Introduce code flushing of RegExp code.

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 1238 matching lines @@
   int get_min_in_mutator() { return min_in_mutator_; }
 
   MarkCompactCollector* mark_compact_collector() {
     return &mark_compact_collector_;
   }
 
   ExternalStringTable* external_string_table() {
     return &external_string_table_;
   }
 
+  // Returns the current sweep generation.
+  int sweep_generation() {
+    return sweep_generation_;
+  }
+
   inline Isolate* isolate();
   bool is_safe_to_read_maps() { return is_safe_to_read_maps_; }
 
   void CallGlobalGCPrologueCallback() {
     if (global_gc_prologue_callback_ != NULL) global_gc_prologue_callback_();
   }
 
   void CallGlobalGCEpilogueCallback() {
     if (global_gc_epilogue_callback_ != NULL) global_gc_epilogue_callback_();
   }
 
  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_;
 
   int reserved_semispace_size_;
   int max_semispace_size_;
   int initial_semispace_size_;
   intptr_t max_old_generation_size_;
   intptr_t max_executable_size_;
   intptr_t code_range_size_;
 
   // For keeping track of how much data has survived
   // scavenge since last new space expansion.
   int survived_since_last_expansion_;
 
+  // For keeping track on when to flush RegExp code.
+  int sweep_generation_;
+
   int always_allocate_scope_depth_;
   int linear_allocation_scope_depth_;
 
   // For keeping track of context disposals.
   int contexts_disposed_;
 
 #if defined(V8_TARGET_ARCH_X64)
   static const int kMaxObjectSizeInNewSpace = 1024*KB;
 #else
   static const int kMaxObjectSizeInNewSpace = 512*KB;
@@ skipping 994 matching lines @@
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_