blob: bcb9f05ca3c963743754a6f719907818e0c4c609 [file] [log] [blame]
//===- Decl.cpp - Declaration AST Node Implementation ---------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the Decl subclasses.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/Decl.h"
#include "Linkage.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTDiagnostic.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/ASTMutationListener.h"
#include "clang/AST/CanonicalType.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclOpenMP.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/ODRHash.h"
#include "clang/AST/PrettyDeclStackTrace.h"
#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/Redeclarable.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/Linkage.h"
#include "clang/Basic/Module.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/SanitizerBlacklist.h"
#include "clang/Basic/Sanitizers.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Basic/TargetCXXABI.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/Visibility.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstring>
#include <memory>
#include <string>
#include <tuple>
#include <type_traits>
using namespace clang;
Decl *clang::getPrimaryMergedDecl(Decl *D) {
return D->getASTContext().getPrimaryMergedDecl(D);
}
void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const {
SourceLocation Loc = this->Loc;
if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation();
if (Loc.isValid()) {
Loc.print(OS, Context.getSourceManager());
OS << ": ";
}
OS << Message;
if (auto *ND = dyn_cast_or_null<NamedDecl>(TheDecl)) {
OS << " '";
ND->getNameForDiagnostic(OS, Context.getPrintingPolicy(), true);
OS << "'";
}
OS << '\n';
}
// Defined here so that it can be inlined into its direct callers.
bool Decl::isOutOfLine() const {
return !getLexicalDeclContext()->Equals(getDeclContext());
}
TranslationUnitDecl::TranslationUnitDecl(ASTContext &ctx)
: Decl(TranslationUnit, nullptr, SourceLocation()),
DeclContext(TranslationUnit), Ctx(ctx) {}
//===----------------------------------------------------------------------===//
// NamedDecl Implementation
//===----------------------------------------------------------------------===//
// Visibility rules aren't rigorously externally specified, but here
// are the basic principles behind what we implement:
//
// 1. An explicit visibility attribute is generally a direct expression
// of the user's intent and should be honored. Only the innermost
// visibility attribute applies. If no visibility attribute applies,
// global visibility settings are considered.
//
// 2. There is one caveat to the above: on or in a template pattern,
// an explicit visibility attribute is just a default rule, and
// visibility can be decreased by the visibility of template
// arguments. But this, too, has an exception: an attribute on an
// explicit specialization or instantiation causes all the visibility
// restrictions of the template arguments to be ignored.
//
// 3. A variable that does not otherwise have explicit visibility can
// be restricted by the visibility of its type.
//
// 4. A visibility restriction is explicit if it comes from an
// attribute (or something like it), not a global visibility setting.
// When emitting a reference to an external symbol, visibility
// restrictions are ignored unless they are explicit.
//
// 5. When computing the visibility of a non-type, including a
// non-type member of a class, only non-type visibility restrictions
// are considered: the 'visibility' attribute, global value-visibility
// settings, and a few special cases like __private_extern.
//
// 6. When computing the visibility of a type, including a type member
// of a class, only type visibility restrictions are considered:
// the 'type_visibility' attribute and global type-visibility settings.
// However, a 'visibility' attribute counts as a 'type_visibility'
// attribute on any declaration that only has the former.
//
// The visibility of a "secondary" entity, like a template argument,
// is computed using the kind of that entity, not the kind of the
// primary entity for which we are computing visibility. For example,
// the visibility of a specialization of either of these templates:
// template <class T, bool (&compare)(T, X)> bool has_match(list<T>, X);
// template <class T, bool (&compare)(T, X)> class matcher;
// is restricted according to the type visibility of the argument 'T',
// the type visibility of 'bool(&)(T,X)', and the value visibility of
// the argument function 'compare'. That 'has_match' is a value
// and 'matcher' is a type only matters when looking for attributes
// and settings from the immediate context.
/// Does this computation kind permit us to consider additional
/// visibility settings from attributes and the like?
static bool hasExplicitVisibilityAlready(LVComputationKind computation) {
return computation.IgnoreExplicitVisibility;
}
/// Given an LVComputationKind, return one of the same type/value sort
/// that records that it already has explicit visibility.
static LVComputationKind
withExplicitVisibilityAlready(LVComputationKind Kind) {
Kind.IgnoreExplicitVisibility = true;
return Kind;
}
static Optional<Visibility> getExplicitVisibility(const NamedDecl *D,
LVComputationKind kind) {
assert(!kind.IgnoreExplicitVisibility &&
"asking for explicit visibility when we shouldn't be");
return D->getExplicitVisibility(kind.getExplicitVisibilityKind());
}
/// Is the given declaration a "type" or a "value" for the purposes of
/// visibility computation?
static bool usesTypeVisibility(const NamedDecl *D) {
return isa<TypeDecl>(D) ||
isa<ClassTemplateDecl>(D) ||
isa<ObjCInterfaceDecl>(D);
}
/// Does the given declaration have member specialization information,
/// and if so, is it an explicit specialization?
template <class T> static typename
std::enable_if<!std::is_base_of<RedeclarableTemplateDecl, T>::value, bool>::type
isExplicitMemberSpecialization(const T *D) {
if (const MemberSpecializationInfo *member =
D->getMemberSpecializationInfo()) {
return member->isExplicitSpecialization();
}
return false;
}
/// For templates, this question is easier: a member template can't be
/// explicitly instantiated, so there's a single bit indicating whether
/// or not this is an explicit member specialization.
static bool isExplicitMemberSpecialization(const RedeclarableTemplateDecl *D) {
return D->isMemberSpecialization();
}
/// Given a visibility attribute, return the explicit visibility
/// associated with it.
template <class T>
static Visibility getVisibilityFromAttr(const T *attr) {
switch (attr->getVisibility()) {
case T::Default:
return DefaultVisibility;
case T::Hidden:
return HiddenVisibility;
case T::Protected:
return ProtectedVisibility;
}
llvm_unreachable("bad visibility kind");
}
/// Return the explicit visibility of the given declaration.
static Optional<Visibility> getVisibilityOf(const NamedDecl *D,
NamedDecl::ExplicitVisibilityKind kind) {
// If we're ultimately computing the visibility of a type, look for
// a 'type_visibility' attribute before looking for 'visibility'.
if (kind == NamedDecl::VisibilityForType) {
if (const auto *A = D->getAttr<TypeVisibilityAttr>()) {
return getVisibilityFromAttr(A);
}
}
// If this declaration has an explicit visibility attribute, use it.
if (const auto *A = D->getAttr<VisibilityAttr>()) {
return getVisibilityFromAttr(A);
}
return None;
}
LinkageInfo LinkageComputer::getLVForType(const Type &T,
LVComputationKind computation) {
if (computation.IgnoreAllVisibility)
return LinkageInfo(T.getLinkage(), DefaultVisibility, true);
return getTypeLinkageAndVisibility(&T);
}
/// Get the most restrictive linkage for the types in the given
/// template parameter list. For visibility purposes, template
/// parameters are part of the signature of a template.
LinkageInfo LinkageComputer::getLVForTemplateParameterList(
const TemplateParameterList *Params, LVComputationKind computation) {
LinkageInfo LV;
for (const NamedDecl *P : *Params) {
// Template type parameters are the most common and never
// contribute to visibility, pack or not.
if (isa<TemplateTypeParmDecl>(P))
continue;
// Non-type template parameters can be restricted by the value type, e.g.
// template <enum X> class A { ... };
// We have to be careful here, though, because we can be dealing with
// dependent types.
if (const auto *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
// Handle the non-pack case first.
if (!NTTP->isExpandedParameterPack()) {
if (!NTTP->getType()->isDependentType()) {
LV.merge(getLVForType(*NTTP->getType(), computation));
}
continue;
}
// Look at all the types in an expanded pack.
for (unsigned i = 0, n = NTTP->getNumExpansionTypes(); i != n; ++i) {
QualType type = NTTP->getExpansionType(i);
if (!type->isDependentType())
LV.merge(getTypeLinkageAndVisibility(type));
}
continue;
}
// Template template parameters can be restricted by their
// template parameters, recursively.
const auto *TTP = cast<TemplateTemplateParmDecl>(P);
// Handle the non-pack case first.
if (!TTP->isExpandedParameterPack()) {
LV.merge(getLVForTemplateParameterList(TTP->getTemplateParameters(),
computation));
continue;
}
// Look at all expansions in an expanded pack.
for (unsigned i = 0, n = TTP->getNumExpansionTemplateParameters();
i != n; ++i) {
LV.merge(getLVForTemplateParameterList(
TTP->getExpansionTemplateParameters(i), computation));
}
}
return LV;
}
static const Decl *getOutermostFuncOrBlockContext(const Decl *D) {
const Decl *Ret = nullptr;
const DeclContext *DC = D->getDeclContext();
while (DC->getDeclKind() != Decl::TranslationUnit) {
if (isa<FunctionDecl>(DC) || isa<BlockDecl>(DC))
Ret = cast<Decl>(DC);
DC = DC->getParent();
}
return Ret;
}
/// Get the most restrictive linkage for the types and
/// declarations in the given template argument list.
///
/// Note that we don't take an LVComputationKind because we always
/// want to honor the visibility of template arguments in the same way.
LinkageInfo
LinkageComputer::getLVForTemplateArgumentList(ArrayRef<TemplateArgument> Args,
LVComputationKind computation) {
LinkageInfo LV;
for (const TemplateArgument &Arg : Args) {
switch (Arg.getKind()) {
case TemplateArgument::Null:
case TemplateArgument::Integral:
case TemplateArgument::Expression:
continue;
case TemplateArgument::Type:
LV.merge(getLVForType(*Arg.getAsType(), computation));
continue;
case TemplateArgument::Declaration: {
const NamedDecl *ND = Arg.getAsDecl();
assert(!usesTypeVisibility(ND));
LV.merge(getLVForDecl(ND, computation));
continue;
}
case TemplateArgument::NullPtr:
LV.merge(getTypeLinkageAndVisibility(Arg.getNullPtrType()));
continue;
case TemplateArgument::Template:
case TemplateArgument::TemplateExpansion:
if (TemplateDecl *Template =
Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl())
LV.merge(getLVForDecl(Template, computation));
continue;
case TemplateArgument::Pack:
LV.merge(getLVForTemplateArgumentList(Arg.getPackAsArray(), computation));
continue;
}
llvm_unreachable("bad template argument kind");
}
return LV;
}
LinkageInfo
LinkageComputer::getLVForTemplateArgumentList(const TemplateArgumentList &TArgs,
LVComputationKind computation) {
return getLVForTemplateArgumentList(TArgs.asArray(), computation);
}
static bool shouldConsiderTemplateVisibility(const FunctionDecl *fn,
const FunctionTemplateSpecializationInfo *specInfo) {
// Include visibility from the template parameters and arguments
// only if this is not an explicit instantiation or specialization
// with direct explicit visibility. (Implicit instantiations won't
// have a direct attribute.)
if (!specInfo->isExplicitInstantiationOrSpecialization())
return true;
return !fn->hasAttr<VisibilityAttr>();
}
/// Merge in template-related linkage and visibility for the given
/// function template specialization.
///
/// We don't need a computation kind here because we can assume
/// LVForValue.
///
/// \param[out] LV the computation to use for the parent
void LinkageComputer::mergeTemplateLV(
LinkageInfo &LV, const FunctionDecl *fn,
const FunctionTemplateSpecializationInfo *specInfo,
LVComputationKind computation) {
bool considerVisibility =
shouldConsiderTemplateVisibility(fn, specInfo);
// Merge information from the template parameters.
FunctionTemplateDecl *temp = specInfo->getTemplate();
LinkageInfo tempLV =
getLVForTemplateParameterList(temp->getTemplateParameters(), computation);
LV.mergeMaybeWithVisibility(tempLV, considerVisibility);
// Merge information from the template arguments.
const TemplateArgumentList &templateArgs = *specInfo->TemplateArguments;
LinkageInfo argsLV = getLVForTemplateArgumentList(templateArgs, computation);
LV.mergeMaybeWithVisibility(argsLV, considerVisibility);
}
/// Does the given declaration have a direct visibility attribute
/// that would match the given rules?
static bool hasDirectVisibilityAttribute(const NamedDecl *D,
LVComputationKind computation) {
if (computation.IgnoreAllVisibility)
return false;
return (computation.isTypeVisibility() && D->hasAttr<TypeVisibilityAttr>()) ||
D->hasAttr<VisibilityAttr>();
}
/// Should we consider visibility associated with the template
/// arguments and parameters of the given class template specialization?
static bool shouldConsiderTemplateVisibility(
const ClassTemplateSpecializationDecl *spec,
LVComputationKind computation) {
// Include visibility from the template parameters and arguments
// only if this is not an explicit instantiation or specialization
// with direct explicit visibility (and note that implicit
// instantiations won't have a direct attribute).
//
// Furthermore, we want to ignore template parameters and arguments
// for an explicit specialization when computing the visibility of a
// member thereof with explicit visibility.
//
// This is a bit complex; let's unpack it.
//
// An explicit class specialization is an independent, top-level
// declaration. As such, if it or any of its members has an
// explicit visibility attribute, that must directly express the
// user's intent, and we should honor it. The same logic applies to
// an explicit instantiation of a member of such a thing.
// Fast path: if this is not an explicit instantiation or
// specialization, we always want to consider template-related
// visibility restrictions.
if (!spec->isExplicitInstantiationOrSpecialization())
return true;
// This is the 'member thereof' check.
if (spec->isExplicitSpecialization() &&
hasExplicitVisibilityAlready(computation))
return false;
return !hasDirectVisibilityAttribute(spec, computation);
}
/// Merge in template-related linkage and visibility for the given
/// class template specialization.
void LinkageComputer::mergeTemplateLV(
LinkageInfo &LV, const ClassTemplateSpecializationDecl *spec,
LVComputationKind computation) {
bool considerVisibility = shouldConsiderTemplateVisibility(spec, computation);
// Merge information from the template parameters, but ignore
// visibility if we're only considering template arguments.
ClassTemplateDecl *temp = spec->getSpecializedTemplate();
LinkageInfo tempLV =
getLVForTemplateParameterList(temp->getTemplateParameters(), computation);
LV.mergeMaybeWithVisibility(tempLV,
considerVisibility && !hasExplicitVisibilityAlready(computation));
// Merge information from the template arguments. We ignore
// template-argument visibility if we've got an explicit
// instantiation with a visibility attribute.
const TemplateArgumentList &templateArgs = spec->getTemplateArgs();
LinkageInfo argsLV = getLVForTemplateArgumentList(templateArgs, computation);
if (considerVisibility)
LV.mergeVisibility(argsLV);
LV.mergeExternalVisibility(argsLV);
}
/// Should we consider visibility associated with the template
/// arguments and parameters of the given variable template
/// specialization? As usual, follow class template specialization
/// logic up to initialization.
static bool shouldConsiderTemplateVisibility(
const VarTemplateSpecializationDecl *spec,
LVComputationKind computation) {
// Include visibility from the template parameters and arguments
// only if this is not an explicit instantiation or specialization
// with direct explicit visibility (and note that implicit
// instantiations won't have a direct attribute).
if (!spec->isExplicitInstantiationOrSpecialization())
return true;
// An explicit variable specialization is an independent, top-level
// declaration. As such, if it has an explicit visibility attribute,
// that must directly express the user's intent, and we should honor
// it.
if (spec->isExplicitSpecialization() &&
hasExplicitVisibilityAlready(computation))
return false;
return !hasDirectVisibilityAttribute(spec, computation);
}
/// Merge in template-related linkage and visibility for the given
/// variable template specialization. As usual, follow class template
/// specialization logic up to initialization.
void LinkageComputer::mergeTemplateLV(LinkageInfo &LV,
const VarTemplateSpecializationDecl *spec,
LVComputationKind computation) {
bool considerVisibility = shouldConsiderTemplateVisibility(spec, computation);
// Merge information from the template parameters, but ignore
// visibility if we're only considering template arguments.
VarTemplateDecl *temp = spec->getSpecializedTemplate();
LinkageInfo tempLV =
getLVForTemplateParameterList(temp->getTemplateParameters(), computation);
LV.mergeMaybeWithVisibility(tempLV,
considerVisibility && !hasExplicitVisibilityAlready(computation));
// Merge information from the template arguments. We ignore
// template-argument visibility if we've got an explicit
// instantiation with a visibility attribute.
const TemplateArgumentList &templateArgs = spec->getTemplateArgs();
LinkageInfo argsLV = getLVForTemplateArgumentList(templateArgs, computation);
if (considerVisibility)
LV.mergeVisibility(argsLV);
LV.mergeExternalVisibility(argsLV);
}
static bool useInlineVisibilityHidden(const NamedDecl *D) {
// FIXME: we should warn if -fvisibility-inlines-hidden is used with c.
const LangOptions &Opts = D->getASTContext().getLangOpts();
if (!Opts.CPlusPlus || !Opts.InlineVisibilityHidden)
return false;
const auto *FD = dyn_cast<FunctionDecl>(D);
if (!FD)
return false;
TemplateSpecializationKind TSK = TSK_Undeclared;
if (FunctionTemplateSpecializationInfo *spec
= FD->getTemplateSpecializationInfo()) {
TSK = spec->getTemplateSpecializationKind();
} else if (MemberSpecializationInfo *MSI =
FD->getMemberSpecializationInfo()) {
TSK = MSI->getTemplateSpecializationKind();
}
const FunctionDecl *Def = nullptr;
// InlineVisibilityHidden only applies to definitions, and
// isInlined() only gives meaningful answers on definitions
// anyway.
return TSK != TSK_ExplicitInstantiationDeclaration &&
TSK != TSK_ExplicitInstantiationDefinition &&
FD->hasBody(Def) && Def->isInlined() && !Def->hasAttr<GNUInlineAttr>();
}
template <typename T> static bool isFirstInExternCContext(T *D) {
const T *First = D->getFirstDecl();
return First->isInExternCContext();
}
static bool isSingleLineLanguageLinkage(const Decl &D) {
if (const auto *SD = dyn_cast<LinkageSpecDecl>(D.getDeclContext()))
if (!SD->hasBraces())
return true;
return false;
}
/// Determine whether D is declared in the purview of a named module.
static bool isInModulePurview(const NamedDecl *D) {
if (auto *M = D->getOwningModule())
return M->isModulePurview();
return false;
}
static bool isExportedFromModuleInterfaceUnit(const NamedDecl *D) {
// FIXME: Handle isModulePrivate.
switch (D->getModuleOwnershipKind()) {
case Decl::ModuleOwnershipKind::Unowned:
case Decl::ModuleOwnershipKind::ModulePrivate:
return false;
case Decl::ModuleOwnershipKind::Visible:
case Decl::ModuleOwnershipKind::VisibleWhenImported:
return isInModulePurview(D);
}
llvm_unreachable("unexpected module ownership kind");
}
static LinkageInfo getInternalLinkageFor(const NamedDecl *D) {
// Internal linkage declarations within a module interface unit are modeled
// as "module-internal linkage", which means that they have internal linkage
// formally but can be indirectly accessed from outside the module via inline
// functions and templates defined within the module.
if (isInModulePurview(D))
return LinkageInfo(ModuleInternalLinkage, DefaultVisibility, false);
return LinkageInfo::internal();
}
static LinkageInfo getExternalLinkageFor(const NamedDecl *D) {
// C++ Modules TS [basic.link]/6.8:
// - A name declared at namespace scope that does not have internal linkage
// by the previous rules and that is introduced by a non-exported
// declaration has module linkage.
if (isInModulePurview(D) && !isExportedFromModuleInterfaceUnit(
cast<NamedDecl>(D->getCanonicalDecl())))
return LinkageInfo(ModuleLinkage, DefaultVisibility, false);
return LinkageInfo::external();
}
static StorageClass getStorageClass(const Decl *D) {
if (auto *TD = dyn_cast<TemplateDecl>(D))
D = TD->getTemplatedDecl();
if (D) {
if (auto *VD = dyn_cast<VarDecl>(D))
return VD->getStorageClass();
if (auto *FD = dyn_cast<FunctionDecl>(D))
return FD->getStorageClass();
}
return SC_None;
}
LinkageInfo
LinkageComputer::getLVForNamespaceScopeDecl(const NamedDecl *D,
LVComputationKind computation,
bool IgnoreVarTypeLinkage) {
assert(D->getDeclContext()->getRedeclContext()->isFileContext() &&
"Not a name having namespace scope");
ASTContext &Context = D->getASTContext();
// C++ [basic.link]p3:
// A name having namespace scope (3.3.6) has internal linkage if it
// is the name of
if (getStorageClass(D->getCanonicalDecl()) == SC_Static) {
// - a variable, variable template, function, or function template
// that is explicitly declared static; or
// (This bullet corresponds to C99 6.2.2p3.)
return getInternalLinkageFor(D);
}
if (const auto *Var = dyn_cast<VarDecl>(D)) {
// - a non-template variable of non-volatile const-qualified type, unless
// - it is explicitly declared extern, or
// - it is inline or exported, or
// - it was previously declared and the prior declaration did not have
// internal linkage
// (There is no equivalent in C99.)
if (Context.getLangOpts().CPlusPlus &&
Var->getType().isConstQualified() &&
!Var->getType().isVolatileQualified() &&
!Var->isInline() &&
!isExportedFromModuleInterfaceUnit(Var) &&
!isa<VarTemplateSpecializationDecl>(Var) &&
!Var->getDescribedVarTemplate()) {
const VarDecl *PrevVar = Var->getPreviousDecl();
if (PrevVar)
return getLVForDecl(PrevVar, computation);
if (Var->getStorageClass() != SC_Extern &&
Var->getStorageClass() != SC_PrivateExtern &&
!isSingleLineLanguageLinkage(*Var))
return getInternalLinkageFor(Var);
}
for (const VarDecl *PrevVar = Var->getPreviousDecl(); PrevVar;
PrevVar = PrevVar->getPreviousDecl()) {
if (PrevVar->getStorageClass() == SC_PrivateExtern &&
Var->getStorageClass() == SC_None)
return getDeclLinkageAndVisibility(PrevVar);
// Explicitly declared static.
if (PrevVar->getStorageClass() == SC_Static)
return getInternalLinkageFor(Var);
}
} else if (const auto *IFD = dyn_cast<IndirectFieldDecl>(D)) {
// - a data member of an anonymous union.
const VarDecl *VD = IFD->getVarDecl();
assert(VD && "Expected a VarDecl in this IndirectFieldDecl!");
return getLVForNamespaceScopeDecl(VD, computation, IgnoreVarTypeLinkage);
}
assert(!isa<FieldDecl>(D) && "Didn't expect a FieldDecl!");
// FIXME: This gives internal linkage to names that should have no linkage
// (those not covered by [basic.link]p6).
if (D->isInAnonymousNamespace()) {
const auto *Var = dyn_cast<VarDecl>(D);
const auto *Func = dyn_cast<FunctionDecl>(D);
// FIXME: The check for extern "C" here is not justified by the standard
// wording, but we retain it from the pre-DR1113 model to avoid breaking
// code.
//
// C++11 [basic.link]p4:
// An unnamed namespace or a namespace declared directly or indirectly
// within an unnamed namespace has internal linkage.
if ((!Var || !isFirstInExternCContext(Var)) &&
(!Func || !isFirstInExternCContext(Func)))
return getInternalLinkageFor(D);
}
// Set up the defaults.
// C99 6.2.2p5:
// If the declaration of an identifier for an object has file
// scope and no storage-class specifier, its linkage is
// external.
LinkageInfo LV = getExternalLinkageFor(D);
if (!hasExplicitVisibilityAlready(computation)) {
if (Optional<Visibility> Vis = getExplicitVisibility(D, computation)) {
LV.mergeVisibility(*Vis, true);
} else {
// If we're declared in a namespace with a visibility attribute,
// use that namespace's visibility, and it still counts as explicit.
for (const DeclContext *DC = D->getDeclContext();
!isa<TranslationUnitDecl>(DC);
DC = DC->getParent()) {
const auto *ND = dyn_cast<NamespaceDecl>(DC);
if (!ND) continue;
if (Optional<Visibility> Vis = getExplicitVisibility(ND, computation)) {
LV.mergeVisibility(*Vis, true);
break;
}
}
}
// Add in global settings if the above didn't give us direct visibility.
if (!LV.isVisibilityExplicit()) {
// Use global type/value visibility as appropriate.
Visibility globalVisibility =
computation.isValueVisibility()
? Context.getLangOpts().getValueVisibilityMode()
: Context.getLangOpts().getTypeVisibilityMode();
LV.mergeVisibility(globalVisibility, /*explicit*/ false);
// If we're paying attention to global visibility, apply
// -finline-visibility-hidden if this is an inline method.
if (useInlineVisibilityHidden(D))
LV.mergeVisibility(HiddenVisibility, /*visibilityExplicit=*/false);
}
}
// C++ [basic.link]p4:
// A name having namespace scope that has not been given internal linkage
// above and that is the name of
// [...bullets...]
// has its linkage determined as follows:
// - if the enclosing namespace has internal linkage, the name has
// internal linkage; [handled above]
// - otherwise, if the declaration of the name is attached to a named
// module and is not exported, the name has module linkage;
// - otherwise, the name has external linkage.
// LV is currently set up to handle the last two bullets.
//
// The bullets are:
// - a variable; or
if (const auto *Var = dyn_cast<VarDecl>(D)) {
// GCC applies the following optimization to variables and static
// data members, but not to functions:
//
// Modify the variable's LV by the LV of its type unless this is
// C or extern "C". This follows from [basic.link]p9:
// A type without linkage shall not be used as the type of a
// variable or function with external linkage unless
// - the entity has C language linkage, or
// - the entity is declared within an unnamed namespace, or
// - the entity is not used or is defined in the same
// translation unit.
// and [basic.link]p10:
// ...the types specified by all declarations referring to a
// given variable or function shall be identical...
// C does not have an equivalent rule.
//
// Ignore this if we've got an explicit attribute; the user
// probably knows what they're doing.
//
// Note that we don't want to make the variable non-external
// because of this, but unique-external linkage suits us.
if (Context.getLangOpts().CPlusPlus && !isFirstInExternCContext(Var) &&
!IgnoreVarTypeLinkage) {
LinkageInfo TypeLV = getLVForType(*Var->getType(), computation);
if (!isExternallyVisible(TypeLV.getLinkage()))
return LinkageInfo::uniqueExternal();
if (!LV.isVisibilityExplicit())
LV.mergeVisibility(TypeLV);
}
if (Var->getStorageClass() == SC_PrivateExtern)
LV.mergeVisibility(HiddenVisibility, true);
// Note that Sema::MergeVarDecl already takes care of implementing
// C99 6.2.2p4 and propagating the visibility attribute, so we don't have
// to do it here.
// As per function and class template specializations (below),
// consider LV for the template and template arguments. We're at file
// scope, so we do not need to worry about nested specializations.
if (const auto *spec = dyn_cast<VarTemplateSpecializationDecl>(Var)) {
mergeTemplateLV(LV, spec, computation);
}
// - a function; or
} else if (const auto *Function = dyn_cast<FunctionDecl>(D)) {
// In theory, we can modify the function's LV by the LV of its
// type unless it has C linkage (see comment above about variables
// for justification). In practice, GCC doesn't do this, so it's
// just too painful to make work.
if (Function->getStorageClass() == SC_PrivateExtern)
LV.mergeVisibility(HiddenVisibility, true);
// Note that Sema::MergeCompatibleFunctionDecls already takes care of
// merging storage classes and visibility attributes, so we don't have to
// look at previous decls in here.
// In C++, then if the type of the function uses a type with
// unique-external linkage, it's not legally usable from outside
// this translation unit. However, we should use the C linkage
// rules instead for extern "C" declarations.
if (Context.getLangOpts().CPlusPlus && !isFirstInExternCContext(Function)) {
// Only look at the type-as-written. Otherwise, deducing the return type
// of a function could change its linkage.
QualType TypeAsWritten = Function->getType();
if (TypeSourceInfo *TSI = Function->getTypeSourceInfo())
TypeAsWritten = TSI->getType();
if (!isExternallyVisible(TypeAsWritten->getLinkage()))
return LinkageInfo::uniqueExternal();
}
// Consider LV from the template and the template arguments.
// We're at file scope, so we do not need to worry about nested
// specializations.
if (FunctionTemplateSpecializationInfo *specInfo
= Function->getTemplateSpecializationInfo()) {
mergeTemplateLV(LV, Function, specInfo, computation);
}
// - a named class (Clause 9), or an unnamed class defined in a
// typedef declaration in which the class has the typedef name
// for linkage purposes (7.1.3); or
// - a named enumeration (7.2), or an unnamed enumeration
// defined in a typedef declaration in which the enumeration
// has the typedef name for linkage purposes (7.1.3); or
} else if (const auto *Tag = dyn_cast<TagDecl>(D)) {
// Unnamed tags have no linkage.
if (!Tag->hasNameForLinkage())
return LinkageInfo::none();
// If this is a class template specialization, consider the
// linkage of the template and template arguments. We're at file
// scope, so we do not need to worry about nested specializations.
if (const auto *spec = dyn_cast<ClassTemplateSpecializationDecl>(Tag)) {
mergeTemplateLV(LV, spec, computation);
}
// FIXME: This is not part of the C++ standard any more.
// - an enumerator belonging to an enumeration with external linkage; or
} else if (isa<EnumConstantDecl>(D)) {
LinkageInfo EnumLV = getLVForDecl(cast<NamedDecl>(D->getDeclContext()),
computation);
if (!isExternalFormalLinkage(EnumLV.getLinkage()))
return LinkageInfo::none();
LV.merge(EnumLV);
// - a template
} else if (const auto *temp = dyn_cast<TemplateDecl>(D)) {
bool considerVisibility = !hasExplicitVisibilityAlready(computation);
LinkageInfo tempLV =
getLVForTemplateParameterList(temp->getTemplateParameters(), computation);
LV.mergeMaybeWithVisibility(tempLV, considerVisibility);
// An unnamed namespace or a namespace declared directly or indirectly
// within an unnamed namespace has internal linkage. All other namespaces
// have external linkage.
//
// We handled names in anonymous namespaces above.
} else if (isa<NamespaceDecl>(D)) {
return LV;
// By extension, we assign external linkage to Objective-C
// interfaces.
} else if (isa<ObjCInterfaceDecl>(D)) {
// fallout
} else if (auto *TD = dyn_cast<TypedefNameDecl>(D)) {
// A typedef declaration has linkage if it gives a type a name for
// linkage purposes.
if (!TD->getAnonDeclWithTypedefName(/*AnyRedecl*/true))
return LinkageInfo::none();
// Everything not covered here has no linkage.
} else {
return LinkageInfo::none();
}
// If we ended up with non-externally-visible linkage, visibility should
// always be default.
if (!isExternallyVisible(LV.getLinkage()))
return LinkageInfo(LV.getLinkage(), DefaultVisibility, false);
return LV;
}
LinkageInfo
LinkageComputer::getLVForClassMember(const NamedDecl *D,
LVComputationKind computation,
bool IgnoreVarTypeLinkage) {
// Only certain class members have linkage. Note that fields don't
// really have linkage, but it's convenient to say they do for the
// purposes of calculating linkage of pointer-to-data-member
// template arguments.
//
// Templates also don't officially have linkage, but since we ignore
// the C++ standard and look at template arguments when determining
// linkage and visibility of a template specialization, we might hit
// a template template argument that way. If we do, we need to
// consider its linkage.
if (!(isa<CXXMethodDecl>(D) ||
isa<VarDecl>(D) ||
isa<FieldDecl>(D) ||
isa<IndirectFieldDecl>(D) ||
isa<TagDecl>(D) ||
isa<TemplateDecl>(D)))
return LinkageInfo::none();
LinkageInfo LV;
// If we have an explicit visibility attribute, merge that in.
if (!hasExplicitVisibilityAlready(computation)) {
if (Optional<Visibility> Vis = getExplicitVisibility(D, computation))
LV.mergeVisibility(*Vis, true);
// If we're paying attention to global visibility, apply
// -finline-visibility-hidden if this is an inline method.
//
// Note that we do this before merging information about
// the class visibility.
if (!LV.isVisibilityExplicit() && useInlineVisibilityHidden(D))
LV.mergeVisibility(HiddenVisibility, /*visibilityExplicit=*/false);
}
// If this class member has an explicit visibility attribute, the only
// thing that can change its visibility is the template arguments, so
// only look for them when processing the class.
LVComputationKind classComputation = computation;
if (LV.isVisibilityExplicit())
classComputation = withExplicitVisibilityAlready(computation);
LinkageInfo classLV =
getLVForDecl(cast<RecordDecl>(D->getDeclContext()), classComputation);
// The member has the same linkage as the class. If that's not externally
// visible, we don't need to compute anything about the linkage.
// FIXME: If we're only computing linkage, can we bail out here?
if (!isExternallyVisible(classLV.getLinkage()))
return classLV;
// Otherwise, don't merge in classLV yet, because in certain cases
// we need to completely ignore the visibility from it.
// Specifically, if this decl exists and has an explicit attribute.
const NamedDecl *explicitSpecSuppressor = nullptr;
if (const auto *MD = dyn_cast<CXXMethodDecl>(D)) {
// Only look at the type-as-written. Otherwise, deducing the return type
// of a function could change its linkage.
QualType TypeAsWritten = MD->getType();
if (TypeSourceInfo *TSI = MD->getTypeSourceInfo())
TypeAsWritten = TSI->getType();
if (!isExternallyVisible(TypeAsWritten->getLinkage()))
return LinkageInfo::uniqueExternal();
// If this is a method template specialization, use the linkage for
// the template parameters and arguments.
if (FunctionTemplateSpecializationInfo *spec
= MD->getTemplateSpecializationInfo()) {
mergeTemplateLV(LV, MD, spec, computation);
if (spec->isExplicitSpecialization()) {
explicitSpecSuppressor = MD;
} else if (isExplicitMemberSpecialization(spec->getTemplate())) {
explicitSpecSuppressor = spec->getTemplate()->getTemplatedDecl();
}
} else if (isExplicitMemberSpecialization(MD)) {
explicitSpecSuppressor = MD;
}
} else if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
if (const auto *spec = dyn_cast<ClassTemplateSpecializationDecl>(RD)) {
mergeTemplateLV(LV, spec, computation);
if (spec->isExplicitSpecialization()) {
explicitSpecSuppressor = spec;
} else {
const ClassTemplateDecl *temp = spec->getSpecializedTemplate();
if (isExplicitMemberSpecialization(temp)) {
explicitSpecSuppressor = temp->getTemplatedDecl();
}
}
} else if (isExplicitMemberSpecialization(RD)) {
explicitSpecSuppressor = RD;
}
// Static data members.
} else if (const auto *VD = dyn_cast<VarDecl>(D)) {
if (const auto *spec = dyn_cast<VarTemplateSpecializationDecl>(VD))
mergeTemplateLV(LV, spec, computation);
// Modify the variable's linkage by its type, but ignore the
// type's visibility unless it's a definition.
if (!IgnoreVarTypeLinkage) {
LinkageInfo typeLV = getLVForType(*VD->getType(), computation);
// FIXME: If the type's linkage is not externally visible, we can
// give this static data member UniqueExternalLinkage.
if (!LV.isVisibilityExplicit() && !classLV.isVisibilityExplicit())
LV.mergeVisibility(typeLV);
LV.mergeExternalVisibility(typeLV);
}
if (isExplicitMemberSpecialization(VD)) {
explicitSpecSuppressor = VD;
}
// Template members.
} else if (const auto *temp = dyn_cast<TemplateDecl>(D)) {
bool considerVisibility =
(!LV.isVisibilityExplicit() &&
!classLV.isVisibilityExplicit() &&
!hasExplicitVisibilityAlready(computation));
LinkageInfo tempLV =
getLVForTemplateParameterList(temp->getTemplateParameters(), computation);
LV.mergeMaybeWithVisibility(tempLV, considerVisibility);
if (const auto *redeclTemp = dyn_cast<RedeclarableTemplateDecl>(temp)) {
if (isExplicitMemberSpecialization(redeclTemp)) {
explicitSpecSuppressor = temp->getTemplatedDecl();
}
}
}
// We should never be looking for an attribute directly on a template.
assert(!explicitSpecSuppressor || !isa<TemplateDecl>(explicitSpecSuppressor));
// If this member is an explicit member specialization, and it has
// an explicit attribute, ignore visibility from the parent.
bool considerClassVisibility = true;
if (explicitSpecSuppressor &&
// optimization: hasDVA() is true only with explicit visibility.
LV.isVisibilityExplicit() &&
classLV.getVisibility() != DefaultVisibility &&
hasDirectVisibilityAttribute(explicitSpecSuppressor, computation)) {
considerClassVisibility = false;
}
// Finally, merge in information from the class.
LV.mergeMaybeWithVisibility(classLV, considerClassVisibility);
return LV;
}
void NamedDecl::anchor() {}
bool NamedDecl::isLinkageValid() const {
if (!hasCachedLinkage())
return true;
Linkage L = LinkageComputer{}
.computeLVForDecl(this, LVComputationKind::forLinkageOnly())
.getLinkage();
return L == getCachedLinkage();
}
ObjCStringFormatFamily NamedDecl::getObjCFStringFormattingFamily() const {
StringRef name = getName();
if (name.empty()) return SFF_None;
if (name.front() == 'C')
if (name == "CFStringCreateWithFormat" ||
name == "CFStringCreateWithFormatAndArguments" ||
name == "CFStringAppendFormat" ||
name == "CFStringAppendFormatAndArguments")
return SFF_CFString;
return SFF_None;
}
Linkage NamedDecl::getLinkageInternal() const {
// We don't care about visibility here, so ask for the cheapest
// possible visibility analysis.
return LinkageComputer{}
.getLVForDecl(this, LVComputationKind::forLinkageOnly())
.getLinkage();
}
LinkageInfo NamedDecl::getLinkageAndVisibility() const {
return LinkageComputer{}.getDeclLinkageAndVisibility(this);
}
static Optional<Visibility>
getExplicitVisibilityAux(const NamedDecl *ND,
NamedDecl::ExplicitVisibilityKind kind,
bool IsMostRecent) {
assert(!IsMostRecent || ND == ND->getMostRecentDecl());
// Check the declaration itself first.
if (Optional<Visibility> V = getVisibilityOf(ND, kind))
return V;
// If this is a member class of a specialization of a class template
// and the corresponding decl has explicit visibility, use that.
if (const auto *RD = dyn_cast<CXXRecordDecl>(ND)) {
CXXRecordDecl *InstantiatedFrom = RD->getInstantiatedFromMemberClass();
if (InstantiatedFrom)
return getVisibilityOf(InstantiatedFrom, kind);
}
// If there wasn't explicit visibility there, and this is a
// specialization of a class template, check for visibility
// on the pattern.
if (const auto *spec = dyn_cast<ClassTemplateSpecializationDecl>(ND)) {
// Walk all the template decl till this point to see if there are
// explicit visibility attributes.
const auto *TD = spec->getSpecializedTemplate()->getTemplatedDecl();
while (TD != nullptr) {
auto Vis = getVisibilityOf(TD, kind);
if (Vis != None)
return Vis;
TD = TD->getPreviousDecl();
}
return None;
}
// Use the most recent declaration.
if (!IsMostRecent && !isa<NamespaceDecl>(ND)) {
const NamedDecl *MostRecent = ND->getMostRecentDecl();
if (MostRecent != ND)
return getExplicitVisibilityAux(MostRecent, kind, true);
}
if (const auto *Var = dyn_cast<VarDecl>(ND)) {
if (Var->isStaticDataMember()) {
VarDecl *InstantiatedFrom = Var->getInstantiatedFromStaticDataMember();
if (InstantiatedFrom)
return getVisibilityOf(InstantiatedFrom, kind);
}
if (const auto *VTSD = dyn_cast<VarTemplateSpecializationDecl>(Var))
return getVisibilityOf(VTSD->getSpecializedTemplate()->getTemplatedDecl(),
kind);
return None;
}
// Also handle function template specializations.
if (const auto *fn = dyn_cast<FunctionDecl>(ND)) {
// If the function is a specialization of a template with an
// explicit visibility attribute, use that.
if (FunctionTemplateSpecializationInfo *templateInfo
= fn->getTemplateSpecializationInfo())
return getVisibilityOf(templateInfo->getTemplate()->getTemplatedDecl(),
kind);
// If the function is a member of a specialization of a class template
// and the corresponding decl has explicit visibility, use that.
FunctionDecl *InstantiatedFrom = fn->getInstantiatedFromMemberFunction();
if (InstantiatedFrom)
return getVisibilityOf(InstantiatedFrom, kind);
return None;
}
// The visibility of a template is stored in the templated decl.
if (const auto *TD = dyn_cast<TemplateDecl>(ND))
return getVisibilityOf(TD->getTemplatedDecl(), kind);
return None;
}
Optional<Visibility>
NamedDecl::getExplicitVisibility(ExplicitVisibilityKind kind) const {
return getExplicitVisibilityAux(this, kind, false);
}
LinkageInfo LinkageComputer::getLVForClosure(const DeclContext *DC,
Decl *ContextDecl,
LVComputationKind computation) {
// This lambda has its linkage/visibility determined by its owner.
const NamedDecl *Owner;
if (!ContextDecl)
Owner = dyn_cast<NamedDecl>(DC);
else if (isa<ParmVarDecl>(ContextDecl))
Owner =
dyn_cast<NamedDecl>(ContextDecl->getDeclContext()->getRedeclContext());
else
Owner = cast<NamedDecl>(ContextDecl);
if (!Owner)
return LinkageInfo::none();
// If the owner has a deduced type, we need to skip querying the linkage and
// visibility of that type, because it might involve this closure type. The
// only effect of this is that we might give a lambda VisibleNoLinkage rather
// than NoLinkage when we don't strictly need to, which is benign.
auto *VD = dyn_cast<VarDecl>(Owner);
LinkageInfo OwnerLV =
VD && VD->getType()->getContainedDeducedType()
? computeLVForDecl(Owner, computation, /*IgnoreVarTypeLinkage*/true)
: getLVForDecl(Owner, computation);
// A lambda never formally has linkage. But if the owner is externally
// visible, then the lambda is too. We apply the same rules to blocks.
if (!isExternallyVisible(OwnerLV.getLinkage()))
return LinkageInfo::none();
return LinkageInfo(VisibleNoLinkage, OwnerLV.getVisibility(),
OwnerLV.isVisibilityExplicit());
}
LinkageInfo LinkageComputer::getLVForLocalDecl(const NamedDecl *D,
LVComputationKind computation) {
if (const auto *Function = dyn_cast<FunctionDecl>(D)) {
if (Function->isInAnonymousNamespace() &&
!isFirstInExternCContext(Function))
return getInternalLinkageFor(Function);
// This is a "void f();" which got merged with a file static.
if (Function->getCanonicalDecl()->getStorageClass() == SC_Static)
return getInternalLinkageFor(Function);
LinkageInfo LV;
if (!hasExplicitVisibilityAlready(computation)) {
if (Optional<Visibility> Vis =
getExplicitVisibility(Function, computation))
LV.mergeVisibility(*Vis, true);
}
// Note that Sema::MergeCompatibleFunctionDecls already takes care of
// merging storage classes and visibility attributes, so we don't have to
// look at previous decls in here.
return LV;
}
if (const auto *Var = dyn_cast<VarDecl>(D)) {
if (Var->hasExternalStorage()) {
if (Var->isInAnonymousNamespace() && !isFirstInExternCContext(Var))
return getInternalLinkageFor(Var);
LinkageInfo LV;
if (Var->getStorageClass() == SC_PrivateExtern)
LV.mergeVisibility(HiddenVisibility, true);
else if (!hasExplicitVisibilityAlready(computation)) {
if (Optional<Visibility> Vis = getExplicitVisibility(Var, computation))
LV.mergeVisibility(*Vis, true);
}
if (const VarDecl *Prev = Var->getPreviousDecl()) {
LinkageInfo PrevLV = getLVForDecl(Prev, computation);
if (PrevLV.getLinkage())
LV.setLinkage(PrevLV.getLinkage());
LV.mergeVisibility(PrevLV);
}
return LV;
}
if (!Var->isStaticLocal())
return LinkageInfo::none();
}
ASTContext &Context = D->getASTContext();
if (!Context.getLangOpts().CPlusPlus)
return LinkageInfo::none();
const Decl *OuterD = getOutermostFuncOrBlockContext(D);
if (!OuterD || OuterD->isInvalidDecl())
return LinkageInfo::none();
LinkageInfo LV;
if (const auto *BD = dyn_cast<BlockDecl>(OuterD)) {
if (!BD->getBlockManglingNumber())
return LinkageInfo::none();
LV = getLVForClosure(BD->getDeclContext()->getRedeclContext(),
BD->getBlockManglingContextDecl(), computation);
} else {
const auto *FD = cast<FunctionDecl>(OuterD);
if (!FD->isInlined() &&
!isTemplateInstantiation(FD->getTemplateSpecializationKind()))
return LinkageInfo::none();
// If a function is hidden by -fvisibility-inlines-hidden option and
// is not explicitly attributed as a hidden function,
// we should not make static local variables in the function hidden.
LV = getLVForDecl(FD, computation);
if (isa<VarDecl>(D) && useInlineVisibilityHidden(FD) &&
!LV.isVisibilityExplicit()) {
assert(cast<VarDecl>(D)->isStaticLocal());
// If this was an implicitly hidden inline method, check again for
// explicit visibility on the parent class, and use that for static locals
// if present.
if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
LV = getLVForDecl(MD->getParent(), computation);
if (!LV.isVisibilityExplicit()) {
Visibility globalVisibility =
computation.isValueVisibility()
? Context.getLangOpts().getValueVisibilityMode()
: Context.getLangOpts().getTypeVisibilityMode();
return LinkageInfo(VisibleNoLinkage, globalVisibility,
/*visibilityExplicit=*/false);
}
}
}
if (!isExternallyVisible(LV.getLinkage()))
return LinkageInfo::none();
return LinkageInfo(VisibleNoLinkage, LV.getVisibility(),
LV.isVisibilityExplicit());
}
static inline const CXXRecordDecl*
getOutermostEnclosingLambda(const CXXRecordDecl *Record) {
const CXXRecordDecl *Ret = Record;
while (Record && Record->isLambda()) {
Ret = Record;
if (!Record->getParent()) break;
// Get the Containing Class of this Lambda Class
Record = dyn_cast_or_null<CXXRecordDecl>(
Record->getParent()->getParent());
}
return Ret;
}
LinkageInfo LinkageComputer::computeLVForDecl(const NamedDecl *D,
LVComputationKind computation,
bool IgnoreVarTypeLinkage) {
// Internal_linkage attribute overrides other considerations.
if (D->hasAttr<InternalLinkageAttr>())
return getInternalLinkageFor(D);
// Objective-C: treat all Objective-C declarations as having external
// linkage.
switch (D->getKind()) {
default:
break;
// Per C++ [basic.link]p2, only the names of objects, references,
// functions, types, templates, namespaces, and values ever have linkage.
//
// Note that the name of a typedef, namespace alias, using declaration,
// and so on are not the name of the corresponding type, namespace, or
// declaration, so they do *not* have linkage.
case Decl::ImplicitParam:
case Decl::Label:
case Decl::NamespaceAlias:
case Decl::ParmVar:
case Decl::Using:
case Decl::UsingShadow:
case Decl::UsingDirective:
return LinkageInfo::none();
case Decl::EnumConstant:
// C++ [basic.link]p4: an enumerator has the linkage of its enumeration.
if (D->getASTContext().getLangOpts().CPlusPlus)
return getLVForDecl(cast<EnumDecl>(D->getDeclContext()), computation);
return LinkageInfo::visible_none();
case Decl::Typedef:
case Decl::TypeAlias:
// A typedef declaration has linkage if it gives a type a name for
// linkage purposes.
if (!cast<TypedefNameDecl>(D)
->getAnonDeclWithTypedefName(/*AnyRedecl*/true))
return LinkageInfo::none();
break;
case Decl::TemplateTemplateParm: // count these as external
case Decl::NonTypeTemplateParm:
case Decl::ObjCAtDefsField:
case Decl::ObjCCategory:
case Decl::ObjCCategoryImpl:
case Decl::ObjCCompatibleAlias:
case Decl::ObjCImplementation:
case Decl::ObjCMethod:
case Decl::ObjCProperty:
case Decl::ObjCPropertyImpl:
case Decl::ObjCProtocol:
return getExternalLinkageFor(D);
case Decl::CXXRecord: {
const auto *Record = cast<CXXRecordDecl>(D);
if (Record->isLambda()) {
if (!Record->getLambdaManglingNumber()) {
// This lambda has no mangling number, so it's internal.
return getInternalLinkageFor(D);
}
// This lambda has its linkage/visibility determined:
// - either by the outermost lambda if that lambda has no mangling
// number.
// - or by the parent of the outer most lambda
// This prevents infinite recursion in settings such as nested lambdas
// used in NSDMI's, for e.g.
// struct L {
// int t{};
// int t2 = ([](int a) { return [](int b) { return b; };})(t)(t);
// };
const CXXRecordDecl *OuterMostLambda =
getOutermostEnclosingLambda(Record);
if (!OuterMostLambda->getLambdaManglingNumber())
return getInternalLinkageFor(D);
return getLVForClosure(
OuterMostLambda->getDeclContext()->getRedeclContext(),
OuterMostLambda->getLambdaContextDecl(), computation);
}
break;
}
}
// Handle linkage for namespace-scope names.
if (D->getDeclContext()->getRedeclContext()->isFileContext())
return getLVForNamespaceScopeDecl(D, computation, IgnoreVarTypeLinkage);
// C++ [basic.link]p5:
// In addition, a member function, static data member, a named
// class or enumeration of class scope, or an unnamed class or
// enumeration defined in a class-scope typedef declaration such
// that the class or enumeration has the typedef name for linkage
// purposes (7.1.3), has external linkage if the name of the class
// has external linkage.
if (D->getDeclContext()->isRecord())
return getLVForClassMember(D, computation, IgnoreVarTypeLinkage);
// C++ [basic.link]p6:
// The name of a function declared in block scope and the name of
// an object declared by a block scope extern declaration have
// linkage. If there is a visible declaration of an entity with
// linkage having the same name and type, ignoring entities
// declared outside the innermost enclosing namespace scope, the
// block scope declaration declares that same entity and receives
// the linkage of the previous declaration. If there is more than
// one such matching entity, the program is ill-formed. Otherwise,
// if no matching entity is found, the block scope entity receives
// external linkage.
if (D->getDeclContext()->isFunctionOrMethod())
return getLVForLocalDecl(D, computation);
// C++ [basic.link]p6:
// Names not covered by these rules have no linkage.
return LinkageInfo::none();
}
/// getLVForDecl - Get the linkage and visibility for the given declaration.
LinkageInfo LinkageComputer::getLVForDecl(const NamedDecl *D,
LVComputationKind computation) {
// Internal_linkage attribute overrides other considerations.
if (D->hasAttr<InternalLinkageAttr>())
return getInternalLinkageFor(D);
if (computation.IgnoreAllVisibility && D->hasCachedLinkage())
return LinkageInfo(D->getCachedLinkage(), DefaultVisibility, false);
if (llvm::Optional<LinkageInfo> LI = lookup(D, computation))
return *LI;
LinkageInfo LV = computeLVForDecl(D, computation);
if (D->hasCachedLinkage())
assert(D->getCachedLinkage() == LV.getLinkage());
D->setCachedLinkage(LV.getLinkage());
cache(D, computation, LV);
#ifndef NDEBUG
// In C (because of gnu inline) and in c++ with microsoft extensions an
// static can follow an extern, so we can have two decls with different
// linkages.
const LangOptions &Opts = D->getASTContext().getLangOpts();
if (!Opts.CPlusPlus || Opts.MicrosoftExt)
return LV;
// We have just computed the linkage for this decl. By induction we know
// that all other computed linkages match, check that the one we just
// computed also does.
NamedDecl *Old = nullptr;
for (auto I : D->redecls()) {
auto *T = cast<NamedDecl>(I);
if (T == D)
continue;
if (!T->isInvalidDecl() && T->hasCachedLinkage()) {
Old = T;
break;
}
}
assert(!Old || Old->getCachedLinkage() == D->getCachedLinkage());
#endif
return LV;
}
LinkageInfo LinkageComputer::getDeclLinkageAndVisibility(const NamedDecl *D) {
return getLVForDecl(D,
LVComputationKind(usesTypeVisibility(D)
? NamedDecl::VisibilityForType
: NamedDecl::VisibilityForValue));
}
Module *Decl::getOwningModuleForLinkage(bool IgnoreLinkage) const {
Module *M = getOwningModule();
if (!M)
return nullptr;
switch (M->Kind) {
case Module::ModuleMapModule:
// Module map modules have no special linkage semantics.
return nullptr;
case Module::ModuleInterfaceUnit:
return M;
case Module::GlobalModuleFragment: {
// External linkage declarations in the global module have no owning module
// for linkage purposes. But internal linkage declarations in the global
// module fragment of a particular module are owned by that module for
// linkage purposes.
if (IgnoreLinkage)
return nullptr;
bool InternalLinkage;
if (auto *ND = dyn_cast<NamedDecl>(this))
InternalLinkage = !ND->hasExternalFormalLinkage();
else {
auto *NSD = dyn_cast<NamespaceDecl>(this);
InternalLinkage = (NSD && NSD->isAnonymousNamespace()) ||
isInAnonymousNamespace();
}
return InternalLinkage ? M->Parent : nullptr;
}
case Module::PrivateModuleFragment:
// The private module fragment is part of its containing module for linkage
// purposes.
return M->Parent;
}
llvm_unreachable("unknown module kind");
}
void NamedDecl::printName(raw_ostream &os) const {
os << Name;
}
std::string NamedDecl::getQualifiedNameAsString() const {
std::string QualName;
llvm::raw_string_ostream OS(QualName);
printQualifiedName(OS, getASTContext().getPrintingPolicy());
return OS.str();
}
void NamedDecl::printQualifiedName(raw_ostream &OS) const {
printQualifiedName(OS, getASTContext().getPrintingPolicy());
}
void NamedDecl::printQualifiedName(raw_ostream &OS,
const PrintingPolicy &P) const {
const DeclContext *Ctx = getDeclContext();
// For ObjC methods and properties, look through categories and use the
// interface as context.
if (auto *MD = dyn_cast<ObjCMethodDecl>(this))
if (auto *ID = MD->getClassInterface())
Ctx = ID;
if (auto *PD = dyn_cast<ObjCPropertyDecl>(this)) {
if (auto *MD = PD->getGetterMethodDecl())
if (auto *ID = MD->getClassInterface())
Ctx = ID;
}
if (Ctx->isFunctionOrMethod()) {
printName(OS);
return;
}
using ContextsTy = SmallVector<const DeclContext *, 8>;
ContextsTy Contexts;
// Collect named contexts.
while (Ctx) {
if (isa<NamedDecl>(Ctx))
Contexts.push_back(Ctx);
Ctx = Ctx->getParent();
}
for (const DeclContext *DC : llvm::reverse(Contexts)) {
if (const auto *Spec = dyn_cast<ClassTemplateSpecializationDecl>(DC)) {
OS << Spec->getName();
const TemplateArgumentList &TemplateArgs = Spec->getTemplateArgs();
printTemplateArgumentList(OS, TemplateArgs.asArray(), P);
} else if (const auto *ND = dyn_cast<NamespaceDecl>(DC)) {
if (P.SuppressUnwrittenScope &&
(ND->isAnonymousNamespace() || ND->isInline()))
continue;
if (ND->isAnonymousNamespace()) {
OS << (P.MSVCFormatting ? "`anonymous namespace\'"
: "(anonymous namespace)");
}
else
OS << *ND;
} else if (const auto *RD = dyn_cast<RecordDecl>(DC)) {
if (!RD->getIdentifier())
OS << "(anonymous " << RD->getKindName() << ')';
else
OS << *RD;
} else if (const auto *FD = dyn_cast<FunctionDecl>(DC)) {
const FunctionProtoType *FT = nullptr;
if (FD->hasWrittenPrototype())
FT = dyn_cast<FunctionProtoType>(FD->getType()->castAs<FunctionType>());
OS << *FD << '(';
if (FT) {
unsigned NumParams = FD->getNumParams();
for (unsigned i = 0; i < NumParams; ++i) {
if (i)
OS << ", ";
OS << FD->getParamDecl(i)->getType().stream(P);
}
if (FT->isVariadic()) {
if (NumParams > 0)
OS << ", ";
OS << "...";
}
}
OS << ')';
} else if (const auto *ED = dyn_cast<EnumDecl>(DC)) {
// C++ [dcl.enum]p10: Each enum-name and each unscoped
// enumerator is declared in the scope that immediately contains
// the enum-specifier. Each scoped enumerator is declared in the
// scope of the enumeration.
// For the case of unscoped enumerator, do not include in the qualified
// name any information about its enum enclosing scope, as its visibility
// is global.
if (ED->isScoped())
OS << *ED;
else
continue;
} else {
OS << *cast<NamedDecl>(DC);
}
OS << "::";
}
if (getDeclName() || isa<DecompositionDecl>(this))
OS << *this;
else
OS << "(anonymous)";
}
void NamedDecl::getNameForDiagnostic(raw_ostream &OS,
const PrintingPolicy &Policy,
bool Qualified) const {
if (Qualified)
printQualifiedName(OS, Policy);
else
printName(OS);
}
template<typename T> static bool isRedeclarableImpl(Redeclarable<T> *) {
return true;
}
static bool isRedeclarableImpl(...) { return false; }
static bool isRedeclarable(Decl::Kind K) {
switch (K) {
#define DECL(Type, Base) \
case Decl::Type: \
return isRedeclarableImpl((Type##Decl *)nullptr);
#define ABSTRACT_DECL(DECL)
#include "clang/AST/DeclNodes.inc"
}
llvm_unreachable("unknown decl kind");
}
bool NamedDecl::declarationReplaces(NamedDecl *OldD, bool IsKnownNewer) const {
assert(getDeclName() == OldD->getDeclName() && "Declaration name mismatch");
// Never replace one imported declaration with another; we need both results
// when re-exporting.
if (OldD->isFromASTFile() && isFromASTFile())
return false;
// A kind mismatch implies that the declaration is not replaced.
if (OldD->getKind() != getKind())
return false;
// For method declarations, we never replace. (Why?)
if (isa<ObjCMethodDecl>(this))
return false;
// For parameters, pick the newer one. This is either an error or (in
// Objective-C) permitted as an extension.
if (isa<ParmVarDecl>(this))
return true;
// Inline namespaces can give us two declarations with the same
// name and kind in the same scope but different contexts; we should
// keep both declarations in this case.
if (!this->getDeclContext()->getRedeclContext()->Equals(
OldD->getDeclContext()->getRedeclContext()))
return false;
// Using declarations can be replaced if they import the same name from the
// same context.
if (auto *UD = dyn_cast<UsingDecl>(this)) {
ASTContext &Context = getASTContext();
return Context.getCanonicalNestedNameSpecifier(UD->getQualifier()) ==
Context.getCanonicalNestedNameSpecifier(
cast<UsingDecl>(OldD)->getQualifier());
}
if (auto *UUVD = dyn_cast<UnresolvedUsingValueDecl>(this)) {
ASTContext &Context = getASTContext();
return Context.getCanonicalNestedNameSpecifier(UUVD->getQualifier()) ==
Context.getCanonicalNestedNameSpecifier(
cast<UnresolvedUsingValueDecl>(OldD)->getQualifier());
}
if (isRedeclarable(getKind())) {
if (getCanonicalDecl() != OldD->getCanonicalDecl())
return false;
if (IsKnownNewer)
return true;
// Check whether this is actually newer than OldD. We want to keep the
// newer declaration. This loop will usually only iterate once, because
// OldD is usually the previous declaration.
for (auto D : redecls()) {
if (D == OldD)
break;
// If we reach the canonical declaration, then OldD is not actually older
// than this one.
//
// FIXME: In this case, we should not add this decl to the lookup table.
if (D->isCanonicalDecl())
return false;
}
// It's a newer declaration of the same kind of declaration in the same
// scope: we want this decl instead of the existing one.
return true;
}
// In all other cases, we need to keep both declarations in case they have
// different visibility. Any attempt to use the name will result in an
// ambiguity if more than one is visible.
return false;
}
bool NamedDecl::hasLinkage() const {
return getFormalLinkage() != NoLinkage;
}
NamedDecl *NamedDecl::getUnderlyingDeclImpl() {
NamedDecl *ND = this;
while (auto *UD = dyn_cast<UsingShadowDecl>(ND))
ND = UD->getTargetDecl();
if (auto *AD = dyn_cast<ObjCCompatibleAliasDecl>(ND))
return AD->getClassInterface();
if (auto *AD = dyn_cast<NamespaceAliasDecl>(ND))
return AD->getNamespace();
return ND;
}
bool NamedDecl::isCXXInstanceMember() const {
if (!isCXXClassMember())
return false;
const NamedDecl *D = this;
if (isa<UsingShadowDecl>(D))
D = cast<UsingShadowDecl>(D)->getTargetDecl();
if (isa<FieldDecl>(D) || isa<IndirectFieldDecl>(D) || isa<MSPropertyDecl>(D))
return true;
if (const auto *MD = dyn_cast_or_null<CXXMethodDecl>(D->getAsFunction()))
return MD->isInstance();
return false;
}
//===----------------------------------------------------------------------===//
// DeclaratorDecl Implementation
//===----------------------------------------------------------------------===//
template <typename DeclT>
static SourceLocation getTemplateOrInnerLocStart(const DeclT *decl) {
if (decl->getNumTemplateParameterLists() > 0)
return decl->getTemplateParameterList(0)->getTemplateLoc();
else
return decl->getInnerLocStart();
}
SourceLocation DeclaratorDecl::getTypeSpecStartLoc() const {
TypeSourceInfo *TSI = getTypeSourceInfo();
if (TSI) return TSI->getTypeLoc().getBeginLoc();
return SourceLocation();
}
void DeclaratorDecl::setQualifierInfo(NestedNameSpecifierLoc QualifierLoc) {
if (QualifierLoc) {
// Make sure the extended decl info is allocated.
if (!hasExtInfo()) {
// Save (non-extended) type source info pointer.
auto *savedTInfo = DeclInfo.get<TypeSourceInfo*>();
// Allocate external info struct.
DeclInfo = new (getASTContext()) ExtInfo;
// Restore savedTInfo into (extended) decl info.
getExtInfo()->TInfo = savedTInfo;
}
// Set qualifier info.
getExtInfo()->QualifierLoc = QualifierLoc;
} else {
// Here Qualifier == 0, i.e., we are removing the qualifier (if any).
if (hasExtInfo()) {
if (getExtInfo()->NumTemplParamLists == 0) {
// Save type source info pointer.
TypeSourceInfo *savedTInfo = getExtInfo()->TInfo;
// Deallocate the extended decl info.
getASTContext().Deallocate(getExtInfo());
// Restore savedTInfo into (non-extended) decl info.
DeclInfo = savedTInfo;
}
else
getExtInfo()->QualifierLoc = QualifierLoc;
}
}
}
void DeclaratorDecl::setTemplateParameterListsInfo(
ASTContext &Context, ArrayRef<TemplateParameterList *> TPLists) {
assert(!TPLists.empty());
// Make sure the extended decl info is allocated.
if (!hasExtInfo()) {
// Save (non-extended) type source info pointer.
auto *savedTInfo = DeclInfo.get<TypeSourceInfo*>();
// Allocate external info struct.
DeclInfo = new (getASTContext()) ExtInfo;
// Restore savedTInfo into (extended) decl info.
getExtInfo()->TInfo = savedTInfo;
}
// Set the template parameter lists info.
getExtInfo()->setTemplateParameterListsInfo(Context, TPLists);
}
SourceLocation DeclaratorDecl::getOuterLocStart() const {
return getTemplateOrInnerLocStart(this);
}
// Helper function: returns true if QT is or contains a type
// having a postfix component.
static bool typeIsPostfix(QualType QT) {
while (true) {
const Type* T = QT.getTypePtr();
switch (T->getTypeClass()) {
default:
return false;
case Type::Pointer:
QT = cast<PointerType>(T)->getPointeeType();
break;
case Type::BlockPointer:
QT = cast<BlockPointerType>(T)->getPointeeType();
break;
case Type::MemberPointer:
QT = cast<MemberPointerType>(T)->getPointeeType();
break;
case Type::LValueReference:
case Type::RValueReference:
QT = cast<ReferenceType>(T)->getPointeeType();
break;
case Type::PackExpansion:
QT = cast<PackExpansionType>(T)->getPattern();
break;
case Type::Paren:
case Type::ConstantArray:
case Type::DependentSizedArray:
case Type::IncompleteArray:
case Type::VariableArray:
case Type::FunctionProto:
case Type::FunctionNoProto:
return true;
}
}
}
SourceRange DeclaratorDecl::getSourceRange() const {
SourceLocation RangeEnd = getLocation();
if (TypeSourceInfo *TInfo = getTypeSourceInfo()) {
// If the declaration has no name or the type extends past the name take the
// end location of the type.
if (!getDeclName() || typeIsPostfix(TInfo->getType()))
RangeEnd = TInfo->getTypeLoc().getSourceRange().getEnd();
}
return SourceRange(getOuterLocStart(), RangeEnd);
}
void QualifierInfo::setTemplateParameterListsInfo(
ASTContext &Context, ArrayRef<TemplateParameterList *> TPLists) {
// Free previous template parameters (if any).
if (NumTemplParamLists > 0) {
Context.Deallocate(TemplParamLists);
TemplParamLists = nullptr;
NumTemplParamLists = 0;
}
// Set info on matched template parameter lists (if any).
if (!TPLists.empty()) {
TemplParamLists = new (Context) TemplateParameterList *[TPLists.size()];
NumTemplParamLists = TPLists.size();
std::copy(TPLists.begin(), TPLists.end(), TemplParamLists);
}
}
//===----------------------------------------------------------------------===//
// VarDecl Implementation
//===----------------------------------------------------------------------===//
const char *VarDecl::getStorageClassSpecifierString(StorageClass SC) {
switch (SC) {
case SC_None: break;
case SC_Auto: return "auto";
case SC_Extern: return "extern";
case SC_PrivateExtern: return "__private_extern__";
case SC_Register: return "register";
case SC_Static: return "static";
}
llvm_unreachable("Invalid storage class");
}
VarDecl::VarDecl(Kind DK, ASTContext &C, DeclContext *DC,
SourceLocation StartLoc, SourceLocation IdLoc,
IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
StorageClass SC)
: DeclaratorDecl(DK, DC, IdLoc, Id, T, TInfo, StartLoc),
redeclarable_base(C) {
static_assert(sizeof(VarDeclBitfields) <= sizeof(unsigned),
"VarDeclBitfields too large!");
static_assert(sizeof(ParmVarDeclBitfields) <= sizeof(unsigned),
"ParmVarDeclBitfields too large!");
static_assert(sizeof(NonParmVarDeclBitfields) <= sizeof(unsigned),
"NonParmVarDeclBitfields too large!");
AllBits = 0;
VarDeclBits.SClass = SC;
// Everything else is implicitly initialized to false.
}
VarDecl *VarDecl::Create(ASTContext &C, DeclContext *DC,
SourceLocation StartL, SourceLocation IdL,
IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
StorageClass S) {
return new (C, DC) VarDecl(Var, C, DC, StartL, IdL, Id, T, TInfo, S);
}
VarDecl *VarDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
return new (C, ID)
VarDecl(Var, C, nullptr, SourceLocation(), SourceLocation(), nullptr,
QualType(), nullptr, SC_None);
}
void VarDecl::setStorageClass(StorageClass SC) {
assert(isLegalForVariable(SC));
VarDeclBits.SClass = SC;
}
VarDecl::TLSKind VarDecl::getTLSKind() const {
switch (VarDeclBits.TSCSpec) {
case TSCS_unspecified:
if (!hasAttr<ThreadAttr>() &&
!(getASTContext().getLangOpts().OpenMPUseTLS &&
getASTContext().getTargetInfo().isTLSSupported() &&
hasAttr<OMPThreadPrivateDeclAttr>()))
return TLS_None;
return ((getASTContext().getLangOpts().isCompatibleWithMSVC(
LangOptions::MSVC2015)) ||
hasAttr<OMPThreadPrivateDeclAttr>())
? TLS_Dynamic
: TLS_Static;
case TSCS___thread: // Fall through.
case TSCS__Thread_local:
return TLS_Static;
case TSCS_thread_local:
return TLS_Dynamic;
}
llvm_unreachable("Unknown thread storage class specifier!");
}
SourceRange VarDecl::getSourceRange() const {
if (const Expr *Init = getInit()) {
SourceLocation InitEnd = Init->getEndLoc();
// If Init is implicit, ignore its source range and fallback on
// DeclaratorDecl::getSourceRange() to handle postfix elements.
if (InitEnd.isValid() && InitEnd != getLocation())
return SourceRange(getOuterLocStart(), InitEnd);
}
return DeclaratorDecl::getSourceRange();
}
template<typename T>
static LanguageLinkage getDeclLanguageLinkage(const T &D) {
// C++ [dcl.link]p1: All function types, function names with external linkage,
// and variable names with external linkage have a language linkage.
if (!D.hasExternalFormalLinkage())
return NoLanguageLinkage;
// Language linkage is a C++ concept, but saying that everything else in C has
// C language linkage fits the implementation nicely.
ASTContext &Context = D.getASTContext();
if (!Context.getLangOpts().CPlusPlus)
return CLanguageLinkage;
// C++ [dcl.link]p4: A C language linkage is ignored in determining the
// language linkage of the names of class members and the function type of
// class member functions.
const DeclContext *DC = D.getDeclContext();
if (DC->isRecord())
return CXXLanguageLinkage;
// If the first decl is in an extern "C" context, any other redeclaration
// will have C language linkage. If the first one is not in an extern "C"
// context, we would have reported an error for any other decl being in one.
if (isFirstInExternCContext(&D))
return CLanguageLinkage;
return CXXLanguageLinkage;
}
template<typename T>
static bool isDeclExternC(const T &D) {
// Since the context is ignored for class members, they can only have C++
// language linkage or no language linkage.
const DeclContext *DC = D.getDeclContext();
if (DC->isRecord()) {
assert(D.getASTContext().getLangOpts().CPlusPlus);
return false;
}
return D.getLanguageLinkage() == CLanguageLinkage;
}
LanguageLinkage VarDecl::getLanguageLinkage() const {
return getDeclLanguageLinkage(*this);
}
bool VarDecl::isExternC() const {
return isDeclExternC(*this);
}
bool VarDecl::isInExternCContext() const {
return getLexicalDeclContext()->isExternCContext();
}
bool VarDecl::isInExternCXXContext() const {
return getLexicalDeclContext()->isExternCXXContext();
}
VarDecl *VarDecl::getCanonicalDecl() { return getFirstDecl(); }
VarDecl::DefinitionKind
VarDecl::isThisDeclarationADefinition(ASTContext &C) const {
if (isThisDeclarationADemotedDefinition())
return DeclarationOnly;
// C++ [basic.def]p2:
// A declaration is a definition unless [...] it contains the 'extern'
// specifier or a linkage-specification and neither an initializer [...],
// it declares a non-inline static data member in a class declaration [...],
// it declares a static data member outside a class definition and the variable
// was defined within the class with the constexpr specifier [...],
// C++1y [temp.expl.spec]p15:
// An explicit specialization of a static data member or an explicit
// specialization of a static data member template is a definition if the
// declaration includes an initializer; otherwise, it is a declaration.
//
// FIXME: How do you declare (but not define) a partial specialization of
// a static data member template outside the containing class?
if (isStaticDataMember()) {
if (isOutOfLine() &&
!(getCanonicalDecl()->isInline() &&
getCanonicalDecl()->isConstexpr()) &&
(hasInit() ||
// If the first declaration is out-of-line, this may be an
// instantiation of an out-of-line partial specialization of a variable
// template for which we have not yet instantiated the initializer.
(getFirstDecl()->isOutOfLine()
? getTemplateSpecializationKind() == TSK_Undeclared
: getTemplateSpecializationKind() !=
TSK_ExplicitSpecialization) ||
isa<VarTemplatePartialSpecializationDecl>(this)))
return Definition;
else if (!isOutOfLine() && isInline())
return Definition;
else
return DeclarationOnly;
}
// C99 6.7p5:
// A definition of an identifier is a declaration for that identifier that
// [...] causes storage to be reserved for that object.
// Note: that applies for all non-file-scope objects.
// C99 6.9.2p1:
// If the declaration of an identifier for an object has file scope and an
// initializer, the declaration is an external definition for the identifier
if (hasInit())
return Definition;
if (hasDefiningAttr())
return Definition;
if (const auto *SAA = getAttr<SelectAnyAttr>())
if (!SAA->isInherited())
return Definition;
// A variable template specialization (other than a static data member
// template or an explicit specialization) is a declaration until we
// instantiate its initializer.
if (auto *VTSD = dyn_cast<VarTemplateSpecializationDecl>(this)) {
if (VTSD->getTemplateSpecializationKind() != TSK_ExplicitSpecialization &&
!isa<VarTemplatePartialSpecializationDecl>(VTSD) &&
!VTSD->IsCompleteDefinition)
return DeclarationOnly;
}
if (hasExternalStorage())
return DeclarationOnly;
// [dcl.link] p7:
// A declaration directly contained in a linkage-specification is treated
// as if it contains the extern specifier for the purpose of determining
// the linkage of the declared name and whether it is a definition.
if (isSingleLineLanguageLinkage(*this))
return DeclarationOnly;
// C99 6.9.2p2:
// A declaration of an object that has file scope without an initializer,
// and without a storage class specifier or the scs 'static', constitutes
// a tentative definition.
// No such thing in C++.
if (!C.getLangOpts().CPlusPlus && isFileVarDecl())
return TentativeDefinition;
// What's left is (in C, block-scope) declarations without initializers or
// external storage. These are definitions.
return Definition;
}
VarDecl *VarDecl::getActingDefinition() {
DefinitionKind Kind = isThisDeclarationADefinition();
if (Kind != TentativeDefinition)
return nullptr;
VarDecl *LastTentative = nullptr;
VarDecl *First = getFirstDecl();
for (auto I : First->redecls()) {
Kind = I->isThisDeclarationADefinition();
if (Kind == Definition)
return nullptr;
else if (Kind == TentativeDefinition)
LastTentative = I;
}
return LastTentative;
}
VarDecl *VarDecl::getDefinition(ASTContext &C) {
VarDecl *First = getFirstDecl();
for (auto I : First->redecls()) {
if (I->isThisDeclarationADefinition(C) == Definition)
return I;
}
return nullptr;
}
VarDecl::DefinitionKind VarDecl::hasDefinition(ASTContext &C) const {
DefinitionKind Kind = DeclarationOnly;
const VarDecl *First = getFirstDecl();
for (auto I : First->redecls()) {
Kind = std::max(Kind, I->isThisDeclarationADefinition(C));
if (Kind == Definition)
break;
}
return Kind;
}
const Expr *VarDecl::getAnyInitializer(const VarDecl *&D) const {
for (auto I : redecls()) {
if (auto Expr = I->getInit()) {
D = I;
return Expr;
}
}
return nullptr;
}
bool VarDecl::hasInit() const {
if (auto *P = dyn_cast<ParmVarDecl>(this))
if (P->hasUnparsedDefaultArg() || P->hasUninstantiatedDefaultArg())
return false;
return !Init.isNull();
}
Expr *VarDecl::getInit() {
if (!hasInit())
return nullptr;
if (auto *S = Init.dyn_cast<Stmt *>())
return cast<Expr>(S);
return cast_or_null<Expr>(Init.get<EvaluatedStmt *>()->Value);
}
Stmt **VarDecl::getInitAddress() {
if (auto *ES = Init.dyn_cast<EvaluatedStmt *>())
return &ES->Value;
return Init.getAddrOfPtr1();
}
bool VarDecl::isOutOfLine() const {
if (Decl::isOutOfLine())
return true;
if (!isStaticDataMember())
return false;
// If this static data member was instantiated from a static data member of
// a class template, check whether that static data member was defined
// out-of-line.
if (VarDecl *VD = getInstantiatedFromStaticDataMember())
return VD->isOutOfLine();
return false;
}
void VarDecl::setInit(Expr *I) {
if (auto *Eval = Init.dyn_cast<EvaluatedStmt *>()) {
Eval->~EvaluatedStmt();
getASTContext().Deallocate(Eval);
}
Init = I;
}
bool VarDecl::mightBeUsableInConstantExpressions(ASTContext &C) const {
const LangOptions &Lang = C.getLangOpts();
if (!Lang.CPlusPlus)
return false;
// Function parameters are never usable in constant expressions.
if (isa<ParmVarDecl>(this))
return false;
// In C++11, any variable of reference type can be used in a constant
// expression if it is initialized by a constant expression.
if (Lang.CPlusPlus11 && getType()->isReferenceType())
return true;
// Only const objects can be used in constant expressions in C++. C++98 does
// not require the variable to be non-volatile, but we consider this to be a
// defect.
if (!getType().isConstQualified() || getType().isVolatileQualified())
return false;
// In C++, const, non-volatile variables of integral or enumeration types
// can be used in constant expressions.
if (getType()->isIntegralOrEnumerationType())
return true;
// Additionally, in C++11, non-volatile constexpr variables can be used in
// constant expressions.
return Lang.CPlusPlus11 && isConstexpr();
}
bool VarDecl::isUsableInConstantExpressions(ASTContext &Context) const {
// C++2a [expr.const]p3:
// A variable is usable in constant expressions after its initializing
// declaration is encountered...
const VarDecl *DefVD = nullptr;
const Expr *Init = getAnyInitializer(DefVD);
if (!Init || Init->isValueDependent() || getType()->isDependentType())
return false;
// ... if it is a constexpr variable, or it is of reference type or of
// const-qualified integral or enumeration type, ...
if (!DefVD->mightBeUsableInConstantExpressions(Context))
return false;
// ... and its initializer is a constant initializer.
return DefVD->checkInitIsICE();
}
/// Convert the initializer for this declaration to the elaborated EvaluatedStmt
/// form, which contains extra information on the evaluated value of the
/// initializer.
EvaluatedStmt *VarDecl::ensureEvaluatedStmt() const {
auto *Eval = Init.dyn_cast<EvaluatedStmt *>();
if (!Eval) {
// Note: EvaluatedStmt contains an APValue, which usually holds
// resources not allocated from the ASTContext. We need to do some
// work to avoid leaking those, but we do so in VarDecl::evaluateValue
// where we can detect whether there's anything to clean up or not.
Eval = new (getASTContext()) EvaluatedStmt;
Eval->Value = Init.get<Stmt *>();
Init = Eval;
}
return Eval;
}
APValue *VarDecl::evaluateValue() const {
SmallVector<PartialDiagnosticAt, 8> Notes;
return evaluateValue(Notes);
}
APValue *VarDecl::evaluateValue(
SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
EvaluatedStmt *Eval = ensureEvaluatedStmt();
// We only produce notes indicating why an initializer is non-constant the
// first time it is evaluated. FIXME: The notes won't always be emitted the
// first time we try evaluation, so might not be produced at all.
if (Eval->WasEvaluated)
return Eval->Evaluated.isAbsent() ? nullptr : &Eval->Evaluated;
const auto *Init = cast<Expr>(Eval->Value);
assert(!Init->isValueDependent());
if (Eval->IsEvaluating) {
// FIXME: Produce a diagnostic for self-initialization.
Eval->CheckedICE = true;
Eval->IsICE = false;
return nullptr;
}
Eval->IsEvaluating = true;
bool Result = Init->EvaluateAsInitializer(Eval->Evaluated, getASTContext(),
this, Notes);
// Ensure the computed APValue is cleaned up later if evaluation succeeded,
// or that it's empty (so that there's nothing to clean up) if evaluation
// failed.
if (!Result)
Eval->Evaluated = APValue();
else if (Eval->Evaluated.needsCleanup())
getASTContext().addDestruction(&Eval->Evaluated);
Eval->IsEvaluating = false;
Eval->WasEvaluated = true;
// In C++11, we have determined whether the initializer was a constant
// expression as a side-effect.
if (getASTContext().getLangOpts().CPlusPlus11 && !Eval->CheckedICE) {
Eval->CheckedICE = true;
Eval->IsICE = Result && Notes.empty();
}
return Result ? &Eval->Evaluated : nullptr;
}
APValue *VarDecl::getEvaluatedValue() const {
if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>())
if (Eval->WasEvaluated)
return &Eval->Evaluated;
return nullptr;
}
bool VarDecl::isInitKnownICE() const {
if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>())
return Eval->CheckedICE;
return false;
}
bool VarDecl::isInitICE() const {
assert(isInitKnownICE() &&
"Check whether we already know that the initializer is an ICE");
return Init.get<EvaluatedStmt *>()->IsICE;
}
bool VarDecl::checkInitIsICE() const {
// Initializers of weak variables are never ICEs.
if (isWeak())
return false;
EvaluatedStmt *Eval = ensureEvaluatedStmt();
if (Eval->CheckedICE)
// We have already checked whether this subexpression is an
// integral constant expression.
return Eval->IsICE;
const auto *Init = cast<Expr>(Eval->Value);
assert(!Init->isValueDependent());
// In C++11, evaluate the initializer to check whether it's a constant
// expression.
if (getASTContext().getLangOpts().CPlusPlus11) {
SmallVector<PartialDiagnosticAt, 8> Notes;
evaluateValue(Notes);
return Eval->IsICE;
}
// It's an ICE whether or not the definition we found is
// out-of-line. See DR 721 and the discussion in Clang PR
// 6206 for details.
if (Eval->CheckingICE)
return false;
Eval->CheckingICE = true;
Eval->IsICE = Init->isIntegerConstantExpr(getASTContext());
Eval->CheckingICE = false;
Eval->CheckedICE = true;
return Eval->IsICE;
}
bool VarDecl::isParameterPack() const {
return isa<PackExpansionType>(getType());
}
template<typename DeclT>
static DeclT *getDefinitionOrSelf(DeclT *D) {
assert(D);
if (auto *Def = D->getDefinition())
return Def;
return D;
}
bool VarDecl::isEscapingByref() const {
return hasAttr<BlocksAttr>() && NonParmVarDeclBits.EscapingByref;
}
bool VarDecl::isNonEscapingByref() const {
return hasAttr<BlocksAttr>() && !NonParmVarDeclBits.EscapingByref;
}
VarDecl *VarDecl::getTemplateInstantiationPattern() const {
const VarDecl *VD = this;
// If this is an instantiated member, walk back to the template from which
// it was instantiated.
if (MemberSpecializationInfo *MSInfo = VD->getMemberSpecializationInfo()) {
if (isTemplateInstantiation(MSInfo->getTemplateSpecializationKind())) {
VD = VD->getInstantiatedFromStaticDataMember();
while (auto *NewVD = VD->getInstantiatedFromStaticDataMember())
VD = NewVD;
}
}
// If it's an instantiated variable template specialization, find the
// template or partial specialization from which it was instantiated.
if (auto *VDTemplSpec = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
if (isTemplateInstantiation(VDTemplSpec->getTemplateSpecializationKind())) {
auto From = VDTemplSpec->getInstantiatedFrom();
if (auto *VTD = From.dyn_cast<VarTemplateDecl *>()) {
while (!VTD->isMemberSpecialization()) {
auto *NewVTD = VTD->getInstantiatedFromMemberTemplate();
if (!NewVTD)
break;
VTD = NewVTD;
}
return getDefinitionOrSelf(VTD->getTemplatedDecl());
}
if (auto *VTPSD =
From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
while (!VTPSD->isMemberSpecialization()) {
auto *NewVTPSD = VTPSD->getInstantiatedFromMember();
if (!NewVTPSD)
break;
VTPSD = NewVTPSD;
}
return getDefinitionOrSelf<VarDecl>(VTPSD);
}
}
}
// If this is the pattern of a variable template, find where it was
// instantiated from. FIXME: Is this necessary?
if (VarTemplateDecl *VarTemplate = VD->getDescribedVarTemplate()) {
while (!VarTemplate->isMemberSpecialization()) {
auto *NewVT = VarTemplate->getInstantiatedFromMemberTemplate();
if (!NewVT)
break;
VarTemplate = NewVT;
}
return getDefinitionOrSelf(VarTemplate->getTemplatedDecl());
}
if (VD == this)
return nullptr;
return getDefinitionOrSelf(const_cast<VarDecl*>(VD));
}
VarDecl *VarDecl::getInstantiatedFromStaticDataMember() const {
if (MemberSpecializationInfo *MSI = getMemberSpecializationInfo())
return cast<VarDecl>(MSI->getInstantiatedFrom());
return nullptr;
}
TemplateSpecializationKind VarDecl::getTemplateSpecializationKind() const {
if (const auto *Spec = dyn_cast<VarTemplateSpecializationDecl>(this))
return Spec->getSpecializationKind();
if (MemberSpecializationInfo *MSI = getMemberSpecializationInfo())
return MSI->getTemplateSpecializationKind();
return TSK_Undeclared;
}
TemplateSpecializationKind
VarDecl::getTemplateSpecializationKindForInstantiation() const {
if (MemberSpecializationInfo *MSI = getMemberSpecializationInfo())
return MSI->getTemplateSpecializationKind();
if (const auto *Spec = dyn_cast<VarTemplateSpecializationDecl>(this))
return Spec->getSpecializationKind();
return TSK_Undeclared;
}
SourceLocation VarDecl::getPointOfInstantiation() const {
if (const auto *Spec = dyn_cast<VarTemplateSpecializationDecl>(this))
return Spec->getPointOfInstantiation();
if (MemberSpecializationInfo *MSI = getMemberSpecializationInfo())
return MSI->getPointOfInstantiation();
return SourceLocation();
}
VarTemplateDecl *VarDecl::getDescribedVarTemplate() const {
return getASTContext().getTemplateOrSpecializationInfo(this)
.dyn_cast<VarTemplateDecl *>();
}
void VarDecl::setDescribedVarTemplate(VarTemplateDecl *Template) {
getASTContext().setTemplateOrSpecializationInfo(this, Template);
}
bool VarDecl::isKnownToBeDefined() const {
const auto &LangOpts = getASTContext().getLangOpts();
// In CUDA mode without relocatable device code, variables of form 'extern
// __shared__ Foo foo[]' are pointers to the base of the GPU core's shared
// memory pool. These are never undefined variables, even if they appear
// inside of an anon namespace or static function.
//
// With CUDA relocatable device code enabled, these variables don't get
// special handling; they're treated like regular extern variables.
if (LangOpts.CUDA && !LangOpts.GPURelocatableDeviceCode &&
hasExternalStorage() && hasAttr<CUDASharedAttr>() &&
isa<IncompleteArrayType>(getType()))
return true;
return hasDefinition();
}
bool VarDecl::isNoDestroy(const ASTContext &Ctx) const {
return hasGlobalStorage() && (hasAttr<NoDestroyAttr>() ||
(!Ctx.getLangOpts().RegisterStaticDestructors &&
!hasAttr<AlwaysDestroyAttr>()));
}
MemberSpecializationInfo *VarDecl::getMemberSpecializationInfo() const {
if (isStaticDataMember())
// FIXME: Remove ?
// return getASTContext().getInstantiatedFromStaticDataMember(this);
return getASTContext().getTemplateOrSpecializationInfo(this)
.dyn_cast<MemberSpecializationInfo *>();
return nullptr;
}
void VarDecl::setTemplateSpecializationKind(TemplateSpecializationKind TSK,
SourceLocation PointOfInstantiation) {
assert((isa<VarTemplateSpecializationDecl>(this) ||
getMemberSpecializationInfo()) &&
"not a variable or static data member template specialization");
if (VarTemplateSpecializationDecl *Spec =
dyn_cast<VarTemplateSpecializationDecl>(this)) {
Spec->setSpecializationKind(TSK);
if (TSK != TSK_ExplicitSpecialization &&
PointOfInstantiation.isValid() &&
Spec->getPointOfInstantiation().isInvalid()) {
Spec->setPointOfInstantiation(PointOfInstantiation);
if (ASTMutationListener *L = getASTContext().getASTMutationListener())
L->InstantiationRequested(this);
}
} else if (MemberSpecializationInfo *MSI = getMemberSpecializationInfo()) {
MSI->setTemplateSpecializationKind(TSK);
if (TSK != TSK_ExplicitSpecialization && PointOfInstantiation.isValid() &&
MSI->getPointOfInstantiation().isInvalid()) {
MSI->setPointOfInstantiation(PointOfInstantiation);
if (ASTMutationListener *L = getASTContext().getASTMutationListener())
L->InstantiationRequested(this);
}
}
}
void
VarDecl::setInstantiationOfStaticDataMember(VarDecl *VD,
TemplateSpecializationKind TSK) {
assert(getASTContext().getTemplateOrSpecializationInfo(this).isNull() &&
"Previous template or instantiation?");
getASTContext().setInstantiatedFromStaticDataMember(this, VD, TSK);
}
//===----------------------------------------------------------------------===//
// ParmVarDecl Implementation
//===----------------------------------------------------------------------===//
ParmVarDecl *ParmVarDecl::Create(ASTContext &C, DeclContext *DC,
SourceLocation StartLoc,
SourceLocation IdLoc, IdentifierInfo *Id,
QualType T, TypeSourceInfo *TInfo,
StorageClass S, Expr *DefArg) {
return new (C, DC) ParmVarDecl(ParmVar, C, DC, StartLoc, IdLoc, Id, T, TInfo,
S, DefArg);