[LLVMdev] compiler-rt CMake build ignores CMAKE_CXX_FLAGS

[Alexey Samsonov]

Hi Dmitri,

On Sat, Mar 22, 2014 at 11:50 PM, Dmitri Gribenko <gribozavr at gmail.com>wrote:

> 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.
>

Indeed.


>
> 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:
>

Yes, recently I discovered the same problem and also though of adding
CMAKE_CXX_FLAGS
to manual clang invocations. I think it just needs to be done.


>
> [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.
>

Yep, because CMAKE_CXX_FLAGS is a string, and its contents is automatically
escaped when we use it in COMMAND in CMake rules. I guess we'll have to
manually
turn CMAKE_CXX_FLAGS into a CMake semicolon-separated list.


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

Thanks for the detailed description of your use case.
I will try to address this problem tomorrow.


>
> 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>*/
>

-- 
Alexey Samsonov, MSK
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