[PATCH] D115907: [misexpect] Re-implement MisExpect Diagnostics

Thu Mar 31 14:51:19 PDT 2022

jgorbe added a comment.

Hi, this patch is causing floating point exceptions for us during profile generation. On a debug build I get this assertion failure (see stack trace below):

  clang: /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/BranchProbability.cpp:41: llvm::BranchProbability::BranchProbability(uint32_t, uint32_t): Assertion `Denominator > 0 && "Denominator cannot be 0!"' failed.

Printing some values around the problem I got

  TotalBranchWeight = 4294967296                   
  LikelyBranchWeight = 2147483648                                                                                                                                                                              
  UnlikelyBranchWeight = 2147483648                                                                                                                                                                            
  NumUnlikelyTargets = 1

I see the `BranchProbability` constructor takes `uint32_t`s, so this looks like it's overflowing to 0 (4294967296 is exactly 2**32).

I'm going to revert the patch to unbreak our build. Please let me know if you need more details and I'll try to come up with a reproducer I can share. Here's the stack trace for the assertion.

   #0 0x000000000a7f992a llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Unix/Signals.inc:565:11
   #1 0x000000000a7f9afb PrintStackTraceSignalHandler(void*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Unix/Signals.inc:632:1                                                                   
   #2 0x000000000a7f80bb llvm::sys::RunSignalHandlers() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Signals.cpp:102:5                                                                             
   #3 0x000000000a7fa271 SignalHandler(int) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Unix/Signals.inc:407:1                                                                                    
   #4 0x00007ff57cfe2200 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x13200)                                                                                                                          
   #5 0x00007ff57ca678a1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:50:1                                                                                                                                
   #6 0x00007ff57ca51546 abort ./stdlib/abort.c:81:7                                                                                                                                                           
   #7 0x00007ff57ca5142f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8                                                                                                                                    
   #8 0x00007ff57ca5142f _nl_load_domain ./intl/loadmsgcat.c:970:34                                                                                                                                            
   #9 0x00007ff57ca60222 (/lib/x86_64-linux-gnu/libc.so.6+0x35222)                                                                                                                                             
  #10 0x000000000a6cb517 llvm::BranchProbability::BranchProbability(unsigned int, unsigned int) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/BranchProbability.cpp:0:3                             
  #11 0x000000000a937a4d llvm::misexpect::verifyMisExpect(llvm::Instruction&, llvm::ArrayRef<unsigned int>, llvm::ArrayRef<unsigned int>) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/Utils/MisExpect.cpp:190:54                                                                                                                                                                                            
  #12 0x000000000a937ef3 llvm::misexpect::checkBackendInstrumentation(llvm::Instruction&, llvm::ArrayRef<unsigned int>) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/Utils/MisExpect.cpp:217:1  
  #13 0x000000000a93807b llvm::misexpect::checkExpectAnnotations(llvm::Instruction&, llvm::ArrayRef<unsigned int>, bool) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/Utils/MisExpect.cpp:236:1 
  #14 0x0000000009e1339c (anonymous namespace)::SampleProfileLoader::generateMDProfMetadata(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/IPO/SampleProfile.cpp:1755:19         
  #15 0x0000000009e10d94 (anonymous namespace)::SampleProfileLoader::emitAnnotations(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/IPO/SampleProfile.cpp:0:5                    
  #16 0x0000000009e1022b (anonymous namespace)::SampleProfileLoader::runOnFunction(llvm::Function&, llvm::AnalysisManager<llvm::Module>*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/IPO/SampleProfile.cpp:2199:5                                                                                                                                                                                          
  #17 0x0000000009e0ce8b (anonymous namespace)::SampleProfileLoader::runOnModule(llvm::Module&, llvm::AnalysisManager<llvm::Module>*, llvm::ProfileSummaryInfo*, llvm::CallGraph*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/IPO/SampleProfile.cpp:2113:15                                                                                                                                                
  #18 0x0000000009e0b882 llvm::SampleProfileLoaderPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Transforms/IPO/SampleProfile.cpp:2229:7
  #19 0x000000000c6e35c5 llvm::detail::PassModel<llvm::Module, llvm::SampleProfileLoaderPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/IR/PassManagerInternal.h:88:17
  #20 0x0000000009a7ee41 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module> >::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/IR/PassManager.h:522:16
  #21 0x000000000c5c9ae1 runNewPMPasses(llvm::lto::Config const&, llvm::Module&, llvm::TargetMachine*, unsigned int, bool, llvm::ModuleSummaryIndex*, llvm::ModuleSummaryIndex const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/LTO/LTOBackend.cpp:312:3
  #22 0x000000000c5c8cfe 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&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/LTO/LTOBackend.cpp:373:3
  #23 0x000000000c5cba45 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::Module&, llvm::ModuleSummaryIndex const&, llvm::StringMap<std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long> >, llvm::MallocAllocator> 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> >, std::vector<std::pair<llvm::StringRef, llvm::BitcodeModule>, std::allocator<std::pair<llvm::StringRef, llvm::BitcodeModule> > > >*, std::vector<unsigned char, std::allocator<unsigned char> > const&)::$_6::operator()(llvm::Module&, llvm::TargetMachine*, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile> >) const /usr/local/google/home/jgorbe/code/llvm/llvm/lib/LTO/LTOBackend.cpp:594:13
  #24 0x000000000c5cb971 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::Module&, llvm::ModuleSummaryIndex const&, llvm::StringMap<std::unordered_set<unsigned long, std::hash<unsigned long>, std::equal_to<unsigned long>, std::allocator<unsigned long> >, llvm::MallocAllocator> 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> >, std::vector<std::pair<llvm::StringRef, llvm::BitcodeModule>, std::allocator<std::pair<llvm::StringRef, llvm::BitcodeModule> > > >*, std::vector<unsigned char, std::allocator<unsigned char> > const&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/LTO/LTOBackend.cpp:670:3
  #25 0x000000000ad17e95 runThinLTOBackend(clang::DiagnosticsEngine&, llvm::ModuleSummaryIndex*, llvm::Module*, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, clang::BackendAction) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1670:11
  #26 0x000000000ad174c8 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1711:9
  #27 0x000000000bbd802f clang::CodeGenAction::ExecuteAction() /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:1209:3
  #28 0x000000000b9f1368 clang::FrontendAction::Execute() /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/FrontendAction.cpp:1036:7
  #29 0x000000000b9206ab clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/CompilerInstance.cpp:1036:23
  #30 0x000000000bbc34b9 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /usr/local/google/home/jgorbe/code/llvm/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:266:8
  #31 0x0000000006c0de77 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/cc1_main.cpp:248:13
  #32 0x0000000006c0076b ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:317:5
  #33 0x0000000006bff778 main /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:388:5
  #34 0x00007ff57ca527fd __libc_start_main ./csu/../csu/libc-start.c:332:16
  #35 0x0000000006bfef3a _start (/usr/local/google/home/jgorbe/code/llvm-build/bin/clang+0x6bfef3a)

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