Reland r11425 "Re-enable optimization for hot functions that have optimization disabled due to many…

src/heap.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 1579 matching lines @@
   // For post mortem debugging.
   void RememberUnmappedPage(Address page, bool compacted);
 
   // Global inline caching age: it is incremented on some GCs after context
   // disposal. We use it to flush inline caches.
   int global_ic_age() {
     return global_ic_age_;
   }
 
   void AgeInlineCaches() {
-    ++global_ic_age_;
+    const int kMaxICAge = SharedFunctionInfo::kICAgeMask;
+    global_ic_age_ = global_ic_age_ < kMaxICAge ? global_ic_age_ + 1 : 0;

[Jakob Kummerow, 2012/06/11 12:13:59]

I guess it doesn't really matter, but the following would be slightly faster:
ASSERT((kMaxICAge & (kMaxICAge+1)) == 0);  // kMaxICAge is (2^n)-1.
global_ic_age_ = (global_ic_age_ + 1) & kMaxICAge;

[ulan, 2012/06/11 16:07:31]

Done. Left out ASSERT, since BitField<> guarantees that kMax is 2^n-1.

   }
 
  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_;
 
   Object* roots_[kRootListLength];
@@ skipping 1090 matching lines @@
   AssertNoAllocation no_alloc;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_