[DebugInfo] Only create concrete DIEs of concrete functions

[ellis]

Summary

At the begining of the module we can iterate through the functions to
see which SPs should have concrete DIEs. Then when we need to reference
a DIE for a SP we can decide if it's ok to create a concrete DIE or not.

Fixes

• https://bugs.llvm.org/show_bug.cgi?id=52159
• https://bugs.llvm.org/show_bug.cgi?id=30637

[ellis]

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

324–329

I just realized that maintaining both ProcessedSPNodes and ConcreteSPs is not necessary. If this gets accepted I'll remove ProcessedSPNodes.

[dblaikie]

Oh, this sounds good - with the followup cleanup as you mentioned. Thanks for working through all this!

[ellis]

@dblaikie Turns out that since outlined machine functions are created during codegen, we can't see that those SPs are concrete during beginModule(). I've left ProcessedSPNodes how it was (which does include outlined SPs) and added comments to ConcreteSPs.

[ellis]

Could I get another quick review from these changes?

[dblaikie]

In D112337#3103579, @ellis wrote:

@dblaikie Turns out that since outlined machine functions are created during codegen, we can't see that those SPs are concrete during beginModule(). I've left ProcessedSPNodes how it was (which does include outlined SPs) and added comments to ConcreteSPs.

Does that not cause problems for the strategy in general? Wouldn't this mean new concrete subprograms would show up and break the assumptions made that only ConcreteSPs are the ones that need to be separated from the abstract definition?

[ellis]

In D112337#3103673, @dblaikie wrote:

In D112337#3103579, @ellis wrote:

@dblaikie Turns out that since outlined machine functions are created during codegen, we can't see that those SPs are concrete during beginModule(). I've left ProcessedSPNodes how it was (which does include outlined SPs) and added comments to ConcreteSPs.

Does that not cause problems for the strategy in general? Wouldn't this mean new concrete subprograms would show up and break the assumptions made that only ConcreteSPs are the ones that need to be separated from the abstract definition?

Machine outlined subprograms won't be inlined so they won't ever have an abstract origin. For SPs that aren't found in getAbstractSPDies() (constructAbstractSubprogramScopeDIE() is never called for them), this diff is a no-op.

Maybe ConcreteSPs is a bad name now. I guess now it only holds SPs that are concrete and could possibly be inlined (have an abstract origin)

[ellis]

@dblaikie Let me know if you have any concerns. The machine outliner only creates an SP that won't be the scope of any other DI element because the machine outliner does not copy any debug info.

[dblaikie]

Sure - let's go with it. (the "IsConcrete" function still might be nice to have a more precise name - but I don't have any good suggestions off-hand)

[thakis]

Looks like this breaks check-llvm on mac and windows:
http://45.33.8.238/mac/38516/step_11.txt
http://45.33.8.238/win/48589/step_11.txt

Please take a look and revert for now if it takes a while to fix.

[ellis]

In D112337#3119393, @thakis wrote:

Looks like this breaks check-llvm on mac and windows:
http://45.33.8.238/mac/38516/step_11.txt
http://45.33.8.238/win/48589/step_11.txt

Please take a look and revert for now if it takes a while to fix.

Apologies, I believe https://reviews.llvm.org/D113506 should fix the inlined-static-var.ll test, but I'm not sure about the others.

[akuegel]

We have isolated this patch to cause a crash when compiling certain source files. My colleague has created a minimized reproducer, which I will share below, however I must note that personally I could not reproduce the crash with that reproducer. However I verified that with this patch reverted, we don't run into the crash anymore when compiling the original source file.

class A {
public:

unsigned n;                                                     
void Append() {                                                     
  auto raw_append = [] {};                                                     
  while (Avail())                                                     
    ;
}                                                     
long Avail();

} a;
bool c;
void f(A) { a.Append(); }

Crashes with

~/code/llvm-build-release/bin/clang "-cc1" "-triple" "x86_64-grtev4-linux-gnu" -ferror-limit 9999 "-emit-obj" "-debug-info-kind=constructor" "-dwarf-version=5" "-mllvm" "-generate-type-units" "-O3" "-std=gnu++17" "-fgnuc-version=4.2.1" "-fsized-deallocation" "-mllvm" "-disable-binop-extract-shuffle" "-x" "c++" "repro.ii"

[akuegel]

So unfortunately I was not able to create a standalone reproducer, but the crash happened when compiling the cord_internal target from Abseil with a clang build which includes your patch:

https://github.com/abseil/abseil-cpp/blob/master/absl/strings/BUILD.bazel#L268

The stack trace looks like this:

#0 0x000055c3d0823d78 llvm::sys::RunSignalHandlers()
#1 0x000055c3d08263ac SignalHandler(int)
#2 0x00007f738ab60750 restore_rt
#3 0x000055c3cf433a35 llvm::DIE::computeOffsetsAndAbbrevs(llvm::AsmPrinter const*, llvm::DIEAbbrevSet&, unsigned int)
#4 0x000055c3cf433a56 llvm::DIE::computeOffsetsAndAbbrevs(llvm::AsmPrinter const*, llvm::DIEAbbrevSet&, unsigned int)
#5 0x000055c3cf433a56 llvm::DIE::computeOffsetsAndAbbrevs(llvm::AsmPrinter const*, llvm::DIEAbbrevSet&, unsigned int)
#6 0x000055c3cf47086f llvm::DwarfFile::computeSizeAndOffsets()
#7 0x000055c3cf4421e8 llvm::DwarfDebug::finalizeModuleInfo()
#8 0x000055c3cf4422c0 llvm::DwarfDebug::endModule()
#9 0x000055c3cf40d81c llvm::AsmPrinter::doFinalization(llvm::Module&)
#10 0x000055c3d06ffda1 llvm::FPPassManager::doFinalization(llvm::Module&)
#11 0x000055c3d06f9dc2 llvm::legacy::PassManagerImpl::run(llvm::Module&)
#12 0x000055c3ccbdb248 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::u::unique_ptr<llvm::raw_pwrite_stream, std::__u::default_delete<llvm::raw_pwrite_stream> >)
#13 0x000055c3ccbd6eb3 clang::CodeGenAction::ExecuteAction()
#14 0x000055c3cd4c0e7a clang::FrontendAction::Execute()
#15 0x000055c3cd439676 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
#16 0x000055c3cc8da5a6 clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
#17 0x000055c3cc8cf131 cc1_main(llvm::ArrayRef<char const*>, char const*, void*)
#18 0x000055c3cc8cd4c2 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&)
#19 0x000055c3cc8cd2bf main

[jgorbe]

Hi, I created the reproducer that akuegel posted above. I have reproduced the crash starting with a clean repo with the steps below. The stack trace is a bit different, but a release build following the same steps will get you a stack trace very similar to what he posted. What I've noticed is that the crash does not always reproduce consistently. I was trying a new release build to double check the steps below, I ran the build command multiple times in a row, and it crashed only sometimes. The crash is a segfault, so it's possible that sometimes an invalid memory access doesn't immediatly crash the program.

$ git checkout f19471a24985a0cbc32b6548c8fce1d2514e8243
$ mkdir ../llvm-new-build
$ cd ../llvm-new-build
$ cmake -GNinja -DCMAKE_BUILD_TYPE=Debug -DLLVM_ENABLE_PROJECTS="clang;lld" -DCMAKE_C_COMPILER=clang-11 -DCMAKE_CXX_COMPILER=clang++-11 -DCMAKE_ASM_COMPILER=clang-11 -DLLVM_ENABLE_LLD=ON ../llvm/llvm
$ ninja
$ cat > repro.ii                                                                                                                
class A {
public:
  unsigned n;
  void Append() {
    auto raw_append = [] {};
    while (Avail())
      ;
  }
  long Avail();
} a;
bool c;
void f(A) { a.Append(); }
$ bin/clang "-cc1" "-triple" "x86_64-grtev4-linux-gnu" -ferror-limit 9999 "-emit-obj" "-debug-info-kind=constructor" "-dwarf-version=5" "-mllvm" "-generate-type-units" "-O3" "-std=gnu++17" "-fgnuc-version=4.2.1" "-fsized-deallocation" "-mllvm" "-disable-binop-extract-shuffle" "-x" "c++" "repro.ii"
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: bin/clang -cc1 -triple x86_64-grtev4-linux-gnu -ferror-limit 9999 -emit-obj -debug-info-kind=constructor -dwarf-version=5 -mllvm -generate-type-units -O3 -std=gnu++17 -fgnuc-version=4.2.1 -fsized-deallocation -mllvm -disable-binop-extract-shuffle -x c++ repro.ii
1.	<eof> parser at end of file
2.	Code generation
 #0 0x000000000a1f60ea llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Unix/Signals.inc:565:11
 #1 0x000000000a1f62bb PrintStackTraceSignalHandler(void*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Unix/Signals.inc:632:1
 #2 0x000000000a1f489b llvm::sys::RunSignalHandlers() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Signals.cpp:96:5
 #3 0x000000000a1f6a31 SignalHandler(int) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Support/Unix/Signals.inc:407:1
 #4 0x00007fb0702ab8e0 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x138e0)
 #5 0x000000000b9354b0 llvm::PointerIntPair<llvm::IntrusiveBackListNode*, 1u, unsigned int, llvm::PointerLikeTypeTraits<llvm::IntrusiveBackListNode*>, llvm::PointerIntPairInfo<llvm::IntrusiveBackListNode*, 1u, llvm::PointerLikeTypeTraits<llvm::IntrusiveBackListNode*> > >::getPointer() const /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/ADT/PointerIntPair.h:59:58
 #6 0x000000000b93544a llvm::IntrusiveBackList<llvm::DIEValueList::Node>::begin() /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:635:19
 #7 0x000000000b935335 llvm::IntrusiveBackList<llvm::DIEValueList::Node>::begin() const /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:638:51
 #8 0x000000000b934f2c llvm::DIEValueList::values() const /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:731:49
 #9 0x000000000b934aca llvm::AsmPrinter::emitDwarfDIE(llvm::DIE const&) const /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp:293:28
#10 0x000000000b934d8f llvm::AsmPrinter::emitDwarfDIE(llvm::DIE const&) const /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp:310:22
#11 0x000000000b934d8f llvm::AsmPrinter::emitDwarfDIE(llvm::DIE const&) const /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp:310:22
#12 0x000000000b9f0b92 llvm::DwarfFile::emitUnit(llvm::DwarfUnit*, bool) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp:54:28
#13 0x000000000b9f0a6e llvm::DwarfFile::emitUnits(bool) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp:32:25
#14 0x000000000b95c5ad llvm::DwarfDebug::emitDebugInfo() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:2291:1
#15 0x000000000b95c06c llvm::DwarfDebug::endModule() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:1443:3
#16 0x000000000b917c5c llvm::AsmPrinter::doFinalization(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp:1839:3
#17 0x000000000949cc8a llvm::FPPassManager::doFinalization(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1503:16
#18 0x0000000009498494 (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1590:16
#19 0x0000000009497cd8 llvm::legacy::PassManagerImpl::run(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:542:16
#20 0x000000000949ce61 llvm::legacy::PassManager::run(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1681:3
#21 0x000000000a6ba76f (anonymous namespace)::EmitAssemblyHelper::RunCodegenPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile> >&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1502:1
#22 0x000000000a6b2962 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(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:1533:7
#23 0x000000000a6b1124 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:1693:5
#24 0x000000000b4a146b clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:370:7
#25 0x000000000dceeeee clang::ParseAST(clang::Sema&, bool, bool) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Parse/ParseAST.cpp:178:12
#26 0x000000000b2bac72 clang::ASTFrontendAction::ExecuteAction() /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/FrontendAction.cpp:1076:1
#27 0x000000000b49cb0b clang::CodeGenAction::ExecuteAction() /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:1108:5
#28 0x000000000b2ba638 clang::FrontendAction::Execute() /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/FrontendAction.cpp:971:7
#29 0x000000000b1ee852 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/CompilerInstance.cpp:1030:23
#30 0x000000000b4897c9 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /usr/local/google/home/jgorbe/code/llvm/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:261:8
#31 0x000000000681bd7d cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/cc1_main.cpp:246:13
#32 0x000000000680e678 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:317:5
#33 0x000000000680d692 main /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:388:5
#34 0x00007fb06fd30e4a __libc_start_main ./csu/../csu/libc-start.c:314:16
#35 0x000000000680ceba _start (bin/clang+0x680ceba)

[jgorbe]

I rebuilt clang at this commit with -DLLVM_USE_SANITIZER=Address and it reports a problem nearby. I don't know if this patch is the actual root cause for the crash or if it's triggering an existing bug. Here's the full report in case it can help you debug the issue further:

=================================================================
==65688==ERROR: AddressSanitizer: heap-use-after-free on address 0x621000114780 at pc 0x00000d6d07eb bp 0x7ffe39a2fcd0 sp 0x7ffe39a2fcc8
READ of size 8 at 0x621000114780 thread T0
    #0 0xd6d07ea in push_back /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:537:14
    #1 0xd6d07ea in push_back /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:560:49
    #2 0xd6d07ea in addChild /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:849:14
    #3 0xd6d07ea in createAndAddScopeChildren /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1088:14
    #4 0xd6d07ea in llvm::DwarfCompileUnit::constructAbstractSubprogramScopeDIE(llvm::LexicalScope*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1134:39
    #5 0xd66fd55 in llvm::DwarfDebug::endFunctionImpl(llvm::MachineFunction const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:2251:5
    #6 0xd622f12 in llvm::DebugHandlerBase::endFunction(llvm::MachineFunction const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp:410:5
    #7 0xd5e37bc in llvm::AsmPrinter::emitFunctionBody() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp:1505:17
    #8 0x71988ca in llvm::X86AsmPrinter::runOnMachineFunction(llvm::MachineFunction&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Target/X86/X86AsmPrinter.cpp:82:3
    #9 0x871b761 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/MachineFunctionPass.cpp:72:13
    #10 0x93e2a5f in llvm::FPPassManager::runOnFunction(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1439:27
    #11 0x93f6582 in llvm::FPPassManager::runOnModule(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1485:16
    #12 0x93e3adb in runOnModule /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1554:27
    #13 0x93e3adb in llvm::legacy::PassManagerImpl::run(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:542:44
    #14 0xb459526 in RunCodegenPipeline /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1501:17
    #15 0xb459526 in EmitAssembly /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1531:3
    #16 0xb459526 in 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:1693:15
    #17 0xccd1b86 in clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:370:7
    #18 0xfeeba7d in clang::ParseAST(clang::Sema&, bool, bool) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Parse/ParseAST.cpp:171:13
    #19 0xcccc3a0 in clang::CodeGenAction::ExecuteAction() /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:1107:30
    #20 0xca60cf5 in clang::FrontendAction::Execute() /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/FrontendAction.cpp:967:8
    #21 0xc874011 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/CompilerInstance.cpp:1030:33
    #22 0xccbc008 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /usr/local/google/home/jgorbe/code/llvm/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:261:25
    #23 0x41b8a70 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/cc1_main.cpp:246:15
    #24 0x41b3db9 in ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:317:12
    #25 0x41b22a7 in main /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:388:12
    #26 0x7f9bd7d73e49 in __libc_start_main csu/../csu/libc-start.c:314:16
    #27 0x40ff079 in _start (/usr/local/google/home/jgorbe/code/llvm-new-build/bin/clang-14+0x40ff079)

0x621000114780 is located 640 bytes inside of 4096-byte region [0x621000114500,0x621000115500)
freed by thread T0 here:
    #0 0x41a926d in operator delete(void*) (/usr/local/google/home/jgorbe/code/llvm-new-build/bin/clang-14+0x41a926d)
    #1 0x41b5a9f in Deallocate /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/AllocatorBase.h:92:5
    #2 0x41b5a9f in DeallocateSlabs /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/Allocator.h:351:19
    #3 0x41b5a9f in llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, 4096ul, 4096ul, 128ul>::~BumpPtrAllocatorImpl() /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/Allocator.h:100:5
    #4 0xd6817fc in operator() /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/unique_ptr.h:85:2
    #5 0xd6817fc in ~unique_ptr /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/unique_ptr.h:361:4
    #6 0xd6817fc in ~pair /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/stl_pair.h:211:12
    #7 0xd6817fc in destroy_range /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/ADT/SmallVector.h:327:11
    #8 0xd6817fc in ~SmallVector /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/ADT/SmallVector.h:1175:5
    #9 0xd6817fc in llvm::DwarfDebug::addDwarfTypeUnitType(llvm::DwarfCompileUnit&, llvm::StringRef, llvm::DIE&, llvm::DICompositeType const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:3440:3
    #10 0xd72e9a8 in llvm::DwarfUnit::createTypeDIE(llvm::DIScope const*, llvm::DIE&, llvm::DIType const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:587:13
    #11 0xd72952a in llvm::DwarfUnit::addType(llvm::DIE&, llvm::DIType const*, llvm::dwarf::Attribute) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:650:44
    #12 0xd6cd5df in llvm::DwarfCompileUnit::applyVariableAttributes(llvm::DbgVariable const&, llvm::DIE&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1526:3
    #13 0xd6cad65 in llvm::DwarfCompileUnit::constructVariableDIEImpl(llvm::DbgVariable const&, bool) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:735:5
    #14 0xd6c6ccb in constructVariableDIE /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:711:12
    #15 0xd6c6ccb in constructVariableDIE /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:907:14
    #16 0xd6c6ccb in llvm::DwarfCompileUnit::createScopeChildrenDIE(llvm::LexicalScope*, llvm::SmallVectorImpl<llvm::DIE*>&, bool*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1030:24
    #17 0xd6d02d9 in createAndAddScopeChildren /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1084:24
    #18 0xd6d02d9 in llvm::DwarfCompileUnit::constructAbstractSubprogramScopeDIE(llvm::LexicalScope*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1134:39
    #19 0xd66fd55 in llvm::DwarfDebug::endFunctionImpl(llvm::MachineFunction const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:2251:5
    #20 0xd622f12 in llvm::DebugHandlerBase::endFunction(llvm::MachineFunction const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp:410:5
    #21 0xd5e37bc in llvm::AsmPrinter::emitFunctionBody() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp:1505:17
    #22 0x71988ca in llvm::X86AsmPrinter::runOnMachineFunction(llvm::MachineFunction&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Target/X86/X86AsmPrinter.cpp:82:3
    #23 0x871b761 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/MachineFunctionPass.cpp:72:13
    #24 0x93e2a5f in llvm::FPPassManager::runOnFunction(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1439:27
    #25 0x93f6582 in llvm::FPPassManager::runOnModule(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1485:16
    #26 0x93e3adb in runOnModule /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1554:27
    #27 0x93e3adb in llvm::legacy::PassManagerImpl::run(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:542:44
    #28 0xb459526 in RunCodegenPipeline /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1501:17
    #29 0xb459526 in EmitAssembly /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1531:3
    #30 0xb459526 in 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:1693:15
    #31 0xccd1b86 in clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:370:7
    #32 0xfeeba7d in clang::ParseAST(clang::Sema&, bool, bool) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Parse/ParseAST.cpp:171:13
    #33 0xcccc3a0 in clang::CodeGenAction::ExecuteAction() /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:1107:30
    #34 0xca60cf5 in clang::FrontendAction::Execute() /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/FrontendAction.cpp:967:8
    #35 0xc874011 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/CompilerInstance.cpp:1030:33
    #36 0xccbc008 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /usr/local/google/home/jgorbe/code/llvm/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:261:25
    #37 0x41b8a70 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/cc1_main.cpp:246:15
    #38 0x41b3db9 in ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:317:12
    #39 0x41b22a7 in main /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:388:12
    #40 0x7f9bd7d73e49 in __libc_start_main csu/../csu/libc-start.c:314:16

previously allocated by thread T0 here:
    #0 0x41a8a0d in operator new(unsigned long) (/usr/local/google/home/jgorbe/code/llvm-new-build/bin/clang-14+0x41a8a0d)
    #1 0x41f8aac in Allocate /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/AllocatorBase.h:85:12
    #2 0x41f8aac in StartNewSlab /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/Allocator.h:335:21
    #3 0x41f8aac in llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, 4096ul, 4096ul, 128ul>::Allocate(unsigned long, llvm::Align) /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/Allocator.h:190:5
    #4 0xd6d9601 in Allocate /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/Allocator.h:204:12
    #5 0xd6d9601 in operator new<llvm::MallocAllocator, 4096, 4096, 128> /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/Support/Allocator.h:437:20
    #6 0xd6d9601 in llvm::DIEValueList::addValue(llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, 4096ul, 4096ul, 128ul>&, llvm::DIEValue const&) /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:714:21
    #7 0xd722662 in addAttribute<llvm::DIEInteger> /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h:92:9
    #8 0xd722662 in llvm::DwarfUnit::addUInt(llvm::DIEValueList&, llvm::dwarf::Attribute, llvm::Optional<llvm::dwarf::Form>, unsigned long) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:234:3
    #9 0xd68103c in llvm::DwarfDebug::addDwarfTypeUnitType(llvm::DwarfCompileUnit&, llvm::StringRef, llvm::DIE&, llvm::DICompositeType const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:3382:9
    #10 0xd72e9a8 in llvm::DwarfUnit::createTypeDIE(llvm::DIScope const*, llvm::DIE&, llvm::DIType const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:587:13
    #11 0xd72952a in llvm::DwarfUnit::addType(llvm::DIE&, llvm::DIType const*, llvm::dwarf::Attribute) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:650:44
    #12 0xd6cd5df in llvm::DwarfCompileUnit::applyVariableAttributes(llvm::DbgVariable const&, llvm::DIE&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1526:3
    #13 0xd6cad65 in llvm::DwarfCompileUnit::constructVariableDIEImpl(llvm::DbgVariable const&, bool) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:735:5
    #14 0xd6c6ccb in constructVariableDIE /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:711:12
    #15 0xd6c6ccb in constructVariableDIE /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:907:14
    #16 0xd6c6ccb in llvm::DwarfCompileUnit::createScopeChildrenDIE(llvm::LexicalScope*, llvm::SmallVectorImpl<llvm::DIE*>&, bool*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1030:24
    #17 0xd6d02d9 in createAndAddScopeChildren /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1084:24
    #18 0xd6d02d9 in llvm::DwarfCompileUnit::constructAbstractSubprogramScopeDIE(llvm::LexicalScope*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:1134:39
    #19 0xd66fd55 in llvm::DwarfDebug::endFunctionImpl(llvm::MachineFunction const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp:2251:5
    #20 0xd622f12 in llvm::DebugHandlerBase::endFunction(llvm::MachineFunction const*) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp:410:5
    #21 0xd5e37bc in llvm::AsmPrinter::emitFunctionBody() /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp:1505:17
    #22 0x71988ca in llvm::X86AsmPrinter::runOnMachineFunction(llvm::MachineFunction&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/Target/X86/X86AsmPrinter.cpp:82:3
    #23 0x871b761 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/CodeGen/MachineFunctionPass.cpp:72:13
    #24 0x93e2a5f in llvm::FPPassManager::runOnFunction(llvm::Function&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1439:27
    #25 0x93f6582 in llvm::FPPassManager::runOnModule(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1485:16
    #26 0x93e3adb in runOnModule /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:1554:27
    #27 0x93e3adb in llvm::legacy::PassManagerImpl::run(llvm::Module&) /usr/local/google/home/jgorbe/code/llvm/llvm/lib/IR/LegacyPassManager.cpp:542:44
    #28 0xb459526 in RunCodegenPipeline /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1501:17
    #29 0xb459526 in EmitAssembly /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/BackendUtil.cpp:1531:3
    #30 0xb459526 in 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:1693:15
    #31 0xccd1b86 in clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:370:7
    #32 0xfeeba7d in clang::ParseAST(clang::Sema&, bool, bool) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Parse/ParseAST.cpp:171:13
    #33 0xcccc3a0 in clang::CodeGenAction::ExecuteAction() /usr/local/google/home/jgorbe/code/llvm/clang/lib/CodeGen/CodeGenAction.cpp:1107:30
    #34 0xca60cf5 in clang::FrontendAction::Execute() /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/FrontendAction.cpp:967:8
    #35 0xc874011 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /usr/local/google/home/jgorbe/code/llvm/clang/lib/Frontend/CompilerInstance.cpp:1030:33
    #36 0xccbc008 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /usr/local/google/home/jgorbe/code/llvm/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:261:25
    #37 0x41b8a70 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/cc1_main.cpp:246:15
    #38 0x41b3db9 in ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:317:12
    #39 0x41b22a7 in main /usr/local/google/home/jgorbe/code/llvm/clang/tools/driver/driver.cpp:388:12
    #40 0x7f9bd7d73e49 in __libc_start_main csu/../csu/libc-start.c:314:16

SUMMARY: AddressSanitizer: heap-use-after-free /usr/local/google/home/jgorbe/code/llvm/llvm/include/llvm/CodeGen/DIE.h:537:14 in push_back
Shadow bytes around the buggy address:
  0x0c428001a8a0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a8b0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a8c0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a8d0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a8e0: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c428001a8f0:[fd]fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a900: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a910: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a920: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a930: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c428001a940: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==65688==ABORTING

[ellis]

Hi @jgorbe and @akuegel

Thanks for the info and taking care of the reverts! I've been investigating the memory bug and it looks like it existed before, but my patch triggered the failure. I'm still trying to figure it out, but hopefully I can come up with a fix.

[ellis]

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

1149–1153

I believe the bug is here. When using the -generate-type-units flag we cannot share DIEs accross CUs, but SPDie could come from a different CU.

The crash happened at DwarfDebug.cpp:addDwarfTypeUnitType() because a DIE was created, added to the child of a DIE in another unit, then destroyed in addDwarfTypeUnitType() while the parent DIE still existed.

I have a patch that I think works fine on the abseil-cpp project, so I'll upload that soon.

[dblaikie]

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

1149–1153

We shouldn't (& yes, can't in the current architecture that creates type units and then emits them immediately and cleans up the data structure, to reduce peak memory usage) use cross-unit references to refer to contents of type units - but when type units are enabled we should still use cross-unit references between compilation units.

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
   } else {
     ContextDIE = getOrCreateContextDIE(SP->getScope());
     // The scope may be shared with a subprogram that has already been
     // constructed in another CU, in which case we need to construct this
     // subprogram in the same CU.
     ContextCU = DD->lookupCU(ContextDIE->getUnitDie());
   }
 
-  // Passing null as the associated node because the abstract definition
-  // shouldn't be found by lookup.
-  AbsDef = &ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
+  // The abstract definition can only be looked up from the associated node if
+  // the subprogram does not have a concrete function.
+  if (!ContextCU->DD->IsConcrete(SP))
+    AbsDef = ContextCU->getDIE(SP);
+  if (!AbsDef)
+    AbsDef = &ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
+                                         nullptr);
+
   ContextCU->applySubprogramAttributesToDefinition(SP, *AbsDef);
   ContextCU->addSInt(*AbsDef, dwarf::DW_AT_inline,
                      DD->getDwarfVersion() <= 4 ? Optional<dwarf::Form>()
                                                 : dwarf::DW_FORM_implicit_const,
                      dwarf::DW_INL_inlined);
   if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
     ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
 }
DIE *DwarfCompileUnit::constructImportedEntityDIE(
   }
 
   return IMDie;
 }
 
 void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
   DIE *D = getDIE(SP);
   if (DIE *AbsSPDIE = getAbstractSPDies().lookup(SP)) {
-    if (D)
+    if (D && D != AbsSPDIE)
       // If this subprogram has an abstract definition, reference that
       addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
   } else {
     assert(D || includeMinimalInlineScopes());
     if (D)
       // And attach the attributes
       applySubprogramAttributesToDefinition(SP, *D);
   }

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

class DwarfDebug : public DebugHandlerBase {
 
   /// Collection of abstract variables/labels.
   SmallVector<std::unique_ptr<DbgEntity>, 64> ConcreteEntities;
 
   /// Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
   /// can refer to them in spite of insertions into this list.
   DebugLocStream DebugLocs;
 
+  using SubprogramSetVector =
+      SetVector<const DISubprogram *, SmallVector<const DISubprogram *, 16>,
+                SmallPtrSet<const DISubprogram *, 16>>;
+
   /// This is a collection of subprogram MDNodes that are processed to
   /// create DIEs.
-  SetVector<const DISubprogram *, SmallVector<const DISubprogram *, 16>,
-            SmallPtrSet<const DISubprogram *, 16>>
-      ProcessedSPNodes;
+  SubprogramSetVector ProcessedSPNodes;
+
+  /// The set of subprograms that have concrete functions.
+  /// This does not include subprograms of machine outlined functions because
+  /// they are created after this set is computed.
+  SubprogramSetVector ConcreteSPs;
 
   /// If nonnull, stores the current machine function we're processing.
   const MachineFunction *CurFn = nullptr;
 
   /// If nonnull, stores the CU in which the previous subprogram was contained.
   const DwarfCompileUnit *PrevCU = nullptr;
 
   /// As an optimization, there is no need to emit an entry in the directory
public:
 
   static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
                                 const DbgValueLoc &Value,
                                 DwarfExpression &DwarfExpr);
 
   /// If the \p File has an MD5 checksum, return it as an MD5Result
   /// allocated in the MCContext.
   Optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
+
+  /// Returns true if the subprogram has a function that will be emitted.
+  /// Returns false for subprograms of machine outlined functions even when
+  /// they do have concrete instances, but they should never have abstract
+  /// subprograms anyway.
+  bool IsConcrete(const DISubprogram *SP) const {
+    return ConcreteSPs.count(SP);
+  }
 };
 
 } // end namespace llvm
 
 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

if (!Asm || !MMI->hasDebugInfo())
     return;
 
   unsigned NumDebugCUs = std::distance(M->debug_compile_units_begin(),
                                        M->debug_compile_units_end());
   assert(NumDebugCUs > 0 && "Asm unexpectedly initialized");
   assert(MMI->hasDebugInfo() &&
          "DebugInfoAvailabilty unexpectedly not initialized");
   SingleCU = NumDebugCUs == 1;
+
+  for (const auto &F : M->functions())
+    if (!F.isDeclaration())
+      if (const auto *SP = F.getSubprogram())
+        ConcreteSPs.insert(SP);
+
   DenseMap<DIGlobalVariable *, SmallVector<DwarfCompileUnit::GlobalExpr, 1>>
       GVMap;
   for (const GlobalVariable &Global : M->globals()) {
     SmallVector<DIGlobalVariableExpression *, 1> GVs;
     Global.getDebugInfo(GVs);
     for (auto *GVE : GVs)
       GVMap[GVE->getVariable()].push_back({&Global, GVE->getExpression()});
   }

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

if (auto *SPDecl = SP->getDeclaration()) {
     if (!Minimal) {
       // Add subprogram definitions to the CU die directly.
       ContextDIE = &getUnitDie();
       // Build the decl now to ensure it precedes the definition.
       getOrCreateSubprogramDIE(SPDecl);
     }
   }
 
+  // Try to reference the abstract origin if the subprogram is not concrete.
+  if (!DD->IsConcrete(SP))
+    if (auto *SPDie = DU->getAbstractSPDies().lookup(SP))
+      return SPDie;
+
   // DW_TAG_inlined_subroutine may refer to this DIE.
   DIE &SPDie = createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, SP);
 
   // Stop here and fill this in later, depending on whether or not this
   // subprogram turns out to have inlined instances or not.
   if (SP->isDefinition())
     return &SPDie;
 

llvm/test/DebugInfo/Generic/import-inlined-declaration.ll

+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump - | FileCheck --implicit-check-not "{{DW_TAG|NULL}}" %s
+
+; namespace ns {
+; inline __attribute__((always_inline))
+; void foo() { int a = 4; }
+; }
+;
+; void goo() {
+;   using ns::foo;
+;   foo();
+; }
+
+; Ensure that imported declarations reference the correct subprograms even if
+; those subprograms are inlined.
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_namespace
+; CHECK:     DW_AT_name     ("ns")
+; CHECK: [[FOO:0x.*]]:     DW_TAG_subprogram
+; CHECK:       DW_AT_name   ("foo")
+; CHECK:       DW_TAG_variable
+; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   DW_TAG_base_type
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name     ("goo")
+; CHECK:     DW_TAG_imported_declaration
+; CHECK:       DW_AT_import ([[FOO]])
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:       DW_AT_abstract_origin ([[FOO]]
+; CHECK:       DW_TAG_variable
+; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   NULL
+
+; Function Attrs: mustprogress noinline optnone uwtable
+define dso_local void @_Z3goov() !dbg !4 {
+entry:
+  %a.i = alloca i32, align 4
+  call void @llvm.dbg.declare(metadata i32* %a.i, metadata !16, metadata !DIExpression()), !dbg !18
+  store i32 4, i32* %a.i, align 4, !dbg !18
+  ret void, !dbg !20
+}
+
+; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!10, !11, !12, !13, !14}
+!llvm.ident = !{!15}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, imports: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "imported-inlined-declaration.cpp", directory: "")
+!2 = !{!3}
+!3 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !8, file: !1, line: 7)
+!4 = distinct !DISubprogram(name: "goo", linkageName: "_Z3goov", scope: !1, file: !1, line: 6, type: !5, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !7)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{}
+!8 = distinct !DISubprogram(name: "foo", linkageName: "_ZN2ns3fooEv", scope: !9, file: !1, line: 3, type: !5, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !7)
+!9 = !DINamespace(name: "ns", scope: null)
+!10 = !{i32 7, !"Dwarf Version", i32 4}
+!11 = !{i32 2, !"Debug Info Version", i32 3}
+!12 = !{i32 1, !"wchar_size", i32 4}
+!13 = !{i32 7, !"uwtable", i32 1}
+!14 = !{i32 7, !"frame-pointer", i32 2}
+!15 = !{!"clang version 14.0.0"}
+!16 = !DILocalVariable(name: "a", scope: !8, file: !1, line: 3, type: !17)
+!17 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!18 = !DILocation(line: 3, column: 18, scope: !8, inlinedAt: !19)
+!19 = distinct !DILocation(line: 8, column: 2, scope: !4)
+!20 = !DILocation(line: 9, column: 1, scope: !4)

llvm/test/DebugInfo/Generic/inlined-local-type.ll

+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-info - | FileCheck --implicit-check-not "{{DW_TAG|NULL}}" %s
+
+; inline __attribute__((always_inline))
+; int removed() { struct A {int i;}; struct A a; return a.i++; }
+;
+; __attribute__((always_inline))
+; int not_removed() { struct B {int i;}; struct B b; return b.i++; }
+;
+; int foo() { return removed() + not_removed(); }}
+
+; Ensure that function-local types have the correct subprogram parent even if
+; those subprograms are inlined.
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_abstract_origin  ({{0x.*}} "not_removed")
+; CHECK:     DW_TAG_variable
+; CHECK: [[B:0x.*]]: DW_TAG_structure_type
+; CHECK:       DW_AT_name ("B")
+; CHECK:       DW_TAG_member
+; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name ("removed")
+; CHECK: [[A:0x.*]]: DW_TAG_structure_type
+; CHECK:       DW_AT_name ("A")
+; CHECK:       DW_TAG_member
+; CHECK:       NULL
+; CHECK:     DW_TAG_variable
+; CHECK:       DW_AT_type ([[A]] "A")
+; CHECK:     NULL
+; CHECK:   DW_TAG_base_type
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name ("not_removed")
+; CHECK:     DW_TAG_variable
+; CHECK:       DW_AT_type ([[B]] "B")
+; CHECK:     NULL
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:       DW_TAG_variable
+; CHECK:       NULL
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:       DW_TAG_variable
+; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   NULL
+
+%struct.B = type { i32 }
+%struct.A = type { i32 }
+
+define dso_local i32 @not_removed() !dbg !12 {
+  %1 = alloca %struct.B, align 4
+  call void @llvm.dbg.declare(metadata %struct.B* %1, metadata !18, metadata !DIExpression()), !dbg !22
+  %2 = getelementptr inbounds %struct.B, %struct.B* %1, i32 0, i32 0, !dbg !23
+  %3 = load i32, i32* %2, align 4, !dbg !24
+  %4 = add nsw i32 %3, 1, !dbg !24
+  store i32 %4, i32* %2, align 4, !dbg !24
+  ret i32 %3, !dbg !25
+}
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+define dso_local i32 @foo() !dbg !26 {
+  %1 = alloca %struct.A, align 4
+  %2 = alloca %struct.B, align 4
+  call void @llvm.dbg.declare(metadata %struct.A* %1, metadata !27, metadata !DIExpression()), !dbg !32
+  %3 = getelementptr inbounds %struct.A, %struct.A* %1, i32 0, i32 0, !dbg !34
+  %4 = load i32, i32* %3, align 4, !dbg !35
+  %5 = add nsw i32 %4, 1, !dbg !35
+  store i32 %5, i32* %3, align 4, !dbg !35
+  call void @llvm.dbg.declare(metadata %struct.B* %2, metadata !18, metadata !DIExpression()), !dbg !36
+  %6 = getelementptr inbounds %struct.B, %struct.B* %2, i32 0, i32 0, !dbg !38
+  %7 = load i32, i32* %6, align 4, !dbg !39
+  %8 = add nsw i32 %7, 1, !dbg !39
+  store i32 %8, i32* %6, align 4, !dbg !39
+  %9 = add nsw i32 %4, %7, !dbg !40
+  ret i32 %9, !dbg !41
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8, !9, !10}
+!llvm.ident = !{!11}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "inlined-local-type.cpp", directory: "")
+!2 = !{i32 7, !"Dwarf Version", i32 4}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{i32 1, !"branch-target-enforcement", i32 0}
+!6 = !{i32 1, !"sign-return-address", i32 0}
+!7 = !{i32 1, !"sign-return-address-all", i32 0}
+!8 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
+!9 = !{i32 7, !"uwtable", i32 1}
+!10 = !{i32 7, !"frame-pointer", i32 1}
+!11 = !{!"clang version 14.0.0"}
+!12 = distinct !DISubprogram(name: "not_removed", scope: !13, file: !13, line: 5, type: !14, scopeLine: 5, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !17)
+!13 = !DIFile(filename: "inlined-local-type.cpp", directory: "")
+!14 = !DISubroutineType(types: !15)
+!15 = !{!16}
+!16 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!17 = !{}
+!18 = !DILocalVariable(name: "b", scope: !12, file: !13, line: 5, type: !19)
+!19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "B", scope: !12, file: !13, line: 5, size: 32, elements: !20)
+!20 = !{!21}
+!21 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !19, file: !13, line: 5, baseType: !16, size: 32)
+!22 = !DILocation(line: 5, column: 49, scope: !12)
+!23 = !DILocation(line: 5, column: 61, scope: !12)
+!24 = !DILocation(line: 5, column: 62, scope: !12)
+!25 = !DILocation(line: 5, column: 52, scope: !12)
+!26 = distinct !DISubprogram(name: "foo", scope: !13, file: !13, line: 7, type: !14, scopeLine: 7, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !17)
+!27 = !DILocalVariable(name: "a", scope: !28, file: !13, line: 2, type: !29)
+!28 = distinct !DISubprogram(name: "removed", scope: !13, file: !13, line: 2, type: !14, scopeLine: 2, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !17)
+!29 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "A", scope: !28, file: !13, line: 2, size: 32, elements: !30)
+!30 = !{!31}
+!31 = !DIDerivedType(tag: DW_TAG_member, name: "i", scope: !29, file: !13, line: 2, baseType: !16, size: 32)
+!32 = !DILocation(line: 2, column: 45, scope: !28, inlinedAt: !33)
+!33 = distinct !DILocation(line: 7, column: 20, scope: !26)
+!34 = !DILocation(line: 2, column: 57, scope: !28, inlinedAt: !33)
+!35 = !DILocation(line: 2, column: 58, scope: !28, inlinedAt: !33)
+!36 = !DILocation(line: 5, column: 49, scope: !12, inlinedAt: !37)
+!37 = distinct !DILocation(line: 7, column: 32, scope: !26)
+!38 = !DILocation(line: 5, column: 61, scope: !12, inlinedAt: !37)
+!39 = !DILocation(line: 5, column: 62, scope: !12, inlinedAt: !37)
+!40 = !DILocation(line: 7, column: 30, scope: !26)
+!41 = !DILocation(line: 7, column: 13, scope: !26)

llvm/test/DebugInfo/Generic/inlined-static-var.ll

+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-info - | FileCheck --implicit-check-not "{{DW_TAG|NULL}}" %s
+
+; inline __attribute__((always_inline))
+; int removed() { static int A; return A++; }
+;
+; __attribute__((always_inline))
+; int not_removed() { static int B; return B++; }
+;
+; int foo() { return removed() + not_removed(); }
+
+; Ensure that global variables belong to the correct subprograms even if those
+; subprograms are inlined.
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_subprogram
+; TODO: Place the variable in the abstract DIE rather than this concrete DIE.
+; CHECK:     DW_TAG_variable
+; CHECK:       DW_AT_name     ("B")
+; CHECK:     NULL
+; CHECK:   DW_TAG_base_type
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name       ("removed")
+; CHECK:     DW_TAG_variable
+; CHECK:       DW_AT_name     ("A")
+; CHECK:     NULL
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name       ("not_removed")
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name       ("foo")
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:     NULL
+; CHECK:   NULL
+
+$_ZZ7removedvE1A = comdat any
+
+@_ZZ11not_removedvE1A = internal global i32 0, align 4, !dbg !0
+@_ZZ7removedvE1A = linkonce_odr dso_local global i32 0, comdat, align 4, !dbg !10
+
+define dso_local i32 @_Z11not_removedv() !dbg !2 {
+  %1 = load i32, i32* @_ZZ11not_removedvE1A, align 4, !dbg !24
+  %2 = add nsw i32 %1, 1, !dbg !24
+  store i32 %2, i32* @_ZZ11not_removedvE1A, align 4, !dbg !24
+  ret i32 %1, !dbg !25
+}
+
+define dso_local i32 @_Z3foov() !dbg !26 {
+  %1 = load i32, i32* @_ZZ7removedvE1A, align 4, !dbg !27
+  %2 = add nsw i32 %1, 1, !dbg !27
+  store i32 %2, i32* @_ZZ7removedvE1A, align 4, !dbg !27
+  %3 = load i32, i32* @_ZZ11not_removedvE1A, align 4, !dbg !29
+  %4 = add nsw i32 %3, 1, !dbg !29
+  store i32 %4, i32* @_ZZ11not_removedvE1A, align 4, !dbg !29
+  %5 = add nsw i32 %1, %3, !dbg !31
+  ret i32 %5, !dbg !32
+}
+
+!llvm.dbg.cu = !{!7}
+!llvm.module.flags = !{!14, !15, !16, !17, !18, !19, !20, !21, !22}
+!llvm.ident = !{!23}
+
+!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
+!1 = distinct !DIGlobalVariable(name: "B", scope: !2, file: !3, line: 5, type: !6, isLocal: true, isDefinition: true)
+!2 = distinct !DISubprogram(name: "not_removed", linkageName: "_Z11not_removedv", scope: !3, file: !3, line: 5, type: !4, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !13)
+!3 = !DIFile(filename: "example.cpp", directory: "")
+!4 = !DISubroutineType(types: !5)
+!5 = !{!6}
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !8, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !9, splitDebugInlining: false, nameTableKind: None)
+!8 = !DIFile(filename: "example.cpp", directory: "")
+!9 = !{!0, !10}
+!10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression())
+!11 = distinct !DIGlobalVariable(name: "A", scope: !12, file: !3, line: 2, type: !6, isLocal: false, isDefinition: true)
+!12 = distinct !DISubprogram(name: "removed", linkageName: "_Z7removedv", scope: !3, file: !3, line: 2, type: !4, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !13)
+!13 = !{}
+!14 = !{i32 7, !"Dwarf Version", i32 4}
+!15 = !{i32 2, !"Debug Info Version", i32 3}
+!16 = !{i32 1, !"wchar_size", i32 4}
+!17 = !{i32 1, !"branch-target-enforcement", i32 0}
+!18 = !{i32 1, !"sign-return-address", i32 0}
+!19 = !{i32 1, !"sign-return-address-all", i32 0}
+!20 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
+!21 = !{i32 7, !"uwtable", i32 1}
+!22 = !{i32 7, !"frame-pointer", i32 1}
+!23 = !{!"clang version 14.0.0"}
+!24 = !DILocation(line: 5, column: 43, scope: !2)
+!25 = !DILocation(line: 5, column: 35, scope: !2)
+!26 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !3, file: !3, line: 7, type: !4, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !7, retainedNodes: !13)
+!27 = !DILocation(line: 2, column: 39, scope: !12, inlinedAt: !28)
+!28 = distinct !DILocation(line: 7, column: 20, scope: !26)
+!29 = !DILocation(line: 5, column: 43, scope: !2, inlinedAt: !30)
+!30 = distinct !DILocation(line: 7, column: 32, scope: !26)
+!31 = !DILocation(line: 7, column: 30, scope: !26)
+!32 = !DILocation(line: 7, column: 13, scope: !26)