DenseMap.h revision 2aaa47f396f185d28aa7855d345f7385681098e2
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/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" 23#include <algorithm> 24#include <cassert> 25#include <climits> 26#include <cstddef> 27#include <cstring> 28#include <iterator> 29#include <new> 30#include <utility> 31 32namespace llvm { 33 34template<typename KeyT, typename ValueT, 35 typename KeyInfoT = DenseMapInfo<KeyT>, 36 bool IsConst = false> 37class DenseMapIterator; 38 39template<typename DerivedT, 40 typename KeyT, typename ValueT, typename KeyInfoT> 41class DenseMapBase { 42protected: 43 typedef std::pair<KeyT, ValueT> BucketT; 44 45public: 46 typedef KeyT key_type; 47 typedef ValueT mapped_type; 48 typedef BucketT value_type; 49 50 typedef DenseMapIterator<KeyT, ValueT, KeyInfoT> iterator; 51 typedef DenseMapIterator<KeyT, ValueT, 52 KeyInfoT, true> const_iterator; 53 inline iterator begin() { 54 // When the map is empty, avoid the overhead of AdvancePastEmptyBuckets(). 55 return empty() ? end() : iterator(getBuckets(), getBucketsEnd()); 56 } 57 inline iterator end() { 58 return iterator(getBucketsEnd(), getBucketsEnd(), true); 59 } 60 inline const_iterator begin() const { 61 return empty() ? end() : const_iterator(getBuckets(), getBucketsEnd()); 62 } 63 inline const_iterator end() const { 64 return const_iterator(getBucketsEnd(), getBucketsEnd(), true); 65 } 66 67 bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { 68 return getNumEntries() == 0; 69 } 70 unsigned size() const { return getNumEntries(); } 71 72 /// Grow the densemap so that it has at least Size buckets. Does not shrink 73 void resize(size_t Size) { 74 if (Size > getNumBuckets()) 75 grow(Size); 76 } 77 78 void clear() { 79 if (getNumEntries() == 0 && getNumTombstones() == 0) return; 80 81 // If the capacity of the array is huge, and the # elements used is small, 82 // shrink the array. 83 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) { 84 shrink_and_clear(); 85 return; 86 } 87 88 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); 89 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { 90 if (!KeyInfoT::isEqual(P->first, EmptyKey)) { 91 if (!KeyInfoT::isEqual(P->first, TombstoneKey)) { 92 P->second.~ValueT(); 93 decrementNumEntries(); 94 } 95 P->first = EmptyKey; 96 } 97 } 98 assert(getNumEntries() == 0 && "Node count imbalance!"); 99 setNumTombstones(0); 100 } 101 102 /// count - Return true if the specified key is in the map. 103 bool count(const KeyT &Val) const { 104 const BucketT *TheBucket; 105 return LookupBucketFor(Val, TheBucket); 106 } 107 108 iterator find(const KeyT &Val) { 109 BucketT *TheBucket; 110 if (LookupBucketFor(Val, TheBucket)) 111 return iterator(TheBucket, getBucketsEnd(), true); 112 return end(); 113 } 114 const_iterator find(const KeyT &Val) const { 115 const BucketT *TheBucket; 116 if (LookupBucketFor(Val, TheBucket)) 117 return const_iterator(TheBucket, getBucketsEnd(), true); 118 return end(); 119 } 120 121 /// Alternate version of find() which allows a different, and possibly 122 /// less expensive, key type. 123 /// The DenseMapInfo is responsible for supplying methods 124 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key 125 /// type used. 126 template<class LookupKeyT> 127 iterator find_as(const LookupKeyT &Val) { 128 BucketT *TheBucket; 129 if (LookupBucketFor(Val, TheBucket)) 130 return iterator(TheBucket, getBucketsEnd(), true); 131 return end(); 132 } 133 template<class LookupKeyT> 134 const_iterator find_as(const LookupKeyT &Val) const { 135 const BucketT *TheBucket; 136 if (LookupBucketFor(Val, TheBucket)) 137 return const_iterator(TheBucket, getBucketsEnd(), true); 138 return end(); 139 } 140 141 /// lookup - Return the entry for the specified key, or a default 142 /// constructed value if no such entry exists. 143 ValueT lookup(const KeyT &Val) const { 144 const BucketT *TheBucket; 145 if (LookupBucketFor(Val, TheBucket)) 146 return TheBucket->second; 147 return ValueT(); 148 } 149 150 // Inserts key,value pair into the map if the key isn't already in the map. 151 // If the key is already in the map, it returns false and doesn't update the 152 // value. 153 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) { 154 BucketT *TheBucket; 155 if (LookupBucketFor(KV.first, TheBucket)) 156 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), 157 false); // Already in map. 158 159 // Otherwise, insert the new element. 160 TheBucket = InsertIntoBucket(KV.first, KV.second, TheBucket); 161 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true); 162 } 163 164#if LLVM_HAS_RVALUE_REFERENCES 165 // Inserts key,value pair into the map if the key isn't already in the map. 166 // If the key is already in the map, it returns false and doesn't update the 167 // value. 168 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) { 169 BucketT *TheBucket; 170 if (LookupBucketFor(KV.first, TheBucket)) 171 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), 172 false); // Already in map. 173 174 // Otherwise, insert the new element. 175 TheBucket = InsertIntoBucket(std::move(KV.first), 176 std::move(KV.second), 177 TheBucket); 178 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true); 179 } 180#endif 181 182 /// insert - Range insertion of pairs. 183 template<typename InputIt> 184 void insert(InputIt I, InputIt E) { 185 for (; I != E; ++I) 186 insert(*I); 187 } 188 189 190 bool erase(const KeyT &Val) { 191 BucketT *TheBucket; 192 if (!LookupBucketFor(Val, TheBucket)) 193 return false; // not in map. 194 195 TheBucket->second.~ValueT(); 196 TheBucket->first = getTombstoneKey(); 197 decrementNumEntries(); 198 incrementNumTombstones(); 199 return true; 200 } 201 void erase(iterator I) { 202 BucketT *TheBucket = &*I; 203 TheBucket->second.~ValueT(); 204 TheBucket->first = getTombstoneKey(); 205 decrementNumEntries(); 206 incrementNumTombstones(); 207 } 208 209 value_type& FindAndConstruct(const KeyT &Key) { 210 BucketT *TheBucket; 211 if (LookupBucketFor(Key, TheBucket)) 212 return *TheBucket; 213 214 return *InsertIntoBucket(Key, ValueT(), TheBucket); 215 } 216 217 ValueT &operator[](const KeyT &Key) { 218 return FindAndConstruct(Key).second; 219 } 220 221#if LLVM_HAS_RVALUE_REFERENCES 222 value_type& FindAndConstruct(KeyT &&Key) { 223 BucketT *TheBucket; 224 if (LookupBucketFor(Key, TheBucket)) 225 return *TheBucket; 226 227 return *InsertIntoBucket(std::move(Key), ValueT(), TheBucket); 228 } 229 230 ValueT &operator[](KeyT &&Key) { 231 return FindAndConstruct(std::move(Key)).second; 232 } 233#endif 234 235 /// isPointerIntoBucketsArray - Return true if the specified pointer points 236 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or 237 /// value in the DenseMap). 238 bool isPointerIntoBucketsArray(const void *Ptr) const { 239 return Ptr >= getBuckets() && Ptr < getBucketsEnd(); 240 } 241 242 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets 243 /// array. In conjunction with the previous method, this can be used to 244 /// determine whether an insertion caused the DenseMap to reallocate. 245 const void *getPointerIntoBucketsArray() const { return getBuckets(); } 246 247protected: 248 DenseMapBase() {} 249 250 void destroyAll() { 251 if (getNumBuckets() == 0) // Nothing to do. 252 return; 253 254 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); 255 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { 256 if (!KeyInfoT::isEqual(P->first, EmptyKey) && 257 !KeyInfoT::isEqual(P->first, TombstoneKey)) 258 P->second.~ValueT(); 259 P->first.~KeyT(); 260 } 261 262#ifndef NDEBUG 263 memset((void*)getBuckets(), 0x5a, sizeof(BucketT)*getNumBuckets()); 264#endif 265 } 266 267 void initEmpty() { 268 setNumEntries(0); 269 setNumTombstones(0); 270 271 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 && 272 "# initial buckets must be a power of two!"); 273 const KeyT EmptyKey = getEmptyKey(); 274 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B) 275 new (&B->first) KeyT(EmptyKey); 276 } 277 278 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) { 279 initEmpty(); 280 281 // Insert all the old elements. 282 const KeyT EmptyKey = getEmptyKey(); 283 const KeyT TombstoneKey = getTombstoneKey(); 284 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) { 285 if (!KeyInfoT::isEqual(B->first, EmptyKey) && 286 !KeyInfoT::isEqual(B->first, TombstoneKey)) { 287 // Insert the key/value into the new table. 288 BucketT *DestBucket; 289 bool FoundVal = LookupBucketFor(B->first, DestBucket); 290 (void)FoundVal; // silence warning. 291 assert(!FoundVal && "Key already in new map?"); 292 DestBucket->first = llvm_move(B->first); 293 new (&DestBucket->second) ValueT(llvm_move(B->second)); 294 incrementNumEntries(); 295 296 // Free the value. 297 B->second.~ValueT(); 298 } 299 B->first.~KeyT(); 300 } 301 302#ifndef NDEBUG 303 if (OldBucketsBegin != OldBucketsEnd) 304 memset((void*)OldBucketsBegin, 0x5a, 305 sizeof(BucketT) * (OldBucketsEnd - OldBucketsBegin)); 306#endif 307 } 308 309 template <typename OtherBaseT> 310 void copyFrom(const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT>& other) { 311 assert(getNumBuckets() == other.getNumBuckets()); 312 313 setNumEntries(other.getNumEntries()); 314 setNumTombstones(other.getNumTombstones()); 315 316 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value) 317 memcpy(getBuckets(), other.getBuckets(), 318 getNumBuckets() * sizeof(BucketT)); 319 else 320 for (size_t i = 0; i < getNumBuckets(); ++i) { 321 new (&getBuckets()[i].first) KeyT(other.getBuckets()[i].first); 322 if (!KeyInfoT::isEqual(getBuckets()[i].first, getEmptyKey()) && 323 !KeyInfoT::isEqual(getBuckets()[i].first, getTombstoneKey())) 324 new (&getBuckets()[i].second) ValueT(other.getBuckets()[i].second); 325 } 326 } 327 328 void swap(DenseMapBase& RHS) { 329 std::swap(getNumEntries(), RHS.getNumEntries()); 330 std::swap(getNumTombstones(), RHS.getNumTombstones()); 331 } 332 333 static unsigned getHashValue(const KeyT &Val) { 334 return KeyInfoT::getHashValue(Val); 335 } 336 template<typename LookupKeyT> 337 static unsigned getHashValue(const LookupKeyT &Val) { 338 return KeyInfoT::getHashValue(Val); 339 } 340 static const KeyT getEmptyKey() { 341 return KeyInfoT::getEmptyKey(); 342 } 343 static const KeyT getTombstoneKey() { 344 return KeyInfoT::getTombstoneKey(); 345 } 346 347private: 348 unsigned getNumEntries() const { 349 return static_cast<const DerivedT *>(this)->getNumEntries(); 350 } 351 void setNumEntries(unsigned Num) { 352 static_cast<DerivedT *>(this)->setNumEntries(Num); 353 } 354 void incrementNumEntries() { 355 setNumEntries(getNumEntries() + 1); 356 } 357 void decrementNumEntries() { 358 setNumEntries(getNumEntries() - 1); 359 } 360 unsigned getNumTombstones() const { 361 return static_cast<const DerivedT *>(this)->getNumTombstones(); 362 } 363 void setNumTombstones(unsigned Num) { 364 static_cast<DerivedT *>(this)->setNumTombstones(Num); 365 } 366 void incrementNumTombstones() { 367 setNumTombstones(getNumTombstones() + 1); 368 } 369 void decrementNumTombstones() { 370 setNumTombstones(getNumTombstones() - 1); 371 } 372 const BucketT *getBuckets() const { 373 return static_cast<const DerivedT *>(this)->getBuckets(); 374 } 375 BucketT *getBuckets() { 376 return static_cast<DerivedT *>(this)->getBuckets(); 377 } 378 unsigned getNumBuckets() const { 379 return static_cast<const DerivedT *>(this)->getNumBuckets(); 380 } 381 BucketT *getBucketsEnd() { 382 return getBuckets() + getNumBuckets(); 383 } 384 const BucketT *getBucketsEnd() const { 385 return getBuckets() + getNumBuckets(); 386 } 387 388 void grow(unsigned AtLeast) { 389 static_cast<DerivedT *>(this)->grow(AtLeast); 390 } 391 392 void shrink_and_clear() { 393 static_cast<DerivedT *>(this)->shrink_and_clear(); 394 } 395 396 397 BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value, 398 BucketT *TheBucket) { 399 TheBucket = InsertIntoBucketImpl(Key, TheBucket); 400 401 TheBucket->first = Key; 402 new (&TheBucket->second) ValueT(Value); 403 return TheBucket; 404 } 405 406#if LLVM_HAS_RVALUE_REFERENCES 407 BucketT *InsertIntoBucket(const KeyT &Key, ValueT &&Value, 408 BucketT *TheBucket) { 409 TheBucket = InsertIntoBucketImpl(Key, TheBucket); 410 411 TheBucket->first = Key; 412 new (&TheBucket->second) ValueT(std::move(Value)); 413 return TheBucket; 414 } 415 416 BucketT *InsertIntoBucket(KeyT &&Key, ValueT &&Value, BucketT *TheBucket) { 417 TheBucket = InsertIntoBucketImpl(Key, TheBucket); 418 419 TheBucket->first = std::move(Key); 420 new (&TheBucket->second) ValueT(std::move(Value)); 421 return TheBucket; 422 } 423#endif 424 425 BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) { 426 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of 427 // the buckets are empty (meaning that many are filled with tombstones), 428 // grow the table. 429 // 430 // The later case is tricky. For example, if we had one empty bucket with 431 // tons of tombstones, failing lookups (e.g. for insertion) would have to 432 // probe almost the entire table until it found the empty bucket. If the 433 // table completely filled with tombstones, no lookup would ever succeed, 434 // causing infinite loops in lookup. 435 unsigned NewNumEntries = getNumEntries() + 1; 436 unsigned NumBuckets = getNumBuckets(); 437 if (NewNumEntries*4 >= NumBuckets*3) { 438 this->grow(NumBuckets * 2); 439 LookupBucketFor(Key, TheBucket); 440 NumBuckets = getNumBuckets(); 441 } else if (NumBuckets-(NewNumEntries+getNumTombstones()) <= NumBuckets/8) { 442 this->grow(NumBuckets); 443 LookupBucketFor(Key, TheBucket); 444 } 445 assert(TheBucket); 446 447 // Only update the state after we've grown our bucket space appropriately 448 // so that when growing buckets we have self-consistent entry count. 449 incrementNumEntries(); 450 451 // If we are writing over a tombstone, remember this. 452 const KeyT EmptyKey = getEmptyKey(); 453 if (!KeyInfoT::isEqual(TheBucket->first, EmptyKey)) 454 decrementNumTombstones(); 455 456 return TheBucket; 457 } 458 459 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in 460 /// FoundBucket. If the bucket contains the key and a value, this returns 461 /// true, otherwise it returns a bucket with an empty marker or tombstone and 462 /// returns false. 463 template<typename LookupKeyT> 464 bool LookupBucketFor(const LookupKeyT &Val, 465 const BucketT *&FoundBucket) const { 466 const BucketT *BucketsPtr = getBuckets(); 467 const unsigned NumBuckets = getNumBuckets(); 468 469 if (NumBuckets == 0) { 470 FoundBucket = 0; 471 return false; 472 } 473 474 // FoundTombstone - Keep track of whether we find a tombstone while probing. 475 const BucketT *FoundTombstone = 0; 476 const KeyT EmptyKey = getEmptyKey(); 477 const KeyT TombstoneKey = getTombstoneKey(); 478 assert(!KeyInfoT::isEqual(Val, EmptyKey) && 479 !KeyInfoT::isEqual(Val, TombstoneKey) && 480 "Empty/Tombstone value shouldn't be inserted into map!"); 481 482 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1); 483 unsigned ProbeAmt = 1; 484 while (1) { 485 const BucketT *ThisBucket = BucketsPtr + BucketNo; 486 // Found Val's bucket? If so, return it. 487 if (KeyInfoT::isEqual(Val, ThisBucket->first)) { 488 FoundBucket = ThisBucket; 489 return true; 490 } 491 492 // If we found an empty bucket, the key doesn't exist in the set. 493 // Insert it and return the default value. 494 if (KeyInfoT::isEqual(ThisBucket->first, EmptyKey)) { 495 // If we've already seen a tombstone while probing, fill it in instead 496 // of the empty bucket we eventually probed to. 497 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket; 498 return false; 499 } 500 501 // If this is a tombstone, remember it. If Val ends up not in the map, we 502 // prefer to return it than something that would require more probing. 503 if (KeyInfoT::isEqual(ThisBucket->first, TombstoneKey) && !FoundTombstone) 504 FoundTombstone = ThisBucket; // Remember the first tombstone found. 505 506 // Otherwise, it's a hash collision or a tombstone, continue quadratic 507 // probing. 508 BucketNo += ProbeAmt++; 509 BucketNo &= (NumBuckets-1); 510 } 511 } 512 513 template <typename LookupKeyT> 514 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) { 515 const BucketT *ConstFoundBucket; 516 bool Result = const_cast<const DenseMapBase *>(this) 517 ->LookupBucketFor(Val, ConstFoundBucket); 518 FoundBucket = const_cast<BucketT *>(ConstFoundBucket); 519 return Result; 520 } 521 522public: 523 /// Return the approximate size (in bytes) of the actual map. 524 /// This is just the raw memory used by DenseMap. 525 /// If entries are pointers to objects, the size of the referenced objects 526 /// are not included. 527 size_t getMemorySize() const { 528 return getNumBuckets() * sizeof(BucketT); 529 } 530}; 531 532template<typename KeyT, typename ValueT, 533 typename KeyInfoT = DenseMapInfo<KeyT> > 534class DenseMap 535 : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT>, 536 KeyT, ValueT, KeyInfoT> { 537 // Lift some types from the dependent base class into this class for 538 // simplicity of referring to them. 539 typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT> BaseT; 540 typedef typename BaseT::BucketT BucketT; 541 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT>; 542 543 BucketT *Buckets; 544 unsigned NumEntries; 545 unsigned NumTombstones; 546 unsigned NumBuckets; 547 548public: 549 explicit DenseMap(unsigned NumInitBuckets = 0) { 550 init(NumInitBuckets); 551 } 552 553 DenseMap(const DenseMap &other) : BaseT() { 554 init(0); 555 copyFrom(other); 556 } 557 558#if LLVM_HAS_RVALUE_REFERENCES 559 DenseMap(DenseMap &&other) : BaseT() { 560 init(0); 561 swap(other); 562 } 563#endif 564 565 template<typename InputIt> 566 DenseMap(const InputIt &I, const InputIt &E) { 567 init(NextPowerOf2(std::distance(I, E))); 568 this->insert(I, E); 569 } 570 571 ~DenseMap() { 572 this->destroyAll(); 573 operator delete(Buckets); 574 } 575 576 void swap(DenseMap& RHS) { 577 std::swap(Buckets, RHS.Buckets); 578 std::swap(NumEntries, RHS.NumEntries); 579 std::swap(NumTombstones, RHS.NumTombstones); 580 std::swap(NumBuckets, RHS.NumBuckets); 581 } 582 583 DenseMap& operator=(const DenseMap& other) { 584 copyFrom(other); 585 return *this; 586 } 587 588#if LLVM_HAS_RVALUE_REFERENCES 589 DenseMap& operator=(DenseMap &&other) { 590 this->destroyAll(); 591 operator delete(Buckets); 592 init(0); 593 swap(other); 594 return *this; 595 } 596#endif 597 598 void copyFrom(const DenseMap& other) { 599 this->destroyAll(); 600 operator delete(Buckets); 601 if (allocateBuckets(other.NumBuckets)) { 602 this->BaseT::copyFrom(other); 603 } else { 604 NumEntries = 0; 605 NumTombstones = 0; 606 } 607 } 608 609 void init(unsigned InitBuckets) { 610 if (allocateBuckets(InitBuckets)) { 611 this->BaseT::initEmpty(); 612 } else { 613 NumEntries = 0; 614 NumTombstones = 0; 615 } 616 } 617 618 void grow(unsigned AtLeast) { 619 unsigned OldNumBuckets = NumBuckets; 620 BucketT *OldBuckets = Buckets; 621 622 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1)))); 623 assert(Buckets); 624 if (!OldBuckets) { 625 this->BaseT::initEmpty(); 626 return; 627 } 628 629 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets); 630 631 // Free the old table. 632 operator delete(OldBuckets); 633 } 634 635 void shrink_and_clear() { 636 unsigned OldNumEntries = NumEntries; 637 this->destroyAll(); 638 639 // Reduce the number of buckets. 640 unsigned NewNumBuckets = 0; 641 if (OldNumEntries) 642 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1)); 643 if (NewNumBuckets == NumBuckets) { 644 this->BaseT::initEmpty(); 645 return; 646 } 647 648 operator delete(Buckets); 649 init(NewNumBuckets); 650 } 651 652private: 653 unsigned getNumEntries() const { 654 return NumEntries; 655 } 656 void setNumEntries(unsigned Num) { 657 NumEntries = Num; 658 } 659 660 unsigned getNumTombstones() const { 661 return NumTombstones; 662 } 663 void setNumTombstones(unsigned Num) { 664 NumTombstones = Num; 665 } 666 667 BucketT *getBuckets() const { 668 return Buckets; 669 } 670 671 unsigned getNumBuckets() const { 672 return NumBuckets; 673 } 674 675 bool allocateBuckets(unsigned Num) { 676 NumBuckets = Num; 677 if (NumBuckets == 0) { 678 Buckets = 0; 679 return false; 680 } 681 682 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets)); 683 return true; 684 } 685}; 686 687template<typename KeyT, typename ValueT, 688 unsigned InlineBuckets = 4, 689 typename KeyInfoT = DenseMapInfo<KeyT> > 690class SmallDenseMap 691 : public DenseMapBase<SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT>, 692 KeyT, ValueT, KeyInfoT> { 693 // Lift some types from the dependent base class into this class for 694 // simplicity of referring to them. 695 typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT> BaseT; 696 typedef typename BaseT::BucketT BucketT; 697 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT>; 698 699 unsigned Small : 1; 700 unsigned NumEntries : 31; 701 unsigned NumTombstones; 702 703 struct LargeRep { 704 BucketT *Buckets; 705 unsigned NumBuckets; 706 }; 707 708 /// A "union" of an inline bucket array and the struct representing 709 /// a large bucket. This union will be discriminated by the 'Small' bit. 710 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage; 711 712public: 713 explicit SmallDenseMap(unsigned NumInitBuckets = 0) { 714 init(NumInitBuckets); 715 } 716 717 SmallDenseMap(const SmallDenseMap &other) : BaseT() { 718 init(0); 719 copyFrom(other); 720 } 721 722#if LLVM_HAS_RVALUE_REFERENCES 723 SmallDenseMap(SmallDenseMap &&other) : BaseT() { 724 init(0); 725 swap(other); 726 } 727#endif 728 729 template<typename InputIt> 730 SmallDenseMap(const InputIt &I, const InputIt &E) { 731 init(NextPowerOf2(std::distance(I, E))); 732 this->insert(I, E); 733 } 734 735 ~SmallDenseMap() { 736 this->destroyAll(); 737 deallocateBuckets(); 738 } 739 740 void swap(SmallDenseMap& RHS) { 741 unsigned TmpNumEntries = RHS.NumEntries; 742 RHS.NumEntries = NumEntries; 743 NumEntries = TmpNumEntries; 744 std::swap(NumTombstones, RHS.NumTombstones); 745 746 const KeyT EmptyKey = this->getEmptyKey(); 747 const KeyT TombstoneKey = this->getTombstoneKey(); 748 if (Small && RHS.Small) { 749 // If we're swapping inline bucket arrays, we have to cope with some of 750 // the tricky bits of DenseMap's storage system: the buckets are not 751 // fully initialized. Thus we swap every key, but we may have 752 // a one-directional move of the value. 753 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 754 BucketT *LHSB = &getInlineBuckets()[i], 755 *RHSB = &RHS.getInlineBuckets()[i]; 756 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->first, EmptyKey) && 757 !KeyInfoT::isEqual(LHSB->first, TombstoneKey)); 758 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->first, EmptyKey) && 759 !KeyInfoT::isEqual(RHSB->first, TombstoneKey)); 760 if (hasLHSValue && hasRHSValue) { 761 // Swap together if we can... 762 std::swap(*LHSB, *RHSB); 763 continue; 764 } 765 // Swap separately and handle any assymetry. 766 std::swap(LHSB->first, RHSB->first); 767 if (hasLHSValue) { 768 new (&RHSB->second) ValueT(llvm_move(LHSB->second)); 769 LHSB->second.~ValueT(); 770 } else if (hasRHSValue) { 771 new (&LHSB->second) ValueT(llvm_move(RHSB->second)); 772 RHSB->second.~ValueT(); 773 } 774 } 775 return; 776 } 777 if (!Small && !RHS.Small) { 778 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets); 779 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets); 780 return; 781 } 782 783 SmallDenseMap &SmallSide = Small ? *this : RHS; 784 SmallDenseMap &LargeSide = Small ? RHS : *this; 785 786 // First stash the large side's rep and move the small side across. 787 LargeRep TmpRep = llvm_move(*LargeSide.getLargeRep()); 788 LargeSide.getLargeRep()->~LargeRep(); 789 LargeSide.Small = true; 790 // This is similar to the standard move-from-old-buckets, but the bucket 791 // count hasn't actually rotated in this case. So we have to carefully 792 // move construct the keys and values into their new locations, but there 793 // is no need to re-hash things. 794 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 795 BucketT *NewB = &LargeSide.getInlineBuckets()[i], 796 *OldB = &SmallSide.getInlineBuckets()[i]; 797 new (&NewB->first) KeyT(llvm_move(OldB->first)); 798 OldB->first.~KeyT(); 799 if (!KeyInfoT::isEqual(NewB->first, EmptyKey) && 800 !KeyInfoT::isEqual(NewB->first, TombstoneKey)) { 801 new (&NewB->second) ValueT(llvm_move(OldB->second)); 802 OldB->second.~ValueT(); 803 } 804 } 805 806 // The hard part of moving the small buckets across is done, just move 807 // the TmpRep into its new home. 808 SmallSide.Small = false; 809 new (SmallSide.getLargeRep()) LargeRep(llvm_move(TmpRep)); 810 } 811 812 SmallDenseMap& operator=(const SmallDenseMap& other) { 813 copyFrom(other); 814 return *this; 815 } 816 817#if LLVM_HAS_RVALUE_REFERENCES 818 SmallDenseMap& operator=(SmallDenseMap &&other) { 819 this->destroyAll(); 820 deallocateBuckets(); 821 init(0); 822 swap(other); 823 return *this; 824 } 825#endif 826 827 void copyFrom(const SmallDenseMap& other) { 828 this->destroyAll(); 829 deallocateBuckets(); 830 Small = true; 831 if (other.getNumBuckets() > InlineBuckets) { 832 Small = false; 833 allocateBuckets(other.getNumBuckets()); 834 } 835 this->BaseT::copyFrom(other); 836 } 837 838 void init(unsigned InitBuckets) { 839 Small = true; 840 if (InitBuckets > InlineBuckets) { 841 Small = false; 842 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets)); 843 } 844 this->BaseT::initEmpty(); 845 } 846 847 void grow(unsigned AtLeast) { 848 if (AtLeast >= InlineBuckets) 849 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1)); 850 851 if (Small) { 852 if (AtLeast < InlineBuckets) 853 return; // Nothing to do. 854 855 // First move the inline buckets into a temporary storage. 856 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage; 857 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer); 858 BucketT *TmpEnd = TmpBegin; 859 860 // Loop over the buckets, moving non-empty, non-tombstones into the 861 // temporary storage. Have the loop move the TmpEnd forward as it goes. 862 const KeyT EmptyKey = this->getEmptyKey(); 863 const KeyT TombstoneKey = this->getTombstoneKey(); 864 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) { 865 if (!KeyInfoT::isEqual(P->first, EmptyKey) && 866 !KeyInfoT::isEqual(P->first, TombstoneKey)) { 867 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets && 868 "Too many inline buckets!"); 869 new (&TmpEnd->first) KeyT(llvm_move(P->first)); 870 new (&TmpEnd->second) ValueT(llvm_move(P->second)); 871 ++TmpEnd; 872 P->second.~ValueT(); 873 } 874 P->first.~KeyT(); 875 } 876 877 // Now make this map use the large rep, and move all the entries back 878 // into it. 879 Small = false; 880 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 881 this->moveFromOldBuckets(TmpBegin, TmpEnd); 882 return; 883 } 884 885 LargeRep OldRep = llvm_move(*getLargeRep()); 886 getLargeRep()->~LargeRep(); 887 if (AtLeast <= InlineBuckets) { 888 Small = true; 889 } else { 890 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 891 } 892 893 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets); 894 895 // Free the old table. 896 operator delete(OldRep.Buckets); 897 } 898 899 void shrink_and_clear() { 900 unsigned OldSize = this->size(); 901 this->destroyAll(); 902 903 // Reduce the number of buckets. 904 unsigned NewNumBuckets = 0; 905 if (OldSize) { 906 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1); 907 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u) 908 NewNumBuckets = 64; 909 } 910 if ((Small && NewNumBuckets <= InlineBuckets) || 911 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) { 912 this->BaseT::initEmpty(); 913 return; 914 } 915 916 deallocateBuckets(); 917 init(NewNumBuckets); 918 } 919 920private: 921 unsigned getNumEntries() const { 922 return NumEntries; 923 } 924 void setNumEntries(unsigned Num) { 925 assert(Num < INT_MAX && "Cannot support more than INT_MAX entries"); 926 NumEntries = Num; 927 } 928 929 unsigned getNumTombstones() const { 930 return NumTombstones; 931 } 932 void setNumTombstones(unsigned Num) { 933 NumTombstones = Num; 934 } 935 936 const BucketT *getInlineBuckets() const { 937 assert(Small); 938 // Note that this cast does not violate aliasing rules as we assert that 939 // the memory's dynamic type is the small, inline bucket buffer, and the 940 // 'storage.buffer' static type is 'char *'. 941 return reinterpret_cast<const BucketT *>(storage.buffer); 942 } 943 BucketT *getInlineBuckets() { 944 return const_cast<BucketT *>( 945 const_cast<const SmallDenseMap *>(this)->getInlineBuckets()); 946 } 947 const LargeRep *getLargeRep() const { 948 assert(!Small); 949 // Note, same rule about aliasing as with getInlineBuckets. 950 return reinterpret_cast<const LargeRep *>(storage.buffer); 951 } 952 LargeRep *getLargeRep() { 953 return const_cast<LargeRep *>( 954 const_cast<const SmallDenseMap *>(this)->getLargeRep()); 955 } 956 957 const BucketT *getBuckets() const { 958 return Small ? getInlineBuckets() : getLargeRep()->Buckets; 959 } 960 BucketT *getBuckets() { 961 return const_cast<BucketT *>( 962 const_cast<const SmallDenseMap *>(this)->getBuckets()); 963 } 964 unsigned getNumBuckets() const { 965 return Small ? InlineBuckets : getLargeRep()->NumBuckets; 966 } 967 968 void deallocateBuckets() { 969 if (Small) 970 return; 971 972 operator delete(getLargeRep()->Buckets); 973 getLargeRep()->~LargeRep(); 974 } 975 976 LargeRep allocateBuckets(unsigned Num) { 977 assert(Num > InlineBuckets && "Must allocate more buckets than are inline"); 978 LargeRep Rep = { 979 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num 980 }; 981 return Rep; 982 } 983}; 984 985template<typename KeyT, typename ValueT, 986 typename KeyInfoT, bool IsConst> 987class DenseMapIterator { 988 typedef std::pair<KeyT, ValueT> Bucket; 989 typedef DenseMapIterator<KeyT, ValueT, 990 KeyInfoT, true> ConstIterator; 991 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, true>; 992public: 993 typedef ptrdiff_t difference_type; 994 typedef typename conditional<IsConst, const Bucket, Bucket>::type value_type; 995 typedef value_type *pointer; 996 typedef value_type &reference; 997 typedef std::forward_iterator_tag iterator_category; 998private: 999 pointer Ptr, End; 1000public: 1001 DenseMapIterator() : Ptr(0), End(0) {} 1002 1003 DenseMapIterator(pointer Pos, pointer E, bool NoAdvance = false) 1004 : Ptr(Pos), End(E) { 1005 if (!NoAdvance) AdvancePastEmptyBuckets(); 1006 } 1007 1008 // If IsConst is true this is a converting constructor from iterator to 1009 // const_iterator and the default copy constructor is used. 1010 // Otherwise this is a copy constructor for iterator. 1011 DenseMapIterator(const DenseMapIterator<KeyT, ValueT, 1012 KeyInfoT, false>& I) 1013 : Ptr(I.Ptr), End(I.End) {} 1014 1015 reference operator*() const { 1016 return *Ptr; 1017 } 1018 pointer operator->() const { 1019 return Ptr; 1020 } 1021 1022 bool operator==(const ConstIterator &RHS) const { 1023 return Ptr == RHS.operator->(); 1024 } 1025 bool operator!=(const ConstIterator &RHS) const { 1026 return Ptr != RHS.operator->(); 1027 } 1028 1029 inline DenseMapIterator& operator++() { // Preincrement 1030 ++Ptr; 1031 AdvancePastEmptyBuckets(); 1032 return *this; 1033 } 1034 DenseMapIterator operator++(int) { // Postincrement 1035 DenseMapIterator tmp = *this; ++*this; return tmp; 1036 } 1037 1038private: 1039 void AdvancePastEmptyBuckets() { 1040 const KeyT Empty = KeyInfoT::getEmptyKey(); 1041 const KeyT Tombstone = KeyInfoT::getTombstoneKey(); 1042 1043 while (Ptr != End && 1044 (KeyInfoT::isEqual(Ptr->first, Empty) || 1045 KeyInfoT::isEqual(Ptr->first, Tombstone))) 1046 ++Ptr; 1047 } 1048}; 1049 1050template<typename KeyT, typename ValueT, typename KeyInfoT> 1051static inline size_t 1052capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) { 1053 return X.getMemorySize(); 1054} 1055 1056} // end namespace llvm 1057 1058#endif 1059