Set the code age field of SharedFunctionInfo correctly.

src/mark-compact.cc

 // Copyright 2011 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 994 matching lines @@
   }
 
   inline static bool IsFlushable(Heap* heap, JSFunction* function) {
     SharedFunctionInfo* shared_info = function->unchecked_shared();
 
     // Code is either on stack, in compilation cache or referenced
     // by optimized version of function.
     MarkBit code_mark =
         Marking::MarkBitFrom(function->unchecked_code());
     if (code_mark.Get()) {
-      shared_info->set_code_age(0);
+      if (!Marking::MarkBitFrom(shared_info).Get()) {

[ulan, 2011/11/21 17:36:15]

Do not reset the code age if the shared info visitor already checked for
flushability and possibly updated the code age.

+        shared_info->set_code_age(0);
+      }
       return false;
     }
 
     // We do not flush code for optimized functions.
     if (function->code() != shared_info->unchecked_code()) {
       return false;
     }
 
     return IsFlushable(heap, shared_info);
   }
 
   inline static bool IsFlushable(Heap* heap, SharedFunctionInfo* shared_info) {
     // Code is either on stack, in compilation cache or referenced
     // by optimized version of function.
     MarkBit code_mark =
         Marking::MarkBitFrom(shared_info->unchecked_code());
     if (code_mark.Get()) {
-      shared_info->set_code_age(0);

[ulan, 2011/11/21 17:36:15]

Do not reset the code age, the JSFunction visitor(s) could have checked for
flushability and possibly updated the code age.

       return false;
     }
 
     // The function must be compiled and have the source code available,
     // to be able to recompile it in case we need the function again.
     if (!(shared_info->is_compiled() && HasSourceCode(heap, shared_info))) {
       return false;
     }
 
     // We never flush code for Api functions.
@@ skipping 2730 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal