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/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/PointerLikeTypeTraits.h"
23 #include "llvm/Support/type_traits.h"
36 // We extend a pair to allow users to override the bucket type with their own
37 // implementation without requiring two members.
38 template <typename KeyT, typename ValueT>
39 struct DenseMapPair : public std::pair<KeyT, ValueT> {
40 KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
41 const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; }
42 ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; }
43 const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; }
48 typename KeyT, typename ValueT, typename KeyInfoT = DenseMapInfo<KeyT>,
49 typename Bucket = detail::DenseMapPair<KeyT, ValueT>, bool IsConst = false>
50 class DenseMapIterator;
52 template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
54 class DenseMapBase : public DebugEpochBase {
56 typedef unsigned size_type;
57 typedef KeyT key_type;
58 typedef ValueT mapped_type;
59 typedef BucketT value_type;
61 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT> iterator;
62 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>
64 inline iterator begin() {
65 // When the map is empty, avoid the overhead of AdvancePastEmptyBuckets().
66 return empty() ? end() : iterator(getBuckets(), getBucketsEnd(), *this);
68 inline iterator end() {
69 return iterator(getBucketsEnd(), getBucketsEnd(), *this, true);
71 inline const_iterator begin() const {
72 return empty() ? end()
73 : const_iterator(getBuckets(), getBucketsEnd(), *this);
75 inline const_iterator end() const {
76 return const_iterator(getBucketsEnd(), getBucketsEnd(), *this, true);
79 bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const {
80 return getNumEntries() == 0;
82 unsigned size() const { return getNumEntries(); }
84 /// Grow the densemap so that it has at least Size buckets. Does not shrink
85 void resize(size_type Size) {
87 if (Size > getNumBuckets())
93 if (getNumEntries() == 0 && getNumTombstones() == 0) return;
95 // If the capacity of the array is huge, and the # elements used is small,
97 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) {
102 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
103 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
104 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
105 if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
106 P->getSecond().~ValueT();
107 decrementNumEntries();
109 P->getFirst() = EmptyKey;
112 assert(getNumEntries() == 0 && "Node count imbalance!");
116 /// Return 1 if the specified key is in the map, 0 otherwise.
117 size_type count(const KeyT &Val) const {
118 const BucketT *TheBucket;
119 return LookupBucketFor(Val, TheBucket) ? 1 : 0;
122 iterator find(const KeyT &Val) {
124 if (LookupBucketFor(Val, TheBucket))
125 return iterator(TheBucket, getBucketsEnd(), *this, true);
128 const_iterator find(const KeyT &Val) const {
129 const BucketT *TheBucket;
130 if (LookupBucketFor(Val, TheBucket))
131 return const_iterator(TheBucket, getBucketsEnd(), *this, true);
135 /// Alternate version of find() which allows a different, and possibly
136 /// less expensive, key type.
137 /// The DenseMapInfo is responsible for supplying methods
138 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
140 template<class LookupKeyT>
141 iterator find_as(const LookupKeyT &Val) {
143 if (LookupBucketFor(Val, TheBucket))
144 return iterator(TheBucket, getBucketsEnd(), *this, true);
147 template<class LookupKeyT>
148 const_iterator find_as(const LookupKeyT &Val) const {
149 const BucketT *TheBucket;
150 if (LookupBucketFor(Val, TheBucket))
151 return const_iterator(TheBucket, getBucketsEnd(), *this, true);
155 /// lookup - Return the entry for the specified key, or a default
156 /// constructed value if no such entry exists.
157 ValueT lookup(const KeyT &Val) const {
158 const BucketT *TheBucket;
159 if (LookupBucketFor(Val, TheBucket))
160 return TheBucket->getSecond();
164 // Inserts key,value pair into the map if the key isn't already in the map.
165 // If the key is already in the map, it returns false and doesn't update the
167 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
169 if (LookupBucketFor(KV.first, TheBucket))
170 return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
171 false); // Already in map.
173 // Otherwise, insert the new element.
174 TheBucket = InsertIntoBucket(KV.first, KV.second, TheBucket);
175 return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
179 // Inserts key,value pair into the map if the key isn't already in the map.
180 // If the key is already in the map, it returns false and doesn't update the
182 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
184 if (LookupBucketFor(KV.first, TheBucket))
185 return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
186 false); // Already in map.
188 // Otherwise, insert the new element.
189 TheBucket = InsertIntoBucket(std::move(KV.first),
190 std::move(KV.second),
192 return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
196 /// insert - Range insertion of pairs.
197 template<typename InputIt>
198 void insert(InputIt I, InputIt E) {
204 bool erase(const KeyT &Val) {
206 if (!LookupBucketFor(Val, TheBucket))
207 return false; // not in map.
209 TheBucket->getSecond().~ValueT();
210 TheBucket->getFirst() = getTombstoneKey();
211 decrementNumEntries();
212 incrementNumTombstones();
215 void erase(iterator I) {
216 BucketT *TheBucket = &*I;
217 TheBucket->getSecond().~ValueT();
218 TheBucket->getFirst() = getTombstoneKey();
219 decrementNumEntries();
220 incrementNumTombstones();
223 value_type& FindAndConstruct(const KeyT &Key) {
225 if (LookupBucketFor(Key, TheBucket))
228 return *InsertIntoBucket(Key, ValueT(), TheBucket);
231 ValueT &operator[](const KeyT &Key) {
232 return FindAndConstruct(Key).second;
235 value_type& FindAndConstruct(KeyT &&Key) {
237 if (LookupBucketFor(Key, TheBucket))
240 return *InsertIntoBucket(std::move(Key), ValueT(), TheBucket);
243 ValueT &operator[](KeyT &&Key) {
244 return FindAndConstruct(std::move(Key)).second;
247 /// isPointerIntoBucketsArray - Return true if the specified pointer points
248 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or
249 /// value in the DenseMap).
250 bool isPointerIntoBucketsArray(const void *Ptr) const {
251 return Ptr >= getBuckets() && Ptr < getBucketsEnd();
254 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
255 /// array. In conjunction with the previous method, this can be used to
256 /// determine whether an insertion caused the DenseMap to reallocate.
257 const void *getPointerIntoBucketsArray() const { return getBuckets(); }
263 if (getNumBuckets() == 0) // Nothing to do.
266 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
267 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
268 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
269 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
270 P->getSecond().~ValueT();
271 P->getFirst().~KeyT();
275 memset((void*)getBuckets(), 0x5a, sizeof(BucketT)*getNumBuckets());
283 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&
284 "# initial buckets must be a power of two!");
285 const KeyT EmptyKey = getEmptyKey();
286 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
287 new (&B->getFirst()) KeyT(EmptyKey);
290 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
293 // Insert all the old elements.
294 const KeyT EmptyKey = getEmptyKey();
295 const KeyT TombstoneKey = getTombstoneKey();
296 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
297 if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) &&
298 !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) {
299 // Insert the key/value into the new table.
301 bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket);
302 (void)FoundVal; // silence warning.
303 assert(!FoundVal && "Key already in new map?");
304 DestBucket->getFirst() = std::move(B->getFirst());
305 new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
306 incrementNumEntries();
309 B->getSecond().~ValueT();
311 B->getFirst().~KeyT();
315 if (OldBucketsBegin != OldBucketsEnd)
316 memset((void*)OldBucketsBegin, 0x5a,
317 sizeof(BucketT) * (OldBucketsEnd - OldBucketsBegin));
321 template <typename OtherBaseT>
323 const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
324 assert(&other != this);
325 assert(getNumBuckets() == other.getNumBuckets());
327 setNumEntries(other.getNumEntries());
328 setNumTombstones(other.getNumTombstones());
330 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value)
331 memcpy(getBuckets(), other.getBuckets(),
332 getNumBuckets() * sizeof(BucketT));
334 for (size_t i = 0; i < getNumBuckets(); ++i) {
335 new (&getBuckets()[i].getFirst())
336 KeyT(other.getBuckets()[i].getFirst());
337 if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) &&
338 !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey()))
339 new (&getBuckets()[i].getSecond())
340 ValueT(other.getBuckets()[i].getSecond());
344 void swap(DenseMapBase& RHS) {
345 std::swap(getNumEntries(), RHS.getNumEntries());
346 std::swap(getNumTombstones(), RHS.getNumTombstones());
349 static unsigned getHashValue(const KeyT &Val) {
350 return KeyInfoT::getHashValue(Val);
352 template<typename LookupKeyT>
353 static unsigned getHashValue(const LookupKeyT &Val) {
354 return KeyInfoT::getHashValue(Val);
356 static const KeyT getEmptyKey() {
357 return KeyInfoT::getEmptyKey();
359 static const KeyT getTombstoneKey() {
360 return KeyInfoT::getTombstoneKey();
364 unsigned getNumEntries() const {
365 return static_cast<const DerivedT *>(this)->getNumEntries();
367 void setNumEntries(unsigned Num) {
368 static_cast<DerivedT *>(this)->setNumEntries(Num);
370 void incrementNumEntries() {
371 setNumEntries(getNumEntries() + 1);
373 void decrementNumEntries() {
374 setNumEntries(getNumEntries() - 1);
376 unsigned getNumTombstones() const {
377 return static_cast<const DerivedT *>(this)->getNumTombstones();
379 void setNumTombstones(unsigned Num) {
380 static_cast<DerivedT *>(this)->setNumTombstones(Num);
382 void incrementNumTombstones() {
383 setNumTombstones(getNumTombstones() + 1);
385 void decrementNumTombstones() {
386 setNumTombstones(getNumTombstones() - 1);
388 const BucketT *getBuckets() const {
389 return static_cast<const DerivedT *>(this)->getBuckets();
391 BucketT *getBuckets() {
392 return static_cast<DerivedT *>(this)->getBuckets();
394 unsigned getNumBuckets() const {
395 return static_cast<const DerivedT *>(this)->getNumBuckets();
397 BucketT *getBucketsEnd() {
398 return getBuckets() + getNumBuckets();
400 const BucketT *getBucketsEnd() const {
401 return getBuckets() + getNumBuckets();
404 void grow(unsigned AtLeast) {
405 static_cast<DerivedT *>(this)->grow(AtLeast);
408 void shrink_and_clear() {
409 static_cast<DerivedT *>(this)->shrink_and_clear();
413 BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
414 BucketT *TheBucket) {
415 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
417 TheBucket->getFirst() = Key;
418 new (&TheBucket->getSecond()) ValueT(Value);
422 BucketT *InsertIntoBucket(const KeyT &Key, ValueT &&Value,
423 BucketT *TheBucket) {
424 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
426 TheBucket->getFirst() = Key;
427 new (&TheBucket->getSecond()) ValueT(std::move(Value));
431 BucketT *InsertIntoBucket(KeyT &&Key, ValueT &&Value, BucketT *TheBucket) {
432 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
434 TheBucket->getFirst() = std::move(Key);
435 new (&TheBucket->getSecond()) ValueT(std::move(Value));
439 BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) {
442 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of
443 // the buckets are empty (meaning that many are filled with tombstones),
446 // The later case is tricky. For example, if we had one empty bucket with
447 // tons of tombstones, failing lookups (e.g. for insertion) would have to
448 // probe almost the entire table until it found the empty bucket. If the
449 // table completely filled with tombstones, no lookup would ever succeed,
450 // causing infinite loops in lookup.
451 unsigned NewNumEntries = getNumEntries() + 1;
452 unsigned NumBuckets = getNumBuckets();
453 if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)) {
454 this->grow(NumBuckets * 2);
455 LookupBucketFor(Key, TheBucket);
456 NumBuckets = getNumBuckets();
457 } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=
459 this->grow(NumBuckets);
460 LookupBucketFor(Key, TheBucket);
464 // Only update the state after we've grown our bucket space appropriately
465 // so that when growing buckets we have self-consistent entry count.
466 incrementNumEntries();
468 // If we are writing over a tombstone, remember this.
469 const KeyT EmptyKey = getEmptyKey();
470 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
471 decrementNumTombstones();
476 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
477 /// FoundBucket. If the bucket contains the key and a value, this returns
478 /// true, otherwise it returns a bucket with an empty marker or tombstone and
480 template<typename LookupKeyT>
481 bool LookupBucketFor(const LookupKeyT &Val,
482 const BucketT *&FoundBucket) const {
483 const BucketT *BucketsPtr = getBuckets();
484 const unsigned NumBuckets = getNumBuckets();
486 if (NumBuckets == 0) {
487 FoundBucket = nullptr;
491 // FoundTombstone - Keep track of whether we find a tombstone while probing.
492 const BucketT *FoundTombstone = nullptr;
493 const KeyT EmptyKey = getEmptyKey();
494 const KeyT TombstoneKey = getTombstoneKey();
495 assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
496 !KeyInfoT::isEqual(Val, TombstoneKey) &&
497 "Empty/Tombstone value shouldn't be inserted into map!");
499 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
500 unsigned ProbeAmt = 1;
502 const BucketT *ThisBucket = BucketsPtr + BucketNo;
503 // Found Val's bucket? If so, return it.
504 if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))) {
505 FoundBucket = ThisBucket;
509 // If we found an empty bucket, the key doesn't exist in the set.
510 // Insert it and return the default value.
511 if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))) {
512 // If we've already seen a tombstone while probing, fill it in instead
513 // of the empty bucket we eventually probed to.
514 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
518 // If this is a tombstone, remember it. If Val ends up not in the map, we
519 // prefer to return it than something that would require more probing.
520 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
522 FoundTombstone = ThisBucket; // Remember the first tombstone found.
524 // Otherwise, it's a hash collision or a tombstone, continue quadratic
526 BucketNo += ProbeAmt++;
527 BucketNo &= (NumBuckets-1);
531 template <typename LookupKeyT>
532 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
533 const BucketT *ConstFoundBucket;
534 bool Result = const_cast<const DenseMapBase *>(this)
535 ->LookupBucketFor(Val, ConstFoundBucket);
536 FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
541 /// Return the approximate size (in bytes) of the actual map.
542 /// This is just the raw memory used by DenseMap.
543 /// If entries are pointers to objects, the size of the referenced objects
544 /// are not included.
545 size_t getMemorySize() const {
546 return getNumBuckets() * sizeof(BucketT);
550 template <typename KeyT, typename ValueT,
551 typename KeyInfoT = DenseMapInfo<KeyT>,
552 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
553 class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
554 KeyT, ValueT, KeyInfoT, BucketT> {
555 // Lift some types from the dependent base class into this class for
556 // simplicity of referring to them.
557 typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
558 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
562 unsigned NumTombstones;
566 explicit DenseMap(unsigned NumInitBuckets = 0) {
567 init(NumInitBuckets);
570 DenseMap(const DenseMap &other) : BaseT() {
575 DenseMap(DenseMap &&other) : BaseT() {
580 template<typename InputIt>
581 DenseMap(const InputIt &I, const InputIt &E) {
582 init(NextPowerOf2(std::distance(I, E)));
588 operator delete(Buckets);
591 void swap(DenseMap& RHS) {
592 std::swap(Buckets, RHS.Buckets);
593 std::swap(NumEntries, RHS.NumEntries);
594 std::swap(NumTombstones, RHS.NumTombstones);
595 std::swap(NumBuckets, RHS.NumBuckets);
598 DenseMap& operator=(const DenseMap& other) {
604 DenseMap& operator=(DenseMap &&other) {
606 operator delete(Buckets);
612 void copyFrom(const DenseMap& other) {
614 operator delete(Buckets);
615 if (allocateBuckets(other.NumBuckets)) {
616 this->BaseT::copyFrom(other);
623 void init(unsigned InitBuckets) {
624 if (allocateBuckets(InitBuckets)) {
625 this->BaseT::initEmpty();
632 void grow(unsigned AtLeast) {
633 unsigned OldNumBuckets = NumBuckets;
634 BucketT *OldBuckets = Buckets;
636 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
639 this->BaseT::initEmpty();
643 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
645 // Free the old table.
646 operator delete(OldBuckets);
649 void shrink_and_clear() {
650 unsigned OldNumEntries = NumEntries;
653 // Reduce the number of buckets.
654 unsigned NewNumBuckets = 0;
656 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
657 if (NewNumBuckets == NumBuckets) {
658 this->BaseT::initEmpty();
662 operator delete(Buckets);
667 unsigned getNumEntries() const {
670 void setNumEntries(unsigned Num) {
674 unsigned getNumTombstones() const {
675 return NumTombstones;
677 void setNumTombstones(unsigned Num) {
681 BucketT *getBuckets() const {
685 unsigned getNumBuckets() const {
689 bool allocateBuckets(unsigned Num) {
691 if (NumBuckets == 0) {
696 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets));
701 template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
702 typename KeyInfoT = DenseMapInfo<KeyT>,
703 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
705 : public DenseMapBase<
706 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
707 ValueT, KeyInfoT, BucketT> {
708 // Lift some types from the dependent base class into this class for
709 // simplicity of referring to them.
710 typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
711 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
714 unsigned NumEntries : 31;
715 unsigned NumTombstones;
722 /// A "union" of an inline bucket array and the struct representing
723 /// a large bucket. This union will be discriminated by the 'Small' bit.
724 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
727 explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
728 init(NumInitBuckets);
731 SmallDenseMap(const SmallDenseMap &other) : BaseT() {
736 SmallDenseMap(SmallDenseMap &&other) : BaseT() {
741 template<typename InputIt>
742 SmallDenseMap(const InputIt &I, const InputIt &E) {
743 init(NextPowerOf2(std::distance(I, E)));
752 void swap(SmallDenseMap& RHS) {
753 unsigned TmpNumEntries = RHS.NumEntries;
754 RHS.NumEntries = NumEntries;
755 NumEntries = TmpNumEntries;
756 std::swap(NumTombstones, RHS.NumTombstones);
758 const KeyT EmptyKey = this->getEmptyKey();
759 const KeyT TombstoneKey = this->getTombstoneKey();
760 if (Small && RHS.Small) {
761 // If we're swapping inline bucket arrays, we have to cope with some of
762 // the tricky bits of DenseMap's storage system: the buckets are not
763 // fully initialized. Thus we swap every key, but we may have
764 // a one-directional move of the value.
765 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
766 BucketT *LHSB = &getInlineBuckets()[i],
767 *RHSB = &RHS.getInlineBuckets()[i];
768 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
769 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
770 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
771 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
772 if (hasLHSValue && hasRHSValue) {
773 // Swap together if we can...
774 std::swap(*LHSB, *RHSB);
777 // Swap separately and handle any assymetry.
778 std::swap(LHSB->getFirst(), RHSB->getFirst());
780 new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
781 LHSB->getSecond().~ValueT();
782 } else if (hasRHSValue) {
783 new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
784 RHSB->getSecond().~ValueT();
789 if (!Small && !RHS.Small) {
790 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
791 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
795 SmallDenseMap &SmallSide = Small ? *this : RHS;
796 SmallDenseMap &LargeSide = Small ? RHS : *this;
798 // First stash the large side's rep and move the small side across.
799 LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
800 LargeSide.getLargeRep()->~LargeRep();
801 LargeSide.Small = true;
802 // This is similar to the standard move-from-old-buckets, but the bucket
803 // count hasn't actually rotated in this case. So we have to carefully
804 // move construct the keys and values into their new locations, but there
805 // is no need to re-hash things.
806 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
807 BucketT *NewB = &LargeSide.getInlineBuckets()[i],
808 *OldB = &SmallSide.getInlineBuckets()[i];
809 new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
810 OldB->getFirst().~KeyT();
811 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
812 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
813 new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
814 OldB->getSecond().~ValueT();
818 // The hard part of moving the small buckets across is done, just move
819 // the TmpRep into its new home.
820 SmallSide.Small = false;
821 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
824 SmallDenseMap& operator=(const SmallDenseMap& other) {
830 SmallDenseMap& operator=(SmallDenseMap &&other) {
838 void copyFrom(const SmallDenseMap& other) {
842 if (other.getNumBuckets() > InlineBuckets) {
844 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
846 this->BaseT::copyFrom(other);
849 void init(unsigned InitBuckets) {
851 if (InitBuckets > InlineBuckets) {
853 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
855 this->BaseT::initEmpty();
858 void grow(unsigned AtLeast) {
859 if (AtLeast >= InlineBuckets)
860 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
863 if (AtLeast < InlineBuckets)
864 return; // Nothing to do.
866 // First move the inline buckets into a temporary storage.
867 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
868 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer);
869 BucketT *TmpEnd = TmpBegin;
871 // Loop over the buckets, moving non-empty, non-tombstones into the
872 // temporary storage. Have the loop move the TmpEnd forward as it goes.
873 const KeyT EmptyKey = this->getEmptyKey();
874 const KeyT TombstoneKey = this->getTombstoneKey();
875 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
876 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
877 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
878 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
879 "Too many inline buckets!");
880 new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
881 new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
883 P->getSecond().~ValueT();
885 P->getFirst().~KeyT();
888 // Now make this map use the large rep, and move all the entries back
891 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
892 this->moveFromOldBuckets(TmpBegin, TmpEnd);
896 LargeRep OldRep = std::move(*getLargeRep());
897 getLargeRep()->~LargeRep();
898 if (AtLeast <= InlineBuckets) {
901 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
904 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
906 // Free the old table.
907 operator delete(OldRep.Buckets);
910 void shrink_and_clear() {
911 unsigned OldSize = this->size();
914 // Reduce the number of buckets.
915 unsigned NewNumBuckets = 0;
917 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
918 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
921 if ((Small && NewNumBuckets <= InlineBuckets) ||
922 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
923 this->BaseT::initEmpty();
932 unsigned getNumEntries() const {
935 void setNumEntries(unsigned Num) {
936 assert(Num < INT_MAX && "Cannot support more than INT_MAX entries");
940 unsigned getNumTombstones() const {
941 return NumTombstones;
943 void setNumTombstones(unsigned Num) {
947 const BucketT *getInlineBuckets() const {
949 // Note that this cast does not violate aliasing rules as we assert that
950 // the memory's dynamic type is the small, inline bucket buffer, and the
951 // 'storage.buffer' static type is 'char *'.
952 return reinterpret_cast<const BucketT *>(storage.buffer);
954 BucketT *getInlineBuckets() {
955 return const_cast<BucketT *>(
956 const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
958 const LargeRep *getLargeRep() const {
960 // Note, same rule about aliasing as with getInlineBuckets.
961 return reinterpret_cast<const LargeRep *>(storage.buffer);
963 LargeRep *getLargeRep() {
964 return const_cast<LargeRep *>(
965 const_cast<const SmallDenseMap *>(this)->getLargeRep());
968 const BucketT *getBuckets() const {
969 return Small ? getInlineBuckets() : getLargeRep()->Buckets;
971 BucketT *getBuckets() {
972 return const_cast<BucketT *>(
973 const_cast<const SmallDenseMap *>(this)->getBuckets());
975 unsigned getNumBuckets() const {
976 return Small ? InlineBuckets : getLargeRep()->NumBuckets;
979 void deallocateBuckets() {
983 operator delete(getLargeRep()->Buckets);
984 getLargeRep()->~LargeRep();
987 LargeRep allocateBuckets(unsigned Num) {
988 assert(Num > InlineBuckets && "Must allocate more buckets than are inline");
990 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num
996 template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
998 class DenseMapIterator : DebugEpochBase::HandleBase {
999 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true> ConstIterator;
1000 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
1001 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>;
1004 typedef ptrdiff_t difference_type;
1005 typedef typename std::conditional<IsConst, const Bucket, Bucket>::type
1007 typedef value_type *pointer;
1008 typedef value_type &reference;
1009 typedef std::forward_iterator_tag iterator_category;
1013 DenseMapIterator() : Ptr(nullptr), End(nullptr) {}
1015 DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch,
1016 bool NoAdvance = false)
1017 : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) {
1018 assert(isHandleInSync() && "invalid construction!");
1019 if (!NoAdvance) AdvancePastEmptyBuckets();
1022 // Converting ctor from non-const iterators to const iterators. SFINAE'd out
1023 // for const iterator destinations so it doesn't end up as a user defined copy
1025 template <bool IsConstSrc,
1026 typename = typename std::enable_if<!IsConstSrc && IsConst>::type>
1028 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I)
1029 : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {}
1031 reference operator*() const {
1032 assert(isHandleInSync() && "invalid iterator access!");
1035 pointer operator->() const {
1036 assert(isHandleInSync() && "invalid iterator access!");
1040 bool operator==(const ConstIterator &RHS) const {
1041 assert((!Ptr || isHandleInSync()) && "handle not in sync!");
1042 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1043 assert(getEpochAddress() == RHS.getEpochAddress() &&
1044 "comparing incomparable iterators!");
1045 return Ptr == RHS.Ptr;
1047 bool operator!=(const ConstIterator &RHS) const {
1048 assert((!Ptr || isHandleInSync()) && "handle not in sync!");
1049 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1050 assert(getEpochAddress() == RHS.getEpochAddress() &&
1051 "comparing incomparable iterators!");
1052 return Ptr != RHS.Ptr;
1055 inline DenseMapIterator& operator++() { // Preincrement
1056 assert(isHandleInSync() && "invalid iterator access!");
1058 AdvancePastEmptyBuckets();
1061 DenseMapIterator operator++(int) { // Postincrement
1062 assert(isHandleInSync() && "invalid iterator access!");
1063 DenseMapIterator tmp = *this; ++*this; return tmp;
1067 void AdvancePastEmptyBuckets() {
1068 const KeyT Empty = KeyInfoT::getEmptyKey();
1069 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1071 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
1072 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
1077 template<typename KeyT, typename ValueT, typename KeyInfoT>
1078 static inline size_t
1079 capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
1080 return X.getMemorySize();
1083 } // end namespace llvm