ParseTemplate.cpp revision 199990
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" 19using namespace clang; 20 21/// \brief Parse a template declaration, explicit instantiation, or 22/// explicit specialization. 23Parser::DeclPtrTy 24Parser::ParseDeclarationStartingWithTemplate(unsigned Context, 25 SourceLocation &DeclEnd, 26 AccessSpecifier AS) { 27 if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) 28 return ParseExplicitInstantiation(SourceLocation(), ConsumeToken(), 29 DeclEnd); 30 31 return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS); 32} 33 34/// \brief RAII class that manages the template parameter depth. 35namespace { 36 class TemplateParameterDepthCounter { 37 unsigned &Depth; 38 unsigned AddedLevels; 39 40 public: 41 explicit TemplateParameterDepthCounter(unsigned &Depth) 42 : Depth(Depth), AddedLevels(0) { } 43 44 ~TemplateParameterDepthCounter() { 45 Depth -= AddedLevels; 46 } 47 48 void operator++() { 49 ++Depth; 50 ++AddedLevels; 51 } 52 53 operator unsigned() const { return Depth; } 54 }; 55} 56 57/// \brief Parse a template declaration or an explicit specialization. 58/// 59/// Template declarations include one or more template parameter lists 60/// and either the function or class template declaration. Explicit 61/// specializations contain one or more 'template < >' prefixes 62/// followed by a (possibly templated) declaration. Since the 63/// syntactic form of both features is nearly identical, we parse all 64/// of the template headers together and let semantic analysis sort 65/// the declarations from the explicit specializations. 66/// 67/// template-declaration: [C++ temp] 68/// 'export'[opt] 'template' '<' template-parameter-list '>' declaration 69/// 70/// explicit-specialization: [ C++ temp.expl.spec] 71/// 'template' '<' '>' declaration 72Parser::DeclPtrTy 73Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context, 74 SourceLocation &DeclEnd, 75 AccessSpecifier AS) { 76 assert((Tok.is(tok::kw_export) || Tok.is(tok::kw_template)) && 77 "Token does not start a template declaration."); 78 79 // Enter template-parameter scope. 80 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 81 82 // Parse multiple levels of template headers within this template 83 // parameter scope, e.g., 84 // 85 // template<typename T> 86 // template<typename U> 87 // class A<T>::B { ... }; 88 // 89 // We parse multiple levels non-recursively so that we can build a 90 // single data structure containing all of the template parameter 91 // lists to easily differentiate between the case above and: 92 // 93 // template<typename T> 94 // class A { 95 // template<typename U> class B; 96 // }; 97 // 98 // In the first case, the action for declaring A<T>::B receives 99 // both template parameter lists. In the second case, the action for 100 // defining A<T>::B receives just the inner template parameter list 101 // (and retrieves the outer template parameter list from its 102 // context). 103 bool isSpecialization = true; 104 bool LastParamListWasEmpty = false; 105 TemplateParameterLists ParamLists; 106 TemplateParameterDepthCounter Depth(TemplateParameterDepth); 107 do { 108 // Consume the 'export', if any. 109 SourceLocation ExportLoc; 110 if (Tok.is(tok::kw_export)) { 111 ExportLoc = ConsumeToken(); 112 } 113 114 // Consume the 'template', which should be here. 115 SourceLocation TemplateLoc; 116 if (Tok.is(tok::kw_template)) { 117 TemplateLoc = ConsumeToken(); 118 } else { 119 Diag(Tok.getLocation(), diag::err_expected_template); 120 return DeclPtrTy(); 121 } 122 123 // Parse the '<' template-parameter-list '>' 124 SourceLocation LAngleLoc, RAngleLoc; 125 TemplateParameterList TemplateParams; 126 if (ParseTemplateParameters(Depth, TemplateParams, LAngleLoc, 127 RAngleLoc)) { 128 // Skip until the semi-colon or a }. 129 SkipUntil(tok::r_brace, true, true); 130 if (Tok.is(tok::semi)) 131 ConsumeToken(); 132 return DeclPtrTy(); 133 } 134 135 ParamLists.push_back( 136 Actions.ActOnTemplateParameterList(Depth, ExportLoc, 137 TemplateLoc, LAngleLoc, 138 TemplateParams.data(), 139 TemplateParams.size(), RAngleLoc)); 140 141 if (!TemplateParams.empty()) { 142 isSpecialization = false; 143 ++Depth; 144 } else { 145 LastParamListWasEmpty = true; 146 } 147 } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template)); 148 149 // Parse the actual template declaration. 150 return ParseSingleDeclarationAfterTemplate(Context, 151 ParsedTemplateInfo(&ParamLists, 152 isSpecialization, 153 LastParamListWasEmpty), 154 DeclEnd, AS); 155} 156 157/// \brief Parse a single declaration that declares a template, 158/// template specialization, or explicit instantiation of a template. 159/// 160/// \param TemplateParams if non-NULL, the template parameter lists 161/// that preceded this declaration. In this case, the declaration is a 162/// template declaration, out-of-line definition of a template, or an 163/// explicit template specialization. When NULL, the declaration is an 164/// explicit template instantiation. 165/// 166/// \param TemplateLoc when TemplateParams is NULL, the location of 167/// the 'template' keyword that indicates that we have an explicit 168/// template instantiation. 169/// 170/// \param DeclEnd will receive the source location of the last token 171/// within this declaration. 172/// 173/// \param AS the access specifier associated with this 174/// declaration. Will be AS_none for namespace-scope declarations. 175/// 176/// \returns the new declaration. 177Parser::DeclPtrTy 178Parser::ParseSingleDeclarationAfterTemplate( 179 unsigned Context, 180 const ParsedTemplateInfo &TemplateInfo, 181 SourceLocation &DeclEnd, 182 AccessSpecifier AS) { 183 assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate && 184 "Template information required"); 185 186 if (Context == Declarator::MemberContext) { 187 // We are parsing a member template. 188 ParseCXXClassMemberDeclaration(AS, TemplateInfo); 189 return DeclPtrTy::make((void*)0); 190 } 191 192 // Parse the declaration specifiers. 193 ParsingDeclSpec DS(*this); 194 195 if (getLang().CPlusPlus0x && isCXX0XAttributeSpecifier()) 196 DS.AddAttributes(ParseCXX0XAttributes().AttrList); 197 198 ParseDeclarationSpecifiers(DS, TemplateInfo, AS); 199 200 if (Tok.is(tok::semi)) { 201 DeclEnd = ConsumeToken(); 202 DeclPtrTy Decl = Actions.ParsedFreeStandingDeclSpec(CurScope, DS); 203 DS.complete(Decl); 204 return Decl; 205 } 206 207 // Parse the declarator. 208 ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context); 209 ParseDeclarator(DeclaratorInfo); 210 // Error parsing the declarator? 211 if (!DeclaratorInfo.hasName()) { 212 // If so, skip until the semi-colon or a }. 213 SkipUntil(tok::r_brace, true, true); 214 if (Tok.is(tok::semi)) 215 ConsumeToken(); 216 return DeclPtrTy(); 217 } 218 219 // If we have a declaration or declarator list, handle it. 220 if (isDeclarationAfterDeclarator()) { 221 // Parse this declaration. 222 DeclPtrTy ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo, 223 TemplateInfo); 224 225 if (Tok.is(tok::comma)) { 226 Diag(Tok, diag::err_multiple_template_declarators) 227 << (int)TemplateInfo.Kind; 228 SkipUntil(tok::semi, true, false); 229 return ThisDecl; 230 } 231 232 // Eat the semi colon after the declaration. 233 ExpectAndConsume(tok::semi, diag::err_expected_semi_declaration); 234 DS.complete(ThisDecl); 235 return ThisDecl; 236 } 237 238 if (DeclaratorInfo.isFunctionDeclarator() && 239 isStartOfFunctionDefinition()) { 240 if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) { 241 Diag(Tok, diag::err_function_declared_typedef); 242 243 if (Tok.is(tok::l_brace)) { 244 // This recovery skips the entire function body. It would be nice 245 // to simply call ParseFunctionDefinition() below, however Sema 246 // assumes the declarator represents a function, not a typedef. 247 ConsumeBrace(); 248 SkipUntil(tok::r_brace, true); 249 } else { 250 SkipUntil(tok::semi); 251 } 252 return DeclPtrTy(); 253 } 254 return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo); 255 } 256 257 if (DeclaratorInfo.isFunctionDeclarator()) 258 Diag(Tok, diag::err_expected_fn_body); 259 else 260 Diag(Tok, diag::err_invalid_token_after_toplevel_declarator); 261 SkipUntil(tok::semi); 262 return DeclPtrTy(); 263} 264 265/// ParseTemplateParameters - Parses a template-parameter-list enclosed in 266/// angle brackets. Depth is the depth of this template-parameter-list, which 267/// is the number of template headers directly enclosing this template header. 268/// TemplateParams is the current list of template parameters we're building. 269/// The template parameter we parse will be added to this list. LAngleLoc and 270/// RAngleLoc will receive the positions of the '<' and '>', respectively, 271/// that enclose this template parameter list. 272/// 273/// \returns true if an error occurred, false otherwise. 274bool Parser::ParseTemplateParameters(unsigned Depth, 275 TemplateParameterList &TemplateParams, 276 SourceLocation &LAngleLoc, 277 SourceLocation &RAngleLoc) { 278 // Get the template parameter list. 279 if (!Tok.is(tok::less)) { 280 Diag(Tok.getLocation(), diag::err_expected_less_after) << "template"; 281 return true; 282 } 283 LAngleLoc = ConsumeToken(); 284 285 // Try to parse the template parameter list. 286 if (Tok.is(tok::greater)) 287 RAngleLoc = ConsumeToken(); 288 else if (ParseTemplateParameterList(Depth, TemplateParams)) { 289 if (!Tok.is(tok::greater)) { 290 Diag(Tok.getLocation(), diag::err_expected_greater); 291 return true; 292 } 293 RAngleLoc = ConsumeToken(); 294 } 295 return false; 296} 297 298/// ParseTemplateParameterList - Parse a template parameter list. If 299/// the parsing fails badly (i.e., closing bracket was left out), this 300/// will try to put the token stream in a reasonable position (closing 301/// a statement, etc.) and return false. 302/// 303/// template-parameter-list: [C++ temp] 304/// template-parameter 305/// template-parameter-list ',' template-parameter 306bool 307Parser::ParseTemplateParameterList(unsigned Depth, 308 TemplateParameterList &TemplateParams) { 309 while (1) { 310 if (DeclPtrTy TmpParam 311 = ParseTemplateParameter(Depth, TemplateParams.size())) { 312 TemplateParams.push_back(TmpParam); 313 } else { 314 // If we failed to parse a template parameter, skip until we find 315 // a comma or closing brace. 316 SkipUntil(tok::comma, tok::greater, true, true); 317 } 318 319 // Did we find a comma or the end of the template parmeter list? 320 if (Tok.is(tok::comma)) { 321 ConsumeToken(); 322 } else if (Tok.is(tok::greater)) { 323 // Don't consume this... that's done by template parser. 324 break; 325 } else { 326 // Somebody probably forgot to close the template. Skip ahead and 327 // try to get out of the expression. This error is currently 328 // subsumed by whatever goes on in ParseTemplateParameter. 329 // TODO: This could match >>, and it would be nice to avoid those 330 // silly errors with template <vec<T>>. 331 // Diag(Tok.getLocation(), diag::err_expected_comma_greater); 332 SkipUntil(tok::greater, true, true); 333 return false; 334 } 335 } 336 return true; 337} 338 339/// \brief Determine whether the parser is at the start of a template 340/// type parameter. 341bool Parser::isStartOfTemplateTypeParameter() { 342 if (Tok.is(tok::kw_class)) 343 return true; 344 345 if (Tok.isNot(tok::kw_typename)) 346 return false; 347 348 // C++ [temp.param]p2: 349 // There is no semantic difference between class and typename in a 350 // template-parameter. typename followed by an unqualified-id 351 // names a template type parameter. typename followed by a 352 // qualified-id denotes the type in a non-type 353 // parameter-declaration. 354 Token Next = NextToken(); 355 356 // If we have an identifier, skip over it. 357 if (Next.getKind() == tok::identifier) 358 Next = GetLookAheadToken(2); 359 360 switch (Next.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 default: 369 return false; 370 } 371} 372 373/// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]). 374/// 375/// template-parameter: [C++ temp.param] 376/// type-parameter 377/// parameter-declaration 378/// 379/// type-parameter: (see below) 380/// 'class' ...[opt][C++0x] identifier[opt] 381/// 'class' identifier[opt] '=' type-id 382/// 'typename' ...[opt][C++0x] identifier[opt] 383/// 'typename' identifier[opt] '=' type-id 384/// 'template' ...[opt][C++0x] '<' template-parameter-list '>' 'class' identifier[opt] 385/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression 386Parser::DeclPtrTy 387Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { 388 if (isStartOfTemplateTypeParameter()) 389 return ParseTypeParameter(Depth, Position); 390 391 if (Tok.is(tok::kw_template)) 392 return ParseTemplateTemplateParameter(Depth, Position); 393 394 // If it's none of the above, then it must be a parameter declaration. 395 // NOTE: This will pick up errors in the closure of the template parameter 396 // list (e.g., template < ; Check here to implement >> style closures. 397 return ParseNonTypeTemplateParameter(Depth, Position); 398} 399 400/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]). 401/// Other kinds of template parameters are parsed in 402/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter. 403/// 404/// type-parameter: [C++ temp.param] 405/// 'class' ...[opt][C++0x] identifier[opt] 406/// 'class' identifier[opt] '=' type-id 407/// 'typename' ...[opt][C++0x] identifier[opt] 408/// 'typename' identifier[opt] '=' type-id 409Parser::DeclPtrTy Parser::ParseTypeParameter(unsigned Depth, unsigned Position){ 410 assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) && 411 "A type-parameter starts with 'class' or 'typename'"); 412 413 // Consume the 'class' or 'typename' keyword. 414 bool TypenameKeyword = Tok.is(tok::kw_typename); 415 SourceLocation KeyLoc = ConsumeToken(); 416 417 // Grab the ellipsis (if given). 418 bool Ellipsis = false; 419 SourceLocation EllipsisLoc; 420 if (Tok.is(tok::ellipsis)) { 421 Ellipsis = true; 422 EllipsisLoc = ConsumeToken(); 423 424 if (!getLang().CPlusPlus0x) 425 Diag(EllipsisLoc, diag::err_variadic_templates); 426 } 427 428 // Grab the template parameter name (if given) 429 SourceLocation NameLoc; 430 IdentifierInfo* ParamName = 0; 431 if (Tok.is(tok::identifier)) { 432 ParamName = Tok.getIdentifierInfo(); 433 NameLoc = ConsumeToken(); 434 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || 435 Tok.is(tok::greater)) { 436 // Unnamed template parameter. Don't have to do anything here, just 437 // don't consume this token. 438 } else { 439 Diag(Tok.getLocation(), diag::err_expected_ident); 440 return DeclPtrTy(); 441 } 442 443 DeclPtrTy TypeParam = Actions.ActOnTypeParameter(CurScope, TypenameKeyword, 444 Ellipsis, EllipsisLoc, 445 KeyLoc, ParamName, NameLoc, 446 Depth, Position); 447 448 // Grab a default type id (if given). 449 if (Tok.is(tok::equal)) { 450 SourceLocation EqualLoc = ConsumeToken(); 451 SourceLocation DefaultLoc = Tok.getLocation(); 452 TypeResult DefaultType = ParseTypeName(); 453 if (!DefaultType.isInvalid()) 454 Actions.ActOnTypeParameterDefault(TypeParam, EqualLoc, DefaultLoc, 455 DefaultType.get()); 456 } 457 458 return TypeParam; 459} 460 461/// ParseTemplateTemplateParameter - Handle the parsing of template 462/// template parameters. 463/// 464/// type-parameter: [C++ temp.param] 465/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] 466/// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression 467Parser::DeclPtrTy 468Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { 469 assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); 470 471 // Handle the template <...> part. 472 SourceLocation TemplateLoc = ConsumeToken(); 473 TemplateParameterList TemplateParams; 474 SourceLocation LAngleLoc, RAngleLoc; 475 { 476 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 477 if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, 478 RAngleLoc)) { 479 return DeclPtrTy(); 480 } 481 } 482 483 // Generate a meaningful error if the user forgot to put class before the 484 // identifier, comma, or greater. 485 if (!Tok.is(tok::kw_class)) { 486 Diag(Tok.getLocation(), diag::err_expected_class_before) 487 << PP.getSpelling(Tok); 488 return DeclPtrTy(); 489 } 490 SourceLocation ClassLoc = ConsumeToken(); 491 492 // Get the identifier, if given. 493 SourceLocation NameLoc; 494 IdentifierInfo* ParamName = 0; 495 if (Tok.is(tok::identifier)) { 496 ParamName = Tok.getIdentifierInfo(); 497 NameLoc = ConsumeToken(); 498 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater)) { 499 // Unnamed template parameter. Don't have to do anything here, just 500 // don't consume this token. 501 } else { 502 Diag(Tok.getLocation(), diag::err_expected_ident); 503 return DeclPtrTy(); 504 } 505 506 TemplateParamsTy *ParamList = 507 Actions.ActOnTemplateParameterList(Depth, SourceLocation(), 508 TemplateLoc, LAngleLoc, 509 &TemplateParams[0], 510 TemplateParams.size(), 511 RAngleLoc); 512 513 Parser::DeclPtrTy Param 514 = Actions.ActOnTemplateTemplateParameter(CurScope, TemplateLoc, 515 ParamList, ParamName, 516 NameLoc, Depth, Position); 517 518 // Get the a default value, if given. 519 if (Tok.is(tok::equal)) { 520 SourceLocation EqualLoc = ConsumeToken(); 521 ParsedTemplateArgument Default = ParseTemplateTemplateArgument(); 522 if (Default.isInvalid()) { 523 Diag(Tok.getLocation(), 524 diag::err_default_template_template_parameter_not_template); 525 static tok::TokenKind EndToks[] = { 526 tok::comma, tok::greater, tok::greatergreater 527 }; 528 SkipUntil(EndToks, 3, true, true); 529 return Param; 530 } else if (Param) 531 Actions.ActOnTemplateTemplateParameterDefault(Param, EqualLoc, Default); 532 } 533 534 return Param; 535} 536 537/// ParseNonTypeTemplateParameter - Handle the parsing of non-type 538/// template parameters (e.g., in "template<int Size> class array;"). 539/// 540/// template-parameter: 541/// ... 542/// parameter-declaration 543/// 544/// NOTE: It would be ideal to simply call out to ParseParameterDeclaration(), 545/// but that didn't work out to well. Instead, this tries to recrate the basic 546/// parsing of parameter declarations, but tries to constrain it for template 547/// parameters. 548/// FIXME: We need to make a ParseParameterDeclaration that works for 549/// non-type template parameters and normal function parameters. 550Parser::DeclPtrTy 551Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { 552 SourceLocation StartLoc = Tok.getLocation(); 553 554 // Parse the declaration-specifiers (i.e., the type). 555 // FIXME: The type should probably be restricted in some way... Not all 556 // declarators (parts of declarators?) are accepted for parameters. 557 DeclSpec DS; 558 ParseDeclarationSpecifiers(DS); 559 560 // Parse this as a typename. 561 Declarator ParamDecl(DS, Declarator::TemplateParamContext); 562 ParseDeclarator(ParamDecl); 563 if (DS.getTypeSpecType() == DeclSpec::TST_unspecified && !DS.getTypeRep()) { 564 // This probably shouldn't happen - and it's more of a Sema thing, but 565 // basically we didn't parse the type name because we couldn't associate 566 // it with an AST node. we should just skip to the comma or greater. 567 // TODO: This is currently a placeholder for some kind of Sema Error. 568 Diag(Tok.getLocation(), diag::err_parse_error); 569 SkipUntil(tok::comma, tok::greater, true, true); 570 return DeclPtrTy(); 571 } 572 573 // Create the parameter. 574 DeclPtrTy Param = Actions.ActOnNonTypeTemplateParameter(CurScope, ParamDecl, 575 Depth, Position); 576 577 // If there is a default value, parse it. 578 if (Tok.is(tok::equal)) { 579 SourceLocation EqualLoc = ConsumeToken(); 580 581 // C++ [temp.param]p15: 582 // When parsing a default template-argument for a non-type 583 // template-parameter, the first non-nested > is taken as the 584 // end of the template-parameter-list rather than a greater-than 585 // operator. 586 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 587 588 OwningExprResult DefaultArg = ParseAssignmentExpression(); 589 if (DefaultArg.isInvalid()) 590 SkipUntil(tok::comma, tok::greater, true, true); 591 else if (Param) 592 Actions.ActOnNonTypeTemplateParameterDefault(Param, EqualLoc, 593 move(DefaultArg)); 594 } 595 596 return Param; 597} 598 599/// \brief Parses a template-id that after the template name has 600/// already been parsed. 601/// 602/// This routine takes care of parsing the enclosed template argument 603/// list ('<' template-parameter-list [opt] '>') and placing the 604/// results into a form that can be transferred to semantic analysis. 605/// 606/// \param Template the template declaration produced by isTemplateName 607/// 608/// \param TemplateNameLoc the source location of the template name 609/// 610/// \param SS if non-NULL, the nested-name-specifier preceding the 611/// template name. 612/// 613/// \param ConsumeLastToken if true, then we will consume the last 614/// token that forms the template-id. Otherwise, we will leave the 615/// last token in the stream (e.g., so that it can be replaced with an 616/// annotation token). 617bool 618Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template, 619 SourceLocation TemplateNameLoc, 620 const CXXScopeSpec *SS, 621 bool ConsumeLastToken, 622 SourceLocation &LAngleLoc, 623 TemplateArgList &TemplateArgs, 624 SourceLocation &RAngleLoc) { 625 assert(Tok.is(tok::less) && "Must have already parsed the template-name"); 626 627 // Consume the '<'. 628 LAngleLoc = ConsumeToken(); 629 630 // Parse the optional template-argument-list. 631 bool Invalid = false; 632 { 633 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 634 if (Tok.isNot(tok::greater)) 635 Invalid = ParseTemplateArgumentList(TemplateArgs); 636 637 if (Invalid) { 638 // Try to find the closing '>'. 639 SkipUntil(tok::greater, true, !ConsumeLastToken); 640 641 return true; 642 } 643 } 644 645 if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) 646 return true; 647 648 // Determine the location of the '>' or '>>'. Only consume this 649 // token if the caller asked us to. 650 RAngleLoc = Tok.getLocation(); 651 652 if (Tok.is(tok::greatergreater)) { 653 if (!getLang().CPlusPlus0x) { 654 const char *ReplaceStr = "> >"; 655 if (NextToken().is(tok::greater) || NextToken().is(tok::greatergreater)) 656 ReplaceStr = "> > "; 657 658 Diag(Tok.getLocation(), diag::err_two_right_angle_brackets_need_space) 659 << CodeModificationHint::CreateReplacement( 660 SourceRange(Tok.getLocation()), ReplaceStr); 661 } 662 663 Tok.setKind(tok::greater); 664 if (!ConsumeLastToken) { 665 // Since we're not supposed to consume the '>>' token, we need 666 // to insert a second '>' token after the first. 667 PP.EnterToken(Tok); 668 } 669 } else if (ConsumeLastToken) 670 ConsumeToken(); 671 672 return false; 673} 674 675/// \brief Replace the tokens that form a simple-template-id with an 676/// annotation token containing the complete template-id. 677/// 678/// The first token in the stream must be the name of a template that 679/// is followed by a '<'. This routine will parse the complete 680/// simple-template-id and replace the tokens with a single annotation 681/// token with one of two different kinds: if the template-id names a 682/// type (and \p AllowTypeAnnotation is true), the annotation token is 683/// a type annotation that includes the optional nested-name-specifier 684/// (\p SS). Otherwise, the annotation token is a template-id 685/// annotation that does not include the optional 686/// nested-name-specifier. 687/// 688/// \param Template the declaration of the template named by the first 689/// token (an identifier), as returned from \c Action::isTemplateName(). 690/// 691/// \param TemplateNameKind the kind of template that \p Template 692/// refers to, as returned from \c Action::isTemplateName(). 693/// 694/// \param SS if non-NULL, the nested-name-specifier that precedes 695/// this template name. 696/// 697/// \param TemplateKWLoc if valid, specifies that this template-id 698/// annotation was preceded by the 'template' keyword and gives the 699/// location of that keyword. If invalid (the default), then this 700/// template-id was not preceded by a 'template' keyword. 701/// 702/// \param AllowTypeAnnotation if true (the default), then a 703/// simple-template-id that refers to a class template, template 704/// template parameter, or other template that produces a type will be 705/// replaced with a type annotation token. Otherwise, the 706/// simple-template-id is always replaced with a template-id 707/// annotation token. 708/// 709/// If an unrecoverable parse error occurs and no annotation token can be 710/// formed, this function returns true. 711/// 712bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK, 713 const CXXScopeSpec *SS, 714 UnqualifiedId &TemplateName, 715 SourceLocation TemplateKWLoc, 716 bool AllowTypeAnnotation) { 717 assert(getLang().CPlusPlus && "Can only annotate template-ids in C++"); 718 assert(Template && Tok.is(tok::less) && 719 "Parser isn't at the beginning of a template-id"); 720 721 // Consume the template-name. 722 SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin(); 723 724 // Parse the enclosed template argument list. 725 SourceLocation LAngleLoc, RAngleLoc; 726 TemplateArgList TemplateArgs; 727 bool Invalid = ParseTemplateIdAfterTemplateName(Template, 728 TemplateNameLoc, 729 SS, false, LAngleLoc, 730 TemplateArgs, 731 RAngleLoc); 732 733 if (Invalid) { 734 // If we failed to parse the template ID but skipped ahead to a >, we're not 735 // going to be able to form a token annotation. Eat the '>' if present. 736 if (Tok.is(tok::greater)) 737 ConsumeToken(); 738 return true; 739 } 740 741 ASTTemplateArgsPtr TemplateArgsPtr(Actions, TemplateArgs.data(), 742 TemplateArgs.size()); 743 744 // Build the annotation token. 745 if (TNK == TNK_Type_template && AllowTypeAnnotation) { 746 Action::TypeResult Type 747 = Actions.ActOnTemplateIdType(Template, TemplateNameLoc, 748 LAngleLoc, TemplateArgsPtr, 749 RAngleLoc); 750 if (Type.isInvalid()) { 751 // If we failed to parse the template ID but skipped ahead to a >, we're not 752 // going to be able to form a token annotation. Eat the '>' if present. 753 if (Tok.is(tok::greater)) 754 ConsumeToken(); 755 return true; 756 } 757 758 Tok.setKind(tok::annot_typename); 759 Tok.setAnnotationValue(Type.get()); 760 if (SS && SS->isNotEmpty()) 761 Tok.setLocation(SS->getBeginLoc()); 762 else if (TemplateKWLoc.isValid()) 763 Tok.setLocation(TemplateKWLoc); 764 else 765 Tok.setLocation(TemplateNameLoc); 766 } else { 767 // Build a template-id annotation token that can be processed 768 // later. 769 Tok.setKind(tok::annot_template_id); 770 TemplateIdAnnotation *TemplateId 771 = TemplateIdAnnotation::Allocate(TemplateArgs.size()); 772 TemplateId->TemplateNameLoc = TemplateNameLoc; 773 if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) { 774 TemplateId->Name = TemplateName.Identifier; 775 TemplateId->Operator = OO_None; 776 } else { 777 TemplateId->Name = 0; 778 TemplateId->Operator = TemplateName.OperatorFunctionId.Operator; 779 } 780 TemplateId->Template = Template.getAs<void*>(); 781 TemplateId->Kind = TNK; 782 TemplateId->LAngleLoc = LAngleLoc; 783 TemplateId->RAngleLoc = RAngleLoc; 784 ParsedTemplateArgument *Args = TemplateId->getTemplateArgs(); 785 for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) 786 Args[Arg] = TemplateArgs[Arg]; 787 Tok.setAnnotationValue(TemplateId); 788 if (TemplateKWLoc.isValid()) 789 Tok.setLocation(TemplateKWLoc); 790 else 791 Tok.setLocation(TemplateNameLoc); 792 793 TemplateArgsPtr.release(); 794 } 795 796 // Common fields for the annotation token 797 Tok.setAnnotationEndLoc(RAngleLoc); 798 799 // In case the tokens were cached, have Preprocessor replace them with the 800 // annotation token. 801 PP.AnnotateCachedTokens(Tok); 802 return false; 803} 804 805/// \brief Replaces a template-id annotation token with a type 806/// annotation token. 807/// 808/// If there was a failure when forming the type from the template-id, 809/// a type annotation token will still be created, but will have a 810/// NULL type pointer to signify an error. 811void Parser::AnnotateTemplateIdTokenAsType(const CXXScopeSpec *SS) { 812 assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens"); 813 814 TemplateIdAnnotation *TemplateId 815 = static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue()); 816 assert((TemplateId->Kind == TNK_Type_template || 817 TemplateId->Kind == TNK_Dependent_template_name) && 818 "Only works for type and dependent templates"); 819 820 ASTTemplateArgsPtr TemplateArgsPtr(Actions, 821 TemplateId->getTemplateArgs(), 822 TemplateId->NumArgs); 823 824 Action::TypeResult Type 825 = Actions.ActOnTemplateIdType(TemplateTy::make(TemplateId->Template), 826 TemplateId->TemplateNameLoc, 827 TemplateId->LAngleLoc, 828 TemplateArgsPtr, 829 TemplateId->RAngleLoc); 830 // Create the new "type" annotation token. 831 Tok.setKind(tok::annot_typename); 832 Tok.setAnnotationValue(Type.isInvalid()? 0 : Type.get()); 833 if (SS && SS->isNotEmpty()) // it was a C++ qualified type name. 834 Tok.setLocation(SS->getBeginLoc()); 835 Tok.setAnnotationEndLoc(TemplateId->TemplateNameLoc); 836 837 // Replace the template-id annotation token, and possible the scope-specifier 838 // that precedes it, with the typename annotation token. 839 PP.AnnotateCachedTokens(Tok); 840 TemplateId->Destroy(); 841} 842 843/// \brief Determine whether the given token can end a template argument. 844static bool isEndOfTemplateArgument(Token Tok) { 845 return Tok.is(tok::comma) || Tok.is(tok::greater) || 846 Tok.is(tok::greatergreater); 847} 848 849/// \brief Parse a C++ template template argument. 850ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() { 851 if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) && 852 !Tok.is(tok::annot_cxxscope)) 853 return ParsedTemplateArgument(); 854 855 // C++0x [temp.arg.template]p1: 856 // A template-argument for a template template-parameter shall be the name 857 // of a class template or a template alias, expressed as id-expression. 858 // 859 // We parse an id-expression that refers to a class template or template 860 // alias. The grammar we parse is: 861 // 862 // nested-name-specifier[opt] template[opt] identifier 863 // 864 // followed by a token that terminates a template argument, such as ',', 865 // '>', or (in some cases) '>>'. 866 CXXScopeSpec SS; // nested-name-specifier, if present 867 ParseOptionalCXXScopeSpecifier(SS, /*ObjectType=*/0, 868 /*EnteringContext=*/false); 869 870 if (SS.isSet() && Tok.is(tok::kw_template)) { 871 // Parse the optional 'template' keyword following the 872 // nested-name-specifier. 873 SourceLocation TemplateLoc = ConsumeToken(); 874 875 if (Tok.is(tok::identifier)) { 876 // We appear to have a dependent template name. 877 UnqualifiedId Name; 878 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 879 ConsumeToken(); // the identifier 880 881 // If the next token signals the end of a template argument, 882 // then we have a dependent template name that could be a template 883 // template argument. 884 if (isEndOfTemplateArgument(Tok)) { 885 TemplateTy Template 886 = Actions.ActOnDependentTemplateName(TemplateLoc, SS, Name, 887 /*ObjectType=*/0, 888 /*EnteringContext=*/false); 889 if (Template.get()) 890 return ParsedTemplateArgument(SS, Template, Name.StartLocation); 891 } 892 } 893 } else if (Tok.is(tok::identifier)) { 894 // We may have a (non-dependent) template name. 895 TemplateTy Template; 896 UnqualifiedId Name; 897 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 898 ConsumeToken(); // the identifier 899 900 if (isEndOfTemplateArgument(Tok)) { 901 TemplateNameKind TNK = Actions.isTemplateName(CurScope, SS, Name, 902 /*ObjectType=*/0, 903 /*EnteringContext=*/false, 904 Template); 905 if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) { 906 // We have an id-expression that refers to a class template or 907 // (C++0x) template alias. 908 return ParsedTemplateArgument(SS, Template, Name.StartLocation); 909 } 910 } 911 } 912 913 // We don't have a template template argument. 914 return ParsedTemplateArgument(); 915} 916 917/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). 918/// 919/// template-argument: [C++ 14.2] 920/// constant-expression 921/// type-id 922/// id-expression 923ParsedTemplateArgument Parser::ParseTemplateArgument() { 924 // C++ [temp.arg]p2: 925 // In a template-argument, an ambiguity between a type-id and an 926 // expression is resolved to a type-id, regardless of the form of 927 // the corresponding template-parameter. 928 // 929 // Therefore, we initially try to parse a type-id. 930 if (isCXXTypeId(TypeIdAsTemplateArgument)) { 931 SourceLocation Loc = Tok.getLocation(); 932 TypeResult TypeArg = ParseTypeName(); 933 if (TypeArg.isInvalid()) 934 return ParsedTemplateArgument(); 935 936 return ParsedTemplateArgument(ParsedTemplateArgument::Type, TypeArg.get(), 937 Loc); 938 } 939 940 // Try to parse a template template argument. 941 { 942 TentativeParsingAction TPA(*this); 943 944 ParsedTemplateArgument TemplateTemplateArgument 945 = ParseTemplateTemplateArgument(); 946 if (!TemplateTemplateArgument.isInvalid()) { 947 TPA.Commit(); 948 return TemplateTemplateArgument; 949 } 950 951 // Revert this tentative parse to parse a non-type template argument. 952 TPA.Revert(); 953 } 954 955 // Parse a non-type template argument. 956 SourceLocation Loc = Tok.getLocation(); 957 OwningExprResult ExprArg = ParseConstantExpression(); 958 if (ExprArg.isInvalid() || !ExprArg.get()) 959 return ParsedTemplateArgument(); 960 961 return ParsedTemplateArgument(ParsedTemplateArgument::NonType, 962 ExprArg.release(), Loc); 963} 964 965/// ParseTemplateArgumentList - Parse a C++ template-argument-list 966/// (C++ [temp.names]). Returns true if there was an error. 967/// 968/// template-argument-list: [C++ 14.2] 969/// template-argument 970/// template-argument-list ',' template-argument 971bool 972Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) { 973 while (true) { 974 ParsedTemplateArgument Arg = ParseTemplateArgument(); 975 if (Arg.isInvalid()) { 976 SkipUntil(tok::comma, tok::greater, true, true); 977 return true; 978 } 979 980 // Save this template argument. 981 TemplateArgs.push_back(Arg); 982 983 // If the next token is a comma, consume it and keep reading 984 // arguments. 985 if (Tok.isNot(tok::comma)) break; 986 987 // Consume the comma. 988 ConsumeToken(); 989 } 990 991 return Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater); 992} 993 994/// \brief Parse a C++ explicit template instantiation 995/// (C++ [temp.explicit]). 996/// 997/// explicit-instantiation: 998/// 'extern' [opt] 'template' declaration 999/// 1000/// Note that the 'extern' is a GNU extension and C++0x feature. 1001Parser::DeclPtrTy 1002Parser::ParseExplicitInstantiation(SourceLocation ExternLoc, 1003 SourceLocation TemplateLoc, 1004 SourceLocation &DeclEnd) { 1005 return ParseSingleDeclarationAfterTemplate(Declarator::FileContext, 1006 ParsedTemplateInfo(ExternLoc, 1007 TemplateLoc), 1008 DeclEnd, AS_none); 1009} 1010