Disable retain-count tracking for references to OSMetaClass

[georgi_igna]

There is an existing revision that I can use for this change

clang/lib/Analysis/RetainSummaryManager.cpp

 static bool isSubclass(const Decl *D,
                        StringRef ClassName) {
   using namespace ast_matchers;
   DeclarationMatcher SubclassM =
       cxxRecordDecl(isSameOrDerivedFrom(std::string(ClassName)));
   return !(match(SubclassM, *D, D->getASTContext()).empty());
 }
 
-static bool isOSObjectSubclass(const Decl *D) {
-  return D && isSubclass(D, "OSMetaClassBase");
+static bool isExactClass(const Decl *D, StringRef ClassName) {
+  using namespace ast_matchers;
+  DeclarationMatcher sameClassM =
+      cxxRecordDecl(hasName(std::string(ClassName)));
+  return !(match(sameClassM, *D, D->getASTContext()).empty());
 }
 
-static bool isOSObjectDynamicCast(StringRef S) {
-  return S == "safeMetaCast";
+static bool isOSObjectSubclass(const Decl *D) {
+  return D && isSubclass(D, "OSMetaClassBase") &&
+         !isExactClass(D, "OSMetaClass");
 }
 
+static bool isOSObjectDynamicCast(StringRef S) { return S == "safeMetaCast"; }
+
 static bool isOSObjectRequiredCast(StringRef S) {
   return S == "requiredMetaCast";
 }
 
 static bool isOSObjectThisCast(StringRef S) {
   return S == "metaCast";
 }
 

clang/test/Analysis/os_object_base.h

struct OSObject : public OSMetaClassBase {
   static void * operator new(size_t size);
 
   static const OSMetaClass * const metaClass;
 };
 
 struct OSMetaClass : public OSMetaClassBase {
   virtual OSObject * alloc() const;
   static OSObject * allocClassWithName(const char * name);
+  static const OSMetaClass * copyMetaClassWithName(const char * name);
+  void releaseMetaClass() const;
   virtual ~OSMetaClass(){}
 };
 
 struct OSCollection: OSObject {};
 
 #endif /* _OS_BASE_H */

clang/test/Analysis/osobject-retain-release.cpp

 void test_smart_ptr_no_leak() {
   OSObject *obj = new OSObject;
   {
     OSObjectPtr p(obj);
   }
   obj->release();
 }
 
+void test_osmetaclass_release(){
+    const char *name = "no_name";
+    const OSMetaClass *meta = OSMetaClass::copyMetaClassWithName(name);
+    if (!meta) {
+        return;
+    } else {
+        meta->releaseMetaClass();
+    }
+}
+
 class SampleClass {
 public:
   OSObjectPtr field;
 
   void methodFieldConsumes() {
     OSObject *a = new OSObject;
     field = OSObjectPtr(a, os::no_retain);
   }