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| 1 // Copyright 2010 the V8 project authors. All rights reserved. | |
| 2 // Redistribution and use in source and binary forms, with or without | |
| 3 // modification, are permitted provided that the following conditions are | |
| 4 // met: | |
| 5 // | |
| 6 // * Redistributions of source code must retain the above copyright | |
| 7 // notice, this list of conditions and the following disclaimer. | |
| 8 // * Redistributions in binary form must reproduce the above | |
| 9 // copyright notice, this list of conditions and the following | |
| 10 // disclaimer in the documentation and/or other materials provided | |
| 11 // with the distribution. | |
| 12 // * Neither the name of Google Inc. nor the names of its | |
| 13 // contributors may be used to endorse or promote products derived | |
| 14 // from this software without specific prior written permission. | |
| 15 // | |
| 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 | |
| 28 #ifndef V8_PRESCANNER_H_ | |
| 29 #define V8_PRESCANNER_H_ | |
| 30 | |
| 31 #include "token.h" | |
| 32 #include "char-predicates-inl.h" | |
| 33 #include "utils.h" | |
| 34 #include "scanner-base.h" | |
| 35 | |
| 36 namespace v8 { | |
| 37 namespace preparser { | |
| 38 | |
| 39 namespace i = v8::internal; | |
| 40 | |
| 41 typedef int uc32; | |
| 42 | |
| 43 class PreScannerStackGuard { | |
| 44 public: | |
| 45 explicit PreScannerStackGuard(int max_size) | |
| 46 : limit_(StackPoint().at() - max_size) { } | |
| 47 bool has_overflowed() { | |
| 48 return StackPoint().at() < limit_; | |
| 49 } | |
| 50 private: | |
| 51 class StackPoint { | |
| 52 public: | |
| 53 char* at() { return reinterpret_cast<char*>(this); } | |
| 54 }; | |
| 55 char* limit_; | |
| 56 }; | |
| 57 | |
| 58 | |
| 59 // Scanner for preparsing. | |
| 60 // InputStream is a source of UC16 characters with limited push-back. | |
| 61 // LiteralsBuffer is a collector of (UTF-8) characters used to capture literals. | |
| 62 class Scanner { | |
| 63 public: | |
| 64 enum LiteralType { | |
| 65 kLiteralNumber, | |
| 66 kLiteralIdentifier, | |
| 67 kLiteralString, | |
| 68 kLiteralRegExp, | |
| 69 kLiteralRegExpFlags | |
| 70 }; | |
| 71 | |
| 72 class LiteralScope { | |
| 73 public: | |
| 74 explicit LiteralScope(Scanner* self, LiteralType type); | |
| 75 ~LiteralScope(); | |
| 76 void Complete(); | |
| 77 | |
| 78 private: | |
| 79 Scanner* scanner_; | |
| 80 bool complete_; | |
| 81 }; | |
| 82 | |
| 83 Scanner(); | |
| 84 | |
| 85 void Initialize(i::UTF16Buffer* stream); | |
| 86 | |
| 87 // Returns the next token. | |
| 88 i::Token::Value Next(); | |
| 89 | |
| 90 // Returns the current token again. | |
| 91 i::Token::Value current_token() { return current_.token; } | |
| 92 | |
| 93 // One token look-ahead (past the token returned by Next()). | |
| 94 i::Token::Value peek() const { return next_.token; } | |
| 95 | |
| 96 // Returns true if there was a line terminator before the peek'ed token. | |
| 97 bool has_line_terminator_before_next() const { | |
| 98 return has_line_terminator_before_next_; | |
| 99 } | |
| 100 | |
| 101 struct Location { | |
| 102 Location(int b, int e) : beg_pos(b), end_pos(e) { } | |
| 103 Location() : beg_pos(0), end_pos(0) { } | |
| 104 int beg_pos; | |
| 105 int end_pos; | |
| 106 }; | |
| 107 | |
| 108 // Returns the location information for the current token | |
| 109 // (the token returned by Next()). | |
| 110 Location location() const { return current_.location; } | |
| 111 // Returns the location information for the look-ahead token | |
| 112 // (the token returned by peek()). | |
| 113 Location peek_location() const { return next_.location; } | |
| 114 | |
| 115 // Returns the literal string, if any, for the current token (the | |
| 116 // token returned by Next()). The string is 0-terminated and in | |
| 117 // UTF-8 format; they may contain 0-characters. Literal strings are | |
| 118 // collected for identifiers, strings, and numbers. | |
| 119 // These functions only give the correct result if the literal | |
| 120 // was scanned between calls to StartLiteral() and TerminateLiteral(). | |
| 121 const char* literal_string() const { | |
| 122 return current_.literal_chars; | |
| 123 } | |
| 124 | |
| 125 int literal_length() const { | |
| 126 // Excluding terminal '\x00' added by TerminateLiteral(). | |
| 127 return current_.literal_length - 1; | |
| 128 } | |
| 129 | |
| 130 i::Vector<const char> literal() const { | |
| 131 return i::Vector<const char>(literal_string(), literal_length()); | |
| 132 } | |
| 133 | |
| 134 // Returns the literal string for the next token (the token that | |
| 135 // would be returned if Next() were called). | |
| 136 const char* next_literal_string() const { | |
| 137 return next_.literal_chars; | |
| 138 } | |
| 139 | |
| 140 // Returns the length of the next token (that would be returned if | |
| 141 // Next() were called). | |
| 142 int next_literal_length() const { | |
| 143 // Excluding terminal '\x00' added by TerminateLiteral(). | |
| 144 return next_.literal_length - 1; | |
| 145 } | |
| 146 | |
| 147 i::Vector<const char> next_literal() const { | |
| 148 return i::Vector<const char>(next_literal_string(), next_literal_length()); | |
| 149 } | |
| 150 | |
| 151 // Scans the input as a regular expression pattern, previous | |
| 152 // character(s) must be /(=). Returns true if a pattern is scanned. | |
| 153 bool ScanRegExpPattern(bool seen_equal); | |
| 154 // Returns true if regexp flags are scanned (always since flags can | |
| 155 // be empty). | |
| 156 bool ScanRegExpFlags(); | |
| 157 | |
| 158 // Seek forward to the given position. This operation does not | |
| 159 // work in general, for instance when there are pushed back | |
| 160 // characters, but works for seeking forward until simple delimiter | |
| 161 // tokens, which is what it is used for. | |
| 162 void SeekForward(int pos); | |
| 163 | |
| 164 bool stack_overflow() { return stack_overflow_; } | |
| 165 | |
| 166 static const int kCharacterLookaheadBufferSize = 1; | |
| 167 static const int kNoEndPosition = 1; | |
| 168 | |
| 169 private: | |
| 170 // The current and look-ahead token. | |
| 171 struct TokenDesc { | |
| 172 i::Token::Value token; | |
| 173 Location location; | |
| 174 const char* literal_chars; | |
| 175 int literal_length; | |
| 176 }; | |
| 177 | |
| 178 // Default stack limit is 128K pointers. | |
| 179 static const int kMaxStackSize = 128 * 1024 * sizeof(void*); // NOLINT. | |
| 180 | |
| 181 void Init(unibrow::CharacterStream* stream); | |
| 182 | |
| 183 // Literal buffer support | |
| 184 inline void StartLiteral(LiteralType type); | |
| 185 inline void AddLiteralChar(uc32 ch); | |
| 186 inline void AddLiteralCharAdvance(); | |
| 187 inline void TerminateLiteral(); | |
| 188 // Stops scanning of a literal, e.g., due to an encountered error. | |
| 189 inline void DropLiteral(); | |
| 190 | |
| 191 // Low-level scanning support. | |
| 192 void Advance() { c0_ = source_->Advance(); } | |
| 193 void PushBack(uc32 ch) { | |
| 194 source_->PushBack(ch); | |
| 195 c0_ = ch; | |
| 196 } | |
| 197 | |
| 198 bool SkipWhiteSpace(); | |
| 199 | |
| 200 i::Token::Value SkipSingleLineComment(); | |
| 201 i::Token::Value SkipMultiLineComment(); | |
| 202 | |
| 203 inline i::Token::Value Select(i::Token::Value tok); | |
| 204 inline i::Token::Value Select(uc32 next, | |
| 205 i::Token::Value then, | |
| 206 i::Token::Value else_); | |
| 207 | |
| 208 // Scans a single JavaScript token. | |
| 209 void Scan(); | |
| 210 | |
| 211 void ScanDecimalDigits(); | |
| 212 i::Token::Value ScanNumber(bool seen_period); | |
| 213 i::Token::Value ScanIdentifier(); | |
| 214 uc32 ScanHexEscape(uc32 c, int length); | |
| 215 uc32 ScanOctalEscape(uc32 c, int length); | |
| 216 void ScanEscape(); | |
| 217 i::Token::Value ScanString(); | |
| 218 | |
| 219 // Scans a possible HTML comment -- begins with '<!'. | |
| 220 i::Token::Value ScanHtmlComment(); | |
| 221 | |
| 222 // Return the current source position. | |
| 223 int source_pos() { | |
| 224 return source_->pos() - kCharacterLookaheadBufferSize; | |
| 225 } | |
| 226 | |
| 227 // Decodes a unicode escape-sequence which is part of an identifier. | |
| 228 // If the escape sequence cannot be decoded the result is kBadRune. | |
| 229 uc32 ScanIdentifierUnicodeEscape(); | |
| 230 | |
| 231 PreScannerStackGuard stack_guard_; | |
| 232 | |
| 233 TokenDesc current_; // desc for current token (as returned by Next()) | |
| 234 TokenDesc next_; // desc for next token (one token look-ahead) | |
| 235 bool has_line_terminator_before_next_; | |
| 236 | |
| 237 // Source. | |
| 238 i::UTF16Buffer* source_; | |
| 239 | |
| 240 // Buffer to hold literal values (identifiers, strings, numerals, regexps and | |
| 241 // regexp flags) using '\x00'-terminated UTF-8 encoding. | |
| 242 // Handles allocation internally. | |
| 243 // Notice that the '\x00' termination is meaningless for strings and regexps | |
| 244 // which may contain the zero-character, but can be used as terminator for | |
| 245 // identifiers, numerals and regexp flags.Collector | |
| 246 i::LiteralCollector literal_buffer_; | |
| 247 | |
| 248 bool stack_overflow_; | |
| 249 | |
| 250 // One Unicode character look-ahead; c0_ < 0 at the end of the input. | |
| 251 uc32 c0_; | |
| 252 }; | |
| 253 | |
| 254 | |
| 255 // ---------------------------------------------------------------------------- | |
| 256 // Scanner::LiteralScope | |
| 257 | |
| 258 Scanner::LiteralScope::LiteralScope( | |
| 259 Scanner* self, LiteralType type) | |
| 260 : scanner_(self), complete_(false) { | |
| 261 self->StartLiteral(type); | |
| 262 } | |
| 263 | |
| 264 | |
| 265 Scanner::LiteralScope::~LiteralScope() { | |
| 266 if (!complete_) scanner_->DropLiteral(); | |
| 267 } | |
| 268 | |
| 269 void Scanner::LiteralScope::Complete() { | |
| 270 scanner_->TerminateLiteral(); | |
| 271 complete_ = true; | |
| 272 } | |
| 273 | |
| 274 | |
| 275 // ---------------------------------------------------------------------------- | |
| 276 // Scanner. | |
| 277 Scanner::Scanner() | |
| 278 : stack_guard_(kMaxStackSize), | |
| 279 has_line_terminator_before_next_(false), | |
| 280 source_(NULL), | |
| 281 stack_overflow_(false) {} | |
| 282 | |
| 283 | |
| 284 void Scanner::Initialize(i::UTF16Buffer* stream) { | |
| 285 source_ = stream; | |
| 286 | |
| 287 // Initialize current_ to not refer to a literal. | |
| 288 current_.literal_length = 0; | |
| 289 // Reset literal buffer. | |
| 290 literal_buffer_.Reset(); | |
| 291 | |
| 292 // Set c0_ (one character ahead) | |
| 293 ASSERT(kCharacterLookaheadBufferSize == 1); | |
| 294 Advance(); | |
| 295 | |
| 296 // Skip initial whitespace allowing HTML comment ends just like | |
| 297 // after a newline and scan first token. | |
| 298 has_line_terminator_before_next_ = true; | |
| 299 SkipWhiteSpace(); | |
| 300 Scan(); | |
| 301 } | |
| 302 | |
| 303 | |
| 304 i::Token::Value Scanner::Next() { | |
| 305 // BUG 1215673: Find a thread safe way to set a stack limit in | |
| 306 // pre-parse mode. Otherwise, we cannot safely pre-parse from other | |
| 307 // threads. | |
| 308 current_ = next_; | |
| 309 // Check for stack-overflow before returning any tokens. | |
| 310 if (stack_guard_.has_overflowed()) { | |
| 311 stack_overflow_ = true; | |
| 312 next_.token = i::Token::ILLEGAL; | |
| 313 } else { | |
| 314 has_line_terminator_before_next_ = false; | |
| 315 Scan(); | |
| 316 } | |
| 317 return current_.token; | |
| 318 } | |
| 319 | |
| 320 | |
| 321 void Scanner::StartLiteral(LiteralType type) { | |
| 322 // Only record string and literal identifiers when preparsing. | |
| 323 // Those are the ones that are recorded as symbols. Numbers and | |
| 324 // regexps are not recorded. | |
| 325 if (type == kLiteralString || type == kLiteralIdentifier) { | |
| 326 literal_buffer_.StartLiteral(); | |
| 327 } | |
| 328 } | |
| 329 | |
| 330 | |
| 331 void Scanner::AddLiteralChar(uc32 c) { | |
| 332 literal_buffer_.AddChar(c); | |
| 333 } | |
| 334 | |
| 335 | |
| 336 void Scanner::TerminateLiteral() { | |
| 337 i::Vector<const char> chars = literal_buffer_.EndLiteral(); | |
| 338 next_.literal_chars = chars.start(); | |
| 339 next_.literal_length = chars.length(); | |
| 340 } | |
| 341 | |
| 342 | |
| 343 void Scanner::DropLiteral() { | |
| 344 literal_buffer_.DropLiteral(); | |
| 345 } | |
| 346 | |
| 347 | |
| 348 void Scanner::AddLiteralCharAdvance() { | |
| 349 AddLiteralChar(c0_); | |
| 350 Advance(); | |
| 351 } | |
| 352 | |
| 353 | |
| 354 static inline bool IsByteOrderMark(uc32 c) { | |
| 355 // The Unicode value U+FFFE is guaranteed never to be assigned as a | |
| 356 // Unicode character; this implies that in a Unicode context the | |
| 357 // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF | |
| 358 // character expressed in little-endian byte order (since it could | |
| 359 // not be a U+FFFE character expressed in big-endian byte | |
| 360 // order). Nevertheless, we check for it to be compatible with | |
| 361 // Spidermonkey. | |
| 362 return c == 0xFEFF || c == 0xFFFE; | |
| 363 } | |
| 364 | |
| 365 | |
| 366 bool Scanner::SkipWhiteSpace() { | |
| 367 int start_position = source_pos(); | |
| 368 | |
| 369 while (true) { | |
| 370 // We treat byte-order marks (BOMs) as whitespace for better | |
| 371 // compatibility with Spidermonkey and other JavaScript engines. | |
| 372 while (i::ScannerConstants::kIsWhiteSpace.get(c0_) | |
| 373 || IsByteOrderMark(c0_)) { | |
| 374 // IsWhiteSpace() includes line terminators! | |
| 375 if (i::ScannerConstants::kIsLineTerminator.get(c0_)) { | |
| 376 // Ignore line terminators, but remember them. This is necessary | |
| 377 // for automatic semicolon insertion. | |
| 378 has_line_terminator_before_next_ = true; | |
| 379 } | |
| 380 Advance(); | |
| 381 } | |
| 382 | |
| 383 // If there is an HTML comment end '-->' at the beginning of a | |
| 384 // line (with only whitespace in front of it), we treat the rest | |
| 385 // of the line as a comment. This is in line with the way | |
| 386 // SpiderMonkey handles it. | |
| 387 if (c0_ == '-' && has_line_terminator_before_next_) { | |
| 388 Advance(); | |
| 389 if (c0_ == '-') { | |
| 390 Advance(); | |
| 391 if (c0_ == '>') { | |
| 392 // Treat the rest of the line as a comment. | |
| 393 SkipSingleLineComment(); | |
| 394 // Continue skipping white space after the comment. | |
| 395 continue; | |
| 396 } | |
| 397 PushBack('-'); // undo Advance() | |
| 398 } | |
| 399 PushBack('-'); // undo Advance() | |
| 400 } | |
| 401 // Return whether or not we skipped any characters. | |
| 402 return source_pos() != start_position; | |
| 403 } | |
| 404 } | |
| 405 | |
| 406 | |
| 407 i::Token::Value Scanner::SkipSingleLineComment() { | |
| 408 Advance(); | |
| 409 | |
| 410 // The line terminator at the end of the line is not considered | |
| 411 // to be part of the single-line comment; it is recognized | |
| 412 // separately by the lexical grammar and becomes part of the | |
| 413 // stream of input elements for the syntactic grammar (see | |
| 414 // ECMA-262, section 7.4, page 12). | |
| 415 while (c0_ >= 0 && !i::ScannerConstants::kIsLineTerminator.get(c0_)) { | |
| 416 Advance(); | |
| 417 } | |
| 418 | |
| 419 return i::Token::WHITESPACE; | |
| 420 } | |
| 421 | |
| 422 | |
| 423 i::Token::Value Scanner::SkipMultiLineComment() { | |
| 424 ASSERT(c0_ == '*'); | |
| 425 Advance(); | |
| 426 | |
| 427 while (c0_ >= 0) { | |
| 428 char ch = c0_; | |
| 429 Advance(); | |
| 430 // If we have reached the end of the multi-line comment, we | |
| 431 // consume the '/' and insert a whitespace. This way all | |
| 432 // multi-line comments are treated as whitespace - even the ones | |
| 433 // containing line terminators. This contradicts ECMA-262, section | |
| 434 // 7.4, page 12, that says that multi-line comments containing | |
| 435 // line terminators should be treated as a line terminator, but it | |
| 436 // matches the behaviour of SpiderMonkey and KJS. | |
| 437 if (ch == '*' && c0_ == '/') { | |
| 438 c0_ = ' '; | |
| 439 return i::Token::WHITESPACE; | |
| 440 } | |
| 441 } | |
| 442 | |
| 443 // Unterminated multi-line comment. | |
| 444 return i::Token::ILLEGAL; | |
| 445 } | |
| 446 | |
| 447 | |
| 448 i::Token::Value Scanner::ScanHtmlComment() { | |
| 449 // Check for <!-- comments. | |
| 450 ASSERT(c0_ == '!'); | |
| 451 Advance(); | |
| 452 if (c0_ == '-') { | |
| 453 Advance(); | |
| 454 if (c0_ == '-') return SkipSingleLineComment(); | |
| 455 PushBack('-'); // undo Advance() | |
| 456 } | |
| 457 PushBack('!'); // undo Advance() | |
| 458 ASSERT(c0_ == '!'); | |
| 459 return i::Token::LT; | |
| 460 } | |
| 461 | |
| 462 | |
| 463 void Scanner::Scan() { | |
| 464 next_.literal_length = 0; | |
| 465 i::Token::Value token; | |
| 466 do { | |
| 467 // Remember the position of the next token | |
| 468 next_.location.beg_pos = source_pos(); | |
| 469 | |
| 470 switch (c0_) { | |
| 471 case ' ': | |
| 472 case '\t': | |
| 473 Advance(); | |
| 474 token = i::Token::WHITESPACE; | |
| 475 break; | |
| 476 | |
| 477 case '\n': | |
| 478 Advance(); | |
| 479 has_line_terminator_before_next_ = true; | |
| 480 token = i::Token::WHITESPACE; | |
| 481 break; | |
| 482 | |
| 483 case '"': case '\'': | |
| 484 token = ScanString(); | |
| 485 break; | |
| 486 | |
| 487 case '<': | |
| 488 // < <= << <<= <!-- | |
| 489 Advance(); | |
| 490 if (c0_ == '=') { | |
| 491 token = Select(i::Token::LTE); | |
| 492 } else if (c0_ == '<') { | |
| 493 token = Select('=', i::Token::ASSIGN_SHL, i::Token::SHL); | |
| 494 } else if (c0_ == '!') { | |
| 495 token = ScanHtmlComment(); | |
| 496 } else { | |
| 497 token = i::Token::LT; | |
| 498 } | |
| 499 break; | |
| 500 | |
| 501 case '>': | |
| 502 // > >= >> >>= >>> >>>= | |
| 503 Advance(); | |
| 504 if (c0_ == '=') { | |
| 505 token = Select(i::Token::GTE); | |
| 506 } else if (c0_ == '>') { | |
| 507 // >> >>= >>> >>>= | |
| 508 Advance(); | |
| 509 if (c0_ == '=') { | |
| 510 token = Select(i::Token::ASSIGN_SAR); | |
| 511 } else if (c0_ == '>') { | |
| 512 token = Select('=', i::Token::ASSIGN_SHR, i::Token::SHR); | |
| 513 } else { | |
| 514 token = i::Token::SAR; | |
| 515 } | |
| 516 } else { | |
| 517 token = i::Token::GT; | |
| 518 } | |
| 519 break; | |
| 520 | |
| 521 case '=': | |
| 522 // = == === | |
| 523 Advance(); | |
| 524 if (c0_ == '=') { | |
| 525 token = Select('=', i::Token::EQ_STRICT, i::Token::EQ); | |
| 526 } else { | |
| 527 token = i::Token::ASSIGN; | |
| 528 } | |
| 529 break; | |
| 530 | |
| 531 case '!': | |
| 532 // ! != !== | |
| 533 Advance(); | |
| 534 if (c0_ == '=') { | |
| 535 token = Select('=', i::Token::NE_STRICT, i::Token::NE); | |
| 536 } else { | |
| 537 token = i::Token::NOT; | |
| 538 } | |
| 539 break; | |
| 540 | |
| 541 case '+': | |
| 542 // + ++ += | |
| 543 Advance(); | |
| 544 if (c0_ == '+') { | |
| 545 token = Select(i::Token::INC); | |
| 546 } else if (c0_ == '=') { | |
| 547 token = Select(i::Token::ASSIGN_ADD); | |
| 548 } else { | |
| 549 token = i::Token::ADD; | |
| 550 } | |
| 551 break; | |
| 552 | |
| 553 case '-': | |
| 554 // - -- --> -= | |
| 555 Advance(); | |
| 556 if (c0_ == '-') { | |
| 557 Advance(); | |
| 558 if (c0_ == '>' && has_line_terminator_before_next_) { | |
| 559 // For compatibility with SpiderMonkey, we skip lines that | |
| 560 // start with an HTML comment end '-->'. | |
| 561 token = SkipSingleLineComment(); | |
| 562 } else { | |
| 563 token = i::Token::DEC; | |
| 564 } | |
| 565 } else if (c0_ == '=') { | |
| 566 token = Select(i::Token::ASSIGN_SUB); | |
| 567 } else { | |
| 568 token = i::Token::SUB; | |
| 569 } | |
| 570 break; | |
| 571 | |
| 572 case '*': | |
| 573 // * *= | |
| 574 token = Select('=', i::Token::ASSIGN_MUL, i::Token::MUL); | |
| 575 break; | |
| 576 | |
| 577 case '%': | |
| 578 // % %= | |
| 579 token = Select('=', i::Token::ASSIGN_MOD, i::Token::MOD); | |
| 580 break; | |
| 581 | |
| 582 case '/': | |
| 583 // / // /* /= | |
| 584 Advance(); | |
| 585 if (c0_ == '/') { | |
| 586 token = SkipSingleLineComment(); | |
| 587 } else if (c0_ == '*') { | |
| 588 token = SkipMultiLineComment(); | |
| 589 } else if (c0_ == '=') { | |
| 590 token = Select(i::Token::ASSIGN_DIV); | |
| 591 } else { | |
| 592 token = i::Token::DIV; | |
| 593 } | |
| 594 break; | |
| 595 | |
| 596 case '&': | |
| 597 // & && &= | |
| 598 Advance(); | |
| 599 if (c0_ == '&') { | |
| 600 token = Select(i::Token::AND); | |
| 601 } else if (c0_ == '=') { | |
| 602 token = Select(i::Token::ASSIGN_BIT_AND); | |
| 603 } else { | |
| 604 token = i::Token::BIT_AND; | |
| 605 } | |
| 606 break; | |
| 607 | |
| 608 case '|': | |
| 609 // | || |= | |
| 610 Advance(); | |
| 611 if (c0_ == '|') { | |
| 612 token = Select(i::Token::OR); | |
| 613 } else if (c0_ == '=') { | |
| 614 token = Select(i::Token::ASSIGN_BIT_OR); | |
| 615 } else { | |
| 616 token = i::Token::BIT_OR; | |
| 617 } | |
| 618 break; | |
| 619 | |
| 620 case '^': | |
| 621 // ^ ^= | |
| 622 token = Select('=', i::Token::ASSIGN_BIT_XOR, i::Token::BIT_XOR); | |
| 623 break; | |
| 624 | |
| 625 case '.': | |
| 626 // . Number | |
| 627 Advance(); | |
| 628 if (i::IsDecimalDigit(c0_)) { | |
| 629 token = ScanNumber(true); | |
| 630 } else { | |
| 631 token = i::Token::PERIOD; | |
| 632 } | |
| 633 break; | |
| 634 | |
| 635 case ':': | |
| 636 token = Select(i::Token::COLON); | |
| 637 break; | |
| 638 | |
| 639 case ';': | |
| 640 token = Select(i::Token::SEMICOLON); | |
| 641 break; | |
| 642 | |
| 643 case ',': | |
| 644 token = Select(i::Token::COMMA); | |
| 645 break; | |
| 646 | |
| 647 case '(': | |
| 648 token = Select(i::Token::LPAREN); | |
| 649 break; | |
| 650 | |
| 651 case ')': | |
| 652 token = Select(i::Token::RPAREN); | |
| 653 break; | |
| 654 | |
| 655 case '[': | |
| 656 token = Select(i::Token::LBRACK); | |
| 657 break; | |
| 658 | |
| 659 case ']': | |
| 660 token = Select(i::Token::RBRACK); | |
| 661 break; | |
| 662 | |
| 663 case '{': | |
| 664 token = Select(i::Token::LBRACE); | |
| 665 break; | |
| 666 | |
| 667 case '}': | |
| 668 token = Select(i::Token::RBRACE); | |
| 669 break; | |
| 670 | |
| 671 case '?': | |
| 672 token = Select(i::Token::CONDITIONAL); | |
| 673 break; | |
| 674 | |
| 675 case '~': | |
| 676 token = Select(i::Token::BIT_NOT); | |
| 677 break; | |
| 678 | |
| 679 default: | |
| 680 if (i::ScannerConstants::kIsIdentifierStart.get(c0_)) { | |
| 681 token = ScanIdentifier(); | |
| 682 } else if (i::IsDecimalDigit(c0_)) { | |
| 683 token = ScanNumber(false); | |
| 684 } else if (SkipWhiteSpace()) { | |
| 685 token = i::Token::WHITESPACE; | |
| 686 } else if (c0_ < 0) { | |
| 687 token = i::Token::EOS; | |
| 688 } else { | |
| 689 token = Select(i::Token::ILLEGAL); | |
| 690 } | |
| 691 break; | |
| 692 } | |
| 693 | |
| 694 // Continue scanning for tokens as long as we're just skipping | |
| 695 // whitespace. | |
| 696 } while (token == i::Token::WHITESPACE); | |
| 697 | |
| 698 next_.location.end_pos = source_pos(); | |
| 699 next_.token = token; | |
| 700 } | |
| 701 | |
| 702 | |
| 703 void Scanner::SeekForward(int pos) { | |
| 704 source_->SeekForward(pos - 1); | |
| 705 Advance(); | |
| 706 // This function is only called to seek to the location | |
| 707 // of the end of a function (at the "}" token). It doesn't matter | |
| 708 // whether there was a line terminator in the part we skip. | |
| 709 has_line_terminator_before_next_ = false; | |
| 710 Scan(); | |
| 711 } | |
| 712 | |
| 713 | |
| 714 uc32 Scanner::ScanHexEscape(uc32 c, int length) { | |
| 715 ASSERT(length <= 4); // prevent overflow | |
| 716 | |
| 717 uc32 digits[4]; | |
| 718 uc32 x = 0; | |
| 719 for (int i = 0; i < length; i++) { | |
| 720 digits[i] = c0_; | |
| 721 int d = i::HexValue(c0_); | |
| 722 if (d < 0) { | |
| 723 // According to ECMA-262, 3rd, 7.8.4, page 18, these hex escapes | |
| 724 // should be illegal, but other JS VMs just return the | |
| 725 // non-escaped version of the original character. | |
| 726 | |
| 727 // Push back digits read, except the last one (in c0_). | |
| 728 for (int j = i-1; j >= 0; j--) { | |
| 729 PushBack(digits[j]); | |
| 730 } | |
| 731 // Notice: No handling of error - treat it as "\u"->"u". | |
| 732 return c; | |
| 733 } | |
| 734 x = x * 16 + d; | |
| 735 Advance(); | |
| 736 } | |
| 737 | |
| 738 return x; | |
| 739 } | |
| 740 | |
| 741 | |
| 742 // Octal escapes of the forms '\0xx' and '\xxx' are not a part of | |
| 743 // ECMA-262. Other JS VMs support them. | |
| 744 uc32 Scanner::ScanOctalEscape( | |
| 745 uc32 c, int length) { | |
| 746 uc32 x = c - '0'; | |
| 747 for (int i = 0; i < length; i++) { | |
| 748 int d = c0_ - '0'; | |
| 749 if (d < 0 || d > 7) break; | |
| 750 int nx = x * 8 + d; | |
| 751 if (nx >= 256) break; | |
| 752 x = nx; | |
| 753 Advance(); | |
| 754 } | |
| 755 return x; | |
| 756 } | |
| 757 | |
| 758 | |
| 759 void Scanner::ScanEscape() { | |
| 760 uc32 c = c0_; | |
| 761 Advance(); | |
| 762 | |
| 763 // Skip escaped newlines. | |
| 764 if (i::ScannerConstants::kIsLineTerminator.get(c)) { | |
| 765 // Allow CR+LF newlines in multiline string literals. | |
| 766 if (i::IsCarriageReturn(c) && i::IsLineFeed(c0_)) Advance(); | |
| 767 // Allow LF+CR newlines in multiline string literals. | |
| 768 if (i::IsLineFeed(c) && i::IsCarriageReturn(c0_)) Advance(); | |
| 769 return; | |
| 770 } | |
| 771 | |
| 772 switch (c) { | |
| 773 case '\'': // fall through | |
| 774 case '"' : // fall through | |
| 775 case '\\': break; | |
| 776 case 'b' : c = '\b'; break; | |
| 777 case 'f' : c = '\f'; break; | |
| 778 case 'n' : c = '\n'; break; | |
| 779 case 'r' : c = '\r'; break; | |
| 780 case 't' : c = '\t'; break; | |
| 781 case 'u' : c = ScanHexEscape(c, 4); break; | |
| 782 case 'v' : c = '\v'; break; | |
| 783 case 'x' : c = ScanHexEscape(c, 2); break; | |
| 784 case '0' : // fall through | |
| 785 case '1' : // fall through | |
| 786 case '2' : // fall through | |
| 787 case '3' : // fall through | |
| 788 case '4' : // fall through | |
| 789 case '5' : // fall through | |
| 790 case '6' : // fall through | |
| 791 case '7' : c = ScanOctalEscape(c, 2); break; | |
| 792 } | |
| 793 | |
| 794 // According to ECMA-262, 3rd, 7.8.4 (p 18ff) these | |
| 795 // should be illegal, but they are commonly handled | |
| 796 // as non-escaped characters by JS VMs. | |
| 797 AddLiteralChar(c); | |
| 798 } | |
| 799 | |
| 800 | |
| 801 i::Token::Value Scanner::ScanString() { | |
| 802 uc32 quote = c0_; | |
| 803 Advance(); // consume quote | |
| 804 | |
| 805 LiteralScope literal(this, kLiteralString); | |
| 806 while (c0_ != quote && c0_ >= 0 | |
| 807 && !i::ScannerConstants::kIsLineTerminator.get(c0_)) { | |
| 808 uc32 c = c0_; | |
| 809 Advance(); | |
| 810 if (c == '\\') { | |
| 811 if (c0_ < 0) return i::Token::ILLEGAL; | |
| 812 ScanEscape(); | |
| 813 } else { | |
| 814 AddLiteralChar(c); | |
| 815 } | |
| 816 } | |
| 817 if (c0_ != quote) return i::Token::ILLEGAL; | |
| 818 literal.Complete(); | |
| 819 | |
| 820 Advance(); // consume quote | |
| 821 return i::Token::STRING; | |
| 822 } | |
| 823 | |
| 824 | |
| 825 i::Token::Value Scanner::Select( | |
| 826 i::Token::Value tok) { | |
| 827 Advance(); | |
| 828 return tok; | |
| 829 } | |
| 830 | |
| 831 | |
| 832 i::Token::Value Scanner::Select( | |
| 833 uc32 next, | |
| 834 i::Token::Value then, | |
| 835 i::Token::Value else_) { | |
| 836 Advance(); | |
| 837 if (c0_ == next) { | |
| 838 Advance(); | |
| 839 return then; | |
| 840 } else { | |
| 841 return else_; | |
| 842 } | |
| 843 } | |
| 844 | |
| 845 | |
| 846 // Returns true if any decimal digits were scanned, returns false otherwise. | |
| 847 void Scanner::ScanDecimalDigits() { | |
| 848 while (i::IsDecimalDigit(c0_)) | |
| 849 AddLiteralCharAdvance(); | |
| 850 } | |
| 851 | |
| 852 | |
| 853 i::Token::Value Scanner::ScanNumber( | |
| 854 bool seen_period) { | |
| 855 // c0_ is the first digit of the number or the fraction. | |
| 856 ASSERT(i::IsDecimalDigit(c0_)); | |
| 857 | |
| 858 enum { DECIMAL, HEX, OCTAL } kind = DECIMAL; | |
| 859 | |
| 860 LiteralScope literal(this, kLiteralNumber); | |
| 861 if (seen_period) { | |
| 862 // we have already seen a decimal point of the float | |
| 863 AddLiteralChar('.'); | |
| 864 ScanDecimalDigits(); // we know we have at least one digit | |
| 865 | |
| 866 } else { | |
| 867 // if the first character is '0' we must check for octals and hex | |
| 868 if (c0_ == '0') { | |
| 869 AddLiteralCharAdvance(); | |
| 870 | |
| 871 // either 0, 0exxx, 0Exxx, 0.xxx, an octal number, or a hex number | |
| 872 if (c0_ == 'x' || c0_ == 'X') { | |
| 873 // hex number | |
| 874 kind = HEX; | |
| 875 AddLiteralCharAdvance(); | |
| 876 if (!i::IsHexDigit(c0_)) { | |
| 877 // we must have at least one hex digit after 'x'/'X' | |
| 878 return i::Token::ILLEGAL; | |
| 879 } | |
| 880 while (i::IsHexDigit(c0_)) { | |
| 881 AddLiteralCharAdvance(); | |
| 882 } | |
| 883 } else if ('0' <= c0_ && c0_ <= '7') { | |
| 884 // (possible) octal number | |
| 885 kind = OCTAL; | |
| 886 while (true) { | |
| 887 if (c0_ == '8' || c0_ == '9') { | |
| 888 kind = DECIMAL; | |
| 889 break; | |
| 890 } | |
| 891 if (c0_ < '0' || '7' < c0_) break; | |
| 892 AddLiteralCharAdvance(); | |
| 893 } | |
| 894 } | |
| 895 } | |
| 896 | |
| 897 // Parse decimal digits and allow trailing fractional part. | |
| 898 if (kind == DECIMAL) { | |
| 899 ScanDecimalDigits(); // optional | |
| 900 if (c0_ == '.') { | |
| 901 AddLiteralCharAdvance(); | |
| 902 ScanDecimalDigits(); // optional | |
| 903 } | |
| 904 } | |
| 905 } | |
| 906 | |
| 907 // scan exponent, if any | |
| 908 if (c0_ == 'e' || c0_ == 'E') { | |
| 909 ASSERT(kind != HEX); // 'e'/'E' must be scanned as part of the hex number | |
| 910 if (kind == OCTAL) return i::Token::ILLEGAL; | |
| 911 // scan exponent | |
| 912 AddLiteralCharAdvance(); | |
| 913 if (c0_ == '+' || c0_ == '-') | |
| 914 AddLiteralCharAdvance(); | |
| 915 if (!i::IsDecimalDigit(c0_)) { | |
| 916 // we must have at least one decimal digit after 'e'/'E' | |
| 917 return i::Token::ILLEGAL; | |
| 918 } | |
| 919 ScanDecimalDigits(); | |
| 920 } | |
| 921 | |
| 922 // The source character immediately following a numeric literal must | |
| 923 // not be an identifier start or a decimal digit; see ECMA-262 | |
| 924 // section 7.8.3, page 17 (note that we read only one decimal digit | |
| 925 // if the value is 0). | |
| 926 if (i::IsDecimalDigit(c0_) | |
| 927 || i::ScannerConstants::kIsIdentifierStart.get(c0_)) | |
| 928 return i::Token::ILLEGAL; | |
| 929 | |
| 930 literal.Complete(); | |
| 931 | |
| 932 return i::Token::NUMBER; | |
| 933 } | |
| 934 | |
| 935 | |
| 936 uc32 Scanner::ScanIdentifierUnicodeEscape() { | |
| 937 Advance(); | |
| 938 if (c0_ != 'u') return unibrow::Utf8::kBadChar; | |
| 939 Advance(); | |
| 940 uc32 c = ScanHexEscape('u', 4); | |
| 941 // We do not allow a unicode escape sequence to start another | |
| 942 // unicode escape sequence. | |
| 943 if (c == '\\') return unibrow::Utf8::kBadChar; | |
| 944 return c; | |
| 945 } | |
| 946 | |
| 947 | |
| 948 i::Token::Value Scanner::ScanIdentifier() { | |
| 949 ASSERT(i::ScannerConstants::kIsIdentifierStart.get(c0_)); | |
| 950 | |
| 951 LiteralScope literal(this, kLiteralIdentifier); | |
| 952 i::KeywordMatcher keyword_match; | |
| 953 | |
| 954 // Scan identifier start character. | |
| 955 if (c0_ == '\\') { | |
| 956 uc32 c = ScanIdentifierUnicodeEscape(); | |
| 957 // Only allow legal identifier start characters. | |
| 958 if (!i::ScannerConstants::kIsIdentifierStart.get(c)) { | |
| 959 return i::Token::ILLEGAL; | |
| 960 } | |
| 961 AddLiteralChar(c); | |
| 962 keyword_match.Fail(); | |
| 963 } else { | |
| 964 AddLiteralChar(c0_); | |
| 965 keyword_match.AddChar(c0_); | |
| 966 Advance(); | |
| 967 } | |
| 968 | |
| 969 // Scan the rest of the identifier characters. | |
| 970 while (i::ScannerConstants::kIsIdentifierPart.get(c0_)) { | |
| 971 if (c0_ == '\\') { | |
| 972 uc32 c = ScanIdentifierUnicodeEscape(); | |
| 973 // Only allow legal identifier part characters. | |
| 974 if (!i::ScannerConstants::kIsIdentifierPart.get(c)) { | |
| 975 return i::Token::ILLEGAL; | |
| 976 } | |
| 977 AddLiteralChar(c); | |
| 978 keyword_match.Fail(); | |
| 979 } else { | |
| 980 AddLiteralChar(c0_); | |
| 981 keyword_match.AddChar(c0_); | |
| 982 Advance(); | |
| 983 } | |
| 984 } | |
| 985 literal.Complete(); | |
| 986 | |
| 987 return keyword_match.token(); | |
| 988 } | |
| 989 | |
| 990 | |
| 991 bool Scanner::ScanRegExpPattern(bool seen_equal) { | |
| 992 // Scan: ('/' | '/=') RegularExpressionBody '/' RegularExpressionFlags | |
| 993 bool in_character_class = false; | |
| 994 | |
| 995 // Previous token is either '/' or '/=', in the second case, the | |
| 996 // pattern starts at =. | |
| 997 next_.location.beg_pos = source_pos() - (seen_equal ? 2 : 1); | |
| 998 next_.location.end_pos = source_pos() - (seen_equal ? 1 : 0); | |
| 999 | |
| 1000 // Scan regular expression body: According to ECMA-262, 3rd, 7.8.5, | |
| 1001 // the scanner should pass uninterpreted bodies to the RegExp | |
| 1002 // constructor. | |
| 1003 LiteralScope literal(this, kLiteralRegExp); | |
| 1004 if (seen_equal) | |
| 1005 AddLiteralChar('='); | |
| 1006 | |
| 1007 while (c0_ != '/' || in_character_class) { | |
| 1008 if (i::ScannerConstants::kIsLineTerminator.get(c0_) || c0_ < 0) { | |
| 1009 return false; | |
| 1010 } | |
| 1011 if (c0_ == '\\') { // escaped character | |
| 1012 AddLiteralCharAdvance(); | |
| 1013 if (i::ScannerConstants::kIsLineTerminator.get(c0_) || c0_ < 0) { | |
| 1014 return false; | |
| 1015 } | |
| 1016 AddLiteralCharAdvance(); | |
| 1017 } else { // unescaped character | |
| 1018 if (c0_ == '[') in_character_class = true; | |
| 1019 if (c0_ == ']') in_character_class = false; | |
| 1020 AddLiteralCharAdvance(); | |
| 1021 } | |
| 1022 } | |
| 1023 Advance(); // consume '/' | |
| 1024 | |
| 1025 literal.Complete(); | |
| 1026 | |
| 1027 return true; | |
| 1028 } | |
| 1029 | |
| 1030 bool Scanner::ScanRegExpFlags() { | |
| 1031 // Scan regular expression flags. | |
| 1032 LiteralScope literal(this, kLiteralRegExpFlags); | |
| 1033 while (i::ScannerConstants::kIsIdentifierPart.get(c0_)) { | |
| 1034 if (c0_ == '\\') { | |
| 1035 uc32 c = ScanIdentifierUnicodeEscape(); | |
| 1036 if (c != static_cast<uc32>(unibrow::Utf8::kBadChar)) { | |
| 1037 // We allow any escaped character, unlike the restriction on | |
| 1038 // IdentifierPart when it is used to build an IdentifierName. | |
| 1039 AddLiteralChar(c); | |
| 1040 continue; | |
| 1041 } | |
| 1042 } | |
| 1043 AddLiteralCharAdvance(); | |
| 1044 } | |
| 1045 literal.Complete(); | |
| 1046 | |
| 1047 next_.location.end_pos = source_pos() - 1; | |
| 1048 return true; | |
| 1049 } | |
| 1050 | |
| 1051 | |
| 1052 } } // namespace v8::preparser | |
| 1053 | |
| 1054 #endif // V8_PRESCANNER_H_ | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 5188009:
Merge preparser Scanner with main JavaScript scanner. (Closed)
