Seemingly false positives with MSAN and libc++ #100600
Description
I successfully built libc++ with msan parameters I thought but I seem to get some false positives in std::string class:
==49572==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x7ffff6cd4901 in std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator>::operator=(std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator> const&) /home/user/instrumentedlibcpp/llvm-project/msan_out/include/c++/v1/string:2531:11
libc++ built with:
cmake -GNinja ../runtimes
-DCMAKE_BUILD_TYPE=Release
-DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"
-DCMAKE_C_COMPILER=clang
-DCMAKE_CXX_COMPILER=clang++
-DBUILD_SHARED_LIBS="ON"
-DLLVM_USE_SANITIZER=MemoryWithOrigins
-DLIBCXXABI_USE_LLVM_UNWINDER=OFF
cmake --build . -- cxx cxxabi
llvmorg-18.1.8
The lib that calls this links against my libc++.so I checked.