Fix compile errors on 64 bit platforms.

src/heap.cc

 // 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 5658 matching lines @@
 intptr_t Heap::PromotedSpaceSizeOfObjects() {
   return old_pointer_space_->SizeOfObjects()
       + old_data_space_->SizeOfObjects()
       + code_space_->SizeOfObjects()
       + map_space_->SizeOfObjects()
       + cell_space_->SizeOfObjects()
       + lo_space_->SizeOfObjects();
 }
 
 
-int Heap::PromotedExternalMemorySize() {
+intptr_t Heap::PromotedExternalMemorySize() {
   if (amount_of_external_allocated_memory_
       <= amount_of_external_allocated_memory_at_last_global_gc_) return 0;
   return amount_of_external_allocated_memory_
       - amount_of_external_allocated_memory_at_last_global_gc_;
 }
 
 #ifdef DEBUG
 
 // Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
 static const int kMarkTag = 2;
@@ skipping 1290 matching lines @@
   } else {
     p ^= 0x1d1ed & (Page::kPageSize - 1);  // I died.
   }
   remembered_unmapped_pages_[remembered_unmapped_pages_index_] =
       reinterpret_cast<Address>(p);
   remembered_unmapped_pages_index_++;
   remembered_unmapped_pages_index_ %= kRememberedUnmappedPages;
 }
 
 } }  // namespace v8::internal