Add clarifying comments; Fix empty diagostic text; Use ArrayRef for parameter

Author: rapidsna

clang/include/clang/Parse/Parser.h

@@ -1164,8 +1164,8 @@ class Parser : public CodeCompletionHandler {
     unsigned NestedTypeLevel;
 
     explicit LateParsedAttribute(Parser *P, IdentifierInfo &Name,
-                                 SourceLocation Loc, unsigned Level = 0)
-        : Self(P), AttrName(Name), AttrNameLoc(Loc), NestedTypeLevel(Level) {}
+                                 SourceLocation Loc, unsigned NestedTypeLevel = 0)
+        : Self(P), AttrName(Name), AttrNameLoc(Loc), NestedTypeLevel(NestedTypeLevel) {}
 
     void ParseLexedAttributes() override;
 

clang/include/clang/Sema/DeclSpec.h

@@ -1238,7 +1238,11 @@ struct DeclaratorChunk {
 
   ParsedAttributesView AttrList;
 
-  using LateAttrListTy = SmallVector<void *, 1>;
+  /// Stores pointers to `Parser::LateParsedAttribute`. We use `void*` here
+  /// because `LateParsedAttribute` is a nested struct of `class Parser` and
+  /// cannot be forward-declared.
+  using LateAttrOpaquePtr = void *;
+  using LateAttrListTy = SmallVector<LateAttrOpaquePtr, 1>;
   LateAttrListTy LateAttrList;
 
   struct PointerTypeInfo {
@@ -2329,7 +2333,7 @@ class Declarator {
   /// of those attributes from the parameter.
   void AddTypeInfo(const DeclaratorChunk &TI, ParsedAttributes &&attrs,
                    SourceLocation EndLoc,
-                   const DeclaratorChunk::LateAttrListTy &LateAttrs = {}) {
+                   ArrayRef<DeclaratorChunk::LateAttrOpaquePtr> LateAttrs = {}) {
     DeclTypeInfo.push_back(TI);
     DeclTypeInfo.back().getAttrs().prepend(attrs.begin(), attrs.end());
     getAttributePool().takeAllFrom(attrs.getPool());

clang/lib/Parse/ParseDecl.cpp

@@ -3145,7 +3145,7 @@ void Parser::DistributeCLateParsedAttrs(Declarator &D, Decl *Dcl,
   if (!LateAttrs)
     return;
 
-  unsigned NestedLevel = 0;
+  unsigned NestedTypeLevel = 0;
   for (unsigned i = 0; i < D.getNumTypeObjects(); ++i) {
     DeclaratorChunk &DC = D.getTypeObject(i);
 
@@ -3160,10 +3160,10 @@ void Parser::DistributeCLateParsedAttrs(Declarator &D, Decl *Dcl,
     // Extract `LateParsedAttribute *` from `DeclaratorChunk`.
     for (auto *OpaqueLA : DC.LateAttrList) {
       auto *LA = static_cast<LateParsedAttribute *>(OpaqueLA);
-      LA->NestedTypeLevel = NestedLevel;
+      LA->NestedTypeLevel = NestedTypeLevel;
       LateAttrs->push_back(LA);
     }
-    NestedLevel++;
+    NestedTypeLevel++;
   }
 
   // Attach `Decl *` to each `LateParsedAttribute *`.
@@ -6484,8 +6484,10 @@ void Parser::ParseDeclaratorInternal(Declarator &D,
     if (Kind == tok::star) {
       DeclaratorChunk::LateAttrListTy OpaqueLateAttrList;
       if (getLangOpts().ExperimentalLateParseAttributes && !LateAttrs.empty()) {
+        // TODO: Support `counted_by` in function parameters, return types, and
+        // other contexts (Issue #167365).
         if (!D.isFunctionDeclarator()) {
-          for (auto LA : LateAttrs) {
+          for (LateParsedAttribute *LA : LateAttrs) {
             OpaqueLateAttrList.push_back(LA);
           }
         }

clang/test/Sema/attr-sized-by-late-parsed-struct-ptrs.c

@@ -102,9 +102,6 @@ struct on_pointer_anon_count {
 //==============================================================================
 // __sized_by on struct member pointer in type attribute position
 //==============================================================================
-// TODO: Correctly parse sized_by as a type attribute. Currently it is parsed
-// as a declaration attribute and is **not** late parsed resulting in the `size`
-// field being unavailable.
 
 struct on_member_pointer_complete_ty_ty_pos {
   struct size_known *__sized_by(size) buf;
@@ -156,7 +153,7 @@ struct on_member_pointer_fn_ptr_ty_typedef_ty_pos {
 };
 
 struct on_member_pointer_fn_ptr_ty_ty_pos_inner {
-  // expected-error@+1{{}}
+  // expected-error@+1{{'sized_by' attribute on nested pointer type is not allowed}}
   void (* __sized_by(size) * fn_ptr)(void);
   int size;
 };
@@ -174,9 +171,7 @@ struct on_member_pointer_struct_with_annotated_vla_ty_pos {
 };
 
 struct on_nested_pointer_inner {
-  // TODO: This should be disallowed because in the `-fbounds-safety` model
-  // `__sized_by` can only be nested when used in function parameters.
-  // expected-error@+1{{}}
+  // expected-error@+1{{'sized_by' attribute on nested pointer type is not allowed}}
   struct size_known *__sized_by(size) *buf;
   int size;
 };

clang/test/Sema/attr-sized-by-or-null-late-parsed-struct-ptrs.c

@@ -136,6 +136,7 @@ struct on_member_pointer_fn_ptr_ty_ptr_ty_pos {
 };
 
 struct on_member_pointer_fn_ty_ty_pos {
+  // TODO: Improve diagnostics (Issue #167368).
   // expected-error@+1{{'sized_by_or_null' cannot be applied to a pointer with pointee of unknown size because 'void (void)' is a function type}}
   void (* __sized_by_or_null(size) fn_ptr)(void);
   int size;