Merge preparser Scanner with main JavaScript scanner.

Optimize scanning of keywords.

Review URL: http://codereview.chromium.org/5188009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5858 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/parser.cc

@@ -37,7 +37,6 @@
 #include "parser.h"
 #include "platform.h"
 #include "preparser.h"
-#include "prescanner.h"
 #include "runtime.h"
 #include "scopeinfo.h"
 #include "string-stream.h"
@@ -4637,12 +4636,15 @@ int ScriptDataImpl::ReadNumber(byte** source) {
 }
 
 
-static ScriptDataImpl* DoPreParse(UTF16Buffer* stream,
+// Create a Scanner for the preparser to use as input, and preparse the source.
+static ScriptDataImpl* DoPreParse(Handle<String> source,
+                                  unibrow::CharacterStream* stream,
                                   bool allow_lazy,
-                                  PartialParserRecorder* recorder) {
-  preparser::Scanner scanner;
-  scanner.Initialize(stream);
-  preparser::PreParser<preparser::Scanner, PartialParserRecorder> preparser;
+                                  PartialParserRecorder* recorder,
+                                  int literal_flags) {
+  V8JavaScriptScanner scanner;
+  scanner.Initialize(source, stream, literal_flags);
+  preparser::PreParser<JavaScriptScanner, PartialParserRecorder> preparser;
   if (!preparser.PreParseProgram(&scanner, recorder, allow_lazy)) {
     Top::StackOverflow();
     return NULL;
@@ -4655,44 +4657,11 @@ static ScriptDataImpl* DoPreParse(UTF16Buffer* stream,
 }
 
 
-// Create an UTF16Buffer for the preparser to use as input,
-// and preparse the source.
-static ScriptDataImpl* DoPreParse(Handle<String> source,
-                                  unibrow::CharacterStream* stream,
-                                  bool allow_lazy,
-                                  PartialParserRecorder* recorder) {
-  if (source.is_null()) {
-    CharacterStreamUTF16Buffer buffer;
-    int length = stream->Length();
-    buffer.Initialize(source, stream, 0, length);
-    return DoPreParse(&buffer, allow_lazy, recorder);
-  } else if (source->IsExternalAsciiString()) {
-    ExternalStringUTF16Buffer<ExternalAsciiString, char> buffer;
-    int length = source->length();
-    buffer.Initialize(Handle<ExternalAsciiString>::cast(source), 0, length);
-    return DoPreParse(&buffer, allow_lazy, recorder);
-  } else if (source->IsExternalTwoByteString()) {
-    ExternalStringUTF16Buffer<ExternalTwoByteString, uint16_t> buffer;
-    int length = source->length();
-    buffer.Initialize(Handle<ExternalTwoByteString>::cast(source), 0, length);
-    return DoPreParse(&buffer, allow_lazy, recorder);
-  } else {
-    CharacterStreamUTF16Buffer buffer;
-    SafeStringInputBuffer input;
-    input.Reset(0, source.location());
-    int length = source->length();
-    buffer.Initialize(source, &input, 0, length);
-    return DoPreParse(&buffer, allow_lazy, recorder);
-  }
-}
-
-
 // Preparse, but only collect data that is immediately useful,
 // even if the preparser data is only used once.
 ScriptDataImpl* ParserApi::PartialPreParse(Handle<String> source,
                                            unibrow::CharacterStream* stream,
                                            v8::Extension* extension) {
-  Handle<Script> no_script;
   bool allow_lazy = FLAG_lazy && (extension == NULL);
   if (!allow_lazy) {
     // Partial preparsing is only about lazily compiled functions.
@@ -4701,7 +4670,8 @@ ScriptDataImpl* ParserApi::PartialPreParse(Handle<String> source,
   }
   PartialParserRecorder recorder;
 
-  return DoPreParse(source, stream, allow_lazy, &recorder);
+  return DoPreParse(source, stream, allow_lazy, &recorder,
+                    JavaScriptScanner::kNoLiterals);
 }
 
 
@@ -4711,7 +4681,10 @@ ScriptDataImpl* ParserApi::PreParse(Handle<String> source,
   Handle<Script> no_script;
   bool allow_lazy = FLAG_lazy && (extension == NULL);
   CompleteParserRecorder recorder;
-  return DoPreParse(source, stream, allow_lazy, &recorder);
+  int kPreParseLiteralsFlags =
+      JavaScriptScanner::kLiteralString | JavaScriptScanner::kLiteralIdentifier;
+  return DoPreParse(source, stream, allow_lazy,
+                    &recorder, kPreParseLiteralsFlags);
 }
 
 

src/scanner-base.cc

@@ -480,7 +480,7 @@ void JavaScriptScanner::Scan() {
 
       default:
         if (ScannerConstants::kIsIdentifierStart.get(c0_)) {
-          token = ScanIdentifier();
+          token = ScanIdentifierOrKeyword();
         } else if (IsDecimalDigit(c0_)) {
           token = ScanNumber(false);
         } else if (SkipWhiteSpace()) {
@@ -559,7 +559,7 @@ Token::Value JavaScriptScanner::ScanString() {
   uc32 quote = c0_;
   Advance();  // consume quote
 
-  LiteralScope literal(this);
+  LiteralScope literal(this, kLiteralString);
   while (c0_ != quote && c0_ >= 0
          && !ScannerConstants::kIsLineTerminator.get(c0_)) {
     uc32 c = c0_;
@@ -590,7 +590,7 @@ Token::Value JavaScriptScanner::ScanNumber(bool seen_period) {
 
   enum { DECIMAL, HEX, OCTAL } kind = DECIMAL;
 
-  LiteralScope literal(this);
+  LiteralScope literal(this, kLiteralNumber);
   if (seen_period) {
     // we have already seen a decimal point of the float
     AddLiteralChar('.');
@@ -677,25 +677,44 @@ uc32 JavaScriptScanner::ScanIdentifierUnicodeEscape() {
 }
 
 
-Token::Value JavaScriptScanner::ScanIdentifier() {
+Token::Value JavaScriptScanner::ScanIdentifierOrKeyword() {
   ASSERT(ScannerConstants::kIsIdentifierStart.get(c0_));
-
-  LiteralScope literal(this);
+  LiteralScope literal(this, kLiteralIdentifier);
   KeywordMatcher keyword_match;
-
   // Scan identifier start character.
   if (c0_ == '\\') {
     uc32 c = ScanIdentifierUnicodeEscape();
     // Only allow legal identifier start characters.
     if (!ScannerConstants::kIsIdentifierStart.get(c)) return Token::ILLEGAL;
     AddLiteralChar(c);
-    keyword_match.Fail();
-  } else {
-    AddLiteralChar(c0_);
-    keyword_match.AddChar(c0_);
-    Advance();
+    return ScanIdentifierSuffix(&literal);
+  }
+
+  uc32 first_char = c0_;
+  Advance();
+  AddLiteralChar(first_char);
+  if (!keyword_match.AddChar(first_char)) {
+    return ScanIdentifierSuffix(&literal);
+  }
+
+  // Scan the rest of the identifier characters.
+  while (ScannerConstants::kIsIdentifierPart.get(c0_)) {
+    if (c0_ != '\\') {
+      uc32 next_char = c0_;
+      Advance();
+      AddLiteralChar(next_char);
+      if (keyword_match.AddChar(next_char)) continue;
+    }
+    // Fallthrough if no loner able to complete keyword.
+    return ScanIdentifierSuffix(&literal);
   }
+  literal.Complete();
+
+  return keyword_match.token();
+}
+
 
+Token::Value JavaScriptScanner::ScanIdentifierSuffix(LiteralScope* literal) {
   // Scan the rest of the identifier characters.
   while (ScannerConstants::kIsIdentifierPart.get(c0_)) {
     if (c0_ == '\\') {
@@ -703,20 +722,17 @@ Token::Value JavaScriptScanner::ScanIdentifier() {
       // Only allow legal identifier part characters.
       if (!ScannerConstants::kIsIdentifierPart.get(c)) return Token::ILLEGAL;
       AddLiteralChar(c);
-      keyword_match.Fail();
     } else {
       AddLiteralChar(c0_);
-      keyword_match.AddChar(c0_);
       Advance();
     }
   }
-  literal.Complete();
+  literal->Complete();
 
-  return keyword_match.token();
+  return Token::IDENTIFIER;
 }
 
 
-
 bool JavaScriptScanner::ScanRegExpPattern(bool seen_equal) {
   // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags
   bool in_character_class = false;
@@ -729,7 +745,7 @@ bool JavaScriptScanner::ScanRegExpPattern(bool seen_equal) {
   // Scan regular expression body: According to ECMA-262, 3rd, 7.8.5,
   // the scanner should pass uninterpreted bodies to the RegExp
   // constructor.
-  LiteralScope literal(this);
+  LiteralScope literal(this, kLiteralRegExp);
   if (seen_equal)
     AddLiteralChar('=');
 
@@ -752,9 +768,10 @@ bool JavaScriptScanner::ScanRegExpPattern(bool seen_equal) {
   return true;
 }
 
+
 bool JavaScriptScanner::ScanRegExpFlags() {
   // Scan regular expression flags.
-  LiteralScope literal(this);
+  LiteralScope literal(this, kLiteralRegExpFlags);
   while (ScannerConstants::kIsIdentifierPart.get(c0_)) {
     if (c0_ == '\\') {
       uc32 c = ScanIdentifierUnicodeEscape();
@@ -868,9 +885,7 @@ void KeywordMatcher::Step(unibrow::uchar input) {
       break;
     case IN:
       token_ = Token::IDENTIFIER;
-      if (MatchKeywordStart(input, "instanceof", 2, Token::INSTANCEOF)) {
-        return;
-      }
+      if (MatchKeywordStart(input, "instanceof", 2, Token::INSTANCEOF)) return;
       break;
     case N:
       if (MatchKeywordStart(input, "native", 1, Token::NATIVE)) return;

src/scanner-base.h

@@ -327,6 +327,42 @@ class Scanner {
 
 class JavaScriptScanner : public Scanner {
  public:
+
+  // Bit vector representing set of types of literals.
+  enum LiteralType {
+    kNoLiterals = 0,
+    kLiteralNumber = 1,
+    kLiteralIdentifier = 2,
+    kLiteralString = 4,
+    kLiteralRegExp = 8,
+    kLiteralRegExpFlags = 16,
+    kAllLiterals = 31
+  };
+
+  // A LiteralScope that disables recording of some types of JavaScript
+  // literals. If the scanner is configured to not record the specific
+  // type of literal, the scope will not call StartLiteral.
+  class LiteralScope {
+   public:
+    LiteralScope(JavaScriptScanner* self, LiteralType type)
+        : scanner_(self), complete_(false) {
+      if (scanner_->RecordsLiteral(type)) {
+        scanner_->StartLiteral();
+      }
+    }
+     ~LiteralScope() {
+       if (!complete_) scanner_->DropLiteral();
+     }
+    void Complete() {
+      scanner_->TerminateLiteral();
+      complete_ = true;
+    }
+
+   private:
+    JavaScriptScanner* scanner_;
+    bool complete_;
+  };
+
   JavaScriptScanner();
 
   // Returns the next token.
@@ -354,6 +390,11 @@ class JavaScriptScanner : public Scanner {
   // tokens, which is what it is used for.
   void SeekForward(int pos);
 
+  // Whether this scanner records the given literal type or not.
+  bool RecordsLiteral(LiteralType type) {
+    return (literal_flags_ & type) != 0;
+  }
+
  protected:
   bool SkipWhiteSpace();
   Token::Value SkipSingleLineComment();
@@ -364,7 +405,8 @@ class JavaScriptScanner : public Scanner {
 
   void ScanDecimalDigits();
   Token::Value ScanNumber(bool seen_period);
-  Token::Value ScanIdentifier();
+  Token::Value ScanIdentifierOrKeyword();
+  Token::Value ScanIdentifierSuffix(LiteralScope* literal);
 
   void ScanEscape();
   Token::Value ScanString();
@@ -376,6 +418,7 @@ class JavaScriptScanner : public Scanner {
   // If the escape sequence cannot be decoded the result is kBadChar.
   uc32 ScanIdentifierUnicodeEscape();
 
+  int literal_flags_;
   bool has_line_terminator_before_next_;
 };
 
@@ -404,10 +447,11 @@ class KeywordMatcher {
 
   Token::Value token() { return token_; }
 
-  inline void AddChar(unibrow::uchar input) {
+  inline bool AddChar(unibrow::uchar input) {
     if (state_ != UNMATCHABLE) {
       Step(input);
     }
+    return state_ != UNMATCHABLE;
   }
 
   void Fail() {
@@ -458,23 +502,23 @@ class KeywordMatcher {
                                 const char* keyword,
                                 int position,
                                 Token::Value token_if_match) {
-    if (input == static_cast<unibrow::uchar>(keyword[position])) {
-      state_ = KEYWORD_PREFIX;
-      this->keyword_ = keyword;
-      this->counter_ = position + 1;
-      this->keyword_token_ = token_if_match;
-      return true;
+    if (input != static_cast<unibrow::uchar>(keyword[position])) {
+      return false;
     }
-    return false;
+    state_ = KEYWORD_PREFIX;
+    this->keyword_ = keyword;
+    this->counter_ = position + 1;
+    this->keyword_token_ = token_if_match;
+    return true;
   }
 
   // If input equals match character, transition to new state and return true.
   inline bool MatchState(unibrow::uchar input, char match, State new_state) {
-    if (input == static_cast<unibrow::uchar>(match)) {
-      state_ = new_state;
-      return true;
+    if (input != static_cast<unibrow::uchar>(match)) {
+      return false;
     }
-    return false;
+    state_ = new_state;
+    return true;
   }
 
   inline bool MatchKeyword(unibrow::uchar input,

src/scanner.cc

@@ -118,8 +118,12 @@ void Scanner::LiteralScope::Complete() {
 // ----------------------------------------------------------------------------
 // V8JavaScriptScanner
 
-void V8JavaScriptScanner::Initialize(Handle<String> source) {
+void V8JavaScriptScanner::Initialize(Handle<String> source,
+                                     int literal_flags) {
   source_ = stream_initializer_.Init(source, NULL, 0, source->length());
+  // Need to capture identifiers in order to recognize "get" and "set"
+  // in object literals.
+  literal_flags_ = literal_flags | kLiteralIdentifier;
   Init();
   // Skip initial whitespace allowing HTML comment ends just like
   // after a newline and scan first token.
@@ -130,9 +134,11 @@ void V8JavaScriptScanner::Initialize(Handle<String> source) {
 
 
 void V8JavaScriptScanner::Initialize(Handle<String> source,
-                                     unibrow::CharacterStream* stream) {
+                                     unibrow::CharacterStream* stream,
+                                     int literal_flags) {
   source_ = stream_initializer_.Init(source, stream,
                                      0, UTF16Buffer::kNoEndPosition);
+  literal_flags_ = literal_flags | kLiteralIdentifier;
   Init();
   // Skip initial whitespace allowing HTML comment ends just like
   // after a newline and scan first token.
@@ -144,9 +150,11 @@ void V8JavaScriptScanner::Initialize(Handle<String> source,
 
 void V8JavaScriptScanner::Initialize(Handle<String> source,
                                      int start_position,
-                                     int end_position) {
+                                     int end_position,
+                                     int literal_flags) {
   source_ = stream_initializer_.Init(source, NULL,
                                      start_position, end_position);
+  literal_flags_ = literal_flags | kLiteralIdentifier;
   Init();
   // Skip initial whitespace allowing HTML comment ends just like
   // after a newline and scan first token.

src/scanner.h

@@ -108,11 +108,13 @@ class V8JavaScriptScanner : public JavaScriptScanner {
   Token::Value NextCheckStack();
 
   // Initialize the Scanner to scan source.
-  void Initialize(Handle<String> source);
+  void Initialize(Handle<String> source, int literal_flags = kAllLiterals);
   void Initialize(Handle<String> source,
-                  unibrow::CharacterStream* stream);
+                  unibrow::CharacterStream* stream,
+                  int literal_flags = kAllLiterals);
   void Initialize(Handle<String> source,
-                  int start_position, int end_position);
+                  int start_position, int end_position,
+                  int literal_flags = kAllLiterals);
 
  protected:
   StreamInitializer stream_initializer_;