blob: b279ef86e55fdd3e53200a49d8ce76d9fa257874 [file] [log] [blame]
//===--- Consumption.h - Value consumption for SIL --------------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the CastConsumptionKind enum, which describes
// under what circumstances an operation consumes a value.
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_SIL_CONSUMPTION_H
#define SWIFT_SIL_CONSUMPTION_H
namespace swift {
/// Is an operation a "take"? A take consumes the original value,
/// leaving it uninitialized.
enum IsTake_t : bool { IsNotTake, IsTake };
/// Is an operation an "initialization"? An initialization simply
/// fills in an uninitialized address with a value; a
/// non-initialization also consumes the value already there.
enum IsInitialization_t : bool { IsNotInitialization, IsInitialization };
/// The behavior of a dynamic cast operation on the source value.
enum class CastConsumptionKind : uint8_t {
/// The source value is always taken, regardless of whether the cast
/// succeeds. That is, if the cast fails, the source value is
/// destroyed.
TakeAlways,
/// The source value is taken only on a successful cast; otherwise,
/// it is left in place.
TakeOnSuccess,
/// The source value is always left in place, and the destination
/// value is copied into on success.
CopyOnSuccess,
};
/// Should the source value be destroyed if the cast fails?
inline bool shouldDestroyOnFailure(CastConsumptionKind kind) {
return (kind == CastConsumptionKind::TakeAlways);
}
/// Should the source value be taken if the cast succeeds?
inline IsTake_t shouldTakeOnSuccess(CastConsumptionKind kind) {
return IsTake_t(kind != CastConsumptionKind::CopyOnSuccess);
}
} // end namespace swift
#endif