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llvm-project/clang/lib/Parse/ParseTemplate.cpp

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//===--- 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/Sema/DeclSpec.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
#include "RAIIObjectsForParser.h"
using namespace clang;
/// \brief Parse a template declaration, explicit instantiation, or
/// explicit specialization.
Decl *
Parser::ParseDeclarationStartingWithTemplate(unsigned Context,
SourceLocation &DeclEnd,
AccessSpecifier AS) {
if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less))
return ParseExplicitInstantiation(SourceLocation(), ConsumeToken(),
DeclEnd);
return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS);
}
/// \brief RAII class that manages the template parameter depth.
namespace {
class TemplateParameterDepthCounter {
unsigned &Depth;
unsigned AddedLevels;
public:
explicit TemplateParameterDepthCounter(unsigned &Depth)
: Depth(Depth), AddedLevels(0) { }
~TemplateParameterDepthCounter() {
Depth -= AddedLevels;
}
void operator++() {
++Depth;
++AddedLevels;
}
operator unsigned() const { return Depth; }
};
}
/// \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) {
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);
// 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;
TemplateParameterDepthCounter Depth(TemplateParameterDepth);
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;
llvm::SmallVector<Decl*, 4> TemplateParams;
if (ParseTemplateParameters(Depth, TemplateParams, LAngleLoc,
RAngleLoc)) {
// Skip until the semi-colon or a }.
SkipUntil(tok::r_brace, true, true);
if (Tok.is(tok::semi))
ConsumeToken();
return 0;
}
ParamLists.push_back(
Actions.ActOnTemplateParameterList(Depth, ExportLoc,
TemplateLoc, LAngleLoc,
TemplateParams.data(),
TemplateParams.size(), RAngleLoc));
if (!TemplateParams.empty()) {
isSpecialization = false;
++Depth;
} 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);
}
/// \brief Parse a single declaration that declares a template,
/// template specialization, or explicit instantiation of a template.
///
/// \param TemplateParams if non-NULL, the template parameter lists
/// that preceded this declaration. In this case, the declaration is a
/// template declaration, out-of-line definition of a template, or an
/// explicit template specialization. When NULL, the declaration is an
/// explicit template instantiation.
///
/// \param TemplateLoc when TemplateParams is NULL, the location of
/// the 'template' keyword that indicates that we have an explicit
/// template instantiation.
///
/// \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) {
assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
"Template information required");
if (Context == Declarator::MemberContext) {
// We are parsing a member template.
ParseCXXClassMemberDeclaration(AS, TemplateInfo, &DiagsFromTParams);
return 0;
}
ParsedAttributesWithRange prefixAttrs;
MaybeParseCXX0XAttributes(prefixAttrs);
if (Tok.is(tok::kw_using))
return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
prefixAttrs);
// Parse the declaration specifiers, stealing the accumulated
// diagnostics from the template parameters.
ParsingDeclSpec DS(DiagsFromTParams);
DS.takeAttributesFrom(prefixAttrs);
ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
getDeclSpecContextFromDeclaratorContext(Context));
if (Tok.is(tok::semi)) {
DeclEnd = ConsumeToken();
Decl *Decl = Actions.ParsedFreeStandingDeclSpec(getCurScope(), AS, DS);
DS.complete(Decl);
return Decl;
}
// 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, true, true);
if (Tok.is(tok::semi))
ConsumeToken();
return 0;
}
// If we have a declaration or declarator list, handle it.
if (isDeclarationAfterDeclarator()) {
// 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, true, false);
return ThisDecl;
}
// Eat the semi colon after the declaration.
ExpectAndConsume(tok::semi, diag::err_expected_semi_declaration);
DS.complete(ThisDecl);
return ThisDecl;
}
if (DeclaratorInfo.isFunctionDeclarator() &&
isStartOfFunctionDefinition(DeclaratorInfo)) {
if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
Diag(Tok, diag::err_function_declared_typedef);
if (Tok.is(tok::l_brace)) {
// This recovery skips the entire function body. It would be nice
// to simply call ParseFunctionDefinition() below, however Sema
// assumes the declarator represents a function, not a typedef.
ConsumeBrace();
SkipUntil(tok::r_brace, true);
} else {
SkipUntil(tok::semi);
}
return 0;
}
return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo);
}
if (DeclaratorInfo.isFunctionDeclarator())
Diag(Tok, diag::err_expected_fn_body);
else
Diag(Tok, diag::err_invalid_token_after_toplevel_declarator);
SkipUntil(tok::semi);
return 0;
}
/// 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,
llvm::SmallVectorImpl<Decl*> &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 true;
}
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 true;
}
RAngleLoc = ConsumeToken();
}
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,
llvm::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, 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;
}
/// \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).
bool Ellipsis = false;
SourceLocation EllipsisLoc;
if (Tok.is(tok::ellipsis)) {
Ellipsis = true;
EllipsisLoc = ConsumeToken();
if (!getLang().CPlusPlus0x)
Diag(EllipsisLoc, diag::ext_variadic_templates);
}
// 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;
}
// 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 (Tok.is(tok::equal)) {
EqualLoc = ConsumeToken();
DefaultArg = ParseTypeName().get();
}
return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, Ellipsis,
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 '>' 'class'
/// ...[opt] identifier[opt]
/// 'template' '<' template-parameter-list '>' 'class' identifier[opt]
/// = id-expression
Decl *
Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
// Handle the template <...> part.
SourceLocation TemplateLoc = ConsumeToken();
llvm::SmallVector<Decl*,8> 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;
}
ConsumeToken();
// Parse the ellipsis, if given.
SourceLocation EllipsisLoc;
if (Tok.is(tok::ellipsis)) {
EllipsisLoc = ConsumeToken();
if (!getLang().CPlusPlus0x)
Diag(EllipsisLoc, diag::ext_variadic_templates);
}
// 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.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 (Tok.is(tok::equal)) {
EqualLoc = ConsumeToken();
DefaultArg = ParseTemplateTemplateArgument();
if (DefaultArg.isInvalid()) {
Diag(Tok.getLocation(),
diag::err_default_template_template_parameter_not_template);
static const tok::TokenKind EndToks[] = {
tok::comma, tok::greater, tok::greatergreater
};
SkipUntil(EndToks, 3, true, true);
}
}
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;
ParseDeclarationSpecifiers(DS);
// Parse this as a typename.
Declarator ParamDecl(DS, Declarator::TemplateParamContext);
ParseDeclarator(ParamDecl);
if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
// 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;
}
// 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 (Tok.is(tok::equal)) {
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);
DefaultArg = ParseAssignmentExpression();
if (DefaultArg.isInvalid())
SkipUntil(tok::comma, tok::greater, true, true);
}
// Create the parameter.
return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl,
Depth, Position, EqualLoc,
DefaultArg.take());
}
/// \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 '>'.
SkipUntil(tok::greater, true, !ConsumeLastToken);
return true;
}
}
if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater)) {
Diag(Tok.getLocation(), diag::err_expected_greater);
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)
<< FixItHint::CreateReplacement(
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.
///
/// If an unrecoverable parse error occurs and no annotation token can be
/// formed, this function returns true.
///
bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
const CXXScopeSpec *SS,
UnqualifiedId &TemplateName,
SourceLocation TemplateKWLoc,
bool AllowTypeAnnotation) {
assert(getLang().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.
if (Tok.is(tok::greater))
ConsumeToken();
return true;
}
ASTTemplateArgsPtr TemplateArgsPtr(Actions, TemplateArgs.data(),
TemplateArgs.size());
// Build the annotation token.
if (TNK == TNK_Type_template && AllowTypeAnnotation) {
TypeResult Type
= Actions.ActOnTemplateIdType(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.
if (Tok.is(tok::greater))
ConsumeToken();
return true;
}
Tok.setKind(tok::annot_typename);
setTypeAnnotation(Tok, Type.get());
if (SS && 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());
TemplateId->TemplateNameLoc = TemplateNameLoc;
if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) {
TemplateId->Name = TemplateName.Identifier;
TemplateId->Operator = OO_None;
} else {
TemplateId->Name = 0;
TemplateId->Operator = TemplateName.OperatorFunctionId.Operator;
}
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] = TemplateArgs[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);
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(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_Type_template ||
TemplateId->Kind == TNK_Dependent_template_name) &&
"Only works for type and dependent templates");
ASTTemplateArgsPtr TemplateArgsPtr(Actions,
TemplateId->getTemplateArgs(),
TemplateId->NumArgs);
TypeResult Type
= Actions.ActOnTemplateIdType(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 (SS && SS->isNotEmpty()) // it was a C++ qualified type name.
Tok.setLocation(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);
TemplateId->Destroy();
}
/// \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 a template alias, expressed as id-expression.
//
// We parse an id-expression that refers to a class template or template
// alias. 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 TemplateLoc = 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
// Parse the ellipsis.
if (Tok.is(tok::ellipsis))
EllipsisLoc = ConsumeToken();
// 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(), TemplateLoc,
SS, 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
// Parse the ellipsis.
if (Tok.is(tok::ellipsis))
EllipsisLoc = ConsumeToken();
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) template alias.
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();
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();
if (ExprArg.isInvalid() || !ExprArg.get())
return ParsedTemplateArgument();
return ParsedTemplateArgument(ParsedTemplateArgument::NonType,
ExprArg.release(), 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 (!Tok.is(tok::less))
return false;
ConsumeToken();
// 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) {
while (true) {
ParsedTemplateArgument Arg = ParseTemplateArgument();
if (Tok.is(tok::ellipsis)) {
SourceLocation EllipsisLoc = ConsumeToken();
Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
}
if (Arg.isInvalid()) {
SkipUntil(tok::comma, tok::greater, true, true);
return true;
}
// Save this template argument.
TemplateArgs.push_back(Arg);
// If the next token is a comma, consume it and keep reading
// arguments.
if (Tok.isNot(tok::comma)) break;
// Consume the comma.
ConsumeToken();
}
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++0x feature.
Decl *Parser::ParseExplicitInstantiation(SourceLocation ExternLoc,
SourceLocation TemplateLoc,
SourceLocation &DeclEnd) {
// This isn't really required here.
ParsingDeclRAIIObject ParsingTemplateParams(*this);
return ParseSingleDeclarationAfterTemplate(Declarator::FileContext,
ParsedTemplateInfo(ExternLoc,
TemplateLoc),
ParsingTemplateParams,
DeclEnd, AS_none);
}
SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
if (TemplateParams)
return getTemplateParamsRange(TemplateParams->data(),
TemplateParams->size());
SourceRange R(TemplateLoc);
if (ExternLoc.isValid())
R.setBegin(ExternLoc);
return R;
}
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