[ndk][conf] Make an llvm-config for cross-compilation

The llvm-config-host program that was installed wasn't
host-related at all; it runs on build and also reports
about build. This program is still needed for the build
to work, so a new BuildToolsCross folder is created and
in there, an llvm-config is built that runs on build
and reports about host.

For this to work, the Makefile that generates llvm-config
and the one that generates BuildVariables.inc must not be
the same, so Makefile.buildvars is used, and an extra var
CROSS_DEPTH is used to enable BuildToolsCross to step one
folder higher up into the top-level build folder to get
the correct values to be emitted into BuildVariables.inc.

The old BuildTools/*/bin/llvm-config is now installed
as llvm-config-build, and the new one is installed as
llvm-config-host

This change has also been submitted to llvm-commits ML:

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130826/185708.html

Cherry-picked from release_33 branch.

Change-Id: Icc630908044c8bd54166bfbe7295414d7f22793b

5 files changed, 104 insertions, 25 deletions

diff --git a/Makefile b/Makefile
index b84553a70c1..f6603105816 100644
--- a/Makefile
+++ b/Makefile
@@ -104,8 +104,10 @@ ifeq ($(LLVM_CROSS_COMPILING),1)
 all:: cross-compile-build-tools
 
 clean::
-	$(Verb) rm -rf BuildTools
+	$(Verb) rm -rf BuildTools BuildToolsCross
 
+# BuildToolsCross is built the same as BuildTools except
+# that CROSS_DEPTH is ../ for BuildToolsCross
 cross-compile-build-tools:
 	$(Verb) if [ ! -f BuildTools/Makefile ]; then \
           $(MKDIR) BuildTools; \
@@ -135,6 +137,36 @@ cross-compile-build-tools:
 	  ENABLE_LIBCPP=$(ENABLE_LIBCPP) \
 	  CFLAGS= \
 	  CXXFLAGS= \
+	) || exit 1; \
+	if [ ! -f BuildToolsCross/Makefile ]; then \
+          $(MKDIR) BuildToolsCross; \
+	  cd BuildToolsCross ; \
+	  unset CFLAGS ; \
+	  unset CXXFLAGS ; \
+	  unset LDFLAGS ; \
+	  unset SDKROOT ; \
+	  unset UNIVERSAL_SDK_PATH ; \
+	  $(PROJ_SRC_DIR)/configure --build=$(BUILD_TRIPLE) \
+		--host=$(BUILD_TRIPLE) --target=$(BUILD_TRIPLE) \
+	        --disable-polly ; \
+	  cd .. ; \
+	fi; \
+	($(MAKE) -C BuildToolsCross \
+	  BUILD_DIRS_ONLY=1 \
+	  UNIVERSAL= \
+	  UNIVERSAL_SDK_PATH= \
+	  SDKROOT= \
+	  TARGET_NATIVE_ARCH="$(TARGET_NATIVE_ARCH)" \
+	  TARGETS_TO_BUILD="$(TARGETS_TO_BUILD)" \
+	  ENABLE_OPTIMIZED=$(ENABLE_OPTIMIZED) \
+	  ENABLE_PROFILING=$(ENABLE_PROFILING) \
+	  ENABLE_COVERAGE=$(ENABLE_COVERAGE) \
+	  DISABLE_ASSERTIONS=$(DISABLE_ASSERTIONS) \
+	  ENABLE_EXPENSIVE_CHECKS=$(ENABLE_EXPENSIVE_CHECKS) \
+	  ENABLE_LIBCPP=$(ENABLE_LIBCPP) \
+	  CFLAGS= \
+	  CXXFLAGS= \
+	  CROSS_DEPTH=../ \
 	) || exit 1;
 endif
 
diff --git a/Makefile.rules b/Makefile.rules
index 68f6cf8ec5d..df06d3a3046 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -465,6 +465,7 @@ endif
 TargetMode :=
 ifeq ($(LLVM_CROSS_COMPILING),1)
   BuildLLVMToolDir := $(LLVM_OBJ_ROOT)/BuildTools/$(BuildMode)/bin
+  BuildLLVMCrossToolDir := $(LLVM_OBJ_ROOT)/BuildToolsCross/$(BuildMode)/bin
 endif
 
 ObjRootDir  := $(PROJ_OBJ_DIR)/$(BuildMode)
@@ -842,7 +843,7 @@ $(RecursiveTargets)::
 	  if ([ ! -f $$dir/Makefile ] || \
 	      command test $$dir/Makefile -ot $(PROJ_SRC_DIR)/$$dir/Makefile ); then \
 	    $(MKDIR) $$dir; \
-	    $(CP) $(PROJ_SRC_DIR)/$$dir/Makefile $$dir/Makefile; \
+	    $(CP) $(PROJ_SRC_DIR)/$$dir/Makefile* $$dir/; \
 	  fi; \
 	  ($(MAKE) -C $$dir $@ ) || exit 1; \
 	done
diff --git a/projects/sample/Makefile.llvm.rules b/projects/sample/Makefile.llvm.rules
index 545e629cf34..e9857fb0a22 100644
--- a/projects/sample/Makefile.llvm.rules
+++ b/projects/sample/Makefile.llvm.rules
@@ -406,6 +406,7 @@ endif
 TargetMode :=
 ifeq ($(LLVM_CROSS_COMPILING),1)
   BuildLLVMToolDir := $(LLVM_OBJ_ROOT)/BuildTools/$(BuildMode)/bin
+  BuildLLVMCrossToolDir := $(LLVM_OBJ_ROOT)/BuildToolsCross/$(BuildMode)/bin
 endif
 
 ObjRootDir  := $(PROJ_OBJ_DIR)/$(BuildMode)
diff --git a/tools/llvm-config/Makefile b/tools/llvm-config/Makefile
index b20b6bf4a4b..5f1f81b3f1b 100644
--- a/tools/llvm-config/Makefile
+++ b/tools/llvm-config/Makefile
@@ -35,33 +35,17 @@ SUB_CXXFLAGS := ${CPP.BaseFlags} ${CXX.Flags}
 # user to use libtool when linking against LLVM.
 SUB_LDFLAGS :=
 
-$(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile $(ObjDir)/.dir
-	$(Echo) "Building llvm-config BuildVariables.inc file."
-	$(Verb) $(ECHO) 's/@LLVM_SRC_ROOT@/$(subst /,\/,$(LLVM_SRC_ROOT))/' \
-	  > temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_OBJ_ROOT@/$(subst /,\/,$(LLVM_OBJ_ROOT))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_CPPFLAGS@/$(subst /,\/,$(SUB_CPPFLAGS))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_CFLAGS@/$(subst /,\/,$(SUB_CFLAGS))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_CXXFLAGS@/$(subst /,\/,$(SUB_CXXFLAGS))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_LDFLAGS@/$(subst /,\/,$(SUB_LDFLAGS))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_BUILDMODE@/$(subst /,\/,$(BuildMode))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_SYSTEM_LIBS@/$(subst /,\/,$(LIBS))/' \
-	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_TARGETS_BUILT@/$(subst /,\/,$(TARGETS_TO_BUILD))/' \
-	  >> temp.sed
-	$(Verb) $(SED) -f temp.sed < $< > $@
-	$(Verb) $(RM) temp.sed
+$(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile Makefile.buildvars $(ObjDir)/.dir
+	$(Echo) "Making llvm-config $@ file."
+	$(MAKE) -f Makefile.buildvars CROSS_DEPTH=$(CROSS_DEPTH)
 
 # When cross-compiling, install a version of llvm-config that runs on the host.
 ifeq ($(LLVM_CROSS_COMPILING),1)
 install:: $(DESTDIR)$(PROJ_bindir)
 	$(Echo) Installing llvm-config-host
 	$(Verb) $(ProgInstall) $(BuildLLVMToolDir)/llvm-config \
-	  $(DESTDIR)$(PROJ_bindir)/$(program_prefix)llvm-config-host
+	  $(DESTDIR)$(PROJ_bindir)/$(program_prefix)llvm-config-build
+	$(Echo) Installing llvm-config-host
+	$(Verb) $(ProgInstall) $(BuildLLVMCrossToolDir)/llvm-config \
+		$(DESTDIR)$(PROJ_bindir)/$(program_prefix)llvm-config-host
 endif
diff --git a/tools/llvm-config/Makefile.buildvars b/tools/llvm-config/Makefile.buildvars
new file mode 100644
index 00000000000..92098cacb2d
--- /dev/null
+++ b/tools/llvm-config/Makefile.buildvars
@@ -0,0 +1,61 @@
+##===- tools/llvm-config/Makefile.buildvars-----------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL := $(CROSS_DEPTH)../..
+TOOLNAME :=
+USEDLIBS :=
+
+# We generate sources in the build directory, make sure it is in the include
+# paths.
+INCLUDE_BUILD_DIR := 1
+
+# This tool has no plugins, optimize startup time.
+TOOL_NO_EXPORTS := 1
+
+# Note that we have to use lazy expansion here.
+BUILDVARIABLES_SRCPATH = $(PROJ_SRC_ROOT)/tools/llvm-config/BuildVariables.inc.in
+BUILDVARIABLES_OBJPATH = $(ObjDir)/BuildVariables.inc
+BUILT_SOURCES = $(BUILDVARIABLES_OBJPATH)
+
+include $(LEVEL)/Makefile.common
+
+# Combine preprocessor flags (except for -I) and CXX flags.
+SUB_CPPFLAGS := ${CPP.BaseFlags}
+SUB_CFLAGS   := ${CPP.BaseFlags} ${C.Flags}
+SUB_CXXFLAGS := ${CPP.BaseFlags} ${CXX.Flags}
+
+# This is blank for now.  We need to be careful about adding stuff here:
+# LDFLAGS tend not to be portable, and we don't currently require the
+# user to use libtool when linking against LLVM.
+SUB_LDFLAGS :=
+
+$(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile.buildvars
+	$(Echo) "Building llvm-config $@ file."
+	$(Verb) $(ECHO) 's/@LLVM_SRC_ROOT@/$(subst /,\/,$(LLVM_SRC_ROOT))/' \
+	  > temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_OBJ_ROOT@/$(subst /,\/,$(LLVM_OBJ_ROOT))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_CPPFLAGS@/$(subst /,\/,$(SUB_CPPFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_CFLAGS@/$(subst /,\/,$(SUB_CFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_CXXFLAGS@/$(subst /,\/,$(SUB_CXXFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_LDFLAGS@/$(subst /,\/,$(SUB_LDFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_BUILDMODE@/$(subst /,\/,$(BuildMode))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_SYSTEM_LIBS@/$(subst /,\/,$(LIBS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_TARGETS_BUILT@/$(subst /,\/,$(TARGETS_TO_BUILD))/' \
+	  >> temp.sed
+	$(Verb) $(SED) -f temp.sed < $< > $@
+	$(Verb) $(RM) temp.sed
+
+all:: $(ObjDir)/BuildVariables.inc