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More groundwork for protocols with superclass constraints. In several places we need to distinguish between existential types that have a superclass term (MyClass & Proto) and existential types containing a protocol with a superclass constraint. This is similar to how I can write 'AnyObject & Proto', or write 'Proto1 & Proto2' where Proto1 has an ': AnyObject' in its inheritance clause. Note that some of the usages will be revisited later as I do more refactoring and testing. This is just a first pass.
102 lines
3.1 KiB
C++
102 lines
3.1 KiB
C++
//===--- ExistentialLayout.h - Existential type decomposition ---*- C++ -*-===//
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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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//
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// This file defines the ExistentialLayout struct.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_EXISTENTIAL_LAYOUT_H
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#define SWIFT_EXISTENTIAL_LAYOUT_H
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#include "swift/Basic/ArrayRefView.h"
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/Type.h"
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#include "llvm/ADT/SmallVector.h"
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namespace swift {
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class ProtocolDecl;
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class ProtocolType;
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class ProtocolCompositionType;
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struct ExistentialLayout {
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ExistentialLayout() {
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hasExplicitAnyObject = false;
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containsNonObjCProtocol = false;
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singleProtocol = nullptr;
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}
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ExistentialLayout(ProtocolType *type);
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ExistentialLayout(ProtocolCompositionType *type);
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/// The explicit superclass constraint, if any.
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Type explicitSuperclass;
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/// Whether the existential contains an explicit '& AnyObject' constraint.
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bool hasExplicitAnyObject : 1;
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/// Whether any protocol members are non-@objc.
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bool containsNonObjCProtocol : 1;
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bool isAnyObject() const;
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bool isObjC() const {
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// FIXME: Does the superclass have to be @objc?
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return ((explicitSuperclass ||
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hasExplicitAnyObject ||
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!getProtocols().empty()) &&
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!containsNonObjCProtocol);
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}
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/// Whether the existential requires a class, either via an explicit
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/// '& AnyObject' member or because of a superclass or protocol constraint.
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bool requiresClass() const;
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/// Returns the existential's superclass, if any; this is either an explicit
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/// superclass term in a composition type, or the superclass of one of the
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/// protocols.
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Type getSuperclass() const;
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/// Does this existential contain the Error protocol?
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bool isExistentialWithError(ASTContext &ctx) const;
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/// Does this existential consist of an Error protocol only with no other
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/// constraints?
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bool isErrorExistential() const;
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static inline ProtocolType *getProtocolType(const Type &Ty) {
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return cast<ProtocolType>(Ty.getPointer());
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}
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typedef ArrayRefView<Type,ProtocolType*,getProtocolType> ProtocolTypeArrayRef;
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ProtocolTypeArrayRef getProtocols() const & {
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if (singleProtocol)
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return llvm::makeArrayRef(&singleProtocol, 1);
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return protocols;
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}
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/// The returned ArrayRef may point directly to \c this->singleProtocol, so
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/// calling this on a temporary is likely to be incorrect.
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ProtocolTypeArrayRef getProtocols() const && = delete;
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LayoutConstraint getLayoutConstraint() const;
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private:
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// The protocol from a ProtocolType
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Type singleProtocol;
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/// Zero or more protocol constraints from a ProtocolCompositionType
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ArrayRef<Type> protocols;
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};
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}
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#endif // SWIFT_EXISTENTIAL_LAYOUT_H
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