[strong] weak classes can't inherit from strong ones

src/runtime/runtime-classes.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <stdlib.h>
 #include <limits>
 
 #include "src/arguments.h"
@@ skipping 120 matching lines @@
           isolate,
           NewTypeError(MessageTemplate::kExtendsValueNotFunction, super_class),
           Object);
     }
   }
 
   Handle<Map> map =
       isolate->factory()->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
   if (constructor->map()->is_strong()) {
     map->set_is_strong();
+    if (super_class->IsNull()) {
+      // Strong class is not permitted to extend null.
+      THROW_NEW_ERROR(isolate, NewTypeError(MessageTemplate::kStrongExtendNull),
+                      Object);
+    }
+  } else {
+    if (Handle<HeapObject>::cast(super_class)->map()->is_strong()) {
+      // Weak class is not permitted to extend strong class.
+      THROW_NEW_ERROR(isolate,
+                      NewTypeError(MessageTemplate::kStrongWeakExtend, name),
+                      Object);
+    }
   }
   Map::SetPrototype(map, prototype_parent);
   map->SetConstructor(*constructor);
   Handle<JSObject> prototype = isolate->factory()->NewJSObjectFromMap(map);
 
   Handle<String> name_string = name->IsString()
                                    ? Handle<String>::cast(name)
                                    : isolate->factory()->empty_string();
   constructor->shared()->set_name(*name_string);
 
@@ skipping 54 matching lines @@
   CONVERT_SMI_ARG_CHECKED(end_position, 4);
 
   Handle<Object> result;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, result, DefineClass(isolate, name, super_class, constructor,
                                    start_position, end_position));
   return *result;
 }
 
 
-RUNTIME_FUNCTION(Runtime_DefineClassStrong) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 5);
-  CONVERT_ARG_HANDLE_CHECKED(Object, name, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Object, super_class, 1);
-  CONVERT_ARG_HANDLE_CHECKED(JSFunction, constructor, 2);
-  CONVERT_SMI_ARG_CHECKED(start_position, 3);
-  CONVERT_SMI_ARG_CHECKED(end_position, 4);
-
-  if (super_class->IsNull()) {
-    THROW_NEW_ERROR_RETURN_FAILURE(
-        isolate, NewTypeError(MessageTemplate::kStrongExtendNull));
-  }
-
-  Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result, DefineClass(isolate, name, super_class, constructor,
-                                   start_position, end_position));
-  return *result;
-}
-
-
 RUNTIME_FUNCTION(Runtime_DefineClassMethod) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 3);
   CONVERT_ARG_HANDLE_CHECKED(JSObject, object, 0);
   CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, function, 2);
 
   RETURN_FAILURE_ON_EXCEPTION(isolate,
                               JSObject::DefinePropertyOrElementIgnoreAttributes(
                                   object, name, function, DONT_ENUM));
@@ skipping 311 matching lines @@
   Handle<Object> result;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, result,
       Execution::Call(isolate, reflect, isolate->factory()->undefined_value(),
                       arraysize(argv), argv));
 
   return *result;
 }
 }  // namespace internal
 }  // namespace v8