no Invariant Sections, no Front-Cover Texts, and no Back-Cover + Texts. A copy of the license is included in the section entitled ``GNU + Free Documentation License''. + + If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, +replace the "with...Texts." line with this: + + with the Invariant Sections being LIST THEIR TITLES, with + the Front-Cover Texts being LIST, and with the Back-Cover Texts + being LIST. + + If you have Invariant Sections without Cover Texts, or some other +combination of the three, merge those two alternatives to suit the +situation. + + If your document contains nontrivial examples of program code, we +recommend releasing these examples in parallel under your choice of +free software license, such as the GNU General Public License, to +permit their use in free software. + + +File: gccint.info, Node: Contributors, Next: Option Index, Prev: GNU Free Documentation License, Up: Top + +Contributors to GCC +******************* + +The GCC project would like to thank its many contributors. Without +them the project would not have been nearly as successful as it has +been. Any omissions in this list are accidental. Feel free to contact +<law@redhat.com> or <gerald@pfeifer.com> if you have been left out or +some of your contributions are not listed. Please keep this list in +alphabetical order. + + * Analog Devices helped implement the support for complex data types + and iterators. + + * John David Anglin for threading-related fixes and improvements to + libstdc++-v3, and the HP-UX port. + + * James van Artsdalen wrote the code that makes efficient use of the + Intel 80387 register stack. + + * Abramo and Roberto Bagnara for the SysV68 Motorola 3300 Delta + Series port. + + * Alasdair Baird for various bug fixes. + + * Giovanni Bajo for analyzing lots of complicated C++ problem + reports. + + * Peter Barada for his work to improve code generation for new + ColdFire cores. + + * Gerald Baumgartner added the signature extension to the C++ front + end. + + * Godmar Back for his Java improvements and encouragement. + + * Scott Bambrough for help porting the Java compiler. + + * Wolfgang Bangerth for processing tons of bug reports. + + * Jon Beniston for his Microsoft Windows port of Java and port to + Lattice Mico32. + + * Daniel Berlin for better DWARF2 support, faster/better + optimizations, improved alias analysis, plus migrating GCC to + Bugzilla. + + * Geoff Berry for his Java object serialization work and various + patches. + + * Uros Bizjak for the implementation of x87 math built-in functions + and for various middle end and i386 back end improvements and bug + fixes. + + * Eric Blake for helping to make GCJ and libgcj conform to the + specifications. + + * Janne Blomqvist for contributions to GNU Fortran. + + * Segher Boessenkool for various fixes. + + * Hans-J. Boehm for his garbage collector, IA-64 libffi port, and + other Java work. + + * Neil Booth for work on cpplib, lang hooks, debug hooks and other + miscellaneous clean-ups. + + * Steven Bosscher for integrating the GNU Fortran front end into GCC + and for contributing to the tree-ssa branch. + + * Eric Botcazou for fixing middle- and backend bugs left and right. + + * Per Bothner for his direction via the steering committee and + various improvements to the infrastructure for supporting new + languages. Chill front end implementation. Initial + implementations of cpplib, fix-header, config.guess, libio, and + past C++ library (libg++) maintainer. Dreaming up, designing and + implementing much of GCJ. + + * Devon Bowen helped port GCC to the Tahoe. + + * Don Bowman for mips-vxworks contributions. + + * Dave Brolley for work on cpplib and Chill. + + * Paul Brook for work on the ARM architecture and maintaining GNU + Fortran. + + * Robert Brown implemented the support for Encore 32000 systems. + + * Christian Bruel for improvements to local store elimination. + + * Herman A.J. ten Brugge for various fixes. + + * Joerg Brunsmann for Java compiler hacking and help with the GCJ + FAQ. + + * Joe Buck for his direction via the steering committee. + + * Craig Burley for leadership of the G77 Fortran effort. + + * Stephan Buys for contributing Doxygen notes for libstdc++. + + * Paolo Carlini for libstdc++ work: lots of efficiency improvements + to the C++ strings, streambufs and formatted I/O, hard detective + work on the frustrating localization issues, and keeping up with + the problem reports. + + * John Carr for his alias work, SPARC hacking, infrastructure + improvements, previous contributions to the steering committee, + loop optimizations, etc. + + * Stephane Carrez for 68HC11 and 68HC12 ports. + + * Steve Chamberlain for support for the Renesas SH and H8 processors + and the PicoJava processor, and for GCJ config fixes. + + * Glenn Chambers for help with the GCJ FAQ. + + * John-Marc Chandonia for various libgcj patches. + + * Denis Chertykov for contributing and maintaining the AVR port, the + first GCC port for an 8-bit architecture. + + * Scott Christley for his Objective-C contributions. + + * Eric Christopher for his Java porting help and clean-ups. + + * Branko Cibej for more warning contributions. + + * The GNU Classpath project for all of their merged runtime code. + + * Nick Clifton for arm, mcore, fr30, v850, m32r, rx work, `--help', + and other random hacking. + + * Michael Cook for libstdc++ cleanup patches to reduce warnings. + + * R. Kelley Cook for making GCC buildable from a read-only directory + as well as other miscellaneous build process and documentation + clean-ups. + + * Ralf Corsepius for SH testing and minor bug fixing. + + * Stan Cox for care and feeding of the x86 port and lots of behind + the scenes hacking. + + * Alex Crain provided changes for the 3b1. + + * Ian Dall for major improvements to the NS32k port. + + * Paul Dale for his work to add uClinux platform support to the m68k + backend. + + * Dario Dariol contributed the four varieties of sample programs + that print a copy of their source. + + * Russell Davidson for fstream and stringstream fixes in libstdc++. + + * Bud Davis for work on the G77 and GNU Fortran compilers. + + * Mo DeJong for GCJ and libgcj bug fixes. + + * DJ Delorie for the DJGPP port, build and libiberty maintenance, + various bug fixes, and the M32C and MeP ports. + + * Arnaud Desitter for helping to debug GNU Fortran. + + * Gabriel Dos Reis for contributions to G++, contributions and + maintenance of GCC diagnostics infrastructure, libstdc++-v3, + including `valarray<>', `complex<>', maintaining the numerics + library (including that pesky `<limits>' :-) and keeping + up-to-date anything to do with numbers. + + * Ulrich Drepper for his work on glibc, testing of GCC using glibc, + ISO C99 support, CFG dumping support, etc., plus support of the + C++ runtime libraries including for all kinds of C interface + issues, contributing and maintaining `complex<>', sanity checking + and disbursement, configuration architecture, libio maintenance, + and early math work. + + * Zdenek Dvorak for a new loop unroller and various fixes. + + * Michael Eager for his work on the Xilinx MicroBlaze port. + + * Richard Earnshaw for his ongoing work with the ARM. + + * David Edelsohn for his direction via the steering committee, + ongoing work with the RS6000/PowerPC port, help cleaning up Haifa + loop changes, doing the entire AIX port of libstdc++ with his bare + hands, and for ensuring GCC properly keeps working on AIX. + + * Kevin Ediger for the floating point formatting of num_put::do_put + in libstdc++. + + * Phil Edwards for libstdc++ work including configuration hackery, + documentation maintainer, chief breaker of the web pages, the + occasional iostream bug fix, and work on shared library symbol + versioning. + + * Paul Eggert for random hacking all over GCC. + + * Mark Elbrecht for various DJGPP improvements, and for libstdc++ + configuration support for locales and fstream-related fixes. + + * Vadim Egorov for libstdc++ fixes in strings, streambufs, and + iostreams. + + * Christian Ehrhardt for dealing with bug reports. + + * Ben Elliston for his work to move the Objective-C runtime into its + own subdirectory and for his work on autoconf. + + * Revital Eres for work on the PowerPC 750CL port. + + * Marc Espie for OpenBSD support. + + * Doug Evans for much of the global optimization framework, arc, + m32r, and SPARC work. + + * Christopher Faylor for his work on the Cygwin port and for caring + and feeding the gcc.gnu.org box and saving its users tons of spam. + + * Fred Fish for BeOS support and Ada fixes. + + * Ivan Fontes Garcia for the Portuguese translation of the GCJ FAQ. + + * Peter Gerwinski for various bug fixes and the Pascal front end. + + * Kaveh R. Ghazi for his direction via the steering committee, + amazing work to make `-W -Wall -W* -Werror' useful, and + continuously testing GCC on a plethora of platforms. Kaveh + extends his gratitude to the CAIP Center at Rutgers University for + providing him with computing resources to work on Free Software + since the late 1980s. + + * John Gilmore for a donation to the FSF earmarked improving GNU + Java. + + * Judy Goldberg for c++ contributions. + + * Torbjorn Granlund for various fixes and the c-torture testsuite, + multiply- and divide-by-constant optimization, improved long long + support, improved leaf function register allocation, and his + direction via the steering committee. + + * Anthony Green for his `-Os' contributions, the moxie port, and + Java front end work. + + * Stu Grossman for gdb hacking, allowing GCJ developers to debug + Java code. + + * Michael K. Gschwind contributed the port to the PDP-11. + + * Richard Guenther for his ongoing middle-end contributions and bug + fixes and for release management. + + * Ron Guilmette implemented the `protoize' and `unprotoize' tools, + the support for Dwarf symbolic debugging information, and much of + the support for System V Release 4. He has also worked heavily on + the Intel 386 and 860 support. + + * Mostafa Hagog for Swing Modulo Scheduling (SMS) and post reload + GCSE. + + * Bruno Haible for improvements in the runtime overhead for EH, new + warnings and assorted bug fixes. + + * Andrew Haley for his amazing Java compiler and library efforts. + + * Chris Hanson assisted in making GCC work on HP-UX for the 9000 + series 300. + + * Michael Hayes for various thankless work he's done trying to get + the c30/c40 ports functional. Lots of loop and unroll + improvements and fixes. + + * Dara Hazeghi for wading through myriads of target-specific bug + reports. + + * Kate Hedstrom for staking the G77 folks with an initial testsuite. + + * Richard Henderson for his ongoing SPARC, alpha, ia32, and ia64 + work, loop opts, and generally fixing lots of old problems we've + ignored for years, flow rewrite and lots of further stuff, + including reviewing tons of patches. + + * Aldy Hernandez for working on the PowerPC port, SIMD support, and + various fixes. + + * Nobuyuki Hikichi of Software Research Associates, Tokyo, + contributed the support for the Sony NEWS machine. + + * Kazu Hirata for caring and feeding the Renesas H8/300 port and + various fixes. + + * Katherine Holcomb for work on GNU Fortran. + + * Manfred Hollstein for his ongoing work to keep the m88k alive, lots + of testing and bug fixing, particularly of GCC configury code. + + * Steve Holmgren for MachTen patches. + + * Jan Hubicka for his x86 port improvements. + + * Falk Hueffner for working on C and optimization bug reports. + + * Bernardo Innocenti for his m68k work, including merging of + ColdFire improvements and uClinux support. + + * Christian Iseli for various bug fixes. + + * Kamil Iskra for general m68k hacking. + + * Lee Iverson for random fixes and MIPS testing. + + * Andreas Jaeger for testing and benchmarking of GCC and various bug + fixes. + + * Jakub Jelinek for his SPARC work and sibling call optimizations as + well as lots of bug fixes and test cases, and for improving the + Java build system. + + * Janis Johnson for ia64 testing and fixes, her quality improvement + sidetracks, and web page maintenance. + + * Kean Johnston for SCO OpenServer support and various fixes. + + * Tim Josling for the sample language treelang based originally on + Richard Kenner's "toy" language. + + * Nicolai Josuttis for additional libstdc++ documentation. + + * Klaus Kaempf for his ongoing work to make alpha-vms a viable + target. + + * Steven G. Kargl for work on GNU Fortran. + + * David Kashtan of SRI adapted GCC to VMS. + + * Ryszard Kabatek for many, many libstdc++ bug fixes and + optimizations of strings, especially member functions, and for + auto_ptr fixes. + + * Geoffrey Keating for his ongoing work to make the PPC work for + GNU/Linux and his automatic regression tester. + + * Brendan Kehoe for his ongoing work with G++ and for a lot of early + work in just about every part of libstdc++. + + * Oliver M. Kellogg of Deutsche Aerospace contributed the port to the + MIL-STD-1750A. + + * Richard Kenner of the New York University Ultracomputer Research + Laboratory wrote the machine descriptions for the AMD 29000, the + DEC Alpha, the IBM RT PC, and the IBM RS/6000 as well as the + support for instruction attributes. He also made changes to + better support RISC processors including changes to common + subexpression elimination, strength reduction, function calling + sequence handling, and condition code support, in addition to + generalizing the code for frame pointer elimination and delay slot + scheduling. Richard Kenner was also the head maintainer of GCC + for several years. + + * Mumit Khan for various contributions to the Cygwin and Mingw32 + ports and maintaining binary releases for Microsoft Windows hosts, + and for massive libstdc++ porting work to Cygwin/Mingw32. + + * Robin Kirkham for cpu32 support. + + * Mark Klein for PA improvements. + + * Thomas Koenig for various bug fixes. + + * Bruce Korb for the new and improved fixincludes code. + + * Benjamin Kosnik for his G++ work and for leading the libstdc++-v3 + effort. + + * Charles LaBrec contributed the support for the Integrated Solutions + 68020 system. + + * Asher Langton and Mike Kumbera for contributing Cray pointer + support to GNU Fortran, and for other GNU Fortran improvements. + + * Jeff Law for his direction via the steering committee, + coordinating the entire egcs project and GCC 2.95, rolling out + snapshots and releases, handling merges from GCC2, reviewing tons + of patches that might have fallen through the cracks else, and + random but extensive hacking. + + * Marc Lehmann for his direction via the steering committee and + helping with analysis and improvements of x86 performance. + + * Victor Leikehman for work on GNU Fortran. + + * Ted Lemon wrote parts of the RTL reader and printer. + + * Kriang Lerdsuwanakij for C++ improvements including template as + template parameter support, and many C++ fixes. + + * Warren Levy for tremendous work on libgcj (Java Runtime Library) + and random work on the Java front end. + + * Alain Lichnewsky ported GCC to the MIPS CPU. + + * Oskar Liljeblad for hacking on AWT and his many Java bug reports + and patches. + + * Robert Lipe for OpenServer support, new testsuites, testing, etc. + + * Chen Liqin for various S+core related fixes/improvement, and for + maintaining the S+core port. + + * Weiwen Liu for testing and various bug fixes. + + * Manuel Lo'pez-Iba'n~ez for improving `-Wconversion' and many other + diagnostics fixes and improvements. + + * Dave Love for his ongoing work with the Fortran front end and + runtime libraries. + + * Martin von Lo"wis for internal consistency checking infrastructure, + various C++ improvements including namespace support, and tons of + assistance with libstdc++/compiler merges. + + * H.J. Lu for his previous contributions to the steering committee, + many x86 bug reports, prototype patches, and keeping the GNU/Linux + ports working. + + * Greg McGary for random fixes and (someday) bounded pointers. + + * Andrew MacLeod for his ongoing work in building a real EH system, + various code generation improvements, work on the global + optimizer, etc. + + * Vladimir Makarov for hacking some ugly i960 problems, PowerPC + hacking improvements to compile-time performance, overall + knowledge and direction in the area of instruction scheduling, and + design and implementation of the automaton based instruction + scheduler. + + * Bob Manson for his behind the scenes work on dejagnu. + + * Philip Martin for lots of libstdc++ string and vector iterator + fixes and improvements, and string clean up and testsuites. + + * All of the Mauve project contributors, for Java test code. + + * Bryce McKinlay for numerous GCJ and libgcj fixes and improvements. + + * Adam Megacz for his work on the Microsoft Windows port of GCJ. + + * Michael Meissner for LRS framework, ia32, m32r, v850, m88k, MIPS, + powerpc, haifa, ECOFF debug support, and other assorted hacking. + + * Jason Merrill for his direction via the steering committee and + leading the G++ effort. + + * Martin Michlmayr for testing GCC on several architectures using the + entire Debian archive. + + * David Miller for his direction via the steering committee, lots of + SPARC work, improvements in jump.c and interfacing with the Linux + kernel developers. + + * Gary Miller ported GCC to Charles River Data Systems machines. + + * Alfred Minarik for libstdc++ string and ios bug fixes, and turning + the entire libstdc++ testsuite namespace-compatible. + + * Mark Mitchell for his direction via the steering committee, + mountains of C++ work, load/store hoisting out of loops, alias + analysis improvements, ISO C `restrict' support, and serving as + release manager for GCC 3.x. + + * Alan Modra for various GNU/Linux bits and testing. + + * Toon Moene for his direction via the steering committee, Fortran + maintenance, and his ongoing work to make us make Fortran run fast. + + * Jason Molenda for major help in the care and feeding of all the + services on the gcc.gnu.org (formerly egcs.cygnus.com) + machine--mail, web services, ftp services, etc etc. Doing all + this work on scrap paper and the backs of envelopes would have + been... difficult. + + * Catherine Moore for fixing various ugly problems we have sent her + way, including the haifa bug which was killing the Alpha & PowerPC + Linux kernels. + + * Mike Moreton for his various Java patches. + + * David Mosberger-Tang for various Alpha improvements, and for the + initial IA-64 port. + + * Stephen Moshier contributed the floating point emulator that + assists in cross-compilation and permits support for floating + point numbers wider than 64 bits and for ISO C99 support. + + * Bill Moyer for his behind the scenes work on various issues. + + * Philippe De Muyter for his work on the m68k port. + + * Joseph S. Myers for his work on the PDP-11 port, format checking + and ISO C99 support, and continuous emphasis on (and contributions + to) documentation. + + * Nathan Myers for his work on libstdc++-v3: architecture and + authorship through the first three snapshots, including + implementation of locale infrastructure, string, shadow C headers, + and the initial project documentation (DESIGN, CHECKLIST, and so + forth). Later, more work on MT-safe string and shadow headers. + + * Felix Natter for documentation on porting libstdc++. + + * Nathanael Nerode for cleaning up the configuration/build process. + + * NeXT, Inc. donated the front end that supports the Objective-C + language. + + * Hans-Peter Nilsson for the CRIS and MMIX ports, improvements to + the search engine setup, various documentation fixes and other + small fixes. + + * Geoff Noer for his work on getting cygwin native builds working. + + * Diego Novillo for his work on Tree SSA, OpenMP, SPEC performance + tracking web pages, GIMPLE tuples, and assorted fixes. + + * David O'Brien for the FreeBSD/alpha, FreeBSD/AMD x86-64, + FreeBSD/ARM, FreeBSD/PowerPC, and FreeBSD/SPARC64 ports and + related infrastructure improvements. + + * Alexandre Oliva for various build infrastructure improvements, + scripts and amazing testing work, including keeping libtool issues + sane and happy. + + * Stefan Olsson for work on mt_alloc. + + * Melissa O'Neill for various NeXT fixes. + + * Rainer Orth for random MIPS work, including improvements to GCC's + o32 ABI support, improvements to dejagnu's MIPS support, Java + configuration clean-ups and porting work, and maintaining the + IRIX, Solaris 2, and Tru64 UNIX ports. + + * Hartmut Penner for work on the s390 port. + + * Paul Petersen wrote the machine description for the Alliant FX/8. + + * Alexandre Petit-Bianco for implementing much of the Java compiler + and continued Java maintainership. + + * Matthias Pfaller for major improvements to the NS32k port. + + * Gerald Pfeifer for his direction via the steering committee, + pointing out lots of problems we need to solve, maintenance of the + web pages, and taking care of documentation maintenance in general. + + * Andrew Pinski for processing bug reports by the dozen. + + * Ovidiu Predescu for his work on the Objective-C front end and + runtime libraries. + + * Jerry Quinn for major performance improvements in C++ formatted + I/O. + + * Ken Raeburn for various improvements to checker, MIPS ports and + various cleanups in the compiler. + + * Rolf W. Rasmussen for hacking on AWT. + + * David Reese of Sun Microsystems contributed to the Solaris on + PowerPC port. + + * Volker Reichelt for keeping up with the problem reports. + + * Joern Rennecke for maintaining the sh port, loop, regmove & reload + hacking. + + * Loren J. Rittle for improvements to libstdc++-v3 including the + FreeBSD port, threading fixes, thread-related configury changes, + critical threading documentation, and solutions to really tricky + I/O problems, as well as keeping GCC properly working on FreeBSD + and continuous testing. + + * Craig Rodrigues for processing tons of bug reports. + + * Ola Ro"nnerup for work on mt_alloc. + + * Gavin Romig-Koch for lots of behind the scenes MIPS work. + + * David Ronis inspired and encouraged Craig to rewrite the G77 + documentation in texinfo format by contributing a first pass at a + translation of the old `g77-0.5.16/f/DOC' file. + + * Ken Rose for fixes to GCC's delay slot filling code. + + * Paul Rubin wrote most of the preprocessor. + + * Pe'tur Runo'lfsson for major performance improvements in C++ + formatted I/O and large file support in C++ filebuf. + + * Chip Salzenberg for libstdc++ patches and improvements to locales, + traits, Makefiles, libio, libtool hackery, and "long long" support. + + * Juha Sarlin for improvements to the H8 code generator. + + * Greg Satz assisted in making GCC work on HP-UX for the 9000 series + 300. + + * Roger Sayle for improvements to constant folding and GCC's RTL + optimizers as well as for fixing numerous bugs. + + * Bradley Schatz for his work on the GCJ FAQ. + + * Peter Schauer wrote the code to allow debugging to work on the + Alpha. + + * William Schelter did most of the work on the Intel 80386 support. + + * Tobias Schlu"ter for work on GNU Fortran. + + * Bernd Schmidt for various code generation improvements and major + work in the reload pass as well a serving as release manager for + GCC 2.95.3. + + * Peter Schmid for constant testing of libstdc++--especially + application testing, going above and beyond what was requested for + the release criteria--and libstdc++ header file tweaks. + + * Jason Schroeder for jcf-dump patches. + + * Andreas Schwab for his work on the m68k port. + + * Lars Segerlund for work on GNU Fortran. + + * Dodji Seketeli for numerous C++ bug fixes and debug info + improvements. + + * Joel Sherrill for his direction via the steering committee, RTEMS + contributions and RTEMS testing. + + * Nathan Sidwell for many C++ fixes/improvements. + + * Jeffrey Siegal for helping RMS with the original design of GCC, + some code which handles the parse tree and RTL data structures, + constant folding and help with the original VAX & m68k ports. + + * Kenny Simpson for prompting libstdc++ fixes due to defect reports + from the LWG (thereby keeping GCC in line with updates from the + ISO). + + * Franz Sirl for his ongoing work with making the PPC port stable + for GNU/Linux. + + * Andrey Slepuhin for assorted AIX hacking. + + * Trevor Smigiel for contributing the SPU port. + + * Christopher Smith did the port for Convex machines. + + * Danny Smith for his major efforts on the Mingw (and Cygwin) ports. + + * Randy Smith finished the Sun FPA support. + + * Scott Snyder for queue, iterator, istream, and string fixes and + libstdc++ testsuite entries. Also for providing the patch to G77 + to add rudimentary support for `INTEGER*1', `INTEGER*2', and + `LOGICAL*1'. + + * Brad Spencer for contributions to the GLIBCPP_FORCE_NEW technique. + + * Richard Stallman, for writing the original GCC and launching the + GNU project. + + * Jan Stein of the Chalmers Computer Society provided support for + Genix, as well as part of the 32000 machine description. + + * Nigel Stephens for various mips16 related fixes/improvements. + + * Jonathan Stone wrote the machine description for the Pyramid + computer. + + * Graham Stott for various infrastructure improvements. + + * John Stracke for his Java HTTP protocol fixes. + + * Mike Stump for his Elxsi port, G++ contributions over the years + and more recently his vxworks contributions + + * Jeff Sturm for Java porting help, bug fixes, and encouragement. + + * Shigeya Suzuki for this fixes for the bsdi platforms. + + * Ian Lance Taylor for the Go frontend, the initial mips16 and mips64 + support, general configury hacking, fixincludes, etc. + + * Holger Teutsch provided the support for the Clipper CPU. + + * Gary Thomas for his ongoing work to make the PPC work for + GNU/Linux. + + * Philipp Thomas for random bug fixes throughout the compiler + + * Jason Thorpe for thread support in libstdc++ on NetBSD. + + * Kresten Krab Thorup wrote the run time support for the Objective-C + language and the fantastic Java bytecode interpreter. + + * Michael Tiemann for random bug fixes, the first instruction + scheduler, initial C++ support, function integration, NS32k, SPARC + and M88k machine description work, delay slot scheduling. + + * Andreas Tobler for his work porting libgcj to Darwin. + + * Teemu Torma for thread safe exception handling support. + + * Leonard Tower wrote parts of the parser, RTL generator, and RTL + definitions, and of the VAX machine description. + + * Daniel Towner and Hariharan Sandanagobalane contributed and + maintain the picoChip port. + + * Tom Tromey for internationalization support and for his many Java + contributions and libgcj maintainership. + + * Lassi Tuura for improvements to config.guess to determine HP + processor types. + + * Petter Urkedal for libstdc++ CXXFLAGS, math, and algorithms fixes. + + * Andy Vaught for the design and initial implementation of the GNU + Fortran front end. + + * Brent Verner for work with the libstdc++ cshadow files and their + associated configure steps. + + * Todd Vierling for contributions for NetBSD ports. + + * Jonathan Wakely for contributing libstdc++ Doxygen notes and XHTML + guidance. + + * Dean Wakerley for converting the install documentation from HTML + to texinfo in time for GCC 3.0. + + * Krister Walfridsson for random bug fixes. + + * Feng Wang for contributions to GNU Fortran. + + * Stephen M. Webb for time and effort on making libstdc++ shadow + files work with the tricky Solaris 8+ headers, and for pushing the + build-time header tree. + + * John Wehle for various improvements for the x86 code generator, + related infrastructure improvements to help x86 code generation, + value range propagation and other work, WE32k port. + + * Ulrich Weigand for work on the s390 port. + + * Zack Weinberg for major work on cpplib and various other bug fixes. + + * Matt Welsh for help with Linux Threads support in GCJ. + + * Urban Widmark for help fixing java.io. + + * Mark Wielaard for new Java library code and his work integrating + with Classpath. + + * Dale Wiles helped port GCC to the Tahoe. + + * Bob Wilson from Tensilica, Inc. for the Xtensa port. + + * Jim Wilson for his direction via the steering committee, tackling + hard problems in various places that nobody else wanted to work + on, strength reduction and other loop optimizations. + + * Paul Woegerer and Tal Agmon for the CRX port. + + * Carlo Wood for various fixes. + + * Tom Wood for work on the m88k port. + + * Canqun Yang for work on GNU Fortran. + + * Masanobu Yuhara of Fujitsu Laboratories implemented the machine + description for the Tron architecture (specifically, the Gmicro). + + * Kevin Zachmann helped port GCC to the Tahoe. + + * Ayal Zaks for Swing Modulo Scheduling (SMS). + + * Xiaoqiang Zhang for work on GNU Fortran. + + * Gilles Zunino for help porting Java to Irix. + + + The following people are recognized for their contributions to GNAT, +the Ada front end of GCC: + * Bernard Banner + + * Romain Berrendonner + + * Geert Bosch + + * Emmanuel Briot + + * Joel Brobecker + + * Ben Brosgol + + * Vincent Celier + + * Arnaud Charlet + + * Chien Chieng + + * Cyrille Comar + + * Cyrille Crozes + + * Robert Dewar + + * Gary Dismukes + + * Robert Duff + + * Ed Falis + + * Ramon Fernandez + + * Sam Figueroa + + * Vasiliy Fofanov + + * Michael Friess + + * Franco Gasperoni + + * Ted Giering + + * Matthew Gingell + + * Laurent Guerby + + * Jerome Guitton + + * Olivier Hainque + + * Jerome Hugues + + * Hristian Kirtchev + + * Jerome Lambourg + + * Bruno Leclerc + + * Albert Lee + + * Sean McNeil + + * Javier Miranda + + * Laurent Nana + + * Pascal Obry + + * Dong-Ik Oh + + * Laurent Pautet + + * Brett Porter + + * Thomas Quinot + + * Nicolas Roche + + * Pat Rogers + + * Jose Ruiz + + * Douglas Rupp + + * Sergey Rybin + + * Gail Schenker + + * Ed Schonberg + + * Nicolas Setton + + * Samuel Tardieu + + + The following people are recognized for their contributions of new +features, bug reports, testing and integration of classpath/libgcj for +GCC version 4.1: + * Lillian Angel for `JTree' implementation and lots Free Swing + additions and bug fixes. + + * Wolfgang Baer for `GapContent' bug fixes. + + * Anthony Balkissoon for `JList', Free Swing 1.5 updates and mouse + event fixes, lots of Free Swing work including `JTable' editing. + + * Stuart Ballard for RMI constant fixes. + + * Goffredo Baroncelli for `HTTPURLConnection' fixes. + + * Gary Benson for `MessageFormat' fixes. + + * Daniel Bonniot for `Serialization' fixes. + + * Chris Burdess for lots of gnu.xml and http protocol fixes, `StAX' + and `DOM xml:id' support. + + * Ka-Hing Cheung for `TreePath' and `TreeSelection' fixes. + + * Archie Cobbs for build fixes, VM interface updates, + `URLClassLoader' updates. + + * Kelley Cook for build fixes. + + * Martin Cordova for Suggestions for better `SocketTimeoutException'. + + * David Daney for `BitSet' bug fixes, `HttpURLConnection' rewrite + and improvements. + + * Thomas Fitzsimmons for lots of upgrades to the gtk+ AWT and Cairo + 2D support. Lots of imageio framework additions, lots of AWT and + Free Swing bug fixes. + + * Jeroen Frijters for `ClassLoader' and nio cleanups, serialization + fixes, better `Proxy' support, bug fixes and IKVM integration. + + * Santiago Gala for `AccessControlContext' fixes. + + * Nicolas Geoffray for `VMClassLoader' and `AccessController' + improvements. + + * David Gilbert for `basic' and `metal' icon and plaf support and + lots of documenting, Lots of Free Swing and metal theme additions. + `MetalIconFactory' implementation. + + * Anthony Green for `MIDI' framework, `ALSA' and `DSSI' providers. + + * Andrew Haley for `Serialization' and `URLClassLoader' fixes, gcj + build speedups. + + * Kim Ho for `JFileChooser' implementation. + + * Andrew John Hughes for `Locale' and net fixes, URI RFC2986 + updates, `Serialization' fixes, `Properties' XML support and + generic branch work, VMIntegration guide update. + + * Bastiaan Huisman for `TimeZone' bug fixing. + + * Andreas Jaeger for mprec updates. + + * Paul Jenner for better `-Werror' support. + + * Ito Kazumitsu for `NetworkInterface' implementation and updates. + + * Roman Kennke for `BoxLayout', `GrayFilter' and `SplitPane', plus + bug fixes all over. Lots of Free Swing work including styled text. + + * Simon Kitching for `String' cleanups and optimization suggestions. + + * Michael Koch for configuration fixes, `Locale' updates, bug and + build fixes. + + * Guilhem Lavaux for configuration, thread and channel fixes and + Kaffe integration. JCL native `Pointer' updates. Logger bug fixes. + + * David Lichteblau for JCL support library global/local reference + cleanups. + + * Aaron Luchko for JDWP updates and documentation fixes. + + * Ziga Mahkovec for `Graphics2D' upgraded to Cairo 0.5 and new regex + features. + + * Sven de Marothy for BMP imageio support, CSS and `TextLayout' + fixes. `GtkImage' rewrite, 2D, awt, free swing and date/time fixes + and implementing the Qt4 peers. + + * Casey Marshall for crypto algorithm fixes, `FileChannel' lock, + `SystemLogger' and `FileHandler' rotate implementations, NIO + `FileChannel.map' support, security and policy updates. + + * Bryce McKinlay for RMI work. + + * Audrius Meskauskas for lots of Free Corba, RMI and HTML work plus + testing and documenting. + + * Kalle Olavi Niemitalo for build fixes. + + * Rainer Orth for build fixes. + + * Andrew Overholt for `File' locking fixes. + + * Ingo Proetel for `Image', `Logger' and `URLClassLoader' updates. + + * Olga Rodimina for `MenuSelectionManager' implementation. + + * Jan Roehrich for `BasicTreeUI' and `JTree' fixes. + + * Julian Scheid for documentation updates and gjdoc support. + + * Christian Schlichtherle for zip fixes and cleanups. + + * Robert Schuster for documentation updates and beans fixes, + `TreeNode' enumerations and `ActionCommand' and various fixes, XML + and URL, AWT and Free Swing bug fixes. + + * Keith Seitz for lots of JDWP work. + + * Christian Thalinger for 64-bit cleanups, Configuration and VM + interface fixes and `CACAO' integration, `fdlibm' updates. + + * Gael Thomas for `VMClassLoader' boot packages support suggestions. + + * Andreas Tobler for Darwin and Solaris testing and fixing, `Qt4' + support for Darwin/OS X, `Graphics2D' support, `gtk+' updates. + + * Dalibor Topic for better `DEBUG' support, build cleanups and Kaffe + integration. `Qt4' build infrastructure, `SHA1PRNG' and + `GdkPixbugDecoder' updates. + + * Tom Tromey for Eclipse integration, generics work, lots of bug + fixes and gcj integration including coordinating The Big Merge. + + * Mark Wielaard for bug fixes, packaging and release management, + `Clipboard' implementation, system call interrupts and network + timeouts and `GdkPixpufDecoder' fixes. + + + In addition to the above, all of which also contributed time and +energy in testing GCC, we would like to thank the following for their +contributions to testing: + + * Michael Abd-El-Malek + + * Thomas Arend + + * Bonzo Armstrong + + * Steven Ashe + + * Chris Baldwin + + * David Billinghurst + + * Jim Blandy + + * Stephane Bortzmeyer + + * Horst von Brand + + * Frank Braun + + * Rodney Brown + + * Sidney Cadot + + * Bradford Castalia + + * Robert Clark + + * Jonathan Corbet + + * Ralph Doncaster + + * Richard Emberson + + * Levente Farkas + + * Graham Fawcett + + * Mark Fernyhough + + * Robert A. French + + * Jo"rgen Freyh + + * Mark K. Gardner + + * Charles-Antoine Gauthier + + * Yung Shing Gene + + * David Gilbert + + * Simon Gornall + + * Fred Gray + + * John Griffin + + * Patrik Hagglund + + * Phil Hargett + + * Amancio Hasty + + * Takafumi Hayashi + + * Bryan W. Headley + + * Kevin B. Hendricks + + * Joep Jansen + + * Christian Joensson + + * Michel Kern + + * David Kidd + + * Tobias Kuipers + + * Anand Krishnaswamy + + * A. O. V. Le Blanc + + * llewelly + + * Damon Love + + * Brad Lucier + + * Matthias Klose + + * Martin Knoblauch + + * Rick Lutowski + + * Jesse Macnish + + * Stefan Morrell + + * Anon A. Mous + + * Matthias Mueller + + * Pekka Nikander + + * Rick Niles + + * Jon Olson + + * Magnus Persson + + * Chris Pollard + + * Richard Polton + + * Derk Reefman + + * David Rees + + * Paul Reilly + + * Tom Reilly + + * Torsten Rueger + + * Danny Sadinoff + + * Marc Schifer + + * Erik Schnetter + + * Wayne K. Schroll + + * David Schuler + + * Vin Shelton + + * Tim Souder + + * Adam Sulmicki + + * Bill Thorson + + * George Talbot + + * Pedro A. M. Vazquez + + * Gregory Warnes + + * Ian Watson + + * David E. Young + + * And many others + + And finally we'd like to thank everyone who uses the compiler, provides +feedback and generally reminds us why we're doing this work in the first +place. + + +File: gccint.info, Node: Option Index, Next: Concept Index, Prev: Contributors, Up: Top + +Option Index +************ + +GCC's command line options are indexed here without any initial `-' or +`--'. Where an option has both positive and negative forms (such as +`-fOPTION' and `-fno-OPTION'), relevant entries in the manual are +indexed under the most appropriate form; it may sometimes be useful to +look up both forms. + + +* Menu: + +* fltrans: LTO. (line 499) +* fltrans-output-list: LTO. (line 504) +* fwpa: LTO. (line 490) +* msoft-float: Soft float library routines. + (line 6) + + +File: gccint.info, Node: Concept Index, Prev: Option Index, Up: Top + +Concept Index +************* + + +* Menu: + +* ! in constraint: Multi-Alternative. (line 47) +* # in constraint: Modifiers. (line 67) +* # in template: Output Template. (line 66) +* #pragma: Misc. (line 381) +* % in constraint: Modifiers. (line 45) +* % in GTY option: GTY Options. (line 18) +* % in template: Output Template. (line 6) +* & in constraint: Modifiers. (line 25) +* (nil): RTL Objects. (line 73) +* * in constraint: Modifiers. (line 72) +* * in template: Output Statement. (line 29) +* + in constraint: Modifiers. (line 12) +* -fsection-anchors <1>: Anchored Addresses. (line 6) +* -fsection-anchors: Special Accessors. (line 110) +* /c in RTL dump: Flags. (line 239) +* /f in RTL dump: Flags. (line 247) +* /i in RTL dump: Flags. (line 299) +* /j in RTL dump: Flags. (line 314) +* /s in RTL dump: Flags. (line 263) +* /u in RTL dump: Flags. (line 324) +* /v in RTL dump: Flags. (line 356) +* 0 in constraint: Simple Constraints. (line 130) +* < in constraint: Simple Constraints. (line 48) +* = in constraint: Modifiers. (line 8) +* > in constraint: Simple Constraints. (line 61) +* ? in constraint: Multi-Alternative. (line 41) +* \: Output Template. (line 46) +* __absvdi2: Integer library routines. + (line 107) +* __absvsi2: Integer library routines. + (line 106) +* __addda3: Fixed-point fractional library routines. + (line 45) +* __adddf3: Soft float library routines. + (line 23) +* __adddq3: Fixed-point fractional library routines. + (line 33) +* __addha3: Fixed-point fractional library routines. + (line 43) +* __addhq3: Fixed-point fractional library routines. + (line 30) +* __addqq3: Fixed-point fractional library routines. + (line 29) +* __addsa3: Fixed-point fractional library routines. + (line 44) +* __addsf3: Soft float library routines. + (line 22) +* __addsq3: Fixed-point fractional library routines. + (line 31) +* __addta3: Fixed-point fractional library routines. + (line 47) +* __addtf3: Soft float library routines. + (line 25) +* __adduda3: Fixed-point fractional library routines. + (line 53) +* __addudq3: Fixed-point fractional library routines. + (line 41) +* __adduha3: Fixed-point fractional library routines. + (line 49) +* __adduhq3: Fixed-point fractional library routines. + (line 37) +* __adduqq3: Fixed-point fractional library routines. + (line 35) +* __addusa3: Fixed-point fractional library routines. + (line 51) +* __addusq3: Fixed-point fractional library routines. + (line 39) +* __adduta3: Fixed-point fractional library routines. + (line 55) +* __addvdi3: Integer library routines. + (line 111) +* __addvsi3: Integer library routines. + (line 110) +* __addxf3: Soft float library routines. + (line 27) +* __ashlda3: Fixed-point fractional library routines. + (line 351) +* __ashldi3: Integer library routines. + (line 14) +* __ashldq3: Fixed-point fractional library routines. + (line 340) +* __ashlha3: Fixed-point fractional library routines. + (line 349) +* __ashlhq3: Fixed-point fractional library routines. + (line 337) +* __ashlqq3: Fixed-point fractional library routines. + (line 336) +* __ashlsa3: Fixed-point fractional library routines. + (line 350) +* __ashlsi3: Integer library routines. + (line 13) +* __ashlsq3: Fixed-point fractional library routines. + (line 338) +* __ashlta3: Fixed-point fractional library routines. + (line 353) +* __ashlti3: Integer library routines. + (line 15) +* __ashluda3: Fixed-point fractional library routines. + (line 359) +* __ashludq3: Fixed-point fractional library routines. + (line 348) +* __ashluha3: Fixed-point fractional library routines. + (line 355) +* __ashluhq3: Fixed-point fractional library routines. + (line 344) +* __ashluqq3: Fixed-point fractional library routines. + (line 342) +* __ashlusa3: Fixed-point fractional library routines. + (line 357) +* __ashlusq3: Fixed-point fractional library routines. + (line 346) +* __ashluta3: Fixed-point fractional library routines. + (line 361) +* __ashrda3: Fixed-point fractional library routines. + (line 371) +* __ashrdi3: Integer library routines. + (line 19) +* __ashrdq3: Fixed-point fractional library routines. + (line 368) +* __ashrha3: Fixed-point fractional library routines. + (line 369) +* __ashrhq3: Fixed-point fractional library routines. + (line 365) +* __ashrqq3: Fixed-point fractional library routines. + (line 364) +* __ashrsa3: Fixed-point fractional library routines. + (line 370) +* __ashrsi3: Integer library routines. + (line 18) +* __ashrsq3: Fixed-point fractional library routines. + (line 366) +* __ashrta3: Fixed-point fractional library routines. + (line 373) +* __ashrti3: Integer library routines. + (line 20) +* __bid_adddd3: Decimal float library routines. + (line 25) +* __bid_addsd3: Decimal float library routines. + (line 21) +* __bid_addtd3: Decimal float library routines. + (line 29) +* __bid_divdd3: Decimal float library routines. + (line 68) +* __bid_divsd3: Decimal float library routines. + (line 64) +* __bid_divtd3: Decimal float library routines. + (line 72) +* __bid_eqdd2: Decimal float library routines. + (line 259) +* __bid_eqsd2: Decimal float library routines. + (line 257) +* __bid_eqtd2: Decimal float library routines. + (line 261) +* __bid_extendddtd2: Decimal float library routines. + (line 92) +* __bid_extendddtf: Decimal float library routines. + (line 140) +* __bid_extendddxf: Decimal float library routines. + (line 134) +* __bid_extenddfdd: Decimal float library routines. + (line 147) +* __bid_extenddftd: Decimal float library routines. + (line 107) +* __bid_extendsddd2: Decimal float library routines. + (line 88) +* __bid_extendsddf: Decimal float library routines. + (line 128) +* __bid_extendsdtd2: Decimal float library routines. + (line 90) +* __bid_extendsdtf: Decimal float library routines. + (line 138) +* __bid_extendsdxf: Decimal float library routines. + (line 132) +* __bid_extendsfdd: Decimal float library routines. + (line 103) +* __bid_extendsfsd: Decimal float library routines. + (line 145) +* __bid_extendsftd: Decimal float library routines. + (line 105) +* __bid_extendtftd: Decimal float library routines. + (line 149) +* __bid_extendxftd: Decimal float library routines. + (line 109) +* __bid_fixdddi: Decimal float library routines. + (line 170) +* __bid_fixddsi: Decimal float library routines. + (line 162) +* __bid_fixsddi: Decimal float library routines. + (line 168) +* __bid_fixsdsi: Decimal float library routines. + (line 160) +* __bid_fixtddi: Decimal float library routines. + (line 172) +* __bid_fixtdsi: Decimal float library routines. + (line 164) +* __bid_fixunsdddi: Decimal float library routines. + (line 187) +* __bid_fixunsddsi: Decimal float library routines. + (line 178) +* __bid_fixunssddi: Decimal float library routines. + (line 185) +* __bid_fixunssdsi: Decimal float library routines. + (line 176) +* __bid_fixunstddi: Decimal float library routines. + (line 189) +* __bid_fixunstdsi: Decimal float library routines. + (line 180) +* __bid_floatdidd: Decimal float library routines. + (line 205) +* __bid_floatdisd: Decimal float library routines. + (line 203) +* __bid_floatditd: Decimal float library routines. + (line 207) +* __bid_floatsidd: Decimal float library routines. + (line 196) +* __bid_floatsisd: Decimal float library routines. + (line 194) +* __bid_floatsitd: Decimal float library routines. + (line 198) +* __bid_floatunsdidd: Decimal float library routines. + (line 223) +* __bid_floatunsdisd: Decimal float library routines. + (line 221) +* __bid_floatunsditd: Decimal float library routines. + (line 225) +* __bid_floatunssidd: Decimal float library routines. + (line 214) +* __bid_floatunssisd: Decimal float library routines. + (line 212) +* __bid_floatunssitd: Decimal float library routines. + (line 216) +* __bid_gedd2: Decimal float library routines. + (line 277) +* __bid_gesd2: Decimal float library routines. + (line 275) +* __bid_getd2: Decimal float library routines. + (line 279) +* __bid_gtdd2: Decimal float library routines. + (line 304) +* __bid_gtsd2: Decimal float library routines. + (line 302) +* __bid_gttd2: Decimal float library routines. + (line 306) +* __bid_ledd2: Decimal float library routines. + (line 295) +* __bid_lesd2: Decimal float library routines. + (line 293) +* __bid_letd2: Decimal float library routines. + (line 297) +* __bid_ltdd2: Decimal float library routines. + (line 286) +* __bid_ltsd2: Decimal float library routines. + (line 284) +* __bid_lttd2: Decimal float library routines. + (line 288) +* __bid_muldd3: Decimal float library routines. + (line 54) +* __bid_mulsd3: Decimal float library routines. + (line 50) +* __bid_multd3: Decimal float library routines. + (line 58) +* __bid_nedd2: Decimal float library routines. + (line 268) +* __bid_negdd2: Decimal float library routines. + (line 78) +* __bid_negsd2: Decimal float library routines. + (line 76) +* __bid_negtd2: Decimal float library routines. + (line 80) +* __bid_nesd2: Decimal float library routines. + (line 266) +* __bid_netd2: Decimal float library routines. + (line 270) +* __bid_subdd3: Decimal float library routines. + (line 39) +* __bid_subsd3: Decimal float library routines. + (line 35) +* __bid_subtd3: Decimal float library routines. + (line 43) +* __bid_truncdddf: Decimal float library routines. + (line 153) +* __bid_truncddsd2: Decimal float library routines. + (line 94) +* __bid_truncddsf: Decimal float library routines. + (line 124) +* __bid_truncdfsd: Decimal float library routines. + (line 111) +* __bid_truncsdsf: Decimal float library routines. + (line 151) +* __bid_trunctddd2: Decimal float library routines. + (line 98) +* __bid_trunctddf: Decimal float library routines. + (line 130) +* __bid_trunctdsd2: Decimal float library routines. + (line 96) +* __bid_trunctdsf: Decimal float library routines. + (line 126) +* __bid_trunctdtf: Decimal float library routines. + (line 155) +* __bid_trunctdxf: Decimal float library routines. + (line 136) +* __bid_trunctfdd: Decimal float library routines. + (line 119) +* __bid_trunctfsd: Decimal float library routines. + (line 115) +* __bid_truncxfdd: Decimal float library routines. + (line 117) +* __bid_truncxfsd: Decimal float library routines. + (line 113) +* __bid_unorddd2: Decimal float library routines. + (line 235) +* __bid_unordsd2: Decimal float library routines. + (line 233) +* __bid_unordtd2: Decimal float library routines. + (line 237) +* __bswapdi2: Integer library routines. + (line 162) +* __bswapsi2: Integer library routines. + (line 161) +* __builtin_classify_type: Varargs. (line 51) +* __builtin_next_arg: Varargs. (line 42) +* __builtin_saveregs: Varargs. (line 24) +* __clear_cache: Miscellaneous routines. + (line 10) +* __clzdi2: Integer library routines. + (line 131) +* __clzsi2: Integer library routines. + (line 130) +* __clzti2: Integer library routines. + (line 132) +* __cmpda2: Fixed-point fractional library routines. + (line 451) +* __cmpdf2: Soft float library routines. + (line 164) +* __cmpdi2: Integer library routines. + (line 87) +* __cmpdq2: Fixed-point fractional library routines. + (line 441) +* __cmpha2: Fixed-point fractional library routines. + (line 449) +* __cmphq2: Fixed-point fractional library routines. + (line 438) +* __cmpqq2: Fixed-point fractional library routines. + (line 437) +* __cmpsa2: Fixed-point fractional library routines. + (line 450) +* __cmpsf2: Soft float library routines. + (line 163) +* __cmpsq2: Fixed-point fractional library routines. + (line 439) +* __cmpta2: Fixed-point fractional library routines. + (line 453) +* __cmptf2: Soft float library routines. + (line 165) +* __cmpti2: Integer library routines. + (line 88) +* __cmpuda2: Fixed-point fractional library routines. + (line 458) +* __cmpudq2: Fixed-point fractional library routines. + (line 448) +* __cmpuha2: Fixed-point fractional library routines. + (line 455) +* __cmpuhq2: Fixed-point fractional library routines. + (line 444) +* __cmpuqq2: Fixed-point fractional library routines. + (line 443) +* __cmpusa2: Fixed-point fractional library routines. + (line 456) +* __cmpusq2: Fixed-point fractional library routines. + (line 446) +* __cmputa2: Fixed-point fractional library routines. + (line 460) +* __CTOR_LIST__: Initialization. (line 25) +* __ctzdi2: Integer library routines. + (line 138) +* __ctzsi2: Integer library routines. + (line 137) +* __ctzti2: Integer library routines. + (line 139) +* __divda3: Fixed-point fractional library routines. + (line 227) +* __divdc3: Soft float library routines. + (line 252) +* __divdf3: Soft float library routines. + (line 48) +* __divdi3: Integer library routines. + (line 25) +* __divdq3: Fixed-point fractional library routines. + (line 223) +* __divha3: Fixed-point fractional library routines. + (line 225) +* __divhq3: Fixed-point fractional library routines. + (line 220) +* __divqq3: Fixed-point fractional library routines. + (line 219) +* __divsa3: Fixed-point fractional library routines. + (line 226) +* __divsc3: Soft float library routines. + (line 250) +* __divsf3: Soft float library routines. + (line 47) +* __divsi3: Integer library routines. + (line 24) +* __divsq3: Fixed-point fractional library routines. + (line 221) +* __divta3: Fixed-point fractional library routines. + (line 229) +* __divtc3: Soft float library routines. + (line 254) +* __divtf3: Soft float library routines. + (line 50) +* __divti3: Integer library routines. + (line 26) +* __divxc3: Soft float library routines. + (line 256) +* __divxf3: Soft float library routines. + (line 52) +* __dpd_adddd3: Decimal float library routines. + (line 23) +* __dpd_addsd3: Decimal float library routines. + (line 19) +* __dpd_addtd3: Decimal float library routines. + (line 27) +* __dpd_divdd3: Decimal float library routines. + (line 66) +* __dpd_divsd3: Decimal float library routines. + (line 62) +* __dpd_divtd3: Decimal float library routines. + (line 70) +* __dpd_eqdd2: Decimal float library routines. + (line 258) +* __dpd_eqsd2: Decimal float library routines. + (line 256) +* __dpd_eqtd2: Decimal float library routines. + (line 260) +* __dpd_extendddtd2: Decimal float library routines. + (line 91) +* __dpd_extendddtf: Decimal float library routines. + (line 139) +* __dpd_extendddxf: Decimal float library routines. + (line 133) +* __dpd_extenddfdd: Decimal float library routines. + (line 146) +* __dpd_extenddftd: Decimal float library routines. + (line 106) +* __dpd_extendsddd2: Decimal float library routines. + (line 87) +* __dpd_extendsddf: Decimal float library routines. + (line 127) +* __dpd_extendsdtd2: Decimal float library routines. + (line 89) +* __dpd_extendsdtf: Decimal float library routines. + (line 137) +* __dpd_extendsdxf: Decimal float library routines. + (line 131) +* __dpd_extendsfdd: Decimal float library routines. + (line 102) +* __dpd_extendsfsd: Decimal float library routines. + (line 144) +* __dpd_extendsftd: Decimal float library routines. + (line 104) +* __dpd_extendtftd: Decimal float library routines. + (line 148) +* __dpd_extendxftd: Decimal float library routines. + (line 108) +* __dpd_fixdddi: Decimal float library routines. + (line 169) +* __dpd_fixddsi: Decimal float library routines. + (line 161) +* __dpd_fixsddi: Decimal float library routines. + (line 167) +* __dpd_fixsdsi: Decimal float library routines. + (line 159) +* __dpd_fixtddi: Decimal float library routines. + (line 171) +* __dpd_fixtdsi: Decimal float library routines. + (line 163) +* __dpd_fixunsdddi: Decimal float library routines. + (line 186) +* __dpd_fixunsddsi: Decimal float library routines. + (line 177) +* __dpd_fixunssddi: Decimal float library routines. + (line 184) +* __dpd_fixunssdsi: Decimal float library routines. + (line 175) +* __dpd_fixunstddi: Decimal float library routines. + (line 188) +* __dpd_fixunstdsi: Decimal float library routines. + (line 179) +* __dpd_floatdidd: Decimal float library routines. + (line 204) +* __dpd_floatdisd: Decimal float library routines. + (line 202) +* __dpd_floatditd: Decimal float library routines. + (line 206) +* __dpd_floatsidd: Decimal float library routines. + (line 195) +* __dpd_floatsisd: Decimal float library routines. + (line 193) +* __dpd_floatsitd: Decimal float library routines. + (line 197) +* __dpd_floatunsdidd: Decimal float library routines. + (line 222) +* __dpd_floatunsdisd: Decimal float library routines. + (line 220) +* __dpd_floatunsditd: Decimal float library routines. + (line 224) +* __dpd_floatunssidd: Decimal float library routines. + (line 213) +* __dpd_floatunssisd: Decimal float library routines. + (line 211) +* __dpd_floatunssitd: Decimal float library routines. + (line 215) +* __dpd_gedd2: Decimal float library routines. + (line 276) +* __dpd_gesd2: Decimal float library routines. + (line 274) +* __dpd_getd2: Decimal float library routines. + (line 278) +* __dpd_gtdd2: Decimal float library routines. + (line 303) +* __dpd_gtsd2: Decimal float library routines. + (line 301) +* __dpd_gttd2: Decimal float library routines. + (line 305) +* __dpd_ledd2: Decimal float library routines. + (line 294) +* __dpd_lesd2: Decimal float library routines. + (line 292) +* __dpd_letd2: Decimal float library routines. + (line 296) +* __dpd_ltdd2: Decimal float library routines. + (line 285) +* __dpd_ltsd2: Decimal float library routines. + (line 283) +* __dpd_lttd2: Decimal float library routines. + (line 287) +* __dpd_muldd3: Decimal float library routines. + (line 52) +* __dpd_mulsd3: Decimal float library routines. + (line 48) +* __dpd_multd3: Decimal float library routines. + (line 56) +* __dpd_nedd2: Decimal float library routines. + (line 267) +* __dpd_negdd2: Decimal float library routines. + (line 77) +* __dpd_negsd2: Decimal float library routines. + (line 75) +* __dpd_negtd2: Decimal float library routines. + (line 79) +* __dpd_nesd2: Decimal float library routines. + (line 265) +* __dpd_netd2: Decimal float library routines. + (line 269) +* __dpd_subdd3: Decimal float library routines. + (line 37) +* __dpd_subsd3: Decimal float library routines. + (line 33) +* __dpd_subtd3: Decimal float library routines. + (line 41) +* __dpd_truncdddf: Decimal float library routines. + (line 152) +* __dpd_truncddsd2: Decimal float library routines. + (line 93) +* __dpd_truncddsf: Decimal float library routines. + (line 123) +* __dpd_truncdfsd: Decimal float library routines. + (line 110) +* __dpd_truncsdsf: Decimal float library routines. + (line 150) +* __dpd_trunctddd2: Decimal float library routines. + (line 97) +* __dpd_trunctddf: Decimal float library routines. + (line 129) +* __dpd_trunctdsd2: Decimal float library routines. + (line 95) +* __dpd_trunctdsf: Decimal float library routines. + (line 125) +* __dpd_trunctdtf: Decimal float library routines. + (line 154) +* __dpd_trunctdxf: Decimal float library routines. + (line 135) +* __dpd_trunctfdd: Decimal float library routines. + (line 118) +* __dpd_trunctfsd: Decimal float library routines. + (line 114) +* __dpd_truncxfdd: Decimal float library routines. + (line 116) +* __dpd_truncxfsd: Decimal float library routines. + (line 112) +* __dpd_unorddd2: Decimal float library routines. + (line 234) +* __dpd_unordsd2: Decimal float library routines. + (line 232) +* __dpd_unordtd2: Decimal float library routines. + (line 236) +* __DTOR_LIST__: Initialization. (line 25) +* __eqdf2: Soft float library routines. + (line 194) +* __eqsf2: Soft float library routines. + (line 193) +* __eqtf2: Soft float library routines. + (line 195) +* __extenddftf2: Soft float library routines. + (line 68) +* __extenddfxf2: Soft float library routines. + (line 69) +* __extendsfdf2: Soft float library routines. + (line 65) +* __extendsftf2: Soft float library routines. + (line 66) +* __extendsfxf2: Soft float library routines. + (line 67) +* __ffsdi2: Integer library routines. + (line 144) +* __ffsti2: Integer library routines. + (line 145) +* __fixdfdi: Soft float library routines. + (line 88) +* __fixdfsi: Soft float library routines. + (line 81) +* __fixdfti: Soft float library routines. + (line 94) +* __fixsfdi: Soft float library routines. + (line 87) +* __fixsfsi: Soft float library routines. + (line 80) +* __fixsfti: Soft float library routines. + (line 93) +* __fixtfdi: Soft float library routines. + (line 89) +* __fixtfsi: Soft float library routines. + (line 82) +* __fixtfti: Soft float library routines. + (line 95) +* __fixunsdfdi: Soft float library routines. + (line 108) +* __fixunsdfsi: Soft float library routines. + (line 101) +* __fixunsdfti: Soft float library routines. + (line 115) +* __fixunssfdi: Soft float library routines. + (line 107) +* __fixunssfsi: Soft float library routines. + (line 100) +* __fixunssfti: Soft float library routines. + (line 114) +* __fixunstfdi: Soft float library routines. + (line 109) +* __fixunstfsi: Soft float library routines. + (line 102) +* __fixunstfti: Soft float library routines. + (line 116) +* __fixunsxfdi: Soft float library routines. + (line 110) +* __fixunsxfsi: Soft float library routines. + (line 103) +* __fixunsxfti: Soft float library routines. + (line 117) +* __fixxfdi: Soft float library routines. + (line 90) +* __fixxfsi: Soft float library routines. + (line 83) +* __fixxfti: Soft float library routines. + (line 96) +* __floatdidf: Soft float library routines. + (line 128) +* __floatdisf: Soft float library routines. + (line 127) +* __floatditf: Soft float library routines. + (line 129) +* __floatdixf: Soft float library routines. + (line 130) +* __floatsidf: Soft float library routines. + (line 122) +* __floatsisf: Soft float library routines. + (line 121) +* __floatsitf: Soft float library routines. + (line 123) +* __floatsixf: Soft float library routines. + (line 124) +* __floattidf: Soft float library routines. + (line 134) +* __floattisf: Soft float library routines. + (line 133) +* __floattitf: Soft float library routines. + (line 135) +* __floattixf: Soft float library routines. + (line 136) +* __floatundidf: Soft float library routines. + (line 146) +* __floatundisf: Soft float library routines. + (line 145) +* __floatunditf: Soft float library routines. + (line 147) +* __floatundixf: Soft float library routines. + (line 148) +* __floatunsidf: Soft float library routines. + (line 140) +* __floatunsisf: Soft float library routines. + (line 139) +* __floatunsitf: Soft float library routines. + (line 141) +* __floatunsixf: Soft float library routines. + (line 142) +* __floatuntidf: Soft float library routines. + (line 152) +* __floatuntisf: Soft float library routines. + (line 151) +* __floatuntitf: Soft float library routines. + (line 153) +* __floatuntixf: Soft float library routines. + (line 154) +* __fractdadf: Fixed-point fractional library routines. + (line 636) +* __fractdadi: Fixed-point fractional library routines. + (line 633) +* __fractdadq: Fixed-point fractional library routines. + (line 616) +* __fractdaha2: Fixed-point fractional library routines. + (line 617) +* __fractdahi: Fixed-point fractional library routines. + (line 631) +* __fractdahq: Fixed-point fractional library routines. + (line 614) +* __fractdaqi: Fixed-point fractional library routines. + (line 630) +* __fractdaqq: Fixed-point fractional library routines. + (line 613) +* __fractdasa2: Fixed-point fractional library routines. + (line 618) +* __fractdasf: Fixed-point fractional library routines. + (line 635) +* __fractdasi: Fixed-point fractional library routines. + (line 632) +* __fractdasq: Fixed-point fractional library routines. + (line 615) +* __fractdata2: Fixed-point fractional library routines. + (line 619) +* __fractdati: Fixed-point fractional library routines. + (line 634) +* __fractdauda: Fixed-point fractional library routines. + (line 627) +* __fractdaudq: Fixed-point fractional library routines. + (line 624) +* __fractdauha: Fixed-point fractional library routines. + (line 625) +* __fractdauhq: Fixed-point fractional library routines. + (line 621) +* __fractdauqq: Fixed-point fractional library routines. + (line 620) +* __fractdausa: Fixed-point fractional library routines. + (line 626) +* __fractdausq: Fixed-point fractional library routines. + (line 622) +* __fractdauta: Fixed-point fractional library routines. + (line 629) +* __fractdfda: Fixed-point fractional library routines. + (line 1025) +* __fractdfdq: Fixed-point fractional library routines. + (line 1022) +* __fractdfha: Fixed-point fractional library routines. + (line 1023) +* __fractdfhq: Fixed-point fractional library routines. + (line 1020) +* __fractdfqq: Fixed-point fractional library routines. + (line 1019) +* __fractdfsa: Fixed-point fractional library routines. + (line 1024) +* __fractdfsq: Fixed-point fractional library routines. + (line 1021) +* __fractdfta: Fixed-point fractional library routines. + (line 1026) +* __fractdfuda: Fixed-point fractional library routines. + (line 1033) +* __fractdfudq: Fixed-point fractional library routines. + (line 1030) +* __fractdfuha: Fixed-point fractional library routines. + (line 1031) +* __fractdfuhq: Fixed-point fractional library routines. + (line 1028) +* __fractdfuqq: Fixed-point fractional library routines. + (line 1027) +* __fractdfusa: Fixed-point fractional library routines. + (line 1032) +* __fractdfusq: Fixed-point fractional library routines. + (line 1029) +* __fractdfuta: Fixed-point fractional library routines. + (line 1034) +* __fractdida: Fixed-point fractional library routines. + (line 975) +* __fractdidq: Fixed-point fractional library routines. + (line 972) +* __fractdiha: Fixed-point fractional library routines. + (line 973) +* __fractdihq: Fixed-point fractional library routines. + (line 970) +* __fractdiqq: Fixed-point fractional library routines. + (line 969) +* __fractdisa: Fixed-point fractional library routines. + (line 974) +* __fractdisq: Fixed-point fractional library routines. + (line 971) +* __fractdita: Fixed-point fractional library routines. + (line 976) +* __fractdiuda: Fixed-point fractional library routines. + (line 983) +* __fractdiudq: Fixed-point fractional library routines. + (line 980) +* __fractdiuha: Fixed-point fractional library routines. + (line 981) +* __fractdiuhq: Fixed-point fractional library routines. + (line 978) +* __fractdiuqq: Fixed-point fractional library routines. + (line 977) +* __fractdiusa: Fixed-point fractional library routines. + (line 982) +* __fractdiusq: Fixed-point fractional library routines. + (line 979) +* __fractdiuta: Fixed-point fractional library routines. + (line 984) +* __fractdqda: Fixed-point fractional library routines. + (line 544) +* __fractdqdf: Fixed-point fractional library routines. + (line 566) +* __fractdqdi: Fixed-point fractional library routines. + (line 563) +* __fractdqha: Fixed-point fractional library routines. + (line 542) +* __fractdqhi: Fixed-point fractional library routines. + (line 561) +* __fractdqhq2: Fixed-point fractional library routines. + (line 540) +* __fractdqqi: Fixed-point fractional library routines. + (line 560) +* __fractdqqq2: Fixed-point fractional library routines. + (line 539) +* __fractdqsa: Fixed-point fractional library routines. + (line 543) +* __fractdqsf: Fixed-point fractional library routines. + (line 565) +* __fractdqsi: Fixed-point fractional library routines. + (line 562) +* __fractdqsq2: Fixed-point fractional library routines. + (line 541) +* __fractdqta: Fixed-point fractional library routines. + (line 545) +* __fractdqti: Fixed-point fractional library routines. + (line 564) +* __fractdquda: Fixed-point fractional library routines. + (line 557) +* __fractdqudq: Fixed-point fractional library routines. + (line 552) +* __fractdquha: Fixed-point fractional library routines. + (line 554) +* __fractdquhq: Fixed-point fractional library routines. + (line 548) +* __fractdquqq: Fixed-point fractional library routines. + (line 547) +* __fractdqusa: Fixed-point fractional library routines. + (line 555) +* __fractdqusq: Fixed-point fractional library routines. + (line 550) +* __fractdquta: Fixed-point fractional library routines. + (line 559) +* __fracthada2: Fixed-point fractional library routines. + (line 572) +* __fracthadf: Fixed-point fractional library routines. + (line 590) +* __fracthadi: Fixed-point fractional library routines. + (line 587) +* __fracthadq: Fixed-point fractional library routines. + (line 570) +* __fracthahi: Fixed-point fractional library routines. + (line 585) +* __fracthahq: Fixed-point fractional library routines. + (line 568) +* __fracthaqi: Fixed-point fractional library routines. + (line 584) +* __fracthaqq: Fixed-point fractional library routines. + (line 567) +* __fracthasa2: Fixed-point fractional library routines. + (line 571) +* __fracthasf: Fixed-point fractional library routines. + (line 589) +* __fracthasi: Fixed-point fractional library routines. + (line 586) +* __fracthasq: Fixed-point fractional library routines. + (line 569) +* __fracthata2: Fixed-point fractional library routines. + (line 573) +* __fracthati: Fixed-point fractional library routines. + (line 588) +* __fracthauda: Fixed-point fractional library routines. + (line 581) +* __fracthaudq: Fixed-point fractional library routines. + (line 578) +* __fracthauha: Fixed-point fractional library routines. + (line 579) +* __fracthauhq: Fixed-point fractional library routines. + (line 575) +* __fracthauqq: Fixed-point fractional library routines. + (line 574) +* __fracthausa: Fixed-point fractional library routines. + (line 580) +* __fracthausq: Fixed-point fractional library routines. + (line 576) +* __fracthauta: Fixed-point fractional library routines. + (line 583) +* __fracthida: Fixed-point fractional library routines. + (line 943) +* __fracthidq: Fixed-point fractional library routines. + (line 940) +* __fracthiha: Fixed-point fractional library routines. + (line 941) +* __fracthihq: Fixed-point fractional library routines. + (line 938) +* __fracthiqq: Fixed-point fractional library routines. + (line 937) +* __fracthisa: Fixed-point fractional library routines. + (line 942) +* __fracthisq: Fixed-point fractional library routines. + (line 939) +* __fracthita: Fixed-point fractional library routines. + (line 944) +* __fracthiuda: Fixed-point fractional library routines. + (line 951) +* __fracthiudq: Fixed-point fractional library routines. + (line 948) +* __fracthiuha: Fixed-point fractional library routines. + (line 949) +* __fracthiuhq: Fixed-point fractional library routines. + (line 946) +* __fracthiuqq: Fixed-point fractional library routines. + (line 945) +* __fracthiusa: Fixed-point fractional library routines. + (line 950) +* __fracthiusq: Fixed-point fractional library routines. + (line 947) +* __fracthiuta: Fixed-point fractional library routines. + (line 952) +* __fracthqda: Fixed-point fractional library routines. + (line 498) +* __fracthqdf: Fixed-point fractional library routines. + (line 514) +* __fracthqdi: Fixed-point fractional library routines. + (line 511) +* __fracthqdq2: Fixed-point fractional library routines. + (line 495) +* __fracthqha: Fixed-point fractional library routines. + (line 496) +* __fracthqhi: Fixed-point fractional library routines. + (line 509) +* __fracthqqi: Fixed-point fractional library routines. + (line 508) +* __fracthqqq2: Fixed-point fractional library routines. + (line 493) +* __fracthqsa: Fixed-point fractional library routines. + (line 497) +* __fracthqsf: Fixed-point fractional library routines. + (line 513) +* __fracthqsi: Fixed-point fractional library routines. + (line 510) +* __fracthqsq2: Fixed-point fractional library routines. + (line 494) +* __fracthqta: Fixed-point fractional library routines. + (line 499) +* __fracthqti: Fixed-point fractional library routines. + (line 512) +* __fracthquda: Fixed-point fractional library routines. + (line 506) +* __fracthqudq: Fixed-point fractional library routines. + (line 503) +* __fracthquha: Fixed-point fractional library routines. + (line 504) +* __fracthquhq: Fixed-point fractional library routines. + (line 501) +* __fracthquqq: Fixed-point fractional library routines. + (line 500) +* __fracthqusa: Fixed-point fractional library routines. + (line 505) +* __fracthqusq: Fixed-point fractional library routines. + (line 502) +* __fracthquta: Fixed-point fractional library routines. + (line 507) +* __fractqida: Fixed-point fractional library routines. + (line 925) +* __fractqidq: Fixed-point fractional library routines. + (line 922) +* __fractqiha: Fixed-point fractional library routines. + (line 923) +* __fractqihq: Fixed-point fractional library routines. + (line 920) +* __fractqiqq: Fixed-point fractional library routines. + (line 919) +* __fractqisa: Fixed-point fractional library routines. + (line 924) +* __fractqisq: Fixed-point fractional library routines. + (line 921) +* __fractqita: Fixed-point fractional library routines. + (line 926) +* __fractqiuda: Fixed-point fractional library routines. + (line 934) +* __fractqiudq: Fixed-point fractional library routines. + (line 931) +* __fractqiuha: Fixed-point fractional library routines. + (line 932) +* __fractqiuhq: Fixed-point fractional library routines. + (line 928) +* __fractqiuqq: Fixed-point fractional library routines. + (line 927) +* __fractqiusa: Fixed-point fractional library routines. + (line 933) +* __fractqiusq: Fixed-point fractional library routines. + (line 929) +* __fractqiuta: Fixed-point fractional library routines. + (line 936) +* __fractqqda: Fixed-point fractional library routines. + (line 474) +* __fractqqdf: Fixed-point fractional library routines. + (line 492) +* __fractqqdi: Fixed-point fractional library routines. + (line 489) +* __fractqqdq2: Fixed-point fractional library routines. + (line 471) +* __fractqqha: Fixed-point fractional library routines. + (line 472) +* __fractqqhi: Fixed-point fractional library routines. + (line 487) +* __fractqqhq2: Fixed-point fractional library routines. + (line 469) +* __fractqqqi: Fixed-point fractional library routines. + (line 486) +* __fractqqsa: Fixed-point fractional library routines. + (line 473) +* __fractqqsf: Fixed-point fractional library routines. + (line 491) +* __fractqqsi: Fixed-point fractional library routines. + (line 488) +* __fractqqsq2: Fixed-point fractional library routines. + (line 470) +* __fractqqta: Fixed-point fractional library routines. + (line 475) +* __fractqqti: Fixed-point fractional library routines. + (line 490) +* __fractqquda: Fixed-point fractional library routines. + (line 483) +* __fractqqudq: Fixed-point fractional library routines. + (line 480) +* __fractqquha: Fixed-point fractional library routines. + (line 481) +* __fractqquhq: Fixed-point fractional library routines. + (line 477) +* __fractqquqq: Fixed-point fractional library routines. + (line 476) +* __fractqqusa: Fixed-point fractional library routines. + (line 482) +* __fractqqusq: Fixed-point fractional library routines. + (line 478) +* __fractqquta: Fixed-point fractional library routines. + (line 485) +* __fractsada2: Fixed-point fractional library routines. + (line 596) +* __fractsadf: Fixed-point fractional library routines. + (line 612) +* __fractsadi: Fixed-point fractional library routines. + (line 609) +* __fractsadq: Fixed-point fractional library routines. + (line 594) +* __fractsaha2: Fixed-point fractional library routines. + (line 595) +* __fractsahi: Fixed-point fractional library routines. + (line 607) +* __fractsahq: Fixed-point fractional library routines. + (line 592) +* __fractsaqi: Fixed-point fractional library routines. + (line 606) +* __fractsaqq: Fixed-point fractional library routines. + (line 591) +* __fractsasf: Fixed-point fractional library routines. + (line 611) +* __fractsasi: Fixed-point fractional library routines. + (line 608) +* __fractsasq: Fixed-point fractional library routines. + (line 593) +* __fractsata2: Fixed-point fractional library routines. + (line 597) +* __fractsati: Fixed-point fractional library routines. + (line 610) +* __fractsauda: Fixed-point fractional library routines. + (line 604) +* __fractsaudq: Fixed-point fractional library routines. + (line 601) +* __fractsauha: Fixed-point fractional library routines. + (line 602) +* __fractsauhq: Fixed-point fractional library routines. + (line 599) +* __fractsauqq: Fixed-point fractional library routines. + (line 598) +* __fractsausa: Fixed-point fractional library routines. + (line 603) +* __fractsausq: Fixed-point fractional library routines. + (line 600) +* __fractsauta: Fixed-point fractional library routines. + (line 605) +* __fractsfda: Fixed-point fractional library routines. + (line 1009) +* __fractsfdq: Fixed-point fractional library routines. + (line 1006) +* __fractsfha: Fixed-point fractional library routines. + (line 1007) +* __fractsfhq: Fixed-point fractional library routines. + (line 1004) +* __fractsfqq: Fixed-point fractional library routines. + (line 1003) +* __fractsfsa: Fixed-point fractional library routines. + (line 1008) +* __fractsfsq: Fixed-point fractional library routines. + (line 1005) +* __fractsfta: Fixed-point fractional library routines. + (line 1010) +* __fractsfuda: Fixed-point fractional library routines. + (line 1017) +* __fractsfudq: Fixed-point fractional library routines. + (line 1014) +* __fractsfuha: Fixed-point fractional library routines. + (line 1015) +* __fractsfuhq: Fixed-point fractional library routines. + (line 1012) +* __fractsfuqq: Fixed-point fractional library routines. + (line 1011) +* __fractsfusa: Fixed-point fractional library routines. + (line 1016) +* __fractsfusq: Fixed-point fractional library routines. + (line 1013) +* __fractsfuta: Fixed-point fractional library routines. + (line 1018) +* __fractsida: Fixed-point fractional library routines. + (line 959) +* __fractsidq: Fixed-point fractional library routines. + (line 956) +* __fractsiha: Fixed-point fractional library routines. + (line 957) +* __fractsihq: Fixed-point fractional library routines. + (line 954) +* __fractsiqq: Fixed-point fractional library routines. + (line 953) +* __fractsisa: Fixed-point fractional library routines. + (line 958) +* __fractsisq: Fixed-point fractional library routines. + (line 955) +* __fractsita: Fixed-point fractional library routines. + (line 960) +* __fractsiuda: Fixed-point fractional library routines. + (line 967) +* __fractsiudq: Fixed-point fractional library routines. + (line 964) +* __fractsiuha: Fixed-point fractional library routines. + (line 965) +* __fractsiuhq: Fixed-point fractional library routines. + (line 962) +* __fractsiuqq: Fixed-point fractional library routines. + (line 961) +* __fractsiusa: Fixed-point fractional library routines. + (line 966) +* __fractsiusq: Fixed-point fractional library routines. + (line 963) +* __fractsiuta: Fixed-point fractional library routines. + (line 968) +* __fractsqda: Fixed-point fractional library routines. + (line 520) +* __fractsqdf: Fixed-point fractional library routines. + (line 538) +* __fractsqdi: Fixed-point fractional library routines. + (line 535) +* __fractsqdq2: Fixed-point fractional library routines. + (line 517) +* __fractsqha: Fixed-point fractional library routines. + (line 518) +* __fractsqhi: Fixed-point fractional library routines. + (line 533) +* __fractsqhq2: Fixed-point fractional library routines. + (line 516) +* __fractsqqi: Fixed-point fractional library routines. + (line 532) +* __fractsqqq2: Fixed-point fractional library routines. + (line 515) +* __fractsqsa: Fixed-point fractional library routines. + (line 519) +* __fractsqsf: Fixed-point fractional library routines. + (line 537) +* __fractsqsi: Fixed-point fractional library routines. + (line 534) +* __fractsqta: Fixed-point fractional library routines. + (line 521) +* __fractsqti: Fixed-point fractional library routines. + (line 536) +* __fractsquda: Fixed-point fractional library routines. + (line 529) +* __fractsqudq: Fixed-point fractional library routines. + (line 526) +* __fractsquha: Fixed-point fractional library routines. + (line 527) +* __fractsquhq: Fixed-point fractional library routines. + (line 523) +* __fractsquqq: Fixed-point fractional library routines. + (line 522) +* __fractsqusa: Fixed-point fractional library routines. + (line 528) +* __fractsqusq: Fixed-point fractional library routines. + (line 524) +* __fractsquta: Fixed-point fractional library routines. + (line 531) +* __fracttada2: Fixed-point fractional library routines. + (line 643) +* __fracttadf: Fixed-point fractional library routines. + (line 664) +* __fracttadi: Fixed-point fractional library routines. + (line 661) +* __fracttadq: Fixed-point fractional library routines. + (line 640) +* __fracttaha2: Fixed-point fractional library routines. + (line 641) +* __fracttahi: Fixed-point fractional library routines. + (line 659) +* __fracttahq: Fixed-point fractional library routines. + (line 638) +* __fracttaqi: Fixed-point fractional library routines. + (line 658) +* __fracttaqq: Fixed-point fractional library routines. + (line 637) +* __fracttasa2: Fixed-point fractional library routines. + (line 642) +* __fracttasf: Fixed-point fractional library routines. + (line 663) +* __fracttasi: Fixed-point fractional library routines. + (line 660) +* __fracttasq: Fixed-point fractional library routines. + (line 639) +* __fracttati: Fixed-point fractional library routines. + (line 662) +* __fracttauda: Fixed-point fractional library routines. + (line 655) +* __fracttaudq: Fixed-point fractional library routines. + (line 650) +* __fracttauha: Fixed-point fractional library routines. + (line 652) +* __fracttauhq: Fixed-point fractional library routines. + (line 646) +* __fracttauqq: Fixed-point fractional library routines. + (line 645) +* __fracttausa: Fixed-point fractional library routines. + (line 653) +* __fracttausq: Fixed-point fractional library routines. + (line 648) +* __fracttauta: Fixed-point fractional library routines. + (line 657) +* __fracttida: Fixed-point fractional library routines. + (line 991) +* __fracttidq: Fixed-point fractional library routines. + (line 988) +* __fracttiha: Fixed-point fractional library routines. + (line 989) +* __fracttihq: Fixed-point fractional library routines. + (line 986) +* __fracttiqq: Fixed-point fractional library routines. + (line 985) +* __fracttisa: Fixed-point fractional library routines. + (line 990) +* __fracttisq: Fixed-point fractional library routines. + (line 987) +* __fracttita: Fixed-point fractional library routines. + (line 992) +* __fracttiuda: Fixed-point fractional library routines. + (line 1000) +* __fracttiudq: Fixed-point fractional library routines. + (line 997) +* __fracttiuha: Fixed-point fractional library routines. + (line 998) +* __fracttiuhq: Fixed-point fractional library routines. + (line 994) +* __fracttiuqq: Fixed-point fractional library routines. + (line 993) +* __fracttiusa: Fixed-point fractional library routines. + (line 999) +* __fracttiusq: Fixed-point fractional library routines. + (line 995) +* __fracttiuta: Fixed-point fractional library routines. + (line 1002) +* __fractudada: Fixed-point fractional library routines. + (line 858) +* __fractudadf: Fixed-point fractional library routines. + (line 881) +* __fractudadi: Fixed-point fractional library routines. + (line 878) +* __fractudadq: Fixed-point fractional library routines. + (line 855) +* __fractudaha: Fixed-point fractional library routines. + (line 856) +* __fractudahi: Fixed-point fractional library routines. + (line 876) +* __fractudahq: Fixed-point fractional library routines. + (line 852) +* __fractudaqi: Fixed-point fractional library routines. + (line 875) +* __fractudaqq: Fixed-point fractional library routines. + (line 851) +* __fractudasa: Fixed-point fractional library routines. + (line 857) +* __fractudasf: Fixed-point fractional library routines. + (line 880) +* __fractudasi: Fixed-point fractional library routines. + (line 877) +* __fractudasq: Fixed-point fractional library routines. + (line 853) +* __fractudata: Fixed-point fractional library routines. + (line 860) +* __fractudati: Fixed-point fractional library routines. + (line 879) +* __fractudaudq: Fixed-point fractional library routines. + (line 868) +* __fractudauha2: Fixed-point fractional library routines. + (line 870) +* __fractudauhq: Fixed-point fractional library routines. + (line 864) +* __fractudauqq: Fixed-point fractional library routines. + (line 862) +* __fractudausa2: Fixed-point fractional library routines. + (line 872) +* __fractudausq: Fixed-point fractional library routines. + (line 866) +* __fractudauta2: Fixed-point fractional library routines. + (line 874) +* __fractudqda: Fixed-point fractional library routines. + (line 766) +* __fractudqdf: Fixed-point fractional library routines. + (line 791) +* __fractudqdi: Fixed-point fractional library routines. + (line 787) +* __fractudqdq: Fixed-point fractional library routines. + (line 761) +* __fractudqha: Fixed-point fractional library routines. + (line 763) +* __fractudqhi: Fixed-point fractional library routines. + (line 785) +* __fractudqhq: Fixed-point fractional library routines. + (line 757) +* __fractudqqi: Fixed-point fractional library routines. + (line 784) +* __fractudqqq: Fixed-point fractional library routines. + (line 756) +* __fractudqsa: Fixed-point fractional library routines. + (line 764) +* __fractudqsf: Fixed-point fractional library routines. + (line 790) +* __fractudqsi: Fixed-point fractional library routines. + (line 786) +* __fractudqsq: Fixed-point fractional library routines. + (line 759) +* __fractudqta: Fixed-point fractional library routines. + (line 768) +* __fractudqti: Fixed-point fractional library routines. + (line 789) +* __fractudquda: Fixed-point fractional library routines. + (line 780) +* __fractudquha: Fixed-point fractional library routines. + (line 776) +* __fractudquhq2: Fixed-point fractional library routines. + (line 772) +* __fractudquqq2: Fixed-point fractional library routines. + (line 770) +* __fractudqusa: Fixed-point fractional library routines. + (line 778) +* __fractudqusq2: Fixed-point fractional library routines. + (line 774) +* __fractudquta: Fixed-point fractional library routines. + (line 782) +* __fractuhada: Fixed-point fractional library routines. + (line 799) +* __fractuhadf: Fixed-point fractional library routines. + (line 822) +* __fractuhadi: Fixed-point fractional library routines. + (line 819) +* __fractuhadq: Fixed-point fractional library routines. + (line 796) +* __fractuhaha: Fixed-point fractional library routines. + (line 797) +* __fractuhahi: Fixed-point fractional library routines. + (line 817) +* __fractuhahq: Fixed-point fractional library routines. + (line 793) +* __fractuhaqi: Fixed-point fractional library routines. + (line 816) +* __fractuhaqq: Fixed-point fractional library routines. + (line 792) +* __fractuhasa: Fixed-point fractional library routines. + (line 798) +* __fractuhasf: Fixed-point fractional library routines. + (line 821) +* __fractuhasi: Fixed-point fractional library routines. + (line 818) +* __fractuhasq: Fixed-point fractional library routines. + (line 794) +* __fractuhata: Fixed-point fractional library routines. + (line 801) +* __fractuhati: Fixed-point fractional library routines. + (line 820) +* __fractuhauda2: Fixed-point fractional library routines. + (line 813) +* __fractuhaudq: Fixed-point fractional library routines. + (line 809) +* __fractuhauhq: Fixed-point fractional library routines. + (line 805) +* __fractuhauqq: Fixed-point fractional library routines. + (line 803) +* __fractuhausa2: Fixed-point fractional library routines. + (line 811) +* __fractuhausq: Fixed-point fractional library routines. + (line 807) +* __fractuhauta2: Fixed-point fractional library routines. + (line 815) +* __fractuhqda: Fixed-point fractional library routines. + (line 702) +* __fractuhqdf: Fixed-point fractional library routines. + (line 723) +* __fractuhqdi: Fixed-point fractional library routines. + (line 720) +* __fractuhqdq: Fixed-point fractional library routines. + (line 699) +* __fractuhqha: Fixed-point fractional library routines. + (line 700) +* __fractuhqhi: Fixed-point fractional library routines. + (line 718) +* __fractuhqhq: Fixed-point fractional library routines. + (line 697) +* __fractuhqqi: Fixed-point fractional library routines. + (line 717) +* __fractuhqqq: Fixed-point fractional library routines. + (line 696) +* __fractuhqsa: Fixed-point fractional library routines. + (line 701) +* __fractuhqsf: Fixed-point fractional library routines. + (line 722) +* __fractuhqsi: Fixed-point fractional library routines. + (line 719) +* __fractuhqsq: Fixed-point fractional library routines. + (line 698) +* __fractuhqta: Fixed-point fractional library routines. + (line 703) +* __fractuhqti: Fixed-point fractional library routines. + (line 721) +* __fractuhquda: Fixed-point fractional library routines. + (line 714) +* __fractuhqudq2: Fixed-point fractional library routines. + (line 709) +* __fractuhquha: Fixed-point fractional library routines. + (line 711) +* __fractuhquqq2: Fixed-point fractional library routines. + (line 705) +* __fractuhqusa: Fixed-point fractional library routines. + (line 712) +* __fractuhqusq2: Fixed-point fractional library routines. + (line 707) +* __fractuhquta: Fixed-point fractional library routines. + (line 716) +* __fractunsdadi: Fixed-point fractional library routines. + (line 1555) +* __fractunsdahi: Fixed-point fractional library routines. + (line 1553) +* __fractunsdaqi: Fixed-point fractional library routines. + (line 1552) +* __fractunsdasi: Fixed-point fractional library routines. + (line 1554) +* __fractunsdati: Fixed-point fractional library routines. + (line 1556) +* __fractunsdida: Fixed-point fractional library routines. + (line 1707) +* __fractunsdidq: Fixed-point fractional library routines. + (line 1704) +* __fractunsdiha: Fixed-point fractional library routines. + (line 1705) +* __fractunsdihq: Fixed-point fractional library routines. + (line 1702) +* __fractunsdiqq: Fixed-point fractional library routines. + (line 1701) +* __fractunsdisa: Fixed-point fractional library routines. + (line 1706) +* __fractunsdisq: Fixed-point fractional library routines. + (line 1703) +* __fractunsdita: Fixed-point fractional library routines. + (line 1708) +* __fractunsdiuda: Fixed-point fractional library routines. + (line 1720) +* __fractunsdiudq: Fixed-point fractional library routines. + (line 1715) +* __fractunsdiuha: Fixed-point fractional library routines. + (line 1717) +* __fractunsdiuhq: Fixed-point fractional library routines. + (line 1711) +* __fractunsdiuqq: Fixed-point fractional library routines. + (line 1710) +* __fractunsdiusa: Fixed-point fractional library routines. + (line 1718) +* __fractunsdiusq: Fixed-point fractional library routines. + (line 1713) +* __fractunsdiuta: Fixed-point fractional library routines. + (line 1722) +* __fractunsdqdi: Fixed-point fractional library routines. + (line 1539) +* __fractunsdqhi: Fixed-point fractional library routines. + (line 1537) +* __fractunsdqqi: Fixed-point fractional library routines. + (line 1536) +* __fractunsdqsi: Fixed-point fractional library routines. + (line 1538) +* __fractunsdqti: Fixed-point fractional library routines. + (line 1541) +* __fractunshadi: Fixed-point fractional library routines. + (line 1545) +* __fractunshahi: Fixed-point fractional library routines. + (line 1543) +* __fractunshaqi: Fixed-point fractional library routines. + (line 1542) +* __fractunshasi: Fixed-point fractional library routines. + (line 1544) +* __fractunshati: Fixed-point fractional library routines. + (line 1546) +* __fractunshida: Fixed-point fractional library routines. + (line 1663) +* __fractunshidq: Fixed-point fractional library routines. + (line 1660) +* __fractunshiha: Fixed-point fractional library routines. + (line 1661) +* __fractunshihq: Fixed-point fractional library routines. + (line 1658) +* __fractunshiqq: Fixed-point fractional library routines. + (line 1657) +* __fractunshisa: Fixed-point fractional library routines. + (line 1662) +* __fractunshisq: Fixed-point fractional library routines. + (line 1659) +* __fractunshita: Fixed-point fractional library routines. + (line 1664) +* __fractunshiuda: Fixed-point fractional library routines. + (line 1676) +* __fractunshiudq: Fixed-point fractional library routines. + (line 1671) +* __fractunshiuha: Fixed-point fractional library routines. + (line 1673) +* __fractunshiuhq: Fixed-point fractional library routines. + (line 1667) +* __fractunshiuqq: Fixed-point fractional library routines. + (line 1666) +* __fractunshiusa: Fixed-point fractional library routines. + (line 1674) +* __fractunshiusq: Fixed-point fractional library routines. + (line 1669) +* __fractunshiuta: Fixed-point fractional library routines. + (line 1678) +* __fractunshqdi: Fixed-point fractional library routines. + (line 1529) +* __fractunshqhi: Fixed-point fractional library routines. + (line 1527) +* __fractunshqqi: Fixed-point fractional library routines. + (line 1526) +* __fractunshqsi: Fixed-point fractional library routines. + (line 1528) +* __fractunshqti: Fixed-point fractional library routines. + (line 1530) +* __fractunsqida: Fixed-point fractional library routines. + (line 1641) +* __fractunsqidq: Fixed-point fractional library routines. + (line 1638) +* __fractunsqiha: Fixed-point fractional library routines. + (line 1639) +* __fractunsqihq: Fixed-point fractional library routines. + (line 1636) +* __fractunsqiqq: Fixed-point fractional library routines. + (line 1635) +* __fractunsqisa: Fixed-point fractional library routines. + (line 1640) +* __fractunsqisq: Fixed-point fractional library routines. + (line 1637) +* __fractunsqita: Fixed-point fractional library routines. + (line 1642) +* __fractunsqiuda: Fixed-point fractional library routines. + (line 1654) +* __fractunsqiudq: Fixed-point fractional library routines. + (line 1649) +* __fractunsqiuha: Fixed-point fractional library routines. + (line 1651) +* __fractunsqiuhq: Fixed-point fractional library routines. + (line 1645) +* __fractunsqiuqq: Fixed-point fractional library routines. + (line 1644) +* __fractunsqiusa: Fixed-point fractional library routines. + (line 1652) +* __fractunsqiusq: Fixed-point fractional library routines. + (line 1647) +* __fractunsqiuta: Fixed-point fractional library routines. + (line 1656) +* __fractunsqqdi: Fixed-point fractional library routines. + (line 1524) +* __fractunsqqhi: Fixed-point fractional library routines. + (line 1522) +* __fractunsqqqi: Fixed-point fractional library routines. + (line 1521) +* __fractunsqqsi: Fixed-point fractional library routines. + (line 1523) +* __fractunsqqti: Fixed-point fractional library routines. + (line 1525) +* __fractunssadi: Fixed-point fractional library routines. + (line 1550) +* __fractunssahi: Fixed-point fractional library routines. + (line 1548) +* __fractunssaqi: Fixed-point fractional library routines. + (line 1547) +* __fractunssasi: Fixed-point fractional library routines. + (line 1549) +* __fractunssati: Fixed-point fractional library routines. + (line 1551) +* __fractunssida: Fixed-point fractional library routines. + (line 1685) +* __fractunssidq: Fixed-point fractional library routines. + (line 1682) +* __fractunssiha: Fixed-point fractional library routines. + (line 1683) +* __fractunssihq: Fixed-point fractional library routines. + (line 1680) +* __fractunssiqq: Fixed-point fractional library routines. + (line 1679) +* __fractunssisa: Fixed-point fractional library routines. + (line 1684) +* __fractunssisq: Fixed-point fractional library routines. + (line 1681) +* __fractunssita: Fixed-point fractional library routines. + (line 1686) +* __fractunssiuda: Fixed-point fractional library routines. + (line 1698) +* __fractunssiudq: Fixed-point fractional library routines. + (line 1693) +* __fractunssiuha: Fixed-point fractional library routines. + (line 1695) +* __fractunssiuhq: Fixed-point fractional library routines. + (line 1689) +* __fractunssiuqq: Fixed-point fractional library routines. + (line 1688) +* __fractunssiusa: Fixed-point fractional library routines. + (line 1696) +* __fractunssiusq: Fixed-point fractional library routines. + (line 1691) +* __fractunssiuta: Fixed-point fractional library routines. + (line 1700) +* __fractunssqdi: Fixed-point fractional library routines. + (line 1534) +* __fractunssqhi: Fixed-point fractional library routines. + (line 1532) +* __fractunssqqi: Fixed-point fractional library routines. + (line 1531) +* __fractunssqsi: Fixed-point fractional library routines. + (line 1533) +* __fractunssqti: Fixed-point fractional library routines. + (line 1535) +* __fractunstadi: Fixed-point fractional library routines. + (line 1560) +* __fractunstahi: Fixed-point fractional library routines. + (line 1558) +* __fractunstaqi: Fixed-point fractional library routines. + (line 1557) +* __fractunstasi: Fixed-point fractional library routines. + (line 1559) +* __fractunstati: Fixed-point fractional library routines. + (line 1562) +* __fractunstida: Fixed-point fractional library routines. + (line 1730) +* __fractunstidq: Fixed-point fractional library routines. + (line 1727) +* __fractunstiha: Fixed-point fractional library routines. + (line 1728) +* __fractunstihq: Fixed-point fractional library routines. + (line 1724) +* __fractunstiqq: Fixed-point fractional library routines. + (line 1723) +* __fractunstisa: Fixed-point fractional library routines. + (line 1729) +* __fractunstisq: Fixed-point fractional library routines. + (line 1725) +* __fractunstita: Fixed-point fractional library routines. + (line 1732) +* __fractunstiuda: Fixed-point fractional library routines. + (line 1746) +* __fractunstiudq: Fixed-point fractional library routines. + (line 1740) +* __fractunstiuha: Fixed-point fractional library routines. + (line 1742) +* __fractunstiuhq: Fixed-point fractional library routines. + (line 1736) +* __fractunstiuqq: Fixed-point fractional library routines. + (line 1734) +* __fractunstiusa: Fixed-point fractional library routines. + (line 1744) +* __fractunstiusq: Fixed-point fractional library routines. + (line 1738) +* __fractunstiuta: Fixed-point fractional library routines. + (line 1748) +* __fractunsudadi: Fixed-point fractional library routines. + (line 1622) +* __fractunsudahi: Fixed-point fractional library routines. + (line 1618) +* __fractunsudaqi: Fixed-point fractional library routines. + (line 1616) +* __fractunsudasi: Fixed-point fractional library routines. + (line 1620) +* __fractunsudati: Fixed-point fractional library routines. + (line 1624) +* __fractunsudqdi: Fixed-point fractional library routines. + (line 1596) +* __fractunsudqhi: Fixed-point fractional library routines. + (line 1592) +* __fractunsudqqi: Fixed-point fractional library routines. + (line 1590) +* __fractunsudqsi: Fixed-point fractional library routines. + (line 1594) +* __fractunsudqti: Fixed-point fractional library routines. + (line 1598) +* __fractunsuhadi: Fixed-point fractional library routines. + (line 1606) +* __fractunsuhahi: Fixed-point fractional library routines. + (line 1602) +* __fractunsuhaqi: Fixed-point fractional library routines. + (line 1600) +* __fractunsuhasi: Fixed-point fractional library routines. + (line 1604) +* __fractunsuhati: Fixed-point fractional library routines. + (line 1608) +* __fractunsuhqdi: Fixed-point fractional library routines. + (line 1576) +* __fractunsuhqhi: Fixed-point fractional library routines. + (line 1574) +* __fractunsuhqqi: Fixed-point fractional library routines. + (line 1573) +* __fractunsuhqsi: Fixed-point fractional library routines. + (line 1575) +* __fractunsuhqti: Fixed-point fractional library routines. + (line 1578) +* __fractunsuqqdi: Fixed-point fractional library routines. + (line 1570) +* __fractunsuqqhi: Fixed-point fractional library routines. + (line 1566) +* __fractunsuqqqi: Fixed-point fractional library routines. + (line 1564) +* __fractunsuqqsi: Fixed-point fractional library routines. + (line 1568) +* __fractunsuqqti: Fixed-point fractional library routines. + (line 1572) +* __fractunsusadi: Fixed-point fractional library routines. + (line 1612) +* __fractunsusahi: Fixed-point fractional library routines. + (line 1610) +* __fractunsusaqi: Fixed-point fractional library routines. + (line 1609) +* __fractunsusasi: Fixed-point fractional library routines. + (line 1611) +* __fractunsusati: Fixed-point fractional library routines. + (line 1614) +* __fractunsusqdi: Fixed-point fractional library routines. + (line 1586) +* __fractunsusqhi: Fixed-point fractional library routines. + (line 1582) +* __fractunsusqqi: Fixed-point fractional library routines. + (line 1580) +* __fractunsusqsi: Fixed-point fractional library routines. + (line 1584) +* __fractunsusqti: Fixed-point fractional library routines. + (line 1588) +* __fractunsutadi: Fixed-point fractional library routines. + (line 1632) +* __fractunsutahi: Fixed-point fractional library routines. + (line 1628) +* __fractunsutaqi: Fixed-point fractional library routines. + (line 1626) +* __fractunsutasi: Fixed-point fractional library routines. + (line 1630) +* __fractunsutati: Fixed-point fractional library routines. + (line 1634) +* __fractuqqda: Fixed-point fractional library routines. + (line 672) +* __fractuqqdf: Fixed-point fractional library routines. + (line 695) +* __fractuqqdi: Fixed-point fractional library routines. + (line 692) +* __fractuqqdq: Fixed-point fractional library routines. + (line 669) +* __fractuqqha: Fixed-point fractional library routines. + (line 670) +* __fractuqqhi: Fixed-point fractional library routines. + (line 690) +* __fractuqqhq: Fixed-point fractional library routines. + (line 666) +* __fractuqqqi: Fixed-point fractional library routines. + (line 689) +* __fractuqqqq: Fixed-point fractional library routines. + (line 665) +* __fractuqqsa: Fixed-point fractional library routines. + (line 671) +* __fractuqqsf: Fixed-point fractional library routines. + (line 694) +* __fractuqqsi: Fixed-point fractional library routines. + (line 691) +* __fractuqqsq: Fixed-point fractional library routines. + (line 667) +* __fractuqqta: Fixed-point fractional library routines. + (line 674) +* __fractuqqti: Fixed-point fractional library routines. + (line 693) +* __fractuqquda: Fixed-point fractional library routines. + (line 686) +* __fractuqqudq2: Fixed-point fractional library routines. + (line 680) +* __fractuqquha: Fixed-point fractional library routines. + (line 682) +* __fractuqquhq2: Fixed-point fractional library routines. + (line 676) +* __fractuqqusa: Fixed-point fractional library routines. + (line 684) +* __fractuqqusq2: Fixed-point fractional library routines. + (line 678) +* __fractuqquta: Fixed-point fractional library routines. + (line 688) +* __fractusada: Fixed-point fractional library routines. + (line 829) +* __fractusadf: Fixed-point fractional library routines. + (line 850) +* __fractusadi: Fixed-point fractional library routines. + (line 847) +* __fractusadq: Fixed-point fractional library routines. + (line 826) +* __fractusaha: Fixed-point fractional library routines. + (line 827) +* __fractusahi: Fixed-point fractional library routines. + (line 845) +* __fractusahq: Fixed-point fractional library routines. + (line 824) +* __fractusaqi: Fixed-point fractional library routines. + (line 844) +* __fractusaqq: Fixed-point fractional library routines. + (line 823) +* __fractusasa: Fixed-point fractional library routines. + (line 828) +* __fractusasf: Fixed-point fractional library routines. + (line 849) +* __fractusasi: Fixed-point fractional library routines. + (line 846) +* __fractusasq: Fixed-point fractional library routines. + (line 825) +* __fractusata: Fixed-point fractional library routines. + (line 830) +* __fractusati: Fixed-point fractional library routines. + (line 848) +* __fractusauda2: Fixed-point fractional library routines. + (line 841) +* __fractusaudq: Fixed-point fractional library routines. + (line 837) +* __fractusauha2: Fixed-point fractional library routines. + (line 839) +* __fractusauhq: Fixed-point fractional library routines. + (line 833) +* __fractusauqq: Fixed-point fractional library routines. + (line 832) +* __fractusausq: Fixed-point fractional library routines. + (line 835) +* __fractusauta2: Fixed-point fractional library routines. + (line 843) +* __fractusqda: Fixed-point fractional library routines. + (line 731) +* __fractusqdf: Fixed-point fractional library routines. + (line 754) +* __fractusqdi: Fixed-point fractional library routines. + (line 751) +* __fractusqdq: Fixed-point fractional library routines. + (line 728) +* __fractusqha: Fixed-point fractional library routines. + (line 729) +* __fractusqhi: Fixed-point fractional library routines. + (line 749) +* __fractusqhq: Fixed-point fractional library routines. + (line 725) +* __fractusqqi: Fixed-point fractional library routines. + (line 748) +* __fractusqqq: Fixed-point fractional library routines. + (line 724) +* __fractusqsa: Fixed-point fractional library routines. + (line 730) +* __fractusqsf: Fixed-point fractional library routines. + (line 753) +* __fractusqsi: Fixed-point fractional library routines. + (line 750) +* __fractusqsq: Fixed-point fractional library routines. + (line 726) +* __fractusqta: Fixed-point fractional library routines. + (line 733) +* __fractusqti: Fixed-point fractional library routines. + (line 752) +* __fractusquda: Fixed-point fractional library routines. + (line 745) +* __fractusqudq2: Fixed-point fractional library routines. + (line 739) +* __fractusquha: Fixed-point fractional library routines. + (line 741) +* __fractusquhq2: Fixed-point fractional library routines. + (line 737) +* __fractusquqq2: Fixed-point fractional library routines. + (line 735) +* __fractusqusa: Fixed-point fractional library routines. + (line 743) +* __fractusquta: Fixed-point fractional library routines. + (line 747) +* __fractutada: Fixed-point fractional library routines. + (line 893) +* __fractutadf: Fixed-point fractional library routines. + (line 918) +* __fractutadi: Fixed-point fractional library routines. + (line 914) +* __fractutadq: Fixed-point fractional library routines. + (line 888) +* __fractutaha: Fixed-point fractional library routines. + (line 890) +* __fractutahi: Fixed-point fractional library routines. + (line 912) +* __fractutahq: Fixed-point fractional library routines. + (line 884) +* __fractutaqi: Fixed-point fractional library routines. + (line 911) +* __fractutaqq: Fixed-point fractional library routines. + (line 883) +* __fractutasa: Fixed-point fractional library routines. + (line 891) +* __fractutasf: Fixed-point fractional library routines. + (line 917) +* __fractutasi: Fixed-point fractional library routines. + (line 913) +* __fractutasq: Fixed-point fractional library routines. + (line 886) +* __fractutata: Fixed-point fractional library routines. + (line 895) +* __fractutati: Fixed-point fractional library routines. + (line 916) +* __fractutauda2: Fixed-point fractional library routines. + (line 909) +* __fractutaudq: Fixed-point fractional library routines. + (line 903) +* __fractutauha2: Fixed-point fractional library routines. + (line 905) +* __fractutauhq: Fixed-point fractional library routines. + (line 899) +* __fractutauqq: Fixed-point fractional library routines. + (line 897) +* __fractutausa2: Fixed-point fractional library routines. + (line 907) +* __fractutausq: Fixed-point fractional library routines. + (line 901) +* __gedf2: Soft float library routines. + (line 206) +* __gesf2: Soft float library routines. + (line 205) +* __getf2: Soft float library routines. + (line 207) +* __gtdf2: Soft float library routines. + (line 224) +* __gtsf2: Soft float library routines. + (line 223) +* __gttf2: Soft float library routines. + (line 225) +* __ledf2: Soft float library routines. + (line 218) +* __lesf2: Soft float library routines. + (line 217) +* __letf2: Soft float library routines. + (line 219) +* __lshrdi3: Integer library routines. + (line 31) +* __lshrsi3: Integer library routines. + (line 30) +* __lshrti3: Integer library routines. + (line 32) +* __lshruda3: Fixed-point fractional library routines. + (line 390) +* __lshrudq3: Fixed-point fractional library routines. + (line 384) +* __lshruha3: Fixed-point fractional library routines. + (line 386) +* __lshruhq3: Fixed-point fractional library routines. + (line 380) +* __lshruqq3: Fixed-point fractional library routines. + (line 378) +* __lshrusa3: Fixed-point fractional library routines. + (line 388) +* __lshrusq3: Fixed-point fractional library routines. + (line 382) +* __lshruta3: Fixed-point fractional library routines. + (line 392) +* __ltdf2: Soft float library routines. + (line 212) +* __ltsf2: Soft float library routines. + (line 211) +* __lttf2: Soft float library routines. + (line 213) +* __main: Collect2. (line 15) +* __moddi3: Integer library routines. + (line 37) +* __modsi3: Integer library routines. + (line 36) +* __modti3: Integer library routines. + (line 38) +* __morestack_current_segment: Miscellaneous routines. + (line 46) +* __morestack_initial_sp: Miscellaneous routines. + (line 47) +* __morestack_segments: Miscellaneous routines. + (line 45) +* __mulda3: Fixed-point fractional library routines. + (line 171) +* __muldc3: Soft float library routines. + (line 241) +* __muldf3: Soft float library routines. + (line 40) +* __muldi3: Integer library routines. + (line 43) +* __muldq3: Fixed-point fractional library routines. + (line 159) +* __mulha3: Fixed-point fractional library routines. + (line 169) +* __mulhq3: Fixed-point fractional library routines. + (line 156) +* __mulqq3: Fixed-point fractional library routines. + (line 155) +* __mulsa3: Fixed-point fractional library routines. + (line 170) +* __mulsc3: Soft float library routines. + (line 239) +* __mulsf3: Soft float library routines. + (line 39) +* __mulsi3: Integer library routines. + (line 42) +* __mulsq3: Fixed-point fractional library routines. + (line 157) +* __multa3: Fixed-point fractional library routines. + (line 173) +* __multc3: Soft float library routines. + (line 243) +* __multf3: Soft float library routines. + (line 42) +* __multi3: Integer library routines. + (line 44) +* __muluda3: Fixed-point fractional library routines. + (line 179) +* __muludq3: Fixed-point fractional library routines. + (line 167) +* __muluha3: Fixed-point fractional library routines. + (line 175) +* __muluhq3: Fixed-point fractional library routines. + (line 163) +* __muluqq3: Fixed-point fractional library routines. + (line 161) +* __mulusa3: Fixed-point fractional library routines. + (line 177) +* __mulusq3: Fixed-point fractional library routines. + (line 165) +* __muluta3: Fixed-point fractional library routines. + (line 181) +* __mulvdi3: Integer library routines. + (line 115) +* __mulvsi3: Integer library routines. + (line 114) +* __mulxc3: Soft float library routines. + (line 245) +* __mulxf3: Soft float library routines. + (line 44) +* __nedf2: Soft float library routines. + (line 200) +* __negda2: Fixed-point fractional library routines. + (line 299) +* __negdf2: Soft float library routines. + (line 56) +* __negdi2: Integer library routines. + (line 47) +* __negdq2: Fixed-point fractional library routines. + (line 289) +* __negha2: Fixed-point fractional library routines. + (line 297) +* __neghq2: Fixed-point fractional library routines. + (line 287) +* __negqq2: Fixed-point fractional library routines. + (line 286) +* __negsa2: Fixed-point fractional library routines. + (line 298) +* __negsf2: Soft float library routines. + (line 55) +* __negsq2: Fixed-point fractional library routines. + (line 288) +* __negta2: Fixed-point fractional library routines. + (line 300) +* __negtf2: Soft float library routines. + (line 57) +* __negti2: Integer library routines. + (line 48) +* __neguda2: Fixed-point fractional library routines. + (line 305) +* __negudq2: Fixed-point fractional library routines. + (line 296) +* __neguha2: Fixed-point fractional library routines. + (line 302) +* __neguhq2: Fixed-point fractional library routines. + (line 292) +* __neguqq2: Fixed-point fractional library routines. + (line 291) +* __negusa2: Fixed-point fractional library routines. + (line 303) +* __negusq2: Fixed-point fractional library routines. + (line 294) +* __neguta2: Fixed-point fractional library routines. + (line 307) +* __negvdi2: Integer library routines. + (line 119) +* __negvsi2: Integer library routines. + (line 118) +* __negxf2: Soft float library routines. + (line 58) +* __nesf2: Soft float library routines. + (line 199) +* __netf2: Soft float library routines. + (line 201) +* __paritydi2: Integer library routines. + (line 151) +* __paritysi2: Integer library routines. + (line 150) +* __parityti2: Integer library routines. + (line 152) +* __popcountdi2: Integer library routines. + (line 157) +* __popcountsi2: Integer library routines. + (line 156) +* __popcountti2: Integer library routines. + (line 158) +* __powidf2: Soft float library routines. + (line 233) +* __powisf2: Soft float library routines. + (line 232) +* __powitf2: Soft float library routines. + (line 234) +* __powixf2: Soft float library routines. + (line 235) +* __satfractdadq: Fixed-point fractional library routines. + (line 1153) +* __satfractdaha2: Fixed-point fractional library routines. + (line 1154) +* __satfractdahq: Fixed-point fractional library routines. + (line 1151) +* __satfractdaqq: Fixed-point fractional library routines. + (line 1150) +* __satfractdasa2: Fixed-point fractional library routines. + (line 1155) +* __satfractdasq: Fixed-point fractional library routines. + (line 1152) +* __satfractdata2: Fixed-point fractional library routines. + (line 1156) +* __satfractdauda: Fixed-point fractional library routines. + (line 1166) +* __satfractdaudq: Fixed-point fractional library routines. + (line 1162) +* __satfractdauha: Fixed-point fractional library routines. + (line 1164) +* __satfractdauhq: Fixed-point fractional library routines. + (line 1159) +* __satfractdauqq: Fixed-point fractional library routines. + (line 1158) +* __satfractdausa: Fixed-point fractional library routines. + (line 1165) +* __satfractdausq: Fixed-point fractional library routines. + (line 1160) +* __satfractdauta: Fixed-point fractional library routines. + (line 1168) +* __satfractdfda: Fixed-point fractional library routines. + (line 1506) +* __satfractdfdq: Fixed-point fractional library routines. + (line 1503) +* __satfractdfha: Fixed-point fractional library routines. + (line 1504) +* __satfractdfhq: Fixed-point fractional library routines. + (line 1501) +* __satfractdfqq: Fixed-point fractional library routines. + (line 1500) +* __satfractdfsa: Fixed-point fractional library routines. + (line 1505) +* __satfractdfsq: Fixed-point fractional library routines. + (line 1502) +* __satfractdfta: Fixed-point fractional library routines. + (line 1507) +* __satfractdfuda: Fixed-point fractional library routines. + (line 1515) +* __satfractdfudq: Fixed-point fractional library routines. + (line 1512) +* __satfractdfuha: Fixed-point fractional library routines. + (line 1513) +* __satfractdfuhq: Fixed-point fractional library routines. + (line 1509) +* __satfractdfuqq: Fixed-point fractional library routines. + (line 1508) +* __satfractdfusa: Fixed-point fractional library routines. + (line 1514) +* __satfractdfusq: Fixed-point fractional library routines. + (line 1510) +* __satfractdfuta: Fixed-point fractional library routines. + (line 1517) +* __satfractdida: Fixed-point fractional library routines. + (line 1456) +* __satfractdidq: Fixed-point fractional library routines. + (line 1453) +* __satfractdiha: Fixed-point fractional library routines. + (line 1454) +* __satfractdihq: Fixed-point fractional library routines. + (line 1451) +* __satfractdiqq: Fixed-point fractional library routines. + (line 1450) +* __satfractdisa: Fixed-point fractional library routines. + (line 1455) +* __satfractdisq: Fixed-point fractional library routines. + (line 1452) +* __satfractdita: Fixed-point fractional library routines. + (line 1457) +* __satfractdiuda: Fixed-point fractional library routines. + (line 1464) +* __satfractdiudq: Fixed-point fractional library routines. + (line 1461) +* __satfractdiuha: Fixed-point fractional library routines. + (line 1462) +* __satfractdiuhq: Fixed-point fractional library routines. + (line 1459) +* __satfractdiuqq: Fixed-point fractional library routines. + (line 1458) +* __satfractdiusa: Fixed-point fractional library routines. + (line 1463) +* __satfractdiusq: Fixed-point fractional library routines. + (line 1460) +* __satfractdiuta: Fixed-point fractional library routines. + (line 1465) +* __satfractdqda: Fixed-point fractional library routines. + (line 1098) +* __satfractdqha: Fixed-point fractional library routines. + (line 1096) +* __satfractdqhq2: Fixed-point fractional library routines. + (line 1094) +* __satfractdqqq2: Fixed-point fractional library routines. + (line 1093) +* __satfractdqsa: Fixed-point fractional library routines. + (line 1097) +* __satfractdqsq2: Fixed-point fractional library routines. + (line 1095) +* __satfractdqta: Fixed-point fractional library routines. + (line 1099) +* __satfractdquda: Fixed-point fractional library routines. + (line 1111) +* __satfractdqudq: Fixed-point fractional library routines. + (line 1106) +* __satfractdquha: Fixed-point fractional library routines. + (line 1108) +* __satfractdquhq: Fixed-point fractional library routines. + (line 1102) +* __satfractdquqq: Fixed-point fractional library routines. + (line 1101) +* __satfractdqusa: Fixed-point fractional library routines. + (line 1109) +* __satfractdqusq: Fixed-point fractional library routines. + (line 1104) +* __satfractdquta: Fixed-point fractional library routines. + (line 1113) +* __satfracthada2: Fixed-point fractional library routines. + (line 1119) +* __satfracthadq: Fixed-point fractional library routines. + (line 1117) +* __satfracthahq: Fixed-point fractional library routines. + (line 1115) +* __satfracthaqq: Fixed-point fractional library routines. + (line 1114) +* __satfracthasa2: Fixed-point fractional library routines. + (line 1118) +* __satfracthasq: Fixed-point fractional library routines. + (line 1116) +* __satfracthata2: Fixed-point fractional library routines. + (line 1120) +* __satfracthauda: Fixed-point fractional library routines. + (line 1132) +* __satfracthaudq: Fixed-point fractional library routines. + (line 1127) +* __satfracthauha: Fixed-point fractional library routines. + (line 1129) +* __satfracthauhq: Fixed-point fractional library routines. + (line 1123) +* __satfracthauqq: Fixed-point fractional library routines. + (line 1122) +* __satfracthausa: Fixed-point fractional library routines. + (line 1130) +* __satfracthausq: Fixed-point fractional library routines. + (line 1125) +* __satfracthauta: Fixed-point fractional library routines. + (line 1134) +* __satfracthida: Fixed-point fractional library routines. + (line 1424) +* __satfracthidq: Fixed-point fractional library routines. + (line 1421) +* __satfracthiha: Fixed-point fractional library routines. + (line 1422) +* __satfracthihq: Fixed-point fractional library routines. + (line 1419) +* __satfracthiqq: Fixed-point fractional library routines. + (line 1418) +* __satfracthisa: Fixed-point fractional library routines. + (line 1423) +* __satfracthisq: Fixed-point fractional library routines. + (line 1420) +* __satfracthita: Fixed-point fractional library routines. + (line 1425) +* __satfracthiuda: Fixed-point fractional library routines. + (line 1432) +* __satfracthiudq: Fixed-point fractional library routines. + (line 1429) +* __satfracthiuha: Fixed-point fractional library routines. + (line 1430) +* __satfracthiuhq: Fixed-point fractional library routines. + (line 1427) +* __satfracthiuqq: Fixed-point fractional library routines. + (line 1426) +* __satfracthiusa: Fixed-point fractional library routines. + (line 1431) +* __satfracthiusq: Fixed-point fractional library routines. + (line 1428) +* __satfracthiuta: Fixed-point fractional library routines. + (line 1433) +* __satfracthqda: Fixed-point fractional library routines. + (line 1064) +* __satfracthqdq2: Fixed-point fractional library routines. + (line 1061) +* __satfracthqha: Fixed-point fractional library routines. + (line 1062) +* __satfracthqqq2: Fixed-point fractional library routines. + (line 1059) +* __satfracthqsa: Fixed-point fractional library routines. + (line 1063) +* __satfracthqsq2: Fixed-point fractional library routines. + (line 1060) +* __satfracthqta: Fixed-point fractional library routines. + (line 1065) +* __satfracthquda: Fixed-point fractional library routines. + (line 1072) +* __satfracthqudq: Fixed-point fractional library routines. + (line 1069) +* __satfracthquha: Fixed-point fractional library routines. + (line 1070) +* __satfracthquhq: Fixed-point fractional library routines. + (line 1067) +* __satfracthquqq: Fixed-point fractional library routines. + (line 1066) +* __satfracthqusa: Fixed-point fractional library routines. + (line 1071) +* __satfracthqusq: Fixed-point fractional library routines. + (line 1068) +* __satfracthquta: Fixed-point fractional library routines. + (line 1073) +* __satfractqida: Fixed-point fractional library routines. + (line 1402) +* __satfractqidq: Fixed-point fractional library routines. + (line 1399) +* __satfractqiha: Fixed-point fractional library routines. + (line 1400) +* __satfractqihq: Fixed-point fractional library routines. + (line 1397) +* __satfractqiqq: Fixed-point fractional library routines. + (line 1396) +* __satfractqisa: Fixed-point fractional library routines. + (line 1401) +* __satfractqisq: Fixed-point fractional library routines. + (line 1398) +* __satfractqita: Fixed-point fractional library routines. + (line 1403) +* __satfractqiuda: Fixed-point fractional library routines. + (line 1415) +* __satfractqiudq: Fixed-point fractional library routines. + (line 1410) +* __satfractqiuha: Fixed-point fractional library routines. + (line 1412) +* __satfractqiuhq: Fixed-point fractional library routines. + (line 1406) +* __satfractqiuqq: Fixed-point fractional library routines. + (line 1405) +* __satfractqiusa: Fixed-point fractional library routines. + (line 1413) +* __satfractqiusq: Fixed-point fractional library routines. + (line 1408) +* __satfractqiuta: Fixed-point fractional library routines. + (line 1417) +* __satfractqqda: Fixed-point fractional library routines. + (line 1043) +* __satfractqqdq2: Fixed-point fractional library routines. + (line 1040) +* __satfractqqha: Fixed-point fractional library routines. + (line 1041) +* __satfractqqhq2: Fixed-point fractional library routines. + (line 1038) +* __satfractqqsa: Fixed-point fractional library routines. + (line 1042) +* __satfractqqsq2: Fixed-point fractional library routines. + (line 1039) +* __satfractqqta: Fixed-point fractional library routines. + (line 1044) +* __satfractqquda: Fixed-point fractional library routines. + (line 1056) +* __satfractqqudq: Fixed-point fractional library routines. + (line 1051) +* __satfractqquha: Fixed-point fractional library routines. + (line 1053) +* __satfractqquhq: Fixed-point fractional library routines. + (line 1047) +* __satfractqquqq: Fixed-point fractional library routines. + (line 1046) +* __satfractqqusa: Fixed-point fractional library routines. + (line 1054) +* __satfractqqusq: Fixed-point fractional library routines. + (line 1049) +* __satfractqquta: Fixed-point fractional library routines. + (line 1058) +* __satfractsada2: Fixed-point fractional library routines. + (line 1140) +* __satfractsadq: Fixed-point fractional library routines. + (line 1138) +* __satfractsaha2: Fixed-point fractional library routines. + (line 1139) +* __satfractsahq: Fixed-point fractional library routines. + (line 1136) +* __satfractsaqq: Fixed-point fractional library routines. + (line 1135) +* __satfractsasq: Fixed-point fractional library routines. + (line 1137) +* __satfractsata2: Fixed-point fractional library routines. + (line 1141) +* __satfractsauda: Fixed-point fractional library routines. + (line 1148) +* __satfractsaudq: Fixed-point fractional library routines. + (line 1145) +* __satfractsauha: Fixed-point fractional library routines. + (line 1146) +* __satfractsauhq: Fixed-point fractional library routines. + (line 1143) +* __satfractsauqq: Fixed-point fractional library routines. + (line 1142) +* __satfractsausa: Fixed-point fractional library routines. + (line 1147) +* __satfractsausq: Fixed-point fractional library routines. + (line 1144) +* __satfractsauta: Fixed-point fractional library routines. + (line 1149) +* __satfractsfda: Fixed-point fractional library routines. + (line 1490) +* __satfractsfdq: Fixed-point fractional library routines. + (line 1487) +* __satfractsfha: Fixed-point fractional library routines. + (line 1488) +* __satfractsfhq: Fixed-point fractional library routines. + (line 1485) +* __satfractsfqq: Fixed-point fractional library routines. + (line 1484) +* __satfractsfsa: Fixed-point fractional library routines. + (line 1489) +* __satfractsfsq: Fixed-point fractional library routines. + (line 1486) +* __satfractsfta: Fixed-point fractional library routines. + (line 1491) +* __satfractsfuda: Fixed-point fractional library routines. + (line 1498) +* __satfractsfudq: Fixed-point fractional library routines. + (line 1495) +* __satfractsfuha: Fixed-point fractional library routines. + (line 1496) +* __satfractsfuhq: Fixed-point fractional library routines. + (line 1493) +* __satfractsfuqq: Fixed-point fractional library routines. + (line 1492) +* __satfractsfusa: Fixed-point fractional library routines. + (line 1497) +* __satfractsfusq: Fixed-point fractional library routines. + (line 1494) +* __satfractsfuta: Fixed-point fractional library routines. + (line 1499) +* __satfractsida: Fixed-point fractional library routines. + (line 1440) +* __satfractsidq: Fixed-point fractional library routines. + (line 1437) +* __satfractsiha: Fixed-point fractional library routines. + (line 1438) +* __satfractsihq: Fixed-point fractional library routines. + (line 1435) +* __satfractsiqq: Fixed-point fractional library routines. + (line 1434) +* __satfractsisa: Fixed-point fractional library routines. + (line 1439) +* __satfractsisq: Fixed-point fractional library routines. + (line 1436) +* __satfractsita: Fixed-point fractional library routines. + (line 1441) +* __satfractsiuda: Fixed-point fractional library routines. + (line 1448) +* __satfractsiudq: Fixed-point fractional library routines. + (line 1445) +* __satfractsiuha: Fixed-point fractional library routines. + (line 1446) +* __satfractsiuhq: Fixed-point fractional library routines. + (line 1443) +* __satfractsiuqq: Fixed-point fractional library routines. + (line 1442) +* __satfractsiusa: Fixed-point fractional library routines. + (line 1447) +* __satfractsiusq: Fixed-point fractional library routines. + (line 1444) +* __satfractsiuta: Fixed-point fractional library routines. + (line 1449) +* __satfractsqda: Fixed-point fractional library routines. + (line 1079) +* __satfractsqdq2: Fixed-point fractional library routines. + (line 1076) +* __satfractsqha: Fixed-point fractional library routines. + (line 1077) +* __satfractsqhq2: Fixed-point fractional library routines. + (line 1075) +* __satfractsqqq2: Fixed-point fractional library routines. + (line 1074) +* __satfractsqsa: Fixed-point fractional library routines. + (line 1078) +* __satfractsqta: Fixed-point fractional library routines. + (line 1080) +* __satfractsquda: Fixed-point fractional library routines. + (line 1090) +* __satfractsqudq: Fixed-point fractional library routines. + (line 1086) +* __satfractsquha: Fixed-point fractional library routines. + (line 1088) +* __satfractsquhq: Fixed-point fractional library routines. + (line 1083) +* __satfractsquqq: Fixed-point fractional library routines. + (line 1082) +* __satfractsqusa: Fixed-point fractional library routines. + (line 1089) +* __satfractsqusq: Fixed-point fractional library routines. + (line 1084) +* __satfractsquta: Fixed-point fractional library routines. + (line 1092) +* __satfracttada2: Fixed-point fractional library routines. + (line 1175) +* __satfracttadq: Fixed-point fractional library routines. + (line 1172) +* __satfracttaha2: Fixed-point fractional library routines. + (line 1173) +* __satfracttahq: Fixed-point fractional library routines. + (line 1170) +* __satfracttaqq: Fixed-point fractional library routines. + (line 1169) +* __satfracttasa2: Fixed-point fractional library routines. + (line 1174) +* __satfracttasq: Fixed-point fractional library routines. + (line 1171) +* __satfracttauda: Fixed-point fractional library routines. + (line 1187) +* __satfracttaudq: Fixed-point fractional library routines. + (line 1182) +* __satfracttauha: Fixed-point fractional library routines. + (line 1184) +* __satfracttauhq: Fixed-point fractional library routines. + (line 1178) +* __satfracttauqq: Fixed-point fractional library routines. + (line 1177) +* __satfracttausa: Fixed-point fractional library routines. + (line 1185) +* __satfracttausq: Fixed-point fractional library routines. + (line 1180) +* __satfracttauta: Fixed-point fractional library routines. + (line 1189) +* __satfracttida: Fixed-point fractional library routines. + (line 1472) +* __satfracttidq: Fixed-point fractional library routines. + (line 1469) +* __satfracttiha: Fixed-point fractional library routines. + (line 1470) +* __satfracttihq: Fixed-point fractional library routines. + (line 1467) +* __satfracttiqq: Fixed-point fractional library routines. + (line 1466) +* __satfracttisa: Fixed-point fractional library routines. + (line 1471) +* __satfracttisq: Fixed-point fractional library routines. + (line 1468) +* __satfracttita: Fixed-point fractional library routines. + (line 1473) +* __satfracttiuda: Fixed-point fractional library routines. + (line 1481) +* __satfracttiudq: Fixed-point fractional library routines. + (line 1478) +* __satfracttiuha: Fixed-point fractional library routines. + (line 1479) +* __satfracttiuhq: Fixed-point fractional library routines. + (line 1475) +* __satfracttiuqq: Fixed-point fractional library routines. + (line 1474) +* __satfracttiusa: Fixed-point fractional library routines. + (line 1480) +* __satfracttiusq: Fixed-point fractional library routines. + (line 1476) +* __satfracttiuta: Fixed-point fractional library routines. + (line 1483) +* __satfractudada: Fixed-point fractional library routines. + (line 1351) +* __satfractudadq: Fixed-point fractional library routines. + (line 1347) +* __satfractudaha: Fixed-point fractional library routines. + (line 1349) +* __satfractudahq: Fixed-point fractional library routines. + (line 1344) +* __satfractudaqq: Fixed-point fractional library routines. + (line 1343) +* __satfractudasa: Fixed-point fractional library routines. + (line 1350) +* __satfractudasq: Fixed-point fractional library routines. + (line 1345) +* __satfractudata: Fixed-point fractional library routines. + (line 1353) +* __satfractudaudq: Fixed-point fractional library routines. + (line 1361) +* __satfractudauha2: Fixed-point fractional library routines. + (line 1363) +* __satfractudauhq: Fixed-point fractional library routines. + (line 1357) +* __satfractudauqq: Fixed-point fractional library routines. + (line 1355) +* __satfractudausa2: Fixed-point fractional library routines. + (line 1365) +* __satfractudausq: Fixed-point fractional library routines. + (line 1359) +* __satfractudauta2: Fixed-point fractional library routines. + (line 1367) +* __satfractudqda: Fixed-point fractional library routines. + (line 1276) +* __satfractudqdq: Fixed-point fractional library routines. + (line 1271) +* __satfractudqha: Fixed-point fractional library routines. + (line 1273) +* __satfractudqhq: Fixed-point fractional library routines. + (line 1267) +* __satfractudqqq: Fixed-point fractional library routines. + (line 1266) +* __satfractudqsa: Fixed-point fractional library routines. + (line 1274) +* __satfractudqsq: Fixed-point fractional library routines. + (line 1269) +* __satfractudqta: Fixed-point fractional library routines. + (line 1278) +* __satfractudquda: Fixed-point fractional library routines. + (line 1290) +* __satfractudquha: Fixed-point fractional library routines. + (line 1286) +* __satfractudquhq2: Fixed-point fractional library routines. + (line 1282) +* __satfractudquqq2: Fixed-point fractional library routines. + (line 1280) +* __satfractudqusa: Fixed-point fractional library routines. + (line 1288) +* __satfractudqusq2: Fixed-point fractional library routines. + (line 1284) +* __satfractudquta: Fixed-point fractional library routines. + (line 1292) +* __satfractuhada: Fixed-point fractional library routines. + (line 1304) +* __satfractuhadq: Fixed-point fractional library routines. + (line 1299) +* __satfractuhaha: Fixed-point fractional library routines. + (line 1301) +* __satfractuhahq: Fixed-point fractional library routines. + (line 1295) +* __satfractuhaqq: Fixed-point fractional library routines. + (line 1294) +* __satfractuhasa: Fixed-point fractional library routines. + (line 1302) +* __satfractuhasq: Fixed-point fractional library routines. + (line 1297) +* __satfractuhata: Fixed-point fractional library routines. + (line 1306) +* __satfractuhauda2: Fixed-point fractional library routines. + (line 1318) +* __satfractuhaudq: Fixed-point fractional library routines. + (line 1314) +* __satfractuhauhq: Fixed-point fractional library routines. + (line 1310) +* __satfractuhauqq: Fixed-point fractional library routines. + (line 1308) +* __satfractuhausa2: Fixed-point fractional library routines. + (line 1316) +* __satfractuhausq: Fixed-point fractional library routines. + (line 1312) +* __satfractuhauta2: Fixed-point fractional library routines. + (line 1320) +* __satfractuhqda: Fixed-point fractional library routines. + (line 1224) +* __satfractuhqdq: Fixed-point fractional library routines. + (line 1221) +* __satfractuhqha: Fixed-point fractional library routines. + (line 1222) +* __satfractuhqhq: Fixed-point fractional library routines. + (line 1219) +* __satfractuhqqq: Fixed-point fractional library routines. + (line 1218) +* __satfractuhqsa: Fixed-point fractional library routines. + (line 1223) +* __satfractuhqsq: Fixed-point fractional library routines. + (line 1220) +* __satfractuhqta: Fixed-point fractional library routines. + (line 1225) +* __satfractuhquda: Fixed-point fractional library routines. + (line 1236) +* __satfractuhqudq2: Fixed-point fractional library routines. + (line 1231) +* __satfractuhquha: Fixed-point fractional library routines. + (line 1233) +* __satfractuhquqq2: Fixed-point fractional library routines. + (line 1227) +* __satfractuhqusa: Fixed-point fractional library routines. + (line 1234) +* __satfractuhqusq2: Fixed-point fractional library routines. + (line 1229) +* __satfractuhquta: Fixed-point fractional library routines. + (line 1238) +* __satfractunsdida: Fixed-point fractional library routines. + (line 1834) +* __satfractunsdidq: Fixed-point fractional library routines. + (line 1831) +* __satfractunsdiha: Fixed-point fractional library routines. + (line 1832) +* __satfractunsdihq: Fixed-point fractional library routines. + (line 1828) +* __satfractunsdiqq: Fixed-point fractional library routines. + (line 1827) +* __satfractunsdisa: Fixed-point fractional library routines. + (line 1833) +* __satfractunsdisq: Fixed-point fractional library routines. + (line 1829) +* __satfractunsdita: Fixed-point fractional library routines. + (line 1836) +* __satfractunsdiuda: Fixed-point fractional library routines. + (line 1850) +* __satfractunsdiudq: Fixed-point fractional library routines. + (line 1844) +* __satfractunsdiuha: Fixed-point fractional library routines. + (line 1846) +* __satfractunsdiuhq: Fixed-point fractional library routines. + (line 1840) +* __satfractunsdiuqq: Fixed-point fractional library routines. + (line 1838) +* __satfractunsdiusa: Fixed-point fractional library routines. + (line 1848) +* __satfractunsdiusq: Fixed-point fractional library routines. + (line 1842) +* __satfractunsdiuta: Fixed-point fractional library routines. + (line 1852) +* __satfractunshida: Fixed-point fractional library routines. + (line 1786) +* __satfractunshidq: Fixed-point fractional library routines. + (line 1783) +* __satfractunshiha: Fixed-point fractional library routines. + (line 1784) +* __satfractunshihq: Fixed-point fractional library routines. + (line 1780) +* __satfractunshiqq: Fixed-point fractional library routines. + (line 1779) +* __satfractunshisa: Fixed-point fractional library routines. + (line 1785) +* __satfractunshisq: Fixed-point fractional library routines. + (line 1781) +* __satfractunshita: Fixed-point fractional library routines. + (line 1788) +* __satfractunshiuda: Fixed-point fractional library routines. + (line 1802) +* __satfractunshiudq: Fixed-point fractional library routines. + (line 1796) +* __satfractunshiuha: Fixed-point fractional library routines. + (line 1798) +* __satfractunshiuhq: Fixed-point fractional library routines. + (line 1792) +* __satfractunshiuqq: Fixed-point fractional library routines. + (line 1790) +* __satfractunshiusa: Fixed-point fractional library routines. + (line 1800) +* __satfractunshiusq: Fixed-point fractional library routines. + (line 1794) +* __satfractunshiuta: Fixed-point fractional library routines. + (line 1804) +* __satfractunsqida: Fixed-point fractional library routines. + (line 1760) +* __satfractunsqidq: Fixed-point fractional library routines. + (line 1757) +* __satfractunsqiha: Fixed-point fractional library routines. + (line 1758) +* __satfractunsqihq: Fixed-point fractional library routines. + (line 1754) +* __satfractunsqiqq: Fixed-point fractional library routines. + (line 1753) +* __satfractunsqisa: Fixed-point fractional library routines. + (line 1759) +* __satfractunsqisq: Fixed-point fractional library routines. + (line 1755) +* __satfractunsqita: Fixed-point fractional library routines. + (line 1762) +* __satfractunsqiuda: Fixed-point fractional library routines. + (line 1776) +* __satfractunsqiudq: Fixed-point fractional library routines. + (line 1770) +* __satfractunsqiuha: Fixed-point fractional library routines. + (line 1772) +* __satfractunsqiuhq: Fixed-point fractional library routines. + (line 1766) +* __satfractunsqiuqq: Fixed-point fractional library routines. + (line 1764) +* __satfractunsqiusa: Fixed-point fractional library routines. + (line 1774) +* __satfractunsqiusq: Fixed-point fractional library routines. + (line 1768) +* __satfractunsqiuta: Fixed-point fractional library routines. + (line 1778) +* __satfractunssida: Fixed-point fractional library routines. + (line 1811) +* __satfractunssidq: Fixed-point fractional library routines. + (line 1808) +* __satfractunssiha: Fixed-point fractional library routines. + (line 1809) +* __satfractunssihq: Fixed-point fractional library routines. + (line 1806) +* __satfractunssiqq: Fixed-point fractional library routines. + (line 1805) +* __satfractunssisa: Fixed-point fractional library routines. + (line 1810) +* __satfractunssisq: Fixed-point fractional library routines. + (line 1807) +* __satfractunssita: Fixed-point fractional library routines. + (line 1812) +* __satfractunssiuda: Fixed-point fractional library routines. + (line 1824) +* __satfractunssiudq: Fixed-point fractional library routines. + (line 1819) +* __satfractunssiuha: Fixed-point fractional library routines. + (line 1821) +* __satfractunssiuhq: Fixed-point fractional library routines. + (line 1815) +* __satfractunssiuqq: Fixed-point fractional library routines. + (line 1814) +* __satfractunssiusa: Fixed-point fractional library routines. + (line 1822) +* __satfractunssiusq: Fixed-point fractional library routines. + (line 1817) +* __satfractunssiuta: Fixed-point fractional library routines. + (line 1826) +* __satfractunstida: Fixed-point fractional library routines. + (line 1864) +* __satfractunstidq: Fixed-point fractional library routines. + (line 1859) +* __satfractunstiha: Fixed-point fractional library routines. + (line 1861) +* __satfractunstihq: Fixed-point fractional library routines. + (line 1855) +* __satfractunstiqq: Fixed-point fractional library routines. + (line 1854) +* __satfractunstisa: Fixed-point fractional library routines. + (line 1862) +* __satfractunstisq: Fixed-point fractional library routines. + (line 1857) +* __satfractunstita: Fixed-point fractional library routines. + (line 1866) +* __satfractunstiuda: Fixed-point fractional library routines. + (line 1880) +* __satfractunstiudq: Fixed-point fractional library routines. + (line 1874) +* __satfractunstiuha: Fixed-point fractional library routines. + (line 1876) +* __satfractunstiuhq: Fixed-point fractional library routines. + (line 1870) +* __satfractunstiuqq: Fixed-point fractional library routines. + (line 1868) +* __satfractunstiusa: Fixed-point fractional library routines. + (line 1878) +* __satfractunstiusq: Fixed-point fractional library routines. + (line 1872) +* __satfractunstiuta: Fixed-point fractional library routines. + (line 1882) +* __satfractuqqda: Fixed-point fractional library routines. + (line 1201) +* __satfractuqqdq: Fixed-point fractional library routines. + (line 1196) +* __satfractuqqha: Fixed-point fractional library routines. + (line 1198) +* __satfractuqqhq: Fixed-point fractional library routines. + (line 1192) +* __satfractuqqqq: Fixed-point fractional library routines. + (line 1191) +* __satfractuqqsa: Fixed-point fractional library routines. + (line 1199) +* __satfractuqqsq: Fixed-point fractional library routines. + (line 1194) +* __satfractuqqta: Fixed-point fractional library routines. + (line 1203) +* __satfractuqquda: Fixed-point fractional library routines. + (line 1215) +* __satfractuqqudq2: Fixed-point fractional library routines. + (line 1209) +* __satfractuqquha: Fixed-point fractional library routines. + (line 1211) +* __satfractuqquhq2: Fixed-point fractional library routines. + (line 1205) +* __satfractuqqusa: Fixed-point fractional library routines. + (line 1213) +* __satfractuqqusq2: Fixed-point fractional library routines. + (line 1207) +* __satfractuqquta: Fixed-point fractional library routines. + (line 1217) +* __satfractusada: Fixed-point fractional library routines. + (line 1327) +* __satfractusadq: Fixed-point fractional library routines. + (line 1324) +* __satfractusaha: Fixed-point fractional library routines. + (line 1325) +* __satfractusahq: Fixed-point fractional library routines. + (line 1322) +* __satfractusaqq: Fixed-point fractional library routines. + (line 1321) +* __satfractusasa: Fixed-point fractional library routines. + (line 1326) +* __satfractusasq: Fixed-point fractional library routines. + (line 1323) +* __satfractusata: Fixed-point fractional library routines. + (line 1328) +* __satfractusauda2: Fixed-point fractional library routines. + (line 1339) +* __satfractusaudq: Fixed-point fractional library routines. + (line 1335) +* __satfractusauha2: Fixed-point fractional library routines. + (line 1337) +* __satfractusauhq: Fixed-point fractional library routines. + (line 1331) +* __satfractusauqq: Fixed-point fractional library routines. + (line 1330) +* __satfractusausq: Fixed-point fractional library routines. + (line 1333) +* __satfractusauta2: Fixed-point fractional library routines. + (line 1341) +* __satfractusqda: Fixed-point fractional library routines. + (line 1248) +* __satfractusqdq: Fixed-point fractional library routines. + (line 1244) +* __satfractusqha: Fixed-point fractional library routines. + (line 1246) +* __satfractusqhq: Fixed-point fractional library routines. + (line 1241) +* __satfractusqqq: Fixed-point fractional library routines. + (line 1240) +* __satfractusqsa: Fixed-point fractional library routines. + (line 1247) +* __satfractusqsq: Fixed-point fractional library routines. + (line 1242) +* __satfractusqta: Fixed-point fractional library routines. + (line 1250) +* __satfractusquda: Fixed-point fractional library routines. + (line 1262) +* __satfractusqudq2: Fixed-point fractional library routines. + (line 1256) +* __satfractusquha: Fixed-point fractional library routines. + (line 1258) +* __satfractusquhq2: Fixed-point fractional library routines. + (line 1254) +* __satfractusquqq2: Fixed-point fractional library routines. + (line 1252) +* __satfractusqusa: Fixed-point fractional library routines. + (line 1260) +* __satfractusquta: Fixed-point fractional library routines. + (line 1264) +* __satfractutada: Fixed-point fractional library routines. + (line 1379) +* __satfractutadq: Fixed-point fractional library routines. + (line 1374) +* __satfractutaha: Fixed-point fractional library routines. + (line 1376) +* __satfractutahq: Fixed-point fractional library routines. + (line 1370) +* __satfractutaqq: Fixed-point fractional library routines. + (line 1369) +* __satfractutasa: Fixed-point fractional library routines. + (line 1377) +* __satfractutasq: Fixed-point fractional library routines. + (line 1372) +* __satfractutata: Fixed-point fractional library routines. + (line 1381) +* __satfractutauda2: Fixed-point fractional library routines. + (line 1395) +* __satfractutaudq: Fixed-point fractional library routines. + (line 1389) +* __satfractutauha2: Fixed-point fractional library routines. + (line 1391) +* __satfractutauhq: Fixed-point fractional library routines. + (line 1385) +* __satfractutauqq: Fixed-point fractional library routines. + (line 1383) +* __satfractutausa2: Fixed-point fractional library routines. + (line 1393) +* __satfractutausq: Fixed-point fractional library routines. + (line 1387) +* __splitstack_find: Miscellaneous routines. + (line 18) +* __ssaddda3: Fixed-point fractional library routines. + (line 67) +* __ssadddq3: Fixed-point fractional library routines. + (line 63) +* __ssaddha3: Fixed-point fractional library routines. + (line 65) +* __ssaddhq3: Fixed-point fractional library routines. + (line 60) +* __ssaddqq3: Fixed-point fractional library routines. + (line 59) +* __ssaddsa3: Fixed-point fractional library routines. + (line 66) +* __ssaddsq3: Fixed-point fractional library routines. + (line 61) +* __ssaddta3: Fixed-point fractional library routines. + (line 69) +* __ssashlda3: Fixed-point fractional library routines. + (line 402) +* __ssashldq3: Fixed-point fractional library routines. + (line 399) +* __ssashlha3: Fixed-point fractional library routines. + (line 400) +* __ssashlhq3: Fixed-point fractional library routines. + (line 396) +* __ssashlsa3: Fixed-point fractional library routines. + (line 401) +* __ssashlsq3: Fixed-point fractional library routines. + (line 397) +* __ssashlta3: Fixed-point fractional library routines. + (line 404) +* __ssdivda3: Fixed-point fractional library routines. + (line 261) +* __ssdivdq3: Fixed-point fractional library routines. + (line 257) +* __ssdivha3: Fixed-point fractional library routines. + (line 259) +* __ssdivhq3: Fixed-point fractional library routines. + (line 254) +* __ssdivqq3: Fixed-point fractional library routines. + (line 253) +* __ssdivsa3: Fixed-point fractional library routines. + (line 260) +* __ssdivsq3: Fixed-point fractional library routines. + (line 255) +* __ssdivta3: Fixed-point fractional library routines. + (line 263) +* __ssmulda3: Fixed-point fractional library routines. + (line 193) +* __ssmuldq3: Fixed-point fractional library routines. + (line 189) +* __ssmulha3: Fixed-point fractional library routines. + (line 191) +* __ssmulhq3: Fixed-point fractional library routines. + (line 186) +* __ssmulqq3: Fixed-point fractional library routines. + (line 185) +* __ssmulsa3: Fixed-point fractional library routines. + (line 192) +* __ssmulsq3: Fixed-point fractional library routines. + (line 187) +* __ssmulta3: Fixed-point fractional library routines. + (line 195) +* __ssnegda2: Fixed-point fractional library routines. + (line 316) +* __ssnegdq2: Fixed-point fractional library routines. + (line 313) +* __ssnegha2: Fixed-point fractional library routines. + (line 314) +* __ssneghq2: Fixed-point fractional library routines. + (line 311) +* __ssnegqq2: Fixed-point fractional library routines. + (line 310) +* __ssnegsa2: Fixed-point fractional library routines. + (line 315) +* __ssnegsq2: Fixed-point fractional library routines. + (line 312) +* __ssnegta2: Fixed-point fractional library routines. + (line 317) +* __sssubda3: Fixed-point fractional library routines. + (line 129) +* __sssubdq3: Fixed-point fractional library routines. + (line 125) +* __sssubha3: Fixed-point fractional library routines. + (line 127) +* __sssubhq3: Fixed-point fractional library routines. + (line 122) +* __sssubqq3: Fixed-point fractional library routines. + (line 121) +* __sssubsa3: Fixed-point fractional library routines. + (line 128) +* __sssubsq3: Fixed-point fractional library routines. + (line 123) +* __sssubta3: Fixed-point fractional library routines. + (line 131) +* __subda3: Fixed-point fractional library routines. + (line 107) +* __subdf3: Soft float library routines. + (line 31) +* __subdq3: Fixed-point fractional library routines. + (line 95) +* __subha3: Fixed-point fractional library routines. + (line 105) +* __subhq3: Fixed-point fractional library routines. + (line 92) +* __subqq3: Fixed-point fractional library routines. + (line 91) +* __subsa3: Fixed-point fractional library routines. + (line 106) +* __subsf3: Soft float library routines. + (line 30) +* __subsq3: Fixed-point fractional library routines. + (line 93) +* __subta3: Fixed-point fractional library routines. + (line 109) +* __subtf3: Soft float library routines. + (line 33) +* __subuda3: Fixed-point fractional library routines. + (line 115) +* __subudq3: Fixed-point fractional library routines. + (line 103) +* __subuha3: Fixed-point fractional library routines. + (line 111) +* __subuhq3: Fixed-point fractional library routines. + (line 99) +* __subuqq3: Fixed-point fractional library routines. + (line 97) +* __subusa3: Fixed-point fractional library routines. + (line 113) +* __subusq3: Fixed-point fractional library routines. + (line 101) +* __subuta3: Fixed-point fractional library routines. + (line 117) +* __subvdi3: Integer library routines. + (line 123) +* __subvsi3: Integer library routines. + (line 122) +* __subxf3: Soft float library routines. + (line 35) +* __truncdfsf2: Soft float library routines. + (line 76) +* __trunctfdf2: Soft float library routines. + (line 73) +* __trunctfsf2: Soft float library routines. + (line 75) +* __truncxfdf2: Soft float library routines. + (line 72) +* __truncxfsf2: Soft float library routines. + (line 74) +* __ucmpdi2: Integer library routines. + (line 93) +* __ucmpti2: Integer library routines. + (line 95) +* __udivdi3: Integer library routines. + (line 54) +* __udivmoddi3: Integer library routines. + (line 61) +* __udivsi3: Integer library routines. + (line 52) +* __udivti3: Integer library routines. + (line 63) +* __udivuda3: Fixed-point fractional library routines. + (line 246) +* __udivudq3: Fixed-point fractional library routines. + (line 240) +* __udivuha3: Fixed-point fractional library routines. + (line 242) +* __udivuhq3: Fixed-point fractional library routines. + (line 236) +* __udivuqq3: Fixed-point fractional library routines. + (line 234) +* __udivusa3: Fixed-point fractional library routines. + (line 244) +* __udivusq3: Fixed-point fractional library routines. + (line 238) +* __udivuta3: Fixed-point fractional library routines. + (line 248) +* __umoddi3: Integer library routines. + (line 71) +* __umodsi3: Integer library routines. + (line 69) +* __umodti3: Integer library routines. + (line 73) +* __unorddf2: Soft float library routines. + (line 173) +* __unordsf2: Soft float library routines. + (line 172) +* __unordtf2: Soft float library routines. + (line 174) +* __usadduda3: Fixed-point fractional library routines. + (line 85) +* __usaddudq3: Fixed-point fractional library routines. + (line 79) +* __usadduha3: Fixed-point fractional library routines. + (line 81) +* __usadduhq3: Fixed-point fractional library routines. + (line 75) +* __usadduqq3: Fixed-point fractional library routines. + (line 73) +* __usaddusa3: Fixed-point fractional library routines. + (line 83) +* __usaddusq3: Fixed-point fractional library routines. + (line 77) +* __usadduta3: Fixed-point fractional library routines. + (line 87) +* __usashluda3: Fixed-point fractional library routines. + (line 421) +* __usashludq3: Fixed-point fractional library routines. + (line 415) +* __usashluha3: Fixed-point fractional library routines. + (line 417) +* __usashluhq3: Fixed-point fractional library routines. + (line 411) +* __usashluqq3: Fixed-point fractional library routines. + (line 409) +* __usashlusa3: Fixed-point fractional library routines. + (line 419) +* __usashlusq3: Fixed-point fractional library routines. + (line 413) +* __usashluta3: Fixed-point fractional library routines. + (line 423) +* __usdivuda3: Fixed-point fractional library routines. + (line 280) +* __usdivudq3: Fixed-point fractional library routines. + (line 274) +* __usdivuha3: Fixed-point fractional library routines. + (line 276) +* __usdivuhq3: Fixed-point fractional library routines. + (line 270) +* __usdivuqq3: Fixed-point fractional library routines. + (line 268) +* __usdivusa3: Fixed-point fractional library routines. + (line 278) +* __usdivusq3: Fixed-point fractional library routines. + (line 272) +* __usdivuta3: Fixed-point fractional library routines. + (line 282) +* __usmuluda3: Fixed-point fractional library routines. + (line 212) +* __usmuludq3: Fixed-point fractional library routines. + (line 206) +* __usmuluha3: Fixed-point fractional library routines. + (line 208) +* __usmuluhq3: Fixed-point fractional library routines. + (line 202) +* __usmuluqq3: Fixed-point fractional library routines. + (line 200) +* __usmulusa3: Fixed-point fractional library routines. + (line 210) +* __usmulusq3: Fixed-point fractional library routines. + (line 204) +* __usmuluta3: Fixed-point fractional library routines. + (line 214) +* __usneguda2: Fixed-point fractional library routines. + (line 331) +* __usnegudq2: Fixed-point fractional library routines. + (line 326) +* __usneguha2: Fixed-point fractional library routines. + (line 328) +* __usneguhq2: Fixed-point fractional library routines. + (line 322) +* __usneguqq2: Fixed-point fractional library routines. + (line 321) +* __usnegusa2: Fixed-point fractional library routines. + (line 329) +* __usnegusq2: Fixed-point fractional library routines. + (line 324) +* __usneguta2: Fixed-point fractional library routines. + (line 333) +* __ussubuda3: Fixed-point fractional library routines. + (line 148) +* __ussubudq3: Fixed-point fractional library routines. + (line 142) +* __ussubuha3: Fixed-point fractional library routines. + (line 144) +* __ussubuhq3: Fixed-point fractional library routines. + (line 138) +* __ussubuqq3: Fixed-point fractional library routines. + (line 136) +* __ussubusa3: Fixed-point fractional library routines. + (line 146) +* __ussubusq3: Fixed-point fractional library routines. + (line 140) +* __ussubuta3: Fixed-point fractional library routines. + (line 150) +* abort: Portability. (line 21) +* abs: Arithmetic. (line 200) +* abs and attributes: Expressions. (line 64) +* ABS_EXPR: Unary and Binary Expressions. + (line 6) +* absence_set: Processor pipeline description. + (line 220) +* absM2 instruction pattern: Standard Names. (line 479) +* absolute value: Arithmetic. (line 200) +* access to operands: Accessors. (line 6) +* access to special operands: Special Accessors. (line 6) +* accessors: Accessors. (line 6) +* ACCUM_TYPE_SIZE: Type Layout. (line 88) +* ACCUMULATE_OUTGOING_ARGS: Stack Arguments. (line 49) +* ACCUMULATE_OUTGOING_ARGS and stack frames: Function Entry. (line 135) +* ADA_LONG_TYPE_SIZE: Type Layout. (line 26) +* Adding a new GIMPLE statement code: Adding a new GIMPLE statement code. + (line 6) +* ADDITIONAL_REGISTER_NAMES: Instruction Output. (line 15) +* addM3 instruction pattern: Standard Names. (line 216) +* addMODEcc instruction pattern: Standard Names. (line 917) +* addr_diff_vec: Side Effects. (line 302) +* addr_diff_vec, length of: Insn Lengths. (line 26) +* ADDR_EXPR: Storage References. (line 6) +* addr_vec: Side Effects. (line 297) +* addr_vec, length of: Insn Lengths. (line 26) +* address constraints: Simple Constraints. (line 164) +* address_operand <1>: Machine-Independent Predicates. + (line 63) +* address_operand: Simple Constraints. (line 168) +* addressing modes: Addressing Modes. (line 6) +* ADJUST_FIELD_ALIGN: Storage Layout. (line 189) +* ADJUST_INSN_LENGTH: Insn Lengths. (line 35) +* ADJUST_REG_ALLOC_ORDER: Allocation Order. (line 23) +* aggregates as return values: Aggregate Return. (line 6) +* alias: Alias analysis. (line 6) +* ALL_COP_ADDITIONAL_REGISTER_NAMES: MIPS Coprocessors. (line 32) +* ALL_REGS: Register Classes. (line 17) +* allocate_stack instruction pattern: Standard Names. (line 1227) +* alternate entry points: Insns. (line 140) +* anchored addresses: Anchored Addresses. (line 6) +* and: Arithmetic. (line 158) +* and and attributes: Expressions. (line 50) +* and, canonicalization of: Insn Canonicalizations. + (line 52) +* andM3 instruction pattern: Standard Names. (line 222) +* annotations: Annotations. (line 6) +* APPLY_RESULT_SIZE: Scalar Return. (line 112) +* ARG_POINTER_CFA_OFFSET: Frame Layout. (line 194) +* ARG_POINTER_REGNUM: Frame Registers. (line 41) +* ARG_POINTER_REGNUM and virtual registers: Regs and Memory. (line 65) +* arg_pointer_rtx: Frame Registers. (line 104) +* ARGS_GROW_DOWNWARD: Frame Layout. (line 35) +* argument passing: Interface. (line 36) +* arguments in registers: Register Arguments. (line 6) +* arguments on stack: Stack Arguments. (line 6) +* arithmetic library: Soft float library routines. + (line 6) +* arithmetic shift: Arithmetic. (line 173) +* arithmetic shift with signed saturation: Arithmetic. (line 173) +* arithmetic shift with unsigned saturation: Arithmetic. (line 173) +* arithmetic, in RTL: Arithmetic. (line 6) +* ARITHMETIC_TYPE_P: Types for C++. (line 61) +* array: Types. (line 6) +* ARRAY_RANGE_REF: Storage References. (line 6) +* ARRAY_REF: Storage References. (line 6) +* ARRAY_TYPE: Types. (line 6) +* AS_NEEDS_DASH_FOR_PIPED_INPUT: Driver. (line 89) +* ashift: Arithmetic. (line 173) +* ashift and attributes: Expressions. (line 64) +* ashiftrt: Arithmetic. (line 190) +* ashiftrt and attributes: Expressions. (line 64) +* ashlM3 instruction pattern: Standard Names. (line 458) +* ashrM3 instruction pattern: Standard Names. (line 468) +* ASM_APP_OFF: File Framework. (line 78) +* ASM_APP_ON: File Framework. (line 71) +* ASM_COMMENT_START: File Framework. (line 66) +* ASM_DECLARE_CLASS_REFERENCE: Label Output. (line 465) +* ASM_DECLARE_FUNCTION_NAME: Label Output. (line 99) +* ASM_DECLARE_FUNCTION_SIZE: Label Output. (line 114) +* ASM_DECLARE_OBJECT_NAME: Label Output. (line 127) +* ASM_DECLARE_REGISTER_GLOBAL: Label Output. (line 156) +* ASM_DECLARE_UNRESOLVED_REFERENCE: Label Output. (line 471) +* ASM_FINAL_SPEC: Driver. (line 82) +* ASM_FINISH_DECLARE_OBJECT: Label Output. (line 164) +* ASM_FORMAT_PRIVATE_NAME: Label Output. (line 383) +* asm_fprintf: Instruction Output. (line 151) +* ASM_FPRINTF_EXTENSIONS: Instruction Output. (line 162) +* ASM_GENERATE_INTERNAL_LABEL: Label Output. (line 367) +* asm_input: Side Effects. (line 284) +* asm_input and /v: Flags. (line 94) +* ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX: Exception Handling. (line 82) +* ASM_NO_SKIP_IN_TEXT: Alignment Output. (line 79) +* asm_noperands: Insns. (line 307) +* asm_operands and /v: Flags. (line 94) +* asm_operands, RTL sharing: Sharing. (line 45) +* asm_operands, usage: Assembler. (line 6) +* ASM_OUTPUT_ADDR_DIFF_ELT: Dispatch Tables. (line 9) +* ASM_OUTPUT_ADDR_VEC_ELT: Dispatch Tables. (line 26) +* ASM_OUTPUT_ALIGN: Alignment Output. (line 86) +* ASM_OUTPUT_ALIGN_WITH_NOP: Alignment Output. (line 91) +* ASM_OUTPUT_ALIGNED_BSS: Uninitialized Data. (line 71) +* ASM_OUTPUT_ALIGNED_COMMON: Uninitialized Data. (line 30) +* ASM_OUTPUT_ALIGNED_DECL_COMMON: Uninitialized Data. (line 38) +* ASM_OUTPUT_ALIGNED_DECL_LOCAL: Uninitialized Data. (line 102) +* ASM_OUTPUT_ALIGNED_LOCAL: Uninitialized Data. (line 94) +* ASM_OUTPUT_ASCII: Data Output. (line 62) +* ASM_OUTPUT_BSS: Uninitialized Data. (line 46) +* ASM_OUTPUT_CASE_END: Dispatch Tables. (line 51) +* ASM_OUTPUT_CASE_LABEL: Dispatch Tables. (line 38) +* ASM_OUTPUT_COMMON: Uninitialized Data. (line 10) +* ASM_OUTPUT_DEBUG_LABEL: Label Output. (line 355) +* ASM_OUTPUT_DEF: Label Output. (line 404) +* ASM_OUTPUT_DEF_FROM_DECLS: Label Output. (line 412) +* ASM_OUTPUT_DWARF_DELTA: SDB and DWARF. (line 69) +* ASM_OUTPUT_DWARF_OFFSET: SDB and DWARF. (line 78) +* ASM_OUTPUT_DWARF_PCREL: SDB and DWARF. (line 84) +* ASM_OUTPUT_DWARF_TABLE_REF: SDB and DWARF. (line 89) +* ASM_OUTPUT_DWARF_VMS_DELTA: SDB and DWARF. (line 73) +* ASM_OUTPUT_EXTERNAL: Label Output. (line 284) +* ASM_OUTPUT_FDESC: Data Output. (line 71) +* ASM_OUTPUT_FUNCTION_LABEL: Label Output. (line 17) +* ASM_OUTPUT_IDENT: File Framework. (line 109) +* ASM_OUTPUT_INTERNAL_LABEL: Label Output. (line 29) +* ASM_OUTPUT_LABEL: Label Output. (line 9) +* ASM_OUTPUT_LABEL_REF: Label Output. (line 328) +* ASM_OUTPUT_LABELREF: Label Output. (line 306) +* ASM_OUTPUT_LOCAL: Uninitialized Data. (line 81) +* ASM_OUTPUT_MAX_SKIP_ALIGN: Alignment Output. (line 95) +* ASM_OUTPUT_MEASURED_SIZE: Label Output. (line 53) +* ASM_OUTPUT_OPCODE: Instruction Output. (line 36) +* ASM_OUTPUT_POOL_EPILOGUE: Data Output. (line 121) +* ASM_OUTPUT_POOL_PROLOGUE: Data Output. (line 84) +* ASM_OUTPUT_REG_POP: Instruction Output. (line 206) +* ASM_OUTPUT_REG_PUSH: Instruction Output. (line 201) +* ASM_OUTPUT_SIZE_DIRECTIVE: Label Output. (line 47) +* ASM_OUTPUT_SKIP: Alignment Output. (line 73) +* ASM_OUTPUT_SOURCE_FILENAME: File Framework. (line 85) +* ASM_OUTPUT_SPECIAL_POOL_ENTRY: Data Output. (line 96) +* ASM_OUTPUT_SYMBOL_REF: Label Output. (line 321) +* ASM_OUTPUT_TYPE_DIRECTIVE: Label Output. (line 89) +* ASM_OUTPUT_WEAK_ALIAS: Label Output. (line 430) +* ASM_OUTPUT_WEAKREF: Label Output. (line 216) +* ASM_PREFERRED_EH_DATA_FORMAT: Exception Handling. (line 67) +* ASM_SPEC: Driver. (line 74) +* ASM_STABD_OP: DBX Options. (line 36) +* ASM_STABN_OP: DBX Options. (line 43) +* ASM_STABS_OP: DBX Options. (line 29) +* ASM_WEAKEN_DECL: Label Output. (line 208) +* ASM_WEAKEN_LABEL: Label Output. (line 195) +* assemble_name: Label Output. (line 8) +* assemble_name_raw: Label Output. (line 28) +* assembler format: File Framework. (line 6) +* assembler instructions in RTL: Assembler. (line 6) +* ASSEMBLER_DIALECT: Instruction Output. (line 174) +* assigning attribute values to insns: Tagging Insns. (line 6) +* asterisk in template: Output Statement. (line 29) +* atan2M3 instruction pattern: Standard Names. (line 549) +* attr <1>: Expressions. (line 154) +* attr: Tagging Insns. (line 54) +* attr_flag: Expressions. (line 119) +* attribute expressions: Expressions. (line 6) +* attribute specifications: Attr Example. (line 6) +* attribute specifications example: Attr Example. (line 6) +* ATTRIBUTE_ALIGNED_VALUE: Storage Layout. (line 171) +* attributes: Attributes. (line 6) +* attributes, defining: Defining Attributes. + (line 6) +* attributes, target-specific: Target Attributes. (line 6) +* autoincrement addressing, availability: Portability. (line 21) +* autoincrement/decrement addressing: Simple Constraints. (line 30) +* automata_option: Processor pipeline description. + (line 301) +* automaton based pipeline description: Processor pipeline description. + (line 6) +* automaton based scheduler: Processor pipeline description. + (line 6) +* AVOID_CCMODE_COPIES: Values in Registers. + (line 153) +* backslash: Output Template. (line 46) +* barrier: Insns. (line 160) +* barrier and /f: Flags. (line 125) +* barrier and /v: Flags. (line 44) +* BASE_REG_CLASS: Register Classes. (line 109) +* basic block: Basic Blocks. (line 6) +* Basic Statements: Basic Statements. (line 6) +* basic-block.h: Control Flow. (line 6) +* BASIC_BLOCK: Basic Blocks. (line 19) +* basic_block: Basic Blocks. (line 6) +* BB_HEAD, BB_END: Maintaining the CFG. + (line 88) +* bb_seq: GIMPLE sequences. (line 73) +* BIGGEST_ALIGNMENT: Storage Layout. (line 161) +* BIGGEST_FIELD_ALIGNMENT: Storage Layout. (line 182) +* BImode: Machine Modes. (line 22) +* BIND_EXPR: Unary and Binary Expressions. + (line 6) +* BINFO_TYPE: Classes. (line 6) +* bit-fields: Bit-Fields. (line 6) +* BIT_AND_EXPR: Unary and Binary Expressions. + (line 6) +* BIT_IOR_EXPR: Unary and Binary Expressions. + (line 6) +* BIT_NOT_EXPR: Unary and Binary Expressions. + (line 6) +* BIT_XOR_EXPR: Unary and Binary Expressions. + (line 6) +* BITFIELD_NBYTES_LIMITED: Storage Layout. (line 379) +* BITS_BIG_ENDIAN: Storage Layout. (line 12) +* BITS_BIG_ENDIAN, effect on sign_extract: Bit-Fields. (line 8) +* BITS_PER_UNIT: Storage Layout. (line 45) +* BITS_PER_WORD: Storage Layout. (line 50) +* bitwise complement: Arithmetic. (line 154) +* bitwise exclusive-or: Arithmetic. (line 168) +* bitwise inclusive-or: Arithmetic. (line 163) +* bitwise logical-and: Arithmetic. (line 158) +* BLKmode: Machine Modes. (line 183) +* BLKmode, and function return values: Calls. (line 23) +* block statement iterators <1>: Maintaining the CFG. + (line 45) +* block statement iterators: Basic Blocks. (line 68) +* BLOCK_FOR_INSN, bb_for_stmt: Maintaining the CFG. + (line 40) +* BLOCK_REG_PADDING: Register Arguments. (line 228) +* blockage instruction pattern: Standard Names. (line 1417) +* Blocks: Blocks. (line 6) +* bool: Misc. (line 854) +* BOOL_TYPE_SIZE: Type Layout. (line 44) +* BOOLEAN_TYPE: Types. (line 6) +* branch prediction: Profile information. + (line 24) +* BRANCH_COST: Costs. (line 105) +* break_out_memory_refs: Addressing Modes. (line 135) +* BREAK_STMT: Statements for C++. (line 6) +* bsi_commit_edge_inserts: Maintaining the CFG. + (line 118) +* bsi_end_p: Maintaining the CFG. + (line 60) +* bsi_insert_after: Maintaining the CFG. + (line 72) +* bsi_insert_before: Maintaining the CFG. + (line 78) +* bsi_insert_on_edge: Maintaining the CFG. + (line 118) +* bsi_last: Maintaining the CFG. + (line 56) +* bsi_next: Maintaining the CFG. + (line 64) +* bsi_prev: Maintaining the CFG. + (line 68) +* bsi_remove: Maintaining the CFG. + (line 84) +* bsi_start: Maintaining the CFG. + (line 52) +* BSS_SECTION_ASM_OP: Sections. (line 68) +* bswap: Arithmetic. (line 241) +* btruncM2 instruction pattern: Standard Names. (line 567) +* build0: Macros and Functions. + (line 16) +* build1: Macros and Functions. + (line 17) +* build2: Macros and Functions. + (line 18) +* build3: Macros and Functions. + (line 19) +* build4: Macros and Functions. + (line 20) +* build5: Macros and Functions. + (line 21) +* build6: Macros and Functions. + (line 22) +* builtin_longjmp instruction pattern: Standard Names. (line 1320) +* builtin_setjmp_receiver instruction pattern: Standard Names. + (line 1310) +* builtin_setjmp_setup instruction pattern: Standard Names. (line 1299) +* byte_mode: Machine Modes. (line 336) +* BYTES_BIG_ENDIAN: Storage Layout. (line 24) +* BYTES_BIG_ENDIAN, effect on subreg: Regs and Memory. (line 221) +* C statements for assembler output: Output Statement. (line 6) +* C99 math functions, implicit usage: Library Calls. (line 62) +* C_COMMON_OVERRIDE_OPTIONS: Run-time Target. (line 142) +* c_register_pragma: Misc. (line 404) +* c_register_pragma_with_expansion: Misc. (line 406) +* call <1>: Side Effects. (line 86) +* call: Flags. (line 239) +* call instruction pattern: Standard Names. (line 974) +* call usage: Calls. (line 10) +* call, in call_insn: Flags. (line 33) +* call, in mem: Flags. (line 99) +* call-clobbered register: Register Basics. (line 35) +* call-saved register: Register Basics. (line 46) +* call-used register: Register Basics. (line 53) +* CALL_EXPR: Unary and Binary Expressions. + (line 6) +* call_insn: Insns. (line 95) +* call_insn and /c: Flags. (line 33) +* call_insn and /f: Flags. (line 125) +* call_insn and /i: Flags. (line 24) +* call_insn and /j: Flags. (line 179) +* call_insn and /s: Flags. (line 49) +* call_insn and /u: Flags. (line 19) +* call_insn and /u or /i: Flags. (line 29) +* call_insn and /v: Flags. (line 44) +* CALL_INSN_FUNCTION_USAGE: Insns. (line 101) +* call_pop instruction pattern: Standard Names. (line 1002) +* CALL_POPS_ARGS: Stack Arguments. (line 133) +* CALL_REALLY_USED_REGISTERS: Register Basics. (line 46) +* CALL_USED_REGISTERS: Register Basics. (line 35) +* call_used_regs: Register Basics. (line 59) +* call_value instruction pattern: Standard Names. (line 994) +* call_value_pop instruction pattern: Standard Names. (line 1002) +* CALLER_SAVE_PROFITABLE: Caller Saves. (line 11) +* calling conventions: Stack and Calling. (line 6) +* calling functions in RTL: Calls. (line 6) +* can_create_pseudo_p: Standard Names. (line 75) +* can_fallthru: Basic Blocks. (line 57) +* canadian: Configure Terms. (line 6) +* CANNOT_CHANGE_MODE_CLASS: Register Classes. (line 522) +* CANNOT_CHANGE_MODE_CLASS and subreg semantics: Regs and Memory. + (line 280) +* canonicalization of instructions: Insn Canonicalizations. + (line 6) +* CANONICALIZE_COMPARISON: MODE_CC Condition Codes. + (line 55) +* canonicalize_funcptr_for_compare instruction pattern: Standard Names. + (line 1158) +* CASE_USE_BIT_TESTS: Misc. (line 54) +* CASE_VECTOR_MODE: Misc. (line 27) +* CASE_VECTOR_PC_RELATIVE: Misc. (line 40) +* CASE_VECTOR_SHORTEN_MODE: Misc. (line 31) +* casesi instruction pattern: Standard Names. (line 1082) +* cbranchMODE4 instruction pattern: Standard Names. (line 963) +* cc0 <1>: Regs and Memory. (line 307) +* cc0: CC0 Condition Codes. + (line 6) +* cc0, RTL sharing: Sharing. (line 27) +* cc0_rtx: Regs and Memory. (line 333) +* CC1_SPEC: Driver. (line 56) +* CC1PLUS_SPEC: Driver. (line 64) +* cc_status: CC0 Condition Codes. + (line 6) +* CC_STATUS_MDEP: CC0 Condition Codes. + (line 17) +* CC_STATUS_MDEP_INIT: CC0 Condition Codes. + (line 23) +* CCmode <1>: Machine Modes. (line 176) +* CCmode: MODE_CC Condition Codes. + (line 6) +* CDImode: Machine Modes. (line 202) +* CEIL_DIV_EXPR: Unary and Binary Expressions. + (line 6) +* CEIL_MOD_EXPR: Unary and Binary Expressions. + (line 6) +* ceilM2 instruction pattern: Standard Names. (line 583) +* CFA_FRAME_BASE_OFFSET: Frame Layout. (line 226) +* CFG, Control Flow Graph: Control Flow. (line 6) +* cfghooks.h: Maintaining the CFG. + (line 6) +* cgraph_finalize_function: Parsing pass. (line 52) +* chain_circular: GTY Options. (line 191) +* chain_next: GTY Options. (line 191) +* chain_prev: GTY Options. (line 191) +* change_address: Standard Names. (line 47) +* CHAR_TYPE_SIZE: Type Layout. (line 39) +* check_stack instruction pattern: Standard Names. (line 1245) +* CHImode: Machine Modes. (line 202) +* class definitions, register: Register Classes. (line 6) +* class preference constraints: Class Preferences. (line 6) +* class, scope: Classes. (line 6) +* CLASS_MAX_NREGS: Register Classes. (line 510) +* CLASS_TYPE_P: Types for C++. (line 65) +* classes of RTX codes: RTL Classes. (line 6) +* CLASSTYPE_DECLARED_CLASS: Classes. (line 6) +* CLASSTYPE_HAS_MUTABLE: Classes. (line 85) +* CLASSTYPE_NON_POD_P: Classes. (line 90) +* CLEANUP_DECL: Statements for C++. (line 6) +* CLEANUP_EXPR: Statements for C++. (line 6) +* CLEANUP_POINT_EXPR: Unary and Binary Expressions. + (line 6) +* CLEANUP_STMT: Statements for C++. (line 6) +* Cleanups: Cleanups. (line 6) +* CLEAR_BY_PIECES_P: Costs. (line 188) +* clear_cache instruction pattern: Standard Names. (line 1561) +* CLEAR_INSN_CACHE: Trampolines. (line 99) +* CLEAR_RATIO: Costs. (line 176) +* clobber: Side Effects. (line 100) +* clz: Arithmetic. (line 217) +* CLZ_DEFINED_VALUE_AT_ZERO: Misc. (line 319) +* clzM2 instruction pattern: Standard Names. (line 648) +* cmpmemM instruction pattern: Standard Names. (line 781) +* cmpstrM instruction pattern: Standard Names. (line 760) +* cmpstrnM instruction pattern: Standard Names. (line 747) +* code generation RTL sequences: Expander Definitions. + (line 6) +* code iterators in .md files: Code Iterators. (line 6) +* code_label: Insns. (line 119) +* code_label and /i: Flags. (line 59) +* code_label and /v: Flags. (line 44) +* CODE_LABEL_NUMBER: Insns. (line 119) +* codes, RTL expression: RTL Objects. (line 47) +* COImode: Machine Modes. (line 202) +* COLLECT2_HOST_INITIALIZATION: Host Misc. (line 32) +* COLLECT_EXPORT_LIST: Misc. (line 753) +* COLLECT_SHARED_FINI_FUNC: Macros for Initialization. + (line 44) +* COLLECT_SHARED_INIT_FUNC: Macros for Initialization. + (line 33) +* commit_edge_insertions: Maintaining the CFG. + (line 118) +* compare: Arithmetic. (line 43) +* compare, canonicalization of: Insn Canonicalizations. + (line 37) +* comparison_operator: Machine-Independent Predicates. + (line 111) +* compiler passes and files: Passes. (line 6) +* complement, bitwise: Arithmetic. (line 154) +* COMPLEX_CST: Constant expressions. + (line 6) +* COMPLEX_EXPR: Unary and Binary Expressions. + (line 6) +* COMPLEX_TYPE: Types. (line 6) +* COMPONENT_REF: Storage References. (line 6) +* Compound Expressions: Compound Expressions. + (line 6) +* Compound Lvalues: Compound Lvalues. (line 6) +* COMPOUND_EXPR: Unary and Binary Expressions. + (line 6) +* COMPOUND_LITERAL_EXPR: Unary and Binary Expressions. + (line 6) +* COMPOUND_LITERAL_EXPR_DECL: Unary and Binary Expressions. + (line 367) +* COMPOUND_LITERAL_EXPR_DECL_EXPR: Unary and Binary Expressions. + (line 367) +* computed jump: Edges. (line 128) +* computing the length of an insn: Insn Lengths. (line 6) +* concat: Regs and Memory. (line 385) +* concatn: Regs and Memory. (line 391) +* cond: Comparisons. (line 90) +* cond and attributes: Expressions. (line 37) +* cond_exec: Side Effects. (line 248) +* COND_EXPR: Unary and Binary Expressions. + (line 6) +* condition code register: Regs and Memory. (line 307) +* condition code status: Condition Code. (line 6) +* condition codes: Comparisons. (line 20) +* conditional execution <1>: Cond Exec Macros. (line 6) +* conditional execution: Conditional Execution. + (line 6) +* Conditional Expressions: Conditional Expressions. + (line 6) +* conditions, in patterns: Patterns. (line 43) +* configuration file <1>: Filesystem. (line 6) +* configuration file: Host Misc. (line 6) +* configure terms: Configure Terms. (line 6) +* CONJ_EXPR: Unary and Binary Expressions. + (line 6) +* const: Constants. (line 99) +* CONST0_RTX: Constants. (line 119) +* const0_rtx: Constants. (line 16) +* CONST1_RTX: Constants. (line 119) +* const1_rtx: Constants. (line 16) +* CONST2_RTX: Constants. (line 119) +* const2_rtx: Constants. (line 16) +* CONST_DECL: Declarations. (line 6) +* const_double: Constants. (line 32) +* const_double, RTL sharing: Sharing. (line 29) +* CONST_DOUBLE_LOW: Constants. (line 39) +* CONST_DOUBLE_OK_FOR_CONSTRAINT_P: Old Constraints. (line 69) +* CONST_DOUBLE_OK_FOR_LETTER_P: Old Constraints. (line 54) +* const_double_operand: Machine-Independent Predicates. + (line 21) +* const_fixed: Constants. (line 52) +* const_int: Constants. (line 8) +* const_int and attribute tests: Expressions. (line 47) +* const_int and attributes: Expressions. (line 10) +* const_int, RTL sharing: Sharing. (line 23) +* const_int_operand: Machine-Independent Predicates. + (line 16) +* CONST_OK_FOR_CONSTRAINT_P: Old Constraints. (line 49) +* CONST_OK_FOR_LETTER_P: Old Constraints. (line 40) +* const_string: Constants. (line 71) +* const_string and attributes: Expressions. (line 20) +* const_true_rtx: Constants. (line 26) +* const_vector: Constants. (line 59) +* const_vector, RTL sharing: Sharing. (line 32) +* constant attributes: Constant Attributes. + (line 6) +* constant definitions: Constant Definitions. + (line 6) +* CONSTANT_ADDRESS_P: Addressing Modes. (line 29) +* CONSTANT_ALIGNMENT: Storage Layout. (line 229) +* CONSTANT_P: Addressing Modes. (line 36) +* CONSTANT_POOL_ADDRESS_P: Flags. (line 10) +* CONSTANT_POOL_BEFORE_FUNCTION: Data Output. (line 76) +* constants in constraints: Simple Constraints. (line 70) +* constm1_rtx: Constants. (line 16) +* constraint modifier characters: Modifiers. (line 6) +* constraint, matching: Simple Constraints. (line 142) +* CONSTRAINT_LEN: Old Constraints. (line 12) +* constraint_num: C Constraint Interface. + (line 38) +* constraint_satisfied_p: C Constraint Interface. + (line 54) +* constraints: Constraints. (line 6) +* constraints, defining: Define Constraints. (line 6) +* constraints, defining, obsolete method: Old Constraints. (line 6) +* constraints, machine specific: Machine Constraints. + (line 6) +* constraints, testing: C Constraint Interface. + (line 6) +* CONSTRUCTOR: Unary and Binary Expressions. + (line 6) +* constructors, automatic calls: Collect2. (line 15) +* constructors, output of: Initialization. (line 6) +* container: Containers. (line 6) +* CONTINUE_STMT: Statements for C++. (line 6) +* contributors: Contributors. (line 6) +* controlling register usage: Register Basics. (line 73) +* controlling the compilation driver: Driver. (line 6) +* conventions, run-time: Interface. (line 6) +* conversions: Conversions. (line 6) +* CONVERT_EXPR: Unary and Binary Expressions. + (line 6) +* copy_rtx: Addressing Modes. (line 188) +* copy_rtx_if_shared: Sharing. (line 64) +* copysignM3 instruction pattern: Standard Names. (line 629) +* cosM2 instruction pattern: Standard Names. (line 508) +* costs of instructions: Costs. (line 6) +* CP_INTEGRAL_TYPE: Types for C++. (line 57) +* cp_namespace_decls: Namespaces. (line 49) +* CP_TYPE_CONST_NON_VOLATILE_P: Types for C++. (line 33) +* CP_TYPE_CONST_P: Types for C++. (line 24) +* CP_TYPE_QUALS: Types for C++. (line 6) +* CP_TYPE_RESTRICT_P: Types for C++. (line 30) +* CP_TYPE_VOLATILE_P: Types for C++. (line 27) +* CPLUSPLUS_CPP_SPEC: Driver. (line 51) +* CPP_SPEC: Driver. (line 44) +* CQImode: Machine Modes. (line 202) +* cross compilation and floating point: Floating Point. (line 6) +* CRT_CALL_STATIC_FUNCTION: Sections. (line 122) +* CRTSTUFF_T_CFLAGS: Target Fragment. (line 35) +* CRTSTUFF_T_CFLAGS_S: Target Fragment. (line 39) +* CSImode: Machine Modes. (line 202) +* cstoreMODE4 instruction pattern: Standard Names. (line 924) +* CTImode: Machine Modes. (line 202) +* ctrapMM4 instruction pattern: Standard Names. (line 1386) +* ctz: Arithmetic. (line 225) +* CTZ_DEFINED_VALUE_AT_ZERO: Misc. (line 320) +* ctzM2 instruction pattern: Standard Names. (line 657) +* CUMULATIVE_ARGS: Register Arguments. (line 127) +* current_function_epilogue_delay_list: Function Entry. (line 181) +* current_function_is_leaf: Leaf Functions. (line 51) +* current_function_outgoing_args_size: Stack Arguments. (line 48) +* current_function_pops_args: Function Entry. (line 106) +* current_function_pretend_args_size: Function Entry. (line 112) +* current_function_uses_only_leaf_regs: Leaf Functions. (line 51) +* current_insn_predicate: Conditional Execution. + (line 26) +* DAmode: Machine Modes. (line 152) +* data bypass: Processor pipeline description. + (line 106) +* data dependence delays: Processor pipeline description. + (line 6) +* Data Dependency Analysis: Dependency analysis. + (line 6) +* data structures: Per-Function Data. (line 6) +* DATA_ALIGNMENT: Storage Layout. (line 216) +* DATA_SECTION_ASM_OP: Sections. (line 53) +* DBR_OUTPUT_SEQEND: Instruction Output. (line 135) +* dbr_sequence_length: Instruction Output. (line 134) +* DBX_BLOCKS_FUNCTION_RELATIVE: DBX Options. (line 103) +* DBX_CONTIN_CHAR: DBX Options. (line 66) +* DBX_CONTIN_LENGTH: DBX Options. (line 56) +* DBX_DEBUGGING_INFO: DBX Options. (line 9) +* DBX_FUNCTION_FIRST: DBX Options. (line 97) +* DBX_LINES_FUNCTION_RELATIVE: DBX Options. (line 109) +* DBX_NO_XREFS: DBX Options. (line 50) +* DBX_OUTPUT_LBRAC: DBX Hooks. (line 9) +* DBX_OUTPUT_MAIN_SOURCE_FILE_END: File Names and DBX. (line 34) +* DBX_OUTPUT_MAIN_SOURCE_FILENAME: File Names and DBX. (line 9) +* DBX_OUTPUT_NFUN: DBX Hooks. (line 18) +* DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END: File Names and DBX. + (line 42) +* DBX_OUTPUT_RBRAC: DBX Hooks. (line 15) +* DBX_OUTPUT_SOURCE_LINE: DBX Hooks. (line 22) +* DBX_REGISTER_NUMBER: All Debuggers. (line 9) +* DBX_REGPARM_STABS_CODE: DBX Options. (line 87) +* DBX_REGPARM_STABS_LETTER: DBX Options. (line 92) +* DBX_STATIC_CONST_VAR_CODE: DBX Options. (line 82) +* DBX_STATIC_STAB_DATA_SECTION: DBX Options. (line 73) +* DBX_TYPE_DECL_STABS_CODE: DBX Options. (line 78) +* DBX_USE_BINCL: DBX Options. (line 115) +* DCmode: Machine Modes. (line 197) +* DDmode: Machine Modes. (line 90) +* De Morgan's law: Insn Canonicalizations. + (line 52) +* dead_or_set_p: define_peephole. (line 65) +* debug_expr: Debug Information. (line 22) +* DEBUG_EXPR_DECL: Declarations. (line 6) +* debug_insn: Insns. (line 239) +* DEBUG_SYMS_TEXT: DBX Options. (line 25) +* DEBUGGER_ARG_OFFSET: All Debuggers. (line 37) +* DEBUGGER_AUTO_OFFSET: All Debuggers. (line 28) +* decimal float library: Decimal float library routines. + (line 6) +* DECL_ALIGN: Declarations. (line 6) +* DECL_ANTICIPATED: Functions for C++. (line 42) +* DECL_ARGUMENTS: Function Basics. (line 36) +* DECL_ARRAY_DELETE_OPERATOR_P: Functions for C++. (line 158) +* DECL_ARTIFICIAL <1>: Function Basics. (line 6) +* DECL_ARTIFICIAL <2>: Function Properties. + (line 47) +* DECL_ARTIFICIAL: Working with declarations. + (line 24) +* DECL_ASSEMBLER_NAME: Function Basics. (line 19) +* DECL_ATTRIBUTES: Attributes. (line 22) +* DECL_BASE_CONSTRUCTOR_P: Functions for C++. (line 88) +* DECL_COMPLETE_CONSTRUCTOR_P: Functions for C++. (line 84) +* DECL_COMPLETE_DESTRUCTOR_P: Functions for C++. (line 98) +* DECL_CONST_MEMFUNC_P: Functions for C++. (line 71) +* DECL_CONSTRUCTOR_P: Functions for C++. (line 77) +* DECL_CONTEXT: Namespaces. (line 31) +* DECL_CONV_FN_P: Functions for C++. (line 105) +* DECL_COPY_CONSTRUCTOR_P: Functions for C++. (line 92) +* DECL_DESTRUCTOR_P: Functions for C++. (line 95) +* DECL_EXTERN_C_FUNCTION_P: Functions for C++. (line 46) +* DECL_EXTERNAL <1>: Function Properties. + (line 25) +* DECL_EXTERNAL: Declarations. (line 6) +* DECL_FUNCTION_MEMBER_P: Functions for C++. (line 61) +* DECL_FUNCTION_SPECIFIC_OPTIMIZATION <1>: Function Basics. (line 6) +* DECL_FUNCTION_SPECIFIC_OPTIMIZATION: Function Properties. + (line 61) +* DECL_FUNCTION_SPECIFIC_TARGET <1>: Function Basics. (line 6) +* DECL_FUNCTION_SPECIFIC_TARGET: Function Properties. + (line 55) +* DECL_GLOBAL_CTOR_P: Functions for C++. (line 108) +* DECL_GLOBAL_DTOR_P: Functions for C++. (line 112) +* DECL_INITIAL <1>: Function Basics. (line 51) +* DECL_INITIAL: Declarations. (line 6) +* DECL_LINKONCE_P: Functions for C++. (line 50) +* DECL_LOCAL_FUNCTION_P: Functions for C++. (line 38) +* DECL_MAIN_P: Functions for C++. (line 34) +* DECL_NAME <1>: Function Basics. (line 9) +* DECL_NAME <2>: Namespaces. (line 20) +* DECL_NAME: Working with declarations. + (line 7) +* DECL_NAMESPACE_ALIAS: Namespaces. (line 35) +* DECL_NAMESPACE_STD_P: Namespaces. (line 45) +* DECL_NON_THUNK_FUNCTION_P: Functions for C++. (line 138) +* DECL_NONCONVERTING_P: Functions for C++. (line 80) +* DECL_NONSTATIC_MEMBER_FUNCTION_P: Functions for C++. (line 68) +* DECL_OVERLOADED_OPERATOR_P: Functions for C++. (line 102) +* DECL_PURE_P: Function Properties. + (line 40) +* DECL_RESULT: Function Basics. (line 41) +* DECL_SAVED_TREE: Function Basics. (line 44) +* DECL_SIZE: Declarations. (line 6) +* DECL_STATIC_FUNCTION_P: Functions for C++. (line 65) +* DECL_STMT: Statements for C++. (line 6) +* DECL_STMT_DECL: Statements for C++. (line 6) +* DECL_THUNK_P: Functions for C++. (line 116) +* DECL_VIRTUAL_P: Function Properties. + (line 44) +* DECL_VOLATILE_MEMFUNC_P: Functions for C++. (line 74) +* declaration: Declarations. (line 6) +* declarations, RTL: RTL Declarations. (line 6) +* DECLARE_LIBRARY_RENAMES: Library Calls. (line 9) +* decrement_and_branch_until_zero instruction pattern: Standard Names. + (line 1120) +* default: GTY Options. (line 77) +* default_file_start: File Framework. (line 8) +* DEFAULT_GDB_EXTENSIONS: DBX Options. (line 18) +* DEFAULT_PCC_STRUCT_RETURN: Aggregate Return. (line 35) +* DEFAULT_SIGNED_CHAR: Type Layout. (line 153) +* define_address_constraint: Define Constraints. (line 107) +* define_asm_attributes: Tagging Insns. (line 73) +* define_attr: Defining Attributes. + (line 6) +* define_automaton: Processor pipeline description. + (line 53) +* define_bypass: Processor pipeline description. + (line 197) +* define_c_enum: Constant Definitions. + (line 49) +* define_code_attr: Code Iterators. (line 6) +* define_code_iterator: Code Iterators. (line 6) +* define_cond_exec: Conditional Execution. + (line 13) +* define_constants: Constant Definitions. + (line 6) +* define_constraint: Define Constraints. (line 48) +* define_cpu_unit: Processor pipeline description. + (line 68) +* define_delay: Delay Slots. (line 25) +* define_enum: Constant Definitions. + (line 118) +* define_enum_attr <1>: Defining Attributes. + (line 64) +* define_enum_attr: Constant Definitions. + (line 136) +* define_expand: Expander Definitions. + (line 11) +* define_insn: Patterns. (line 6) +* define_insn example: Example. (line 6) +* define_insn_and_split: Insn Splitting. (line 170) +* define_insn_reservation: Processor pipeline description. + (line 106) +* define_memory_constraint: Define Constraints. (line 88) +* define_mode_attr: Substitutions. (line 6) +* define_mode_iterator: Defining Mode Iterators. + (line 6) +* define_peephole: define_peephole. (line 6) +* define_peephole2: define_peephole2. (line 6) +* define_predicate: Defining Predicates. + (line 6) +* define_query_cpu_unit: Processor pipeline description. + (line 90) +* define_register_constraint: Define Constraints. (line 28) +* define_reservation: Processor pipeline description. + (line 186) +* define_special_predicate: Defining Predicates. + (line 6) +* define_split: Insn Splitting. (line 32) +* defining attributes and their values: Defining Attributes. + (line 6) +* defining constraints: Define Constraints. (line 6) +* defining constraints, obsolete method: Old Constraints. (line 6) +* defining jump instruction patterns: Jump Patterns. (line 6) +* defining looping instruction patterns: Looping Patterns. (line 6) +* defining peephole optimizers: Peephole Definitions. + (line 6) +* defining predicates: Defining Predicates. + (line 6) +* defining RTL sequences for code generation: Expander Definitions. + (line 6) +* delay slots, defining: Delay Slots. (line 6) +* DELAY_SLOTS_FOR_EPILOGUE: Function Entry. (line 163) +* deletable: GTY Options. (line 145) +* DELETE_IF_ORDINARY: Filesystem. (line 79) +* Dependent Patterns: Dependent Patterns. (line 6) +* desc: GTY Options. (line 77) +* destructors, output of: Initialization. (line 6) +* deterministic finite state automaton: Processor pipeline description. + (line 301) +* DF_SIZE: Type Layout. (line 129) +* DFmode: Machine Modes. (line 73) +* digits in constraint: Simple Constraints. (line 130) +* DImode: Machine Modes. (line 45) +* DIR_SEPARATOR: Filesystem. (line 18) +* DIR_SEPARATOR_2: Filesystem. (line 19) +* directory options .md: Including Patterns. (line 44) +* disabling certain registers: Register Basics. (line 73) +* dispatch table: Dispatch Tables. (line 8) +* div: Arithmetic. (line 116) +* div and attributes: Expressions. (line 64) +* division: Arithmetic. (line 136) +* divM3 instruction pattern: Standard Names. (line 222) +* divmodM4 instruction pattern: Standard Names. (line 438) +* DO_BODY: Statements for C++. (line 6) +* DO_COND: Statements for C++. (line 6) +* DO_STMT: Statements for C++. (line 6) +* DOLLARS_IN_IDENTIFIERS: Misc. (line 451) +* doloop_begin instruction pattern: Standard Names. (line 1151) +* doloop_end instruction pattern: Standard Names. (line 1130) +* DONE: Expander Definitions. + (line 74) +* DONT_USE_BUILTIN_SETJMP: Exception Region Output. + (line 79) +* DOUBLE_TYPE_SIZE: Type Layout. (line 53) +* DQmode: Machine Modes. (line 115) +* driver: Driver. (line 6) +* DRIVER_SELF_SPECS: Driver. (line 9) +* DUMPFILE_FORMAT: Filesystem. (line 67) +* DWARF2_ASM_LINE_DEBUG_INFO: SDB and DWARF. (line 50) +* DWARF2_DEBUGGING_INFO: SDB and DWARF. (line 13) +* DWARF2_FRAME_INFO: SDB and DWARF. (line 30) +* DWARF2_FRAME_REG_OUT: Frame Registers. (line 150) +* DWARF2_UNWIND_INFO: Exception Region Output. + (line 40) +* DWARF_ALT_FRAME_RETURN_COLUMN: Frame Layout. (line 152) +* DWARF_CIE_DATA_ALIGNMENT: Exception Region Output. + (line 84) +* DWARF_FRAME_REGISTERS: Frame Registers. (line 110) +* DWARF_FRAME_REGNUM: Frame Registers. (line 142) +* DWARF_REG_TO_UNWIND_COLUMN: Frame Registers. (line 134) +* DWARF_ZERO_REG: Frame Layout. (line 163) +* DYNAMIC_CHAIN_ADDRESS: Frame Layout. (line 92) +* E in constraint: Simple Constraints. (line 89) +* earlyclobber operand: Modifiers. (line 25) +* edge: Edges. (line 6) +* edge in the flow graph: Edges. (line 6) +* edge iterators: Edges. (line 15) +* edge splitting: Maintaining the CFG. + (line 118) +* EDGE_ABNORMAL: Edges. (line 128) +* EDGE_ABNORMAL, EDGE_ABNORMAL_CALL: Edges. (line 171) +* EDGE_ABNORMAL, EDGE_EH: Edges. (line 96) +* EDGE_ABNORMAL, EDGE_SIBCALL: Edges. (line 122) +* EDGE_FALLTHRU, force_nonfallthru: Edges. (line 86) +* EDOM, implicit usage: Library Calls. (line 44) +* EH_FRAME_IN_DATA_SECTION: Exception Region Output. + (line 20) +* EH_FRAME_SECTION_NAME: Exception Region Output. + (line 10) +* eh_return instruction pattern: Standard Names. (line 1326) +* EH_RETURN_DATA_REGNO: Exception Handling. (line 7) +* EH_RETURN_HANDLER_RTX: Exception Handling. (line 39) +* EH_RETURN_STACKADJ_RTX: Exception Handling. (line 22) +* EH_TABLES_CAN_BE_READ_ONLY: Exception Region Output. + (line 29) +* EH_USES: Function Entry. (line 158) +* ei_edge: Edges. (line 43) +* ei_end_p: Edges. (line 27) +* ei_last: Edges. (line 23) +* ei_next: Edges. (line 35) +* ei_one_before_end_p: Edges. (line 31) +* ei_prev: Edges. (line 39) +* ei_safe_safe: Edges. (line 47) +* ei_start: Edges. (line 19) +* ELIGIBLE_FOR_EPILOGUE_DELAY: Function Entry. (line 169) +* ELIMINABLE_REGS: Elimination. (line 47) +* ELSE_CLAUSE: Statements for C++. (line 6) +* Embedded C: Fixed-point fractional library routines. + (line 6) +* EMIT_MODE_SET: Mode Switching. (line 74) +* Empty Statements: Empty Statements. (line 6) +* EMPTY_CLASS_EXPR: Statements for C++. (line 6) +* EMPTY_FIELD_BOUNDARY: Storage Layout. (line 292) +* Emulated TLS: Emulated TLS. (line 6) +* ENABLE_EXECUTE_STACK: Trampolines. (line 109) +* enabled: Disable Insn Alternatives. + (line 6) +* ENDFILE_SPEC: Driver. (line 156) +* endianness: Portability. (line 21) +* ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR: Basic Blocks. (line 28) +* enum machine_mode: Machine Modes. (line 6) +* enum reg_class: Register Classes. (line 67) +* ENUMERAL_TYPE: Types. (line 6) +* enumerations: Constant Definitions. + (line 49) +* epilogue: Function Entry. (line 6) +* epilogue instruction pattern: Standard Names. (line 1358) +* EPILOGUE_USES: Function Entry. (line 152) +* eq: Comparisons. (line 52) +* eq and attributes: Expressions. (line 64) +* eq_attr: Expressions. (line 85) +* EQ_EXPR: Unary and Binary Expressions. + (line 6) +* equal: Comparisons. (line 52) +* errno, implicit usage: Library Calls. (line 56) +* EXACT_DIV_EXPR: Unary and Binary Expressions. + (line 6) +* examining SSA_NAMEs: SSA. (line 218) +* exception handling <1>: Edges. (line 96) +* exception handling: Exception Handling. (line 6) +* exception_receiver instruction pattern: Standard Names. (line 1290) +* exclamation point: Multi-Alternative. (line 47) +* exclusion_set: Processor pipeline description. + (line 220) +* exclusive-or, bitwise: Arithmetic. (line 168) +* EXIT_EXPR: Unary and Binary Expressions. + (line 6) +* EXIT_IGNORE_STACK: Function Entry. (line 140) +* expander definitions: Expander Definitions. + (line 6) +* expM2 instruction pattern: Standard Names. (line 524) +* EXPR_FILENAME: Working with declarations. + (line 14) +* EXPR_LINENO: Working with declarations. + (line 20) +* expr_list: Insns. (line 545) +* EXPR_STMT: Statements for C++. (line 6) +* EXPR_STMT_EXPR: Statements for C++. (line 6) +* expression: Expression trees. (line 6) +* expression codes: RTL Objects. (line 47) +* extendMN2 instruction pattern: Standard Names. (line 839) +* extensible constraints: Simple Constraints. (line 173) +* EXTRA_ADDRESS_CONSTRAINT: Old Constraints. (line 123) +* EXTRA_CONSTRAINT: Old Constraints. (line 74) +* EXTRA_CONSTRAINT_STR: Old Constraints. (line 95) +* EXTRA_MEMORY_CONSTRAINT: Old Constraints. (line 100) +* EXTRA_SPECS: Driver. (line 183) +* extv instruction pattern: Standard Names. (line 875) +* extzv instruction pattern: Standard Names. (line 890) +* F in constraint: Simple Constraints. (line 94) +* FAIL: Expander Definitions. + (line 80) +* fall-thru: Edges. (line 69) +* FATAL_EXIT_CODE: Host Misc. (line 6) +* FDL, GNU Free Documentation License: GNU Free Documentation License. + (line 6) +* features, optional, in system conventions: Run-time Target. + (line 59) +* ffs: Arithmetic. (line 211) +* ffsM2 instruction pattern: Standard Names. (line 638) +* FIELD_DECL: Declarations. (line 6) +* file_end_indicate_exec_stack: File Framework. (line 41) +* files and passes of the compiler: Passes. (line 6) +* files, generated: Files. (line 6) +* final_absence_set: Processor pipeline description. + (line 220) +* FINAL_PRESCAN_INSN: Instruction Output. (line 61) +* final_presence_set: Processor pipeline description. + (line 220) +* final_scan_insn: Function Entry. (line 181) +* final_sequence: Instruction Output. (line 145) +* FIND_BASE_TERM: Addressing Modes. (line 119) +* FINI_ARRAY_SECTION_ASM_OP: Sections. (line 115) +* FINI_SECTION_ASM_OP: Sections. (line 100) +* finite state automaton minimization: Processor pipeline description. + (line 301) +* FIRST_PARM_OFFSET: Frame Layout. (line 67) +* FIRST_PARM_OFFSET and virtual registers: Regs and Memory. (line 65) +* FIRST_PSEUDO_REGISTER: Register Basics. (line 9) +* FIRST_STACK_REG: Stack Registers. (line 27) +* FIRST_VIRTUAL_REGISTER: Regs and Memory. (line 51) +* fix: Conversions. (line 66) +* FIX_TRUNC_EXPR: Unary and Binary Expressions. + (line 6) +* fix_truncMN2 instruction pattern: Standard Names. (line 826) +* fixed register: Register Basics. (line 15) +* fixed-point fractional library: Fixed-point fractional library routines. + (line 6) +* FIXED_CONVERT_EXPR: Unary and Binary Expressions. + (line 6) +* FIXED_CST: Constant expressions. + (line 6) +* FIXED_POINT_TYPE: Types. (line 6) +* FIXED_REGISTERS: Register Basics. (line 15) +* fixed_regs: Register Basics. (line 59) +* fixMN2 instruction pattern: Standard Names. (line 806) +* FIXUNS_TRUNC_LIKE_FIX_TRUNC: Misc. (line 100) +* fixuns_truncMN2 instruction pattern: Standard Names. (line 830) +* fixunsMN2 instruction pattern: Standard Names. (line 815) +* flags in RTL expression: Flags. (line 6) +* float: Conversions. (line 58) +* FLOAT_EXPR: Unary and Binary Expressions. + (line 6) +* float_extend: Conversions. (line 33) +* FLOAT_LIB_COMPARE_RETURNS_BOOL: Library Calls. (line 25) +* FLOAT_STORE_FLAG_VALUE: Misc. (line 301) +* float_truncate: Conversions. (line 53) +* FLOAT_TYPE_SIZE: Type Layout. (line 49) +* FLOAT_WORDS_BIG_ENDIAN: Storage Layout. (line 36) +* FLOAT_WORDS_BIG_ENDIAN, (lack of) effect on subreg: Regs and Memory. + (line 226) +* floating point and cross compilation: Floating Point. (line 6) +* Floating Point Emulation: Target Fragment. (line 15) +* floatMN2 instruction pattern: Standard Names. (line 798) +* floatunsMN2 instruction pattern: Standard Names. (line 802) +* FLOOR_DIV_EXPR: Unary and Binary Expressions. + (line 6) +* FLOOR_MOD_EXPR: Unary and Binary Expressions. + (line 6) +* floorM2 instruction pattern: Standard Names. (line 559) +* flow-insensitive alias analysis: Alias analysis. (line 6) +* flow-sensitive alias analysis: Alias analysis. (line 6) +* fma: Arithmetic. (line 111) +* fmaM4 instruction pattern: Standard Names. (line 234) +* fmodM3 instruction pattern: Standard Names. (line 490) +* fmsM4 instruction pattern: Standard Names. (line 243) +* fnmaM4 instruction pattern: Standard Names. (line 249) +* fnmsM4 instruction pattern: Standard Names. (line 255) +* FOR_BODY: Statements for C++. (line 6) +* FOR_COND: Statements for C++. (line 6) +* FOR_EXPR: Statements for C++. (line 6) +* FOR_INIT_STMT: Statements for C++. (line 6) +* FOR_STMT: Statements for C++. (line 6) +* FORCE_CODE_SECTION_ALIGN: Sections. (line 146) +* force_reg: Standard Names. (line 36) +* fract_convert: Conversions. (line 82) +* FRACT_TYPE_SIZE: Type Layout. (line 68) +* fractional types: Fixed-point fractional library routines. + (line 6) +* fractMN2 instruction pattern: Standard Names. (line 848) +* fractunsMN2 instruction pattern: Standard Names. (line 863) +* frame layout: Frame Layout. (line 6) +* FRAME_ADDR_RTX: Frame Layout. (line 116) +* FRAME_GROWS_DOWNWARD: Frame Layout. (line 31) +* FRAME_GROWS_DOWNWARD and virtual registers: Regs and Memory. + (line 69) +* FRAME_POINTER_CFA_OFFSET: Frame Layout. (line 212) +* frame_pointer_needed: Function Entry. (line 34) +* FRAME_POINTER_REGNUM: Frame Registers. (line 14) +* FRAME_POINTER_REGNUM and virtual registers: Regs and Memory. + (line 74) +* frame_pointer_rtx: Frame Registers. (line 104) +* frame_related: Flags. (line 247) +* frame_related, in insn, call_insn, jump_insn, barrier, and set: Flags. + (line 125) +* frame_related, in mem: Flags. (line 103) +* frame_related, in reg: Flags. (line 112) +* frame_related, in symbol_ref: Flags. (line 183) +* frequency, count, BB_FREQ_BASE: Profile information. + (line 30) +* ftruncM2 instruction pattern: Standard Names. (line 821) +* function <1>: Functions for C++. (line 6) +* function: Functions. (line 6) +* function call conventions: Interface. (line 6) +* function entry and exit: Function Entry. (line 6) +* function entry point, alternate function entry point: Edges. + (line 180) +* function properties: Function Properties. + (line 6) +* function-call insns: Calls. (line 6) +* FUNCTION_ARG: Register Arguments. (line 11) +* FUNCTION_ARG_ADVANCE: Register Arguments. (line 185) +* FUNCTION_ARG_OFFSET: Register Arguments. (line 196) +* FUNCTION_ARG_PADDING: Register Arguments. (line 203) +* FUNCTION_ARG_REGNO_P: Register Arguments. (line 244) +* FUNCTION_BOUNDARY: Storage Layout. (line 158) +* FUNCTION_DECL <1>: Functions. (line 6) +* FUNCTION_DECL: Functions for C++. (line 6) +* FUNCTION_INCOMING_ARG: Register Arguments. (line 68) +* FUNCTION_MODE: Misc. (line 356) +* FUNCTION_PROFILER: Profiling. (line 9) +* FUNCTION_TYPE: Types. (line 6) +* FUNCTION_VALUE: Scalar Return. (line 52) +* FUNCTION_VALUE_REGNO_P: Scalar Return. (line 78) +* functions, leaf: Leaf Functions. (line 6) +* fundamental type: Types. (line 6) +* G in constraint: Simple Constraints. (line 98) +* g in constraint: Simple Constraints. (line 120) +* garbage collector, invocation: Invoking the garbage collector. + (line 6) +* garbage collector, troubleshooting: Troubleshooting. (line 6) +* GCC and portability: Portability. (line 6) +* GCC_DRIVER_HOST_INITIALIZATION: Host Misc. (line 36) +* gcov_type: Profile information. + (line 41) +* ge: Comparisons. (line 72) +* ge and attributes: Expressions. (line 64) +* GE_EXPR: Unary and Binary Expressions. + (line 6) +* GEN_ERRNO_RTX: Library Calls. (line 57) +* gencodes: RTL passes. (line 18) +* general_operand: Machine-Independent Predicates. + (line 105) +* GENERAL_REGS: Register Classes. (line 23) +* generated files: Files. (line 6) +* generating assembler output: Output Statement. (line 6) +* generating insns: RTL Template. (line 6) +* GENERIC <1>: GENERIC. (line 6) +* GENERIC: Parsing pass. (line 6) +* generic predicates: Machine-Independent Predicates. + (line 6) +* genflags: RTL passes. (line 18) +* get_attr: Expressions. (line 80) +* get_attr_length: Insn Lengths. (line 46) +* GET_CLASS_NARROWEST_MODE: Machine Modes. (line 333) +* GET_CODE: RTL Objects. (line 47) +* get_frame_size: Elimination. (line 34) +* get_insns: Insns. (line 34) +* get_last_insn: Insns. (line 34) +* GET_MODE: Machine Modes. (line 280) +* GET_MODE_ALIGNMENT: Machine Modes. (line 320) +* GET_MODE_BITSIZE: Machine Modes. (line 304) +* GET_MODE_CLASS: Machine Modes. (line 294) +* GET_MODE_FBIT: Machine Modes. (line 311) +* GET_MODE_IBIT: Machine Modes. (line 307) +* GET_MODE_MASK: Machine Modes. (line 315) +* GET_MODE_NAME: Machine Modes. (line 291) +* GET_MODE_NUNITS: Machine Modes. (line 329) +* GET_MODE_SIZE: Machine Modes. (line 301) +* GET_MODE_UNIT_SIZE: Machine Modes. (line 323) +* GET_MODE_WIDER_MODE: Machine Modes. (line 297) +* GET_RTX_CLASS: RTL Classes. (line 6) +* GET_RTX_FORMAT: RTL Classes. (line 131) +* GET_RTX_LENGTH: RTL Classes. (line 128) +* geu: Comparisons. (line 72) +* geu and attributes: Expressions. (line 64) +* GGC: Type Information. (line 6) +* ggc_collect: Invoking the garbage collector. + (line 6) +* GIMPLE <1>: Gimplification pass. + (line 6) +* GIMPLE <2>: GIMPLE. (line 6) +* GIMPLE: Parsing pass. (line 14) +* GIMPLE Exception Handling: GIMPLE Exception Handling. + (line 6) +* GIMPLE instruction set: GIMPLE instruction set. + (line 6) +* GIMPLE sequences: GIMPLE sequences. (line 6) +* gimple_addresses_taken: Manipulating GIMPLE statements. + (line 90) +* GIMPLE_ASM: GIMPLE_ASM. (line 6) +* gimple_asm_clear_volatile: GIMPLE_ASM. (line 63) +* gimple_asm_clobber_op: GIMPLE_ASM. (line 46) +* gimple_asm_input_op: GIMPLE_ASM. (line 30) +* gimple_asm_nclobbers: GIMPLE_ASM. (line 27) +* gimple_asm_ninputs: GIMPLE_ASM. (line 21) +* gimple_asm_noutputs: GIMPLE_ASM. (line 24) +* gimple_asm_output_op: GIMPLE_ASM. (line 38) +* gimple_asm_set_clobber_op: GIMPLE_ASM. (line 50) +* gimple_asm_set_input_op: GIMPLE_ASM. (line 34) +* gimple_asm_set_output_op: GIMPLE_ASM. (line 42) +* gimple_asm_set_volatile: GIMPLE_ASM. (line 60) +* gimple_asm_string: GIMPLE_ASM. (line 53) +* gimple_asm_volatile_p: GIMPLE_ASM. (line 57) +* GIMPLE_ASSIGN: GIMPLE_ASSIGN. (line 6) +* gimple_assign_cast_p <1>: Logical Operators. (line 160) +* gimple_assign_cast_p: GIMPLE_ASSIGN. (line 93) +* gimple_assign_lhs: GIMPLE_ASSIGN. (line 51) +* gimple_assign_lhs_ptr: GIMPLE_ASSIGN. (line 54) +* gimple_assign_rhs1: GIMPLE_ASSIGN. (line 57) +* gimple_assign_rhs1_ptr: GIMPLE_ASSIGN. (line 60) +* gimple_assign_rhs2: GIMPLE_ASSIGN. (line 64) +* gimple_assign_rhs2_ptr: GIMPLE_ASSIGN. (line 67) +* gimple_assign_rhs3: GIMPLE_ASSIGN. (line 71) +* gimple_assign_rhs3_ptr: GIMPLE_ASSIGN. (line 74) +* gimple_assign_rhs_class: GIMPLE_ASSIGN. (line 46) +* gimple_assign_rhs_code: GIMPLE_ASSIGN. (line 41) +* gimple_assign_set_lhs: GIMPLE_ASSIGN. (line 78) +* gimple_assign_set_rhs1: GIMPLE_ASSIGN. (line 81) +* gimple_assign_set_rhs2: GIMPLE_ASSIGN. (line 85) +* gimple_assign_set_rhs3: GIMPLE_ASSIGN. (line 89) +* gimple_bb: Manipulating GIMPLE statements. + (line 18) +* GIMPLE_BIND: GIMPLE_BIND. (line 6) +* gimple_bind_add_seq: GIMPLE_BIND. (line 36) +* gimple_bind_add_stmt: GIMPLE_BIND. (line 32) +* gimple_bind_append_vars: GIMPLE_BIND. (line 19) +* gimple_bind_block: GIMPLE_BIND. (line 40) +* gimple_bind_body: GIMPLE_BIND. (line 23) +* gimple_bind_set_block: GIMPLE_BIND. (line 45) +* gimple_bind_set_body: GIMPLE_BIND. (line 28) +* gimple_bind_set_vars: GIMPLE_BIND. (line 15) +* gimple_bind_vars: GIMPLE_BIND. (line 12) +* gimple_block: Manipulating GIMPLE statements. + (line 21) +* gimple_build_asm: GIMPLE_ASM. (line 8) +* gimple_build_asm_vec: GIMPLE_ASM. (line 17) +* gimple_build_assign: GIMPLE_ASSIGN. (line 7) +* gimple_build_assign_with_ops: GIMPLE_ASSIGN. (line 30) +* gimple_build_bind: GIMPLE_BIND. (line 8) +* gimple_build_call: GIMPLE_CALL. (line 8) +* gimple_build_call_from_tree: GIMPLE_CALL. (line 16) +* gimple_build_call_vec: GIMPLE_CALL. (line 25) +* gimple_build_catch: GIMPLE_CATCH. (line 8) +* gimple_build_cond: GIMPLE_COND. (line 8) +* gimple_build_cond_from_tree: GIMPLE_COND. (line 16) +* gimple_build_debug_bind: GIMPLE_DEBUG. (line 8) +* gimple_build_eh_filter: GIMPLE_EH_FILTER. (line 8) +* gimple_build_goto: GIMPLE_LABEL. (line 18) +* gimple_build_label: GIMPLE_LABEL. (line 7) +* gimple_build_nop: GIMPLE_NOP. (line 7) +* gimple_build_omp_atomic_load: GIMPLE_OMP_ATOMIC_LOAD. + (line 8) +* gimple_build_omp_atomic_store: GIMPLE_OMP_ATOMIC_STORE. + (line 7) +* gimple_build_omp_continue: GIMPLE_OMP_CONTINUE. + (line 8) +* gimple_build_omp_critical: GIMPLE_OMP_CRITICAL. + (line 8) +* gimple_build_omp_for: GIMPLE_OMP_FOR. (line 9) +* gimple_build_omp_master: GIMPLE_OMP_MASTER. (line 7) +* gimple_build_omp_ordered: GIMPLE_OMP_ORDERED. (line 7) +* gimple_build_omp_parallel: GIMPLE_OMP_PARALLEL. + (line 8) +* gimple_build_omp_return: GIMPLE_OMP_RETURN. (line 7) +* gimple_build_omp_section: GIMPLE_OMP_SECTION. (line 7) +* gimple_build_omp_sections: GIMPLE_OMP_SECTIONS. + (line 8) +* gimple_build_omp_sections_switch: GIMPLE_OMP_SECTIONS. + (line 14) +* gimple_build_omp_single: GIMPLE_OMP_SINGLE. (line 8) +* gimple_build_resx: GIMPLE_RESX. (line 7) +* gimple_build_return: GIMPLE_RETURN. (line 7) +* gimple_build_switch: GIMPLE_SWITCH. (line 8) +* gimple_build_switch_vec: GIMPLE_SWITCH. (line 16) +* gimple_build_try: GIMPLE_TRY. (line 8) +* gimple_build_wce: GIMPLE_WITH_CLEANUP_EXPR. + (line 7) +* GIMPLE_CALL: GIMPLE_CALL. (line 6) +* gimple_call_arg: GIMPLE_CALL. (line 66) +* gimple_call_arg_ptr: GIMPLE_CALL. (line 71) +* gimple_call_cannot_inline_p: GIMPLE_CALL. (line 91) +* gimple_call_chain: GIMPLE_CALL. (line 57) +* gimple_call_copy_skip_args: GIMPLE_CALL. (line 98) +* gimple_call_fn: GIMPLE_CALL. (line 38) +* gimple_call_fndecl: GIMPLE_CALL. (line 46) +* gimple_call_lhs: GIMPLE_CALL. (line 29) +* gimple_call_lhs_ptr: GIMPLE_CALL. (line 32) +* gimple_call_mark_uninlinable: GIMPLE_CALL. (line 88) +* gimple_call_noreturn_p: GIMPLE_CALL. (line 94) +* gimple_call_num_args: GIMPLE_CALL. (line 63) +* gimple_call_return_type: GIMPLE_CALL. (line 54) +* gimple_call_set_arg: GIMPLE_CALL. (line 76) +* gimple_call_set_chain: GIMPLE_CALL. (line 60) +* gimple_call_set_fn: GIMPLE_CALL. (line 42) +* gimple_call_set_fndecl: GIMPLE_CALL. (line 51) +* gimple_call_set_lhs: GIMPLE_CALL. (line 35) +* gimple_call_set_tail: GIMPLE_CALL. (line 80) +* gimple_call_tail_p: GIMPLE_CALL. (line 85) +* GIMPLE_CATCH: GIMPLE_CATCH. (line 6) +* gimple_catch_handler: GIMPLE_CATCH. (line 20) +* gimple_catch_set_handler: GIMPLE_CATCH. (line 28) +* gimple_catch_set_types: GIMPLE_CATCH. (line 24) +* gimple_catch_types: GIMPLE_CATCH. (line 13) +* gimple_catch_types_ptr: GIMPLE_CATCH. (line 16) +* gimple_code: Manipulating GIMPLE statements. + (line 15) +* GIMPLE_COND: GIMPLE_COND. (line 6) +* gimple_cond_code: GIMPLE_COND. (line 21) +* gimple_cond_false_label: GIMPLE_COND. (line 60) +* gimple_cond_lhs: GIMPLE_COND. (line 30) +* gimple_cond_make_false: GIMPLE_COND. (line 64) +* gimple_cond_make_true: GIMPLE_COND. (line 67) +* gimple_cond_rhs: GIMPLE_COND. (line 38) +* gimple_cond_set_code: GIMPLE_COND. (line 26) +* gimple_cond_set_false_label: GIMPLE_COND. (line 56) +* gimple_cond_set_lhs: GIMPLE_COND. (line 34) +* gimple_cond_set_rhs: GIMPLE_COND. (line 42) +* gimple_cond_set_true_label: GIMPLE_COND. (line 51) +* gimple_cond_true_label: GIMPLE_COND. (line 46) +* gimple_copy: Manipulating GIMPLE statements. + (line 147) +* GIMPLE_DEBUG: GIMPLE_DEBUG. (line 6) +* GIMPLE_DEBUG_BIND: GIMPLE_DEBUG. (line 6) +* gimple_debug_bind_get_value: GIMPLE_DEBUG. (line 48) +* gimple_debug_bind_get_value_ptr: GIMPLE_DEBUG. (line 53) +* gimple_debug_bind_get_var: GIMPLE_DEBUG. (line 45) +* gimple_debug_bind_has_value_p: GIMPLE_DEBUG. (line 70) +* gimple_debug_bind_p: Logical Operators. (line 164) +* gimple_debug_bind_reset_value: GIMPLE_DEBUG. (line 66) +* gimple_debug_bind_set_value: GIMPLE_DEBUG. (line 62) +* gimple_debug_bind_set_var: GIMPLE_DEBUG. (line 58) +* gimple_def_ops: Manipulating GIMPLE statements. + (line 94) +* GIMPLE_EH_FILTER: GIMPLE_EH_FILTER. (line 6) +* gimple_eh_filter_failure: GIMPLE_EH_FILTER. (line 19) +* gimple_eh_filter_must_not_throw: GIMPLE_EH_FILTER. (line 33) +* gimple_eh_filter_set_failure: GIMPLE_EH_FILTER. (line 29) +* gimple_eh_filter_set_must_not_throw: GIMPLE_EH_FILTER. (line 37) +* gimple_eh_filter_set_types: GIMPLE_EH_FILTER. (line 24) +* gimple_eh_filter_types: GIMPLE_EH_FILTER. (line 12) +* gimple_eh_filter_types_ptr: GIMPLE_EH_FILTER. (line 15) +* gimple_expr_code: Manipulating GIMPLE statements. + (line 31) +* gimple_expr_type: Manipulating GIMPLE statements. + (line 24) +* gimple_goto_dest: GIMPLE_LABEL. (line 21) +* gimple_goto_set_dest: GIMPLE_LABEL. (line 24) +* gimple_has_mem_ops: Manipulating GIMPLE statements. + (line 72) +* gimple_has_ops: Manipulating GIMPLE statements. + (line 69) +* gimple_has_volatile_ops: Manipulating GIMPLE statements. + (line 134) +* GIMPLE_LABEL: GIMPLE_LABEL. (line 6) +* gimple_label_label: GIMPLE_LABEL. (line 11) +* gimple_label_set_label: GIMPLE_LABEL. (line 14) +* gimple_loaded_syms: Manipulating GIMPLE statements. + (line 122) +* gimple_locus: Manipulating GIMPLE statements. + (line 42) +* gimple_locus_empty_p: Manipulating GIMPLE statements. + (line 48) +* gimple_modified_p: Manipulating GIMPLE statements. + (line 130) +* gimple_no_warning_p: Manipulating GIMPLE statements. + (line 51) +* GIMPLE_NOP: GIMPLE_NOP. (line 6) +* gimple_nop_p: GIMPLE_NOP. (line 10) +* gimple_num_ops <1>: Logical Operators. (line 78) +* gimple_num_ops: Manipulating GIMPLE statements. + (line 75) +* GIMPLE_OMP_ATOMIC_LOAD: GIMPLE_OMP_ATOMIC_LOAD. + (line 6) +* gimple_omp_atomic_load_lhs: GIMPLE_OMP_ATOMIC_LOAD. + (line 17) +* gimple_omp_atomic_load_rhs: GIMPLE_OMP_ATOMIC_LOAD. + (line 24) +* gimple_omp_atomic_load_set_lhs: GIMPLE_OMP_ATOMIC_LOAD. + (line 14) +* gimple_omp_atomic_load_set_rhs: GIMPLE_OMP_ATOMIC_LOAD. + (line 21) +* GIMPLE_OMP_ATOMIC_STORE: GIMPLE_OMP_ATOMIC_STORE. + (line 6) +* gimple_omp_atomic_store_set_val: GIMPLE_OMP_ATOMIC_STORE. + (line 12) +* gimple_omp_atomic_store_val: GIMPLE_OMP_ATOMIC_STORE. + (line 15) +* gimple_omp_body: GIMPLE_OMP_PARALLEL. + (line 24) +* GIMPLE_OMP_CONTINUE: GIMPLE_OMP_CONTINUE. + (line 6) +* gimple_omp_continue_control_def: GIMPLE_OMP_CONTINUE. + (line 13) +* gimple_omp_continue_control_def_ptr: GIMPLE_OMP_CONTINUE. + (line 17) +* gimple_omp_continue_control_use: GIMPLE_OMP_CONTINUE. + (line 24) +* gimple_omp_continue_control_use_ptr: GIMPLE_OMP_CONTINUE. + (line 28) +* gimple_omp_continue_set_control_def: GIMPLE_OMP_CONTINUE. + (line 20) +* gimple_omp_continue_set_control_use: GIMPLE_OMP_CONTINUE. + (line 31) +* GIMPLE_OMP_CRITICAL: GIMPLE_OMP_CRITICAL. + (line 6) +* gimple_omp_critical_name: GIMPLE_OMP_CRITICAL. + (line 13) +* gimple_omp_critical_name_ptr: GIMPLE_OMP_CRITICAL. + (line 16) +* gimple_omp_critical_set_name: GIMPLE_OMP_CRITICAL. + (line 21) +* GIMPLE_OMP_FOR: GIMPLE_OMP_FOR. (line 6) +* gimple_omp_for_clauses: GIMPLE_OMP_FOR. (line 20) +* gimple_omp_for_clauses_ptr: GIMPLE_OMP_FOR. (line 23) +* gimple_omp_for_cond: GIMPLE_OMP_FOR. (line 83) +* gimple_omp_for_final: GIMPLE_OMP_FOR. (line 51) +* gimple_omp_for_final_ptr: GIMPLE_OMP_FOR. (line 54) +* gimple_omp_for_incr: GIMPLE_OMP_FOR. (line 61) +* gimple_omp_for_incr_ptr: GIMPLE_OMP_FOR. (line 64) +* gimple_omp_for_index: GIMPLE_OMP_FOR. (line 31) +* gimple_omp_for_index_ptr: GIMPLE_OMP_FOR. (line 34) +* gimple_omp_for_initial: GIMPLE_OMP_FOR. (line 41) +* gimple_omp_for_initial_ptr: GIMPLE_OMP_FOR. (line 44) +* gimple_omp_for_pre_body: GIMPLE_OMP_FOR. (line 70) +* gimple_omp_for_set_clauses: GIMPLE_OMP_FOR. (line 27) +* gimple_omp_for_set_cond: GIMPLE_OMP_FOR. (line 80) +* gimple_omp_for_set_final: GIMPLE_OMP_FOR. (line 58) +* gimple_omp_for_set_incr: GIMPLE_OMP_FOR. (line 67) +* gimple_omp_for_set_index: GIMPLE_OMP_FOR. (line 38) +* gimple_omp_for_set_initial: GIMPLE_OMP_FOR. (line 48) +* gimple_omp_for_set_pre_body: GIMPLE_OMP_FOR. (line 75) +* GIMPLE_OMP_MASTER: GIMPLE_OMP_MASTER. (line 6) +* GIMPLE_OMP_ORDERED: GIMPLE_OMP_ORDERED. (line 6) +* GIMPLE_OMP_PARALLEL: GIMPLE_OMP_PARALLEL. + (line 6) +* gimple_omp_parallel_child_fn: GIMPLE_OMP_PARALLEL. + (line 42) +* gimple_omp_parallel_child_fn_ptr: GIMPLE_OMP_PARALLEL. + (line 46) +* gimple_omp_parallel_clauses: GIMPLE_OMP_PARALLEL. + (line 31) +* gimple_omp_parallel_clauses_ptr: GIMPLE_OMP_PARALLEL. + (line 34) +* gimple_omp_parallel_combined_p: GIMPLE_OMP_PARALLEL. + (line 16) +* gimple_omp_parallel_data_arg: GIMPLE_OMP_PARALLEL. + (line 54) +* gimple_omp_parallel_data_arg_ptr: GIMPLE_OMP_PARALLEL. + (line 58) +* gimple_omp_parallel_set_child_fn: GIMPLE_OMP_PARALLEL. + (line 51) +* gimple_omp_parallel_set_clauses: GIMPLE_OMP_PARALLEL. + (line 38) +* gimple_omp_parallel_set_combined_p: GIMPLE_OMP_PARALLEL. + (line 20) +* gimple_omp_parallel_set_data_arg: GIMPLE_OMP_PARALLEL. + (line 62) +* GIMPLE_OMP_RETURN: GIMPLE_OMP_RETURN. (line 6) +* gimple_omp_return_nowait_p: GIMPLE_OMP_RETURN. (line 14) +* gimple_omp_return_set_nowait: GIMPLE_OMP_RETURN. (line 11) +* GIMPLE_OMP_SECTION: GIMPLE_OMP_SECTION. (line 6) +* gimple_omp_section_last_p: GIMPLE_OMP_SECTION. (line 12) +* gimple_omp_section_set_last: GIMPLE_OMP_SECTION. (line 16) +* GIMPLE_OMP_SECTIONS: GIMPLE_OMP_SECTIONS. + (line 6) +* gimple_omp_sections_clauses: GIMPLE_OMP_SECTIONS. + (line 30) +* gimple_omp_sections_clauses_ptr: GIMPLE_OMP_SECTIONS. + (line 33) +* gimple_omp_sections_control: GIMPLE_OMP_SECTIONS. + (line 17) +* gimple_omp_sections_control_ptr: GIMPLE_OMP_SECTIONS. + (line 21) +* gimple_omp_sections_set_clauses: GIMPLE_OMP_SECTIONS. + (line 37) +* gimple_omp_sections_set_control: GIMPLE_OMP_SECTIONS. + (line 26) +* gimple_omp_set_body: GIMPLE_OMP_PARALLEL. + (line 28) +* GIMPLE_OMP_SINGLE: GIMPLE_OMP_SINGLE. (line 6) +* gimple_omp_single_clauses: GIMPLE_OMP_SINGLE. (line 14) +* gimple_omp_single_clauses_ptr: GIMPLE_OMP_SINGLE. (line 17) +* gimple_omp_single_set_clauses: GIMPLE_OMP_SINGLE. (line 21) +* gimple_op <1>: Manipulating GIMPLE statements. + (line 81) +* gimple_op: Logical Operators. (line 81) +* gimple_op_ptr: Manipulating GIMPLE statements. + (line 84) +* gimple_ops <1>: Logical Operators. (line 84) +* gimple_ops: Manipulating GIMPLE statements. + (line 78) +* GIMPLE_PHI: GIMPLE_PHI. (line 6) +* gimple_phi_arg: GIMPLE_PHI. (line 28) +* gimple_phi_capacity: GIMPLE_PHI. (line 10) +* gimple_phi_num_args: GIMPLE_PHI. (line 14) +* gimple_phi_result: GIMPLE_PHI. (line 19) +* gimple_phi_result_ptr: GIMPLE_PHI. (line 22) +* gimple_phi_set_arg: GIMPLE_PHI. (line 33) +* gimple_phi_set_result: GIMPLE_PHI. (line 25) +* gimple_plf: Manipulating GIMPLE statements. + (line 66) +* GIMPLE_RESX: GIMPLE_RESX. (line 6) +* gimple_resx_region: GIMPLE_RESX. (line 13) +* gimple_resx_set_region: GIMPLE_RESX. (line 16) +* GIMPLE_RETURN: GIMPLE_RETURN. (line 6) +* gimple_return_retval: GIMPLE_RETURN. (line 10) +* gimple_return_set_retval: GIMPLE_RETURN. (line 14) +* gimple_seq_add_seq: GIMPLE sequences. (line 32) +* gimple_seq_add_stmt: GIMPLE sequences. (line 26) +* gimple_seq_alloc: GIMPLE sequences. (line 62) +* gimple_seq_copy: GIMPLE sequences. (line 67) +* gimple_seq_deep_copy: GIMPLE sequences. (line 37) +* gimple_seq_empty_p: GIMPLE sequences. (line 70) +* gimple_seq_first: GIMPLE sequences. (line 44) +* gimple_seq_init: GIMPLE sequences. (line 59) +* gimple_seq_last: GIMPLE sequences. (line 47) +* gimple_seq_reverse: GIMPLE sequences. (line 40) +* gimple_seq_set_first: GIMPLE sequences. (line 55) +* gimple_seq_set_last: GIMPLE sequences. (line 51) +* gimple_seq_singleton_p: GIMPLE sequences. (line 79) +* gimple_set_block: Manipulating GIMPLE statements. + (line 39) +* gimple_set_def_ops: Manipulating GIMPLE statements. + (line 98) +* gimple_set_has_volatile_ops: Manipulating GIMPLE statements. + (line 138) +* gimple_set_locus: Manipulating GIMPLE statements. + (line 45) +* gimple_set_op: Manipulating GIMPLE statements. + (line 87) +* gimple_set_plf: Manipulating GIMPLE statements. + (line 62) +* gimple_set_use_ops: Manipulating GIMPLE statements. + (line 105) +* gimple_set_vdef_ops: Manipulating GIMPLE statements. + (line 119) +* gimple_set_visited: Manipulating GIMPLE statements. + (line 55) +* gimple_set_vuse_ops: Manipulating GIMPLE statements. + (line 112) +* gimple_statement_base: Tuple representation. + (line 14) +* gimple_statement_with_ops: Tuple representation. + (line 96) +* gimple_stored_syms: Manipulating GIMPLE statements. + (line 126) +* GIMPLE_SWITCH: GIMPLE_SWITCH. (line 6) +* gimple_switch_default_label: GIMPLE_SWITCH. (line 46) +* gimple_switch_index: GIMPLE_SWITCH. (line 31) +* gimple_switch_label: GIMPLE_SWITCH. (line 37) +* gimple_switch_num_labels: GIMPLE_SWITCH. (line 22) +* gimple_switch_set_default_label: GIMPLE_SWITCH. (line 50) +* gimple_switch_set_index: GIMPLE_SWITCH. (line 34) +* gimple_switch_set_label: GIMPLE_SWITCH. (line 42) +* gimple_switch_set_num_labels: GIMPLE_SWITCH. (line 27) +* GIMPLE_TRY: GIMPLE_TRY. (line 6) +* gimple_try_catch_is_cleanup: GIMPLE_TRY. (line 20) +* gimple_try_cleanup: GIMPLE_TRY. (line 27) +* gimple_try_eval: GIMPLE_TRY. (line 23) +* gimple_try_kind: GIMPLE_TRY. (line 16) +* gimple_try_set_catch_is_cleanup: GIMPLE_TRY. (line 32) +* gimple_try_set_cleanup: GIMPLE_TRY. (line 41) +* gimple_try_set_eval: GIMPLE_TRY. (line 36) +* gimple_use_ops: Manipulating GIMPLE statements. + (line 101) +* gimple_vdef_ops: Manipulating GIMPLE statements. + (line 115) +* gimple_visited_p: Manipulating GIMPLE statements. + (line 58) +* gimple_vuse_ops: Manipulating GIMPLE statements. + (line 108) +* gimple_wce_cleanup: GIMPLE_WITH_CLEANUP_EXPR. + (line 11) +* gimple_wce_cleanup_eh_only: GIMPLE_WITH_CLEANUP_EXPR. + (line 18) +* gimple_wce_set_cleanup: GIMPLE_WITH_CLEANUP_EXPR. + (line 15) +* gimple_wce_set_cleanup_eh_only: GIMPLE_WITH_CLEANUP_EXPR. + (line 22) +* GIMPLE_WITH_CLEANUP_EXPR: GIMPLE_WITH_CLEANUP_EXPR. + (line 6) +* gimplification <1>: Parsing pass. (line 14) +* gimplification: Gimplification pass. + (line 6) +* gimplifier: Parsing pass. (line 14) +* gimplify_assign: GIMPLE_ASSIGN. (line 19) +* gimplify_expr: Gimplification pass. + (line 18) +* gimplify_function_tree: Gimplification pass. + (line 18) +* GLOBAL_INIT_PRIORITY: Functions for C++. (line 141) +* global_regs: Register Basics. (line 59) +* GO_IF_LEGITIMATE_ADDRESS: Addressing Modes. (line 91) +* GO_IF_MODE_DEPENDENT_ADDRESS: Addressing Modes. (line 212) +* greater than: Comparisons. (line 60) +* gsi_after_labels: Sequence iterators. (line 76) +* gsi_bb: Sequence iterators. (line 83) +* gsi_commit_edge_inserts: Sequence iterators. (line 194) +* gsi_commit_one_edge_insert: Sequence iterators. (line 190) +* gsi_end_p: Sequence iterators. (line 60) +* gsi_for_stmt: Sequence iterators. (line 157) +* gsi_insert_after: Sequence iterators. (line 147) +* gsi_insert_before: Sequence iterators. (line 136) +* gsi_insert_on_edge: Sequence iterators. (line 174) +* gsi_insert_on_edge_immediate: Sequence iterators. (line 185) +* gsi_insert_seq_after: Sequence iterators. (line 154) +* gsi_insert_seq_before: Sequence iterators. (line 143) +* gsi_insert_seq_on_edge: Sequence iterators. (line 179) +* gsi_last: Sequence iterators. (line 50) +* gsi_last_bb: Sequence iterators. (line 56) +* gsi_link_after: Sequence iterators. (line 115) +* gsi_link_before: Sequence iterators. (line 105) +* gsi_link_seq_after: Sequence iterators. (line 110) +* gsi_link_seq_before: Sequence iterators. (line 99) +* gsi_move_after: Sequence iterators. (line 161) +* gsi_move_before: Sequence iterators. (line 166) +* gsi_move_to_bb_end: Sequence iterators. (line 171) +* gsi_next: Sequence iterators. (line 66) +* gsi_one_before_end_p: Sequence iterators. (line 63) +* gsi_prev: Sequence iterators. (line 69) +* gsi_remove: Sequence iterators. (line 90) +* gsi_replace: Sequence iterators. (line 130) +* gsi_seq: Sequence iterators. (line 86) +* gsi_split_seq_after: Sequence iterators. (line 120) +* gsi_split_seq_before: Sequence iterators. (line 125) +* gsi_start: Sequence iterators. (line 40) +* gsi_start_bb: Sequence iterators. (line 46) +* gsi_stmt: Sequence iterators. (line 72) +* gsi_stmt_ptr: Sequence iterators. (line 80) +* gt: Comparisons. (line 60) +* gt and attributes: Expressions. (line 64) +* GT_EXPR: Unary and Binary Expressions. + (line 6) +* gtu: Comparisons. (line 64) +* gtu and attributes: Expressions. (line 64) +* GTY: Type Information. (line 6) +* H in constraint: Simple Constraints. (line 98) +* HAmode: Machine Modes. (line 144) +* HANDLE_PRAGMA_PACK_WITH_EXPANSION: Misc. (line 438) +* HANDLER: Statements for C++. (line 6) +* HANDLER_BODY: Statements for C++. (line 6) +* HANDLER_PARMS: Statements for C++. (line 6) +* hard registers: Regs and Memory. (line 9) +* HARD_FRAME_POINTER_IS_ARG_POINTER: Frame Registers. (line 58) +* HARD_FRAME_POINTER_IS_FRAME_POINTER: Frame Registers. (line 51) +* HARD_FRAME_POINTER_REGNUM: Frame Registers. (line 20) +* HARD_REGNO_CALL_PART_CLOBBERED: Register Basics. (line 53) +* HARD_REGNO_CALLER_SAVE_MODE: Caller Saves. (line 20) +* HARD_REGNO_MODE_OK: Values in Registers. + (line 58) +* HARD_REGNO_NREGS: Values in Registers. + (line 11) +* HARD_REGNO_NREGS_HAS_PADDING: Values in Registers. + (line 25) +* HARD_REGNO_NREGS_WITH_PADDING: Values in Registers. + (line 43) +* HARD_REGNO_RENAME_OK: Values in Registers. + (line 119) +* HAS_INIT_SECTION: Macros for Initialization. + (line 19) +* HAS_LONG_COND_BRANCH: Misc. (line 9) +* HAS_LONG_UNCOND_BRANCH: Misc. (line 18) +* HAVE_DOS_BASED_FILE_SYSTEM: Filesystem. (line 11) +* HAVE_POST_DECREMENT: Addressing Modes. (line 12) +* HAVE_POST_INCREMENT: Addressing Modes. (line 11) +* HAVE_POST_MODIFY_DISP: Addressing Modes. (line 18) +* HAVE_POST_MODIFY_REG: Addressing Modes. (line 24) +* HAVE_PRE_DECREMENT: Addressing Modes. (line 10) +* HAVE_PRE_INCREMENT: Addressing Modes. (line 9) +* HAVE_PRE_MODIFY_DISP: Addressing Modes. (line 17) +* HAVE_PRE_MODIFY_REG: Addressing Modes. (line 23) +* HCmode: Machine Modes. (line 197) +* HFmode: Machine Modes. (line 58) +* high: Constants. (line 109) +* HImode: Machine Modes. (line 29) +* HImode, in insn: Insns. (line 272) +* HONOR_REG_ALLOC_ORDER: Allocation Order. (line 37) +* host configuration: Host Config. (line 6) +* host functions: Host Common. (line 6) +* host hooks: Host Common. (line 6) +* host makefile fragment: Host Fragment. (line 6) +* HOST_BIT_BUCKET: Filesystem. (line 51) +* HOST_EXECUTABLE_SUFFIX: Filesystem. (line 45) +* HOST_HOOKS_EXTRA_SIGNALS: Host Common. (line 12) +* HOST_HOOKS_GT_PCH_ALLOC_GRANULARITY: Host Common. (line 45) +* HOST_HOOKS_GT_PCH_GET_ADDRESS: Host Common. (line 17) +* HOST_HOOKS_GT_PCH_USE_ADDRESS: Host Common. (line 26) +* HOST_LACKS_INODE_NUMBERS: Filesystem. (line 89) +* HOST_LONG_FORMAT: Host Misc. (line 45) +* HOST_LONG_LONG_FORMAT: Host Misc. (line 41) +* HOST_OBJECT_SUFFIX: Filesystem. (line 40) +* HOST_PTR_PRINTF: Host Misc. (line 49) +* HOT_TEXT_SECTION_NAME: Sections. (line 43) +* HQmode: Machine Modes. (line 107) +* i in constraint: Simple Constraints. (line 70) +* I in constraint: Simple Constraints. (line 81) +* identifier: Identifiers. (line 6) +* IDENTIFIER_LENGTH: Identifiers. (line 22) +* IDENTIFIER_NODE: Identifiers. (line 6) +* IDENTIFIER_OPNAME_P: Identifiers. (line 27) +* IDENTIFIER_POINTER: Identifiers. (line 17) +* IDENTIFIER_TYPENAME_P: Identifiers. (line 33) +* IEEE 754-2008: Decimal float library routines. + (line 6) +* IF_COND: Statements for C++. (line 6) +* if_marked: GTY Options. (line 151) +* IF_STMT: Statements for C++. (line 6) +* if_then_else: Comparisons. (line 80) +* if_then_else and attributes: Expressions. (line 32) +* if_then_else usage: Side Effects. (line 56) +* IFCVT_EXTRA_FIELDS: Misc. (line 582) +* IFCVT_INIT_EXTRA_FIELDS: Misc. (line 577) +* IFCVT_MODIFY_CANCEL: Misc. (line 571) +* IFCVT_MODIFY_FINAL: Misc. (line 565) +* IFCVT_MODIFY_INSN: Misc. (line 559) +* IFCVT_MODIFY_MULTIPLE_TESTS: Misc. (line 552) +* IFCVT_MODIFY_TESTS: Misc. (line 541) +* IMAGPART_EXPR: Unary and Binary Expressions. + (line 6) +* Immediate Uses: SSA Operands. (line 274) +* immediate_operand: Machine-Independent Predicates. + (line 11) +* IMMEDIATE_PREFIX: Instruction Output. (line 155) +* in_struct: Flags. (line 263) +* in_struct, in code_label and note: Flags. (line 59) +* in_struct, in insn and jump_insn and call_insn: Flags. (line 49) +* in_struct, in insn, jump_insn and call_insn: Flags. (line 166) +* in_struct, in mem: Flags. (line 70) +* in_struct, in subreg: Flags. (line 205) +* include: Including Patterns. (line 6) +* INCLUDE_DEFAULTS: Driver. (line 344) +* inclusive-or, bitwise: Arithmetic. (line 163) +* INCOMING_FRAME_SP_OFFSET: Frame Layout. (line 183) +* INCOMING_REGNO: Register Basics. (line 88) +* INCOMING_RETURN_ADDR_RTX: Frame Layout. (line 139) +* INCOMING_STACK_BOUNDARY: Storage Layout. (line 153) +* INDEX_REG_CLASS: Register Classes. (line 136) +* indirect_jump instruction pattern: Standard Names. (line 1078) +* indirect_operand: Machine-Independent Predicates. + (line 71) +* INDIRECT_REF: Storage References. (line 6) +* INIT_ARRAY_SECTION_ASM_OP: Sections. (line 108) +* INIT_CUMULATIVE_ARGS: Register Arguments. (line 149) +* INIT_CUMULATIVE_INCOMING_ARGS: Register Arguments. (line 176) +* INIT_CUMULATIVE_LIBCALL_ARGS: Register Arguments. (line 170) +* INIT_ENVIRONMENT: Driver. (line 306) +* INIT_EXPANDERS: Per-Function Data. (line 39) +* INIT_EXPR: Unary and Binary Expressions. + (line 6) +* init_machine_status: Per-Function Data. (line 45) +* init_one_libfunc: Library Calls. (line 15) +* INIT_SECTION_ASM_OP <1>: Macros for Initialization. + (line 10) +* INIT_SECTION_ASM_OP: Sections. (line 92) +* INITIAL_ELIMINATION_OFFSET: Elimination. (line 85) +* INITIAL_FRAME_ADDRESS_RTX: Frame Layout. (line 83) +* INITIAL_FRAME_POINTER_OFFSET: Elimination. (line 35) +* initialization routines: Initialization. (line 6) +* inlining: Target Attributes. (line 95) +* insert_insn_on_edge: Maintaining the CFG. + (line 118) +* insn: Insns. (line 63) +* insn and /f: Flags. (line 125) +* insn and /j: Flags. (line 175) +* insn and /s: Flags. (line 166) +* insn and /u: Flags. (line 39) +* insn and /v: Flags. (line 44) +* insn attributes: Insn Attributes. (line 6) +* insn canonicalization: Insn Canonicalizations. + (line 6) +* insn includes: Including Patterns. (line 6) +* insn lengths, computing: Insn Lengths. (line 6) +* insn splitting: Insn Splitting. (line 6) +* insn-attr.h: Defining Attributes. + (line 24) +* INSN_ANNULLED_BRANCH_P: Flags. (line 39) +* INSN_CODE: Insns. (line 298) +* INSN_DELETED_P: Flags. (line 44) +* INSN_FROM_TARGET_P: Flags. (line 49) +* insn_list: Insns. (line 545) +* INSN_REFERENCES_ARE_DELAYED: Misc. (line 480) +* INSN_SETS_ARE_DELAYED: Misc. (line 469) +* INSN_UID: Insns. (line 23) +* INSN_VAR_LOCATION: Insns. (line 239) +* insns: Insns. (line 6) +* insns, generating: RTL Template. (line 6) +* insns, recognizing: RTL Template. (line 6) +* instruction attributes: Insn Attributes. (line 6) +* instruction latency time: Processor pipeline description. + (line 197) +* instruction patterns: Patterns. (line 6) +* instruction splitting: Insn Splitting. (line 6) +* insv instruction pattern: Standard Names. (line 893) +* INT16_TYPE: Type Layout. (line 236) +* INT32_TYPE: Type Layout. (line 237) +* INT64_TYPE: Type Layout. (line 238) +* INT8_TYPE: Type Layout. (line 235) +* INT_FAST16_TYPE: Type Layout. (line 252) +* INT_FAST32_TYPE: Type Layout. (line 253) +* INT_FAST64_TYPE: Type Layout. (line 254) +* INT_FAST8_TYPE: Type Layout. (line 251) +* INT_LEAST16_TYPE: Type Layout. (line 244) +* INT_LEAST32_TYPE: Type Layout. (line 245) +* INT_LEAST64_TYPE: Type Layout. (line 246) +* INT_LEAST8_TYPE: Type Layout. (line 243) +* INT_TYPE_SIZE: Type Layout. (line 12) +* INTEGER_CST: Constant expressions. + (line 6) +* INTEGER_TYPE: Types. (line 6) +* Interdependence of Patterns: Dependent Patterns. (line 6) +* interfacing to GCC output: Interface. (line 6) +* interlock delays: Processor pipeline description. + (line 6) +* intermediate representation lowering: Parsing pass. (line 14) +* INTMAX_TYPE: Type Layout. (line 212) +* INTPTR_TYPE: Type Layout. (line 259) +* introduction: Top. (line 6) +* INVOKE__main: Macros for Initialization. + (line 51) +* ior: Arithmetic. (line 163) +* ior and attributes: Expressions. (line 50) +* ior, canonicalization of: Insn Canonicalizations. + (line 52) +* iorM3 instruction pattern: Standard Names. (line 222) +* IRA_COVER_CLASSES: Register Classes. (line 564) +* IRA_HARD_REGNO_ADD_COST_MULTIPLIER: Allocation Order. (line 45) +* IS_ASM_LOGICAL_LINE_SEPARATOR: Data Output. (line 132) +* is_gimple_addressable: Logical Operators. (line 115) +* is_gimple_asm_val: Logical Operators. (line 119) +* is_gimple_assign: Logical Operators. (line 151) +* is_gimple_call: Logical Operators. (line 154) +* is_gimple_call_addr: Logical Operators. (line 122) +* is_gimple_constant: Logical Operators. (line 130) +* is_gimple_debug: Logical Operators. (line 157) +* is_gimple_ip_invariant: Logical Operators. (line 139) +* is_gimple_ip_invariant_address: Logical Operators. (line 144) +* is_gimple_mem_ref_addr: Logical Operators. (line 126) +* is_gimple_min_invariant: Logical Operators. (line 133) +* is_gimple_omp: GIMPLE_OMP_PARALLEL. + (line 65) +* is_gimple_val: Logical Operators. (line 109) +* iterators in .md files: Iterators. (line 6) +* IV analysis on GIMPLE: Scalar evolutions. (line 6) +* IV analysis on RTL: loop-iv. (line 6) +* jump: Flags. (line 314) +* jump instruction pattern: Standard Names. (line 969) +* jump instruction patterns: Jump Patterns. (line 6) +* jump instructions and set: Side Effects. (line 56) +* jump, in call_insn: Flags. (line 179) +* jump, in insn: Flags. (line 175) +* jump, in mem: Flags. (line 79) +* JUMP_ALIGN: Alignment Output. (line 9) +* jump_insn: Insns. (line 73) +* jump_insn and /f: Flags. (line 125) +* jump_insn and /s: Flags. (line 49) +* jump_insn and /u: Flags. (line 39) +* jump_insn and /v: Flags. (line 44) +* JUMP_LABEL: Insns. (line 80) +* JUMP_TABLES_IN_TEXT_SECTION: Sections. (line 152) +* Jumps: Jumps. (line 6) +* LABEL_ALIGN: Alignment Output. (line 58) +* LABEL_ALIGN_AFTER_BARRIER: Alignment Output. (line 27) +* LABEL_ALT_ENTRY_P: Insns. (line 140) +* LABEL_ALTERNATE_NAME: Edges. (line 180) +* LABEL_DECL: Declarations. (line 6) +* LABEL_KIND: Insns. (line 140) +* LABEL_NUSES: Insns. (line 136) +* LABEL_PRESERVE_P: Flags. (line 59) +* label_ref: Constants. (line 86) +* label_ref and /v: Flags. (line 65) +* label_ref, RTL sharing: Sharing. (line 35) +* LABEL_REF_NONLOCAL_P: Flags. (line 65) +* lang_hooks.gimplify_expr: Gimplification pass. + (line 18) +* lang_hooks.parse_file: Parsing pass. (line 6) +* language-dependent trees: Language-dependent trees. + (line 6) +* language-independent intermediate representation: Parsing pass. + (line 14) +* large return values: Aggregate Return. (line 6) +* LARGEST_EXPONENT_IS_NORMAL: Storage Layout. (line 470) +* LAST_STACK_REG: Stack Registers. (line 31) +* LAST_VIRTUAL_REGISTER: Regs and Memory. (line 51) +* lceilMN2: Standard Names. (line 624) +* LCSSA: LCSSA. (line 6) +* LD_FINI_SWITCH: Macros for Initialization. + (line 29) +* LD_INIT_SWITCH: Macros for Initialization. + (line 25) +* LDD_SUFFIX: Macros for Initialization. + (line 122) +* le: Comparisons. (line 76) +* le and attributes: Expressions. (line 64) +* LE_EXPR: Unary and Binary Expressions. + (line 6) +* leaf functions: Leaf Functions. (line 6) +* leaf_function_p: Standard Names. (line 1040) +* LEAF_REG_REMAP: Leaf Functions. (line 39) +* LEAF_REGISTERS: Leaf Functions. (line 25) +* left rotate: Arithmetic. (line 195) +* left shift: Arithmetic. (line 173) +* LEGITIMATE_CONSTANT_P: Addressing Modes. (line 230) +* LEGITIMATE_PIC_OPERAND_P: PIC. (line 32) +* LEGITIMIZE_RELOAD_ADDRESS: Addressing Modes. (line 151) +* length: GTY Options. (line 50) +* less than: Comparisons. (line 68) +* less than or equal: Comparisons. (line 76) +* leu: Comparisons. (line 76) +* leu and attributes: Expressions. (line 64) +* lfloorMN2: Standard Names. (line 619) +* LIB2FUNCS_EXTRA: Target Fragment. (line 11) +* LIB_SPEC: Driver. (line 108) +* LIBCALL_VALUE: Scalar Return. (line 56) +* libgcc.a: Library Calls. (line 6) +* LIBGCC2_CFLAGS: Target Fragment. (line 8) +* LIBGCC2_HAS_DF_MODE: Type Layout. (line 109) +* LIBGCC2_HAS_TF_MODE: Type Layout. (line 122) +* LIBGCC2_HAS_XF_MODE: Type Layout. (line 116) +* LIBGCC2_LONG_DOUBLE_TYPE_SIZE: Type Layout. (line 103) +* LIBGCC2_UNWIND_ATTRIBUTE: Misc. (line 960) +* LIBGCC_SPEC: Driver. (line 116) +* library subroutine names: Library Calls. (line 6) +* LIBRARY_PATH_ENV: Misc. (line 520) +* LIMIT_RELOAD_CLASS: Register Classes. (line 298) +* Linear loop transformations framework: Lambda. (line 6) +* LINK_COMMAND_SPEC: Driver. (line 237) +* LINK_EH_SPEC: Driver. (line 143) +* LINK_ELIMINATE_DUPLICATE_LDIRECTORIES: Driver. (line 247) +* LINK_GCC_C_SEQUENCE_SPEC: Driver. (line 233) +* LINK_LIBGCC_SPECIAL_1: Driver. (line 228) +* LINK_SPEC: Driver. (line 101) +* list: Containers. (line 6) +* Liveness representation: Liveness information. + (line 6) +* lo_sum: Arithmetic. (line 24) +* load address instruction: Simple Constraints. (line 164) +* LOAD_EXTEND_OP: Misc. (line 69) +* load_multiple instruction pattern: Standard Names. (line 137) +* LOCAL_ALIGNMENT: Storage Layout. (line 242) +* LOCAL_CLASS_P: Classes. (line 73) +* LOCAL_DECL_ALIGNMENT: Storage Layout. (line 272) +* LOCAL_INCLUDE_DIR: Driver. (line 313) +* LOCAL_LABEL_PREFIX: Instruction Output. (line 153) +* LOCAL_REGNO: Register Basics. (line 102) +* LOG_LINKS: Insns. (line 317) +* Logical Operators: Logical Operators. (line 6) +* logical-and, bitwise: Arithmetic. (line 158) +* logM2 instruction pattern: Standard Names. (line 532) +* LONG_ACCUM_TYPE_SIZE: Type Layout. (line 93) +* LONG_DOUBLE_TYPE_SIZE: Type Layout. (line 58) +* LONG_FRACT_TYPE_SIZE: Type Layout. (line 73) +* LONG_LONG_ACCUM_TYPE_SIZE: Type Layout. (line 98) +* LONG_LONG_FRACT_TYPE_SIZE: Type Layout. (line 78) +* LONG_LONG_TYPE_SIZE: Type Layout. (line 33) +* LONG_TYPE_SIZE: Type Layout. (line 22) +* longjmp and automatic variables: Interface. (line 52) +* Loop analysis: Loop representation. + (line 6) +* Loop manipulation: Loop manipulation. (line 6) +* Loop querying: Loop querying. (line 6) +* Loop representation: Loop representation. + (line 6) +* Loop-closed SSA form: LCSSA. (line 6) +* LOOP_ALIGN: Alignment Output. (line 41) +* LOOP_EXPR: Unary and Binary Expressions. + (line 6) +* looping instruction patterns: Looping Patterns. (line 6) +* lowering, language-dependent intermediate representation: Parsing pass. + (line 14) +* lrintMN2: Standard Names. (line 609) +* lroundMN2: Standard Names. (line 614) +* LSHIFT_EXPR: Unary and Binary Expressions. + (line 6) +* lshiftrt: Arithmetic. (line 190) +* lshiftrt and attributes: Expressions. (line 64) +* lshrM3 instruction pattern: Standard Names. (line 468) +* lt: Comparisons. (line 68) +* lt and attributes: Expressions. (line 64) +* LT_EXPR: Unary and Binary Expressions. + (line 6) +* LTGT_EXPR: Unary and Binary Expressions. + (line 6) +* lto: LTO. (line 6) +* ltrans: LTO. (line 6) +* ltu: Comparisons. (line 68) +* m in constraint: Simple Constraints. (line 17) +* machine attributes: Target Attributes. (line 6) +* machine description macros: Target Macros. (line 6) +* machine descriptions: Machine Desc. (line 6) +* machine mode conversions: Conversions. (line 6) +* machine modes: Machine Modes. (line 6) +* machine specific constraints: Machine Constraints. + (line 6) +* machine-independent predicates: Machine-Independent Predicates. + (line 6) +* macros, target description: Target Macros. (line 6) +* maddMN4 instruction pattern: Standard Names. (line 391) +* MAKE_DECL_ONE_ONLY: Label Output. (line 238) +* make_phi_node: GIMPLE_PHI. (line 7) +* make_safe_from: Expander Definitions. + (line 148) +* makefile fragment: Fragments. (line 6) +* makefile targets: Makefile. (line 6) +* MALLOC_ABI_ALIGNMENT: Storage Layout. (line 167) +* Manipulating GIMPLE statements: Manipulating GIMPLE statements. + (line 6) +* mark_hook: GTY Options. (line 166) +* marking roots: GGC Roots. (line 6) +* MASK_RETURN_ADDR: Exception Region Output. + (line 35) +* match_dup <1>: RTL Template. (line 73) +* match_dup: define_peephole2. (line 28) +* match_dup and attributes: Insn Lengths. (line 16) +* match_op_dup: RTL Template. (line 163) +* match_operand: RTL Template. (line 16) +* match_operand and attributes: Expressions. (line 55) +* match_operator: RTL Template. (line 95) +* match_par_dup: RTL Template. (line 219) +* match_parallel: RTL Template. (line 172) +* match_scratch <1>: define_peephole2. (line 28) +* match_scratch: RTL Template. (line 58) +* matching constraint: Simple Constraints. (line 142) +* matching operands: Output Template. (line 49) +* math library: Soft float library routines. + (line 6) +* math, in RTL: Arithmetic. (line 6) +* MATH_LIBRARY: Misc. (line 513) +* matherr: Library Calls. (line 44) +* MAX_BITS_PER_WORD: Storage Layout. (line 54) +* MAX_CONDITIONAL_EXECUTE: Misc. (line 535) +* MAX_FIXED_MODE_SIZE: Storage Layout. (line 417) +* MAX_MOVE_MAX: Misc. (line 120) +* MAX_OFILE_ALIGNMENT: Storage Layout. (line 204) +* MAX_REGS_PER_ADDRESS: Addressing Modes. (line 43) +* MAX_STACK_ALIGNMENT: Storage Layout. (line 197) +* maxM3 instruction pattern: Standard Names. (line 261) +* may_trap_p, tree_could_trap_p: Edges. (line 115) +* maybe_undef: GTY Options. (line 174) +* mcount: Profiling. (line 12) +* MD_CAN_REDIRECT_BRANCH: Misc. (line 682) +* MD_EXEC_PREFIX: Driver. (line 268) +* MD_FALLBACK_FRAME_STATE_FOR: Exception Handling. (line 98) +* MD_HANDLE_UNWABI: Exception Handling. (line 118) +* MD_STARTFILE_PREFIX: Driver. (line 296) +* MD_STARTFILE_PREFIX_1: Driver. (line 301) +* MD_UNWIND_SUPPORT: Exception Handling. (line 94) +* mem: Regs and Memory. (line 374) +* mem and /c: Flags. (line 99) +* mem and /f: Flags. (line 103) +* mem and /i: Flags. (line 85) +* mem and /j: Flags. (line 79) +* mem and /s: Flags. (line 70) +* mem and /u: Flags. (line 152) +* mem and /v: Flags. (line 94) +* mem, RTL sharing: Sharing. (line 40) +* MEM_ADDR_SPACE: Special Accessors. (line 39) +* MEM_ALIAS_SET: Special Accessors. (line 9) +* MEM_ALIGN: Special Accessors. (line 36) +* MEM_EXPR: Special Accessors. (line 20) +* MEM_IN_STRUCT_P: Flags. (line 70) +* MEM_KEEP_ALIAS_SET_P: Flags. (line 79) +* MEM_NOTRAP_P: Flags. (line 99) +* MEM_OFFSET: Special Accessors. (line 28) +* MEM_POINTER: Flags. (line 103) +* MEM_READONLY_P: Flags. (line 152) +* MEM_REF: Storage References. (line 6) +* MEM_SCALAR_P: Flags. (line 85) +* MEM_SIZE: Special Accessors. (line 31) +* MEM_VOLATILE_P: Flags. (line 94) +* MEMBER_TYPE_FORCES_BLK: Storage Layout. (line 397) +* memory model: Memory model. (line 6) +* memory reference, nonoffsettable: Simple Constraints. (line 256) +* memory references in constraints: Simple Constraints. (line 17) +* memory_barrier instruction pattern: Standard Names. (line 1422) +* MEMORY_MOVE_COST: Costs. (line 54) +* memory_operand: Machine-Independent Predicates. + (line 58) +* METHOD_TYPE: Types. (line 6) +* MIN_UNITS_PER_WORD: Storage Layout. (line 64) +* MINIMUM_ALIGNMENT: Storage Layout. (line 285) +* MINIMUM_ATOMIC_ALIGNMENT: Storage Layout. (line 175) +* minM3 instruction pattern: Standard Names. (line 261) +* minus: Arithmetic. (line 36) +* minus and attributes: Expressions. (line 64) +* minus, canonicalization of: Insn Canonicalizations. + (line 27) +* MINUS_EXPR: Unary and Binary Expressions. + (line 6) +* MIPS coprocessor-definition macros: MIPS Coprocessors. (line 6) +* mod: Arithmetic. (line 136) +* mod and attributes: Expressions. (line 64) +* mode classes: Machine Modes. (line 219) +* mode iterators in .md files: Mode Iterators. (line 6) +* mode switching: Mode Switching. (line 6) +* MODE_ACCUM: Machine Modes. (line 249) +* MODE_AFTER: Mode Switching. (line 49) +* MODE_BASE_REG_CLASS: Register Classes. (line 114) +* MODE_BASE_REG_REG_CLASS: Register Classes. (line 120) +* MODE_CC <1>: Machine Modes. (line 268) +* MODE_CC: MODE_CC Condition Codes. + (line 6) +* MODE_CODE_BASE_REG_CLASS: Register Classes. (line 127) +* MODE_COMPLEX_FLOAT: Machine Modes. (line 260) +* MODE_COMPLEX_INT: Machine Modes. (line 257) +* MODE_DECIMAL_FLOAT: Machine Modes. (line 237) +* MODE_ENTRY: Mode Switching. (line 54) +* MODE_EXIT: Mode Switching. (line 60) +* MODE_FLOAT: Machine Modes. (line 233) +* MODE_FRACT: Machine Modes. (line 241) +* MODE_FUNCTION: Machine Modes. (line 264) +* MODE_INT: Machine Modes. (line 225) +* MODE_NEEDED: Mode Switching. (line 42) +* MODE_PARTIAL_INT: Machine Modes. (line 229) +* MODE_PRIORITY_TO_MODE: Mode Switching. (line 66) +* MODE_RANDOM: Machine Modes. (line 273) +* MODE_UACCUM: Machine Modes. (line 253) +* MODE_UFRACT: Machine Modes. (line 245) +* MODES_TIEABLE_P: Values in Registers. + (line 129) +* modifiers in constraints: Modifiers. (line 6) +* MODIFY_EXPR: Unary and Binary Expressions. + (line 6) +* MODIFY_JNI_METHOD_CALL: Misc. (line 760) +* modM3 instruction pattern: Standard Names. (line 222) +* modulo scheduling: RTL passes. (line 131) +* MOVE_BY_PIECES_P: Costs. (line 165) +* MOVE_MAX: Misc. (line 115) +* MOVE_MAX_PIECES: Costs. (line 171) +* MOVE_RATIO: Costs. (line 149) +* movM instruction pattern: Standard Names. (line 11) +* movmemM instruction pattern: Standard Names. (line 681) +* movmisalignM instruction pattern: Standard Names. (line 126) +* movMODEcc instruction pattern: Standard Names. (line 904) +* movstr instruction pattern: Standard Names. (line 716) +* movstrictM instruction pattern: Standard Names. (line 120) +* msubMN4 instruction pattern: Standard Names. (line 414) +* mulhisi3 instruction pattern: Standard Names. (line 367) +* mulM3 instruction pattern: Standard Names. (line 222) +* mulqihi3 instruction pattern: Standard Names. (line 371) +* mulsidi3 instruction pattern: Standard Names. (line 371) +* mult: Arithmetic. (line 92) +* mult and attributes: Expressions. (line 64) +* mult, canonicalization of: Insn Canonicalizations. + (line 27) +* MULT_EXPR: Unary and Binary Expressions. + (line 6) +* MULTILIB_DEFAULTS: Driver. (line 253) +* MULTILIB_DIRNAMES: Target Fragment. (line 64) +* MULTILIB_EXCEPTIONS: Target Fragment. (line 84) +* MULTILIB_EXTRA_OPTS: Target Fragment. (line 96) +* MULTILIB_MATCHES: Target Fragment. (line 77) +* MULTILIB_OPTIONS: Target Fragment. (line 44) +* multiple alternative constraints: Multi-Alternative. (line 6) +* MULTIPLE_SYMBOL_SPACES: Misc. (line 493) +* multiplication: Arithmetic. (line 92) +* multiplication with signed saturation: Arithmetic. (line 92) +* multiplication with unsigned saturation: Arithmetic. (line 92) +* n in constraint: Simple Constraints. (line 75) +* N_REG_CLASSES: Register Classes. (line 78) +* name: Identifiers. (line 6) +* named address spaces: Named Address Spaces. + (line 6) +* named patterns and conditions: Patterns. (line 47) +* names, pattern: Standard Names. (line 6) +* namespace, scope: Namespaces. (line 6) +* NAMESPACE_DECL <1>: Declarations. (line 6) +* NAMESPACE_DECL: Namespaces. (line 6) +* NATIVE_SYSTEM_HEADER_DIR: Target Fragment. (line 103) +* ne: Comparisons. (line 56) +* ne and attributes: Expressions. (line 64) +* NE_EXPR: Unary and Binary Expressions. + (line 6) +* nearbyintM2 instruction pattern: Standard Names. (line 591) +* neg: Arithmetic. (line 81) +* neg and attributes: Expressions. (line 64) +* neg, canonicalization of: Insn Canonicalizations. + (line 27) +* NEGATE_EXPR: Unary and Binary Expressions. + (line 6) +* negation: Arithmetic. (line 81) +* negation with signed saturation: Arithmetic. (line 81) +* negation with unsigned saturation: Arithmetic. (line 81) +* negM2 instruction pattern: Standard Names. (line 476) +* nested functions, trampolines for: Trampolines. (line 6) +* nested_ptr: GTY Options. (line 181) +* next_bb, prev_bb, FOR_EACH_BB: Basic Blocks. (line 10) +* NEXT_INSN: Insns. (line 30) +* NEXT_OBJC_RUNTIME: Library Calls. (line 80) +* nil: RTL Objects. (line 73) +* NM_FLAGS: Macros for Initialization. + (line 111) +* NO_DBX_BNSYM_ENSYM: DBX Hooks. (line 39) +* NO_DBX_FUNCTION_END: DBX Hooks. (line 33) +* NO_DBX_GCC_MARKER: File Names and DBX. (line 28) +* NO_DBX_MAIN_SOURCE_DIRECTORY: File Names and DBX. (line 23) +* NO_DOLLAR_IN_LABEL: Misc. (line 457) +* NO_DOT_IN_LABEL: Misc. (line 463) +* NO_FUNCTION_CSE: Costs. (line 261) +* NO_IMPLICIT_EXTERN_C: Misc. (line 376) +* NO_PROFILE_COUNTERS: Profiling. (line 28) +* NO_REGS: Register Classes. (line 17) +* NON_LVALUE_EXPR: Unary and Binary Expressions. + (line 6) +* nondeterministic finite state automaton: Processor pipeline description. + (line 301) +* nonimmediate_operand: Machine-Independent Predicates. + (line 101) +* nonlocal goto handler: Edges. (line 171) +* nonlocal_goto instruction pattern: Standard Names. (line 1262) +* nonlocal_goto_receiver instruction pattern: Standard Names. + (line 1279) +* nonmemory_operand: Machine-Independent Predicates. + (line 97) +* nonoffsettable memory reference: Simple Constraints. (line 256) +* nop instruction pattern: Standard Names. (line 1073) +* NOP_EXPR: Unary and Binary Expressions. + (line 6) +* normal predicates: Predicates. (line 31) +* not: Arithmetic. (line 154) +* not and attributes: Expressions. (line 50) +* not equal: Comparisons. (line 56) +* not, canonicalization of: Insn Canonicalizations. + (line 27) +* note: Insns. (line 168) +* note and /i: Flags. (line 59) +* note and /v: Flags. (line 44) +* NOTE_INSN_BASIC_BLOCK, CODE_LABEL, notes: Basic Blocks. (line 41) +* NOTE_INSN_BLOCK_BEG: Insns. (line 193) +* NOTE_INSN_BLOCK_END: Insns. (line 193) +* NOTE_INSN_DELETED: Insns. (line 183) +* NOTE_INSN_DELETED_LABEL: Insns. (line 188) +* NOTE_INSN_EH_REGION_BEG: Insns. (line 199) +* NOTE_INSN_EH_REGION_END: Insns. (line 199) +* NOTE_INSN_FUNCTION_BEG: Insns. (line 223) +* NOTE_INSN_LOOP_BEG: Insns. (line 207) +* NOTE_INSN_LOOP_CONT: Insns. (line 213) +* NOTE_INSN_LOOP_END: Insns. (line 207) +* NOTE_INSN_LOOP_VTOP: Insns. (line 217) +* NOTE_INSN_VAR_LOCATION: Insns. (line 227) +* NOTE_LINE_NUMBER: Insns. (line 168) +* NOTE_SOURCE_FILE: Insns. (line 168) +* NOTE_VAR_LOCATION: Insns. (line 227) +* NOTICE_UPDATE_CC: CC0 Condition Codes. + (line 31) +* NUM_MACHINE_MODES: Machine Modes. (line 286) +* NUM_MODES_FOR_MODE_SWITCHING: Mode Switching. (line 30) +* Number of iterations analysis: Number of iterations. + (line 6) +* o in constraint: Simple Constraints. (line 23) +* OBJC_GEN_METHOD_LABEL: Label Output. (line 440) +* OBJC_JBLEN: Misc. (line 955) +* OBJECT_FORMAT_COFF: Macros for Initialization. + (line 97) +* OFFSET_TYPE: Types. (line 6) +* offsettable address: Simple Constraints. (line 23) +* OImode: Machine Modes. (line 51) +* Omega a solver for linear programming problems: Omega. (line 6) +* OMP_ATOMIC: OpenMP. (line 6) +* OMP_CLAUSE: OpenMP. (line 6) +* OMP_CONTINUE: OpenMP. (line 6) +* OMP_CRITICAL: OpenMP. (line 6) +* OMP_FOR: OpenMP. (line 6) +* OMP_MASTER: OpenMP. (line 6) +* OMP_ORDERED: OpenMP. (line 6) +* OMP_PARALLEL: OpenMP. (line 6) +* OMP_RETURN: OpenMP. (line 6) +* OMP_SECTION: OpenMP. (line 6) +* OMP_SECTIONS: OpenMP. (line 6) +* OMP_SINGLE: OpenMP. (line 6) +* one_cmplM2 instruction pattern: Standard Names. (line 678) +* operand access: Accessors. (line 6) +* Operand Access Routines: SSA Operands. (line 119) +* operand constraints: Constraints. (line 6) +* Operand Iterators: SSA Operands. (line 119) +* operand predicates: Predicates. (line 6) +* operand substitution: Output Template. (line 6) +* Operands: Operands. (line 6) +* operands <1>: SSA Operands. (line 6) +* operands: Patterns. (line 53) +* operator predicates: Predicates. (line 6) +* optc-gen.awk: Options. (line 6) +* Optimization infrastructure for GIMPLE: Tree SSA. (line 6) +* OPTIMIZE_MODE_SWITCHING: Mode Switching. (line 9) +* option specification files: Options. (line 6) +* OPTION_DEFAULT_SPECS: Driver. (line 26) +* optional hardware or system features: Run-time Target. (line 59) +* options, directory search: Including Patterns. (line 44) +* order of register allocation: Allocation Order. (line 6) +* ordered_comparison_operator: Machine-Independent Predicates. + (line 116) +* ORDERED_EXPR: Unary and Binary Expressions. + (line 6) +* Ordering of Patterns: Pattern Ordering. (line 6) +* ORIGINAL_REGNO: Special Accessors. (line 44) +* other register constraints: Simple Constraints. (line 173) +* OUTGOING_REG_PARM_STACK_SPACE: Stack Arguments. (line 74) +* OUTGOING_REGNO: Register Basics. (line 95) +* output of assembler code: File Framework. (line 6) +* output statements: Output Statement. (line 6) +* output templates: Output Template. (line 6) +* OUTPUT_ADDR_CONST_EXTRA: Data Output. (line 51) +* output_asm_insn: Output Statement. (line 53) +* OUTPUT_QUOTED_STRING: File Framework. (line 102) +* OVERLAPPING_REGISTER_NAMES: Instruction Output. (line 21) +* OVERLOAD: Functions for C++. (line 6) +* OVERRIDE_ABI_FORMAT: Register Arguments. (line 140) +* OVL_CURRENT: Functions for C++. (line 6) +* OVL_NEXT: Functions for C++. (line 6) +* p in constraint: Simple Constraints. (line 164) +* PAD_VARARGS_DOWN: Register Arguments. (line 220) +* parallel: Side Effects. (line 204) +* param_is: GTY Options. (line 109) +* parameters, c++ abi: C++ ABI. (line 6) +* parameters, miscellaneous: Misc. (line 6) +* parameters, precompiled headers: PCH Target. (line 6) +* paramN_is: GTY Options. (line 127) +* parity: Arithmetic. (line 237) +* parityM2 instruction pattern: Standard Names. (line 672) +* PARM_BOUNDARY: Storage Layout. (line 132) +* PARM_DECL: Declarations. (line 6) +* PARSE_LDD_OUTPUT: Macros for Initialization. + (line 127) +* passes and files of the compiler: Passes. (line 6) +* passing arguments: Interface. (line 36) +* PATH_SEPARATOR: Filesystem. (line 31) +* PATTERN: Insns. (line 288) +* pattern conditions: Patterns. (line 43) +* pattern names: Standard Names. (line 6) +* Pattern Ordering: Pattern Ordering. (line 6) +* patterns: Patterns. (line 6) +* pc: Regs and Memory. (line 361) +* pc and attributes: Insn Lengths. (line 20) +* pc, RTL sharing: Sharing. (line 25) +* PC_REGNUM: Register Basics. (line 109) +* pc_rtx: Regs and Memory. (line 366) +* PCC_BITFIELD_TYPE_MATTERS: Storage Layout. (line 311) +* PCC_STATIC_STRUCT_RETURN: Aggregate Return. (line 65) +* PDImode: Machine Modes. (line 40) +* peephole optimization, RTL representation: Side Effects. (line 238) +* peephole optimizer definitions: Peephole Definitions. + (line 6) +* per-function data: Per-Function Data. (line 6) +* percent sign: Output Template. (line 6) +* PHI nodes: SSA. (line 31) +* PHI_ARG_DEF: SSA. (line 71) +* PHI_ARG_EDGE: SSA. (line 68) +* PHI_ARG_ELT: SSA. (line 63) +* PHI_NUM_ARGS: SSA. (line 59) +* PHI_RESULT: SSA. (line 56) +* PIC: PIC. (line 6) +* PIC_OFFSET_TABLE_REG_CALL_CLOBBERED: PIC. (line 26) +* PIC_OFFSET_TABLE_REGNUM: PIC. (line 16) +* pipeline hazard recognizer: Processor pipeline description. + (line 6) +* Plugins: Plugins. (line 6) +* plus: Arithmetic. (line 14) +* plus and attributes: Expressions. (line 64) +* plus, canonicalization of: Insn Canonicalizations. + (line 27) +* PLUS_EXPR: Unary and Binary Expressions. + (line 6) +* Pmode: Misc. (line 344) +* pmode_register_operand: Machine-Independent Predicates. + (line 35) +* pointer: Types. (line 6) +* POINTER_PLUS_EXPR: Unary and Binary Expressions. + (line 6) +* POINTER_SIZE: Storage Layout. (line 70) +* POINTER_TYPE: Types. (line 6) +* POINTERS_EXTEND_UNSIGNED: Storage Layout. (line 76) +* pop_operand: Machine-Independent Predicates. + (line 88) +* popcount: Arithmetic. (line 233) +* popcountM2 instruction pattern: Standard Names. (line 666) +* portability: Portability. (line 6) +* position independent code: PIC. (line 6) +* post_dec: Incdec. (line 25) +* post_inc: Incdec. (line 30) +* post_modify: Incdec. (line 33) +* POSTDECREMENT_EXPR: Unary and Binary Expressions. + (line 6) +* POSTINCREMENT_EXPR: Unary and Binary Expressions. + (line 6) +* POWI_MAX_MULTS: Misc. (line 823) +* powM3 instruction pattern: Standard Names. (line 540) +* pragma: Misc. (line 381) +* pre_dec: Incdec. (line 8) +* PRE_GCC3_DWARF_FRAME_REGISTERS: Frame Registers. (line 127) +* pre_inc: Incdec. (line 22) +* pre_modify: Incdec. (line 51) +* PREDECREMENT_EXPR: Unary and Binary Expressions. + (line 6) +* predefined macros: Run-time Target. (line 6) +* predicates: Predicates. (line 6) +* predicates and machine modes: Predicates. (line 31) +* predication <1>: Cond Exec Macros. (line 6) +* predication: Conditional Execution. + (line 6) +* predict.def: Profile information. + (line 24) +* PREFERRED_DEBUGGING_TYPE: All Debuggers. (line 42) +* PREFERRED_OUTPUT_RELOAD_CLASS: Register Classes. (line 278) +* PREFERRED_RELOAD_CLASS: Register Classes. (line 243) +* PREFERRED_STACK_BOUNDARY: Storage Layout. (line 146) +* prefetch: Side Effects. (line 312) +* prefetch and /v: Flags. (line 232) +* prefetch instruction pattern: Standard Names. (line 1401) +* PREFETCH_SCHEDULE_BARRIER_P: Flags. (line 232) +* PREINCREMENT_EXPR: Unary and Binary Expressions. + (line 6) +* presence_set: Processor pipeline description. + (line 220) +* preserving SSA form: SSA. (line 76) +* preserving virtual SSA form: SSA. (line 186) +* prev_active_insn: define_peephole. (line 60) +* PREV_INSN: Insns. (line 26) +* PRINT_OPERAND: Instruction Output. (line 96) +* PRINT_OPERAND_ADDRESS: Instruction Output. (line 124) +* PRINT_OPERAND_PUNCT_VALID_P: Instruction Output. (line 117) +* probe_stack instruction pattern: Standard Names. (line 1254) +* processor functional units: Processor pipeline description. + (line 6) +* processor pipeline description: Processor pipeline description. + (line 6) +* product: Arithmetic. (line 92) +* profile feedback: Profile information. + (line 14) +* profile representation: Profile information. + (line 6) +* PROFILE_BEFORE_PROLOGUE: Profiling. (line 35) +* PROFILE_HOOK: Profiling. (line 23) +* profiling, code generation: Profiling. (line 6) +* program counter: Regs and Memory. (line 362) +* prologue: Function Entry. (line 6) +* prologue instruction pattern: Standard Names. (line 1345) +* PROMOTE_MODE: Storage Layout. (line 87) +* pseudo registers: Regs and Memory. (line 9) +* PSImode: Machine Modes. (line 32) +* PTRDIFF_TYPE: Type Layout. (line 183) +* purge_dead_edges <1>: Edges. (line 104) +* purge_dead_edges: Maintaining the CFG. + (line 93) +* push address instruction: Simple Constraints. (line 164) +* PUSH_ARGS: Stack Arguments. (line 18) +* PUSH_ARGS_REVERSED: Stack Arguments. (line 26) +* push_operand: Machine-Independent Predicates. + (line 81) +* push_reload: Addressing Modes. (line 175) +* PUSH_ROUNDING: Stack Arguments. (line 32) +* pushM1 instruction pattern: Standard Names. (line 209) +* PUT_CODE: RTL Objects. (line 47) +* PUT_MODE: Machine Modes. (line 283) +* PUT_REG_NOTE_KIND: Insns. (line 350) +* PUT_SDB_: SDB and DWARF. (line 101) +* QCmode: Machine Modes. (line 197) +* QFmode: Machine Modes. (line 54) +* QImode: Machine Modes. (line 25) +* QImode, in insn: Insns. (line 272) +* QQmode: Machine Modes. (line 103) +* qualified type <1>: Types for C++. (line 6) +* qualified type: Types. (line 6) +* querying function unit reservations: Processor pipeline description. + (line 90) +* question mark: Multi-Alternative. (line 41) +* quotient: Arithmetic. (line 116) +* r in constraint: Simple Constraints. (line 66) +* RANGE_TEST_NON_SHORT_CIRCUIT: Costs. (line 265) +* RDIV_EXPR: Unary and Binary Expressions. + (line 6) +* READONLY_DATA_SECTION_ASM_OP: Sections. (line 63) +* real operands: SSA Operands. (line 6) +* REAL_ARITHMETIC: Floating Point. (line 66) +* REAL_CST: Constant expressions. + (line 6) +* REAL_LIBGCC_SPEC: Driver. (line 125) +* REAL_NM_FILE_NAME: Macros for Initialization. + (line 106) +* REAL_TYPE: Types. (line 6) +* REAL_VALUE_ABS: Floating Point. (line 82) +* REAL_VALUE_ATOF: Floating Point. (line 50) +* REAL_VALUE_FIX: Floating Point. (line 41) +* REAL_VALUE_FROM_INT: Floating Point. (line 99) +* REAL_VALUE_ISINF: Floating Point. (line 59) +* REAL_VALUE_ISNAN: Floating Point. (line 62) +* REAL_VALUE_NEGATE: Floating Point. (line 79) +* REAL_VALUE_NEGATIVE: Floating Point. (line 56) +* REAL_VALUE_TO_INT: Floating Point. (line 93) +* REAL_VALUE_TO_TARGET_DECIMAL128: Data Output. (line 156) +* REAL_VALUE_TO_TARGET_DECIMAL32: Data Output. (line 154) +* REAL_VALUE_TO_TARGET_DECIMAL64: Data Output. (line 155) +* REAL_VALUE_TO_TARGET_DOUBLE: Data Output. (line 152) +* REAL_VALUE_TO_TARGET_LONG_DOUBLE: Data Output. (line 153) +* REAL_VALUE_TO_TARGET_SINGLE: Data Output. (line 151) +* REAL_VALUE_TRUNCATE: Floating Point. (line 86) +* REAL_VALUE_TYPE: Floating Point. (line 26) +* REAL_VALUE_UNSIGNED_FIX: Floating Point. (line 45) +* REAL_VALUES_EQUAL: Floating Point. (line 32) +* REAL_VALUES_LESS: Floating Point. (line 38) +* REALPART_EXPR: Unary and Binary Expressions. + (line 6) +* recog_data.operand: Instruction Output. (line 54) +* recognizing insns: RTL Template. (line 6) +* RECORD_TYPE <1>: Types. (line 6) +* RECORD_TYPE: Classes. (line 6) +* redirect_edge_and_branch: Profile information. + (line 71) +* redirect_edge_and_branch, redirect_jump: Maintaining the CFG. + (line 103) +* reduc_smax_M instruction pattern: Standard Names. (line 267) +* reduc_smin_M instruction pattern: Standard Names. (line 267) +* reduc_splus_M instruction pattern: Standard Names. (line 279) +* reduc_umax_M instruction pattern: Standard Names. (line 273) +* reduc_umin_M instruction pattern: Standard Names. (line 273) +* reduc_uplus_M instruction pattern: Standard Names. (line 285) +* reference: Types. (line 6) +* REFERENCE_TYPE: Types. (line 6) +* reg: Regs and Memory. (line 9) +* reg and /f: Flags. (line 112) +* reg and /i: Flags. (line 107) +* reg and /v: Flags. (line 116) +* reg, RTL sharing: Sharing. (line 17) +* REG_ALLOC_ORDER: Allocation Order. (line 9) +* REG_BR_PRED: Insns. (line 531) +* REG_BR_PROB: Insns. (line 525) +* REG_BR_PROB_BASE, BB_FREQ_BASE, count: Profile information. + (line 82) +* REG_BR_PROB_BASE, EDGE_FREQUENCY: Profile information. + (line 52) +* REG_CC_SETTER: Insns. (line 496) +* REG_CC_USER: Insns. (line 496) +* reg_class_contents: Register Basics. (line 59) +* REG_CLASS_CONTENTS: Register Classes. (line 88) +* REG_CLASS_FROM_CONSTRAINT: Old Constraints. (line 35) +* REG_CLASS_FROM_LETTER: Old Constraints. (line 27) +* REG_CLASS_NAMES: Register Classes. (line 83) +* REG_CROSSING_JUMP: Insns. (line 409) +* REG_DEAD: Insns. (line 361) +* REG_DEAD, REG_UNUSED: Liveness information. + (line 32) +* REG_DEP_ANTI: Insns. (line 518) +* REG_DEP_OUTPUT: Insns. (line 514) +* REG_DEP_TRUE: Insns. (line 511) +* REG_EH_REGION, EDGE_ABNORMAL_CALL: Edges. (line 110) +* REG_EQUAL: Insns. (line 424) +* REG_EQUIV: Insns. (line 424) +* REG_EXPR: Special Accessors. (line 50) +* REG_FRAME_RELATED_EXPR: Insns. (line 537) +* REG_FUNCTION_VALUE_P: Flags. (line 107) +* REG_INC: Insns. (line 377) +* reg_label and /v: Flags. (line 65) +* REG_LABEL_OPERAND: Insns. (line 391) +* REG_LABEL_TARGET: Insns. (line 400) +* reg_names <1>: Instruction Output. (line 108) +* reg_names: Register Basics. (line 59) +* REG_NONNEG: Insns. (line 383) +* REG_NOTE_KIND: Insns. (line 350) +* REG_NOTES: Insns. (line 324) +* REG_OFFSET: Special Accessors. (line 54) +* REG_OK_STRICT: Addressing Modes. (line 100) +* REG_PARM_STACK_SPACE: Stack Arguments. (line 59) +* REG_PARM_STACK_SPACE, and FUNCTION_ARG: Register Arguments. + (line 52) +* REG_POINTER: Flags. (line 112) +* REG_SETJMP: Insns. (line 418) +* REG_UNUSED: Insns. (line 370) +* REG_USERVAR_P: Flags. (line 116) +* regclass_for_constraint: C Constraint Interface. + (line 60) +* register allocation order: Allocation Order. (line 6) +* register class definitions: Register Classes. (line 6) +* register class preference constraints: Class Preferences. (line 6) +* register pairs: Values in Registers. + (line 69) +* Register Transfer Language (RTL): RTL. (line 6) +* register usage: Registers. (line 6) +* REGISTER_MOVE_COST: Costs. (line 10) +* REGISTER_NAMES: Instruction Output. (line 9) +* register_operand: Machine-Independent Predicates. + (line 30) +* REGISTER_PREFIX: Instruction Output. (line 152) +* REGISTER_TARGET_PRAGMAS: Misc. (line 382) +* registers arguments: Register Arguments. (line 6) +* registers in constraints: Simple Constraints. (line 66) +* REGMODE_NATURAL_SIZE: Values in Registers. + (line 50) +* REGNO_MODE_CODE_OK_FOR_BASE_P: Register Classes. (line 169) +* REGNO_MODE_OK_FOR_BASE_P: Register Classes. (line 146) +* REGNO_MODE_OK_FOR_REG_BASE_P: Register Classes. (line 156) +* REGNO_OK_FOR_BASE_P: Register Classes. (line 142) +* REGNO_OK_FOR_INDEX_P: Register Classes. (line 180) +* REGNO_REG_CLASS: Register Classes. (line 103) +* regs_ever_live: Function Entry. (line 21) +* regular expressions: Processor pipeline description. + (line 106) +* relative costs: Costs. (line 6) +* RELATIVE_PREFIX_NOT_LINKDIR: Driver. (line 263) +* reload_completed: Standard Names. (line 1040) +* reload_in instruction pattern: Standard Names. (line 99) +* reload_in_progress: Standard Names. (line 57) +* reload_out instruction pattern: Standard Names. (line 99) +* reloading: RTL passes. (line 182) +* remainder: Arithmetic. (line 136) +* remainderM3 instruction pattern: Standard Names. (line 499) +* reorder: GTY Options. (line 205) +* representation of RTL: RTL. (line 6) +* reservation delays: Processor pipeline description. + (line 6) +* rest_of_decl_compilation: Parsing pass. (line 52) +* rest_of_type_compilation: Parsing pass. (line 52) +* restore_stack_block instruction pattern: Standard Names. (line 1174) +* restore_stack_function instruction pattern: Standard Names. + (line 1174) +* restore_stack_nonlocal instruction pattern: Standard Names. + (line 1174) +* RESULT_DECL: Declarations. (line 6) +* return: Side Effects. (line 72) +* return instruction pattern: Standard Names. (line 1027) +* return values in registers: Scalar Return. (line 6) +* RETURN_ADDR_IN_PREVIOUS_FRAME: Frame Layout. (line 135) +* RETURN_ADDR_OFFSET: Exception Handling. (line 60) +* RETURN_ADDR_RTX: Frame Layout. (line 124) +* RETURN_ADDRESS_POINTER_REGNUM: Frame Registers. (line 65) +* RETURN_EXPR: Statements for C++. (line 6) +* RETURN_STMT: Statements for C++. (line 6) +* return_val: Flags. (line 299) +* return_val, in call_insn: Flags. (line 24) +* return_val, in mem: Flags. (line 85) +* return_val, in reg: Flags. (line 107) +* return_val, in symbol_ref: Flags. (line 220) +* returning aggregate values: Aggregate Return. (line 6) +* returning structures and unions: Interface. (line 10) +* reverse probability: Profile information. + (line 66) +* REVERSE_CONDEXEC_PREDICATES_P: Cond Exec Macros. (line 11) +* REVERSE_CONDITION: MODE_CC Condition Codes. + (line 87) +* REVERSIBLE_CC_MODE: MODE_CC Condition Codes. + (line 73) +* right rotate: Arithmetic. (line 195) +* right shift: Arithmetic. (line 190) +* rintM2 instruction pattern: Standard Names. (line 599) +* RISC: Processor pipeline description. + (line 220) +* roots, marking: GGC Roots. (line 6) +* rotate: Arithmetic. (line 195) +* rotatert: Arithmetic. (line 195) +* rotlM3 instruction pattern: Standard Names. (line 468) +* rotrM3 instruction pattern: Standard Names. (line 468) +* ROUND_DIV_EXPR: Unary and Binary Expressions. + (line 6) +* ROUND_MOD_EXPR: Unary and Binary Expressions. + (line 6) +* ROUND_TOWARDS_ZERO: Storage Layout. (line 461) +* ROUND_TYPE_ALIGN: Storage Layout. (line 408) +* roundM2 instruction pattern: Standard Names. (line 575) +* RSHIFT_EXPR: Unary and Binary Expressions. + (line 6) +* RTL addition: Arithmetic. (line 14) +* RTL addition with signed saturation: Arithmetic. (line 14) +* RTL addition with unsigned saturation: Arithmetic. (line 14) +* RTL classes: RTL Classes. (line 6) +* RTL comparison: Arithmetic. (line 43) +* RTL comparison operations: Comparisons. (line 6) +* RTL constant expression types: Constants. (line 6) +* RTL constants: Constants. (line 6) +* RTL declarations: RTL Declarations. (line 6) +* RTL difference: Arithmetic. (line 36) +* RTL expression: RTL Objects. (line 6) +* RTL expressions for arithmetic: Arithmetic. (line 6) +* RTL format: RTL Classes. (line 72) +* RTL format characters: RTL Classes. (line 77) +* RTL function-call insns: Calls. (line 6) +* RTL insn template: RTL Template. (line 6) +* RTL integers: RTL Objects. (line 6) +* RTL memory expressions: Regs and Memory. (line 6) +* RTL object types: RTL Objects. (line 6) +* RTL postdecrement: Incdec. (line 6) +* RTL postincrement: Incdec. (line 6) +* RTL predecrement: Incdec. (line 6) +* RTL preincrement: Incdec. (line 6) +* RTL register expressions: Regs and Memory. (line 6) +* RTL representation: RTL. (line 6) +* RTL side effect expressions: Side Effects. (line 6) +* RTL strings: RTL Objects. (line 6) +* RTL structure sharing assumptions: Sharing. (line 6) +* RTL subtraction: Arithmetic. (line 36) +* RTL subtraction with signed saturation: Arithmetic. (line 36) +* RTL subtraction with unsigned saturation: Arithmetic. (line 36) +* RTL sum: Arithmetic. (line 14) +* RTL vectors: RTL Objects. (line 6) +* RTL_CONST_CALL_P: Flags. (line 19) +* RTL_CONST_OR_PURE_CALL_P: Flags. (line 29) +* RTL_LOOPING_CONST_OR_PURE_CALL_P: Flags. (line 33) +* RTL_PURE_CALL_P: Flags. (line 24) +* RTX (See RTL): RTL Objects. (line 6) +* RTX codes, classes of: RTL Classes. (line 6) +* RTX_FRAME_RELATED_P: Flags. (line 125) +* run-time conventions: Interface. (line 6) +* run-time target specification: Run-time Target. (line 6) +* s in constraint: Simple Constraints. (line 102) +* same_type_p: Types. (line 88) +* SAmode: Machine Modes. (line 148) +* sat_fract: Conversions. (line 90) +* satfractMN2 instruction pattern: Standard Names. (line 856) +* satfractunsMN2 instruction pattern: Standard Names. (line 869) +* satisfies_constraint_: C Constraint Interface. + (line 47) +* SAVE_EXPR: Unary and Binary Expressions. + (line 6) +* save_stack_block instruction pattern: Standard Names. (line 1174) +* save_stack_function instruction pattern: Standard Names. (line 1174) +* save_stack_nonlocal instruction pattern: Standard Names. (line 1174) +* SBSS_SECTION_ASM_OP: Sections. (line 77) +* Scalar evolutions: Scalar evolutions. (line 6) +* scalars, returned as values: Scalar Return. (line 6) +* SCHED_GROUP_P: Flags. (line 166) +* SCmode: Machine Modes. (line 197) +* scratch: Regs and Memory. (line 298) +* scratch operands: Regs and Memory. (line 298) +* scratch, RTL sharing: Sharing. (line 35) +* scratch_operand: Machine-Independent Predicates. + (line 50) +* SDATA_SECTION_ASM_OP: Sections. (line 58) +* SDB_ALLOW_FORWARD_REFERENCES: SDB and DWARF. (line 119) +* SDB_ALLOW_UNKNOWN_REFERENCES: SDB and DWARF. (line 114) +* SDB_DEBUGGING_INFO: SDB and DWARF. (line 9) +* SDB_DELIM: SDB and DWARF. (line 107) +* SDB_OUTPUT_SOURCE_LINE: SDB and DWARF. (line 124) +* SDmode: Machine Modes. (line 85) +* sdot_prodM instruction pattern: Standard Names. (line 291) +* search options: Including Patterns. (line 44) +* SECONDARY_INPUT_RELOAD_CLASS: Register Classes. (line 394) +* SECONDARY_MEMORY_NEEDED: Register Classes. (line 450) +* SECONDARY_MEMORY_NEEDED_MODE: Register Classes. (line 469) +* SECONDARY_MEMORY_NEEDED_RTX: Register Classes. (line 460) +* SECONDARY_OUTPUT_RELOAD_CLASS: Register Classes. (line 395) +* SECONDARY_RELOAD_CLASS: Register Classes. (line 393) +* SELECT_CC_MODE: MODE_CC Condition Codes. + (line 7) +* sequence: Side Effects. (line 254) +* Sequence iterators: Sequence iterators. (line 6) +* set: Side Effects. (line 15) +* set and /f: Flags. (line 125) +* SET_ASM_OP: Label Output. (line 418) +* set_attr: Tagging Insns. (line 31) +* set_attr_alternative: Tagging Insns. (line 49) +* set_bb_seq: GIMPLE sequences. (line 76) +* SET_BY_PIECES_P: Costs. (line 206) +* SET_DEST: Side Effects. (line 69) +* SET_IS_RETURN_P: Flags. (line 175) +* SET_LABEL_KIND: Insns. (line 140) +* set_optab_libfunc: Library Calls. (line 15) +* SET_RATIO: Costs. (line 194) +* SET_SRC: Side Effects. (line 69) +* SET_TYPE_STRUCTURAL_EQUALITY: Types. (line 83) +* setmemM instruction pattern: Standard Names. (line 724) +* SETUP_FRAME_ADDRESSES: Frame Layout. (line 102) +* SF_SIZE: Type Layout. (line 128) +* SFmode: Machine Modes. (line 66) +* sharing of RTL components: Sharing. (line 6) +* shift: Arithmetic. (line 173) +* SHIFT_COUNT_TRUNCATED: Misc. (line 127) +* SHLIB_SUFFIX: Macros for Initialization. + (line 135) +* SHORT_ACCUM_TYPE_SIZE: Type Layout. (line 83) +* SHORT_FRACT_TYPE_SIZE: Type Layout. (line 63) +* SHORT_IMMEDIATES_SIGN_EXTEND: Misc. (line 96) +* SHORT_TYPE_SIZE: Type Layout. (line 16) +* sibcall_epilogue instruction pattern: Standard Names. (line 1371) +* sibling call: Edges. (line 122) +* SIBLING_CALL_P: Flags. (line 179) +* SIG_ATOMIC_TYPE: Type Layout. (line 234) +* sign_extend: Conversions. (line 23) +* sign_extract: Bit-Fields. (line 8) +* sign_extract, canonicalization of: Insn Canonicalizations. + (line 88) +* signed division: Arithmetic. (line 116) +* signed division with signed saturation: Arithmetic. (line 116) +* signed maximum: Arithmetic. (line 141) +* signed minimum: Arithmetic. (line 141) +* SImode: Machine Modes. (line 37) +* simple constraints: Simple Constraints. (line 6) +* sincos math function, implicit usage: Library Calls. (line 70) +* sinM2 instruction pattern: Standard Names. (line 516) +* SIZE_ASM_OP: Label Output. (line 35) +* SIZE_TYPE: Type Layout. (line 167) +* skip: GTY Options. (line 72) +* SLOW_BYTE_ACCESS: Costs. (line 118) +* SLOW_UNALIGNED_ACCESS: Costs. (line 133) +* smax: Arithmetic. (line 141) +* smin: Arithmetic. (line 141) +* sms, swing, software pipelining: RTL passes. (line 131) +* smulM3_highpart instruction pattern: Standard Names. (line 383) +* soft float library: Soft float library routines. + (line 6) +* special: GTY Options. (line 249) +* special predicates: Predicates. (line 31) +* SPECS: Target Fragment. (line 108) +* speed of instructions: Costs. (line 6) +* split_block: Maintaining the CFG. + (line 110) +* splitting instructions: Insn Splitting. (line 6) +* SQmode: Machine Modes. (line 111) +* sqrt: Arithmetic. (line 207) +* sqrtM2 instruction pattern: Standard Names. (line 482) +* square root: Arithmetic. (line 207) +* ss_abs: Arithmetic. (line 200) +* ss_ashift: Arithmetic. (line 173) +* ss_div: Arithmetic. (line 116) +* ss_minus: Arithmetic. (line 36) +* ss_mult: Arithmetic. (line 92) +* ss_neg: Arithmetic. (line 81) +* ss_plus: Arithmetic. (line 14) +* ss_truncate: Conversions. (line 43) +* SSA: SSA. (line 6) +* SSA_NAME_DEF_STMT: SSA. (line 221) +* SSA_NAME_VERSION: SSA. (line 226) +* ssaddM3 instruction pattern: Standard Names. (line 222) +* ssashlM3 instruction pattern: Standard Names. (line 458) +* ssdivM3 instruction pattern: Standard Names. (line 222) +* ssmaddMN4 instruction pattern: Standard Names. (line 406) +* ssmsubMN4 instruction pattern: Standard Names. (line 430) +* ssmulM3 instruction pattern: Standard Names. (line 222) +* ssnegM2 instruction pattern: Standard Names. (line 476) +* sssubM3 instruction pattern: Standard Names. (line 222) +* ssum_widenM3 instruction pattern: Standard Names. (line 301) +* stack arguments: Stack Arguments. (line 6) +* stack frame layout: Frame Layout. (line 6) +* stack smashing protection: Stack Smashing Protection. + (line 6) +* STACK_ALIGNMENT_NEEDED: Frame Layout. (line 48) +* STACK_BOUNDARY: Storage Layout. (line 138) +* STACK_CHECK_BUILTIN: Stack Checking. (line 32) +* STACK_CHECK_FIXED_FRAME_SIZE: Stack Checking. (line 83) +* STACK_CHECK_MAX_FRAME_SIZE: Stack Checking. (line 74) +* STACK_CHECK_MAX_VAR_SIZE: Stack Checking. (line 90) +* STACK_CHECK_MOVING_SP: Stack Checking. (line 54) +* STACK_CHECK_PROBE_INTERVAL_EXP: Stack Checking. (line 46) +* STACK_CHECK_PROTECT: Stack Checking. (line 63) +* STACK_CHECK_STATIC_BUILTIN: Stack Checking. (line 39) +* STACK_DYNAMIC_OFFSET: Frame Layout. (line 75) +* STACK_DYNAMIC_OFFSET and virtual registers: Regs and Memory. + (line 83) +* STACK_GROWS_DOWNWARD: Frame Layout. (line 9) +* STACK_PARMS_IN_REG_PARM_AREA: Stack Arguments. (line 84) +* STACK_POINTER_OFFSET: Frame Layout. (line 58) +* STACK_POINTER_OFFSET and virtual registers: Regs and Memory. + (line 93) +* STACK_POINTER_REGNUM: Frame Registers. (line 9) +* STACK_POINTER_REGNUM and virtual registers: Regs and Memory. + (line 83) +* stack_pointer_rtx: Frame Registers. (line 104) +* stack_protect_set instruction pattern: Standard Names. (line 1542) +* stack_protect_test instruction pattern: Standard Names. (line 1552) +* STACK_PUSH_CODE: Frame Layout. (line 17) +* STACK_REG_COVER_CLASS: Stack Registers. (line 23) +* STACK_REGS: Stack Registers. (line 20) +* STACK_SAVEAREA_MODE: Storage Layout. (line 424) +* STACK_SIZE_MODE: Storage Layout. (line 436) +* STACK_SLOT_ALIGNMENT: Storage Layout. (line 256) +* standard pattern names: Standard Names. (line 6) +* STANDARD_INCLUDE_COMPONENT: Driver. (line 339) +* STANDARD_INCLUDE_DIR: Driver. (line 331) +* STANDARD_STARTFILE_PREFIX: Driver. (line 275) +* STANDARD_STARTFILE_PREFIX_1: Driver. (line 282) +* STANDARD_STARTFILE_PREFIX_2: Driver. (line 289) +* STARTFILE_SPEC: Driver. (line 148) +* STARTING_FRAME_OFFSET: Frame Layout. (line 39) +* STARTING_FRAME_OFFSET and virtual registers: Regs and Memory. + (line 74) +* Statement and operand traversals: Statement and operand traversals. + (line 6) +* Statement Sequences: Statement Sequences. + (line 6) +* statements <1>: Statements for C++. (line 6) +* statements: Function Properties. + (line 6) +* Statements: Statements. (line 6) +* Static profile estimation: Profile information. + (line 24) +* static single assignment: SSA. (line 6) +* STATIC_CHAIN_INCOMING_REGNUM: Frame Registers. (line 78) +* STATIC_CHAIN_REGNUM: Frame Registers. (line 77) +* stdarg.h and register arguments: Register Arguments. (line 47) +* STDC_0_IN_SYSTEM_HEADERS: Misc. (line 365) +* STMT_EXPR: Unary and Binary Expressions. + (line 6) +* STMT_IS_FULL_EXPR_P: Statements for C++. (line 22) +* storage layout: Storage Layout. (line 6) +* STORE_BY_PIECES_P: Costs. (line 213) +* STORE_FLAG_VALUE: Misc. (line 216) +* store_multiple instruction pattern: Standard Names. (line 160) +* strcpy: Storage Layout. (line 223) +* STRICT_ALIGNMENT: Storage Layout. (line 306) +* strict_low_part: RTL Declarations. (line 9) +* strict_memory_address_p: Addressing Modes. (line 185) +* STRING_CST: Constant expressions. + (line 6) +* STRING_POOL_ADDRESS_P: Flags. (line 183) +* strlenM instruction pattern: Standard Names. (line 791) +* structure value address: Aggregate Return. (line 6) +* STRUCTURE_SIZE_BOUNDARY: Storage Layout. (line 298) +* structures, returning: Interface. (line 10) +* subM3 instruction pattern: Standard Names. (line 222) +* SUBOBJECT: Statements for C++. (line 6) +* SUBOBJECT_CLEANUP: Statements for C++. (line 6) +* subreg: Regs and Memory. (line 97) +* subreg and /s: Flags. (line 205) +* subreg and /u: Flags. (line 198) +* subreg and /u and /v: Flags. (line 188) +* subreg, in strict_low_part: RTL Declarations. (line 9) +* SUBREG_BYTE: Regs and Memory. (line 289) +* SUBREG_PROMOTED_UNSIGNED_P: Flags. (line 188) +* SUBREG_PROMOTED_UNSIGNED_SET: Flags. (line 198) +* SUBREG_PROMOTED_VAR_P: Flags. (line 205) +* SUBREG_REG: Regs and Memory. (line 289) +* SUCCESS_EXIT_CODE: Host Misc. (line 12) +* SUPPORTS_INIT_PRIORITY: Macros for Initialization. + (line 58) +* SUPPORTS_ONE_ONLY: Label Output. (line 247) +* SUPPORTS_WEAK: Label Output. (line 221) +* SWITCH_BODY: Statements for C++. (line 6) +* SWITCH_COND: Statements for C++. (line 6) +* SWITCH_STMT: Statements for C++. (line 6) +* SWITCHABLE_TARGET: Run-time Target. (line 176) +* SYMBOL_FLAG_ANCHOR: Special Accessors. (line 110) +* SYMBOL_FLAG_EXTERNAL: Special Accessors. (line 92) +* SYMBOL_FLAG_FUNCTION: Special Accessors. (line 85) +* SYMBOL_FLAG_HAS_BLOCK_INFO: Special Accessors. (line 106) +* SYMBOL_FLAG_LOCAL: Special Accessors. (line 88) +* SYMBOL_FLAG_SMALL: Special Accessors. (line 97) +* SYMBOL_FLAG_TLS_SHIFT: Special Accessors. (line 101) +* symbol_ref: Constants. (line 76) +* symbol_ref and /f: Flags. (line 183) +* symbol_ref and /i: Flags. (line 220) +* symbol_ref and /u: Flags. (line 10) +* symbol_ref and /v: Flags. (line 224) +* symbol_ref, RTL sharing: Sharing. (line 20) +* SYMBOL_REF_ANCHOR_P: Special Accessors. (line 110) +* SYMBOL_REF_BLOCK: Special Accessors. (line 123) +* SYMBOL_REF_BLOCK_OFFSET: Special Accessors. (line 128) +* SYMBOL_REF_CONSTANT: Special Accessors. (line 71) +* SYMBOL_REF_DATA: Special Accessors. (line 75) +* SYMBOL_REF_DECL: Special Accessors. (line 59) +* SYMBOL_REF_EXTERNAL_P: Special Accessors. (line 92) +* SYMBOL_REF_FLAG: Flags. (line 224) +* SYMBOL_REF_FLAG, in TARGET_ENCODE_SECTION_INFO: Sections. (line 269) +* SYMBOL_REF_FLAGS: Special Accessors. (line 79) +* SYMBOL_REF_FUNCTION_P: Special Accessors. (line 85) +* SYMBOL_REF_HAS_BLOCK_INFO_P: Special Accessors. (line 106) +* SYMBOL_REF_LOCAL_P: Special Accessors. (line 88) +* SYMBOL_REF_SMALL_P: Special Accessors. (line 97) +* SYMBOL_REF_TLS_MODEL: Special Accessors. (line 101) +* SYMBOL_REF_USED: Flags. (line 215) +* SYMBOL_REF_WEAK: Flags. (line 220) +* symbolic label: Sharing. (line 20) +* sync_addMODE instruction pattern: Standard Names. (line 1458) +* sync_andMODE instruction pattern: Standard Names. (line 1458) +* sync_compare_and_swapMODE instruction pattern: Standard Names. + (line 1428) +* sync_iorMODE instruction pattern: Standard Names. (line 1458) +* sync_lock_releaseMODE instruction pattern: Standard Names. (line 1523) +* sync_lock_test_and_setMODE instruction pattern: Standard Names. + (line 1497) +* sync_nandMODE instruction pattern: Standard Names. (line 1458) +* sync_new_addMODE instruction pattern: Standard Names. (line 1490) +* sync_new_andMODE instruction pattern: Standard Names. (line 1490) +* sync_new_iorMODE instruction pattern: Standard Names. (line 1490) +* sync_new_nandMODE instruction pattern: Standard Names. (line 1490) +* sync_new_subMODE instruction pattern: Standard Names. (line 1490) +* sync_new_xorMODE instruction pattern: Standard Names. (line 1490) +* sync_old_addMODE instruction pattern: Standard Names. (line 1473) +* sync_old_andMODE instruction pattern: Standard Names. (line 1473) +* sync_old_iorMODE instruction pattern: Standard Names. (line 1473) +* sync_old_nandMODE instruction pattern: Standard Names. (line 1473) +* sync_old_subMODE instruction pattern: Standard Names. (line 1473) +* sync_old_xorMODE instruction pattern: Standard Names. (line 1473) +* sync_subMODE instruction pattern: Standard Names. (line 1458) +* sync_xorMODE instruction pattern: Standard Names. (line 1458) +* SYSROOT_HEADERS_SUFFIX_SPEC: Driver. (line 177) +* SYSROOT_SUFFIX_SPEC: Driver. (line 172) +* SYSTEM_INCLUDE_DIR: Driver. (line 322) +* t-TARGET: Target Fragment. (line 6) +* table jump: Basic Blocks. (line 57) +* tablejump instruction pattern: Standard Names. (line 1102) +* tag: GTY Options. (line 77) +* tagging insns: Tagging Insns. (line 6) +* tail calls: Tail Calls. (line 6) +* TAmode: Machine Modes. (line 156) +* target attributes: Target Attributes. (line 6) +* target description macros: Target Macros. (line 6) +* target functions: Target Structure. (line 6) +* target hooks: Target Structure. (line 6) +* target makefile fragment: Target Fragment. (line 6) +* target specifications: Run-time Target. (line 6) +* TARGET_ADDR_SPACE_ADDRESS_MODE: Named Address Spaces. + (line 45) +* TARGET_ADDR_SPACE_CONVERT: Named Address Spaces. + (line 88) +* TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P: Named Address Spaces. + (line 63) +* TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS: Named Address Spaces. + (line 72) +* TARGET_ADDR_SPACE_POINTER_MODE: Named Address Spaces. + (line 38) +* TARGET_ADDR_SPACE_SUBSET_P: Named Address Spaces. + (line 79) +* TARGET_ADDR_SPACE_VALID_POINTER_MODE: Named Address Spaces. + (line 52) +* TARGET_ADDRESS_COST: Costs. (line 297) +* TARGET_ALIGN_ANON_BITFIELD: Storage Layout. (line 383) +* TARGET_ALLOCATE_INITIAL_VALUE: Misc. (line 697) +* TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS: Misc. (line 977) +* TARGET_ARG_PARTIAL_BYTES: Register Arguments. (line 83) +* TARGET_ARM_EABI_UNWINDER: Exception Region Output. + (line 122) +* TARGET_ASM_ALIGNED_DI_OP: Data Output. (line 10) +* TARGET_ASM_ALIGNED_HI_OP: Data Output. (line 8) +* TARGET_ASM_ALIGNED_SI_OP: Data Output. (line 9) +* TARGET_ASM_ALIGNED_TI_OP: Data Output. (line 11) +* TARGET_ASM_ASSEMBLE_VISIBILITY: Label Output. (line 259) +* TARGET_ASM_BYTE_OP: Data Output. (line 7) +* TARGET_ASM_CAN_OUTPUT_MI_THUNK: Function Entry. (line 237) +* TARGET_ASM_CLOSE_PAREN: Data Output. (line 142) +* TARGET_ASM_CODE_END: File Framework. (line 59) +* TARGET_ASM_CONSTRUCTOR: Macros for Initialization. + (line 69) +* TARGET_ASM_DECLARE_CONSTANT_NAME: Label Output. (line 142) +* TARGET_ASM_DESTRUCTOR: Macros for Initialization. + (line 83) +* TARGET_ASM_EMIT_EXCEPT_PERSONALITY: Dispatch Tables. (line 82) +* TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL: Dispatch Tables. (line 74) +* TARGET_ASM_EMIT_UNWIND_LABEL: Dispatch Tables. (line 63) +* TARGET_ASM_EXTERNAL_LIBCALL: Label Output. (line 294) +* TARGET_ASM_FILE_END: File Framework. (line 37) +* TARGET_ASM_FILE_START: File Framework. (line 9) +* TARGET_ASM_FILE_START_APP_OFF: File Framework. (line 17) +* TARGET_ASM_FILE_START_FILE_DIRECTIVE: File Framework. (line 31) +* TARGET_ASM_FINAL_POSTSCAN_INSN: Instruction Output. (line 84) +* TARGET_ASM_FUNCTION_BEGIN_EPILOGUE: Function Entry. (line 61) +* TARGET_ASM_FUNCTION_END_PROLOGUE: Function Entry. (line 55) +* TARGET_ASM_FUNCTION_EPILOGUE: Function Entry. (line 68) +* TARGET_ASM_FUNCTION_PROLOGUE: Function Entry. (line 11) +* TARGET_ASM_FUNCTION_RODATA_SECTION: Sections. (line 216) +* TARGET_ASM_FUNCTION_SECTION: File Framework. (line 123) +* TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS: File Framework. + (line 133) +* TARGET_ASM_GLOBALIZE_DECL_NAME: Label Output. (line 187) +* TARGET_ASM_GLOBALIZE_LABEL: Label Output. (line 178) +* TARGET_ASM_INIT_SECTIONS: Sections. (line 161) +* TARGET_ASM_INTEGER: Data Output. (line 27) +* TARGET_ASM_INTERNAL_LABEL: Label Output. (line 338) +* TARGET_ASM_JUMP_ALIGN_MAX_SKIP: Alignment Output. (line 22) +* TARGET_ASM_LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP: Alignment Output. + (line 36) +* TARGET_ASM_LABEL_ALIGN_MAX_SKIP: Alignment Output. (line 69) +* TARGET_ASM_LOOP_ALIGN_MAX_SKIP: Alignment Output. (line 54) +* TARGET_ASM_LTO_END: File Framework. (line 54) +* TARGET_ASM_LTO_START: File Framework. (line 49) +* TARGET_ASM_MARK_DECL_PRESERVED: Label Output. (line 301) +* TARGET_ASM_NAMED_SECTION: File Framework. (line 115) +* TARGET_ASM_OPEN_PAREN: Data Output. (line 141) +* TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA: Data Output. (line 40) +* TARGET_ASM_OUTPUT_ANCHOR: Anchored Addresses. (line 44) +* TARGET_ASM_OUTPUT_DWARF_DTPREL: SDB and DWARF. (line 96) +* TARGET_ASM_OUTPUT_MI_THUNK: Function Entry. (line 195) +* TARGET_ASM_OUTPUT_SOURCE_FILENAME: File Framework. (line 94) +* TARGET_ASM_RECORD_GCC_SWITCHES: File Framework. (line 164) +* TARGET_ASM_RECORD_GCC_SWITCHES_SECTION: File Framework. (line 208) +* TARGET_ASM_RELOC_RW_MASK: Sections. (line 170) +* TARGET_ASM_SELECT_RTX_SECTION: Sections. (line 224) +* TARGET_ASM_SELECT_SECTION: Sections. (line 182) +* TARGET_ASM_TRAMPOLINE_TEMPLATE: Trampolines. (line 29) +* TARGET_ASM_TTYPE: Exception Region Output. + (line 116) +* TARGET_ASM_UNALIGNED_DI_OP: Data Output. (line 14) +* TARGET_ASM_UNALIGNED_HI_OP: Data Output. (line 12) +* TARGET_ASM_UNALIGNED_SI_OP: Data Output. (line 13) +* TARGET_ASM_UNALIGNED_TI_OP: Data Output. (line 15) +* TARGET_ASM_UNIQUE_SECTION: Sections. (line 203) +* TARGET_ASM_UNWIND_EMIT: Dispatch Tables. (line 88) +* TARGET_ASM_UNWIND_EMIT_BEFORE_INSN: Dispatch Tables. (line 93) +* TARGET_ATTRIBUTE_TABLE: Target Attributes. (line 11) +* TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P: Target Attributes. (line 19) +* TARGET_BINDS_LOCAL_P: Sections. (line 301) +* TARGET_BRANCH_TARGET_REGISTER_CALLEE_SAVED: Misc. (line 794) +* TARGET_BRANCH_TARGET_REGISTER_CLASS: Misc. (line 786) +* TARGET_BUILD_BUILTIN_VA_LIST: Register Arguments. (line 264) +* TARGET_BUILTIN_DECL: Misc. (line 620) +* TARGET_BUILTIN_RECIPROCAL: Addressing Modes. (line 265) +* TARGET_BUILTIN_SETJMP_FRAME_VALUE: Frame Layout. (line 109) +* TARGET_C99_FUNCTIONS: Library Calls. (line 63) +* TARGET_CALLEE_COPIES: Register Arguments. (line 115) +* TARGET_CAN_ELIMINATE: Elimination. (line 75) +* TARGET_CAN_INLINE_P: Target Attributes. (line 150) +* TARGET_CANNOT_FORCE_CONST_MEM: Addressing Modes. (line 246) +* TARGET_CANNOT_MODIFY_JUMPS_P: Misc. (line 773) +* TARGET_CANONICAL_VA_LIST_TYPE: Register Arguments. (line 285) +* TARGET_CASE_VALUES_THRESHOLD: Misc. (line 47) +* TARGET_CC_MODES_COMPATIBLE: MODE_CC Condition Codes. + (line 116) +* TARGET_CHECK_PCH_TARGET_FLAGS: PCH Target. (line 28) +* TARGET_CHECK_STRING_OBJECT_FORMAT_ARG: Run-time Target. (line 113) +* TARGET_CLASS_LIKELY_SPILLED_P: Register Classes. (line 492) +* TARGET_COMMUTATIVE_P: Misc. (line 690) +* TARGET_COMP_TYPE_ATTRIBUTES: Target Attributes. (line 27) +* TARGET_CONDITIONAL_REGISTER_USAGE: Register Basics. (line 60) +* TARGET_CONST_ANCHOR: Misc. (line 988) +* TARGET_CONVERT_TO_TYPE: Misc. (line 941) +* TARGET_CPU_CPP_BUILTINS: Run-time Target. (line 9) +* TARGET_CXX_ADJUST_CLASS_AT_DEFINITION: C++ ABI. (line 87) +* TARGET_CXX_CDTOR_RETURNS_THIS: C++ ABI. (line 38) +* TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT: C++ ABI. (line 62) +* TARGET_CXX_COOKIE_HAS_SIZE: C++ ABI. (line 25) +* TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY: C++ ABI. (line 54) +* TARGET_CXX_GET_COOKIE_SIZE: C++ ABI. (line 18) +* TARGET_CXX_GUARD_MASK_BIT: C++ ABI. (line 12) +* TARGET_CXX_GUARD_TYPE: C++ ABI. (line 7) +* TARGET_CXX_IMPORT_EXPORT_CLASS: C++ ABI. (line 30) +* TARGET_CXX_KEY_METHOD_MAY_BE_INLINE: C++ ABI. (line 43) +* TARGET_CXX_LIBRARY_RTTI_COMDAT: C++ ABI. (line 69) +* TARGET_CXX_USE_AEABI_ATEXIT: C++ ABI. (line 74) +* TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT: C++ ABI. (line 80) +* TARGET_DEBUG_UNWIND_INFO: SDB and DWARF. (line 37) +* TARGET_DECIMAL_FLOAT_SUPPORTED_P: Storage Layout. (line 508) +* TARGET_DECLSPEC: Target Attributes. (line 73) +* TARGET_DEFAULT_PACK_STRUCT: Misc. (line 445) +* TARGET_DEFAULT_SHORT_ENUMS: Type Layout. (line 159) +* TARGET_DEFAULT_TARGET_FLAGS: Run-time Target. (line 56) +* TARGET_DEFERRED_OUTPUT_DEFS: Label Output. (line 422) +* TARGET_DELAY_SCHED2: SDB and DWARF. (line 61) +* TARGET_DELAY_VARTRACK: SDB and DWARF. (line 65) +* TARGET_DELEGITIMIZE_ADDRESS: Addressing Modes. (line 237) +* TARGET_DLLIMPORT_DECL_ATTRIBUTES: Target Attributes. (line 55) +* TARGET_DWARF_CALLING_CONVENTION: SDB and DWARF. (line 18) +* TARGET_DWARF_HANDLE_FRAME_UNSPEC: Frame Layout. (line 172) +* TARGET_DWARF_REGISTER_SPAN: Exception Region Output. + (line 99) +* TARGET_EDOM: Library Calls. (line 45) +* TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS: Emulated TLS. (line 68) +* TARGET_EMUTLS_GET_ADDRESS: Emulated TLS. (line 19) +* TARGET_EMUTLS_REGISTER_COMMON: Emulated TLS. (line 24) +* TARGET_EMUTLS_TMPL_PREFIX: Emulated TLS. (line 45) +* TARGET_EMUTLS_TMPL_SECTION: Emulated TLS. (line 36) +* TARGET_EMUTLS_VAR_ALIGN_FIXED: Emulated TLS. (line 63) +* TARGET_EMUTLS_VAR_FIELDS: Emulated TLS. (line 49) +* TARGET_EMUTLS_VAR_INIT: Emulated TLS. (line 57) +* TARGET_EMUTLS_VAR_PREFIX: Emulated TLS. (line 41) +* TARGET_EMUTLS_VAR_SECTION: Emulated TLS. (line 31) +* TARGET_ENCODE_SECTION_INFO: Sections. (line 245) +* TARGET_ENCODE_SECTION_INFO and address validation: Addressing Modes. + (line 83) +* TARGET_ENCODE_SECTION_INFO usage: Instruction Output. (line 128) +* TARGET_ENUM_VA_LIST_P: Register Arguments. (line 269) +* TARGET_EXCEPT_UNWIND_INFO: Exception Region Output. + (line 48) +* TARGET_EXECUTABLE_SUFFIX: Misc. (line 747) +* TARGET_EXPAND_BUILTIN: Misc. (line 630) +* TARGET_EXPAND_BUILTIN_SAVEREGS: Varargs. (line 67) +* TARGET_EXPAND_TO_RTL_HOOK: Storage Layout. (line 514) +* TARGET_EXPR: Unary and Binary Expressions. + (line 6) +* TARGET_EXTRA_INCLUDES: Misc. (line 834) +* TARGET_EXTRA_LIVE_ON_ENTRY: Tail Calls. (line 21) +* TARGET_EXTRA_PRE_INCLUDES: Misc. (line 841) +* TARGET_FIXED_CONDITION_CODE_REGS: MODE_CC Condition Codes. + (line 101) +* TARGET_FIXED_POINT_SUPPORTED_P: Storage Layout. (line 511) +* target_flags: Run-time Target. (line 52) +* TARGET_FLAGS_REGNUM: Register Arguments. (line 361) +* TARGET_FLT_EVAL_METHOD: Type Layout. (line 140) +* TARGET_FN_ABI_VA_LIST: Register Arguments. (line 280) +* TARGET_FOLD_BUILTIN: Misc. (line 651) +* TARGET_FORMAT_TYPES: Misc. (line 861) +* TARGET_FRAME_POINTER_REQUIRED: Elimination. (line 9) +* TARGET_FUNCTION_ARG_BOUNDARY: Register Arguments. (line 239) +* TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P: Target Attributes. (line 95) +* TARGET_FUNCTION_OK_FOR_SIBCALL: Tail Calls. (line 8) +* TARGET_FUNCTION_VALUE: Scalar Return. (line 11) +* TARGET_FUNCTION_VALUE_REGNO_P: Scalar Return. (line 97) +* TARGET_GET_DRAP_RTX: Misc. (line 971) +* TARGET_GET_PCH_VALIDITY: PCH Target. (line 7) +* TARGET_GET_RAW_ARG_MODE: Aggregate Return. (line 83) +* TARGET_GET_RAW_RESULT_MODE: Aggregate Return. (line 78) +* TARGET_GIMPLIFY_VA_ARG_EXPR: Register Arguments. (line 291) +* TARGET_HANDLE_C_OPTION: Run-time Target. (line 78) +* TARGET_HANDLE_OPTION: Run-time Target. (line 61) +* TARGET_HANDLE_PRAGMA_EXTERN_PREFIX: Misc. (line 442) +* TARGET_HARD_REGNO_SCRATCH_OK: Values in Registers. + (line 144) +* TARGET_HAS_SINCOS: Library Calls. (line 71) +* TARGET_HAVE_CONDITIONAL_EXECUTION: Misc. (line 808) +* TARGET_HAVE_CTORS_DTORS: Macros for Initialization. + (line 64) +* TARGET_HAVE_NAMED_SECTIONS: File Framework. (line 140) +* TARGET_HAVE_SRODATA_SECTION: Sections. (line 290) +* TARGET_HAVE_SWITCHABLE_BSS_SECTIONS: File Framework. (line 145) +* TARGET_HAVE_TLS: Sections. (line 310) +* TARGET_HELP: Run-time Target. (line 170) +* TARGET_IN_SMALL_DATA_P: Sections. (line 286) +* TARGET_INIT_BUILTINS: Misc. (line 602) +* TARGET_INIT_DWARF_REG_SIZES_EXTRA: Exception Region Output. + (line 108) +* TARGET_INIT_LIBFUNCS: Library Calls. (line 16) +* TARGET_INSERT_ATTRIBUTES: Target Attributes. (line 82) +* TARGET_INSTANTIATE_DECLS: Storage Layout. (line 522) +* TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN: Misc. (line 895) +* TARGET_INVALID_BINARY_OP: Misc. (line 914) +* TARGET_INVALID_CONVERSION: Misc. (line 901) +* TARGET_INVALID_PARAMETER_TYPE: Misc. (line 920) +* TARGET_INVALID_RETURN_TYPE: Misc. (line 927) +* TARGET_INVALID_UNARY_OP: Misc. (line 907) +* TARGET_INVALID_WITHIN_DOLOOP: Misc. (line 670) +* TARGET_IRA_COVER_CLASSES: Register Classes. (line 537) +* TARGET_LEGITIMATE_ADDRESS_P: Addressing Modes. (line 50) +* TARGET_LEGITIMIZE_ADDRESS: Addressing Modes. (line 132) +* TARGET_LIB_INT_CMP_BIASED: Library Calls. (line 35) +* TARGET_LIBCALL_VALUE: Scalar Return. (line 66) +* TARGET_LIBGCC_CMP_RETURN_MODE: Storage Layout. (line 445) +* TARGET_LIBGCC_SDATA_SECTION: Sections. (line 133) +* TARGET_LIBGCC_SHIFT_COUNT_MODE: Storage Layout. (line 451) +* TARGET_LOOP_UNROLL_ADJUST: Misc. (line 815) +* TARGET_MACHINE_DEPENDENT_REORG: Misc. (line 587) +* TARGET_MANGLE_ASSEMBLER_NAME: Label Output. (line 313) +* TARGET_MANGLE_DECL_ASSEMBLER_NAME: Sections. (line 235) +* TARGET_MANGLE_TYPE: Storage Layout. (line 526) +* TARGET_MAX_ANCHOR_OFFSET: Anchored Addresses. (line 39) +* TARGET_MD_ASM_CLOBBERS: Misc. (line 503) +* TARGET_MEM_CONSTRAINT: Addressing Modes. (line 109) +* TARGET_MEM_REF: Storage References. (line 6) +* TARGET_MEMORY_MOVE_COST: Costs. (line 81) +* TARGET_MERGE_DECL_ATTRIBUTES: Target Attributes. (line 47) +* TARGET_MERGE_TYPE_ATTRIBUTES: Target Attributes. (line 39) +* TARGET_MIN_ANCHOR_OFFSET: Anchored Addresses. (line 33) +* TARGET_MIN_DIVISIONS_FOR_RECIP_MUL: Misc. (line 106) +* TARGET_MODE_DEPENDENT_ADDRESS_P: Addressing Modes. (line 196) +* TARGET_MODE_REP_EXTENDED: Misc. (line 191) +* TARGET_MS_BITFIELD_LAYOUT_P: Storage Layout. (line 481) +* TARGET_MUST_PASS_IN_STACK: Register Arguments. (line 62) +* TARGET_MUST_PASS_IN_STACK, and FUNCTION_ARG: Register Arguments. + (line 52) +* TARGET_MVERSION_FUNCTION: Misc. (line 660) +* TARGET_N_FORMAT_TYPES: Misc. (line 866) +* TARGET_NARROW_VOLATILE_BITFIELD: Storage Layout. (line 389) +* TARGET_OBJC_CONSTRUCT_STRING_OBJECT: Run-time Target. (line 92) +* TARGET_OBJECT_SUFFIX: Misc. (line 742) +* TARGET_OBJFMT_CPP_BUILTINS: Run-time Target. (line 46) +* TARGET_OPTF: Misc. (line 848) +* TARGET_OPTION_DEFAULT_PARAMS: Run-time Target. (line 166) +* TARGET_OPTION_INIT_STRUCT: Run-time Target. (line 163) +* TARGET_OPTION_OPTIMIZATION_TABLE: Run-time Target. (line 149) +* TARGET_OPTION_OVERRIDE: Target Attributes. (line 137) +* TARGET_OPTION_PRAGMA_PARSE: Target Attributes. (line 131) +* TARGET_OPTION_PRINT: Target Attributes. (line 125) +* TARGET_OPTION_RESTORE: Target Attributes. (line 119) +* TARGET_OPTION_SAVE: Target Attributes. (line 113) +* TARGET_OPTION_VALID_ATTRIBUTE_P: Target Attributes. (line 102) +* TARGET_OS_CPP_BUILTINS: Run-time Target. (line 42) +* TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE: Run-time Target. (line 132) +* TARGET_OVERRIDES_FORMAT_ATTRIBUTES: Misc. (line 870) +* TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT: Misc. (line 876) +* TARGET_OVERRIDES_FORMAT_INIT: Misc. (line 880) +* TARGET_PASS_BY_REFERENCE: Register Arguments. (line 103) +* TARGET_PCH_VALID_P: PCH Target. (line 13) +* TARGET_POSIX_IO: Misc. (line 527) +* TARGET_PREFERRED_OUTPUT_RELOAD_CLASS: Register Classes. (line 287) +* TARGET_PREFERRED_RELOAD_CLASS: Register Classes. (line 208) +* TARGET_PREFERRED_RENAME_CLASS: Register Classes. (line 196) +* TARGET_PRETEND_OUTGOING_VARARGS_NAMED: Varargs. (line 128) +* TARGET_PROFILE_BEFORE_PROLOGUE: Sections. (line 294) +* TARGET_PROMOTE_FUNCTION_MODE: Storage Layout. (line 112) +* TARGET_PROMOTE_PROTOTYPES: Stack Arguments. (line 11) +* TARGET_PROMOTED_TYPE: Misc. (line 933) +* TARGET_PTRMEMFUNC_VBIT_LOCATION: Type Layout. (line 277) +* TARGET_REF_MAY_ALIAS_ERRNO: Register Arguments. (line 302) +* TARGET_REGISTER_MOVE_COST: Costs. (line 33) +* TARGET_RELAXED_ORDERING: Misc. (line 885) +* TARGET_RESOLVE_OVERLOADED_BUILTIN: Misc. (line 640) +* TARGET_RETURN_IN_MEMORY: Aggregate Return. (line 17) +* TARGET_RETURN_IN_MSB: Scalar Return. (line 117) +* TARGET_RETURN_POPS_ARGS: Stack Arguments. (line 94) +* TARGET_RTX_COSTS: Costs. (line 271) +* TARGET_SCALAR_MODE_SUPPORTED_P: Register Arguments. (line 310) +* TARGET_SCHED_ADJUST_COST: Scheduling. (line 37) +* TARGET_SCHED_ADJUST_PRIORITY: Scheduling. (line 52) +* TARGET_SCHED_ALLOC_SCHED_CONTEXT: Scheduling. (line 274) +* TARGET_SCHED_CLEAR_SCHED_CONTEXT: Scheduling. (line 289) +* TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK: Scheduling. (line 89) +* TARGET_SCHED_DFA_NEW_CYCLE: Scheduling. (line 235) +* TARGET_SCHED_DFA_POST_ADVANCE_CYCLE: Scheduling. (line 160) +* TARGET_SCHED_DFA_POST_CYCLE_INSN: Scheduling. (line 144) +* TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE: Scheduling. (line 153) +* TARGET_SCHED_DFA_PRE_CYCLE_INSN: Scheduling. (line 132) +* TARGET_SCHED_DISPATCH: Scheduling. (line 355) +* TARGET_SCHED_DISPATCH_DO: Scheduling. (line 360) +* TARGET_SCHED_FINISH: Scheduling. (line 109) +* TARGET_SCHED_FINISH_GLOBAL: Scheduling. (line 126) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK: Scheduling. (line 215) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN: Scheduling. (line 204) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD: Scheduling. + (line 168) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD: Scheduling. + (line 196) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD_SPEC: Scheduling. + (line 328) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END: Scheduling. (line 220) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI: Scheduling. (line 230) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT: Scheduling. (line 225) +* TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE: Scheduling. (line 210) +* TARGET_SCHED_FREE_SCHED_CONTEXT: Scheduling. (line 293) +* TARGET_SCHED_GEN_SPEC_CHECK: Scheduling. (line 315) +* TARGET_SCHED_H_I_D_EXTENDED: Scheduling. (line 269) +* TARGET_SCHED_INIT: Scheduling. (line 99) +* TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN: Scheduling. (line 149) +* TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN: Scheduling. (line 141) +* TARGET_SCHED_INIT_GLOBAL: Scheduling. (line 118) +* TARGET_SCHED_INIT_SCHED_CONTEXT: Scheduling. (line 279) +* TARGET_SCHED_IS_COSTLY_DEPENDENCE: Scheduling. (line 246) +* TARGET_SCHED_ISSUE_RATE: Scheduling. (line 12) +* TARGET_SCHED_NEEDS_BLOCK_P: Scheduling. (line 308) +* TARGET_SCHED_REORDER: Scheduling. (line 60) +* TARGET_SCHED_REORDER2: Scheduling. (line 77) +* TARGET_SCHED_SET_SCHED_CONTEXT: Scheduling. (line 285) +* TARGET_SCHED_SET_SCHED_FLAGS: Scheduling. (line 340) +* TARGET_SCHED_SMS_RES_MII: Scheduling. (line 346) +* TARGET_SCHED_SPECULATE_INSN: Scheduling. (line 297) +* TARGET_SCHED_VARIABLE_ISSUE: Scheduling. (line 24) +* TARGET_SECONDARY_RELOAD: Register Classes. (line 316) +* TARGET_SECTION_TYPE_FLAGS: File Framework. (line 151) +* TARGET_SET_CURRENT_FUNCTION: Misc. (line 724) +* TARGET_SET_DEFAULT_TYPE_ATTRIBUTES: Target Attributes. (line 34) +* TARGET_SETUP_INCOMING_VARARGS: Varargs. (line 76) +* TARGET_SHIFT_TRUNCATION_MASK: Misc. (line 154) +* TARGET_SLOW_UNALIGNED_VECTOR_MEMOP: Misc. (line 665) +* TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P: Register Arguments. + (line 328) +* TARGET_SPLIT_COMPLEX_ARG: Register Arguments. (line 252) +* TARGET_STACK_PROTECT_FAIL: Stack Smashing Protection. + (line 17) +* TARGET_STACK_PROTECT_GUARD: Stack Smashing Protection. + (line 7) +* TARGET_STATIC_CHAIN: Frame Registers. (line 92) +* TARGET_STRICT_ARGUMENT_NAMING: Varargs. (line 112) +* TARGET_STRING_OBJECT_REF_TYPE_P: Run-time Target. (line 108) +* TARGET_STRIP_NAME_ENCODING: Sections. (line 282) +* TARGET_STRUCT_VALUE_RTX: Aggregate Return. (line 45) +* TARGET_SUPPORTS_SPLIT_STACK: Stack Smashing Protection. + (line 27) +* TARGET_SUPPORTS_WEAK: Label Output. (line 229) +* TARGET_TERMINATE_DW2_EH_FRAME_INFO: Exception Region Output. + (line 93) +* TARGET_TRAMPOLINE_ADJUST_ADDRESS: Trampolines. (line 75) +* TARGET_TRAMPOLINE_INIT: Trampolines. (line 56) +* TARGET_UNSPEC_MAY_TRAP_P: Misc. (line 716) +* TARGET_UNWIND_TABLES_DEFAULT: Exception Region Output. + (line 74) +* TARGET_UNWIND_WORD_MODE: Storage Layout. (line 457) +* TARGET_UPDATE_STACK_BOUNDARY: Misc. (line 967) +* TARGET_USE_ANCHORS_FOR_SYMBOL_P: Anchored Addresses. (line 55) +* TARGET_USE_BLOCKS_FOR_CONSTANT_P: Addressing Modes. (line 258) +* TARGET_USE_JCR_SECTION: Misc. (line 949) +* TARGET_USES_WEAK_UNWIND_INFO: Exception Handling. (line 129) +* TARGET_VALID_DLLIMPORT_ATTRIBUTE_P: Target Attributes. (line 68) +* TARGET_VALID_POINTER_MODE: Register Arguments. (line 297) +* TARGET_VECTOR_MODE_SUPPORTED_P: Register Arguments. (line 322) +* TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_SIZES: Addressing Modes. + (line 382) +* TARGET_VECTORIZE_BUILTIN_CONVERSION: Addressing Modes. (line 344) +* TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD: Addressing Modes. (line 274) +* TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_EVEN: Addressing Modes. (line 300) +* TARGET_VECTORIZE_BUILTIN_MUL_WIDEN_ODD: Addressing Modes. (line 312) +* TARGET_VECTORIZE_BUILTIN_VEC_PERM: Addressing Modes. (line 336) +* TARGET_VECTORIZE_BUILTIN_VEC_PERM_OK: Addressing Modes. (line 340) +* TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST: Addressing Modes. + (line 325) +* TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION: Addressing Modes. + (line 356) +* TARGET_VECTORIZE_PREFERRED_SIMD_MODE: Addressing Modes. (line 375) +* TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT: Addressing Modes. + (line 366) +* TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE: Addressing Modes. + (line 331) +* TARGET_VERSION: Run-time Target. (line 119) +* TARGET_VTABLE_DATA_ENTRY_DISTANCE: Type Layout. (line 330) +* TARGET_VTABLE_ENTRY_ALIGN: Type Layout. (line 324) +* TARGET_VTABLE_USES_DESCRIPTORS: Type Layout. (line 313) +* TARGET_WANT_DEBUG_PUB_SECTIONS: SDB and DWARF. (line 56) +* TARGET_WEAK_NOT_IN_ARCHIVE_TOC: Label Output. (line 265) +* targetm: Target Structure. (line 7) +* targets, makefile: Makefile. (line 6) +* TCmode: Machine Modes. (line 197) +* TDmode: Machine Modes. (line 94) +* TEMPLATE_DECL: Declarations. (line 6) +* Temporaries: Temporaries. (line 6) +* termination routines: Initialization. (line 6) +* testing constraints: C Constraint Interface. + (line 6) +* TEXT_SECTION_ASM_OP: Sections. (line 38) +* TF_SIZE: Type Layout. (line 131) +* TFmode: Machine Modes. (line 98) +* THEN_CLAUSE: Statements for C++. (line 6) +* THREAD_MODEL_SPEC: Driver. (line 163) +* THROW_EXPR: Unary and Binary Expressions. + (line 6) +* THUNK_DECL: Declarations. (line 6) +* THUNK_DELTA: Declarations. (line 6) +* TImode: Machine Modes. (line 48) +* TImode, in insn: Insns. (line 272) +* TLS_COMMON_ASM_OP: Sections. (line 82) +* TLS_SECTION_ASM_FLAG: Sections. (line 87) +* tm.h macros: Target Macros. (line 6) +* TQFmode: Machine Modes. (line 62) +* TQmode: Machine Modes. (line 119) +* TRAMPOLINE_ALIGNMENT: Trampolines. (line 49) +* TRAMPOLINE_SECTION: Trampolines. (line 40) +* TRAMPOLINE_SIZE: Trampolines. (line 45) +* trampolines for nested functions: Trampolines. (line 6) +* TRANSFER_FROM_TRAMPOLINE: Trampolines. (line 123) +* trap instruction pattern: Standard Names. (line 1381) +* tree <1>: Macros and Functions. + (line 6) +* tree: Tree overview. (line 6) +* Tree SSA: Tree SSA. (line 6) +* TREE_CHAIN: Macros and Functions. + (line 6) +* TREE_CODE: Tree overview. (line 6) +* tree_int_cst_equal: Constant expressions. + (line 6) +* TREE_INT_CST_HIGH: Constant expressions. + (line 6) +* TREE_INT_CST_LOW: Constant expressions. + (line 6) +* tree_int_cst_lt: Constant expressions. + (line 6) +* TREE_LIST: Containers. (line 6) +* TREE_OPERAND: Expression trees. (line 6) +* TREE_PUBLIC <1>: Function Basics. (line 6) +* TREE_PUBLIC: Function Properties. + (line 28) +* TREE_PURPOSE: Containers. (line 6) +* TREE_READONLY: Function Properties. + (line 37) +* tree_size: Macros and Functions. + (line 13) +* TREE_STATIC: Function Properties. + (line 31) +* TREE_STRING_LENGTH: Constant expressions. + (line 6) +* TREE_STRING_POINTER: Constant expressions. + (line 6) +* TREE_THIS_VOLATILE: Function Properties. + (line 34) +* TREE_TYPE <1>: Expression trees. (line 17) +* TREE_TYPE <2>: Macros and Functions. + (line 6) +* TREE_TYPE <3>: Types. (line 6) +* TREE_TYPE <4>: Function Basics. (line 47) +* TREE_TYPE <5>: Working with declarations. + (line 11) +* TREE_TYPE <6>: Types for C++. (line 6) +* TREE_TYPE: Expression trees. (line 6) +* TREE_VALUE: Containers. (line 6) +* TREE_VEC: Containers. (line 6) +* TREE_VEC_ELT: Containers. (line 6) +* TREE_VEC_LENGTH: Containers. (line 6) +* TRULY_NOOP_TRUNCATION: Misc. (line 177) +* TRUNC_DIV_EXPR: Unary and Binary Expressions. + (line 6) +* TRUNC_MOD_EXPR: Unary and Binary Expressions. + (line 6) +* truncate: Conversions. (line 38) +* truncMN2 instruction pattern: Standard Names. (line 834) +* TRUTH_AND_EXPR: Unary and Binary Expressions. + (line 6) +* TRUTH_ANDIF_EXPR: Unary and Binary Expressions. + (line 6) +* TRUTH_NOT_EXPR: Unary and Binary Expressions. + (line 6) +* TRUTH_OR_EXPR: Unary and Binary Expressions. + (line 6) +* TRUTH_ORIF_EXPR: Unary and Binary Expressions. + (line 6) +* TRUTH_XOR_EXPR: Unary and Binary Expressions. + (line 6) +* TRY_BLOCK: Statements for C++. (line 6) +* TRY_HANDLERS: Statements for C++. (line 6) +* TRY_STMTS: Statements for C++. (line 6) +* Tuple specific accessors: Tuple specific accessors. + (line 6) +* tuples: Tuple representation. + (line 6) +* type: Types. (line 6) +* type declaration: Declarations. (line 6) +* TYPE_ALIGN <1>: Types. (line 30) +* TYPE_ALIGN <2>: Types for C++. (line 6) +* TYPE_ALIGN: Types. (line 6) +* TYPE_ARG_TYPES <1>: Types for C++. (line 6) +* TYPE_ARG_TYPES: Types. (line 6) +* TYPE_ASM_OP: Label Output. (line 67) +* TYPE_ATTRIBUTES: Attributes. (line 25) +* TYPE_BINFO: Classes. (line 6) +* TYPE_BUILT_IN: Types for C++. (line 68) +* TYPE_CANONICAL: Types. (line 6) +* TYPE_CONTEXT <1>: Types for C++. (line 6) +* TYPE_CONTEXT: Types. (line 6) +* TYPE_DECL: Declarations. (line 6) +* TYPE_FIELDS <1>: Types for C++. (line 6) +* TYPE_FIELDS <2>: Classes. (line 6) +* TYPE_FIELDS: Types. (line 6) +* TYPE_HAS_ARRAY_NEW_OPERATOR: Classes. (line 96) +* TYPE_HAS_DEFAULT_CONSTRUCTOR: Classes. (line 81) +* TYPE_HAS_MUTABLE_P: Classes. (line 86) +* TYPE_HAS_NEW_OPERATOR: Classes. (line 93) +* TYPE_MAIN_VARIANT <1>: Types. (line 19) +* TYPE_MAIN_VARIANT: Types for C++. (line 6) +* TYPE_MAX_VALUE: Types. (line 6) +* TYPE_METHOD_BASETYPE <1>: Types for C++. (line 6) +* TYPE_METHOD_BASETYPE: Types. (line 6) +* TYPE_METHODS: Classes. (line 6) +* TYPE_MIN_VALUE: Types. (line 6) +* TYPE_NAME <1>: Types. (line 6) +* TYPE_NAME: Types for C++. (line 6) +* TYPE_NOTHROW_P: Functions for C++. (line 154) +* TYPE_OFFSET_BASETYPE <1>: Types. (line 6) +* TYPE_OFFSET_BASETYPE: Types for C++. (line 6) +* TYPE_OPERAND_FMT: Label Output. (line 78) +* TYPE_OVERLOADS_ARRAY_REF: Classes. (line 104) +* TYPE_OVERLOADS_ARROW: Classes. (line 107) +* TYPE_OVERLOADS_CALL_EXPR: Classes. (line 100) +* TYPE_POLYMORPHIC_P: Classes. (line 77) +* TYPE_PRECISION <1>: Types. (line 6) +* TYPE_PRECISION: Types for C++. (line 6) +* TYPE_PTR_P: Types for C++. (line 74) +* TYPE_PTRFN_P: Types for C++. (line 78) +* TYPE_PTRMEM_P: Types for C++. (line 6) +* TYPE_PTROB_P: Types for C++. (line 81) +* TYPE_PTROBV_P: Types for C++. (line 6) +* TYPE_QUAL_CONST <1>: Types for C++. (line 6) +* TYPE_QUAL_CONST: Types. (line 6) +* TYPE_QUAL_RESTRICT <1>: Types for C++. (line 6) +* TYPE_QUAL_RESTRICT: Types. (line 6) +* TYPE_QUAL_VOLATILE <1>: Types. (line 6) +* TYPE_QUAL_VOLATILE: Types for C++. (line 6) +* TYPE_RAISES_EXCEPTIONS: Functions for C++. (line 149) +* TYPE_SIZE <1>: Types for C++. (line 40) +* TYPE_SIZE: Types. (line 25) +* TYPE_STRUCTURAL_EQUALITY_P: Types. (line 6) +* TYPE_UNQUALIFIED <1>: Types. (line 6) +* TYPE_UNQUALIFIED: Types for C++. (line 6) +* TYPE_VFIELD: Classes. (line 6) +* TYPENAME_TYPE: Types for C++. (line 6) +* TYPENAME_TYPE_FULLNAME <1>: Types. (line 6) +* TYPENAME_TYPE_FULLNAME: Types for C++. (line 6) +* TYPEOF_TYPE: Types for C++. (line 6) +* UDAmode: Machine Modes. (line 168) +* udiv: Arithmetic. (line 130) +* udivM3 instruction pattern: Standard Names. (line 222) +* udivmodM4 instruction pattern: Standard Names. (line 455) +* udot_prodM instruction pattern: Standard Names. (line 292) +* UDQmode: Machine Modes. (line 136) +* UHAmode: Machine Modes. (line 160) +* UHQmode: Machine Modes. (line 128) +* UINT16_TYPE: Type Layout. (line 240) +* UINT32_TYPE: Type Layout. (line 241) +* UINT64_TYPE: Type Layout. (line 242) +* UINT8_TYPE: Type Layout. (line 239) +* UINT_FAST16_TYPE: Type Layout. (line 256) +* UINT_FAST32_TYPE: Type Layout. (line 257) +* UINT_FAST64_TYPE: Type Layout. (line 258) +* UINT_FAST8_TYPE: Type Layout. (line 255) +* UINT_LEAST16_TYPE: Type Layout. (line 248) +* UINT_LEAST32_TYPE: Type Layout. (line 249) +* UINT_LEAST64_TYPE: Type Layout. (line 250) +* UINT_LEAST8_TYPE: Type Layout. (line 247) +* UINTMAX_TYPE: Type Layout. (line 223) +* UINTPTR_TYPE: Type Layout. (line 260) +* umaddMN4 instruction pattern: Standard Names. (line 402) +* umax: Arithmetic. (line 149) +* umaxM3 instruction pattern: Standard Names. (line 222) +* umin: Arithmetic. (line 149) +* uminM3 instruction pattern: Standard Names. (line 222) +* umod: Arithmetic. (line 136) +* umodM3 instruction pattern: Standard Names. (line 222) +* umsubMN4 instruction pattern: Standard Names. (line 426) +* umulhisi3 instruction pattern: Standard Names. (line 374) +* umulM3_highpart instruction pattern: Standard Names. (line 388) +* umulqihi3 instruction pattern: Standard Names. (line 374) +* umulsidi3 instruction pattern: Standard Names. (line 374) +* unchanging: Flags. (line 324) +* unchanging, in call_insn: Flags. (line 19) +* unchanging, in jump_insn, call_insn and insn: Flags. (line 39) +* unchanging, in mem: Flags. (line 152) +* unchanging, in subreg: Flags. (line 188) +* unchanging, in symbol_ref: Flags. (line 10) +* UNEQ_EXPR: Unary and Binary Expressions. + (line 6) +* UNGE_EXPR: Unary and Binary Expressions. + (line 6) +* UNGT_EXPR: Unary and Binary Expressions. + (line 6) +* UNION_TYPE <1>: Types. (line 6) +* UNION_TYPE: Classes. (line 6) +* unions, returning: Interface. (line 10) +* UNITS_PER_WORD: Storage Layout. (line 60) +* UNKNOWN_TYPE <1>: Types for C++. (line 6) +* UNKNOWN_TYPE: Types. (line 6) +* UNLE_EXPR: Unary and Binary Expressions. + (line 6) +* UNLIKELY_EXECUTED_TEXT_SECTION_NAME: Sections. (line 49) +* UNLT_EXPR: Unary and Binary Expressions. + (line 6) +* UNORDERED_EXPR: Unary and Binary Expressions. + (line 6) +* unshare_all_rtl: Sharing. (line 58) +* unsigned division: Arithmetic. (line 130) +* unsigned division with unsigned saturation: Arithmetic. (line 130) +* unsigned greater than: Comparisons. (line 72) +* unsigned less than: Comparisons. (line 76) +* unsigned minimum and maximum: Arithmetic. (line 149) +* unsigned_fix: Conversions. (line 77) +* unsigned_float: Conversions. (line 62) +* unsigned_fract_convert: Conversions. (line 97) +* unsigned_sat_fract: Conversions. (line 103) +* unspec <1>: Constant Definitions. + (line 111) +* unspec: Side Effects. (line 287) +* unspec_volatile <1>: Constant Definitions. + (line 99) +* unspec_volatile: Side Effects. (line 287) +* untyped_call instruction pattern: Standard Names. (line 1012) +* untyped_return instruction pattern: Standard Names. (line 1062) +* UPDATE_PATH_HOST_CANONICALIZE (PATH): Filesystem. (line 59) +* update_ssa: SSA. (line 76) +* update_stmt <1>: Manipulating GIMPLE statements. + (line 141) +* update_stmt: SSA Operands. (line 6) +* update_stmt_if_modified: Manipulating GIMPLE statements. + (line 144) +* UQQmode: Machine Modes. (line 123) +* us_ashift: Arithmetic. (line 173) +* us_minus: Arithmetic. (line 36) +* us_mult: Arithmetic. (line 92) +* us_neg: Arithmetic. (line 81) +* us_plus: Arithmetic. (line 14) +* us_truncate: Conversions. (line 48) +* usaddM3 instruction pattern: Standard Names. (line 222) +* USAmode: Machine Modes. (line 164) +* usashlM3 instruction pattern: Standard Names. (line 458) +* usdivM3 instruction pattern: Standard Names. (line 222) +* use: Side Effects. (line 162) +* USE_C_ALLOCA: Host Misc. (line 19) +* USE_LD_AS_NEEDED: Driver. (line 136) +* USE_LOAD_POST_DECREMENT: Costs. (line 226) +* USE_LOAD_POST_INCREMENT: Costs. (line 221) +* USE_LOAD_PRE_DECREMENT: Costs. (line 236) +* USE_LOAD_PRE_INCREMENT: Costs. (line 231) +* use_param: GTY Options. (line 109) +* use_paramN: GTY Options. (line 127) +* use_params: GTY Options. (line 135) +* USE_SELECT_SECTION_FOR_FUNCTIONS: Sections. (line 195) +* USE_STORE_POST_DECREMENT: Costs. (line 246) +* USE_STORE_POST_INCREMENT: Costs. (line 241) +* USE_STORE_PRE_DECREMENT: Costs. (line 256) +* USE_STORE_PRE_INCREMENT: Costs. (line 251) +* used: Flags. (line 342) +* used, in symbol_ref: Flags. (line 215) +* USER_LABEL_PREFIX: Instruction Output. (line 154) +* USING_STMT: Statements for C++. (line 6) +* usmaddMN4 instruction pattern: Standard Names. (line 410) +* usmsubMN4 instruction pattern: Standard Names. (line 434) +* usmulhisi3 instruction pattern: Standard Names. (line 378) +* usmulM3 instruction pattern: Standard Names. (line 222) +* usmulqihi3 instruction pattern: Standard Names. (line 378) +* usmulsidi3 instruction pattern: Standard Names. (line 378) +* usnegM2 instruction pattern: Standard Names. (line 476) +* USQmode: Machine Modes. (line 132) +* ussubM3 instruction pattern: Standard Names. (line 222) +* usum_widenM3 instruction pattern: Standard Names. (line 302) +* UTAmode: Machine Modes. (line 172) +* UTQmode: Machine Modes. (line 140) +* V in constraint: Simple Constraints. (line 43) +* VA_ARG_EXPR: Unary and Binary Expressions. + (line 6) +* values, returned by functions: Scalar Return. (line 6) +* VAR_DECL: Declarations. (line 6) +* var_location: Debug Information. (line 14) +* varargs implementation: Varargs. (line 6) +* variable: Declarations. (line 6) +* Variable Location Debug Information in RTL: Debug Information. + (line 6) +* variable_size: GTY Options. (line 225) +* vashlM3 instruction pattern: Standard Names. (line 472) +* vashrM3 instruction pattern: Standard Names. (line 472) +* vec_concat: Vector Operations. (line 28) +* vec_duplicate: Vector Operations. (line 33) +* VEC_EXTRACT_EVEN_EXPR: Vectors. (line 6) +* vec_extract_evenM instruction pattern: Standard Names. (line 176) +* VEC_EXTRACT_ODD_EXPR: Vectors. (line 6) +* vec_extract_oddM instruction pattern: Standard Names. (line 183) +* vec_extractM instruction pattern: Standard Names. (line 171) +* vec_initM instruction pattern: Standard Names. (line 204) +* VEC_INTERLEAVE_HIGH_EXPR: Vectors. (line 6) +* vec_interleave_highM instruction pattern: Standard Names. (line 190) +* VEC_INTERLEAVE_LOW_EXPR: Vectors. (line 6) +* vec_interleave_lowM instruction pattern: Standard Names. (line 197) +* VEC_LSHIFT_EXPR: Vectors. (line 6) +* vec_merge: Vector Operations. (line 11) +* VEC_PACK_FIX_TRUNC_EXPR: Vectors. (line 6) +* VEC_PACK_SAT_EXPR: Vectors. (line 6) +* vec_pack_sfix_trunc_M instruction pattern: Standard Names. (line 329) +* vec_pack_ssat_M instruction pattern: Standard Names. (line 322) +* VEC_PACK_TRUNC_EXPR: Vectors. (line 6) +* vec_pack_trunc_M instruction pattern: Standard Names. (line 315) +* vec_pack_ufix_trunc_M instruction pattern: Standard Names. (line 329) +* vec_pack_usat_M instruction pattern: Standard Names. (line 322) +* VEC_RSHIFT_EXPR: Vectors. (line 6) +* vec_select: Vector Operations. (line 19) +* vec_setM instruction pattern: Standard Names. (line 166) +* vec_shl_M instruction pattern: Standard Names. (line 309) +* vec_shr_M instruction pattern: Standard Names. (line 309) +* VEC_UNPACK_FLOAT_HI_EXPR: Vectors. (line 6) +* VEC_UNPACK_FLOAT_LO_EXPR: Vectors. (line 6) +* VEC_UNPACK_HI_EXPR: Vectors. (line 6) +* VEC_UNPACK_LO_EXPR: Vectors. (line 6) +* vec_unpacks_float_hi_M instruction pattern: Standard Names. + (line 351) +* vec_unpacks_float_lo_M instruction pattern: Standard Names. + (line 351) +* vec_unpacks_hi_M instruction pattern: Standard Names. (line 336) +* vec_unpacks_lo_M instruction pattern: Standard Names. (line 336) +* vec_unpacku_float_hi_M instruction pattern: Standard Names. + (line 351) +* vec_unpacku_float_lo_M instruction pattern: Standard Names. + (line 351) +* vec_unpacku_hi_M instruction pattern: Standard Names. (line 344) +* vec_unpacku_lo_M instruction pattern: Standard Names. (line 344) +* VEC_WIDEN_MULT_HI_EXPR: Vectors. (line 6) +* VEC_WIDEN_MULT_LO_EXPR: Vectors. (line 6) +* vec_widen_smult_hi_M instruction pattern: Standard Names. (line 360) +* vec_widen_smult_lo_M instruction pattern: Standard Names. (line 360) +* vec_widen_umult_hi_M instruction pattern: Standard Names. (line 360) +* vec_widen_umult_lo__M instruction pattern: Standard Names. (line 360) +* vector: Containers. (line 6) +* vector operations: Vector Operations. (line 6) +* VECTOR_CST: Constant expressions. + (line 6) +* VECTOR_STORE_FLAG_VALUE: Misc. (line 308) +* virtual operands: SSA Operands. (line 6) +* VIRTUAL_INCOMING_ARGS_REGNUM: Regs and Memory. (line 59) +* VIRTUAL_OUTGOING_ARGS_REGNUM: Regs and Memory. (line 87) +* VIRTUAL_STACK_DYNAMIC_REGNUM: Regs and Memory. (line 78) +* VIRTUAL_STACK_VARS_REGNUM: Regs and Memory. (line 69) +* VLIW: Processor pipeline description. + (line 6) +* vlshrM3 instruction pattern: Standard Names. (line 472) +* VMS: Filesystem. (line 37) +* VMS_DEBUGGING_INFO: VMS Debug. (line 9) +* VOID_TYPE: Types. (line 6) +* VOIDmode: Machine Modes. (line 190) +* volatil: Flags. (line 356) +* volatil, in insn, call_insn, jump_insn, code_label, barrier, and note: Flags. + (line 44) +* volatil, in label_ref and reg_label: Flags. (line 65) +* volatil, in mem, asm_operands, and asm_input: Flags. (line 94) +* volatil, in reg: Flags. (line 116) +* volatil, in subreg: Flags. (line 188) +* volatil, in symbol_ref: Flags. (line 224) +* volatile memory references: Flags. (line 357) +* volatile, in prefetch: Flags. (line 232) +* voting between constraint alternatives: Class Preferences. (line 6) +* vrotlM3 instruction pattern: Standard Names. (line 472) +* vrotrM3 instruction pattern: Standard Names. (line 472) +* walk_dominator_tree: SSA. (line 256) +* walk_gimple_op: Statement and operand traversals. + (line 32) +* walk_gimple_seq: Statement and operand traversals. + (line 50) +* walk_gimple_stmt: Statement and operand traversals. + (line 13) +* walk_use_def_chains: SSA. (line 232) +* WCHAR_TYPE: Type Layout. (line 191) +* WCHAR_TYPE_SIZE: Type Layout. (line 199) +* which_alternative: Output Statement. (line 59) +* WHILE_BODY: Statements for C++. (line 6) +* WHILE_COND: Statements for C++. (line 6) +* WHILE_STMT: Statements for C++. (line 6) +* whopr: LTO. (line 6) +* WIDEST_HARDWARE_FP_SIZE: Type Layout. (line 146) +* WINT_TYPE: Type Layout. (line 204) +* word_mode: Machine Modes. (line 336) +* WORD_REGISTER_OPERATIONS: Misc. (line 63) +* WORDS_BIG_ENDIAN: Storage Layout. (line 29) +* WORDS_BIG_ENDIAN, effect on subreg: Regs and Memory. (line 217) +* wpa: LTO. (line 6) +* X in constraint: Simple Constraints. (line 124) +* x-HOST: Host Fragment. (line 6) +* XCmode: Machine Modes. (line 197) +* XCOFF_DEBUGGING_INFO: DBX Options. (line 13) +* XEXP: Accessors. (line 6) +* XF_SIZE: Type Layout. (line 130) +* XFmode: Machine Modes. (line 79) +* XINT: Accessors. (line 6) +* xm-MACHINE.h <1>: Host Misc. (line 6) +* xm-MACHINE.h: Filesystem. (line 6) +* xor: Arithmetic. (line 168) +* xor, canonicalization of: Insn Canonicalizations. + (line 79) +* xorM3 instruction pattern: Standard Names. (line 222) +* XSTR: Accessors. (line 6) +* XVEC: Accessors. (line 41) +* XVECEXP: Accessors. (line 48) +* XVECLEN: Accessors. (line 44) +* XWINT: Accessors. (line 6) +* zero_extend: Conversions. (line 28) +* zero_extendMN2 instruction pattern: Standard Names. (line 844) +* zero_extract: Bit-Fields. 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