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Diffstat (limited to 'src/Unwind/UnwindLevel1.c')
| -rw-r--r-- | src/Unwind/UnwindLevel1.c | 495 |
1 files changed, 495 insertions, 0 deletions
diff --git a/src/Unwind/UnwindLevel1.c b/src/Unwind/UnwindLevel1.c new file mode 100644 index 0000000..b2e93c7 --- /dev/null +++ b/src/Unwind/UnwindLevel1.c @@ -0,0 +1,495 @@ +//===------------------------- UnwindLevel1.c -----------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.TXT for details. +// +// +// Implements C++ ABI Exception Handling Level 1 as documented at: +// http://mentorembedded.github.io/cxx-abi/abi-eh.html +// using libunwind +// +//===----------------------------------------------------------------------===// + +#include <stdint.h> +#include <stdbool.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> + +#include "libunwind.h" +#include "unwind.h" +#include "config.h" + +#if _LIBUNWIND_BUILD_ZERO_COST_APIS + +static _Unwind_Reason_Code +unwind_phase1(unw_context_t *uc, struct _Unwind_Exception *exception_object) { + unw_cursor_t cursor1; + unw_init_local(&cursor1, uc); + + // Walk each frame looking for a place to stop. + for (bool handlerNotFound = true; handlerNotFound;) { + + // Ask libuwind to get next frame (skip over first which is + // _Unwind_RaiseException). + int stepResult = unw_step(&cursor1); + if (stepResult == 0) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step() reached " + "bottom => _URC_END_OF_STACK\n", + exception_object); + return _URC_END_OF_STACK; + } else if (stepResult < 0) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step failed => " + "_URC_FATAL_PHASE1_ERROR\n", + exception_object); + return _URC_FATAL_PHASE1_ERROR; + } + + // See if frame has code to run (has personality routine). + unw_proc_info_t frameInfo; + unw_word_t sp; + if (unw_get_proc_info(&cursor1, &frameInfo) != UNW_ESUCCESS) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_get_proc_info " + "failed => _URC_FATAL_PHASE1_ERROR\n", + exception_object); + return _URC_FATAL_PHASE1_ERROR; + } + + // When tracing, print state information. + if (_LIBUNWIND_TRACING_UNWINDING) { + char functionName[512]; + unw_word_t offset; + if ((unw_get_proc_name(&cursor1, functionName, 512, &offset) != + UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip)) + strcpy(functionName, ".anonymous."); + unw_word_t pc; + unw_get_reg(&cursor1, UNW_REG_IP, &pc); + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase1(ex_ojb=%p): pc=0x%llX, start_ip=0x%llX, func=%s, " + "lsda=0x%llX, personality=0x%llX\n", + exception_object, pc, frameInfo.start_ip, functionName, + frameInfo.lsda, frameInfo.handler); + } + + // If there is a personality routine, ask it if it will want to stop at + // this frame. + if (frameInfo.handler != 0) { + __personality_routine p = + (__personality_routine)(long)(frameInfo.handler); + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase1(ex_ojb=%p): calling personality function %p\n", + exception_object, p); + _Unwind_Reason_Code personalityResult = + (*p)(1, _UA_SEARCH_PHASE, exception_object->exception_class, + exception_object, (struct _Unwind_Context *)(&cursor1)); + switch (personalityResult) { + case _URC_HANDLER_FOUND: + // found a catch clause or locals that need destructing in this frame + // stop search and remember stack pointer at the frame + handlerNotFound = false; + unw_get_reg(&cursor1, UNW_REG_SP, &sp); + exception_object->private_2 = (uintptr_t)sp; + _LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): " + "_URC_HANDLER_FOUND \n", + exception_object); + return _URC_NO_REASON; + + case _URC_CONTINUE_UNWIND: + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND\n", + exception_object); + // continue unwinding + break; + + default: + // something went wrong + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR\n", + exception_object); + return _URC_FATAL_PHASE1_ERROR; + } + } + } + return _URC_NO_REASON; +} + + +static _Unwind_Reason_Code +unwind_phase2(unw_context_t *uc, struct _Unwind_Exception *exception_object) { + unw_cursor_t cursor2; + unw_init_local(&cursor2, uc); + + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)\n", exception_object); + + // Walk each frame until we reach where search phase said to stop. + while (true) { + + // Ask libuwind to get next frame (skip over first which is + // _Unwind_RaiseException). + int stepResult = unw_step(&cursor2); + if (stepResult == 0) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step() reached " + "bottom => _URC_END_OF_STACK\n", + exception_object); + return _URC_END_OF_STACK; + } else if (stepResult < 0) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step failed => " + "_URC_FATAL_PHASE1_ERROR\n", + exception_object); + return _URC_FATAL_PHASE2_ERROR; + } + + // Get info about this frame. + unw_word_t sp; + unw_proc_info_t frameInfo; + unw_get_reg(&cursor2, UNW_REG_SP, &sp); + if (unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_get_proc_info " + "failed => _URC_FATAL_PHASE1_ERROR\n", + exception_object); + return _URC_FATAL_PHASE2_ERROR; + } + + // When tracing, print state information. + if (_LIBUNWIND_TRACING_UNWINDING) { + char functionName[512]; + unw_word_t offset; + if ((unw_get_proc_name(&cursor2, functionName, 512, &offset) != + UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip)) + strcpy(functionName, ".anonymous."); + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase2(ex_ojb=%p): start_ip=0x%llX, func=%s, sp=0x%llX, " + "lsda=0x%llX, personality=0x%llX\n", + exception_object, frameInfo.start_ip, functionName, sp, + frameInfo.lsda, frameInfo.handler); + } + + // If there is a personality routine, tell it we are unwinding. + if (frameInfo.handler != 0) { + __personality_routine p = + (__personality_routine)(long)(frameInfo.handler); + _Unwind_Action action = _UA_CLEANUP_PHASE; + if (sp == exception_object->private_2) { + // Tell personality this was the frame it marked in phase 1. + action = (_Unwind_Action)(_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME); + } + _Unwind_Reason_Code personalityResult = + (*p)(1, action, exception_object->exception_class, exception_object, + (struct _Unwind_Context *)(&cursor2)); + switch (personalityResult) { + case _URC_CONTINUE_UNWIND: + // Continue unwinding + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND\n", + exception_object); + if (sp == exception_object->private_2) { + // Phase 1 said we would stop at this frame, but we did not... + _LIBUNWIND_ABORT("during phase1 personality function said it would " + "stop here, but now if phase2 it did not stop here"); + } + break; + case _URC_INSTALL_CONTEXT: + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT\n", + exception_object); + // Personality routine says to transfer control to landing pad. + // We may get control back if landing pad calls _Unwind_Resume(). + if (_LIBUNWIND_TRACING_UNWINDING) { + unw_word_t pc; + unw_get_reg(&cursor2, UNW_REG_IP, &pc); + unw_get_reg(&cursor2, UNW_REG_SP, &sp); + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering " + "user code with ip=0x%llX, sp=0x%llX\n", + exception_object, pc, sp); + } + unw_resume(&cursor2); + // unw_resume() only returns if there was an error. + return _URC_FATAL_PHASE2_ERROR; + default: + // Personality routine returned an unknown result code. + _LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d", + personalityResult); + return _URC_FATAL_PHASE2_ERROR; + } + } + } + + // Clean up phase did not resume at the frame that the search phase + // said it would... + return _URC_FATAL_PHASE2_ERROR; +} + +static _Unwind_Reason_Code +unwind_phase2_forced(unw_context_t *uc, + struct _Unwind_Exception *exception_object, + _Unwind_Stop_Fn stop, void *stop_parameter) { + unw_cursor_t cursor2; + unw_init_local(&cursor2, uc); + + // Walk each frame until we reach where search phase said to stop + while (unw_step(&cursor2) > 0) { + + // Update info about this frame. + unw_proc_info_t frameInfo; + if (unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) { + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): unw_step " + "failed => _URC_END_OF_STACK\n", + exception_object); + return _URC_FATAL_PHASE1_ERROR; + } + + // When tracing, print state information. + if (_LIBUNWIND_TRACING_UNWINDING) { + char functionName[512]; + unw_word_t offset; + if ((unw_get_proc_name(&cursor2, functionName, 512, &offset) != + UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip)) + strcpy(functionName, ".anonymous."); + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): " + "start_ip=0x%llX, func=%s, lsda=0x%llX, " + " personality=0x%llX\n", + exception_object, frameInfo.start_ip, + functionName, frameInfo.lsda, + frameInfo.handler); + } + + // Call stop function at each frame. + _Unwind_Action action = + (_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE); + _Unwind_Reason_Code stopResult = + (*stop)(1, action, exception_object->exception_class, exception_object, + (struct _Unwind_Context *)(&cursor2), stop_parameter); + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase2_forced(ex_ojb=%p): stop function returned %d\n", + exception_object, stopResult); + if (stopResult != _URC_NO_REASON) { + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase2_forced(ex_ojb=%p): stopped by stop function\n", + exception_object); + return _URC_FATAL_PHASE2_ERROR; + } + + // If there is a personality routine, tell it we are unwinding. + if (frameInfo.handler != 0) { + __personality_routine p = + (__personality_routine)(long)(frameInfo.handler); + _LIBUNWIND_TRACE_UNWINDING( + "unwind_phase2_forced(ex_ojb=%p): calling personality function %p\n", + exception_object, p); + _Unwind_Reason_Code personalityResult = + (*p)(1, action, exception_object->exception_class, exception_object, + (struct _Unwind_Context *)(&cursor2)); + switch (personalityResult) { + case _URC_CONTINUE_UNWIND: + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): " + "personality returned _URC_CONTINUE_UNWIND\n", + exception_object); + // Destructors called, continue unwinding + break; + case _URC_INSTALL_CONTEXT: + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): " + "personality returned _URC_INSTALL_CONTEXT\n", + exception_object); + // We may get control back if landing pad calls _Unwind_Resume(). + unw_resume(&cursor2); + break; + default: + // Personality routine returned an unknown result code. + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): " + "personality returned %d, " + "_URC_FATAL_PHASE2_ERROR\n", + exception_object, personalityResult); + return _URC_FATAL_PHASE2_ERROR; + } + } + } + + // Call stop function one last time and tell it we've reached the end + // of the stack. + _LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): calling stop " + "function with _UA_END_OF_STACK\n", + exception_object); + _Unwind_Action lastAction = + (_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE | _UA_END_OF_STACK); + (*stop)(1, lastAction, exception_object->exception_class, exception_object, + (struct _Unwind_Context *)(&cursor2), stop_parameter); + + // Clean up phase did not resume at the frame that the search phase said it + // would. + return _URC_FATAL_PHASE2_ERROR; +} + + +/// Called by __cxa_throw. Only returns if there is a fatal error. +_LIBUNWIND_EXPORT _Unwind_Reason_Code +_Unwind_RaiseException(struct _Unwind_Exception *exception_object) { + _LIBUNWIND_TRACE_API("_Unwind_RaiseException(ex_obj=%p)\n", + exception_object); + unw_context_t uc; + unw_getcontext(&uc); + + // Mark that this is a non-forced unwind, so _Unwind_Resume() + // can do the right thing. + exception_object->private_1 = 0; + exception_object->private_2 = 0; + + // phase 1: the search phase + _Unwind_Reason_Code phase1 = unwind_phase1(&uc, exception_object); + if (phase1 != _URC_NO_REASON) + return phase1; + + // phase 2: the clean up phase + return unwind_phase2(&uc, exception_object); +} + + + +/// When _Unwind_RaiseException() is in phase2, it hands control +/// to the personality function at each frame. The personality +/// may force a jump to a landing pad in that function, the landing +/// pad code may then call _Unwind_Resume() to continue with the +/// unwinding. Note: the call to _Unwind_Resume() is from compiler +/// geneated user code. All other _Unwind_* routines are called +/// by the C++ runtime __cxa_* routines. +/// +/// Note: re-throwing an exception (as opposed to continuing the unwind) +/// is implemented by having the code call __cxa_rethrow() which +/// in turn calls _Unwind_Resume_or_Rethrow(). +_LIBUNWIND_EXPORT void +_Unwind_Resume(struct _Unwind_Exception *exception_object) { + _LIBUNWIND_TRACE_API("_Unwind_Resume(ex_obj=%p)\n", exception_object); + unw_context_t uc; + unw_getcontext(&uc); + + if (exception_object->private_1 != 0) + unwind_phase2_forced(&uc, exception_object, + (_Unwind_Stop_Fn) exception_object->private_1, + (void *)exception_object->private_2); + else + unwind_phase2(&uc, exception_object); + + // Clients assume _Unwind_Resume() does not return, so all we can do is abort. + _LIBUNWIND_ABORT("_Unwind_Resume() can't return"); +} + + + +/// Not used by C++. +/// Unwinds stack, calling "stop" function at each frame. +/// Could be used to implement longjmp(). +_LIBUNWIND_EXPORT _Unwind_Reason_Code +_Unwind_ForcedUnwind(struct _Unwind_Exception *exception_object, + _Unwind_Stop_Fn stop, void *stop_parameter) { + _LIBUNWIND_TRACE_API("_Unwind_ForcedUnwind(ex_obj=%p, stop=%p)\n", + exception_object, stop); + unw_context_t uc; + unw_getcontext(&uc); + + // Mark that this is a forced unwind, so _Unwind_Resume() can do + // the right thing. + exception_object->private_1 = (uintptr_t) stop; + exception_object->private_2 = (uintptr_t) stop_parameter; + + // do it + return unwind_phase2_forced(&uc, exception_object, stop, stop_parameter); +} + + +/// Called by personality handler during phase 2 to get LSDA for current frame. +_LIBUNWIND_EXPORT uintptr_t +_Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) { + unw_cursor_t *cursor = (unw_cursor_t *)context; + unw_proc_info_t frameInfo; + uintptr_t result = 0; + if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) + result = (uintptr_t)frameInfo.lsda; + _LIBUNWIND_TRACE_API("_Unwind_GetLanguageSpecificData(context=%p)" + "=> 0x%lX\n", context, result); + if (result != 0) { + if (*((uint8_t *)result) != 0xFF) + _LIBUNWIND_DEBUG_LOG("lsda at 0x%lX does not start with 0xFF\n", result); + } + return result; +} + + + +/// Called by personality handler during phase 2 to get register values. +_LIBUNWIND_EXPORT uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, + int index) { + unw_cursor_t *cursor = (unw_cursor_t *)context; + unw_word_t result; + unw_get_reg(cursor, index, &result); + _LIBUNWIND_TRACE_API("_Unwind_GetGR(context=%p, reg=%d) => 0x%llX\n", + context, + index, (uint64_t) result); + return (uintptr_t)result; +} + + + +/// Called by personality handler during phase 2 to alter register values. +_LIBUNWIND_EXPORT void _Unwind_SetGR(struct _Unwind_Context *context, int index, + uintptr_t new_value) { + _LIBUNWIND_TRACE_API("_Unwind_SetGR(context=%p, reg=%d, " + "value=0x%0llX)\n", context, + index, (uint64_t) new_value); + unw_cursor_t *cursor = (unw_cursor_t *)context; + unw_set_reg(cursor, index, new_value); +} + + + +/// Called by personality handler during phase 2 to get instruction pointer. +_LIBUNWIND_EXPORT uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) { + unw_cursor_t *cursor = (unw_cursor_t *)context; + unw_word_t result; + unw_get_reg(cursor, UNW_REG_IP, &result); + _LIBUNWIND_TRACE_API("_Unwind_GetIP(context=%p) => 0x%llX\n", context, + (uint64_t) result); + return (uintptr_t)result; +} + + + +/// Called by personality handler during phase 2 to alter instruction pointer, +/// such as setting where the landing pad is, so _Unwind_Resume() will +/// start executing in the landing pad. +_LIBUNWIND_EXPORT void _Unwind_SetIP(struct _Unwind_Context *context, + uintptr_t new_value) { + _LIBUNWIND_TRACE_API("_Unwind_SetIP(context=%p, value=0x%0llX)\n", + context, (uint64_t) new_value); + unw_cursor_t *cursor = (unw_cursor_t *)context; + unw_set_reg(cursor, UNW_REG_IP, new_value); +} + + +/// Called by personality handler during phase 2 to find the start of the +/// function. +_LIBUNWIND_EXPORT uintptr_t +_Unwind_GetRegionStart(struct _Unwind_Context *context) { + unw_cursor_t *cursor = (unw_cursor_t *)context; + unw_proc_info_t frameInfo; + uintptr_t result = 0; + if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS) + result = (uintptr_t)frameInfo.start_ip; + _LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%lX\n", + context, result); + return result; +} + + +/// Called by personality handler during phase 2 if a foreign exception +// is caught. +_LIBUNWIND_EXPORT void +_Unwind_DeleteException(struct _Unwind_Exception *exception_object) { + _LIBUNWIND_TRACE_API("_Unwind_DeleteException(ex_obj=%p)\n", + exception_object); + if (exception_object->exception_cleanup != NULL) + (*exception_object->exception_cleanup)(_URC_FOREIGN_EXCEPTION_CAUGHT, + exception_object); +} + +#endif // _LIBUNWIND_BUILD_ZERO_COST_APIS |