parser.cc.svn-base

Google浏览器V8内核代码

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

  virtual Expression* NewProperty(Expression* obj, Expression* key, int pos) {
    return new Property(obj, key, pos);
  }

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

  virtual Statement* EmptyStatement() {
    // Use a statically allocated empty statement singleton to avoid
    // allocating lots and lots of empty statements.
    static v8::internal::EmptyStatement empty;
    return &empty;
  }
};


class ParserRecorder: public ParserLog {
 public:
  ParserRecorder();
  virtual FunctionEntry LogFunction(int start);
  virtual void LogError() { }
  virtual void LogMessage(Scanner::Location loc,
                          const char* message,
                          Vector<const char*> args);
  void WriteString(Vector<const char> str);
  static const char* ReadString(unsigned* start, int* chars);
  List<unsigned>* store() { return &store_; }
 private:
  bool has_error_;
  List<unsigned> store_;
};


FunctionEntry ScriptDataImpl::GetFunctionEnd(int start) {
  if (nth(last_entry_).start_pos() > start) {
    // If the last entry we looked up is higher than what we're
    // looking for then it's useless and we reset it.
    last_entry_ = 0;
  }
  for (int i = last_entry_; i < EntryCount(); i++) {
    FunctionEntry entry = nth(i);
    if (entry.start_pos() == start) {
      last_entry_ = i;
      return entry;
    }
  }
  return FunctionEntry();
}


bool ScriptDataImpl::SanityCheck() {
  if (store_.length() < static_cast<int>(ScriptDataImpl::kHeaderSize))
    return false;
  if (magic() != ScriptDataImpl::kMagicNumber)
    return false;
  if (version() != ScriptDataImpl::kCurrentVersion)
    return false;
  return true;
}


int ScriptDataImpl::EntryCount() {
  return (store_.length() - kHeaderSize) / FunctionEntry::kSize;
}


FunctionEntry ScriptDataImpl::nth(int n) {
  int offset = kHeaderSize + n * FunctionEntry::kSize;
  return FunctionEntry(Vector<unsigned>(store_.start() + offset,
                                        FunctionEntry::kSize));
}


ParserRecorder::ParserRecorder()
  : has_error_(false), store_(4) {
  Vector<unsigned> preamble = store()->AddBlock(0, ScriptDataImpl::kHeaderSize);
  preamble[ScriptDataImpl::kMagicOffset] = ScriptDataImpl::kMagicNumber;
  preamble[ScriptDataImpl::kVersionOffset] = ScriptDataImpl::kCurrentVersion;
  preamble[ScriptDataImpl::kHasErrorOffset] = false;
}


void ParserRecorder::WriteString(Vector<const char> str) {
  store()->Add(str.length());
  for (int i = 0; i < str.length(); i++)
    store()->Add(str[i]);
}


const char* ParserRecorder::ReadString(unsigned* start, int* chars) {
  int length = start[0];
  char* result = NewArray<char>(length + 1);
  for (int i = 0; i < length; i++)
    result[i] = start[i + 1];
  result[length] = '\0';
  if (chars != NULL) *chars = length;
  return result;
}


void ParserRecorder::LogMessage(Scanner::Location loc, const char* message,
                                Vector<const char*> args) {
  if (has_error_) return;
  store()->Rewind(ScriptDataImpl::kHeaderSize);
  store()->at(ScriptDataImpl::kHasErrorOffset) = true;
  store()->Add(loc.beg_pos);
  store()->Add(loc.end_pos);
  store()->Add(args.length());
  WriteString(CStrVector(message));
  for (int i = 0; i < args.length(); i++)
    WriteString(CStrVector(args[i]));
}


Scanner::Location ScriptDataImpl::MessageLocation() {
  int beg_pos = Read(0);
  int end_pos = Read(1);
  return Scanner::Location(beg_pos, end_pos);
}


const char* ScriptDataImpl::BuildMessage() {
  unsigned* start = ReadAddress(3);
  return ParserRecorder::ReadString(start, NULL);
}


Vector<const char*> ScriptDataImpl::BuildArgs() {
  int arg_count = Read(2);
  const char** array = NewArray<const char*>(arg_count);
  int pos = ScriptDataImpl::kHeaderSize + Read(3);
  for (int i = 0; i < arg_count; i++) {
    int count = 0;
    array[i] = ParserRecorder::ReadString(ReadAddress(pos), &count);
    pos += count + 1;
  }
  return Vector<const char*>(array, arg_count);
}


unsigned ScriptDataImpl::Read(int position) {
  return store_[ScriptDataImpl::kHeaderSize + position];
}


unsigned* ScriptDataImpl::ReadAddress(int position) {
  return &store_[ScriptDataImpl::kHeaderSize + position];
}


FunctionEntry ParserRecorder::LogFunction(int start) {
  if (has_error_) return FunctionEntry();
  FunctionEntry result(store()->AddBlock(0, FunctionEntry::kSize));
  result.set_start_pos(start);
  return result;
}


class AstBuildingParser : public Parser {
 public:
  AstBuildingParser(Handle<Script> script, bool allow_natives_syntax,
                    v8::Extension* extension, ScriptDataImpl* pre_data)
      : Parser(script, allow_natives_syntax, extension, false,
               factory(), log(), pre_data) { }
  virtual void ReportMessageAt(Scanner::Location loc, const char* message,
                               Vector<const char*> args);
  virtual VariableProxy* Declare(Handle<String> name, Variable::Mode mode,
                                 FunctionLiteral* fun, bool resolve, bool* ok);
  AstBuildingParserFactory* factory() { return &factory_; }
  ParserLog* log() { return &log_; }

 private:
  ParserLog log_;
  AstBuildingParserFactory factory_;
};


class PreParser : public Parser {
 public:
  PreParser(Handle<Script> script, bool allow_natives_syntax,
            v8::Extension* extension)
      : Parser(script, allow_natives_syntax, extension, true,
               factory(), recorder(), NULL)
      , factory_(true) { }
  virtual void ReportMessageAt(Scanner::Location loc, const char* message,
                               Vector<const char*> args);
  virtual VariableProxy* Declare(Handle<String> name, Variable::Mode mode,
                                 FunctionLiteral* fun, bool resolve, bool* ok);
  ParserFactory* factory() { return &factory_; }
  ParserRecorder* recorder() { return &recorder_; }

 private:
  ParserRecorder recorder_;
  ParserFactory factory_;
};


Scope* AstBuildingParserFactory::NewScope(Scope* parent, Scope::Type type,
                                          bool inside_with) {
  Scope* result = new Scope(parent, type);
  result->Initialize(inside_with);
  return result;
}


Scope* ParserFactory::NewScope(Scope* parent, Scope::Type type,
                               bool inside_with) {
  ASSERT(parent != NULL);
  parent->type_ = type;
  return parent;
}


VariableProxy* PreParser::Declare(Handle<String> name, Variable::Mode mode,
                                  FunctionLiteral* fun, bool resolve,
                                  bool* ok) {
  return NULL;
}



// ----------------------------------------------------------------------------
// Target is a support class to facilitate manipulation of the
// Parser's target_stack_ (the stack of potential 'break' and
// 'continue' statement targets). Upon construction, a new target is
// added; it is removed upon destruction.

class Target BASE_EMBEDDED {
 public:
  Target(Parser* parser, Node* node) : parser_(parser) {
    parser_->target_stack_->Add(node);
  }

  ~Target() {
    parser_->target_stack_->RemoveLast();
  }

 private:
  Parser* parser_;
};


class TargetScope BASE_EMBEDDED {
 public:
  explicit TargetScope(Parser* parser)
      : parser_(parser), previous_(parser->target_stack_), stack_(0) {
    parser_->target_stack_ = &stack_;
  }

  ~TargetScope() {
    ASSERT(stack_.is_empty());
    parser_->target_stack_ = previous_;
  }

 private:
  Parser* parser_;
  List<Node*>* previous_;
  List<Node*> stack_;
};


// ----------------------------------------------------------------------------
// LexicalScope is a support class to facilitate manipulation of the
// Parser's scope stack. The constructor sets the parser's top scope
// to the incoming scope, and the destructor resets it.

class LexicalScope BASE_EMBEDDED {
 public:
  LexicalScope(Parser* parser, Scope* scope)
    : parser_(parser),
      prev_scope_(parser->top_scope_),
      prev_level_(parser->with_nesting_level_) {
    parser_->top_scope_ = scope;
    parser_->with_nesting_level_ = 0;
  }

  ~LexicalScope() {
    parser_->top_scope_ = prev_scope_;
    parser_->with_nesting_level_ = prev_level_;
  }

 private:
  Parser* parser_;
  Scope* prev_scope_;
  int prev_level_;
};


// ----------------------------------------------------------------------------
// The CHECK_OK macro is a convenient macro to enforce error
// handling for functions that may fail (by returning !*ok).
//
// CAUTION: This macro appends extra statements after a call,
// thus it must never be used where only a single statement
// is correct (e.g. an if statement branch w/o braces)!

#define CHECK_OK  ok);   \
  if (!*ok) return NULL; \
  ((void)0
#define DUMMY )  // to make indentation work
#undef DUMMY


// ----------------------------------------------------------------------------
// Implementation of Parser

Parser::Parser(Handle<Script> script,
               bool allow_natives_syntax,
               v8::Extension* extension,
               bool is_pre_parsing,
               ParserFactory* factory,
               ParserLog* log,
               ScriptDataImpl* pre_data)
    : script_(script),
      scanner_(is_pre_parsing),
      top_scope_(NULL),
      with_nesting_level_(0),
      temp_scope_(NULL),
      target_stack_(NULL),
      allow_natives_syntax_(allow_natives_syntax),
      extension_(extension),
      factory_(factory),
      log_(log),
      is_pre_parsing_(is_pre_parsing),
      pre_data_(pre_data) {
}


bool Parser::PreParseProgram(unibrow::CharacterStream* stream) {
  StatsRateScope timer(&Counters::pre_parse);
  StackGuard guard;
  AssertNoZoneAllocation assert_no_zone_allocation;
  AssertNoAllocation assert_no_allocation;
  NoHandleAllocation no_handle_allocation;
  scanner_.Init(Handle<String>(), stream, 0);
  ASSERT(target_stack_ == NULL);
  mode_ = PARSE_EAGERLY;
  DummyScope top_scope;
  LexicalScope scope(this, &top_scope);
  TemporaryScope temp_scope(this);
  ZoneListWrapper<Statement> processor;
  bool ok = true;
  ParseSourceElements(&processor, Token::EOS, &ok);
  return !scanner().stack_overflow();
}


FunctionLiteral* Parser::ParseProgram(Handle<String> source,
                                      unibrow::CharacterStream* stream,
                                      bool in_global_context) {
  ZoneScope zone_scope(DONT_DELETE_ON_EXIT);

  StatsRateScope timer(&Counters::parse);
  Counters::total_parse_size.Increment(source->length());

  // Initialize parser state.
  source->TryFlatten();
  scanner_.Init(source, stream, 0);
  ASSERT(target_stack_ == NULL);

  // Compute the parsing mode.
  mode_ = FLAG_lazy ? PARSE_LAZILY : PARSE_EAGERLY;
  if (allow_natives_syntax_ || extension_ != NULL) mode_ = PARSE_EAGERLY;

  Scope::Type type =
    in_global_context
      ? Scope::GLOBAL_SCOPE
      : Scope::EVAL_SCOPE;
  Handle<String> no_name = factory()->EmptySymbol();

  FunctionLiteral* result = NULL;
  { Scope* scope = factory()->NewScope(top_scope_, type, inside_with());