Do not inline array resize operations for outdated prototype maps.

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/objects.h"
 
 #include <iomanip>
 #include <sstream>
 
 #include "src/accessors.h"
@@ skipping 1758 matching lines @@
   // registers with its new prototype now. This preserves the invariant that
   // when a map on a prototype chain is registered with its prototype, then
   // all prototypes further up the chain are also registered with their
   // respective prototypes.
   UpdatePrototypeUserRegistration(old_map, new_map, new_map->GetIsolate());
 
   if (object->HasFastProperties()) {
     if (!new_map->is_dictionary_map()) {
       MigrateFastToFast(object, new_map);
       if (old_map->is_prototype_map()) {
+        DCHECK(!old_map->is_stable());
+        DCHECK(new_map->is_stable());
         // Clear out the old descriptor array to avoid problems to sharing
         // the descriptor array without using an explicit.
         old_map->InitializeDescriptors(
             old_map->GetHeap()->empty_descriptor_array(),
             LayoutDescriptor::FastPointerLayout());
         // Ensure that no transition was inserted for prototype migrations.
         DCHECK_EQ(0, TransitionArray::NumberOfTransitions(
                          old_map->raw_transitions()));
         DCHECK(new_map->GetBackPointer()->IsUndefined());
       }
@@ skipping 13879 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8