[llvm] r219215 - DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself.

Adam Nemet anemet at apple.com
Fri Oct 10 11:07:48 PDT 2014


On Oct 7, 2014, at 9:56 AM, David Blaikie <dblaikie at gmail.com> wrote:

> Author: dblaikie
> Date: Tue Oct  7 11:56:20 2014
> New Revision: 219215
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=219215&view=rev
> Log:
> DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself.
> 
> Let me tell you a tale...
> 
> Originally committed in r211723 after discovering a nasty case of weird
> scoping due to inlining, this was reverted in r211724 after it fired in
> ASan/compiler-rt.
> 
> (minor diversion where I accidentally committed/reverted again in
> r211871/r211873)
> 
> After further testing and fixing bugs in ArgumentPromotion (r211872) and
> Inlining (r212065) it was recommitted in r212085. Reverted in r212089
> after the sanitizer buildbots still showed problems.
> 
> Fixed another bug in ArgumentPromotion (r212128) found by this
> assertion.
> 
> Recommitted in r212205, reverted in r212226 after it crashed some more
> on sanitizer buildbots.
> 
> Fix clang some more in r212761.
> 
> Recommitted in r212776, reverted in r212793. ASan failures.
> Recommitted in r213391, reverted in r213432, trying to reproduce flakey
> ASan build failure.
> 
> Fixed bugs in r213805 (ArgPromo + DebugInfo), r213952
> (LiveDebugVariables strips dbg_value intrinsics in functions not
> described by debug info).
> 
> Recommitted in r214761, reverted in r214999, flakey failure on Windows
> buildbot.
> 
> Fixed DeadArgElimination + DebugInfo bug in r219210.
> 
> Recommitting and hoping that's the last of it.
> 
> [That one burned down, fell over, then sank into the swamp.]

Hi David,

Unfortunately, this may not be the end of the tale yet...  We’re seeing the new assert triggered with test-suite/SingleSource/UnitTests/ObjC++/property-reference-object.mm using -O0 -g on x86_64:

/org/llvm/build$ ./Debug+Asserts/bin/clang++ /org/test-suite/SingleSource/UnitTests/ObjC++/property-reference-object.mm -O0 -g -arch x86_64 -m64 -fomit-frame-pointer -mdynamic-no-pic -c
Assertion failed: (DISubprogram(Scope).describes(MF->getFunction())), function getOrCreateRegularScope, file /Users/anemet/proj/org/llvm/lib/CodeGen/LexicalScopes.cpp, line 179.
0  clang                    0x000000010b8ee19e llvm::sys::PrintStackTrace(__sFILE*) + 46
1  clang                    0x000000010b8ee4ab PrintStackTraceSignalHandler(void*) + 27
2  clang                    0x000000010b8ee8c1 SignalHandler(int) + 561
3  libsystem_platform.dylib 0x00007fff8a7da5aa _sigtramp + 26
4  clang                    0x000000010be8fc0c std::__1::piecewise_construct + 0
5  clang                    0x000000010b8ee4db raise + 27
6  clang                    0x000000010b8ee592 abort + 18
7  clang                    0x000000010b8ee571 __assert_rtn + 129
8  clang                    0x000000010ac4b9e6 llvm::LexicalScopes::getOrCreateRegularScope(llvm::MDNode*) + 2854
9  clang                    0x000000010ac48f9c llvm::LexicalScopes::getOrCreateLexicalScope(llvm::DebugLoc) + 188
10 clang                    0x000000010ac489df llvm::LexicalScopes::extractLexicalScopes(llvm::SmallVectorImpl<std::__1::pair<llvm::MachineInstr const*, llvm::MachineInstr const*> >&, llvm::DenseMap<llvm::MachineInstr const*, llvm::LexicalScope*, llvm::DenseMapInfo<llvm::MachineInstr const*> >&) + 607
11 clang                    0x000000010ac486f6 llvm::LexicalScopes::initialize(llvm::MachineFunction const&) + 118
12 clang                    0x000000010ab2b7dc llvm::DwarfDebug::beginFunction(llvm::MachineFunction const*) + 252
13 clang                    0x000000010aadff16 llvm::AsmPrinter::EmitFunctionHeader() + 1302
14 clang                    0x000000010a697a46 llvm::X86AsmPrinter::runOnMachineFunction(llvm::MachineFunction&) + 262
15 clang                    0x000000010ad00a2e llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 110
16 clang                    0x000000010b80891f llvm::FPPassManager::runOnFunction(llvm::Function&) + 431
17 clang                    0x000000010b808c08 llvm::FPPassManager::runOnModule(llvm::Module&) + 104
18 clang                    0x000000010b8095d6 (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) + 1350
19 clang                    0x000000010b808ebe llvm::legacy::PassManagerImpl::run(llvm::Module&) + 302
20 clang                    0x000000010b809d21 llvm::legacy::PassManager::run(llvm::Module&) + 33
21 clang                    0x0000000107ceef51 (anonymous namespace)::EmitAssemblyHelper::EmitAssembly(clang::BackendAction, llvm::raw_ostream*) + 1601
22 clang                    0x0000000107cee702 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::raw_ostream*) + 114
23 clang                    0x0000000107ee2d65 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) + 1733
24 clang                    0x00000001080327b4 clang::ParseAST(clang::Sema&, bool, bool) + 1268
25 clang                    0x0000000107a1d98a clang::ASTFrontendAction::ExecuteAction() + 522
26 clang                    0x0000000107ee0d09 clang::CodeGenAction::ExecuteAction() + 3785
27 clang                    0x0000000107a1cef8 clang::FrontendAction::Execute() + 120
28 clang                    0x00000001079b136f clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1007
29 clang                    0x00000001078d8ec0 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 3136
30 clang                    0x00000001078ba79b cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 2395
31 clang                    0x00000001078ceea6 ExecuteCC1Tool(llvm::ArrayRef<char const*>, llvm::StringRef) + 198
32 clang                    0x00000001078ce4a8 main + 1288
33 libdyld.dylib            0x00007fff8ffe95fd start + 1

As expected reverting the commit fixes the assert.  Can you please take a look?

Thanks,
Adam


> 
> Modified:
>    llvm/trunk/lib/CodeGen/LexicalScopes.cpp
>    llvm/trunk/lib/IR/DebugInfo.cpp
> 
> Modified: llvm/trunk/lib/CodeGen/LexicalScopes.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LexicalScopes.cpp?rev=219215&r1=219214&r2=219215&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/LexicalScopes.cpp (original)
> +++ llvm/trunk/lib/CodeGen/LexicalScopes.cpp Tue Oct  7 11:56:20 2014
> @@ -137,6 +137,8 @@ LexicalScope *LexicalScopes::findLexical
> /// getOrCreateLexicalScope - Find lexical scope for the given DebugLoc. If
> /// not available then create new lexical scope.
> LexicalScope *LexicalScopes::getOrCreateLexicalScope(DebugLoc DL) {
> +  if (DL.isUnknown())
> +    return nullptr;
>   MDNode *Scope = nullptr;
>   MDNode *InlinedAt = nullptr;
>   DL.getScopeAndInlinedAt(Scope, InlinedAt, MF->getFunction()->getContext());
> @@ -172,9 +174,12 @@ LexicalScope *LexicalScopes::getOrCreate
>                               std::make_tuple(Parent, DIDescriptor(Scope),
>                                               nullptr, false)).first;
> 
> -  if (!Parent && DIDescriptor(Scope).isSubprogram() &&
> -      DISubprogram(Scope).describes(MF->getFunction()))
> +  if (!Parent) {
> +    assert(DIDescriptor(Scope).isSubprogram());
> +    assert(DISubprogram(Scope).describes(MF->getFunction()));
> +    assert(!CurrentFnLexicalScope);
>     CurrentFnLexicalScope = &I->second;
> +  }
> 
>   return &I->second;
> }
> 
> Modified: llvm/trunk/lib/IR/DebugInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DebugInfo.cpp?rev=219215&r1=219214&r2=219215&view=diff
> ==============================================================================
> --- llvm/trunk/lib/IR/DebugInfo.cpp (original)
> +++ llvm/trunk/lib/IR/DebugInfo.cpp Tue Oct  7 11:56:20 2014
> @@ -568,6 +568,34 @@ bool DISubprogram::Verify() const {
>   if (isLValueReference() && isRValueReference())
>     return false;
> 
> +  // If a DISubprogram has an llvm::Function*, then scope chains from all
> +  // instructions within the function should lead to this DISubprogram.
> +  if (auto *F = getFunction()) {
> +    LLVMContext &Ctxt = F->getContext();
> +    for (auto &BB : *F) {
> +      for (auto &I : BB) {
> +        DebugLoc DL = I.getDebugLoc();
> +        if (DL.isUnknown())
> +          continue;
> +
> +        MDNode *Scope = nullptr;
> +        MDNode *IA = nullptr;
> +        // walk the inlined-at scopes
> +        while (DL.getScopeAndInlinedAt(Scope, IA, F->getContext()), IA)
> +          DL = DebugLoc::getFromDILocation(IA);
> +        DL.getScopeAndInlinedAt(Scope, IA, Ctxt);
> +        assert(!IA);
> +        while (!DIDescriptor(Scope).isSubprogram()) {
> +          DILexicalBlockFile D(Scope);
> +          Scope = D.isLexicalBlockFile()
> +                      ? D.getScope()
> +                      : DebugLoc::getFromDILexicalBlock(Scope).getScope(Ctxt);
> +        }
> +        if (!DISubprogram(Scope).describes(F))
> +          return false;
> +      }
> +    }
> +  }
>   return DbgNode->getNumOperands() == 9 && getNumHeaderFields() == 12;
> }
> 
> 
> 
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