Enable preaging of code objects when --optimize-for-size.

src/objects.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 5126 matching lines @@
   DECLARE_PRINTER(Code)
   DECLARE_VERIFIER(Code)
 
   void ClearInlineCaches();
   void ClearTypeFeedbackCells(Heap* heap);
 
   BailoutId TranslatePcOffsetToAstId(uint32_t pc_offset);
 
 #define DECLARE_CODE_AGE_ENUM(X) k##X##CodeAge,
   enum Age {
+    kNotExecutedCodeAge = -2,
+    kExecutedOnceCodeAge = -1,
     kNoAge = 0,
     CODE_AGE_LIST(DECLARE_CODE_AGE_ENUM)
     kAfterLastCodeAge,
     kLastCodeAge = kAfterLastCodeAge - 1,
-    kCodeAgeCount = kAfterLastCodeAge - 1
+    kCodeAgeCount = kAfterLastCodeAge - 1,
+    kPreAgedCodeAge = kQuinquagenarianCodeAge,

[danno, 2013/09/26 16:29:06]

// This is probably clearer if it is kIsOldCodeAge - 1.

[rmcilroy, 2013/09/30 19:38:43]

Done.

+    kIsOldCodeAge = kSexagenarianCodeAge
   };
 #undef DECLARE_CODE_AGE_ENUM
 
   // Code aging.  Indicates how many full GCs this code has survived without
   // being entered through the prologue.  Used to determine when it is
   // relatively safe to flush this code object and replace it with the lazy
   // compilation stub.
   static void MakeCodeAgeSequenceYoung(byte* sequence, Isolate* isolate);
+  static void MarkCodeAsExecuted(byte* sequence, Isolate* isolate);
   void MakeOlder(MarkingParity);
   static bool IsYoungSequence(byte* sequence);
   bool IsOld();
-  int GetAge();
+  Age GetAge();
+  static inline Code* GetPreAgedCodeAgeStub(Isolate* isolate) {
+    return GetCodeAgeStub(isolate, kNotExecutedCodeAge, NO_MARKING_PARITY);
+  }
 
   void PrintDeoptLocation(int bailout_id);
   bool CanDeoptAt(Address pc);
 
 #ifdef VERIFY_HEAP
   void VerifyEmbeddedMapsDependency();
 #endif
 
   // Max loop nesting marker used to postpose OSR. We don't take loop
   // nesting that is deeper than 5 levels into account.
@@ skipping 5075 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_