mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
6bb92533f6
Since it is an always take, we know that the original value will always be invalidated by the checked_cast_addr_br. This also lets me use this to recognize simple cases of checked casts in opt-remark-gen.
91 lines
3.1 KiB
C++
91 lines
3.1 KiB
C++
//===--- 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
|
|
|
|
#include "llvm/Support/ErrorHandling.h"
|
|
#include <cstdint>
|
|
|
|
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,
|
|
|
|
/// The source value is never taken, regardless of whether the cast
|
|
/// succeeds. Instead, we always borrow the source value and feed it through.
|
|
///
|
|
/// NOTE: This can only be used with objects. We do not support borrowing of
|
|
/// addresses. If an address is needed for a cast operation, a BorrowAlways
|
|
/// value must be copied into a temporary and operated upon. If the result of
|
|
/// the cast is a loadable type then the value is loaded using a
|
|
/// load_borrow. If an address only value is returned, we continue processing
|
|
/// the value as an owned TakeAlways value.
|
|
BorrowAlways,
|
|
};
|
|
|
|
/// Should the source value be destroyed if the cast fails?
|
|
inline bool shouldDestroyOnFailure(CastConsumptionKind kind) {
|
|
switch (kind) {
|
|
case CastConsumptionKind::TakeAlways:
|
|
return true;
|
|
case CastConsumptionKind::TakeOnSuccess:
|
|
case CastConsumptionKind::CopyOnSuccess:
|
|
case CastConsumptionKind::BorrowAlways:
|
|
return false;
|
|
}
|
|
llvm_unreachable("covered switch");
|
|
}
|
|
|
|
/// Should the source value be taken if the cast succeeds?
|
|
inline IsTake_t shouldTakeOnSuccess(CastConsumptionKind kind) {
|
|
switch (kind) {
|
|
case CastConsumptionKind::TakeAlways:
|
|
case CastConsumptionKind::TakeOnSuccess:
|
|
return IsTake;
|
|
case CastConsumptionKind::CopyOnSuccess:
|
|
case CastConsumptionKind::BorrowAlways:
|
|
return IsNotTake;
|
|
}
|
|
llvm_unreachable("covered switch");
|
|
}
|
|
|
|
} // end namespace swift
|
|
|
|
#endif
|