Verify a bit more about external strings

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 3450 matching lines @@
   return READ_FIELD(this, kSecondOffset);
 }
 
 
 void ConsString::set_second(String* value, WriteBarrierMode mode) {
   WRITE_FIELD(this, kSecondOffset, value);
   CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kSecondOffset, value, mode);
 }
 
 
+const void* ExternalString::resource_data() const {
+  return *reinterpret_cast<const void* const*>(
+             FIELD_ADDR_CONST(this, kResourceDataOffset));
+}
+
+
 bool ExternalString::is_short() {
   InstanceType type = map()->instance_type();
   return (type & kShortExternalStringMask) == kShortExternalStringTag;
 }
 
 
-const ExternalOneByteString::Resource* ExternalOneByteString::resource() {
-  return *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset));
+const ExternalOneByteString::Resource* ExternalOneByteString::resource() const {
+  return *reinterpret_cast<const Resource* const*>(
+             FIELD_ADDR_CONST(this, kResourceOffset));
 }
 
 
 void ExternalOneByteString::update_data_cache() {
   if (is_short()) return;
   const char** data_field =
       reinterpret_cast<const char**>(FIELD_ADDR(this, kResourceDataOffset));
   *data_field = resource()->data();
 }
 
@@ skipping 11 matching lines @@
   return reinterpret_cast<const uint8_t*>(resource()->data());
 }
 
 
 uint16_t ExternalOneByteString::ExternalOneByteStringGet(int index) {
   DCHECK(index >= 0 && index < length());
   return GetChars()[index];
 }
 
 
-const ExternalTwoByteString::Resource* ExternalTwoByteString::resource() {
-  return *reinterpret_cast<Resource**>(FIELD_ADDR(this, kResourceOffset));
+const ExternalTwoByteString::Resource* ExternalTwoByteString::resource() const {
+  return *reinterpret_cast<const Resource* const*>(
+             FIELD_ADDR_CONST(this, kResourceOffset));
 }
 
 
 void ExternalTwoByteString::update_data_cache() {
   if (is_short()) return;
   const uint16_t** data_field =
       reinterpret_cast<const uint16_t**>(FIELD_ADDR(this, kResourceDataOffset));
   *data_field = resource()->data();
 }
 
@@ skipping 3853 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_