Migrate to current map if deprecated in SetProperty

src/objects.cc

 // Copyright 2013 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/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 7307 matching lines @@
   UNREACHABLE();
   return false;
 }
 
 
 Handle<Map> Map::PrepareForDataProperty(Handle<Map> map, int descriptor,
                                         Handle<Object> value) {
   // Dictionaries can store any property value.
   if (map->is_dictionary_map()) return map;
 
+  // Migrate to the newest map before storing the property.
+  if (map->is_deprecated()) {
+    map = GeneralizeRepresentation(map, 0, Representation::None(),
+                                   HeapType::None(map->GetIsolate()),
+                                   ALLOW_AS_CONSTANT);
+  }
+
   Handle<DescriptorArray> descriptors(map->instance_descriptors());
 
   if (descriptors->CanHoldValue(descriptor, *value)) return map;
 
   Isolate* isolate = map->GetIsolate();
   Representation representation = value->OptimalRepresentation();
   Handle<HeapType> type = value->OptimalType(isolate, representation);
 
   return GeneralizeRepresentation(map, descriptor, representation, type,
                                   FORCE_FIELD);
 }
 
 
 Handle<Map> Map::TransitionToDataProperty(Handle<Map> map, Handle<Name> name,
                                           Handle<Object> value,
                                           PropertyAttributes attributes,
                                           StoreFromKeyed store_mode) {
-  // Cannot currently handle deprecated maps.
-  ASSERT(!map->is_deprecated());
   // Dictionary maps can always have additional data properties.
   if (map->is_dictionary_map()) return map;
 
+  // Migrate to the newest map before transitioning to the new property.
+  if (map->is_deprecated()) {
+    map = GeneralizeRepresentation(map, 0, Representation::None(),
+                                   HeapType::None(map->GetIsolate()),
+                                   ALLOW_AS_CONSTANT);
+  }
+
   int index = map->SearchTransition(*name);
   if (index != TransitionArray::kNotFound) {
     Handle<Map> transition(map->GetTransition(index));
     int descriptor = transition->LastAdded();
 
     // TODO(verwaest): Handle attributes better.
     DescriptorArray* descriptors = transition->instance_descriptors();
     if (descriptors->GetDetails(descriptor).attributes() != attributes) {
       return CopyGeneralizeAllRepresentations(transition, descriptor,
                                               FORCE_FIELD, attributes,
@@ skipping 9588 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