[ignition] Only initialize [[HomeObject]] for class constructors if needed

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/accessors.h"
@@ skipping 149 matching lines @@
 
   JSFunction::SetPrototype(constructor, prototype);
   PropertyAttributes attribs =
       static_cast<PropertyAttributes>(DONT_ENUM | DONT_DELETE | READ_ONLY);
   RETURN_ON_EXCEPTION(isolate,
                       JSObject::SetOwnPropertyIgnoreAttributes(
                           constructor, isolate->factory()->prototype_string(),
                           prototype, attribs),
                       Object);
 
-  // TODO(arv): Only do this conditionally.

[arv (Not doing code reviews), 2017/01/05 05:18:43]

Thanks

-  Handle<Symbol> home_object_symbol(isolate->heap()->home_object_symbol());
-  RETURN_ON_EXCEPTION(
-      isolate, JSObject::SetOwnPropertyIgnoreAttributes(
-                   constructor, home_object_symbol, prototype, DONT_ENUM),
-      Object);
-
   if (!constructor_parent.is_null()) {
     MAYBE_RETURN_NULL(JSObject::SetPrototype(constructor, constructor_parent,
                                              false, Object::THROW_ON_ERROR));
   }
 
   JSObject::AddProperty(prototype, isolate->factory()->constructor_string(),
                         constructor, DONT_ENUM);
 
   // Install private properties that are used to construct the FunctionToString.
   RETURN_ON_EXCEPTION(
       isolate,
       Object::SetProperty(
           constructor, isolate->factory()->class_start_position_symbol(),
           handle(Smi::FromInt(start_position), isolate), STRICT),
       Object);
   RETURN_ON_EXCEPTION(
       isolate, Object::SetProperty(
                    constructor, isolate->factory()->class_end_position_symbol(),
                    handle(Smi::FromInt(end_position), isolate), STRICT),
       Object);
 
-  return constructor;
+  // Caller already has access to constructor, so return the prototype.
+  return prototype;
 }
 
 
 RUNTIME_FUNCTION(Runtime_DefineClass) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 4);
   CONVERT_ARG_HANDLE_CHECKED(Object, super_class, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, constructor, 1);
   CONVERT_SMI_ARG_CHECKED(start_position, 2);
   CONVERT_SMI_ARG_CHECKED(end_position, 3);
@@ skipping 301 matching lines @@
   }
 
   // Call the constructor.
   RETURN_RESULT_OR_FAILURE(
       isolate, Execution::New(isolate, constructor, new_target, result_length,
                               construct_args.start()));
 }
 
 }  // namespace internal
 }  // namespace v8