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Diffstat (limited to 'lib/Sema/SemaCXXScopeSpec.cpp')
| -rw-r--r-- | lib/Sema/SemaCXXScopeSpec.cpp | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp new file mode 100644 index 000000000000..11ac0bd30056 --- /dev/null +++ b/lib/Sema/SemaCXXScopeSpec.cpp @@ -0,0 +1,312 @@ +//===--- 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?"); +} |