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//===--- ForeignRepresentationInfo.h - Used in bridging queries -*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_FOREIGNREPRESENTATIONINFO_H
#define SWIFT_FOREIGNREPRESENTATIONINFO_H
#include "swift/AST/Type.h"
#include "swift/Basic/LLVM.h"
#include "llvm/ADT/PointerEmbeddedInt.h"
#include "llvm/ADT/PointerIntPair.h"
namespace swift {
class ProtocolConformance;
class ForeignRepresentationInfo {
using PayloadTy =
llvm::PointerEmbeddedInt<uintptr_t, sizeof(uintptr_t) * CHAR_BIT - 3>;
/// The low three bits store a ForeignRepresentableKind.
///
/// When the ForeignRepresentableKind == None, the upper bits are
/// the generation count at which this negative result was last checked.
/// When it's Bridged, it's the conformance that describes the bridging.
/// When it's Trivial, it's simply a flag stating whether Optional is
/// supported.
llvm::PointerIntPair<PayloadTy, 3, ForeignRepresentableKind> Storage;
public:
/// Retrieve a cache entry for a non-foreign-representable type.
static ForeignRepresentationInfo forNone(unsigned generation = 0) {
ForeignRepresentationInfo result;
result.Storage = { generation, ForeignRepresentableKind::None };
return result;
}
// Retrieve a cache entry for a trivially representable type.
static ForeignRepresentationInfo forTrivial() {
ForeignRepresentationInfo result;
result.Storage = { 0, ForeignRepresentableKind::Trivial };
return result;
}
// Retrieve a cache entry for a trivially representable type that can also
// be optional.
static ForeignRepresentationInfo forTrivialWithOptional() {
ForeignRepresentationInfo result;
result.Storage = { 1, ForeignRepresentableKind::Trivial };
return result;
}
// Retrieve a cache entry for a bridged representable type.
static ForeignRepresentationInfo
forBridged(ProtocolConformance *conformance) {
using PayloadTraits = llvm::PointerLikeTypeTraits<PayloadTy>;
ForeignRepresentationInfo result;
result.Storage = {PayloadTraits::getFromVoidPointer(conformance),
ForeignRepresentableKind::Bridged};
assert(result.getConformance() == conformance && "insufficiently aligned");
return result;
}
// Retrieve a cache entry for a trivially representable type that can also
// be optional.
static ForeignRepresentationInfo forBridgedError() {
ForeignRepresentationInfo result;
result.Storage = { 0, ForeignRepresentableKind::BridgedError };
return result;
}
/// Retrieve the foreign representable kind.
ForeignRepresentableKind getKind() const {
return Storage.getInt();
}
/// Retrieve the generation for a non-representable type.
unsigned getGeneration() const {
assert(getKind() == ForeignRepresentableKind::None);
return Storage.getPointer();
}
/// Retrieve the protocol conformance that makes it representable.
ProtocolConformance *getConformance() const {
switch (getKind()) {
case ForeignRepresentableKind::None:
llvm_unreachable("this type is not representable");
case ForeignRepresentableKind::Trivial:
case ForeignRepresentableKind::BridgedError:
return nullptr;
case ForeignRepresentableKind::Bridged: {
using PayloadTraits = llvm::PointerLikeTypeTraits<PayloadTy>;
auto payload = PayloadTraits::getAsVoidPointer(Storage.getPointer());
return static_cast<ProtocolConformance *>(payload);
}
case ForeignRepresentableKind::Object:
case ForeignRepresentableKind::StaticBridged:
llvm_unreachable("unexpected kind in ForeignRepresentableCacheEntry");
}
llvm_unreachable("Unhandled ForeignRepresentableKind in switch.");
}
/// Returns true if the optional version of this type is also representable.
bool isRepresentableAsOptional() const;
};
} // end namespace swift
#endif // SWIFT_FOREIGNREPRESENTATIONINFO_H
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