1 //===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- 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 defines the DenseMap class.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #ifndef LLVM_ADT_DENSEMAP_H
14 #define LLVM_ADT_DENSEMAP_H
15
16 #include "llvm/ADT/DenseMapInfo.h"
17 #include "llvm/ADT/EpochTracker.h"
18 #include "llvm/Support/AlignOf.h"
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/MathExtras.h"
21 #include "llvm/Support/MemAlloc.h"
22 #include "llvm/Support/ReverseIteration.h"
23 #include "llvm/Support/type_traits.h"
24 #include <algorithm>
25 #include <cassert>
26 #include <cstddef>
27 #include <cstring>
28 #include <initializer_list>
29 #include <iterator>
30 #include <new>
31 #include <type_traits>
32 #include <utility>
33
34 namespace llvm {
35
36 namespace detail {
37
38 // We extend a pair to allow users to override the bucket type with their own
39 // implementation without requiring two members.
40 template <typename KeyT, typename ValueT>
41 struct DenseMapPair : public std::pair<KeyT, ValueT> {
42 using std::pair<KeyT, ValueT>::pair;
43
getFirstDenseMapPair44 KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
getFirstDenseMapPair45 const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; }
getSecondDenseMapPair46 ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; }
getSecondDenseMapPair47 const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; }
48 };
49
50 } // end namespace detail
51
52 template <typename KeyT, typename ValueT,
53 typename KeyInfoT = DenseMapInfo<KeyT>,
54 typename Bucket = llvm::detail::DenseMapPair<KeyT, ValueT>,
55 bool IsConst = false>
56 class DenseMapIterator;
57
58 template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
59 typename BucketT>
60 class DenseMapBase : public DebugEpochBase {
61 template <typename T>
62 using const_arg_type_t = typename const_pointer_or_const_ref<T>::type;
63
64 public:
65 using size_type = unsigned;
66 using key_type = KeyT;
67 using mapped_type = ValueT;
68 using value_type = BucketT;
69
70 using iterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT>;
71 using const_iterator =
72 DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>;
73
begin()74 inline iterator begin() {
75 // When the map is empty, avoid the overhead of advancing/retreating past
76 // empty buckets.
77 if (empty())
78 return end();
79 if (shouldReverseIterate<KeyT>())
80 return makeIterator(getBucketsEnd() - 1, getBuckets(), *this);
81 return makeIterator(getBuckets(), getBucketsEnd(), *this);
82 }
end()83 inline iterator end() {
84 return makeIterator(getBucketsEnd(), getBucketsEnd(), *this, true);
85 }
begin()86 inline const_iterator begin() const {
87 if (empty())
88 return end();
89 if (shouldReverseIterate<KeyT>())
90 return makeConstIterator(getBucketsEnd() - 1, getBuckets(), *this);
91 return makeConstIterator(getBuckets(), getBucketsEnd(), *this);
92 }
end()93 inline const_iterator end() const {
94 return makeConstIterator(getBucketsEnd(), getBucketsEnd(), *this, true);
95 }
96
empty()97 LLVM_NODISCARD bool empty() const {
98 return getNumEntries() == 0;
99 }
size()100 unsigned size() const { return getNumEntries(); }
101
102 /// Grow the densemap so that it can contain at least \p NumEntries items
103 /// before resizing again.
reserve(size_type NumEntries)104 void reserve(size_type NumEntries) {
105 auto NumBuckets = getMinBucketToReserveForEntries(NumEntries);
106 incrementEpoch();
107 if (NumBuckets > getNumBuckets())
108 grow(NumBuckets);
109 }
110
clear()111 void clear() {
112 incrementEpoch();
113 if (getNumEntries() == 0 && getNumTombstones() == 0) return;
114
115 // If the capacity of the array is huge, and the # elements used is small,
116 // shrink the array.
117 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) {
118 shrink_and_clear();
119 return;
120 }
121
122 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
123 if (std::is_trivially_destructible<ValueT>::value) {
124 // Use a simpler loop when values don't need destruction.
125 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P)
126 P->getFirst() = EmptyKey;
127 } else {
128 unsigned NumEntries = getNumEntries();
129 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
130 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
131 if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
132 P->getSecond().~ValueT();
133 --NumEntries;
134 }
135 P->getFirst() = EmptyKey;
136 }
137 }
138 assert(NumEntries == 0 && "Node count imbalance!");
139 }
140 setNumEntries(0);
141 setNumTombstones(0);
142 }
143
144 /// Return 1 if the specified key is in the map, 0 otherwise.
count(const_arg_type_t<KeyT> Val)145 size_type count(const_arg_type_t<KeyT> Val) const {
146 const BucketT *TheBucket;
147 return LookupBucketFor(Val, TheBucket) ? 1 : 0;
148 }
149
find(const_arg_type_t<KeyT> Val)150 iterator find(const_arg_type_t<KeyT> Val) {
151 BucketT *TheBucket;
152 if (LookupBucketFor(Val, TheBucket))
153 return makeIterator(TheBucket,
154 shouldReverseIterate<KeyT>() ? getBuckets()
155 : getBucketsEnd(),
156 *this, true);
157 return end();
158 }
find(const_arg_type_t<KeyT> Val)159 const_iterator find(const_arg_type_t<KeyT> Val) const {
160 const BucketT *TheBucket;
161 if (LookupBucketFor(Val, TheBucket))
162 return makeConstIterator(TheBucket,
163 shouldReverseIterate<KeyT>() ? getBuckets()
164 : getBucketsEnd(),
165 *this, true);
166 return end();
167 }
168
169 /// Alternate version of find() which allows a different, and possibly
170 /// less expensive, key type.
171 /// The DenseMapInfo is responsible for supplying methods
172 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
173 /// type used.
174 template<class LookupKeyT>
find_as(const LookupKeyT & Val)175 iterator find_as(const LookupKeyT &Val) {
176 BucketT *TheBucket;
177 if (LookupBucketFor(Val, TheBucket))
178 return makeIterator(TheBucket,
179 shouldReverseIterate<KeyT>() ? getBuckets()
180 : getBucketsEnd(),
181 *this, true);
182 return end();
183 }
184 template<class LookupKeyT>
find_as(const LookupKeyT & Val)185 const_iterator find_as(const LookupKeyT &Val) const {
186 const BucketT *TheBucket;
187 if (LookupBucketFor(Val, TheBucket))
188 return makeConstIterator(TheBucket,
189 shouldReverseIterate<KeyT>() ? getBuckets()
190 : getBucketsEnd(),
191 *this, true);
192 return end();
193 }
194
195 /// lookup - Return the entry for the specified key, or a default
196 /// constructed value if no such entry exists.
lookup(const_arg_type_t<KeyT> Val)197 ValueT lookup(const_arg_type_t<KeyT> Val) const {
198 const BucketT *TheBucket;
199 if (LookupBucketFor(Val, TheBucket))
200 return TheBucket->getSecond();
201 return ValueT();
202 }
203
204 // Inserts key,value pair into the map if the key isn't already in the map.
205 // If the key is already in the map, it returns false and doesn't update the
206 // value.
insert(const std::pair<KeyT,ValueT> & KV)207 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
208 return try_emplace(KV.first, KV.second);
209 }
210
211 // Inserts key,value pair into the map if the key isn't already in the map.
212 // If the key is already in the map, it returns false and doesn't update the
213 // value.
insert(std::pair<KeyT,ValueT> && KV)214 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
215 return try_emplace(std::move(KV.first), std::move(KV.second));
216 }
217
218 // Inserts key,value pair into the map if the key isn't already in the map.
219 // The value is constructed in-place if the key is not in the map, otherwise
220 // it is not moved.
221 template <typename... Ts>
try_emplace(KeyT && Key,Ts &&...Args)222 std::pair<iterator, bool> try_emplace(KeyT &&Key, Ts &&... Args) {
223 BucketT *TheBucket;
224 if (LookupBucketFor(Key, TheBucket))
225 return std::make_pair(makeIterator(TheBucket,
226 shouldReverseIterate<KeyT>()
227 ? getBuckets()
228 : getBucketsEnd(),
229 *this, true),
230 false); // Already in map.
231
232 // Otherwise, insert the new element.
233 TheBucket =
234 InsertIntoBucket(TheBucket, std::move(Key), std::forward<Ts>(Args)...);
235 return std::make_pair(makeIterator(TheBucket,
236 shouldReverseIterate<KeyT>()
237 ? getBuckets()
238 : getBucketsEnd(),
239 *this, true),
240 true);
241 }
242
243 // Inserts key,value pair into the map if the key isn't already in the map.
244 // The value is constructed in-place if the key is not in the map, otherwise
245 // it is not moved.
246 template <typename... Ts>
try_emplace(const KeyT & Key,Ts &&...Args)247 std::pair<iterator, bool> try_emplace(const KeyT &Key, Ts &&... Args) {
248 BucketT *TheBucket;
249 if (LookupBucketFor(Key, TheBucket))
250 return std::make_pair(makeIterator(TheBucket,
251 shouldReverseIterate<KeyT>()
252 ? getBuckets()
253 : getBucketsEnd(),
254 *this, true),
255 false); // Already in map.
256
257 // Otherwise, insert the new element.
258 TheBucket = InsertIntoBucket(TheBucket, Key, std::forward<Ts>(Args)...);
259 return std::make_pair(makeIterator(TheBucket,
260 shouldReverseIterate<KeyT>()
261 ? getBuckets()
262 : getBucketsEnd(),
263 *this, true),
264 true);
265 }
266
267 /// Alternate version of insert() which allows a different, and possibly
268 /// less expensive, key type.
269 /// The DenseMapInfo is responsible for supplying methods
270 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
271 /// type used.
272 template <typename LookupKeyT>
insert_as(std::pair<KeyT,ValueT> && KV,const LookupKeyT & Val)273 std::pair<iterator, bool> insert_as(std::pair<KeyT, ValueT> &&KV,
274 const LookupKeyT &Val) {
275 BucketT *TheBucket;
276 if (LookupBucketFor(Val, TheBucket))
277 return std::make_pair(makeIterator(TheBucket,
278 shouldReverseIterate<KeyT>()
279 ? getBuckets()
280 : getBucketsEnd(),
281 *this, true),
282 false); // Already in map.
283
284 // Otherwise, insert the new element.
285 TheBucket = InsertIntoBucketWithLookup(TheBucket, std::move(KV.first),
286 std::move(KV.second), Val);
287 return std::make_pair(makeIterator(TheBucket,
288 shouldReverseIterate<KeyT>()
289 ? getBuckets()
290 : getBucketsEnd(),
291 *this, true),
292 true);
293 }
294
295 /// insert - Range insertion of pairs.
296 template<typename InputIt>
insert(InputIt I,InputIt E)297 void insert(InputIt I, InputIt E) {
298 for (; I != E; ++I)
299 insert(*I);
300 }
301
erase(const KeyT & Val)302 bool erase(const KeyT &Val) {
303 BucketT *TheBucket;
304 if (!LookupBucketFor(Val, TheBucket))
305 return false; // not in map.
306
307 TheBucket->getSecond().~ValueT();
308 TheBucket->getFirst() = getTombstoneKey();
309 decrementNumEntries();
310 incrementNumTombstones();
311 return true;
312 }
erase(iterator I)313 void erase(iterator I) {
314 BucketT *TheBucket = &*I;
315 TheBucket->getSecond().~ValueT();
316 TheBucket->getFirst() = getTombstoneKey();
317 decrementNumEntries();
318 incrementNumTombstones();
319 }
320
FindAndConstruct(const KeyT & Key)321 value_type& FindAndConstruct(const KeyT &Key) {
322 BucketT *TheBucket;
323 if (LookupBucketFor(Key, TheBucket))
324 return *TheBucket;
325
326 return *InsertIntoBucket(TheBucket, Key);
327 }
328
329 ValueT &operator[](const KeyT &Key) {
330 return FindAndConstruct(Key).second;
331 }
332
FindAndConstruct(KeyT && Key)333 value_type& FindAndConstruct(KeyT &&Key) {
334 BucketT *TheBucket;
335 if (LookupBucketFor(Key, TheBucket))
336 return *TheBucket;
337
338 return *InsertIntoBucket(TheBucket, std::move(Key));
339 }
340
341 ValueT &operator[](KeyT &&Key) {
342 return FindAndConstruct(std::move(Key)).second;
343 }
344
345 /// isPointerIntoBucketsArray - Return true if the specified pointer points
346 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or
347 /// value in the DenseMap).
isPointerIntoBucketsArray(const void * Ptr)348 bool isPointerIntoBucketsArray(const void *Ptr) const {
349 return Ptr >= getBuckets() && Ptr < getBucketsEnd();
350 }
351
352 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
353 /// array. In conjunction with the previous method, this can be used to
354 /// determine whether an insertion caused the DenseMap to reallocate.
getPointerIntoBucketsArray()355 const void *getPointerIntoBucketsArray() const { return getBuckets(); }
356
357 protected:
358 DenseMapBase() = default;
359
destroyAll()360 void destroyAll() {
361 if (getNumBuckets() == 0) // Nothing to do.
362 return;
363
364 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
365 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
366 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
367 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
368 P->getSecond().~ValueT();
369 P->getFirst().~KeyT();
370 }
371 }
372
initEmpty()373 void initEmpty() {
374 setNumEntries(0);
375 setNumTombstones(0);
376
377 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&
378 "# initial buckets must be a power of two!");
379 const KeyT EmptyKey = getEmptyKey();
380 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
381 ::new (&B->getFirst()) KeyT(EmptyKey);
382 }
383
384 /// Returns the number of buckets to allocate to ensure that the DenseMap can
385 /// accommodate \p NumEntries without need to grow().
getMinBucketToReserveForEntries(unsigned NumEntries)386 unsigned getMinBucketToReserveForEntries(unsigned NumEntries) {
387 // Ensure that "NumEntries * 4 < NumBuckets * 3"
388 if (NumEntries == 0)
389 return 0;
390 // +1 is required because of the strict equality.
391 // For example if NumEntries is 48, we need to return 401.
392 return NextPowerOf2(NumEntries * 4 / 3 + 1);
393 }
394
moveFromOldBuckets(BucketT * OldBucketsBegin,BucketT * OldBucketsEnd)395 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
396 initEmpty();
397
398 // Insert all the old elements.
399 const KeyT EmptyKey = getEmptyKey();
400 const KeyT TombstoneKey = getTombstoneKey();
401 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
402 if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) &&
403 !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) {
404 // Insert the key/value into the new table.
405 BucketT *DestBucket;
406 bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket);
407 (void)FoundVal; // silence warning.
408 assert(!FoundVal && "Key already in new map?");
409 DestBucket->getFirst() = std::move(B->getFirst());
410 ::new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
411 incrementNumEntries();
412
413 // Free the value.
414 B->getSecond().~ValueT();
415 }
416 B->getFirst().~KeyT();
417 }
418 }
419
420 template <typename OtherBaseT>
copyFrom(const DenseMapBase<OtherBaseT,KeyT,ValueT,KeyInfoT,BucketT> & other)421 void copyFrom(
422 const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
423 assert(&other != this);
424 assert(getNumBuckets() == other.getNumBuckets());
425
426 setNumEntries(other.getNumEntries());
427 setNumTombstones(other.getNumTombstones());
428
429 if (std::is_trivially_copyable<KeyT>::value &&
430 std::is_trivially_copyable<ValueT>::value)
431 memcpy(reinterpret_cast<void *>(getBuckets()), other.getBuckets(),
432 getNumBuckets() * sizeof(BucketT));
433 else
434 for (size_t i = 0; i < getNumBuckets(); ++i) {
435 ::new (&getBuckets()[i].getFirst())
436 KeyT(other.getBuckets()[i].getFirst());
437 if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) &&
438 !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey()))
439 ::new (&getBuckets()[i].getSecond())
440 ValueT(other.getBuckets()[i].getSecond());
441 }
442 }
443
getHashValue(const KeyT & Val)444 static unsigned getHashValue(const KeyT &Val) {
445 return KeyInfoT::getHashValue(Val);
446 }
447
448 template<typename LookupKeyT>
getHashValue(const LookupKeyT & Val)449 static unsigned getHashValue(const LookupKeyT &Val) {
450 return KeyInfoT::getHashValue(Val);
451 }
452
getEmptyKey()453 static const KeyT getEmptyKey() {
454 static_assert(std::is_base_of<DenseMapBase, DerivedT>::value,
455 "Must pass the derived type to this template!");
456 return KeyInfoT::getEmptyKey();
457 }
458
getTombstoneKey()459 static const KeyT getTombstoneKey() {
460 return KeyInfoT::getTombstoneKey();
461 }
462
463 private:
464 iterator makeIterator(BucketT *P, BucketT *E,
465 DebugEpochBase &Epoch,
466 bool NoAdvance=false) {
467 if (shouldReverseIterate<KeyT>()) {
468 BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1;
469 return iterator(B, E, Epoch, NoAdvance);
470 }
471 return iterator(P, E, Epoch, NoAdvance);
472 }
473
474 const_iterator makeConstIterator(const BucketT *P, const BucketT *E,
475 const DebugEpochBase &Epoch,
476 const bool NoAdvance=false) const {
477 if (shouldReverseIterate<KeyT>()) {
478 const BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1;
479 return const_iterator(B, E, Epoch, NoAdvance);
480 }
481 return const_iterator(P, E, Epoch, NoAdvance);
482 }
483
getNumEntries()484 unsigned getNumEntries() const {
485 return static_cast<const DerivedT *>(this)->getNumEntries();
486 }
487
setNumEntries(unsigned Num)488 void setNumEntries(unsigned Num) {
489 static_cast<DerivedT *>(this)->setNumEntries(Num);
490 }
491
incrementNumEntries()492 void incrementNumEntries() {
493 setNumEntries(getNumEntries() + 1);
494 }
495
decrementNumEntries()496 void decrementNumEntries() {
497 setNumEntries(getNumEntries() - 1);
498 }
499
getNumTombstones()500 unsigned getNumTombstones() const {
501 return static_cast<const DerivedT *>(this)->getNumTombstones();
502 }
503
setNumTombstones(unsigned Num)504 void setNumTombstones(unsigned Num) {
505 static_cast<DerivedT *>(this)->setNumTombstones(Num);
506 }
507
incrementNumTombstones()508 void incrementNumTombstones() {
509 setNumTombstones(getNumTombstones() + 1);
510 }
511
decrementNumTombstones()512 void decrementNumTombstones() {
513 setNumTombstones(getNumTombstones() - 1);
514 }
515
getBuckets()516 const BucketT *getBuckets() const {
517 return static_cast<const DerivedT *>(this)->getBuckets();
518 }
519
getBuckets()520 BucketT *getBuckets() {
521 return static_cast<DerivedT *>(this)->getBuckets();
522 }
523
getNumBuckets()524 unsigned getNumBuckets() const {
525 return static_cast<const DerivedT *>(this)->getNumBuckets();
526 }
527
getBucketsEnd()528 BucketT *getBucketsEnd() {
529 return getBuckets() + getNumBuckets();
530 }
531
getBucketsEnd()532 const BucketT *getBucketsEnd() const {
533 return getBuckets() + getNumBuckets();
534 }
535
grow(unsigned AtLeast)536 void grow(unsigned AtLeast) {
537 static_cast<DerivedT *>(this)->grow(AtLeast);
538 }
539
shrink_and_clear()540 void shrink_and_clear() {
541 static_cast<DerivedT *>(this)->shrink_and_clear();
542 }
543
544 template <typename KeyArg, typename... ValueArgs>
InsertIntoBucket(BucketT * TheBucket,KeyArg && Key,ValueArgs &&...Values)545 BucketT *InsertIntoBucket(BucketT *TheBucket, KeyArg &&Key,
546 ValueArgs &&... Values) {
547 TheBucket = InsertIntoBucketImpl(Key, Key, TheBucket);
548
549 TheBucket->getFirst() = std::forward<KeyArg>(Key);
550 ::new (&TheBucket->getSecond()) ValueT(std::forward<ValueArgs>(Values)...);
551 return TheBucket;
552 }
553
554 template <typename LookupKeyT>
InsertIntoBucketWithLookup(BucketT * TheBucket,KeyT && Key,ValueT && Value,LookupKeyT & Lookup)555 BucketT *InsertIntoBucketWithLookup(BucketT *TheBucket, KeyT &&Key,
556 ValueT &&Value, LookupKeyT &Lookup) {
557 TheBucket = InsertIntoBucketImpl(Key, Lookup, TheBucket);
558
559 TheBucket->getFirst() = std::move(Key);
560 ::new (&TheBucket->getSecond()) ValueT(std::move(Value));
561 return TheBucket;
562 }
563
564 template <typename LookupKeyT>
InsertIntoBucketImpl(const KeyT & Key,const LookupKeyT & Lookup,BucketT * TheBucket)565 BucketT *InsertIntoBucketImpl(const KeyT &Key, const LookupKeyT &Lookup,
566 BucketT *TheBucket) {
567 incrementEpoch();
568
569 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of
570 // the buckets are empty (meaning that many are filled with tombstones),
571 // grow the table.
572 //
573 // The later case is tricky. For example, if we had one empty bucket with
574 // tons of tombstones, failing lookups (e.g. for insertion) would have to
575 // probe almost the entire table until it found the empty bucket. If the
576 // table completely filled with tombstones, no lookup would ever succeed,
577 // causing infinite loops in lookup.
578 unsigned NewNumEntries = getNumEntries() + 1;
579 unsigned NumBuckets = getNumBuckets();
580 if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)) {
581 this->grow(NumBuckets * 2);
582 LookupBucketFor(Lookup, TheBucket);
583 NumBuckets = getNumBuckets();
584 } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=
585 NumBuckets/8)) {
586 this->grow(NumBuckets);
587 LookupBucketFor(Lookup, TheBucket);
588 }
589 assert(TheBucket);
590
591 // Only update the state after we've grown our bucket space appropriately
592 // so that when growing buckets we have self-consistent entry count.
593 incrementNumEntries();
594
595 // If we are writing over a tombstone, remember this.
596 const KeyT EmptyKey = getEmptyKey();
597 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
598 decrementNumTombstones();
599
600 return TheBucket;
601 }
602
603 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
604 /// FoundBucket. If the bucket contains the key and a value, this returns
605 /// true, otherwise it returns a bucket with an empty marker or tombstone and
606 /// returns false.
607 template<typename LookupKeyT>
LookupBucketFor(const LookupKeyT & Val,const BucketT * & FoundBucket)608 bool LookupBucketFor(const LookupKeyT &Val,
609 const BucketT *&FoundBucket) const {
610 const BucketT *BucketsPtr = getBuckets();
611 const unsigned NumBuckets = getNumBuckets();
612
613 if (NumBuckets == 0) {
614 FoundBucket = nullptr;
615 return false;
616 }
617
618 // FoundTombstone - Keep track of whether we find a tombstone while probing.
619 const BucketT *FoundTombstone = nullptr;
620 const KeyT EmptyKey = getEmptyKey();
621 const KeyT TombstoneKey = getTombstoneKey();
622 assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
623 !KeyInfoT::isEqual(Val, TombstoneKey) &&
624 "Empty/Tombstone value shouldn't be inserted into map!");
625
626 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
627 unsigned ProbeAmt = 1;
628 while (true) {
629 const BucketT *ThisBucket = BucketsPtr + BucketNo;
630 // Found Val's bucket? If so, return it.
631 if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))) {
632 FoundBucket = ThisBucket;
633 return true;
634 }
635
636 // If we found an empty bucket, the key doesn't exist in the set.
637 // Insert it and return the default value.
638 if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))) {
639 // If we've already seen a tombstone while probing, fill it in instead
640 // of the empty bucket we eventually probed to.
641 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
642 return false;
643 }
644
645 // If this is a tombstone, remember it. If Val ends up not in the map, we
646 // prefer to return it than something that would require more probing.
647 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
648 !FoundTombstone)
649 FoundTombstone = ThisBucket; // Remember the first tombstone found.
650
651 // Otherwise, it's a hash collision or a tombstone, continue quadratic
652 // probing.
653 BucketNo += ProbeAmt++;
654 BucketNo &= (NumBuckets-1);
655 }
656 }
657
658 template <typename LookupKeyT>
LookupBucketFor(const LookupKeyT & Val,BucketT * & FoundBucket)659 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
660 const BucketT *ConstFoundBucket;
661 bool Result = const_cast<const DenseMapBase *>(this)
662 ->LookupBucketFor(Val, ConstFoundBucket);
663 FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
664 return Result;
665 }
666
667 public:
668 /// Return the approximate size (in bytes) of the actual map.
669 /// This is just the raw memory used by DenseMap.
670 /// If entries are pointers to objects, the size of the referenced objects
671 /// are not included.
getMemorySize()672 size_t getMemorySize() const {
673 return getNumBuckets() * sizeof(BucketT);
674 }
675 };
676
677 /// Equality comparison for DenseMap.
678 ///
679 /// Iterates over elements of LHS confirming that each (key, value) pair in LHS
680 /// is also in RHS, and that no additional pairs are in RHS.
681 /// Equivalent to N calls to RHS.find and N value comparisons. Amortized
682 /// complexity is linear, worst case is O(N^2) (if every hash collides).
683 template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
684 typename BucketT>
685 bool operator==(
686 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &LHS,
687 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &RHS) {
688 if (LHS.size() != RHS.size())
689 return false;
690
691 for (auto &KV : LHS) {
692 auto I = RHS.find(KV.first);
693 if (I == RHS.end() || I->second != KV.second)
694 return false;
695 }
696
697 return true;
698 }
699
700 /// Inequality comparison for DenseMap.
701 ///
702 /// Equivalent to !(LHS == RHS). See operator== for performance notes.
703 template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
704 typename BucketT>
705 bool operator!=(
706 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &LHS,
707 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &RHS) {
708 return !(LHS == RHS);
709 }
710
711 template <typename KeyT, typename ValueT,
712 typename KeyInfoT = DenseMapInfo<KeyT>,
713 typename BucketT = llvm::detail::DenseMapPair<KeyT, ValueT>>
714 class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
715 KeyT, ValueT, KeyInfoT, BucketT> {
716 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
717
718 // Lift some types from the dependent base class into this class for
719 // simplicity of referring to them.
720 using BaseT = DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
721
722 BucketT *Buckets;
723 unsigned NumEntries;
724 unsigned NumTombstones;
725 unsigned NumBuckets;
726
727 public:
728 /// Create a DenseMap with an optional \p InitialReserve that guarantee that
729 /// this number of elements can be inserted in the map without grow()
730 explicit DenseMap(unsigned InitialReserve = 0) { init(InitialReserve); }
731
DenseMap(const DenseMap & other)732 DenseMap(const DenseMap &other) : BaseT() {
733 init(0);
734 copyFrom(other);
735 }
736
DenseMap(DenseMap && other)737 DenseMap(DenseMap &&other) : BaseT() {
738 init(0);
739 swap(other);
740 }
741
742 template<typename InputIt>
DenseMap(const InputIt & I,const InputIt & E)743 DenseMap(const InputIt &I, const InputIt &E) {
744 init(std::distance(I, E));
745 this->insert(I, E);
746 }
747
DenseMap(std::initializer_list<typename BaseT::value_type> Vals)748 DenseMap(std::initializer_list<typename BaseT::value_type> Vals) {
749 init(Vals.size());
750 this->insert(Vals.begin(), Vals.end());
751 }
752
~DenseMap()753 ~DenseMap() {
754 this->destroyAll();
755 deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT));
756 }
757
swap(DenseMap & RHS)758 void swap(DenseMap& RHS) {
759 this->incrementEpoch();
760 RHS.incrementEpoch();
761 std::swap(Buckets, RHS.Buckets);
762 std::swap(NumEntries, RHS.NumEntries);
763 std::swap(NumTombstones, RHS.NumTombstones);
764 std::swap(NumBuckets, RHS.NumBuckets);
765 }
766
767 DenseMap& operator=(const DenseMap& other) {
768 if (&other != this)
769 copyFrom(other);
770 return *this;
771 }
772
773 DenseMap& operator=(DenseMap &&other) {
774 this->destroyAll();
775 deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT));
776 init(0);
777 swap(other);
778 return *this;
779 }
780
copyFrom(const DenseMap & other)781 void copyFrom(const DenseMap& other) {
782 this->destroyAll();
783 deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT));
784 if (allocateBuckets(other.NumBuckets)) {
785 this->BaseT::copyFrom(other);
786 } else {
787 NumEntries = 0;
788 NumTombstones = 0;
789 }
790 }
791
init(unsigned InitNumEntries)792 void init(unsigned InitNumEntries) {
793 auto InitBuckets = BaseT::getMinBucketToReserveForEntries(InitNumEntries);
794 if (allocateBuckets(InitBuckets)) {
795 this->BaseT::initEmpty();
796 } else {
797 NumEntries = 0;
798 NumTombstones = 0;
799 }
800 }
801
grow(unsigned AtLeast)802 void grow(unsigned AtLeast) {
803 unsigned OldNumBuckets = NumBuckets;
804 BucketT *OldBuckets = Buckets;
805
806 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
807 assert(Buckets);
808 if (!OldBuckets) {
809 this->BaseT::initEmpty();
810 return;
811 }
812
813 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
814
815 // Free the old table.
816 deallocate_buffer(OldBuckets, sizeof(BucketT) * OldNumBuckets,
817 alignof(BucketT));
818 }
819
shrink_and_clear()820 void shrink_and_clear() {
821 unsigned OldNumBuckets = NumBuckets;
822 unsigned OldNumEntries = NumEntries;
823 this->destroyAll();
824
825 // Reduce the number of buckets.
826 unsigned NewNumBuckets = 0;
827 if (OldNumEntries)
828 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
829 if (NewNumBuckets == NumBuckets) {
830 this->BaseT::initEmpty();
831 return;
832 }
833
834 deallocate_buffer(Buckets, sizeof(BucketT) * OldNumBuckets,
835 alignof(BucketT));
836 init(NewNumBuckets);
837 }
838
839 private:
getNumEntries()840 unsigned getNumEntries() const {
841 return NumEntries;
842 }
843
setNumEntries(unsigned Num)844 void setNumEntries(unsigned Num) {
845 NumEntries = Num;
846 }
847
getNumTombstones()848 unsigned getNumTombstones() const {
849 return NumTombstones;
850 }
851
setNumTombstones(unsigned Num)852 void setNumTombstones(unsigned Num) {
853 NumTombstones = Num;
854 }
855
getBuckets()856 BucketT *getBuckets() const {
857 return Buckets;
858 }
859
getNumBuckets()860 unsigned getNumBuckets() const {
861 return NumBuckets;
862 }
863
allocateBuckets(unsigned Num)864 bool allocateBuckets(unsigned Num) {
865 NumBuckets = Num;
866 if (NumBuckets == 0) {
867 Buckets = nullptr;
868 return false;
869 }
870
871 Buckets = static_cast<BucketT *>(
872 allocate_buffer(sizeof(BucketT) * NumBuckets, alignof(BucketT)));
873 return true;
874 }
875 };
876
877 template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
878 typename KeyInfoT = DenseMapInfo<KeyT>,
879 typename BucketT = llvm::detail::DenseMapPair<KeyT, ValueT>>
880 class SmallDenseMap
881 : public DenseMapBase<
882 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
883 ValueT, KeyInfoT, BucketT> {
884 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
885
886 // Lift some types from the dependent base class into this class for
887 // simplicity of referring to them.
888 using BaseT = DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
889
890 static_assert(isPowerOf2_64(InlineBuckets),
891 "InlineBuckets must be a power of 2.");
892
893 unsigned Small : 1;
894 unsigned NumEntries : 31;
895 unsigned NumTombstones;
896
897 struct LargeRep {
898 BucketT *Buckets;
899 unsigned NumBuckets;
900 };
901
902 /// A "union" of an inline bucket array and the struct representing
903 /// a large bucket. This union will be discriminated by the 'Small' bit.
904 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
905
906 public:
907 explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
908 init(NumInitBuckets);
909 }
910
SmallDenseMap(const SmallDenseMap & other)911 SmallDenseMap(const SmallDenseMap &other) : BaseT() {
912 init(0);
913 copyFrom(other);
914 }
915
SmallDenseMap(SmallDenseMap && other)916 SmallDenseMap(SmallDenseMap &&other) : BaseT() {
917 init(0);
918 swap(other);
919 }
920
921 template<typename InputIt>
SmallDenseMap(const InputIt & I,const InputIt & E)922 SmallDenseMap(const InputIt &I, const InputIt &E) {
923 init(NextPowerOf2(std::distance(I, E)));
924 this->insert(I, E);
925 }
926
SmallDenseMap(std::initializer_list<typename BaseT::value_type> Vals)927 SmallDenseMap(std::initializer_list<typename BaseT::value_type> Vals)
928 : SmallDenseMap(Vals.begin(), Vals.end()) {}
929
~SmallDenseMap()930 ~SmallDenseMap() {
931 this->destroyAll();
932 deallocateBuckets();
933 }
934
swap(SmallDenseMap & RHS)935 void swap(SmallDenseMap& RHS) {
936 unsigned TmpNumEntries = RHS.NumEntries;
937 RHS.NumEntries = NumEntries;
938 NumEntries = TmpNumEntries;
939 std::swap(NumTombstones, RHS.NumTombstones);
940
941 const KeyT EmptyKey = this->getEmptyKey();
942 const KeyT TombstoneKey = this->getTombstoneKey();
943 if (Small && RHS.Small) {
944 // If we're swapping inline bucket arrays, we have to cope with some of
945 // the tricky bits of DenseMap's storage system: the buckets are not
946 // fully initialized. Thus we swap every key, but we may have
947 // a one-directional move of the value.
948 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
949 BucketT *LHSB = &getInlineBuckets()[i],
950 *RHSB = &RHS.getInlineBuckets()[i];
951 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
952 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
953 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
954 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
955 if (hasLHSValue && hasRHSValue) {
956 // Swap together if we can...
957 std::swap(*LHSB, *RHSB);
958 continue;
959 }
960 // Swap separately and handle any asymmetry.
961 std::swap(LHSB->getFirst(), RHSB->getFirst());
962 if (hasLHSValue) {
963 ::new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
964 LHSB->getSecond().~ValueT();
965 } else if (hasRHSValue) {
966 ::new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
967 RHSB->getSecond().~ValueT();
968 }
969 }
970 return;
971 }
972 if (!Small && !RHS.Small) {
973 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
974 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
975 return;
976 }
977
978 SmallDenseMap &SmallSide = Small ? *this : RHS;
979 SmallDenseMap &LargeSide = Small ? RHS : *this;
980
981 // First stash the large side's rep and move the small side across.
982 LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
983 LargeSide.getLargeRep()->~LargeRep();
984 LargeSide.Small = true;
985 // This is similar to the standard move-from-old-buckets, but the bucket
986 // count hasn't actually rotated in this case. So we have to carefully
987 // move construct the keys and values into their new locations, but there
988 // is no need to re-hash things.
989 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
990 BucketT *NewB = &LargeSide.getInlineBuckets()[i],
991 *OldB = &SmallSide.getInlineBuckets()[i];
992 ::new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
993 OldB->getFirst().~KeyT();
994 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
995 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
996 ::new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
997 OldB->getSecond().~ValueT();
998 }
999 }
1000
1001 // The hard part of moving the small buckets across is done, just move
1002 // the TmpRep into its new home.
1003 SmallSide.Small = false;
1004 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
1005 }
1006
1007 SmallDenseMap& operator=(const SmallDenseMap& other) {
1008 if (&other != this)
1009 copyFrom(other);
1010 return *this;
1011 }
1012
1013 SmallDenseMap& operator=(SmallDenseMap &&other) {
1014 this->destroyAll();
1015 deallocateBuckets();
1016 init(0);
1017 swap(other);
1018 return *this;
1019 }
1020
copyFrom(const SmallDenseMap & other)1021 void copyFrom(const SmallDenseMap& other) {
1022 this->destroyAll();
1023 deallocateBuckets();
1024 Small = true;
1025 if (other.getNumBuckets() > InlineBuckets) {
1026 Small = false;
1027 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
1028 }
1029 this->BaseT::copyFrom(other);
1030 }
1031
init(unsigned InitBuckets)1032 void init(unsigned InitBuckets) {
1033 Small = true;
1034 if (InitBuckets > InlineBuckets) {
1035 Small = false;
1036 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
1037 }
1038 this->BaseT::initEmpty();
1039 }
1040
grow(unsigned AtLeast)1041 void grow(unsigned AtLeast) {
1042 if (AtLeast > InlineBuckets)
1043 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
1044
1045 if (Small) {
1046 // First move the inline buckets into a temporary storage.
1047 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
1048 BucketT *TmpBegin = reinterpret_cast<BucketT *>(&TmpStorage);
1049 BucketT *TmpEnd = TmpBegin;
1050
1051 // Loop over the buckets, moving non-empty, non-tombstones into the
1052 // temporary storage. Have the loop move the TmpEnd forward as it goes.
1053 const KeyT EmptyKey = this->getEmptyKey();
1054 const KeyT TombstoneKey = this->getTombstoneKey();
1055 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
1056 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
1057 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
1058 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
1059 "Too many inline buckets!");
1060 ::new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
1061 ::new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
1062 ++TmpEnd;
1063 P->getSecond().~ValueT();
1064 }
1065 P->getFirst().~KeyT();
1066 }
1067
1068 // AtLeast == InlineBuckets can happen if there are many tombstones,
1069 // and grow() is used to remove them. Usually we always switch to the
1070 // large rep here.
1071 if (AtLeast > InlineBuckets) {
1072 Small = false;
1073 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
1074 }
1075 this->moveFromOldBuckets(TmpBegin, TmpEnd);
1076 return;
1077 }
1078
1079 LargeRep OldRep = std::move(*getLargeRep());
1080 getLargeRep()->~LargeRep();
1081 if (AtLeast <= InlineBuckets) {
1082 Small = true;
1083 } else {
1084 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
1085 }
1086
1087 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
1088
1089 // Free the old table.
1090 deallocate_buffer(OldRep.Buckets, sizeof(BucketT) * OldRep.NumBuckets,
1091 alignof(BucketT));
1092 }
1093
shrink_and_clear()1094 void shrink_and_clear() {
1095 unsigned OldSize = this->size();
1096 this->destroyAll();
1097
1098 // Reduce the number of buckets.
1099 unsigned NewNumBuckets = 0;
1100 if (OldSize) {
1101 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
1102 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
1103 NewNumBuckets = 64;
1104 }
1105 if ((Small && NewNumBuckets <= InlineBuckets) ||
1106 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
1107 this->BaseT::initEmpty();
1108 return;
1109 }
1110
1111 deallocateBuckets();
1112 init(NewNumBuckets);
1113 }
1114
1115 private:
getNumEntries()1116 unsigned getNumEntries() const {
1117 return NumEntries;
1118 }
1119
setNumEntries(unsigned Num)1120 void setNumEntries(unsigned Num) {
1121 // NumEntries is hardcoded to be 31 bits wide.
1122 assert(Num < (1U << 31) && "Cannot support more than 1<<31 entries");
1123 NumEntries = Num;
1124 }
1125
getNumTombstones()1126 unsigned getNumTombstones() const {
1127 return NumTombstones;
1128 }
1129
setNumTombstones(unsigned Num)1130 void setNumTombstones(unsigned Num) {
1131 NumTombstones = Num;
1132 }
1133
getInlineBuckets()1134 const BucketT *getInlineBuckets() const {
1135 assert(Small);
1136 // Note that this cast does not violate aliasing rules as we assert that
1137 // the memory's dynamic type is the small, inline bucket buffer, and the
1138 // 'storage' is a POD containing a char buffer.
1139 return reinterpret_cast<const BucketT *>(&storage);
1140 }
1141
getInlineBuckets()1142 BucketT *getInlineBuckets() {
1143 return const_cast<BucketT *>(
1144 const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
1145 }
1146
getLargeRep()1147 const LargeRep *getLargeRep() const {
1148 assert(!Small);
1149 // Note, same rule about aliasing as with getInlineBuckets.
1150 return reinterpret_cast<const LargeRep *>(&storage);
1151 }
1152
getLargeRep()1153 LargeRep *getLargeRep() {
1154 return const_cast<LargeRep *>(
1155 const_cast<const SmallDenseMap *>(this)->getLargeRep());
1156 }
1157
getBuckets()1158 const BucketT *getBuckets() const {
1159 return Small ? getInlineBuckets() : getLargeRep()->Buckets;
1160 }
1161
getBuckets()1162 BucketT *getBuckets() {
1163 return const_cast<BucketT *>(
1164 const_cast<const SmallDenseMap *>(this)->getBuckets());
1165 }
1166
getNumBuckets()1167 unsigned getNumBuckets() const {
1168 return Small ? InlineBuckets : getLargeRep()->NumBuckets;
1169 }
1170
deallocateBuckets()1171 void deallocateBuckets() {
1172 if (Small)
1173 return;
1174
1175 deallocate_buffer(getLargeRep()->Buckets,
1176 sizeof(BucketT) * getLargeRep()->NumBuckets,
1177 alignof(BucketT));
1178 getLargeRep()->~LargeRep();
1179 }
1180
allocateBuckets(unsigned Num)1181 LargeRep allocateBuckets(unsigned Num) {
1182 assert(Num > InlineBuckets && "Must allocate more buckets than are inline");
1183 LargeRep Rep = {static_cast<BucketT *>(allocate_buffer(
1184 sizeof(BucketT) * Num, alignof(BucketT))),
1185 Num};
1186 return Rep;
1187 }
1188 };
1189
1190 template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
1191 bool IsConst>
1192 class DenseMapIterator : DebugEpochBase::HandleBase {
1193 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
1194 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>;
1195
1196 public:
1197 using difference_type = ptrdiff_t;
1198 using value_type =
1199 typename std::conditional<IsConst, const Bucket, Bucket>::type;
1200 using pointer = value_type *;
1201 using reference = value_type &;
1202 using iterator_category = std::forward_iterator_tag;
1203
1204 private:
1205 pointer Ptr = nullptr;
1206 pointer End = nullptr;
1207
1208 public:
1209 DenseMapIterator() = default;
1210
1211 DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch,
1212 bool NoAdvance = false)
1213 : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) {
1214 assert(isHandleInSync() && "invalid construction!");
1215
1216 if (NoAdvance) return;
1217 if (shouldReverseIterate<KeyT>()) {
1218 RetreatPastEmptyBuckets();
1219 return;
1220 }
1221 AdvancePastEmptyBuckets();
1222 }
1223
1224 // Converting ctor from non-const iterators to const iterators. SFINAE'd out
1225 // for const iterator destinations so it doesn't end up as a user defined copy
1226 // constructor.
1227 template <bool IsConstSrc,
1228 typename = std::enable_if_t<!IsConstSrc && IsConst>>
DenseMapIterator(const DenseMapIterator<KeyT,ValueT,KeyInfoT,Bucket,IsConstSrc> & I)1229 DenseMapIterator(
1230 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I)
1231 : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {}
1232
1233 reference operator*() const {
1234 assert(isHandleInSync() && "invalid iterator access!");
1235 assert(Ptr != End && "dereferencing end() iterator");
1236 if (shouldReverseIterate<KeyT>())
1237 return Ptr[-1];
1238 return *Ptr;
1239 }
1240 pointer operator->() const {
1241 assert(isHandleInSync() && "invalid iterator access!");
1242 assert(Ptr != End && "dereferencing end() iterator");
1243 if (shouldReverseIterate<KeyT>())
1244 return &(Ptr[-1]);
1245 return Ptr;
1246 }
1247
1248 friend bool operator==(const DenseMapIterator &LHS,
1249 const DenseMapIterator &RHS) {
1250 assert((!LHS.Ptr || LHS.isHandleInSync()) && "handle not in sync!");
1251 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1252 assert(LHS.getEpochAddress() == RHS.getEpochAddress() &&
1253 "comparing incomparable iterators!");
1254 return LHS.Ptr == RHS.Ptr;
1255 }
1256
1257 friend bool operator!=(const DenseMapIterator &LHS,
1258 const DenseMapIterator &RHS) {
1259 return !(LHS == RHS);
1260 }
1261
1262 inline DenseMapIterator& operator++() { // Preincrement
1263 assert(isHandleInSync() && "invalid iterator access!");
1264 assert(Ptr != End && "incrementing end() iterator");
1265 if (shouldReverseIterate<KeyT>()) {
1266 --Ptr;
1267 RetreatPastEmptyBuckets();
1268 return *this;
1269 }
1270 ++Ptr;
1271 AdvancePastEmptyBuckets();
1272 return *this;
1273 }
1274 DenseMapIterator operator++(int) { // Postincrement
1275 assert(isHandleInSync() && "invalid iterator access!");
1276 DenseMapIterator tmp = *this; ++*this; return tmp;
1277 }
1278
1279 private:
AdvancePastEmptyBuckets()1280 void AdvancePastEmptyBuckets() {
1281 assert(Ptr <= End);
1282 const KeyT Empty = KeyInfoT::getEmptyKey();
1283 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1284
1285 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
1286 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
1287 ++Ptr;
1288 }
1289
RetreatPastEmptyBuckets()1290 void RetreatPastEmptyBuckets() {
1291 assert(Ptr >= End);
1292 const KeyT Empty = KeyInfoT::getEmptyKey();
1293 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1294
1295 while (Ptr != End && (KeyInfoT::isEqual(Ptr[-1].getFirst(), Empty) ||
1296 KeyInfoT::isEqual(Ptr[-1].getFirst(), Tombstone)))
1297 --Ptr;
1298 }
1299 };
1300
1301 template <typename KeyT, typename ValueT, typename KeyInfoT>
capacity_in_bytes(const DenseMap<KeyT,ValueT,KeyInfoT> & X)1302 inline size_t capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
1303 return X.getMemorySize();
1304 }
1305
1306 } // end namespace llvm
1307
1308 #endif // LLVM_ADT_DENSEMAP_H
1309