parser.cc.svn-base

Google浏览器V8内核代码

// 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
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#include "api.h"
#include "ast.h"
#include "bootstrapper.h"
#include "platform.h"
#include "runtime.h"
#include "parser.h"
#include "scopes.h"

namespace v8 { namespace internal {

class ParserFactory;
class ParserLog;
class TemporaryScope;
template <typename T> class ZoneListWrapper;


class Parser {
 public:
  Parser(Handle<Script> script, bool allow_natives_syntax,
         v8::Extension* extension, bool is_pre_parsing,
         ParserFactory* factory, ParserLog* log, ScriptDataImpl* pre_data);
  virtual ~Parser() { }

  // Pre-parse the program from the character stream; returns true on
  // success, false if a stack-overflow happened during parsing.
  bool PreParseProgram(unibrow::CharacterStream* stream);

  void ReportMessage(const char* message, Vector<const char*> args);
  virtual void ReportMessageAt(Scanner::Location loc,
                               const char* message,
                               Vector<const char*> args) = 0;


  // Returns NULL if parsing failed.
  FunctionLiteral* ParseProgram(Handle<String> source,
                                unibrow::CharacterStream* stream,
                                bool in_global_context);
  FunctionLiteral* ParseLazy(Handle<String> source,
                             Handle<String> name,
                             int start_position, bool is_expression);

 protected:

  enum Mode {
    PARSE_LAZILY,
    PARSE_EAGERLY
  };

  // Report syntax error
  void ReportUnexpectedToken(Token::Value token);

  Handle<Script> script_;
  Scanner scanner_;

  Scope* top_scope_;
  int with_nesting_level_;

  TemporaryScope* temp_scope_;
  Mode mode_;
  List<Node*>* target_stack_;  // for break, continue statements
  bool allow_natives_syntax_;
  v8::Extension* extension_;
  ParserFactory* factory_;
  ParserLog* log_;
  bool is_pre_parsing_;
  ScriptDataImpl* pre_data_;

  bool inside_with() const  { return with_nesting_level_ > 0; }
  ParserFactory* factory() const  { return factory_; }
  ParserLog* log() const { return log_; }
  Scanner& scanner()  { return scanner_; }
  Mode mode() const  { return mode_; }
  ScriptDataImpl* pre_data() const  { return pre_data_; }

  // All ParseXXX functions take as the last argument an *ok parameter
  // which is set to false if parsing failed; it is unchanged otherwise.
  // By making the 'exception handling' explicit, we are forced to check
  // for failure at the call sites.
  void* ParseSourceElements(ZoneListWrapper<Statement>* processor,
                            int end_token, bool* ok);
  Statement* ParseStatement(ZoneStringList* labels, bool* ok);
  Statement* ParseFunctionDeclaration(bool* ok);
  Statement* ParseNativeDeclaration(bool* ok);
  Block* ParseBlock(ZoneStringList* labels, bool* ok);
  Block* ParseVariableStatement(bool* ok);
  Block* ParseVariableDeclarations(bool accept_IN, Expression** var, bool* ok);
  Statement* ParseExpressionOrLabelledStatement(ZoneStringList* labels,
                                                bool* ok);
  IfStatement* ParseIfStatement(ZoneStringList* labels, bool* ok);
  Statement* ParseContinueStatement(bool* ok);
  Statement* ParseBreakStatement(ZoneStringList* labels, bool* ok);
  Statement* ParseReturnStatement(bool* ok);
  Block* WithHelper(Expression* obj, ZoneStringList* labels, bool* ok);
  Statement* ParseWithStatement(ZoneStringList* labels, bool* ok);
  CaseClause* ParseCaseClause(bool* default_seen_ptr, bool* ok);
  SwitchStatement* ParseSwitchStatement(ZoneStringList* labels, bool* ok);
  LoopStatement* ParseDoStatement(ZoneStringList* labels, bool* ok);
  LoopStatement* ParseWhileStatement(ZoneStringList* labels, bool* ok);
  Statement* ParseForStatement(ZoneStringList* labels, bool* ok);
  Statement* ParseThrowStatement(bool* ok);
  Expression* MakeCatchContext(Handle<String> id, VariableProxy* value);
  TryStatement* ParseTryStatement(bool* ok);
  DebuggerStatement* ParseDebuggerStatement(bool* ok);

  Expression* ParseExpression(bool accept_IN, bool* ok);
  Expression* ParseAssignmentExpression(bool accept_IN, bool* ok);
  Expression* ParseConditionalExpression(bool accept_IN, bool* ok);
  Expression* ParseBinaryExpression(int prec, bool accept_IN, bool* ok);
  Expression* ParseUnaryExpression(bool* ok);
  Expression* ParsePostfixExpression(bool* ok);
  Expression* ParseLeftHandSideExpression(bool* ok);
  Expression* ParseNewExpression(bool* ok);
  Expression* ParseMemberExpression(bool* ok);
  Expression* ParseMemberWithNewPrefixesExpression(List<int>* new_prefixes,
                                                   bool* ok);
  Expression* ParsePrimaryExpression(bool* ok);
  Expression* ParseArrayLiteral(bool* ok);
  Expression* ParseObjectLiteral(bool* ok);
  Expression* ParseRegExpLiteral(bool seen_equal, bool* ok);

  // Decide if a property should be the object boilerplate.
  bool IsBoilerplateProperty(ObjectLiteral::Property* property);
  // If the property is CONSTANT type, it returns the literal value,
  // otherwise, it return undefined literal as the placeholder
  // in the object literal boilerplate.
  Literal* GetBoilerplateValue(ObjectLiteral::Property* property);

  enum FunctionLiteralType {
    EXPRESSION,
    DECLARATION,
    NESTED
  };

  ZoneList<Expression*>* ParseArguments(bool* ok);
  FunctionLiteral* ParseFunctionLiteral(Handle<String> var_name,
                                        int function_token_position,
                                        FunctionLiteralType type,
                                        bool* ok);


  // Magical syntax support.
  Expression* ParseV8Intrinsic(bool* ok);

  INLINE(Token::Value peek()) { return scanner_.peek(); }
  INLINE(Token::Value Next()) { return scanner_.Next(); }
  INLINE(void Consume(Token::Value token));
  void Expect(Token::Value token, bool* ok);
  void ExpectSemicolon(bool* ok);

  // Get odd-ball literals.
  Literal* GetLiteralUndefined();
  Literal* GetLiteralTheHole();
  Literal* GetLiteralNumber(double value);

  Handle<String> ParseIdentifier(bool* ok);
  Handle<String> ParseIdentifierOrGetOrSet(bool* is_get,
                                           bool* is_set,
                                           bool* ok);

  // Parser support
  virtual VariableProxy* Declare(Handle<String> name, Variable::Mode mode,
                                 FunctionLiteral* fun,
                                 bool resolve,
                                 bool* ok) = 0;

  bool TargetStackContainsLabel(Handle<String> label);
  BreakableStatement* LookupBreakTarget(Handle<String> label, bool* ok);
  IterationStatement* LookupContinueTarget(Handle<String> label, bool* ok);

  void RegisterLabelUse(Label* label, int index);

  // Create a number literal.
  Literal* NewNumberLiteral(double value);

  // Generate AST node that throw a ReferenceError with the given type.
  Expression* NewThrowReferenceError(Handle<String> type);

  // Generate AST node that throw a SyntaxError with the given
  // type. The first argument may be null (in the handle sense) in
  // which case no arguments are passed to the constructor.
  Expression* NewThrowSyntaxError(Handle<String> type, Handle<Object> first);

  // Generate AST node that throw a TypeError with the given
  // type. Both arguments must be non-null (in the handle sense).
  Expression* NewThrowTypeError(Handle<String> type,
                                Handle<Object> first,
                                Handle<Object> second);

  // Generic AST generator for throwing errors from compiled code.
  Expression* NewThrowError(Handle<String> constructor,
                            Handle<String> type,
                            Vector< Handle<Object> > arguments);

  friend class Target;
  friend class TargetScope;
  friend class LexicalScope;
  friend class TemporaryScope;
};


// A temporary scope stores information during parsing, just like
// a plain scope.  However, temporary scopes are not kept around
// after parsing or referenced by syntax trees so they can be stack-
// allocated and hence used by the pre-parser.
class TemporaryScope BASE_EMBEDDED {
 public:
  explicit TemporaryScope(Parser* parser);
  ~TemporaryScope();

  int NextMaterializedLiteralIndex() {
    int next_index =
        materialized_literal_count_ + JSFunction::kLiteralsPrefixSize;
    materialized_literal_count_++;
    return next_index;
  }
  int materialized_literal_count() { return materialized_literal_count_; }

  void set_contains_array_literal() { contains_array_literal_ = true; }
  bool contains_array_literal() { return contains_array_literal_; }

  void AddProperty() { expected_property_count_++; }
  int expected_property_count() { return expected_property_count_; }
 private:
  // Captures the number of nodes that need materialization in the
  // function.  regexp literals, and boilerplate for object literals.
  int materialized_literal_count_;

  // Captures whether or not the function contains array literals.  If
  // the function contains array literals, we have to allocate space
  // for the array constructor in the literals array of the function.
  // This array constructor is used when creating the actual array
  // literals.
  bool contains_array_literal_;

  // Properties count estimation.
  int expected_property_count_;

  // Bookkeeping
  Parser* parser_;
  TemporaryScope* parent_;

  friend class Parser;
};


TemporaryScope::TemporaryScope(Parser* parser)
  : materialized_literal_count_(0),
    contains_array_literal_(false),
    expected_property_count_(0),
    parser_(parser),
    parent_(parser->temp_scope_) {
  parser->temp_scope_ = this;
}


TemporaryScope::~TemporaryScope() {
  parser_->temp_scope_ = parent_;
}


// A zone list wrapper lets code either access a access a zone list
// or appear to do so while actually ignoring all operations.
template <typename T>
class ZoneListWrapper {
 public:
  ZoneListWrapper() : list_(NULL) { }
  explicit ZoneListWrapper(int size) : list_(new ZoneList<T*>(size)) { }
  void Add(T* that) { if (list_) list_->Add(that); }
  int length() { return list_->length(); }
  ZoneList<T*>* elements() { return list_; }
  T* at(int index) { return list_->at(index); }
 private:
  ZoneList<T*>* list_;
};


// Allocation macro that should be used to allocate objects that must
// only be allocated in real parsing mode.  Note that in preparse mode
// not only is the syntax tree not created but the constructor
// arguments are not evaulated.
#define NEW(expr) (is_pre_parsing_ ? NULL : new expr)


class ParserFactory BASE_EMBEDDED {
 public:
  explicit ParserFactory(bool is_pre_parsing) :
      is_pre_parsing_(is_pre_parsing) { }

  virtual ~ParserFactory() { }

  virtual Scope* NewScope(Scope* parent, Scope::Type type, bool inside_with);

  virtual Handle<String> LookupSymbol(const char* string, int length) {
    return Handle<String>();
  }

  virtual Handle<String> EmptySymbol() {
    return Handle<String>();
  }

  virtual Expression* NewProperty(Expression* obj, Expression* key, int pos) {
    if (obj == VariableProxySentinel::this_proxy()) {
      return Property::this_property();
    } else {
      return ValidLeftHandSideSentinel::instance();
    }
  }

  virtual Expression* NewCall(Expression* expression,
                              ZoneList<Expression*>* arguments,
                              bool is_eval, int pos) {
    return Call::sentinel();
  }

  virtual Statement* EmptyStatement() {
    return NULL;
  }

  template <typename T> ZoneListWrapper<T> NewList(int size) {
    return is_pre_parsing_ ? ZoneListWrapper<T>() : ZoneListWrapper<T>(size);
  }

 private:
  bool is_pre_parsing_;
};


class ParserLog BASE_EMBEDDED {
 public:
  virtual ~ParserLog() { }

  // Records the occurrence of a function.  The returned object is
  // only guaranteed to be valid until the next function has been
  // logged.
  virtual FunctionEntry LogFunction(int start) { return FunctionEntry(); }

  virtual void LogError() { }
};


class AstBuildingParserFactory : public ParserFactory {
 public:
  AstBuildingParserFactory() : ParserFactory(false) { }

  virtual Scope* NewScope(Scope* parent, Scope::Type type, bool inside_with);

  virtual Handle<String> LookupSymbol(const char* string, int length) {
    return Factory::LookupSymbol(Vector<const char>(string, length));
  }