[strong] Introduce strong bit

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.
 //
@@ skipping 4697 matching lines @@
 void Map::set_migration_target(bool value) {
   set_bit_field3(IsMigrationTarget::update(bit_field3(), value));
 }
 
 
 bool Map::is_migration_target() {
   return IsMigrationTarget::decode(bit_field3());
 }
 
 
+void Map::set_is_strong(bool value) {
+  set_bit_field3(IsStrong::update(bit_field3(), value));
+}
+
+
+bool Map::is_strong() {
+  return IsStrong::decode(bit_field3());
+}
+
+
 void Map::set_counter(int value) {
   set_bit_field3(Counter::update(bit_field3(), value));
 }
 
 
 int Map::counter() { return Counter::decode(bit_field3()); }
 
 
 void Map::mark_unstable() {
   set_bit_field3(IsUnstable::update(bit_field3(), true));
@@ skipping 2879 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_