[ASTMatchers] AST matcher support for ObjC pointers (#117021)

Add `ObjCInterfaceDecl` to the list of types supported by the `hasType`
and `hasDeclaration` matchers, `ObjCObjectPointerType` to the list of
types supported by `pointee`.
These AST matcher improvements will help the new WebKit checker for
unsafe casts
([https://github.com/llvm/llvm-project/pull/114606](https://github.com/llvm/llvm-project/pull/114606))
match on unsafe Objective-C pointer casts.

Author: t-rasmud

clang/docs/ReleaseNotes.rst

@@ -975,6 +975,10 @@ AST Matchers
 
 - Add ``exportDecl`` matcher to match export declaration.
 
+- Ensure ``hasType`` and ``hasDeclaration`` match Objective-C interface declarations.
+
+- Ensure ``pointee`` matches Objective-C pointer types.
+
 clang-format
 ------------
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -4044,7 +4044,7 @@ AST_POLYMORPHIC_MATCHER_P_OVERLOAD(
 AST_POLYMORPHIC_MATCHER_P_OVERLOAD(
     hasType,
     AST_POLYMORPHIC_SUPPORTED_TYPES(Expr, FriendDecl, ValueDecl,
-                                    CXXBaseSpecifier),
+                                    CXXBaseSpecifier, ObjCInterfaceDecl),
     internal::Matcher<Decl>, InnerMatcher, 1) {
   QualType QT = internal::getUnderlyingType(Node);
   if (!QT.isNull())
@@ -7445,7 +7445,8 @@ extern const AstTypeMatcher<RValueReferenceType> rValueReferenceType;
 AST_TYPELOC_TRAVERSE_MATCHER_DECL(
     pointee, getPointee,
     AST_POLYMORPHIC_SUPPORTED_TYPES(BlockPointerType, MemberPointerType,
-                                    PointerType, ReferenceType));
+                                    PointerType, ReferenceType,
+                                    ObjCObjectPointerType));
 
 /// Matches typedef types.
 ///

clang/include/clang/ASTMatchers/ASTMatchersInternal.h

@@ -161,6 +161,9 @@ inline QualType getUnderlyingType(const FriendDecl &Node) {
 inline QualType getUnderlyingType(const CXXBaseSpecifier &Node) {
   return Node.getType();
 }
+inline QualType getUnderlyingType(const ObjCInterfaceDecl &Node) {
+  return Node.getTypeForDecl()->getPointeeType();
+}
 
 /// Unifies obtaining a `TypeSourceInfo` from different node types.
 template <typename T,
@@ -1113,6 +1116,11 @@ class HasDeclarationMatcher : public MatcherInterface<T> {
     return matchesDecl(Node.getDecl(), Finder, Builder);
   }
 
+  bool matchesSpecialized(const ObjCInterfaceDecl &Node, ASTMatchFinder *Finder,
+                          BoundNodesTreeBuilder *Builder) const {
+    return matchesDecl(Node.getCanonicalDecl(), Finder, Builder);
+  }
+
   /// Extracts the operator new of the new call and returns whether the
   /// inner matcher matches on it.
   bool matchesSpecialized(const CXXNewExpr &Node,
@@ -1213,7 +1221,7 @@ using HasDeclarationSupportedTypes =
              ElaboratedType, InjectedClassNameType, LabelStmt, AddrLabelExpr,
              MemberExpr, QualType, RecordType, TagType,
              TemplateSpecializationType, TemplateTypeParmType, TypedefType,
-             UnresolvedUsingType, ObjCIvarRefExpr>;
+             UnresolvedUsingType, ObjCIvarRefExpr, ObjCInterfaceDecl>;
 
 /// A Matcher that allows binding the node it matches to an id.
 ///

clang/lib/ASTMatchers/ASTMatchersInternal.cpp

@@ -1114,7 +1114,8 @@ AST_TYPELOC_TRAVERSE_MATCHER_DEF(hasValueType,
 AST_TYPELOC_TRAVERSE_MATCHER_DEF(
     pointee,
     AST_POLYMORPHIC_SUPPORTED_TYPES(BlockPointerType, MemberPointerType,
-                                    PointerType, ReferenceType));
+                                    PointerType, ReferenceType,
+                                    ObjCObjectPointerType));
 
 const internal::VariadicDynCastAllOfMatcher<Stmt, OMPExecutableDirective>
     ompExecutableDirective;

clang/unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

@@ -283,6 +283,12 @@ TEST(HasDeclaration, HasDeclarationOfTypeAlias) {
           hasDeclaration(typeAliasTemplateDecl()))))))));
 }
 
+TEST(HasDeclaration, HasDeclarationOfObjCInterface) {
+  EXPECT_TRUE(matchesObjC("@interface BaseClass @end void f() {BaseClass* b;}",
+                          varDecl(hasType(objcObjectPointerType(
+                              pointee(hasDeclaration(objcInterfaceDecl())))))));
+}
+
 TEST(HasUnqualifiedDesugaredType, DesugarsUsing) {
   EXPECT_TRUE(
       matches("struct A {}; using B = A; B b;",