[OpenMP] No long crash on an invalid sizes argument

[AaronBallman]

We were trying to get type information out of an expression node which contained errors. That causes the type of the expression to be dependent, which the code was not expecting. Now we handle error conditions with an early return.

Fixes #139073

[llvmbot]

@llvm/pr-subscribers-openmp

@llvm/pr-subscribers-clang

Author: Aaron Ballman (AaronBallman)

Changes

We were trying to get type information out of an expression node which contained errors. That causes the type of the expression to be dependent, which the code was not expecting. Now we handle error conditions with an early return.

Fixes #139073

---

Full diff: https://github.com/llvm/llvm-project/pull/139118.diff

3 Files Affected:

• (modified) clang/docs/ReleaseNotes.rst (+2)
• (modified) clang/lib/Sema/SemaOpenMP.cpp (+12-2)
• (modified) clang/test/OpenMP/tile_messages.cpp (+9)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7f68fd877e4e2..e6d7a19051965 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -891,6 +891,8 @@ OpenMP Support
 - Added support 'no_openmp_constructs' assumption clause.
 - Added support for 'self_maps' in map and requirement clause.
 - Added support for 'omp stripe' directive.
+- Fixed a crashing bug with ``omp tile sizes`` if the argument to ``sizes`` was
+  an invalid expression. (#GH139073)
 
 Improvements
 ^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 835dba22a858d..2534822b72f80 100644
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -14328,6 +14328,10 @@ StmtResult SemaOpenMP::ActOnOpenMPTileDirective(ArrayRef<OMPClause *> Clauses,
   auto MakeDimTileSize = [&SemaRef = this->SemaRef, &CopyTransformer, &Context,
                           SizesClause, CurScope](int I) -> Expr * {
     Expr *DimTileSizeExpr = SizesClause->getSizesRefs()[I];
+
+    if (DimTileSizeExpr->containsErrors())
+      return nullptr;
+
     if (isa<ConstantExpr>(DimTileSizeExpr))
       return AssertSuccess(CopyTransformer.TransformExpr(DimTileSizeExpr));
 
@@ -14397,10 +14401,13 @@ StmtResult SemaOpenMP::ActOnOpenMPTileDirective(ArrayRef<OMPClause *> Clauses,
 
     // For cond-expression:
     //   .tile.iv < min(.floor.iv + DimTileSize, NumIterations)
+    Expr *DimTileSize = MakeDimTileSize(I);
+    if (!DimTileSize)
+      return StmtError();
     ExprResult EndOfTile = SemaRef.BuildBinOp(
         CurScope, LoopHelper.Cond->getExprLoc(), BO_Add,
         makeFloorIVRef(SemaRef, FloorIndVars, I, IVTy, OrigCntVar),
-        MakeDimTileSize(I));
+        DimTileSize);
     if (!EndOfTile.isUsable())
       return StmtError();
     ExprResult IsPartialTile =
@@ -14482,10 +14489,13 @@ StmtResult SemaOpenMP::ActOnOpenMPTileDirective(ArrayRef<OMPClause *> Clauses,
       return StmtError();
 
     // For incr-statement: .floor.iv += DimTileSize
+    Expr *DimTileSize = MakeDimTileSize(I);
+    if (!DimTileSize)
+      return StmtError();
     ExprResult IncrStmt = SemaRef.BuildBinOp(
         CurScope, LoopHelper.Inc->getExprLoc(), BO_AddAssign,
         makeFloorIVRef(SemaRef, FloorIndVars, I, IVTy, OrigCntVar),
-        MakeDimTileSize(I));
+        DimTileSize);
     if (!IncrStmt.isUsable())
       return StmtError();
 
diff --git a/clang/test/OpenMP/tile_messages.cpp b/clang/test/OpenMP/tile_messages.cpp
index 5268dfe97e0c8..e1f5155c924e5 100644
--- a/clang/test/OpenMP/tile_messages.cpp
+++ b/clang/test/OpenMP/tile_messages.cpp
@@ -161,3 +161,12 @@ void template_inst() {
   // expected-note@+1 {{in instantiation of function template specialization 'templated_func_type_dependent<int>' requested here}}
   templated_func_type_dependent<int>();
 }
+
+namespace GH139073 {
+void f(void) {
+  // Clang would previously crash on this because of the invalid DeclRefExpr.
+#pragma omp tile sizes(a) // expected-error {{use of undeclared identifier 'a'}}
+  for (int i = 0; i < 10; i++)
+    ;
+}
+} // namespace GH139073