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//===--- SemaCXXScopeSpec.cpp - Semantic Analysis for C++ scope specifiers-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements C++ semantic analysis for scope specifiers.
//
//===----------------------------------------------------------------------===//
#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/Parse/DeclSpec.h"
#include "llvm/ADT/STLExtras.h"
using namespace clang;
/// \brief Compute the DeclContext that is associated with the given
/// scope specifier.
DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS) {
if (!SS.isSet() || SS.isInvalid())
return 0;
NestedNameSpecifier *NNS
= static_cast<NestedNameSpecifier *>(SS.getScopeRep());
if (NNS->isDependent()) {
// If this nested-name-specifier refers to the current
// instantiation, return its DeclContext.
if (CXXRecordDecl *Record = getCurrentInstantiationOf(NNS))
return Record;
else
return 0;
}
switch (NNS->getKind()) {
case NestedNameSpecifier::Identifier:
assert(false && "Dependent nested-name-specifier has no DeclContext");
break;
case NestedNameSpecifier::Namespace:
return NNS->getAsNamespace();
case NestedNameSpecifier::TypeSpec:
case NestedNameSpecifier::TypeSpecWithTemplate: {
const TagType *Tag = NNS->getAsType()->getAsTagType();
assert(Tag && "Non-tag type in nested-name-specifier");
return Tag->getDecl();
} break;
case NestedNameSpecifier::Global:
return Context.getTranslationUnitDecl();
}
// Required to silence a GCC warning.
return 0;
}
bool Sema::isDependentScopeSpecifier(const CXXScopeSpec &SS) {
if (!SS.isSet() || SS.isInvalid())
return false;
NestedNameSpecifier *NNS
= static_cast<NestedNameSpecifier *>(SS.getScopeRep());
return NNS->isDependent();
}
// \brief Determine whether this C++ scope specifier refers to an
// unknown specialization, i.e., a dependent type that is not the
// current instantiation.
bool Sema::isUnknownSpecialization(const CXXScopeSpec &SS) {
if (!isDependentScopeSpecifier(SS))
return false;
NestedNameSpecifier *NNS
= static_cast<NestedNameSpecifier *>(SS.getScopeRep());
return getCurrentInstantiationOf(NNS) == 0;
}
/// \brief If the given nested name specifier refers to the current
/// instantiation, return the declaration that corresponds to that
/// current instantiation (C++0x [temp.dep.type]p1).
///
/// \param NNS a dependent nested name specifier.
CXXRecordDecl *Sema::getCurrentInstantiationOf(NestedNameSpecifier *NNS) {
assert(getLangOptions().CPlusPlus && "Only callable in C++");
assert(NNS->isDependent() && "Only dependent nested-name-specifier allowed");
QualType T = QualType(NNS->getAsType(), 0);
// If the nested name specifier does not refer to a type, then it
// does not refer to the current instantiation.
if (T.isNull())
return 0;
T = Context.getCanonicalType(T);
for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getParent()) {
// If we've hit a namespace or the global scope, then the
// nested-name-specifier can't refer to the current instantiation.
if (Ctx->isFileContext())
return 0;
// Skip non-class contexts.
CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
if (!Record)
continue;
// If this record type is not dependent,
if (!Record->isDependentType())
return 0;
// C++ [temp.dep.type]p1:
//
// In the definition of a class template, a nested class of a
// class template, a member of a class template, or a member of a
// nested class of a class template, a name refers to the current
// instantiation if it is
// -- the injected-class-name (9) of the class template or
// nested class,
// -- in the definition of a primary class template, the name
// of the class template followed by the template argument
// list of the primary template (as described below)
// enclosed in <>,
// -- in the definition of a nested class of a class template,
// the name of the nested class referenced as a member of
// the current instantiation, or
// -- in the definition of a partial specialization, the name
// of the class template followed by the template argument
// list of the partial specialization enclosed in <>. If
// the nth template parameter is a parameter pack, the nth
// template argument is a pack expansion (14.6.3) whose
// pattern is the name of the parameter pack. (FIXME)
//
// All of these options come down to having the
// nested-name-specifier type that is equivalent to the
// injected-class-name of one of the types that is currently in
// our context.
if (Context.getTypeDeclType(Record) == T)
return Record;
if (ClassTemplateDecl *Template = Record->getDescribedClassTemplate()) {
QualType InjectedClassName
= Template->getInjectedClassNameType(Context);
if (T == Context.getCanonicalType(InjectedClassName))
return Template->getTemplatedDecl();
}
}
return 0;
}
/// \brief Require that the context specified by SS be complete.
///
/// If SS refers to a type, this routine checks whether the type is
/// complete enough (or can be made complete enough) for name lookup
/// into the DeclContext. A type that is not yet completed can be
/// considered "complete enough" if it is a class/struct/union/enum
/// that is currently being defined. Or, if we have a type that names
/// a class template specialization that is not a complete type, we
/// will attempt to instantiate that class template.
bool Sema::RequireCompleteDeclContext(const CXXScopeSpec &SS) {
if (!SS.isSet() || SS.isInvalid())
return false;
DeclContext *DC = computeDeclContext(SS);
if (TagDecl *Tag = dyn_cast<TagDecl>(DC)) {
// If we're currently defining this type, then lookup into the
// type is okay: don't complain that it isn't complete yet.
const TagType *TagT = Context.getTypeDeclType(Tag)->getAsTagType();
if (TagT->isBeingDefined())
return false;
// The type must be complete.
return RequireCompleteType(SS.getRange().getBegin(),
Context.getTypeDeclType(Tag),
diag::err_incomplete_nested_name_spec,
SS.getRange());
}
return false;
}
/// ActOnCXXGlobalScopeSpecifier - Return the object that represents the
/// global scope ('::').
Sema::CXXScopeTy *Sema::ActOnCXXGlobalScopeSpecifier(Scope *S,
SourceLocation CCLoc) {
return NestedNameSpecifier::GlobalSpecifier(Context);
}
/// ActOnCXXNestedNameSpecifier - Called during parsing of a
/// nested-name-specifier. e.g. for "foo::bar::" we parsed "foo::" and now
/// we want to resolve "bar::". 'SS' is empty or the previously parsed
/// nested-name part ("foo::"), 'IdLoc' is the source location of 'bar',
/// 'CCLoc' is the location of '::' and 'II' is the identifier for 'bar'.
/// Returns a CXXScopeTy* object representing the C++ scope.
Sema::CXXScopeTy *Sema::ActOnCXXNestedNameSpecifier(Scope *S,
const CXXScopeSpec &SS,
SourceLocation IdLoc,
SourceLocation CCLoc,
IdentifierInfo &II) {
NestedNameSpecifier *Prefix
= static_cast<NestedNameSpecifier *>(SS.getScopeRep());
// If the prefix already refers to an unknown specialization, there
// is no name lookup to perform. Just build the resulting
// nested-name-specifier.
if (Prefix && isUnknownSpecialization(SS))
return NestedNameSpecifier::Create(Context, Prefix, &II);
NamedDecl *SD = LookupParsedName(S, &SS, &II, LookupNestedNameSpecifierName);
if (SD) {
if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD))
return NestedNameSpecifier::Create(Context, Prefix, Namespace);
if (TypeDecl *Type = dyn_cast<TypeDecl>(SD)) {
// Determine whether we have a class (or, in C++0x, an enum) or
// a typedef thereof. If so, build the nested-name-specifier.
QualType T = Context.getTypeDeclType(Type);
bool AcceptableType = false;
if (T->isDependentType())
AcceptableType = true;
else if (TypedefDecl *TD = dyn_cast<TypedefDecl>(SD)) {
if (TD->getUnderlyingType()->isRecordType() ||
(getLangOptions().CPlusPlus0x &&
TD->getUnderlyingType()->isEnumeralType()))
AcceptableType = true;
} else if (isa<RecordDecl>(Type) ||
(getLangOptions().CPlusPlus0x && isa<EnumDecl>(Type)))
AcceptableType = true;
if (AcceptableType)
return NestedNameSpecifier::Create(Context, Prefix, false,
T.getTypePtr());
}
if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD))
return NestedNameSpecifier::Create(Context, Prefix,
Alias->getNamespace());
// Fall through to produce an error: we found something that isn't
// a class or a namespace.
}
// If we didn't find anything during our lookup, try again with
// ordinary name lookup, which can help us produce better error
// messages.
if (!SD)
SD = LookupParsedName(S, &SS, &II, LookupOrdinaryName);
unsigned DiagID;
if (SD)
DiagID = diag::err_expected_class_or_namespace;
else if (SS.isSet())
DiagID = diag::err_typecheck_no_member;
else
DiagID = diag::err_undeclared_var_use;
if (SS.isSet())
Diag(IdLoc, DiagID) << &II << SS.getRange();
else
Diag(IdLoc, DiagID) << &II;
return 0;
}
Sema::CXXScopeTy *Sema::ActOnCXXNestedNameSpecifier(Scope *S,
const CXXScopeSpec &SS,
TypeTy *Ty,
SourceRange TypeRange,
SourceLocation CCLoc) {
NestedNameSpecifier *Prefix
= static_cast<NestedNameSpecifier *>(SS.getScopeRep());
QualType T = QualType::getFromOpaquePtr(Ty);
return NestedNameSpecifier::Create(Context, Prefix, /*FIXME:*/false,
T.getTypePtr());
}
/// ActOnCXXEnterDeclaratorScope - Called when a C++ scope specifier (global
/// scope or nested-name-specifier) is parsed, part of a declarator-id.
/// After this method is called, according to [C++ 3.4.3p3], names should be
/// looked up in the declarator-id's scope, until the declarator is parsed and
/// ActOnCXXExitDeclaratorScope is called.
/// The 'SS' should be a non-empty valid CXXScopeSpec.
void Sema::ActOnCXXEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
assert(PreDeclaratorDC == 0 && "Previous declarator context not popped?");
PreDeclaratorDC = static_cast<DeclContext*>(S->getEntity());
CurContext = computeDeclContext(SS);
assert(CurContext && "No context?");
S->setEntity(CurContext);
}
/// ActOnCXXExitDeclaratorScope - Called when a declarator that previously
/// invoked ActOnCXXEnterDeclaratorScope(), is finished. 'SS' is the same
/// CXXScopeSpec that was passed to ActOnCXXEnterDeclaratorScope as well.
/// Used to indicate that names should revert to being looked up in the
/// defining scope.
void Sema::ActOnCXXExitDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
assert(SS.isSet() && "Parser passed invalid CXXScopeSpec.");
assert(S->getEntity() == computeDeclContext(SS) && "Context imbalance!");
S->setEntity(PreDeclaratorDC);
PreDeclaratorDC = 0;
// Reset CurContext to the nearest enclosing context.
while (!S->getEntity() && S->getParent())
S = S->getParent();
CurContext = static_cast<DeclContext*>(S->getEntity());
assert(CurContext && "No context?");
}