[PATCH] D125802: Fix std::has_unique_object_representations for _BitInt types with padding bits

Wed Jun 1 13:07:51 PDT 2022

aaron.ballman added inline comments.

================
Comment at: clang/test/SemaCXX/has_unique_object_reps_bitint.cpp:1
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify -std=c++17 -Wno-bitfield-width %s
+//  expected-no-diagnostics
----------------
browneee wrote:
> This unit test appears to trigger a memory leak:
> 
> https://lab.llvm.org/buildbot/#/builders/5/builds/24359/steps/15/logs/stdio
> 
> ```
> FAIL: Clang :: SemaCXX/has_unique_object_reps_bitint.cpp (13615 of 66177)
> ******************** TEST 'Clang :: SemaCXX/has_unique_object_reps_bitint.cpp' FAILED ********************
> Script:
> --
> : 'RUN: at line 1';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_asan/bin/clang -cc1 -internal-isystem /b/sanitizer-x86_64-linux-fast/build/llvm_build_asan/lib/clang/15.0.0/include -nostdsysteminc -triple x86_64-unknown-unknown -fsyntax-only -verify -std=c++17 -Wno-bitfield-width /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/test/SemaCXX/has_unique_object_reps_bitint.cpp
> --
> Exit Code: 1
> Command Output (stderr):
> --
> =================================================================
> ==22556==ERROR: LeakSanitizer: detected memory leaks
> Direct leak of 1632 byte(s) in 3 object(s) allocated from:
>     #0 0x55cc84e8d6be in malloc /b/s/w/ir/cache/builder/src/third_party/llvm/compiler-rt/lib/asan/asan_malloc_linux.cpp:69:3
>     #1 0x55cc8c0a417c in safe_malloc /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/Support/MemAlloc.h:26:18
>     #2 0x55cc8c0a417c in llvm::SmallVectorBase<unsigned int>::grow_pod(void*, unsigned long, unsigned long) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Support/SmallVector.cpp:126:15
>     #3 0x55cc94342e34 in grow_pod /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:120:11
>     #4 0x55cc94342e34 in grow /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:506:41
>     #5 0x55cc94342e34 in reserveForParamAndGetAddressImpl<llvm::SmallVectorTemplateBase<clang::TemplateArgumentLoc, true> > /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:225:11
>     #6 0x55cc94342e34 in reserveForParamAndGetAddress /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:511:12
>     #7 0x55cc94342e34 in push_back /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/include/llvm/ADT/SmallVector.h:543:23
>     #8 0x55cc94342e34 in addArgument /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/include/clang/AST/TemplateBase.h:604:15
>     #9 0x55cc94342e34 in clang::VarTemplateSpecializationDecl::setTemplateArgsInfo(clang::TemplateArgumentListInfo const&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/AST/DeclTemplate.cpp:1341:22
>     #10 0x55cc937d5b66 in clang::TemplateDeclInstantiator::VisitVarTemplateSpecializationDecl(clang::VarTemplateDecl*, clang::VarDecl*, clang::TemplateArgumentListInfo const&, llvm::ArrayRef<clang::TemplateArgument>, clang::VarTemplateSpecializationDecl*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:3860:8
>     #11 0x55cc937e1dd4 in clang::Sema::BuildVarTemplateInstantiation(clang::VarTemplateDecl*, clang::VarDecl*, clang::TemplateArgumentList const&, clang::TemplateArgumentListInfo const&, llvm::SmallVectorImpl<clang::TemplateArgument>&, clang::SourceLocation, llvm::SmallVector<clang::Sema::LateInstantiatedAttribute, 16u>*, clang::LocalInstantiationScope*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:5135:20
>     #12 0x55cc933d777d in clang::Sema::CheckVarTemplateId(clang::VarTemplateDecl*, clang::SourceLocation, clang::SourceLocation, clang::TemplateArgumentListInfo const&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Sema/SemaTemplate.cpp:4621:41
>     #13 0x55cc933daddc in CheckVarTemplateId /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Sema/SemaTemplate.cpp:4657:21
>     #14 0x55cc933daddc in clang::Sema::BuildTemplateIdExpr(clang::CXXScopeSpec const&, clang::SourceLocation, clang::LookupResult&, bool, clang::TemplateArgumentListInfo const*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Sema/SemaTemplate.cpp:4748:22
>     #15 0x55cc928ffef3 in clang::Sema::ActOnIdExpression(clang::Scope*, clang::CXXScopeSpec&, clang::SourceLocation, clang::UnqualifiedId&, bool, bool, clang::CorrectionCandidateCallback*, bool, clang::Token*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Sema/SemaExpr.cpp:2728:12
>     #16 0x55cc91d0e988 in clang::Parser::tryParseCXXIdExpression(clang::CXXScopeSpec&, bool, clang::Token&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseExprCXX.cpp:610:17
>     #17 0x55cc91d124d9 in clang::Parser::ParseCXXIdExpression(bool) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseExprCXX.cpp:676:7
>     #18 0x55cc91cdb510 in clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseExpr.cpp:1626:11
>     #19 0x55cc91ce0476 in clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, bool&, clang::Parser::TypeCastState, bool, bool*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseExpr.cpp
>     #20 0x55cc91cd0635 in clang::Parser::ParseCastExpression(clang::Parser::CastParseKind, bool, clang::Parser::TypeCastState, bool, bool*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseExpr.cpp:681:20
>     #21 0x55cc91cd8160 in clang::Parser::ParseConstantExpressionInExprEvalContext(clang::Parser::TypeCastState) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseExpr.cpp:206:18
>     #22 0x55cc91d51601 in clang::Parser::ParseStaticAssertDeclaration(clang::SourceLocation&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:949:25
>     #23 0x55cc91dc0cb8 in clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::SourceLocation*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseDecl.cpp:1794:18
>     #24 0x55cc91bdb92e in clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsingDeclSpec*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/Parser.cpp:932:14
>     #25 0x55cc91bd3349 in clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/Parser.cpp:727:12
>     #26 0x55cc91bbb01e in clang::ParseAST(clang::Sema&, bool, bool) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Parse/ParseAST.cpp:162:20
>     #27 0x55cc8e33d5d4 in clang::FrontendAction::Execute() /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Frontend/FrontendAction.cpp:1032:8
>     #28 0x55cc8e16f390 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/Frontend/CompilerInstance.cpp:1033:33
>     #29 0x55cc8e5b6b76 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:266:25
>     #30 0x55cc84edab64 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/tools/driver/cc1_main.cpp:248:15
>     #31 0x55cc84ed3890 in ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/tools/driver/driver.cpp:317:12
>     #32 0x55cc84ed1dfe in main /b/sanitizer-x86_64-linux-fast/build/llvm-project/clang/tools/driver/driver.cpp:388:12
>     #33 0x7f14563da09a in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409a) (BuildId: eb6a5dd378d22b1e695984462a799cd4c81cdc22)
> SUMMARY: AddressSanitizer: 1632 byte(s) leaked in 3 allocation(s).
> ```
Huh, it looks to me like that leak may have been an existing issue that this test case uncovered (no part of that call stack would be impacted by the changes from this patch, as best I can tell).

@MitalAshok -- are you able to investigate the sanitizer behavior to validate my hunch?

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D125802