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 23 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. 32 bool Utf16CharacterStream::SetBookmark() { return false; } 33 void Utf16CharacterStream::ResetToBookmark() { UNREACHABLE(); } 34 35 36 // ---------------------------------------------------------------------------- 37 // Scanner 38 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 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> 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> 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 }; 232 233 234 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 } 261 262 263 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. 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 } 288 289 290 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 } 330 331 332 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 } 346 347 348 Token::Value Scanner::SkipSourceURLComment() { 349 TryToParseSourceURLComment(); 350 while (c0_ >= 0 && !unicode_cache_->IsLineTerminator(c0_)) { 351 Advance(); 352 } 353 354 return Token::WHITESPACE; 355 } 356 357 358 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 } 407 408 409 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 } 433 434 435 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 } 448 449 450 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 } 711 712 713 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> 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> 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; 817 818 819 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 } 857 858 859 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 } 932 933 934 Token::Value Scanner::ScanTemplateStart() { 935 DCHECK(c0_ == '`'); 936 next_.location.beg_pos = source_pos(); 937 Advance(); // Consume ` 938 return ScanTemplateSpan(); 939 } 940 941 942 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 } 947 948 949 void Scanner::ScanDecimalDigits() { 950 while (IsDecimalDigit(c0_)) 951 AddLiteralCharAdvance(); 952 } 953 954 955 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 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> 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 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 1222 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 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 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 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 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 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 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 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 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 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 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 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 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 1512 bool Scanner::BookmarkHasBeenSet() { return bookmark_c0_ >= 0; } 1513 1514 1515 bool Scanner::BookmarkHasBeenReset() { 1516 return bookmark_c0_ == kBookmarkWasApplied; 1517 } 1518 1519 1520 void Scanner::DropBookmark() { bookmark_c0_ = kNoBookmark; } 1521 1522 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 1533 int DuplicateFinder::AddOneByteSymbol(Vector<const uint8_t> key, int value) { 1534 return AddSymbol(key, true, value); 1535 } 1536 1537 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 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 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 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 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 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 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
