<div dir="ltr">I can reliably reproduce the issue on linux with the following CMake command line:<div><br></div><div>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/<br></div><div><br></div><div><div>- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB</div><div>-- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB - Failed</div><div>-- Looking for __atomic_fetch_add_8 in atomic</div><div>-- Looking for __atomic_fetch_add_8 in atomic - not found</div><div>CMake Warning at projects/libcxx/cmake/Modules/CheckLibcxxAtomic.cmake:45 (message):</div><div>  Host compiler appears to require libatomic, but cannot find it.</div><div>Call Stack (most recent call first):</div><div>  projects/libcxx/cmake/config-ix.cmake:47 (include)</div><div>  projects/libcxx/CMakeLists.txt:370 (include)</div><div><br></div><div><br></div><div>-- Performing Test LIBCXX_HAS_WX_FLAG</div><div>-- Performing Test LIBCXX_HAS_WX_FLAG - Failed</div><div>-- Performing Test LIBCXX_HAS_NO_WX_FLAG</div><div>-- Performing Test LIBCXX_HAS_NO_WX_FLAG - Failed</div><div>-- Performing Test LIBCXX_HAS_EHSC_FLAG</div><div>-- Performing Test LIBCXX_HAS_EHSC_FLAG - Failed</div><div>-- Performing Test LIBCXX_HAS_NO_EHS_FLAG</div><div>-- Performing Test LIBCXX_HAS_NO_EHS_FLAG - Failed</div><div>-- Performing Test LIBCXX_HAS_NO_EHA_FLAG</div><div>-- Performing Test LIBCXX_HAS_NO_EHA_FLAG - Failed</div><div>-- Performing Test LIBCXX_HAS_NO_GR_FLAG</div><div>-- Performing Test LIBCXX_HAS_NO_GR_FLAG - Failed</div><div>-- Looking for pthread_create in pthread</div><div>-- Looking for pthread_create in pthread - not found</div><div>-- Looking for ccos in m</div><div>-- Looking for ccos in m - not found</div><div>-- Looking for clock_gettime in rt</div><div>-- Looking for clock_gettime in rt - not found</div><div>-- Performing Test LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG</div><div>-- Performing Test LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG - Failed</div><div>CMake Error at projects/libcxx/CMakeLists.txt:423 (message):</div><div>  C++11 or greater is required but the compiler does not support c++11</div><div><br></div><div><br></div><div>-- Configuring incomplete, errors occurred!</div><div>See also "/usr/local/google/home/aizatsky/out/llvm/fuzzer/CMakeFiles/CMakeOutput.log".</div><div>See also "/usr/local/google/home/aizatsky/out/llvm/fuzzer/CMakeFiles/CMakeError.log".</div><div>cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=OFF         23.14s user 12.73s system 100% cpu 35.826 total</div></div></div><br><div class="gmail_quote"><div dir="ltr">On Mon, Dec 12, 2016 at 11:10 AM Kostya Serebryany via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" class="gmail_msg">FTR, I've disabled libcxx checkout on that particular <a href="http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fuzzer" class="gmail_msg" target="_blank">bot</a> to make it green.<div class="gmail_msg">The problem remains, of course. :(</div></div><div class="gmail_extra gmail_msg"><br class="gmail_msg"><div class="gmail_quote gmail_msg">On Sun, Dec 11, 2016 at 7:23 AM, James Knight <span dir="ltr" class="gmail_msg"><<a href="mailto:jyknight@google.com" class="gmail_msg" target="_blank">jyknight@google.com</a>></span> wrote:<br class="gmail_msg"><blockquote class="gmail_quote gmail_msg" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="gmail_msg">On Dec 11, 2016, at 3:33 AM, Eric Fiselier via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="gmail_msg" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br class="gmail_msg">
> 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.<br class="gmail_msg">
><br class="gmail_msg">
> Can you confirm the bot has libatomic installed?<br class="gmail_msg">
<br class="gmail_msg">
</span>You shouldn't need it on x86-64. The issue there is that cmake is reporting, incorrectly:<br class="gmail_msg">
-- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB<br class="gmail_msg">
-- Performing Test LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB - Failed<br class="gmail_msg">
<br class="gmail_msg">
despite that previously in the same run, the same test configuring llvm itself worked:<br class="gmail_msg">
-- Performing Test HAVE_CXX_ATOMICS_WITHOUT_LIB<br class="gmail_msg">
-- Performing Test HAVE_CXX_ATOMICS_WITHOUT_LIB - Success<br class="gmail_msg">
<br class="gmail_msg">
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.</blockquote></div><br class="gmail_msg"></div>
_______________________________________________<br class="gmail_msg">
LLVM Developers mailing list<br class="gmail_msg">
<a href="mailto:llvm-dev@lists.llvm.org" class="gmail_msg" target="_blank">llvm-dev@lists.llvm.org</a><br class="gmail_msg">
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" rel="noreferrer" class="gmail_msg" target="_blank">http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><br class="gmail_msg">
</blockquote></div><div dir="ltr">-- <br></div><div data-smartmail="gmail_signature"><div dir="ltr">Mike<br>Sent from phone</div></div>