Merge changes up to V8 version 2.1.3 into the partial snapshots

src/ast.h

 // Copyright 2010 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 99 matching lines @@
 
 
 // Typedef only introduced to avoid unreadable code.
 // Please do appreciate the required space in "> >".
 typedef ZoneList<Handle<String> > ZoneStringList;
 typedef ZoneList<Handle<Object> > ZoneObjectList;
 
 
 class AstNode: public ZoneObject {
  public:
+  static const int kNoNumber = -1;
+
+  AstNode() : num_(kNoNumber) {}
   virtual ~AstNode() { }
   virtual void Accept(AstVisitor* v) = 0;
 
   // Type testing & conversion.
   virtual Statement* AsStatement() { return NULL; }
   virtual ExpressionStatement* AsExpressionStatement() { return NULL; }
   virtual EmptyStatement* AsEmptyStatement() { return NULL; }
   virtual Expression* AsExpression() { return NULL; }
   virtual Literal* AsLiteral() { return NULL; }
   virtual Slot* AsSlot() { return NULL; }
   virtual VariableProxy* AsVariableProxy() { return NULL; }
   virtual Property* AsProperty() { return NULL; }
   virtual Call* AsCall() { return NULL; }
   virtual TargetCollector* AsTargetCollector() { return NULL; }
   virtual BreakableStatement* AsBreakableStatement() { return NULL; }
   virtual IterationStatement* AsIterationStatement() { return NULL; }
   virtual UnaryOperation* AsUnaryOperation() { return NULL; }
   virtual BinaryOperation* AsBinaryOperation() { return NULL; }
   virtual Assignment* AsAssignment() { return NULL; }
   virtual FunctionLiteral* AsFunctionLiteral() { return NULL; }
   virtual MaterializedLiteral* AsMaterializedLiteral() { return NULL; }
   virtual ObjectLiteral* AsObjectLiteral() { return NULL; }
   virtual ArrayLiteral* AsArrayLiteral() { return NULL; }
   virtual CompareOperation* AsCompareOperation() { return NULL; }
+
+  int num() { return num_; }
+  void set_num(int n) { num_ = n; }
+
+ private:
+  // Support for ast node numbering.
+  int num_;
 };
 
 
 class Statement: public AstNode {
  public:
   Statement() : statement_pos_(RelocInfo::kNoPosition) {}
 
   virtual Statement* AsStatement()  { return this; }
   virtual ReturnStatement* AsReturnStatement() { return NULL; }
 
@@ skipping 20 matching lines @@
     // Evaluated for control flow (and side effects).
     kTest,
     // 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), def_(NULL), defined_vars_(NULL) {}
+  Expression()
+      : bitfields_(0),
+        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; }
 
   // True if the expression has no side effects and is safe to
   // evaluate out of order.
   virtual bool IsTrivial() { 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;
   }
 
+  // AST analysis results
+
+  // True if the expression rooted at this node can be compiled by the
+  // side-effect free compiler.
+  bool side_effect_free() { return SideEffectFreeField::decode(bitfields_); }
+  void set_side_effect_free(bool is_side_effect_free) {
+    bitfields_ &= ~SideEffectFreeField::mask();
+    bitfields_ |= SideEffectFreeField::encode(is_side_effect_free);
+  }
+
+  // Will ToInt32 (ECMA 262-3 9.5) or ToUint32 (ECMA 262-3 9.6)
+  // be applied to the value of this expression?
+  // If so, we may be able to optimize the calculation of the value.
+  bool to_int32() { return ToInt32Field::decode(bitfields_); }
+  void set_to_int32(bool to_int32) {
+    bitfields_ &= ~ToInt32Field::mask();
+    bitfields_ |= ToInt32Field::encode(to_int32);
+  }
+
+
  private:
+  uint32_t bitfields_;
   StaticType type_;
-  int num_;
+
   DefinitionInfo* def_;
   ZoneList<DefinitionInfo*>* defined_vars_;
+
+  // Using template BitField<type, start, size>.
+  class SideEffectFreeField : public BitField<bool, 0, 1> {};
+  class ToInt32Field : public BitField<bool, 1, 1> {};
 };
 
 
 /**
  * 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 696 matching lines @@
     return !is_this() && name().is_identical_to(n);
   }
 
   bool IsArguments() {
     Variable* variable = AsVariable();
     return (variable == NULL) ? false : variable->is_arguments();
   }
 
   Handle<String> name() const  { return name_; }
   Variable* var() const  { return var_; }
-  UseCount* var_uses()  { return &var_uses_; }
-  UseCount* obj_uses()  { return &obj_uses_; }
   bool is_this() const  { return is_this_; }
   bool inside_with() const  { return inside_with_; }
 
   // Bind this proxy to the variable var.
   void BindTo(Variable* var);
 
  protected:
   Handle<String> name_;
   Variable* var_;  // resolved variable, or NULL
   bool is_this_;
   bool inside_with_;
 
-  // VariableProxy usage info.
-  UseCount var_uses_;  // uses of the variable value
-  UseCount obj_uses_;  // uses of the object the variable points to
-
   VariableProxy(Handle<String> name, bool is_this, bool inside_with);
   explicit VariableProxy(bool is_this);
 
   friend class Scope;
 };
 
 
 class VariableProxySentinel: public VariableProxy {
  public:
   virtual bool IsValidLeftHandSide() { return !is_this(); }
@@ skipping 38 matching lines @@
     ASSERT(var != NULL);
   }
 
   virtual void Accept(AstVisitor* v);
 
   // Type testing & conversion
   virtual Slot* AsSlot() { return this; }
 
   virtual bool IsLeaf() { return true; }
 
+  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(); }
 
  private:
   Variable* var_;
   Type type_;
   int index_;
@@ skipping 814 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_