[llvm-dev] failing bootstrap: C++11 or greater is required but the compiler does not support c++11

[Mike Aizatsky via llvm-dev]

I can reliably reproduce the issue on linux with the following CMake
command line:

cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=OFF
-DLLVM_PARALLEL_LINK_JOBS=8
-DCMAKE_C_COMPILER=$HOME/out/llvm/bootstrap/bin/clang
-DCMAKE_CXX_COMPILER=$HOME/out/llvm/bootstrap/bin/clang++
-DLLVM_USE_SANITIZER=Address -DLLVM_USE_SANITIZE_COVERAGE=YES
-DLLVM_ENABLE_ASSERTIONS=ON ~/src/llvm/

- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB
-- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB - Failed
-- Looking for __atomic_fetch_add_8 in atomic
-- Looking for __atomic_fetch_add_8 in atomic - not found
CMake Warning at projects/libcxx/cmake/Modules/CheckLibcxxAtomic.cmake:45
(message):
  Host compiler appears to require libatomic, but cannot find it.
Call Stack (most recent call first):
  projects/libcxx/cmake/config-ix.cmake:47 (include)
  projects/libcxx/CMakeLists.txt:370 (include)


-- Performing Test LIBCXX_HAS_WX_FLAG
-- Performing Test LIBCXX_HAS_WX_FLAG - Failed
-- Performing Test LIBCXX_HAS_NO_WX_FLAG
-- Performing Test LIBCXX_HAS_NO_WX_FLAG - Failed
-- Performing Test LIBCXX_HAS_EHSC_FLAG
-- Performing Test LIBCXX_HAS_EHSC_FLAG - Failed
-- Performing Test LIBCXX_HAS_NO_EHS_FLAG
-- Performing Test LIBCXX_HAS_NO_EHS_FLAG - Failed
-- Performing Test LIBCXX_HAS_NO_EHA_FLAG
-- Performing Test LIBCXX_HAS_NO_EHA_FLAG - Failed
-- Performing Test LIBCXX_HAS_NO_GR_FLAG
-- Performing Test LIBCXX_HAS_NO_GR_FLAG - Failed
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - not found
-- Looking for ccos in m
-- Looking for ccos in m - not found
-- Looking for clock_gettime in rt
-- Looking for clock_gettime in rt - not found
-- Performing Test LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG
-- Performing Test LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG - Failed
CMake Error at projects/libcxx/CMakeLists.txt:423 (message):
  C++11 or greater is required but the compiler does not support c++11


-- Configuring incomplete, errors occurred!
See also
"/usr/local/google/home/aizatsky/out/llvm/fuzzer/CMakeFiles/CMakeOutput.log".
See also
"/usr/local/google/home/aizatsky/out/llvm/fuzzer/CMakeFiles/CMakeError.log".
cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=OFF
  23.14s user 12.73s system 100% cpu 35.826 total

On Mon, Dec 12, 2016 at 11:10 AM Kostya Serebryany via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> FTR, I've disabled libcxx checkout on that particular bot
> <http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fuzzer> to make
> it green.
> The problem remains, of course. :(
>
> On Sun, Dec 11, 2016 at 7:23 AM, James Knight <jyknight at google.com> wrote:
>
> On Dec 11, 2016, at 3:33 AM, Eric Fiselier via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
> > So it seems that libatomic went missing between build #1379 and #1380,
> so I don't think this is related to the -std=c++11 failure. Instead it
> seems likely that the compile test for -std=c++11 is failing due to
> mis-configuring -latomic.
> >
> > Can you confirm the bot has libatomic installed?
>
> You shouldn't need it on x86-64. The issue there is that cmake is
> reporting, incorrectly:
> -- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB
> -- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB - Failed
>
> despite that previously in the same run, the same test configuring llvm
> itself worked:
> -- Performing Test HAVE_CXX_ATOMICS_WITHOUT_LIB
> -- Performing Test HAVE_CXX_ATOMICS_WITHOUT_LIB - Success
>
> I suspect that the flags change has somehow caused *all* compiler
> invocations to fail, and that results in both the erroneously-failed atomic
> check and the erroneously-failed std=c++11 check.
>
>
> _______________________________________________
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>
-- 
Mike
Sent from phone
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