lib/IRGen/Temporary.h

//===--- Temporary.h - A temporary allocation -------------------*- 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 Temporary and TemporarySet classes.
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_IRGEN_TEMPORARY_H
#define SWIFT_IRGEN_TEMPORARY_H

#include "Address.h"
#include "swift/SIL/SILType.h"
#include <vector>

namespace swift {
namespace irgen {

class IRGenFunction;

/// A temporary allocation.
class Temporary {
public:
  StackAddress Addr;
  SILType Type;

  void destroy(IRGenFunction &IGF) const;
};

class TemporarySet {
  std::vector<Temporary> Stack;
  bool HasBeenCleared = false;

public:
  TemporarySet() = default;

  TemporarySet(TemporarySet &&) = default;
  TemporarySet &operator=(TemporarySet &&) = default;

  // Make this move-only to reduce chances of double-destroys.  We can't
  // get too strict with this, though, because we may need to destroy
  // the same set of temporaries along multiple control-flow paths.
  TemporarySet(const TemporarySet &) = delete;
  TemporarySet &operator=(const TemporarySet &) = delete;

  void add(Temporary temp) {
    Stack.push_back(temp);
  }

  /// Destroy all the temporaries.
  void destroyAll(IRGenFunction &IGF) const;

  /// Remove all the temporaries from this set.  This does not destroy
  /// the temporaries.
  void clear() {
    assert(!HasBeenCleared && "already cleared");
    HasBeenCleared = true;
    Stack.clear();
  }

  /// Has clear() been called on this set?
  bool hasBeenCleared() const {
    return HasBeenCleared;
  }
};

} // end namespace irgen
} // end namespace swift

#endif