1//===- llvm/ADT/ilist_node_base.h - Intrusive List Node Base -----*- C++ -*-==//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_ADT_ILIST_NODE_BASE_H
10#define LLVM_ADT_ILIST_NODE_BASE_H
11
12#include "llvm/ADT/PointerIntPair.h"
13
14namespace llvm {
15
16/// Base class for ilist nodes.
17///
18/// Optionally tracks whether this node is the sentinel.
19template <bool EnableSentinelTracking> class ilist_node_base;
20
21template <> class ilist_node_base<false> {
22 ilist_node_base *Prev = nullptr;
23 ilist_node_base *Next = nullptr;
24
25public:
26 void setPrev(ilist_node_base *Prev) { this->Prev = Prev; }
27 void setNext(ilist_node_base *Next) { this->Next = Next; }
28 ilist_node_base *getPrev() const { return Prev; }
29 ilist_node_base *getNext() const { return Next; }
30
31 bool isKnownSentinel() const { return false; }
32 void initializeSentinel() {}
33};
34
35template <> class ilist_node_base<true> {
36 PointerIntPair<ilist_node_base *, 1> PrevAndSentinel;
37 ilist_node_base *Next = nullptr;
38
39public:
40 void setPrev(ilist_node_base *Prev) { PrevAndSentinel.setPointer(Prev); }
41 void setNext(ilist_node_base *Next) { this->Next = Next; }
42 ilist_node_base *getPrev() const { return PrevAndSentinel.getPointer(); }
43 ilist_node_base *getNext() const { return Next; }
44
45 bool isSentinel() const { return PrevAndSentinel.getInt(); }
46 bool isKnownSentinel() const { return isSentinel(); }
47 void initializeSentinel() { PrevAndSentinel.setInt(true); }
48};
49
50} // end namespace llvm
51
52#endif // LLVM_ADT_ILIST_NODE_BASE_H
53