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Crash on syntax error: using MyClass::; #62296

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HolyBlackCat opened this issue Apr 22, 2023 · 12 comments · Fixed by llvm/llvm-project-release-prs#436
Closed

Crash on syntax error: using MyClass::; #62296

HolyBlackCat opened this issue Apr 22, 2023 · 12 comments · Fixed by llvm/llvm-project-release-prs#436
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@alanzhao1
Labels
c++20 clang:frontend Language frontend issues, e.g. anything involving "Sema" confirmed Verified by a second party crash-on-invalid regression release:backport release:merged
Milestone
LLVM 16.0.X Release

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@HolyBlackCat
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HolyBlackCat commented Apr 22, 2023 •
edited by VoltrexKeyva
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Here's the code, which I compile with -std=c++20.

struct A
{
protected:
    A(int) {}
};

struct B : A
{
    using A::; // Intentional error here.
};

int main()
{
    B b(42);
}

This crashes the compiler in addition to generating a diagnostic. Tested on Clang 16 and on trunk 9372e42 on GodBolt.

<source>:9:14: error: expected unqualified-id
    using A::; // Intentional error here.
             ^
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /opt/compiler-explorer/clang-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++20 <source>
1.	<source>:14:12: current parser token ';'
2.	<source>:13:1: parsing function body 'main'
3.	<source>:13:1: in compound statement ('{}')
 #0 0x000055dcab24da6f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x36f2a6f)
 #1 0x000055dcab24ba9c llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x36f0a9c)
 #2 0x000055dcab19d4e8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f32903e7420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
 #4 0x000055dcad8eed01 clang::Sema::computeDeclContext(clang::QualType) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5d93d01)
 #5 0x000055dcad8cfe9e HasAccess(clang::Sema&, (anonymous namespace)::EffectiveContext const&, clang::CXXRecordDecl const*, clang::AccessSpecifier, (anonymous namespace)::AccessTarget const&) (.part.0) SemaAccess.cpp:0:0
 #6 0x000055dcad8d0238 IsAccessible(clang::Sema&, (anonymous namespace)::EffectiveContext const&, (anonymous namespace)::AccessTarget&) SemaAccess.cpp:0:0
 #7 0x000055dcad8d2ab8 CheckEffectiveAccess(clang::Sema&, (anonymous namespace)::EffectiveContext const&, clang::SourceLocation, (anonymous namespace)::AccessTarget&) SemaAccess.cpp:0:0
 #8 0x000055dcad8d6e84 clang::Sema::HandleDelayedAccessCheck(clang::sema::DelayedDiagnostic&, clang::Decl*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5d7be84)
 #9 0x000055dcadacc7e2 clang::Sema::PopParsingDeclaration(clang::Sema::DelayedDiagnosticsState, clang::Decl*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5f717e2)
#10 0x000055dcad78fdbe clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c34dbe)
#11 0x000055dcad7907f6 clang::Parser::ParseSimpleDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, bool, clang::Parser::ForRangeInit*, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c357f6)
#12 0x000055dcad790d07 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c35d07)
#13 0x000055dcad83ee2e clang::Parser::ParseStatementOrDeclarationAfterAttributes(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*, clang::ParsedAttributes&, clang::ParsedAttributes&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5ce3e2e)
#14 0x000055dcad83f6e3 clang::Parser::ParseStatementOrDeclaration(llvm::SmallVector<clang::Stmt*, 32u>&, clang::Parser::ParsedStmtContext, clang::SourceLocation*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5ce46e3)
#15 0x000055dcad8405aa clang::Parser::ParseCompoundStatementBody(bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5ce55aa)
#16 0x000055dcad841962 clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5ce6962)
#17 0x000055dcad75d821 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c02821)
#18 0x000055dcad78f46f clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c3446f)
#19 0x000055dcad757c97 clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5bfcc97)
#20 0x000055dcad758def clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (.part.0) Parser.cpp:0:0
#21 0x000055dcad760874 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c05874)
#22 0x000055dcad761e2d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5c06e2d)
#23 0x000055dcad7511aa clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5bf61aa)
#24 0x000055dcac3b1e25 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4856e25)
#25 0x000055dcabc9fb51 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4144b51)
#26 0x000055dcabc220a3 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x40c70a3)
#27 0x000055dcabd7fed3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4224ed3)
#28 0x000055dca8b5bb8c cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x1000b8c)
#29 0x000055dca8b5734f ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#30 0x000055dcaba7d4bd void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#31 0x000055dcab19d947 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3642947)
#32 0x000055dcaba7d6fc clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#33 0x000055dcaba44adc clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ee9adc)
#34 0x000055dcaba454cd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3eea4cd)
#35 0x000055dcaba4fafc clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ef4afc)
#36 0x000055dca8b598ff clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xffe8ff)
#37 0x000055dca8a5a0e5 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xeff0e5)
#38 0x00007f328fe95083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#39 0x000055dca8b5352e _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xff852e)
clang++: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Compiler returned: 139
@tbaederr tbaederr added c++20 clang:frontend Language frontend issues, e.g. anything involving "Sema" crash-on-invalid and removed new issue labels Apr 22, 2023
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llvmbot commented Apr 22, 2023

@llvm/issue-subscribers-clang-frontend

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llvmbot commented Apr 22, 2023

@llvm/issue-subscribers-c-20

@AaronBallman AaronBallman added confirmed Verified by a second party regression labels Apr 22, 2023
@AaronBallman
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Worked in Clang 15, crashes in Clang 16: https://godbolt.org/z/YaTfsqfdo

@AaronBallman
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It's possible that the issue is here: https://github.com/llvm/llvm-project/blob/main/clang/lib/Sema/SemaInit.cpp#L6237

What I'm seeing is that OR is OR_No_Viable_Function, so we try to build a paren list initialization, and later when we go to Perform() that initialization, we fail because of an invalid current context object. However, I didn't have time to try to track it down farther than this, so it's possible the issue is actually elsewhere.

CC @alanzhao1 as this seems related to 95a4c0c and if this can be fixed so we can backport to a 16.x release, that would be great.

@alanzhao1
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Further reduction: https://godbolt.org/z/rrq5Th1zo

struct A
{
protected:
    A(int) {}
};

struct B : A {};

int main()
{
    B b(42);
}

It seems like the issue isn't the syntax error - the issue is that we're not rejecting the protected constructor A::A(int) when we perform an aggregate initialization.

@alanzhao1
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Candidate patch: https://reviews.llvm.org/D149301

@alanzhao1 alanzhao1 self-assigned this Apr 26, 2023
@alanzhao1
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/cherry-pick 7417e9d

@llvmbot
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llvmbot commented Apr 27, 2023

/cherry-pick 7417e9d

Error: Command failed due to missing milestone.

@alanzhao1 alanzhao1 added this to the LLVM 16.0.X Release milestone Apr 27, 2023
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/cherry-pick 7417e9d

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llvmbot commented Apr 27, 2023

Failed to cherry-pick: 7417e9d

https://github.com/llvm/llvm-project/actions/runs/4822933155

Please manually backport the fix and push it to your github fork. Once this is done, please add a comment like this:

/branch <user>/<repo>/<branch>

@alanzhao1
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/branch alanzhao1/llvm-project/init-crash-fix

@llvmbot llvmbot mentioned this issue Apr 27, 2023
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llvmbot commented Apr 27, 2023

/pull-request llvm/llvm-project-release-prs#436

@github-project-automation github-project-automation bot moved this to Needs Triage in LLVM Release Status May 2, 2023
@tstellar tstellar moved this from Needs Triage to Done in LLVM Release Status May 2, 2023
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@alanzhao1 alanzhao1

Labels
c++20 clang:frontend Language frontend issues, e.g. anything involving "Sema" confirmed Verified by a second party crash-on-invalid regression release:backport release:merged
Projects
LLVM Release Status
Archived in project
Milestone
LLVM 16.0.X Release
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PR for llvm/llvm-project#62296 llvm/llvm-project-release-prs
6 participants
@AaronBallman @alanzhao1 @EugeneZelenko @HolyBlackCat @tbaederr @llvmbot