================
@@ -8663,31 +8663,95 @@ static const RecordDecl
*GetEnclosingNamedOrTopAnonRecord(const FieldDecl *FD) {
return RD;
}
-static bool
-CheckCountExpr(Sema &S, FieldDecl *FD, Expr *E,
- llvm::SmallVectorImpl<TypeCoupledDeclRefInfo> &Decls) {
+enum class CountedByInvalidPointeeTypeKind {
+ INCOMPLETE,
+ SIZELESS,
+ FUNCTION,
+ FLEXIBLE_ARRAY_MEMBER,
+ VALID,
+};
+
+static bool CheckCountedByAttrOnField(
+ Sema &S, FieldDecl *FD, Expr *E,
+ llvm::SmallVectorImpl<TypeCoupledDeclRefInfo> &Decls) {
+ // Check the context the attribute is used in
+
if (FD->getParent()->isUnion()) {
S.Diag(FD->getBeginLoc(), diag::err_counted_by_attr_in_union)
<< FD->getSourceRange();
return true;
}
- if (!E->getType()->isIntegerType() || E->getType()->isBooleanType()) {
- S.Diag(E->getBeginLoc(), diag::err_counted_by_attr_argument_not_integer)
- << E->getSourceRange();
+ const auto FieldTy = FD->getType();
+ if (!FieldTy->isArrayType() && !FieldTy->isPointerType()) {
+ S.Diag(FD->getBeginLoc(),
+ diag::err_counted_by_attr_not_on_ptr_or_flexible_array_member)
+ << FD->getLocation();
return true;
}
LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel =
LangOptions::StrictFlexArraysLevelKind::IncompleteOnly;
-
- if (!Decl::isFlexibleArrayMemberLike(S.getASTContext(), FD, FD->getType(),
+ if (FieldTy->isArrayType() &&
+ !Decl::isFlexibleArrayMemberLike(S.getASTContext(), FD, FieldTy,
StrictFlexArraysLevel, true)) {
- // The "counted_by" attribute must be on a flexible array member.
- SourceRange SR = FD->getLocation();
- S.Diag(SR.getBegin(),
- diag::err_counted_by_attr_not_on_flexible_array_member)
- << SR;
+ S.Diag(FD->getBeginLoc(),
+ diag::err_counted_by_attr_on_array_not_flexible_array_member)
----------------
hnrklssn wrote:
I believe the question is not why only flexible array members are allowed the
attribute, but why only incomplete arrays are. Some old projects use this as
syntax as incomplete array:
```
struct S {
int len;
char fam[0];
};
```
Would converting the above to an incomplete array like this be an issue in
those projects? It seems to me that if you're introducing `__counted_by`,
removing any old integer constant isn't much more extra work.
```
struct S {
int len;
char fam[__counted_by(len)];
};
```
The reason is that a complete array already has a bound, which we use for
bounds checking with `-fbounds-safety` enabled. In fact, an array parameter
like this will decay into a `int * __counted_by(len)` pointer:
```
void foo(int len, int arr[len]);
```
If you allow annotating these arrays with `__counted_by` also, you effectively
end up with two separate sources of bounds info.
https://github.com/llvm/llvm-project/pull/93121
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