Microoptimizations to the way we get the current heap.

src/objects.cc

 // Copyright 2010 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 95 matching lines @@
   return Failure::InternalError();
 }
 
 
 Object* Object::ToBoolean() {
   if (IsTrue()) return this;
   if (IsFalse()) return this;
   if (IsSmi()) {
     return Isolate::Current()->heap()->ToBoolean(Smi::cast(this)->value() != 0);
   }
-  if (IsUndefined() || IsNull()) {
-    return HeapObject::cast(this)->GetHeap()->false_value();
+  HeapObject* heap_this = HeapObject::cast(this);

[Vyacheslav Egorov (Chromium), 2011/03/30 15:57:33]

heap_this is confusing name.

+  if (heap_this->IsUndefined() || heap_this->IsNull()) {
+    return heap_this->GetHeap()->false_value();
   }
   // Undetectable object is false
-  if (IsUndetectableObject()) {
-    return HeapObject::cast(this)->GetHeap()->false_value();
+  if (heap_this->IsUndetectableObject()) {
+    return heap_this->GetHeap()->false_value();
   }
-  if (IsString()) {
-    return HeapObject::cast(this)->GetHeap()->ToBoolean(
+  if (heap_this->IsString()) {
+    return heap_this->GetHeap()->ToBoolean(
         String::cast(this)->length() != 0);
   }
-  if (IsHeapNumber()) {
+  if (heap_this->IsHeapNumber()) {
     return HeapNumber::cast(this)->HeapNumberToBoolean();
   }
-  return Isolate::Current()->heap()->true_value();
+  return heap_this->GetHeap()->true_value();
 }
 
 
 void Object::Lookup(String* name, LookupResult* result) {
-  if (IsJSObject()) return JSObject::cast(this)->Lookup(name, result);
   Object* holder = NULL;
-  if (IsString()) {
-    Heap* heap = HeapObject::cast(this)->GetHeap();
-    Context* global_context = heap->isolate()->context()->global_context();
-    holder = global_context->string_function()->instance_prototype();
-  } else if (IsNumber()) {
+  if (IsSmi()) {
     Heap* heap = Isolate::Current()->heap();
     Context* global_context = heap->isolate()->context()->global_context();
     holder = global_context->number_function()->instance_prototype();
-  } else if (IsBoolean()) {
-    Heap* heap = HeapObject::cast(this)->GetHeap();
-    Context* global_context = heap->isolate()->context()->global_context();
-    holder = global_context->boolean_function()->instance_prototype();
+  } else {
+    HeapObject* heap_this = HeapObject::cast(this);
+    if (heap_this->IsJSObject()) {
+      return JSObject::cast(this)->Lookup(name, result);
+    }
+    Heap* heap = heap_this->GetHeap();
+    if (heap_this->IsString()) {
+      Context* global_context = heap->isolate()->context()->global_context();
+      holder = global_context->string_function()->instance_prototype();
+    } else if (heap_this->IsHeapNumber()) {
+      Context* global_context = heap->isolate()->context()->global_context();
+      holder = global_context->number_function()->instance_prototype();
+    } else if (heap_this->IsBoolean()) {
+      Context* global_context = heap->isolate()->context()->global_context();
+      holder = global_context->boolean_function()->instance_prototype();
+    }
   }
   ASSERT(holder != NULL);  // Cannot handle null or undefined.
   JSObject::cast(holder)->Lookup(name, result);
 }
 
 
 MaybeObject* Object::GetPropertyWithReceiver(Object* receiver,
                                              String* name,
                                              PropertyAttributes* attributes) {
   LookupResult result;
@@ skipping 81 matching lines @@
   return *result;
 }
 
 
 // Only deal with CALLBACKS and INTERCEPTOR
 MaybeObject* JSObject::GetPropertyWithFailedAccessCheck(
     Object* receiver,
     LookupResult* result,
     String* name,
     PropertyAttributes* attributes) {
-  Heap* heap = name->GetHeap();
   if (result->IsProperty()) {
     switch (result->type()) {
       case CALLBACKS: {
         // Only allow API accessors.
         Object* obj = result->GetCallbackObject();
         if (obj->IsAccessorInfo()) {
           AccessorInfo* info = AccessorInfo::cast(obj);
           if (info->all_can_read()) {
             *attributes = result->GetAttributes();
             return GetPropertyWithCallback(receiver,
@@ skipping 31 matching lines @@
         }
         break;
       }
       default:
         UNREACHABLE();
     }
   }
 
   // No accessible property found.
   *attributes = ABSENT;
+  Heap* heap = name->GetHeap();
   heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_GET);
   return heap->undefined_value();
 }
 
 
 PropertyAttributes JSObject::GetPropertyAttributeWithFailedAccessCheck(
     Object* receiver,
     LookupResult* result,
     String* name,
     bool continue_search) {
-  Heap* heap = name->GetHeap();
   if (result->IsProperty()) {
     switch (result->type()) {
       case CALLBACKS: {
         // Only allow API accessors.
         Object* obj = result->GetCallbackObject();
         if (obj->IsAccessorInfo()) {
           AccessorInfo* info = AccessorInfo::cast(obj);
           if (info->all_can_read()) {
             return result->GetAttributes();
           }
@@ skipping 33 matching lines @@
                                                            continue_search);
         }
         break;
       }
 
       default:
         UNREACHABLE();
     }
   }
 
-  heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
+  GetHeap()->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
   return ABSENT;
 }
 
 
 Object* JSObject::GetNormalizedProperty(LookupResult* result) {
   ASSERT(!HasFastProperties());
   Object* value = property_dictionary()->ValueAt(result->GetDictionaryEntry());
   if (IsGlobalObject()) {
     value = JSGlobalPropertyCell::cast(value)->value();
   }
@@ skipping 13 matching lines @@
     property_dictionary()->ValueAtPut(result->GetDictionaryEntry(), value);
   }
   return value;
 }
 
 
 MaybeObject* JSObject::SetNormalizedProperty(String* name,
                                              Object* value,
                                              PropertyDetails details) {
   ASSERT(!HasFastProperties());
-  Heap* heap = name->GetHeap();
   int entry = property_dictionary()->FindEntry(name);
   if (entry == StringDictionary::kNotFound) {
     Object* store_value = value;
     if (IsGlobalObject()) {
+      Heap* heap = name->GetHeap();
       MaybeObject* maybe_store_value =
           heap->AllocateJSGlobalPropertyCell(value);
       if (!maybe_store_value->ToObject(&store_value)) return maybe_store_value;
     }
     Object* dict;
     { MaybeObject* maybe_dict =
           property_dictionary()->Add(name, store_value, details);
       if (!maybe_dict->ToObject(&dict)) return maybe_dict;
     }
     set_properties(StringDictionary::cast(dict));
@@ skipping 11 matching lines @@
     property_dictionary()->DetailsAtPut(entry, details);
   } else {
     property_dictionary()->SetEntry(entry, name, value, details);
   }
   return value;
 }
 
 
 MaybeObject* JSObject::DeleteNormalizedProperty(String* name, DeleteMode mode) {
   ASSERT(!HasFastProperties());
-  Heap* heap = GetHeap();
   StringDictionary* dictionary = property_dictionary();
   int entry = dictionary->FindEntry(name);
   if (entry != StringDictionary::kNotFound) {
     // If we have a global object set the cell to the hole.
     if (IsGlobalObject()) {
       PropertyDetails details = dictionary->DetailsAt(entry);
       if (details.IsDontDelete()) {
-        if (mode != FORCE_DELETION) return heap->false_value();
+        if (mode != FORCE_DELETION) return GetHeap()->false_value();
         // When forced to delete global properties, we have to make a
         // map change to invalidate any ICs that think they can load
         // from the DontDelete cell without checking if it contains
         // the hole value.
         Object* new_map;
         { MaybeObject* maybe_new_map = map()->CopyDropDescriptors();
           if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
         }
         set_map(Map::cast(new_map));
       }
       JSGlobalPropertyCell* cell =
           JSGlobalPropertyCell::cast(dictionary->ValueAt(entry));
-      cell->set_value(heap->the_hole_value());
+      cell->set_value(cell->heap()->the_hole_value());
       dictionary->DetailsAtPut(entry, details.AsDeleted());
     } else {
       return dictionary->DeleteProperty(entry, mode);
     }
   }
-  return heap->true_value();
+  return GetHeap()->true_value();
 }
 
 
 bool JSObject::IsDirty() {
   Object* cons_obj = map()->constructor();
   if (!cons_obj->IsJSFunction())
     return true;
   JSFunction* fun = JSFunction::cast(cons_obj);
   if (!fun->shared()->IsApiFunction())
     return true;
@@ skipping 69 matching lines @@
       return holder->GetPropertyWithInterceptor(recvr, name, attributes);
     }
     default:
       UNREACHABLE();
       return NULL;
   }
 }
 
 
 MaybeObject* Object::GetElementWithReceiver(Object* receiver, uint32_t index) {
-  if (IsJSObject()) {
-    return JSObject::cast(this)->GetElementWithReceiver(receiver, index);
-  }
+  Object* holder = NULL;
+  if (IsSmi()) {
+    Context* global_context = Isolate::Current()->context()->global_context();
+    holder = global_context->number_function()->instance_prototype();
+  } else {
+    HeapObject* heap_this = HeapObject::cast(this);
 
-  Object* holder = NULL;
-  Context* global_context = Isolate::Current()->context()->global_context();
-  if (IsString()) {
-    holder = global_context->string_function()->instance_prototype();
-  } else if (IsNumber()) {
-    holder = global_context->number_function()->instance_prototype();
-  } else if (IsBoolean()) {
-    holder = global_context->boolean_function()->instance_prototype();
-  } else {
-    // Undefined and null have no indexed properties.
-    ASSERT(IsUndefined() || IsNull());
-    return HEAP->undefined_value();
+    if (heap_this->IsJSObject()) {
+      return JSObject::cast(this)->GetElementWithReceiver(receiver, index);
+    }
+    Heap* heap = heap_this->GetHeap();
+    Isolate* isolate = heap->isolate();
+
+    Context* global_context = isolate->context()->global_context();
+    if (heap_this->IsString()) {
+      holder = global_context->string_function()->instance_prototype();
+    } else if (heap_this->IsHeapNumber()) {
+      holder = global_context->number_function()->instance_prototype();
+    } else if (heap_this->IsBoolean()) {
+      holder = global_context->boolean_function()->instance_prototype();
+    } else {
+      // Undefined and null have no indexed properties.
+      ASSERT(heap_this->IsUndefined() || heap_this->IsNull());
+      return heap->undefined_value();
+    }
   }
 
   return JSObject::cast(holder)->GetElementWithReceiver(receiver, index);
 }
 
 
 Object* Object::GetPrototype() {
+  if (IsSmi()) {
+    Heap* heap = Isolate::Current()->heap();
+    Context* context = heap->isolate()->context()->global_context();
+    return context->number_function()->instance_prototype();
+  }
+
+  HeapObject* heap_this = HeapObject::cast(this);
+
   // The object is either a number, a string, a boolean, or a real JS object.
-  if (IsJSObject()) return JSObject::cast(this)->map()->prototype();
-  Heap* heap = Isolate::Current()->heap();
+  if (heap_this->IsJSObject()) return JSObject::cast(this)->map()->prototype();
+  Heap* heap = heap_this->GetHeap();
   Context* context = heap->isolate()->context()->global_context();
 
-  if (IsNumber()) return context->number_function()->instance_prototype();
-  if (IsString()) return context->string_function()->instance_prototype();
-  if (IsBoolean()) {
+  if (heap_this->IsHeapNumber()) {
+    return context->number_function()->instance_prototype();
+  }
+  if (heap_this->IsString()) {
+    return context->string_function()->instance_prototype();
+  }
+  if (heap_this->IsBoolean()) {
     return context->boolean_function()->instance_prototype();
   } else {
     return heap->null_value();
   }
 }
 
 
 void Object::ShortPrint(FILE* out) {
   HeapStringAllocator allocator;
   StringStream accumulator(&allocator);
@@ skipping 307 matching lines @@
         }
       }
       if (!printed) {
         accumulator->Add("<JS Function>");
       }
       break;
     }
     // All other JSObjects are rather similar to each other (JSObject,
     // JSGlobalProxy, JSGlobalObject, JSUndetectableObject, JSValue).
     default: {
-      Heap* heap = GetHeap();
-      Object* constructor = map()->constructor();
+      Map* map_of_this = map();
+      Heap* heap = map_of_this->heap();
+      Object* constructor = map_of_this->constructor();
       bool printed = false;
       if (constructor->IsHeapObject() &&
           !heap->Contains(HeapObject::cast(constructor))) {
         accumulator->Add("!!!INVALID CONSTRUCTOR!!!");
       } else {
         bool global_object = IsJSGlobalProxy();
         if (constructor->IsJSFunction()) {
           if (!heap->Contains(JSFunction::cast(constructor)->shared())) {
             accumulator->Add("!!!INVALID SHARED ON CONSTRUCTOR!!!");
           } else {
@@ skipping 420 matching lines @@
   new_map->set_instance_descriptors(DescriptorArray::cast(new_descriptors));
   set_map(new_map);
   return FastPropertyAtPut(index, value);
 }
 
 
 MaybeObject* JSObject::AddConstantFunctionProperty(
     String* name,
     JSFunction* function,
     PropertyAttributes attributes) {
-  Heap* heap = GetHeap();
-  ASSERT(!heap->InNewSpace(function));
+  ASSERT(!GetHeap()->InNewSpace(function));
 
   // Allocate new instance descriptors with (name, function) added
   ConstantFunctionDescriptor d(name, function, attributes);
   Object* new_descriptors;
   { MaybeObject* maybe_new_descriptors =
         map()->instance_descriptors()->CopyInsert(&d, REMOVE_TRANSITIONS);
     if (!maybe_new_descriptors->ToObject(&new_descriptors)) {
       return maybe_new_descriptors;
     }
   }
 
   // Allocate a new map for the object.
   Object* new_map;
   { MaybeObject* maybe_new_map = map()->CopyDropDescriptors();
     if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
   }
 
   DescriptorArray* descriptors = DescriptorArray::cast(new_descriptors);
   Map::cast(new_map)->set_instance_descriptors(descriptors);
   Map* old_map = map();
   set_map(Map::cast(new_map));
 
   // If the old map is the global object map (from new Object()),
   // then transitions are not added to it, so we are done.
+  Heap* heap = old_map->heap();
   if (old_map == heap->isolate()->context()->global_context()->
       object_function()->map()) {
     return function;
   }
 
   // Do not add CONSTANT_TRANSITIONS to global objects
   if (IsGlobalObject()) {
     return function;
   }
 
@@ skipping 16 matching lines @@
 
   return function;
 }
 
 
 // Add property in slow mode
 MaybeObject* JSObject::AddSlowProperty(String* name,
                                        Object* value,
                                        PropertyAttributes attributes) {
   ASSERT(!HasFastProperties());
-  Heap* heap = GetHeap();
   StringDictionary* dict = property_dictionary();
   Object* store_value = value;
   if (IsGlobalObject()) {
     // In case name is an orphaned property reuse the cell.
     int entry = dict->FindEntry(name);
     if (entry != StringDictionary::kNotFound) {
       store_value = dict->ValueAt(entry);
       JSGlobalPropertyCell::cast(store_value)->set_value(value);
       // Assign an enumeration index to the property and update
       // SetNextEnumerationIndex.
       int index = dict->NextEnumerationIndex();
       PropertyDetails details = PropertyDetails(attributes, NORMAL, index);
       dict->SetNextEnumerationIndex(index + 1);
       dict->SetEntry(entry, name, store_value, details);
       return value;
     }
+    Heap* heap = GetHeap();
     { MaybeObject* maybe_store_value =
           heap->AllocateJSGlobalPropertyCell(value);
       if (!maybe_store_value->ToObject(&store_value)) return maybe_store_value;
     }
     JSGlobalPropertyCell::cast(store_value)->set_value(value);
   }
   PropertyDetails details = PropertyDetails(attributes, NORMAL);
   Object* result;
   { MaybeObject* maybe_result = dict->Add(name, store_value, details);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
   if (dict != result) set_properties(StringDictionary::cast(result));
   return value;
 }
 
 
 MaybeObject* JSObject::AddProperty(String* name,
                                    Object* value,
                                    PropertyAttributes attributes,
                                    StrictModeFlag strict_mode) {
   ASSERT(!IsJSGlobalProxy());
-  Heap* heap = GetHeap();
-  if (!map()->is_extensible()) {
+  Map* map_of_this = map();
+  Heap* heap = map_of_this->heap();
+  if (!map_of_this->is_extensible()) {
     if (strict_mode == kNonStrictMode) {
       return heap->undefined_value();
     } else {
       Handle<Object> args[1] = {Handle<String>(name)};
       return heap->isolate()->Throw(
           *FACTORY->NewTypeError("object_not_extensible",
                                  HandleVector(args, 1)));
     }
   }
   if (HasFastProperties()) {
     // Ensure the descriptor array does not get too big.
-    if (map()->instance_descriptors()->number_of_descriptors() <
+    if (map_of_this->instance_descriptors()->number_of_descriptors() <
         DescriptorArray::kMaxNumberOfDescriptors) {
       if (value->IsJSFunction() && !heap->InNewSpace(value)) {
         return AddConstantFunctionProperty(name,
                                            JSFunction::cast(value),
                                            attributes);
       } else {
         return AddFastProperty(name, value, attributes);
       }
     } else {
       // Normalize the object to prevent very large instance descriptors.
@@ skipping 53 matching lines @@
   { MaybeObject* maybe_result =
         ConvertDescriptorToField(name, new_value, attributes);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
   // If we get to this point we have succeeded - do not return failure
   // after this point.  Later stuff is optional.
   if (!HasFastProperties()) {
     return result;
   }
   // Do not add transitions to the map of "new Object()".
-  if (map() == GetHeap()->isolate()->context()->global_context()->
+  if (map() == old_map->heap()->isolate()->context()->global_context()->
       object_function()->map()) {
     return result;
   }
 
   MapTransitionDescriptor transition(name,
                                      map(),
                                      attributes);
   Object* new_descriptors;
   { MaybeObject* maybe_new_descriptors = old_map->instance_descriptors()->
         CopyInsert(&transition, KEEP_TRANSITIONS);
@@ skipping 278 matching lines @@
   if (number != DescriptorArray::kNotFound) {
     result->DescriptorResult(holder, descriptors->GetDetails(number), number);
   } else {
     result->NotFound();
   }
 }
 
 
 MaybeObject* Map::GetExternalArrayElementsMap(ExternalArrayType array_type,
                                               bool safe_to_add_transition) {
+  Heap* current_heap = heap();
   DescriptorArray* descriptors = instance_descriptors();
-  String* external_array_sentinel_name = GetIsolate()->heap()->empty_symbol();
+  String* external_array_sentinel_name = current_heap->empty_symbol();
 
   if (safe_to_add_transition) {
     // It's only safe to manipulate the descriptor array if it would be
     // safe to add a transition.
 
     ASSERT(!is_shared());  // no transitions can be added to shared maps.
     // Check if the external array transition already exists.
-    DescriptorLookupCache* cache = heap()->isolate()->descriptor_lookup_cache();
+    DescriptorLookupCache* cache =
+        current_heap->isolate()->descriptor_lookup_cache();
     int index = cache->Lookup(descriptors, external_array_sentinel_name);
     if (index == DescriptorLookupCache::kAbsent) {
       index = descriptors->Search(external_array_sentinel_name);
       cache->Update(descriptors,
                     external_array_sentinel_name,
                     index);
     }
 
     // If the transition already exists, check the type. If there is a match,
     // return it.
@@ skipping 113 matching lines @@
   }
   result->NotFound();
 }
 
 
 // We only need to deal with CALLBACKS and INTERCEPTORS
 MaybeObject* JSObject::SetPropertyWithFailedAccessCheck(LookupResult* result,
                                                         String* name,
                                                         Object* value,
                                                         bool check_prototype) {
-  Heap* heap = GetHeap();
   if (check_prototype && !result->IsProperty()) {
     LookupCallbackSetterInPrototypes(name, result);
   }
 
   if (result->IsProperty()) {
     if (!result->IsReadOnly()) {
       switch (result->type()) {
         case CALLBACKS: {
           Object* obj = result->GetCallbackObject();
           if (obj->IsAccessorInfo()) {
@@ skipping 20 matching lines @@
         }
         default: {
           break;
         }
       }
     }
   }
 
   HandleScope scope;
   Handle<Object> value_handle(value);
+  Heap* heap = GetHeap();
   heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_SET);
   return *value_handle;
 }
 
 
 MaybeObject* JSObject::SetProperty(LookupResult* result,
                                    String* name,
                                    Object* value,
                                    PropertyAttributes attributes,
                                    StrictModeFlag strict_mode) {
@@ skipping 117 matching lines @@
 // Set a real local property, even if it is READ_ONLY.  If the property is not
 // present, add it with attributes NONE.  This code is an exact clone of
 // SetProperty, with the check for IsReadOnly and the check for a
 // callback setter removed.  The two lines looking up the LookupResult
 // result are also added.  If one of the functions is changed, the other
 // should be.
 MaybeObject* JSObject::SetLocalPropertyIgnoreAttributes(
     String* name,
     Object* value,
     PropertyAttributes attributes) {
-  Heap* heap = GetHeap();
 
   // Make sure that the top context does not change when doing callbacks or
   // interceptor calls.
   AssertNoContextChange ncc;
   LookupResult result;
   LocalLookup(name, &result);
   // Check access rights if needed.
-  if (IsAccessCheckNeeded()
-      && !heap->isolate()->MayNamedAccess(this, name, v8::ACCESS_SET)) {
-    return SetPropertyWithFailedAccessCheck(&result, name, value, false);
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayNamedAccess(this, name, v8::ACCESS_SET)) {
+      return SetPropertyWithFailedAccessCheck(&result, name, value, false);
+    }
   }
 
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return value;
     ASSERT(proto->IsJSGlobalObject());
     return JSObject::cast(proto)->SetLocalPropertyIgnoreAttributes(
         name,
         value,
         attributes);
@@ skipping 130 matching lines @@
   LookupResult result;
   Lookup(key, &result);
   return GetPropertyAttribute(receiver, &result, key, true);
 }
 
 
 PropertyAttributes JSObject::GetPropertyAttribute(JSObject* receiver,
                                                   LookupResult* result,
                                                   String* name,
                                                   bool continue_search) {
-  Heap* heap = GetHeap();
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayNamedAccess(this, name, v8::ACCESS_HAS)) {
-    return GetPropertyAttributeWithFailedAccessCheck(receiver,
-                                                     result,
-                                                     name,
-                                                     continue_search);
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayNamedAccess(this, name, v8::ACCESS_HAS)) {
+      return GetPropertyAttributeWithFailedAccessCheck(receiver,
+                                                       result,
+                                                       name,
+                                                       continue_search);
+    }
   }
   if (result->IsProperty()) {
     switch (result->type()) {
       case NORMAL:  // fall through
       case FIELD:
       case CONSTANT_FUNCTION:
       case CALLBACKS:
         return result->GetAttributes();
       case INTERCEPTOR:
         return result->holder()->
@@ skipping 119 matching lines @@
 
 MaybeObject* JSObject::NormalizeProperties(PropertyNormalizationMode mode,
                                            int expected_additional_properties) {
   if (!HasFastProperties()) return this;
 
   // The global object is always normalized.
   ASSERT(!IsGlobalObject());
   // JSGlobalProxy must never be normalized
   ASSERT(!IsJSGlobalProxy());
 
-  Heap* heap = GetHeap();
+  Map* map_of_this = map();
 
   // Allocate new content.
-  int property_count = map()->NumberOfDescribedProperties();
+  int property_count = map_of_this->NumberOfDescribedProperties();
   if (expected_additional_properties > 0) {
     property_count += expected_additional_properties;
   } else {
     property_count += 2;  // Make space for two more properties.
   }
   Object* obj;
   { MaybeObject* maybe_obj =
         StringDictionary::Allocate(property_count);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   StringDictionary* dictionary = StringDictionary::cast(obj);
 
-  DescriptorArray* descs = map()->instance_descriptors();
+  DescriptorArray* descs = map_of_this->instance_descriptors();
   for (int i = 0; i < descs->number_of_descriptors(); i++) {
     PropertyDetails details = descs->GetDetails(i);
     switch (details.type()) {
       case CONSTANT_FUNCTION: {
         PropertyDetails d =
             PropertyDetails(details.attributes(), NORMAL, details.index());
         Object* value = descs->GetConstantFunction(i);
         Object* result;
         { MaybeObject* maybe_result =
               dictionary->Add(descs->GetKey(i), value, d);
@@ skipping 29 matching lines @@
       case MAP_TRANSITION:
       case CONSTANT_TRANSITION:
       case NULL_DESCRIPTOR:
       case INTERCEPTOR:
         break;
       default:
         UNREACHABLE();
     }
   }
 
+  Heap* current_heap = map_of_this->heap();
+
   // Copy the next enumeration index from instance descriptor.
-  int index = map()->instance_descriptors()->NextEnumerationIndex();
+  int index = map_of_this->instance_descriptors()->NextEnumerationIndex();
   dictionary->SetNextEnumerationIndex(index);
 
-  { MaybeObject* maybe_obj = heap->isolate()->context()->global_context()->
+  { MaybeObject* maybe_obj =
+        current_heap->isolate()->context()->global_context()->
         normalized_map_cache()->Get(this, mode);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   Map* new_map = Map::cast(obj);
 
   // We have now successfully allocated all the necessary objects.
   // Changes can now be made with the guarantee that all of them take effect.
 
   // Resize the object in the heap if necessary.
   int new_instance_size = new_map->instance_size();
-  int instance_size_delta = map()->instance_size() - new_instance_size;
+  int instance_size_delta = map_of_this->instance_size() - new_instance_size;
   ASSERT(instance_size_delta >= 0);
-  heap->CreateFillerObjectAt(this->address() + new_instance_size,
-                             instance_size_delta);
+  current_heap->CreateFillerObjectAt(this->address() + new_instance_size,
+                                     instance_size_delta);
 
   set_map(new_map);
-  map()->set_instance_descriptors(heap->empty_descriptor_array());
+  new_map->set_instance_descriptors(current_heap->empty_descriptor_array());
 
   set_properties(dictionary);
 
-  heap->isolate()->counters()->props_to_dictionary()->Increment();
+  current_heap->isolate()->counters()->props_to_dictionary()->Increment();
 
 #ifdef DEBUG
   if (FLAG_trace_normalization) {
     PrintF("Object properties have been normalized:\n");
     Print();
   }
 #endif
   return this;
 }
 
 
 MaybeObject* JSObject::TransformToFastProperties(int unused_property_fields) {
   if (HasFastProperties()) return this;
   ASSERT(!IsGlobalObject());
   return property_dictionary()->
       TransformPropertiesToFastFor(this, unused_property_fields);
 }
 
 
 MaybeObject* JSObject::NormalizeElements() {
   ASSERT(!HasExternalArrayElements());
   if (HasDictionaryElements()) return this;
-  ASSERT(map()->has_fast_elements());
+  Map* old_map = map();
+  ASSERT(old_map->has_fast_elements());
 
   Object* obj;
-  { MaybeObject* maybe_obj = map()->GetSlowElementsMap();
+  { MaybeObject* maybe_obj = old_map->GetSlowElementsMap();
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   Map* new_map = Map::cast(obj);
 
   // Get number of entries.
   FixedArray* array = FixedArray::cast(elements());
 
   // Compute the effective length.
   int length = IsJSArray() ?
                Smi::cast(JSArray::cast(this)->length())->value() :
@@ skipping 14 matching lines @@
       }
       dictionary = NumberDictionary::cast(result);
     }
   }
   // Switch to using the dictionary as the backing storage for
   // elements. Set the new map first to satify the elements type
   // assert in set_elements().
   set_map(new_map);
   set_elements(dictionary);
 
-  new_map->GetHeap()->isolate()->counters()->elements_to_dictionary()->
+  new_map->heap()->isolate()->counters()->elements_to_dictionary()->
       Increment();
 
 #ifdef DEBUG
   if (FLAG_trace_normalization) {
     PrintF("Object elements have been normalized:\n");
     Print();
   }
 #endif
 
   return this;
 }
 
 
 MaybeObject* JSObject::DeletePropertyPostInterceptor(String* name,
                                                      DeleteMode mode) {
   // Check local property, ignore interceptor.
-  Heap* heap = GetHeap();
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
-  if (!result.IsProperty()) return heap->true_value();
+  if (!result.IsProperty()) return GetHeap()->true_value();
 
   // Normalize object if needed.
   Object* obj;
   { MaybeObject* maybe_obj = NormalizeProperties(CLEAR_INOBJECT_PROPERTIES, 0);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
 
   return DeleteNormalizedProperty(name, mode);
 }
 
@@ skipping 25 matching lines @@
   }
   MaybeObject* raw_result =
       this_handle->DeletePropertyPostInterceptor(*name_handle, NORMAL_DELETION);
   RETURN_IF_SCHEDULED_EXCEPTION(isolate);
   return raw_result;
 }
 
 
 MaybeObject* JSObject::DeleteElementPostInterceptor(uint32_t index,
                                                     DeleteMode mode) {
-  Heap* heap = GetHeap();
   ASSERT(!HasExternalArrayElements());
   switch (GetElementsKind()) {
     case FAST_ELEMENTS: {
       Object* obj;
       { MaybeObject* maybe_obj = EnsureWritableFastElements();
         if (!maybe_obj->ToObject(&obj)) return maybe_obj;
       }
       uint32_t length = IsJSArray() ?
       static_cast<uint32_t>(Smi::cast(JSArray::cast(this)->length())->value()) :
       static_cast<uint32_t>(FixedArray::cast(elements())->length());
       if (index < length) {
         FixedArray::cast(elements())->set_the_hole(index);
       }
       break;
     }
     case DICTIONARY_ELEMENTS: {
       NumberDictionary* dictionary = element_dictionary();
       int entry = dictionary->FindEntry(index);
       if (entry != NumberDictionary::kNotFound) {
         return dictionary->DeleteProperty(entry, mode);
       }
       break;
     }
     default:
       UNREACHABLE();
       break;
   }
-  return heap->true_value();
+  return GetHeap()->true_value();
 }
 
 
 MaybeObject* JSObject::DeleteElementWithInterceptor(uint32_t index) {
   Isolate* isolate = GetIsolate();
   Heap* heap = isolate->heap();
   // Make sure that the top context does not change when doing
   // callbacks or interceptor calls.
   AssertNoContextChange ncc;
   HandleScope scope(isolate);
@@ skipping 152 matching lines @@
       if (!maybe_obj->ToObject(&obj)) return maybe_obj;
     }
     // Make sure the properties are normalized before removing the entry.
     return DeleteNormalizedProperty(name, mode);
   }
 }
 
 
 // Check whether this object references another object.
 bool JSObject::ReferencesObject(Object* obj) {
-  Heap* heap = GetHeap();
+  Map* map_of_this = map();
+  Heap* heap = map_of_this->heap();
   AssertNoAllocation no_alloc;
 
   // Is the object the constructor for this object?
-  if (map()->constructor() == obj) {
+  if (map_of_this->constructor() == obj) {
     return true;
   }
 
   // Is the object the prototype for this object?
-  if (map()->prototype() == obj) {
+  if (map_of_this->prototype() == obj) {
     return true;
   }
 
   // Check if the object is among the named properties.
   Object* key = SlowReverseLookup(obj);
   if (!key->IsUndefined()) {
     return true;
   }
 
   // Check if the object is among the indexed properties.
@@ skipping 589 matching lines @@
           }
         }
       }
     }
   }
   return heap->undefined_value();
 }
 
 
 Object* JSObject::SlowReverseLookup(Object* value) {
-  Heap* heap = GetHeap();
   if (HasFastProperties()) {
     DescriptorArray* descs = map()->instance_descriptors();
     for (int i = 0; i < descs->number_of_descriptors(); i++) {
       if (descs->GetType(i) == FIELD) {
         if (FastPropertyAt(descs->GetFieldIndex(i)) == value) {
           return descs->GetKey(i);
         }
       } else if (descs->GetType(i) == CONSTANT_FUNCTION) {
         if (descs->GetConstantFunction(i) == value) {
           return descs->GetKey(i);
         }
       }
     }
-    return heap->undefined_value();
+    return GetHeap()->undefined_value();
   } else {
     return property_dictionary()->SlowReverseLookup(value);
   }
 }
 
 
 MaybeObject* Map::CopyDropDescriptors() {
   Heap* heap = GetHeap();
   Object* result;
   { MaybeObject* maybe_result =
@@ skipping 83 matching lines @@
   }
   cast(new_map)->set_instance_descriptors(DescriptorArray::cast(descriptors));
   return new_map;
 }
 
 
 MaybeObject* Map::UpdateCodeCache(String* name, Code* code) {
   // Allocate the code cache if not present.
   if (code_cache()->IsFixedArray()) {
     Object* result;
-    { MaybeObject* maybe_result = GetHeap()->AllocateCodeCache();
+    { MaybeObject* maybe_result = code->heap()->AllocateCodeCache();
       if (!maybe_result->ToObject(&result)) return maybe_result;
     }
     set_code_cache(result);
   }
 
   // Update the code cache.
   return CodeCache::cast(code_cache())->Update(name, code);
 }
 
 
@@ skipping 165 matching lines @@
 Object* CodeCache::Lookup(String* name, Code::Flags flags) {
   if (Code::ExtractTypeFromFlags(flags) == NORMAL) {
     return LookupNormalTypeCache(name, flags);
   } else {
     return LookupDefaultCache(name, flags);
   }
 }
 
 
 Object* CodeCache::LookupDefaultCache(String* name, Code::Flags flags) {
-  Heap* heap = GetHeap();
   FixedArray* cache = default_cache();
   int length = cache->length();
   for (int i = 0; i < length; i += kCodeCacheEntrySize) {
     Object* key = cache->get(i + kCodeCacheEntryNameOffset);
     // Skip deleted elements.
     if (key->IsNull()) continue;
     if (key->IsUndefined()) return key;
     if (name->Equals(String::cast(key))) {
       Code* code = Code::cast(cache->get(i + kCodeCacheEntryCodeOffset));
       if (code->flags() == flags) {
         return code;
       }
     }
   }
-  return heap->undefined_value();
+  return GetHeap()->undefined_value();
 }
 
 
 Object* CodeCache::LookupNormalTypeCache(String* name, Code::Flags flags) {
   if (!normal_type_cache()->IsUndefined()) {
     CodeCacheHashTable* cache = CodeCacheHashTable::cast(normal_type_cache());
     return cache->Lookup(name, flags);
   } else {
     return GetHeap()->undefined_value();
   }
@@ skipping 70 matching lines @@
   uint32_t HashForObject(Object* obj) {
     FixedArray* pair = FixedArray::cast(obj);
     String* name = String::cast(pair->get(0));
     Code* code = Code::cast(pair->get(1));
     return NameFlagsHashHelper(name, code->flags());
   }
 
   MUST_USE_RESULT MaybeObject* AsObject() {
     ASSERT(code_ != NULL);
     Object* obj;
-    { MaybeObject* maybe_obj = code_->GetHeap()->AllocateFixedArray(2);
+    { MaybeObject* maybe_obj = code_->heap()->AllocateFixedArray(2);
       if (!maybe_obj->ToObject(&obj)) return maybe_obj;
     }
     FixedArray* pair = FixedArray::cast(obj);
     pair->set(0, name_);
     pair->set(1, code_);
     return pair;
   }
 
  private:
   String* name_;
@@ skipping 57 matching lines @@
     if (element->IsString() &&
         key->IsString() && String::cast(element)->Equals(String::cast(key))) {
       return true;
     }
   }
   return false;
 }
 
 
 MaybeObject* FixedArray::AddKeysFromJSArray(JSArray* array) {
-  Heap* heap = GetHeap();
   ASSERT(!array->HasExternalArrayElements());
   switch (array->GetElementsKind()) {
     case JSObject::FAST_ELEMENTS:
       return UnionOfKeys(FixedArray::cast(array->elements()));
     case JSObject::DICTIONARY_ELEMENTS: {
       NumberDictionary* dict = array->element_dictionary();
       int size = dict->NumberOfElements();
 
       // Allocate a temporary fixed array.
       Object* object;
-      { MaybeObject* maybe_object = heap->AllocateFixedArray(size);
+      { MaybeObject* maybe_object = GetHeap()->AllocateFixedArray(size);
         if (!maybe_object->ToObject(&object)) return maybe_object;
       }
       FixedArray* key_array = FixedArray::cast(object);
 
       int capacity = dict->Capacity();
       int pos = 0;
       // Copy the elements from the JSArray to the temporary fixed array.
       for (int i = 0; i < capacity; i++) {
         if (dict->IsKey(dict->KeyAt(i))) {
           key_array->set(pos++, dict->ValueAt(i));
         }
       }
       // Compute the union of this and the temporary fixed array.
       return UnionOfKeys(key_array);
     }
     default:
       UNREACHABLE();
   }
   UNREACHABLE();
-  return heap->null_value();  // Failure case needs to "return" a value.
+  return GetHeap()->null_value();  // Failure case needs to "return" a value.
 }
 
 
 MaybeObject* FixedArray::UnionOfKeys(FixedArray* other) {
-  Heap* heap = GetHeap();
   int len0 = length();
 #ifdef DEBUG
   if (FLAG_enable_slow_asserts) {
     for (int i = 0; i < len0; i++) {
       ASSERT(get(i)->IsString() || get(i)->IsNumber());
     }
   }
 #endif
   int len1 = other->length();
   // Optimize if 'other' is empty.
   // We cannot optimize if 'this' is empty, as other may have holes
   // or non keys.
   if (len1 == 0) return this;
 
   // Compute how many elements are not in this.
   int extra = 0;
   for (int y = 0; y < len1; y++) {
     Object* value = other->get(y);
     if (!value->IsTheHole() && !HasKey(this, value)) extra++;
   }
 
   if (extra == 0) return this;
 
   // Allocate the result
   Object* obj;
-  { MaybeObject* maybe_obj = heap->AllocateFixedArray(len0 + extra);
+  { MaybeObject* maybe_obj = GetHeap()->AllocateFixedArray(len0 + extra);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   // Fill in the content
   AssertNoAllocation no_gc;
   FixedArray* result = FixedArray::cast(obj);
   WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
   for (int i = 0; i < len0; i++) {
     Object* e = get(i);
     ASSERT(e->IsString() || e->IsNumber());
     result->set(i, e, mode);
@@ skipping 1299 matching lines @@
     return CompareStringContentsPartial(isolate,
         isolate->objects_string_compare_buffer_a(), rhs);
   }
 }
 
 
 bool String::MarkAsUndetectable() {
   if (StringShape(this).IsSymbol()) return false;
 
   Map* map = this->map();
-  Heap* heap = map->GetHeap();
+  Heap* heap = map->heap();
   if (map == heap->string_map()) {
     this->set_map(heap->undetectable_string_map());
     return true;
   } else if (map == heap->ascii_string_map()) {
     this->set_map(heap->undetectable_ascii_string_map());
     return true;
   }
   // Rest cannot be marked as undetectable
   return false;
 }
@@ skipping 308 matching lines @@
 
 MaybeObject* JSFunction::SetPrototype(Object* value) {
   ASSERT(should_have_prototype());
   Object* construct_prototype = value;
 
   // If the value is not a JSObject, store the value in the map's
   // constructor field so it can be accessed.  Also, set the prototype
   // used for constructing objects to the original object prototype.
   // See ECMA-262 13.2.2.
   if (!value->IsJSObject()) {
-    Heap* heap = GetHeap();
     // Copy the map so this does not affect unrelated functions.
     // Remove map transitions because they point to maps with a
     // different prototype.
-    Object* new_map;
+    Object* new_object;
     { MaybeObject* maybe_new_map = map()->CopyDropTransitions();
-      if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
+      if (!maybe_new_map->ToObject(&new_object)) return maybe_new_map;
     }
-    set_map(Map::cast(new_map));
-    map()->set_constructor(value);
-    map()->set_non_instance_prototype(true);
+    Map* new_map = Map::cast(new_object);
+    Heap* heap = new_map->heap();
+    set_map(new_map);
+    new_map->set_constructor(value);
+    new_map->set_non_instance_prototype(true);
     construct_prototype =
         heap->isolate()->context()->global_context()->
             initial_object_prototype();
   } else {
     map()->set_non_instance_prototype(false);
   }
 
   return SetInstancePrototype(construct_prototype);
 }
 
 
 Object* JSFunction::RemovePrototype() {
   Context* global_context = context()->global_context();
   Map* no_prototype_map = shared()->strict_mode()
       ? global_context->strict_mode_function_without_prototype_map()
       : global_context->function_without_prototype_map();
 
   if (map() == no_prototype_map) {
     // Be idempotent.
     return this;
   }
 
   ASSERT(!shared()->strict_mode() ||
          map() == global_context->strict_mode_function_map());
   ASSERT(shared()->strict_mode() || map() == global_context->function_map());
 
   set_map(no_prototype_map);
-  set_prototype_or_initial_map(GetHeap()->the_hole_value());
+  set_prototype_or_initial_map(no_prototype_map->heap()->the_hole_value());
   return this;
 }
 
 
 Object* JSFunction::SetInstanceClassName(String* name) {
   shared()->set_instance_class_name(name);
   return this;
 }
 
 
@@ skipping 61 matching lines @@
   return instance_size;
 }
 
 
 int SharedFunctionInfo::CalculateInObjectProperties() {
   return (CalculateInstanceSize() - JSObject::kHeaderSize) / kPointerSize;
 }
 
 
 bool SharedFunctionInfo::CanGenerateInlineConstructor(Object* prototype) {
-  Heap* heap = GetHeap();
-
   // Check the basic conditions for generating inline constructor code.
   if (!FLAG_inline_new
       || !has_only_simple_this_property_assignments()
       || this_property_assignments_count() == 0) {
     return false;
   }
 
   // If the prototype is null inline constructors cause no problems.
   if (!prototype->IsJSObject()) {
     ASSERT(prototype->IsNull());
     return true;
   }
 
+  Heap* heap = GetHeap();
+
   // Traverse the proposed prototype chain looking for setters for properties of
   // the same names as are set by the inline constructor.
   for (Object* obj = prototype;
        obj != heap->null_value();
        obj = obj->GetPrototype()) {
     JSObject* js_object = JSObject::cast(obj);
     for (int i = 0; i < this_property_assignments_count(); i++) {
       LookupResult result;
       String* name = GetThisPropertyAssignmentName(i);
       js_object->LocalLookupRealNamedProperty(name, &result);
@@ skipping 299 matching lines @@
          (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
           rinfo->IsPatchedDebugBreakSlotSequence()));
   Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address());
   Object* old_target = target;
   VisitPointer(&target);
   CHECK_EQ(target, old_target);  // VisitPointer doesn't change Code* *target.
 }
 
 
 void Code::InvalidateRelocation() {
-  set_relocation_info(GetHeap()->empty_byte_array());
+  set_relocation_info(heap()->empty_byte_array());
 }
 
 
 void Code::Relocate(intptr_t delta) {
   for (RelocIterator it(this, RelocInfo::kApplyMask); !it.done(); it.next()) {
     it.rinfo()->apply(delta);
   }
   CPU::FlushICache(instruction_start(), instruction_size());
 }
 
@@ skipping 557 matching lines @@
 
 static Failure* ArrayLengthRangeError(Heap* heap) {
   HandleScope scope;
   return heap->isolate()->Throw(
       *FACTORY->NewRangeError("invalid_array_length",
           HandleVector<Object>(NULL, 0)));
 }
 
 
 MaybeObject* JSObject::SetElementsLength(Object* len) {
-  Heap* heap = GetHeap();
   // We should never end in here with a pixel or external array.
   ASSERT(AllowsSetElementsLength());
 
   MaybeObject* maybe_smi_length = len->ToSmi();
   Object* smi_length = Smi::FromInt(0);
   if (maybe_smi_length->ToObject(&smi_length) && smi_length->IsSmi()) {
     const int value = Smi::cast(smi_length)->value();
-    if (value < 0) return ArrayLengthRangeError(heap);
+    if (value < 0) return ArrayLengthRangeError(GetHeap());
     switch (GetElementsKind()) {
       case FAST_ELEMENTS: {
         int old_capacity = FixedArray::cast(elements())->length();
         if (value <= old_capacity) {
           if (IsJSArray()) {
             Object* obj;
             { MaybeObject* maybe_obj = EnsureWritableFastElements();
               if (!maybe_obj->ToObject(&obj)) return maybe_obj;
             }
             int old_length = FastD2I(JSArray::cast(this)->length()->Number());
@@ skipping 45 matching lines @@
         break;
     }
   }
 
   // General slow case.
   if (len->IsNumber()) {
     uint32_t length;
     if (len->ToArrayIndex(&length)) {
       return SetSlowElements(len);
     } else {
-      return ArrayLengthRangeError(heap);
+      return ArrayLengthRangeError(GetHeap());
     }
   }
 
   // len is not a number so make the array size one and
   // set only element to len.
   Object* obj;
-  { MaybeObject* maybe_obj = heap->AllocateFixedArray(1);
+  { MaybeObject* maybe_obj = GetHeap()->AllocateFixedArray(1);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   FixedArray::cast(obj)->set(0, len);
   if (IsJSArray()) JSArray::cast(this)->set_length(Smi::FromInt(1));
   set_elements(FixedArray::cast(obj));
   return this;
 }
 
 
 MaybeObject* JSObject::SetPrototype(Object* value,
@@ skipping 134 matching lines @@
       VMState state(isolate, EXTERNAL);
       result = getter(index, info);
     }
     if (!result.IsEmpty()) return true;
   }
   return holder_handle->HasElementPostInterceptor(*receiver_handle, index);
 }
 
 
 JSObject::LocalElementType JSObject::HasLocalElement(uint32_t index) {
-  Heap* heap = GetHeap();
 
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_HAS)) {
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
-    return UNDEFINED_ELEMENT;
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_HAS)) {
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
+      return UNDEFINED_ELEMENT;
+    }
   }
 
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return UNDEFINED_ELEMENT;
     ASSERT(proto->IsJSGlobalObject());
     return JSObject::cast(proto)->HasLocalElement(index);
   }
 
   // Check for lookup interceptor
@@ skipping 45 matching lines @@
     default:
       UNREACHABLE();
       break;
   }
 
   return UNDEFINED_ELEMENT;
 }
 
 
 bool JSObject::HasElementWithReceiver(JSObject* receiver, uint32_t index) {
-  Heap* heap = GetHeap();
-
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_HAS)) {
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
-    return false;
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_HAS)) {
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
+      return false;
+    }
   }
 
   // Check for lookup interceptor
   if (HasIndexedInterceptor()) {
     return HasElementWithInterceptor(receiver, index);
   }
 
   switch (GetElementsKind()) {
     case FAST_ELEMENTS: {
       uint32_t length = IsJSArray() ?
@@ skipping 251 matching lines @@
   }
   ASSERT(HasDictionaryElements());
   return SetElement(index, value, strict_mode, check_prototype);
 }
 
 
 MaybeObject* JSObject::SetElement(uint32_t index,
                                   Object* value,
                                   StrictModeFlag strict_mode,
                                   bool check_prototype) {
-  Heap* heap = GetHeap();
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_SET)) {
-    HandleScope scope;
-    Handle<Object> value_handle(value);
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_SET);
-    return *value_handle;
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_SET)) {
+      HandleScope scope;
+      Handle<Object> value_handle(value);
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_SET);
+      return *value_handle;
+    }
   }
 
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return value;
     ASSERT(proto->IsJSGlobalObject());
     return JSObject::cast(proto)->SetElement(index,
                                              value,
                                              strict_mode,
                                              check_prototype);
@@ skipping 174 matching lines @@
       if (!maybe_len->ToObject(&len)) return maybe_len;
     }
     set_length(len);
   }
   return value;
 }
 
 
 MaybeObject* JSObject::GetElementPostInterceptor(Object* receiver,
                                                  uint32_t index) {
-  Heap* heap = GetHeap();
   // Get element works for both JSObject and JSArray since
   // JSArray::length cannot change.
   switch (GetElementsKind()) {
     case FAST_ELEMENTS: {
       FixedArray* elms = FixedArray::cast(elements());
       if (index < static_cast<uint32_t>(elms->length())) {
         Object* value = elms->get(index);
         if (!value->IsTheHole()) return value;
       }
       break;
@@ skipping 28 matching lines @@
       }
       break;
     }
     default:
       UNREACHABLE();
       break;
   }
 
   // Continue searching via the prototype chain.
   Object* pt = GetPrototype();
-  if (pt->IsNull()) return heap->undefined_value();
+  if (pt->IsNull()) return GetHeap()->undefined_value();
   return pt->GetElementWithReceiver(receiver, index);
 }
 
 
 MaybeObject* JSObject::GetElementWithInterceptor(Object* receiver,
                                                  uint32_t index) {
   Isolate* isolate = GetIsolate();
   // Make sure that the top context does not change when doing
   // callbacks or interceptor calls.
   AssertNoContextChange ncc;
@@ skipping 21 matching lines @@
 
   MaybeObject* raw_result =
       holder_handle->GetElementPostInterceptor(*this_handle, index);
   RETURN_IF_SCHEDULED_EXCEPTION(isolate);
   return raw_result;
 }
 
 
 MaybeObject* JSObject::GetElementWithReceiver(Object* receiver,
                                               uint32_t index) {
-  Heap* heap = GetHeap();
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_GET)) {
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_GET);
-    return heap->undefined_value();
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_GET)) {
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_GET);
+      return heap->undefined_value();
+    }
   }
 
   if (HasIndexedInterceptor()) {
     return GetElementWithInterceptor(receiver, index);
   }
 
   // Get element works for both JSObject and JSArray since
   // JSArray::length cannot change.
   switch (GetElementsKind()) {
     case FAST_ELEMENTS: {
@@ skipping 30 matching lines @@
                                         index,
                                         this);
         }
         return element;
       }
       break;
     }
   }
 
   Object* pt = GetPrototype();
+  Heap* heap = GetHeap();
   if (pt == heap->null_value()) return heap->undefined_value();
   return pt->GetElementWithReceiver(receiver, index);
 }
 
 
 MaybeObject* JSObject::GetExternalElement(uint32_t index) {
   // Get element works for both JSObject and JSArray since
   // JSArray::length cannot change.
   switch (GetElementsKind()) {
     case EXTERNAL_PIXEL_ELEMENTS: {
@@ skipping 206 matching lines @@
   Object* result =
       constructor->shared()->get_api_func_data()->indexed_property_handler();
   return InterceptorInfo::cast(result);
 }
 
 
 MaybeObject* JSObject::GetPropertyPostInterceptor(
     JSObject* receiver,
     String* name,
     PropertyAttributes* attributes) {
-  Heap* heap = GetHeap();
   // Check local property in holder, ignore interceptor.
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
   if (result.IsProperty()) {
     return GetProperty(receiver, &result, name, attributes);
   }
   // Continue searching via the prototype chain.
   Object* pt = GetPrototype();
   *attributes = ABSENT;
-  if (pt->IsNull()) return heap->undefined_value();
+  if (pt->IsNull()) return GetHeap()->undefined_value();
   return pt->GetPropertyWithReceiver(receiver, name, attributes);
 }
 
 
 MaybeObject* JSObject::GetLocalPropertyPostInterceptor(
     JSObject* receiver,
     String* name,
     PropertyAttributes* attributes) {
-  Heap* heap = GetHeap();
   // Check local property in holder, ignore interceptor.
   LookupResult result;
   LocalLookupRealNamedProperty(name, &result);
   if (result.IsProperty()) {
     return GetProperty(receiver, &result, name, attributes);
   }
-  return heap->undefined_value();
+  return GetHeap()->undefined_value();
 }
 
 
 MaybeObject* JSObject::GetPropertyWithInterceptor(
     JSObject* receiver,
     String* name,
     PropertyAttributes* attributes) {
   Isolate* isolate = GetIsolate();
   InterceptorInfo* interceptor = GetNamedInterceptor();
   HandleScope scope(isolate);
@@ skipping 24 matching lines @@
   MaybeObject* result = holder_handle->GetPropertyPostInterceptor(
       *receiver_handle,
       *name_handle,
       attributes);
   RETURN_IF_SCHEDULED_EXCEPTION(isolate);
   return result;
 }
 
 
 bool JSObject::HasRealNamedProperty(String* key) {
-  Heap* heap = GetHeap();
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayNamedAccess(this, key, v8::ACCESS_HAS)) {
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
-    return false;
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayNamedAccess(this, key, v8::ACCESS_HAS)) {
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
+      return false;
+    }
   }
 
   LookupResult result;
   LocalLookupRealNamedProperty(key, &result);
   return result.IsProperty() && (result.type() != INTERCEPTOR);
 }
 
 
 bool JSObject::HasRealElementProperty(uint32_t index) {
-  Heap* heap = GetHeap();
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_HAS)) {
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
-    return false;
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayIndexedAccess(this, index, v8::ACCESS_HAS)) {
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
+      return false;
+    }
   }
 
   // Handle [] on String objects.
   if (this->IsStringObjectWithCharacterAt(index)) return true;
 
   switch (GetElementsKind()) {
     case FAST_ELEMENTS: {
       uint32_t length = IsJSArray() ?
           static_cast<uint32_t>(
               Smi::cast(JSArray::cast(this)->length())->value()) :
@@ skipping 18 matching lines @@
     case DICTIONARY_ELEMENTS: {
       return element_dictionary()->FindEntry(index)
           != NumberDictionary::kNotFound;
     }
     default:
       UNREACHABLE();
       break;
   }
   // All possibilities have been handled above already.
   UNREACHABLE();
-  return heap->null_value();
+  return GetHeap()->null_value();
 }
 
 
 bool JSObject::HasRealNamedCallbackProperty(String* key) {
-  Heap* heap = GetHeap();
   // Check access rights if needed.
-  if (IsAccessCheckNeeded() &&
-      !heap->isolate()->MayNamedAccess(this, key, v8::ACCESS_HAS)) {
-    heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
-    return false;
+  if (IsAccessCheckNeeded()) {
+    Heap* heap = GetHeap();
+    if (!heap->isolate()->MayNamedAccess(this, key, v8::ACCESS_HAS)) {
+      heap->isolate()->ReportFailedAccessCheck(this, v8::ACCESS_HAS);
+      return false;
+    }
   }
 
   LookupResult result;
   LocalLookupRealNamedProperty(key, &result);
   return result.IsProperty() && (result.type() == CALLBACKS);
 }
 
 
 int JSObject::NumberOfLocalProperties(PropertyAttributes filter) {
   if (HasFastProperties()) {
@@ skipping 618 matching lines @@
     }
     ASSERT(element->IsNull() || !String::cast(element)->Equals(key));
     entry = NextProbe(entry, count++, capacity);
   }
   return kNotFound;
 }
 
 
 template<typename Shape, typename Key>
 MaybeObject* HashTable<Shape, Key>::EnsureCapacity(int n, Key key) {
-  Heap* heap = GetHeap();
   int capacity = Capacity();
   int nof = NumberOfElements() + n;
   int nod = NumberOfDeletedElements();
   // Return if:
   //   50% is still free after adding n elements and
   //   at most 50% of the free elements are deleted elements.
   if (nod <= (capacity - nof) >> 1) {
     int needed_free = nof >> 1;
     if (nof + needed_free <= capacity) return this;
   }
 
   const int kMinCapacityForPretenure = 256;
   bool pretenure =
-      (capacity > kMinCapacityForPretenure) && !heap->InNewSpace(this);
+      (capacity > kMinCapacityForPretenure) && !GetHeap()->InNewSpace(this);
   Object* obj;
   { MaybeObject* maybe_obj =
         Allocate(nof * 2, pretenure ? TENURED : NOT_TENURED);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
 
   AssertNoAllocation no_gc;
   HashTable* table = HashTable::cast(obj);
   WriteBarrierMode mode = table->GetWriteBarrierMode(no_gc);
 
@@ skipping 111 matching lines @@
 template
 int Dictionary<StringDictionaryShape, String*>::NumberOfEnumElements();
 
 template
 int HashTable<NumberDictionaryShape, uint32_t>::FindEntry(uint32_t);
 
 
 // Collates undefined and unexisting elements below limit from position
 // zero of the elements. The object stays in Dictionary mode.
 MaybeObject* JSObject::PrepareSlowElementsForSort(uint32_t limit) {
-  Heap* heap = GetHeap();
   ASSERT(HasDictionaryElements());
   // Must stay in dictionary mode, either because of requires_slow_elements,
   // or because we are not going to sort (and therefore compact) all of the
   // elements.
   NumberDictionary* dict = element_dictionary();
   HeapNumber* result_double = NULL;
   if (limit > static_cast<uint32_t>(Smi::kMaxValue)) {
     // Allocate space for result before we start mutating the object.
     Object* new_double;
-    { MaybeObject* maybe_new_double = heap->AllocateHeapNumber(0.0);
+    { MaybeObject* maybe_new_double = GetHeap()->AllocateHeapNumber(0.0);
       if (!maybe_new_double->ToObject(&new_double)) return maybe_new_double;
     }
     result_double = HeapNumber::cast(new_double);
   }
 
   Object* obj;
   { MaybeObject* maybe_obj =
         NumberDictionary::Allocate(dict->NumberOfElements());
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
@@ skipping 39 matching lines @@
           // allocation. Bailout.
           return Smi::FromInt(-1);
         }
         new_dict->AddNumberEntry(key, value, details)->ToObjectUnchecked();
       }
     }
   }
 
   uint32_t result = pos;
   PropertyDetails no_details = PropertyDetails(NONE, NORMAL);
+  Heap* heap = GetHeap();
   while (undefs > 0) {
     if (pos > static_cast<uint32_t>(Smi::kMaxValue)) {
       // Adding an entry with the key beyond smi-range requires
       // allocation. Bailout.
       return Smi::FromInt(-1);
     }
     new_dict->AddNumberEntry(pos, heap->undefined_value(), no_details)->
         ToObjectUnchecked();
     pos++;
     undefs--;
   }
 
   set_elements(new_dict);
 
   if (result <= static_cast<uint32_t>(Smi::kMaxValue)) {
     return Smi::FromInt(static_cast<int>(result));
   }
 
   ASSERT_NE(NULL, result_double);
   result_double->set_value(static_cast<double>(result));
   return result_double;
 }
 
 
 // Collects all defined (non-hole) and non-undefined (array) elements at
 // the start of the elements array.
 // If the object is in dictionary mode, it is converted to fast elements
 // mode.
 MaybeObject* JSObject::PrepareElementsForSort(uint32_t limit) {
+  ASSERT(!HasExternalArrayElements());
+
   Heap* heap = GetHeap();
-  ASSERT(!HasExternalArrayElements());
 
   if (HasDictionaryElements()) {
     // Convert to fast elements containing only the existing properties.
     // Ordering is irrelevant, since we are going to sort anyway.
     NumberDictionary* dict = element_dictionary();
     if (IsJSArray() || dict->requires_slow_elements() ||
         dict->max_number_key() >= limit) {
       return PrepareSlowElementsForSort(limit);
     }
     // Convert to fast elements.
@@ skipping 234 matching lines @@
 
 JSGlobalPropertyCell* GlobalObject::GetPropertyCell(LookupResult* result) {
   ASSERT(!HasFastProperties());
   Object* value = property_dictionary()->ValueAt(result->GetDictionaryEntry());
   return JSGlobalPropertyCell::cast(value);
 }
 
 
 MaybeObject* GlobalObject::EnsurePropertyCell(String* name) {
   ASSERT(!HasFastProperties());
-  Heap* heap = GetHeap();
   int entry = property_dictionary()->FindEntry(name);
   if (entry == StringDictionary::kNotFound) {
+    Heap* heap = GetHeap();
     Object* cell;
     { MaybeObject* maybe_cell =
           heap->AllocateJSGlobalPropertyCell(heap->the_hole_value());
       if (!maybe_cell->ToObject(&cell)) return maybe_cell;
     }
     PropertyDetails details(NONE, NORMAL);
     details = details.AsDeleted();
     Object* dictionary;
     { MaybeObject* maybe_dictionary =
           property_dictionary()->Add(name, cell, details);
@@ skipping 154 matching lines @@
   // Add the new symbol and return it along with the symbol table.
   entry = table->FindInsertionEntry(key->Hash());
   table->set(EntryToIndex(entry), symbol);
   table->ElementAdded();
   *s = symbol;
   return table;
 }
 
 
 Object* CompilationCacheTable::Lookup(String* src) {
-  Heap* heap = GetHeap();
   StringKey key(src);
   int entry = FindEntry(&key);
-  if (entry == kNotFound) return heap->undefined_value();
+  if (entry == kNotFound) return GetHeap()->undefined_value();
   return get(EntryToIndex(entry) + 1);
 }
 
 
 Object* CompilationCacheTable::LookupEval(String* src,
                                           Context* context,
                                           StrictModeFlag strict_mode) {
   StringSharedKey key(src, context->closure()->shared(), strict_mode);
   int entry = FindEntry(&key);
   if (entry == kNotFound) return GetHeap()->undefined_value();
   return get(EntryToIndex(entry) + 1);
 }
 
 
 Object* CompilationCacheTable::LookupRegExp(String* src,
                                             JSRegExp::Flags flags) {
-  Heap* heap = GetHeap();
   RegExpKey key(src, flags);
   int entry = FindEntry(&key);
-  if (entry == kNotFound) return heap->undefined_value();
+  if (entry == kNotFound) return GetHeap()->undefined_value();
   return get(EntryToIndex(entry) + 1);
 }
 
 
 MaybeObject* CompilationCacheTable::Put(String* src, Object* value) {
   StringKey key(src);
   Object* obj;
   { MaybeObject* maybe_obj = EnsureCapacity(1, &key);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
@@ skipping 99 matching lines @@
   }
 
   Object* AsObject() { return symbols_; }
 
  private:
   FixedArray* symbols_;
 };
 
 
 Object* MapCache::Lookup(FixedArray* array) {
-  Heap* heap = GetHeap();
   SymbolsKey key(array);
   int entry = FindEntry(&key);
-  if (entry == kNotFound) return heap->undefined_value();
+  if (entry == kNotFound) return GetHeap()->undefined_value();
   return get(EntryToIndex(entry) + 1);
 }
 
 
 MaybeObject* MapCache::Put(FixedArray* array, Map* value) {
   SymbolsKey key(array);
   Object* obj;
   { MaybeObject* maybe_obj = EnsureCapacity(1, &key);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
@@ skipping 335 matching lines @@
       storage->set(index++, k);
     }
   }
   ASSERT(storage->length() >= index);
 }
 
 
 // Backwards lookup (slow).
 template<typename Shape, typename Key>
 Object* Dictionary<Shape, Key>::SlowReverseLookup(Object* value) {
-  Heap* heap = Dictionary<Shape, Key>::GetHeap();
   int capacity = HashTable<Shape, Key>::Capacity();
   for (int i = 0; i < capacity; i++) {
     Object* k =  HashTable<Shape, Key>::KeyAt(i);
     if (Dictionary<Shape, Key>::IsKey(k)) {
       Object* e = ValueAt(i);
       if (e->IsJSGlobalPropertyCell()) {
         e = JSGlobalPropertyCell::cast(e)->value();
       }
       if (e == value) return k;
     }
   }
+  Heap* heap = Dictionary<Shape, Key>::GetHeap();
   return heap->undefined_value();
 }
 
 
 MaybeObject* StringDictionary::TransformPropertiesToFastFor(
     JSObject* obj, int unused_property_fields) {
-  Heap* heap = GetHeap();
   // Make sure we preserve dictionary representation if there are too many
   // descriptors.
   if (NumberOfElements() > DescriptorArray::kMaxNumberOfDescriptors) return obj;
 
   // Figure out if it is necessary to generate new enumeration indices.
   int max_enumeration_index =
       NextEnumerationIndex() +
           (DescriptorArray::kMaxNumberOfDescriptors -
            NumberOfElements());
   if (!PropertyDetails::IsValidIndex(max_enumeration_index)) {
     Object* result;
     { MaybeObject* maybe_result = GenerateNewEnumerationIndices();
       if (!maybe_result->ToObject(&result)) return maybe_result;
     }
   }
 
   int instance_descriptor_length = 0;
   int number_of_fields = 0;
 
+  Heap* heap = GetHeap();
+
   // Compute the length of the instance descriptor.
   int capacity = Capacity();
   for (int i = 0; i < capacity; i++) {
     Object* k = KeyAt(i);
     if (IsKey(k)) {
       Object* value = ValueAt(i);
       PropertyType type = DetailsAt(i).type();
       ASSERT(type != FIELD);
       instance_descriptor_length++;
       if (type == NORMAL &&
@@ skipping 108 matching lines @@
 
   // If there is no break point info object or no break points in the break
   // point info object there is no break point at this code position.
   if (break_point_info->IsUndefined()) return false;
   return BreakPointInfo::cast(break_point_info)->GetBreakPointCount() > 0;
 }
 
 
 // Get the break point info object for this code position.
 Object* DebugInfo::GetBreakPointInfo(int code_position) {
-  Heap* heap = GetHeap();
   // Find the index of the break point info object for this code position.
   int index = GetBreakPointInfoIndex(code_position);
 
   // Return the break point info object if any.
-  if (index == kNoBreakPointInfo) return heap->undefined_value();
+  if (index == kNoBreakPointInfo) return GetHeap()->undefined_value();
   return BreakPointInfo::cast(break_points()->get(index));
 }
 
 
 // Clear a break point at the specified code position.
 void DebugInfo::ClearBreakPoint(Handle<DebugInfo> debug_info,
                                 int code_position,
                                 Handle<Object> break_point_object) {
   Handle<Object> break_point_info(debug_info->GetBreakPointInfo(code_position));
   if (break_point_info->IsUndefined()) return;
@@ skipping 52 matching lines @@
       set_statement_position(Smi::FromInt(statement_position));
   new_break_point_info->set_break_point_objects(
       isolate->heap()->undefined_value());
   BreakPointInfo::SetBreakPoint(new_break_point_info, break_point_object);
   debug_info->break_points()->set(index, *new_break_point_info);
 }
 
 
 // Get the break point objects for a code position.
 Object* DebugInfo::GetBreakPointObjects(int code_position) {
-  Heap* heap = GetHeap();
   Object* break_point_info = GetBreakPointInfo(code_position);
   if (break_point_info->IsUndefined()) {
-    return heap->undefined_value();
+    return GetHeap()->undefined_value();
   }
   return BreakPointInfo::cast(break_point_info)->break_point_objects();
 }
 
 
 // Get the total number of break points.
 int DebugInfo::GetBreakPointCount() {
   if (break_points()->IsUndefined()) return 0;
   int count = 0;
   for (int i = 0; i < break_points()->length(); i++) {
     if (!break_points()->get(i)->IsUndefined()) {
       BreakPointInfo* break_point_info =
           BreakPointInfo::cast(break_points()->get(i));
       count += break_point_info->GetBreakPointCount();
     }
   }
   return count;
 }
 
 
 Object* DebugInfo::FindBreakPointInfo(Handle<DebugInfo> debug_info,
                                       Handle<Object> break_point_object) {
-  Heap* heap = Isolate::Current()->heap();
+  Heap* heap = debug_info->GetHeap();
   if (debug_info->break_points()->IsUndefined()) return heap->undefined_value();
   for (int i = 0; i < debug_info->break_points()->length(); i++) {
     if (!debug_info->break_points()->get(i)->IsUndefined()) {
       Handle<BreakPointInfo> break_point_info =
           Handle<BreakPointInfo>(BreakPointInfo::cast(
               debug_info->break_points()->get(i)));
       if (BreakPointInfo::HasBreakPointObject(break_point_info,
                                               break_point_object)) {
         return *break_point_info;
       }
@@ skipping 116 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal