auto merge of #8695 : thestinger/rust/build, r=pcwalton

We currently have no need for the frame pointers on any platform. They
may eventually be needed on platforms without an equivalent to the DWARF
call frame information to walk the stack in the garbage collector.

Closes #7477

Author: bors

mk/llvm.mk

@@ -26,7 +26,7 @@ ifeq ($(CFG_LLVM_ROOT),)
 
 $$(LLVM_CONFIG_$(1)): $$(LLVM_DEPS)
 	@$$(call E, make: llvm)
-	$$(Q)$$(MAKE) -C $$(CFG_LLVM_BUILD_DIR_$(1)) $$(CFG_LLVM_BUILD_ENV)
+	$$(Q)$$(MAKE) -C $$(CFG_LLVM_BUILD_DIR_$(1))
 	$$(Q)touch $$(LLVM_CONFIG_$(1))
 endif
 

mk/platform.mk

@@ -26,10 +26,7 @@ endef
 $(foreach t,$(CFG_TARGET_TRIPLES),$(eval $(call DEF_OSTYPE_VAR,$(t))))
 $(foreach t,$(CFG_TARGET_TRIPLES),$(info cfg: os for $(t) is $(OSTYPE_$(t))))
 
-# FIXME: no-omit-frame-pointer is just so that task_start_wrapper
-# has a frame pointer and the stack walker can understand it. Turning off
-# frame pointers everywhere is overkill
-CFG_GCCISH_CFLAGS += -fno-omit-frame-pointer -DUSE_UTF8
+CFG_GCCISH_CFLAGS += -DUSE_UTF8
 
 # On Darwin, we need to run dsymutil so the debugging information ends
 # up in the right place.  On other platforms, it automatically gets
@@ -153,7 +150,6 @@ CFG_GCCISH_POST_LIB_FLAGS_x86_64-unknown-linux-gnu := -Wl,-no-whole-archive
 CFG_DEF_SUFFIX_x86_64-unknown-linux-gnu := .linux.def
 CFG_INSTALL_NAME_x86_64-unknown-linux-gnu =
 CFG_LIBUV_LINK_FLAGS_x86_64-unknown-linux-gnu =
-CFG_LLVM_BUILD_ENV_x86_64-unknown-linux-gnu="CXXFLAGS=-fno-omit-frame-pointer"
 CFG_EXE_SUFFIX_x86_64-unknown-linux-gnu =
 CFG_WINDOWSY_x86_64-unknown-linux-gnu :=
 CFG_UNIXY_x86_64-unknown-linux-gnu := 1
@@ -179,7 +175,6 @@ CFG_GCCISH_POST_LIB_FLAGS_i686-unknown-linux-gnu := -Wl,-no-whole-archive
 CFG_DEF_SUFFIX_i686-unknown-linux-gnu := .linux.def
 CFG_INSTALL_NAME_i686-unknown-linux-gnu =
 CFG_LIBUV_LINK_FLAGS_i686-unknown-linux-gnu =
-CFG_LLVM_BUILD_ENV_i686-unknown-linux-gnu="CXXFLAGS=-fno-omit-frame-pointer"
 CFG_EXE_SUFFIX_i686-unknown-linux-gnu =
 CFG_WINDOWSY_i686-unknown-linux-gnu :=
 CFG_UNIXY_i686-unknown-linux-gnu := 1

src/rustllvm/RustWrapper.cpp

@@ -342,7 +342,6 @@ LLVMRustBuildJIT(void* mem,
   std::string Err;
   TargetOptions Options;
   Options.JITEmitDebugInfo = true;
-  Options.NoFramePointerElim = true;
   Options.EnableSegmentedStacks = EnableSegmentedStacks;
   RustMCJITMemoryManager* MM = (RustMCJITMemoryManager*) mem;
   assert(MM);
@@ -393,7 +392,6 @@ LLVMRustWriteOutputFile(LLVMPassManagerRef PMR,
   }
 
   TargetOptions Options;
-  Options.NoFramePointerElim = true;
   Options.EnableSegmentedStacks = EnableSegmentedStacks;
   Options.FixedStackSegmentSize = 2 * 1024 * 1024;  // XXX: This is too big.