Move DescriptorArray into the map

src/heap.cc

 // Copyright 2012 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 2084 matching lines @@
   map->set_visitor_id(
       StaticVisitorBase::GetVisitorId(instance_type, instance_size));
   map->set_prototype(null_value(), SKIP_WRITE_BARRIER);
   map->set_constructor(null_value(), SKIP_WRITE_BARRIER);
   map->set_instance_size(instance_size);
   map->set_inobject_properties(0);
   map->set_pre_allocated_property_fields(0);
   map->set_code_cache(empty_fixed_array(), SKIP_WRITE_BARRIER);
   map->init_back_pointer(undefined_value());
   map->set_unused_property_fields(0);
+  map->set_instance_descriptors(empty_descriptor_array());
   map->set_bit_field(0);
   map->set_bit_field2(1 << Map::kIsExtensible);
   int bit_field3 = Map::EnumLengthBits::encode(Map::kInvalidEnumCache) |
                    Map::OwnsDescriptors::encode(true);
   map->set_bit_field3(bit_field3);
   map->set_elements_kind(elements_kind);
 
-  // If the map object is aligned fill the padding area with Smi 0 objects.
-  if (Map::kPadStart < Map::kSize) {
-    memset(reinterpret_cast<byte*>(map) + Map::kPadStart - kHeapObjectTag,
-           0,
-           Map::kSize - Map::kPadStart);
-  }
   return map;
 }
 
 
 MaybeObject* Heap::AllocateCodeCache() {
   CodeCache* code_cache;
   { MaybeObject* maybe_code_cache = AllocateStruct(CODE_CACHE_TYPE);
     if (!maybe_code_cache->To(&code_cache)) return maybe_code_cache;
   }
   code_cache->set_default_cache(empty_fixed_array(), SKIP_WRITE_BARRIER);
@@ skipping 106 matching lines @@
 
   // Allocate the empty descriptor array.
   { MaybeObject* maybe_obj = AllocateEmptyFixedArray();
     if (!maybe_obj->ToObject(&obj)) return false;
   }
   set_empty_descriptor_array(DescriptorArray::cast(obj));
 
   // Fix the instance_descriptors for the existing maps.
   meta_map()->set_code_cache(empty_fixed_array());
   meta_map()->init_back_pointer(undefined_value());
+  meta_map()->set_instance_descriptors(empty_descriptor_array());
 
   fixed_array_map()->set_code_cache(empty_fixed_array());
   fixed_array_map()->init_back_pointer(undefined_value());
+  fixed_array_map()->set_instance_descriptors(empty_descriptor_array());
 
   oddball_map()->set_code_cache(empty_fixed_array());
   oddball_map()->init_back_pointer(undefined_value());
+  oddball_map()->set_instance_descriptors(empty_descriptor_array());
 
   // Fix prototype object for existing maps.
   meta_map()->set_prototype(null_value());
   meta_map()->set_constructor(null_value());
 
   fixed_array_map()->set_prototype(null_value());
   fixed_array_map()->set_constructor(null_value());
 
   oddball_map()->set_prototype(null_value());
   oddball_map()->set_constructor(null_value());
@@ skipping 1689 matching lines @@
       }
       descriptors->Sort();
 
       // The descriptors may contain duplicates because the compiler does not
       // guarantee the uniqueness of property names (it would have required
       // quadratic time). Once the descriptors are sorted we can check for
       // duplicates in linear time.
       if (HasDuplicates(descriptors)) {
         fun->shared()->ForbidInlineConstructor();
       } else {
-        MaybeObject* maybe_failure = map->InitializeDescriptors(descriptors);
-        if (maybe_failure->IsFailure()) return maybe_failure;
+        map->InitializeDescriptors(descriptors);
         map->set_pre_allocated_property_fields(count);
         map->set_unused_property_fields(in_object_properties - count);
       }
     }
   }
 
   fun->shared()->StartInobjectSlackTracking(map);
 
   return map;
 }
@@ skipping 3369 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   memcpy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   memcpy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal