Age code to allow reclaiming old unexecuted functions

src/code-stubs.h

 // 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 1153 matching lines @@
   virtual bool SometimesSetsUpAFrame() { return false; }
 
   // Generates a call to the entry hook if it's enabled.
   static void MaybeCallEntryHook(MacroAssembler* masm);
 
   // Sets or unsets the entry hook function. Returns true on success,
   // false on an attempt to replace a non-NULL entry hook with another
   // non-NULL hook.
   static bool SetFunctionEntryHook(FunctionEntryHook entry_hook);
 
+  static bool HasEntryHook() { return entry_hook_ != NULL; }
+
  private:
   static void EntryHookTrampoline(intptr_t function,
                                   intptr_t stack_pointer);
 
   Major MajorKey() { return ProfileEntryHook; }
   int MinorKey() { return 0; }
 
   void Generate(MacroAssembler* masm);
 
   // The current function entry hook.
   static FunctionEntryHook entry_hook_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileEntryHookStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_