1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 // Features shared by parsing and pre-parsing scanners.
6
7 #include "src/parsing/scanner.h"
8
9 #include <stdint.h>
10
11 #include <cmath>
12
13 #include "src/ast/ast-value-factory.h"
14 #include "src/char-predicates-inl.h"
15 #include "src/conversions-inl.h"
16 #include "src/list-inl.h"
17 #include "src/parsing/parser.h"
18
19 namespace v8 {
20 namespace internal {
21
22
Internalize(Isolate * isolate) const23 Handle<String> LiteralBuffer::Internalize(Isolate* isolate) const {
24 if (is_one_byte()) {
25 return isolate->factory()->InternalizeOneByteString(one_byte_literal());
26 }
27 return isolate->factory()->InternalizeTwoByteString(two_byte_literal());
28 }
29
30
31 // Default implementation for streams that do not support bookmarks.
SetBookmark()32 bool Utf16CharacterStream::SetBookmark() { return false; }
ResetToBookmark()33 void Utf16CharacterStream::ResetToBookmark() { UNREACHABLE(); }
34
35
36 // ----------------------------------------------------------------------------
37 // Scanner
38
Scanner(UnicodeCache * unicode_cache)39 Scanner::Scanner(UnicodeCache* unicode_cache)
40 : unicode_cache_(unicode_cache),
41 bookmark_c0_(kNoBookmark),
42 octal_pos_(Location::invalid()) {
43 bookmark_current_.literal_chars = &bookmark_current_literal_;
44 bookmark_current_.raw_literal_chars = &bookmark_current_raw_literal_;
45 bookmark_next_.literal_chars = &bookmark_next_literal_;
46 bookmark_next_.raw_literal_chars = &bookmark_next_raw_literal_;
47 }
48
49
Initialize(Utf16CharacterStream * source)50 void Scanner::Initialize(Utf16CharacterStream* source) {
51 source_ = source;
52 // Need to capture identifiers in order to recognize "get" and "set"
53 // in object literals.
54 Init();
55 // Skip initial whitespace allowing HTML comment ends just like
56 // after a newline and scan first token.
57 has_line_terminator_before_next_ = true;
58 SkipWhiteSpace();
59 Scan();
60 }
61
62
63 template <bool capture_raw>
ScanHexNumber(int expected_length)64 uc32 Scanner::ScanHexNumber(int expected_length) {
65 DCHECK(expected_length <= 4); // prevent overflow
66
67 uc32 x = 0;
68 for (int i = 0; i < expected_length; i++) {
69 int d = HexValue(c0_);
70 if (d < 0) {
71 return -1;
72 }
73 x = x * 16 + d;
74 Advance<capture_raw>();
75 }
76
77 return x;
78 }
79
80
81 template <bool capture_raw>
ScanUnlimitedLengthHexNumber(int max_value)82 uc32 Scanner::ScanUnlimitedLengthHexNumber(int max_value) {
83 uc32 x = 0;
84 int d = HexValue(c0_);
85 if (d < 0) {
86 return -1;
87 }
88 while (d >= 0) {
89 x = x * 16 + d;
90 if (x > max_value) return -1;
91 Advance<capture_raw>();
92 d = HexValue(c0_);
93 }
94 return x;
95 }
96
97
98 // Ensure that tokens can be stored in a byte.
99 STATIC_ASSERT(Token::NUM_TOKENS <= 0x100);
100
101 // Table of one-character tokens, by character (0x00..0x7f only).
102 static const byte one_char_tokens[] = {
103 Token::ILLEGAL,
104 Token::ILLEGAL,
105 Token::ILLEGAL,
106 Token::ILLEGAL,
107 Token::ILLEGAL,
108 Token::ILLEGAL,
109 Token::ILLEGAL,
110 Token::ILLEGAL,
111 Token::ILLEGAL,
112 Token::ILLEGAL,
113 Token::ILLEGAL,
114 Token::ILLEGAL,
115 Token::ILLEGAL,
116 Token::ILLEGAL,
117 Token::ILLEGAL,
118 Token::ILLEGAL,
119 Token::ILLEGAL,
120 Token::ILLEGAL,
121 Token::ILLEGAL,
122 Token::ILLEGAL,
123 Token::ILLEGAL,
124 Token::ILLEGAL,
125 Token::ILLEGAL,
126 Token::ILLEGAL,
127 Token::ILLEGAL,
128 Token::ILLEGAL,
129 Token::ILLEGAL,
130 Token::ILLEGAL,
131 Token::ILLEGAL,
132 Token::ILLEGAL,
133 Token::ILLEGAL,
134 Token::ILLEGAL,
135 Token::ILLEGAL,
136 Token::ILLEGAL,
137 Token::ILLEGAL,
138 Token::ILLEGAL,
139 Token::ILLEGAL,
140 Token::ILLEGAL,
141 Token::ILLEGAL,
142 Token::ILLEGAL,
143 Token::LPAREN, // 0x28
144 Token::RPAREN, // 0x29
145 Token::ILLEGAL,
146 Token::ILLEGAL,
147 Token::COMMA, // 0x2c
148 Token::ILLEGAL,
149 Token::ILLEGAL,
150 Token::ILLEGAL,
151 Token::ILLEGAL,
152 Token::ILLEGAL,
153 Token::ILLEGAL,
154 Token::ILLEGAL,
155 Token::ILLEGAL,
156 Token::ILLEGAL,
157 Token::ILLEGAL,
158 Token::ILLEGAL,
159 Token::ILLEGAL,
160 Token::ILLEGAL,
161 Token::COLON, // 0x3a
162 Token::SEMICOLON, // 0x3b
163 Token::ILLEGAL,
164 Token::ILLEGAL,
165 Token::ILLEGAL,
166 Token::CONDITIONAL, // 0x3f
167 Token::ILLEGAL,
168 Token::ILLEGAL,
169 Token::ILLEGAL,
170 Token::ILLEGAL,
171 Token::ILLEGAL,
172 Token::ILLEGAL,
173 Token::ILLEGAL,
174 Token::ILLEGAL,
175 Token::ILLEGAL,
176 Token::ILLEGAL,
177 Token::ILLEGAL,
178 Token::ILLEGAL,
179 Token::ILLEGAL,
180 Token::ILLEGAL,
181 Token::ILLEGAL,
182 Token::ILLEGAL,
183 Token::ILLEGAL,
184 Token::ILLEGAL,
185 Token::ILLEGAL,
186 Token::ILLEGAL,
187 Token::ILLEGAL,
188 Token::ILLEGAL,
189 Token::ILLEGAL,
190 Token::ILLEGAL,
191 Token::ILLEGAL,
192 Token::ILLEGAL,
193 Token::ILLEGAL,
194 Token::LBRACK, // 0x5b
195 Token::ILLEGAL,
196 Token::RBRACK, // 0x5d
197 Token::ILLEGAL,
198 Token::ILLEGAL,
199 Token::ILLEGAL,
200 Token::ILLEGAL,
201 Token::ILLEGAL,
202 Token::ILLEGAL,
203 Token::ILLEGAL,
204 Token::ILLEGAL,
205 Token::ILLEGAL,
206 Token::ILLEGAL,
207 Token::ILLEGAL,
208 Token::ILLEGAL,
209 Token::ILLEGAL,
210 Token::ILLEGAL,
211 Token::ILLEGAL,
212 Token::ILLEGAL,
213 Token::ILLEGAL,
214 Token::ILLEGAL,
215 Token::ILLEGAL,
216 Token::ILLEGAL,
217 Token::ILLEGAL,
218 Token::ILLEGAL,
219 Token::ILLEGAL,
220 Token::ILLEGAL,
221 Token::ILLEGAL,
222 Token::ILLEGAL,
223 Token::ILLEGAL,
224 Token::ILLEGAL,
225 Token::ILLEGAL,
226 Token::LBRACE, // 0x7b
227 Token::ILLEGAL,
228 Token::RBRACE, // 0x7d
229 Token::BIT_NOT, // 0x7e
230 Token::ILLEGAL
231 };
232
233
Next()234 Token::Value Scanner::Next() {
235 if (next_.token == Token::EOS) {
236 next_.location.beg_pos = current_.location.beg_pos;
237 next_.location.end_pos = current_.location.end_pos;
238 }
239 current_ = next_;
240 if (V8_UNLIKELY(next_next_.token != Token::UNINITIALIZED)) {
241 next_ = next_next_;
242 next_next_.token = Token::UNINITIALIZED;
243 return current_.token;
244 }
245 has_line_terminator_before_next_ = false;
246 has_multiline_comment_before_next_ = false;
247 if (static_cast<unsigned>(c0_) <= 0x7f) {
248 Token::Value token = static_cast<Token::Value>(one_char_tokens[c0_]);
249 if (token != Token::ILLEGAL) {
250 int pos = source_pos();
251 next_.token = token;
252 next_.location.beg_pos = pos;
253 next_.location.end_pos = pos + 1;
254 Advance();
255 return current_.token;
256 }
257 }
258 Scan();
259 return current_.token;
260 }
261
262
PeekAhead()263 Token::Value Scanner::PeekAhead() {
264 if (next_next_.token != Token::UNINITIALIZED) {
265 return next_next_.token;
266 }
267 TokenDesc prev = current_;
268 Next();
269 Token::Value ret = next_.token;
270 next_next_ = next_;
271 next_ = current_;
272 current_ = prev;
273 return ret;
274 }
275
276
277 // TODO(yangguo): check whether this is actually necessary.
IsLittleEndianByteOrderMark(uc32 c)278 static inline bool IsLittleEndianByteOrderMark(uc32 c) {
279 // The Unicode value U+FFFE is guaranteed never to be assigned as a
280 // Unicode character; this implies that in a Unicode context the
281 // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF
282 // character expressed in little-endian byte order (since it could
283 // not be a U+FFFE character expressed in big-endian byte
284 // order). Nevertheless, we check for it to be compatible with
285 // Spidermonkey.
286 return c == 0xFFFE;
287 }
288
289
SkipWhiteSpace()290 bool Scanner::SkipWhiteSpace() {
291 int start_position = source_pos();
292
293 while (true) {
294 while (true) {
295 // The unicode cache accepts unsigned inputs.
296 if (c0_ < 0) break;
297 // Advance as long as character is a WhiteSpace or LineTerminator.
298 // Remember if the latter is the case.
299 if (unicode_cache_->IsLineTerminator(c0_)) {
300 has_line_terminator_before_next_ = true;
301 } else if (!unicode_cache_->IsWhiteSpace(c0_) &&
302 !IsLittleEndianByteOrderMark(c0_)) {
303 break;
304 }
305 Advance();
306 }
307
308 // If there is an HTML comment end '-->' at the beginning of a
309 // line (with only whitespace in front of it), we treat the rest
310 // of the line as a comment. This is in line with the way
311 // SpiderMonkey handles it.
312 if (c0_ == '-' && has_line_terminator_before_next_) {
313 Advance();
314 if (c0_ == '-') {
315 Advance();
316 if (c0_ == '>') {
317 // Treat the rest of the line as a comment.
318 SkipSingleLineComment();
319 // Continue skipping white space after the comment.
320 continue;
321 }
322 PushBack('-'); // undo Advance()
323 }
324 PushBack('-'); // undo Advance()
325 }
326 // Return whether or not we skipped any characters.
327 return source_pos() != start_position;
328 }
329 }
330
331
SkipSingleLineComment()332 Token::Value Scanner::SkipSingleLineComment() {
333 Advance();
334
335 // The line terminator at the end of the line is not considered
336 // to be part of the single-line comment; it is recognized
337 // separately by the lexical grammar and becomes part of the
338 // stream of input elements for the syntactic grammar (see
339 // ECMA-262, section 7.4).
340 while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) {
341 Advance();
342 }
343
344 return Token::WHITESPACE;
345 }
346
347
SkipSourceURLComment()348 Token::Value Scanner::SkipSourceURLComment() {
349 TryToParseSourceURLComment();
350 while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) {
351 Advance();
352 }
353
354 return Token::WHITESPACE;
355 }
356
357
TryToParseSourceURLComment()358 void Scanner::TryToParseSourceURLComment() {
359 // Magic comments are of the form: //[#@]\s<name>=\s*<value>\s*.* and this
360 // function will just return if it cannot parse a magic comment.
361 if (c0_ < 0 || !unicode_cache_->IsWhiteSpace(c0_)) return;
362 Advance();
363 LiteralBuffer name;
364 while (c0_ >= 0 && !unicode_cache_->IsWhiteSpaceOrLineTerminator(c0_) &&
365 c0_ != '=') {
366 name.AddChar(c0_);
367 Advance();
368 }
369 if (!name.is_one_byte()) return;
370 Vector<const uint8_t> name_literal = name.one_byte_literal();
371 LiteralBuffer* value;
372 if (name_literal == STATIC_CHAR_VECTOR("sourceURL")) {
373 value = &source_url_;
374 } else if (name_literal == STATIC_CHAR_VECTOR("sourceMappingURL")) {
375 value = &source_mapping_url_;
376 } else {
377 return;
378 }
379 if (c0_ != '=')
380 return;
381 Advance();
382 value->Reset();
383 while (c0_ >= 0 && unicode_cache_->IsWhiteSpace(c0_)) {
384 Advance();
385 }
386 while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) {
387 // Disallowed characters.
388 if (c0_ == '"' || c0_ == '\'') {
389 value->Reset();
390 return;
391 }
392 if (unicode_cache_->IsWhiteSpace(c0_)) {
393 break;
394 }
395 value->AddChar(c0_);
396 Advance();
397 }
398 // Allow whitespace at the end.
399 while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) {
400 if (!unicode_cache_->IsWhiteSpace(c0_)) {
401 value->Reset();
402 break;
403 }
404 Advance();
405 }
406 }
407
408
SkipMultiLineComment()409 Token::Value Scanner::SkipMultiLineComment() {
410 DCHECK(c0_ == '*');
411 Advance();
412
413 while (c0_ >= 0) {
414 uc32 ch = c0_;
415 Advance();
416 if (c0_ >= 0 && unicode_cache_->IsLineTerminator(ch)) {
417 // Following ECMA-262, section 7.4, a comment containing
418 // a newline will make the comment count as a line-terminator.
419 has_multiline_comment_before_next_ = true;
420 }
421 // If we have reached the end of the multi-line comment, we
422 // consume the '/' and insert a whitespace. This way all
423 // multi-line comments are treated as whitespace.
424 if (ch == '*' && c0_ == '/') {
425 c0_ = ' ';
426 return Token::WHITESPACE;
427 }
428 }
429
430 // Unterminated multi-line comment.
431 return Token::ILLEGAL;
432 }
433
434
ScanHtmlComment()435 Token::Value Scanner::ScanHtmlComment() {
436 // Check for <!-- comments.
437 DCHECK(c0_ == '!');
438 Advance();
439 if (c0_ == '-') {
440 Advance();
441 if (c0_ == '-') return SkipSingleLineComment();
442 PushBack('-'); // undo Advance()
443 }
444 PushBack('!'); // undo Advance()
445 DCHECK(c0_ == '!');
446 return Token::LT;
447 }
448
449
Scan()450 void Scanner::Scan() {
451 next_.literal_chars = NULL;
452 next_.raw_literal_chars = NULL;
453 Token::Value token;
454 do {
455 // Remember the position of the next token
456 next_.location.beg_pos = source_pos();
457
458 switch (c0_) {
459 case ' ':
460 case '\t':
461 Advance();
462 token = Token::WHITESPACE;
463 break;
464
465 case '\n':
466 Advance();
467 has_line_terminator_before_next_ = true;
468 token = Token::WHITESPACE;
469 break;
470
471 case '"': case '\'':
472 token = ScanString();
473 break;
474
475 case '<':
476 // < <= << <<= <!--
477 Advance();
478 if (c0_ == '=') {
479 token = Select(Token::LTE);
480 } else if (c0_ == '<') {
481 token = Select('=', Token::ASSIGN_SHL, Token::SHL);
482 } else if (c0_ == '!') {
483 token = ScanHtmlComment();
484 } else {
485 token = Token::LT;
486 }
487 break;
488
489 case '>':
490 // > >= >> >>= >>> >>>=
491 Advance();
492 if (c0_ == '=') {
493 token = Select(Token::GTE);
494 } else if (c0_ == '>') {
495 // >> >>= >>> >>>=
496 Advance();
497 if (c0_ == '=') {
498 token = Select(Token::ASSIGN_SAR);
499 } else if (c0_ == '>') {
500 token = Select('=', Token::ASSIGN_SHR, Token::SHR);
501 } else {
502 token = Token::SAR;
503 }
504 } else {
505 token = Token::GT;
506 }
507 break;
508
509 case '=':
510 // = == === =>
511 Advance();
512 if (c0_ == '=') {
513 token = Select('=', Token::EQ_STRICT, Token::EQ);
514 } else if (c0_ == '>') {
515 token = Select(Token::ARROW);
516 } else {
517 token = Token::ASSIGN;
518 }
519 break;
520
521 case '!':
522 // ! != !==
523 Advance();
524 if (c0_ == '=') {
525 token = Select('=', Token::NE_STRICT, Token::NE);
526 } else {
527 token = Token::NOT;
528 }
529 break;
530
531 case '+':
532 // + ++ +=
533 Advance();
534 if (c0_ == '+') {
535 token = Select(Token::INC);
536 } else if (c0_ == '=') {
537 token = Select(Token::ASSIGN_ADD);
538 } else {
539 token = Token::ADD;
540 }
541 break;
542
543 case '-':
544 // - -- --> -=
545 Advance();
546 if (c0_ == '-') {
547 Advance();
548 if (c0_ == '>' && has_line_terminator_before_next_) {
549 // For compatibility with SpiderMonkey, we skip lines that
550 // start with an HTML comment end '-->'.
551 token = SkipSingleLineComment();
552 } else {
553 token = Token::DEC;
554 }
555 } else if (c0_ == '=') {
556 token = Select(Token::ASSIGN_SUB);
557 } else {
558 token = Token::SUB;
559 }
560 break;
561
562 case '*':
563 // * *=
564 token = Select('=', Token::ASSIGN_MUL, Token::MUL);
565 break;
566
567 case '%':
568 // % %=
569 token = Select('=', Token::ASSIGN_MOD, Token::MOD);
570 break;
571
572 case '/':
573 // / // /* /=
574 Advance();
575 if (c0_ == '/') {
576 Advance();
577 if (c0_ == '#' || c0_ == '@') {
578 Advance();
579 token = SkipSourceURLComment();
580 } else {
581 PushBack(c0_);
582 token = SkipSingleLineComment();
583 }
584 } else if (c0_ == '*') {
585 token = SkipMultiLineComment();
586 } else if (c0_ == '=') {
587 token = Select(Token::ASSIGN_DIV);
588 } else {
589 token = Token::DIV;
590 }
591 break;
592
593 case '&':
594 // & && &=
595 Advance();
596 if (c0_ == '&') {
597 token = Select(Token::AND);
598 } else if (c0_ == '=') {
599 token = Select(Token::ASSIGN_BIT_AND);
600 } else {
601 token = Token::BIT_AND;
602 }
603 break;
604
605 case '|':
606 // | || |=
607 Advance();
608 if (c0_ == '|') {
609 token = Select(Token::OR);
610 } else if (c0_ == '=') {
611 token = Select(Token::ASSIGN_BIT_OR);
612 } else {
613 token = Token::BIT_OR;
614 }
615 break;
616
617 case '^':
618 // ^ ^=
619 token = Select('=', Token::ASSIGN_BIT_XOR, Token::BIT_XOR);
620 break;
621
622 case '.':
623 // . Number
624 Advance();
625 if (IsDecimalDigit(c0_)) {
626 token = ScanNumber(true);
627 } else {
628 token = Token::PERIOD;
629 if (c0_ == '.') {
630 Advance();
631 if (c0_ == '.') {
632 Advance();
633 token = Token::ELLIPSIS;
634 } else {
635 PushBack('.');
636 }
637 }
638 }
639 break;
640
641 case ':':
642 token = Select(Token::COLON);
643 break;
644
645 case ';':
646 token = Select(Token::SEMICOLON);
647 break;
648
649 case ',':
650 token = Select(Token::COMMA);
651 break;
652
653 case '(':
654 token = Select(Token::LPAREN);
655 break;
656
657 case ')':
658 token = Select(Token::RPAREN);
659 break;
660
661 case '[':
662 token = Select(Token::LBRACK);
663 break;
664
665 case ']':
666 token = Select(Token::RBRACK);
667 break;
668
669 case '{':
670 token = Select(Token::LBRACE);
671 break;
672
673 case '}':
674 token = Select(Token::RBRACE);
675 break;
676
677 case '?':
678 token = Select(Token::CONDITIONAL);
679 break;
680
681 case '~':
682 token = Select(Token::BIT_NOT);
683 break;
684
685 case '`':
686 token = ScanTemplateStart();
687 break;
688
689 default:
690 if (c0_ < 0) {
691 token = Token::EOS;
692 } else if (unicode_cache_->IsIdentifierStart(c0_)) {
693 token = ScanIdentifierOrKeyword();
694 } else if (IsDecimalDigit(c0_)) {
695 token = ScanNumber(false);
696 } else if (SkipWhiteSpace()) {
697 token = Token::WHITESPACE;
698 } else {
699 token = Select(Token::ILLEGAL);
700 }
701 break;
702 }
703
704 // Continue scanning for tokens as long as we're just skipping
705 // whitespace.
706 } while (token == Token::WHITESPACE);
707
708 next_.location.end_pos = source_pos();
709 next_.token = token;
710 }
711
712
SeekForward(int pos)713 void Scanner::SeekForward(int pos) {
714 // After this call, we will have the token at the given position as
715 // the "next" token. The "current" token will be invalid.
716 if (pos == next_.location.beg_pos) return;
717 int current_pos = source_pos();
718 DCHECK_EQ(next_.location.end_pos, current_pos);
719 // Positions inside the lookahead token aren't supported.
720 DCHECK(pos >= current_pos);
721 if (pos != current_pos) {
722 source_->SeekForward(pos - source_->pos());
723 Advance();
724 // This function is only called to seek to the location
725 // of the end of a function (at the "}" token). It doesn't matter
726 // whether there was a line terminator in the part we skip.
727 has_line_terminator_before_next_ = false;
728 has_multiline_comment_before_next_ = false;
729 }
730 Scan();
731 }
732
733
734 template <bool capture_raw, bool in_template_literal>
ScanEscape()735 bool Scanner::ScanEscape() {
736 uc32 c = c0_;
737 Advance<capture_raw>();
738
739 // Skip escaped newlines.
740 if (!in_template_literal && c0_ >= 0 && unicode_cache_->IsLineTerminator(c)) {
741 // Allow CR+LF newlines in multiline string literals.
742 if (IsCarriageReturn(c) && IsLineFeed(c0_)) Advance<capture_raw>();
743 // Allow LF+CR newlines in multiline string literals.
744 if (IsLineFeed(c) && IsCarriageReturn(c0_)) Advance<capture_raw>();
745 return true;
746 }
747
748 switch (c) {
749 case '\'': // fall through
750 case '"' : // fall through
751 case '\\': break;
752 case 'b' : c = '\b'; break;
753 case 'f' : c = '\f'; break;
754 case 'n' : c = '\n'; break;
755 case 'r' : c = '\r'; break;
756 case 't' : c = '\t'; break;
757 case 'u' : {
758 c = ScanUnicodeEscape<capture_raw>();
759 if (c < 0) return false;
760 break;
761 }
762 case 'v':
763 c = '\v';
764 break;
765 case 'x': {
766 c = ScanHexNumber<capture_raw>(2);
767 if (c < 0) return false;
768 break;
769 }
770 case '0': // Fall through.
771 case '1': // fall through
772 case '2': // fall through
773 case '3': // fall through
774 case '4': // fall through
775 case '5': // fall through
776 case '6': // fall through
777 case '7':
778 c = ScanOctalEscape<capture_raw>(c, 2);
779 break;
780 }
781
782 // According to ECMA-262, section 7.8.4, characters not covered by the
783 // above cases should be illegal, but they are commonly handled as
784 // non-escaped characters by JS VMs.
785 AddLiteralChar(c);
786 return true;
787 }
788
789
790 // Octal escapes of the forms '\0xx' and '\xxx' are not a part of
791 // ECMA-262. Other JS VMs support them.
792 template <bool capture_raw>
ScanOctalEscape(uc32 c,int length)793 uc32 Scanner::ScanOctalEscape(uc32 c, int length) {
794 uc32 x = c - '0';
795 int i = 0;
796 for (; i < length; i++) {
797 int d = c0_ - '0';
798 if (d < 0 || d > 7) break;
799 int nx = x * 8 + d;
800 if (nx >= 256) break;
801 x = nx;
802 Advance<capture_raw>();
803 }
804 // Anything except '\0' is an octal escape sequence, illegal in strict mode.
805 // Remember the position of octal escape sequences so that an error
806 // can be reported later (in strict mode).
807 // We don't report the error immediately, because the octal escape can
808 // occur before the "use strict" directive.
809 if (c != '0' || i > 0) {
810 octal_pos_ = Location(source_pos() - i - 1, source_pos() - 1);
811 }
812 return x;
813 }
814
815
816 const int kMaxAscii = 127;
817
818
ScanString()819 Token::Value Scanner::ScanString() {
820 uc32 quote = c0_;
821 Advance<false, false>(); // consume quote
822
823 LiteralScope literal(this);
824 while (true) {
825 if (c0_ > kMaxAscii) {
826 HandleLeadSurrogate();
827 break;
828 }
829 if (c0_ < 0 || c0_ == '\n' || c0_ == '\r') return Token::ILLEGAL;
830 if (c0_ == quote) {
831 literal.Complete();
832 Advance<false, false>();
833 return Token::STRING;
834 }
835 uc32 c = c0_;
836 if (c == '\\') break;
837 Advance<false, false>();
838 AddLiteralChar(c);
839 }
840
841 while (c0_ != quote && c0_ >= 0
842 && !unicode_cache_->IsLineTerminator(c0_)) {
843 uc32 c = c0_;
844 Advance();
845 if (c == '\\') {
846 if (c0_ < 0 || !ScanEscape<false, false>()) return Token::ILLEGAL;
847 } else {
848 AddLiteralChar(c);
849 }
850 }
851 if (c0_ != quote) return Token::ILLEGAL;
852 literal.Complete();
853
854 Advance(); // consume quote
855 return Token::STRING;
856 }
857
858
ScanTemplateSpan()859 Token::Value Scanner::ScanTemplateSpan() {
860 // When scanning a TemplateSpan, we are looking for the following construct:
861 // TEMPLATE_SPAN ::
862 // ` LiteralChars* ${
863 // | } LiteralChars* ${
864 //
865 // TEMPLATE_TAIL ::
866 // ` LiteralChars* `
867 // | } LiteralChar* `
868 //
869 // A TEMPLATE_SPAN should always be followed by an Expression, while a
870 // TEMPLATE_TAIL terminates a TemplateLiteral and does not need to be
871 // followed by an Expression.
872
873 Token::Value result = Token::TEMPLATE_SPAN;
874 LiteralScope literal(this);
875 StartRawLiteral();
876 const bool capture_raw = true;
877 const bool in_template_literal = true;
878
879 while (true) {
880 uc32 c = c0_;
881 Advance<capture_raw>();
882 if (c == '`') {
883 result = Token::TEMPLATE_TAIL;
884 ReduceRawLiteralLength(1);
885 break;
886 } else if (c == '$' && c0_ == '{') {
887 Advance<capture_raw>(); // Consume '{'
888 ReduceRawLiteralLength(2);
889 break;
890 } else if (c == '\\') {
891 if (c0_ > 0 && unicode_cache_->IsLineTerminator(c0_)) {
892 // The TV of LineContinuation :: \ LineTerminatorSequence is the empty
893 // code unit sequence.
894 uc32 lastChar = c0_;
895 Advance<capture_raw>();
896 if (lastChar == '\r') {
897 ReduceRawLiteralLength(1); // Remove \r
898 if (c0_ == '\n') {
899 Advance<capture_raw>(); // Adds \n
900 } else {
901 AddRawLiteralChar('\n');
902 }
903 }
904 } else if (!ScanEscape<capture_raw, in_template_literal>()) {
905 return Token::ILLEGAL;
906 }
907 } else if (c < 0) {
908 // Unterminated template literal
909 PushBack(c);
910 break;
911 } else {
912 // The TRV of LineTerminatorSequence :: <CR> is the CV 0x000A.
913 // The TRV of LineTerminatorSequence :: <CR><LF> is the sequence
914 // consisting of the CV 0x000A.
915 if (c == '\r') {
916 ReduceRawLiteralLength(1); // Remove \r
917 if (c0_ == '\n') {
918 Advance<capture_raw>(); // Adds \n
919 } else {
920 AddRawLiteralChar('\n');
921 }
922 c = '\n';
923 }
924 AddLiteralChar(c);
925 }
926 }
927 literal.Complete();
928 next_.location.end_pos = source_pos();
929 next_.token = result;
930 return result;
931 }
932
933
ScanTemplateStart()934 Token::Value Scanner::ScanTemplateStart() {
935 DCHECK(c0_ == '`');
936 next_.location.beg_pos = source_pos();
937 Advance(); // Consume `
938 return ScanTemplateSpan();
939 }
940
941
ScanTemplateContinuation()942 Token::Value Scanner::ScanTemplateContinuation() {
943 DCHECK_EQ(next_.token, Token::RBRACE);
944 next_.location.beg_pos = source_pos() - 1; // We already consumed }
945 return ScanTemplateSpan();
946 }
947
948
ScanDecimalDigits()949 void Scanner::ScanDecimalDigits() {
950 while (IsDecimalDigit(c0_))
951 AddLiteralCharAdvance();
952 }
953
954
ScanNumber(bool seen_period)955 Token::Value Scanner::ScanNumber(bool seen_period) {
956 DCHECK(IsDecimalDigit(c0_)); // the first digit of the number or the fraction
957
958 enum { DECIMAL, HEX, OCTAL, IMPLICIT_OCTAL, BINARY } kind = DECIMAL;
959
960 LiteralScope literal(this);
961 bool at_start = !seen_period;
962 if (seen_period) {
963 // we have already seen a decimal point of the float
964 AddLiteralChar('.');
965 ScanDecimalDigits(); // we know we have at least one digit
966
967 } else {
968 // if the first character is '0' we must check for octals and hex
969 if (c0_ == '0') {
970 int start_pos = source_pos(); // For reporting octal positions.
971 AddLiteralCharAdvance();
972
973 // either 0, 0exxx, 0Exxx, 0.xxx, a hex number, a binary number or
974 // an octal number.
975 if (c0_ == 'x' || c0_ == 'X') {
976 // hex number
977 kind = HEX;
978 AddLiteralCharAdvance();
979 if (!IsHexDigit(c0_)) {
980 // we must have at least one hex digit after 'x'/'X'
981 return Token::ILLEGAL;
982 }
983 while (IsHexDigit(c0_)) {
984 AddLiteralCharAdvance();
985 }
986 } else if (c0_ == 'o' || c0_ == 'O') {
987 kind = OCTAL;
988 AddLiteralCharAdvance();
989 if (!IsOctalDigit(c0_)) {
990 // we must have at least one octal digit after 'o'/'O'
991 return Token::ILLEGAL;
992 }
993 while (IsOctalDigit(c0_)) {
994 AddLiteralCharAdvance();
995 }
996 } else if (c0_ == 'b' || c0_ == 'B') {
997 kind = BINARY;
998 AddLiteralCharAdvance();
999 if (!IsBinaryDigit(c0_)) {
1000 // we must have at least one binary digit after 'b'/'B'
1001 return Token::ILLEGAL;
1002 }
1003 while (IsBinaryDigit(c0_)) {
1004 AddLiteralCharAdvance();
1005 }
1006 } else if ('0' <= c0_ && c0_ <= '7') {
1007 // (possible) octal number
1008 kind = IMPLICIT_OCTAL;
1009 while (true) {
1010 if (c0_ == '8' || c0_ == '9') {
1011 at_start = false;
1012 kind = DECIMAL;
1013 break;
1014 }
1015 if (c0_ < '0' || '7' < c0_) {
1016 // Octal literal finished.
1017 octal_pos_ = Location(start_pos, source_pos());
1018 break;
1019 }
1020 AddLiteralCharAdvance();
1021 }
1022 }
1023 }
1024
1025 // Parse decimal digits and allow trailing fractional part.
1026 if (kind == DECIMAL) {
1027 if (at_start) {
1028 uint64_t value = 0;
1029 while (IsDecimalDigit(c0_)) {
1030 value = 10 * value + (c0_ - '0');
1031
1032 uc32 first_char = c0_;
1033 Advance<false, false>();
1034 AddLiteralChar(first_char);
1035 }
1036
1037 if (next_.literal_chars->one_byte_literal().length() <= 10 &&
1038 value <= Smi::kMaxValue && c0_ != '.' && c0_ != 'e' && c0_ != 'E') {
1039 next_.smi_value_ = static_cast<int>(value);
1040 literal.Complete();
1041 HandleLeadSurrogate();
1042
1043 return Token::SMI;
1044 }
1045 HandleLeadSurrogate();
1046 }
1047
1048 ScanDecimalDigits(); // optional
1049 if (c0_ == '.') {
1050 AddLiteralCharAdvance();
1051 ScanDecimalDigits(); // optional
1052 }
1053 }
1054 }
1055
1056 // scan exponent, if any
1057 if (c0_ == 'e' || c0_ == 'E') {
1058 DCHECK(kind != HEX); // 'e'/'E' must be scanned as part of the hex number
1059 if (kind != DECIMAL) return Token::ILLEGAL;
1060 // scan exponent
1061 AddLiteralCharAdvance();
1062 if (c0_ == '+' || c0_ == '-')
1063 AddLiteralCharAdvance();
1064 if (!IsDecimalDigit(c0_)) {
1065 // we must have at least one decimal digit after 'e'/'E'
1066 return Token::ILLEGAL;
1067 }
1068 ScanDecimalDigits();
1069 }
1070
1071 // The source character immediately following a numeric literal must
1072 // not be an identifier start or a decimal digit; see ECMA-262
1073 // section 7.8.3, page 17 (note that we read only one decimal digit
1074 // if the value is 0).
1075 if (IsDecimalDigit(c0_) ||
1076 (c0_ >= 0 && unicode_cache_->IsIdentifierStart(c0_)))
1077 return Token::ILLEGAL;
1078
1079 literal.Complete();
1080
1081 return Token::NUMBER;
1082 }
1083
1084
ScanIdentifierUnicodeEscape()1085 uc32 Scanner::ScanIdentifierUnicodeEscape() {
1086 Advance();
1087 if (c0_ != 'u') return -1;
1088 Advance();
1089 return ScanUnicodeEscape<false>();
1090 }
1091
1092
1093 template <bool capture_raw>
ScanUnicodeEscape()1094 uc32 Scanner::ScanUnicodeEscape() {
1095 // Accept both \uxxxx and \u{xxxxxx}. In the latter case, the number of
1096 // hex digits between { } is arbitrary. \ and u have already been read.
1097 if (c0_ == '{') {
1098 Advance<capture_raw>();
1099 uc32 cp = ScanUnlimitedLengthHexNumber<capture_raw>(0x10ffff);
1100 if (cp < 0) {
1101 return -1;
1102 }
1103 if (c0_ != '}') {
1104 return -1;
1105 }
1106 Advance<capture_raw>();
1107 return cp;
1108 }
1109 return ScanHexNumber<capture_raw>(4);
1110 }
1111
1112
1113 // ----------------------------------------------------------------------------
1114 // Keyword Matcher
1115
1116 #define KEYWORDS(KEYWORD_GROUP, KEYWORD) \
1117 KEYWORD_GROUP('b') \
1118 KEYWORD("break", Token::BREAK) \
1119 KEYWORD_GROUP('c') \
1120 KEYWORD("case", Token::CASE) \
1121 KEYWORD("catch", Token::CATCH) \
1122 KEYWORD("class", Token::CLASS) \
1123 KEYWORD("const", Token::CONST) \
1124 KEYWORD("continue", Token::CONTINUE) \
1125 KEYWORD_GROUP('d') \
1126 KEYWORD("debugger", Token::DEBUGGER) \
1127 KEYWORD("default", Token::DEFAULT) \
1128 KEYWORD("delete", Token::DELETE) \
1129 KEYWORD("do", Token::DO) \
1130 KEYWORD_GROUP('e') \
1131 KEYWORD("else", Token::ELSE) \
1132 KEYWORD("enum", Token::FUTURE_RESERVED_WORD) \
1133 KEYWORD("export", Token::EXPORT) \
1134 KEYWORD("extends", Token::EXTENDS) \
1135 KEYWORD_GROUP('f') \
1136 KEYWORD("false", Token::FALSE_LITERAL) \
1137 KEYWORD("finally", Token::FINALLY) \
1138 KEYWORD("for", Token::FOR) \
1139 KEYWORD("function", Token::FUNCTION) \
1140 KEYWORD_GROUP('i') \
1141 KEYWORD("if", Token::IF) \
1142 KEYWORD("implements", Token::FUTURE_STRICT_RESERVED_WORD) \
1143 KEYWORD("import", Token::IMPORT) \
1144 KEYWORD("in", Token::IN) \
1145 KEYWORD("instanceof", Token::INSTANCEOF) \
1146 KEYWORD("interface", Token::FUTURE_STRICT_RESERVED_WORD) \
1147 KEYWORD_GROUP('l') \
1148 KEYWORD("let", Token::LET) \
1149 KEYWORD_GROUP('n') \
1150 KEYWORD("new", Token::NEW) \
1151 KEYWORD("null", Token::NULL_LITERAL) \
1152 KEYWORD_GROUP('p') \
1153 KEYWORD("package", Token::FUTURE_STRICT_RESERVED_WORD) \
1154 KEYWORD("private", Token::FUTURE_STRICT_RESERVED_WORD) \
1155 KEYWORD("protected", Token::FUTURE_STRICT_RESERVED_WORD) \
1156 KEYWORD("public", Token::FUTURE_STRICT_RESERVED_WORD) \
1157 KEYWORD_GROUP('r') \
1158 KEYWORD("return", Token::RETURN) \
1159 KEYWORD_GROUP('s') \
1160 KEYWORD("static", Token::STATIC) \
1161 KEYWORD("super", Token::SUPER) \
1162 KEYWORD("switch", Token::SWITCH) \
1163 KEYWORD_GROUP('t') \
1164 KEYWORD("this", Token::THIS) \
1165 KEYWORD("throw", Token::THROW) \
1166 KEYWORD("true", Token::TRUE_LITERAL) \
1167 KEYWORD("try", Token::TRY) \
1168 KEYWORD("typeof", Token::TYPEOF) \
1169 KEYWORD_GROUP('v') \
1170 KEYWORD("var", Token::VAR) \
1171 KEYWORD("void", Token::VOID) \
1172 KEYWORD_GROUP('w') \
1173 KEYWORD("while", Token::WHILE) \
1174 KEYWORD("with", Token::WITH) \
1175 KEYWORD_GROUP('y') \
1176 KEYWORD("yield", Token::YIELD)
1177
1178
KeywordOrIdentifierToken(const uint8_t * input,int input_length,bool escaped)1179 static Token::Value KeywordOrIdentifierToken(const uint8_t* input,
1180 int input_length, bool escaped) {
1181 DCHECK(input_length >= 1);
1182 const int kMinLength = 2;
1183 const int kMaxLength = 10;
1184 if (input_length < kMinLength || input_length > kMaxLength) {
1185 return Token::IDENTIFIER;
1186 }
1187 switch (input[0]) {
1188 default:
1189 #define KEYWORD_GROUP_CASE(ch) \
1190 break; \
1191 case ch:
1192 #define KEYWORD(keyword, token) \
1193 { \
1194 /* 'keyword' is a char array, so sizeof(keyword) is */ \
1195 /* strlen(keyword) plus 1 for the NUL char. */ \
1196 const int keyword_length = sizeof(keyword) - 1; \
1197 STATIC_ASSERT(keyword_length >= kMinLength); \
1198 STATIC_ASSERT(keyword_length <= kMaxLength); \
1199 if (input_length == keyword_length && input[1] == keyword[1] && \
1200 (keyword_length <= 2 || input[2] == keyword[2]) && \
1201 (keyword_length <= 3 || input[3] == keyword[3]) && \
1202 (keyword_length <= 4 || input[4] == keyword[4]) && \
1203 (keyword_length <= 5 || input[5] == keyword[5]) && \
1204 (keyword_length <= 6 || input[6] == keyword[6]) && \
1205 (keyword_length <= 7 || input[7] == keyword[7]) && \
1206 (keyword_length <= 8 || input[8] == keyword[8]) && \
1207 (keyword_length <= 9 || input[9] == keyword[9])) { \
1208 if (escaped) { \
1209 return token == Token::FUTURE_STRICT_RESERVED_WORD \
1210 ? Token::ESCAPED_STRICT_RESERVED_WORD \
1211 : Token::ESCAPED_KEYWORD; \
1212 } \
1213 return token; \
1214 } \
1215 }
1216 KEYWORDS(KEYWORD_GROUP_CASE, KEYWORD)
1217 }
1218 return Token::IDENTIFIER;
1219 }
1220
1221
IdentifierIsFutureStrictReserved(const AstRawString * string) const1222 bool Scanner::IdentifierIsFutureStrictReserved(
1223 const AstRawString* string) const {
1224 // Keywords are always 1-byte strings.
1225 if (!string->is_one_byte()) return false;
1226 if (string->IsOneByteEqualTo("let") || string->IsOneByteEqualTo("static") ||
1227 string->IsOneByteEqualTo("yield")) {
1228 return true;
1229 }
1230 return Token::FUTURE_STRICT_RESERVED_WORD ==
1231 KeywordOrIdentifierToken(string->raw_data(), string->length(), false);
1232 }
1233
1234
ScanIdentifierOrKeyword()1235 Token::Value Scanner::ScanIdentifierOrKeyword() {
1236 DCHECK(unicode_cache_->IsIdentifierStart(c0_));
1237 LiteralScope literal(this);
1238 if (IsInRange(c0_, 'a', 'z')) {
1239 do {
1240 uc32 first_char = c0_;
1241 Advance<false, false>();
1242 AddLiteralChar(first_char);
1243 } while (IsInRange(c0_, 'a', 'z'));
1244
1245 if (IsDecimalDigit(c0_) || IsInRange(c0_, 'A', 'Z') || c0_ == '_' ||
1246 c0_ == '$') {
1247 // Identifier starting with lowercase.
1248 uc32 first_char = c0_;
1249 Advance<false, false>();
1250 AddLiteralChar(first_char);
1251 while (IsAsciiIdentifier(c0_)) {
1252 uc32 first_char = c0_;
1253 Advance<false, false>();
1254 AddLiteralChar(first_char);
1255 }
1256 if (c0_ <= kMaxAscii && c0_ != '\\') {
1257 literal.Complete();
1258 return Token::IDENTIFIER;
1259 }
1260 } else if (c0_ <= kMaxAscii && c0_ != '\\') {
1261 // Only a-z+: could be a keyword or identifier.
1262 literal.Complete();
1263 Vector<const uint8_t> chars = next_.literal_chars->one_byte_literal();
1264 return KeywordOrIdentifierToken(chars.start(), chars.length(), false);
1265 }
1266
1267 HandleLeadSurrogate();
1268 } else if (IsInRange(c0_, 'A', 'Z') || c0_ == '_' || c0_ == '$') {
1269 do {
1270 uc32 first_char = c0_;
1271 Advance<false, false>();
1272 AddLiteralChar(first_char);
1273 } while (IsAsciiIdentifier(c0_));
1274
1275 if (c0_ <= kMaxAscii && c0_ != '\\') {
1276 literal.Complete();
1277 return Token::IDENTIFIER;
1278 }
1279
1280 HandleLeadSurrogate();
1281 } else if (c0_ == '\\') {
1282 // Scan identifier start character.
1283 uc32 c = ScanIdentifierUnicodeEscape();
1284 // Only allow legal identifier start characters.
1285 if (c < 0 ||
1286 c == '\\' || // No recursive escapes.
1287 !unicode_cache_->IsIdentifierStart(c)) {
1288 return Token::ILLEGAL;
1289 }
1290 AddLiteralChar(c);
1291 return ScanIdentifierSuffix(&literal, true);
1292 } else {
1293 uc32 first_char = c0_;
1294 Advance();
1295 AddLiteralChar(first_char);
1296 }
1297
1298 // Scan the rest of the identifier characters.
1299 while (c0_ >= 0 && unicode_cache_->IsIdentifierPart(c0_)) {
1300 if (c0_ != '\\') {
1301 uc32 next_char = c0_;
1302 Advance();
1303 AddLiteralChar(next_char);
1304 continue;
1305 }
1306 // Fallthrough if no longer able to complete keyword.
1307 return ScanIdentifierSuffix(&literal, false);
1308 }
1309
1310 literal.Complete();
1311
1312 if (next_.literal_chars->is_one_byte()) {
1313 Vector<const uint8_t> chars = next_.literal_chars->one_byte_literal();
1314 return KeywordOrIdentifierToken(chars.start(), chars.length(), false);
1315 }
1316 return Token::IDENTIFIER;
1317 }
1318
1319
ScanIdentifierSuffix(LiteralScope * literal,bool escaped)1320 Token::Value Scanner::ScanIdentifierSuffix(LiteralScope* literal,
1321 bool escaped) {
1322 // Scan the rest of the identifier characters.
1323 while (c0_ >= 0 && unicode_cache_->IsIdentifierPart(c0_)) {
1324 if (c0_ == '\\') {
1325 uc32 c = ScanIdentifierUnicodeEscape();
1326 escaped = true;
1327 // Only allow legal identifier part characters.
1328 if (c < 0 ||
1329 c == '\\' ||
1330 !unicode_cache_->IsIdentifierPart(c)) {
1331 return Token::ILLEGAL;
1332 }
1333 AddLiteralChar(c);
1334 } else {
1335 AddLiteralChar(c0_);
1336 Advance();
1337 }
1338 }
1339 literal->Complete();
1340
1341 if (escaped && next_.literal_chars->is_one_byte()) {
1342 Vector<const uint8_t> chars = next_.literal_chars->one_byte_literal();
1343 return KeywordOrIdentifierToken(chars.start(), chars.length(), true);
1344 }
1345 return Token::IDENTIFIER;
1346 }
1347
1348
ScanRegExpPattern(bool seen_equal)1349 bool Scanner::ScanRegExpPattern(bool seen_equal) {
1350 // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags
1351 bool in_character_class = false;
1352
1353 // Previous token is either '/' or '/=', in the second case, the
1354 // pattern starts at =.
1355 next_.location.beg_pos = source_pos() - (seen_equal ? 2 : 1);
1356 next_.location.end_pos = source_pos() - (seen_equal ? 1 : 0);
1357
1358 // Scan regular expression body: According to ECMA-262, 3rd, 7.8.5,
1359 // the scanner should pass uninterpreted bodies to the RegExp
1360 // constructor.
1361 LiteralScope literal(this);
1362 if (seen_equal) {
1363 AddLiteralChar('=');
1364 }
1365
1366 while (c0_ != '/' || in_character_class) {
1367 if (c0_ < 0 || unicode_cache_->IsLineTerminator(c0_)) return false;
1368 if (c0_ == '\\') { // Escape sequence.
1369 AddLiteralCharAdvance();
1370 if (c0_ < 0 || unicode_cache_->IsLineTerminator(c0_)) return false;
1371 AddLiteralCharAdvance();
1372 // If the escape allows more characters, i.e., \x??, \u????, or \c?,
1373 // only "safe" characters are allowed (letters, digits, underscore),
1374 // otherwise the escape isn't valid and the invalid character has
1375 // its normal meaning. I.e., we can just continue scanning without
1376 // worrying whether the following characters are part of the escape
1377 // or not, since any '/', '\\' or '[' is guaranteed to not be part
1378 // of the escape sequence.
1379
1380 // TODO(896): At some point, parse RegExps more throughly to capture
1381 // octal esacpes in strict mode.
1382 } else { // Unescaped character.
1383 if (c0_ == '[') in_character_class = true;
1384 if (c0_ == ']') in_character_class = false;
1385 AddLiteralCharAdvance();
1386 }
1387 }
1388 Advance(); // consume '/'
1389
1390 literal.Complete();
1391
1392 return true;
1393 }
1394
1395
ScanRegExpFlags()1396 Maybe<RegExp::Flags> Scanner::ScanRegExpFlags() {
1397 // Scan regular expression flags.
1398 LiteralScope literal(this);
1399 int flags = 0;
1400 while (c0_ >= 0 && unicode_cache_->IsIdentifierPart(c0_)) {
1401 RegExp::Flags flag = RegExp::kNone;
1402 switch (c0_) {
1403 case 'g':
1404 flag = RegExp::kGlobal;
1405 break;
1406 case 'i':
1407 flag = RegExp::kIgnoreCase;
1408 break;
1409 case 'm':
1410 flag = RegExp::kMultiline;
1411 break;
1412 case 'u':
1413 if (!FLAG_harmony_unicode_regexps) return Nothing<RegExp::Flags>();
1414 flag = RegExp::kUnicode;
1415 break;
1416 case 'y':
1417 if (!FLAG_harmony_regexps) return Nothing<RegExp::Flags>();
1418 flag = RegExp::kSticky;
1419 break;
1420 default:
1421 return Nothing<RegExp::Flags>();
1422 }
1423 if (flags & flag) return Nothing<RegExp::Flags>();
1424 AddLiteralCharAdvance();
1425 flags |= flag;
1426 }
1427 literal.Complete();
1428
1429 next_.location.end_pos = source_pos();
1430 return Just(RegExp::Flags(flags));
1431 }
1432
1433
CurrentSymbol(AstValueFactory * ast_value_factory)1434 const AstRawString* Scanner::CurrentSymbol(AstValueFactory* ast_value_factory) {
1435 if (is_literal_one_byte()) {
1436 return ast_value_factory->GetOneByteString(literal_one_byte_string());
1437 }
1438 return ast_value_factory->GetTwoByteString(literal_two_byte_string());
1439 }
1440
1441
NextSymbol(AstValueFactory * ast_value_factory)1442 const AstRawString* Scanner::NextSymbol(AstValueFactory* ast_value_factory) {
1443 if (is_next_literal_one_byte()) {
1444 return ast_value_factory->GetOneByteString(next_literal_one_byte_string());
1445 }
1446 return ast_value_factory->GetTwoByteString(next_literal_two_byte_string());
1447 }
1448
1449
CurrentRawSymbol(AstValueFactory * ast_value_factory)1450 const AstRawString* Scanner::CurrentRawSymbol(
1451 AstValueFactory* ast_value_factory) {
1452 if (is_raw_literal_one_byte()) {
1453 return ast_value_factory->GetOneByteString(raw_literal_one_byte_string());
1454 }
1455 return ast_value_factory->GetTwoByteString(raw_literal_two_byte_string());
1456 }
1457
1458
DoubleValue()1459 double Scanner::DoubleValue() {
1460 DCHECK(is_literal_one_byte());
1461 return StringToDouble(
1462 unicode_cache_,
1463 literal_one_byte_string(),
1464 ALLOW_HEX | ALLOW_OCTAL | ALLOW_IMPLICIT_OCTAL | ALLOW_BINARY);
1465 }
1466
1467
ContainsDot()1468 bool Scanner::ContainsDot() {
1469 DCHECK(is_literal_one_byte());
1470 Vector<const uint8_t> str = literal_one_byte_string();
1471 return std::find(str.begin(), str.end(), '.') != str.end();
1472 }
1473
1474
FindSymbol(DuplicateFinder * finder,int value)1475 int Scanner::FindSymbol(DuplicateFinder* finder, int value) {
1476 if (is_literal_one_byte()) {
1477 return finder->AddOneByteSymbol(literal_one_byte_string(), value);
1478 }
1479 return finder->AddTwoByteSymbol(literal_two_byte_string(), value);
1480 }
1481
1482
SetBookmark()1483 bool Scanner::SetBookmark() {
1484 if (c0_ != kNoBookmark && bookmark_c0_ == kNoBookmark &&
1485 next_next_.token == Token::UNINITIALIZED && source_->SetBookmark()) {
1486 bookmark_c0_ = c0_;
1487 CopyTokenDesc(&bookmark_current_, ¤t_);
1488 CopyTokenDesc(&bookmark_next_, &next_);
1489 return true;
1490 }
1491 return false;
1492 }
1493
1494
ResetToBookmark()1495 void Scanner::ResetToBookmark() {
1496 DCHECK(BookmarkHasBeenSet()); // Caller hasn't called SetBookmark.
1497
1498 source_->ResetToBookmark();
1499 c0_ = bookmark_c0_;
1500 StartLiteral();
1501 StartRawLiteral();
1502 CopyTokenDesc(&next_, &bookmark_current_);
1503 current_ = next_;
1504 StartLiteral();
1505 StartRawLiteral();
1506 CopyTokenDesc(&next_, &bookmark_next_);
1507
1508 bookmark_c0_ = kBookmarkWasApplied;
1509 }
1510
1511
BookmarkHasBeenSet()1512 bool Scanner::BookmarkHasBeenSet() { return bookmark_c0_ >= 0; }
1513
1514
BookmarkHasBeenReset()1515 bool Scanner::BookmarkHasBeenReset() {
1516 return bookmark_c0_ == kBookmarkWasApplied;
1517 }
1518
1519
DropBookmark()1520 void Scanner::DropBookmark() { bookmark_c0_ = kNoBookmark; }
1521
1522
CopyTokenDesc(TokenDesc * to,TokenDesc * from)1523 void Scanner::CopyTokenDesc(TokenDesc* to, TokenDesc* from) {
1524 DCHECK_NOT_NULL(to);
1525 DCHECK_NOT_NULL(from);
1526 to->token = from->token;
1527 to->location = from->location;
1528 to->literal_chars->CopyFrom(from->literal_chars);
1529 to->raw_literal_chars->CopyFrom(from->raw_literal_chars);
1530 }
1531
1532
AddOneByteSymbol(Vector<const uint8_t> key,int value)1533 int DuplicateFinder::AddOneByteSymbol(Vector<const uint8_t> key, int value) {
1534 return AddSymbol(key, true, value);
1535 }
1536
1537
AddTwoByteSymbol(Vector<const uint16_t> key,int value)1538 int DuplicateFinder::AddTwoByteSymbol(Vector<const uint16_t> key, int value) {
1539 return AddSymbol(Vector<const uint8_t>::cast(key), false, value);
1540 }
1541
1542
AddSymbol(Vector<const uint8_t> key,bool is_one_byte,int value)1543 int DuplicateFinder::AddSymbol(Vector<const uint8_t> key,
1544 bool is_one_byte,
1545 int value) {
1546 uint32_t hash = Hash(key, is_one_byte);
1547 byte* encoding = BackupKey(key, is_one_byte);
1548 HashMap::Entry* entry = map_.LookupOrInsert(encoding, hash);
1549 int old_value = static_cast<int>(reinterpret_cast<intptr_t>(entry->value));
1550 entry->value =
1551 reinterpret_cast<void*>(static_cast<intptr_t>(value | old_value));
1552 return old_value;
1553 }
1554
1555
AddNumber(Vector<const uint8_t> key,int value)1556 int DuplicateFinder::AddNumber(Vector<const uint8_t> key, int value) {
1557 DCHECK(key.length() > 0);
1558 // Quick check for already being in canonical form.
1559 if (IsNumberCanonical(key)) {
1560 return AddOneByteSymbol(key, value);
1561 }
1562
1563 int flags = ALLOW_HEX | ALLOW_OCTAL | ALLOW_IMPLICIT_OCTAL | ALLOW_BINARY;
1564 double double_value = StringToDouble(
1565 unicode_constants_, key, flags, 0.0);
1566 int length;
1567 const char* string;
1568 if (!std::isfinite(double_value)) {
1569 string = "Infinity";
1570 length = 8; // strlen("Infinity");
1571 } else {
1572 string = DoubleToCString(double_value,
1573 Vector<char>(number_buffer_, kBufferSize));
1574 length = StrLength(string);
1575 }
1576 return AddSymbol(Vector<const byte>(reinterpret_cast<const byte*>(string),
1577 length), true, value);
1578 }
1579
1580
IsNumberCanonical(Vector<const uint8_t> number)1581 bool DuplicateFinder::IsNumberCanonical(Vector<const uint8_t> number) {
1582 // Test for a safe approximation of number literals that are already
1583 // in canonical form: max 15 digits, no leading zeroes, except an
1584 // integer part that is a single zero, and no trailing zeros below
1585 // the decimal point.
1586 int pos = 0;
1587 int length = number.length();
1588 if (number.length() > 15) return false;
1589 if (number[pos] == '0') {
1590 pos++;
1591 } else {
1592 while (pos < length &&
1593 static_cast<unsigned>(number[pos] - '0') <= ('9' - '0')) pos++;
1594 }
1595 if (length == pos) return true;
1596 if (number[pos] != '.') return false;
1597 pos++;
1598 bool invalid_last_digit = true;
1599 while (pos < length) {
1600 uint8_t digit = number[pos] - '0';
1601 if (digit > '9' - '0') return false;
1602 invalid_last_digit = (digit == 0);
1603 pos++;
1604 }
1605 return !invalid_last_digit;
1606 }
1607
1608
Hash(Vector<const uint8_t> key,bool is_one_byte)1609 uint32_t DuplicateFinder::Hash(Vector<const uint8_t> key, bool is_one_byte) {
1610 // Primitive hash function, almost identical to the one used
1611 // for strings (except that it's seeded by the length and representation).
1612 int length = key.length();
1613 uint32_t hash = (length << 1) | (is_one_byte ? 1 : 0);
1614 for (int i = 0; i < length; i++) {
1615 uint32_t c = key[i];
1616 hash = (hash + c) * 1025;
1617 hash ^= (hash >> 6);
1618 }
1619 return hash;
1620 }
1621
1622
Match(void * first,void * second)1623 bool DuplicateFinder::Match(void* first, void* second) {
1624 // Decode lengths.
1625 // Length + representation is encoded as base 128, most significant heptet
1626 // first, with a 8th bit being non-zero while there are more heptets.
1627 // The value encodes the number of bytes following, and whether the original
1628 // was Latin1.
1629 byte* s1 = reinterpret_cast<byte*>(first);
1630 byte* s2 = reinterpret_cast<byte*>(second);
1631 uint32_t length_one_byte_field = 0;
1632 byte c1;
1633 do {
1634 c1 = *s1;
1635 if (c1 != *s2) return false;
1636 length_one_byte_field = (length_one_byte_field << 7) | (c1 & 0x7f);
1637 s1++;
1638 s2++;
1639 } while ((c1 & 0x80) != 0);
1640 int length = static_cast<int>(length_one_byte_field >> 1);
1641 return memcmp(s1, s2, length) == 0;
1642 }
1643
1644
BackupKey(Vector<const uint8_t> bytes,bool is_one_byte)1645 byte* DuplicateFinder::BackupKey(Vector<const uint8_t> bytes,
1646 bool is_one_byte) {
1647 uint32_t one_byte_length = (bytes.length() << 1) | (is_one_byte ? 1 : 0);
1648 backing_store_.StartSequence();
1649 // Emit one_byte_length as base-128 encoded number, with the 7th bit set
1650 // on the byte of every heptet except the last, least significant, one.
1651 if (one_byte_length >= (1 << 7)) {
1652 if (one_byte_length >= (1 << 14)) {
1653 if (one_byte_length >= (1 << 21)) {
1654 if (one_byte_length >= (1 << 28)) {
1655 backing_store_.Add(
1656 static_cast<uint8_t>((one_byte_length >> 28) | 0x80));
1657 }
1658 backing_store_.Add(
1659 static_cast<uint8_t>((one_byte_length >> 21) | 0x80u));
1660 }
1661 backing_store_.Add(
1662 static_cast<uint8_t>((one_byte_length >> 14) | 0x80u));
1663 }
1664 backing_store_.Add(static_cast<uint8_t>((one_byte_length >> 7) | 0x80u));
1665 }
1666 backing_store_.Add(static_cast<uint8_t>(one_byte_length & 0x7f));
1667
1668 backing_store_.AddBlock(bytes);
1669 return backing_store_.EndSequence().start();
1670 }
1671
1672 } // namespace internal
1673 } // namespace v8
1674