The check for internalized strings relied on the fact that we had less

src/objects-inl.h

 // 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 203 matching lines @@
 bool Object::IsSpecFunction() {
   if (!Object::IsHeapObject()) return false;
   InstanceType type = HeapObject::cast(this)->map()->instance_type();
   return type == JS_FUNCTION_TYPE || type == JS_FUNCTION_PROXY_TYPE;
 }
 
 
 bool Object::IsInternalizedString() {
   if (!this->IsHeapObject()) return false;
   uint32_t type = HeapObject::cast(this)->map()->instance_type();
-  // Because the internalized tag is non-zero and no non-string types have the
-  // internalized bit set we can test for internalized strings with a very
-  // simple test operation.
   STATIC_ASSERT(kInternalizedTag != 0);
-  ASSERT(kNotStringTag + kIsInternalizedMask > LAST_TYPE);
-  return (type & kIsInternalizedMask) != 0;
+  return (type & (kIsNotStringMask | kIsInternalizedMask)) ==
+      (kInternalizedTag | kStringTag);
 }
 
 
 bool Object::IsConsString() {
   if (!IsString()) return false;
   return StringShape(String::cast(this)).IsCons();
 }
 
 
 bool Object::IsSlicedString() {
@@ skipping 76 matching lines @@
 StringShape::StringShape(InstanceType t)
   : type_(static_cast<uint32_t>(t)) {
   set_valid();
   ASSERT((type_ & kIsNotStringMask) == kStringTag);
 }
 
 
 bool StringShape::IsInternalized() {
   ASSERT(valid());
   STATIC_ASSERT(kInternalizedTag != 0);
-  return (type_ & kIsInternalizedMask) != 0;
+  return (type_ & (kIsNotStringMask | kIsInternalizedMask)) ==
+      (kInternalizedTag | kStringTag);
 }
 
 
 bool String::IsOneByteRepresentation() {
   uint32_t type = map()->instance_type();
   return (type & kStringEncodingMask) == kOneByteStringTag;
 }
 
 
 bool String::IsTwoByteRepresentation() {
@@ skipping 3044 matching lines @@
 
 
 int Map::pre_allocated_property_fields() {
   return READ_BYTE_FIELD(this, kPreAllocatedPropertyFieldsOffset);
 }
 
 
 int HeapObject::SizeFromMap(Map* map) {
   int instance_size = map->instance_size();
   if (instance_size != kVariableSizeSentinel) return instance_size;
-  // We can ignore the "internalized" bit because it is only set for strings
-  // and thus implies a string type.
-  int instance_type =
-      static_cast<int>(map->instance_type()) & ~kIsInternalizedMask;
   // Only inline the most frequent cases.
+  int instance_type = static_cast<int>(map->instance_type());
   if (instance_type == FIXED_ARRAY_TYPE) {
     return FixedArray::BodyDescriptor::SizeOf(map, this);
   }
-  if (instance_type == ASCII_STRING_TYPE) {
+  if (instance_type == ASCII_STRING_TYPE ||
+      instance_type == ASCII_INTERNALIZED_STRING_TYPE) {
     return SeqOneByteString::SizeFor(
         reinterpret_cast<SeqOneByteString*>(this)->length());
   }
   if (instance_type == BYTE_ARRAY_TYPE) {
     return reinterpret_cast<ByteArray*>(this)->ByteArraySize();
   }
   if (instance_type == FREE_SPACE_TYPE) {
     return reinterpret_cast<FreeSpace*>(this)->size();
   }
-  if (instance_type == STRING_TYPE) {
+  if (instance_type == STRING_TYPE ||
+      instance_type == INTERNALIZED_STRING_TYPE) {
     return SeqTwoByteString::SizeFor(
         reinterpret_cast<SeqTwoByteString*>(this)->length());
   }
   if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
     return FixedDoubleArray::SizeFor(
         reinterpret_cast<FixedDoubleArray*>(this)->length());
   }
   ASSERT(instance_type == CODE_TYPE);
   return reinterpret_cast<Code*>(this)->CodeSize();
 }
@@ skipping 2770 matching lines @@
 #undef WRITE_UINT32_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_