//===- llvm/ADT/ilist_node_base.h - Intrusive List Node Base -----*- C++ -*-==//
 
//
 
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 
// See https://llvm.org/LICENSE.txt for license information.
 
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
//
 
//===----------------------------------------------------------------------===//
 
 
 
#ifndef LLVM_ADT_ILIST_NODE_BASE_H
 
#define LLVM_ADT_ILIST_NODE_BASE_H
 
 
 
#include "llvm/ADT/PointerIntPair.h"
 
 
 
namespace llvm {
 
 
 
/// Base class for ilist nodes.
 
///
 
/// Optionally tracks whether this node is the sentinel.
 
template <bool EnableSentinelTracking> class ilist_node_base;
 
 
 
template <> class ilist_node_base<false> {
 
  ilist_node_base *Prev = nullptr;
 
  ilist_node_base *Next = nullptr;
 
 
 
public:
 
  void setPrev(ilist_node_base *Prev) { this->Prev = Prev; }
 
  void setNext(ilist_node_base *Next) { this->Next = Next; }
 
  ilist_node_base *getPrev() const { return Prev; }
 
  ilist_node_base *getNext() const { return Next; }
 
 
 
  bool isKnownSentinel() const { return false; }
 
  void initializeSentinel() {}
 
};
 
 
 
template <> class ilist_node_base<true> {
 
  PointerIntPair<ilist_node_base *, 1> PrevAndSentinel;
 
  ilist_node_base *Next = nullptr;
 
 
 
public:
 
  void setPrev(ilist_node_base *Prev) { PrevAndSentinel.setPointer(Prev); }
 
  void setNext(ilist_node_base *Next) { this->Next = Next; }
 
  ilist_node_base *getPrev() const { return PrevAndSentinel.getPointer(); }
 
  ilist_node_base *getNext() const { return Next; }
 
 
 
  bool isSentinel() const { return PrevAndSentinel.getInt(); }
 
  bool isKnownSentinel() const { return isSentinel(); }
 
  void initializeSentinel() { PrevAndSentinel.setInt(true); }
 
};
 
 
 
} // end namespace llvm
 
 
 
#endif // LLVM_ADT_ILIST_NODE_BASE_H