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Unified Diff: src/scanner-base.cc

Issue 5136002: Extract scanner base/JS/JSON and move base and JS to scanner-base. (Closed)
Patch Set: Created 10 years, 1 month ago
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Index: src/scanner-base.cc
diff --git a/src/scanner-base.cc b/src/scanner-base.cc
index 6cde51787f5d50cf0199ce0ab5e5609fac53087d..377de342d137e94aa1cb35d5c72642e156ea010c 100644
--- a/src/scanner-base.cc
+++ b/src/scanner-base.cc
@@ -29,11 +29,40 @@
#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;
@@ -61,6 +90,690 @@ bool ScannerConstants::IsIdentifier(unibrow::CharacterStream* buffer) {
}
// ----------------------------------------------------------------------------
+// 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 = ScanIdentifier();
+ } 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);
+ 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);
+ 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::ScanIdentifier() {
+ ASSERT(ScannerConstants::kIsIdentifierStart.get(c0_));
+
+ LiteralScope literal(this);
+ 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();
+ }
+
+ // 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);
+ keyword_match.Fail();
+ } else {
+ AddLiteralChar(c0_);
+ keyword_match.AddChar(c0_);
+ Advance();
+ }
+ }
+ literal.Complete();
+
+ return keyword_match.token();
+}
+
+
+
+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);
+ 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);
+ 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_[] = {
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