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1 : //===- llvm/ADT/ilist_node.h - Intrusive Linked List Helper -----*- 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 : /// \file
10 : /// This file defines the ilist_node class template, which is a convenient
11 : /// base class for creating classes that can be used with ilists.
12 : ///
13 : //===----------------------------------------------------------------------===//
14 :
15 : #ifndef LLVM_ADT_ILIST_NODE_H
16 : #define LLVM_ADT_ILIST_NODE_H
17 :
18 : #include "llvm/ADT/ilist_node_base.h"
19 : #include "llvm/ADT/ilist_node_options.h"
20 :
21 : namespace llvm {
22 :
23 : namespace ilist_detail {
24 :
25 : struct NodeAccess;
26 :
27 : /// Mixin base class that is used to add \a getParent() and
28 : /// \a setParent(ParentTy*) methods to \a ilist_node_impl iff \a ilist_parent
29 : /// has been set in the list options.
30 : template <class NodeTy, class ParentTy> class node_parent_access {
31 : public:
32 : inline const ParentTy *getParent() const {
33 : return static_cast<const NodeTy *>(this)->getNodeBaseParent();
34 : }
35 : inline ParentTy *getParent() {
36 : return static_cast<NodeTy *>(this)->getNodeBaseParent();
37 : }
38 : void setParent(ParentTy *Parent) {
39 : return static_cast<NodeTy *>(this)->setNodeBaseParent(Parent);
40 : }
41 : };
42 : template <class NodeTy> class node_parent_access<NodeTy, void> {};
43 :
44 : } // end namespace ilist_detail
45 :
46 : template <class OptionsT, bool IsReverse, bool IsConst> class ilist_iterator;
47 : template <class OptionsT, bool IsReverse, bool IsConst>
48 : class ilist_iterator_w_bits;
49 : template <class OptionsT> class ilist_sentinel;
50 :
51 : // Selector for which iterator type to pick given the iterator-bits node option.
52 : template <bool use_iterator_bits, typename Opts, bool arg1, bool arg2>
53 : class ilist_select_iterator_type {
54 : public:
55 : using type = ilist_iterator<Opts, arg1, arg2>;
56 : };
57 : template <typename Opts, bool arg1, bool arg2>
58 : class ilist_select_iterator_type<true, Opts, arg1, arg2> {
59 : public:
60 : using type = ilist_iterator_w_bits<Opts, arg1, arg2>;
61 : };
62 :
63 : /// Implementation for an ilist node.
64 : ///
65 : /// Templated on an appropriate \a ilist_detail::node_options, usually computed
66 : /// by \a ilist_detail::compute_node_options.
67 : ///
68 : /// This is a wrapper around \a ilist_node_base whose main purpose is to
69 : /// provide type safety: you can't insert nodes of \a ilist_node_impl into the
70 : /// wrong \a simple_ilist or \a iplist.
71 : template <class OptionsT>
72 : class ilist_node_impl
73 : : OptionsT::node_base_type,
74 : public ilist_detail::node_parent_access<ilist_node_impl<OptionsT>,
75 : typename OptionsT::parent_ty> {
76 : using value_type = typename OptionsT::value_type;
77 : using node_base_type = typename OptionsT::node_base_type;
78 : using list_base_type = typename OptionsT::list_base_type;
79 :
80 : friend typename OptionsT::list_base_type;
81 : friend struct ilist_detail::NodeAccess;
82 : friend class ilist_sentinel<OptionsT>;
83 :
84 : friend class ilist_detail::node_parent_access<ilist_node_impl<OptionsT>,
85 : typename OptionsT::parent_ty>;
86 : friend class ilist_iterator<OptionsT, false, false>;
87 : friend class ilist_iterator<OptionsT, false, true>;
88 : friend class ilist_iterator<OptionsT, true, false>;
89 : friend class ilist_iterator<OptionsT, true, true>;
90 : friend class ilist_iterator_w_bits<OptionsT, false, false>;
91 : friend class ilist_iterator_w_bits<OptionsT, false, true>;
92 : friend class ilist_iterator_w_bits<OptionsT, true, false>;
93 : friend class ilist_iterator_w_bits<OptionsT, true, true>;
94 :
95 : protected:
96 : using self_iterator =
97 : typename ilist_select_iterator_type<OptionsT::has_iterator_bits, OptionsT,
98 : false, false>::type;
99 : using const_self_iterator =
100 : typename ilist_select_iterator_type<OptionsT::has_iterator_bits, OptionsT,
101 : false, true>::type;
102 : using reverse_self_iterator =
103 : typename ilist_select_iterator_type<OptionsT::has_iterator_bits, OptionsT,
104 : true, false>::type;
105 : using const_reverse_self_iterator =
106 : typename ilist_select_iterator_type<OptionsT::has_iterator_bits, OptionsT,
107 : true, true>::type;
108 :
109 : ilist_node_impl() = default;
110 :
111 : private:
112 : ilist_node_impl *getPrev() {
113 : return static_cast<ilist_node_impl *>(node_base_type::getPrev());
114 : }
115 :
116 408014 : ilist_node_impl *getNext() {
117 408014 : return static_cast<ilist_node_impl *>(node_base_type::getNext());
118 : }
119 :
120 : const ilist_node_impl *getPrev() const {
121 : return static_cast<ilist_node_impl *>(node_base_type::getPrev());
122 : }
123 :
124 : const ilist_node_impl *getNext() const {
125 : return static_cast<ilist_node_impl *>(node_base_type::getNext());
126 : }
127 :
128 : void setPrev(ilist_node_impl *N) { node_base_type::setPrev(N); }
129 : void setNext(ilist_node_impl *N) { node_base_type::setNext(N); }
130 :
131 : public:
132 : self_iterator getIterator() { return self_iterator(*this); }
133 : const_self_iterator getIterator() const { return const_self_iterator(*this); }
134 :
135 : reverse_self_iterator getReverseIterator() {
136 : return reverse_self_iterator(*this);
137 : }
138 :
139 : const_reverse_self_iterator getReverseIterator() const {
140 : return const_reverse_self_iterator(*this);
141 : }
142 :
143 : // Under-approximation, but always available for assertions.
144 : using node_base_type::isKnownSentinel;
145 :
146 : /// Check whether this is the sentinel node.
147 : ///
148 : /// This requires sentinel tracking to be explicitly enabled. Use the
149 : /// ilist_sentinel_tracking<true> option to get this API.
150 : bool isSentinel() const {
151 : static_assert(OptionsT::is_sentinel_tracking_explicit,
152 : "Use ilist_sentinel_tracking<true> to enable isSentinel()");
153 : return node_base_type::isSentinel();
154 : }
155 : };
156 :
157 : /// An intrusive list node.
158 : ///
159 : /// A base class to enable membership in intrusive lists, including \a
160 : /// simple_ilist, \a iplist, and \a ilist. The first template parameter is the
161 : /// \a value_type for the list.
162 : ///
163 : /// An ilist node can be configured with compile-time options to change
164 : /// behaviour and/or add API.
165 : ///
166 : /// By default, an \a ilist_node knows whether it is the list sentinel (an
167 : /// instance of \a ilist_sentinel) if and only if
168 : /// LLVM_ENABLE_ABI_BREAKING_CHECKS. The function \a isKnownSentinel() always
169 : /// returns \c false tracking is off. Sentinel tracking steals a bit from the
170 : /// "prev" link, which adds a mask operation when decrementing an iterator, but
171 : /// enables bug-finding assertions in \a ilist_iterator.
172 : ///
173 : /// To turn sentinel tracking on all the time, pass in the
174 : /// ilist_sentinel_tracking<true> template parameter. This also enables the \a
175 : /// isSentinel() function. The same option must be passed to the intrusive
176 : /// list. (ilist_sentinel_tracking<false> turns sentinel tracking off all the
177 : /// time.)
178 : ///
179 : /// A type can inherit from ilist_node multiple times by passing in different
180 : /// \a ilist_tag options. This allows a single instance to be inserted into
181 : /// multiple lists simultaneously, where each list is given the same tag.
182 : ///
183 : /// \example
184 : /// struct A {};
185 : /// struct B {};
186 : /// struct N : ilist_node<N, ilist_tag<A>>, ilist_node<N, ilist_tag<B>> {};
187 : ///
188 : /// void foo() {
189 : /// simple_ilist<N, ilist_tag<A>> ListA;
190 : /// simple_ilist<N, ilist_tag<B>> ListB;
191 : /// N N1;
192 : /// ListA.push_back(N1);
193 : /// ListB.push_back(N1);
194 : /// }
195 : /// \endexample
196 : ///
197 : /// When the \a ilist_parent<ParentTy> option is passed to an ilist_node and the
198 : /// owning ilist, each node contains a pointer to the ilist's owner. This adds
199 : /// \a getParent() and \a setParent(ParentTy*) methods to the ilist_node, which
200 : /// will be used for node access by the ilist if the node class publicly
201 : /// inherits from \a ilist_node_with_parent. By default, setParent() is not
202 : /// automatically called by the ilist; a SymbolTableList will call setParent()
203 : /// on inserted nodes, but the sentinel must still be manually set after the
204 : /// list is created (e.g. SymTabList.end()->setParent(Parent)).
205 : ///
206 : /// The primary benefit of using ilist_parent is that a parent
207 : /// pointer will be stored in the sentinel, meaning that you can safely use \a
208 : /// ilist_iterator::getNodeParent() to get the node parent from any valid (i.e.
209 : /// non-null) iterator, even one that points to a sentinel value.
210 : ///
211 : /// See \a is_valid_option for steps on adding a new option.
212 : template <class T, class... Options>
213 : class ilist_node
214 : : public ilist_node_impl<
215 : typename ilist_detail::compute_node_options<T, Options...>::type> {
216 : static_assert(ilist_detail::check_options<Options...>::value,
217 : "Unrecognized node option!");
218 : };
219 :
220 : namespace ilist_detail {
221 :
222 : /// An access class for ilist_node private API.
223 : ///
224 : /// This gives access to the private parts of ilist nodes. Nodes for an ilist
225 : /// should friend this class if they inherit privately from ilist_node.
226 : ///
227 : /// Using this class outside of the ilist implementation is unsupported.
228 : struct NodeAccess {
229 : protected:
230 : template <class OptionsT>
231 : static ilist_node_impl<OptionsT> *getNodePtr(typename OptionsT::pointer N) {
232 : return N;
233 : }
234 :
235 : template <class OptionsT>
236 : static const ilist_node_impl<OptionsT> *
237 : getNodePtr(typename OptionsT::const_pointer N) {
238 : return N;
239 : }
240 :
241 : template <class OptionsT>
242 345140 : static typename OptionsT::pointer getValuePtr(ilist_node_impl<OptionsT> *N) {
243 345140 : return static_cast<typename OptionsT::pointer>(N);
244 : }
245 :
246 : template <class OptionsT>
247 : static typename OptionsT::const_pointer
248 : getValuePtr(const ilist_node_impl<OptionsT> *N) {
249 : return static_cast<typename OptionsT::const_pointer>(N);
250 : }
251 :
252 : template <class OptionsT>
253 : static ilist_node_impl<OptionsT> *getPrev(ilist_node_impl<OptionsT> &N) {
254 : return N.getPrev();
255 : }
256 :
257 : template <class OptionsT>
258 : static ilist_node_impl<OptionsT> *getNext(ilist_node_impl<OptionsT> &N) {
259 : return N.getNext();
260 : }
261 :
262 : template <class OptionsT>
263 : static const ilist_node_impl<OptionsT> *
264 : getPrev(const ilist_node_impl<OptionsT> &N) {
265 : return N.getPrev();
266 : }
267 :
268 : template <class OptionsT>
269 : static const ilist_node_impl<OptionsT> *
270 : getNext(const ilist_node_impl<OptionsT> &N) {
271 : return N.getNext();
272 : }
273 : };
274 :
275 : template <class OptionsT> struct SpecificNodeAccess : NodeAccess {
276 : protected:
277 : using pointer = typename OptionsT::pointer;
278 : using const_pointer = typename OptionsT::const_pointer;
279 : using node_type = ilist_node_impl<OptionsT>;
280 :
281 : static node_type *getNodePtr(pointer N) {
282 : return NodeAccess::getNodePtr<OptionsT>(N);
283 : }
284 :
285 : static const node_type *getNodePtr(const_pointer N) {
286 : return NodeAccess::getNodePtr<OptionsT>(N);
287 : }
288 :
289 345140 : static pointer getValuePtr(node_type *N) {
290 345140 : return NodeAccess::getValuePtr<OptionsT>(N);
291 : }
292 :
293 : static const_pointer getValuePtr(const node_type *N) {
294 : return NodeAccess::getValuePtr<OptionsT>(N);
295 : }
296 : };
297 :
298 : } // end namespace ilist_detail
299 :
300 : template <class OptionsT>
301 : class ilist_sentinel : public ilist_node_impl<OptionsT> {
302 : public:
303 : ilist_sentinel() {
304 : this->initializeSentinel();
305 : reset();
306 : }
307 :
308 : void reset() {
309 : this->setPrev(this);
310 : this->setNext(this);
311 : }
312 :
313 : bool empty() const { return this == this->getPrev(); }
314 : };
315 :
316 : /// An ilist node that can access its parent list.
317 : ///
318 : /// Requires \c NodeTy to have \a getParent() to find the parent node, and the
319 : /// \c ParentTy to have \a getSublistAccess() to get a reference to the list.
320 : template <typename NodeTy, typename ParentTy, class... Options>
321 : class ilist_node_with_parent : public ilist_node<NodeTy, Options...> {
322 : protected:
323 : ilist_node_with_parent() = default;
324 :
325 : private:
326 : /// Forward to NodeTy::getParent().
327 : ///
328 : /// Note: do not use the name "getParent()". We want a compile error
329 : /// (instead of recursion) when the subclass fails to implement \a
330 : /// getParent().
331 : const ParentTy *getNodeParent() const {
332 : return static_cast<const NodeTy *>(this)->getParent();
333 : }
334 :
335 : public:
336 : /// @name Adjacent Node Accessors
337 : /// @{
338 : /// Get the previous node, or \c nullptr for the list head.
339 : NodeTy *getPrevNode() {
340 : // Should be separated to a reused function, but then we couldn't use auto
341 : // (and would need the type of the list).
342 : const auto &List =
343 : getNodeParent()->*(ParentTy::getSublistAccess((NodeTy *)nullptr));
344 : return List.getPrevNode(*static_cast<NodeTy *>(this));
345 : }
346 :
347 : /// Get the previous node, or \c nullptr for the list head.
348 : const NodeTy *getPrevNode() const {
349 : return const_cast<ilist_node_with_parent *>(this)->getPrevNode();
350 : }
351 :
352 : /// Get the next node, or \c nullptr for the list tail.
353 : NodeTy *getNextNode() {
354 : // Should be separated to a reused function, but then we couldn't use auto
355 : // (and would need the type of the list).
356 : const auto &List =
357 : getNodeParent()->*(ParentTy::getSublistAccess((NodeTy *)nullptr));
358 : return List.getNextNode(*static_cast<NodeTy *>(this));
359 : }
360 :
361 : /// Get the next node, or \c nullptr for the list tail.
362 : const NodeTy *getNextNode() const {
363 : return const_cast<ilist_node_with_parent *>(this)->getNextNode();
364 : }
365 : /// @}
366 : };
367 :
368 : } // end namespace llvm
369 :
370 : #endif // LLVM_ADT_ILIST_NODE_H
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