//===--- ParseTemplate.cpp - Template Parsing -----------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements parsing of C++ templates. // //===----------------------------------------------------------------------===// #include "clang/Parse/Parser.h" #include "RAIIObjectsForParser.h" #include "clang/AST/ASTConsumer.h" #include "clang/AST/DeclTemplate.h" #include "clang/Parse/ParseDiagnostic.h" #include "clang/Sema/DeclSpec.h" #include "clang/Sema/ParsedTemplate.h" #include "clang/Sema/Scope.h" using namespace clang; /// \brief Parse a template declaration, explicit instantiation, or /// explicit specialization. Decl * Parser::ParseDeclarationStartingWithTemplate(unsigned Context, SourceLocation &DeclEnd, AccessSpecifier AS, AttributeList *AccessAttrs) { ObjCDeclContextSwitch ObjCDC(*this); if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) { return ParseExplicitInstantiation(Context, SourceLocation(), ConsumeToken(), DeclEnd, AS); } return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS, AccessAttrs); } /// \brief Parse a template declaration or an explicit specialization. /// /// Template declarations include one or more template parameter lists /// and either the function or class template declaration. Explicit /// specializations contain one or more 'template < >' prefixes /// followed by a (possibly templated) declaration. Since the /// syntactic form of both features is nearly identical, we parse all /// of the template headers together and let semantic analysis sort /// the declarations from the explicit specializations. /// /// template-declaration: [C++ temp] /// 'export'[opt] 'template' '<' template-parameter-list '>' declaration /// /// explicit-specialization: [ C++ temp.expl.spec] /// 'template' '<' '>' declaration Decl * Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context, SourceLocation &DeclEnd, AccessSpecifier AS, AttributeList *AccessAttrs) { assert((Tok.is(tok::kw_export) || Tok.is(tok::kw_template)) && "Token does not start a template declaration."); // Enter template-parameter scope. ParseScope TemplateParmScope(this, Scope::TemplateParamScope); // Tell the action that names should be checked in the context of // the declaration to come. ParsingDeclRAIIObject ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent); // Parse multiple levels of template headers within this template // parameter scope, e.g., // // template<typename T> // template<typename U> // class A<T>::B { ... }; // // We parse multiple levels non-recursively so that we can build a // single data structure containing all of the template parameter // lists to easily differentiate between the case above and: // // template<typename T> // class A { // template<typename U> class B; // }; // // In the first case, the action for declaring A<T>::B receives // both template parameter lists. In the second case, the action for // defining A<T>::B receives just the inner template parameter list // (and retrieves the outer template parameter list from its // context). bool isSpecialization = true; bool LastParamListWasEmpty = false; TemplateParameterLists ParamLists; TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth); do { // Consume the 'export', if any. SourceLocation ExportLoc; TryConsumeToken(tok::kw_export, ExportLoc); // Consume the 'template', which should be here. SourceLocation TemplateLoc; if (!TryConsumeToken(tok::kw_template, TemplateLoc)) { Diag(Tok.getLocation(), diag::err_expected_template); return nullptr; } // Parse the '<' template-parameter-list '>' SourceLocation LAngleLoc, RAngleLoc; SmallVector<Decl*, 4> TemplateParams; if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(), TemplateParams, LAngleLoc, RAngleLoc)) { // Skip until the semi-colon or a }. SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch); TryConsumeToken(tok::semi); return nullptr; } ParamLists.push_back( Actions.ActOnTemplateParameterList(CurTemplateDepthTracker.getDepth(), ExportLoc, TemplateLoc, LAngleLoc, TemplateParams.data(), TemplateParams.size(), RAngleLoc)); if (!TemplateParams.empty()) { isSpecialization = false; ++CurTemplateDepthTracker; } else { LastParamListWasEmpty = true; } } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template)); // Parse the actual template declaration. return ParseSingleDeclarationAfterTemplate(Context, ParsedTemplateInfo(&ParamLists, isSpecialization, LastParamListWasEmpty), ParsingTemplateParams, DeclEnd, AS, AccessAttrs); } /// \brief Parse a single declaration that declares a template, /// template specialization, or explicit instantiation of a template. /// /// \param DeclEnd will receive the source location of the last token /// within this declaration. /// /// \param AS the access specifier associated with this /// declaration. Will be AS_none for namespace-scope declarations. /// /// \returns the new declaration. Decl * Parser::ParseSingleDeclarationAfterTemplate( unsigned Context, const ParsedTemplateInfo &TemplateInfo, ParsingDeclRAIIObject &DiagsFromTParams, SourceLocation &DeclEnd, AccessSpecifier AS, AttributeList *AccessAttrs) { assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate && "Template information required"); if (Context == Declarator::MemberContext) { // We are parsing a member template. ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo, &DiagsFromTParams); return nullptr; } ParsedAttributesWithRange prefixAttrs(AttrFactory); MaybeParseCXX11Attributes(prefixAttrs); if (Tok.is(tok::kw_using)) return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd, prefixAttrs); // Parse the declaration specifiers, stealing any diagnostics from // the template parameters. ParsingDeclSpec DS(*this, &DiagsFromTParams); ParseDeclarationSpecifiers(DS, TemplateInfo, AS, getDeclSpecContextFromDeclaratorContext(Context)); if (Tok.is(tok::semi)) { ProhibitAttributes(prefixAttrs); DeclEnd = ConsumeToken(); Decl *Decl = Actions.ParsedFreeStandingDeclSpec( getCurScope(), AS, DS, TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams : MultiTemplateParamsArg(), TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation); DS.complete(Decl); return Decl; } // Move the attributes from the prefix into the DS. if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) ProhibitAttributes(prefixAttrs); else DS.takeAttributesFrom(prefixAttrs); // Parse the declarator. ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context); ParseDeclarator(DeclaratorInfo); // Error parsing the declarator? if (!DeclaratorInfo.hasName()) { // If so, skip until the semi-colon or a }. SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch); if (Tok.is(tok::semi)) ConsumeToken(); return nullptr; } LateParsedAttrList LateParsedAttrs(true); if (DeclaratorInfo.isFunctionDeclarator()) MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs); if (DeclaratorInfo.isFunctionDeclarator() && isStartOfFunctionDefinition(DeclaratorInfo)) { if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) { // Recover by ignoring the 'typedef'. This was probably supposed to be // the 'typename' keyword, which we should have already suggested adding // if it's appropriate. Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef) << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc()); DS.ClearStorageClassSpecs(); } if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) { if (DeclaratorInfo.getName().getKind() != UnqualifiedId::IK_TemplateId) { // If the declarator-id is not a template-id, issue a diagnostic and // recover by ignoring the 'template' keyword. Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0; return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(), &LateParsedAttrs); } else { SourceLocation LAngleLoc = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc); Diag(DeclaratorInfo.getIdentifierLoc(), diag::err_explicit_instantiation_with_definition) << SourceRange(TemplateInfo.TemplateLoc) << FixItHint::CreateInsertion(LAngleLoc, "<>"); // Recover as if it were an explicit specialization. TemplateParameterLists FakedParamLists; FakedParamLists.push_back(Actions.ActOnTemplateParameterList( 0, SourceLocation(), TemplateInfo.TemplateLoc, LAngleLoc, nullptr, 0, LAngleLoc)); return ParseFunctionDefinition( DeclaratorInfo, ParsedTemplateInfo(&FakedParamLists, /*isSpecialization=*/true, /*LastParamListWasEmpty=*/true), &LateParsedAttrs); } } return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo, &LateParsedAttrs); } // Parse this declaration. Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo, TemplateInfo); if (Tok.is(tok::comma)) { Diag(Tok, diag::err_multiple_template_declarators) << (int)TemplateInfo.Kind; SkipUntil(tok::semi); return ThisDecl; } // Eat the semi colon after the declaration. ExpectAndConsumeSemi(diag::err_expected_semi_declaration); if (LateParsedAttrs.size() > 0) ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false); DeclaratorInfo.complete(ThisDecl); return ThisDecl; } /// ParseTemplateParameters - Parses a template-parameter-list enclosed in /// angle brackets. Depth is the depth of this template-parameter-list, which /// is the number of template headers directly enclosing this template header. /// TemplateParams is the current list of template parameters we're building. /// The template parameter we parse will be added to this list. LAngleLoc and /// RAngleLoc will receive the positions of the '<' and '>', respectively, /// that enclose this template parameter list. /// /// \returns true if an error occurred, false otherwise. bool Parser::ParseTemplateParameters(unsigned Depth, SmallVectorImpl<Decl*> &TemplateParams, SourceLocation &LAngleLoc, SourceLocation &RAngleLoc) { // Get the template parameter list. if (!TryConsumeToken(tok::less, LAngleLoc)) { Diag(Tok.getLocation(), diag::err_expected_less_after) << "template"; return true; } // Try to parse the template parameter list. bool Failed = false; if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater)) Failed = ParseTemplateParameterList(Depth, TemplateParams); if (Tok.is(tok::greatergreater)) { // No diagnostic required here: a template-parameter-list can only be // followed by a declaration or, for a template template parameter, the // 'class' keyword. Therefore, the second '>' will be diagnosed later. // This matters for elegant diagnosis of: // template<template<typename>> struct S; Tok.setKind(tok::greater); RAngleLoc = Tok.getLocation(); Tok.setLocation(Tok.getLocation().getLocWithOffset(1)); } else if (!TryConsumeToken(tok::greater, RAngleLoc) && Failed) { Diag(Tok.getLocation(), diag::err_expected) << tok::greater; return true; } return false; } /// ParseTemplateParameterList - Parse a template parameter list. If /// the parsing fails badly (i.e., closing bracket was left out), this /// will try to put the token stream in a reasonable position (closing /// a statement, etc.) and return false. /// /// template-parameter-list: [C++ temp] /// template-parameter /// template-parameter-list ',' template-parameter bool Parser::ParseTemplateParameterList(unsigned Depth, SmallVectorImpl<Decl*> &TemplateParams) { while (1) { if (Decl *TmpParam = ParseTemplateParameter(Depth, TemplateParams.size())) { TemplateParams.push_back(TmpParam); } else { // If we failed to parse a template parameter, skip until we find // a comma or closing brace. SkipUntil(tok::comma, tok::greater, tok::greatergreater, StopAtSemi | StopBeforeMatch); } // Did we find a comma or the end of the template parameter list? if (Tok.is(tok::comma)) { ConsumeToken(); } else if (Tok.is(tok::greater) || Tok.is(tok::greatergreater)) { // Don't consume this... that's done by template parser. break; } else { // Somebody probably forgot to close the template. Skip ahead and // try to get out of the expression. This error is currently // subsumed by whatever goes on in ParseTemplateParameter. Diag(Tok.getLocation(), diag::err_expected_comma_greater); SkipUntil(tok::comma, tok::greater, tok::greatergreater, StopAtSemi | StopBeforeMatch); return false; } } return true; } /// \brief Determine whether the parser is at the start of a template /// type parameter. bool Parser::isStartOfTemplateTypeParameter() { if (Tok.is(tok::kw_class)) { // "class" may be the start of an elaborated-type-specifier or a // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter. switch (NextToken().getKind()) { case tok::equal: case tok::comma: case tok::greater: case tok::greatergreater: case tok::ellipsis: return true; case tok::identifier: // This may be either a type-parameter or an elaborated-type-specifier. // We have to look further. break; default: return false; } switch (GetLookAheadToken(2).getKind()) { case tok::equal: case tok::comma: case tok::greater: case tok::greatergreater: return true; default: return false; } } if (Tok.isNot(tok::kw_typename)) return false; // C++ [temp.param]p2: // There is no semantic difference between class and typename in a // template-parameter. typename followed by an unqualified-id // names a template type parameter. typename followed by a // qualified-id denotes the type in a non-type // parameter-declaration. Token Next = NextToken(); // If we have an identifier, skip over it. if (Next.getKind() == tok::identifier) Next = GetLookAheadToken(2); switch (Next.getKind()) { case tok::equal: case tok::comma: case tok::greater: case tok::greatergreater: case tok::ellipsis: return true; default: return false; } } /// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]). /// /// template-parameter: [C++ temp.param] /// type-parameter /// parameter-declaration /// /// type-parameter: (see below) /// 'class' ...[opt] identifier[opt] /// 'class' identifier[opt] '=' type-id /// 'typename' ...[opt] identifier[opt] /// 'typename' identifier[opt] '=' type-id /// 'template' '<' template-parameter-list '>' /// 'class' ...[opt] identifier[opt] /// 'template' '<' template-parameter-list '>' 'class' identifier[opt] /// = id-expression Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { if (isStartOfTemplateTypeParameter()) return ParseTypeParameter(Depth, Position); if (Tok.is(tok::kw_template)) return ParseTemplateTemplateParameter(Depth, Position); // If it's none of the above, then it must be a parameter declaration. // NOTE: This will pick up errors in the closure of the template parameter // list (e.g., template < ; Check here to implement >> style closures. return ParseNonTypeTemplateParameter(Depth, Position); } /// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]). /// Other kinds of template parameters are parsed in /// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter. /// /// type-parameter: [C++ temp.param] /// 'class' ...[opt][C++0x] identifier[opt] /// 'class' identifier[opt] '=' type-id /// 'typename' ...[opt][C++0x] identifier[opt] /// 'typename' identifier[opt] '=' type-id Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) { assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) && "A type-parameter starts with 'class' or 'typename'"); // Consume the 'class' or 'typename' keyword. bool TypenameKeyword = Tok.is(tok::kw_typename); SourceLocation KeyLoc = ConsumeToken(); // Grab the ellipsis (if given). SourceLocation EllipsisLoc; if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) { Diag(EllipsisLoc, getLangOpts().CPlusPlus11 ? diag::warn_cxx98_compat_variadic_templates : diag::ext_variadic_templates); } // Grab the template parameter name (if given) SourceLocation NameLoc; IdentifierInfo *ParamName = nullptr; if (Tok.is(tok::identifier)) { ParamName = Tok.getIdentifierInfo(); NameLoc = ConsumeToken(); } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater) || Tok.is(tok::greatergreater)) { // Unnamed template parameter. Don't have to do anything here, just // don't consume this token. } else { Diag(Tok.getLocation(), diag::err_expected) << tok::identifier; return nullptr; } // Recover from misplaced ellipsis. bool AlreadyHasEllipsis = EllipsisLoc.isValid(); if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true); // Grab a default argument (if available). // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before // we introduce the type parameter into the local scope. SourceLocation EqualLoc; ParsedType DefaultArg; if (TryConsumeToken(tok::equal, EqualLoc)) DefaultArg = ParseTypeName(/*Range=*/nullptr, Declarator::TemplateTypeArgContext).get(); return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, EllipsisLoc, KeyLoc, ParamName, NameLoc, Depth, Position, EqualLoc, DefaultArg); } /// ParseTemplateTemplateParameter - Handle the parsing of template /// template parameters. /// /// type-parameter: [C++ temp.param] /// 'template' '<' template-parameter-list '>' type-parameter-key /// ...[opt] identifier[opt] /// 'template' '<' template-parameter-list '>' type-parameter-key /// identifier[opt] = id-expression /// type-parameter-key: /// 'class' /// 'typename' [C++1z] Decl * Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); // Handle the template <...> part. SourceLocation TemplateLoc = ConsumeToken(); SmallVector<Decl*,8> TemplateParams; SourceLocation LAngleLoc, RAngleLoc; { ParseScope TemplateParmScope(this, Scope::TemplateParamScope); if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, RAngleLoc)) { return nullptr; } } // Provide an ExtWarn if the C++1z feature of using 'typename' here is used. // Generate a meaningful error if the user forgot to put class before the // identifier, comma, or greater. Provide a fixit if the identifier, comma, // or greater appear immediately or after 'struct'. In the latter case, // replace the keyword with 'class'. if (!TryConsumeToken(tok::kw_class)) { bool Replace = Tok.is(tok::kw_typename) || Tok.is(tok::kw_struct); const Token &Next = Tok.is(tok::kw_struct) ? NextToken() : Tok; if (Tok.is(tok::kw_typename)) { Diag(Tok.getLocation(), getLangOpts().CPlusPlus1z ? diag::warn_cxx1y_compat_template_template_param_typename : diag::ext_template_template_param_typename) << (!getLangOpts().CPlusPlus1z ? FixItHint::CreateReplacement(Tok.getLocation(), "class") : FixItHint()); } else if (Next.is(tok::identifier) || Next.is(tok::comma) || Next.is(tok::greater) || Next.is(tok::greatergreater) || Next.is(tok::ellipsis)) { Diag(Tok.getLocation(), diag::err_class_on_template_template_param) << (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class") : FixItHint::CreateInsertion(Tok.getLocation(), "class ")); } else Diag(Tok.getLocation(), diag::err_class_on_template_template_param); if (Replace) ConsumeToken(); } // Parse the ellipsis, if given. SourceLocation EllipsisLoc; if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) Diag(EllipsisLoc, getLangOpts().CPlusPlus11 ? diag::warn_cxx98_compat_variadic_templates : diag::ext_variadic_templates); // Get the identifier, if given. SourceLocation NameLoc; IdentifierInfo *ParamName = nullptr; if (Tok.is(tok::identifier)) { ParamName = Tok.getIdentifierInfo(); NameLoc = ConsumeToken(); } else if (Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater) || Tok.is(tok::greatergreater)) { // Unnamed template parameter. Don't have to do anything here, just // don't consume this token. } else { Diag(Tok.getLocation(), diag::err_expected) << tok::identifier; return nullptr; } // Recover from misplaced ellipsis. bool AlreadyHasEllipsis = EllipsisLoc.isValid(); if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true); TemplateParameterList *ParamList = Actions.ActOnTemplateParameterList(Depth, SourceLocation(), TemplateLoc, LAngleLoc, TemplateParams.data(), TemplateParams.size(), RAngleLoc); // Grab a default argument (if available). // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before // we introduce the template parameter into the local scope. SourceLocation EqualLoc; ParsedTemplateArgument DefaultArg; if (TryConsumeToken(tok::equal, EqualLoc)) { DefaultArg = ParseTemplateTemplateArgument(); if (DefaultArg.isInvalid()) { Diag(Tok.getLocation(), diag::err_default_template_template_parameter_not_template); SkipUntil(tok::comma, tok::greater, tok::greatergreater, StopAtSemi | StopBeforeMatch); } } return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc, ParamList, EllipsisLoc, ParamName, NameLoc, Depth, Position, EqualLoc, DefaultArg); } /// ParseNonTypeTemplateParameter - Handle the parsing of non-type /// template parameters (e.g., in "template<int Size> class array;"). /// /// template-parameter: /// ... /// parameter-declaration Decl * Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { // Parse the declaration-specifiers (i.e., the type). // FIXME: The type should probably be restricted in some way... Not all // declarators (parts of declarators?) are accepted for parameters. DeclSpec DS(AttrFactory); ParseDeclarationSpecifiers(DS); // Parse this as a typename. Declarator ParamDecl(DS, Declarator::TemplateParamContext); ParseDeclarator(ParamDecl); if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) { Diag(Tok.getLocation(), diag::err_expected_template_parameter); return nullptr; } // Recover from misplaced ellipsis. SourceLocation EllipsisLoc; if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, ParamDecl); // If there is a default value, parse it. // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before // we introduce the template parameter into the local scope. SourceLocation EqualLoc; ExprResult DefaultArg; if (TryConsumeToken(tok::equal, EqualLoc)) { // C++ [temp.param]p15: // When parsing a default template-argument for a non-type // template-parameter, the first non-nested > is taken as the // end of the template-parameter-list rather than a greater-than // operator. GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated); DefaultArg = ParseAssignmentExpression(); if (DefaultArg.isInvalid()) SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch); } // Create the parameter. return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl, Depth, Position, EqualLoc, DefaultArg.get()); } void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc, SourceLocation CorrectLoc, bool AlreadyHasEllipsis, bool IdentifierHasName) { FixItHint Insertion; if (!AlreadyHasEllipsis) Insertion = FixItHint::CreateInsertion(CorrectLoc, "..."); Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration) << FixItHint::CreateRemoval(EllipsisLoc) << Insertion << !IdentifierHasName; } void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc, Declarator &D) { assert(EllipsisLoc.isValid()); bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid(); if (!AlreadyHasEllipsis) D.setEllipsisLoc(EllipsisLoc); DiagnoseMisplacedEllipsis(EllipsisLoc, D.getIdentifierLoc(), AlreadyHasEllipsis, D.hasName()); } /// \brief Parses a '>' at the end of a template list. /// /// If this function encounters '>>', '>>>', '>=', or '>>=', it tries /// to determine if these tokens were supposed to be a '>' followed by /// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary. /// /// \param RAngleLoc the location of the consumed '>'. /// /// \param ConsumeLastToken if true, the '>' is not consumed. /// /// \returns true, if current token does not start with '>', false otherwise. bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc, bool ConsumeLastToken) { // What will be left once we've consumed the '>'. tok::TokenKind RemainingToken; const char *ReplacementStr = "> >"; switch (Tok.getKind()) { default: Diag(Tok.getLocation(), diag::err_expected) << tok::greater; return true; case tok::greater: // Determine the location of the '>' token. Only consume this token // if the caller asked us to. RAngleLoc = Tok.getLocation(); if (ConsumeLastToken) ConsumeToken(); return false; case tok::greatergreater: RemainingToken = tok::greater; break; case tok::greatergreatergreater: RemainingToken = tok::greatergreater; break; case tok::greaterequal: RemainingToken = tok::equal; ReplacementStr = "> ="; break; case tok::greatergreaterequal: RemainingToken = tok::greaterequal; break; } // This template-id is terminated by a token which starts with a '>'. Outside // C++11, this is now error recovery, and in C++11, this is error recovery if // the token isn't '>>' or '>>>'. // '>>>' is for CUDA, where this sequence of characters is parsed into // tok::greatergreatergreater, rather than two separate tokens. RAngleLoc = Tok.getLocation(); // The source range of the '>>' or '>=' at the start of the token. CharSourceRange ReplacementRange = CharSourceRange::getCharRange(RAngleLoc, Lexer::AdvanceToTokenCharacter(RAngleLoc, 2, PP.getSourceManager(), getLangOpts())); // A hint to put a space between the '>>'s. In order to make the hint as // clear as possible, we include the characters either side of the space in // the replacement, rather than just inserting a space at SecondCharLoc. FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange, ReplacementStr); // A hint to put another space after the token, if it would otherwise be // lexed differently. FixItHint Hint2; Token Next = NextToken(); if ((RemainingToken == tok::greater || RemainingToken == tok::greatergreater) && (Next.is(tok::greater) || Next.is(tok::greatergreater) || Next.is(tok::greatergreatergreater) || Next.is(tok::equal) || Next.is(tok::greaterequal) || Next.is(tok::greatergreaterequal) || Next.is(tok::equalequal)) && areTokensAdjacent(Tok, Next)) Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " "); unsigned DiagId = diag::err_two_right_angle_brackets_need_space; if (getLangOpts().CPlusPlus11 && (Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater))) DiagId = diag::warn_cxx98_compat_two_right_angle_brackets; else if (Tok.is(tok::greaterequal)) DiagId = diag::err_right_angle_bracket_equal_needs_space; Diag(Tok.getLocation(), DiagId) << Hint1 << Hint2; // Strip the initial '>' from the token. if (RemainingToken == tok::equal && Next.is(tok::equal) && areTokensAdjacent(Tok, Next)) { // Join two adjacent '=' tokens into one, for cases like: // void (*p)() = f<int>; // return f<int>==p; ConsumeToken(); Tok.setKind(tok::equalequal); Tok.setLength(Tok.getLength() + 1); } else { Tok.setKind(RemainingToken); Tok.setLength(Tok.getLength() - 1); } Tok.setLocation(Lexer::AdvanceToTokenCharacter(RAngleLoc, 1, PP.getSourceManager(), getLangOpts())); if (!ConsumeLastToken) { // Since we're not supposed to consume the '>' token, we need to push // this token and revert the current token back to the '>'. PP.EnterToken(Tok); Tok.setKind(tok::greater); Tok.setLength(1); Tok.setLocation(RAngleLoc); } return false; } /// \brief Parses a template-id that after the template name has /// already been parsed. /// /// This routine takes care of parsing the enclosed template argument /// list ('<' template-parameter-list [opt] '>') and placing the /// results into a form that can be transferred to semantic analysis. /// /// \param Template the template declaration produced by isTemplateName /// /// \param TemplateNameLoc the source location of the template name /// /// \param SS if non-NULL, the nested-name-specifier preceding the /// template name. /// /// \param ConsumeLastToken if true, then we will consume the last /// token that forms the template-id. Otherwise, we will leave the /// last token in the stream (e.g., so that it can be replaced with an /// annotation token). bool Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template, SourceLocation TemplateNameLoc, const CXXScopeSpec &SS, bool ConsumeLastToken, SourceLocation &LAngleLoc, TemplateArgList &TemplateArgs, SourceLocation &RAngleLoc) { assert(Tok.is(tok::less) && "Must have already parsed the template-name"); // Consume the '<'. LAngleLoc = ConsumeToken(); // Parse the optional template-argument-list. bool Invalid = false; { GreaterThanIsOperatorScope G(GreaterThanIsOperator, false); if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) Invalid = ParseTemplateArgumentList(TemplateArgs); if (Invalid) { // Try to find the closing '>'. if (ConsumeLastToken) SkipUntil(tok::greater, StopAtSemi); else SkipUntil(tok::greater, StopAtSemi | StopBeforeMatch); return true; } } return ParseGreaterThanInTemplateList(RAngleLoc, ConsumeLastToken); } /// \brief Replace the tokens that form a simple-template-id with an /// annotation token containing the complete template-id. /// /// The first token in the stream must be the name of a template that /// is followed by a '<'. This routine will parse the complete /// simple-template-id and replace the tokens with a single annotation /// token with one of two different kinds: if the template-id names a /// type (and \p AllowTypeAnnotation is true), the annotation token is /// a type annotation that includes the optional nested-name-specifier /// (\p SS). Otherwise, the annotation token is a template-id /// annotation that does not include the optional /// nested-name-specifier. /// /// \param Template the declaration of the template named by the first /// token (an identifier), as returned from \c Action::isTemplateName(). /// /// \param TNK the kind of template that \p Template /// refers to, as returned from \c Action::isTemplateName(). /// /// \param SS if non-NULL, the nested-name-specifier that precedes /// this template name. /// /// \param TemplateKWLoc if valid, specifies that this template-id /// annotation was preceded by the 'template' keyword and gives the /// location of that keyword. If invalid (the default), then this /// template-id was not preceded by a 'template' keyword. /// /// \param AllowTypeAnnotation if true (the default), then a /// simple-template-id that refers to a class template, template /// template parameter, or other template that produces a type will be /// replaced with a type annotation token. Otherwise, the /// simple-template-id is always replaced with a template-id /// annotation token. /// /// If an unrecoverable parse error occurs and no annotation token can be /// formed, this function returns true. /// bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK, CXXScopeSpec &SS, SourceLocation TemplateKWLoc, UnqualifiedId &TemplateName, bool AllowTypeAnnotation) { assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++"); assert(Template && Tok.is(tok::less) && "Parser isn't at the beginning of a template-id"); // Consume the template-name. SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin(); // Parse the enclosed template argument list. SourceLocation LAngleLoc, RAngleLoc; TemplateArgList TemplateArgs; bool Invalid = ParseTemplateIdAfterTemplateName(Template, TemplateNameLoc, SS, false, LAngleLoc, TemplateArgs, RAngleLoc); if (Invalid) { // If we failed to parse the template ID but skipped ahead to a >, we're not // going to be able to form a token annotation. Eat the '>' if present. TryConsumeToken(tok::greater); return true; } ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs); // Build the annotation token. if (TNK == TNK_Type_template && AllowTypeAnnotation) { TypeResult Type = Actions.ActOnTemplateIdType(SS, TemplateKWLoc, Template, TemplateNameLoc, LAngleLoc, TemplateArgsPtr, RAngleLoc); if (Type.isInvalid()) { // If we failed to parse the template ID but skipped ahead to a >, we're not // going to be able to form a token annotation. Eat the '>' if present. TryConsumeToken(tok::greater); return true; } Tok.setKind(tok::annot_typename); setTypeAnnotation(Tok, Type.get()); if (SS.isNotEmpty()) Tok.setLocation(SS.getBeginLoc()); else if (TemplateKWLoc.isValid()) Tok.setLocation(TemplateKWLoc); else Tok.setLocation(TemplateNameLoc); } else { // Build a template-id annotation token that can be processed // later. Tok.setKind(tok::annot_template_id); TemplateIdAnnotation *TemplateId = TemplateIdAnnotation::Allocate(TemplateArgs.size(), TemplateIds); TemplateId->TemplateNameLoc = TemplateNameLoc; if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) { TemplateId->Name = TemplateName.Identifier; TemplateId->Operator = OO_None; } else { TemplateId->Name = nullptr; TemplateId->Operator = TemplateName.OperatorFunctionId.Operator; } TemplateId->SS = SS; TemplateId->TemplateKWLoc = TemplateKWLoc; TemplateId->Template = Template; TemplateId->Kind = TNK; TemplateId->LAngleLoc = LAngleLoc; TemplateId->RAngleLoc = RAngleLoc; ParsedTemplateArgument *Args = TemplateId->getTemplateArgs(); for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) Args[Arg] = ParsedTemplateArgument(TemplateArgs[Arg]); Tok.setAnnotationValue(TemplateId); if (TemplateKWLoc.isValid()) Tok.setLocation(TemplateKWLoc); else Tok.setLocation(TemplateNameLoc); } // Common fields for the annotation token Tok.setAnnotationEndLoc(RAngleLoc); // In case the tokens were cached, have Preprocessor replace them with the // annotation token. PP.AnnotateCachedTokens(Tok); return false; } /// \brief Replaces a template-id annotation token with a type /// annotation token. /// /// If there was a failure when forming the type from the template-id, /// a type annotation token will still be created, but will have a /// NULL type pointer to signify an error. void Parser::AnnotateTemplateIdTokenAsType() { assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens"); TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok); assert((TemplateId->Kind == TNK_Type_template || TemplateId->Kind == TNK_Dependent_template_name) && "Only works for type and dependent templates"); ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(), TemplateId->NumArgs); TypeResult Type = Actions.ActOnTemplateIdType(TemplateId->SS, TemplateId->TemplateKWLoc, TemplateId->Template, TemplateId->TemplateNameLoc, TemplateId->LAngleLoc, TemplateArgsPtr, TemplateId->RAngleLoc); // Create the new "type" annotation token. Tok.setKind(tok::annot_typename); setTypeAnnotation(Tok, Type.isInvalid() ? ParsedType() : Type.get()); if (TemplateId->SS.isNotEmpty()) // it was a C++ qualified type name. Tok.setLocation(TemplateId->SS.getBeginLoc()); // End location stays the same // Replace the template-id annotation token, and possible the scope-specifier // that precedes it, with the typename annotation token. PP.AnnotateCachedTokens(Tok); } /// \brief Determine whether the given token can end a template argument. static bool isEndOfTemplateArgument(Token Tok) { return Tok.is(tok::comma) || Tok.is(tok::greater) || Tok.is(tok::greatergreater); } /// \brief Parse a C++ template template argument. ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() { if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) && !Tok.is(tok::annot_cxxscope)) return ParsedTemplateArgument(); // C++0x [temp.arg.template]p1: // A template-argument for a template template-parameter shall be the name // of a class template or an alias template, expressed as id-expression. // // We parse an id-expression that refers to a class template or alias // template. The grammar we parse is: // // nested-name-specifier[opt] template[opt] identifier ...[opt] // // followed by a token that terminates a template argument, such as ',', // '>', or (in some cases) '>>'. CXXScopeSpec SS; // nested-name-specifier, if present ParseOptionalCXXScopeSpecifier(SS, ParsedType(), /*EnteringContext=*/false); ParsedTemplateArgument Result; SourceLocation EllipsisLoc; if (SS.isSet() && Tok.is(tok::kw_template)) { // Parse the optional 'template' keyword following the // nested-name-specifier. SourceLocation TemplateKWLoc = ConsumeToken(); if (Tok.is(tok::identifier)) { // We appear to have a dependent template name. UnqualifiedId Name; Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); ConsumeToken(); // the identifier TryConsumeToken(tok::ellipsis, EllipsisLoc); // If the next token signals the end of a template argument, // then we have a dependent template name that could be a template // template argument. TemplateTy Template; if (isEndOfTemplateArgument(Tok) && Actions.ActOnDependentTemplateName(getCurScope(), SS, TemplateKWLoc, Name, /*ObjectType=*/ ParsedType(), /*EnteringContext=*/false, Template)) Result = ParsedTemplateArgument(SS, Template, Name.StartLocation); } } else if (Tok.is(tok::identifier)) { // We may have a (non-dependent) template name. TemplateTy Template; UnqualifiedId Name; Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation()); ConsumeToken(); // the identifier TryConsumeToken(tok::ellipsis, EllipsisLoc); if (isEndOfTemplateArgument(Tok)) { bool MemberOfUnknownSpecialization; TemplateNameKind TNK = Actions.isTemplateName(getCurScope(), SS, /*hasTemplateKeyword=*/false, Name, /*ObjectType=*/ ParsedType(), /*EnteringContext=*/false, Template, MemberOfUnknownSpecialization); if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) { // We have an id-expression that refers to a class template or // (C++0x) alias template. Result = ParsedTemplateArgument(SS, Template, Name.StartLocation); } } } // If this is a pack expansion, build it as such. if (EllipsisLoc.isValid() && !Result.isInvalid()) Result = Actions.ActOnPackExpansion(Result, EllipsisLoc); return Result; } /// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). /// /// template-argument: [C++ 14.2] /// constant-expression /// type-id /// id-expression ParsedTemplateArgument Parser::ParseTemplateArgument() { // C++ [temp.arg]p2: // In a template-argument, an ambiguity between a type-id and an // expression is resolved to a type-id, regardless of the form of // the corresponding template-parameter. // // Therefore, we initially try to parse a type-id. if (isCXXTypeId(TypeIdAsTemplateArgument)) { SourceLocation Loc = Tok.getLocation(); TypeResult TypeArg = ParseTypeName(/*Range=*/nullptr, Declarator::TemplateTypeArgContext); if (TypeArg.isInvalid()) return ParsedTemplateArgument(); return ParsedTemplateArgument(ParsedTemplateArgument::Type, TypeArg.get().getAsOpaquePtr(), Loc); } // Try to parse a template template argument. { TentativeParsingAction TPA(*this); ParsedTemplateArgument TemplateTemplateArgument = ParseTemplateTemplateArgument(); if (!TemplateTemplateArgument.isInvalid()) { TPA.Commit(); return TemplateTemplateArgument; } // Revert this tentative parse to parse a non-type template argument. TPA.Revert(); } // Parse a non-type template argument. SourceLocation Loc = Tok.getLocation(); ExprResult ExprArg = ParseConstantExpression(MaybeTypeCast); if (ExprArg.isInvalid() || !ExprArg.get()) return ParsedTemplateArgument(); return ParsedTemplateArgument(ParsedTemplateArgument::NonType, ExprArg.get(), Loc); } /// \brief Determine whether the current tokens can only be parsed as a /// template argument list (starting with the '<') and never as a '<' /// expression. bool Parser::IsTemplateArgumentList(unsigned Skip) { struct AlwaysRevertAction : TentativeParsingAction { AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { } ~AlwaysRevertAction() { Revert(); } } Tentative(*this); while (Skip) { ConsumeToken(); --Skip; } // '<' if (!TryConsumeToken(tok::less)) return false; // An empty template argument list. if (Tok.is(tok::greater)) return true; // See whether we have declaration specifiers, which indicate a type. while (isCXXDeclarationSpecifier() == TPResult::True) ConsumeToken(); // If we have a '>' or a ',' then this is a template argument list. return Tok.is(tok::greater) || Tok.is(tok::comma); } /// ParseTemplateArgumentList - Parse a C++ template-argument-list /// (C++ [temp.names]). Returns true if there was an error. /// /// template-argument-list: [C++ 14.2] /// template-argument /// template-argument-list ',' template-argument bool Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) { // Template argument lists are constant-evaluation contexts. EnterExpressionEvaluationContext EvalContext(Actions,Sema::ConstantEvaluated); ColonProtectionRAIIObject ColonProtection(*this, false); do { ParsedTemplateArgument Arg = ParseTemplateArgument(); SourceLocation EllipsisLoc; if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc); if (Arg.isInvalid()) { SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch); return true; } // Save this template argument. TemplateArgs.push_back(Arg); // If the next token is a comma, consume it and keep reading // arguments. } while (TryConsumeToken(tok::comma)); return false; } /// \brief Parse a C++ explicit template instantiation /// (C++ [temp.explicit]). /// /// explicit-instantiation: /// 'extern' [opt] 'template' declaration /// /// Note that the 'extern' is a GNU extension and C++11 feature. Decl *Parser::ParseExplicitInstantiation(unsigned Context, SourceLocation ExternLoc, SourceLocation TemplateLoc, SourceLocation &DeclEnd, AccessSpecifier AS) { // This isn't really required here. ParsingDeclRAIIObject ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent); return ParseSingleDeclarationAfterTemplate(Context, ParsedTemplateInfo(ExternLoc, TemplateLoc), ParsingTemplateParams, DeclEnd, AS); } SourceRange Parser::ParsedTemplateInfo::getSourceRange() const { if (TemplateParams) return getTemplateParamsRange(TemplateParams->data(), TemplateParams->size()); SourceRange R(TemplateLoc); if (ExternLoc.isValid()) R.setBegin(ExternLoc); return R; } void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) { ((Parser *)P)->ParseLateTemplatedFuncDef(LPT); } /// \brief Late parse a C++ function template in Microsoft mode. void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) { if (!LPT.D) return; // Get the FunctionDecl. FunctionDecl *FunD = LPT.D->getAsFunction(); // Track template parameter depth. TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth); // To restore the context after late parsing. Sema::ContextRAII GlobalSavedContext(Actions, Actions.CurContext); SmallVector<ParseScope*, 4> TemplateParamScopeStack; // Get the list of DeclContexts to reenter. SmallVector<DeclContext*, 4> DeclContextsToReenter; DeclContext *DD = FunD; while (DD && !DD->isTranslationUnit()) { DeclContextsToReenter.push_back(DD); DD = DD->getLexicalParent(); } // Reenter template scopes from outermost to innermost. SmallVectorImpl<DeclContext *>::reverse_iterator II = DeclContextsToReenter.rbegin(); for (; II != DeclContextsToReenter.rend(); ++II) { TemplateParamScopeStack.push_back(new ParseScope(this, Scope::TemplateParamScope)); unsigned NumParamLists = Actions.ActOnReenterTemplateScope(getCurScope(), cast<Decl>(*II)); CurTemplateDepthTracker.addDepth(NumParamLists); if (*II != FunD) { TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope)); Actions.PushDeclContext(Actions.getCurScope(), *II); } } assert(!LPT.Toks.empty() && "Empty body!"); // Append the current token at the end of the new token stream so that it // doesn't get lost. LPT.Toks.push_back(Tok); PP.EnterTokenStream(LPT.Toks.data(), LPT.Toks.size(), true, false); // Consume the previously pushed token. ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true); assert((Tok.is(tok::l_brace) || Tok.is(tok::colon) || Tok.is(tok::kw_try)) && "Inline method not starting with '{', ':' or 'try'"); // Parse the method body. Function body parsing code is similar enough // to be re-used for method bodies as well. ParseScope FnScope(this, Scope::FnScope|Scope::DeclScope); // Recreate the containing function DeclContext. Sema::ContextRAII FunctionSavedContext(Actions, Actions.getContainingDC(FunD)); Actions.ActOnStartOfFunctionDef(getCurScope(), FunD); if (Tok.is(tok::kw_try)) { ParseFunctionTryBlock(LPT.D, FnScope); } else { if (Tok.is(tok::colon)) ParseConstructorInitializer(LPT.D); else Actions.ActOnDefaultCtorInitializers(LPT.D); if (Tok.is(tok::l_brace)) { assert((!isa<FunctionTemplateDecl>(LPT.D) || cast<FunctionTemplateDecl>(LPT.D) ->getTemplateParameters() ->getDepth() == TemplateParameterDepth - 1) && "TemplateParameterDepth should be greater than the depth of " "current template being instantiated!"); ParseFunctionStatementBody(LPT.D, FnScope); Actions.UnmarkAsLateParsedTemplate(FunD); } else Actions.ActOnFinishFunctionBody(LPT.D, nullptr); } // Exit scopes. FnScope.Exit(); SmallVectorImpl<ParseScope *>::reverse_iterator I = TemplateParamScopeStack.rbegin(); for (; I != TemplateParamScopeStack.rend(); ++I) delete *I; } /// \brief Lex a delayed template function for late parsing. void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) { tok::TokenKind kind = Tok.getKind(); if (!ConsumeAndStoreFunctionPrologue(Toks)) { // Consume everything up to (and including) the matching right brace. ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false); } // If we're in a function-try-block, we need to store all the catch blocks. if (kind == tok::kw_try) { while (Tok.is(tok::kw_catch)) { ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false); ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false); } } }