JavaScriptCore/parser/Lexer.cpp
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/parser/Lexer.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,1168 @@
+/*
+ *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
+ *  Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All Rights Reserved.
+ *  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
+ *  Copyright (C) 2010 Zoltan Herczeg (zherczeg@inf.u-szeged.hu)
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Library General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Library General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Library General Public License
+ *  along with this library; see the file COPYING.LIB.  If not, write to
+ *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "config.h"
+#include "Lexer.h"
+
+#include "JSFunction.h"
+
+#include "JSGlobalObjectFunctions.h"
+#include "Identifier.h"
+#include "NodeInfo.h"
+#include "Nodes.h"
+#include "dtoa.h"
+#include <ctype.h>
+#include <limits.h>
+#include <string.h>
+#include <wtf/Assertions.h>
+
+using namespace WTF;
+using namespace Unicode;
+
+#include "JSParser.h"
+#include "Lookup.h"
+#include "Lexer.lut.h"
+
+namespace JSC {
+
+
+enum CharacterType {
+    // Types for the main switch
+
+    // The first three types are fixed, and also used for identifying
+    // ASCII alpha and alphanumeric characters (see isIdentStart and isIdentPart).
+    CharacterIdentifierStart,
+    CharacterZero,
+    CharacterNumber,
+
+    CharacterInvalid,
+    CharacterLineTerminator,
+    CharacterExclamationMark,
+    CharacterOpenParen,
+    CharacterCloseParen,
+    CharacterOpenBracket,
+    CharacterCloseBracket,
+    CharacterComma,
+    CharacterColon,
+    CharacterQuestion,
+    CharacterTilde,
+    CharacterQuote,
+    CharacterDot,
+    CharacterSlash,
+    CharacterBackSlash,
+    CharacterSemicolon,
+    CharacterOpenBrace,
+    CharacterCloseBrace,
+
+    CharacterAdd,
+    CharacterSub,
+    CharacterMultiply,
+    CharacterModulo,
+    CharacterAnd,
+    CharacterXor,
+    CharacterOr,
+    CharacterLess,
+    CharacterGreater,
+    CharacterEqual,
+
+    // Other types (only one so far)
+    CharacterWhiteSpace,
+};
+
+// 128 ASCII codes
+static const unsigned short typesOfASCIICharacters[128] = {
+/*   0 - Null               */ CharacterInvalid,
+/*   1 - Start of Heading   */ CharacterInvalid,
+/*   2 - Start of Text      */ CharacterInvalid,
+/*   3 - End of Text        */ CharacterInvalid,
+/*   4 - End of Transm.     */ CharacterInvalid,
+/*   5 - Enquiry            */ CharacterInvalid,
+/*   6 - Acknowledgment     */ CharacterInvalid,
+/*   7 - Bell               */ CharacterInvalid,
+/*   8 - Back Space         */ CharacterInvalid,
+/*   9 - Horizontal Tab     */ CharacterWhiteSpace,
+/*  10 - Line Feed          */ CharacterLineTerminator,
+/*  11 - Vertical Tab       */ CharacterWhiteSpace,
+/*  12 - Form Feed          */ CharacterWhiteSpace,
+/*  13 - Carriage Return    */ CharacterLineTerminator,
+/*  14 - Shift Out          */ CharacterInvalid,
+/*  15 - Shift In           */ CharacterInvalid,
+/*  16 - Data Line Escape   */ CharacterInvalid,
+/*  17 - Device Control 1   */ CharacterInvalid,
+/*  18 - Device Control 2   */ CharacterInvalid,
+/*  19 - Device Control 3   */ CharacterInvalid,
+/*  20 - Device Control 4   */ CharacterInvalid,
+/*  21 - Negative Ack.      */ CharacterInvalid,
+/*  22 - Synchronous Idle   */ CharacterInvalid,
+/*  23 - End of Transmit    */ CharacterInvalid,
+/*  24 - Cancel             */ CharacterInvalid,
+/*  25 - End of Medium      */ CharacterInvalid,
+/*  26 - Substitute         */ CharacterInvalid,
+/*  27 - Escape             */ CharacterInvalid,
+/*  28 - File Separator     */ CharacterInvalid,
+/*  29 - Group Separator    */ CharacterInvalid,
+/*  30 - Record Separator   */ CharacterInvalid,
+/*  31 - Unit Separator     */ CharacterInvalid,
+/*  32 - Space              */ CharacterWhiteSpace,
+/*  33 - !                  */ CharacterExclamationMark,
+/*  34 - "                  */ CharacterQuote,
+/*  35 - #                  */ CharacterInvalid,
+/*  36 - $                  */ CharacterIdentifierStart,
+/*  37 - %                  */ CharacterModulo,
+/*  38 - &                  */ CharacterAnd,
+/*  39 - '                  */ CharacterQuote,
+/*  40 - (                  */ CharacterOpenParen,
+/*  41 - )                  */ CharacterCloseParen,
+/*  42 - *                  */ CharacterMultiply,
+/*  43 - +                  */ CharacterAdd,
+/*  44 - ,                  */ CharacterComma,
+/*  45 - -                  */ CharacterSub,
+/*  46 - .                  */ CharacterDot,
+/*  47 - /                  */ CharacterSlash,
+/*  48 - 0                  */ CharacterZero,
+/*  49 - 1                  */ CharacterNumber,
+/*  50 - 2                  */ CharacterNumber,
+/*  51 - 3                  */ CharacterNumber,
+/*  52 - 4                  */ CharacterNumber,
+/*  53 - 5                  */ CharacterNumber,
+/*  54 - 6                  */ CharacterNumber,
+/*  55 - 7                  */ CharacterNumber,
+/*  56 - 8                  */ CharacterNumber,
+/*  57 - 9                  */ CharacterNumber,
+/*  58 - :                  */ CharacterColon,
+/*  59 - ;                  */ CharacterSemicolon,
+/*  60 - <                  */ CharacterLess,
+/*  61 - =                  */ CharacterEqual,
+/*  62 - >                  */ CharacterGreater,
+/*  63 - ?                  */ CharacterQuestion,
+/*  64 - @                  */ CharacterInvalid,
+/*  65 - A                  */ CharacterIdentifierStart,
+/*  66 - B                  */ CharacterIdentifierStart,
+/*  67 - C                  */ CharacterIdentifierStart,
+/*  68 - D                  */ CharacterIdentifierStart,
+/*  69 - E                  */ CharacterIdentifierStart,
+/*  70 - F                  */ CharacterIdentifierStart,
+/*  71 - G                  */ CharacterIdentifierStart,
+/*  72 - H                  */ CharacterIdentifierStart,
+/*  73 - I                  */ CharacterIdentifierStart,
+/*  74 - J                  */ CharacterIdentifierStart,
+/*  75 - K                  */ CharacterIdentifierStart,
+/*  76 - L                  */ CharacterIdentifierStart,
+/*  77 - M                  */ CharacterIdentifierStart,
+/*  78 - N                  */ CharacterIdentifierStart,
+/*  79 - O                  */ CharacterIdentifierStart,
+/*  80 - P                  */ CharacterIdentifierStart,
+/*  81 - Q                  */ CharacterIdentifierStart,
+/*  82 - R                  */ CharacterIdentifierStart,
+/*  83 - S                  */ CharacterIdentifierStart,
+/*  84 - T                  */ CharacterIdentifierStart,
+/*  85 - U                  */ CharacterIdentifierStart,
+/*  86 - V                  */ CharacterIdentifierStart,
+/*  87 - W                  */ CharacterIdentifierStart,
+/*  88 - X                  */ CharacterIdentifierStart,
+/*  89 - Y                  */ CharacterIdentifierStart,
+/*  90 - Z                  */ CharacterIdentifierStart,
+/*  91 - [                  */ CharacterOpenBracket,
+/*  92 - \                  */ CharacterBackSlash,
+/*  93 - ]                  */ CharacterCloseBracket,
+/*  94 - ^                  */ CharacterXor,
+/*  95 - _                  */ CharacterIdentifierStart,
+/*  96 - `                  */ CharacterInvalid,
+/*  97 - a                  */ CharacterIdentifierStart,
+/*  98 - b                  */ CharacterIdentifierStart,
+/*  99 - c                  */ CharacterIdentifierStart,
+/* 100 - d                  */ CharacterIdentifierStart,
+/* 101 - e                  */ CharacterIdentifierStart,
+/* 102 - f                  */ CharacterIdentifierStart,
+/* 103 - g                  */ CharacterIdentifierStart,
+/* 104 - h                  */ CharacterIdentifierStart,
+/* 105 - i                  */ CharacterIdentifierStart,
+/* 106 - j                  */ CharacterIdentifierStart,
+/* 107 - k                  */ CharacterIdentifierStart,
+/* 108 - l                  */ CharacterIdentifierStart,
+/* 109 - m                  */ CharacterIdentifierStart,
+/* 110 - n                  */ CharacterIdentifierStart,
+/* 111 - o                  */ CharacterIdentifierStart,
+/* 112 - p                  */ CharacterIdentifierStart,
+/* 113 - q                  */ CharacterIdentifierStart,
+/* 114 - r                  */ CharacterIdentifierStart,
+/* 115 - s                  */ CharacterIdentifierStart,
+/* 116 - t                  */ CharacterIdentifierStart,
+/* 117 - u                  */ CharacterIdentifierStart,
+/* 118 - v                  */ CharacterIdentifierStart,
+/* 119 - w                  */ CharacterIdentifierStart,
+/* 120 - x                  */ CharacterIdentifierStart,
+/* 121 - y                  */ CharacterIdentifierStart,
+/* 122 - z                  */ CharacterIdentifierStart,
+/* 123 - {                  */ CharacterOpenBrace,
+/* 124 - |                  */ CharacterOr,
+/* 125 - }                  */ CharacterCloseBrace,
+/* 126 - ~                  */ CharacterTilde,
+/* 127 - Delete             */ CharacterInvalid,
+};
+
+Lexer::Lexer(JSGlobalData* globalData)
+    : m_isReparsing(false)
+    , m_globalData(globalData)
+    , m_keywordTable(JSC::mainTable)
+{
+}
+
+Lexer::~Lexer()
+{
+    m_keywordTable.deleteTable();
+}
+
+ALWAYS_INLINE const UChar* Lexer::currentCharacter() const
+{
+    ASSERT(m_code <= m_codeEnd);
+    return m_code;
+}
+
+ALWAYS_INLINE int Lexer::currentOffset() const
+{
+    return currentCharacter() - m_codeStart;
+}
+
+void Lexer::setCode(const SourceCode& source, ParserArena& arena)
+{
+    m_arena = &arena.identifierArena();
+
+    m_lineNumber = source.firstLine();
+    m_delimited = false;
+    m_lastToken = -1;
+
+    const UChar* data = source.provider()->data();
+
+    m_source = &source;
+    m_codeStart = data;
+    m_code = data + source.startOffset();
+    m_codeEnd = data + source.endOffset();
+    m_error = false;
+    m_atLineStart = true;
+
+    m_buffer8.reserveInitialCapacity(initialReadBufferCapacity);
+    m_buffer16.reserveInitialCapacity((m_codeEnd - m_code) / 2);
+
+    if (LIKELY(m_code < m_codeEnd))
+        m_current = *m_code;
+    else
+        m_current = -1;
+    ASSERT(currentOffset() == source.startOffset());
+}
+
+ALWAYS_INLINE void Lexer::shift()
+{
+    // Faster than an if-else sequence
+    ASSERT(m_current != -1);
+    m_current = -1;
+    ++m_code;
+    if (LIKELY(m_code < m_codeEnd))
+        m_current = *m_code;
+}
+
+ALWAYS_INLINE int Lexer::peek(int offset)
+{
+    // Only use if necessary
+    ASSERT(offset > 0 && offset < 5);
+    const UChar* code = m_code + offset;
+    return (code < m_codeEnd) ? *code : -1;
+}
+
+int Lexer::getUnicodeCharacter()
+{
+    int char1 = peek(1);
+    int char2 = peek(2);
+    int char3 = peek(3);
+
+    if (UNLIKELY(!isASCIIHexDigit(m_current) || !isASCIIHexDigit(char1) || !isASCIIHexDigit(char2) || !isASCIIHexDigit(char3)))
+        return -1;
+
+    int result = convertUnicode(m_current, char1, char2, char3);
+    shift();
+    shift();
+    shift();
+    shift();
+    return result;
+}
+
+void Lexer::shiftLineTerminator()
+{
+    ASSERT(isLineTerminator(m_current));
+
+    int m_prev = m_current;
+    shift();
+
+    // Allow both CRLF and LFCR.
+    if (m_prev + m_current == '\n' + '\r')
+        shift();
+
+    ++m_lineNumber;
+}
+
+ALWAYS_INLINE const Identifier* Lexer::makeIdentifier(const UChar* characters, size_t length)
+{
+    return &m_arena->makeIdentifier(m_globalData, characters, length);
+}
+
+ALWAYS_INLINE bool Lexer::lastTokenWasRestrKeyword() const
+{
+    return m_lastToken == CONTINUE || m_lastToken == BREAK || m_lastToken == RETURN || m_lastToken == THROW;
+}
+
+static NEVER_INLINE bool isNonASCIIIdentStart(int c)
+{
+    return category(c) & (Letter_Uppercase | Letter_Lowercase | Letter_Titlecase | Letter_Modifier | Letter_Other);
+}
+
+static inline bool isIdentStart(int c)
+{
+    return isASCII(c) ? typesOfASCIICharacters[c] == CharacterIdentifierStart : isNonASCIIIdentStart(c);
+}
+
+static NEVER_INLINE bool isNonASCIIIdentPart(int c)
+{
+    return category(c) & (Letter_Uppercase | Letter_Lowercase | Letter_Titlecase | Letter_Modifier | Letter_Other
+        | Mark_NonSpacing | Mark_SpacingCombining | Number_DecimalDigit | Punctuation_Connector);
+}
+
+static inline bool isIdentPart(int c)
+{
+    // Character types are divided into two groups depending on whether they can be part of an
+    // identifier or not. Those whose type value is less or equal than CharacterNumber can be
+    // part of an identifier. (See the CharacterType definition for more details.)
+    return isASCII(c) ? typesOfASCIICharacters[c] <= CharacterNumber : isNonASCIIIdentPart(c);
+}
+
+static inline int singleEscape(int c)
+{
+    switch (c) {
+    case 'b':
+        return 0x08;
+    case 't':
+        return 0x09;
+    case 'n':
+        return 0x0A;
+    case 'v':
+        return 0x0B;
+    case 'f':
+        return 0x0C;
+    case 'r':
+        return 0x0D;
+    case '\\':
+        return '\\';
+    case '\'':
+        return '\'';
+    case '"':
+        return '"';
+    default:
+        return 0;
+    }
+}
+
+inline void Lexer::record8(int c)
+{
+    ASSERT(c >= 0);
+    ASSERT(c <= 0xFF);
+    m_buffer8.append(static_cast<char>(c));
+}
+
+inline void Lexer::record16(UChar c)
+{
+    m_buffer16.append(c);
+}
+
+inline void Lexer::record16(int c)
+{
+    ASSERT(c >= 0);
+    ASSERT(c <= USHRT_MAX);
+    record16(UChar(static_cast<unsigned short>(c)));
+}
+
+ALWAYS_INLINE bool Lexer::parseString(JSTokenData* lvalp)
+{
+    int stringQuoteCharacter = m_current;
+    shift();
+
+    const UChar* stringStart = currentCharacter();
+
+    while (m_current != stringQuoteCharacter) {
+        if (UNLIKELY(m_current == '\\')) {
+            if (stringStart != currentCharacter())
+                m_buffer16.append(stringStart, currentCharacter() - stringStart);
+            shift();
+
+            int escape = singleEscape(m_current);
+
+            // Most common escape sequences first
+            if (escape) {
+                record16(escape);
+                shift();
+            } else if (UNLIKELY(isLineTerminator(m_current)))
+                shiftLineTerminator();
+            else if (m_current == 'x') {
+                shift();
+                if (isASCIIHexDigit(m_current) && isASCIIHexDigit(peek(1))) {
+                    int prev = m_current;
+                    shift();
+                    record16(convertHex(prev, m_current));
+                    shift();
+                } else
+                    record16('x');
+            } else if (m_current == 'u') {
+                shift();
+                int character = getUnicodeCharacter();
+                if (character != -1)
+                    record16(character);
+                else if (m_current == stringQuoteCharacter)
+                    record16('u');
+                else // Only stringQuoteCharacter allowed after \u
+                    return false;
+            } else if (isASCIIOctalDigit(m_current)) {
+                // Octal character sequences
+                int character1 = m_current;
+                shift();
+                if (isASCIIOctalDigit(m_current)) {
+                    // Two octal characters
+                    int character2 = m_current;
+                    shift();
+                    if (character1 >= '0' && character1 <= '3' && isASCIIOctalDigit(m_current)) {
+                        record16((character1 - '0') * 64 + (character2 - '0') * 8 + m_current - '0');
+                        shift();
+                    } else
+                        record16((character1 - '0') * 8 + character2 - '0');
+                } else
+                    record16(character1 - '0');
+            } else if (m_current != -1) {
+                record16(m_current);
+                shift();
+            } else
+                return false;
+
+            stringStart = currentCharacter();
+            continue;
+        }
+        // Fast check for characters that require special handling.
+        // Catches -1, \n, \r, 0x2028, and 0x2029 as efficiently
+        // as possible, and lets through all common ASCII characters.
+        if (UNLIKELY(((static_cast<unsigned>(m_current) - 0xE) & 0x2000))) {
+            // New-line or end of input is not allowed
+            if (UNLIKELY(isLineTerminator(m_current)) || UNLIKELY(m_current == -1))
+                return false;
+            // Anything else is just a normal character
+        }
+        shift();
+    }
+
+    if (currentCharacter() != stringStart)
+        m_buffer16.append(stringStart, currentCharacter() - stringStart);
+    lvalp->ident = makeIdentifier(m_buffer16.data(), m_buffer16.size());
+    m_buffer16.resize(0);
+    return true;
+}
+
+JSTokenType Lexer::lex(JSTokenData* lvalp, JSTokenInfo* llocp, LexType lexType)
+{
+    ASSERT(!m_error);
+    ASSERT(m_buffer8.isEmpty());
+    ASSERT(m_buffer16.isEmpty());
+
+    JSTokenType token = ERRORTOK;
+    int identChar = 0;
+    m_terminator = false;
+
+start:
+    while (isWhiteSpace(m_current))
+        shift();
+
+    int startOffset = currentOffset();
+
+    if (UNLIKELY(m_current == -1))
+        return EOFTOK;
+
+    m_delimited = false;
+
+    CharacterType type;
+    if (LIKELY(isASCII(m_current)))
+        type = static_cast<CharacterType>(typesOfASCIICharacters[m_current]);
+    else if (isNonASCIIIdentStart(m_current))
+        type = CharacterIdentifierStart;
+    else if (isLineTerminator(m_current))
+        type = CharacterLineTerminator;
+    else
+        type = CharacterInvalid;
+
+    switch (type) {
+    case CharacterGreater:
+        shift();
+        if (m_current == '>') {
+            shift();
+            if (m_current == '>') {
+                shift();
+                if (m_current == '=') {
+                    shift();
+                    token = URSHIFTEQUAL;
+                    break;
+                }
+                token = URSHIFT;
+                break;
+            }
+            if (m_current == '=') {
+                shift();
+                token = RSHIFTEQUAL;
+                break;
+            }
+            token = RSHIFT;
+            break;
+        }
+        if (m_current == '=') {
+            shift();
+            token = GE;
+            break;
+        }
+        token = GT;
+        break;
+    case CharacterEqual:
+        shift();
+        if (m_current == '=') {
+            shift();
+            if (m_current == '=') {
+                shift();
+                token = STREQ;
+                break;
+            }
+            token = EQEQ;
+            break;
+        }
+        token = EQUAL;
+        break;
+    case CharacterLess:
+        shift();
+        if (m_current == '!' && peek(1) == '-' && peek(2) == '-') {
+            // <!-- marks the beginning of a line comment (for www usage)
+            goto inSingleLineComment;
+        }
+        if (m_current == '<') {
+            shift();
+            if (m_current == '=') {
+                shift();
+                token = LSHIFTEQUAL;
+                break;
+            }
+            token = LSHIFT;
+            break;
+        }
+        if (m_current == '=') {
+            shift();
+            token = LE;
+            break;
+        }
+        token = LT;
+        break;
+    case CharacterExclamationMark:
+        shift();
+        if (m_current == '=') {
+            shift();
+            if (m_current == '=') {
+                shift();
+                token = STRNEQ;
+                break;
+            }
+            token = NE;
+            break;
+        }
+        token = EXCLAMATION;
+        break;
+    case CharacterAdd:
+        shift();
+        if (m_current == '+') {
+            shift();
+            token = (!m_terminator) ? PLUSPLUS : AUTOPLUSPLUS;
+            break;
+        }
+        if (m_current == '=') {
+            shift();
+            token = PLUSEQUAL;
+            break;
+        }
+        token = PLUS;
+        break;
+    case CharacterSub:
+        shift();
+        if (m_current == '-') {
+            shift();
+            if (m_atLineStart && m_current == '>') {
+                shift();
+                goto inSingleLineComment;
+            }
+            token = (!m_terminator) ? MINUSMINUS : AUTOMINUSMINUS;
+            break;
+        }
+        if (m_current == '=') {
+            shift();
+            token = MINUSEQUAL;
+            break;
+        }
+        token = MINUS;
+        break;
+    case CharacterMultiply:
+        shift();
+        if (m_current == '=') {
+            shift();
+            token = MULTEQUAL;
+            break;
+        }
+        token = TIMES;
+        break;
+    case CharacterSlash:
+        shift();
+        if (m_current == '/') {
+            shift();
+            goto inSingleLineComment;
+        }
+        if (m_current == '*') {
+            shift();
+            goto inMultiLineComment;
+        }
+        if (m_current == '=') {
+            shift();
+            token = DIVEQUAL;
+            break;
+        }
+        token = DIVIDE;
+        break;
+    case CharacterAnd:
+        shift();
+        if (m_current == '&') {
+            shift();
+            token = AND;
+            break;
+        }
+        if (m_current == '=') {
+            shift();
+            token = ANDEQUAL;
+            break;
+        }
+        token = BITAND;
+        break;
+    case CharacterXor:
+        shift();
+        if (m_current == '=') {
+            shift();
+            token = XOREQUAL;
+            break;
+        }
+        token = BITXOR;
+        break;
+    case CharacterModulo:
+        shift();
+        if (m_current == '=') {
+            shift();
+            token = MODEQUAL;
+            break;
+        }
+        token = MOD;
+        break;
+    case CharacterOr:
+        shift();
+        if (m_current == '=') {
+            shift();
+            token = OREQUAL;
+            break;
+        }
+        if (m_current == '|') {
+            shift();
+            token = OR;
+            break;
+        }
+        token = BITOR;
+        break;
+    case CharacterDot:
+        shift();
+        if (isASCIIDigit(m_current)) {
+            record8('.');
+            goto inNumberAfterDecimalPoint;
+        }
+        token = DOT;
+        break;
+    case CharacterOpenParen:
+        token = OPENPAREN;
+        shift();
+        break;
+    case CharacterCloseParen:
+        token = CLOSEPAREN;
+        shift();
+        break;
+    case CharacterOpenBracket:
+        token = OPENBRACKET;
+        shift();
+        break;
+    case CharacterCloseBracket:
+        token = CLOSEBRACKET;
+        shift();
+        break;
+    case CharacterComma:
+        token = COMMA;
+        shift();
+        break;
+    case CharacterColon:
+        token = COLON;
+        shift();
+        break;
+    case CharacterQuestion:
+        token = QUESTION;
+        shift();
+        break;
+    case CharacterTilde:
+        token = TILDE;
+        shift();
+        break;
+    case CharacterSemicolon:
+        m_delimited = true;
+        shift();
+        token = SEMICOLON;
+        break;
+    case CharacterOpenBrace:
+        lvalp->intValue = currentOffset();
+        shift();
+        token = OPENBRACE;
+        break;
+    case CharacterCloseBrace:
+        lvalp->intValue = currentOffset();
+        m_delimited = true;
+        shift();
+        token = CLOSEBRACE;
+        break;
+    case CharacterBackSlash:
+        goto startIdentifierWithBackslash;
+    case CharacterZero:
+        goto startNumberWithZeroDigit;
+    case CharacterNumber:
+        goto startNumber;
+    case CharacterQuote:
+        if (UNLIKELY(!parseString(lvalp)))
+            goto returnError;
+        shift();
+        m_delimited = false;
+        token = STRING;
+        break;
+    case CharacterIdentifierStart:
+        ASSERT(isIdentStart(m_current));
+        goto startIdentifierOrKeyword;
+    case CharacterLineTerminator:
+        ASSERT(isLineTerminator(m_current));
+        shiftLineTerminator();
+        m_atLineStart = true;
+        m_terminator = true;
+        if (lastTokenWasRestrKeyword()) {
+            token = SEMICOLON;
+            goto doneSemicolon;
+        }
+        goto start;
+    case CharacterInvalid:
+        goto returnError;
+    default:
+        ASSERT_NOT_REACHED();
+        goto returnError;
+    }
+
+    m_atLineStart = false;
+    goto returnToken;
+
+startIdentifierWithBackslash: {
+    shift();
+    if (UNLIKELY(m_current != 'u'))
+        goto returnError;
+    shift();
+
+    identChar = getUnicodeCharacter();
+    if (UNLIKELY(identChar == -1))
+        goto returnError;
+    if (UNLIKELY(!isIdentStart(identChar)))
+        goto returnError;
+    goto inIdentifierAfterCharacterCheck;
+}
+
+startIdentifierOrKeyword: {
+    const UChar* identifierStart = currentCharacter();
+    shift();
+    while (isIdentPart(m_current))
+        shift();
+    if (LIKELY(m_current != '\\')) {
+        // Fast case for idents which does not contain \uCCCC characters
+        lvalp->ident = makeIdentifier(identifierStart, currentCharacter() - identifierStart);
+        goto doneIdentifierOrKeyword;
+    }
+    m_buffer16.append(identifierStart, currentCharacter() - identifierStart);
+}
+
+    do {
+        shift();
+        if (UNLIKELY(m_current != 'u'))
+            goto returnError;
+        shift();
+        identChar = getUnicodeCharacter();
+        if (UNLIKELY(identChar == -1))
+            goto returnError;
+        if (UNLIKELY(!isIdentPart(identChar)))
+            goto returnError;
+inIdentifierAfterCharacterCheck:
+        record16(identChar);
+
+        while (isIdentPart(m_current)) {
+            record16(m_current);
+            shift();
+        }
+    } while (UNLIKELY(m_current == '\\'));
+    goto doneIdentifier;
+
+inSingleLineComment:
+    while (!isLineTerminator(m_current)) {
+        if (UNLIKELY(m_current == -1))
+            return EOFTOK;
+        shift();
+    }
+    shiftLineTerminator();
+    m_atLineStart = true;
+    m_terminator = true;
+    if (lastTokenWasRestrKeyword())
+        goto doneSemicolon;
+    goto start;
+
+inMultiLineComment:
+    while (true) {
+        if (UNLIKELY(m_current == '*')) {
+            shift();
+            if (m_current == '/')
+                break;
+            if (m_current == '*')
+                continue;
+        }
+
+        if (UNLIKELY(m_current == -1))
+            goto returnError;
+
+        if (isLineTerminator(m_current))
+            shiftLineTerminator();
+        else
+            shift();
+    }
+    shift();
+    m_atLineStart = false;
+    goto start;
+
+startNumberWithZeroDigit:
+    shift();
+    if ((m_current | 0x20) == 'x' && isASCIIHexDigit(peek(1))) {
+        shift();
+        goto inHex;
+    }
+    if (m_current == '.') {
+        record8('0');
+        record8('.');
+        shift();
+        goto inNumberAfterDecimalPoint;
+    }
+    if ((m_current | 0x20) == 'e') {
+        record8('0');
+        record8('e');
+        shift();
+        goto inExponentIndicator;
+    }
+    if (isASCIIOctalDigit(m_current))
+        goto inOctal;
+    if (isASCIIDigit(m_current))
+        goto startNumber;
+    lvalp->doubleValue = 0;
+    goto doneNumeric;
+
+inNumberAfterDecimalPoint:
+    while (isASCIIDigit(m_current)) {
+        record8(m_current);
+        shift();
+    }
+    if ((m_current | 0x20) == 'e') {
+        record8('e');
+        shift();
+        goto inExponentIndicator;
+    }
+    goto doneNumber;
+
+inExponentIndicator:
+    if (m_current == '+' || m_current == '-') {
+        record8(m_current);
+        shift();
+    }
+    if (!isASCIIDigit(m_current))
+        goto returnError;
+    do {
+        record8(m_current);
+        shift();
+    } while (isASCIIDigit(m_current));
+    goto doneNumber;
+
+inOctal: {
+    do {
+        record8(m_current);
+        shift();
+    } while (isASCIIOctalDigit(m_current));
+    if (isASCIIDigit(m_current))
+        goto startNumber;
+
+    double dval = 0;
+
+    const char* end = m_buffer8.end();
+    for (const char* p = m_buffer8.data(); p < end; ++p) {
+        dval *= 8;
+        dval += *p - '0';
+    }
+    if (dval >= mantissaOverflowLowerBound)
+        dval = parseIntOverflow(m_buffer8.data(), end - m_buffer8.data(), 8);
+
+    m_buffer8.resize(0);
+
+    lvalp->doubleValue = dval;
+    goto doneNumeric;
+}
+
+inHex: {
+    do {
+        record8(m_current);
+        shift();
+    } while (isASCIIHexDigit(m_current));
+
+    double dval = 0;
+
+    const char* end = m_buffer8.end();
+    for (const char* p = m_buffer8.data(); p < end; ++p) {
+        dval *= 16;
+        dval += toASCIIHexValue(*p);
+    }
+    if (dval >= mantissaOverflowLowerBound)
+        dval = parseIntOverflow(m_buffer8.data(), end - m_buffer8.data(), 16);
+
+    m_buffer8.resize(0);
+
+    lvalp->doubleValue = dval;
+    goto doneNumeric;
+}
+
+startNumber:
+    record8(m_current);
+    shift();
+    while (isASCIIDigit(m_current)) {
+        record8(m_current);
+        shift();
+    }
+    if (m_current == '.') {
+        record8('.');
+        shift();
+        goto inNumberAfterDecimalPoint;
+    }
+    if ((m_current | 0x20) == 'e') {
+        record8('e');
+        shift();
+        goto inExponentIndicator;
+    }
+
+    // Fall through into doneNumber.
+
+doneNumber:
+    // Null-terminate string for strtod.
+    m_buffer8.append('\0');
+    lvalp->doubleValue = WTF::strtod(m_buffer8.data(), 0);
+    m_buffer8.resize(0);
+
+    // Fall through into doneNumeric.
+
+doneNumeric:
+    // No identifiers allowed directly after numeric literal, e.g. "3in" is bad.
+    if (UNLIKELY(isIdentStart(m_current)))
+        goto returnError;
+
+    m_atLineStart = false;
+    m_delimited = false;
+    token = NUMBER;
+    goto returnToken;
+
+doneSemicolon:
+    token = SEMICOLON;
+    m_delimited = true;
+    goto returnToken;
+
+doneIdentifier:
+    m_atLineStart = false;
+    m_delimited = false;
+    lvalp->ident = makeIdentifier(m_buffer16.data(), m_buffer16.size());
+    m_buffer16.resize(0);
+    token = IDENT;
+    goto returnToken;
+
+doneIdentifierOrKeyword: {
+    m_atLineStart = false;
+    m_delimited = false;
+    m_buffer16.resize(0);
+    if (lexType == IdentifyReservedWords) {
+        const HashEntry* entry = m_keywordTable.entry(m_globalData, *lvalp->ident);
+        token = entry ? static_cast<JSTokenType>(entry->lexerValue()) : IDENT;
+    } else
+        token = IDENT;
+    // Fall through into returnToken.
+}
+
+returnToken: {
+    int lineNumber = m_lineNumber;
+    llocp->line = lineNumber;
+    llocp->startOffset = startOffset;
+    llocp->endOffset = currentOffset();
+    m_lastToken = token;
+    return token;
+}
+
+returnError:
+    m_error = true;
+    return ERRORTOK;
+}
+
+bool Lexer::scanRegExp(const Identifier*& pattern, const Identifier*& flags, UChar patternPrefix)
+{
+    ASSERT(m_buffer16.isEmpty());
+
+    bool lastWasEscape = false;
+    bool inBrackets = false;
+
+    if (patternPrefix) {
+        ASSERT(!isLineTerminator(patternPrefix));
+        ASSERT(patternPrefix != '/');
+        ASSERT(patternPrefix != '[');
+        record16(patternPrefix);
+    }
+
+    while (true) {
+        int current = m_current;
+
+        if (isLineTerminator(current) || current == -1) {
+            m_buffer16.resize(0);
+            return false;
+        }
+
+        shift();
+
+        if (current == '/' && !lastWasEscape && !inBrackets)
+            break;
+
+        record16(current);
+
+        if (lastWasEscape) {
+            lastWasEscape = false;
+            continue;
+        }
+
+        switch (current) {
+        case '[':
+            inBrackets = true;
+            break;
+        case ']':
+            inBrackets = false;
+            break;
+        case '\\':
+            lastWasEscape = true;
+            break;
+        }
+    }
+
+    pattern = makeIdentifier(m_buffer16.data(), m_buffer16.size());
+    m_buffer16.resize(0);
+
+    while (isIdentPart(m_current)) {
+        record16(m_current);
+        shift();
+    }
+
+    flags = makeIdentifier(m_buffer16.data(), m_buffer16.size());
+    m_buffer16.resize(0);
+
+    return true;
+}
+
+bool Lexer::skipRegExp()
+{
+    bool lastWasEscape = false;
+    bool inBrackets = false;
+
+    while (true) {
+        int current = m_current;
+
+        if (isLineTerminator(current) || current == -1)
+            return false;
+
+        shift();
+
+        if (current == '/' && !lastWasEscape && !inBrackets)
+            break;
+
+        if (lastWasEscape) {
+            lastWasEscape = false;
+            continue;
+        }
+
+        switch (current) {
+        case '[':
+            inBrackets = true;
+            break;
+        case ']':
+            inBrackets = false;
+            break;
+        case '\\':
+            lastWasEscape = true;
+            break;
+        }
+    }
+
+    while (isIdentPart(m_current))
+        shift();
+
+    return true;
+}
+
+void Lexer::clear()
+{
+    m_arena = 0;
+
+    Vector<char> newBuffer8;
+    m_buffer8.swap(newBuffer8);
+
+    Vector<UChar> newBuffer16;
+    m_buffer16.swap(newBuffer16);
+
+    m_isReparsing = false;
+}
+
+SourceCode Lexer::sourceCode(int openBrace, int closeBrace, int firstLine)
+{
+    ASSERT(m_source->provider()->data()[openBrace] == '{');
+    ASSERT(m_source->provider()->data()[closeBrace] == '}');
+    return SourceCode(m_source->provider(), openBrace, closeBrace + 1, firstLine);
+}
+
+} // namespace JSC