Fix issue 571: display descriptive names for code objects from snapshot.

src/mksnapshot.cc

 // Copyright 2006-2008 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 112 matching lines @@
     if (bytes_written_ != 0) {
       fprintf(fp_, ",");
     }
     fprintf(fp_, "%d", byte);
     bytes_written_++;
     if ((bytes_written_ & 0x3f) == 0) {
       fprintf(fp_, "\n");
     }
   }
 
+  virtual int Position() {
+    return bytes_written_;
+  }
+
  private:
   FILE* fp_;
   int bytes_written_;
 };
 
 
 int main(int argc, char** argv) {
 #ifdef ENABLE_LOGGING_AND_PROFILING
   // By default, log code create information in the snapshot.
   i::FLAG_log_code = true;
@@ skipping 17 matching lines @@
   }
   context.Dispose();
   CppByteSink sink(argv[1]);
   i::Serializer ser(&sink);
   // This results in a somewhat smaller snapshot, probably because it gets rid
   // of some things that are cached between garbage collections.
   i::Heap::CollectAllGarbage(true);
   ser.Serialize();
   return 0;
 }