Fix CurrentMapForDeprecated() to return MaybeHandle instead of a null handle.

src/objects.cc

 // Copyright 2013 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 2748 matching lines @@
     if (descriptors->GetDetails(i).type() == FIELD) {
       map = GeneralizeRepresentation(map, i, Representation::Tagged(),
                                      HeapType::Any(map->GetIsolate()),
                                      FORCE_FIELD);
     }
   }
   return map;
 }
 
 
-Handle<Map> Map::CurrentMapForDeprecated(Handle<Map> map) {
+// static
+MaybeHandle<Map> Map::CurrentMapForDeprecated(Handle<Map> map) {
   Handle<Map> proto_map(map);
   while (proto_map->prototype()->IsJSObject()) {
     Handle<JSObject> holder(JSObject::cast(proto_map->prototype()));
-    if (holder->map()->is_deprecated()) {
-      JSObject::TryMigrateInstance(holder);
+    proto_map = Handle<Map>(holder->map());
+    if (proto_map->is_deprecated() && JSObject::TryMigrateInstance(holder)) {
+      proto_map = Handle<Map>(holder->map());
     }
-    proto_map = Handle<Map>(holder->map());
   }
   return CurrentMapForDeprecatedInternal(map);
 }
 
 
-Handle<Map> Map::CurrentMapForDeprecatedInternal(Handle<Map> map) {
+// static
+MaybeHandle<Map> Map::CurrentMapForDeprecatedInternal(Handle<Map> map) {
   if (!map->is_deprecated()) return map;
 
   DisallowHeapAllocation no_allocation;
   DescriptorArray* old_descriptors = map->instance_descriptors();
 
   int descriptors = map->NumberOfOwnDescriptors();
   Map* root_map = map->FindRootMap();
 
   // Check the state of the root map.
-  if (!map->EquivalentToForTransition(root_map)) return Handle<Map>();
+  if (!map->EquivalentToForTransition(root_map)) return MaybeHandle<Map>();
   int verbatim = root_map->NumberOfOwnDescriptors();
 
   Map* updated = root_map->FindUpdatedMap(
       verbatim, descriptors, old_descriptors);
-  if (updated == NULL) return Handle<Map>();
+  if (updated == NULL) return MaybeHandle<Map>();
 
   DescriptorArray* updated_descriptors = updated->instance_descriptors();
   int valid = updated->NumberOfOwnDescriptors();
   if (!updated_descriptors->IsMoreGeneralThan(
           verbatim, valid, descriptors, old_descriptors)) {
-    return Handle<Map>();
+    return MaybeHandle<Map>();
   }
 
   return handle(updated);
 }
 
 
 MaybeHandle<Object> JSObject::SetPropertyWithInterceptor(
     Handle<JSObject> object,
     Handle<Name> name,
     Handle<Object> value,
@@ skipping 1086 matching lines @@
       object, 0, Representation::None(),
       HeapType::None(object->GetIsolate()),
       ALLOW_AS_CONSTANT);
   object->map()->set_migration_target(true);
   if (FLAG_trace_migration) {
     object->PrintInstanceMigration(stdout, *original_map, object->map());
   }
 }
 
 
-Handle<Object> JSObject::TryMigrateInstance(Handle<JSObject> object) {
+// static
+bool JSObject::TryMigrateInstance(Handle<JSObject> object) {
   Handle<Map> original_map(object->map());
-  Handle<Map> new_map = Map::CurrentMapForDeprecatedInternal(original_map);
-  if (new_map.is_null()) return Handle<Object>();
+  Handle<Map> new_map;
+  if (!Map::CurrentMapForDeprecatedInternal(original_map).ToHandle(&new_map)) {
+    return false;
+  }
   JSObject::MigrateToMap(object, new_map);
   if (FLAG_trace_migration) {
     object->PrintInstanceMigration(stdout, *original_map, object->map());
   }
-  return object;
+  return true;
 }
 
 
 MaybeHandle<Object> JSObject::SetPropertyUsingTransition(
     Handle<JSObject> object,
     LookupResult* lookup,
     Handle<Name> name,
     Handle<Object> value,
     PropertyAttributes attributes) {
   Handle<Map> transition_map(lookup->GetTransitionTarget());
@@ skipping 13426 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal