@@ -560,29 +560,33 @@
 
 	return (IMP)nil;
 }
 
 Class
-object_getClass(id obj)
+object_getClass(id obj_)
 {
+	struct objc_object *obj = (struct objc_object*)obj_;
+
 	return obj->isa;
 }
 
 Class
-object_setClass(id obj, Class cls)
+object_setClass(id obj_, Class cls)
 {
-	Class old = obj->isa;
+	struct objc_object *obj = (struct objc_object*)obj_;
+	Class old;
 
+	old = obj->isa;
 	obj->isa = cls;
 
 	return old;
 }
 
 const char*
 object_getClassName(id obj)
 {
-	return obj->isa->name;
+	return object_getClass(obj)->name;
 }
 
 static void
 free_class(Class rcls)
 {