diff options
Diffstat (limited to 'src/scanner-base.cc')
| -rw-r--r-- | src/scanner-base.cc | 762 |
1 files changed, 759 insertions, 3 deletions
diff --git a/src/scanner-base.cc b/src/scanner-base.cc index 6e9d40e0..8242f81c 100644 --- a/src/scanner-base.cc +++ b/src/scanner-base.cc @@ -27,12 +27,770 @@ // Features shared by parsing and pre-parsing scanners. +#include "../include/v8stdint.h" #include "scanner-base.h" +#include "char-predicates-inl.h" namespace v8 { namespace internal { // ---------------------------------------------------------------------------- +// UTF16Buffer + +UTF16Buffer::UTF16Buffer() + : pos_(0), end_(kNoEndPosition) { } + +// ---------------------------------------------------------------------------- +// LiteralCollector + +LiteralCollector::LiteralCollector() + : buffer_(kInitialCapacity), recording_(false) { } + + +LiteralCollector::~LiteralCollector() {} + + +void LiteralCollector::AddCharSlow(uc32 c) { + ASSERT(static_cast<unsigned>(c) > unibrow::Utf8::kMaxOneByteChar); + int length = unibrow::Utf8::Length(c); + Vector<char> block = buffer_.AddBlock(length, '\0'); +#ifdef DEBUG + int written_length = unibrow::Utf8::Encode(block.start(), c); + CHECK_EQ(length, written_length); +#else + unibrow::Utf8::Encode(block.start(), c); +#endif +} + +// ---------------------------------------------------------------------------- +// Character predicates + +unibrow::Predicate<IdentifierStart, 128> ScannerConstants::kIsIdentifierStart; +unibrow::Predicate<IdentifierPart, 128> ScannerConstants::kIsIdentifierPart; +unibrow::Predicate<unibrow::WhiteSpace, 128> ScannerConstants::kIsWhiteSpace; +unibrow::Predicate<unibrow::LineTerminator, 128> + ScannerConstants::kIsLineTerminator; + +StaticResource<ScannerConstants::Utf8Decoder> ScannerConstants::utf8_decoder_; + +// Compound predicates. + +bool ScannerConstants::IsIdentifier(unibrow::CharacterStream* buffer) { + // Checks whether the buffer contains an identifier (no escape). + if (!buffer->has_more()) return false; + if (!kIsIdentifierStart.get(buffer->GetNext())) { + return false; + } + while (buffer->has_more()) { + if (!kIsIdentifierPart.get(buffer->GetNext())) { + return false; + } + } + return true; +} + +// ---------------------------------------------------------------------------- +// Scanner + +Scanner::Scanner() : source_(NULL), stack_overflow_(false) {} + + +uc32 Scanner::ScanHexEscape(uc32 c, int length) { + ASSERT(length <= 4); // prevent overflow + + uc32 digits[4]; + uc32 x = 0; + for (int i = 0; i < length; i++) { + digits[i] = c0_; + int d = HexValue(c0_); + if (d < 0) { + // According to ECMA-262, 3rd, 7.8.4, page 18, these hex escapes + // should be illegal, but other JS VMs just return the + // non-escaped version of the original character. + + // Push back digits read, except the last one (in c0_). + for (int j = i-1; j >= 0; j--) { + PushBack(digits[j]); + } + // Notice: No handling of error - treat it as "\u"->"u". + return c; + } + x = x * 16 + d; + Advance(); + } + + return x; +} + + +// Octal escapes of the forms '\0xx' and '\xxx' are not a part of +// ECMA-262. Other JS VMs support them. +uc32 Scanner::ScanOctalEscape(uc32 c, int length) { + uc32 x = c - '0'; + for (int i = 0; i < length; i++) { + int d = c0_ - '0'; + if (d < 0 || d > 7) break; + int nx = x * 8 + d; + if (nx >= 256) break; + x = nx; + Advance(); + } + return x; +} + + +// ---------------------------------------------------------------------------- +// JavaScriptScanner + +JavaScriptScanner::JavaScriptScanner() + : has_line_terminator_before_next_(false) {} + + +Token::Value JavaScriptScanner::Next() { + current_ = next_; + has_line_terminator_before_next_ = false; + Scan(); + return current_.token; +} + + +static inline bool IsByteOrderMark(uc32 c) { + // The Unicode value U+FFFE is guaranteed never to be assigned as a + // Unicode character; this implies that in a Unicode context the + // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF + // character expressed in little-endian byte order (since it could + // not be a U+FFFE character expressed in big-endian byte + // order). Nevertheless, we check for it to be compatible with + // Spidermonkey. + return c == 0xFEFF || c == 0xFFFE; +} + + +bool JavaScriptScanner::SkipWhiteSpace() { + int start_position = source_pos(); + + while (true) { + // We treat byte-order marks (BOMs) as whitespace for better + // compatibility with Spidermonkey and other JavaScript engines. + while (ScannerConstants::kIsWhiteSpace.get(c0_) || IsByteOrderMark(c0_)) { + // IsWhiteSpace() includes line terminators! + if (ScannerConstants::kIsLineTerminator.get(c0_)) { + // Ignore line terminators, but remember them. This is necessary + // for automatic semicolon insertion. + has_line_terminator_before_next_ = true; + } + Advance(); + } + + // If there is an HTML comment end '-->' at the beginning of a + // line (with only whitespace in front of it), we treat the rest + // of the line as a comment. This is in line with the way + // SpiderMonkey handles it. + if (c0_ == '-' && has_line_terminator_before_next_) { + Advance(); + if (c0_ == '-') { + Advance(); + if (c0_ == '>') { + // Treat the rest of the line as a comment. + SkipSingleLineComment(); + // Continue skipping white space after the comment. + continue; + } + PushBack('-'); // undo Advance() + } + PushBack('-'); // undo Advance() + } + // Return whether or not we skipped any characters. + return source_pos() != start_position; + } +} + + +Token::Value JavaScriptScanner::SkipSingleLineComment() { + Advance(); + + // The line terminator at the end of the line is not considered + // to be part of the single-line comment; it is recognized + // separately by the lexical grammar and becomes part of the + // stream of input elements for the syntactic grammar (see + // ECMA-262, section 7.4, page 12). + while (c0_ >= 0 && !ScannerConstants::kIsLineTerminator.get(c0_)) { + Advance(); + } + + return Token::WHITESPACE; +} + + +Token::Value JavaScriptScanner::SkipMultiLineComment() { + ASSERT(c0_ == '*'); + Advance(); + + while (c0_ >= 0) { + char ch = c0_; + Advance(); + // If we have reached the end of the multi-line comment, we + // consume the '/' and insert a whitespace. This way all + // multi-line comments are treated as whitespace - even the ones + // containing line terminators. This contradicts ECMA-262, section + // 7.4, page 12, that says that multi-line comments containing + // line terminators should be treated as a line terminator, but it + // matches the behaviour of SpiderMonkey and KJS. + if (ch == '*' && c0_ == '/') { + c0_ = ' '; + return Token::WHITESPACE; + } + } + + // Unterminated multi-line comment. + return Token::ILLEGAL; +} + + +Token::Value JavaScriptScanner::ScanHtmlComment() { + // Check for <!-- comments. + ASSERT(c0_ == '!'); + Advance(); + if (c0_ == '-') { + Advance(); + if (c0_ == '-') return SkipSingleLineComment(); + PushBack('-'); // undo Advance() + } + PushBack('!'); // undo Advance() + ASSERT(c0_ == '!'); + return Token::LT; +} + + +void JavaScriptScanner::Scan() { + next_.literal_chars = Vector<const char>(); + Token::Value token; + do { + // Remember the position of the next token + next_.location.beg_pos = source_pos(); + + switch (c0_) { + case ' ': + case '\t': + Advance(); + token = Token::WHITESPACE; + break; + + case '\n': + Advance(); + has_line_terminator_before_next_ = true; + token = Token::WHITESPACE; + break; + + case '"': case '\'': + token = ScanString(); + break; + + case '<': + // < <= << <<= <!-- + Advance(); + if (c0_ == '=') { + token = Select(Token::LTE); + } else if (c0_ == '<') { + token = Select('=', Token::ASSIGN_SHL, Token::SHL); + } else if (c0_ == '!') { + token = ScanHtmlComment(); + } else { + token = Token::LT; + } + break; + + case '>': + // > >= >> >>= >>> >>>= + Advance(); + if (c0_ == '=') { + token = Select(Token::GTE); + } else if (c0_ == '>') { + // >> >>= >>> >>>= + Advance(); + if (c0_ == '=') { + token = Select(Token::ASSIGN_SAR); + } else if (c0_ == '>') { + token = Select('=', Token::ASSIGN_SHR, Token::SHR); + } else { + token = Token::SAR; + } + } else { + token = Token::GT; + } + break; + + case '=': + // = == === + Advance(); + if (c0_ == '=') { + token = Select('=', Token::EQ_STRICT, Token::EQ); + } else { + token = Token::ASSIGN; + } + break; + + case '!': + // ! != !== + Advance(); + if (c0_ == '=') { + token = Select('=', Token::NE_STRICT, Token::NE); + } else { + token = Token::NOT; + } + break; + + case '+': + // + ++ += + Advance(); + if (c0_ == '+') { + token = Select(Token::INC); + } else if (c0_ == '=') { + token = Select(Token::ASSIGN_ADD); + } else { + token = Token::ADD; + } + break; + + case '-': + // - -- --> -= + Advance(); + if (c0_ == '-') { + Advance(); + if (c0_ == '>' && has_line_terminator_before_next_) { + // For compatibility with SpiderMonkey, we skip lines that + // start with an HTML comment end '-->'. + token = SkipSingleLineComment(); + } else { + token = Token::DEC; + } + } else if (c0_ == '=') { + token = Select(Token::ASSIGN_SUB); + } else { + token = Token::SUB; + } + break; + + case '*': + // * *= + token = Select('=', Token::ASSIGN_MUL, Token::MUL); + break; + + case '%': + // % %= + token = Select('=', Token::ASSIGN_MOD, Token::MOD); + break; + + case '/': + // / // /* /= + Advance(); + if (c0_ == '/') { + token = SkipSingleLineComment(); + } else if (c0_ == '*') { + token = SkipMultiLineComment(); + } else if (c0_ == '=') { + token = Select(Token::ASSIGN_DIV); + } else { + token = Token::DIV; + } + break; + + case '&': + // & && &= + Advance(); + if (c0_ == '&') { + token = Select(Token::AND); + } else if (c0_ == '=') { + token = Select(Token::ASSIGN_BIT_AND); + } else { + token = Token::BIT_AND; + } + break; + + case '|': + // | || |= + Advance(); + if (c0_ == '|') { + token = Select(Token::OR); + } else if (c0_ == '=') { + token = Select(Token::ASSIGN_BIT_OR); + } else { + token = Token::BIT_OR; + } + break; + + case '^': + // ^ ^= + token = Select('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR); + break; + + case '.': + // . Number + Advance(); + if (IsDecimalDigit(c0_)) { + token = ScanNumber(true); + } else { + token = Token::PERIOD; + } + break; + + case ':': + token = Select(Token::COLON); + break; + + case ';': + token = Select(Token::SEMICOLON); + break; + + case ',': + token = Select(Token::COMMA); + break; + + case '(': + token = Select(Token::LPAREN); + break; + + case ')': + token = Select(Token::RPAREN); + break; + + case '[': + token = Select(Token::LBRACK); + break; + + case ']': + token = Select(Token::RBRACK); + break; + + case '{': + token = Select(Token::LBRACE); + break; + + case '}': + token = Select(Token::RBRACE); + break; + + case '?': + token = Select(Token::CONDITIONAL); + break; + + case '~': + token = Select(Token::BIT_NOT); + break; + + default: + if (ScannerConstants::kIsIdentifierStart.get(c0_)) { + token = ScanIdentifierOrKeyword(); + } else if (IsDecimalDigit(c0_)) { + token = ScanNumber(false); + } else if (SkipWhiteSpace()) { + token = Token::WHITESPACE; + } else if (c0_ < 0) { + token = Token::EOS; + } else { + token = Select(Token::ILLEGAL); + } + break; + } + + // Continue scanning for tokens as long as we're just skipping + // whitespace. + } while (token == Token::WHITESPACE); + + next_.location.end_pos = source_pos(); + next_.token = token; +} + + +void JavaScriptScanner::SeekForward(int pos) { + source_->SeekForward(pos - 1); + Advance(); + // This function is only called to seek to the location + // of the end of a function (at the "}" token). It doesn't matter + // whether there was a line terminator in the part we skip. + has_line_terminator_before_next_ = false; + Scan(); +} + + +void JavaScriptScanner::ScanEscape() { + uc32 c = c0_; + Advance(); + + // Skip escaped newlines. + if (ScannerConstants::kIsLineTerminator.get(c)) { + // Allow CR+LF newlines in multiline string literals. + if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance(); + // Allow LF+CR newlines in multiline string literals. + if (IsLineFeed(c) && IsCarriageReturn(c0_)) Advance(); + return; + } + + switch (c) { + case '\'': // fall through + case '"' : // fall through + case '\\': break; + case 'b' : c = '\b'; break; + case 'f' : c = '\f'; break; + case 'n' : c = '\n'; break; + case 'r' : c = '\r'; break; + case 't' : c = '\t'; break; + case 'u' : c = ScanHexEscape(c, 4); break; + case 'v' : c = '\v'; break; + case 'x' : c = ScanHexEscape(c, 2); break; + case '0' : // fall through + case '1' : // fall through + case '2' : // fall through + case '3' : // fall through + case '4' : // fall through + case '5' : // fall through + case '6' : // fall through + case '7' : c = ScanOctalEscape(c, 2); break; + } + + // According to ECMA-262, 3rd, 7.8.4 (p 18ff) these + // should be illegal, but they are commonly handled + // as non-escaped characters by JS VMs. + AddLiteralChar(c); +} + + +Token::Value JavaScriptScanner::ScanString() { + uc32 quote = c0_; + Advance(); // consume quote + + LiteralScope literal(this, kLiteralString); + while (c0_ != quote && c0_ >= 0 + && !ScannerConstants::kIsLineTerminator.get(c0_)) { + uc32 c = c0_; + Advance(); + if (c == '\\') { + if (c0_ < 0) return Token::ILLEGAL; + ScanEscape(); + } else { + AddLiteralChar(c); + } + } + if (c0_ != quote) return Token::ILLEGAL; + literal.Complete(); + + Advance(); // consume quote + return Token::STRING; +} + + +void JavaScriptScanner::ScanDecimalDigits() { + while (IsDecimalDigit(c0_)) + AddLiteralCharAdvance(); +} + + +Token::Value JavaScriptScanner::ScanNumber(bool seen_period) { + ASSERT(IsDecimalDigit(c0_)); // the first digit of the number or the fraction + + enum { DECIMAL, HEX, OCTAL } kind = DECIMAL; + + LiteralScope literal(this, kLiteralNumber); + if (seen_period) { + // we have already seen a decimal point of the float + AddLiteralChar('.'); + ScanDecimalDigits(); // we know we have at least one digit + + } else { + // if the first character is '0' we must check for octals and hex + if (c0_ == '0') { + AddLiteralCharAdvance(); + + // either 0, 0exxx, 0Exxx, 0.xxx, an octal number, or a hex number + if (c0_ == 'x' || c0_ == 'X') { + // hex number + kind = HEX; + AddLiteralCharAdvance(); + if (!IsHexDigit(c0_)) { + // we must have at least one hex digit after 'x'/'X' + return Token::ILLEGAL; + } + while (IsHexDigit(c0_)) { + AddLiteralCharAdvance(); + } + } else if ('0' <= c0_ && c0_ <= '7') { + // (possible) octal number + kind = OCTAL; + while (true) { + if (c0_ == '8' || c0_ == '9') { + kind = DECIMAL; + break; + } + if (c0_ < '0' || '7' < c0_) break; + AddLiteralCharAdvance(); + } + } + } + + // Parse decimal digits and allow trailing fractional part. + if (kind == DECIMAL) { + ScanDecimalDigits(); // optional + if (c0_ == '.') { + AddLiteralCharAdvance(); + ScanDecimalDigits(); // optional + } + } + } + + // scan exponent, if any + if (c0_ == 'e' || c0_ == 'E') { + ASSERT(kind != HEX); // 'e'/'E' must be scanned as part of the hex number + if (kind == OCTAL) return Token::ILLEGAL; // no exponent for octals allowed + // scan exponent + AddLiteralCharAdvance(); + if (c0_ == '+' || c0_ == '-') + AddLiteralCharAdvance(); + if (!IsDecimalDigit(c0_)) { + // we must have at least one decimal digit after 'e'/'E' + return Token::ILLEGAL; + } + ScanDecimalDigits(); + } + + // The source character immediately following a numeric literal must + // not be an identifier start or a decimal digit; see ECMA-262 + // section 7.8.3, page 17 (note that we read only one decimal digit + // if the value is 0). + if (IsDecimalDigit(c0_) || ScannerConstants::kIsIdentifierStart.get(c0_)) + return Token::ILLEGAL; + + literal.Complete(); + + return Token::NUMBER; +} + + +uc32 JavaScriptScanner::ScanIdentifierUnicodeEscape() { + Advance(); + if (c0_ != 'u') return unibrow::Utf8::kBadChar; + Advance(); + uc32 c = ScanHexEscape('u', 4); + // We do not allow a unicode escape sequence to start another + // unicode escape sequence. + if (c == '\\') return unibrow::Utf8::kBadChar; + return c; +} + + +Token::Value JavaScriptScanner::ScanIdentifierOrKeyword() { + ASSERT(ScannerConstants::kIsIdentifierStart.get(c0_)); + 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); + 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_ == '\\') { + uc32 c = ScanIdentifierUnicodeEscape(); + // Only allow legal identifier part characters. + if (!ScannerConstants::kIsIdentifierPart.get(c)) return Token::ILLEGAL; + AddLiteralChar(c); + } else { + AddLiteralChar(c0_); + Advance(); + } + } + literal->Complete(); + + return Token::IDENTIFIER; +} + + +bool JavaScriptScanner::ScanRegExpPattern(bool seen_equal) { + // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags + bool in_character_class = false; + + // Previous token is either '/' or '/=', in the second case, the + // pattern starts at =. + next_.location.beg_pos = source_pos() - (seen_equal ? 2 : 1); + next_.location.end_pos = source_pos() - (seen_equal ? 1 : 0); + + // 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, kLiteralRegExp); + if (seen_equal) + AddLiteralChar('='); + + while (c0_ != '/' || in_character_class) { + if (ScannerConstants::kIsLineTerminator.get(c0_) || c0_ < 0) return false; + if (c0_ == '\\') { // escaped character + AddLiteralCharAdvance(); + if (ScannerConstants::kIsLineTerminator.get(c0_) || c0_ < 0) return false; + AddLiteralCharAdvance(); + } else { // unescaped character + if (c0_ == '[') in_character_class = true; + if (c0_ == ']') in_character_class = false; + AddLiteralCharAdvance(); + } + } + Advance(); // consume '/' + + literal.Complete(); + + return true; +} + + +bool JavaScriptScanner::ScanRegExpFlags() { + // Scan regular expression flags. + LiteralScope literal(this, kLiteralRegExpFlags); + while (ScannerConstants::kIsIdentifierPart.get(c0_)) { + if (c0_ == '\\') { + uc32 c = ScanIdentifierUnicodeEscape(); + if (c != static_cast<uc32>(unibrow::Utf8::kBadChar)) { + // We allow any escaped character, unlike the restriction on + // IdentifierPart when it is used to build an IdentifierName. + AddLiteralChar(c); + continue; + } + } + AddLiteralCharAdvance(); + } + literal.Complete(); + + next_.location.end_pos = source_pos() - 1; + return true; +} + +// ---------------------------------------------------------------------------- // Keyword Matcher KeywordMatcher::FirstState KeywordMatcher::first_states_[] = { @@ -127,9 +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; |