| Issue |
179238
|
| Summary |
clang segmentation fault with -fopenmp and asm goto
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
iamanonymouscs
|
clang segmentation fault with `-fopenmp` and `asm goto`
Compiler explorer (assertion trunk): https://godbolt.org/z/TMbGbx37r
```
$ cat small.c
int main() {
#pragma omp assume
__asm__ goto("" : : : : a);
int b = 1;
a:
}
```
```
$ clang-trunk -fopenmp small.c -c
<source>:3:27: error: use of undeclared label 'a'
3 | __asm__ goto("" : : : : a);
| ^
<source>:6:1: warning: label at end of compound statement is a C23 extension [-Wc23-extensions]
6 | }
| ^
<source>:3:3: error: cannot jump from this asm goto statement to one of its possible targets
3 | __asm__ goto("" : : : : a);
| ^
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: /cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir /app/output.s- -disable-free -clear-ast-before-backend -main-file-name example.c -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -fno-verbose-asm -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debug-info-kind=constructor -dwarf-version=5 -debugger-tuning=gdb -fdebug-compilation-dir=/app -fcoverage-compilation-dir=/app -resource-dir /cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/lib/clang/23 -internal-isystem /cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/lib/clang/23/include -internal-isystem /cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/../include/x86_64-unknown-linux-gnu -internal-isystem /usr/local/include -internal-isystem /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/16.0.1/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -ferror-limit 19 -fopenmp -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -faddrsig -fdwarf2-cfi-asm -o /tmp/example-68eacf.o -x c <source>
1. <eof> parser at end of file
2. <source>:1:12: parsing function body 'main'
#0 0x0000000004330f88 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x4330f88)
#1 0x000000000432de64 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#2 0x0000732964642520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#3 0x00000000077a2cd3 DiagnoseIndirectOrAsmJumpStmt(clang::Sema&, clang::Stmt*, clang::LabelDecl*, bool&) (.part.0) JumpDiagnostics.cpp:0:0
#4 0x00000000077a51a3 (anonymous namespace)::JumpScopeChecker::DiagnoseIndirectOrAsmJump(clang::Stmt*, unsigned int, clang::LabelDecl*, unsigned int) JumpDiagnostics.cpp:0:0
#5 0x00000000077a7c6f clang::Sema::DiagnoseInvalidJumps(clang::Stmt*) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x77a7c6f)
#6 0x0000000006eaaf72 clang::Sema::ActOnFinishFunctionBody(clang::Decl*, clang::Stmt*, bool, bool) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6eaaf72)
#7 0x0000000006bc60a4 clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6bc60a4)
#8 0x0000000006acb8eb clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6acb8eb)
#9 0x0000000006b01d9d clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, clang::DeclaratorContext, clang::ParsedAttributes&, clang::Parser::ParsedTemplateInfo&, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6b01d9d)
#10 0x0000000006abe9bb clang::Parser::ParseDeclOrFunctionDefInternal(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6abe9bb)
#11 0x0000000006abf1af clang::Parser::ParseDeclarationOrFunctionDefinition(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6abf1af)
#12 0x0000000006ac71b1 clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6ac71b1)
#13 0x0000000006ac80c5 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6ac80c5)
#14 0x0000000006ac84b0 clang::Parser::ParseFirstTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6ac84b0)
#15 0x0000000006aa8da3 clang::ParseAST(clang::Sema&, bool, bool) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x6aa8da3)
#16 0x0000000004ca0d58 clang::CodeGenAction::ExecuteAction() (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x4ca0d58)
#17 0x0000000004f9d575 clang::FrontendAction::Execute() (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x4f9d575)
#18 0x0000000004f1cd0e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x4f1cd0e)
#19 0x000000000509869d clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0x509869d)
#20 0x0000000000de144e cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0xde144e)
#21 0x0000000000dd7e1a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>) driver.cpp:0:0
#22 0x0000000000ddc228 clang_main(int, char**, llvm::ToolContext const&) (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0xddc228)
#23 0x0000000000c997b4 main (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0xc997b4)
#24 0x0000732964629d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#25 0x0000732964629e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#26 0x0000000000dd78b5 _start (/cefs/e8/e865498113d226505147d317_clang-assertions-trunk-20260202/bin/clang-23+0xdd78b5)
clang: error: unable to execute command: Segmentation fault (core dumped)
clang: error: clang frontend command failed due to signal (use -v to see invocation)
Compiler returned: 254
```
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