Simplify and fix code aging.

src/codegen.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 89 matching lines @@
 
   // Allocate and install the code.
   CodeDesc desc;
   masm->GetCode(&desc);
   Handle<Code> code =
       isolate->factory()->NewCode(desc, flags, masm->CodeObject());
 
   if (!code.is_null()) {
     isolate->counters()->total_compiled_code_size()->Increment(
         code->instruction_size());
+    code->set_prologue_offset(info->prologue_offset());
   }
   return code;
 }
 
 
 void CodeGenerator::PrintCode(Handle<Code> code, CompilationInfo* info) {
 #ifdef ENABLE_DISASSEMBLER
   bool print_code = Isolate::Current()->bootstrapper()->IsActive()
       ? FLAG_print_builtin_code
       : (FLAG_print_code || (info->IsOptimizing() && FLAG_print_opt_code));
@@ skipping 82 matching lines @@
   ASSERT(result_size_ == 1 || result_size_ == 2);
 #ifdef _WIN64
   return result | ((result_size_ == 1) ? 0 : 2);
 #else
   return result;
 #endif
 }
 
 
 } }  // namespace v8::internal