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294 lines
10 KiB
C++
294 lines
10 KiB
C++
//===--- SIL.cpp - Implements random SIL functionality --------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#include "swift/SIL/FormalLinkage.h"
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#include "swift/SIL/SILModule.h"
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#include "swift/SIL/SILBuilder.h"
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#include "swift/SIL/SILDeclRef.h"
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#include "swift/SIL/SILType.h"
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#include "swift/SIL/SILUndef.h"
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/AnyFunctionRef.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/GenericEnvironment.h"
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#include "swift/AST/Pattern.h"
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#include "swift/AST/ParameterList.h"
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#include "swift/AST/ProtocolConformance.h"
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#include "swift/ClangImporter/ClangModule.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/Decl.h"
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#include "clang/AST/DeclObjC.h"
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using namespace swift;
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FormalLinkage swift::getDeclLinkage(const ValueDecl *D) {
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const DeclContext *fileContext = D->getDeclContext()->getModuleScopeContext();
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// Clang declarations are public and can't be assured of having a
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// unique defining location.
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if (isa<ClangModuleUnit>(fileContext))
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return FormalLinkage::PublicNonUnique;
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switch (D->getEffectiveAccess()) {
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case AccessLevel::Public:
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case AccessLevel::Open:
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return FormalLinkage::PublicUnique;
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case AccessLevel::Internal:
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return FormalLinkage::HiddenUnique;
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case AccessLevel::FilePrivate:
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case AccessLevel::Private:
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return FormalLinkage::Private;
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}
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llvm_unreachable("Unhandled access level in switch.");
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}
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SILLinkage swift::getSILLinkage(FormalLinkage linkage,
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ForDefinition_t forDefinition) {
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switch (linkage) {
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case FormalLinkage::PublicUnique:
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return (forDefinition ? SILLinkage::Public : SILLinkage::PublicExternal);
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case FormalLinkage::PublicNonUnique:
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// FIXME: any place we have to do this that actually requires
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// uniqueness is buggy.
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return (forDefinition ? SILLinkage::Shared : SILLinkage::PublicExternal);
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case FormalLinkage::HiddenUnique:
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return (forDefinition ? SILLinkage::Hidden : SILLinkage::HiddenExternal);
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case FormalLinkage::Private:
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return SILLinkage::Private;
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}
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llvm_unreachable("bad formal linkage");
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}
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SILLinkage
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swift::getLinkageForProtocolConformance(const RootProtocolConformance *C,
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ForDefinition_t definition) {
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// If the conformance was synthesized by the ClangImporter, give it
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// shared linkage.
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if (isa<ClangModuleUnit>(C->getDeclContext()->getModuleScopeContext()))
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return SILLinkage::Shared;
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auto typeDecl = C->getType()->getNominalOrBoundGenericNominal();
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AccessLevel access = std::min(C->getProtocol()->getEffectiveAccess(),
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typeDecl->getEffectiveAccess());
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switch (access) {
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case AccessLevel::Private:
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case AccessLevel::FilePrivate:
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return (definition ? SILLinkage::Private : SILLinkage::PrivateExternal);
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case AccessLevel::Internal:
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return (definition ? SILLinkage::Hidden : SILLinkage::HiddenExternal);
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default:
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return (definition ? SILLinkage::Public : SILLinkage::PublicExternal);
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}
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}
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bool SILModule::isTypeMetadataAccessible(CanType type) {
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// SILModules built for the debugger have special powers to access metadata
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// for types in other files/modules.
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if (getASTContext().LangOpts.DebuggerSupport)
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return true;
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assert(type->isLegalFormalType());
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return !type.findIf([&](CanType type) {
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// Note that this function returns true if the type is *illegal* to use.
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// Ignore non-nominal types.
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auto decl = type.getNominalOrBoundGenericNominal();
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if (!decl)
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return false;
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// Check whether the declaration is inaccessible from the current context.
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switch (getDeclLinkage(decl)) {
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// Public declarations are accessible from everywhere.
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case FormalLinkage::PublicUnique:
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case FormalLinkage::PublicNonUnique:
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return false;
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// Hidden declarations are inaccessible from different modules.
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case FormalLinkage::HiddenUnique:
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return (decl->getModuleContext() != getSwiftModule());
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// Private declarations are inaccessible from different files unless
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// this is WMO and we're in the same module.
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case FormalLinkage::Private: {
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// The only time we don't have an associated DC is in the
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// integrated REPL, where we also don't have a concept of other
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// source files within the current module.
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if (!AssociatedDeclContext)
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return (decl->getModuleContext() != getSwiftModule());
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// The associated DC should be either a SourceFile or, in WMO mode,
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// a ModuleDecl. In the WMO modes, IRGen will ensure that private
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// declarations are usable throughout the module. Therefore, in
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// either case we just need to make sure that the declaration comes
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// from within the associated DC.
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auto declDC = decl->getDeclContext();
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return !(declDC == AssociatedDeclContext ||
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declDC->isChildContextOf(AssociatedDeclContext));
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}
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}
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llvm_unreachable("bad linkage");
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});
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}
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/// Answer whether IRGen's emitTypeMetadataForLayout can fetch metadata for
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/// a type, which is the necessary condition for being able to do value
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/// operations on the type using dynamic metadata.
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static bool isTypeMetadataForLayoutAccessible(SILModule &M, SILType type) {
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// Look through types that aren't necessarily legal formal types:
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// - tuples
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if (auto tupleType = type.getAs<TupleType>()) {
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for (auto index : indices(tupleType.getElementTypes())) {
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if (!isTypeMetadataForLayoutAccessible(M, type.getTupleElementType(index)))
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return false;
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}
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return true;
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}
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// - optionals
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if (auto objType = type.getOptionalObjectType()) {
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return isTypeMetadataForLayoutAccessible(M, objType);
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}
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// - function types
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if (type.is<SILFunctionType>())
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return true;
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// - metatypes
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if (type.is<AnyMetatypeType>())
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return true;
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// Otherwise, check that we can fetch the type metadata.
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return M.isTypeMetadataAccessible(type.getASTType());
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}
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/// Can we perform value operations on the given type? We have no way
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/// of doing value operations on resilient-layout types from other modules
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/// that are ABI-private to their defining module. But if the type is not
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/// ABI-private, we can always at least fetch its metadata and use the
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/// value witness table stored there.
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bool SILModule::isTypeABIAccessible(SILType type,
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TypeExpansionContext forExpansion) {
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// Fixed-ABI types can have value operations done without metadata.
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if (Types.getTypeLowering(type, forExpansion).isFixedABI())
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return true;
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assert(!type.is<ReferenceStorageType>() &&
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!type.is<SILFunctionType>() &&
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!type.is<AnyMetatypeType>() &&
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"unexpected SIL lowered-only type with non-fixed layout");
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// Otherwise, we need to be able to fetch layout-metadata for the type.
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return isTypeMetadataForLayoutAccessible(type);
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}
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bool SILModule::isTypeMetadataForLayoutAccessible(SILType type) {
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if (type.is<ReferenceStorageType>() || type.is<SILFunctionType>() ||
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type.is<AnyMetatypeType>())
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return false;
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return ::isTypeMetadataForLayoutAccessible(*this, type);
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}
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bool AbstractStorageDecl::exportsPropertyDescriptor() const {
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// The storage needs a descriptor if it sits at a module's ABI boundary,
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// meaning it has public linkage.
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// TODO: Global and static properties ought to eventually be referenceable
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// as key paths from () or T.Type too.
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if (!getDeclContext()->isTypeContext() || isStatic())
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return false;
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// Protocol requirements do not need property descriptors.
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if (isa<ProtocolDecl>(getDeclContext()))
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return false;
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// FIXME: We should support properties and subscripts with '_read' accessors;
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// 'get' is not part of the opaque accessor set there.
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auto *getter = getOpaqueAccessor(AccessorKind::Get);
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if (!getter)
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return false;
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// If the getter is mutating, we cannot form a keypath to it at all.
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if (isGetterMutating())
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return false;
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// If the storage is an ABI-compatible override of another declaration, we're
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// not going to be emitting a property descriptor either.
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if (!isValidKeyPathComponent())
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return false;
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// TODO: If previous versions of an ABI-stable binary needed the descriptor,
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// then we still do.
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// Check the linkage of the declaration.
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auto getterLinkage = SILDeclRef(getter).getLinkage(ForDefinition);
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switch (getterLinkage) {
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case SILLinkage::Public:
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case SILLinkage::PublicNonABI:
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// We may need a descriptor.
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break;
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case SILLinkage::Shared:
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case SILLinkage::Private:
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case SILLinkage::Hidden:
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// Don't need a public descriptor.
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return false;
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case SILLinkage::HiddenExternal:
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case SILLinkage::PrivateExternal:
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case SILLinkage::PublicExternal:
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case SILLinkage::SharedExternal:
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llvm_unreachable("should be definition linkage?");
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}
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// Subscripts with inout arguments (FIXME)and reabstracted arguments(/FIXME)
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// don't have descriptors either.
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if (auto sub = dyn_cast<SubscriptDecl>(this)) {
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for (auto *index : *sub->getIndices()) {
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// Keypaths can't capture inout indices.
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if (index->isInOut())
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return false;
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auto indexTy = index->getInterfaceType()
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->getCanonicalType(sub->getGenericSignatureOfContext());
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// TODO: Handle reabstraction and tuple explosion in thunk generation.
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// This wasn't previously a concern because anything that was Hashable
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// had only one abstraction level and no explosion.
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if (isa<TupleType>(indexTy))
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return false;
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auto indexObjTy = indexTy;
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if (auto objTy = indexObjTy.getOptionalObjectType())
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indexObjTy = objTy;
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if (isa<AnyFunctionType>(indexObjTy)
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|| isa<AnyMetatypeType>(indexObjTy))
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return false;
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}
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}
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return true;
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}
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