blob: 0209d7b0ab590948f739c296ec9a7017994094cb [file] [log] [blame]
//===--- 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) && Tok.isNot(tok::greatergreater))
return true;
// Determine the location of the '>' or '>>'. Only consume this
// token if the caller asked us to.
RAngleLoc = Tok.getLocation();
if (Tok.is(tok::greatergreater)) {
if (!getLang().CPlusPlus0x) {
const char *ReplaceStr = "> >";
if (NextToken().is(tok::greater) || NextToken().is(tok::greatergreater))
ReplaceStr = "> > ";
Diag(Tok.getLocation(), diag::err_two_right_angle_brackets_need_space)
<< CodeReplacementHint(SourceRange(Tok.getLocation()), ReplaceStr);
}
Tok.setKind(tok::greater);
if (!ConsumeLastToken) {
// Since we're not supposed to consume the '>>' token, we need
// to insert a second '>' token after the first.
PP.EnterToken(Tok);
}
} else if (ConsumeLastToken)
ConsumeToken();
return false;
}
/// \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 TemplateNameKind 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.
void Parser::AnnotateTemplateIdToken(DeclTy *Template, TemplateNameKind TNK,
const CXXScopeSpec *SS,
SourceLocation TemplateKWLoc,
bool AllowTypeAnnotation) {
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.
IdentifierInfo *Name = Tok.getIdentifierInfo();
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 == TNK_Class_template && AllowTypeAnnotation) {
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());
if (SS && SS->isNotEmpty())
Tok.setLocation(SS->getBeginLoc());
else if (TemplateKWLoc.isValid())
Tok.setLocation(TemplateKWLoc);
else
Tok.setLocation(TemplateNameLoc);
} else {
// This is a function template. We'll be building a template-id
// annotation token.
Tok.setKind(tok::annot_template_id);
TemplateIdAnnotation *TemplateId
= TemplateIdAnnotation::Allocate(TemplateArgs.size());
TemplateId->TemplateNameLoc = TemplateNameLoc;
TemplateId->Name = Name;
TemplateId->Template = Template;
TemplateId->Kind = TNK;
TemplateId->LAngleLoc = LAngleLoc;
TemplateId->RAngleLoc = RAngleLoc;
void **Args = TemplateId->getTemplateArgs();
bool *ArgIsType = TemplateId->getTemplateArgIsType();
SourceLocation *ArgLocs = TemplateId->getTemplateArgLocations();
for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg) {
Args[Arg] = TemplateArgs[Arg];
ArgIsType[Arg] = TemplateArgIsType[Arg];
ArgLocs[Arg] = TemplateArgLocations[Arg];
}
Tok.setAnnotationValue(TemplateId);
if (TemplateKWLoc.isValid())
Tok.setLocation(TemplateKWLoc);
else
Tok.setLocation(TemplateNameLoc);
TemplateArgsPtr.release();
}
// 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);
}
/// \brief Replaces a template-id annotation token with a type
/// annotation token.
///
/// \returns true if there was an error, false otherwise.
bool Parser::AnnotateTemplateIdTokenAsType(const CXXScopeSpec *SS) {
assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
TemplateIdAnnotation *TemplateId
= static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
assert(TemplateId->Kind == TNK_Class_template &&
"Only works for class templates");
ASTTemplateArgsPtr TemplateArgsPtr(Actions,
TemplateId->getTemplateArgs(),
TemplateId->getTemplateArgIsType(),
TemplateId->NumArgs);
Action::TypeResult Type
= Actions.ActOnClassTemplateId(TemplateId->Template,
TemplateId->TemplateNameLoc,
TemplateId->LAngleLoc,
TemplateArgsPtr,
TemplateId->getTemplateArgLocations(),
TemplateId->RAngleLoc, SS);
if (Type.isInvalid()) {
// FIXME: better recovery?
ConsumeToken();
TemplateId->Destroy();
return true;
}
// Create the new "type" annotation token.
Tok.setKind(tok::annot_typename);
Tok.setAnnotationValue(Type.get());
if (SS && SS->isNotEmpty()) // it was a C++ qualified type name.
Tok.setLocation(SS->getBeginLoc());
// We might be backtracking, in which case we need to replace the
// template-id annotation token with the type annotation within the
// set of cached tokens. That way, we won't try to form the same
// class template specialization again.
PP.ReplaceLastTokenWithAnnotation(Tok);
TemplateId->Destroy();
return false;
}
/// 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) && Tok.isNot(tok::greatergreater);
}