ParseTemplate.cpp revision 219077
1//===--- ParseTemplate.cpp - Template 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 parsing of C++ templates. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Parse/Parser.h" 15#include "clang/Parse/ParseDiagnostic.h" 16#include "clang/Sema/DeclSpec.h" 17#include "clang/Sema/ParsedTemplate.h" 18#include "clang/Sema/Scope.h" 19#include "RAIIObjectsForParser.h" 20using namespace clang; 21 22/// \brief Parse a template declaration, explicit instantiation, or 23/// explicit specialization. 24Decl * 25Parser::ParseDeclarationStartingWithTemplate(unsigned Context, 26 SourceLocation &DeclEnd, 27 AccessSpecifier AS) { 28 if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) 29 return ParseExplicitInstantiation(SourceLocation(), ConsumeToken(), 30 DeclEnd); 31 32 return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS); 33} 34 35/// \brief RAII class that manages the template parameter depth. 36namespace { 37 class TemplateParameterDepthCounter { 38 unsigned &Depth; 39 unsigned AddedLevels; 40 41 public: 42 explicit TemplateParameterDepthCounter(unsigned &Depth) 43 : Depth(Depth), AddedLevels(0) { } 44 45 ~TemplateParameterDepthCounter() { 46 Depth -= AddedLevels; 47 } 48 49 void operator++() { 50 ++Depth; 51 ++AddedLevels; 52 } 53 54 operator unsigned() const { return Depth; } 55 }; 56} 57 58/// \brief Parse a template declaration or an explicit specialization. 59/// 60/// Template declarations include one or more template parameter lists 61/// and either the function or class template declaration. Explicit 62/// specializations contain one or more 'template < >' prefixes 63/// followed by a (possibly templated) declaration. Since the 64/// syntactic form of both features is nearly identical, we parse all 65/// of the template headers together and let semantic analysis sort 66/// the declarations from the explicit specializations. 67/// 68/// template-declaration: [C++ temp] 69/// 'export'[opt] 'template' '<' template-parameter-list '>' declaration 70/// 71/// explicit-specialization: [ C++ temp.expl.spec] 72/// 'template' '<' '>' declaration 73Decl * 74Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context, 75 SourceLocation &DeclEnd, 76 AccessSpecifier AS) { 77 assert((Tok.is(tok::kw_export) || Tok.is(tok::kw_template)) && 78 "Token does not start a template declaration."); 79 80 // Enter template-parameter scope. 81 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 82 83 // Tell the action that names should be checked in the context of 84 // the declaration to come. 85 ParsingDeclRAIIObject ParsingTemplateParams(*this); 86 87 // Parse multiple levels of template headers within this template 88 // parameter scope, e.g., 89 // 90 // template<typename T> 91 // template<typename U> 92 // class A<T>::B { ... }; 93 // 94 // We parse multiple levels non-recursively so that we can build a 95 // single data structure containing all of the template parameter 96 // lists to easily differentiate between the case above and: 97 // 98 // template<typename T> 99 // class A { 100 // template<typename U> class B; 101 // }; 102 // 103 // In the first case, the action for declaring A<T>::B receives 104 // both template parameter lists. In the second case, the action for 105 // defining A<T>::B receives just the inner template parameter list 106 // (and retrieves the outer template parameter list from its 107 // context). 108 bool isSpecialization = true; 109 bool LastParamListWasEmpty = false; 110 TemplateParameterLists ParamLists; 111 TemplateParameterDepthCounter Depth(TemplateParameterDepth); 112 do { 113 // Consume the 'export', if any. 114 SourceLocation ExportLoc; 115 if (Tok.is(tok::kw_export)) { 116 ExportLoc = ConsumeToken(); 117 } 118 119 // Consume the 'template', which should be here. 120 SourceLocation TemplateLoc; 121 if (Tok.is(tok::kw_template)) { 122 TemplateLoc = ConsumeToken(); 123 } else { 124 Diag(Tok.getLocation(), diag::err_expected_template); 125 return 0; 126 } 127 128 // Parse the '<' template-parameter-list '>' 129 SourceLocation LAngleLoc, RAngleLoc; 130 llvm::SmallVector<Decl*, 4> TemplateParams; 131 if (ParseTemplateParameters(Depth, TemplateParams, LAngleLoc, 132 RAngleLoc)) { 133 // Skip until the semi-colon or a }. 134 SkipUntil(tok::r_brace, true, true); 135 if (Tok.is(tok::semi)) 136 ConsumeToken(); 137 return 0; 138 } 139 140 ParamLists.push_back( 141 Actions.ActOnTemplateParameterList(Depth, ExportLoc, 142 TemplateLoc, LAngleLoc, 143 TemplateParams.data(), 144 TemplateParams.size(), RAngleLoc)); 145 146 if (!TemplateParams.empty()) { 147 isSpecialization = false; 148 ++Depth; 149 } else { 150 LastParamListWasEmpty = true; 151 } 152 } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template)); 153 154 // Parse the actual template declaration. 155 return ParseSingleDeclarationAfterTemplate(Context, 156 ParsedTemplateInfo(&ParamLists, 157 isSpecialization, 158 LastParamListWasEmpty), 159 ParsingTemplateParams, 160 DeclEnd, AS); 161} 162 163/// \brief Parse a single declaration that declares a template, 164/// template specialization, or explicit instantiation of a template. 165/// 166/// \param TemplateParams if non-NULL, the template parameter lists 167/// that preceded this declaration. In this case, the declaration is a 168/// template declaration, out-of-line definition of a template, or an 169/// explicit template specialization. When NULL, the declaration is an 170/// explicit template instantiation. 171/// 172/// \param TemplateLoc when TemplateParams is NULL, the location of 173/// the 'template' keyword that indicates that we have an explicit 174/// template instantiation. 175/// 176/// \param DeclEnd will receive the source location of the last token 177/// within this declaration. 178/// 179/// \param AS the access specifier associated with this 180/// declaration. Will be AS_none for namespace-scope declarations. 181/// 182/// \returns the new declaration. 183Decl * 184Parser::ParseSingleDeclarationAfterTemplate( 185 unsigned Context, 186 const ParsedTemplateInfo &TemplateInfo, 187 ParsingDeclRAIIObject &DiagsFromTParams, 188 SourceLocation &DeclEnd, 189 AccessSpecifier AS) { 190 assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate && 191 "Template information required"); 192 193 if (Context == Declarator::MemberContext) { 194 // We are parsing a member template. 195 ParseCXXClassMemberDeclaration(AS, TemplateInfo, &DiagsFromTParams); 196 return 0; 197 } 198 199 ParsedAttributesWithRange prefixAttrs; 200 MaybeParseCXX0XAttributes(prefixAttrs); 201 202 if (Tok.is(tok::kw_using)) 203 return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd, 204 prefixAttrs); 205 206 // Parse the declaration specifiers, stealing the accumulated 207 // diagnostics from the template parameters. 208 ParsingDeclSpec DS(DiagsFromTParams); 209 210 DS.takeAttributesFrom(prefixAttrs); 211 212 ParseDeclarationSpecifiers(DS, TemplateInfo, AS, 213 getDeclSpecContextFromDeclaratorContext(Context)); 214 215 if (Tok.is(tok::semi)) { 216 DeclEnd = ConsumeToken(); 217 Decl *Decl = Actions.ParsedFreeStandingDeclSpec(getCurScope(), AS, DS); 218 DS.complete(Decl); 219 return Decl; 220 } 221 222 // Parse the declarator. 223 ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context); 224 ParseDeclarator(DeclaratorInfo); 225 // Error parsing the declarator? 226 if (!DeclaratorInfo.hasName()) { 227 // If so, skip until the semi-colon or a }. 228 SkipUntil(tok::r_brace, true, true); 229 if (Tok.is(tok::semi)) 230 ConsumeToken(); 231 return 0; 232 } 233 234 // If we have a declaration or declarator list, handle it. 235 if (isDeclarationAfterDeclarator()) { 236 // Parse this declaration. 237 Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo, 238 TemplateInfo); 239 240 if (Tok.is(tok::comma)) { 241 Diag(Tok, diag::err_multiple_template_declarators) 242 << (int)TemplateInfo.Kind; 243 SkipUntil(tok::semi, true, false); 244 return ThisDecl; 245 } 246 247 // Eat the semi colon after the declaration. 248 ExpectAndConsume(tok::semi, diag::err_expected_semi_declaration); 249 DeclaratorInfo.complete(ThisDecl); 250 return ThisDecl; 251 } 252 253 if (DeclaratorInfo.isFunctionDeclarator() && 254 isStartOfFunctionDefinition(DeclaratorInfo)) { 255 if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) { 256 Diag(Tok, diag::err_function_declared_typedef); 257 258 if (Tok.is(tok::l_brace)) { 259 // This recovery skips the entire function body. It would be nice 260 // to simply call ParseFunctionDefinition() below, however Sema 261 // assumes the declarator represents a function, not a typedef. 262 ConsumeBrace(); 263 SkipUntil(tok::r_brace, true); 264 } else { 265 SkipUntil(tok::semi); 266 } 267 return 0; 268 } 269 return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo); 270 } 271 272 if (DeclaratorInfo.isFunctionDeclarator()) 273 Diag(Tok, diag::err_expected_fn_body); 274 else 275 Diag(Tok, diag::err_invalid_token_after_toplevel_declarator); 276 SkipUntil(tok::semi); 277 return 0; 278} 279 280/// ParseTemplateParameters - Parses a template-parameter-list enclosed in 281/// angle brackets. Depth is the depth of this template-parameter-list, which 282/// is the number of template headers directly enclosing this template header. 283/// TemplateParams is the current list of template parameters we're building. 284/// The template parameter we parse will be added to this list. LAngleLoc and 285/// RAngleLoc will receive the positions of the '<' and '>', respectively, 286/// that enclose this template parameter list. 287/// 288/// \returns true if an error occurred, false otherwise. 289bool Parser::ParseTemplateParameters(unsigned Depth, 290 llvm::SmallVectorImpl<Decl*> &TemplateParams, 291 SourceLocation &LAngleLoc, 292 SourceLocation &RAngleLoc) { 293 // Get the template parameter list. 294 if (!Tok.is(tok::less)) { 295 Diag(Tok.getLocation(), diag::err_expected_less_after) << "template"; 296 return true; 297 } 298 LAngleLoc = ConsumeToken(); 299 300 // Try to parse the template parameter list. 301 if (Tok.is(tok::greater)) 302 RAngleLoc = ConsumeToken(); 303 else if (ParseTemplateParameterList(Depth, TemplateParams)) { 304 if (!Tok.is(tok::greater)) { 305 Diag(Tok.getLocation(), diag::err_expected_greater); 306 return true; 307 } 308 RAngleLoc = ConsumeToken(); 309 } 310 return false; 311} 312 313/// ParseTemplateParameterList - Parse a template parameter list. If 314/// the parsing fails badly (i.e., closing bracket was left out), this 315/// will try to put the token stream in a reasonable position (closing 316/// a statement, etc.) and return false. 317/// 318/// template-parameter-list: [C++ temp] 319/// template-parameter 320/// template-parameter-list ',' template-parameter 321bool 322Parser::ParseTemplateParameterList(unsigned Depth, 323 llvm::SmallVectorImpl<Decl*> &TemplateParams) { 324 while (1) { 325 if (Decl *TmpParam 326 = ParseTemplateParameter(Depth, TemplateParams.size())) { 327 TemplateParams.push_back(TmpParam); 328 } else { 329 // If we failed to parse a template parameter, skip until we find 330 // a comma or closing brace. 331 SkipUntil(tok::comma, tok::greater, true, true); 332 } 333 334 // Did we find a comma or the end of the template parmeter list? 335 if (Tok.is(tok::comma)) { 336 ConsumeToken(); 337 } else if (Tok.is(tok::greater)) { 338 // Don't consume this... that's done by template parser. 339 break; 340 } else { 341 // Somebody probably forgot to close the template. Skip ahead and 342 // try to get out of the expression. This error is currently 343 // subsumed by whatever goes on in ParseTemplateParameter. 344 // TODO: This could match >>, and it would be nice to avoid those 345 // silly errors with template <vec<T>>. 346 Diag(Tok.getLocation(), diag::err_expected_comma_greater); 347 SkipUntil(tok::greater, true, true); 348 return false; 349 } 350 } 351 return true; 352} 353 354/// \brief Determine whether the parser is at the start of a template 355/// type parameter. 356bool Parser::isStartOfTemplateTypeParameter() { 357 if (Tok.is(tok::kw_class)) { 358 // "class" may be the start of an elaborated-type-specifier or a 359 // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter. 360 switch (NextToken().getKind()) { 361 case tok::equal: 362 case tok::comma: 363 case tok::greater: 364 case tok::greatergreater: 365 case tok::ellipsis: 366 return true; 367 368 case tok::identifier: 369 // This may be either a type-parameter or an elaborated-type-specifier. 370 // We have to look further. 371 break; 372 373 default: 374 return false; 375 } 376 377 switch (GetLookAheadToken(2).getKind()) { 378 case tok::equal: 379 case tok::comma: 380 case tok::greater: 381 case tok::greatergreater: 382 return true; 383 384 default: 385 return false; 386 } 387 } 388 389 if (Tok.isNot(tok::kw_typename)) 390 return false; 391 392 // C++ [temp.param]p2: 393 // There is no semantic difference between class and typename in a 394 // template-parameter. typename followed by an unqualified-id 395 // names a template type parameter. typename followed by a 396 // qualified-id denotes the type in a non-type 397 // parameter-declaration. 398 Token Next = NextToken(); 399 400 // If we have an identifier, skip over it. 401 if (Next.getKind() == tok::identifier) 402 Next = GetLookAheadToken(2); 403 404 switch (Next.getKind()) { 405 case tok::equal: 406 case tok::comma: 407 case tok::greater: 408 case tok::greatergreater: 409 case tok::ellipsis: 410 return true; 411 412 default: 413 return false; 414 } 415} 416 417/// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]). 418/// 419/// template-parameter: [C++ temp.param] 420/// type-parameter 421/// parameter-declaration 422/// 423/// type-parameter: (see below) 424/// 'class' ...[opt] identifier[opt] 425/// 'class' identifier[opt] '=' type-id 426/// 'typename' ...[opt] identifier[opt] 427/// 'typename' identifier[opt] '=' type-id 428/// 'template' '<' template-parameter-list '>' 429/// 'class' ...[opt] identifier[opt] 430/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] 431/// = id-expression 432Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { 433 if (isStartOfTemplateTypeParameter()) 434 return ParseTypeParameter(Depth, Position); 435 436 if (Tok.is(tok::kw_template)) 437 return ParseTemplateTemplateParameter(Depth, Position); 438 439 // If it's none of the above, then it must be a parameter declaration. 440 // NOTE: This will pick up errors in the closure of the template parameter 441 // list (e.g., template < ; Check here to implement >> style closures. 442 return ParseNonTypeTemplateParameter(Depth, Position); 443} 444 445/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]). 446/// Other kinds of template parameters are parsed in 447/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter. 448/// 449/// type-parameter: [C++ temp.param] 450/// 'class' ...[opt][C++0x] identifier[opt] 451/// 'class' identifier[opt] '=' type-id 452/// 'typename' ...[opt][C++0x] identifier[opt] 453/// 'typename' identifier[opt] '=' type-id 454Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) { 455 assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) && 456 "A type-parameter starts with 'class' or 'typename'"); 457 458 // Consume the 'class' or 'typename' keyword. 459 bool TypenameKeyword = Tok.is(tok::kw_typename); 460 SourceLocation KeyLoc = ConsumeToken(); 461 462 // Grab the ellipsis (if given). 463 bool Ellipsis = false; 464 SourceLocation EllipsisLoc; 465 if (Tok.is(tok::ellipsis)) { 466 Ellipsis = true; 467 EllipsisLoc = ConsumeToken(); 468 469 if (!getLang().CPlusPlus0x) 470 Diag(EllipsisLoc, diag::ext_variadic_templates); 471 } 472 473 // Grab the template parameter name (if given) 474 SourceLocation NameLoc; 475 IdentifierInfo* ParamName = 0; 476 if (Tok.is(tok::identifier)) { 477 ParamName = Tok.getIdentifierInfo(); 478 NameLoc = ConsumeToken(); 479 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || 480 Tok.is(tok::greater)) { 481 // Unnamed template parameter. Don't have to do anything here, just 482 // don't consume this token. 483 } else { 484 Diag(Tok.getLocation(), diag::err_expected_ident); 485 return 0; 486 } 487 488 // Grab a default argument (if available). 489 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 490 // we introduce the type parameter into the local scope. 491 SourceLocation EqualLoc; 492 ParsedType DefaultArg; 493 if (Tok.is(tok::equal)) { 494 EqualLoc = ConsumeToken(); 495 DefaultArg = ParseTypeName().get(); 496 } 497 498 return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, Ellipsis, 499 EllipsisLoc, KeyLoc, ParamName, NameLoc, 500 Depth, Position, EqualLoc, DefaultArg); 501} 502 503/// ParseTemplateTemplateParameter - Handle the parsing of template 504/// template parameters. 505/// 506/// type-parameter: [C++ temp.param] 507/// 'template' '<' template-parameter-list '>' 'class' 508/// ...[opt] identifier[opt] 509/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] 510/// = id-expression 511Decl * 512Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { 513 assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); 514 515 // Handle the template <...> part. 516 SourceLocation TemplateLoc = ConsumeToken(); 517 llvm::SmallVector<Decl*,8> TemplateParams; 518 SourceLocation LAngleLoc, RAngleLoc; 519 { 520 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 521 if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, 522 RAngleLoc)) { 523 return 0; 524 } 525 } 526 527 // Generate a meaningful error if the user forgot to put class before the 528 // identifier, comma, or greater. 529 if (!Tok.is(tok::kw_class)) { 530 Diag(Tok.getLocation(), diag::err_expected_class_before) 531 << PP.getSpelling(Tok); 532 return 0; 533 } 534 ConsumeToken(); 535 536 // Parse the ellipsis, if given. 537 SourceLocation EllipsisLoc; 538 if (Tok.is(tok::ellipsis)) { 539 EllipsisLoc = ConsumeToken(); 540 541 if (!getLang().CPlusPlus0x) 542 Diag(EllipsisLoc, diag::ext_variadic_templates); 543 } 544 545 // Get the identifier, if given. 546 SourceLocation NameLoc; 547 IdentifierInfo* ParamName = 0; 548 if (Tok.is(tok::identifier)) { 549 ParamName = Tok.getIdentifierInfo(); 550 NameLoc = ConsumeToken(); 551 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater)) { 552 // Unnamed template parameter. Don't have to do anything here, just 553 // don't consume this token. 554 } else { 555 Diag(Tok.getLocation(), diag::err_expected_ident); 556 return 0; 557 } 558 559 TemplateParamsTy *ParamList = 560 Actions.ActOnTemplateParameterList(Depth, SourceLocation(), 561 TemplateLoc, LAngleLoc, 562 TemplateParams.data(), 563 TemplateParams.size(), 564 RAngleLoc); 565 566 // Grab a default argument (if available). 567 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 568 // we introduce the template parameter into the local scope. 569 SourceLocation EqualLoc; 570 ParsedTemplateArgument DefaultArg; 571 if (Tok.is(tok::equal)) { 572 EqualLoc = ConsumeToken(); 573 DefaultArg = ParseTemplateTemplateArgument(); 574 if (DefaultArg.isInvalid()) { 575 Diag(Tok.getLocation(), 576 diag::err_default_template_template_parameter_not_template); 577 static const tok::TokenKind EndToks[] = { 578 tok::comma, tok::greater, tok::greatergreater 579 }; 580 SkipUntil(EndToks, 3, true, true); 581 } 582 } 583 584 return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc, 585 ParamList, EllipsisLoc, 586 ParamName, NameLoc, Depth, 587 Position, EqualLoc, DefaultArg); 588} 589 590/// ParseNonTypeTemplateParameter - Handle the parsing of non-type 591/// template parameters (e.g., in "template<int Size> class array;"). 592/// 593/// template-parameter: 594/// ... 595/// parameter-declaration 596Decl * 597Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { 598 // Parse the declaration-specifiers (i.e., the type). 599 // FIXME: The type should probably be restricted in some way... Not all 600 // declarators (parts of declarators?) are accepted for parameters. 601 DeclSpec DS; 602 ParseDeclarationSpecifiers(DS); 603 604 // Parse this as a typename. 605 Declarator ParamDecl(DS, Declarator::TemplateParamContext); 606 ParseDeclarator(ParamDecl); 607 if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) { 608 // This probably shouldn't happen - and it's more of a Sema thing, but 609 // basically we didn't parse the type name because we couldn't associate 610 // it with an AST node. we should just skip to the comma or greater. 611 // TODO: This is currently a placeholder for some kind of Sema Error. 612 Diag(Tok.getLocation(), diag::err_parse_error); 613 SkipUntil(tok::comma, tok::greater, true, true); 614 return 0; 615 } 616 617 // If there is a default value, parse it. 618 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 619 // we introduce the template parameter into the local scope. 620 SourceLocation EqualLoc; 621 ExprResult DefaultArg; 622 if (Tok.is(tok::equal)) { 623 EqualLoc = ConsumeToken(); 624 625 // C++ [temp.param]p15: 626 // When parsing a default template-argument for a non-type 627 // template-parameter, the first non-nested > is taken as the 628 // end of the template-parameter-list rather than a greater-than 629 // operator. 630 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 631 632 DefaultArg = ParseAssignmentExpression(); 633 if (DefaultArg.isInvalid()) 634 SkipUntil(tok::comma, tok::greater, true, true); 635 } 636 637 // Create the parameter. 638 return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl, 639 Depth, Position, EqualLoc, 640 DefaultArg.take()); 641} 642 643/// \brief Parses a template-id that after the template name has 644/// already been parsed. 645/// 646/// This routine takes care of parsing the enclosed template argument 647/// list ('<' template-parameter-list [opt] '>') and placing the 648/// results into a form that can be transferred to semantic analysis. 649/// 650/// \param Template the template declaration produced by isTemplateName 651/// 652/// \param TemplateNameLoc the source location of the template name 653/// 654/// \param SS if non-NULL, the nested-name-specifier preceding the 655/// template name. 656/// 657/// \param ConsumeLastToken if true, then we will consume the last 658/// token that forms the template-id. Otherwise, we will leave the 659/// last token in the stream (e.g., so that it can be replaced with an 660/// annotation token). 661bool 662Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template, 663 SourceLocation TemplateNameLoc, 664 const CXXScopeSpec *SS, 665 bool ConsumeLastToken, 666 SourceLocation &LAngleLoc, 667 TemplateArgList &TemplateArgs, 668 SourceLocation &RAngleLoc) { 669 assert(Tok.is(tok::less) && "Must have already parsed the template-name"); 670 671 // Consume the '<'. 672 LAngleLoc = ConsumeToken(); 673 674 // Parse the optional template-argument-list. 675 bool Invalid = false; 676 { 677 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 678 if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) 679 Invalid = ParseTemplateArgumentList(TemplateArgs); 680 681 if (Invalid) { 682 // Try to find the closing '>'. 683 SkipUntil(tok::greater, true, !ConsumeLastToken); 684 685 return true; 686 } 687 } 688 689 if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) { 690 Diag(Tok.getLocation(), diag::err_expected_greater); 691 return true; 692 } 693 694 // Determine the location of the '>' or '>>'. Only consume this 695 // token if the caller asked us to. 696 RAngleLoc = Tok.getLocation(); 697 698 if (Tok.is(tok::greatergreater)) { 699 if (!getLang().CPlusPlus0x) { 700 const char *ReplaceStr = "> >"; 701 if (NextToken().is(tok::greater) || NextToken().is(tok::greatergreater)) 702 ReplaceStr = "> > "; 703 704 Diag(Tok.getLocation(), diag::err_two_right_angle_brackets_need_space) 705 << FixItHint::CreateReplacement( 706 SourceRange(Tok.getLocation()), ReplaceStr); 707 } 708 709 Tok.setKind(tok::greater); 710 if (!ConsumeLastToken) { 711 // Since we're not supposed to consume the '>>' token, we need 712 // to insert a second '>' token after the first. 713 PP.EnterToken(Tok); 714 } 715 } else if (ConsumeLastToken) 716 ConsumeToken(); 717 718 return false; 719} 720 721/// \brief Replace the tokens that form a simple-template-id with an 722/// annotation token containing the complete template-id. 723/// 724/// The first token in the stream must be the name of a template that 725/// is followed by a '<'. This routine will parse the complete 726/// simple-template-id and replace the tokens with a single annotation 727/// token with one of two different kinds: if the template-id names a 728/// type (and \p AllowTypeAnnotation is true), the annotation token is 729/// a type annotation that includes the optional nested-name-specifier 730/// (\p SS). Otherwise, the annotation token is a template-id 731/// annotation that does not include the optional 732/// nested-name-specifier. 733/// 734/// \param Template the declaration of the template named by the first 735/// token (an identifier), as returned from \c Action::isTemplateName(). 736/// 737/// \param TemplateNameKind the kind of template that \p Template 738/// refers to, as returned from \c Action::isTemplateName(). 739/// 740/// \param SS if non-NULL, the nested-name-specifier that precedes 741/// this template name. 742/// 743/// \param TemplateKWLoc if valid, specifies that this template-id 744/// annotation was preceded by the 'template' keyword and gives the 745/// location of that keyword. If invalid (the default), then this 746/// template-id was not preceded by a 'template' keyword. 747/// 748/// \param AllowTypeAnnotation if true (the default), then a 749/// simple-template-id that refers to a class template, template 750/// template parameter, or other template that produces a type will be 751/// replaced with a type annotation token. Otherwise, the 752/// simple-template-id is always replaced with a template-id 753/// annotation token. 754/// 755/// If an unrecoverable parse error occurs and no annotation token can be 756/// formed, this function returns true. 757/// 758bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK, 759 const CXXScopeSpec *SS, 760 UnqualifiedId &TemplateName, 761 SourceLocation TemplateKWLoc, 762 bool AllowTypeAnnotation) { 763 assert(getLang().CPlusPlus && "Can only annotate template-ids in C++"); 764 assert(Template && Tok.is(tok::less) && 765 "Parser isn't at the beginning of a template-id"); 766 767 // Consume the template-name. 768 SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin(); 769 770 // Parse the enclosed template argument list. 771 SourceLocation LAngleLoc, RAngleLoc; 772 TemplateArgList TemplateArgs; 773 bool Invalid = ParseTemplateIdAfterTemplateName(Template, 774 TemplateNameLoc, 775 SS, false, LAngleLoc, 776 TemplateArgs, 777 RAngleLoc); 778 779 if (Invalid) { 780 // If we failed to parse the template ID but skipped ahead to a >, we're not 781 // going to be able to form a token annotation. Eat the '>' if present. 782 if (Tok.is(tok::greater)) 783 ConsumeToken(); 784 return true; 785 } 786 787 ASTTemplateArgsPtr TemplateArgsPtr(Actions, TemplateArgs.data(), 788 TemplateArgs.size()); 789 790 // Build the annotation token. 791 if (TNK == TNK_Type_template && AllowTypeAnnotation) { 792 TypeResult Type 793 = Actions.ActOnTemplateIdType(Template, TemplateNameLoc, 794 LAngleLoc, TemplateArgsPtr, 795 RAngleLoc); 796 if (Type.isInvalid()) { 797 // If we failed to parse the template ID but skipped ahead to a >, we're not 798 // going to be able to form a token annotation. Eat the '>' if present. 799 if (Tok.is(tok::greater)) 800 ConsumeToken(); 801 return true; 802 } 803 804 Tok.setKind(tok::annot_typename); 805 setTypeAnnotation(Tok, Type.get()); 806 if (SS && SS->isNotEmpty()) 807 Tok.setLocation(SS->getBeginLoc()); 808 else if (TemplateKWLoc.isValid()) 809 Tok.setLocation(TemplateKWLoc); 810 else 811 Tok.setLocation(TemplateNameLoc); 812 } else { 813 // Build a template-id annotation token that can be processed 814 // later. 815 Tok.setKind(tok::annot_template_id); 816 TemplateIdAnnotation *TemplateId 817 = TemplateIdAnnotation::Allocate(TemplateArgs.size()); 818 TemplateId->TemplateNameLoc = TemplateNameLoc; 819 if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) { 820 TemplateId->Name = TemplateName.Identifier; 821 TemplateId->Operator = OO_None; 822 } else { 823 TemplateId->Name = 0; 824 TemplateId->Operator = TemplateName.OperatorFunctionId.Operator; 825 } 826 TemplateId->Template = Template; 827 TemplateId->Kind = TNK; 828 TemplateId->LAngleLoc = LAngleLoc; 829 TemplateId->RAngleLoc = RAngleLoc; 830 ParsedTemplateArgument *Args = TemplateId->getTemplateArgs(); 831 for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) 832 Args[Arg] = ParsedTemplateArgument(TemplateArgs[Arg]); 833 Tok.setAnnotationValue(TemplateId); 834 if (TemplateKWLoc.isValid()) 835 Tok.setLocation(TemplateKWLoc); 836 else 837 Tok.setLocation(TemplateNameLoc); 838 839 TemplateArgsPtr.release(); 840 } 841 842 // Common fields for the annotation token 843 Tok.setAnnotationEndLoc(RAngleLoc); 844 845 // In case the tokens were cached, have Preprocessor replace them with the 846 // annotation token. 847 PP.AnnotateCachedTokens(Tok); 848 return false; 849} 850 851/// \brief Replaces a template-id annotation token with a type 852/// annotation token. 853/// 854/// If there was a failure when forming the type from the template-id, 855/// a type annotation token will still be created, but will have a 856/// NULL type pointer to signify an error. 857void Parser::AnnotateTemplateIdTokenAsType(const CXXScopeSpec *SS) { 858 assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens"); 859 860 TemplateIdAnnotation *TemplateId 861 = static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue()); 862 assert((TemplateId->Kind == TNK_Type_template || 863 TemplateId->Kind == TNK_Dependent_template_name) && 864 "Only works for type and dependent templates"); 865 866 ASTTemplateArgsPtr TemplateArgsPtr(Actions, 867 TemplateId->getTemplateArgs(), 868 TemplateId->NumArgs); 869 870 TypeResult Type 871 = Actions.ActOnTemplateIdType(TemplateId->Template, 872 TemplateId->TemplateNameLoc, 873 TemplateId->LAngleLoc, 874 TemplateArgsPtr, 875 TemplateId->RAngleLoc); 876 // Create the new "type" annotation token. 877 Tok.setKind(tok::annot_typename); 878 setTypeAnnotation(Tok, Type.isInvalid() ? ParsedType() : Type.get()); 879 if (SS && SS->isNotEmpty()) // it was a C++ qualified type name. 880 Tok.setLocation(SS->getBeginLoc()); 881 // End location stays the same 882 883 // Replace the template-id annotation token, and possible the scope-specifier 884 // that precedes it, with the typename annotation token. 885 PP.AnnotateCachedTokens(Tok); 886 TemplateId->Destroy(); 887} 888 889/// \brief Determine whether the given token can end a template argument. 890static bool isEndOfTemplateArgument(Token Tok) { 891 return Tok.is(tok::comma) || Tok.is(tok::greater) || 892 Tok.is(tok::greatergreater); 893} 894 895/// \brief Parse a C++ template template argument. 896ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() { 897 if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) && 898 !Tok.is(tok::annot_cxxscope)) 899 return ParsedTemplateArgument(); 900 901 // C++0x [temp.arg.template]p1: 902 // A template-argument for a template template-parameter shall be the name 903 // of a class template or a template alias, expressed as id-expression. 904 // 905 // We parse an id-expression that refers to a class template or template 906 // alias. The grammar we parse is: 907 // 908 // nested-name-specifier[opt] template[opt] identifier ...[opt] 909 // 910 // followed by a token that terminates a template argument, such as ',', 911 // '>', or (in some cases) '>>'. 912 CXXScopeSpec SS; // nested-name-specifier, if present 913 ParseOptionalCXXScopeSpecifier(SS, ParsedType(), 914 /*EnteringContext=*/false); 915 916 ParsedTemplateArgument Result; 917 SourceLocation EllipsisLoc; 918 if (SS.isSet() && Tok.is(tok::kw_template)) { 919 // Parse the optional 'template' keyword following the 920 // nested-name-specifier. 921 SourceLocation TemplateLoc = ConsumeToken(); 922 923 if (Tok.is(tok::identifier)) { 924 // We appear to have a dependent template name. 925 UnqualifiedId Name; 926 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 927 ConsumeToken(); // the identifier 928 929 // Parse the ellipsis. 930 if (Tok.is(tok::ellipsis)) 931 EllipsisLoc = ConsumeToken(); 932 933 // If the next token signals the end of a template argument, 934 // then we have a dependent template name that could be a template 935 // template argument. 936 TemplateTy Template; 937 if (isEndOfTemplateArgument(Tok) && 938 Actions.ActOnDependentTemplateName(getCurScope(), TemplateLoc, 939 SS, Name, 940 /*ObjectType=*/ ParsedType(), 941 /*EnteringContext=*/false, 942 Template)) 943 Result = ParsedTemplateArgument(SS, Template, Name.StartLocation); 944 } 945 } else if (Tok.is(tok::identifier)) { 946 // We may have a (non-dependent) template name. 947 TemplateTy Template; 948 UnqualifiedId Name; 949 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 950 ConsumeToken(); // the identifier 951 952 // Parse the ellipsis. 953 if (Tok.is(tok::ellipsis)) 954 EllipsisLoc = ConsumeToken(); 955 956 if (isEndOfTemplateArgument(Tok)) { 957 bool MemberOfUnknownSpecialization; 958 TemplateNameKind TNK = Actions.isTemplateName(getCurScope(), SS, 959 /*hasTemplateKeyword=*/false, 960 Name, 961 /*ObjectType=*/ ParsedType(), 962 /*EnteringContext=*/false, 963 Template, 964 MemberOfUnknownSpecialization); 965 if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) { 966 // We have an id-expression that refers to a class template or 967 // (C++0x) template alias. 968 Result = ParsedTemplateArgument(SS, Template, Name.StartLocation); 969 } 970 } 971 } 972 973 // If this is a pack expansion, build it as such. 974 if (EllipsisLoc.isValid() && !Result.isInvalid()) 975 Result = Actions.ActOnPackExpansion(Result, EllipsisLoc); 976 977 return Result; 978} 979 980/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). 981/// 982/// template-argument: [C++ 14.2] 983/// constant-expression 984/// type-id 985/// id-expression 986ParsedTemplateArgument Parser::ParseTemplateArgument() { 987 // C++ [temp.arg]p2: 988 // In a template-argument, an ambiguity between a type-id and an 989 // expression is resolved to a type-id, regardless of the form of 990 // the corresponding template-parameter. 991 // 992 // Therefore, we initially try to parse a type-id. 993 if (isCXXTypeId(TypeIdAsTemplateArgument)) { 994 SourceLocation Loc = Tok.getLocation(); 995 TypeResult TypeArg = ParseTypeName(/*Range=*/0, 996 Declarator::TemplateTypeArgContext); 997 if (TypeArg.isInvalid()) 998 return ParsedTemplateArgument(); 999 1000 return ParsedTemplateArgument(ParsedTemplateArgument::Type, 1001 TypeArg.get().getAsOpaquePtr(), 1002 Loc); 1003 } 1004 1005 // Try to parse a template template argument. 1006 { 1007 TentativeParsingAction TPA(*this); 1008 1009 ParsedTemplateArgument TemplateTemplateArgument 1010 = ParseTemplateTemplateArgument(); 1011 if (!TemplateTemplateArgument.isInvalid()) { 1012 TPA.Commit(); 1013 return TemplateTemplateArgument; 1014 } 1015 1016 // Revert this tentative parse to parse a non-type template argument. 1017 TPA.Revert(); 1018 } 1019 1020 // Parse a non-type template argument. 1021 SourceLocation Loc = Tok.getLocation(); 1022 ExprResult ExprArg = ParseConstantExpression(); 1023 if (ExprArg.isInvalid() || !ExprArg.get()) 1024 return ParsedTemplateArgument(); 1025 1026 return ParsedTemplateArgument(ParsedTemplateArgument::NonType, 1027 ExprArg.release(), Loc); 1028} 1029 1030/// \brief Determine whether the current tokens can only be parsed as a 1031/// template argument list (starting with the '<') and never as a '<' 1032/// expression. 1033bool Parser::IsTemplateArgumentList(unsigned Skip) { 1034 struct AlwaysRevertAction : TentativeParsingAction { 1035 AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { } 1036 ~AlwaysRevertAction() { Revert(); } 1037 } Tentative(*this); 1038 1039 while (Skip) { 1040 ConsumeToken(); 1041 --Skip; 1042 } 1043 1044 // '<' 1045 if (!Tok.is(tok::less)) 1046 return false; 1047 ConsumeToken(); 1048 1049 // An empty template argument list. 1050 if (Tok.is(tok::greater)) 1051 return true; 1052 1053 // See whether we have declaration specifiers, which indicate a type. 1054 while (isCXXDeclarationSpecifier() == TPResult::True()) 1055 ConsumeToken(); 1056 1057 // If we have a '>' or a ',' then this is a template argument list. 1058 return Tok.is(tok::greater) || Tok.is(tok::comma); 1059} 1060 1061/// ParseTemplateArgumentList - Parse a C++ template-argument-list 1062/// (C++ [temp.names]). Returns true if there was an error. 1063/// 1064/// template-argument-list: [C++ 14.2] 1065/// template-argument 1066/// template-argument-list ',' template-argument 1067bool 1068Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) { 1069 while (true) { 1070 ParsedTemplateArgument Arg = ParseTemplateArgument(); 1071 if (Tok.is(tok::ellipsis)) { 1072 SourceLocation EllipsisLoc = ConsumeToken(); 1073 Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc); 1074 } 1075 1076 if (Arg.isInvalid()) { 1077 SkipUntil(tok::comma, tok::greater, true, true); 1078 return true; 1079 } 1080 1081 // Save this template argument. 1082 TemplateArgs.push_back(Arg); 1083 1084 // If the next token is a comma, consume it and keep reading 1085 // arguments. 1086 if (Tok.isNot(tok::comma)) break; 1087 1088 // Consume the comma. 1089 ConsumeToken(); 1090 } 1091 1092 return false; 1093} 1094 1095/// \brief Parse a C++ explicit template instantiation 1096/// (C++ [temp.explicit]). 1097/// 1098/// explicit-instantiation: 1099/// 'extern' [opt] 'template' declaration 1100/// 1101/// Note that the 'extern' is a GNU extension and C++0x feature. 1102Decl *Parser::ParseExplicitInstantiation(SourceLocation ExternLoc, 1103 SourceLocation TemplateLoc, 1104 SourceLocation &DeclEnd) { 1105 // This isn't really required here. 1106 ParsingDeclRAIIObject ParsingTemplateParams(*this); 1107 1108 return ParseSingleDeclarationAfterTemplate(Declarator::FileContext, 1109 ParsedTemplateInfo(ExternLoc, 1110 TemplateLoc), 1111 ParsingTemplateParams, 1112 DeclEnd, AS_none); 1113} 1114 1115SourceRange Parser::ParsedTemplateInfo::getSourceRange() const { 1116 if (TemplateParams) 1117 return getTemplateParamsRange(TemplateParams->data(), 1118 TemplateParams->size()); 1119 1120 SourceRange R(TemplateLoc); 1121 if (ExternLoc.isValid()) 1122 R.setBegin(ExternLoc); 1123 return R; 1124} 1125