================
@@ -17432,16 +17457,54 @@ OMPClause
*SemaOpenMP::ActOnOpenMPSizesClause(ArrayRef<Expr *> SizeExprs,
SourceLocation StartLoc,
SourceLocation LParenLoc,
SourceLocation EndLoc) {
- for (Expr *SizeExpr : SizeExprs) {
- ExprResult NumForLoopsResult = VerifyPositiveIntegerConstantInClause(
- SizeExpr, OMPC_sizes, /*StrictlyPositive=*/true);
- if (!NumForLoopsResult.isUsable())
- return nullptr;
+ SmallVector<Expr *> SanitizedSizeExprs;
+ llvm::append_range(SanitizedSizeExprs, SizeExprs);
+
+ for (Expr *&SizeExpr : SanitizedSizeExprs) {
+ // Skip if already sanitized, e.g. during a partial template instantiation.
+ if (!SizeExpr)
+ continue;
+
+ bool IsValid = isNonNegativeIntegerValue(SizeExpr, SemaRef, OMPC_sizes,
+ /*StrictlyPositive=*/true);
+
+ // isNonNegativeIntegerValue returns true for non-integral types (but still
+ // emits error diagnostic), so check for the expected type explicitly.
+ QualType SizeTy = SizeExpr->getType();
+ if (!SizeTy->isIntegerType())
+ IsValid = false;
+
+ // Handling in templates is tricky. There are four possibilities to
+ // consider:
+ //
+ // 1a. The expression is valid and we are in a instantiated template or not
+ // in a template:
+ // Pass valid expression to be further analysed later in Sema.
+ // 1b. The expression is valid and we are in a template (including partial
+ // instantiation):
+ // isNonNegativeIntegerValue skipped any checks so there is no
+ // guarantee it will be correct after instantiation.
+ // ActOnOpenMPSizesClause will be called again at instantiation when
+ // it is not in a dependent context anymore. This may cause warnings
+ // to be emitted multiple times.
+ // 2a. The expression is invalid and we are in an instantiated template or
+ // not in a template:
+ // Invalidate the expression with a clearly wrong value (nullptr) so
+ // later in Sema we do not have to do the same validity analysis
again
+ // or crash from unexpected data. Error diagnostics have already been
+ // emitted.
+ // 2b. The expression is invalid and we are in a template (including
partial
+ // instantiation):
+ // Pass the invalid expression as-is, template instantiation may
+ // replace unexpected types/values with valid ones. The directives
+ // with this clause must not try to use these expressions in
dependent
+ // contexts.
----------------
Meinersbur wrote:
Case 2b is already adhered to in `ActOnOpenMPTileDirective`:
```
// Delay tiling to when template is completely instantiated.
if (SemaRef.CurContext->isDependentContext())
return OMPTileDirective::Create(Context, StartLoc, EndLoc, Clauses,
NumLoops, AStmt, nullptr, nullptr);
```
Delaying further analysis seems generally to be what OpenMP does, e.g.
```
isNonNegativeIntegerValue(...) {
if (!ValExpr->isTypeDependent() && !ValExpr->isValueDependent() &&
!ValExpr->isInstantiationDependent()) {
```
https://github.com/llvm/llvm-project/pull/91345
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