Reland "Limit the number of transitions allowed per hidden class."

src/heap/mark-compact.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 2503 matching lines @@
       TrimDescriptorArray(map, descriptors, number_of_own_descriptors);
       DCHECK(descriptors->number_of_descriptors() == number_of_own_descriptors);
       map->set_owns_descriptors(true);
     } else {
       DCHECK(descriptors == heap_->empty_descriptor_array());
     }
   }
 
   // Note that we never eliminate a transition array, though we might right-trim
   // such that number_of_transitions() == 0. If this assumption changes,
-  // TransitionArray::CopyInsert() will need to deal with the case that a
-  // transition array disappeared during GC.
-  int trim = t->number_of_transitions() - transition_index;
+  // TransitionArray::Insert() will need to deal with the case that a transition
+  // array disappeared during GC.
+  int trim = t->number_of_transitions_storage() - transition_index;
   if (trim > 0) {
     heap_->RightTrimFixedArray<Heap::FROM_GC>(
         t, t->IsSimpleTransition() ? trim
                                    : trim * TransitionArray::kTransitionSize);
+    t->SetNumberOfTransitions(transition_index);
   }
   DCHECK(map->HasTransitionArray());
 }
 
 
 void MarkCompactCollector::TrimDescriptorArray(Map* map,
                                                DescriptorArray* descriptors,
                                                int number_of_own_descriptors) {
   int number_of_descriptors = descriptors->number_of_descriptors_storage();
   int to_trim = number_of_descriptors - number_of_own_descriptors;
@@ skipping 1910 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }
 }  // namespace v8::internal