1 //===-- tsan_ilist.h --------------------------------------------*- 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 // This file is a part of ThreadSanitizer (TSan), a race detector.
10 //
11 //===----------------------------------------------------------------------===//
12 #ifndef TSAN_ILIST_H
13 #define TSAN_ILIST_H
14
15 #include "sanitizer_common/sanitizer_internal_defs.h"
16
17 namespace __tsan {
18
19 class INode {
20 public:
21 INode() = default;
22
23 private:
24 INode* next_ = nullptr;
25 INode* prev_ = nullptr;
26
27 template <typename Base, INode Base::*Node, typename Elem>
28 friend class IList;
29 INode(const INode&) = delete;
30 void operator=(const INode&) = delete;
31 };
32
33 // Intrusive doubly-linked list.
34 //
35 // The node class (MyNode) needs to include "INode foo" field,
36 // then the list can be declared as IList<MyNode, &MyNode::foo>.
37 // This design allows to link MyNode into multiple lists using
38 // different INode fields.
39 // The optional Elem template argument allows to specify node MDT
40 // (most derived type) if it's different from MyNode.
41 template <typename Base, INode Base::*Node, typename Elem = Base>
42 class IList {
43 public:
44 IList();
45
46 void PushFront(Elem* e);
47 void PushBack(Elem* e);
48 void Remove(Elem* e);
49
50 Elem* PopFront();
51 Elem* PopBack();
52 Elem* Front();
53 Elem* Back();
54
55 // Prev links point towards front of the queue.
56 Elem* Prev(Elem* e);
57 // Next links point towards back of the queue.
58 Elem* Next(Elem* e);
59
60 uptr Size() const;
61 bool Empty() const;
62 bool Queued(Elem* e) const;
63
64 private:
65 INode node_;
66 uptr size_ = 0;
67
68 void Push(Elem* e, INode* after);
69 static INode* ToNode(Elem* e);
70 static Elem* ToElem(INode* n);
71
72 IList(const IList&) = delete;
73 void operator=(const IList&) = delete;
74 };
75
76 template <typename Base, INode Base::*Node, typename Elem>
77 IList<Base, Node, Elem>::IList() {
78 node_.next_ = node_.prev_ = &node_;
79 }
80
81 template <typename Base, INode Base::*Node, typename Elem>
82 void IList<Base, Node, Elem>::PushFront(Elem* e) {
83 Push(e, &node_);
84 }
85
86 template <typename Base, INode Base::*Node, typename Elem>
87 void IList<Base, Node, Elem>::PushBack(Elem* e) {
88 Push(e, node_.prev_);
89 }
90
91 template <typename Base, INode Base::*Node, typename Elem>
92 void IList<Base, Node, Elem>::Push(Elem* e, INode* after) {
93 INode* n = ToNode(e);
94 DCHECK_EQ(n->next_, nullptr);
95 DCHECK_EQ(n->prev_, nullptr);
96 INode* next = after->next_;
97 n->next_ = next;
98 n->prev_ = after;
99 next->prev_ = n;
100 after->next_ = n;
101 size_++;
102 }
103
104 template <typename Base, INode Base::*Node, typename Elem>
105 void IList<Base, Node, Elem>::Remove(Elem* e) {
106 INode* n = ToNode(e);
107 INode* next = n->next_;
108 INode* prev = n->prev_;
109 DCHECK(next);
110 DCHECK(prev);
111 DCHECK(size_);
112 next->prev_ = prev;
113 prev->next_ = next;
114 n->prev_ = n->next_ = nullptr;
115 size_--;
116 }
117
118 template <typename Base, INode Base::*Node, typename Elem>
119 Elem* IList<Base, Node, Elem>::PopFront() {
120 Elem* e = Front();
121 if (e)
122 Remove(e);
123 return e;
124 }
125
126 template <typename Base, INode Base::*Node, typename Elem>
127 Elem* IList<Base, Node, Elem>::PopBack() {
128 Elem* e = Back();
129 if (e)
130 Remove(e);
131 return e;
132 }
133
134 template <typename Base, INode Base::*Node, typename Elem>
135 Elem* IList<Base, Node, Elem>::Front() {
136 return size_ ? ToElem(node_.next_) : nullptr;
137 }
138
139 template <typename Base, INode Base::*Node, typename Elem>
140 Elem* IList<Base, Node, Elem>::Back() {
141 return size_ ? ToElem(node_.prev_) : nullptr;
142 }
143
144 template <typename Base, INode Base::*Node, typename Elem>
145 Elem* IList<Base, Node, Elem>::Prev(Elem* e) {
146 INode* n = ToNode(e);
147 DCHECK(n->prev_);
148 return n->prev_ != &node_ ? ToElem(n->prev_) : nullptr;
149 }
150
151 template <typename Base, INode Base::*Node, typename Elem>
152 Elem* IList<Base, Node, Elem>::Next(Elem* e) {
153 INode* n = ToNode(e);
154 DCHECK(n->next_);
155 return n->next_ != &node_ ? ToElem(n->next_) : nullptr;
156 }
157
158 template <typename Base, INode Base::*Node, typename Elem>
159 uptr IList<Base, Node, Elem>::Size() const {
160 return size_;
161 }
162
163 template <typename Base, INode Base::*Node, typename Elem>
164 bool IList<Base, Node, Elem>::Empty() const {
165 return size_ == 0;
166 }
167
168 template <typename Base, INode Base::*Node, typename Elem>
169 bool IList<Base, Node, Elem>::Queued(Elem* e) const {
170 INode* n = ToNode(e);
171 DCHECK_EQ(!n->next_, !n->prev_);
172 return n->next_;
173 }
174
175 template <typename Base, INode Base::*Node, typename Elem>
176 INode* IList<Base, Node, Elem>::ToNode(Elem* e) {
177 return &(e->*Node);
178 }
179
180 template <typename Base, INode Base::*Node, typename Elem>
181 Elem* IList<Base, Node, Elem>::ToElem(INode* n) {
182 return static_cast<Elem*>(reinterpret_cast<Base*>(
183 reinterpret_cast<uptr>(n) -
184 reinterpret_cast<uptr>(&(reinterpret_cast<Elem*>(0)->*Node))));
185 }
186
187 } // namespace __tsan
188
189 #endif