[turbofan] Avoid unnecessary write barriers and improve code generation.

src/compiler/code-generator-impl.h

Index: src/compiler/code-generator-impl.h
diff --git a/src/compiler/code-generator-impl.h b/src/compiler/code-generator-impl.h
index 45f77913bd383837ac64aabc644a87a58080577d..b801bdfc70c19b568f06162c8f87b4953e6b0198 100644
--- a/src/compiler/code-generator-impl.h
+++ b/src/compiler/code-generator-impl.h
@@ -147,12 +147,15 @@ class OutOfLineCode : public ZoneObject {
 
   Label* entry() { return &entry_; }
   Label* exit() { return &exit_; }
+  Frame* frame() const { return frame_; }
+  Isolate* isolate() const { return masm()->isolate(); }
   MacroAssembler* masm() const { return masm_; }
   OutOfLineCode* next() const { return next_; }
 
  private:
   Label entry_;
   Label exit_;
+  Frame* const frame_;
   MacroAssembler* const masm_;
   OutOfLineCode* const next_;
 };