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llvm-project/clang/lib/Sema/SemaTemplate.cpp

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//===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===/
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//+//===----------------------------------------------------------------------===/
//
// This file implements semantic analysis for C++ templates.
//+//===----------------------------------------------------------------------===/
#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Expr.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Basic/LangOptions.h"
using namespace clang;
/// isTemplateName - Determines whether the identifier II is a
/// template name in the current scope, and returns the template
/// declaration if II names a template. An optional CXXScope can be
/// passed to indicate the C++ scope in which the identifier will be
/// found.
Sema::DeclTy *Sema::isTemplateName(IdentifierInfo &II, Scope *S,
const CXXScopeSpec *SS) {
DeclContext *DC = 0;
if (SS) {
if (SS->isInvalid())
return 0;
DC = static_cast<DeclContext*>(SS->getScopeRep());
}
NamedDecl *IIDecl = LookupParsedName(S, SS, &II, LookupOrdinaryName);
if (IIDecl) {
// FIXME: We need to represent templates via some kind of
// TemplateDecl, because what follows is a hack that only works in
// one specific case.
if (isa<TemplateDecl>(IIDecl))
return IIDecl;
if (FunctionDecl *FD = dyn_cast<FunctionDecl>(IIDecl)) {
if (FD->getType()->isDependentType())
return FD;
} else if (OverloadedFunctionDecl *Ovl
= dyn_cast<OverloadedFunctionDecl>(IIDecl)) {
for (OverloadedFunctionDecl::function_iterator F = Ovl->function_begin(),
FEnd = Ovl->function_end();
F != FEnd; ++F) {
if ((*F)->getType()->isDependentType())
return Ovl;
}
}
}
return 0;
}
/// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
/// that the template parameter 'PrevDecl' is being shadowed by a new
/// declaration at location Loc. Returns true to indicate that this is
/// an error, and false otherwise.
bool Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
// Microsoft Visual C++ permits template parameters to be shadowed.
if (getLangOptions().Microsoft)
return false;
// C++ [temp.local]p4:
// A template-parameter shall not be redeclared within its
// scope (including nested scopes).
Diag(Loc, diag::err_template_param_shadow)
<< cast<NamedDecl>(PrevDecl)->getDeclName();
Diag(PrevDecl->getLocation(), diag::note_template_param_here);
return true;
}
/// AdjustDeclForTemplates - If the given decl happens to be a template, reset
/// the parameter D to reference the templated declaration and return a pointer
/// to the template declaration. Otherwise, do nothing to D and return null.
TemplateDecl *Sema::AdjustDeclIfTemplate(DeclTy *&D)
{
if(TemplateDecl *Temp = dyn_cast<TemplateDecl>(static_cast<Decl*>(D))) {
D = Temp->getTemplatedDecl();
return Temp;
}
return 0;
}
/// ActOnTypeParameter - Called when a C++ template type parameter
/// (e.g., "typename T") has been parsed. Typename specifies whether
/// the keyword "typename" was used to declare the type parameter
/// (otherwise, "class" was used), and KeyLoc is the location of the
/// "class" or "typename" keyword. ParamName is the name of the
/// parameter (NULL indicates an unnamed template parameter) and
/// ParamName is the location of the parameter name (if any).
/// If the type parameter has a default argument, it will be added
/// later via ActOnTypeParameterDefault.
Sema::DeclTy *Sema::ActOnTypeParameter(Scope *S, bool Typename,
SourceLocation KeyLoc,
IdentifierInfo *ParamName,
SourceLocation ParamNameLoc,
unsigned Depth, unsigned Position) {
assert(S->isTemplateParamScope() &&
"Template type parameter not in template parameter scope!");
bool Invalid = false;
if (ParamName) {
NamedDecl *PrevDecl = LookupName(S, ParamName, LookupTagName);
if (PrevDecl && PrevDecl->isTemplateParameter())
Invalid = Invalid || DiagnoseTemplateParameterShadow(ParamNameLoc,
PrevDecl);
}
SourceLocation Loc = ParamNameLoc;
if (!ParamName)
Loc = KeyLoc;
TemplateTypeParmDecl *Param
= TemplateTypeParmDecl::Create(Context, CurContext, Loc,
Depth, Position, ParamName, Typename);
if (Invalid)
Param->setInvalidDecl();
if (ParamName) {
// Add the template parameter into the current scope.
S->AddDecl(Param);
IdResolver.AddDecl(Param);
}
return Param;
}
/// ActOnNonTypeTemplateParameter - Called when a C++ non-type
/// template parameter (e.g., "int Size" in "template<int Size>
/// class Array") has been parsed. S is the current scope and D is
/// the parsed declarator.
Sema::DeclTy *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
unsigned Depth,
unsigned Position) {
QualType T = GetTypeForDeclarator(D, S);
assert(S->isTemplateParamScope() &&
"Non-type template parameter not in template parameter scope!");
bool Invalid = false;
IdentifierInfo *ParamName = D.getIdentifier();
if (ParamName) {
NamedDecl *PrevDecl = LookupName(S, ParamName, LookupTagName);
if (PrevDecl && PrevDecl->isTemplateParameter())
Invalid = Invalid || DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
PrevDecl);
}
NonTypeTemplateParmDecl *Param
= NonTypeTemplateParmDecl::Create(Context, CurContext, D.getIdentifierLoc(),
Depth, Position, ParamName, T);
if (Invalid)
Param->setInvalidDecl();
if (D.getIdentifier()) {
// Add the template parameter into the current scope.
S->AddDecl(Param);
IdResolver.AddDecl(Param);
}
return Param;
}
/// ActOnTemplateTemplateParameter - Called when a C++ template template
/// parameter (e.g. T in template <template <typename> class T> class array)
/// has been parsed. S is the current scope.
Sema::DeclTy *Sema::ActOnTemplateTemplateParameter(Scope* S,
SourceLocation TmpLoc,
TemplateParamsTy *Params,
IdentifierInfo *Name,
SourceLocation NameLoc,
unsigned Depth,
unsigned Position)
{
assert(S->isTemplateParamScope() &&
"Template template parameter not in template parameter scope!");
// Construct the parameter object.
TemplateTemplateParmDecl *Param =
TemplateTemplateParmDecl::Create(Context, CurContext, TmpLoc, Depth,
Position, Name,
(TemplateParameterList*)Params);
// Make sure the parameter is valid.
// FIXME: Decl object is not currently invalidated anywhere so this doesn't
// do anything yet. However, if the template parameter list or (eventual)
// default value is ever invalidated, that will propagate here.
bool Invalid = false;
if (Invalid) {
Param->setInvalidDecl();
}
// If the tt-param has a name, then link the identifier into the scope
// and lookup mechanisms.
if (Name) {
S->AddDecl(Param);
IdResolver.AddDecl(Param);
}
return Param;
}
/// ActOnTemplateParameterList - Builds a TemplateParameterList that
/// contains the template parameters in Params/NumParams.
Sema::TemplateParamsTy *
Sema::ActOnTemplateParameterList(unsigned Depth,
SourceLocation ExportLoc,
SourceLocation TemplateLoc,
SourceLocation LAngleLoc,
DeclTy **Params, unsigned NumParams,
SourceLocation RAngleLoc) {
if (ExportLoc.isValid())
Diag(ExportLoc, diag::note_template_export_unsupported);
return TemplateParameterList::Create(Context, TemplateLoc, LAngleLoc,
(Decl**)Params, NumParams, RAngleLoc);
}
Sema::DeclTy *
Sema::ActOnClassTemplate(Scope *S, unsigned TagSpec, TagKind TK,
SourceLocation KWLoc, const CXXScopeSpec &SS,
IdentifierInfo *Name, SourceLocation NameLoc,
AttributeList *Attr,
MultiTemplateParamsArg TemplateParameterLists) {
assert(TemplateParameterLists.size() > 0 && "No template parameter lists?");
assert(TK != TK_Reference && "Can only declare or define class templates");
// Check that we can declare a template here.
if (CheckTemplateDeclScope(S, TemplateParameterLists))
return 0;
TagDecl::TagKind Kind;
switch (TagSpec) {
default: assert(0 && "Unknown tag type!");
case DeclSpec::TST_struct: Kind = TagDecl::TK_struct; break;
case DeclSpec::TST_union: Kind = TagDecl::TK_union; break;
case DeclSpec::TST_class: Kind = TagDecl::TK_class; break;
}
// There is no such thing as an unnamed class template.
if (!Name) {
Diag(KWLoc, diag::err_template_unnamed_class);
return 0;
}
// Find any previous declaration with this name.
LookupResult Previous = LookupParsedName(S, &SS, Name, LookupOrdinaryName,
true);
assert(!Previous.isAmbiguous() && "Ambiguity in class template redecl?");
NamedDecl *PrevDecl = 0;
if (Previous.begin() != Previous.end())
PrevDecl = *Previous.begin();
DeclContext *SemanticContext = CurContext;
if (SS.isNotEmpty() && !SS.isInvalid()) {
SemanticContext = static_cast<DeclContext*>(SS.getScopeRep());
// FIXME: need to match up several levels of template parameter
// lists here.
}
// FIXME: member templates!
TemplateParameterList *TemplateParams
= static_cast<TemplateParameterList *>(*TemplateParameterLists.release());
// If there is a previous declaration with the same name, check
// whether this is a valid redeclaration.
ClassTemplateDecl *PrevClassTemplate
= dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
if (PrevClassTemplate) {
// Ensure that the template parameter lists are compatible.
if (!TemplateParameterListsAreEqual(TemplateParams,
PrevClassTemplate->getTemplateParameters(),
/*Complain=*/true))
return 0;
// C++ [temp.class]p4:
// In a redeclaration, partial specialization, explicit
// specialization or explicit instantiation of a class template,
// the class-key shall agree in kind with the original class
// template declaration (7.1.5.3).
RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
if (PrevRecordDecl->getTagKind() != Kind) {
Diag(KWLoc, diag::err_use_with_wrong_tag) << Name;
Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
return 0;
}
// Check for redefinition of this class template.
if (TK == TK_Definition) {
if (TagDecl *Def = PrevRecordDecl->getDefinition(Context)) {
Diag(NameLoc, diag::err_redefinition) << Name;
Diag(Def->getLocation(), diag::note_previous_definition);
// FIXME: Would it make sense to try to "forget" the previous
// definition, as part of error recovery?
return 0;
}
}
} else if (PrevDecl && PrevDecl->isTemplateParameter()) {
// Maybe we will complain about the shadowed template parameter.
DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
// Just pretend that we didn't see the previous declaration.
PrevDecl = 0;
} else if (PrevDecl) {
// C++ [temp]p5:
// A class template shall not have the same name as any other
// template, class, function, object, enumeration, enumerator,
// namespace, or type in the same scope (3.3), except as specified
// in (14.5.4).
Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
Diag(PrevDecl->getLocation(), diag::note_previous_definition);
return 0;
}
// If we had a scope specifier, we better have a previous template
// declaration!
TagDecl *NewClass =
CXXRecordDecl::Create(Context, Kind, SemanticContext, NameLoc, Name,
PrevClassTemplate?
PrevClassTemplate->getTemplatedDecl() : 0);
ClassTemplateDecl *NewTemplate
= ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
DeclarationName(Name), TemplateParams,
NewClass);
// Set the lexical context of these templates
NewClass->setLexicalDeclContext(CurContext);
NewTemplate->setLexicalDeclContext(CurContext);
if (TK == TK_Definition)
NewClass->startDefinition();
if (Attr)
ProcessDeclAttributeList(NewClass, Attr);
PushOnScopeChains(NewTemplate, S);
return NewTemplate;
}
/// \brief Determine whether the given template parameter lists are
/// equivalent.
///
/// \param New The new template parameter list, typically written in the
/// source code as part of a new template declaration.
///
/// \param Old The old template parameter list, typically found via
/// name lookup of the template declared with this template parameter
/// list.
///
/// \param Complain If true, this routine will produce a diagnostic if
/// the template parameter lists are not equivalent.
///
/// \returns True if the template parameter lists are equal, false
/// otherwise.
bool
Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
TemplateParameterList *Old,
bool Complain,
bool IsTemplateTemplateParm) {
if (Old->size() != New->size()) {
if (Complain) {
Diag(New->getTemplateLoc(), diag::err_template_param_list_different_arity)
<< (New->size() > Old->size())
<< IsTemplateTemplateParm
<< SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
<< IsTemplateTemplateParm
<< SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
}
return false;
}
for (TemplateParameterList::iterator OldParm = Old->begin(),
OldParmEnd = Old->end(), NewParm = New->begin();
OldParm != OldParmEnd; ++OldParm, ++NewParm) {
if ((*OldParm)->getKind() != (*NewParm)->getKind()) {
Diag((*NewParm)->getLocation(), diag::err_template_param_different_kind)
<< IsTemplateTemplateParm;
Diag((*OldParm)->getLocation(), diag::note_template_prev_declaration)
<< IsTemplateTemplateParm;
return false;
}
if (isa<TemplateTypeParmDecl>(*OldParm)) {
// Okay; all template type parameters are equivalent (since we
// know we're at the same depth/level).
#ifndef NDEBUG
QualType OldParmType
= Context.getTypeDeclType(cast<TemplateTypeParmDecl>(*OldParm));
QualType NewParmType
= Context.getTypeDeclType(cast<TemplateTypeParmDecl>(*NewParm));
assert(Context.getCanonicalType(OldParmType) ==
Context.getCanonicalType(NewParmType) &&
"type parameter mismatch?");
#endif
} else if (NonTypeTemplateParmDecl *OldNTTP
= dyn_cast<NonTypeTemplateParmDecl>(*OldParm)) {
// The types of non-type template parameters must agree.
NonTypeTemplateParmDecl *NewNTTP
= cast<NonTypeTemplateParmDecl>(*NewParm);
if (Context.getCanonicalType(OldNTTP->getType()) !=
Context.getCanonicalType(NewNTTP->getType())) {
if (Complain) {
Diag(NewNTTP->getLocation(),
diag::err_template_nontype_parm_different_type)
<< NewNTTP->getType()
<< IsTemplateTemplateParm;
Diag(OldNTTP->getLocation(),
diag::note_template_nontype_parm_prev_declaration)
<< OldNTTP->getType();
}
return false;
}
} else {
// The template parameter lists of template template
// parameters must agree.
// FIXME: Could we perform a faster "type" comparison here?
assert(isa<TemplateTemplateParmDecl>(*OldParm) &&
"Only template template parameters handled here");
TemplateTemplateParmDecl *OldTTP
= cast<TemplateTemplateParmDecl>(*OldParm);
TemplateTemplateParmDecl *NewTTP
= cast<TemplateTemplateParmDecl>(*NewParm);
if (!TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
OldTTP->getTemplateParameters(),
Complain,
/*IsTemplateTemplateParm=*/true))
return false;
}
}
return true;
}
/// \brief Check whether a template can be declared within this scope.
///
/// If the template declaration is valid in this scope, returns
/// false. Otherwise, issues a diagnostic and returns true.
bool
Sema::CheckTemplateDeclScope(Scope *S,
MultiTemplateParamsArg &TemplateParameterLists) {
assert(TemplateParameterLists.size() > 0 && "Not a template");
// Find the nearest enclosing declaration scope.
while ((S->getFlags() & Scope::DeclScope) == 0 ||
(S->getFlags() & Scope::TemplateParamScope) != 0)
S = S->getParent();
TemplateParameterList *TemplateParams =
static_cast<TemplateParameterList*>(*TemplateParameterLists.get());
SourceLocation TemplateLoc = TemplateParams->getTemplateLoc();
SourceRange TemplateRange
= SourceRange(TemplateLoc, TemplateParams->getRAngleLoc());
// C++ [temp]p2:
// A template-declaration can appear only as a namespace scope or
// class scope declaration.
DeclContext *Ctx = static_cast<DeclContext *>(S->getEntity());
while (Ctx && isa<LinkageSpecDecl>(Ctx)) {
if (cast<LinkageSpecDecl>(Ctx)->getLanguage() != LinkageSpecDecl::lang_cxx)
return Diag(TemplateLoc, diag::err_template_linkage)
<< TemplateRange;
Ctx = Ctx->getParent();
}
if (Ctx && (Ctx->isFileContext() || Ctx->isRecord()))
return false;
return Diag(TemplateLoc, diag::err_template_outside_namespace_or_class_scope)
<< TemplateRange;
}
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