Track Hydrogen statistics on a per-Isolate basis

src/hydrogen-instructions.cc

 // 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 60 matching lines @@
 int HValue::LoopWeight() const {
   const int w = FLAG_loop_weight;
   static const int weights[] = { 1, w, w*w, w*w*w, w*w*w*w };
   return weights[Min(block()->LoopNestingDepth(),
                      static_cast<int>(ARRAY_SIZE(weights)-1))];
 }
 
 
 Isolate* HValue::isolate() const {
   ASSERT(block() != NULL);
-  return block()->graph()->isolate();
+  return block()->isolate();
 }
 
 
 void HValue::AssumeRepresentation(Representation r) {
   if (CheckFlag(kFlexibleRepresentation)) {
     ChangeRepresentation(r);
     // The representation of the value is dictated by type feedback and
     // will not be changed later.
     ClearFlag(kFlexibleRepresentation);
   }
@@ skipping 3175 matching lines @@
 
 
 void HCheckFunction::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal