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 "RAIIObjectsForParser.h" 16 #include "clang/AST/ASTConsumer.h" 17 #include "clang/AST/DeclTemplate.h" 18 #include "clang/Parse/ParseDiagnostic.h" 19 #include "clang/Sema/DeclSpec.h" 20 #include "clang/Sema/ParsedTemplate.h" 21 #include "clang/Sema/Scope.h" 22 using namespace clang; 23 24 /// \brief Parse a template declaration, explicit instantiation, or 25 /// explicit specialization. 26 Decl * 27 Parser::ParseDeclarationStartingWithTemplate(unsigned Context, 28 SourceLocation &DeclEnd, 29 AccessSpecifier AS, 30 AttributeList *AccessAttrs) { 31 ObjCDeclContextSwitch ObjCDC(*this); 32 33 if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) { 34 return ParseExplicitInstantiation(Context, 35 SourceLocation(), ConsumeToken(), 36 DeclEnd, AS); 37 } 38 return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS, 39 AccessAttrs); 40 } 41 42 43 44 /// \brief Parse a template declaration or an explicit specialization. 45 /// 46 /// Template declarations include one or more template parameter lists 47 /// and either the function or class template declaration. Explicit 48 /// specializations contain one or more 'template < >' prefixes 49 /// followed by a (possibly templated) declaration. Since the 50 /// syntactic form of both features is nearly identical, we parse all 51 /// of the template headers together and let semantic analysis sort 52 /// the declarations from the explicit specializations. 53 /// 54 /// template-declaration: [C++ temp] 55 /// 'export'[opt] 'template' '<' template-parameter-list '>' declaration 56 /// 57 /// explicit-specialization: [ C++ temp.expl.spec] 58 /// 'template' '<' '>' declaration 59 Decl * 60 Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context, 61 SourceLocation &DeclEnd, 62 AccessSpecifier AS, 63 AttributeList *AccessAttrs) { 64 assert((Tok.is(tok::kw_export) || Tok.is(tok::kw_template)) && 65 "Token does not start a template declaration."); 66 67 // Enter template-parameter scope. 68 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 69 70 // Tell the action that names should be checked in the context of 71 // the declaration to come. 72 ParsingDeclRAIIObject 73 ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent); 74 75 // Parse multiple levels of template headers within this template 76 // parameter scope, e.g., 77 // 78 // template<typename T> 79 // template<typename U> 80 // class A<T>::B { ... }; 81 // 82 // We parse multiple levels non-recursively so that we can build a 83 // single data structure containing all of the template parameter 84 // lists to easily differentiate between the case above and: 85 // 86 // template<typename T> 87 // class A { 88 // template<typename U> class B; 89 // }; 90 // 91 // In the first case, the action for declaring A<T>::B receives 92 // both template parameter lists. In the second case, the action for 93 // defining A<T>::B receives just the inner template parameter list 94 // (and retrieves the outer template parameter list from its 95 // context). 96 bool isSpecialization = true; 97 bool LastParamListWasEmpty = false; 98 TemplateParameterLists ParamLists; 99 TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth); 100 101 do { 102 // Consume the 'export', if any. 103 SourceLocation ExportLoc; 104 TryConsumeToken(tok::kw_export, ExportLoc); 105 106 // Consume the 'template', which should be here. 107 SourceLocation TemplateLoc; 108 if (!TryConsumeToken(tok::kw_template, TemplateLoc)) { 109 Diag(Tok.getLocation(), diag::err_expected_template); 110 return nullptr; 111 } 112 113 // Parse the '<' template-parameter-list '>' 114 SourceLocation LAngleLoc, RAngleLoc; 115 SmallVector<Decl*, 4> TemplateParams; 116 if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(), 117 TemplateParams, LAngleLoc, RAngleLoc)) { 118 // Skip until the semi-colon or a }. 119 SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch); 120 TryConsumeToken(tok::semi); 121 return nullptr; 122 } 123 124 ParamLists.push_back( 125 Actions.ActOnTemplateParameterList(CurTemplateDepthTracker.getDepth(), 126 ExportLoc, 127 TemplateLoc, LAngleLoc, 128 TemplateParams.data(), 129 TemplateParams.size(), RAngleLoc)); 130 131 if (!TemplateParams.empty()) { 132 isSpecialization = false; 133 ++CurTemplateDepthTracker; 134 } else { 135 LastParamListWasEmpty = true; 136 } 137 } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template)); 138 139 // Parse the actual template declaration. 140 return ParseSingleDeclarationAfterTemplate(Context, 141 ParsedTemplateInfo(&ParamLists, 142 isSpecialization, 143 LastParamListWasEmpty), 144 ParsingTemplateParams, 145 DeclEnd, AS, AccessAttrs); 146 } 147 148 /// \brief Parse a single declaration that declares a template, 149 /// template specialization, or explicit instantiation of a template. 150 /// 151 /// \param DeclEnd will receive the source location of the last token 152 /// within this declaration. 153 /// 154 /// \param AS the access specifier associated with this 155 /// declaration. Will be AS_none for namespace-scope declarations. 156 /// 157 /// \returns the new declaration. 158 Decl * 159 Parser::ParseSingleDeclarationAfterTemplate( 160 unsigned Context, 161 const ParsedTemplateInfo &TemplateInfo, 162 ParsingDeclRAIIObject &DiagsFromTParams, 163 SourceLocation &DeclEnd, 164 AccessSpecifier AS, 165 AttributeList *AccessAttrs) { 166 assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate && 167 "Template information required"); 168 169 if (Context == Declarator::MemberContext) { 170 // We are parsing a member template. 171 ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo, 172 &DiagsFromTParams); 173 return nullptr; 174 } 175 176 ParsedAttributesWithRange prefixAttrs(AttrFactory); 177 MaybeParseCXX11Attributes(prefixAttrs); 178 179 if (Tok.is(tok::kw_using)) 180 return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd, 181 prefixAttrs); 182 183 // Parse the declaration specifiers, stealing any diagnostics from 184 // the template parameters. 185 ParsingDeclSpec DS(*this, &DiagsFromTParams); 186 187 ParseDeclarationSpecifiers(DS, TemplateInfo, AS, 188 getDeclSpecContextFromDeclaratorContext(Context)); 189 190 if (Tok.is(tok::semi)) { 191 ProhibitAttributes(prefixAttrs); 192 DeclEnd = ConsumeToken(); 193 Decl *Decl = Actions.ParsedFreeStandingDeclSpec( 194 getCurScope(), AS, DS, 195 TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams 196 : MultiTemplateParamsArg(), 197 TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation); 198 DS.complete(Decl); 199 return Decl; 200 } 201 202 // Move the attributes from the prefix into the DS. 203 if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) 204 ProhibitAttributes(prefixAttrs); 205 else 206 DS.takeAttributesFrom(prefixAttrs); 207 208 // Parse the declarator. 209 ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context); 210 ParseDeclarator(DeclaratorInfo); 211 // Error parsing the declarator? 212 if (!DeclaratorInfo.hasName()) { 213 // If so, skip until the semi-colon or a }. 214 SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch); 215 if (Tok.is(tok::semi)) 216 ConsumeToken(); 217 return nullptr; 218 } 219 220 LateParsedAttrList LateParsedAttrs(true); 221 if (DeclaratorInfo.isFunctionDeclarator()) 222 MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs); 223 224 if (DeclaratorInfo.isFunctionDeclarator() && 225 isStartOfFunctionDefinition(DeclaratorInfo)) { 226 if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) { 227 // Recover by ignoring the 'typedef'. This was probably supposed to be 228 // the 'typename' keyword, which we should have already suggested adding 229 // if it's appropriate. 230 Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef) 231 << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc()); 232 DS.ClearStorageClassSpecs(); 233 } 234 235 if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) { 236 if (DeclaratorInfo.getName().getKind() != UnqualifiedId::IK_TemplateId) { 237 // If the declarator-id is not a template-id, issue a diagnostic and 238 // recover by ignoring the 'template' keyword. 239 Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0; 240 return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(), 241 &LateParsedAttrs); 242 } else { 243 SourceLocation LAngleLoc 244 = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc); 245 Diag(DeclaratorInfo.getIdentifierLoc(), 246 diag::err_explicit_instantiation_with_definition) 247 << SourceRange(TemplateInfo.TemplateLoc) 248 << FixItHint::CreateInsertion(LAngleLoc, "<>"); 249 250 // Recover as if it were an explicit specialization. 251 TemplateParameterLists FakedParamLists; 252 FakedParamLists.push_back(Actions.ActOnTemplateParameterList( 253 0, SourceLocation(), TemplateInfo.TemplateLoc, LAngleLoc, nullptr, 254 0, LAngleLoc)); 255 256 return ParseFunctionDefinition( 257 DeclaratorInfo, ParsedTemplateInfo(&FakedParamLists, 258 /*isSpecialization=*/true, 259 /*LastParamListWasEmpty=*/true), 260 &LateParsedAttrs); 261 } 262 } 263 return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo, 264 &LateParsedAttrs); 265 } 266 267 // Parse this declaration. 268 Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo, 269 TemplateInfo); 270 271 if (Tok.is(tok::comma)) { 272 Diag(Tok, diag::err_multiple_template_declarators) 273 << (int)TemplateInfo.Kind; 274 SkipUntil(tok::semi); 275 return ThisDecl; 276 } 277 278 // Eat the semi colon after the declaration. 279 ExpectAndConsumeSemi(diag::err_expected_semi_declaration); 280 if (LateParsedAttrs.size() > 0) 281 ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false); 282 DeclaratorInfo.complete(ThisDecl); 283 return ThisDecl; 284 } 285 286 /// ParseTemplateParameters - Parses a template-parameter-list enclosed in 287 /// angle brackets. Depth is the depth of this template-parameter-list, which 288 /// is the number of template headers directly enclosing this template header. 289 /// TemplateParams is the current list of template parameters we're building. 290 /// The template parameter we parse will be added to this list. LAngleLoc and 291 /// RAngleLoc will receive the positions of the '<' and '>', respectively, 292 /// that enclose this template parameter list. 293 /// 294 /// \returns true if an error occurred, false otherwise. 295 bool Parser::ParseTemplateParameters(unsigned Depth, 296 SmallVectorImpl<Decl*> &TemplateParams, 297 SourceLocation &LAngleLoc, 298 SourceLocation &RAngleLoc) { 299 // Get the template parameter list. 300 if (!TryConsumeToken(tok::less, LAngleLoc)) { 301 Diag(Tok.getLocation(), diag::err_expected_less_after) << "template"; 302 return true; 303 } 304 305 // Try to parse the template parameter list. 306 bool Failed = false; 307 if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater)) 308 Failed = ParseTemplateParameterList(Depth, TemplateParams); 309 310 if (Tok.is(tok::greatergreater)) { 311 // No diagnostic required here: a template-parameter-list can only be 312 // followed by a declaration or, for a template template parameter, the 313 // 'class' keyword. Therefore, the second '>' will be diagnosed later. 314 // This matters for elegant diagnosis of: 315 // template<template<typename>> struct S; 316 Tok.setKind(tok::greater); 317 RAngleLoc = Tok.getLocation(); 318 Tok.setLocation(Tok.getLocation().getLocWithOffset(1)); 319 } else if (!TryConsumeToken(tok::greater, RAngleLoc) && Failed) { 320 Diag(Tok.getLocation(), diag::err_expected) << tok::greater; 321 return true; 322 } 323 return false; 324 } 325 326 /// ParseTemplateParameterList - Parse a template parameter list. If 327 /// the parsing fails badly (i.e., closing bracket was left out), this 328 /// will try to put the token stream in a reasonable position (closing 329 /// a statement, etc.) and return false. 330 /// 331 /// template-parameter-list: [C++ temp] 332 /// template-parameter 333 /// template-parameter-list ',' template-parameter 334 bool 335 Parser::ParseTemplateParameterList(unsigned Depth, 336 SmallVectorImpl<Decl*> &TemplateParams) { 337 while (1) { 338 if (Decl *TmpParam 339 = ParseTemplateParameter(Depth, TemplateParams.size())) { 340 TemplateParams.push_back(TmpParam); 341 } else { 342 // If we failed to parse a template parameter, skip until we find 343 // a comma or closing brace. 344 SkipUntil(tok::comma, tok::greater, tok::greatergreater, 345 StopAtSemi | StopBeforeMatch); 346 } 347 348 // Did we find a comma or the end of the template parameter list? 349 if (Tok.is(tok::comma)) { 350 ConsumeToken(); 351 } else if (Tok.is(tok::greater) || Tok.is(tok::greatergreater)) { 352 // Don't consume this... that's done by template parser. 353 break; 354 } else { 355 // Somebody probably forgot to close the template. Skip ahead and 356 // try to get out of the expression. This error is currently 357 // subsumed by whatever goes on in ParseTemplateParameter. 358 Diag(Tok.getLocation(), diag::err_expected_comma_greater); 359 SkipUntil(tok::comma, tok::greater, tok::greatergreater, 360 StopAtSemi | StopBeforeMatch); 361 return false; 362 } 363 } 364 return true; 365 } 366 367 /// \brief Determine whether the parser is at the start of a template 368 /// type parameter. 369 bool Parser::isStartOfTemplateTypeParameter() { 370 if (Tok.is(tok::kw_class)) { 371 // "class" may be the start of an elaborated-type-specifier or a 372 // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter. 373 switch (NextToken().getKind()) { 374 case tok::equal: 375 case tok::comma: 376 case tok::greater: 377 case tok::greatergreater: 378 case tok::ellipsis: 379 return true; 380 381 case tok::identifier: 382 // This may be either a type-parameter or an elaborated-type-specifier. 383 // We have to look further. 384 break; 385 386 default: 387 return false; 388 } 389 390 switch (GetLookAheadToken(2).getKind()) { 391 case tok::equal: 392 case tok::comma: 393 case tok::greater: 394 case tok::greatergreater: 395 return true; 396 397 default: 398 return false; 399 } 400 } 401 402 if (Tok.isNot(tok::kw_typename)) 403 return false; 404 405 // C++ [temp.param]p2: 406 // There is no semantic difference between class and typename in a 407 // template-parameter. typename followed by an unqualified-id 408 // names a template type parameter. typename followed by a 409 // qualified-id denotes the type in a non-type 410 // parameter-declaration. 411 Token Next = NextToken(); 412 413 // If we have an identifier, skip over it. 414 if (Next.getKind() == tok::identifier) 415 Next = GetLookAheadToken(2); 416 417 switch (Next.getKind()) { 418 case tok::equal: 419 case tok::comma: 420 case tok::greater: 421 case tok::greatergreater: 422 case tok::ellipsis: 423 return true; 424 425 default: 426 return false; 427 } 428 } 429 430 /// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]). 431 /// 432 /// template-parameter: [C++ temp.param] 433 /// type-parameter 434 /// parameter-declaration 435 /// 436 /// type-parameter: (see below) 437 /// 'class' ...[opt] identifier[opt] 438 /// 'class' identifier[opt] '=' type-id 439 /// 'typename' ...[opt] identifier[opt] 440 /// 'typename' identifier[opt] '=' type-id 441 /// 'template' '<' template-parameter-list '>' 442 /// 'class' ...[opt] identifier[opt] 443 /// 'template' '<' template-parameter-list '>' 'class' identifier[opt] 444 /// = id-expression 445 Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { 446 if (isStartOfTemplateTypeParameter()) 447 return ParseTypeParameter(Depth, Position); 448 449 if (Tok.is(tok::kw_template)) 450 return ParseTemplateTemplateParameter(Depth, Position); 451 452 // If it's none of the above, then it must be a parameter declaration. 453 // NOTE: This will pick up errors in the closure of the template parameter 454 // list (e.g., template < ; Check here to implement >> style closures. 455 return ParseNonTypeTemplateParameter(Depth, Position); 456 } 457 458 /// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]). 459 /// Other kinds of template parameters are parsed in 460 /// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter. 461 /// 462 /// type-parameter: [C++ temp.param] 463 /// 'class' ...[opt][C++0x] identifier[opt] 464 /// 'class' identifier[opt] '=' type-id 465 /// 'typename' ...[opt][C++0x] identifier[opt] 466 /// 'typename' identifier[opt] '=' type-id 467 Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) { 468 assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) && 469 "A type-parameter starts with 'class' or 'typename'"); 470 471 // Consume the 'class' or 'typename' keyword. 472 bool TypenameKeyword = Tok.is(tok::kw_typename); 473 SourceLocation KeyLoc = ConsumeToken(); 474 475 // Grab the ellipsis (if given). 476 SourceLocation EllipsisLoc; 477 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) { 478 Diag(EllipsisLoc, 479 getLangOpts().CPlusPlus11 480 ? diag::warn_cxx98_compat_variadic_templates 481 : diag::ext_variadic_templates); 482 } 483 484 // Grab the template parameter name (if given) 485 SourceLocation NameLoc; 486 IdentifierInfo *ParamName = nullptr; 487 if (Tok.is(tok::identifier)) { 488 ParamName = Tok.getIdentifierInfo(); 489 NameLoc = ConsumeToken(); 490 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || 491 Tok.is(tok::greater) || Tok.is(tok::greatergreater)) { 492 // Unnamed template parameter. Don't have to do anything here, just 493 // don't consume this token. 494 } else { 495 Diag(Tok.getLocation(), diag::err_expected) << tok::identifier; 496 return nullptr; 497 } 498 499 // Recover from misplaced ellipsis. 500 bool AlreadyHasEllipsis = EllipsisLoc.isValid(); 501 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) 502 DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true); 503 504 // Grab a default argument (if available). 505 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 506 // we introduce the type parameter into the local scope. 507 SourceLocation EqualLoc; 508 ParsedType DefaultArg; 509 if (TryConsumeToken(tok::equal, EqualLoc)) 510 DefaultArg = ParseTypeName(/*Range=*/nullptr, 511 Declarator::TemplateTypeArgContext).get(); 512 513 return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, EllipsisLoc, 514 KeyLoc, ParamName, NameLoc, Depth, Position, 515 EqualLoc, DefaultArg); 516 } 517 518 /// ParseTemplateTemplateParameter - Handle the parsing of template 519 /// template parameters. 520 /// 521 /// type-parameter: [C++ temp.param] 522 /// 'template' '<' template-parameter-list '>' type-parameter-key 523 /// ...[opt] identifier[opt] 524 /// 'template' '<' template-parameter-list '>' type-parameter-key 525 /// identifier[opt] = id-expression 526 /// type-parameter-key: 527 /// 'class' 528 /// 'typename' [C++1z] 529 Decl * 530 Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { 531 assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); 532 533 // Handle the template <...> part. 534 SourceLocation TemplateLoc = ConsumeToken(); 535 SmallVector<Decl*,8> TemplateParams; 536 SourceLocation LAngleLoc, RAngleLoc; 537 { 538 ParseScope TemplateParmScope(this, Scope::TemplateParamScope); 539 if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, 540 RAngleLoc)) { 541 return nullptr; 542 } 543 } 544 545 // Provide an ExtWarn if the C++1z feature of using 'typename' here is used. 546 // Generate a meaningful error if the user forgot to put class before the 547 // identifier, comma, or greater. Provide a fixit if the identifier, comma, 548 // or greater appear immediately or after 'struct'. In the latter case, 549 // replace the keyword with 'class'. 550 if (!TryConsumeToken(tok::kw_class)) { 551 bool Replace = Tok.is(tok::kw_typename) || Tok.is(tok::kw_struct); 552 const Token &Next = Tok.is(tok::kw_struct) ? NextToken() : Tok; 553 if (Tok.is(tok::kw_typename)) { 554 Diag(Tok.getLocation(), 555 getLangOpts().CPlusPlus1z 556 ? diag::warn_cxx1y_compat_template_template_param_typename 557 : diag::ext_template_template_param_typename) 558 << (!getLangOpts().CPlusPlus1z 559 ? FixItHint::CreateReplacement(Tok.getLocation(), "class") 560 : FixItHint()); 561 } else if (Next.is(tok::identifier) || Next.is(tok::comma) || 562 Next.is(tok::greater) || Next.is(tok::greatergreater) || 563 Next.is(tok::ellipsis)) { 564 Diag(Tok.getLocation(), diag::err_class_on_template_template_param) 565 << (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class") 566 : FixItHint::CreateInsertion(Tok.getLocation(), "class ")); 567 } else 568 Diag(Tok.getLocation(), diag::err_class_on_template_template_param); 569 570 if (Replace) 571 ConsumeToken(); 572 } 573 574 // Parse the ellipsis, if given. 575 SourceLocation EllipsisLoc; 576 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) 577 Diag(EllipsisLoc, 578 getLangOpts().CPlusPlus11 579 ? diag::warn_cxx98_compat_variadic_templates 580 : diag::ext_variadic_templates); 581 582 // Get the identifier, if given. 583 SourceLocation NameLoc; 584 IdentifierInfo *ParamName = nullptr; 585 if (Tok.is(tok::identifier)) { 586 ParamName = Tok.getIdentifierInfo(); 587 NameLoc = ConsumeToken(); 588 } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || 589 Tok.is(tok::greater) || Tok.is(tok::greatergreater)) { 590 // Unnamed template parameter. Don't have to do anything here, just 591 // don't consume this token. 592 } else { 593 Diag(Tok.getLocation(), diag::err_expected) << tok::identifier; 594 return nullptr; 595 } 596 597 // Recover from misplaced ellipsis. 598 bool AlreadyHasEllipsis = EllipsisLoc.isValid(); 599 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) 600 DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true); 601 602 TemplateParameterList *ParamList = 603 Actions.ActOnTemplateParameterList(Depth, SourceLocation(), 604 TemplateLoc, LAngleLoc, 605 TemplateParams.data(), 606 TemplateParams.size(), 607 RAngleLoc); 608 609 // Grab a default argument (if available). 610 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 611 // we introduce the template parameter into the local scope. 612 SourceLocation EqualLoc; 613 ParsedTemplateArgument DefaultArg; 614 if (TryConsumeToken(tok::equal, EqualLoc)) { 615 DefaultArg = ParseTemplateTemplateArgument(); 616 if (DefaultArg.isInvalid()) { 617 Diag(Tok.getLocation(), 618 diag::err_default_template_template_parameter_not_template); 619 SkipUntil(tok::comma, tok::greater, tok::greatergreater, 620 StopAtSemi | StopBeforeMatch); 621 } 622 } 623 624 return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc, 625 ParamList, EllipsisLoc, 626 ParamName, NameLoc, Depth, 627 Position, EqualLoc, DefaultArg); 628 } 629 630 /// ParseNonTypeTemplateParameter - Handle the parsing of non-type 631 /// template parameters (e.g., in "template<int Size> class array;"). 632 /// 633 /// template-parameter: 634 /// ... 635 /// parameter-declaration 636 Decl * 637 Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { 638 // Parse the declaration-specifiers (i.e., the type). 639 // FIXME: The type should probably be restricted in some way... Not all 640 // declarators (parts of declarators?) are accepted for parameters. 641 DeclSpec DS(AttrFactory); 642 ParseDeclarationSpecifiers(DS); 643 644 // Parse this as a typename. 645 Declarator ParamDecl(DS, Declarator::TemplateParamContext); 646 ParseDeclarator(ParamDecl); 647 if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) { 648 Diag(Tok.getLocation(), diag::err_expected_template_parameter); 649 return nullptr; 650 } 651 652 // Recover from misplaced ellipsis. 653 SourceLocation EllipsisLoc; 654 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) 655 DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, ParamDecl); 656 657 // If there is a default value, parse it. 658 // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before 659 // we introduce the template parameter into the local scope. 660 SourceLocation EqualLoc; 661 ExprResult DefaultArg; 662 if (TryConsumeToken(tok::equal, EqualLoc)) { 663 // C++ [temp.param]p15: 664 // When parsing a default template-argument for a non-type 665 // template-parameter, the first non-nested > is taken as the 666 // end of the template-parameter-list rather than a greater-than 667 // operator. 668 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 669 EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated); 670 671 DefaultArg = ParseAssignmentExpression(); 672 if (DefaultArg.isInvalid()) 673 SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch); 674 } 675 676 // Create the parameter. 677 return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl, 678 Depth, Position, EqualLoc, 679 DefaultArg.get()); 680 } 681 682 void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc, 683 SourceLocation CorrectLoc, 684 bool AlreadyHasEllipsis, 685 bool IdentifierHasName) { 686 FixItHint Insertion; 687 if (!AlreadyHasEllipsis) 688 Insertion = FixItHint::CreateInsertion(CorrectLoc, "..."); 689 Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration) 690 << FixItHint::CreateRemoval(EllipsisLoc) << Insertion 691 << !IdentifierHasName; 692 } 693 694 void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc, 695 Declarator &D) { 696 assert(EllipsisLoc.isValid()); 697 bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid(); 698 if (!AlreadyHasEllipsis) 699 D.setEllipsisLoc(EllipsisLoc); 700 DiagnoseMisplacedEllipsis(EllipsisLoc, D.getIdentifierLoc(), 701 AlreadyHasEllipsis, D.hasName()); 702 } 703 704 /// \brief Parses a '>' at the end of a template list. 705 /// 706 /// If this function encounters '>>', '>>>', '>=', or '>>=', it tries 707 /// to determine if these tokens were supposed to be a '>' followed by 708 /// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary. 709 /// 710 /// \param RAngleLoc the location of the consumed '>'. 711 /// 712 /// \param ConsumeLastToken if true, the '>' is not consumed. 713 /// 714 /// \returns true, if current token does not start with '>', false otherwise. 715 bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc, 716 bool ConsumeLastToken) { 717 // What will be left once we've consumed the '>'. 718 tok::TokenKind RemainingToken; 719 const char *ReplacementStr = "> >"; 720 721 switch (Tok.getKind()) { 722 default: 723 Diag(Tok.getLocation(), diag::err_expected) << tok::greater; 724 return true; 725 726 case tok::greater: 727 // Determine the location of the '>' token. Only consume this token 728 // if the caller asked us to. 729 RAngleLoc = Tok.getLocation(); 730 if (ConsumeLastToken) 731 ConsumeToken(); 732 return false; 733 734 case tok::greatergreater: 735 RemainingToken = tok::greater; 736 break; 737 738 case tok::greatergreatergreater: 739 RemainingToken = tok::greatergreater; 740 break; 741 742 case tok::greaterequal: 743 RemainingToken = tok::equal; 744 ReplacementStr = "> ="; 745 break; 746 747 case tok::greatergreaterequal: 748 RemainingToken = tok::greaterequal; 749 break; 750 } 751 752 // This template-id is terminated by a token which starts with a '>'. Outside 753 // C++11, this is now error recovery, and in C++11, this is error recovery if 754 // the token isn't '>>' or '>>>'. 755 // '>>>' is for CUDA, where this sequence of characters is parsed into 756 // tok::greatergreatergreater, rather than two separate tokens. 757 758 RAngleLoc = Tok.getLocation(); 759 760 // The source range of the '>>' or '>=' at the start of the token. 761 CharSourceRange ReplacementRange = 762 CharSourceRange::getCharRange(RAngleLoc, 763 Lexer::AdvanceToTokenCharacter(RAngleLoc, 2, PP.getSourceManager(), 764 getLangOpts())); 765 766 // A hint to put a space between the '>>'s. In order to make the hint as 767 // clear as possible, we include the characters either side of the space in 768 // the replacement, rather than just inserting a space at SecondCharLoc. 769 FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange, 770 ReplacementStr); 771 772 // A hint to put another space after the token, if it would otherwise be 773 // lexed differently. 774 FixItHint Hint2; 775 Token Next = NextToken(); 776 if ((RemainingToken == tok::greater || 777 RemainingToken == tok::greatergreater) && 778 (Next.is(tok::greater) || Next.is(tok::greatergreater) || 779 Next.is(tok::greatergreatergreater) || Next.is(tok::equal) || 780 Next.is(tok::greaterequal) || Next.is(tok::greatergreaterequal) || 781 Next.is(tok::equalequal)) && 782 areTokensAdjacent(Tok, Next)) 783 Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " "); 784 785 unsigned DiagId = diag::err_two_right_angle_brackets_need_space; 786 if (getLangOpts().CPlusPlus11 && 787 (Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater))) 788 DiagId = diag::warn_cxx98_compat_two_right_angle_brackets; 789 else if (Tok.is(tok::greaterequal)) 790 DiagId = diag::err_right_angle_bracket_equal_needs_space; 791 Diag(Tok.getLocation(), DiagId) << Hint1 << Hint2; 792 793 // Strip the initial '>' from the token. 794 if (RemainingToken == tok::equal && Next.is(tok::equal) && 795 areTokensAdjacent(Tok, Next)) { 796 // Join two adjacent '=' tokens into one, for cases like: 797 // void (*p)() = f<int>; 798 // return f<int>==p; 799 ConsumeToken(); 800 Tok.setKind(tok::equalequal); 801 Tok.setLength(Tok.getLength() + 1); 802 } else { 803 Tok.setKind(RemainingToken); 804 Tok.setLength(Tok.getLength() - 1); 805 } 806 Tok.setLocation(Lexer::AdvanceToTokenCharacter(RAngleLoc, 1, 807 PP.getSourceManager(), 808 getLangOpts())); 809 810 if (!ConsumeLastToken) { 811 // Since we're not supposed to consume the '>' token, we need to push 812 // this token and revert the current token back to the '>'. 813 PP.EnterToken(Tok); 814 Tok.setKind(tok::greater); 815 Tok.setLength(1); 816 Tok.setLocation(RAngleLoc); 817 } 818 return false; 819 } 820 821 822 /// \brief Parses a template-id that after the template name has 823 /// already been parsed. 824 /// 825 /// This routine takes care of parsing the enclosed template argument 826 /// list ('<' template-parameter-list [opt] '>') and placing the 827 /// results into a form that can be transferred to semantic analysis. 828 /// 829 /// \param Template the template declaration produced by isTemplateName 830 /// 831 /// \param TemplateNameLoc the source location of the template name 832 /// 833 /// \param SS if non-NULL, the nested-name-specifier preceding the 834 /// template name. 835 /// 836 /// \param ConsumeLastToken if true, then we will consume the last 837 /// token that forms the template-id. Otherwise, we will leave the 838 /// last token in the stream (e.g., so that it can be replaced with an 839 /// annotation token). 840 bool 841 Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template, 842 SourceLocation TemplateNameLoc, 843 const CXXScopeSpec &SS, 844 bool ConsumeLastToken, 845 SourceLocation &LAngleLoc, 846 TemplateArgList &TemplateArgs, 847 SourceLocation &RAngleLoc) { 848 assert(Tok.is(tok::less) && "Must have already parsed the template-name"); 849 850 // Consume the '<'. 851 LAngleLoc = ConsumeToken(); 852 853 // Parse the optional template-argument-list. 854 bool Invalid = false; 855 { 856 GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); 857 if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) 858 Invalid = ParseTemplateArgumentList(TemplateArgs); 859 860 if (Invalid) { 861 // Try to find the closing '>'. 862 if (ConsumeLastToken) 863 SkipUntil(tok::greater, StopAtSemi); 864 else 865 SkipUntil(tok::greater, StopAtSemi | StopBeforeMatch); 866 return true; 867 } 868 } 869 870 return ParseGreaterThanInTemplateList(RAngleLoc, ConsumeLastToken); 871 } 872 873 /// \brief Replace the tokens that form a simple-template-id with an 874 /// annotation token containing the complete template-id. 875 /// 876 /// The first token in the stream must be the name of a template that 877 /// is followed by a '<'. This routine will parse the complete 878 /// simple-template-id and replace the tokens with a single annotation 879 /// token with one of two different kinds: if the template-id names a 880 /// type (and \p AllowTypeAnnotation is true), the annotation token is 881 /// a type annotation that includes the optional nested-name-specifier 882 /// (\p SS). Otherwise, the annotation token is a template-id 883 /// annotation that does not include the optional 884 /// nested-name-specifier. 885 /// 886 /// \param Template the declaration of the template named by the first 887 /// token (an identifier), as returned from \c Action::isTemplateName(). 888 /// 889 /// \param TNK the kind of template that \p Template 890 /// refers to, as returned from \c Action::isTemplateName(). 891 /// 892 /// \param SS if non-NULL, the nested-name-specifier that precedes 893 /// this template name. 894 /// 895 /// \param TemplateKWLoc if valid, specifies that this template-id 896 /// annotation was preceded by the 'template' keyword and gives the 897 /// location of that keyword. If invalid (the default), then this 898 /// template-id was not preceded by a 'template' keyword. 899 /// 900 /// \param AllowTypeAnnotation if true (the default), then a 901 /// simple-template-id that refers to a class template, template 902 /// template parameter, or other template that produces a type will be 903 /// replaced with a type annotation token. Otherwise, the 904 /// simple-template-id is always replaced with a template-id 905 /// annotation token. 906 /// 907 /// If an unrecoverable parse error occurs and no annotation token can be 908 /// formed, this function returns true. 909 /// 910 bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK, 911 CXXScopeSpec &SS, 912 SourceLocation TemplateKWLoc, 913 UnqualifiedId &TemplateName, 914 bool AllowTypeAnnotation) { 915 assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++"); 916 assert(Template && Tok.is(tok::less) && 917 "Parser isn't at the beginning of a template-id"); 918 919 // Consume the template-name. 920 SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin(); 921 922 // Parse the enclosed template argument list. 923 SourceLocation LAngleLoc, RAngleLoc; 924 TemplateArgList TemplateArgs; 925 bool Invalid = ParseTemplateIdAfterTemplateName(Template, 926 TemplateNameLoc, 927 SS, false, LAngleLoc, 928 TemplateArgs, 929 RAngleLoc); 930 931 if (Invalid) { 932 // If we failed to parse the template ID but skipped ahead to a >, we're not 933 // going to be able to form a token annotation. Eat the '>' if present. 934 TryConsumeToken(tok::greater); 935 return true; 936 } 937 938 ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs); 939 940 // Build the annotation token. 941 if (TNK == TNK_Type_template && AllowTypeAnnotation) { 942 TypeResult Type 943 = Actions.ActOnTemplateIdType(SS, TemplateKWLoc, 944 Template, TemplateNameLoc, 945 LAngleLoc, TemplateArgsPtr, RAngleLoc); 946 if (Type.isInvalid()) { 947 // If we failed to parse the template ID but skipped ahead to a >, we're not 948 // going to be able to form a token annotation. Eat the '>' if present. 949 TryConsumeToken(tok::greater); 950 return true; 951 } 952 953 Tok.setKind(tok::annot_typename); 954 setTypeAnnotation(Tok, Type.get()); 955 if (SS.isNotEmpty()) 956 Tok.setLocation(SS.getBeginLoc()); 957 else if (TemplateKWLoc.isValid()) 958 Tok.setLocation(TemplateKWLoc); 959 else 960 Tok.setLocation(TemplateNameLoc); 961 } else { 962 // Build a template-id annotation token that can be processed 963 // later. 964 Tok.setKind(tok::annot_template_id); 965 TemplateIdAnnotation *TemplateId 966 = TemplateIdAnnotation::Allocate(TemplateArgs.size(), TemplateIds); 967 TemplateId->TemplateNameLoc = TemplateNameLoc; 968 if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) { 969 TemplateId->Name = TemplateName.Identifier; 970 TemplateId->Operator = OO_None; 971 } else { 972 TemplateId->Name = nullptr; 973 TemplateId->Operator = TemplateName.OperatorFunctionId.Operator; 974 } 975 TemplateId->SS = SS; 976 TemplateId->TemplateKWLoc = TemplateKWLoc; 977 TemplateId->Template = Template; 978 TemplateId->Kind = TNK; 979 TemplateId->LAngleLoc = LAngleLoc; 980 TemplateId->RAngleLoc = RAngleLoc; 981 ParsedTemplateArgument *Args = TemplateId->getTemplateArgs(); 982 for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) 983 Args[Arg] = ParsedTemplateArgument(TemplateArgs[Arg]); 984 Tok.setAnnotationValue(TemplateId); 985 if (TemplateKWLoc.isValid()) 986 Tok.setLocation(TemplateKWLoc); 987 else 988 Tok.setLocation(TemplateNameLoc); 989 } 990 991 // Common fields for the annotation token 992 Tok.setAnnotationEndLoc(RAngleLoc); 993 994 // In case the tokens were cached, have Preprocessor replace them with the 995 // annotation token. 996 PP.AnnotateCachedTokens(Tok); 997 return false; 998 } 999 1000 /// \brief Replaces a template-id annotation token with a type 1001 /// annotation token. 1002 /// 1003 /// If there was a failure when forming the type from the template-id, 1004 /// a type annotation token will still be created, but will have a 1005 /// NULL type pointer to signify an error. 1006 void Parser::AnnotateTemplateIdTokenAsType() { 1007 assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens"); 1008 1009 TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok); 1010 assert((TemplateId->Kind == TNK_Type_template || 1011 TemplateId->Kind == TNK_Dependent_template_name) && 1012 "Only works for type and dependent templates"); 1013 1014 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(), 1015 TemplateId->NumArgs); 1016 1017 TypeResult Type 1018 = Actions.ActOnTemplateIdType(TemplateId->SS, 1019 TemplateId->TemplateKWLoc, 1020 TemplateId->Template, 1021 TemplateId->TemplateNameLoc, 1022 TemplateId->LAngleLoc, 1023 TemplateArgsPtr, 1024 TemplateId->RAngleLoc); 1025 // Create the new "type" annotation token. 1026 Tok.setKind(tok::annot_typename); 1027 setTypeAnnotation(Tok, Type.isInvalid() ? ParsedType() : Type.get()); 1028 if (TemplateId->SS.isNotEmpty()) // it was a C++ qualified type name. 1029 Tok.setLocation(TemplateId->SS.getBeginLoc()); 1030 // End location stays the same 1031 1032 // Replace the template-id annotation token, and possible the scope-specifier 1033 // that precedes it, with the typename annotation token. 1034 PP.AnnotateCachedTokens(Tok); 1035 } 1036 1037 /// \brief Determine whether the given token can end a template argument. 1038 static bool isEndOfTemplateArgument(Token Tok) { 1039 return Tok.is(tok::comma) || Tok.is(tok::greater) || 1040 Tok.is(tok::greatergreater); 1041 } 1042 1043 /// \brief Parse a C++ template template argument. 1044 ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() { 1045 if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) && 1046 !Tok.is(tok::annot_cxxscope)) 1047 return ParsedTemplateArgument(); 1048 1049 // C++0x [temp.arg.template]p1: 1050 // A template-argument for a template template-parameter shall be the name 1051 // of a class template or an alias template, expressed as id-expression. 1052 // 1053 // We parse an id-expression that refers to a class template or alias 1054 // template. The grammar we parse is: 1055 // 1056 // nested-name-specifier[opt] template[opt] identifier ...[opt] 1057 // 1058 // followed by a token that terminates a template argument, such as ',', 1059 // '>', or (in some cases) '>>'. 1060 CXXScopeSpec SS; // nested-name-specifier, if present 1061 ParseOptionalCXXScopeSpecifier(SS, ParsedType(), 1062 /*EnteringContext=*/false); 1063 1064 ParsedTemplateArgument Result; 1065 SourceLocation EllipsisLoc; 1066 if (SS.isSet() && Tok.is(tok::kw_template)) { 1067 // Parse the optional 'template' keyword following the 1068 // nested-name-specifier. 1069 SourceLocation TemplateKWLoc = ConsumeToken(); 1070 1071 if (Tok.is(tok::identifier)) { 1072 // We appear to have a dependent template name. 1073 UnqualifiedId Name; 1074 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 1075 ConsumeToken(); // the identifier 1076 1077 TryConsumeToken(tok::ellipsis, EllipsisLoc); 1078 1079 // If the next token signals the end of a template argument, 1080 // then we have a dependent template name that could be a template 1081 // template argument. 1082 TemplateTy Template; 1083 if (isEndOfTemplateArgument(Tok) && 1084 Actions.ActOnDependentTemplateName(getCurScope(), 1085 SS, TemplateKWLoc, Name, 1086 /*ObjectType=*/ ParsedType(), 1087 /*EnteringContext=*/false, 1088 Template)) 1089 Result = ParsedTemplateArgument(SS, Template, Name.StartLocation); 1090 } 1091 } else if (Tok.is(tok::identifier)) { 1092 // We may have a (non-dependent) template name. 1093 TemplateTy Template; 1094 UnqualifiedId Name; 1095 Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); 1096 ConsumeToken(); // the identifier 1097 1098 TryConsumeToken(tok::ellipsis, EllipsisLoc); 1099 1100 if (isEndOfTemplateArgument(Tok)) { 1101 bool MemberOfUnknownSpecialization; 1102 TemplateNameKind TNK = Actions.isTemplateName(getCurScope(), SS, 1103 /*hasTemplateKeyword=*/false, 1104 Name, 1105 /*ObjectType=*/ ParsedType(), 1106 /*EnteringContext=*/false, 1107 Template, 1108 MemberOfUnknownSpecialization); 1109 if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) { 1110 // We have an id-expression that refers to a class template or 1111 // (C++0x) alias template. 1112 Result = ParsedTemplateArgument(SS, Template, Name.StartLocation); 1113 } 1114 } 1115 } 1116 1117 // If this is a pack expansion, build it as such. 1118 if (EllipsisLoc.isValid() && !Result.isInvalid()) 1119 Result = Actions.ActOnPackExpansion(Result, EllipsisLoc); 1120 1121 return Result; 1122 } 1123 1124 /// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). 1125 /// 1126 /// template-argument: [C++ 14.2] 1127 /// constant-expression 1128 /// type-id 1129 /// id-expression 1130 ParsedTemplateArgument Parser::ParseTemplateArgument() { 1131 // C++ [temp.arg]p2: 1132 // In a template-argument, an ambiguity between a type-id and an 1133 // expression is resolved to a type-id, regardless of the form of 1134 // the corresponding template-parameter. 1135 // 1136 // Therefore, we initially try to parse a type-id. 1137 if (isCXXTypeId(TypeIdAsTemplateArgument)) { 1138 SourceLocation Loc = Tok.getLocation(); 1139 TypeResult TypeArg = ParseTypeName(/*Range=*/nullptr, 1140 Declarator::TemplateTypeArgContext); 1141 if (TypeArg.isInvalid()) 1142 return ParsedTemplateArgument(); 1143 1144 return ParsedTemplateArgument(ParsedTemplateArgument::Type, 1145 TypeArg.get().getAsOpaquePtr(), 1146 Loc); 1147 } 1148 1149 // Try to parse a template template argument. 1150 { 1151 TentativeParsingAction TPA(*this); 1152 1153 ParsedTemplateArgument TemplateTemplateArgument 1154 = ParseTemplateTemplateArgument(); 1155 if (!TemplateTemplateArgument.isInvalid()) { 1156 TPA.Commit(); 1157 return TemplateTemplateArgument; 1158 } 1159 1160 // Revert this tentative parse to parse a non-type template argument. 1161 TPA.Revert(); 1162 } 1163 1164 // Parse a non-type template argument. 1165 SourceLocation Loc = Tok.getLocation(); 1166 ExprResult ExprArg = ParseConstantExpression(MaybeTypeCast); 1167 if (ExprArg.isInvalid() || !ExprArg.get()) 1168 return ParsedTemplateArgument(); 1169 1170 return ParsedTemplateArgument(ParsedTemplateArgument::NonType, 1171 ExprArg.get(), Loc); 1172 } 1173 1174 /// \brief Determine whether the current tokens can only be parsed as a 1175 /// template argument list (starting with the '<') and never as a '<' 1176 /// expression. 1177 bool Parser::IsTemplateArgumentList(unsigned Skip) { 1178 struct AlwaysRevertAction : TentativeParsingAction { 1179 AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { } 1180 ~AlwaysRevertAction() { Revert(); } 1181 } Tentative(*this); 1182 1183 while (Skip) { 1184 ConsumeToken(); 1185 --Skip; 1186 } 1187 1188 // '<' 1189 if (!TryConsumeToken(tok::less)) 1190 return false; 1191 1192 // An empty template argument list. 1193 if (Tok.is(tok::greater)) 1194 return true; 1195 1196 // See whether we have declaration specifiers, which indicate a type. 1197 while (isCXXDeclarationSpecifier() == TPResult::True) 1198 ConsumeToken(); 1199 1200 // If we have a '>' or a ',' then this is a template argument list. 1201 return Tok.is(tok::greater) || Tok.is(tok::comma); 1202 } 1203 1204 /// ParseTemplateArgumentList - Parse a C++ template-argument-list 1205 /// (C++ [temp.names]). Returns true if there was an error. 1206 /// 1207 /// template-argument-list: [C++ 14.2] 1208 /// template-argument 1209 /// template-argument-list ',' template-argument 1210 bool 1211 Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) { 1212 // Template argument lists are constant-evaluation contexts. 1213 EnterExpressionEvaluationContext EvalContext(Actions,Sema::ConstantEvaluated); 1214 ColonProtectionRAIIObject ColonProtection(*this, false); 1215 1216 do { 1217 ParsedTemplateArgument Arg = ParseTemplateArgument(); 1218 SourceLocation EllipsisLoc; 1219 if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) 1220 Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc); 1221 1222 if (Arg.isInvalid()) { 1223 SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch); 1224 return true; 1225 } 1226 1227 // Save this template argument. 1228 TemplateArgs.push_back(Arg); 1229 1230 // If the next token is a comma, consume it and keep reading 1231 // arguments. 1232 } while (TryConsumeToken(tok::comma)); 1233 1234 return false; 1235 } 1236 1237 /// \brief Parse a C++ explicit template instantiation 1238 /// (C++ [temp.explicit]). 1239 /// 1240 /// explicit-instantiation: 1241 /// 'extern' [opt] 'template' declaration 1242 /// 1243 /// Note that the 'extern' is a GNU extension and C++11 feature. 1244 Decl *Parser::ParseExplicitInstantiation(unsigned Context, 1245 SourceLocation ExternLoc, 1246 SourceLocation TemplateLoc, 1247 SourceLocation &DeclEnd, 1248 AccessSpecifier AS) { 1249 // This isn't really required here. 1250 ParsingDeclRAIIObject 1251 ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent); 1252 1253 return ParseSingleDeclarationAfterTemplate(Context, 1254 ParsedTemplateInfo(ExternLoc, 1255 TemplateLoc), 1256 ParsingTemplateParams, 1257 DeclEnd, AS); 1258 } 1259 1260 SourceRange Parser::ParsedTemplateInfo::getSourceRange() const { 1261 if (TemplateParams) 1262 return getTemplateParamsRange(TemplateParams->data(), 1263 TemplateParams->size()); 1264 1265 SourceRange R(TemplateLoc); 1266 if (ExternLoc.isValid()) 1267 R.setBegin(ExternLoc); 1268 return R; 1269 } 1270 1271 void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) { 1272 ((Parser *)P)->ParseLateTemplatedFuncDef(LPT); 1273 } 1274 1275 /// \brief Late parse a C++ function template in Microsoft mode. 1276 void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) { 1277 if (!LPT.D) 1278 return; 1279 1280 // Get the FunctionDecl. 1281 FunctionDecl *FunD = LPT.D->getAsFunction(); 1282 // Track template parameter depth. 1283 TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth); 1284 1285 // To restore the context after late parsing. 1286 Sema::ContextRAII GlobalSavedContext(Actions, Actions.CurContext); 1287 1288 SmallVector<ParseScope*, 4> TemplateParamScopeStack; 1289 1290 // Get the list of DeclContexts to reenter. 1291 SmallVector<DeclContext*, 4> DeclContextsToReenter; 1292 DeclContext *DD = FunD; 1293 while (DD && !DD->isTranslationUnit()) { 1294 DeclContextsToReenter.push_back(DD); 1295 DD = DD->getLexicalParent(); 1296 } 1297 1298 // Reenter template scopes from outermost to innermost. 1299 SmallVectorImpl<DeclContext *>::reverse_iterator II = 1300 DeclContextsToReenter.rbegin(); 1301 for (; II != DeclContextsToReenter.rend(); ++II) { 1302 TemplateParamScopeStack.push_back(new ParseScope(this, 1303 Scope::TemplateParamScope)); 1304 unsigned NumParamLists = 1305 Actions.ActOnReenterTemplateScope(getCurScope(), cast<Decl>(*II)); 1306 CurTemplateDepthTracker.addDepth(NumParamLists); 1307 if (*II != FunD) { 1308 TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope)); 1309 Actions.PushDeclContext(Actions.getCurScope(), *II); 1310 } 1311 } 1312 1313 assert(!LPT.Toks.empty() && "Empty body!"); 1314 1315 // Append the current token at the end of the new token stream so that it 1316 // doesn't get lost. 1317 LPT.Toks.push_back(Tok); 1318 PP.EnterTokenStream(LPT.Toks.data(), LPT.Toks.size(), true, false); 1319 1320 // Consume the previously pushed token. 1321 ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true); 1322 assert((Tok.is(tok::l_brace) || Tok.is(tok::colon) || Tok.is(tok::kw_try)) 1323 && "Inline method not starting with '{', ':' or 'try'"); 1324 1325 // Parse the method body. Function body parsing code is similar enough 1326 // to be re-used for method bodies as well. 1327 ParseScope FnScope(this, Scope::FnScope|Scope::DeclScope); 1328 1329 // Recreate the containing function DeclContext. 1330 Sema::ContextRAII FunctionSavedContext(Actions, Actions.getContainingDC(FunD)); 1331 1332 Actions.ActOnStartOfFunctionDef(getCurScope(), FunD); 1333 1334 if (Tok.is(tok::kw_try)) { 1335 ParseFunctionTryBlock(LPT.D, FnScope); 1336 } else { 1337 if (Tok.is(tok::colon)) 1338 ParseConstructorInitializer(LPT.D); 1339 else 1340 Actions.ActOnDefaultCtorInitializers(LPT.D); 1341 1342 if (Tok.is(tok::l_brace)) { 1343 assert((!isa<FunctionTemplateDecl>(LPT.D) || 1344 cast<FunctionTemplateDecl>(LPT.D) 1345 ->getTemplateParameters() 1346 ->getDepth() == TemplateParameterDepth - 1) && 1347 "TemplateParameterDepth should be greater than the depth of " 1348 "current template being instantiated!"); 1349 ParseFunctionStatementBody(LPT.D, FnScope); 1350 Actions.UnmarkAsLateParsedTemplate(FunD); 1351 } else 1352 Actions.ActOnFinishFunctionBody(LPT.D, nullptr); 1353 } 1354 1355 // Exit scopes. 1356 FnScope.Exit(); 1357 SmallVectorImpl<ParseScope *>::reverse_iterator I = 1358 TemplateParamScopeStack.rbegin(); 1359 for (; I != TemplateParamScopeStack.rend(); ++I) 1360 delete *I; 1361 } 1362 1363 /// \brief Lex a delayed template function for late parsing. 1364 void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) { 1365 tok::TokenKind kind = Tok.getKind(); 1366 if (!ConsumeAndStoreFunctionPrologue(Toks)) { 1367 // Consume everything up to (and including) the matching right brace. 1368 ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false); 1369 } 1370 1371 // If we're in a function-try-block, we need to store all the catch blocks. 1372 if (kind == tok::kw_try) { 1373 while (Tok.is(tok::kw_catch)) { 1374 ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false); 1375 ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false); 1376 } 1377 } 1378 } 1379
