Remove variable rewrites and the unneccesary Slot class.

src/ast.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 147 matching lines @@
   virtual type* As##type() { return NULL; }
   AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
 #undef DECLARE_NODE_FUNCTIONS
 
   virtual Statement* AsStatement() { return NULL; }
   virtual Expression* AsExpression() { return NULL; }
   virtual TargetCollector* AsTargetCollector() { return NULL; }
   virtual BreakableStatement* AsBreakableStatement() { return NULL; }
   virtual IterationStatement* AsIterationStatement() { return NULL; }
   virtual MaterializedLiteral* AsMaterializedLiteral() { return NULL; }
-  virtual Slot* AsSlot() { return NULL; }
 
   // True if the node is simple enough for us to inline calls containing it.
   virtual bool IsInlineable() const = 0;
 
   static int Count() { return Isolate::Current()->ast_node_count(); }
   static void ResetIds() { Isolate::Current()->set_ast_node_id(0); }
 
  protected:
   static unsigned GetNextId(Isolate* isolate) {
     return ReserveIdRange(isolate, 1);
@@ skipping 940 matching lines @@
   int first_element_id_;
 };
 
 
 class VariableProxy: public Expression {
  public:
   VariableProxy(Isolate* isolate, Variable* var);
 
   DECLARE_NODE_TYPE(VariableProxy)
 
-  // Type testing & conversion
-  Variable* AsVariable() { return (this == NULL) ? NULL : var_; }
-
   virtual bool IsValidLeftHandSide() {
     return var_ == NULL ? true : var_->IsValidLeftHandSide();
   }
 
   virtual bool IsTrivial() {
     // Reading from a mutable variable is a side effect, but the
     // variable for 'this' is immutable.
     return is_this_ || is_trivial_;
   }
 
   virtual bool IsInlineable() const;
 
   bool IsVariable(Handle<String> n) {
     return !is_this() && name().is_identical_to(n);
   }
 
-  bool IsArguments() {
-    Variable* variable = AsVariable();
-    return (variable == NULL) ? false : variable->is_arguments();
-  }
+  bool IsArguments() { return var_ != NULL && var_->is_arguments(); }
 
   Handle<String> name() const { return name_; }
   Variable* var() const { return var_; }
   bool is_this() const { return is_this_; }
   bool inside_with() const { return inside_with_; }
   int position() const { return position_; }
 
   void MarkAsTrivial() { is_trivial_ = true; }
 
   // Bind this proxy to the variable var.
@@ skipping 23 matching lines @@
   virtual bool IsValidLeftHandSide() { return !is_this(); }
 
  private:
   VariableProxySentinel(Isolate* isolate, bool is_this)
       : VariableProxy(isolate, is_this) { }
 
   friend class AstSentinels;
 };
 
 
-class Slot: public Expression {
- public:
-  enum Type {
-    // A slot in the parameter section on the stack. index() is
-    // the parameter index, counting left-to-right, starting at 0.
-    PARAMETER,
-
-    // A slot in the local section on the stack. index() is
-    // the variable index in the stack frame, starting at 0.
-    LOCAL,
-
-    // An indexed slot in a heap context. index() is the
-    // variable index in the context object on the heap,
-    // starting at 0. var()->scope() is the corresponding
-    // scope.
-    CONTEXT,
-
-    // A named slot in a heap context. var()->name() is the
-    // variable name in the context object on the heap,
-    // with lookup starting at the current context. index()
-    // is invalid.
-    LOOKUP
-  };
-
-  Slot(Isolate* isolate, Variable* var, Type type, int index)
-      : Expression(isolate), var_(var), type_(type), index_(index) {
-    ASSERT(var != NULL);
-  }
-
-  virtual void Accept(AstVisitor* v);
-
-  virtual Slot* AsSlot() { return this; }
-
-  bool IsStackAllocated() { return type_ == PARAMETER || type_ == LOCAL; }
-
-  // Accessors
-  Variable* var() const { return var_; }
-  Type type() const { return type_; }
-  int index() const { return index_; }
-  bool is_arguments() const { return var_->is_arguments(); }
-  virtual bool IsInlineable() const;
-
- private:
-  Variable* var_;
-  Type type_;
-  int index_;
-};
-
-
 class Property: public Expression {
  public:
   Property(Isolate* isolate,
            Expression* obj,
            Expression* key,
            int pos)
       : Expression(isolate),
         obj_(obj),
         key_(key),
         pos_(pos),
@@ skipping 990 matching lines @@
   // Stack overflow tracking support.
   bool HasStackOverflow() const { return stack_overflow_; }
   bool CheckStackOverflow();
 
   // If a stack-overflow exception is encountered when visiting a
   // node, calling SetStackOverflow will make sure that the visitor
   // bails out without visiting more nodes.
   void SetStackOverflow() { stack_overflow_ = true; }
   void ClearStackOverflow() { stack_overflow_ = false; }
 
-  // Nodes not appearing in the AST, including slots.
-  virtual void VisitSlot(Slot* node) { UNREACHABLE(); }
-
   // Individual AST nodes.
 #define DEF_VISIT(type)                         \
   virtual void Visit##type(type* node) = 0;
   AST_NODE_LIST(DEF_VISIT)
 #undef DEF_VISIT
 
  protected:
   Isolate* isolate() { return isolate_; }
 
  private:
   Isolate* isolate_;
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_