Free up 11 bits in fast-mode PropertyDetails by removing the enumeration-index.

src/bootstrapper.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2391 matching lines @@
   TransferObject(obj, object);
   return true;
 }
 
 
 void Genesis::TransferNamedProperties(Handle<JSObject> from,
                                       Handle<JSObject> to) {
   if (from->HasFastProperties()) {
     Handle<DescriptorArray> descs =
         Handle<DescriptorArray>(from->map()->instance_descriptors());
-    for (int i = 0; i < descs->number_of_descriptors(); i++) {
+    for (int i = 0; i < from->map()->NumberOfOwnDescriptors(); i++) {
       PropertyDetails details = descs->GetDetails(i);
       switch (details.type()) {
         case FIELD: {
           HandleScope inner(isolate());
           Handle<Name> key = Handle<Name>(descs->GetKey(i));
           int index = descs->GetFieldIndex(i);
           Handle<Object> value = Handle<Object>(from->FastPropertyAt(index),
                                                 isolate());
           CHECK_NOT_EMPTY_HANDLE(isolate(),
                                  JSObject::SetLocalPropertyIgnoreAttributes(
@@ skipping 13 matching lines @@
         case CALLBACKS: {
           LookupResult result(isolate());
           to->LocalLookup(descs->GetKey(i), &result);
           // If the property is already there we skip it
           if (result.IsFound()) continue;
           HandleScope inner(isolate());
           ASSERT(!to->HasFastProperties());
           // Add to dictionary.
           Handle<Name> key = Handle<Name>(descs->GetKey(i));
           Handle<Object> callbacks(descs->GetCallbacksObject(i), isolate());
-          PropertyDetails d = PropertyDetails(details.attributes(),
-                                              CALLBACKS,
-                                              Representation::Tagged(),
-                                              details.descriptor_index());
+          PropertyDetails d = PropertyDetails(
+              details.attributes(), CALLBACKS, i + 1);
           JSObject::SetNormalizedProperty(to, key, callbacks, d);
           break;
         }
         case NORMAL:
           // Do not occur since the from object has fast properties.
         case HANDLER:
         case INTERCEPTOR:
         case TRANSITION:
         case NONEXISTENT:
           // No element in instance descriptors have proxy or interceptor type.
@@ skipping 159 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   ASSERT(!IsActive());
 }
 
 } }  // namespace v8::internal