Age the number string cache so it does not keep strings

src/heap.h

 // 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 1401 matching lines @@
     scavenging_visitors_table_.GetVisitor(map)(map, slot, obj);
   }
 
   void QueueMemoryChunkForFree(MemoryChunk* chunk);
   void FreeQueuedChunks();
 
   // Completely clear the Instanceof cache (to stop it keeping objects alive
   // around a GC).
   inline void CompletelyClearInstanceofCache();
 
+  // Constants for the NumberStringCache.
+  static const int kNSCUnusedAge = -1;

[Vyacheslav Egorov (Chromium), 2011/10/18 15:30:39]

I don't think abbreviation NSC is good.

+  static const int kNSCMinAge = 0;
+  static const int kNSCMaxAge = 2;
+  static const int kNSCNumberOffset = 0;
+  static const int kNSCStringOffset = 1;
+  static const int kNSCAgeOffset = 2;
+  static const int kNSCSlotsPerEntry = 3;
+
  private:
   Heap();
 
   // This can be calculated directly from a pointer to the heap; however, it is
   // more expedient to get at the isolate directly from within Heap methods.
   Isolate* isolate_;
 
   intptr_t code_range_size_;
   int reserved_semispace_size_;
   int max_semispace_size_;
@@ skipping 249 matching lines @@
 
   // Total RegExp code ever generated
   double total_regexp_code_generated_;
 
   GCTracer* tracer_;
 
 
   // Initializes the number to string cache based on the max semispace size.
   MUST_USE_RESULT MaybeObject* InitializeNumberStringCache();
   // Flush the number to string cache.
-  void FlushNumberStringCache();
+  void AgeNumberStringCache();
 
   void UpdateSurvivalRateTrend(int start_new_space_size);
 
   enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
 
   static const int kYoungSurvivalRateThreshold = 90;
   static const int kYoungSurvivalRateAllowedDeviation = 15;
 
   int young_survivors_after_last_gc_;
   int high_survival_rate_period_length_;
@@ skipping 766 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_