[OpenMP] No long crash on an invalid sizes argument (#139118)

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

Author: AaronBallman

clang/docs/ReleaseNotes.rst

@@ -901,6 +901,8 @@ 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
 ^^^^^^^^^^^^

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();
 

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