ParseTemplate.cpp revision 7f040a9d817cd1c72b565e92abff473510bf9e1d
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 DS.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][C++0x] identifier[opt] 425/// 'class' identifier[opt] '=' type-id 426/// 'typename' ...[opt][C++0x] identifier[opt] 427/// 'typename' identifier[opt] '=' type-id 428/// 'template' ...[opt][C++0x] '<' template-parameter-list '>' 'class' identifier[opt] 429/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression 430Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { 431 if (isStartOfTemplateTypeParameter()) 432 return ParseTypeParameter(Depth, Position); 433 434 if (Tok.is(tok::kw_template)) 435 return ParseTemplateTemplateParameter(Depth, Position); 436 437 // If it's none of the above, then it must be a parameter declaration. 438 // NOTE: This will pick up errors in the closure of the template parameter 439 // list (e.g., template < ; Check here to implement >> style closures. 440 return ParseNonTypeTemplateParameter(Depth, Position); 441} 442 443/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]). 444/// Other kinds of template parameters are parsed in 445/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter. 446/// 447/// type-parameter: [C++ temp.param] 448/// 'class' ...[opt][C++0x] identifier[opt] 449/// 'class' identifier[opt] '=' type-id 450/// 'typename' ...[opt][C++0x] identifier[opt] 451/// 'typename' identifier[opt] '=' type-id 452Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) { 453 assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) && 454 "A type-parameter starts with 'class' or 'typename'"); 455 456 // Consume the 'class' or 'typename' keyword. 457 bool TypenameKeyword = Tok.is(tok::kw_typename); 458 SourceLocation KeyLoc = ConsumeToken(); 459 460 // Grab the ellipsis (if given). 461 bool Ellipsis = false; 462 SourceLocation EllipsisLoc; 463 if (Tok.is(tok::ellipsis)) { 464 Ellipsis = true; 465 EllipsisLoc = ConsumeToken(); 466 467 if (!getLang().CPlusPlus0x) 468 Diag(EllipsisLoc, diag::err_variadic_templates); 469 } 470 471 // Grab the template parameter name (if given) 472 SourceLocation NameLoc; 473 IdentifierInfo* ParamName = 0; 474 if (Tok.is(tok::identifier)) { 475 ParamName = Tok.getIdentifierInfo(); 476 NameLoc = ConsumeToken(); 477 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || 478 Tok.is(tok::greater)) { 479 // Unnamed template parameter. Don't have to do anything here, just 480 // don't consume this token. 481 } else { 482 Diag(Tok.getLocation(), diag::err_expected_ident); 483 return 0; 484 } 485 486 // Grab a default argument (if available). 487 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 488 // we introduce the type parameter into the local scope. 489 SourceLocation EqualLoc; 490 ParsedType DefaultArg; 491 if (Tok.is(tok::equal)) { 492 EqualLoc = ConsumeToken(); 493 DefaultArg = ParseTypeName().get(); 494 } 495 496 return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, Ellipsis, 497 EllipsisLoc, KeyLoc, ParamName, NameLoc, 498 Depth, Position, EqualLoc, DefaultArg); 499} 500 501/// ParseTemplateTemplateParameter - Handle the parsing of template 502/// template parameters. 503/// 504/// type-parameter: [C++ temp.param] 505/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] 506/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression 507Decl * 508Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { 509 assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); 510 511 // Handle the template <...> part. 512 SourceLocation TemplateLoc = ConsumeToken(); 513 llvm::SmallVector<Decl*,8> TemplateParams; 514 SourceLocation LAngleLoc, RAngleLoc; 515 { 516 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 517 if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, 518 RAngleLoc)) { 519 return 0; 520 } 521 } 522 523 // Generate a meaningful error if the user forgot to put class before the 524 // identifier, comma, or greater. 525 if (!Tok.is(tok::kw_class)) { 526 Diag(Tok.getLocation(), diag::err_expected_class_before) 527 << PP.getSpelling(Tok); 528 return 0; 529 } 530 SourceLocation ClassLoc = ConsumeToken(); 531 532 // Get the identifier, if given. 533 SourceLocation NameLoc; 534 IdentifierInfo* ParamName = 0; 535 if (Tok.is(tok::identifier)) { 536 ParamName = Tok.getIdentifierInfo(); 537 NameLoc = ConsumeToken(); 538 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater)) { 539 // Unnamed template parameter. Don't have to do anything here, just 540 // don't consume this token. 541 } else { 542 Diag(Tok.getLocation(), diag::err_expected_ident); 543 return 0; 544 } 545 546 TemplateParamsTy *ParamList = 547 Actions.ActOnTemplateParameterList(Depth, SourceLocation(), 548 TemplateLoc, LAngleLoc, 549 TemplateParams.data(), 550 TemplateParams.size(), 551 RAngleLoc); 552 553 // Grab a default argument (if available). 554 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 555 // we introduce the template parameter into the local scope. 556 SourceLocation EqualLoc; 557 ParsedTemplateArgument DefaultArg; 558 if (Tok.is(tok::equal)) { 559 EqualLoc = ConsumeToken(); 560 DefaultArg = ParseTemplateTemplateArgument(); 561 if (DefaultArg.isInvalid()) { 562 Diag(Tok.getLocation(), 563 diag::err_default_template_template_parameter_not_template); 564 static const tok::TokenKind EndToks[] = { 565 tok::comma, tok::greater, tok::greatergreater 566 }; 567 SkipUntil(EndToks, 3, true, true); 568 } 569 } 570 571 return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc, 572 ParamList, ParamName, 573 NameLoc, Depth, Position, 574 EqualLoc, DefaultArg); 575} 576 577/// ParseNonTypeTemplateParameter - Handle the parsing of non-type 578/// template parameters (e.g., in "template<int Size> class array;"). 579/// 580/// template-parameter: 581/// ... 582/// parameter-declaration 583Decl * 584Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { 585 SourceLocation StartLoc = Tok.getLocation(); 586 587 // Parse the declaration-specifiers (i.e., the type). 588 // FIXME: The type should probably be restricted in some way... Not all 589 // declarators (parts of declarators?) are accepted for parameters. 590 DeclSpec DS; 591 ParseDeclarationSpecifiers(DS); 592 593 // Parse this as a typename. 594 Declarator ParamDecl(DS, Declarator::TemplateParamContext); 595 ParseDeclarator(ParamDecl); 596 if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) { 597 // This probably shouldn't happen - and it's more of a Sema thing, but 598 // basically we didn't parse the type name because we couldn't associate 599 // it with an AST node. we should just skip to the comma or greater. 600 // TODO: This is currently a placeholder for some kind of Sema Error. 601 Diag(Tok.getLocation(), diag::err_parse_error); 602 SkipUntil(tok::comma, tok::greater, true, true); 603 return 0; 604 } 605 606 // If there is a default value, parse it. 607 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 608 // we introduce the template parameter into the local scope. 609 SourceLocation EqualLoc; 610 ExprResult DefaultArg; 611 if (Tok.is(tok::equal)) { 612 EqualLoc = ConsumeToken(); 613 614 // C++ [temp.param]p15: 615 // When parsing a default template-argument for a non-type 616 // template-parameter, the first non-nested > is taken as the 617 // end of the template-parameter-list rather than a greater-than 618 // operator. 619 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 620 621 DefaultArg = ParseAssignmentExpression(); 622 if (DefaultArg.isInvalid()) 623 SkipUntil(tok::comma, tok::greater, true, true); 624 } 625 626 // Create the parameter. 627 return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl, 628 Depth, Position, EqualLoc, 629 DefaultArg.take()); 630} 631 632/// \brief Parses a template-id that after the template name has 633/// already been parsed. 634/// 635/// This routine takes care of parsing the enclosed template argument 636/// list ('<' template-parameter-list [opt] '>') and placing the 637/// results into a form that can be transferred to semantic analysis. 638/// 639/// \param Template the template declaration produced by isTemplateName 640/// 641/// \param TemplateNameLoc the source location of the template name 642/// 643/// \param SS if non-NULL, the nested-name-specifier preceding the 644/// template name. 645/// 646/// \param ConsumeLastToken if true, then we will consume the last 647/// token that forms the template-id. Otherwise, we will leave the 648/// last token in the stream (e.g., so that it can be replaced with an 649/// annotation token). 650bool 651Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template, 652 SourceLocation TemplateNameLoc, 653 const CXXScopeSpec *SS, 654 bool ConsumeLastToken, 655 SourceLocation &LAngleLoc, 656 TemplateArgList &TemplateArgs, 657 SourceLocation &RAngleLoc) { 658 assert(Tok.is(tok::less) && "Must have already parsed the template-name"); 659 660 // Consume the '<'. 661 LAngleLoc = ConsumeToken(); 662 663 // Parse the optional template-argument-list. 664 bool Invalid = false; 665 { 666 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 667 if (Tok.isNot(tok::greater)) 668 Invalid = ParseTemplateArgumentList(TemplateArgs); 669 670 if (Invalid) { 671 // Try to find the closing '>'. 672 SkipUntil(tok::greater, true, !ConsumeLastToken); 673 674 return true; 675 } 676 } 677 678 if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) { 679 Diag(Tok.getLocation(), diag::err_expected_greater); 680 return true; 681 } 682 683 // Determine the location of the '>' or '>>'. Only consume this 684 // token if the caller asked us to. 685 RAngleLoc = Tok.getLocation(); 686 687 if (Tok.is(tok::greatergreater)) { 688 if (!getLang().CPlusPlus0x) { 689 const char *ReplaceStr = "> >"; 690 if (NextToken().is(tok::greater) || NextToken().is(tok::greatergreater)) 691 ReplaceStr = "> > "; 692 693 Diag(Tok.getLocation(), diag::err_two_right_angle_brackets_need_space) 694 << FixItHint::CreateReplacement( 695 SourceRange(Tok.getLocation()), ReplaceStr); 696 } 697 698 Tok.setKind(tok::greater); 699 if (!ConsumeLastToken) { 700 // Since we're not supposed to consume the '>>' token, we need 701 // to insert a second '>' token after the first. 702 PP.EnterToken(Tok); 703 } 704 } else if (ConsumeLastToken) 705 ConsumeToken(); 706 707 return false; 708} 709 710/// \brief Replace the tokens that form a simple-template-id with an 711/// annotation token containing the complete template-id. 712/// 713/// The first token in the stream must be the name of a template that 714/// is followed by a '<'. This routine will parse the complete 715/// simple-template-id and replace the tokens with a single annotation 716/// token with one of two different kinds: if the template-id names a 717/// type (and \p AllowTypeAnnotation is true), the annotation token is 718/// a type annotation that includes the optional nested-name-specifier 719/// (\p SS). Otherwise, the annotation token is a template-id 720/// annotation that does not include the optional 721/// nested-name-specifier. 722/// 723/// \param Template the declaration of the template named by the first 724/// token (an identifier), as returned from \c Action::isTemplateName(). 725/// 726/// \param TemplateNameKind the kind of template that \p Template 727/// refers to, as returned from \c Action::isTemplateName(). 728/// 729/// \param SS if non-NULL, the nested-name-specifier that precedes 730/// this template name. 731/// 732/// \param TemplateKWLoc if valid, specifies that this template-id 733/// annotation was preceded by the 'template' keyword and gives the 734/// location of that keyword. If invalid (the default), then this 735/// template-id was not preceded by a 'template' keyword. 736/// 737/// \param AllowTypeAnnotation if true (the default), then a 738/// simple-template-id that refers to a class template, template 739/// template parameter, or other template that produces a type will be 740/// replaced with a type annotation token. Otherwise, the 741/// simple-template-id is always replaced with a template-id 742/// annotation token. 743/// 744/// If an unrecoverable parse error occurs and no annotation token can be 745/// formed, this function returns true. 746/// 747bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK, 748 const CXXScopeSpec *SS, 749 UnqualifiedId &TemplateName, 750 SourceLocation TemplateKWLoc, 751 bool AllowTypeAnnotation) { 752 assert(getLang().CPlusPlus && "Can only annotate template-ids in C++"); 753 assert(Template && Tok.is(tok::less) && 754 "Parser isn't at the beginning of a template-id"); 755 756 // Consume the template-name. 757 SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin(); 758 759 // Parse the enclosed template argument list. 760 SourceLocation LAngleLoc, RAngleLoc; 761 TemplateArgList TemplateArgs; 762 bool Invalid = ParseTemplateIdAfterTemplateName(Template, 763 TemplateNameLoc, 764 SS, false, LAngleLoc, 765 TemplateArgs, 766 RAngleLoc); 767 768 if (Invalid) { 769 // If we failed to parse the template ID but skipped ahead to a >, we're not 770 // going to be able to form a token annotation. Eat the '>' if present. 771 if (Tok.is(tok::greater)) 772 ConsumeToken(); 773 return true; 774 } 775 776 ASTTemplateArgsPtr TemplateArgsPtr(Actions, TemplateArgs.data(), 777 TemplateArgs.size()); 778 779 // Build the annotation token. 780 if (TNK == TNK_Type_template && AllowTypeAnnotation) { 781 TypeResult Type 782 = Actions.ActOnTemplateIdType(Template, TemplateNameLoc, 783 LAngleLoc, TemplateArgsPtr, 784 RAngleLoc); 785 if (Type.isInvalid()) { 786 // If we failed to parse the template ID but skipped ahead to a >, we're not 787 // going to be able to form a token annotation. Eat the '>' if present. 788 if (Tok.is(tok::greater)) 789 ConsumeToken(); 790 return true; 791 } 792 793 Tok.setKind(tok::annot_typename); 794 setTypeAnnotation(Tok, Type.get()); 795 if (SS && SS->isNotEmpty()) 796 Tok.setLocation(SS->getBeginLoc()); 797 else if (TemplateKWLoc.isValid()) 798 Tok.setLocation(TemplateKWLoc); 799 else 800 Tok.setLocation(TemplateNameLoc); 801 } else { 802 // Build a template-id annotation token that can be processed 803 // later. 804 Tok.setKind(tok::annot_template_id); 805 TemplateIdAnnotation *TemplateId 806 = TemplateIdAnnotation::Allocate(TemplateArgs.size()); 807 TemplateId->TemplateNameLoc = TemplateNameLoc; 808 if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) { 809 TemplateId->Name = TemplateName.Identifier; 810 TemplateId->Operator = OO_None; 811 } else { 812 TemplateId->Name = 0; 813 TemplateId->Operator = TemplateName.OperatorFunctionId.Operator; 814 } 815 TemplateId->Template = Template; 816 TemplateId->Kind = TNK; 817 TemplateId->LAngleLoc = LAngleLoc; 818 TemplateId->RAngleLoc = RAngleLoc; 819 ParsedTemplateArgument *Args = TemplateId->getTemplateArgs(); 820 for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) 821 Args[Arg] = TemplateArgs[Arg]; 822 Tok.setAnnotationValue(TemplateId); 823 if (TemplateKWLoc.isValid()) 824 Tok.setLocation(TemplateKWLoc); 825 else 826 Tok.setLocation(TemplateNameLoc); 827 828 TemplateArgsPtr.release(); 829 } 830 831 // Common fields for the annotation token 832 Tok.setAnnotationEndLoc(RAngleLoc); 833 834 // In case the tokens were cached, have Preprocessor replace them with the 835 // annotation token. 836 PP.AnnotateCachedTokens(Tok); 837 return false; 838} 839 840/// \brief Replaces a template-id annotation token with a type 841/// annotation token. 842/// 843/// If there was a failure when forming the type from the template-id, 844/// a type annotation token will still be created, but will have a 845/// NULL type pointer to signify an error. 846void Parser::AnnotateTemplateIdTokenAsType(const CXXScopeSpec *SS) { 847 assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens"); 848 849 TemplateIdAnnotation *TemplateId 850 = static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue()); 851 assert((TemplateId->Kind == TNK_Type_template || 852 TemplateId->Kind == TNK_Dependent_template_name) && 853 "Only works for type and dependent templates"); 854 855 ASTTemplateArgsPtr TemplateArgsPtr(Actions, 856 TemplateId->getTemplateArgs(), 857 TemplateId->NumArgs); 858 859 TypeResult Type 860 = Actions.ActOnTemplateIdType(TemplateId->Template, 861 TemplateId->TemplateNameLoc, 862 TemplateId->LAngleLoc, 863 TemplateArgsPtr, 864 TemplateId->RAngleLoc); 865 // Create the new "type" annotation token. 866 Tok.setKind(tok::annot_typename); 867 setTypeAnnotation(Tok, Type.isInvalid() ? ParsedType() : Type.get()); 868 if (SS && SS->isNotEmpty()) // it was a C++ qualified type name. 869 Tok.setLocation(SS->getBeginLoc()); 870 // End location stays the same 871 872 // Replace the template-id annotation token, and possible the scope-specifier 873 // that precedes it, with the typename annotation token. 874 PP.AnnotateCachedTokens(Tok); 875 TemplateId->Destroy(); 876} 877 878/// \brief Determine whether the given token can end a template argument. 879static bool isEndOfTemplateArgument(Token Tok) { 880 return Tok.is(tok::comma) || Tok.is(tok::greater) || 881 Tok.is(tok::greatergreater); 882} 883 884/// \brief Parse a C++ template template argument. 885ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() { 886 if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) && 887 !Tok.is(tok::annot_cxxscope)) 888 return ParsedTemplateArgument(); 889 890 // C++0x [temp.arg.template]p1: 891 // A template-argument for a template template-parameter shall be the name 892 // of a class template or a template alias, expressed as id-expression. 893 // 894 // We parse an id-expression that refers to a class template or template 895 // alias. The grammar we parse is: 896 // 897 // nested-name-specifier[opt] template[opt] identifier 898 // 899 // followed by a token that terminates a template argument, such as ',', 900 // '>', or (in some cases) '>>'. 901 CXXScopeSpec SS; // nested-name-specifier, if present 902 ParseOptionalCXXScopeSpecifier(SS, ParsedType(), 903 /*EnteringContext=*/false); 904 905 if (SS.isSet() && Tok.is(tok::kw_template)) { 906 // Parse the optional 'template' keyword following the 907 // nested-name-specifier. 908 SourceLocation TemplateLoc = ConsumeToken(); 909 910 if (Tok.is(tok::identifier)) { 911 // We appear to have a dependent template name. 912 UnqualifiedId Name; 913 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 914 ConsumeToken(); // the identifier 915 916 // If the next token signals the end of a template argument, 917 // then we have a dependent template name that could be a template 918 // template argument. 919 TemplateTy Template; 920 if (isEndOfTemplateArgument(Tok) && 921 Actions.ActOnDependentTemplateName(getCurScope(), TemplateLoc, 922 SS, Name, 923 /*ObjectType=*/ ParsedType(), 924 /*EnteringContext=*/false, 925 Template)) 926 return ParsedTemplateArgument(SS, Template, Name.StartLocation); 927 } 928 } else if (Tok.is(tok::identifier)) { 929 // We may have a (non-dependent) template name. 930 TemplateTy Template; 931 UnqualifiedId Name; 932 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 933 ConsumeToken(); // the identifier 934 935 if (isEndOfTemplateArgument(Tok)) { 936 bool MemberOfUnknownSpecialization; 937 TemplateNameKind TNK = Actions.isTemplateName(getCurScope(), SS, 938 /*hasTemplateKeyword=*/false, 939 Name, 940 /*ObjectType=*/ ParsedType(), 941 /*EnteringContext=*/false, 942 Template, 943 MemberOfUnknownSpecialization); 944 if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) { 945 // We have an id-expression that refers to a class template or 946 // (C++0x) template alias. 947 return ParsedTemplateArgument(SS, Template, Name.StartLocation); 948 } 949 } 950 } 951 952 // We don't have a template template argument. 953 return ParsedTemplateArgument(); 954} 955 956/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). 957/// 958/// template-argument: [C++ 14.2] 959/// constant-expression 960/// type-id 961/// id-expression 962ParsedTemplateArgument Parser::ParseTemplateArgument() { 963 // C++ [temp.arg]p2: 964 // In a template-argument, an ambiguity between a type-id and an 965 // expression is resolved to a type-id, regardless of the form of 966 // the corresponding template-parameter. 967 // 968 // Therefore, we initially try to parse a type-id. 969 if (isCXXTypeId(TypeIdAsTemplateArgument)) { 970 SourceLocation Loc = Tok.getLocation(); 971 TypeResult TypeArg = ParseTypeName(); 972 if (TypeArg.isInvalid()) 973 return ParsedTemplateArgument(); 974 975 return ParsedTemplateArgument(ParsedTemplateArgument::Type, 976 TypeArg.get().getAsOpaquePtr(), 977 Loc); 978 } 979 980 // Try to parse a template template argument. 981 { 982 TentativeParsingAction TPA(*this); 983 984 ParsedTemplateArgument TemplateTemplateArgument 985 = ParseTemplateTemplateArgument(); 986 if (!TemplateTemplateArgument.isInvalid()) { 987 TPA.Commit(); 988 return TemplateTemplateArgument; 989 } 990 991 // Revert this tentative parse to parse a non-type template argument. 992 TPA.Revert(); 993 } 994 995 // Parse a non-type template argument. 996 SourceLocation Loc = Tok.getLocation(); 997 ExprResult ExprArg = ParseConstantExpression(); 998 if (ExprArg.isInvalid() || !ExprArg.get()) 999 return ParsedTemplateArgument(); 1000 1001 return ParsedTemplateArgument(ParsedTemplateArgument::NonType, 1002 ExprArg.release(), Loc); 1003} 1004 1005/// \brief Determine whether the current tokens can only be parsed as a 1006/// template argument list (starting with the '<') and never as a '<' 1007/// expression. 1008bool Parser::IsTemplateArgumentList(unsigned Skip) { 1009 struct AlwaysRevertAction : TentativeParsingAction { 1010 AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { } 1011 ~AlwaysRevertAction() { Revert(); } 1012 } Tentative(*this); 1013 1014 while (Skip) { 1015 ConsumeToken(); 1016 --Skip; 1017 } 1018 1019 // '<' 1020 if (!Tok.is(tok::less)) 1021 return false; 1022 ConsumeToken(); 1023 1024 // An empty template argument list. 1025 if (Tok.is(tok::greater)) 1026 return true; 1027 1028 // See whether we have declaration specifiers, which indicate a type. 1029 while (isCXXDeclarationSpecifier() == TPResult::True()) 1030 ConsumeToken(); 1031 1032 // If we have a '>' or a ',' then this is a template argument list. 1033 return Tok.is(tok::greater) || Tok.is(tok::comma); 1034} 1035 1036/// ParseTemplateArgumentList - Parse a C++ template-argument-list 1037/// (C++ [temp.names]). Returns true if there was an error. 1038/// 1039/// template-argument-list: [C++ 14.2] 1040/// template-argument 1041/// template-argument-list ',' template-argument 1042bool 1043Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) { 1044 while (true) { 1045 ParsedTemplateArgument Arg = ParseTemplateArgument(); 1046 if (Tok.is(tok::ellipsis)) { 1047 SourceLocation EllipsisLoc = ConsumeToken(); 1048 Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc); 1049 } 1050 1051 if (Arg.isInvalid()) { 1052 SkipUntil(tok::comma, tok::greater, true, true); 1053 return true; 1054 } 1055 1056 // Save this template argument. 1057 TemplateArgs.push_back(Arg); 1058 1059 // If the next token is a comma, consume it and keep reading 1060 // arguments. 1061 if (Tok.isNot(tok::comma)) break; 1062 1063 // Consume the comma. 1064 ConsumeToken(); 1065 } 1066 1067 return false; 1068} 1069 1070/// \brief Parse a C++ explicit template instantiation 1071/// (C++ [temp.explicit]). 1072/// 1073/// explicit-instantiation: 1074/// 'extern' [opt] 'template' declaration 1075/// 1076/// Note that the 'extern' is a GNU extension and C++0x feature. 1077Decl *Parser::ParseExplicitInstantiation(SourceLocation ExternLoc, 1078 SourceLocation TemplateLoc, 1079 SourceLocation &DeclEnd) { 1080 // This isn't really required here. 1081 ParsingDeclRAIIObject ParsingTemplateParams(*this); 1082 1083 return ParseSingleDeclarationAfterTemplate(Declarator::FileContext, 1084 ParsedTemplateInfo(ExternLoc, 1085 TemplateLoc), 1086 ParsingTemplateParams, 1087 DeclEnd, AS_none); 1088} 1089 1090SourceRange Parser::ParsedTemplateInfo::getSourceRange() const { 1091 if (TemplateParams) 1092 return getTemplateParamsRange(TemplateParams->data(), 1093 TemplateParams->size()); 1094 1095 SourceRange R(TemplateLoc); 1096 if (ExternLoc.isValid()) 1097 R.setBegin(ExternLoc); 1098 return R; 1099} 1100