| //===--- 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 "clang/Parse/ParseDiagnostic.h" |
| #include "clang/Parse/DeclSpec.h" |
| #include "clang/Parse/Scope.h" |
| #include "AstGuard.h" |
| |
| using namespace clang; |
| |
| /// \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 |
| Parser::DeclTy * |
| Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context) { |
| 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); |
| |
| // 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). |
| TemplateParameterLists ParamLists; |
| do { |
| // Consume the 'export', if any. |
| SourceLocation ExportLoc; |
| if (Tok.is(tok::kw_export)) { |
| ExportLoc = ConsumeToken(); |
| } |
| |
| // Consume the 'template', which should be here. |
| SourceLocation TemplateLoc; |
| if (Tok.is(tok::kw_template)) { |
| TemplateLoc = ConsumeToken(); |
| } else { |
| Diag(Tok.getLocation(), diag::err_expected_template); |
| return 0; |
| } |
| |
| // Parse the '<' template-parameter-list '>' |
| SourceLocation LAngleLoc, RAngleLoc; |
| TemplateParameterList TemplateParams; |
| ParseTemplateParameters(ParamLists.size(), TemplateParams, LAngleLoc, |
| RAngleLoc); |
| |
| ParamLists.push_back( |
| Actions.ActOnTemplateParameterList(ParamLists.size(), ExportLoc, |
| TemplateLoc, LAngleLoc, |
| &TemplateParams[0], |
| TemplateParams.size(), RAngleLoc)); |
| } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template)); |
| |
| // Parse the actual template declaration. |
| return ParseDeclarationOrFunctionDefinition(&ParamLists); |
| } |
| |
| /// 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. |
| bool Parser::ParseTemplateParameters(unsigned Depth, |
| TemplateParameterList &TemplateParams, |
| SourceLocation &LAngleLoc, |
| SourceLocation &RAngleLoc) { |
| // Get the template parameter list. |
| if(!Tok.is(tok::less)) { |
| Diag(Tok.getLocation(), diag::err_expected_less_after) << "template"; |
| return false; |
| } |
| LAngleLoc = ConsumeToken(); |
| |
| // Try to parse the template parameter list. |
| if (Tok.is(tok::greater)) |
| RAngleLoc = ConsumeToken(); |
| else if(ParseTemplateParameterList(Depth, TemplateParams)) { |
| if(!Tok.is(tok::greater)) { |
| Diag(Tok.getLocation(), diag::err_expected_greater); |
| return false; |
| } |
| RAngleLoc = ConsumeToken(); |
| } |
| return true; |
| } |
| |
| /// 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, |
| TemplateParameterList &TemplateParams) { |
| while(1) { |
| if (DeclTy* 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, true, true); |
| } |
| |
| // Did we find a comma or the end of the template parmeter list? |
| if(Tok.is(tok::comma)) { |
| ConsumeToken(); |
| } else if(Tok.is(tok::greater)) { |
| // 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. |
| // TODO: This could match >>, and it would be nice to avoid those |
| // silly errors with template <vec<T>>. |
| // Diag(Tok.getLocation(), diag::err_expected_comma_greater); |
| SkipUntil(tok::greater, true, true); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]). |
| /// |
| /// template-parameter: [C++ temp.param] |
| /// type-parameter |
| /// parameter-declaration |
| /// |
| /// type-parameter: (see below) |
| /// 'class' identifier[opt] |
| /// 'class' identifier[opt] '=' type-id |
| /// 'typename' identifier[opt] |
| /// 'typename' identifier[opt] '=' type-id |
| /// 'template' '<' template-parameter-list '>' 'class' identifier[opt] |
| /// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression |
| Parser::DeclTy * |
| Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) { |
| if(Tok.is(tok::kw_class) || |
| (Tok.is(tok::kw_typename) && |
| // FIXME: Next token has not been annotated! |
| NextToken().isNot(tok::annot_typename))) { |
| 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' identifier[opt] |
| /// 'class' identifier[opt] '=' type-id |
| /// 'typename' identifier[opt] |
| /// 'typename' identifier[opt] '=' type-id |
| Parser::DeclTy *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 template parameter name (if given) |
| SourceLocation NameLoc; |
| IdentifierInfo* ParamName = 0; |
| if(Tok.is(tok::identifier)) { |
| ParamName = Tok.getIdentifierInfo(); |
| NameLoc = ConsumeToken(); |
| } else if(Tok.is(tok::equal) || Tok.is(tok::comma) || |
| Tok.is(tok::greater)) { |
| // Unnamed template parameter. Don't have to do anything here, just |
| // don't consume this token. |
| } else { |
| Diag(Tok.getLocation(), diag::err_expected_ident); |
| return 0; |
| } |
| |
| DeclTy *TypeParam = Actions.ActOnTypeParameter(CurScope, TypenameKeyword, |
| KeyLoc, ParamName, NameLoc, |
| Depth, Position); |
| |
| // Grab a default type id (if given). |
| if(Tok.is(tok::equal)) { |
| SourceLocation EqualLoc = ConsumeToken(); |
| SourceLocation DefaultLoc = Tok.getLocation(); |
| TypeResult DefaultType = ParseTypeName(); |
| if (!DefaultType.isInvalid()) |
| Actions.ActOnTypeParameterDefault(TypeParam, EqualLoc, DefaultLoc, |
| DefaultType.get()); |
| } |
| |
| return TypeParam; |
| } |
| |
| /// ParseTemplateTemplateParameter - Handle the parsing of template |
| /// template parameters. |
| /// |
| /// type-parameter: [C++ temp.param] |
| /// 'template' '<' template-parameter-list '>' 'class' identifier[opt] |
| /// 'template' '<' template-parameter-list '>' 'class' identifier[opt] = id-expression |
| Parser::DeclTy * |
| Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) { |
| assert(Tok.is(tok::kw_template) && "Expected 'template' keyword"); |
| |
| // Handle the template <...> part. |
| SourceLocation TemplateLoc = ConsumeToken(); |
| TemplateParameterList TemplateParams; |
| SourceLocation LAngleLoc, RAngleLoc; |
| { |
| ParseScope TemplateParmScope(this, Scope::TemplateParamScope); |
| if(!ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc, |
| RAngleLoc)) { |
| return 0; |
| } |
| } |
| |
| // Generate a meaningful error if the user forgot to put class before the |
| // identifier, comma, or greater. |
| if(!Tok.is(tok::kw_class)) { |
| Diag(Tok.getLocation(), diag::err_expected_class_before) |
| << PP.getSpelling(Tok); |
| return 0; |
| } |
| SourceLocation ClassLoc = ConsumeToken(); |
| |
| // Get the identifier, if given. |
| SourceLocation NameLoc; |
| IdentifierInfo* ParamName = 0; |
| if(Tok.is(tok::identifier)) { |
| ParamName = Tok.getIdentifierInfo(); |
| NameLoc = ConsumeToken(); |
| } else if(Tok.is(tok::equal) || Tok.is(tok::comma) || Tok.is(tok::greater)) { |
| // Unnamed template parameter. Don't have to do anything here, just |
| // don't consume this token. |
| } else { |
| Diag(Tok.getLocation(), diag::err_expected_ident); |
| return 0; |
| } |
| |
| TemplateParamsTy *ParamList = |
| Actions.ActOnTemplateParameterList(Depth, SourceLocation(), |
| TemplateLoc, LAngleLoc, |
| &TemplateParams[0], |
| TemplateParams.size(), |
| RAngleLoc); |
| |
| Parser::DeclTy * Param |
| = Actions.ActOnTemplateTemplateParameter(CurScope, TemplateLoc, |
| ParamList, ParamName, |
| NameLoc, Depth, Position); |
| |
| // Get the a default value, if given. |
| if (Tok.is(tok::equal)) { |
| SourceLocation EqualLoc = ConsumeToken(); |
| OwningExprResult DefaultExpr = ParseCXXIdExpression(); |
| if (DefaultExpr.isInvalid()) |
| return Param; |
| else if (Param) |
| Actions.ActOnTemplateTemplateParameterDefault(Param, EqualLoc, |
| move(DefaultExpr)); |
| } |
| |
| return Param; |
| } |
| |
| /// ParseNonTypeTemplateParameter - Handle the parsing of non-type |
| /// template parameters (e.g., in "template<int Size> class array;"). |
| /// |
| /// template-parameter: |
| /// ... |
| /// parameter-declaration |
| /// |
| /// NOTE: It would be ideal to simply call out to ParseParameterDeclaration(), |
| /// but that didn't work out to well. Instead, this tries to recrate the basic |
| /// parsing of parameter declarations, but tries to constrain it for template |
| /// parameters. |
| /// FIXME: We need to make a ParseParameterDeclaration that works for |
| /// non-type template parameters and normal function parameters. |
| Parser::DeclTy * |
| Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) { |
| SourceLocation StartLoc = Tok.getLocation(); |
| |
| // 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; |
| ParseDeclarationSpecifiers(DS); |
| |
| // Parse this as a typename. |
| Declarator ParamDecl(DS, Declarator::TemplateParamContext); |
| ParseDeclarator(ParamDecl); |
| if (DS.getTypeSpecType() == DeclSpec::TST_unspecified && !DS.getTypeRep()) { |
| // This probably shouldn't happen - and it's more of a Sema thing, but |
| // basically we didn't parse the type name because we couldn't associate |
| // it with an AST node. we should just skip to the comma or greater. |
| // TODO: This is currently a placeholder for some kind of Sema Error. |
| Diag(Tok.getLocation(), diag::err_parse_error); |
| SkipUntil(tok::comma, tok::greater, true, true); |
| return 0; |
| } |
| |
| // Create the parameter. |
| DeclTy *Param = Actions.ActOnNonTypeTemplateParameter(CurScope, ParamDecl, |
| Depth, Position); |
| |
| // If there is a default value, parse it. |
| if (Tok.is(tok::equal)) { |
| SourceLocation EqualLoc = ConsumeToken(); |
| |
| // 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); |
| |
| OwningExprResult DefaultArg = ParseAssignmentExpression(); |
| if (DefaultArg.isInvalid()) |
| SkipUntil(tok::comma, tok::greater, true, true); |
| else if (Param) |
| Actions.ActOnNonTypeTemplateParameterDefault(Param, EqualLoc, |
| move(DefaultArg)); |
| } |
| |
| return Param; |
| } |
| |
| /// \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(DeclTy *Template, |
| SourceLocation TemplateNameLoc, |
| const CXXScopeSpec *SS, |
| bool ConsumeLastToken, |
| SourceLocation &LAngleLoc, |
| TemplateArgList &TemplateArgs, |
| TemplateArgIsTypeList &TemplateArgIsType, |
| TemplateArgLocationList &TemplateArgLocations, |
| 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)) |
| Invalid = ParseTemplateArgumentList(TemplateArgs, TemplateArgIsType, |
| TemplateArgLocations); |
| |
| if (Invalid) { |
| // Try to find the closing '>'. |
| SkipUntil(tok::greater, true, !ConsumeLastToken); |
| |
| return true; |
| } |
| } |
| |
| if (Tok.isNot(tok::greater)) |
| return true; |
| |
| // Determine the location of the '>'. Only consume this token if the |
| // caller asked us to. |
| RAngleLoc = Tok.getLocation(); |
| |
| if (ConsumeLastToken) |
| ConsumeToken(); |
| |
| return false; |
| } |
| |
| /// AnnotateTemplateIdToken - The current token is an identifier that |
| /// refers to the template declaration Template, and is followed by a |
| /// '<'. Turn this template-id into a template-id annotation token. |
| void Parser::AnnotateTemplateIdToken(DeclTy *Template, TemplateNameKind TNK, |
| const CXXScopeSpec *SS) { |
| assert(getLang().CPlusPlus && "Can only annotate template-ids in C++"); |
| assert(Template && Tok.is(tok::identifier) && NextToken().is(tok::less) && |
| "Parser isn't at the beginning of a template-id"); |
| |
| // Consume the template-name. |
| SourceLocation TemplateNameLoc = ConsumeToken(); |
| |
| // Parse the enclosed template argument list. |
| SourceLocation LAngleLoc, RAngleLoc; |
| TemplateArgList TemplateArgs; |
| TemplateArgIsTypeList TemplateArgIsType; |
| TemplateArgLocationList TemplateArgLocations; |
| bool Invalid = ParseTemplateIdAfterTemplateName(Template, TemplateNameLoc, |
| SS, false, LAngleLoc, |
| TemplateArgs, |
| TemplateArgIsType, |
| TemplateArgLocations, |
| RAngleLoc); |
| |
| ASTTemplateArgsPtr TemplateArgsPtr(Actions, &TemplateArgs[0], |
| &TemplateArgIsType[0], |
| TemplateArgs.size()); |
| |
| if (Invalid) // FIXME: How to recover from a broken template-id? |
| return; |
| |
| // Build the annotation token. |
| if (TNK == Action::TNK_Class_template) { |
| Action::TypeResult Type |
| = Actions.ActOnClassTemplateId(Template, TemplateNameLoc, |
| LAngleLoc, TemplateArgsPtr, |
| &TemplateArgLocations[0], |
| RAngleLoc, SS); |
| if (Type.isInvalid()) // FIXME: better recovery? |
| return; |
| |
| Tok.setKind(tok::annot_typename); |
| Tok.setAnnotationValue(Type.get()); |
| } else { |
| // This is a function template. We'll be building a template-id |
| // annotation token. |
| Tok.setKind(tok::annot_template_id); |
| TemplateIdAnnotation *TemplateId |
| = (TemplateIdAnnotation *)malloc(sizeof(TemplateIdAnnotation) + |
| sizeof(void*) * TemplateArgs.size()); |
| TemplateId->TemplateNameLoc = TemplateNameLoc; |
| TemplateId->Template = Template; |
| TemplateId->LAngleLoc = LAngleLoc; |
| TemplateId->NumArgs = TemplateArgs.size(); |
| void **Args = (void**)(TemplateId + 1); |
| for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) |
| Args[Arg] = TemplateArgs[Arg]; |
| Tok.setAnnotationValue(TemplateId); |
| } |
| |
| // Common fields for the annotation token |
| Tok.setAnnotationEndLoc(RAngleLoc); |
| Tok.setLocation(TemplateNameLoc); |
| if (SS && SS->isNotEmpty()) |
| Tok.setLocation(SS->getBeginLoc()); |
| |
| // In case the tokens were cached, have Preprocessor replace them with the |
| // annotation token. |
| PP.AnnotateCachedTokens(Tok); |
| } |
| |
| /// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]). |
| /// |
| /// template-argument: [C++ 14.2] |
| /// assignment-expression |
| /// type-id |
| /// id-expression |
| void *Parser::ParseTemplateArgument(bool &ArgIsType) { |
| // 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)) { |
| ArgIsType = true; |
| TypeResult TypeArg = ParseTypeName(); |
| if (TypeArg.isInvalid()) |
| return 0; |
| return TypeArg.get(); |
| } |
| |
| OwningExprResult ExprArg = ParseAssignmentExpression(); |
| if (ExprArg.isInvalid() || !ExprArg.get()) |
| return 0; |
| |
| ArgIsType = false; |
| return ExprArg.release(); |
| } |
| |
| /// 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, |
| TemplateArgIsTypeList &TemplateArgIsType, |
| TemplateArgLocationList &TemplateArgLocations) { |
| while (true) { |
| bool IsType = false; |
| SourceLocation Loc = Tok.getLocation(); |
| void *Arg = ParseTemplateArgument(IsType); |
| if (Arg) { |
| TemplateArgs.push_back(Arg); |
| TemplateArgIsType.push_back(IsType); |
| TemplateArgLocations.push_back(Loc); |
| } else { |
| SkipUntil(tok::comma, tok::greater, true, true); |
| return true; |
| } |
| |
| // If the next token is a comma, consume it and keep reading |
| // arguments. |
| if (Tok.isNot(tok::comma)) break; |
| |
| // Consume the comma. |
| ConsumeToken(); |
| } |
| |
| return Tok.isNot(tok::greater); |
| } |
| |