================
@@ -186,4 +218,216 @@ bool Sema::CheckCountedByAttrOnField(FieldDecl *FD, Expr
*E, bool CountInBytes,
return false;
}
+SourceRange Sema::BoundsSafetySourceRangeFor(const CountAttributedType *CATy) {
+ // This is an approximation that's not quite right. This points to the
+ // the expression inside the attribute rather than the attribute itself.
+ //
+ // TODO: Implement logic to find the relevant TypeLoc for the attribute and
+ // get the SourceRange from that (#113582).
+ return CATy->getCountExpr()->getSourceRange();
+}
+
+static void EmitIncompleteCountedByPointeeNotes(Sema &S,
+ const CountAttributedType
*CATy,
+ NamedDecl *IncompleteTyDecl,
+ bool NoteAttrLocation = true) {
+ assert(IncompleteTyDecl == nullptr || isa<TypeDecl>(IncompleteTyDecl));
+
+ if (NoteAttrLocation) {
+ // Note where the attribute is declared
+ auto AttrSrcRange = S.BoundsSafetySourceRangeFor(CATy);
+ S.Diag(AttrSrcRange.getBegin(), diag::note_named_attribute)
+ << CATy->getAttributeName(/*WithMacroPrefix=*/true) << AttrSrcRange;
+ }
+
+ if (!IncompleteTyDecl)
+ return;
+
+ // If there's an associated forward declaration display it to emphasize
+ // why the type is incomplete (all we have is a forward declaration).
+
+ // Note the `IncompleteTyDecl` type is the underlying type which might not
+ // be the same as `CATy->getPointeeType()` which could be a typedef.
+ //
+ // The diagnostic printed will be at the location of the underlying type but
+ // the diagnostic text will print the type of `CATy->getPointeeType()` which
+ // could be a typedef name rather than the underlying type. This is ok
+ // though because the diagnostic will print the underlying type name too.
+ // E.g:
+ //
+ // `forward declaration of 'Incomplete_Struct_t'
+ // (aka 'struct IncompleteStructTy')`
+ //
+ // If this ends up being confusing we could emit a second diagnostic (one
+ // explaining where the typedef is) but that seems overly verbose.
+
+ S.Diag(IncompleteTyDecl->getBeginLoc(), diag::note_forward_declaration)
+ << CATy->getPointeeType();
+}
+
+static bool
+HasCountedByAttrOnIncompletePointee(QualType Ty, NamedDecl **ND,
+ const CountAttributedType **CATyOut,
+ QualType *PointeeTyOut) {
+ auto *CATy = Ty->getAs<CountAttributedType>();
+ if (!CATy)
+ return false;
+
+ // Incomplete pointee type is only a problem for
+ // counted_by/counted_by_or_null
+ if (CATy->isCountInBytes())
+ return false;
+
+ auto PointeeTy = CATy->getPointeeType();
+ if (PointeeTy.isNull())
+ return false; // Reachable?
+
+ if (!PointeeTy->isIncompleteType(ND))
+ return false;
+
+ if (CATyOut)
+ *CATyOut = CATy;
+ if (PointeeTyOut)
+ *PointeeTyOut = PointeeTy;
+ return true;
+}
+
+/// Perform Checks for assigning to a `__counted_by` or
+/// `__counted_by_or_null` pointer type \param LHSTy where the pointee type
+/// is incomplete which is invalid.
+///
+/// \param S The Sema instance.
+/// \param LHSTy The type being assigned to. Checks will only be performed if
+/// the type is a `counted_by` or `counted_by_or_null ` pointer.
+/// \param RHSExpr The expression being assigned from.
+/// \param Action The type assignment being performed
+/// \param Loc The SourceLocation to use for error diagnostics
+/// \param ComputeAssignee If provided this function will be called before
+/// emitting a diagnostic. The function should return the name of
+/// entity being assigned to or an empty string if this cannot be
+/// determined.
+///
+/// \returns True iff no diagnostic where emitted, false otherwise.
+static bool CheckAssignmentToCountAttrPtrWithIncompletePointeeTy(
+ Sema &S, QualType LHSTy, Expr *RHSExpr, AssignmentAction Action,
+ SourceLocation Loc, llvm::function_ref<std::string()> ComputeAssignee) {
----------------
delcypher wrote:
> All the uses I saw at least end up passing in the name of some declaration—or
> are there cases where we need/want to pass in some other string?
* So in some cases there isn't a named assignee. This is the case for return
values as can be seen
[here](https://github.com/swiftlang/llvm-project/blob/b0bbd7e8a003990aff9ce373bc6b83407630b5f5/clang/lib/Sema/SemaChecking.cpp#L9505).
This is also the case for unnamed parameters as can be seen
[here](https://github.com/swiftlang/llvm-project/blob/b0bbd7e8a003990aff9ce373bc6b83407630b5f5/clang/lib/Sema/SemaBoundsSafety.cpp#L640)
* In some cases we want the fully qualified name of a field in the struct. You
can see this
[here](https://github.com/swiftlang/llvm-project/blob/b0bbd7e8a003990aff9ce373bc6b83407630b5f5/clang/lib/Sema/SemaBoundsSafety.cpp#L537)
for initializer lists and
[here](https://github.com/swiftlang/llvm-project/blob/b0bbd7e8a003990aff9ce373bc6b83407630b5f5/clang/lib/Sema/SemaExpr.cpp#L16743)
for assignment expressions
The reason the function takes a `function_ref` is I realized it was pretty
wasteful to always allocate a `std::string` and compute it in the cases where
the diagnostic is not emitted (the common case). So by making the allocation
and computation of the string a `function_ref` this can be performed **only in
the case that the diagnostic is emitted**.
That being said it might be possible to replace the `function_ref` by instead
passing a `std::optional<clang::NamedDecl>` instead. I'll need to investigate
if I can make this work correclty.
https://github.com/llvm/llvm-project/pull/106321
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
