Extend the maximum size map space...

src/heap.cc

 // Copyright 2009 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 1124 matching lines @@
   map->set_prototype(null_value());
   map->set_constructor(null_value());
   map->set_instance_size(instance_size);
   map->set_inobject_properties(0);
   map->set_pre_allocated_property_fields(0);
   map->set_instance_descriptors(empty_descriptor_array());
   map->set_code_cache(empty_fixed_array());
   map->set_unused_property_fields(0);
   map->set_bit_field(0);
   map->set_bit_field2(0);
+
+  // 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;
 }
 
 
 const Heap::StringTypeTable Heap::string_type_table[] = {
 #define STRING_TYPE_ELEMENT(type, size, name, camel_name)                      \
   {type, size, k##camel_name##MapRootIndex},
   STRING_TYPE_LIST(STRING_TYPE_ELEMENT)
 #undef STRING_TYPE_ELEMENT
 };
@@ skipping 2917 matching lines @@
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 List<Object*> ExternalStringTable::new_space_strings_;
 List<Object*> ExternalStringTable::old_space_strings_;
 
 } }  // namespace v8::internal