https://github.com/nataliakokoromyti created https://github.com/llvm/llvm-project/pull/179368
We were getting a segfault when using asm goto with an undeclared label inside an OpenMP pragma (see issue #179238). The issue was that when you have an undeclared label in an OpenMP scope, Target (which is a LabelDecl*) can be null. The code was just assuming it was always valid and dereferencing it without checking. Just adding a null check before using Target fixes it. Still reports the errors (undeclared label, invalid jump, etc.) but doesn't segfault. >From cc1c58a8e75cbcfadc6d586a199fe7a2a29d025e Mon Sep 17 00:00:00 2001 From: nataliakokoromyti <[email protected]> Date: Mon, 2 Feb 2026 17:42:23 -0800 Subject: [PATCH] [Clang][Sema] Fix crash with asm goto and OpenMP pragma --- clang/lib/Sema/JumpDiagnostics.cpp | 3 ++- clang/test/Sema/openmp-asm-goto-crash.c | 11 +++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) create mode 100644 clang/test/Sema/openmp-asm-goto-crash.c diff --git a/clang/lib/Sema/JumpDiagnostics.cpp b/clang/lib/Sema/JumpDiagnostics.cpp index 2c45de69e7cdf..f7bc8dea5fa75 100644 --- a/clang/lib/Sema/JumpDiagnostics.cpp +++ b/clang/lib/Sema/JumpDiagnostics.cpp @@ -916,7 +916,8 @@ static void DiagnoseIndirectOrAsmJumpStmt(Sema &S, Stmt *Jump, bool IsAsmGoto = isa<GCCAsmStmt>(Jump); S.Diag(Jump->getBeginLoc(), diag::err_indirect_goto_in_protected_scope) << IsAsmGoto; - S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target) + if (Target && Target->getStmt()) + S.Diag(Target->getStmt()->getIdentLoc(), diag::note_indirect_goto_target) << IsAsmGoto; Diagnosed = true; } diff --git a/clang/test/Sema/openmp-asm-goto-crash.c b/clang/test/Sema/openmp-asm-goto-crash.c new file mode 100644 index 0000000000000..7429573b4c2db --- /dev/null +++ b/clang/test/Sema/openmp-asm-goto-crash.c @@ -0,0 +1,11 @@ +// RUN: %clang_cc1 -fopenmp -fsyntax-only -verify -triple x86_64-unknown-linux-gnu %s + +int test_asm_goto_undeclared_label() { +#pragma omp assume + __asm__ goto("" : : : : undefined_label); // expected-error {{use of undeclared label 'undefined_label'}} \ + // expected-error {{cannot jump from this asm goto statement to one of its possible targets}} \ + // expected-note {{jump exits scope of OpenMP structured block}} + int x = 1; +undefined_label: + return x; +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
