1 //===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements the tentative parsing portions of the Parser 11 // interfaces, for ambiguity resolution. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Parse/Parser.h" 16 #include "clang/Parse/ParseDiagnostic.h" 17 #include "clang/Sema/ParsedTemplate.h" 18 using namespace clang; 19 20 /// isCXXDeclarationStatement - C++-specialized function that disambiguates 21 /// between a declaration or an expression statement, when parsing function 22 /// bodies. Returns true for declaration, false for expression. 23 /// 24 /// declaration-statement: 25 /// block-declaration 26 /// 27 /// block-declaration: 28 /// simple-declaration 29 /// asm-definition 30 /// namespace-alias-definition 31 /// using-declaration 32 /// using-directive 33 /// [C++0x] static_assert-declaration 34 /// 35 /// asm-definition: 36 /// 'asm' '(' string-literal ')' ';' 37 /// 38 /// namespace-alias-definition: 39 /// 'namespace' identifier = qualified-namespace-specifier ';' 40 /// 41 /// using-declaration: 42 /// 'using' typename[opt] '::'[opt] nested-name-specifier 43 /// unqualified-id ';' 44 /// 'using' '::' unqualified-id ; 45 /// 46 /// using-directive: 47 /// 'using' 'namespace' '::'[opt] nested-name-specifier[opt] 48 /// namespace-name ';' 49 /// 50 bool Parser::isCXXDeclarationStatement() { 51 switch (Tok.getKind()) { 52 // asm-definition 53 case tok::kw_asm: 54 // namespace-alias-definition 55 case tok::kw_namespace: 56 // using-declaration 57 // using-directive 58 case tok::kw_using: 59 // static_assert-declaration 60 case tok::kw_static_assert: 61 case tok::kw__Static_assert: 62 return true; 63 // simple-declaration 64 default: 65 return isCXXSimpleDeclaration(/*AllowForRangeDecl=*/false); 66 } 67 } 68 69 /// isCXXSimpleDeclaration - C++-specialized function that disambiguates 70 /// between a simple-declaration or an expression-statement. 71 /// If during the disambiguation process a parsing error is encountered, 72 /// the function returns true to let the declaration parsing code handle it. 73 /// Returns false if the statement is disambiguated as expression. 74 /// 75 /// simple-declaration: 76 /// decl-specifier-seq init-declarator-list[opt] ';' 77 /// 78 /// (if AllowForRangeDecl specified) 79 /// for ( for-range-declaration : for-range-initializer ) statement 80 /// for-range-declaration: 81 /// attribute-specifier-seqopt type-specifier-seq declarator 82 bool Parser::isCXXSimpleDeclaration(bool AllowForRangeDecl) { 83 // C++ 6.8p1: 84 // There is an ambiguity in the grammar involving expression-statements and 85 // declarations: An expression-statement with a function-style explicit type 86 // conversion (5.2.3) as its leftmost subexpression can be indistinguishable 87 // from a declaration where the first declarator starts with a '('. In those 88 // cases the statement is a declaration. [Note: To disambiguate, the whole 89 // statement might have to be examined to determine if it is an 90 // expression-statement or a declaration]. 91 92 // C++ 6.8p3: 93 // The disambiguation is purely syntactic; that is, the meaning of the names 94 // occurring in such a statement, beyond whether they are type-names or not, 95 // is not generally used in or changed by the disambiguation. Class 96 // templates are instantiated as necessary to determine if a qualified name 97 // is a type-name. Disambiguation precedes parsing, and a statement 98 // disambiguated as a declaration may be an ill-formed declaration. 99 100 // We don't have to parse all of the decl-specifier-seq part. There's only 101 // an ambiguity if the first decl-specifier is 102 // simple-type-specifier/typename-specifier followed by a '(', which may 103 // indicate a function-style cast expression. 104 // isCXXDeclarationSpecifier will return TPResult::Ambiguous only in such 105 // a case. 106 107 bool InvalidAsDeclaration = false; 108 TPResult TPR = isCXXDeclarationSpecifier(TPResult::False, 109 &InvalidAsDeclaration); 110 if (TPR != TPResult::Ambiguous) 111 return TPR != TPResult::False; // Returns true for TPResult::True or 112 // TPResult::Error. 113 114 // FIXME: TryParseSimpleDeclaration doesn't look past the first initializer, 115 // and so gets some cases wrong. We can't carry on if we've already seen 116 // something which makes this statement invalid as a declaration in this case, 117 // since it can cause us to misparse valid code. Revisit this once 118 // TryParseInitDeclaratorList is fixed. 119 if (InvalidAsDeclaration) 120 return false; 121 122 // FIXME: Add statistics about the number of ambiguous statements encountered 123 // and how they were resolved (number of declarations+number of expressions). 124 125 // Ok, we have a simple-type-specifier/typename-specifier followed by a '(', 126 // or an identifier which doesn't resolve as anything. We need tentative 127 // parsing... 128 129 TentativeParsingAction PA(*this); 130 TPR = TryParseSimpleDeclaration(AllowForRangeDecl); 131 PA.Revert(); 132 133 // In case of an error, let the declaration parsing code handle it. 134 if (TPR == TPResult::Error) 135 return true; 136 137 // Declarations take precedence over expressions. 138 if (TPR == TPResult::Ambiguous) 139 TPR = TPResult::True; 140 141 assert(TPR == TPResult::True || TPR == TPResult::False); 142 return TPR == TPResult::True; 143 } 144 145 /// Try to consume a token sequence that we've already identified as 146 /// (potentially) starting a decl-specifier. 147 Parser::TPResult Parser::TryConsumeDeclarationSpecifier() { 148 switch (Tok.getKind()) { 149 case tok::kw__Atomic: 150 if (NextToken().isNot(tok::l_paren)) { 151 ConsumeToken(); 152 break; 153 } 154 // Fall through. 155 case tok::kw_typeof: 156 case tok::kw___attribute: 157 case tok::kw___underlying_type: { 158 ConsumeToken(); 159 if (Tok.isNot(tok::l_paren)) 160 return TPResult::Error; 161 ConsumeParen(); 162 if (!SkipUntil(tok::r_paren)) 163 return TPResult::Error; 164 break; 165 } 166 167 case tok::kw_class: 168 case tok::kw_struct: 169 case tok::kw_union: 170 case tok::kw___interface: 171 case tok::kw_enum: 172 // elaborated-type-specifier: 173 // class-key attribute-specifier-seq[opt] 174 // nested-name-specifier[opt] identifier 175 // class-key nested-name-specifier[opt] template[opt] simple-template-id 176 // enum nested-name-specifier[opt] identifier 177 // 178 // FIXME: We don't support class-specifiers nor enum-specifiers here. 179 ConsumeToken(); 180 181 // Skip attributes. 182 while (Tok.isOneOf(tok::l_square, tok::kw___attribute, tok::kw___declspec, 183 tok::kw_alignas)) { 184 if (Tok.is(tok::l_square)) { 185 ConsumeBracket(); 186 if (!SkipUntil(tok::r_square)) 187 return TPResult::Error; 188 } else { 189 ConsumeToken(); 190 if (Tok.isNot(tok::l_paren)) 191 return TPResult::Error; 192 ConsumeParen(); 193 if (!SkipUntil(tok::r_paren)) 194 return TPResult::Error; 195 } 196 } 197 198 if (Tok.isOneOf(tok::identifier, tok::coloncolon, tok::kw_decltype, 199 tok::annot_template_id) && 200 TryAnnotateCXXScopeToken()) 201 return TPResult::Error; 202 if (Tok.is(tok::annot_cxxscope)) 203 ConsumeToken(); 204 if (Tok.isNot(tok::identifier) && Tok.isNot(tok::annot_template_id)) 205 return TPResult::Error; 206 ConsumeToken(); 207 break; 208 209 case tok::annot_cxxscope: 210 ConsumeToken(); 211 // Fall through. 212 default: 213 ConsumeToken(); 214 215 if (getLangOpts().ObjC1 && Tok.is(tok::less)) 216 return TryParseProtocolQualifiers(); 217 break; 218 } 219 220 return TPResult::Ambiguous; 221 } 222 223 /// simple-declaration: 224 /// decl-specifier-seq init-declarator-list[opt] ';' 225 /// 226 /// (if AllowForRangeDecl specified) 227 /// for ( for-range-declaration : for-range-initializer ) statement 228 /// for-range-declaration: 229 /// attribute-specifier-seqopt type-specifier-seq declarator 230 /// 231 Parser::TPResult Parser::TryParseSimpleDeclaration(bool AllowForRangeDecl) { 232 if (TryConsumeDeclarationSpecifier() == TPResult::Error) 233 return TPResult::Error; 234 235 // Two decl-specifiers in a row conclusively disambiguate this as being a 236 // simple-declaration. Don't bother calling isCXXDeclarationSpecifier in the 237 // overwhelmingly common case that the next token is a '('. 238 if (Tok.isNot(tok::l_paren)) { 239 TPResult TPR = isCXXDeclarationSpecifier(); 240 if (TPR == TPResult::Ambiguous) 241 return TPResult::True; 242 if (TPR == TPResult::True || TPR == TPResult::Error) 243 return TPR; 244 assert(TPR == TPResult::False); 245 } 246 247 TPResult TPR = TryParseInitDeclaratorList(); 248 if (TPR != TPResult::Ambiguous) 249 return TPR; 250 251 if (Tok.isNot(tok::semi) && (!AllowForRangeDecl || Tok.isNot(tok::colon))) 252 return TPResult::False; 253 254 return TPResult::Ambiguous; 255 } 256 257 /// Tentatively parse an init-declarator-list in order to disambiguate it from 258 /// an expression. 259 /// 260 /// init-declarator-list: 261 /// init-declarator 262 /// init-declarator-list ',' init-declarator 263 /// 264 /// init-declarator: 265 /// declarator initializer[opt] 266 /// [GNU] declarator simple-asm-expr[opt] attributes[opt] initializer[opt] 267 /// 268 /// initializer: 269 /// brace-or-equal-initializer 270 /// '(' expression-list ')' 271 /// 272 /// brace-or-equal-initializer: 273 /// '=' initializer-clause 274 /// [C++11] braced-init-list 275 /// 276 /// initializer-clause: 277 /// assignment-expression 278 /// braced-init-list 279 /// 280 /// braced-init-list: 281 /// '{' initializer-list ','[opt] '}' 282 /// '{' '}' 283 /// 284 Parser::TPResult Parser::TryParseInitDeclaratorList() { 285 while (1) { 286 // declarator 287 TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/); 288 if (TPR != TPResult::Ambiguous) 289 return TPR; 290 291 // [GNU] simple-asm-expr[opt] attributes[opt] 292 if (Tok.isOneOf(tok::kw_asm, tok::kw___attribute)) 293 return TPResult::True; 294 295 // initializer[opt] 296 if (Tok.is(tok::l_paren)) { 297 // Parse through the parens. 298 ConsumeParen(); 299 if (!SkipUntil(tok::r_paren, StopAtSemi)) 300 return TPResult::Error; 301 } else if (Tok.is(tok::l_brace)) { 302 // A left-brace here is sufficient to disambiguate the parse; an 303 // expression can never be followed directly by a braced-init-list. 304 return TPResult::True; 305 } else if (Tok.is(tok::equal) || isTokIdentifier_in()) { 306 // MSVC and g++ won't examine the rest of declarators if '=' is 307 // encountered; they just conclude that we have a declaration. 308 // EDG parses the initializer completely, which is the proper behavior 309 // for this case. 310 // 311 // At present, Clang follows MSVC and g++, since the parser does not have 312 // the ability to parse an expression fully without recording the 313 // results of that parse. 314 // FIXME: Handle this case correctly. 315 // 316 // Also allow 'in' after an Objective-C declaration as in: 317 // for (int (^b)(void) in array). Ideally this should be done in the 318 // context of parsing for-init-statement of a foreach statement only. But, 319 // in any other context 'in' is invalid after a declaration and parser 320 // issues the error regardless of outcome of this decision. 321 // FIXME: Change if above assumption does not hold. 322 return TPResult::True; 323 } 324 325 if (!TryConsumeToken(tok::comma)) 326 break; 327 } 328 329 return TPResult::Ambiguous; 330 } 331 332 /// isCXXConditionDeclaration - Disambiguates between a declaration or an 333 /// expression for a condition of a if/switch/while/for statement. 334 /// If during the disambiguation process a parsing error is encountered, 335 /// the function returns true to let the declaration parsing code handle it. 336 /// 337 /// condition: 338 /// expression 339 /// type-specifier-seq declarator '=' assignment-expression 340 /// [C++11] type-specifier-seq declarator '=' initializer-clause 341 /// [C++11] type-specifier-seq declarator braced-init-list 342 /// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt] 343 /// '=' assignment-expression 344 /// 345 bool Parser::isCXXConditionDeclaration() { 346 TPResult TPR = isCXXDeclarationSpecifier(); 347 if (TPR != TPResult::Ambiguous) 348 return TPR != TPResult::False; // Returns true for TPResult::True or 349 // TPResult::Error. 350 351 // FIXME: Add statistics about the number of ambiguous statements encountered 352 // and how they were resolved (number of declarations+number of expressions). 353 354 // Ok, we have a simple-type-specifier/typename-specifier followed by a '('. 355 // We need tentative parsing... 356 357 TentativeParsingAction PA(*this); 358 359 // type-specifier-seq 360 TryConsumeDeclarationSpecifier(); 361 assert(Tok.is(tok::l_paren) && "Expected '('"); 362 363 // declarator 364 TPR = TryParseDeclarator(false/*mayBeAbstract*/); 365 366 // In case of an error, let the declaration parsing code handle it. 367 if (TPR == TPResult::Error) 368 TPR = TPResult::True; 369 370 if (TPR == TPResult::Ambiguous) { 371 // '=' 372 // [GNU] simple-asm-expr[opt] attributes[opt] 373 if (Tok.isOneOf(tok::equal, tok::kw_asm, tok::kw___attribute)) 374 TPR = TPResult::True; 375 else if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) 376 TPR = TPResult::True; 377 else 378 TPR = TPResult::False; 379 } 380 381 PA.Revert(); 382 383 assert(TPR == TPResult::True || TPR == TPResult::False); 384 return TPR == TPResult::True; 385 } 386 387 /// \brief Determine whether the next set of tokens contains a type-id. 388 /// 389 /// The context parameter states what context we're parsing right 390 /// now, which affects how this routine copes with the token 391 /// following the type-id. If the context is TypeIdInParens, we have 392 /// already parsed the '(' and we will cease lookahead when we hit 393 /// the corresponding ')'. If the context is 394 /// TypeIdAsTemplateArgument, we've already parsed the '<' or ',' 395 /// before this template argument, and will cease lookahead when we 396 /// hit a '>', '>>' (in C++0x), or ','. Returns true for a type-id 397 /// and false for an expression. If during the disambiguation 398 /// process a parsing error is encountered, the function returns 399 /// true to let the declaration parsing code handle it. 400 /// 401 /// type-id: 402 /// type-specifier-seq abstract-declarator[opt] 403 /// 404 bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) { 405 406 isAmbiguous = false; 407 408 // C++ 8.2p2: 409 // The ambiguity arising from the similarity between a function-style cast and 410 // a type-id can occur in different contexts. The ambiguity appears as a 411 // choice between a function-style cast expression and a declaration of a 412 // type. The resolution is that any construct that could possibly be a type-id 413 // in its syntactic context shall be considered a type-id. 414 415 TPResult TPR = isCXXDeclarationSpecifier(); 416 if (TPR != TPResult::Ambiguous) 417 return TPR != TPResult::False; // Returns true for TPResult::True or 418 // TPResult::Error. 419 420 // FIXME: Add statistics about the number of ambiguous statements encountered 421 // and how they were resolved (number of declarations+number of expressions). 422 423 // Ok, we have a simple-type-specifier/typename-specifier followed by a '('. 424 // We need tentative parsing... 425 426 TentativeParsingAction PA(*this); 427 428 // type-specifier-seq 429 TryConsumeDeclarationSpecifier(); 430 assert(Tok.is(tok::l_paren) && "Expected '('"); 431 432 // declarator 433 TPR = TryParseDeclarator(true/*mayBeAbstract*/, false/*mayHaveIdentifier*/); 434 435 // In case of an error, let the declaration parsing code handle it. 436 if (TPR == TPResult::Error) 437 TPR = TPResult::True; 438 439 if (TPR == TPResult::Ambiguous) { 440 // We are supposed to be inside parens, so if after the abstract declarator 441 // we encounter a ')' this is a type-id, otherwise it's an expression. 442 if (Context == TypeIdInParens && Tok.is(tok::r_paren)) { 443 TPR = TPResult::True; 444 isAmbiguous = true; 445 446 // We are supposed to be inside a template argument, so if after 447 // the abstract declarator we encounter a '>', '>>' (in C++0x), or 448 // ',', this is a type-id. Otherwise, it's an expression. 449 } else if (Context == TypeIdAsTemplateArgument && 450 (Tok.isOneOf(tok::greater, tok::comma) || 451 (getLangOpts().CPlusPlus11 && Tok.is(tok::greatergreater)))) { 452 TPR = TPResult::True; 453 isAmbiguous = true; 454 455 } else 456 TPR = TPResult::False; 457 } 458 459 PA.Revert(); 460 461 assert(TPR == TPResult::True || TPR == TPResult::False); 462 return TPR == TPResult::True; 463 } 464 465 /// \brief Returns true if this is a C++11 attribute-specifier. Per 466 /// C++11 [dcl.attr.grammar]p6, two consecutive left square bracket tokens 467 /// always introduce an attribute. In Objective-C++11, this rule does not 468 /// apply if either '[' begins a message-send. 469 /// 470 /// If Disambiguate is true, we try harder to determine whether a '[[' starts 471 /// an attribute-specifier, and return CAK_InvalidAttributeSpecifier if not. 472 /// 473 /// If OuterMightBeMessageSend is true, we assume the outer '[' is either an 474 /// Obj-C message send or the start of an attribute. Otherwise, we assume it 475 /// is not an Obj-C message send. 476 /// 477 /// C++11 [dcl.attr.grammar]: 478 /// 479 /// attribute-specifier: 480 /// '[' '[' attribute-list ']' ']' 481 /// alignment-specifier 482 /// 483 /// attribute-list: 484 /// attribute[opt] 485 /// attribute-list ',' attribute[opt] 486 /// attribute '...' 487 /// attribute-list ',' attribute '...' 488 /// 489 /// attribute: 490 /// attribute-token attribute-argument-clause[opt] 491 /// 492 /// attribute-token: 493 /// identifier 494 /// identifier '::' identifier 495 /// 496 /// attribute-argument-clause: 497 /// '(' balanced-token-seq ')' 498 Parser::CXX11AttributeKind 499 Parser::isCXX11AttributeSpecifier(bool Disambiguate, 500 bool OuterMightBeMessageSend) { 501 if (Tok.is(tok::kw_alignas)) 502 return CAK_AttributeSpecifier; 503 504 if (Tok.isNot(tok::l_square) || NextToken().isNot(tok::l_square)) 505 return CAK_NotAttributeSpecifier; 506 507 // No tentative parsing if we don't need to look for ']]' or a lambda. 508 if (!Disambiguate && !getLangOpts().ObjC1) 509 return CAK_AttributeSpecifier; 510 511 TentativeParsingAction PA(*this); 512 513 // Opening brackets were checked for above. 514 ConsumeBracket(); 515 516 // Outside Obj-C++11, treat anything with a matching ']]' as an attribute. 517 if (!getLangOpts().ObjC1) { 518 ConsumeBracket(); 519 520 bool IsAttribute = SkipUntil(tok::r_square); 521 IsAttribute &= Tok.is(tok::r_square); 522 523 PA.Revert(); 524 525 return IsAttribute ? CAK_AttributeSpecifier : CAK_InvalidAttributeSpecifier; 526 } 527 528 // In Obj-C++11, we need to distinguish four situations: 529 // 1a) int x[[attr]]; C++11 attribute. 530 // 1b) [[attr]]; C++11 statement attribute. 531 // 2) int x[[obj](){ return 1; }()]; Lambda in array size/index. 532 // 3a) int x[[obj get]]; Message send in array size/index. 533 // 3b) [[Class alloc] init]; Message send in message send. 534 // 4) [[obj]{ return self; }() doStuff]; Lambda in message send. 535 // (1) is an attribute, (2) is ill-formed, and (3) and (4) are accepted. 536 537 // If we have a lambda-introducer, then this is definitely not a message send. 538 // FIXME: If this disambiguation is too slow, fold the tentative lambda parse 539 // into the tentative attribute parse below. 540 LambdaIntroducer Intro; 541 if (!TryParseLambdaIntroducer(Intro)) { 542 // A lambda cannot end with ']]', and an attribute must. 543 bool IsAttribute = Tok.is(tok::r_square); 544 545 PA.Revert(); 546 547 if (IsAttribute) 548 // Case 1: C++11 attribute. 549 return CAK_AttributeSpecifier; 550 551 if (OuterMightBeMessageSend) 552 // Case 4: Lambda in message send. 553 return CAK_NotAttributeSpecifier; 554 555 // Case 2: Lambda in array size / index. 556 return CAK_InvalidAttributeSpecifier; 557 } 558 559 ConsumeBracket(); 560 561 // If we don't have a lambda-introducer, then we have an attribute or a 562 // message-send. 563 bool IsAttribute = true; 564 while (Tok.isNot(tok::r_square)) { 565 if (Tok.is(tok::comma)) { 566 // Case 1: Stray commas can only occur in attributes. 567 PA.Revert(); 568 return CAK_AttributeSpecifier; 569 } 570 571 // Parse the attribute-token, if present. 572 // C++11 [dcl.attr.grammar]: 573 // If a keyword or an alternative token that satisfies the syntactic 574 // requirements of an identifier is contained in an attribute-token, 575 // it is considered an identifier. 576 SourceLocation Loc; 577 if (!TryParseCXX11AttributeIdentifier(Loc)) { 578 IsAttribute = false; 579 break; 580 } 581 if (Tok.is(tok::coloncolon)) { 582 ConsumeToken(); 583 if (!TryParseCXX11AttributeIdentifier(Loc)) { 584 IsAttribute = false; 585 break; 586 } 587 } 588 589 // Parse the attribute-argument-clause, if present. 590 if (Tok.is(tok::l_paren)) { 591 ConsumeParen(); 592 if (!SkipUntil(tok::r_paren)) { 593 IsAttribute = false; 594 break; 595 } 596 } 597 598 TryConsumeToken(tok::ellipsis); 599 600 if (!TryConsumeToken(tok::comma)) 601 break; 602 } 603 604 // An attribute must end ']]'. 605 if (IsAttribute) { 606 if (Tok.is(tok::r_square)) { 607 ConsumeBracket(); 608 IsAttribute = Tok.is(tok::r_square); 609 } else { 610 IsAttribute = false; 611 } 612 } 613 614 PA.Revert(); 615 616 if (IsAttribute) 617 // Case 1: C++11 statement attribute. 618 return CAK_AttributeSpecifier; 619 620 // Case 3: Message send. 621 return CAK_NotAttributeSpecifier; 622 } 623 624 Parser::TPResult Parser::TryParsePtrOperatorSeq() { 625 while (true) { 626 if (Tok.isOneOf(tok::coloncolon, tok::identifier)) 627 if (TryAnnotateCXXScopeToken(true)) 628 return TPResult::Error; 629 630 if (Tok.isOneOf(tok::star, tok::amp, tok::caret, tok::ampamp) || 631 (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) { 632 // ptr-operator 633 ConsumeToken(); 634 while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw_restrict, 635 tok::kw__Nonnull, tok::kw__Nullable, 636 tok::kw__Null_unspecified)) 637 ConsumeToken(); 638 } else { 639 return TPResult::True; 640 } 641 } 642 } 643 644 /// operator-function-id: 645 /// 'operator' operator 646 /// 647 /// operator: one of 648 /// new delete new[] delete[] + - * / % ^ [...] 649 /// 650 /// conversion-function-id: 651 /// 'operator' conversion-type-id 652 /// 653 /// conversion-type-id: 654 /// type-specifier-seq conversion-declarator[opt] 655 /// 656 /// conversion-declarator: 657 /// ptr-operator conversion-declarator[opt] 658 /// 659 /// literal-operator-id: 660 /// 'operator' string-literal identifier 661 /// 'operator' user-defined-string-literal 662 Parser::TPResult Parser::TryParseOperatorId() { 663 assert(Tok.is(tok::kw_operator)); 664 ConsumeToken(); 665 666 // Maybe this is an operator-function-id. 667 switch (Tok.getKind()) { 668 case tok::kw_new: case tok::kw_delete: 669 ConsumeToken(); 670 if (Tok.is(tok::l_square) && NextToken().is(tok::r_square)) { 671 ConsumeBracket(); 672 ConsumeBracket(); 673 } 674 return TPResult::True; 675 676 #define OVERLOADED_OPERATOR(Name, Spelling, Token, Unary, Binary, MemOnly) \ 677 case tok::Token: 678 #define OVERLOADED_OPERATOR_MULTI(Name, Spelling, Unary, Binary, MemOnly) 679 #include "clang/Basic/OperatorKinds.def" 680 ConsumeToken(); 681 return TPResult::True; 682 683 case tok::l_square: 684 if (NextToken().is(tok::r_square)) { 685 ConsumeBracket(); 686 ConsumeBracket(); 687 return TPResult::True; 688 } 689 break; 690 691 case tok::l_paren: 692 if (NextToken().is(tok::r_paren)) { 693 ConsumeParen(); 694 ConsumeParen(); 695 return TPResult::True; 696 } 697 break; 698 699 default: 700 break; 701 } 702 703 // Maybe this is a literal-operator-id. 704 if (getLangOpts().CPlusPlus11 && isTokenStringLiteral()) { 705 bool FoundUDSuffix = false; 706 do { 707 FoundUDSuffix |= Tok.hasUDSuffix(); 708 ConsumeStringToken(); 709 } while (isTokenStringLiteral()); 710 711 if (!FoundUDSuffix) { 712 if (Tok.is(tok::identifier)) 713 ConsumeToken(); 714 else 715 return TPResult::Error; 716 } 717 return TPResult::True; 718 } 719 720 // Maybe this is a conversion-function-id. 721 bool AnyDeclSpecifiers = false; 722 while (true) { 723 TPResult TPR = isCXXDeclarationSpecifier(); 724 if (TPR == TPResult::Error) 725 return TPR; 726 if (TPR == TPResult::False) { 727 if (!AnyDeclSpecifiers) 728 return TPResult::Error; 729 break; 730 } 731 if (TryConsumeDeclarationSpecifier() == TPResult::Error) 732 return TPResult::Error; 733 AnyDeclSpecifiers = true; 734 } 735 return TryParsePtrOperatorSeq(); 736 } 737 738 /// declarator: 739 /// direct-declarator 740 /// ptr-operator declarator 741 /// 742 /// direct-declarator: 743 /// declarator-id 744 /// direct-declarator '(' parameter-declaration-clause ')' 745 /// cv-qualifier-seq[opt] exception-specification[opt] 746 /// direct-declarator '[' constant-expression[opt] ']' 747 /// '(' declarator ')' 748 /// [GNU] '(' attributes declarator ')' 749 /// 750 /// abstract-declarator: 751 /// ptr-operator abstract-declarator[opt] 752 /// direct-abstract-declarator 753 /// ... 754 /// 755 /// direct-abstract-declarator: 756 /// direct-abstract-declarator[opt] 757 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] 758 /// exception-specification[opt] 759 /// direct-abstract-declarator[opt] '[' constant-expression[opt] ']' 760 /// '(' abstract-declarator ')' 761 /// 762 /// ptr-operator: 763 /// '*' cv-qualifier-seq[opt] 764 /// '&' 765 /// [C++0x] '&&' [TODO] 766 /// '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt] 767 /// 768 /// cv-qualifier-seq: 769 /// cv-qualifier cv-qualifier-seq[opt] 770 /// 771 /// cv-qualifier: 772 /// 'const' 773 /// 'volatile' 774 /// 775 /// declarator-id: 776 /// '...'[opt] id-expression 777 /// 778 /// id-expression: 779 /// unqualified-id 780 /// qualified-id [TODO] 781 /// 782 /// unqualified-id: 783 /// identifier 784 /// operator-function-id 785 /// conversion-function-id 786 /// literal-operator-id 787 /// '~' class-name [TODO] 788 /// '~' decltype-specifier [TODO] 789 /// template-id [TODO] 790 /// 791 Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract, 792 bool mayHaveIdentifier) { 793 // declarator: 794 // direct-declarator 795 // ptr-operator declarator 796 if (TryParsePtrOperatorSeq() == TPResult::Error) 797 return TPResult::Error; 798 799 // direct-declarator: 800 // direct-abstract-declarator: 801 if (Tok.is(tok::ellipsis)) 802 ConsumeToken(); 803 804 if ((Tok.isOneOf(tok::identifier, tok::kw_operator) || 805 (Tok.is(tok::annot_cxxscope) && (NextToken().is(tok::identifier) || 806 NextToken().is(tok::kw_operator)))) && 807 mayHaveIdentifier) { 808 // declarator-id 809 if (Tok.is(tok::annot_cxxscope)) 810 ConsumeToken(); 811 else if (Tok.is(tok::identifier)) 812 TentativelyDeclaredIdentifiers.push_back(Tok.getIdentifierInfo()); 813 if (Tok.is(tok::kw_operator)) { 814 if (TryParseOperatorId() == TPResult::Error) 815 return TPResult::Error; 816 } else 817 ConsumeToken(); 818 } else if (Tok.is(tok::l_paren)) { 819 ConsumeParen(); 820 if (mayBeAbstract && 821 (Tok.is(tok::r_paren) || // 'int()' is a function. 822 // 'int(...)' is a function. 823 (Tok.is(tok::ellipsis) && NextToken().is(tok::r_paren)) || 824 isDeclarationSpecifier())) { // 'int(int)' is a function. 825 // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] 826 // exception-specification[opt] 827 TPResult TPR = TryParseFunctionDeclarator(); 828 if (TPR != TPResult::Ambiguous) 829 return TPR; 830 } else { 831 // '(' declarator ')' 832 // '(' attributes declarator ')' 833 // '(' abstract-declarator ')' 834 if (Tok.isOneOf(tok::kw___attribute, tok::kw___declspec, tok::kw___cdecl, 835 tok::kw___stdcall, tok::kw___fastcall, tok::kw___thiscall, 836 tok::kw___vectorcall, tok::kw___unaligned)) 837 return TPResult::True; // attributes indicate declaration 838 TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier); 839 if (TPR != TPResult::Ambiguous) 840 return TPR; 841 if (Tok.isNot(tok::r_paren)) 842 return TPResult::False; 843 ConsumeParen(); 844 } 845 } else if (!mayBeAbstract) { 846 return TPResult::False; 847 } 848 849 while (1) { 850 TPResult TPR(TPResult::Ambiguous); 851 852 // abstract-declarator: ... 853 if (Tok.is(tok::ellipsis)) 854 ConsumeToken(); 855 856 if (Tok.is(tok::l_paren)) { 857 // Check whether we have a function declarator or a possible ctor-style 858 // initializer that follows the declarator. Note that ctor-style 859 // initializers are not possible in contexts where abstract declarators 860 // are allowed. 861 if (!mayBeAbstract && !isCXXFunctionDeclarator()) 862 break; 863 864 // direct-declarator '(' parameter-declaration-clause ')' 865 // cv-qualifier-seq[opt] exception-specification[opt] 866 ConsumeParen(); 867 TPR = TryParseFunctionDeclarator(); 868 } else if (Tok.is(tok::l_square)) { 869 // direct-declarator '[' constant-expression[opt] ']' 870 // direct-abstract-declarator[opt] '[' constant-expression[opt] ']' 871 TPR = TryParseBracketDeclarator(); 872 } else { 873 break; 874 } 875 876 if (TPR != TPResult::Ambiguous) 877 return TPR; 878 } 879 880 return TPResult::Ambiguous; 881 } 882 883 Parser::TPResult 884 Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) { 885 switch (Kind) { 886 // Obviously starts an expression. 887 case tok::numeric_constant: 888 case tok::char_constant: 889 case tok::wide_char_constant: 890 case tok::utf8_char_constant: 891 case tok::utf16_char_constant: 892 case tok::utf32_char_constant: 893 case tok::string_literal: 894 case tok::wide_string_literal: 895 case tok::utf8_string_literal: 896 case tok::utf16_string_literal: 897 case tok::utf32_string_literal: 898 case tok::l_square: 899 case tok::l_paren: 900 case tok::amp: 901 case tok::ampamp: 902 case tok::star: 903 case tok::plus: 904 case tok::plusplus: 905 case tok::minus: 906 case tok::minusminus: 907 case tok::tilde: 908 case tok::exclaim: 909 case tok::kw_sizeof: 910 case tok::kw___func__: 911 case tok::kw_const_cast: 912 case tok::kw_delete: 913 case tok::kw_dynamic_cast: 914 case tok::kw_false: 915 case tok::kw_new: 916 case tok::kw_operator: 917 case tok::kw_reinterpret_cast: 918 case tok::kw_static_cast: 919 case tok::kw_this: 920 case tok::kw_throw: 921 case tok::kw_true: 922 case tok::kw_typeid: 923 case tok::kw_alignof: 924 case tok::kw_noexcept: 925 case tok::kw_nullptr: 926 case tok::kw__Alignof: 927 case tok::kw___null: 928 case tok::kw___alignof: 929 case tok::kw___builtin_choose_expr: 930 case tok::kw___builtin_offsetof: 931 case tok::kw___builtin_va_arg: 932 case tok::kw___imag: 933 case tok::kw___real: 934 case tok::kw___FUNCTION__: 935 case tok::kw___FUNCDNAME__: 936 case tok::kw___FUNCSIG__: 937 case tok::kw_L__FUNCTION__: 938 case tok::kw___PRETTY_FUNCTION__: 939 case tok::kw___uuidof: 940 #define TYPE_TRAIT(N,Spelling,K) \ 941 case tok::kw_##Spelling: 942 #include "clang/Basic/TokenKinds.def" 943 return TPResult::True; 944 945 // Obviously starts a type-specifier-seq: 946 case tok::kw_char: 947 case tok::kw_const: 948 case tok::kw_double: 949 case tok::kw_enum: 950 case tok::kw_half: 951 case tok::kw_float: 952 case tok::kw_int: 953 case tok::kw_long: 954 case tok::kw___int64: 955 case tok::kw___int128: 956 case tok::kw_restrict: 957 case tok::kw_short: 958 case tok::kw_signed: 959 case tok::kw_struct: 960 case tok::kw_union: 961 case tok::kw_unsigned: 962 case tok::kw_void: 963 case tok::kw_volatile: 964 case tok::kw__Bool: 965 case tok::kw__Complex: 966 case tok::kw_class: 967 case tok::kw_typename: 968 case tok::kw_wchar_t: 969 case tok::kw_char16_t: 970 case tok::kw_char32_t: 971 case tok::kw__Decimal32: 972 case tok::kw__Decimal64: 973 case tok::kw__Decimal128: 974 case tok::kw___interface: 975 case tok::kw___thread: 976 case tok::kw_thread_local: 977 case tok::kw__Thread_local: 978 case tok::kw_typeof: 979 case tok::kw___underlying_type: 980 case tok::kw___cdecl: 981 case tok::kw___stdcall: 982 case tok::kw___fastcall: 983 case tok::kw___thiscall: 984 case tok::kw___vectorcall: 985 case tok::kw___unaligned: 986 case tok::kw___vector: 987 case tok::kw___pixel: 988 case tok::kw___bool: 989 case tok::kw__Atomic: 990 case tok::kw___unknown_anytype: 991 return TPResult::False; 992 993 default: 994 break; 995 } 996 997 return TPResult::Ambiguous; 998 } 999 1000 bool Parser::isTentativelyDeclared(IdentifierInfo *II) { 1001 return std::find(TentativelyDeclaredIdentifiers.begin(), 1002 TentativelyDeclaredIdentifiers.end(), II) 1003 != TentativelyDeclaredIdentifiers.end(); 1004 } 1005 1006 namespace { 1007 class TentativeParseCCC : public CorrectionCandidateCallback { 1008 public: 1009 TentativeParseCCC(const Token &Next) { 1010 WantRemainingKeywords = false; 1011 WantTypeSpecifiers = Next.isOneOf(tok::l_paren, tok::r_paren, tok::greater, 1012 tok::l_brace, tok::identifier); 1013 } 1014 1015 bool ValidateCandidate(const TypoCorrection &Candidate) override { 1016 // Reject any candidate that only resolves to instance members since they 1017 // aren't viable as standalone identifiers instead of member references. 1018 if (Candidate.isResolved() && !Candidate.isKeyword() && 1019 std::all_of(Candidate.begin(), Candidate.end(), 1020 [](NamedDecl *ND) { return ND->isCXXInstanceMember(); })) 1021 return false; 1022 1023 return CorrectionCandidateCallback::ValidateCandidate(Candidate); 1024 } 1025 }; 1026 } 1027 /// isCXXDeclarationSpecifier - Returns TPResult::True if it is a declaration 1028 /// specifier, TPResult::False if it is not, TPResult::Ambiguous if it could 1029 /// be either a decl-specifier or a function-style cast, and TPResult::Error 1030 /// if a parsing error was found and reported. 1031 /// 1032 /// If HasMissingTypename is provided, a name with a dependent scope specifier 1033 /// will be treated as ambiguous if the 'typename' keyword is missing. If this 1034 /// happens, *HasMissingTypename will be set to 'true'. This will also be used 1035 /// as an indicator that undeclared identifiers (which will trigger a later 1036 /// parse error) should be treated as types. Returns TPResult::Ambiguous in 1037 /// such cases. 1038 /// 1039 /// decl-specifier: 1040 /// storage-class-specifier 1041 /// type-specifier 1042 /// function-specifier 1043 /// 'friend' 1044 /// 'typedef' 1045 /// [C++11] 'constexpr' 1046 /// [GNU] attributes declaration-specifiers[opt] 1047 /// 1048 /// storage-class-specifier: 1049 /// 'register' 1050 /// 'static' 1051 /// 'extern' 1052 /// 'mutable' 1053 /// 'auto' 1054 /// [GNU] '__thread' 1055 /// [C++11] 'thread_local' 1056 /// [C11] '_Thread_local' 1057 /// 1058 /// function-specifier: 1059 /// 'inline' 1060 /// 'virtual' 1061 /// 'explicit' 1062 /// 1063 /// typedef-name: 1064 /// identifier 1065 /// 1066 /// type-specifier: 1067 /// simple-type-specifier 1068 /// class-specifier 1069 /// enum-specifier 1070 /// elaborated-type-specifier 1071 /// typename-specifier 1072 /// cv-qualifier 1073 /// 1074 /// simple-type-specifier: 1075 /// '::'[opt] nested-name-specifier[opt] type-name 1076 /// '::'[opt] nested-name-specifier 'template' 1077 /// simple-template-id [TODO] 1078 /// 'char' 1079 /// 'wchar_t' 1080 /// 'bool' 1081 /// 'short' 1082 /// 'int' 1083 /// 'long' 1084 /// 'signed' 1085 /// 'unsigned' 1086 /// 'float' 1087 /// 'double' 1088 /// 'void' 1089 /// [GNU] typeof-specifier 1090 /// [GNU] '_Complex' 1091 /// [C++11] 'auto' 1092 /// [GNU] '__auto_type' 1093 /// [C++11] 'decltype' ( expression ) 1094 /// [C++1y] 'decltype' ( 'auto' ) 1095 /// 1096 /// type-name: 1097 /// class-name 1098 /// enum-name 1099 /// typedef-name 1100 /// 1101 /// elaborated-type-specifier: 1102 /// class-key '::'[opt] nested-name-specifier[opt] identifier 1103 /// class-key '::'[opt] nested-name-specifier[opt] 'template'[opt] 1104 /// simple-template-id 1105 /// 'enum' '::'[opt] nested-name-specifier[opt] identifier 1106 /// 1107 /// enum-name: 1108 /// identifier 1109 /// 1110 /// enum-specifier: 1111 /// 'enum' identifier[opt] '{' enumerator-list[opt] '}' 1112 /// 'enum' identifier[opt] '{' enumerator-list ',' '}' 1113 /// 1114 /// class-specifier: 1115 /// class-head '{' member-specification[opt] '}' 1116 /// 1117 /// class-head: 1118 /// class-key identifier[opt] base-clause[opt] 1119 /// class-key nested-name-specifier identifier base-clause[opt] 1120 /// class-key nested-name-specifier[opt] simple-template-id 1121 /// base-clause[opt] 1122 /// 1123 /// class-key: 1124 /// 'class' 1125 /// 'struct' 1126 /// 'union' 1127 /// 1128 /// cv-qualifier: 1129 /// 'const' 1130 /// 'volatile' 1131 /// [GNU] restrict 1132 /// 1133 Parser::TPResult 1134 Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult, 1135 bool *HasMissingTypename) { 1136 switch (Tok.getKind()) { 1137 case tok::identifier: { 1138 // Check for need to substitute AltiVec __vector keyword 1139 // for "vector" identifier. 1140 if (TryAltiVecVectorToken()) 1141 return TPResult::True; 1142 1143 const Token &Next = NextToken(); 1144 // In 'foo bar', 'foo' is always a type name outside of Objective-C. 1145 if (!getLangOpts().ObjC1 && Next.is(tok::identifier)) 1146 return TPResult::True; 1147 1148 if (Next.isNot(tok::coloncolon) && Next.isNot(tok::less)) { 1149 // Determine whether this is a valid expression. If not, we will hit 1150 // a parse error one way or another. In that case, tell the caller that 1151 // this is ambiguous. Typo-correct to type and expression keywords and 1152 // to types and identifiers, in order to try to recover from errors. 1153 switch (TryAnnotateName(false /* no nested name specifier */, 1154 llvm::make_unique<TentativeParseCCC>(Next))) { 1155 case ANK_Error: 1156 return TPResult::Error; 1157 case ANK_TentativeDecl: 1158 return TPResult::False; 1159 case ANK_TemplateName: 1160 // A bare type template-name which can't be a template template 1161 // argument is an error, and was probably intended to be a type. 1162 return GreaterThanIsOperator ? TPResult::True : TPResult::False; 1163 case ANK_Unresolved: 1164 return HasMissingTypename ? TPResult::Ambiguous : TPResult::False; 1165 case ANK_Success: 1166 break; 1167 } 1168 assert(Tok.isNot(tok::identifier) && 1169 "TryAnnotateName succeeded without producing an annotation"); 1170 } else { 1171 // This might possibly be a type with a dependent scope specifier and 1172 // a missing 'typename' keyword. Don't use TryAnnotateName in this case, 1173 // since it will annotate as a primary expression, and we want to use the 1174 // "missing 'typename'" logic. 1175 if (TryAnnotateTypeOrScopeToken()) 1176 return TPResult::Error; 1177 // If annotation failed, assume it's a non-type. 1178 // FIXME: If this happens due to an undeclared identifier, treat it as 1179 // ambiguous. 1180 if (Tok.is(tok::identifier)) 1181 return TPResult::False; 1182 } 1183 1184 // We annotated this token as something. Recurse to handle whatever we got. 1185 return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename); 1186 } 1187 1188 case tok::kw_typename: // typename T::type 1189 // Annotate typenames and C++ scope specifiers. If we get one, just 1190 // recurse to handle whatever we get. 1191 if (TryAnnotateTypeOrScopeToken()) 1192 return TPResult::Error; 1193 return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename); 1194 1195 case tok::coloncolon: { // ::foo::bar 1196 const Token &Next = NextToken(); 1197 if (Next.isOneOf(tok::kw_new, // ::new 1198 tok::kw_delete)) // ::delete 1199 return TPResult::False; 1200 } 1201 // Fall through. 1202 case tok::kw___super: 1203 case tok::kw_decltype: 1204 // Annotate typenames and C++ scope specifiers. If we get one, just 1205 // recurse to handle whatever we get. 1206 if (TryAnnotateTypeOrScopeToken()) 1207 return TPResult::Error; 1208 return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename); 1209 1210 // decl-specifier: 1211 // storage-class-specifier 1212 // type-specifier 1213 // function-specifier 1214 // 'friend' 1215 // 'typedef' 1216 // 'constexpr' 1217 // 'concept' 1218 case tok::kw_friend: 1219 case tok::kw_typedef: 1220 case tok::kw_constexpr: 1221 case tok::kw_concept: 1222 // storage-class-specifier 1223 case tok::kw_register: 1224 case tok::kw_static: 1225 case tok::kw_extern: 1226 case tok::kw_mutable: 1227 case tok::kw_auto: 1228 case tok::kw___thread: 1229 case tok::kw_thread_local: 1230 case tok::kw__Thread_local: 1231 // function-specifier 1232 case tok::kw_inline: 1233 case tok::kw_virtual: 1234 case tok::kw_explicit: 1235 1236 // Modules 1237 case tok::kw___module_private__: 1238 1239 // Debugger support 1240 case tok::kw___unknown_anytype: 1241 1242 // type-specifier: 1243 // simple-type-specifier 1244 // class-specifier 1245 // enum-specifier 1246 // elaborated-type-specifier 1247 // typename-specifier 1248 // cv-qualifier 1249 1250 // class-specifier 1251 // elaborated-type-specifier 1252 case tok::kw_class: 1253 case tok::kw_struct: 1254 case tok::kw_union: 1255 case tok::kw___interface: 1256 // enum-specifier 1257 case tok::kw_enum: 1258 // cv-qualifier 1259 case tok::kw_const: 1260 case tok::kw_volatile: 1261 1262 // GNU 1263 case tok::kw_restrict: 1264 case tok::kw__Complex: 1265 case tok::kw___attribute: 1266 case tok::kw___auto_type: 1267 return TPResult::True; 1268 1269 // Microsoft 1270 case tok::kw___declspec: 1271 case tok::kw___cdecl: 1272 case tok::kw___stdcall: 1273 case tok::kw___fastcall: 1274 case tok::kw___thiscall: 1275 case tok::kw___vectorcall: 1276 case tok::kw___w64: 1277 case tok::kw___sptr: 1278 case tok::kw___uptr: 1279 case tok::kw___ptr64: 1280 case tok::kw___ptr32: 1281 case tok::kw___forceinline: 1282 case tok::kw___unaligned: 1283 case tok::kw__Nonnull: 1284 case tok::kw__Nullable: 1285 case tok::kw__Null_unspecified: 1286 case tok::kw___kindof: 1287 return TPResult::True; 1288 1289 // Borland 1290 case tok::kw___pascal: 1291 return TPResult::True; 1292 1293 // AltiVec 1294 case tok::kw___vector: 1295 return TPResult::True; 1296 1297 case tok::annot_template_id: { 1298 TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok); 1299 if (TemplateId->Kind != TNK_Type_template) 1300 return TPResult::False; 1301 CXXScopeSpec SS; 1302 AnnotateTemplateIdTokenAsType(); 1303 assert(Tok.is(tok::annot_typename)); 1304 goto case_typename; 1305 } 1306 1307 case tok::annot_cxxscope: // foo::bar or ::foo::bar, but already parsed 1308 // We've already annotated a scope; try to annotate a type. 1309 if (TryAnnotateTypeOrScopeToken()) 1310 return TPResult::Error; 1311 if (!Tok.is(tok::annot_typename)) { 1312 // If the next token is an identifier or a type qualifier, then this 1313 // can't possibly be a valid expression either. 1314 if (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier)) { 1315 CXXScopeSpec SS; 1316 Actions.RestoreNestedNameSpecifierAnnotation(Tok.getAnnotationValue(), 1317 Tok.getAnnotationRange(), 1318 SS); 1319 if (SS.getScopeRep() && SS.getScopeRep()->isDependent()) { 1320 TentativeParsingAction PA(*this); 1321 ConsumeToken(); 1322 ConsumeToken(); 1323 bool isIdentifier = Tok.is(tok::identifier); 1324 TPResult TPR = TPResult::False; 1325 if (!isIdentifier) 1326 TPR = isCXXDeclarationSpecifier(BracedCastResult, 1327 HasMissingTypename); 1328 PA.Revert(); 1329 1330 if (isIdentifier || 1331 TPR == TPResult::True || TPR == TPResult::Error) 1332 return TPResult::Error; 1333 1334 if (HasMissingTypename) { 1335 // We can't tell whether this is a missing 'typename' or a valid 1336 // expression. 1337 *HasMissingTypename = true; 1338 return TPResult::Ambiguous; 1339 } 1340 } else { 1341 // Try to resolve the name. If it doesn't exist, assume it was 1342 // intended to name a type and keep disambiguating. 1343 switch (TryAnnotateName(false /* SS is not dependent */)) { 1344 case ANK_Error: 1345 return TPResult::Error; 1346 case ANK_TentativeDecl: 1347 return TPResult::False; 1348 case ANK_TemplateName: 1349 // A bare type template-name which can't be a template template 1350 // argument is an error, and was probably intended to be a type. 1351 return GreaterThanIsOperator ? TPResult::True : TPResult::False; 1352 case ANK_Unresolved: 1353 return HasMissingTypename ? TPResult::Ambiguous 1354 : TPResult::False; 1355 case ANK_Success: 1356 // Annotated it, check again. 1357 assert(Tok.isNot(tok::annot_cxxscope) || 1358 NextToken().isNot(tok::identifier)); 1359 return isCXXDeclarationSpecifier(BracedCastResult, 1360 HasMissingTypename); 1361 } 1362 } 1363 } 1364 return TPResult::False; 1365 } 1366 // If that succeeded, fallthrough into the generic simple-type-id case. 1367 1368 // The ambiguity resides in a simple-type-specifier/typename-specifier 1369 // followed by a '('. The '(' could either be the start of: 1370 // 1371 // direct-declarator: 1372 // '(' declarator ')' 1373 // 1374 // direct-abstract-declarator: 1375 // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] 1376 // exception-specification[opt] 1377 // '(' abstract-declarator ')' 1378 // 1379 // or part of a function-style cast expression: 1380 // 1381 // simple-type-specifier '(' expression-list[opt] ')' 1382 // 1383 1384 // simple-type-specifier: 1385 1386 case tok::annot_typename: 1387 case_typename: 1388 // In Objective-C, we might have a protocol-qualified type. 1389 if (getLangOpts().ObjC1 && NextToken().is(tok::less)) { 1390 // Tentatively parse the protocol qualifiers. 1391 TentativeParsingAction PA(*this); 1392 ConsumeToken(); // The type token 1393 1394 TPResult TPR = TryParseProtocolQualifiers(); 1395 bool isFollowedByParen = Tok.is(tok::l_paren); 1396 bool isFollowedByBrace = Tok.is(tok::l_brace); 1397 1398 PA.Revert(); 1399 1400 if (TPR == TPResult::Error) 1401 return TPResult::Error; 1402 1403 if (isFollowedByParen) 1404 return TPResult::Ambiguous; 1405 1406 if (getLangOpts().CPlusPlus11 && isFollowedByBrace) 1407 return BracedCastResult; 1408 1409 return TPResult::True; 1410 } 1411 1412 case tok::kw_char: 1413 case tok::kw_wchar_t: 1414 case tok::kw_char16_t: 1415 case tok::kw_char32_t: 1416 case tok::kw_bool: 1417 case tok::kw_short: 1418 case tok::kw_int: 1419 case tok::kw_long: 1420 case tok::kw___int64: 1421 case tok::kw___int128: 1422 case tok::kw_signed: 1423 case tok::kw_unsigned: 1424 case tok::kw_half: 1425 case tok::kw_float: 1426 case tok::kw_double: 1427 case tok::kw_void: 1428 case tok::annot_decltype: 1429 if (NextToken().is(tok::l_paren)) 1430 return TPResult::Ambiguous; 1431 1432 // This is a function-style cast in all cases we disambiguate other than 1433 // one: 1434 // struct S { 1435 // enum E : int { a = 4 }; // enum 1436 // enum E : int { 4 }; // bit-field 1437 // }; 1438 if (getLangOpts().CPlusPlus11 && NextToken().is(tok::l_brace)) 1439 return BracedCastResult; 1440 1441 if (isStartOfObjCClassMessageMissingOpenBracket()) 1442 return TPResult::False; 1443 1444 return TPResult::True; 1445 1446 // GNU typeof support. 1447 case tok::kw_typeof: { 1448 if (NextToken().isNot(tok::l_paren)) 1449 return TPResult::True; 1450 1451 TentativeParsingAction PA(*this); 1452 1453 TPResult TPR = TryParseTypeofSpecifier(); 1454 bool isFollowedByParen = Tok.is(tok::l_paren); 1455 bool isFollowedByBrace = Tok.is(tok::l_brace); 1456 1457 PA.Revert(); 1458 1459 if (TPR == TPResult::Error) 1460 return TPResult::Error; 1461 1462 if (isFollowedByParen) 1463 return TPResult::Ambiguous; 1464 1465 if (getLangOpts().CPlusPlus11 && isFollowedByBrace) 1466 return BracedCastResult; 1467 1468 return TPResult::True; 1469 } 1470 1471 // C++0x type traits support 1472 case tok::kw___underlying_type: 1473 return TPResult::True; 1474 1475 // C11 _Atomic 1476 case tok::kw__Atomic: 1477 return TPResult::True; 1478 1479 default: 1480 return TPResult::False; 1481 } 1482 } 1483 1484 bool Parser::isCXXDeclarationSpecifierAType() { 1485 switch (Tok.getKind()) { 1486 // typename-specifier 1487 case tok::annot_decltype: 1488 case tok::annot_template_id: 1489 case tok::annot_typename: 1490 case tok::kw_typeof: 1491 case tok::kw___underlying_type: 1492 return true; 1493 1494 // elaborated-type-specifier 1495 case tok::kw_class: 1496 case tok::kw_struct: 1497 case tok::kw_union: 1498 case tok::kw___interface: 1499 case tok::kw_enum: 1500 return true; 1501 1502 // simple-type-specifier 1503 case tok::kw_char: 1504 case tok::kw_wchar_t: 1505 case tok::kw_char16_t: 1506 case tok::kw_char32_t: 1507 case tok::kw_bool: 1508 case tok::kw_short: 1509 case tok::kw_int: 1510 case tok::kw_long: 1511 case tok::kw___int64: 1512 case tok::kw___int128: 1513 case tok::kw_signed: 1514 case tok::kw_unsigned: 1515 case tok::kw_half: 1516 case tok::kw_float: 1517 case tok::kw_double: 1518 case tok::kw_void: 1519 case tok::kw___unknown_anytype: 1520 case tok::kw___auto_type: 1521 return true; 1522 1523 case tok::kw_auto: 1524 return getLangOpts().CPlusPlus11; 1525 1526 case tok::kw__Atomic: 1527 // "_Atomic foo" 1528 return NextToken().is(tok::l_paren); 1529 1530 default: 1531 return false; 1532 } 1533 } 1534 1535 /// [GNU] typeof-specifier: 1536 /// 'typeof' '(' expressions ')' 1537 /// 'typeof' '(' type-name ')' 1538 /// 1539 Parser::TPResult Parser::TryParseTypeofSpecifier() { 1540 assert(Tok.is(tok::kw_typeof) && "Expected 'typeof'!"); 1541 ConsumeToken(); 1542 1543 assert(Tok.is(tok::l_paren) && "Expected '('"); 1544 // Parse through the parens after 'typeof'. 1545 ConsumeParen(); 1546 if (!SkipUntil(tok::r_paren, StopAtSemi)) 1547 return TPResult::Error; 1548 1549 return TPResult::Ambiguous; 1550 } 1551 1552 /// [ObjC] protocol-qualifiers: 1553 //// '<' identifier-list '>' 1554 Parser::TPResult Parser::TryParseProtocolQualifiers() { 1555 assert(Tok.is(tok::less) && "Expected '<' for qualifier list"); 1556 ConsumeToken(); 1557 do { 1558 if (Tok.isNot(tok::identifier)) 1559 return TPResult::Error; 1560 ConsumeToken(); 1561 1562 if (Tok.is(tok::comma)) { 1563 ConsumeToken(); 1564 continue; 1565 } 1566 1567 if (Tok.is(tok::greater)) { 1568 ConsumeToken(); 1569 return TPResult::Ambiguous; 1570 } 1571 } while (false); 1572 1573 return TPResult::Error; 1574 } 1575 1576 /// isCXXFunctionDeclarator - Disambiguates between a function declarator or 1577 /// a constructor-style initializer, when parsing declaration statements. 1578 /// Returns true for function declarator and false for constructor-style 1579 /// initializer. 1580 /// If during the disambiguation process a parsing error is encountered, 1581 /// the function returns true to let the declaration parsing code handle it. 1582 /// 1583 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] 1584 /// exception-specification[opt] 1585 /// 1586 bool Parser::isCXXFunctionDeclarator(bool *IsAmbiguous) { 1587 1588 // C++ 8.2p1: 1589 // The ambiguity arising from the similarity between a function-style cast and 1590 // a declaration mentioned in 6.8 can also occur in the context of a 1591 // declaration. In that context, the choice is between a function declaration 1592 // with a redundant set of parentheses around a parameter name and an object 1593 // declaration with a function-style cast as the initializer. Just as for the 1594 // ambiguities mentioned in 6.8, the resolution is to consider any construct 1595 // that could possibly be a declaration a declaration. 1596 1597 TentativeParsingAction PA(*this); 1598 1599 ConsumeParen(); 1600 bool InvalidAsDeclaration = false; 1601 TPResult TPR = TryParseParameterDeclarationClause(&InvalidAsDeclaration); 1602 if (TPR == TPResult::Ambiguous) { 1603 if (Tok.isNot(tok::r_paren)) 1604 TPR = TPResult::False; 1605 else { 1606 const Token &Next = NextToken(); 1607 if (Next.isOneOf(tok::amp, tok::ampamp, tok::kw_const, tok::kw_volatile, 1608 tok::kw_throw, tok::kw_noexcept, tok::l_square, 1609 tok::l_brace, tok::kw_try, tok::equal, tok::arrow) || 1610 isCXX11VirtSpecifier(Next)) 1611 // The next token cannot appear after a constructor-style initializer, 1612 // and can appear next in a function definition. This must be a function 1613 // declarator. 1614 TPR = TPResult::True; 1615 else if (InvalidAsDeclaration) 1616 // Use the absence of 'typename' as a tie-breaker. 1617 TPR = TPResult::False; 1618 } 1619 } 1620 1621 PA.Revert(); 1622 1623 if (IsAmbiguous && TPR == TPResult::Ambiguous) 1624 *IsAmbiguous = true; 1625 1626 // In case of an error, let the declaration parsing code handle it. 1627 return TPR != TPResult::False; 1628 } 1629 1630 /// parameter-declaration-clause: 1631 /// parameter-declaration-list[opt] '...'[opt] 1632 /// parameter-declaration-list ',' '...' 1633 /// 1634 /// parameter-declaration-list: 1635 /// parameter-declaration 1636 /// parameter-declaration-list ',' parameter-declaration 1637 /// 1638 /// parameter-declaration: 1639 /// attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt] 1640 /// attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt] 1641 /// '=' assignment-expression 1642 /// attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt] 1643 /// attributes[opt] 1644 /// attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt] 1645 /// attributes[opt] '=' assignment-expression 1646 /// 1647 Parser::TPResult 1648 Parser::TryParseParameterDeclarationClause(bool *InvalidAsDeclaration, 1649 bool VersusTemplateArgument) { 1650 1651 if (Tok.is(tok::r_paren)) 1652 return TPResult::Ambiguous; 1653 1654 // parameter-declaration-list[opt] '...'[opt] 1655 // parameter-declaration-list ',' '...' 1656 // 1657 // parameter-declaration-list: 1658 // parameter-declaration 1659 // parameter-declaration-list ',' parameter-declaration 1660 // 1661 while (1) { 1662 // '...'[opt] 1663 if (Tok.is(tok::ellipsis)) { 1664 ConsumeToken(); 1665 if (Tok.is(tok::r_paren)) 1666 return TPResult::True; // '...)' is a sign of a function declarator. 1667 else 1668 return TPResult::False; 1669 } 1670 1671 // An attribute-specifier-seq here is a sign of a function declarator. 1672 if (isCXX11AttributeSpecifier(/*Disambiguate*/false, 1673 /*OuterMightBeMessageSend*/true)) 1674 return TPResult::True; 1675 1676 ParsedAttributes attrs(AttrFactory); 1677 MaybeParseMicrosoftAttributes(attrs); 1678 1679 // decl-specifier-seq 1680 // A parameter-declaration's initializer must be preceded by an '=', so 1681 // decl-specifier-seq '{' is not a parameter in C++11. 1682 TPResult TPR = isCXXDeclarationSpecifier(TPResult::False, 1683 InvalidAsDeclaration); 1684 1685 if (VersusTemplateArgument && TPR == TPResult::True) { 1686 // Consume the decl-specifier-seq. We have to look past it, since a 1687 // type-id might appear here in a template argument. 1688 bool SeenType = false; 1689 do { 1690 SeenType |= isCXXDeclarationSpecifierAType(); 1691 if (TryConsumeDeclarationSpecifier() == TPResult::Error) 1692 return TPResult::Error; 1693 1694 // If we see a parameter name, this can't be a template argument. 1695 if (SeenType && Tok.is(tok::identifier)) 1696 return TPResult::True; 1697 1698 TPR = isCXXDeclarationSpecifier(TPResult::False, 1699 InvalidAsDeclaration); 1700 if (TPR == TPResult::Error) 1701 return TPR; 1702 } while (TPR != TPResult::False); 1703 } else if (TPR == TPResult::Ambiguous) { 1704 // Disambiguate what follows the decl-specifier. 1705 if (TryConsumeDeclarationSpecifier() == TPResult::Error) 1706 return TPResult::Error; 1707 } else 1708 return TPR; 1709 1710 // declarator 1711 // abstract-declarator[opt] 1712 TPR = TryParseDeclarator(true/*mayBeAbstract*/); 1713 if (TPR != TPResult::Ambiguous) 1714 return TPR; 1715 1716 // [GNU] attributes[opt] 1717 if (Tok.is(tok::kw___attribute)) 1718 return TPResult::True; 1719 1720 // If we're disambiguating a template argument in a default argument in 1721 // a class definition versus a parameter declaration, an '=' here 1722 // disambiguates the parse one way or the other. 1723 // If this is a parameter, it must have a default argument because 1724 // (a) the previous parameter did, and 1725 // (b) this must be the first declaration of the function, so we can't 1726 // inherit any default arguments from elsewhere. 1727 // If we see an ')', then we've reached the end of a 1728 // parameter-declaration-clause, and the last param is missing its default 1729 // argument. 1730 if (VersusTemplateArgument) 1731 return Tok.isOneOf(tok::equal, tok::r_paren) ? TPResult::True 1732 : TPResult::False; 1733 1734 if (Tok.is(tok::equal)) { 1735 // '=' assignment-expression 1736 // Parse through assignment-expression. 1737 // FIXME: assignment-expression may contain an unparenthesized comma. 1738 if (!SkipUntil(tok::comma, tok::r_paren, StopAtSemi | StopBeforeMatch)) 1739 return TPResult::Error; 1740 } 1741 1742 if (Tok.is(tok::ellipsis)) { 1743 ConsumeToken(); 1744 if (Tok.is(tok::r_paren)) 1745 return TPResult::True; // '...)' is a sign of a function declarator. 1746 else 1747 return TPResult::False; 1748 } 1749 1750 if (!TryConsumeToken(tok::comma)) 1751 break; 1752 } 1753 1754 return TPResult::Ambiguous; 1755 } 1756 1757 /// TryParseFunctionDeclarator - We parsed a '(' and we want to try to continue 1758 /// parsing as a function declarator. 1759 /// If TryParseFunctionDeclarator fully parsed the function declarator, it will 1760 /// return TPResult::Ambiguous, otherwise it will return either False() or 1761 /// Error(). 1762 /// 1763 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] 1764 /// exception-specification[opt] 1765 /// 1766 /// exception-specification: 1767 /// 'throw' '(' type-id-list[opt] ')' 1768 /// 1769 Parser::TPResult Parser::TryParseFunctionDeclarator() { 1770 1771 // The '(' is already parsed. 1772 1773 TPResult TPR = TryParseParameterDeclarationClause(); 1774 if (TPR == TPResult::Ambiguous && Tok.isNot(tok::r_paren)) 1775 TPR = TPResult::False; 1776 1777 if (TPR == TPResult::False || TPR == TPResult::Error) 1778 return TPR; 1779 1780 // Parse through the parens. 1781 if (!SkipUntil(tok::r_paren, StopAtSemi)) 1782 return TPResult::Error; 1783 1784 // cv-qualifier-seq 1785 while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw_restrict)) 1786 ConsumeToken(); 1787 1788 // ref-qualifier[opt] 1789 if (Tok.isOneOf(tok::amp, tok::ampamp)) 1790 ConsumeToken(); 1791 1792 // exception-specification 1793 if (Tok.is(tok::kw_throw)) { 1794 ConsumeToken(); 1795 if (Tok.isNot(tok::l_paren)) 1796 return TPResult::Error; 1797 1798 // Parse through the parens after 'throw'. 1799 ConsumeParen(); 1800 if (!SkipUntil(tok::r_paren, StopAtSemi)) 1801 return TPResult::Error; 1802 } 1803 if (Tok.is(tok::kw_noexcept)) { 1804 ConsumeToken(); 1805 // Possibly an expression as well. 1806 if (Tok.is(tok::l_paren)) { 1807 // Find the matching rparen. 1808 ConsumeParen(); 1809 if (!SkipUntil(tok::r_paren, StopAtSemi)) 1810 return TPResult::Error; 1811 } 1812 } 1813 1814 return TPResult::Ambiguous; 1815 } 1816 1817 /// '[' constant-expression[opt] ']' 1818 /// 1819 Parser::TPResult Parser::TryParseBracketDeclarator() { 1820 ConsumeBracket(); 1821 if (!SkipUntil(tok::r_square, StopAtSemi)) 1822 return TPResult::Error; 1823 1824 return TPResult::Ambiguous; 1825 } 1826