Add bit_field3 to Map objects

src/objects-inl.h

 // Copyright 2011 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 1656 matching lines @@
   WRITE_FIELD(this, kHeaderSize + index * kPointerSize, heap->null_value());
 }
 
 
 Object** FixedArray::data_start() {
   return HeapObject::RawField(this, kHeaderSize);
 }
 
 
 bool DescriptorArray::IsEmpty() {
-  ASSERT(this->length() > kFirstIndex ||
+  ASSERT(this->IsSmi() ||
+         this->length() > kFirstIndex ||
          this == HEAP->empty_descriptor_array());
-  return length() <= kFirstIndex;
+  return this->IsSmi() || length() <= kFirstIndex;
 }
 
 
+int DescriptorArray::bit_field3_storage() {
+  Object* storage = READ_FIELD(this, kBitField3StorageOffset);
+  return Smi::cast(storage)->value();
+}
+
+void DescriptorArray::set_bit_field3_storage(int value) {
+  ASSERT(!IsEmpty());
+  WRITE_FIELD(this, kBitField3StorageOffset, Smi::FromInt(value));
+}
+
+
 void DescriptorArray::fast_swap(FixedArray* array, int first, int second) {
   Object* tmp = array->get(first);
   fast_set(array, first, array->get(second));
   fast_set(array, second, tmp);
 }
 
 
 int DescriptorArray::Search(String* name) {
   SLOW_ASSERT(IsSortedNoDuplicates());
 
@@ skipping 1267 matching lines @@
   { MaybeObject* maybe_obj = CopyDropTransitions();
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
   Map* new_map = Map::cast(obj);
   new_map->set_has_fast_elements(false);
   isolate()->counters()->map_fast_to_slow_elements()->Increment();
   return new_map;
 }
 
 
-ACCESSORS(Map, instance_descriptors, DescriptorArray,
-          kInstanceDescriptorsOffset)
+DescriptorArray* Map::instance_descriptors() {
+  Object* object = READ_FIELD(this, kInstanceDescriptorsOrBitField3Offset);
+  if (object->IsSmi()) {
+    return HEAP->empty_descriptor_array();
+  } else {
+    return DescriptorArray::cast(object);
+  }
+}
+
+
+void Map::init_instance_descriptors() {
+  WRITE_FIELD(this, kInstanceDescriptorsOrBitField3Offset, Smi::FromInt(0));
+}
+
+
+void Map::clear_instance_descriptors() {
+  Object* object = READ_FIELD(this,
+                              kInstanceDescriptorsOrBitField3Offset);
+  if (!object->IsSmi()) {
+    WRITE_FIELD(
+        this,
+        kInstanceDescriptorsOrBitField3Offset,
+        Smi::FromInt(DescriptorArray::cast(object)->bit_field3_storage()));
+  }
+}
+
+
+void Map::set_instance_descriptors(DescriptorArray* value,
+                                   WriteBarrierMode mode) {
+  Object* object = READ_FIELD(this,
+                              kInstanceDescriptorsOrBitField3Offset);
+  if (value == isolate()->heap()->empty_descriptor_array()) {
+    clear_instance_descriptors();
+    return;
+  } else {
+    if (object->IsSmi()) {
+      value->set_bit_field3_storage(Smi::cast(object)->value());
+    } else {
+      value->set_bit_field3_storage(
+          DescriptorArray::cast(object)->bit_field3_storage());
+    }
+  }
+  ASSERT(!is_shared());
+  WRITE_FIELD(this, kInstanceDescriptorsOrBitField3Offset, value);
+  CONDITIONAL_WRITE_BARRIER(GetHeap(),
+                            this,
+                            kInstanceDescriptorsOrBitField3Offset,
+                            mode);
+}
+
+
+int Map::bit_field3() {
+  Object* object = READ_FIELD(this,
+                              kInstanceDescriptorsOrBitField3Offset);
+  if (object->IsSmi()) {
+    return Smi::cast(object)->value();
+  } else {
+    return DescriptorArray::cast(object)->bit_field3_storage();
+  }
+}
+
+
+void Map::set_bit_field3(int value) {
+  ASSERT(Smi::IsValid(value));
+  Object* object = READ_FIELD(this,
+                              kInstanceDescriptorsOrBitField3Offset);
+  if (object->IsSmi()) {
+    WRITE_FIELD(this,
+                kInstanceDescriptorsOrBitField3Offset,
+                Smi::FromInt(value));
+  } else {
+    DescriptorArray::cast(object)->set_bit_field3_storage(value);
+  }
+}
+
+
 ACCESSORS(Map, code_cache, Object, kCodeCacheOffset)
 ACCESSORS(Map, prototype_transitions, FixedArray, kPrototypeTransitionsOffset)
 ACCESSORS(Map, constructor, Object, kConstructorOffset)
 
 ACCESSORS(JSFunction, shared, SharedFunctionInfo, kSharedFunctionInfoOffset)
 ACCESSORS(JSFunction, literals, FixedArray, kLiteralsOffset)
 ACCESSORS_GCSAFE(JSFunction, next_function_link, Object,
                  kNextFunctionLinkOffset)
 
 ACCESSORS(GlobalObject, builtins, JSBuiltinsObject, kBuiltinsOffset)
@@ skipping 1246 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_