Add last use data flow information to the fast code generator....

src/ast.h

 // Copyright 2006-2008 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 84 matching lines @@
   V(ThisFunction)
 
 #define AST_NODE_LIST(V)                        \
   V(Declaration)                                \
   STATEMENT_NODE_LIST(V)                        \
   EXPRESSION_NODE_LIST(V)
 
 // Forward declarations
 class TargetCollector;
 class MaterializedLiteral;
+class DefinitionInfo;
 
 #define DEF_FORWARD_DECLARATION(type) class type;
 AST_NODE_LIST(DEF_FORWARD_DECLARATION)
 #undef DEF_FORWARD_DECLARATION
 
 
 // Typedef only introduced to avoid unreadable code.
 // Please do appreciate the required space in "> >".
 typedef ZoneList<Handle<String> > ZoneStringList;
 typedef ZoneList<Handle<Object> > ZoneObjectList;
@@ skipping 60 matching lines @@
     // Evaluated for control flow and side effects.  Value is also
     // needed if true.
     kValueTest,
     // Evaluated for control flow and side effects.  Value is also
     // needed if false.
     kTestValue
   };
 
   static const int kNoLabel = -1;
 
-  Expression() : num_(kNoLabel) {}
+  Expression() : num_(kNoLabel), def_(NULL), defined_vars_(NULL) {}
 
   virtual Expression* AsExpression()  { return this; }
 
   virtual bool IsValidLeftHandSide() { return false; }
 
   // Symbols that cannot be parsed as array indices are considered property
   // names.  We do not treat symbols that can be array indexes as property
   // names because [] for string objects is handled only by keyed ICs.
   virtual bool IsPropertyName() { return false; }
 
   // True if the expression does not have (evaluated) subexpressions.
   // Function literals are leaves because their subexpressions are not
   // evaluated.
   virtual bool IsLeaf() { return false; }
 
   // Mark the expression as being compiled as an expression
   // statement. This is used to transform postfix increments to
   // (faster) prefix increments.
   virtual void MarkAsStatement() { /* do nothing */ }
 
   // Static type information for this expression.
   StaticType* type() { return &type_; }
 
   int num() { return num_; }
 
   // AST node numbering ordered by evaluation order.
   void set_num(int n) { num_ = n; }
 
+  // Data flow information.
+  DefinitionInfo* var_def() { return def_; }
+  void set_var_def(DefinitionInfo* def) { def_ = def; }
+
+  ZoneList<DefinitionInfo*>* defined_vars() { return defined_vars_; }
+  void set_defined_vars(ZoneList<DefinitionInfo*>* defined_vars) {
+    defined_vars_ = defined_vars;
+  }
+
  private:
   StaticType type_;
   int num_;
+  DefinitionInfo* def_;
+  ZoneList<DefinitionInfo*>* defined_vars_;
 };
 
 
 /**
  * A sentinel used during pre parsing that represents some expression
  * that is a valid left hand side without having to actually build
  * the expression.
  */
 class ValidLeftHandSideSentinel: public Expression {
  public:
@@ skipping 1601 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_