diff options
Diffstat (limited to 'clang/lib/Sema/SemaModule.cpp')
| -rw-r--r-- | clang/lib/Sema/SemaModule.cpp | 472 |
1 files changed, 472 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaModule.cpp b/clang/lib/Sema/SemaModule.cpp index 7c982bc..98ebd70 100644 --- a/clang/lib/Sema/SemaModule.cpp +++ b/clang/lib/Sema/SemaModule.cpp @@ -13,6 +13,7 @@ #include "clang/AST/ASTConsumer.h" #include "clang/AST/ASTMutationListener.h" +#include "clang/AST/RecursiveASTVisitor.h" #include "clang/Lex/HeaderSearch.h" #include "clang/Lex/Preprocessor.h" #include "clang/Sema/ParsedAttr.h" @@ -485,6 +486,7 @@ Sema::ActOnModuleDecl(SourceLocation StartLoc, SourceLocation ModuleLoc, // implementation unit importing its interface). Make this module visible // and return the import decl to be added to the current TU. if (Interface) { + HadImportedNamedModules = true; makeTransitiveImportsVisible(getASTContext(), VisibleModules, Interface, Mod, ModuleLoc, @@ -728,6 +730,8 @@ DeclResult Sema::ActOnModuleImport(SourceLocation StartLoc, getCurrentModule()->Imports.insert(Mod); } + HadImportedNamedModules = true; + return Import; } @@ -1102,3 +1106,471 @@ bool Sema::isCurrentModulePurview() const { return false; } } + +//===----------------------------------------------------------------------===// +// Checking Exposure in modules // +//===----------------------------------------------------------------------===// + +namespace { +class ExposureChecker { +public: + ExposureChecker(Sema &S) : SemaRef(S) {} + + bool checkExposure(const VarDecl *D, bool Diag); + bool checkExposure(const CXXRecordDecl *D, bool Diag); + bool checkExposure(const Stmt *S, bool Diag); + bool checkExposure(const FunctionDecl *D, bool Diag); + bool checkExposure(const NamedDecl *D, bool Diag); + void checkExposureInContext(const DeclContext *DC); + bool isExposureCandidate(const NamedDecl *D); + + bool isTULocal(QualType Ty); + bool isTULocal(const NamedDecl *ND); + bool isTULocal(const Expr *E); + + Sema &SemaRef; + +private: + llvm::DenseSet<const NamedDecl *> ExposureSet; + llvm::DenseSet<const NamedDecl *> KnownNonExposureSet; +}; + +bool ExposureChecker::isTULocal(QualType Ty) { + // [basic.link]p15: + // An entity is TU-local if it is + // - a type, type alias, namespace, namespace alias, function, variable, or + // template that + // -- has internal linkage, or + return Ty->getLinkage() == Linkage::Internal; + + // TODO: + // [basic.link]p15.2: + // a type with no name that is defined outside a class-specifier, function + // body, or initializer or is introduced by a defining-type-specifier that + // is used to declare only TU-local entities, +} + +bool ExposureChecker::isTULocal(const NamedDecl *D) { + if (!D) + return false; + + // [basic.link]p15: + // An entity is TU-local if it is + // - a type, type alias, namespace, namespace alias, function, variable, or + // template that + // -- has internal linkage, or + if (D->getLinkageInternal() == Linkage::Internal) + return true; + + if (D->isInAnonymousNamespace()) + return true; + + // [basic.link]p15.1.2: + // does not have a name with linkage and is declared, or introduced by a + // lambda-expression, within the definition of a TU-local entity, + if (D->getLinkageInternal() == Linkage::None) + if (auto *ND = dyn_cast<NamedDecl>(D->getDeclContext()); + ND && isTULocal(ND)) + return true; + + // [basic.link]p15.3, p15.4: + // - a specialization of a TU-local template, + // - a specialization of a template with any TU-local template argument, or + ArrayRef<TemplateArgument> TemplateArgs; + NamedDecl *PrimaryTemplate = nullptr; + if (auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(D)) { + TemplateArgs = CTSD->getTemplateArgs().asArray(); + PrimaryTemplate = CTSD->getSpecializedTemplate(); + if (isTULocal(PrimaryTemplate)) + return true; + } else if (auto *VTSD = dyn_cast<VarTemplateSpecializationDecl>(D)) { + TemplateArgs = VTSD->getTemplateArgs().asArray(); + PrimaryTemplate = VTSD->getSpecializedTemplate(); + if (isTULocal(PrimaryTemplate)) + return true; + } else if (auto *FD = dyn_cast<FunctionDecl>(D)) { + if (auto *TAList = FD->getTemplateSpecializationArgs()) + TemplateArgs = TAList->asArray(); + + PrimaryTemplate = FD->getPrimaryTemplate(); + if (isTULocal(PrimaryTemplate)) + return true; + } + + if (!PrimaryTemplate) + // Following off, we only check for specializations. + return false; + + if (KnownNonExposureSet.count(D)) + return false; + + for (auto &TA : TemplateArgs) { + switch (TA.getKind()) { + case TemplateArgument::Type: + if (isTULocal(TA.getAsType())) + return true; + break; + case TemplateArgument::Declaration: + if (isTULocal(TA.getAsDecl())) + return true; + break; + default: + break; + } + } + + // [basic.link]p15.5 + // - a specialization of a template whose (possibly instantiated) declaration + // is an exposure. + if (checkExposure(PrimaryTemplate, /*Diag=*/false)) + return true; + + // Avoid calling checkExposure again since it is expensive. + KnownNonExposureSet.insert(D); + return false; +} + +bool ExposureChecker::isTULocal(const Expr *E) { + if (!E) + return false; + + // [basic.link]p16: + // A value or object is TU-local if either + // - it is of TU-local type, + if (isTULocal(E->getType())) + return true; + + E = E->IgnoreParenImpCasts(); + // [basic.link]p16.2: + // - it is, or is a pointer to, a TU-local function or the object associated + // with a TU-local variable, + // - it is an object of class or array type and any of its subobjects or any + // of the objects or functions to which its non-static data members of + // reference type refer is TU-local and is usable in constant expressions, or + // FIXME: But how can we know the value of pointers or arrays at compile time? + if (const auto *DRE = dyn_cast<DeclRefExpr>(E)) { + if (auto *FD = dyn_cast_or_null<FunctionDecl>(DRE->getFoundDecl())) + return isTULocal(FD); + else if (auto *VD = dyn_cast_or_null<VarDecl>(DRE->getFoundDecl())) + return isTULocal(VD); + else if (auto *RD = dyn_cast_or_null<CXXRecordDecl>(DRE->getFoundDecl())) + return isTULocal(RD); + } + + // TODO: + // [basic.link]p16.4: + // it is a reflection value that represents... + + return false; +} + +bool ExposureChecker::isExposureCandidate(const NamedDecl *D) { + if (!D) + return false; + + // [basic.link]p17: + // If a (possibly instantiated) declaration of, or a deduction guide for, + // a non-TU-local entity in a module interface unit + // (outside the private-module-fragment, if any) or + // module partition is an exposure, the program is ill-formed. + Module *M = D->getOwningModule(); + if (!M || !M->isInterfaceOrPartition()) + return false; + + if (D->isImplicit()) + return false; + + // [basic.link]p14: + // A declaration is an exposure if it either names a TU-local entity + // (defined below), ignoring: + // ... + // - friend declarations in a class definition + if (D->getFriendObjectKind() && + isa<CXXRecordDecl>(D->getLexicalDeclContext())) + return false; + + return true; +} + +bool ExposureChecker::checkExposure(const NamedDecl *D, bool Diag) { + if (!isExposureCandidate(D)) + return false; + + if (auto *FD = dyn_cast<FunctionDecl>(D)) + return checkExposure(FD, Diag); + if (auto *FTD = dyn_cast<FunctionTemplateDecl>(D)) + return checkExposure(FTD->getTemplatedDecl(), Diag); + + if (auto *VD = dyn_cast<VarDecl>(D)) + return checkExposure(VD, Diag); + if (auto *VTD = dyn_cast<VarTemplateDecl>(D)) + return checkExposure(VTD->getTemplatedDecl(), Diag); + + if (auto *RD = dyn_cast<CXXRecordDecl>(D)) + return checkExposure(RD, Diag); + + if (auto *CTD = dyn_cast<ClassTemplateDecl>(D)) + return checkExposure(CTD->getTemplatedDecl(), Diag); + + return false; +} + +bool ExposureChecker::checkExposure(const FunctionDecl *FD, bool Diag) { + bool IsExposure = false; + if (isTULocal(FD->getReturnType())) { + IsExposure = true; + if (Diag) + SemaRef.Diag(FD->getReturnTypeSourceRange().getBegin(), + diag::warn_exposure) + << FD->getReturnType(); + } + + for (ParmVarDecl *Parms : FD->parameters()) + if (isTULocal(Parms->getType())) { + IsExposure = true; + if (Diag) + SemaRef.Diag(Parms->getLocation(), diag::warn_exposure) + << Parms->getType(); + } + + bool IsImplicitInstantiation = + FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation; + + // [basic.link]p14: + // A declaration is an exposure if it either names a TU-local entity + // (defined below), ignoring: + // - the function-body for a non-inline function or function template + // (but not the deduced return + // type for a (possibly instantiated) definition of a function with a + // declared return type that uses a placeholder type + // ([dcl.spec.auto])), + Diag &= + (FD->isInlined() || IsImplicitInstantiation) && !FD->isDependentContext(); + + IsExposure |= checkExposure(FD->getBody(), Diag); + if (IsExposure) + ExposureSet.insert(FD); + + return IsExposure; +} + +bool ExposureChecker::checkExposure(const VarDecl *VD, bool Diag) { + bool IsExposure = false; + // [basic.link]p14: + // A declaration is an exposure if it either names a TU-local entity (defined + // below), ignoring: + // ... + // or defines a constexpr variable initialized to a TU-local value (defined + // below). + if (VD->isConstexpr() && isTULocal(VD->getInit())) { + IsExposure = true; + if (Diag) + SemaRef.Diag(VD->getInit()->getExprLoc(), diag::warn_exposure) + << VD->getInit(); + } + + if (isTULocal(VD->getType())) { + IsExposure = true; + if (Diag) + SemaRef.Diag(VD->getLocation(), diag::warn_exposure) << VD->getType(); + } + + // [basic.link]p14: + // ..., ignoring: + // - the initializer for a variable or variable template (but not the + // variable's type), + // + // Note: although the spec says to ignore the initializer for all variable, + // for the code we generated now for inline variables, it is dangerous if the + // initializer of an inline variable is TULocal. + Diag &= !VD->getDeclContext()->isDependentContext() && VD->isInline(); + IsExposure |= checkExposure(VD->getInit(), Diag); + if (IsExposure) + ExposureSet.insert(VD); + + return IsExposure; +} + +bool ExposureChecker::checkExposure(const CXXRecordDecl *RD, bool Diag) { + if (!RD->hasDefinition()) + return false; + + bool IsExposure = false; + for (CXXMethodDecl *Method : RD->methods()) + IsExposure |= checkExposure(Method, Diag); + + for (FieldDecl *FD : RD->fields()) { + if (isTULocal(FD->getType())) { + IsExposure = true; + if (Diag) + SemaRef.Diag(FD->getLocation(), diag::warn_exposure) << FD->getType(); + } + } + + for (const CXXBaseSpecifier &Base : RD->bases()) { + if (isTULocal(Base.getType())) { + IsExposure = true; + if (Diag) + SemaRef.Diag(Base.getBaseTypeLoc(), diag::warn_exposure) + << Base.getType(); + } + } + + if (IsExposure) + ExposureSet.insert(RD); + + return IsExposure; +} + +template <typename CallbackTy> +class ReferenceTULocalChecker + : public clang::RecursiveASTVisitor<ReferenceTULocalChecker<CallbackTy>> { +public: + ReferenceTULocalChecker(ExposureChecker &C, CallbackTy &&Callback) + : Checker(C), Callback(std::move(Callback)) {} + + bool VisitDeclRefExpr(DeclRefExpr *DRE) { + ValueDecl *Referenced = DRE->getDecl(); + if (!Referenced) + return true; + + if (!Checker.isTULocal(Referenced)) + // We don't care if the referenced declaration is not TU-local. + return true; + + Qualifiers Qual = DRE->getType().getQualifiers(); + // [basic.link]p14: + // A declaration is an exposure if it either names a TU-local entity + // (defined below), ignoring: + // ... + // - any reference to a non-volatile const object ... + if (Qual.hasConst() && !Qual.hasVolatile()) + return true; + + // [basic.link]p14: + // ..., ignoring: + // ... + // (p14.4) - ... or reference with internal or no linkage initialized with + // a constant expression that is not an odr-use + ASTContext &Context = Referenced->getASTContext(); + Linkage L = Referenced->getLinkageInternal(); + if (DRE->isNonOdrUse() && (L == Linkage::Internal || L == Linkage::None)) + if (auto *VD = dyn_cast<VarDecl>(Referenced); + VD && VD->getInit() && !VD->getInit()->isValueDependent() && + VD->getInit()->isConstantInitializer(Context, /*IsForRef=*/false)) + return true; + + Callback(DRE, Referenced); + return true; + } + + ExposureChecker &Checker; + CallbackTy Callback; +}; + +template <typename CallbackTy> +ReferenceTULocalChecker(ExposureChecker &, CallbackTy &&) + -> ReferenceTULocalChecker<CallbackTy>; + +bool ExposureChecker::checkExposure(const Stmt *S, bool Diag) { + if (!S) + return false; + + bool HasReferencedTULocals = false; + ReferenceTULocalChecker Checker( + *this, [this, &HasReferencedTULocals, Diag](DeclRefExpr *DRE, + ValueDecl *Referenced) { + if (Diag) { + SemaRef.Diag(DRE->getExprLoc(), diag::warn_exposure) << Referenced; + } + HasReferencedTULocals = true; + }); + Checker.TraverseStmt(const_cast<Stmt *>(S)); + return HasReferencedTULocals; +} + +void ExposureChecker::checkExposureInContext(const DeclContext *DC) { + for (auto *TopD : DC->noload_decls()) { + auto *TopND = dyn_cast<NamedDecl>(TopD); + if (!TopND) + continue; + + if (auto *Namespace = dyn_cast<NamespaceDecl>(TopND)) { + checkExposureInContext(Namespace); + continue; + } + + // [basic.link]p17: + // If a (possibly instantiated) declaration of, or a deduction guide for, + // a non-TU-local entity in a module interface unit + // (outside the private-module-fragment, if any) or + // module partition is an exposure, the program is ill-formed. + if (!TopND->isFromASTFile() && isExposureCandidate(TopND) && + !isTULocal(TopND)) + checkExposure(TopND, /*Diag=*/true); + } +} + +} // namespace + +void Sema::checkExposure(const TranslationUnitDecl *TU) { + if (!TU) + return; + + ExposureChecker Checker(*this); + + Module *M = TU->getOwningModule(); + if (M && M->isInterfaceOrPartition()) + Checker.checkExposureInContext(TU); + + // [basic.link]p18: + // If a declaration that appears in one translation unit names a TU-local + // entity declared in another translation unit that is not a header unit, + // the program is ill-formed. + for (auto FDAndInstantiationLocPair : PendingCheckReferenceForTULocal) { + FunctionDecl *FD = FDAndInstantiationLocPair.first; + SourceLocation PointOfInstantiation = FDAndInstantiationLocPair.second; + + if (!FD->hasBody()) + continue; + + ReferenceTULocalChecker(Checker, [&, this](DeclRefExpr *DRE, + ValueDecl *Referenced) { + // A "defect" in current implementation. Now an implicit instantiation of + // a template, the instantiation is considered to be in the same module + // unit as the template instead of the module unit where the instantiation + // happens. + // + // See test/Modules/Exposre-2.cppm for example. + if (!Referenced->isFromASTFile()) + return; + + if (!Referenced->isInAnotherModuleUnit()) + return; + + // This is not standard conforming. But given there are too many static + // (inline) functions in headers in existing code, it is more user + // friendly to ignore them temporarily now. maybe we can have another flag + // for this. + if (Referenced->getOwningModule()->isExplicitGlobalModule() && + isa<FunctionDecl>(Referenced)) + return; + + Diag(PointOfInstantiation, + diag::warn_reference_tu_local_entity_in_other_tu) + << FD << Referenced + << Referenced->getOwningModule()->getTopLevelModuleName(); + }).TraverseStmt(FD->getBody()); + } +} + +void Sema::checkReferenceToTULocalFromOtherTU( + FunctionDecl *FD, SourceLocation PointOfInstantiation) { + // Checking if a declaration have any reference to TU-local entities in other + // TU is expensive. Try to avoid it as much as possible. + if (!FD || !HadImportedNamedModules) + return; + + PendingCheckReferenceForTULocal.push_back( + std::make_pair(FD, PointOfInstantiation)); +} |