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8bebb084e6
It's witnessing protocol requirements, not values, and "value witness" has a particular meaning in IRGen. Swift SVN r11814
70 lines
2.2 KiB
C++
70 lines
2.2 KiB
C++
//===--- Requirement.h - Swift Requirement ASTs -----------------*- 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 - 2015 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 http://swift.org/LICENSE.txt for license information
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// See http://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 Requirement class and subclasses.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_AST_REQUIREMENT_H
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#define SWIFT_AST_REQUIREMENT_H
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#include "swift/AST/Type.h"
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#include "llvm/ADT/PointerIntPair.h"
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namespace swift {
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/// \brief Describes the kind of a requirement that occurs within a requirements
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/// clause.
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enum class RequirementKind : unsigned int {
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/// A conformance requirement T : P, where T is a type that depends
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/// on a generic parameter and P is a protocol to which T must conform.
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Conformance,
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/// A same-type requirement T == U, where T and U are types that shall be
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/// equivalent.
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SameType,
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/// A marker that indicates where the witness for the given (first)
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/// type should be located.
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///
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/// FIXME: This is a crutch used to help us eliminate various walks over
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/// "all archetypes".
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WitnessMarker
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};
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/// \brief A single requirement placed on the type parameters (or associated
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/// types thereof) of a
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class Requirement {
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llvm::PointerIntPair<Type, 2, RequirementKind> FirstTypeAndKind;
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Type SecondType;
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public:
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/// Create a conformance or same-type requirement.
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Requirement(RequirementKind kind, Type first, Type second)
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: FirstTypeAndKind(first, kind), SecondType(second) { }
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/// \brief Determine the kind of requirement.
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RequirementKind getKind() const { return FirstTypeAndKind.getInt(); }
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/// \brief Retrieve the first type.
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Type getFirstType() const {
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return FirstTypeAndKind.getPointer();
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}
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/// \brief Retrieve the second type.
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Type getSecondType() const {
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return SecondType;
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}
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};
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} // end namespace swift
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#endif
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