<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/124117>124117</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Build failure on Fedora Linux x86_64 due to missing llvm::StdThreadPool::asyncEnqueue(std::function<void ()>, llvm::ThreadPoolTaskGroup*)
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          vonbrand
      </td>
    </tr>
</table>

<pre>
    Fedora Linux rawhide, x86_64, up to date; llvmorg-20-init-18806-g19306351a2c4
The failure started around 2025-01-16.

Configured as:

cmake -G Ninja  -Wno-dev \
 -DCMAKE_BUILD_TYPE=Release \
 -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_FAST \
 -DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;lld;lldb;mlir;openmp;polly" \
  -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind;compiler-rt" \
 -DLLVM_USE_LINKER=gold \
  -DBUILD_SHARED_LIBS=ON \
 -DCMAKE_INSTALL_PREFIX=$HOME ../llvm

The build fails with:

FAILED: lib/libLLVMLTO.so.20.0git 
: && /usr/lib64/ccache/c++ -fPIC -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete -fuse-ld=gold   -Wl,--gc-sections -Wl,--dependency-file=lib/LTO/CMakeFiles/LLVMLTO.dir/link.d -shared -Wl,-soname,libLLVMLTO.so.20.0git -o lib/libLLVMLTO.so.20.0git lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o lib/LTO/CMakeFiles/LLVMLTO.dir/LTOBackend.cpp.o lib/LTO/CMakeFiles/LLVMLTO.dir/LTOModule.cpp.o lib/LTO/CMakeFiles/LLVMLTO.dir/LTOCodeGenerator.cpp.o lib/LTO/CMakeFiles/LLVMLTO.dir/UpdateCompilerUsed.cpp.o lib/LTO/CMakeFiles/LLVMLTO.dir/ThinLTOCodeGenerator.cpp.o -Wl,-rpath,"\$ORIGIN/../lib:/home/vonbrand/tmp/LLVM/llvm-project/build/lib:" lib/libLLVMExtensions.so.20.0git  lib/libPolly.so.20.0git lib/libLLVMPasses.so.20.0git  lib/libLLVMCodeGen.so.20.0git lib/libLLVMCGData.so.20.0git  lib/libLLVMCodeGenTypes.so.20.0git lib/libLLVMObjCARCOpts.so.20.0git  lib/libLLVMipo.so.20.0git lib/libLLVMBitWriter.so.20.0git  lib/libLLVMInstrumentation.so.20.0git lib/libLLVMLinker.so.20.0git  lib/libLLVMScalarOpts.so.20.0git lib/libLLVMAggressiveInstCombine.so.20.0git lib/libLLVMInstCombine.so.20.0git  lib/libLLVMTarget.so.20.0git lib/libPollyISL.so  lib/libLLVMTransformUtils.so.20.0git lib/libLLVMAnalysis.so.20.0git  lib/libLLVMObject.so.20.0git lib/libLLVMBitReader.so.20.0git  lib/libLLVMCore.so.20.0git lib/libLLVMRemarks.so.20.0git  lib/libLLVMMC.so.20.0git lib/libLLVMBinaryFormat.so.20.0git  lib/libLLVMTargetParser.so.20.0git lib/libLLVMSupport.so.20.0git -Wl,-rpath-link,/home/vonbrand/tmp/LLVM/llvm-project/build/lib && :
lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o:LTO.cpp:function (anonymous namespace)::WriteIndexesThinBackend::start(unsigned int, llvm::BitcodeModule, llvm::FunctionImporter::ImportMapTy const&, llvm::DenseSet<llvm::ValueInfo, llvm::DenseMapInfo<llvm::ValueInfo, void> > const&, std::map<unsigned long, llvm::GlobalValue::LinkageTypes, std::less<unsigned long>, std::allocator<std::pair<unsigned long const, llvm::GlobalValue::LinkageTypes> > > const&, llvm::MapVector<llvm::StringRef, llvm::BitcodeModule, llvm::DenseMap<llvm::StringRef, unsigned int, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, unsigned int> >, llvm::SmallVector<std::pair<llvm::StringRef, llvm::BitcodeModule>, 0u> >&):(.text._ZN12_GLOBAL__N_123WriteIndexesThinBackend5startEjN4llvm13BitcodeModuleERKNS1_16FunctionImporter11ImportMapTyERKNS1_8DenseSetINS1_9ValueInfoENS1_12DenseMapInfoIS8_vEEEERKSt3mapImNS1_11GlobalValue12LinkageTypesESt4lessImESaISt4pairIKmSG_EEERNS1_9MapVectorINS1_9StringRefES2_NS1_8DenseMapISR_jNS9_ISR_vEENS1_6detail12DenseMapPairISR_jEEEENS1_11SmallVectorISJ_ISR_S2_ELj0EEEEE+0x496): error: undefined reference to 'llvm::StdThreadPool::asyncEnqueue(std::function<void ()>, llvm::ThreadPoolTaskGroup*)'
collect2: error: ld returned 1 exit status

</pre>
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