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1//===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the DenseMap class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_ADT_DENSEMAP_H
15#define LLVM_ADT_DENSEMAP_H
16
17#include "llvm/ADT/DenseMapInfo.h"
18#include "llvm/ADT/EpochTracker.h"
19#include "llvm/Support/AlignOf.h"
20#include "llvm/Support/Compiler.h"
21#include "llvm/Support/MathExtras.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 <iterator>
29#include <new>
30#include <type_traits>
31#include <utility>
32
33namespace llvm {
34
35namespace detail {
36
37// We extend a pair to allow users to override the bucket type with their own
38// implementation without requiring two members.
39template <typename KeyT, typename ValueT>
40struct DenseMapPair : public std::pair<KeyT, ValueT> {
41 KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
42 const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; }
43 ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; }
44 const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; }
45};
46
47} // end namespace detail
48
49template <
50 typename KeyT, typename ValueT, typename KeyInfoT = DenseMapInfo<KeyT>,
51 typename Bucket = detail::DenseMapPair<KeyT, ValueT>, bool IsConst = false>
52class DenseMapIterator;
53
54template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
55 typename BucketT>
56class DenseMapBase : public DebugEpochBase {
57 template <typename T>
58 using const_arg_type_t = typename const_pointer_or_const_ref<T>::type;
59
60public:
61 using size_type = unsigned;
62 using key_type = KeyT;
63 using mapped_type = ValueT;
64 using value_type = BucketT;
65
66 using iterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT>;
67 using const_iterator =
68 DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>;
69
70 inline iterator begin() {
71 // When the map is empty, avoid the overhead of advancing/retreating past
72 // empty buckets.
73 if (empty())
74 return end();
75 if (shouldReverseIterate<KeyT>())
76 return makeIterator(getBucketsEnd() - 1, getBuckets(), *this);
77 return makeIterator(getBuckets(), getBucketsEnd(), *this);
78 }
79 inline iterator end() {
80 return makeIterator(getBucketsEnd(), getBucketsEnd(), *this, true);
81 }
82 inline const_iterator begin() const {
83 if (empty())
84 return end();
85 if (shouldReverseIterate<KeyT>())
86 return makeConstIterator(getBucketsEnd() - 1, getBuckets(), *this);
87 return makeConstIterator(getBuckets(), getBucketsEnd(), *this);
88 }
89 inline const_iterator end() const {
90 return makeConstIterator(getBucketsEnd(), getBucketsEnd(), *this, true);
91 }
92
93 LLVM_NODISCARD bool empty() const {
94 return getNumEntries() == 0;
95 }
96 unsigned size() const { return getNumEntries(); }
97
98 /// Grow the densemap so that it can contain at least \p NumEntries items
99 /// before resizing again.
100 void reserve(size_type NumEntries) {
101 auto NumBuckets = getMinBucketToReserveForEntries(NumEntries);
102 incrementEpoch();
103 if (NumBuckets > getNumBuckets())
104 grow(NumBuckets);
105 }
106
107 void clear() {
108 incrementEpoch();
109 if (getNumEntries() == 0 && getNumTombstones() == 0) return;
110
111 // If the capacity of the array is huge, and the # elements used is small,
112 // shrink the array.
113 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) {
114 shrink_and_clear();
115 return;
116 }
117
118 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
119 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value) {
120 // Use a simpler loop when these are trivial types.
121 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P)
122 P->getFirst() = EmptyKey;
123 } else {
124 unsigned NumEntries = getNumEntries();
125 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
126 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
127 if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
128 P->getSecond().~ValueT();
129 --NumEntries;
130 }
131 P->getFirst() = EmptyKey;
132 }
133 }
134 assert(NumEntries == 0 && "Node count imbalance!");
135 }
136 setNumEntries(0);
137 setNumTombstones(0);
138 }
139
140 /// Return 1 if the specified key is in the map, 0 otherwise.
141 size_type count(const_arg_type_t<KeyT> Val) const {
142 const BucketT *TheBucket;
143 return LookupBucketFor(Val, TheBucket) ? 1 : 0;
144 }
145
146 iterator find(const_arg_type_t<KeyT> Val) {
147 BucketT *TheBucket;
148 if (LookupBucketFor(Val, TheBucket))
149 return makeIterator(TheBucket, getBucketsEnd(), *this, true);
150 return end();
151 }
152 const_iterator find(const_arg_type_t<KeyT> Val) const {
153 const BucketT *TheBucket;
154 if (LookupBucketFor(Val, TheBucket))
155 return makeConstIterator(TheBucket, getBucketsEnd(), *this, true);
156 return end();
157 }
158
159 /// Alternate version of find() which allows a different, and possibly
160 /// less expensive, key type.
161 /// The DenseMapInfo is responsible for supplying methods
162 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
163 /// type used.
164 template<class LookupKeyT>
165 iterator find_as(const LookupKeyT &Val) {
166 BucketT *TheBucket;
167 if (LookupBucketFor(Val, TheBucket))
168 return makeIterator(TheBucket, getBucketsEnd(), *this, true);
169 return end();
170 }
171 template<class LookupKeyT>
172 const_iterator find_as(const LookupKeyT &Val) const {
173 const BucketT *TheBucket;
174 if (LookupBucketFor(Val, TheBucket))
175 return makeConstIterator(TheBucket, getBucketsEnd(), *this, true);
176 return end();
177 }
178
179 /// lookup - Return the entry for the specified key, or a default
180 /// constructed value if no such entry exists.
181 ValueT lookup(const_arg_type_t<KeyT> Val) const {
182 const BucketT *TheBucket;
183 if (LookupBucketFor(Val, TheBucket))
184 return TheBucket->getSecond();
185 return ValueT();
186 }
187
188 // Inserts key,value pair into the map if the key isn't already in the map.
189 // If the key is already in the map, it returns false and doesn't update the
190 // value.
191 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
192 return try_emplace(KV.first, KV.second);
193 }
194
195 // Inserts key,value pair into the map if the key isn't already in the map.
196 // If the key is already in the map, it returns false and doesn't update the
197 // value.
198 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
199 return try_emplace(std::move(KV.first), std::move(KV.second));
200 }
201
202 // Inserts key,value pair into the map if the key isn't already in the map.
203 // The value is constructed in-place if the key is not in the map, otherwise
204 // it is not moved.
205 template <typename... Ts>
206 std::pair<iterator, bool> try_emplace(KeyT &&Key, Ts &&... Args) {
207 BucketT *TheBucket;
208 if (LookupBucketFor(Key, TheBucket))
209 return std::make_pair(
210 makeIterator(TheBucket, getBucketsEnd(), *this, true),
211 false); // Already in map.
212
213 // Otherwise, insert the new element.
214 TheBucket =
215 InsertIntoBucket(TheBucket, std::move(Key), std::forward<Ts>(Args)...);
216 return std::make_pair(
217 makeIterator(TheBucket, getBucketsEnd(), *this, true),
218 true);
219 }
220
221 // Inserts key,value pair into the map if the key isn't already in the map.
222 // The value is constructed in-place if the key is not in the map, otherwise
223 // it is not moved.
224 template <typename... Ts>
225 std::pair<iterator, bool> try_emplace(const KeyT &Key, Ts &&... Args) {
226 BucketT *TheBucket;
227 if (LookupBucketFor(Key, TheBucket))
228 return std::make_pair(
229 makeIterator(TheBucket, getBucketsEnd(), *this, true),
230 false); // Already in map.
231
232 // Otherwise, insert the new element.
233 TheBucket = InsertIntoBucket(TheBucket, Key, std::forward<Ts>(Args)...);
234 return std::make_pair(
235 makeIterator(TheBucket, getBucketsEnd(), *this, true),
236 true);
237 }
238
239 /// Alternate version of insert() which allows a different, and possibly
240 /// less expensive, key type.
241 /// The DenseMapInfo is responsible for supplying methods
242 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
243 /// type used.
244 template <typename LookupKeyT>
245 std::pair<iterator, bool> insert_as(std::pair<KeyT, ValueT> &&KV,
246 const LookupKeyT &Val) {
247 BucketT *TheBucket;
248 if (LookupBucketFor(Val, TheBucket))
249 return std::make_pair(
250 makeIterator(TheBucket, getBucketsEnd(), *this, true),
251 false); // Already in map.
252
253 // Otherwise, insert the new element.
254 TheBucket = InsertIntoBucketWithLookup(TheBucket, std::move(KV.first),
255 std::move(KV.second), Val);
256 return std::make_pair(
257 makeIterator(TheBucket, getBucketsEnd(), *this, true),
258 true);
259 }
260
261 /// insert - Range insertion of pairs.
262 template<typename InputIt>
263 void insert(InputIt I, InputIt E) {
264 for (; I != E; ++I)
265 insert(*I);
266 }
267
268 bool erase(const KeyT &Val) {
269 BucketT *TheBucket;
270 if (!LookupBucketFor(Val, TheBucket))
271 return false; // not in map.
272
273 TheBucket->getSecond().~ValueT();
274 TheBucket->getFirst() = getTombstoneKey();
275 decrementNumEntries();
276 incrementNumTombstones();
277 return true;
278 }
279 void erase(iterator I) {
280 BucketT *TheBucket = &*I;
281 TheBucket->getSecond().~ValueT();
282 TheBucket->getFirst() = getTombstoneKey();
283 decrementNumEntries();
284 incrementNumTombstones();
285 }
286
287 value_type& FindAndConstruct(const KeyT &Key) {
288 BucketT *TheBucket;
289 if (LookupBucketFor(Key, TheBucket))
290 return *TheBucket;
291
292 return *InsertIntoBucket(TheBucket, Key);
293 }
294
295 ValueT &operator[](const KeyT &Key) {
296 return FindAndConstruct(Key).second;
297 }
298
299 value_type& FindAndConstruct(KeyT &&Key) {
300 BucketT *TheBucket;
301 if (LookupBucketFor(Key, TheBucket))
302 return *TheBucket;
303
304 return *InsertIntoBucket(TheBucket, std::move(Key));
305 }
306
307 ValueT &operator[](KeyT &&Key) {
308 return FindAndConstruct(std::move(Key)).second;
309 }
310
311 /// isPointerIntoBucketsArray - Return true if the specified pointer points
312 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or
313 /// value in the DenseMap).
314 bool isPointerIntoBucketsArray(const void *Ptr) const {
315 return Ptr >= getBuckets() && Ptr < getBucketsEnd();
316 }
317
318 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
319 /// array. In conjunction with the previous method, this can be used to
320 /// determine whether an insertion caused the DenseMap to reallocate.
321 const void *getPointerIntoBucketsArray() const { return getBuckets(); }
322
323protected:
324 DenseMapBase() = default;
325
326 void destroyAll() {
327 if (getNumBuckets() == 0) // Nothing to do.
328 return;
329
330 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
331 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
332 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
333 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
334 P->getSecond().~ValueT();
335 P->getFirst().~KeyT();
336 }
337 }
338
339 void initEmpty() {
340 setNumEntries(0);
341 setNumTombstones(0);
342
343 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&
344 "# initial buckets must be a power of two!");
345 const KeyT EmptyKey = getEmptyKey();
346 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
347 ::new (&B->getFirst()) KeyT(EmptyKey);
348 }
349
350 /// Returns the number of buckets to allocate to ensure that the DenseMap can
351 /// accommodate \p NumEntries without need to grow().
352 unsigned getMinBucketToReserveForEntries(unsigned NumEntries) {
353 // Ensure that "NumEntries * 4 < NumBuckets * 3"
354 if (NumEntries == 0)
355 return 0;
356 // +1 is required because of the strict equality.
357 // For example if NumEntries is 48, we need to return 401.
358 return NextPowerOf2(NumEntries * 4 / 3 + 1);
359 }
360
361 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
362 initEmpty();
363
364 // Insert all the old elements.
365 const KeyT EmptyKey = getEmptyKey();
366 const KeyT TombstoneKey = getTombstoneKey();
367 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
368 if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) &&
369 !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) {
370 // Insert the key/value into the new table.
371 BucketT *DestBucket;
372 bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket);
373 (void)FoundVal; // silence warning.
374 assert(!FoundVal && "Key already in new map?");
375 DestBucket->getFirst() = std::move(B->getFirst());
376 ::new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
377 incrementNumEntries();
378
379 // Free the value.
380 B->getSecond().~ValueT();
381 }
382 B->getFirst().~KeyT();
383 }
384 }
385
386 template <typename OtherBaseT>
387 void copyFrom(
388 const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
389 assert(&other != this);
390 assert(getNumBuckets() == other.getNumBuckets());
391
392 setNumEntries(other.getNumEntries());
393 setNumTombstones(other.getNumTombstones());
394
395 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value)
396 memcpy(getBuckets(), other.getBuckets(),
397 getNumBuckets() * sizeof(BucketT));
398 else
399 for (size_t i = 0; i < getNumBuckets(); ++i) {
400 ::new (&getBuckets()[i].getFirst())
401 KeyT(other.getBuckets()[i].getFirst());
402 if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) &&
403 !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey()))
404 ::new (&getBuckets()[i].getSecond())
405 ValueT(other.getBuckets()[i].getSecond());
406 }
407 }
408
409 static unsigned getHashValue(const KeyT &Val) {
410 return KeyInfoT::getHashValue(Val);
411 }
412
413 template<typename LookupKeyT>
414 static unsigned getHashValue(const LookupKeyT &Val) {
415 return KeyInfoT::getHashValue(Val);
416 }
417
418 static const KeyT getEmptyKey() {
419 static_assert(std::is_base_of<DenseMapBase, DerivedT>::value,
420 "Must pass the derived type to this template!");
421 return KeyInfoT::getEmptyKey();
422 }
423
424 static const KeyT getTombstoneKey() {
425 return KeyInfoT::getTombstoneKey();
426 }
427
428private:
429 iterator makeIterator(BucketT *P, BucketT *E,
430 DebugEpochBase &Epoch,
431 bool NoAdvance=false) {
432 if (shouldReverseIterate<KeyT>()) {
433 BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1;
434 return iterator(B, E, Epoch, NoAdvance);
435 }
436 return iterator(P, E, Epoch, NoAdvance);
437 }
438
439 const_iterator makeConstIterator(const BucketT *P, const BucketT *E,
440 const DebugEpochBase &Epoch,
441 const bool NoAdvance=false) const {
442 if (shouldReverseIterate<KeyT>()) {
443 const BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1;
444 return const_iterator(B, E, Epoch, NoAdvance);
445 }
446 return const_iterator(P, E, Epoch, NoAdvance);
447 }
448
449 unsigned getNumEntries() const {
450 return static_cast<const DerivedT *>(this)->getNumEntries();
451 }
452
453 void setNumEntries(unsigned Num) {
454 static_cast<DerivedT *>(this)->setNumEntries(Num);
455 }
456
457 void incrementNumEntries() {
458 setNumEntries(getNumEntries() + 1);
459 }
460
461 void decrementNumEntries() {
462 setNumEntries(getNumEntries() - 1);
463 }
464
465 unsigned getNumTombstones() const {
466 return static_cast<const DerivedT *>(this)->getNumTombstones();
467 }
468
469 void setNumTombstones(unsigned Num) {
470 static_cast<DerivedT *>(this)->setNumTombstones(Num);
471 }
472
473 void incrementNumTombstones() {
474 setNumTombstones(getNumTombstones() + 1);
475 }
476
477 void decrementNumTombstones() {
478 setNumTombstones(getNumTombstones() - 1);
479 }
480
481 const BucketT *getBuckets() const {
482 return static_cast<const DerivedT *>(this)->getBuckets();
483 }
484
485 BucketT *getBuckets() {
486 return static_cast<DerivedT *>(this)->getBuckets();
487 }
488
489 unsigned getNumBuckets() const {
490 return static_cast<const DerivedT *>(this)->getNumBuckets();
491 }
492
493 BucketT *getBucketsEnd() {
494 return getBuckets() + getNumBuckets();
495 }
496
497 const BucketT *getBucketsEnd() const {
498 return getBuckets() + getNumBuckets();
499 }
500
501 void grow(unsigned AtLeast) {
502 static_cast<DerivedT *>(this)->grow(AtLeast);
503 }
504
505 void shrink_and_clear() {
506 static_cast<DerivedT *>(this)->shrink_and_clear();
507 }
508
509 template <typename KeyArg, typename... ValueArgs>
510 BucketT *InsertIntoBucket(BucketT *TheBucket, KeyArg &&Key,
511 ValueArgs &&... Values) {
512 TheBucket = InsertIntoBucketImpl(Key, Key, TheBucket);
513
514 TheBucket->getFirst() = std::forward<KeyArg>(Key);
515 ::new (&TheBucket->getSecond()) ValueT(std::forward<ValueArgs>(Values)...);
516 return TheBucket;
517 }
518
519 template <typename LookupKeyT>
520 BucketT *InsertIntoBucketWithLookup(BucketT *TheBucket, KeyT &&Key,
521 ValueT &&Value, LookupKeyT &Lookup) {
522 TheBucket = InsertIntoBucketImpl(Key, Lookup, TheBucket);
523
524 TheBucket->getFirst() = std::move(Key);
525 ::new (&TheBucket->getSecond()) ValueT(std::move(Value));
526 return TheBucket;
527 }
528
529 template <typename LookupKeyT>
530 BucketT *InsertIntoBucketImpl(const KeyT &Key, const LookupKeyT &Lookup,
531 BucketT *TheBucket) {
532 incrementEpoch();
533
534 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of
535 // the buckets are empty (meaning that many are filled with tombstones),
536 // grow the table.
537 //
538 // The later case is tricky. For example, if we had one empty bucket with
539 // tons of tombstones, failing lookups (e.g. for insertion) would have to
540 // probe almost the entire table until it found the empty bucket. If the
541 // table completely filled with tombstones, no lookup would ever succeed,
542 // causing infinite loops in lookup.
543 unsigned NewNumEntries = getNumEntries() + 1;
544 unsigned NumBuckets = getNumBuckets();
545 if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)) {
546 this->grow(NumBuckets * 2);
547 LookupBucketFor(Lookup, TheBucket);
548 NumBuckets = getNumBuckets();
549 } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=
550 NumBuckets/8)) {
551 this->grow(NumBuckets);
552 LookupBucketFor(Lookup, TheBucket);
553 }
554 assert(TheBucket);
555
556 // Only update the state after we've grown our bucket space appropriately
557 // so that when growing buckets we have self-consistent entry count.
558 incrementNumEntries();
559
560 // If we are writing over a tombstone, remember this.
561 const KeyT EmptyKey = getEmptyKey();
562 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
563 decrementNumTombstones();
564
565 return TheBucket;
566 }
567
568 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
569 /// FoundBucket. If the bucket contains the key and a value, this returns
570 /// true, otherwise it returns a bucket with an empty marker or tombstone and
571 /// returns false.
572 template<typename LookupKeyT>
573 bool LookupBucketFor(const LookupKeyT &Val,
574 const BucketT *&FoundBucket) const {
575 const BucketT *BucketsPtr = getBuckets();
576 const unsigned NumBuckets = getNumBuckets();
577
578 if (NumBuckets == 0) {
579 FoundBucket = nullptr;
580 return false;
581 }
582
583 // FoundTombstone - Keep track of whether we find a tombstone while probing.
584 const BucketT *FoundTombstone = nullptr;
585 const KeyT EmptyKey = getEmptyKey();
586 const KeyT TombstoneKey = getTombstoneKey();
587 assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
588 !KeyInfoT::isEqual(Val, TombstoneKey) &&
589 "Empty/Tombstone value shouldn't be inserted into map!");
590
591 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
592 unsigned ProbeAmt = 1;
593 while (true) {
594 const BucketT *ThisBucket = BucketsPtr + BucketNo;
595 // Found Val's bucket? If so, return it.
596 if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))) {
597 FoundBucket = ThisBucket;
598 return true;
599 }
600
601 // If we found an empty bucket, the key doesn't exist in the set.
602 // Insert it and return the default value.
603 if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))) {
604 // If we've already seen a tombstone while probing, fill it in instead
605 // of the empty bucket we eventually probed to.
606 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
607 return false;
608 }
609
610 // If this is a tombstone, remember it. If Val ends up not in the map, we
611 // prefer to return it than something that would require more probing.
612 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
613 !FoundTombstone)
614 FoundTombstone = ThisBucket; // Remember the first tombstone found.
615
616 // Otherwise, it's a hash collision or a tombstone, continue quadratic
617 // probing.
618 BucketNo += ProbeAmt++;
619 BucketNo &= (NumBuckets-1);
620 }
621 }
622
623 template <typename LookupKeyT>
624 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
625 const BucketT *ConstFoundBucket;
626 bool Result = const_cast<const DenseMapBase *>(this)
627 ->LookupBucketFor(Val, ConstFoundBucket);
628 FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
629 return Result;
630 }
631
632public:
633 /// Return the approximate size (in bytes) of the actual map.
634 /// This is just the raw memory used by DenseMap.
635 /// If entries are pointers to objects, the size of the referenced objects
636 /// are not included.
637 size_t getMemorySize() const {
638 return getNumBuckets() * sizeof(BucketT);
639 }
640};
641
642template <typename KeyT, typename ValueT,
643 typename KeyInfoT = DenseMapInfo<KeyT>,
644 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
645class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
646 KeyT, ValueT, KeyInfoT, BucketT> {
647 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
648
649 // Lift some types from the dependent base class into this class for
650 // simplicity of referring to them.
651 using BaseT = DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
652
653 BucketT *Buckets;
654 unsigned NumEntries;
655 unsigned NumTombstones;
656 unsigned NumBuckets;
657
658public:
659 /// Create a DenseMap wth an optional \p InitialReserve that guarantee that
660 /// this number of elements can be inserted in the map without grow()
661 explicit DenseMap(unsigned InitialReserve = 0) { init(InitialReserve); }
662
663 DenseMap(const DenseMap &other) : BaseT() {
664 init(0);
665 copyFrom(other);
666 }
667
668 DenseMap(DenseMap &&other) : BaseT() {
669 init(0);
670 swap(other);
671 }
672
673 template<typename InputIt>
674 DenseMap(const InputIt &I, const InputIt &E) {
675 init(std::distance(I, E));
676 this->insert(I, E);
677 }
678
679 ~DenseMap() {
680 this->destroyAll();
681 operator delete(Buckets);
682 }
683
684 void swap(DenseMap& RHS) {
685 this->incrementEpoch();
686 RHS.incrementEpoch();
687 std::swap(Buckets, RHS.Buckets);
688 std::swap(NumEntries, RHS.NumEntries);
689 std::swap(NumTombstones, RHS.NumTombstones);
690 std::swap(NumBuckets, RHS.NumBuckets);
691 }
692
693 DenseMap& operator=(const DenseMap& other) {
694 if (&other != this)
695 copyFrom(other);
696 return *this;
697 }
698
699 DenseMap& operator=(DenseMap &&other) {
700 this->destroyAll();
701 operator delete(Buckets);
702 init(0);
703 swap(other);
704 return *this;
705 }
706
707 void copyFrom(const DenseMap& other) {
708 this->destroyAll();
709 operator delete(Buckets);
710 if (allocateBuckets(other.NumBuckets)) {
711 this->BaseT::copyFrom(other);
712 } else {
713 NumEntries = 0;
714 NumTombstones = 0;
715 }
716 }
717
718 void init(unsigned InitNumEntries) {
719 auto InitBuckets = BaseT::getMinBucketToReserveForEntries(InitNumEntries);
720 if (allocateBuckets(InitBuckets)) {
721 this->BaseT::initEmpty();
722 } else {
723 NumEntries = 0;
724 NumTombstones = 0;
725 }
726 }
727
728 void grow(unsigned AtLeast) {
729 unsigned OldNumBuckets = NumBuckets;
730 BucketT *OldBuckets = Buckets;
731
732 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
733 assert(Buckets);
734 if (!OldBuckets) {
735 this->BaseT::initEmpty();
736 return;
737 }
738
739 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
740
741 // Free the old table.
742 operator delete(OldBuckets);
743 }
744
745 void shrink_and_clear() {
746 unsigned OldNumEntries = NumEntries;
747 this->destroyAll();
748
749 // Reduce the number of buckets.
750 unsigned NewNumBuckets = 0;
751 if (OldNumEntries)
752 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
753 if (NewNumBuckets == NumBuckets) {
754 this->BaseT::initEmpty();
755 return;
756 }
757
758 operator delete(Buckets);
759 init(NewNumBuckets);
760 }
761
762private:
763 unsigned getNumEntries() const {
764 return NumEntries;
765 }
766
767 void setNumEntries(unsigned Num) {
768 NumEntries = Num;
769 }
770
771 unsigned getNumTombstones() const {
772 return NumTombstones;
773 }
774
775 void setNumTombstones(unsigned Num) {
776 NumTombstones = Num;
777 }
778
779 BucketT *getBuckets() const {
780 return Buckets;
781 }
782
783 unsigned getNumBuckets() const {
784 return NumBuckets;
785 }
786
787 bool allocateBuckets(unsigned Num) {
788 NumBuckets = Num;
789 if (NumBuckets == 0) {
790 Buckets = nullptr;
791 return false;
792 }
793
794 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets));
795 return true;
796 }
797};
798
799template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
800 typename KeyInfoT = DenseMapInfo<KeyT>,
801 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
802class SmallDenseMap
803 : public DenseMapBase<
804 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
805 ValueT, KeyInfoT, BucketT> {
806 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
807
808 // Lift some types from the dependent base class into this class for
809 // simplicity of referring to them.
810 using BaseT = DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
811
812 static_assert(isPowerOf2_64(InlineBuckets),
813 "InlineBuckets must be a power of 2.");
814
815 unsigned Small : 1;
816 unsigned NumEntries : 31;
817 unsigned NumTombstones;
818
819 struct LargeRep {
820 BucketT *Buckets;
821 unsigned NumBuckets;
822 };
823
824 /// A "union" of an inline bucket array and the struct representing
825 /// a large bucket. This union will be discriminated by the 'Small' bit.
826 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
827
828public:
829 explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
830 init(NumInitBuckets);
831 }
832
833 SmallDenseMap(const SmallDenseMap &other) : BaseT() {
834 init(0);
835 copyFrom(other);
836 }
837
838 SmallDenseMap(SmallDenseMap &&other) : BaseT() {
839 init(0);
840 swap(other);
841 }
842
843 template<typename InputIt>
844 SmallDenseMap(const InputIt &I, const InputIt &E) {
845 init(NextPowerOf2(std::distance(I, E)));
846 this->insert(I, E);
847 }
848
849 ~SmallDenseMap() {
850 this->destroyAll();
851 deallocateBuckets();
852 }
853
854 void swap(SmallDenseMap& RHS) {
855 unsigned TmpNumEntries = RHS.NumEntries;
856 RHS.NumEntries = NumEntries;
857 NumEntries = TmpNumEntries;
858 std::swap(NumTombstones, RHS.NumTombstones);
859
860 const KeyT EmptyKey = this->getEmptyKey();
861 const KeyT TombstoneKey = this->getTombstoneKey();
862 if (Small && RHS.Small) {
863 // If we're swapping inline bucket arrays, we have to cope with some of
864 // the tricky bits of DenseMap's storage system: the buckets are not
865 // fully initialized. Thus we swap every key, but we may have
866 // a one-directional move of the value.
867 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
868 BucketT *LHSB = &getInlineBuckets()[i],
869 *RHSB = &RHS.getInlineBuckets()[i];
870 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
871 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
872 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
873 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
874 if (hasLHSValue && hasRHSValue) {
875 // Swap together if we can...
876 std::swap(*LHSB, *RHSB);
877 continue;
878 }
879 // Swap separately and handle any assymetry.
880 std::swap(LHSB->getFirst(), RHSB->getFirst());
881 if (hasLHSValue) {
882 ::new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
883 LHSB->getSecond().~ValueT();
884 } else if (hasRHSValue) {
885 ::new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
886 RHSB->getSecond().~ValueT();
887 }
888 }
889 return;
890 }
891 if (!Small && !RHS.Small) {
892 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
893 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
894 return;
895 }
896
897 SmallDenseMap &SmallSide = Small ? *this : RHS;
898 SmallDenseMap &LargeSide = Small ? RHS : *this;
899
900 // First stash the large side's rep and move the small side across.
901 LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
902 LargeSide.getLargeRep()->~LargeRep();
903 LargeSide.Small = true;
904 // This is similar to the standard move-from-old-buckets, but the bucket
905 // count hasn't actually rotated in this case. So we have to carefully
906 // move construct the keys and values into their new locations, but there
907 // is no need to re-hash things.
908 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
909 BucketT *NewB = &LargeSide.getInlineBuckets()[i],
910 *OldB = &SmallSide.getInlineBuckets()[i];
911 ::new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
912 OldB->getFirst().~KeyT();
913 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
914 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
915 ::new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
916 OldB->getSecond().~ValueT();
917 }
918 }
919
920 // The hard part of moving the small buckets across is done, just move
921 // the TmpRep into its new home.
922 SmallSide.Small = false;
923 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
924 }
925
926 SmallDenseMap& operator=(const SmallDenseMap& other) {
927 if (&other != this)
928 copyFrom(other);
929 return *this;
930 }
931
932 SmallDenseMap& operator=(SmallDenseMap &&other) {
933 this->destroyAll();
934 deallocateBuckets();
935 init(0);
936 swap(other);
937 return *this;
938 }
939
940 void copyFrom(const SmallDenseMap& other) {
941 this->destroyAll();
942 deallocateBuckets();
943 Small = true;
944 if (other.getNumBuckets() > InlineBuckets) {
945 Small = false;
946 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
947 }
948 this->BaseT::copyFrom(other);
949 }
950
951 void init(unsigned InitBuckets) {
952 Small = true;
953 if (InitBuckets > InlineBuckets) {
954 Small = false;
955 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
956 }
957 this->BaseT::initEmpty();
958 }
959
960 void grow(unsigned AtLeast) {
961 if (AtLeast >= InlineBuckets)
962 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
963
964 if (Small) {
965 if (AtLeast < InlineBuckets)
966 return; // Nothing to do.
967
968 // First move the inline buckets into a temporary storage.
969 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
970 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer);
971 BucketT *TmpEnd = TmpBegin;
972
973 // Loop over the buckets, moving non-empty, non-tombstones into the
974 // temporary storage. Have the loop move the TmpEnd forward as it goes.
975 const KeyT EmptyKey = this->getEmptyKey();
976 const KeyT TombstoneKey = this->getTombstoneKey();
977 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
978 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
979 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
980 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
981 "Too many inline buckets!");
982 ::new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
983 ::new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
984 ++TmpEnd;
985 P->getSecond().~ValueT();
986 }
987 P->getFirst().~KeyT();
988 }
989
990 // Now make this map use the large rep, and move all the entries back
991 // into it.
992 Small = false;
993 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
994 this->moveFromOldBuckets(TmpBegin, TmpEnd);
995 return;
996 }
997
998 LargeRep OldRep = std::move(*getLargeRep());
999 getLargeRep()->~LargeRep();
1000 if (AtLeast <= InlineBuckets) {
1001 Small = true;
1002 } else {
1003 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
1004 }
1005
1006 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
1007
1008 // Free the old table.
1009 operator delete(OldRep.Buckets);
1010 }
1011
1012 void shrink_and_clear() {
1013 unsigned OldSize = this->size();
1014 this->destroyAll();
1015
1016 // Reduce the number of buckets.
1017 unsigned NewNumBuckets = 0;
1018 if (OldSize) {
1019 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
1020 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
1021 NewNumBuckets = 64;
1022 }
1023 if ((Small && NewNumBuckets <= InlineBuckets) ||
1024 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
1025 this->BaseT::initEmpty();
1026 return;
1027 }
1028
1029 deallocateBuckets();
1030 init(NewNumBuckets);
1031 }
1032
1033private:
1034 unsigned getNumEntries() const {
1035 return NumEntries;
1036 }
1037
1038 void setNumEntries(unsigned Num) {
1039 // NumEntries is hardcoded to be 31 bits wide.
1040 assert(Num < (1U << 31) && "Cannot support more than 1<<31 entries");
1041 NumEntries = Num;
1042 }
1043
1044 unsigned getNumTombstones() const {
1045 return NumTombstones;
1046 }
1047
1048 void setNumTombstones(unsigned Num) {
1049 NumTombstones = Num;
1050 }
1051
1052 const BucketT *getInlineBuckets() const {
1053 assert(Small);
1054 // Note that this cast does not violate aliasing rules as we assert that
1055 // the memory's dynamic type is the small, inline bucket buffer, and the
1056 // 'storage.buffer' static type is 'char *'.
1057 return reinterpret_cast<const BucketT *>(storage.buffer);
1058 }
1059
1060 BucketT *getInlineBuckets() {
1061 return const_cast<BucketT *>(
1062 const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
1063 }
1064
1065 const LargeRep *getLargeRep() const {
1066 assert(!Small);
1067 // Note, same rule about aliasing as with getInlineBuckets.
1068 return reinterpret_cast<const LargeRep *>(storage.buffer);
1069 }
1070
1071 LargeRep *getLargeRep() {
1072 return const_cast<LargeRep *>(
1073 const_cast<const SmallDenseMap *>(this)->getLargeRep());
1074 }
1075
1076 const BucketT *getBuckets() const {
1077 return Small ? getInlineBuckets() : getLargeRep()->Buckets;
1078 }
1079
1080 BucketT *getBuckets() {
1081 return const_cast<BucketT *>(
1082 const_cast<const SmallDenseMap *>(this)->getBuckets());
1083 }
1084
1085 unsigned getNumBuckets() const {
1086 return Small ? InlineBuckets : getLargeRep()->NumBuckets;
1087 }
1088
1089 void deallocateBuckets() {
1090 if (Small)
1091 return;
1092
1093 operator delete(getLargeRep()->Buckets);
1094 getLargeRep()->~LargeRep();
1095 }
1096
1097 LargeRep allocateBuckets(unsigned Num) {
1098 assert(Num > InlineBuckets && "Must allocate more buckets than are inline");
1099 LargeRep Rep = {
1100 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num
1101 };
1102 return Rep;
1103 }
1104};
1105
1106template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
1107 bool IsConst>
1108class DenseMapIterator : DebugEpochBase::HandleBase {
1109 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
1110 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>;
1111
1112 using ConstIterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
1113
1114public:
1115 using difference_type = ptrdiff_t;
1116 using value_type =
1117 typename std::conditional<IsConst, const Bucket, Bucket>::type;
1118 using pointer = value_type *;
1119 using reference = value_type &;
1120 using iterator_category = std::forward_iterator_tag;
1121
1122private:
1123 pointer Ptr = nullptr;
1124 pointer End = nullptr;
1125
1126public:
1127 DenseMapIterator() = default;
1128
1129 DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch,
1130 bool NoAdvance = false)
1131 : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) {
1132 assert(isHandleInSync() && "invalid construction!");
1133
1134 if (NoAdvance) return;
1135 if (shouldReverseIterate<KeyT>()) {
1136 RetreatPastEmptyBuckets();
1137 return;
1138 }
1139 AdvancePastEmptyBuckets();
1140 }
1141
1142 // Converting ctor from non-const iterators to const iterators. SFINAE'd out
1143 // for const iterator destinations so it doesn't end up as a user defined copy
1144 // constructor.
1145 template <bool IsConstSrc,
1146 typename = typename std::enable_if<!IsConstSrc && IsConst>::type>
1147 DenseMapIterator(
1148 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I)
1149 : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {}
1150
1151 reference operator*() const {
1152 assert(isHandleInSync() && "invalid iterator access!");
1153 if (shouldReverseIterate<KeyT>())
1154 return Ptr[-1];
1155 return *Ptr;
1156 }
1157 pointer operator->() const {
1158 assert(isHandleInSync() && "invalid iterator access!");
1159 if (shouldReverseIterate<KeyT>())
1160 return &(Ptr[-1]);
1161 return Ptr;
1162 }
1163
1164 bool operator==(const ConstIterator &RHS) const {
1165 assert((!Ptr || isHandleInSync()) && "handle not in sync!");
1166 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1167 assert(getEpochAddress() == RHS.getEpochAddress() &&
1168 "comparing incomparable iterators!");
1169 return Ptr == RHS.Ptr;
1170 }
1171 bool operator!=(const ConstIterator &RHS) const {
1172 assert((!Ptr || isHandleInSync()) && "handle not in sync!");
1173 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1174 assert(getEpochAddress() == RHS.getEpochAddress() &&
1175 "comparing incomparable iterators!");
1176 return Ptr != RHS.Ptr;
1177 }
1178
1179 inline DenseMapIterator& operator++() { // Preincrement
1180 assert(isHandleInSync() && "invalid iterator access!");
1181 if (shouldReverseIterate<KeyT>()) {
1182 --Ptr;
1183 RetreatPastEmptyBuckets();
1184 return *this;
1185 }
1186 ++Ptr;
1187 AdvancePastEmptyBuckets();
1188 return *this;
1189 }
1190 DenseMapIterator operator++(int) { // Postincrement
1191 assert(isHandleInSync() && "invalid iterator access!");
1192 DenseMapIterator tmp = *this; ++*this; return tmp;
1193 }
1194
1195private:
1196 void AdvancePastEmptyBuckets() {
1197 assert(Ptr <= End);
1198 const KeyT Empty = KeyInfoT::getEmptyKey();
1199 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1200
1201 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
1202 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
1203 ++Ptr;
1204 }
1205
1206 void RetreatPastEmptyBuckets() {
1207 assert(Ptr >= End);
1208 const KeyT Empty = KeyInfoT::getEmptyKey();
1209 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1210
1211 while (Ptr != End && (KeyInfoT::isEqual(Ptr[-1].getFirst(), Empty) ||
1212 KeyInfoT::isEqual(Ptr[-1].getFirst(), Tombstone)))
1213 --Ptr;
1214 }
1215};
1216
1217template <typename KeyT, typename ValueT, typename KeyInfoT>
1218inline size_t capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
1219 return X.getMemorySize();
1220}
1221
1222} // end namespace llvm
1223
1224#endif // LLVM_ADT_DENSEMAP_H
1225

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