| Issue |
179773
|
| Summary |
Crash in getTypeInfoImpl when combining _Atomic and __auto_type
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
EvanED
|
I work on tooling, and was adapting https://github.com/llvm/llvm-project/blob/e209b8bc2f87d53dc9003f7f09ce14b61894bf6c/clang/test/Sema/auto-type.c as a test case for my setting. I don't think I can really use `-fsyntax-only` (as your test case does), so I was building with `-c` (after removing error-producing lines, etc.); but this causes a crash that does not surface with `-fsyntax-only`. This crash occurs with `-emit-llvm -Xclang -disable-llvm-passes`.
The problem occurs with all the Clang versions I tested, including version 20, 21, and a couple recent-ish dev versions, built by both me and others. The stack trace I've posted below is from the version of clang packaged up in the Dockerhub image `silkeh/clang:21`.
Test case:
```
void Issue53652(void) {
_Atomic __auto_type aat1 = 4;
}
```
(Note that the name of this function I didn't change from your test case, but obviously the number in that name is independent of *this* issue.)
Command line: `clang -emit-llvm -Xclang -disable-llvm-passes -pedantic -std=c11 -c test.c`
Crash message:
```
test.c:2:11: warning: '__auto_type' is a GNU extension [-Wgnu-auto-type]
2 | _Atomic __auto_type aat1 = 4;
| ^
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: clang -emit-llvm -Xclang -disable-llvm-passes -pedantic -std=c11 -c test.c
1. <eof> parser at end of file
2. test.c:1:6: LLVM IR generation of declaration 'Issue53652'
3. test.c:1:6: Generating code for declaration 'Issue53652'
#0 0x00007c463ba62306 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/llvm-21/bin/../lib/libLLVM.so.21.1+0xbcc306)
#1 0x00007c463ba5fb53 llvm::sys::RunSignalHandlers() (/usr/lib/llvm-21/bin/../lib/libLLVM.so.21.1+0xbc9b53)
#2 0x00007c463b9982f0 (/usr/lib/llvm-21/bin/../lib/libLLVM.so.21.1+0xb022f0)
#3 0x00007c463a9d0050 (/lib/x86_64-linux-gnu/libc.so.6+0x3c050)
#4 0x00007c4644056b2e clang::ASTContext::getTypeInfoImpl(clang::Type const*) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0xc5db2e)
#5 0x00007c4644059033 (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0xc60033)
#6 0x00007c4644056eab clang::ASTContext::getTypeInfoImpl(clang::Type const*) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0xc5deab)
#7 0x00007c4644057ca1 clang::ASTContext::getPreferredTypeAlign(clang::Type const*) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0xc5eca1)
#8 0x00007c46440562c0 clang::ASTContext::getDeclAlign(clang::Decl const*, bool) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0xc5d2c0)
#9 0x00007c464518ebb3 clang::CodeGen::CodeGenFunction::EmitAutoVarAlloca(clang::VarDecl const&) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1d95bb3)
#10 0x00007c464518a7fc clang::CodeGen::CodeGenFunction::EmitVarDecl(clang::VarDecl const&) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1d917fc)
#11 0x00007c464518a45d clang::CodeGen::CodeGenFunction::EmitDecl(clang::Decl const&, bool) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1d9145d)
#12 0x00007c46453364c0 clang::CodeGen::CodeGenFunction::EmitSimpleStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1f3d4c0)
#13 0x00007c4645335a63 clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1f3ca63)
#14 0x00007c464534109c clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1f4809c)
#15 0x00007c46453a253e clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1fa953e)
#16 0x00007c46453c4c15 clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1fcbc15)
#17 0x00007c46453be49b clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1fc549b)
#18 0x00007c46453c23b5 clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1fc93b5)
#19 0x00007c46453bd0c1 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1fc40c1)
#20 0x00007c4645464eec (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x206beec)
#21 0x00007c4645392369 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x1f99369)
#22 0x00007c4643f7005a clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0xb7705a)
#23 0x00007c4645b2b80b clang::FrontendAction::Execute() (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x273280b)
#24 0x00007c4645a9cb94 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x26a3b94)
#25 0x00007c4645bb3c2e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x27bac2e)
#26 0x0000613bc38e9939 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/lib/llvm-21/bin/clang+0x12939)
#27 0x0000613bc38e65b5 (/usr/lib/llvm-21/bin/clang+0xf5b5)
#28 0x00007c46457622a9 (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x23692a9)
#29 0x00007c463b997fb8 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/usr/lib/llvm-21/bin/../lib/libLLVM.so.21.1+0xb01fb8)
#30 0x00007c4645761c2d clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x2368c2d)
#31 0x00007c464572488e clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x232b88e)
#32 0x00007c4645724a4e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x232ba4e)
#33 0x00007c46457437bd clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/usr/lib/llvm-21/bin/../lib/libclang-cpp.so.21.1+0x234a7bd)
#34 0x0000613bc38e6098 clang_main(int, char**, llvm::ToolContext const&) (/usr/lib/llvm-21/bin/clang+0xf098)
#35 0x0000613bc38f3e06 main (/usr/lib/llvm-21/bin/clang+0x1ce06)
#36 0x00007c463a9bb24a (/lib/x86_64-linux-gnu/libc.so.6+0x2724a)
#37 0x00007c463a9bb305 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x27305)
#38 0x0000613bc38e42d1 _start (/usr/lib/llvm-21/bin/clang+0xd2d1)
clang: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Debian clang version 21.1.5 (++20251023083151+45afac62e373-1~exp1~20251023083333.51)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-21/bin
clang: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/test-184795.c
clang: note: diagnostic msg: /tmp/test-184795.sh
clang: note: diagnostic msg:
********************
```
[test-184795.c](https://github.com/user-attachments/files/25080865/test-184795.c)
[test-184795.sh](https://github.com/user-attachments/files/25080866/test-184795.sh)
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