ParseTemplate.cpp revision 208954
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/Parse/DeclSpec.h" 17#include "clang/Parse/Scope.h" 18#include "clang/Parse/Template.h" 19#include "RAIIObjectsForParser.h" 20using namespace clang; 21 22/// \brief Parse a template declaration, explicit instantiation, or 23/// explicit specialization. 24Parser::DeclPtrTy 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 73Parser::DeclPtrTy 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 // Parse multiple levels of template headers within this template 84 // parameter scope, e.g., 85 // 86 // template<typename T> 87 // template<typename U> 88 // class A<T>::B { ... }; 89 // 90 // We parse multiple levels non-recursively so that we can build a 91 // single data structure containing all of the template parameter 92 // lists to easily differentiate between the case above and: 93 // 94 // template<typename T> 95 // class A { 96 // template<typename U> class B; 97 // }; 98 // 99 // In the first case, the action for declaring A<T>::B receives 100 // both template parameter lists. In the second case, the action for 101 // defining A<T>::B receives just the inner template parameter list 102 // (and retrieves the outer template parameter list from its 103 // context). 104 bool isSpecialization = true; 105 bool LastParamListWasEmpty = false; 106 TemplateParameterLists ParamLists; 107 TemplateParameterDepthCounter Depth(TemplateParameterDepth); 108 do { 109 // Consume the 'export', if any. 110 SourceLocation ExportLoc; 111 if (Tok.is(tok::kw_export)) { 112 ExportLoc = ConsumeToken(); 113 } 114 115 // Consume the 'template', which should be here. 116 SourceLocation TemplateLoc; 117 if (Tok.is(tok::kw_template)) { 118 TemplateLoc = ConsumeToken(); 119 } else { 120 Diag(Tok.getLocation(), diag::err_expected_template); 121 return DeclPtrTy(); 122 } 123 124 // Parse the '<' template-parameter-list '>' 125 SourceLocation LAngleLoc, RAngleLoc; 126 TemplateParameterList TemplateParams; 127 if (ParseTemplateParameters(Depth, TemplateParams, LAngleLoc, 128 RAngleLoc)) { 129 // Skip until the semi-colon or a }. 130 SkipUntil(tok::r_brace, true, true); 131 if (Tok.is(tok::semi)) 132 ConsumeToken(); 133 return DeclPtrTy(); 134 } 135 136 ParamLists.push_back( 137 Actions.ActOnTemplateParameterList(Depth, ExportLoc, 138 TemplateLoc, LAngleLoc, 139 TemplateParams.data(), 140 TemplateParams.size(), RAngleLoc)); 141 142 if (!TemplateParams.empty()) { 143 isSpecialization = false; 144 ++Depth; 145 } else { 146 LastParamListWasEmpty = true; 147 } 148 } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template)); 149 150 // Parse the actual template declaration. 151 return ParseSingleDeclarationAfterTemplate(Context, 152 ParsedTemplateInfo(&ParamLists, 153 isSpecialization, 154 LastParamListWasEmpty), 155 DeclEnd, AS); 156} 157 158/// \brief Parse a single declaration that declares a template, 159/// template specialization, or explicit instantiation of a template. 160/// 161/// \param TemplateParams if non-NULL, the template parameter lists 162/// that preceded this declaration. In this case, the declaration is a 163/// template declaration, out-of-line definition of a template, or an 164/// explicit template specialization. When NULL, the declaration is an 165/// explicit template instantiation. 166/// 167/// \param TemplateLoc when TemplateParams is NULL, the location of 168/// the 'template' keyword that indicates that we have an explicit 169/// template instantiation. 170/// 171/// \param DeclEnd will receive the source location of the last token 172/// within this declaration. 173/// 174/// \param AS the access specifier associated with this 175/// declaration. Will be AS_none for namespace-scope declarations. 176/// 177/// \returns the new declaration. 178Parser::DeclPtrTy 179Parser::ParseSingleDeclarationAfterTemplate( 180 unsigned Context, 181 const ParsedTemplateInfo &TemplateInfo, 182 SourceLocation &DeclEnd, 183 AccessSpecifier AS) { 184 assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate && 185 "Template information required"); 186 187 if (Context == Declarator::MemberContext) { 188 // We are parsing a member template. 189 ParseCXXClassMemberDeclaration(AS, TemplateInfo); 190 return DeclPtrTy::make((void*)0); 191 } 192 193 // Parse the declaration specifiers. 194 ParsingDeclSpec DS(*this); 195 196 if (getLang().CPlusPlus0x && isCXX0XAttributeSpecifier()) 197 DS.AddAttributes(ParseCXX0XAttributes().AttrList); 198 199 ParseDeclarationSpecifiers(DS, TemplateInfo, AS, 200 getDeclSpecContextFromDeclaratorContext(Context)); 201 202 if (Tok.is(tok::semi)) { 203 DeclEnd = ConsumeToken(); 204 DeclPtrTy Decl = Actions.ParsedFreeStandingDeclSpec(CurScope, AS, DS); 205 DS.complete(Decl); 206 return Decl; 207 } 208 209 // Parse the declarator. 210 ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context); 211 ParseDeclarator(DeclaratorInfo); 212 // Error parsing the declarator? 213 if (!DeclaratorInfo.hasName()) { 214 // If so, skip until the semi-colon or a }. 215 SkipUntil(tok::r_brace, true, true); 216 if (Tok.is(tok::semi)) 217 ConsumeToken(); 218 return DeclPtrTy(); 219 } 220 221 // If we have a declaration or declarator list, handle it. 222 if (isDeclarationAfterDeclarator()) { 223 // Parse this declaration. 224 DeclPtrTy ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo, 225 TemplateInfo); 226 227 if (Tok.is(tok::comma)) { 228 Diag(Tok, diag::err_multiple_template_declarators) 229 << (int)TemplateInfo.Kind; 230 SkipUntil(tok::semi, true, false); 231 return ThisDecl; 232 } 233 234 // Eat the semi colon after the declaration. 235 ExpectAndConsume(tok::semi, diag::err_expected_semi_declaration); 236 DS.complete(ThisDecl); 237 return ThisDecl; 238 } 239 240 if (DeclaratorInfo.isFunctionDeclarator() && 241 isStartOfFunctionDefinition()) { 242 if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) { 243 Diag(Tok, diag::err_function_declared_typedef); 244 245 if (Tok.is(tok::l_brace)) { 246 // This recovery skips the entire function body. It would be nice 247 // to simply call ParseFunctionDefinition() below, however Sema 248 // assumes the declarator represents a function, not a typedef. 249 ConsumeBrace(); 250 SkipUntil(tok::r_brace, true); 251 } else { 252 SkipUntil(tok::semi); 253 } 254 return DeclPtrTy(); 255 } 256 return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo); 257 } 258 259 if (DeclaratorInfo.isFunctionDeclarator()) 260 Diag(Tok, diag::err_expected_fn_body); 261 else 262 Diag(Tok, diag::err_invalid_token_after_toplevel_declarator); 263 SkipUntil(tok::semi); 264 return DeclPtrTy(); 265} 266 267/// ParseTemplateParameters - Parses a template-parameter-list enclosed in 268/// angle brackets. Depth is the depth of this template-parameter-list, which 269/// is the number of template headers directly enclosing this template header. 270/// TemplateParams is the current list of template parameters we're building. 271/// The template parameter we parse will be added to this list. LAngleLoc and 272/// RAngleLoc will receive the positions of the '<' and '>', respectively, 273/// that enclose this template parameter list. 274/// 275/// \returns true if an error occurred, false otherwise. 276bool Parser::ParseTemplateParameters(unsigned Depth, 277 TemplateParameterList &TemplateParams, 278 SourceLocation &LAngleLoc, 279 SourceLocation &RAngleLoc) { 280 // Get the template parameter list. 281 if (!Tok.is(tok::less)) { 282 Diag(Tok.getLocation(), diag::err_expected_less_after) << "template"; 283 return true; 284 } 285 LAngleLoc = ConsumeToken(); 286 287 // Try to parse the template parameter list. 288 if (Tok.is(tok::greater)) 289 RAngleLoc = ConsumeToken(); 290 else if (ParseTemplateParameterList(Depth, TemplateParams)) { 291 if (!Tok.is(tok::greater)) { 292 Diag(Tok.getLocation(), diag::err_expected_greater); 293 return true; 294 } 295 RAngleLoc = ConsumeToken(); 296 } 297 return false; 298} 299 300/// ParseTemplateParameterList - Parse a template parameter list. If 301/// the parsing fails badly (i.e., closing bracket was left out), this 302/// will try to put the token stream in a reasonable position (closing 303/// a statement, etc.) and return false. 304/// 305/// template-parameter-list: [C++ temp] 306/// template-parameter 307/// template-parameter-list ',' template-parameter 308bool 309Parser::ParseTemplateParameterList(unsigned Depth, 310 TemplateParameterList &TemplateParams) { 311 while (1) { 312 if (DeclPtrTy TmpParam 313 = ParseTemplateParameter(Depth, TemplateParams.size())) { 314 TemplateParams.push_back(TmpParam); 315 } else { 316 // If we failed to parse a template parameter, skip until we find 317 // a comma or closing brace. 318 SkipUntil(tok::comma, tok::greater, true, true); 319 } 320 321 // Did we find a comma or the end of the template parmeter list? 322 if (Tok.is(tok::comma)) { 323 ConsumeToken(); 324 } else if (Tok.is(tok::greater)) { 325 // Don't consume this... that's done by template parser. 326 break; 327 } else { 328 // Somebody probably forgot to close the template. Skip ahead and 329 // try to get out of the expression. This error is currently 330 // subsumed by whatever goes on in ParseTemplateParameter. 331 // TODO: This could match >>, and it would be nice to avoid those 332 // silly errors with template <vec<T>>. 333 // Diag(Tok.getLocation(), diag::err_expected_comma_greater); 334 SkipUntil(tok::greater, true, true); 335 return false; 336 } 337 } 338 return true; 339} 340 341/// \brief Determine whether the parser is at the start of a template 342/// type parameter. 343bool Parser::isStartOfTemplateTypeParameter() { 344 if (Tok.is(tok::kw_class)) 345 return true; 346 347 if (Tok.isNot(tok::kw_typename)) 348 return false; 349 350 // C++ [temp.param]p2: 351 // There is no semantic difference between class and typename in a 352 // template-parameter. typename followed by an unqualified-id 353 // names a template type parameter. typename followed by a 354 // qualified-id denotes the type in a non-type 355 // parameter-declaration. 356 Token Next = NextToken(); 357 358 // If we have an identifier, skip over it. 359 if (Next.getKind() == tok::identifier) 360 Next = GetLookAheadToken(2); 361 362 switch (Next.getKind()) { 363 case tok::equal: 364 case tok::comma: 365 case tok::greater: 366 case tok::greatergreater: 367 case tok::ellipsis: 368 return true; 369 370 default: 371 return false; 372 } 373} 374 375/// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]). 376/// 377/// template-parameter: [C++ temp.param] 378/// type-parameter 379/// parameter-declaration 380/// 381/// type-parameter: (see below) 382/// 'class' ...[opt][C++0x] identifier[opt] 383/// 'class' identifier[opt] '=' type-id 384/// 'typename' ...[opt][C++0x] identifier[opt] 385/// 'typename' identifier[opt] '=' type-id 386/// 'template' ...[opt][C++0x] '<' template-parameter-list '>' 'class' identifier[opt] 387/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression 388Parser::DeclPtrTy 389Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { 390 if (isStartOfTemplateTypeParameter()) 391 return ParseTypeParameter(Depth, Position); 392 393 if (Tok.is(tok::kw_template)) 394 return ParseTemplateTemplateParameter(Depth, Position); 395 396 // If it's none of the above, then it must be a parameter declaration. 397 // NOTE: This will pick up errors in the closure of the template parameter 398 // list (e.g., template < ; Check here to implement >> style closures. 399 return ParseNonTypeTemplateParameter(Depth, Position); 400} 401 402/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]). 403/// Other kinds of template parameters are parsed in 404/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter. 405/// 406/// type-parameter: [C++ temp.param] 407/// 'class' ...[opt][C++0x] identifier[opt] 408/// 'class' identifier[opt] '=' type-id 409/// 'typename' ...[opt][C++0x] identifier[opt] 410/// 'typename' identifier[opt] '=' type-id 411Parser::DeclPtrTy Parser::ParseTypeParameter(unsigned Depth, unsigned Position){ 412 assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) && 413 "A type-parameter starts with 'class' or 'typename'"); 414 415 // Consume the 'class' or 'typename' keyword. 416 bool TypenameKeyword = Tok.is(tok::kw_typename); 417 SourceLocation KeyLoc = ConsumeToken(); 418 419 // Grab the ellipsis (if given). 420 bool Ellipsis = false; 421 SourceLocation EllipsisLoc; 422 if (Tok.is(tok::ellipsis)) { 423 Ellipsis = true; 424 EllipsisLoc = ConsumeToken(); 425 426 if (!getLang().CPlusPlus0x) 427 Diag(EllipsisLoc, diag::err_variadic_templates); 428 } 429 430 // Grab the template parameter name (if given) 431 SourceLocation NameLoc; 432 IdentifierInfo* ParamName = 0; 433 if (Tok.is(tok::identifier)) { 434 ParamName = Tok.getIdentifierInfo(); 435 NameLoc = ConsumeToken(); 436 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || 437 Tok.is(tok::greater)) { 438 // Unnamed template parameter. Don't have to do anything here, just 439 // don't consume this token. 440 } else { 441 Diag(Tok.getLocation(), diag::err_expected_ident); 442 return DeclPtrTy(); 443 } 444 445 DeclPtrTy TypeParam = Actions.ActOnTypeParameter(CurScope, TypenameKeyword, 446 Ellipsis, EllipsisLoc, 447 KeyLoc, ParamName, NameLoc, 448 Depth, Position); 449 450 // Grab a default type id (if given). 451 if (Tok.is(tok::equal)) { 452 SourceLocation EqualLoc = ConsumeToken(); 453 SourceLocation DefaultLoc = Tok.getLocation(); 454 TypeResult DefaultType = ParseTypeName(); 455 if (!DefaultType.isInvalid()) 456 Actions.ActOnTypeParameterDefault(TypeParam, EqualLoc, DefaultLoc, 457 DefaultType.get()); 458 } 459 460 return TypeParam; 461} 462 463/// ParseTemplateTemplateParameter - Handle the parsing of template 464/// template parameters. 465/// 466/// type-parameter: [C++ temp.param] 467/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] 468/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression 469Parser::DeclPtrTy 470Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { 471 assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); 472 473 // Handle the template <...> part. 474 SourceLocation TemplateLoc = ConsumeToken(); 475 TemplateParameterList TemplateParams; 476 SourceLocation LAngleLoc, RAngleLoc; 477 { 478 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 479 if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, 480 RAngleLoc)) { 481 return DeclPtrTy(); 482 } 483 } 484 485 // Generate a meaningful error if the user forgot to put class before the 486 // identifier, comma, or greater. 487 if (!Tok.is(tok::kw_class)) { 488 Diag(Tok.getLocation(), diag::err_expected_class_before) 489 << PP.getSpelling(Tok); 490 return DeclPtrTy(); 491 } 492 SourceLocation ClassLoc = ConsumeToken(); 493 494 // Get the identifier, if given. 495 SourceLocation NameLoc; 496 IdentifierInfo* ParamName = 0; 497 if (Tok.is(tok::identifier)) { 498 ParamName = Tok.getIdentifierInfo(); 499 NameLoc = ConsumeToken(); 500 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater)) { 501 // Unnamed template parameter. Don't have to do anything here, just 502 // don't consume this token. 503 } else { 504 Diag(Tok.getLocation(), diag::err_expected_ident); 505 return DeclPtrTy(); 506 } 507 508 TemplateParamsTy *ParamList = 509 Actions.ActOnTemplateParameterList(Depth, SourceLocation(), 510 TemplateLoc, LAngleLoc, 511 &TemplateParams[0], 512 TemplateParams.size(), 513 RAngleLoc); 514 515 Parser::DeclPtrTy Param 516 = Actions.ActOnTemplateTemplateParameter(CurScope, TemplateLoc, 517 ParamList, ParamName, 518 NameLoc, Depth, Position); 519 520 // Get the a default value, if given. 521 if (Tok.is(tok::equal)) { 522 SourceLocation EqualLoc = ConsumeToken(); 523 ParsedTemplateArgument Default = ParseTemplateTemplateArgument(); 524 if (Default.isInvalid()) { 525 Diag(Tok.getLocation(), 526 diag::err_default_template_template_parameter_not_template); 527 static const tok::TokenKind EndToks[] = { 528 tok::comma, tok::greater, tok::greatergreater 529 }; 530 SkipUntil(EndToks, 3, true, true); 531 return Param; 532 } else if (Param) 533 Actions.ActOnTemplateTemplateParameterDefault(Param, EqualLoc, Default); 534 } 535 536 return Param; 537} 538 539/// ParseNonTypeTemplateParameter - Handle the parsing of non-type 540/// template parameters (e.g., in "template<int Size> class array;"). 541/// 542/// template-parameter: 543/// ... 544/// parameter-declaration 545/// 546/// NOTE: It would be ideal to simply call out to ParseParameterDeclaration(), 547/// but that didn't work out to well. Instead, this tries to recrate the basic 548/// parsing of parameter declarations, but tries to constrain it for template 549/// parameters. 550/// FIXME: We need to make a ParseParameterDeclaration that works for 551/// non-type template parameters and normal function parameters. 552Parser::DeclPtrTy 553Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { 554 SourceLocation StartLoc = Tok.getLocation(); 555 556 // Parse the declaration-specifiers (i.e., the type). 557 // FIXME: The type should probably be restricted in some way... Not all 558 // declarators (parts of declarators?) are accepted for parameters. 559 DeclSpec DS; 560 ParseDeclarationSpecifiers(DS); 561 562 // Parse this as a typename. 563 Declarator ParamDecl(DS, Declarator::TemplateParamContext); 564 ParseDeclarator(ParamDecl); 565 if (DS.getTypeSpecType() == DeclSpec::TST_unspecified && !DS.getTypeRep()) { 566 // This probably shouldn't happen - and it's more of a Sema thing, but 567 // basically we didn't parse the type name because we couldn't associate 568 // it with an AST node. we should just skip to the comma or greater. 569 // TODO: This is currently a placeholder for some kind of Sema Error. 570 Diag(Tok.getLocation(), diag::err_parse_error); 571 SkipUntil(tok::comma, tok::greater, true, true); 572 return DeclPtrTy(); 573 } 574 575 // Create the parameter. 576 DeclPtrTy Param = Actions.ActOnNonTypeTemplateParameter(CurScope, ParamDecl, 577 Depth, Position); 578 579 // If there is a default value, parse it. 580 if (Tok.is(tok::equal)) { 581 SourceLocation EqualLoc = ConsumeToken(); 582 583 // C++ [temp.param]p15: 584 // When parsing a default template-argument for a non-type 585 // template-parameter, the first non-nested > is taken as the 586 // end of the template-parameter-list rather than a greater-than 587 // operator. 588 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 589 590 OwningExprResult DefaultArg = ParseAssignmentExpression(); 591 if (DefaultArg.isInvalid()) 592 SkipUntil(tok::comma, tok::greater, true, true); 593 else if (Param) 594 Actions.ActOnNonTypeTemplateParameterDefault(Param, EqualLoc, 595 move(DefaultArg)); 596 } 597 598 return Param; 599} 600 601/// \brief Parses a template-id that after the template name has 602/// already been parsed. 603/// 604/// This routine takes care of parsing the enclosed template argument 605/// list ('<' template-parameter-list [opt] '>') and placing the 606/// results into a form that can be transferred to semantic analysis. 607/// 608/// \param Template the template declaration produced by isTemplateName 609/// 610/// \param TemplateNameLoc the source location of the template name 611/// 612/// \param SS if non-NULL, the nested-name-specifier preceding the 613/// template name. 614/// 615/// \param ConsumeLastToken if true, then we will consume the last 616/// token that forms the template-id. Otherwise, we will leave the 617/// last token in the stream (e.g., so that it can be replaced with an 618/// annotation token). 619bool 620Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template, 621 SourceLocation TemplateNameLoc, 622 const CXXScopeSpec *SS, 623 bool ConsumeLastToken, 624 SourceLocation &LAngleLoc, 625 TemplateArgList &TemplateArgs, 626 SourceLocation &RAngleLoc) { 627 assert(Tok.is(tok::less) && "Must have already parsed the template-name"); 628 629 // Consume the '<'. 630 LAngleLoc = ConsumeToken(); 631 632 // Parse the optional template-argument-list. 633 bool Invalid = false; 634 { 635 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 636 if (Tok.isNot(tok::greater)) 637 Invalid = ParseTemplateArgumentList(TemplateArgs); 638 639 if (Invalid) { 640 // Try to find the closing '>'. 641 SkipUntil(tok::greater, true, !ConsumeLastToken); 642 643 return true; 644 } 645 } 646 647 if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) { 648 Diag(Tok.getLocation(), diag::err_expected_greater); 649 return true; 650 } 651 652 // Determine the location of the '>' or '>>'. Only consume this 653 // token if the caller asked us to. 654 RAngleLoc = Tok.getLocation(); 655 656 if (Tok.is(tok::greatergreater)) { 657 if (!getLang().CPlusPlus0x) { 658 const char *ReplaceStr = "> >"; 659 if (NextToken().is(tok::greater) || NextToken().is(tok::greatergreater)) 660 ReplaceStr = "> > "; 661 662 Diag(Tok.getLocation(), diag::err_two_right_angle_brackets_need_space) 663 << FixItHint::CreateReplacement( 664 SourceRange(Tok.getLocation()), ReplaceStr); 665 } 666 667 Tok.setKind(tok::greater); 668 if (!ConsumeLastToken) { 669 // Since we're not supposed to consume the '>>' token, we need 670 // to insert a second '>' token after the first. 671 PP.EnterToken(Tok); 672 } 673 } else if (ConsumeLastToken) 674 ConsumeToken(); 675 676 return false; 677} 678 679/// \brief Replace the tokens that form a simple-template-id with an 680/// annotation token containing the complete template-id. 681/// 682/// The first token in the stream must be the name of a template that 683/// is followed by a '<'. This routine will parse the complete 684/// simple-template-id and replace the tokens with a single annotation 685/// token with one of two different kinds: if the template-id names a 686/// type (and \p AllowTypeAnnotation is true), the annotation token is 687/// a type annotation that includes the optional nested-name-specifier 688/// (\p SS). Otherwise, the annotation token is a template-id 689/// annotation that does not include the optional 690/// nested-name-specifier. 691/// 692/// \param Template the declaration of the template named by the first 693/// token (an identifier), as returned from \c Action::isTemplateName(). 694/// 695/// \param TemplateNameKind the kind of template that \p Template 696/// refers to, as returned from \c Action::isTemplateName(). 697/// 698/// \param SS if non-NULL, the nested-name-specifier that precedes 699/// this template name. 700/// 701/// \param TemplateKWLoc if valid, specifies that this template-id 702/// annotation was preceded by the 'template' keyword and gives the 703/// location of that keyword. If invalid (the default), then this 704/// template-id was not preceded by a 'template' keyword. 705/// 706/// \param AllowTypeAnnotation if true (the default), then a 707/// simple-template-id that refers to a class template, template 708/// template parameter, or other template that produces a type will be 709/// replaced with a type annotation token. Otherwise, the 710/// simple-template-id is always replaced with a template-id 711/// annotation token. 712/// 713/// If an unrecoverable parse error occurs and no annotation token can be 714/// formed, this function returns true. 715/// 716bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK, 717 const CXXScopeSpec *SS, 718 UnqualifiedId &TemplateName, 719 SourceLocation TemplateKWLoc, 720 bool AllowTypeAnnotation) { 721 assert(getLang().CPlusPlus && "Can only annotate template-ids in C++"); 722 assert(Template && Tok.is(tok::less) && 723 "Parser isn't at the beginning of a template-id"); 724 725 // Consume the template-name. 726 SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin(); 727 728 // Parse the enclosed template argument list. 729 SourceLocation LAngleLoc, RAngleLoc; 730 TemplateArgList TemplateArgs; 731 bool Invalid = ParseTemplateIdAfterTemplateName(Template, 732 TemplateNameLoc, 733 SS, false, LAngleLoc, 734 TemplateArgs, 735 RAngleLoc); 736 737 if (Invalid) { 738 // If we failed to parse the template ID but skipped ahead to a >, we're not 739 // going to be able to form a token annotation. Eat the '>' if present. 740 if (Tok.is(tok::greater)) 741 ConsumeToken(); 742 return true; 743 } 744 745 ASTTemplateArgsPtr TemplateArgsPtr(Actions, TemplateArgs.data(), 746 TemplateArgs.size()); 747 748 // Build the annotation token. 749 if (TNK == TNK_Type_template && AllowTypeAnnotation) { 750 Action::TypeResult Type 751 = Actions.ActOnTemplateIdType(Template, TemplateNameLoc, 752 LAngleLoc, TemplateArgsPtr, 753 RAngleLoc); 754 if (Type.isInvalid()) { 755 // If we failed to parse the template ID but skipped ahead to a >, we're not 756 // going to be able to form a token annotation. Eat the '>' if present. 757 if (Tok.is(tok::greater)) 758 ConsumeToken(); 759 return true; 760 } 761 762 Tok.setKind(tok::annot_typename); 763 Tok.setAnnotationValue(Type.get()); 764 if (SS && SS->isNotEmpty()) 765 Tok.setLocation(SS->getBeginLoc()); 766 else if (TemplateKWLoc.isValid()) 767 Tok.setLocation(TemplateKWLoc); 768 else 769 Tok.setLocation(TemplateNameLoc); 770 } else { 771 // Build a template-id annotation token that can be processed 772 // later. 773 Tok.setKind(tok::annot_template_id); 774 TemplateIdAnnotation *TemplateId 775 = TemplateIdAnnotation::Allocate(TemplateArgs.size()); 776 TemplateId->TemplateNameLoc = TemplateNameLoc; 777 if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) { 778 TemplateId->Name = TemplateName.Identifier; 779 TemplateId->Operator = OO_None; 780 } else { 781 TemplateId->Name = 0; 782 TemplateId->Operator = TemplateName.OperatorFunctionId.Operator; 783 } 784 TemplateId->Template = Template.getAs<void*>(); 785 TemplateId->Kind = TNK; 786 TemplateId->LAngleLoc = LAngleLoc; 787 TemplateId->RAngleLoc = RAngleLoc; 788 ParsedTemplateArgument *Args = TemplateId->getTemplateArgs(); 789 for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) 790 Args[Arg] = TemplateArgs[Arg]; 791 Tok.setAnnotationValue(TemplateId); 792 if (TemplateKWLoc.isValid()) 793 Tok.setLocation(TemplateKWLoc); 794 else 795 Tok.setLocation(TemplateNameLoc); 796 797 TemplateArgsPtr.release(); 798 } 799 800 // Common fields for the annotation token 801 Tok.setAnnotationEndLoc(RAngleLoc); 802 803 // In case the tokens were cached, have Preprocessor replace them with the 804 // annotation token. 805 PP.AnnotateCachedTokens(Tok); 806 return false; 807} 808 809/// \brief Replaces a template-id annotation token with a type 810/// annotation token. 811/// 812/// If there was a failure when forming the type from the template-id, 813/// a type annotation token will still be created, but will have a 814/// NULL type pointer to signify an error. 815void Parser::AnnotateTemplateIdTokenAsType(const CXXScopeSpec *SS) { 816 assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens"); 817 818 TemplateIdAnnotation *TemplateId 819 = static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue()); 820 assert((TemplateId->Kind == TNK_Type_template || 821 TemplateId->Kind == TNK_Dependent_template_name) && 822 "Only works for type and dependent templates"); 823 824 ASTTemplateArgsPtr TemplateArgsPtr(Actions, 825 TemplateId->getTemplateArgs(), 826 TemplateId->NumArgs); 827 828 Action::TypeResult Type 829 = Actions.ActOnTemplateIdType(TemplateTy::make(TemplateId->Template), 830 TemplateId->TemplateNameLoc, 831 TemplateId->LAngleLoc, 832 TemplateArgsPtr, 833 TemplateId->RAngleLoc); 834 // Create the new "type" annotation token. 835 Tok.setKind(tok::annot_typename); 836 Tok.setAnnotationValue(Type.isInvalid()? 0 : Type.get()); 837 if (SS && SS->isNotEmpty()) // it was a C++ qualified type name. 838 Tok.setLocation(SS->getBeginLoc()); 839 // End location stays the same 840 841 // Replace the template-id annotation token, and possible the scope-specifier 842 // that precedes it, with the typename annotation token. 843 PP.AnnotateCachedTokens(Tok); 844 TemplateId->Destroy(); 845} 846 847/// \brief Determine whether the given token can end a template argument. 848static bool isEndOfTemplateArgument(Token Tok) { 849 return Tok.is(tok::comma) || Tok.is(tok::greater) || 850 Tok.is(tok::greatergreater); 851} 852 853/// \brief Parse a C++ template template argument. 854ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() { 855 if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) && 856 !Tok.is(tok::annot_cxxscope)) 857 return ParsedTemplateArgument(); 858 859 // C++0x [temp.arg.template]p1: 860 // A template-argument for a template template-parameter shall be the name 861 // of a class template or a template alias, expressed as id-expression. 862 // 863 // We parse an id-expression that refers to a class template or template 864 // alias. The grammar we parse is: 865 // 866 // nested-name-specifier[opt] template[opt] identifier 867 // 868 // followed by a token that terminates a template argument, such as ',', 869 // '>', or (in some cases) '>>'. 870 CXXScopeSpec SS; // nested-name-specifier, if present 871 ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/0, 872 /*EnteringContext=*/false); 873 874 if (SS.isSet() && Tok.is(tok::kw_template)) { 875 // Parse the optional 'template' keyword following the 876 // nested-name-specifier. 877 SourceLocation TemplateLoc = ConsumeToken(); 878 879 if (Tok.is(tok::identifier)) { 880 // We appear to have a dependent template name. 881 UnqualifiedId Name; 882 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 883 ConsumeToken(); // the identifier 884 885 // If the next token signals the end of a template argument, 886 // then we have a dependent template name that could be a template 887 // template argument. 888 if (isEndOfTemplateArgument(Tok)) { 889 TemplateTy Template 890 = Actions.ActOnDependentTemplateName(TemplateLoc, SS, Name, 891 /*ObjectType=*/0, 892 /*EnteringContext=*/false); 893 if (Template.get()) 894 return ParsedTemplateArgument(SS, Template, Name.StartLocation); 895 } 896 } 897 } else if (Tok.is(tok::identifier)) { 898 // We may have a (non-dependent) template name. 899 TemplateTy Template; 900 UnqualifiedId Name; 901 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 902 ConsumeToken(); // the identifier 903 904 if (isEndOfTemplateArgument(Tok)) { 905 bool MemberOfUnknownSpecialization; 906 TemplateNameKind TNK = Actions.isTemplateName(CurScope, SS, Name, 907 /*ObjectType=*/0, 908 /*EnteringContext=*/false, 909 Template, 910 MemberOfUnknownSpecialization); 911 if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) { 912 // We have an id-expression that refers to a class template or 913 // (C++0x) template alias. 914 return ParsedTemplateArgument(SS, Template, Name.StartLocation); 915 } 916 } 917 } 918 919 // We don't have a template template argument. 920 return ParsedTemplateArgument(); 921} 922 923/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). 924/// 925/// template-argument: [C++ 14.2] 926/// constant-expression 927/// type-id 928/// id-expression 929ParsedTemplateArgument Parser::ParseTemplateArgument() { 930 // C++ [temp.arg]p2: 931 // In a template-argument, an ambiguity between a type-id and an 932 // expression is resolved to a type-id, regardless of the form of 933 // the corresponding template-parameter. 934 // 935 // Therefore, we initially try to parse a type-id. 936 if (isCXXTypeId(TypeIdAsTemplateArgument)) { 937 SourceLocation Loc = Tok.getLocation(); 938 TypeResult TypeArg = ParseTypeName(); 939 if (TypeArg.isInvalid()) 940 return ParsedTemplateArgument(); 941 942 return ParsedTemplateArgument(ParsedTemplateArgument::Type, TypeArg.get(), 943 Loc); 944 } 945 946 // Try to parse a template template argument. 947 { 948 TentativeParsingAction TPA(*this); 949 950 ParsedTemplateArgument TemplateTemplateArgument 951 = ParseTemplateTemplateArgument(); 952 if (!TemplateTemplateArgument.isInvalid()) { 953 TPA.Commit(); 954 return TemplateTemplateArgument; 955 } 956 957 // Revert this tentative parse to parse a non-type template argument. 958 TPA.Revert(); 959 } 960 961 // Parse a non-type template argument. 962 SourceLocation Loc = Tok.getLocation(); 963 OwningExprResult ExprArg = ParseConstantExpression(); 964 if (ExprArg.isInvalid() || !ExprArg.get()) 965 return ParsedTemplateArgument(); 966 967 return ParsedTemplateArgument(ParsedTemplateArgument::NonType, 968 ExprArg.release(), Loc); 969} 970 971/// \brief Determine whether the current tokens can only be parsed as a 972/// template argument list (starting with the '<') and never as a '<' 973/// expression. 974bool Parser::IsTemplateArgumentList(unsigned Skip) { 975 struct AlwaysRevertAction : TentativeParsingAction { 976 AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { } 977 ~AlwaysRevertAction() { Revert(); } 978 } Tentative(*this); 979 980 while (Skip) { 981 ConsumeToken(); 982 --Skip; 983 } 984 985 // '<' 986 if (!Tok.is(tok::less)) 987 return false; 988 ConsumeToken(); 989 990 // An empty template argument list. 991 if (Tok.is(tok::greater)) 992 return true; 993 994 // See whether we have declaration specifiers, which indicate a type. 995 while (isCXXDeclarationSpecifier() == TPResult::True()) 996 ConsumeToken(); 997 998 // If we have a '>' or a ',' then this is a template argument list. 999 return Tok.is(tok::greater) || Tok.is(tok::comma); 1000} 1001 1002/// ParseTemplateArgumentList - Parse a C++ template-argument-list 1003/// (C++ [temp.names]). Returns true if there was an error. 1004/// 1005/// template-argument-list: [C++ 14.2] 1006/// template-argument 1007/// template-argument-list ',' template-argument 1008bool 1009Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) { 1010 while (true) { 1011 ParsedTemplateArgument Arg = ParseTemplateArgument(); 1012 if (Arg.isInvalid()) { 1013 SkipUntil(tok::comma, tok::greater, true, true); 1014 return true; 1015 } 1016 1017 // Save this template argument. 1018 TemplateArgs.push_back(Arg); 1019 1020 // If the next token is a comma, consume it and keep reading 1021 // arguments. 1022 if (Tok.isNot(tok::comma)) break; 1023 1024 // Consume the comma. 1025 ConsumeToken(); 1026 } 1027 1028 return false; 1029} 1030 1031/// \brief Parse a C++ explicit template instantiation 1032/// (C++ [temp.explicit]). 1033/// 1034/// explicit-instantiation: 1035/// 'extern' [opt] 'template' declaration 1036/// 1037/// Note that the 'extern' is a GNU extension and C++0x feature. 1038Parser::DeclPtrTy 1039Parser::ParseExplicitInstantiation(SourceLocation ExternLoc, 1040 SourceLocation TemplateLoc, 1041 SourceLocation &DeclEnd) { 1042 return ParseSingleDeclarationAfterTemplate(Declarator::FileContext, 1043 ParsedTemplateInfo(ExternLoc, 1044 TemplateLoc), 1045 DeclEnd, AS_none); 1046} 1047