[clang][OpenMP] Treat "workshare" as unknown OpenMP directive

[kparzysz]

The "workshare" construct is only present in Fortran. The common OpenMP code does treat it as any other directive, but in clang we need to reject it, and do so gracefully before it encounters an internal assertion.

Fixes #139424

[llvmbot]

@llvm/pr-subscribers-clang

Author: Krzysztof Parzyszek (kparzysz)

Changes

The "workshare" construct is only present in Fortran. The common OpenMP code does treat it as any other directive, but in clang we need to reject it, and do so gracefully before it encounters an internal assertion.

Fixes #139424

---

Full diff: https://github.com/llvm/llvm-project/pull/139793.diff

2 Files Affected:

• (modified) clang/lib/Parse/ParseOpenMP.cpp (+5)
• (added) clang/test/OpenMP/openmp_workshare.c (+8)

diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
index 85838feae77d3..2f4a1103cc3b3 100644
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -2738,6 +2738,11 @@ StmtResult Parser::ParseOpenMPDeclarativeOrExecutableDirective(
     Diag(Tok, diag::err_omp_unknown_directive);
     return StmtError();
   }
+  if (DKind == OMPD_workshare) {
+    // "workshare" is an executable, Fortran-only directive. Treat it
+    // as unknown.
+    DKind = OMPD_unknown;
+  }
 
   StmtResult Directive = StmtError();
 
diff --git a/clang/test/OpenMP/openmp_workshare.c b/clang/test/OpenMP/openmp_workshare.c
new file mode 100644
index 0000000000000..0302eb19f9ef4
--- /dev/null
+++ b/clang/test/OpenMP/openmp_workshare.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -verify -fopenmp -ferror-limit 100 -o - %s
+
+// Workshare is a Fortran-only directive.
+
+void foo() {
+#pragma omp workshare // expected-error {{expected an OpenMP directive}}
+}
+

[AaronBallman]

Thank you for the quick fix!