ast.h.svn-base

Google浏览器V8内核代码

  // Generate code to store into an expression evaluated as the left-hand
  // side of an assignment.  The code will expect the stored value on top of
  // the expression stack, and a reference containing the expression
  // immediately below that.
  virtual void GenerateStoreCode(MacroAssembler* masm,
                                 Scope* scope,
                                 Reference* ref,
                                 InitState init_state);
 private:
  Variable* var_;
  Type type_;
  int index_;
};


class Property: public Expression {
 public:
  Property(Expression* obj, Expression* key, int pos)
      : obj_(obj), key_(key), pos_(pos) { }

  virtual void Accept(Visitor* v);

  // Type testing & conversion
  virtual Property* AsProperty() { return this; }

  virtual bool IsValidLeftHandSide() { return true; }

  Expression* obj() const { return obj_; }
  Expression* key() const { return key_; }
  int position() const { return pos_; }

  // Returns a property singleton property access on 'this'.  Used
  // during preparsing.
  static Property* this_property() { return &this_property_; }

  // Generate code to store into an expression evaluated as the left-hand
  // side of an assignment.  The code will expect the stored value on top of
  // the expression stack, and a reference containing the expression
  // immediately below that.
  virtual void GenerateStoreCode(MacroAssembler* masm,
                                 Scope* scope,
                                 Reference* ref,
                                 InitState init_state);
 private:
  Expression* obj_;
  Expression* key_;
  int pos_;

  // Dummy property used during preparsing
  static Property this_property_;
};


class Call: public Expression {
 public:
  Call(Expression* expression,
       ZoneList<Expression*>* arguments,
       bool is_eval,
       int pos)
      : expression_(expression),
        arguments_(arguments),
        is_eval_(is_eval),
        pos_(pos) { }

  virtual void Accept(Visitor* v);

  // Type testing and conversion.
  virtual Call* AsCall() { return this; }

  Expression* expression() const { return expression_; }
  ZoneList<Expression*>* arguments() const { return arguments_; }
  bool is_eval()  { return is_eval_; }
  int position() { return pos_; }

  static Call* sentinel() { return &sentinel_; }

 private:
  Expression* expression_;
  ZoneList<Expression*>* arguments_;
  bool is_eval_;
  int pos_;

  static Call sentinel_;
};


class CallNew: public Call {
 public:
  CallNew(Expression* expression, ZoneList<Expression*>* arguments, int pos)
      : Call(expression, arguments, false, pos) { }

  virtual void Accept(Visitor* v);
};


// The CallRuntime class does not represent any official JavaScript
// language construct. Instead it is used to call a C or JS function
// with a set of arguments. This is used from the builtins that are
// implemented in JavaScript (see "v8natives.js").
class CallRuntime: public Expression {
 public:
  CallRuntime(Handle<String> name,
              Runtime::Function* function,
              ZoneList<Expression*>* arguments)
      : name_(name), function_(function), arguments_(arguments) { }

  virtual void Accept(Visitor* v);

  Handle<String> name() const { return name_; }
  Runtime::Function* function() const { return function_; }
  ZoneList<Expression*>* arguments() const { return arguments_; }

 private:
  Handle<String> name_;
  Runtime::Function* function_;
  ZoneList<Expression*>* arguments_;
};


class UnaryOperation: public Expression {
 public:
  UnaryOperation(Token::Value op, Expression* expression)
    : op_(op), expression_(expression) {
    ASSERT(Token::IsUnaryOp(op));
  }

  virtual void Accept(Visitor* v);

  // Type testing & conversion
  virtual UnaryOperation* AsUnaryOperation() { return this; }

  Token::Value op() const { return op_; }
  Expression* expression() const { return expression_; }

 private:
  Token::Value op_;
  Expression* expression_;
};


class BinaryOperation: public Expression {
 public:
  BinaryOperation(Token::Value op, Expression* left, Expression* right)
    : op_(op), left_(left), right_(right) {
    ASSERT(Token::IsBinaryOp(op));
  }

  virtual void Accept(Visitor* v);

  // Type testing & conversion
  virtual BinaryOperation* AsBinaryOperation() { return this; }

  // True iff the result can be safely overwritten (to avoid allocation).
  // False for operations that can return one of their operands.
  bool ResultOverwriteAllowed() {
    switch (op_) {
      case Token::COMMA:
      case Token::OR:
      case Token::AND:
        return false;
      case Token::BIT_OR:
      case Token::BIT_XOR:
      case Token::BIT_AND:
      case Token::SHL:
      case Token::SAR:
      case Token::SHR:
      case Token::ADD:
      case Token::SUB:
      case Token::MUL:
      case Token::DIV:
      case Token::MOD:
        return true;
      default:
        UNREACHABLE();
    }
    return false;
  }

  Token::Value op() const { return op_; }
  Expression* left() const { return left_; }
  Expression* right() const { return right_; }

 private:
  Token::Value op_;
  Expression* left_;
  Expression* right_;
};


class CountOperation: public Expression {
 public:
  CountOperation(bool is_prefix, Token::Value op, Expression* expression)
    : is_prefix_(is_prefix), op_(op), expression_(expression) {
    ASSERT(Token::IsCountOp(op));
  }

  virtual void Accept(Visitor* v);

  bool is_prefix() const { return is_prefix_; }
  bool is_postfix() const { return !is_prefix_; }
  Token::Value op() const { return op_; }
  Expression* expression() const { return expression_; }

  virtual void MarkAsStatement() { is_prefix_ = true; }

 private:
  bool is_prefix_;
  Token::Value op_;
  Expression* expression_;
};


class CompareOperation: public Expression {
 public:
  CompareOperation(Token::Value op, Expression* left, Expression* right)
    : op_(op), left_(left), right_(right) {
    ASSERT(Token::IsCompareOp(op));
  }

  virtual void Accept(Visitor* v);

  Token::Value op() const { return op_; }
  Expression* left() const { return left_; }
  Expression* right() const { return right_; }

 private:
  Token::Value op_;
  Expression* left_;
  Expression* right_;
};


class Conditional: public Expression {
 public:
  Conditional(Expression* condition,
              Expression* then_expression,
              Expression* else_expression)
      : condition_(condition),
        then_expression_(then_expression),
        else_expression_(else_expression) { }

  virtual void Accept(Visitor* v);

  Expression* condition() const { return condition_; }
  Expression* then_expression() const { return then_expression_; }
  Expression* else_expression() const { return else_expression_; }

 private:
  Expression* condition_;
  Expression* then_expression_;
  Expression* else_expression_;
};


class Assignment: public Expression {
 public:
  Assignment(Token::Value op, Expression* target, Expression* value, int pos)
    : op_(op), target_(target), value_(value), pos_(pos) {
    ASSERT(Token::IsAssignmentOp(op));
  }

  virtual void Accept(Visitor* v);
  virtual Assignment* AsAssignment() { return this; }

  Token::Value binary_op() const;

  Token::Value op() const { return op_; }
  Expression* target() const { return target_; }
  Expression* value() const { return value_; }
  int position() { return pos_; }

 private:
  Token::Value op_;
  Expression* target_;
  Expression* value_;
  int pos_;
};


class Throw: public Expression {
 public:
  Throw(Expression* exception, int pos)
      : exception_(exception), pos_(pos) {}

  virtual void Accept(Visitor* v);
  Expression* exception() const { return exception_; }
  int position() const { return pos_; }

 private:
  Expression* exception_;
  int pos_;
};


class FunctionLiteral: public Expression {
 public:
  FunctionLiteral(Handle<String> name,
                  Scope* scope,
                  ZoneList<Statement*>* body,
                  int materialized_literal_count,
                  bool contains_array_literal,
                  int expected_property_count,
                  int num_parameters,
                  int start_position,
                  int end_position,
                  bool is_expression)
      : name_(name),
        scope_(scope),
        body_(body),
        materialized_literal_count_(materialized_literal_count),
        contains_array_literal_(contains_array_literal),
        expected_property_count_(expected_property_count),
        num_parameters_(num_parameters),
        start_position_(start_position),
        end_position_(end_position),
        is_expression_(is_expression),
        function_token_position_(RelocInfo::kNoPosition) {
  }

  virtual void Accept(Visitor* v);

  // Type testing & conversion
  virtual FunctionLiteral* AsFunctionLiteral()  { return this; }

  Handle<String> name() const  { return name_; }
  Scope* scope() const  { return scope_; }
  ZoneList<Statement*>* body() const  { return body_; }
  void set_function_token_position(int pos) { function_token_position_ = pos; }
  int function_token_position() const { return function_token_position_; }
  int start_position() const { return start_position_; }
  int end_position() const { return end_position_; }
  bool is_expression() const { return is_expression_; }

  int materialized_literal_count() { return materialized_literal_count_; }
  bool contains_array_literal() { return contains_array_literal_; }
  int expected_property_count() { return expected_property_count_; }
  int num_parameters() { return num_parameters_; }

  bool AllowsLazyCompilation();

 private:
  Handle<String> name_;
  Scope* scope_;
  ZoneList<Statement*>* body_;
  int materialized_literal_count_;
  bool contains_array_literal_;
  int expected_property_count_;
  int num_parameters_;
  int start_position_;
  int end_position_;
  bool is_expression_;
  int function_token_position_;
};


class FunctionBoilerplateLiteral: public Expression {
 public:
  explicit FunctionBoilerplateLiteral(Handle<JSFunction> boilerplate)
      : boilerplate_(boilerplate) {
    ASSERT(boilerplate->IsBoilerplate());
  }

  Handle<JSFunction> boilerplate() const { return boilerplate_; }

  virtual void Accept(Visitor* v);

 private:
  Handle<JSFunction> boilerplate_;
};


class ThisFunction: public Expression {
 public:
  virtual void Accept(Visitor* v);
};


// ----------------------------------------------------------------------------
// Basic visitor
// - leaf node visitors are abstract.

class Visitor BASE_EMBEDDED {
 public:
  Visitor() : stack_overflow_(false) { }
  virtual ~Visitor() { }

  // Dispatch
  void Visit(Node* node) { node->Accept(this); }

  // Iteration
  virtual void VisitStatements(ZoneList<Statement*>* statements);
  virtual void VisitExpressions(ZoneList<Expression*>* expressions);

  // Stack overflow tracking support.
  bool HasStackOverflow() const { return stack_overflow_; }
  bool CheckStackOverflow() {
    if (stack_overflow_) return true;
    StackLimitCheck check;
    if (!check.HasOverflowed()) return false;
    return (stack_overflow_ = true);
  }

  // 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; }


  // Individual nodes
#define DEF_VISIT(type)                         \
  virtual void Visit##type(type* node) = 0;
  NODE_LIST(DEF_VISIT)
#undef DEF_VISIT

 private:
  bool stack_overflow_;
};


} }  // namespace v8::internal

#endif  // V8_AST_H_