[runtime] Ensure that all elements kind transitions are chained to the root map.

src/objects-inl.h

 // Copyright 2012 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
 
 #ifndef V8_OBJECTS_INL_H_
 #define V8_OBJECTS_INL_H_
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/contexts-inl.h"
 #include "src/conversions-inl.h"
 #include "src/factory.h"
 #include "src/field-index-inl.h"
+#include "src/field-type.h"
 #include "src/handles-inl.h"
 #include "src/heap/heap-inl.h"
 #include "src/heap/heap.h"
 #include "src/isolate-inl.h"
 #include "src/isolate.h"
 #include "src/keys.h"
 #include "src/layout-descriptor-inl.h"
 #include "src/lookup.h"
 #include "src/objects.h"
 #include "src/property.h"
@@ skipping 2772 matching lines @@
     FixedTypedArrayBase* empty_array =
         GetHeap()->EmptyFixedTypedArrayForMap(this);
     DCHECK(!GetHeap()->InNewSpace(empty_array));
     return empty_array;
   } else {
     UNREACHABLE();
   }
   return NULL;
 }
 
+// static
+Handle<Map> Map::ReconfigureProperty(Handle<Map> map, int modify_index,
+                                     PropertyKind new_kind,
+                                     PropertyAttributes new_attributes,
+                                     Representation new_representation,
+                                     Handle<FieldType> new_field_type,
+                                     StoreMode store_mode) {
+  return Reconfigure(map, map->elements_kind(), modify_index, new_kind,
+                     new_attributes, new_representation, new_field_type,
+                     store_mode);
+}
+
+// static
+Handle<Map> Map::ReconfigureElementsKind(Handle<Map> map,
+                                         ElementsKind new_elements_kind) {
+  return Reconfigure(map, new_elements_kind, -1, kData, NONE,
+                     Representation::None(), FieldType::None(map->GetIsolate()),
+                     ALLOW_IN_DESCRIPTOR);
+}
 
 Object** DescriptorArray::GetKeySlot(int descriptor_number) {
   DCHECK(descriptor_number < number_of_descriptors());
   return RawFieldOfElementAt(ToKeyIndex(descriptor_number));
 }
 
 
 Object** DescriptorArray::GetDescriptorStartSlot(int descriptor_number) {
   return GetKeySlot(descriptor_number);
 }
@@ skipping 5023 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_