First steps towards named Litihium operands.

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index b30dd9714daf2ceeae298d775361175b246bb32d..c6f06f511bc052da0dc2d9f5b693c25588d594d5 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -261,8 +261,6 @@ class LInstruction: public ZoneObject {
   virtual bool HasResult() const = 0;
   virtual LOperand* result() = 0;
 
-  virtual int InputCount() = 0;
-  virtual LOperand* InputAt(int i) = 0;
   virtual int TempCount() = 0;
   virtual LOperand* TempAt(int i) = 0;
 
@@ -274,6 +272,11 @@ class LInstruction: public ZoneObject {
 #endif
 
  private:
+  // Iterator support.
+  friend class InputIterator;
+  virtual int InputCount() = 0;
+  virtual LOperand* InputAt(int i) = 0;
+
   LEnvironment* environment_;
   SetOncePointer<LPointerMap> pointer_map_;
   HValue* hydrogen_value_;
@@ -293,7 +296,6 @@ class LTemplateInstruction: public LInstruction {
   void set_result(LOperand* operand) { results_[0] = operand; }
   LOperand* result() { return results_[0]; }
 
-  int InputCount() { return I; }
   LOperand* InputAt(int i) { return inputs_[i]; }
 
   int TempCount() { return T; }
@@ -303,6 +305,9 @@ class LTemplateInstruction: public LInstruction {
   EmbeddedContainer<LOperand*, R> results_;
   EmbeddedContainer<LOperand*, I> inputs_;
   EmbeddedContainer<LOperand*, T> temps_;
+
+ private:
+  virtual int InputCount() { return I; }
 };