Segfault when using LTO

[mr-cheff]

Clang 18 segfaults when using thin LTO and PGO data. Please let me know if you need anything else

Logs:

02:23:45 143:44.96 PLEASE submit a bug report to [https://github.com/llvm/llvm-project/issues/](https://github.com/llvm/llvm-project/issues/?q=sort%3Aupdated-desc+is%3Aissue+is%3Aopen) and include the crash backtrace.
02:23:45 143:45.03  #0 0x00007f1d9abebb18 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x25ebb18)
02:23:45 143:45.03  #1 0x00007f1d9abebfec SignalHandler(int) Signals.cpp:0:0
02:23:45 143:45.03  #2 0x00007f1d97e42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
02:23:45 143:45.03  #3 0x00007f1d9a5c9570 llvm::slpvectorizer::BoUpSLP::vectorizeTree(llvm::slpvectorizer::BoUpSLP::TreeEntry*, bool) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1fc9570)
02:23:45 143:45.03  #4 0x00007f1d9a5c89dd llvm::slpvectorizer::BoUpSLP::vectorizeOperand(llvm::slpvectorizer::BoUpSLP::TreeEntry*, unsigned int, bool) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1fc89dd)
02:23:45 143:45.03  #5 0x00007f1d9a5ca0b7 llvm::slpvectorizer::BoUpSLP::vectorizeTree(llvm::slpvectorizer::BoUpSLP::TreeEntry*, bool) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1fca0b7)
02:23:45 143:45.03  #6 0x00007f1d9a42334a llvm::slpvectorizer::BoUpSLP::vectorizeTree(llvm::MapVector<llvm::Value*, llvm::SmallVector<llvm::Instruction*, 2u>, llvm::DenseMap<llvm::Value*, unsigned int, llvm::DenseMapInfo<llvm::Value*, void>, llvm::detail::DenseMapPair<llvm::Value*, unsigned int>>, llvm::SmallVector<std::pair<llvm::Value*, llvm::SmallVector<llvm::Instruction*, 2u>>, 0u>> const&, llvm::SmallVectorImpl<std::pair<llvm::Value*, llvm::Value*>>&, llvm::Instruction*) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1e2334a)
02:23:45 143:45.03  #7 0x00007f1d9a422694 llvm::slpvectorizer::BoUpSLP::vectorizeTree() (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1e22694)
02:23:45 143:45.03  #8 0x00007f1d9a451197 llvm::SLPVectorizerPass::tryToVectorizeList(llvm::ArrayRef<llvm::Value*>, llvm::slpvectorizer::BoUpSLP&, bool) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1e51197)
02:23:45 143:45.03  #9 0x00007f1d9a440b5c bool tryToVectorizeSequence<llvm::Value>(llvm::SmallVectorImpl<llvm::Value*>&, llvm::function_ref<bool (llvm::Value*, llvm::Value*)>, llvm::function_ref<bool (llvm::Value*, llvm::Value*)>, llvm::function_ref<bool (llvm::ArrayRef<llvm::Value*>, bool)>, bool, llvm::slpvectorizer::BoUpSLP&) SLPVectorizer.cpp:0:0
02:23:45 143:45.03 #10 0x00007f1d9a449e8f llvm::SLPVectorizerPass::vectorizeChainsInBlock(llvm::BasicBlock*, llvm::slpvectorizer::BoUpSLP&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1e49e8f)
02:23:45 143:45.03 #11 0x00007f1d9a445570 llvm::SLPVectorizerPass::runImpl(llvm::Function&, llvm::ScalarEvolution*, llvm::TargetTransformInfo*, llvm::TargetLibraryInfo*, llvm::AAResults*, llvm::LoopInfo*, llvm::DominatorTree*, llvm::AssumptionCache*, llvm::DemandedBits*, llvm::OptimizationRemarkEmitter*) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1e45570)
02:23:45 143:45.03 #12 0x00007f1d9a444451 llvm::SLPVectorizerPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1e44451)
02:23:45 143:45.03 #13 0x00007f1d9a44424d llvm::detail::PassModel<llvm::Function, llvm::SLPVectorizerPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) PassBuilder.cpp:0:0
02:23:45 143:45.03 #14 0x00007f1d9a010bbd llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1a10bbd)
02:23:45 143:45.03 #15 0x00007f1d9a01088d llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) X86CodeGenPassBuilder.cpp:0:0
02:23:45 143:45.03 #16 0x00007f1d9a01f816 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x1a1f816)
02:23:45 143:45.03 #17 0x00007f1d9a01f44d llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) X86CodeGenPassBuilder.cpp:0:0
02:23:45 143:45.03 #18 0x00007f1d9a82d3a1 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x222d3a1)
02:23:45 143:45.03 #19 0x00007f1d9b8790ed llvm::lto::opt(llvm::lto::Config const&, llvm::TargetMachine*, unsigned int, llvm::Module&, bool, llvm::ModuleSummaryIndex*, llvm::ModuleSummaryIndex const*, std::vector<unsigned char, std::allocator<unsigned char>> const&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x32790ed)
02:23:45 143:45.04 #20 0x00007f1d9b87cad2 llvm::lto::thinBackend(llvm::lto::Config const&, unsigned int, std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream, std::default_delete<llvm::CachedFileStream>>> (unsigned int, llvm::Twine const&)>, llvm::Module&, llvm::ModuleSummaryIndex const&, llvm::DenseMap<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>>> const&, llvm::DenseMap<unsigned long, llvm::GlobalValueSummary*, llvm::DenseMapInfo<unsigned long, void>, llvm::detail::DenseMapPair<unsigned long, llvm::GlobalValueSummary*>> 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>>*, std::vector<unsigned char, std::allocator<unsigned char>> const&)::$_0::operator()(llvm::Module&, llvm::TargetMachine*, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>) const LTOBackend.cpp:0:0
02:23:45 143:45.04 #21 0x00007f1d9b87c96a llvm::lto::thinBackend(llvm::lto::Config const&, unsigned int, std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream, std::default_delete<llvm::CachedFileStream>>> (unsigned int, llvm::Twine const&)>, llvm::Module&, llvm::ModuleSummaryIndex const&, llvm::DenseMap<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>>> const&, llvm::DenseMap<unsigned long, llvm::GlobalValueSummary*, llvm::DenseMapInfo<unsigned long, void>, llvm::detail::DenseMapPair<unsigned long, llvm::GlobalValueSummary*>> 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>>*, std::vector<unsigned char, std::allocator<unsigned char>> const&) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x327c96a)
02:23:45 143:45.04 #22 0x00007f1d9b875b9c (anonymous namespace)::InProcessThinBackend::runThinLTOBackendThread(std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream, std::default_delete<llvm::CachedFileStream>>> (unsigned int, llvm::Twine const&)>, std::function<llvm::Expected<std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream, std::default_delete<llvm::CachedFileStream>>> (unsigned int, llvm::Twine const&)>> (unsigned int, llvm::StringRef, llvm::Twine const&)>, unsigned int, llvm::BitcodeModule, llvm::ModuleSummaryIndex&, llvm::DenseMap<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>>> 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::DenseMap<unsigned long, llvm::GlobalValueSummary*, llvm::DenseMapInfo<unsigned long, void>, llvm::detail::DenseMapPair<unsigned long, llvm::GlobalValueSummary*>> 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>>&)::'lambda'(std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream, std::default_delete<llvm::CachedFileStream>>> (unsigned int, llvm::Twine const&)>)::operator()(std::function<llvm::Expected<std::unique_ptr<llvm::CachedFileStream, std::default_delete<llvm::CachedFileStream>>> (unsigned int, llvm::Twine const&)>) const LTO.cpp:0:0
02:23:45 143:45.04 #23 0x00007f1d9b875619 std::_Function_handler<void (), std::_Bind<(anonymous namespace)::InProcessThinBackend::start(unsigned int, llvm::BitcodeModule, llvm::DenseMap<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>>> 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>>&)::'lambda'(llvm::BitcodeModule, llvm::ModuleSummaryIndex&, llvm::DenseMap<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>>> 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::DenseMap<unsigned long, llvm::GlobalValueSummary*, llvm::DenseMapInfo<unsigned long, void>, llvm::detail::DenseMapPair<unsigned long, llvm::GlobalValueSummary*>> 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>>&) (llvm::BitcodeModule, std::reference_wrapper<llvm::ModuleSummaryIndex>, std::reference_wrapper<llvm::DenseMap<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>, llvm::DenseMapInfo<llvm::StringRef, void>, llvm::detail::DenseMapPair<llvm::StringRef, std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long>>>> const>, std::reference_wrapper<llvm::DenseSet<llvm::ValueInfo, llvm::DenseMapInfo<llvm::ValueInfo, void>> const>, std::reference_wrapper<std::map<unsigned long, llvm::GlobalValue::LinkageTypes, std::less<unsigned long>, std::allocator<std::pair<unsigned long const, llvm::GlobalValue::LinkageTypes>>> const>, std::reference_wrapper<llvm::DenseMap<unsigned long, llvm::GlobalValueSummary*, llvm::DenseMapInfo<unsigned long, void>, llvm::detail::DenseMapPair<unsigned long, llvm::GlobalValueSummary*>> const>, std::reference_wrapper<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>>>)>>::_M_invoke(std::_Any_data const&) LTO.cpp:0:0
02:23:45 143:45.04 #24 0x00007f1d9ab4ced2 std::_Function_handler<void (), llvm::ThreadPool::createTaskAndFuture(std::function<void ()>)::'lambda'()>::_M_invoke(std::_Any_data const&) BalancedPartitioning.cpp:0:0
02:23:45 143:45.04 #25 0x00007f1d9abac723 llvm::ThreadPool::processTasks(llvm::ThreadPoolTaskGroup*) (/home/runner/.mozbuild/clang/bin/../lib/libLLVM.so.18.1+0x25ac723)
02:23:45 143:45.04 #26 0x00007f1d9abad15e void* llvm::thread::ThreadProxy<std::tuple<llvm::ThreadPool::grow(int)::$_0>>(void*) ThreadPool.cpp:0:0
02:23:45 143:45.04 #27 0x00007f1d97e94ac3 (/lib/x86_64-linux-gnu/libc.so.6+0x94ac3)
02:23:45 143:45.04 #28 0x00007f1d97f26850 (/lib/x86_64-linux-gnu/libc.so.6+0x126850)
02:23:57 143:56.82 clang++: error: unable to execute command: Segmentation fault (core dumped)
02:23:57 143:56.82 clang++: error: linker command failed due to signal (use -v to see invocation)

[fhahn]

To reproduce we need the inputs that is causing the crash. You could try passing -save-temps to generate the IR before LTO runs (exact flags depend on what linker you are using on what platform)

Also, there won't be another 18.x release I think. Please try if this still reproduces on current main (or 19.x)

[EugeneZelenko]

Could you please try 19 or main branch?

[alexey-bataev]

I think, this is a duplicate of several other reports, which do not reproduce with 19 and trunk