This is a little experiment to move Failure to a superclass above Object...

src/objects-inl.h

 // Copyright 2006-2008 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 1186 matching lines @@
 }
 
 
 void JSObject::initialize_elements() {
   ASSERT(map()->has_fast_elements());
   ASSERT(!Heap::InNewSpace(Heap::empty_fixed_array()));
   WRITE_FIELD(this, kElementsOffset, Heap::empty_fixed_array());
 }
 
 
+  Object* obj;
+  { TryAllocation t = map()->GetFastElementsMap();
+    if (!t->ToObject(&obj)) return t;
+  }
 Object* JSObject::ResetElements() {
-  Object* obj = map()->GetFastElementsMap();
-  if (obj->IsFailure()) return obj;
   set_map(Map::cast(obj));
   initialize_elements();
   return this;
 }
 
 
 ACCESSORS(Oddball, to_string, String, kToStringOffset)
 ACCESSORS(Oddball, to_number, Object, kToNumberOffset)
 
 
@@ skipping 1255 matching lines @@
 
 
 void Map::set_prototype(Object* value, WriteBarrierMode mode) {
   ASSERT(value->IsNull() || value->IsJSObject());
   WRITE_FIELD(this, kPrototypeOffset, value);
   CONDITIONAL_WRITE_BARRIER(this, kPrototypeOffset, mode);
 }
 
 
 Object* Map::GetFastElementsMap() {
+  Object* obj;
+  { TryAllocation t = CopyDropTransitions();
+    if (!t->ToObject(&obj)) return t;
+  }
   if (has_fast_elements()) return this;
-  Object* obj = CopyDropTransitions();
-  if (obj->IsFailure()) return obj;
   Map* new_map = Map::cast(obj);
   new_map->set_has_fast_elements(true);
   Counters::map_slow_to_fast_elements.Increment();
   return new_map;
 }
 
 
 Object* Map::GetSlowElementsMap() {
+  Object* obj;
+  { TryAllocation t = CopyDropTransitions();
+    if (!t->ToObject(&obj)) return t;
+  }
   if (!has_fast_elements()) return this;
-  Object* obj = CopyDropTransitions();
-  if (obj->IsFailure()) return obj;
   Map* new_map = Map::cast(obj);
   new_map->set_has_fast_elements(false);
   Counters::map_fast_to_slow_elements.Increment();
   return new_map;
 }
 
 
 ACCESSORS(Map, instance_descriptors, DescriptorArray,
           kInstanceDescriptorsOffset)
 ACCESSORS(Map, code_cache, Object, kCodeCacheOffset)
@@ skipping 683 matching lines @@
   bool result = elements()->IsFixedArray();
   ASSERT(result == (!HasPixelElements() && !HasExternalArrayElements()));
   return result;
 }
 
 
 Object* JSObject::EnsureWritableFastElements() {
   ASSERT(HasFastElements());
   FixedArray* elems = FixedArray::cast(elements());
   if (elems->map() != Heap::fixed_cow_array_map()) return elems;
-  Object* writable_elems = Heap::CopyFixedArrayWithMap(elems,
-                                                       Heap::fixed_array_map());
-  if (writable_elems->IsFailure()) return writable_elems;
+  Object* writable_elems;
+  { TryAllocation t = Heap::CopyFixedArrayWithMap(elems,
+                                                         Heap::fixed_array_map());
+    if (!t->ToObject(&writable_elems)) return t;
+  }
   set_elements(FixedArray::cast(writable_elems));
   Counters::cow_arrays_converted.Increment();
   return writable_elems;
 }
 
 
 StringDictionary* JSObject::property_dictionary() {
   ASSERT(!HasFastProperties());
   return StringDictionary::cast(properties());
 }
@@ skipping 335 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_