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 static unsigned getHashValue(const KeyT &Val) {
345 return KeyInfoT::getHashValue(Val);
347 template<typename LookupKeyT>
348 static unsigned getHashValue(const LookupKeyT &Val) {
349 return KeyInfoT::getHashValue(Val);
351 static const KeyT getEmptyKey() {
352 return KeyInfoT::getEmptyKey();
354 static const KeyT getTombstoneKey() {
355 return KeyInfoT::getTombstoneKey();
359 unsigned getNumEntries() const {
360 return static_cast<const DerivedT *>(this)->getNumEntries();
362 void setNumEntries(unsigned Num) {
363 static_cast<DerivedT *>(this)->setNumEntries(Num);
365 void incrementNumEntries() {
366 setNumEntries(getNumEntries() + 1);
368 void decrementNumEntries() {
369 setNumEntries(getNumEntries() - 1);
371 unsigned getNumTombstones() const {
372 return static_cast<const DerivedT *>(this)->getNumTombstones();
374 void setNumTombstones(unsigned Num) {
375 static_cast<DerivedT *>(this)->setNumTombstones(Num);
377 void incrementNumTombstones() {
378 setNumTombstones(getNumTombstones() + 1);
380 void decrementNumTombstones() {
381 setNumTombstones(getNumTombstones() - 1);
383 const BucketT *getBuckets() const {
384 return static_cast<const DerivedT *>(this)->getBuckets();
386 BucketT *getBuckets() {
387 return static_cast<DerivedT *>(this)->getBuckets();
389 unsigned getNumBuckets() const {
390 return static_cast<const DerivedT *>(this)->getNumBuckets();
392 BucketT *getBucketsEnd() {
393 return getBuckets() + getNumBuckets();
395 const BucketT *getBucketsEnd() const {
396 return getBuckets() + getNumBuckets();
399 void grow(unsigned AtLeast) {
400 static_cast<DerivedT *>(this)->grow(AtLeast);
403 void shrink_and_clear() {
404 static_cast<DerivedT *>(this)->shrink_and_clear();
408 BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
409 BucketT *TheBucket) {
410 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
412 TheBucket->getFirst() = Key;
413 new (&TheBucket->getSecond()) ValueT(Value);
417 BucketT *InsertIntoBucket(const KeyT &Key, ValueT &&Value,
418 BucketT *TheBucket) {
419 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
421 TheBucket->getFirst() = Key;
422 new (&TheBucket->getSecond()) ValueT(std::move(Value));
426 BucketT *InsertIntoBucket(KeyT &&Key, ValueT &&Value, BucketT *TheBucket) {
427 TheBucket = InsertIntoBucketImpl(Key, TheBucket);
429 TheBucket->getFirst() = std::move(Key);
430 new (&TheBucket->getSecond()) ValueT(std::move(Value));
434 BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) {
437 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of
438 // the buckets are empty (meaning that many are filled with tombstones),
441 // The later case is tricky. For example, if we had one empty bucket with
442 // tons of tombstones, failing lookups (e.g. for insertion) would have to
443 // probe almost the entire table until it found the empty bucket. If the
444 // table completely filled with tombstones, no lookup would ever succeed,
445 // causing infinite loops in lookup.
446 unsigned NewNumEntries = getNumEntries() + 1;
447 unsigned NumBuckets = getNumBuckets();
448 if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)) {
449 this->grow(NumBuckets * 2);
450 LookupBucketFor(Key, TheBucket);
451 NumBuckets = getNumBuckets();
452 } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=
454 this->grow(NumBuckets);
455 LookupBucketFor(Key, TheBucket);
459 // Only update the state after we've grown our bucket space appropriately
460 // so that when growing buckets we have self-consistent entry count.
461 incrementNumEntries();
463 // If we are writing over a tombstone, remember this.
464 const KeyT EmptyKey = getEmptyKey();
465 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
466 decrementNumTombstones();
471 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
472 /// FoundBucket. If the bucket contains the key and a value, this returns
473 /// true, otherwise it returns a bucket with an empty marker or tombstone and
475 template<typename LookupKeyT>
476 bool LookupBucketFor(const LookupKeyT &Val,
477 const BucketT *&FoundBucket) const {
478 const BucketT *BucketsPtr = getBuckets();
479 const unsigned NumBuckets = getNumBuckets();
481 if (NumBuckets == 0) {
482 FoundBucket = nullptr;
486 // FoundTombstone - Keep track of whether we find a tombstone while probing.
487 const BucketT *FoundTombstone = nullptr;
488 const KeyT EmptyKey = getEmptyKey();
489 const KeyT TombstoneKey = getTombstoneKey();
490 assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
491 !KeyInfoT::isEqual(Val, TombstoneKey) &&
492 "Empty/Tombstone value shouldn't be inserted into map!");
494 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
495 unsigned ProbeAmt = 1;
497 const BucketT *ThisBucket = BucketsPtr + BucketNo;
498 // Found Val's bucket? If so, return it.
499 if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))) {
500 FoundBucket = ThisBucket;
504 // If we found an empty bucket, the key doesn't exist in the set.
505 // Insert it and return the default value.
506 if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))) {
507 // If we've already seen a tombstone while probing, fill it in instead
508 // of the empty bucket we eventually probed to.
509 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
513 // If this is a tombstone, remember it. If Val ends up not in the map, we
514 // prefer to return it than something that would require more probing.
515 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
517 FoundTombstone = ThisBucket; // Remember the first tombstone found.
519 // Otherwise, it's a hash collision or a tombstone, continue quadratic
521 BucketNo += ProbeAmt++;
522 BucketNo &= (NumBuckets-1);
526 template <typename LookupKeyT>
527 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
528 const BucketT *ConstFoundBucket;
529 bool Result = const_cast<const DenseMapBase *>(this)
530 ->LookupBucketFor(Val, ConstFoundBucket);
531 FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
536 /// Return the approximate size (in bytes) of the actual map.
537 /// This is just the raw memory used by DenseMap.
538 /// If entries are pointers to objects, the size of the referenced objects
539 /// are not included.
540 size_t getMemorySize() const {
541 return getNumBuckets() * sizeof(BucketT);
545 template <typename KeyT, typename ValueT,
546 typename KeyInfoT = DenseMapInfo<KeyT>,
547 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
548 class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
549 KeyT, ValueT, KeyInfoT, BucketT> {
550 // Lift some types from the dependent base class into this class for
551 // simplicity of referring to them.
552 typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
553 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
557 unsigned NumTombstones;
561 explicit DenseMap(unsigned NumInitBuckets = 0) {
562 init(NumInitBuckets);
565 DenseMap(const DenseMap &other) : BaseT() {
570 DenseMap(DenseMap &&other) : BaseT() {
575 template<typename InputIt>
576 DenseMap(const InputIt &I, const InputIt &E) {
577 init(NextPowerOf2(std::distance(I, E)));
583 operator delete(Buckets);
586 void swap(DenseMap& RHS) {
587 this->incrementEpoch();
588 RHS.incrementEpoch();
589 std::swap(Buckets, RHS.Buckets);
590 std::swap(NumEntries, RHS.NumEntries);
591 std::swap(NumTombstones, RHS.NumTombstones);
592 std::swap(NumBuckets, RHS.NumBuckets);
595 DenseMap& operator=(const DenseMap& other) {
601 DenseMap& operator=(DenseMap &&other) {
603 operator delete(Buckets);
609 void copyFrom(const DenseMap& other) {
611 operator delete(Buckets);
612 if (allocateBuckets(other.NumBuckets)) {
613 this->BaseT::copyFrom(other);
620 void init(unsigned InitBuckets) {
621 if (allocateBuckets(InitBuckets)) {
622 this->BaseT::initEmpty();
629 void grow(unsigned AtLeast) {
630 unsigned OldNumBuckets = NumBuckets;
631 BucketT *OldBuckets = Buckets;
633 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
636 this->BaseT::initEmpty();
640 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
642 // Free the old table.
643 operator delete(OldBuckets);
646 void shrink_and_clear() {
647 unsigned OldNumEntries = NumEntries;
650 // Reduce the number of buckets.
651 unsigned NewNumBuckets = 0;
653 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
654 if (NewNumBuckets == NumBuckets) {
655 this->BaseT::initEmpty();
659 operator delete(Buckets);
664 unsigned getNumEntries() const {
667 void setNumEntries(unsigned Num) {
671 unsigned getNumTombstones() const {
672 return NumTombstones;
674 void setNumTombstones(unsigned Num) {
678 BucketT *getBuckets() const {
682 unsigned getNumBuckets() const {
686 bool allocateBuckets(unsigned Num) {
688 if (NumBuckets == 0) {
693 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets));
698 template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
699 typename KeyInfoT = DenseMapInfo<KeyT>,
700 typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
702 : public DenseMapBase<
703 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
704 ValueT, KeyInfoT, BucketT> {
705 // Lift some types from the dependent base class into this class for
706 // simplicity of referring to them.
707 typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
708 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
711 unsigned NumEntries : 31;
712 unsigned NumTombstones;
719 /// A "union" of an inline bucket array and the struct representing
720 /// a large bucket. This union will be discriminated by the 'Small' bit.
721 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
724 explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
725 init(NumInitBuckets);
728 SmallDenseMap(const SmallDenseMap &other) : BaseT() {
733 SmallDenseMap(SmallDenseMap &&other) : BaseT() {
738 template<typename InputIt>
739 SmallDenseMap(const InputIt &I, const InputIt &E) {
740 init(NextPowerOf2(std::distance(I, E)));
749 void swap(SmallDenseMap& RHS) {
750 unsigned TmpNumEntries = RHS.NumEntries;
751 RHS.NumEntries = NumEntries;
752 NumEntries = TmpNumEntries;
753 std::swap(NumTombstones, RHS.NumTombstones);
755 const KeyT EmptyKey = this->getEmptyKey();
756 const KeyT TombstoneKey = this->getTombstoneKey();
757 if (Small && RHS.Small) {
758 // If we're swapping inline bucket arrays, we have to cope with some of
759 // the tricky bits of DenseMap's storage system: the buckets are not
760 // fully initialized. Thus we swap every key, but we may have
761 // a one-directional move of the value.
762 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
763 BucketT *LHSB = &getInlineBuckets()[i],
764 *RHSB = &RHS.getInlineBuckets()[i];
765 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
766 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
767 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
768 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
769 if (hasLHSValue && hasRHSValue) {
770 // Swap together if we can...
771 std::swap(*LHSB, *RHSB);
774 // Swap separately and handle any assymetry.
775 std::swap(LHSB->getFirst(), RHSB->getFirst());
777 new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
778 LHSB->getSecond().~ValueT();
779 } else if (hasRHSValue) {
780 new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
781 RHSB->getSecond().~ValueT();
786 if (!Small && !RHS.Small) {
787 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
788 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
792 SmallDenseMap &SmallSide = Small ? *this : RHS;
793 SmallDenseMap &LargeSide = Small ? RHS : *this;
795 // First stash the large side's rep and move the small side across.
796 LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
797 LargeSide.getLargeRep()->~LargeRep();
798 LargeSide.Small = true;
799 // This is similar to the standard move-from-old-buckets, but the bucket
800 // count hasn't actually rotated in this case. So we have to carefully
801 // move construct the keys and values into their new locations, but there
802 // is no need to re-hash things.
803 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
804 BucketT *NewB = &LargeSide.getInlineBuckets()[i],
805 *OldB = &SmallSide.getInlineBuckets()[i];
806 new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
807 OldB->getFirst().~KeyT();
808 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
809 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
810 new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
811 OldB->getSecond().~ValueT();
815 // The hard part of moving the small buckets across is done, just move
816 // the TmpRep into its new home.
817 SmallSide.Small = false;
818 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
821 SmallDenseMap& operator=(const SmallDenseMap& other) {
827 SmallDenseMap& operator=(SmallDenseMap &&other) {
835 void copyFrom(const SmallDenseMap& other) {
839 if (other.getNumBuckets() > InlineBuckets) {
841 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
843 this->BaseT::copyFrom(other);
846 void init(unsigned InitBuckets) {
848 if (InitBuckets > InlineBuckets) {
850 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
852 this->BaseT::initEmpty();
855 void grow(unsigned AtLeast) {
856 if (AtLeast >= InlineBuckets)
857 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
860 if (AtLeast < InlineBuckets)
861 return; // Nothing to do.
863 // First move the inline buckets into a temporary storage.
864 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
865 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer);
866 BucketT *TmpEnd = TmpBegin;
868 // Loop over the buckets, moving non-empty, non-tombstones into the
869 // temporary storage. Have the loop move the TmpEnd forward as it goes.
870 const KeyT EmptyKey = this->getEmptyKey();
871 const KeyT TombstoneKey = this->getTombstoneKey();
872 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
873 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
874 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
875 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
876 "Too many inline buckets!");
877 new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
878 new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
880 P->getSecond().~ValueT();
882 P->getFirst().~KeyT();
885 // Now make this map use the large rep, and move all the entries back
888 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
889 this->moveFromOldBuckets(TmpBegin, TmpEnd);
893 LargeRep OldRep = std::move(*getLargeRep());
894 getLargeRep()->~LargeRep();
895 if (AtLeast <= InlineBuckets) {
898 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
901 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
903 // Free the old table.
904 operator delete(OldRep.Buckets);
907 void shrink_and_clear() {
908 unsigned OldSize = this->size();
911 // Reduce the number of buckets.
912 unsigned NewNumBuckets = 0;
914 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
915 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
918 if ((Small && NewNumBuckets <= InlineBuckets) ||
919 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
920 this->BaseT::initEmpty();
929 unsigned getNumEntries() const {
932 void setNumEntries(unsigned Num) {
933 assert(Num < INT_MAX && "Cannot support more than INT_MAX entries");
937 unsigned getNumTombstones() const {
938 return NumTombstones;
940 void setNumTombstones(unsigned Num) {
944 const BucketT *getInlineBuckets() const {
946 // Note that this cast does not violate aliasing rules as we assert that
947 // the memory's dynamic type is the small, inline bucket buffer, and the
948 // 'storage.buffer' static type is 'char *'.
949 return reinterpret_cast<const BucketT *>(storage.buffer);
951 BucketT *getInlineBuckets() {
952 return const_cast<BucketT *>(
953 const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
955 const LargeRep *getLargeRep() const {
957 // Note, same rule about aliasing as with getInlineBuckets.
958 return reinterpret_cast<const LargeRep *>(storage.buffer);
960 LargeRep *getLargeRep() {
961 return const_cast<LargeRep *>(
962 const_cast<const SmallDenseMap *>(this)->getLargeRep());
965 const BucketT *getBuckets() const {
966 return Small ? getInlineBuckets() : getLargeRep()->Buckets;
968 BucketT *getBuckets() {
969 return const_cast<BucketT *>(
970 const_cast<const SmallDenseMap *>(this)->getBuckets());
972 unsigned getNumBuckets() const {
973 return Small ? InlineBuckets : getLargeRep()->NumBuckets;
976 void deallocateBuckets() {
980 operator delete(getLargeRep()->Buckets);
981 getLargeRep()->~LargeRep();
984 LargeRep allocateBuckets(unsigned Num) {
985 assert(Num > InlineBuckets && "Must allocate more buckets than are inline");
987 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num
993 template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
995 class DenseMapIterator : DebugEpochBase::HandleBase {
996 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true> ConstIterator;
997 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
998 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>;
1001 typedef ptrdiff_t difference_type;
1002 typedef typename std::conditional<IsConst, const Bucket, Bucket>::type
1004 typedef value_type *pointer;
1005 typedef value_type &reference;
1006 typedef std::forward_iterator_tag iterator_category;
1010 DenseMapIterator() : Ptr(nullptr), End(nullptr) {}
1012 DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch,
1013 bool NoAdvance = false)
1014 : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) {
1015 assert(isHandleInSync() && "invalid construction!");
1016 if (!NoAdvance) AdvancePastEmptyBuckets();
1019 // Converting ctor from non-const iterators to const iterators. SFINAE'd out
1020 // for const iterator destinations so it doesn't end up as a user defined copy
1022 template <bool IsConstSrc,
1023 typename = typename std::enable_if<!IsConstSrc && IsConst>::type>
1025 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I)
1026 : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {}
1028 reference operator*() const {
1029 assert(isHandleInSync() && "invalid iterator access!");
1032 pointer operator->() const {
1033 assert(isHandleInSync() && "invalid iterator access!");
1037 bool operator==(const ConstIterator &RHS) const {
1038 assert((!Ptr || isHandleInSync()) && "handle not in sync!");
1039 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1040 assert(getEpochAddress() == RHS.getEpochAddress() &&
1041 "comparing incomparable iterators!");
1042 return Ptr == RHS.Ptr;
1044 bool operator!=(const ConstIterator &RHS) const {
1045 assert((!Ptr || isHandleInSync()) && "handle not in sync!");
1046 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!");
1047 assert(getEpochAddress() == RHS.getEpochAddress() &&
1048 "comparing incomparable iterators!");
1049 return Ptr != RHS.Ptr;
1052 inline DenseMapIterator& operator++() { // Preincrement
1053 assert(isHandleInSync() && "invalid iterator access!");
1055 AdvancePastEmptyBuckets();
1058 DenseMapIterator operator++(int) { // Postincrement
1059 assert(isHandleInSync() && "invalid iterator access!");
1060 DenseMapIterator tmp = *this; ++*this; return tmp;
1064 void AdvancePastEmptyBuckets() {
1065 const KeyT Empty = KeyInfoT::getEmptyKey();
1066 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1068 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
1069 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
1074 template<typename KeyT, typename ValueT, typename KeyInfoT>
1075 static inline size_t
1076 capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
1077 return X.getMemorySize();
1080 } // end namespace llvm