[LLVMdev] compiler-rt CMake build ignores CMAKE_CXX_FLAGS

[Dmitri Gribenko]

Hello,

It looks like compiler-rt CMake scripts don't take CMAKE_CXX_FLAGS
into account.  This is because clang_compile and clang_link_shared
functions call the newly-built compiler directly, and they don't add
those flags.

Using CMAKE_CXX_FLAGS is necessary on systems where the C++11-enabled
libstdc++ is installed not in the default location.  For example, the
CentOS buildbot uses:

-DCMAKE_CXX_FLAGS=--gcc-toolchain=/opt/centos/devtoolset-1.1/root/usr

I tried adding ${CMAKE_CXX_FLAGS} to the compiler invocation in
clang_compile (with and without quotes), but in both cases the
resulting command is not correct, all of CMAKE_CXX_FLAGS is treated as
a single option, for example:

[6/67] Generating gtest-all.cc.x86_64.o
FAILED: cd /home/llvmbb/clang/build-cmake-r+a/projects/compiler-rt/lib/tsan/tests/unit
&& /home/llvmbb/clang/build-cmake-r+a/./bin/clang -fPIC -fno-builtin
-fno-exceptions -fomit-frame-pointer -funwind-tables
-fno-stack-protector -fvisibility=hidden -fno-function-sections -O3
-gline-tables-only -Wno-gnu -Wno-variadic-macros -Wno-c99-extensions
-Wno-non-virtual-dtor -fPIE -fno-rtti -DGTEST_NO_LLVM_RAW_OSTREAM=1
-I/home/llvmbb/clang/llvm/utils/unittest/googletest/include
-I/home/llvmbb/clang/llvm/utils/unittest/googletest
-I/home/llvmbb/clang/llvm/projects/compiler-rt/lib
-I/home/llvmbb/clang/llvm/projects/compiler-rt/lib/tsan/rtl -std=c++11
-DGTEST_HAS_RTTI=0
--gcc-toolchain=/opt/centos/devtoolset-1.1/root/usr\ -fPIC\
-fvisibility-inlines-hidden\ -Wall\ -W\ -Wno-unused-parameter\
-Wwrite-strings\ -Wmissing-field-initializers\ -pedantic\
-Wno-long-long\ -Wcovered-switch-default\ -Wnon-virtual-dtor\
-std=c++11\ -fcolor-diagnostics\ -ffunction-sections\ -fdata-sections\
-Wall\ -std=c++11 -m64 -c -o gtest-all.cc.x86_64.o
/home/llvmbb/clang/llvm/utils/unittest/googletest/src/gtest-all.cc

Note the backslases in the command.

Could maintainers of the compiler-rt CMake scripts help me with this?

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/