| //===--- 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/ExprCXX.h" |
| #include "clang/AST/NestedNameSpecifier.h" |
| #include "clang/Basic/PartialDiagnostic.h" |
| #include "clang/Parse/DeclSpec.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/Support/raw_ostream.h" |
| using namespace clang; |
| |
| /// \brief Compute the DeclContext that is associated with the given type. |
| /// |
| /// \param T the type for which we are attempting to find a DeclContext. |
| /// |
| /// \returns the declaration context represented by the type T, |
| /// or NULL if the declaration context cannot be computed (e.g., because it is |
| /// dependent and not the current instantiation). |
| DeclContext *Sema::computeDeclContext(QualType T) { |
| if (const TagType *Tag = T->getAs<TagType>()) |
| return Tag->getDecl(); |
| |
| return 0; |
| } |
| |
| /// \brief Compute the DeclContext that is associated with the given |
| /// scope specifier. |
| /// |
| /// \param SS the C++ scope specifier as it appears in the source |
| /// |
| /// \param EnteringContext when true, we will be entering the context of |
| /// this scope specifier, so we can retrieve the declaration context of a |
| /// class template or class template partial specialization even if it is |
| /// not the current instantiation. |
| /// |
| /// \returns the declaration context represented by the scope specifier @p SS, |
| /// or NULL if the declaration context cannot be computed (e.g., because it is |
| /// dependent and not the current instantiation). |
| DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS, |
| bool EnteringContext) { |
| 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; |
| |
| if (EnteringContext) { |
| if (const TemplateSpecializationType *SpecType |
| = dyn_cast_or_null<TemplateSpecializationType>(NNS->getAsType())) { |
| // We are entering the context of the nested name specifier, so try to |
| // match the nested name specifier to either a primary class template |
| // or a class template partial specialization. |
| if (ClassTemplateDecl *ClassTemplate |
| = dyn_cast_or_null<ClassTemplateDecl>( |
| SpecType->getTemplateName().getAsTemplateDecl())) { |
| QualType ContextType |
| = Context.getCanonicalType(QualType(SpecType, 0)); |
| |
| // If the type of the nested name specifier is the same as the |
| // injected class name of the named class template, we're entering |
| // into that class template definition. |
| QualType Injected = ClassTemplate->getInjectedClassNameType(Context); |
| if (Context.hasSameType(Injected, ContextType)) |
| return ClassTemplate->getTemplatedDecl(); |
| |
| // If the type of the nested name specifier is the same as the |
| // type of one of the class template's class template partial |
| // specializations, we're entering into the definition of that |
| // class template partial specialization. |
| if (ClassTemplatePartialSpecializationDecl *PartialSpec |
| = ClassTemplate->findPartialSpecialization(ContextType)) |
| return PartialSpec; |
| } |
| } else if (const RecordType *RecordT |
| = dyn_cast_or_null<RecordType>(NNS->getAsType())) { |
| // The nested name specifier refers to a member of a class template. |
| return RecordT->getDecl(); |
| } |
| } |
| |
| 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()->getAs<TagType>(); |
| 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"); |
| |
| if (!NNS->getAsType()) |
| return 0; |
| |
| 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: parameter packs) |
| // |
| // 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.getCanonicalType(Context.getTypeDeclType(Record)) == T) |
| return Record; |
| |
| if (ClassTemplateDecl *Template = Record->getDescribedClassTemplate()) { |
| QualType InjectedClassName |
| = Template->getInjectedClassNameType(Context); |
| if (T == Context.getCanonicalType(InjectedClassName)) |
| return Template->getTemplatedDecl(); |
| } |
| // FIXME: check for class template partial specializations |
| } |
| |
| 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, true); |
| 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)->getAs<TagType>(); |
| if (TagT->isBeingDefined()) |
| return false; |
| |
| // The type must be complete. |
| return RequireCompleteType(SS.getRange().getBegin(), |
| Context.getTypeDeclType(Tag), |
| PDiag(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); |
| } |
| |
| /// \brief Determines whether the given declaration is an valid acceptable |
| /// result for name lookup of a nested-name-specifier. |
| bool Sema::isAcceptableNestedNameSpecifier(NamedDecl *SD) { |
| if (!SD) |
| return false; |
| |
| // Namespace and namespace aliases are fine. |
| if (isa<NamespaceDecl>(SD) || isa<NamespaceAliasDecl>(SD)) |
| return true; |
| |
| if (!isa<TypeDecl>(SD)) |
| return false; |
| |
| // 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(cast<TypeDecl>(SD)); |
| if (T->isDependentType()) |
| return true; |
| else if (TypedefDecl *TD = dyn_cast<TypedefDecl>(SD)) { |
| if (TD->getUnderlyingType()->isRecordType() || |
| (Context.getLangOptions().CPlusPlus0x && |
| TD->getUnderlyingType()->isEnumeralType())) |
| return true; |
| } else if (isa<RecordDecl>(SD) || |
| (Context.getLangOptions().CPlusPlus0x && isa<EnumDecl>(SD))) |
| return true; |
| |
| return false; |
| } |
| |
| /// \brief If the given nested-name-specifier begins with a bare identifier |
| /// (e.g., Base::), perform name lookup for that identifier as a |
| /// nested-name-specifier within the given scope, and return the result of that |
| /// name lookup. |
| NamedDecl *Sema::FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS) { |
| if (!S || !NNS) |
| return 0; |
| |
| while (NNS->getPrefix()) |
| NNS = NNS->getPrefix(); |
| |
| if (NNS->getKind() != NestedNameSpecifier::Identifier) |
| return 0; |
| |
| LookupResult Found; |
| LookupName(Found, S, NNS->getAsIdentifier(), LookupNestedNameSpecifierName); |
| assert(!Found.isAmbiguous() && "Cannot handle ambiguities here yet"); |
| |
| NamedDecl *Result = Found.getAsSingleDecl(Context); |
| if (isAcceptableNestedNameSpecifier(Result)) |
| return Result; |
| |
| return 0; |
| } |
| |
| /// \brief Build a new nested-name-specifier for "identifier::", as described |
| /// by ActOnCXXNestedNameSpecifier. |
| /// |
| /// This routine differs only slightly from ActOnCXXNestedNameSpecifier, in |
| /// that it contains an extra parameter \p ScopeLookupResult, which provides |
| /// the result of name lookup within the scope of the nested-name-specifier |
| /// that was computed at template definitino time. |
| Sema::CXXScopeTy *Sema::BuildCXXNestedNameSpecifier(Scope *S, |
| const CXXScopeSpec &SS, |
| SourceLocation IdLoc, |
| SourceLocation CCLoc, |
| IdentifierInfo &II, |
| QualType ObjectType, |
| NamedDecl *ScopeLookupResult, |
| bool EnteringContext) { |
| NestedNameSpecifier *Prefix |
| = static_cast<NestedNameSpecifier *>(SS.getScopeRep()); |
| |
| // Determine where to perform name lookup |
| DeclContext *LookupCtx = 0; |
| bool isDependent = false; |
| if (!ObjectType.isNull()) { |
| // This nested-name-specifier occurs in a member access expression, e.g., |
| // x->B::f, and we are looking into the type of the object. |
| assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist"); |
| LookupCtx = computeDeclContext(ObjectType); |
| isDependent = ObjectType->isDependentType(); |
| } else if (SS.isSet()) { |
| // This nested-name-specifier occurs after another nested-name-specifier, |
| // so long into the context associated with the prior nested-name-specifier. |
| LookupCtx = computeDeclContext(SS, EnteringContext); |
| isDependent = isDependentScopeSpecifier(SS); |
| } |
| |
| LookupResult Found; |
| bool ObjectTypeSearchedInScope = false; |
| if (LookupCtx) { |
| // Perform "qualified" name lookup into the declaration context we |
| // computed, which is either the type of the base of a member access |
| // expression or the declaration context associated with a prior |
| // nested-name-specifier. |
| |
| // The declaration context must be complete. |
| if (!LookupCtx->isDependentContext() && RequireCompleteDeclContext(SS)) |
| return 0; |
| |
| LookupQualifiedName(Found, LookupCtx, &II, LookupNestedNameSpecifierName, |
| false); |
| |
| if (!ObjectType.isNull() && Found.getKind() == LookupResult::NotFound) { |
| // C++ [basic.lookup.classref]p4: |
| // If the id-expression in a class member access is a qualified-id of |
| // the form |
| // |
| // class-name-or-namespace-name::... |
| // |
| // the class-name-or-namespace-name following the . or -> operator is |
| // looked up both in the context of the entire postfix-expression and in |
| // the scope of the class of the object expression. If the name is found |
| // only in the scope of the class of the object expression, the name |
| // shall refer to a class-name. If the name is found only in the |
| // context of the entire postfix-expression, the name shall refer to a |
| // class-name or namespace-name. [...] |
| // |
| // Qualified name lookup into a class will not find a namespace-name, |
| // so we do not need to diagnoste that case specifically. However, |
| // this qualified name lookup may find nothing. In that case, perform |
| // unqualified name lookup in the given scope (if available) or |
| // reconstruct the result from when name lookup was performed at template |
| // definition time. |
| if (S) |
| LookupName(Found, S, &II, LookupNestedNameSpecifierName); |
| else if (ScopeLookupResult) |
| Found.addDecl(ScopeLookupResult); |
| |
| ObjectTypeSearchedInScope = true; |
| } |
| } else if (isDependent) { |
| // We were not able to compute the declaration context for a dependent |
| // base object type or prior nested-name-specifier, so this |
| // nested-name-specifier refers to an unknown specialization. Just build |
| // a dependent nested-name-specifier. |
| if (!Prefix) |
| return NestedNameSpecifier::Create(Context, &II); |
| |
| return NestedNameSpecifier::Create(Context, Prefix, &II); |
| } else { |
| // Perform unqualified name lookup in the current scope. |
| LookupName(Found, S, &II, LookupNestedNameSpecifierName); |
| } |
| |
| // FIXME: Deal with ambiguities cleanly. |
| NamedDecl *SD = Found.getAsSingleDecl(Context); |
| if (isAcceptableNestedNameSpecifier(SD)) { |
| if (!ObjectType.isNull() && !ObjectTypeSearchedInScope) { |
| // C++ [basic.lookup.classref]p4: |
| // [...] If the name is found in both contexts, the |
| // class-name-or-namespace-name shall refer to the same entity. |
| // |
| // We already found the name in the scope of the object. Now, look |
| // into the current scope (the scope of the postfix-expression) to |
| // see if we can find the same name there. As above, if there is no |
| // scope, reconstruct the result from the template instantiation itself. |
| NamedDecl *OuterDecl; |
| if (S) { |
| LookupResult FoundOuter; |
| LookupName(FoundOuter, S, &II, LookupNestedNameSpecifierName); |
| // FIXME: Handle ambiguities! |
| OuterDecl = FoundOuter.getAsSingleDecl(Context); |
| } else |
| OuterDecl = ScopeLookupResult; |
| |
| if (isAcceptableNestedNameSpecifier(OuterDecl) && |
| OuterDecl->getCanonicalDecl() != SD->getCanonicalDecl() && |
| (!isa<TypeDecl>(OuterDecl) || !isa<TypeDecl>(SD) || |
| !Context.hasSameType( |
| Context.getTypeDeclType(cast<TypeDecl>(OuterDecl)), |
| Context.getTypeDeclType(cast<TypeDecl>(SD))))) { |
| Diag(IdLoc, diag::err_nested_name_member_ref_lookup_ambiguous) |
| << &II; |
| Diag(SD->getLocation(), diag::note_ambig_member_ref_object_type) |
| << ObjectType; |
| Diag(OuterDecl->getLocation(), diag::note_ambig_member_ref_scope); |
| |
| // Fall through so that we'll pick the name we found in the object type, |
| // since that's probably what the user wanted anyway. |
| } |
| } |
| |
| if (NamespaceDecl *Namespace = dyn_cast<NamespaceDecl>(SD)) |
| return NestedNameSpecifier::Create(Context, Prefix, Namespace); |
| |
| // FIXME: It would be nice to maintain the namespace alias name, then |
| // see through that alias when resolving the nested-name-specifier down to |
| // a declaration context. |
| if (NamespaceAliasDecl *Alias = dyn_cast<NamespaceAliasDecl>(SD)) |
| return NestedNameSpecifier::Create(Context, Prefix, |
| |
| Alias->getNamespace()); |
| |
| QualType T = Context.getTypeDeclType(cast<TypeDecl>(SD)); |
| return NestedNameSpecifier::Create(Context, Prefix, false, |
| T.getTypePtr()); |
| } |
| |
| // 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) { |
| Found.clear(); |
| LookupName(Found, S, &II, LookupOrdinaryName); |
| SD = Found.getAsSingleDecl(Context); |
| } |
| |
| unsigned DiagID; |
| if (SD) |
| DiagID = diag::err_expected_class_or_namespace; |
| else if (SS.isSet()) { |
| DiagnoseMissingMember(IdLoc, DeclarationName(&II), |
| (NestedNameSpecifier *)SS.getScopeRep(), |
| SS.getRange()); |
| return 0; |
| } else |
| DiagID = diag::err_undeclared_var_use; |
| |
| if (SS.isSet()) |
| Diag(IdLoc, DiagID) << &II << SS.getRange(); |
| else |
| Diag(IdLoc, DiagID) << &II; |
| |
| return 0; |
| } |
| |
| /// 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, |
| TypeTy *ObjectTypePtr, |
| bool EnteringContext) { |
| return BuildCXXNestedNameSpecifier(S, SS, IdLoc, CCLoc, II, |
| QualType::getFromOpaquePtr(ObjectTypePtr), |
| /*ScopeLookupResult=*/0, EnteringContext); |
| } |
| |
| Sema::CXXScopeTy *Sema::ActOnCXXNestedNameSpecifier(Scope *S, |
| const CXXScopeSpec &SS, |
| TypeTy *Ty, |
| SourceRange TypeRange, |
| SourceLocation CCLoc) { |
| NestedNameSpecifier *Prefix |
| = static_cast<NestedNameSpecifier *>(SS.getScopeRep()); |
| QualType T = GetTypeFromParser(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. |
| bool Sema::ActOnCXXEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) { |
| assert(SS.isSet() && "Parser passed invalid CXXScopeSpec."); |
| if (DeclContext *DC = computeDeclContext(SS, true)) { |
| // Before we enter a declarator's context, we need to make sure that |
| // it is a complete declaration context. |
| if (!DC->isDependentContext() && RequireCompleteDeclContext(SS)) |
| return true; |
| |
| EnterDeclaratorContext(S, DC); |
| } |
| |
| return false; |
| } |
| |
| /// 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."); |
| if (SS.isInvalid()) |
| return; |
| if (computeDeclContext(SS, true)) |
| ExitDeclaratorContext(S); |
| } |