1 //===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the DenseMap class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ADT_DENSEMAP_H
15 #define LLVM_ADT_DENSEMAP_H
17 #include "llvm/ADT/DenseMapInfo.h"
18 #include "llvm/Support/AlignOf.h"
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/MathExtras.h"
21 #include "llvm/Support/PointerLikeTypeTraits.h"
22 #include "llvm/Support/type_traits.h"
35 // We extend a pair to allow users to override the bucket type with their own
36 // implementation without requiring two members.
37 template <typename KeyT, typename ValueT>
38 struct DenseMapPair : public std::pair<KeyT, ValueT> {
39 KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
40 const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; }
41 ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; }
42 const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; }
47 typename KeyT, typename ValueT, typename KeyInfoT = DenseMapInfo<KeyT>,
48 typename Bucket = detail::DenseMapPair<KeyT, ValueT>, bool IsConst = false>
49 class DenseMapIterator;
51 template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
55 typedef unsigned size_type;
56 typedef KeyT key_type;
57 typedef ValueT mapped_type;
58 typedef BucketT value_type;
60 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT> iterator;
61 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>
63 inline iterator begin() {
64 // When the map is empty, avoid the overhead of AdvancePastEmptyBuckets().
65 return empty() ? end() : iterator(getBuckets(), getBucketsEnd());
67 inline iterator end() {
68 return iterator(getBucketsEnd(), getBucketsEnd(), true);
70 inline const_iterator begin() const {
71 return empty() ? end() : const_iterator(getBuckets(), getBucketsEnd());
73 inline const_iterator end() const {
74 return const_iterator(getBucketsEnd(), getBucketsEnd(), true);
77 bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const {
78 return getNumEntries() == 0;
80 unsigned size() const { return getNumEntries(); }
82 /// Grow the densemap so that it has at least Size buckets. Does not shrink
83 void resize(size_type Size) {
84 if (Size > getNumBuckets())
89 if (getNumEntries() == 0 && getNumTombstones() == 0) return;
91 // If the capacity of the array is huge, and the # elements used is small,
93 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) {
98 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
99 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
100 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
101 if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
102 P->getSecond().~ValueT();
103 decrementNumEntries();
105 P->getFirst() = EmptyKey;
108 assert(getNumEntries() == 0 && "Node count imbalance!");
112 /// Return 1 if the specified key is in the map, 0 otherwise.
113 size_type count(const KeyT &Val) const {
114 const BucketT *TheBucket;
115 return LookupBucketFor(Val, TheBucket) ? 1 : 0;
118 iterator find(const KeyT &Val) {
120 if (LookupBucketFor(Val, TheBucket))
121 return iterator(TheBucket, getBucketsEnd(), true);
124 const_iterator find(const KeyT &Val) const {
125 const BucketT *TheBucket;
126 if (LookupBucketFor(Val, TheBucket))
127 return const_iterator(TheBucket, getBucketsEnd(), true);
131 /// Alternate version of find() which allows a different, and possibly
132 /// less expensive, key type.
133 /// The DenseMapInfo is responsible for supplying methods
134 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
136 template<class LookupKeyT>
137 iterator find_as(const LookupKeyT &Val) {
139 if (LookupBucketFor(Val, TheBucket))
140 return iterator(TheBucket, getBucketsEnd(), true);
143 template<class LookupKeyT>
144 const_iterator find_as(const LookupKeyT &Val) const {
145 const BucketT *TheBucket;
146 if (LookupBucketFor(Val, TheBucket))
147 return const_iterator(TheBucket, getBucketsEnd(), true);
151 /// lookup - Return the entry for the specified key, or a default
152 /// constructed value if no such entry exists.
153 ValueT lookup(const KeyT &Val) const {
154 const BucketT *TheBucket;
155 if (LookupBucketFor(Val, TheBucket))
156 return TheBucket->getSecond();
160 // Inserts key,value pair into the map if the key isn't already in the map.
161 // If the key is already in the map, it returns false and doesn't update the
163 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
165 if (LookupBucketFor(KV.first, TheBucket))
166 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true),
167 false); // Already in map.
169 // Otherwise, insert the new element.
170 TheBucket = InsertIntoBucket(KV.first, KV.second, TheBucket);
171 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true);
174 // Inserts key,value pair into the map if the key isn't already in the map.
175 // If the key is already in the map, it returns false and doesn't update the
177 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
179 if (LookupBucketFor(KV.first, TheBucket))
180 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true),
181 false); // Already in map.
183 // Otherwise, insert the new element.
184 TheBucket = InsertIntoBucket(std::move(KV.first),
185 std::move(KV.second),
187 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true);
190 /// insert - Range insertion of pairs.
191 template<typename InputIt>
192 void insert(InputIt I, InputIt E) {
198 bool erase(const KeyT &Val) {
200 if (!LookupBucketFor(Val, TheBucket))
201 return false; // not in map.
203 TheBucket->getSecond().~ValueT();
204 TheBucket->getFirst() = getTombstoneKey();
205 decrementNumEntries();
206 incrementNumTombstones();
209 void erase(iterator I) {
210 BucketT *TheBucket = &*I;
211 TheBucket->getSecond().~ValueT();
212 TheBucket->getFirst() = getTombstoneKey();
213 decrementNumEntries();
214 incrementNumTombstones();
217 value_type& FindAndConstruct(const KeyT &Key) {
219 if (LookupBucketFor(Key, TheBucket))
222 return *InsertIntoBucket(Key, ValueT(), TheBucket);
225 ValueT &operator[](const KeyT &Key) {
226 return FindAndConstruct(Key).second;
229 value_type& FindAndConstruct(KeyT &&Key) {
231 if (LookupBucketFor(Key, TheBucket))
234 return *InsertIntoBucket(std::move(Key), ValueT(), TheBucket);
237 ValueT &operator[](KeyT &&Key) {
238 return FindAndConstruct(std::move(Key)).second;
241 /// isPointerIntoBucketsArray - Return true if the specified pointer points
242 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or
243 /// value in the DenseMap).
244 bool isPointerIntoBucketsArray(const void *Ptr) const {
245 return Ptr >= getBuckets() && Ptr < getBucketsEnd();
248 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
249 /// array. In conjunction with the previous method, this can be used to
250 /// determine whether an insertion caused the DenseMap to reallocate.
251 const void *getPointerIntoBucketsArray() const { return getBuckets(); }
257 if (getNumBuckets() == 0) // Nothing to do.
260 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
261 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
262 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
263 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
264 P->getSecond().~ValueT();
265 P->getFirst().~KeyT();
269 memset((void*)getBuckets(), 0x5a, sizeof(BucketT)*getNumBuckets());
277 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&
278 "# initial buckets must be a power of two!");
279 const KeyT EmptyKey = getEmptyKey();
280 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
281 new (&B->getFirst()) KeyT(EmptyKey);
284 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
287 // Insert all the old elements.
288 const KeyT EmptyKey = getEmptyKey();
289 const KeyT TombstoneKey = getTombstoneKey();
290 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
291 if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) &&
292 !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) {
293 // Insert the key/value into the new table.
295 bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket);
296 (void)FoundVal; // silence warning.
297 assert(!FoundVal && "Key already in new map?");
298 DestBucket->getFirst() = std::move(B->getFirst());
299 new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
300 incrementNumEntries();
303 B->getSecond().~ValueT();
305 B->getFirst().~KeyT();
309 if (OldBucketsBegin != OldBucketsEnd)
310 memset((void*)OldBucketsBegin, 0x5a,
311 sizeof(BucketT) * (OldBucketsEnd - OldBucketsBegin));
315 template <typename OtherBaseT>
317 const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
318 assert(&other != this);
319 assert(getNumBuckets() == other.getNumBuckets());
321 setNumEntries(other.getNumEntries());
322 setNumTombstones(other.getNumTombstones());
324 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value)
325 memcpy(getBuckets(), other.getBuckets(),
326 getNumBuckets() * sizeof(BucketT));
328 for (size_t i = 0; i < getNumBuckets(); ++i) {
329 new (&getBuckets()[i].getFirst())
330 KeyT(other.getBuckets()[i].getFirst());
331 if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) &&
332 !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey()))
333 new (&getBuckets()[i].getSecond())
334 ValueT(other.getBuckets()[i].getSecond());
338 void swap(DenseMapBase& RHS) {
339 std::swap(getNumEntries(), RHS.getNumEntries());
340 std::swap(getNumTombstones(), RHS.getNumTombstones());
343 static unsigned getHashValue(const KeyT &Val) {
344 return KeyInfoT::getHashValue(Val);
346 template<typename LookupKeyT>
347 static unsigned getHashValue(const LookupKeyT &Val) {
348 return KeyInfoT::getHashValue(Val);
350 static const KeyT getEmptyKey() {
351 return KeyInfoT::getEmptyKey();
353 static const KeyT getTombstoneKey() {
354 return KeyInfoT::getTombstoneKey();
358 unsigned getNumEntries() const {
359 return static_cast<const DerivedT *>(this)->getNumEntries();
361 void setNumEntries(unsigned Num) {
362 static_cast<DerivedT *>(this)->setNumEntries(Num);
364 void incrementNumEntries() {
365 setNumEntries(getNumEntries() + 1);
367 void decrementNumEntries() {
368 setNumEntries(getNumEntries() - 1);
370 unsigned getNumTombstones() const {
371 return static_cast<const DerivedT *>(this)->getNumTombstones();
373 void setNumTombstones(unsigned Num) {
374 static_cast<DerivedT *>(this)->setNumTombstones(Num);
376 void incrementNumTombstones() {
377 setNumTombstones(getNumTombstones() + 1);
379 void decrementNumTombstones() {
380 setNumTombstones(getNumTombstones() - 1);
382 const BucketT *getBuckets() const {
383 return static_cast<const DerivedT *>(this)->getBuckets();
385 BucketT *getBuckets() {
386 return static_cast<DerivedT *>(this)->getBuckets();
388 unsigned getNumBuckets() const {
389 return static_cast<const DerivedT *>(this)->getNumBuckets();
391 BucketT *getBucketsEnd() {
392 return getBuckets() + getNumBuckets();
394 const BucketT *getBucketsEnd() const {
395 return getBuckets() + getNumBuckets();
398 void grow(unsigned AtLeast) {
399 static_cast<DerivedT *>(this)->grow(AtLeast);
402 void shrink_and_clear() {
403 static_cast<DerivedT *>(this)->shrink_and_clear();
407 BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
408 BucketT *TheBucket) {
409 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
411 TheBucket->getFirst() = Key;
412 new (&TheBucket->getSecond()) ValueT(Value);
416 BucketT *InsertIntoBucket(const KeyT &Key, ValueT &&Value,
417 BucketT *TheBucket) {
418 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
420 TheBucket->getFirst() = Key;
421 new (&TheBucket->getSecond()) ValueT(std::move(Value));
425 BucketT *InsertIntoBucket(KeyT &&Key, ValueT &&Value, BucketT *TheBucket) {
426 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
428 TheBucket->getFirst() = std::move(Key);
429 new (&TheBucket->getSecond()) ValueT(std::move(Value));
433 BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) {
434 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of
435 // the buckets are empty (meaning that many are filled with tombstones),
438 // The later case is tricky. For example, if we had one empty bucket with
439 // tons of tombstones, failing lookups (e.g. for insertion) would have to
440 // probe almost the entire table until it found the empty bucket. If the
441 // table completely filled with tombstones, no lookup would ever succeed,
442 // causing infinite loops in lookup.
443 unsigned NewNumEntries = getNumEntries() + 1;
444 unsigned NumBuckets = getNumBuckets();
445 if (NewNumEntries*4 >= NumBuckets*3) {
446 this->grow(NumBuckets * 2);
447 LookupBucketFor(Key, TheBucket);
448 NumBuckets = getNumBuckets();
449 } else if (NumBuckets-(NewNumEntries+getNumTombstones()) <= NumBuckets/8) {
450 this->grow(NumBuckets);
451 LookupBucketFor(Key, TheBucket);
455 // Only update the state after we've grown our bucket space appropriately
456 // so that when growing buckets we have self-consistent entry count.
457 incrementNumEntries();
459 // If we are writing over a tombstone, remember this.
460 const KeyT EmptyKey = getEmptyKey();
461 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
462 decrementNumTombstones();
467 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
468 /// FoundBucket. If the bucket contains the key and a value, this returns
469 /// true, otherwise it returns a bucket with an empty marker or tombstone and
471 template<typename LookupKeyT>
472 bool LookupBucketFor(const LookupKeyT &Val,
473 const BucketT *&FoundBucket) const {
474 const BucketT *BucketsPtr = getBuckets();
475 const unsigned NumBuckets = getNumBuckets();
477 if (NumBuckets == 0) {
478 FoundBucket = nullptr;
482 // FoundTombstone - Keep track of whether we find a tombstone while probing.
483 const BucketT *FoundTombstone = nullptr;
484 const KeyT EmptyKey = getEmptyKey();
485 const KeyT TombstoneKey = getTombstoneKey();
486 assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
487 !KeyInfoT::isEqual(Val, TombstoneKey) &&
488 "Empty/Tombstone value shouldn't be inserted into map!");
490 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
491 unsigned ProbeAmt = 1;
493 const BucketT *ThisBucket = BucketsPtr + BucketNo;
494 // Found Val's bucket? If so, return it.
495 if (KeyInfoT::isEqual(Val, ThisBucket->getFirst())) {
496 FoundBucket = ThisBucket;
500 // If we found an empty bucket, the key doesn't exist in the set.
501 // Insert it and return the default value.
502 if (KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey)) {
503 // If we've already seen a tombstone while probing, fill it in instead
504 // of the empty bucket we eventually probed to.
505 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
509 // If this is a tombstone, remember it. If Val ends up not in the map, we
510 // prefer to return it than something that would require more probing.
511 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
513 FoundTombstone = ThisBucket; // Remember the first tombstone found.
515 // Otherwise, it's a hash collision or a tombstone, continue quadratic
517 BucketNo += ProbeAmt++;
518 BucketNo &= (NumBuckets-1);
522 template <typename LookupKeyT>
523 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
524 const BucketT *ConstFoundBucket;
525 bool Result = const_cast<const DenseMapBase *>(this)
526 ->LookupBucketFor(Val, ConstFoundBucket);
527 FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
532 /// Return the approximate size (in bytes) of the actual map.
533 /// This is just the raw memory used by DenseMap.
534 /// If entries are pointers to objects, the size of the referenced objects
535 /// are not included.
536 size_t getMemorySize() const {
537 return getNumBuckets() * sizeof(BucketT);
541 template <typename KeyT, typename ValueT,
542 typename KeyInfoT = DenseMapInfo<KeyT>,
543 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
544 class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
545 KeyT, ValueT, KeyInfoT, BucketT> {
546 // Lift some types from the dependent base class into this class for
547 // simplicity of referring to them.
548 typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
549 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
553 unsigned NumTombstones;
557 explicit DenseMap(unsigned NumInitBuckets = 0) {
558 init(NumInitBuckets);
561 DenseMap(const DenseMap &other) : BaseT() {
566 DenseMap(DenseMap &&other) : BaseT() {
571 template<typename InputIt>
572 DenseMap(const InputIt &I, const InputIt &E) {
573 init(NextPowerOf2(std::distance(I, E)));
579 operator delete(Buckets);
582 void swap(DenseMap& RHS) {
583 std::swap(Buckets, RHS.Buckets);
584 std::swap(NumEntries, RHS.NumEntries);
585 std::swap(NumTombstones, RHS.NumTombstones);
586 std::swap(NumBuckets, RHS.NumBuckets);
589 DenseMap& operator=(const DenseMap& other) {
595 DenseMap& operator=(DenseMap &&other) {
597 operator delete(Buckets);
603 void copyFrom(const DenseMap& other) {
605 operator delete(Buckets);
606 if (allocateBuckets(other.NumBuckets)) {
607 this->BaseT::copyFrom(other);
614 void init(unsigned InitBuckets) {
615 if (allocateBuckets(InitBuckets)) {
616 this->BaseT::initEmpty();
623 void grow(unsigned AtLeast) {
624 unsigned OldNumBuckets = NumBuckets;
625 BucketT *OldBuckets = Buckets;
627 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
630 this->BaseT::initEmpty();
634 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
636 // Free the old table.
637 operator delete(OldBuckets);
640 void shrink_and_clear() {
641 unsigned OldNumEntries = NumEntries;
644 // Reduce the number of buckets.
645 unsigned NewNumBuckets = 0;
647 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
648 if (NewNumBuckets == NumBuckets) {
649 this->BaseT::initEmpty();
653 operator delete(Buckets);
658 unsigned getNumEntries() const {
661 void setNumEntries(unsigned Num) {
665 unsigned getNumTombstones() const {
666 return NumTombstones;
668 void setNumTombstones(unsigned Num) {
672 BucketT *getBuckets() const {
676 unsigned getNumBuckets() const {
680 bool allocateBuckets(unsigned Num) {
682 if (NumBuckets == 0) {
687 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets));
692 template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
693 typename KeyInfoT = DenseMapInfo<KeyT>,
694 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
696 : public DenseMapBase<
697 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
698 ValueT, KeyInfoT, BucketT> {
699 // Lift some types from the dependent base class into this class for
700 // simplicity of referring to them.
701 typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
702 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
705 unsigned NumEntries : 31;
706 unsigned NumTombstones;
713 /// A "union" of an inline bucket array and the struct representing
714 /// a large bucket. This union will be discriminated by the 'Small' bit.
715 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
718 explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
719 init(NumInitBuckets);
722 SmallDenseMap(const SmallDenseMap &other) : BaseT() {
727 SmallDenseMap(SmallDenseMap &&other) : BaseT() {
732 template<typename InputIt>
733 SmallDenseMap(const InputIt &I, const InputIt &E) {
734 init(NextPowerOf2(std::distance(I, E)));
743 void swap(SmallDenseMap& RHS) {
744 unsigned TmpNumEntries = RHS.NumEntries;
745 RHS.NumEntries = NumEntries;
746 NumEntries = TmpNumEntries;
747 std::swap(NumTombstones, RHS.NumTombstones);
749 const KeyT EmptyKey = this->getEmptyKey();
750 const KeyT TombstoneKey = this->getTombstoneKey();
751 if (Small && RHS.Small) {
752 // If we're swapping inline bucket arrays, we have to cope with some of
753 // the tricky bits of DenseMap's storage system: the buckets are not
754 // fully initialized. Thus we swap every key, but we may have
755 // a one-directional move of the value.
756 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
757 BucketT *LHSB = &getInlineBuckets()[i],
758 *RHSB = &RHS.getInlineBuckets()[i];
759 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
760 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
761 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
762 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
763 if (hasLHSValue && hasRHSValue) {
764 // Swap together if we can...
765 std::swap(*LHSB, *RHSB);
768 // Swap separately and handle any assymetry.
769 std::swap(LHSB->getFirst(), RHSB->getFirst());
771 new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
772 LHSB->getSecond().~ValueT();
773 } else if (hasRHSValue) {
774 new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
775 RHSB->getSecond().~ValueT();
780 if (!Small && !RHS.Small) {
781 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
782 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
786 SmallDenseMap &SmallSide = Small ? *this : RHS;
787 SmallDenseMap &LargeSide = Small ? RHS : *this;
789 // First stash the large side's rep and move the small side across.
790 LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
791 LargeSide.getLargeRep()->~LargeRep();
792 LargeSide.Small = true;
793 // This is similar to the standard move-from-old-buckets, but the bucket
794 // count hasn't actually rotated in this case. So we have to carefully
795 // move construct the keys and values into their new locations, but there
796 // is no need to re-hash things.
797 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
798 BucketT *NewB = &LargeSide.getInlineBuckets()[i],
799 *OldB = &SmallSide.getInlineBuckets()[i];
800 new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
801 OldB->getFirst().~KeyT();
802 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
803 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
804 new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
805 OldB->getSecond().~ValueT();
809 // The hard part of moving the small buckets across is done, just move
810 // the TmpRep into its new home.
811 SmallSide.Small = false;
812 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
815 SmallDenseMap& operator=(const SmallDenseMap& other) {
821 SmallDenseMap& operator=(SmallDenseMap &&other) {
829 void copyFrom(const SmallDenseMap& other) {
833 if (other.getNumBuckets() > InlineBuckets) {
835 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
837 this->BaseT::copyFrom(other);
840 void init(unsigned InitBuckets) {
842 if (InitBuckets > InlineBuckets) {
844 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
846 this->BaseT::initEmpty();
849 void grow(unsigned AtLeast) {
850 if (AtLeast >= InlineBuckets)
851 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
854 if (AtLeast < InlineBuckets)
855 return; // Nothing to do.
857 // First move the inline buckets into a temporary storage.
858 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
859 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer);
860 BucketT *TmpEnd = TmpBegin;
862 // Loop over the buckets, moving non-empty, non-tombstones into the
863 // temporary storage. Have the loop move the TmpEnd forward as it goes.
864 const KeyT EmptyKey = this->getEmptyKey();
865 const KeyT TombstoneKey = this->getTombstoneKey();
866 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
867 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
868 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
869 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
870 "Too many inline buckets!");
871 new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
872 new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
874 P->getSecond().~ValueT();
876 P->getFirst().~KeyT();
879 // Now make this map use the large rep, and move all the entries back
882 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
883 this->moveFromOldBuckets(TmpBegin, TmpEnd);
887 LargeRep OldRep = std::move(*getLargeRep());
888 getLargeRep()->~LargeRep();
889 if (AtLeast <= InlineBuckets) {
892 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
895 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
897 // Free the old table.
898 operator delete(OldRep.Buckets);
901 void shrink_and_clear() {
902 unsigned OldSize = this->size();
905 // Reduce the number of buckets.
906 unsigned NewNumBuckets = 0;
908 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
909 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
912 if ((Small && NewNumBuckets <= InlineBuckets) ||
913 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
914 this->BaseT::initEmpty();
923 unsigned getNumEntries() const {
926 void setNumEntries(unsigned Num) {
927 assert(Num < INT_MAX && "Cannot support more than INT_MAX entries");
931 unsigned getNumTombstones() const {
932 return NumTombstones;
934 void setNumTombstones(unsigned Num) {
938 const BucketT *getInlineBuckets() const {
940 // Note that this cast does not violate aliasing rules as we assert that
941 // the memory's dynamic type is the small, inline bucket buffer, and the
942 // 'storage.buffer' static type is 'char *'.
943 return reinterpret_cast<const BucketT *>(storage.buffer);
945 BucketT *getInlineBuckets() {
946 return const_cast<BucketT *>(
947 const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
949 const LargeRep *getLargeRep() const {
951 // Note, same rule about aliasing as with getInlineBuckets.
952 return reinterpret_cast<const LargeRep *>(storage.buffer);
954 LargeRep *getLargeRep() {
955 return const_cast<LargeRep *>(
956 const_cast<const SmallDenseMap *>(this)->getLargeRep());
959 const BucketT *getBuckets() const {
960 return Small ? getInlineBuckets() : getLargeRep()->Buckets;
962 BucketT *getBuckets() {
963 return const_cast<BucketT *>(
964 const_cast<const SmallDenseMap *>(this)->getBuckets());
966 unsigned getNumBuckets() const {
967 return Small ? InlineBuckets : getLargeRep()->NumBuckets;
970 void deallocateBuckets() {
974 operator delete(getLargeRep()->Buckets);
975 getLargeRep()->~LargeRep();
978 LargeRep allocateBuckets(unsigned Num) {
979 assert(Num > InlineBuckets && "Must allocate more buckets than are inline");
981 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num
987 template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
989 class DenseMapIterator {
990 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true> ConstIterator;
991 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
994 typedef ptrdiff_t difference_type;
995 typedef typename std::conditional<IsConst, const Bucket, Bucket>::type
997 typedef value_type *pointer;
998 typedef value_type &reference;
999 typedef std::forward_iterator_tag iterator_category;
1003 DenseMapIterator() : Ptr(nullptr), End(nullptr) {}
1005 DenseMapIterator(pointer Pos, pointer E, bool NoAdvance = false)
1006 : Ptr(Pos), End(E) {
1007 if (!NoAdvance) AdvancePastEmptyBuckets();
1010 // If IsConst is true this is a converting constructor from iterator to
1011 // const_iterator and the default copy constructor is used.
1012 // Otherwise this is a copy constructor for iterator.
1014 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false> &I)
1015 : Ptr(I.Ptr), End(I.End) {}
1017 reference operator*() const {
1020 pointer operator->() const {
1024 bool operator==(const ConstIterator &RHS) const {
1025 return Ptr == RHS.operator->();
1027 bool operator!=(const ConstIterator &RHS) const {
1028 return Ptr != RHS.operator->();
1031 inline DenseMapIterator& operator++() { // Preincrement
1033 AdvancePastEmptyBuckets();
1036 DenseMapIterator operator++(int) { // Postincrement
1037 DenseMapIterator tmp = *this; ++*this; return tmp;
1041 void AdvancePastEmptyBuckets() {
1042 const KeyT Empty = KeyInfoT::getEmptyKey();
1043 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1045 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
1046 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
1051 template<typename KeyT, typename ValueT, typename KeyInfoT>
1052 static inline size_t
1053 capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
1054 return X.getMemorySize();
1057 } // end namespace llvm