DenseMap.h revision 9e8eafa0f0ad36c3e4397e97b67b8245b04ba618
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 empty() const { return getNumEntries() == 0; } 68 unsigned size() const { return getNumEntries(); } 69 70 /// Grow the densemap so that it has at least Size buckets. Does not shrink 71 void resize(size_t Size) { 72 if (Size > getNumBuckets()) 73 grow(Size); 74 } 75 76 void clear() { 77 if (getNumEntries() == 0 && getNumTombstones() == 0) return; 78 79 // If the capacity of the array is huge, and the # elements used is small, 80 // shrink the array. 81 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) { 82 shrink_and_clear(); 83 return; 84 } 85 86 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); 87 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { 88 if (!KeyInfoT::isEqual(P->first, EmptyKey)) { 89 if (!KeyInfoT::isEqual(P->first, TombstoneKey)) { 90 P->second.~ValueT(); 91 decrementNumEntries(); 92 } 93 P->first = EmptyKey; 94 } 95 } 96 assert(getNumEntries() == 0 && "Node count imbalance!"); 97 setNumTombstones(0); 98 } 99 100 /// count - Return true if the specified key is in the map. 101 bool count(const KeyT &Val) const { 102 const BucketT *TheBucket; 103 return LookupBucketFor(Val, TheBucket); 104 } 105 106 iterator find(const KeyT &Val) { 107 BucketT *TheBucket; 108 if (LookupBucketFor(Val, TheBucket)) 109 return iterator(TheBucket, getBucketsEnd(), true); 110 return end(); 111 } 112 const_iterator find(const KeyT &Val) const { 113 const BucketT *TheBucket; 114 if (LookupBucketFor(Val, TheBucket)) 115 return const_iterator(TheBucket, getBucketsEnd(), true); 116 return end(); 117 } 118 119 /// Alternate version of find() which allows a different, and possibly 120 /// less expensive, key type. 121 /// The DenseMapInfo is responsible for supplying methods 122 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key 123 /// type used. 124 template<class LookupKeyT> 125 iterator find_as(const LookupKeyT &Val) { 126 BucketT *TheBucket; 127 if (LookupBucketFor(Val, TheBucket)) 128 return iterator(TheBucket, getBucketsEnd(), true); 129 return end(); 130 } 131 template<class LookupKeyT> 132 const_iterator find_as(const LookupKeyT &Val) const { 133 const BucketT *TheBucket; 134 if (LookupBucketFor(Val, TheBucket)) 135 return const_iterator(TheBucket, getBucketsEnd(), true); 136 return end(); 137 } 138 139 /// lookup - Return the entry for the specified key, or a default 140 /// constructed value if no such entry exists. 141 ValueT lookup(const KeyT &Val) const { 142 const BucketT *TheBucket; 143 if (LookupBucketFor(Val, TheBucket)) 144 return TheBucket->second; 145 return ValueT(); 146 } 147 148 // Inserts key,value pair into the map if the key isn't already in the map. 149 // If the key is already in the map, it returns false and doesn't update the 150 // value. 151 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) { 152 BucketT *TheBucket; 153 if (LookupBucketFor(KV.first, TheBucket)) 154 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), 155 false); // Already in map. 156 157 // Otherwise, insert the new element. 158 TheBucket = InsertIntoBucket(KV.first, KV.second, TheBucket); 159 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true); 160 } 161 162#if LLVM_HAS_RVALUE_REFERENCES 163 // Inserts key,value pair into the map if the key isn't already in the map. 164 // If the key is already in the map, it returns false and doesn't update the 165 // value. 166 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) { 167 BucketT *TheBucket; 168 if (LookupBucketFor(KV.first, TheBucket)) 169 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), 170 false); // Already in map. 171 172 // Otherwise, insert the new element. 173 TheBucket = InsertIntoBucket(std::move(KV.first), 174 std::move(KV.second), 175 TheBucket); 176 return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true); 177 } 178#endif 179 180 /// insert - Range insertion of pairs. 181 template<typename InputIt> 182 void insert(InputIt I, InputIt E) { 183 for (; I != E; ++I) 184 insert(*I); 185 } 186 187 188 bool erase(const KeyT &Val) { 189 BucketT *TheBucket; 190 if (!LookupBucketFor(Val, TheBucket)) 191 return false; // not in map. 192 193 TheBucket->second.~ValueT(); 194 TheBucket->first = getTombstoneKey(); 195 decrementNumEntries(); 196 incrementNumTombstones(); 197 return true; 198 } 199 void erase(iterator I) { 200 BucketT *TheBucket = &*I; 201 TheBucket->second.~ValueT(); 202 TheBucket->first = getTombstoneKey(); 203 decrementNumEntries(); 204 incrementNumTombstones(); 205 } 206 207 value_type& FindAndConstruct(const KeyT &Key) { 208 BucketT *TheBucket; 209 if (LookupBucketFor(Key, TheBucket)) 210 return *TheBucket; 211 212 return *InsertIntoBucket(Key, ValueT(), TheBucket); 213 } 214 215 ValueT &operator[](const KeyT &Key) { 216 return FindAndConstruct(Key).second; 217 } 218 219#if LLVM_HAS_RVALUE_REFERENCES 220 value_type& FindAndConstruct(KeyT &&Key) { 221 BucketT *TheBucket; 222 if (LookupBucketFor(Key, TheBucket)) 223 return *TheBucket; 224 225 return *InsertIntoBucket(std::move(Key), ValueT(), TheBucket); 226 } 227 228 ValueT &operator[](KeyT &&Key) { 229 return FindAndConstruct(std::move(Key)).second; 230 } 231#endif 232 233 /// isPointerIntoBucketsArray - Return true if the specified pointer points 234 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or 235 /// value in the DenseMap). 236 bool isPointerIntoBucketsArray(const void *Ptr) const { 237 return Ptr >= getBuckets() && Ptr < getBucketsEnd(); 238 } 239 240 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets 241 /// array. In conjunction with the previous method, this can be used to 242 /// determine whether an insertion caused the DenseMap to reallocate. 243 const void *getPointerIntoBucketsArray() const { return getBuckets(); } 244 245protected: 246 DenseMapBase() {} 247 248 void destroyAll() { 249 if (getNumBuckets() == 0) // Nothing to do. 250 return; 251 252 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); 253 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { 254 if (!KeyInfoT::isEqual(P->first, EmptyKey) && 255 !KeyInfoT::isEqual(P->first, TombstoneKey)) 256 P->second.~ValueT(); 257 P->first.~KeyT(); 258 } 259 260#ifndef NDEBUG 261 memset((void*)getBuckets(), 0x5a, sizeof(BucketT)*getNumBuckets()); 262#endif 263 } 264 265 void initEmpty() { 266 setNumEntries(0); 267 setNumTombstones(0); 268 269 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 && 270 "# initial buckets must be a power of two!"); 271 const KeyT EmptyKey = getEmptyKey(); 272 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B) 273 new (&B->first) KeyT(EmptyKey); 274 } 275 276 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) { 277 initEmpty(); 278 279 // Insert all the old elements. 280 const KeyT EmptyKey = getEmptyKey(); 281 const KeyT TombstoneKey = getTombstoneKey(); 282 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) { 283 if (!KeyInfoT::isEqual(B->first, EmptyKey) && 284 !KeyInfoT::isEqual(B->first, TombstoneKey)) { 285 // Insert the key/value into the new table. 286 BucketT *DestBucket; 287 bool FoundVal = LookupBucketFor(B->first, DestBucket); 288 (void)FoundVal; // silence warning. 289 assert(!FoundVal && "Key already in new map?"); 290 DestBucket->first = llvm_move(B->first); 291 new (&DestBucket->second) ValueT(llvm_move(B->second)); 292 incrementNumEntries(); 293 294 // Free the value. 295 B->second.~ValueT(); 296 } 297 B->first.~KeyT(); 298 } 299 300#ifndef NDEBUG 301 if (OldBucketsBegin != OldBucketsEnd) 302 memset((void*)OldBucketsBegin, 0x5a, 303 sizeof(BucketT) * (OldBucketsEnd - OldBucketsBegin)); 304#endif 305 } 306 307 template <typename OtherBaseT> 308 void copyFrom(const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT>& other) { 309 assert(getNumBuckets() == other.getNumBuckets()); 310 311 setNumEntries(other.getNumEntries()); 312 setNumTombstones(other.getNumTombstones()); 313 314 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value) 315 memcpy(getBuckets(), other.getBuckets(), 316 getNumBuckets() * sizeof(BucketT)); 317 else 318 for (size_t i = 0; i < getNumBuckets(); ++i) { 319 new (&getBuckets()[i].first) KeyT(other.getBuckets()[i].first); 320 if (!KeyInfoT::isEqual(getBuckets()[i].first, getEmptyKey()) && 321 !KeyInfoT::isEqual(getBuckets()[i].first, getTombstoneKey())) 322 new (&getBuckets()[i].second) ValueT(other.getBuckets()[i].second); 323 } 324 } 325 326 void swap(DenseMapBase& RHS) { 327 std::swap(getNumEntries(), RHS.getNumEntries()); 328 std::swap(getNumTombstones(), RHS.getNumTombstones()); 329 } 330 331 static unsigned getHashValue(const KeyT &Val) { 332 return KeyInfoT::getHashValue(Val); 333 } 334 template<typename LookupKeyT> 335 static unsigned getHashValue(const LookupKeyT &Val) { 336 return KeyInfoT::getHashValue(Val); 337 } 338 static const KeyT getEmptyKey() { 339 return KeyInfoT::getEmptyKey(); 340 } 341 static const KeyT getTombstoneKey() { 342 return KeyInfoT::getTombstoneKey(); 343 } 344 345private: 346 unsigned getNumEntries() const { 347 return static_cast<const DerivedT *>(this)->getNumEntries(); 348 } 349 void setNumEntries(unsigned Num) { 350 static_cast<DerivedT *>(this)->setNumEntries(Num); 351 } 352 void incrementNumEntries() { 353 setNumEntries(getNumEntries() + 1); 354 } 355 void decrementNumEntries() { 356 setNumEntries(getNumEntries() - 1); 357 } 358 unsigned getNumTombstones() const { 359 return static_cast<const DerivedT *>(this)->getNumTombstones(); 360 } 361 void setNumTombstones(unsigned Num) { 362 static_cast<DerivedT *>(this)->setNumTombstones(Num); 363 } 364 void incrementNumTombstones() { 365 setNumTombstones(getNumTombstones() + 1); 366 } 367 void decrementNumTombstones() { 368 setNumTombstones(getNumTombstones() - 1); 369 } 370 const BucketT *getBuckets() const { 371 return static_cast<const DerivedT *>(this)->getBuckets(); 372 } 373 BucketT *getBuckets() { 374 return static_cast<DerivedT *>(this)->getBuckets(); 375 } 376 unsigned getNumBuckets() const { 377 return static_cast<const DerivedT *>(this)->getNumBuckets(); 378 } 379 BucketT *getBucketsEnd() { 380 return getBuckets() + getNumBuckets(); 381 } 382 const BucketT *getBucketsEnd() const { 383 return getBuckets() + getNumBuckets(); 384 } 385 386 void grow(unsigned AtLeast) { 387 static_cast<DerivedT *>(this)->grow(AtLeast); 388 } 389 390 void shrink_and_clear() { 391 static_cast<DerivedT *>(this)->shrink_and_clear(); 392 } 393 394 395 BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value, 396 BucketT *TheBucket) { 397 TheBucket = InsertIntoBucketImpl(Key, TheBucket); 398 399 TheBucket->first = Key; 400 new (&TheBucket->second) ValueT(Value); 401 return TheBucket; 402 } 403 404#if LLVM_HAS_RVALUE_REFERENCES 405 BucketT *InsertIntoBucket(const KeyT &Key, ValueT &&Value, 406 BucketT *TheBucket) { 407 TheBucket = InsertIntoBucketImpl(Key, TheBucket); 408 409 TheBucket->first = Key; 410 new (&TheBucket->second) ValueT(std::move(Value)); 411 return TheBucket; 412 } 413 414 BucketT *InsertIntoBucket(KeyT &&Key, ValueT &&Value, BucketT *TheBucket) { 415 TheBucket = InsertIntoBucketImpl(Key, TheBucket); 416 417 TheBucket->first = std::move(Key); 418 new (&TheBucket->second) ValueT(std::move(Value)); 419 return TheBucket; 420 } 421#endif 422 423 BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) { 424 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of 425 // the buckets are empty (meaning that many are filled with tombstones), 426 // grow the table. 427 // 428 // The later case is tricky. For example, if we had one empty bucket with 429 // tons of tombstones, failing lookups (e.g. for insertion) would have to 430 // probe almost the entire table until it found the empty bucket. If the 431 // table completely filled with tombstones, no lookup would ever succeed, 432 // causing infinite loops in lookup. 433 unsigned NewNumEntries = getNumEntries() + 1; 434 unsigned NumBuckets = getNumBuckets(); 435 if (NewNumEntries*4 >= NumBuckets*3) { 436 this->grow(NumBuckets * 2); 437 LookupBucketFor(Key, TheBucket); 438 NumBuckets = getNumBuckets(); 439 } 440 if (NumBuckets-(NewNumEntries+getNumTombstones()) <= NumBuckets/8) { 441 this->grow(NumBuckets * 2); 442 LookupBucketFor(Key, TheBucket); 443 } 444 assert(TheBucket); 445 446 // Only update the state after we've grown our bucket space appropriately 447 // so that when growing buckets we have self-consistent entry count. 448 incrementNumEntries(); 449 450 // If we are writing over a tombstone, remember this. 451 const KeyT EmptyKey = getEmptyKey(); 452 if (!KeyInfoT::isEqual(TheBucket->first, EmptyKey)) 453 decrementNumTombstones(); 454 455 return TheBucket; 456 } 457 458 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in 459 /// FoundBucket. If the bucket contains the key and a value, this returns 460 /// true, otherwise it returns a bucket with an empty marker or tombstone and 461 /// returns false. 462 template<typename LookupKeyT> 463 bool LookupBucketFor(const LookupKeyT &Val, 464 const BucketT *&FoundBucket) const { 465 const BucketT *BucketsPtr = getBuckets(); 466 const unsigned NumBuckets = getNumBuckets(); 467 468 if (NumBuckets == 0) { 469 FoundBucket = 0; 470 return false; 471 } 472 473 // FoundTombstone - Keep track of whether we find a tombstone while probing. 474 const BucketT *FoundTombstone = 0; 475 const KeyT EmptyKey = getEmptyKey(); 476 const KeyT TombstoneKey = getTombstoneKey(); 477 assert(!KeyInfoT::isEqual(Val, EmptyKey) && 478 !KeyInfoT::isEqual(Val, TombstoneKey) && 479 "Empty/Tombstone value shouldn't be inserted into map!"); 480 481 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1); 482 unsigned ProbeAmt = 1; 483 while (1) { 484 const BucketT *ThisBucket = BucketsPtr + BucketNo; 485 // Found Val's bucket? If so, return it. 486 if (KeyInfoT::isEqual(Val, ThisBucket->first)) { 487 FoundBucket = ThisBucket; 488 return true; 489 } 490 491 // If we found an empty bucket, the key doesn't exist in the set. 492 // Insert it and return the default value. 493 if (KeyInfoT::isEqual(ThisBucket->first, EmptyKey)) { 494 // If we've already seen a tombstone while probing, fill it in instead 495 // of the empty bucket we eventually probed to. 496 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket; 497 return false; 498 } 499 500 // If this is a tombstone, remember it. If Val ends up not in the map, we 501 // prefer to return it than something that would require more probing. 502 if (KeyInfoT::isEqual(ThisBucket->first, TombstoneKey) && !FoundTombstone) 503 FoundTombstone = ThisBucket; // Remember the first tombstone found. 504 505 // Otherwise, it's a hash collision or a tombstone, continue quadratic 506 // probing. 507 BucketNo += ProbeAmt++; 508 BucketNo &= (NumBuckets-1); 509 } 510 } 511 512 template <typename LookupKeyT> 513 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) { 514 const BucketT *ConstFoundBucket; 515 bool Result = const_cast<const DenseMapBase *>(this) 516 ->LookupBucketFor(Val, ConstFoundBucket); 517 FoundBucket = const_cast<BucketT *>(ConstFoundBucket); 518 return Result; 519 } 520 521public: 522 /// Return the approximate size (in bytes) of the actual map. 523 /// This is just the raw memory used by DenseMap. 524 /// If entries are pointers to objects, the size of the referenced objects 525 /// are not included. 526 size_t getMemorySize() const { 527 return getNumBuckets() * sizeof(BucketT); 528 } 529}; 530 531template<typename KeyT, typename ValueT, 532 typename KeyInfoT = DenseMapInfo<KeyT> > 533class DenseMap 534 : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT>, 535 KeyT, ValueT, KeyInfoT> { 536 // Lift some types from the dependent base class into this class for 537 // simplicity of referring to them. 538 typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT> BaseT; 539 typedef typename BaseT::BucketT BucketT; 540 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT>; 541 542 BucketT *Buckets; 543 unsigned NumEntries; 544 unsigned NumTombstones; 545 unsigned NumBuckets; 546 547public: 548 explicit DenseMap(unsigned NumInitBuckets = 0) { 549 init(NumInitBuckets); 550 } 551 552 DenseMap(const DenseMap &other) : BaseT() { 553 init(0); 554 copyFrom(other); 555 } 556 557#if LLVM_HAS_RVALUE_REFERENCES 558 DenseMap(DenseMap &&other) : BaseT() { 559 init(0); 560 swap(other); 561 } 562#endif 563 564 template<typename InputIt> 565 DenseMap(const InputIt &I, const InputIt &E) { 566 init(NextPowerOf2(std::distance(I, E))); 567 this->insert(I, E); 568 } 569 570 ~DenseMap() { 571 this->destroyAll(); 572 operator delete(Buckets); 573 } 574 575 void swap(DenseMap& RHS) { 576 std::swap(Buckets, RHS.Buckets); 577 std::swap(NumEntries, RHS.NumEntries); 578 std::swap(NumTombstones, RHS.NumTombstones); 579 std::swap(NumBuckets, RHS.NumBuckets); 580 } 581 582 DenseMap& operator=(const DenseMap& other) { 583 copyFrom(other); 584 return *this; 585 } 586 587#if LLVM_HAS_RVALUE_REFERENCES 588 DenseMap& operator=(DenseMap &&other) { 589 this->destroyAll(); 590 operator delete(Buckets); 591 init(0); 592 swap(other); 593 return *this; 594 } 595#endif 596 597 void copyFrom(const DenseMap& other) { 598 this->destroyAll(); 599 operator delete(Buckets); 600 if (allocateBuckets(other.NumBuckets)) { 601 this->BaseT::copyFrom(other); 602 } else { 603 NumEntries = 0; 604 NumTombstones = 0; 605 } 606 } 607 608 void init(unsigned InitBuckets) { 609 assert(!KeyInfoT::isEqual(this->getEmptyKey(), this->getTombstoneKey()) && 610 "Bad implementation of KeyInfoT: empty key and tombstone key " 611 "should be different"); 612 if (allocateBuckets(InitBuckets)) { 613 this->BaseT::initEmpty(); 614 } else { 615 NumEntries = 0; 616 NumTombstones = 0; 617 } 618 } 619 620 void grow(unsigned AtLeast) { 621 unsigned OldNumBuckets = NumBuckets; 622 BucketT *OldBuckets = Buckets; 623 624 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1)))); 625 assert(Buckets); 626 if (!OldBuckets) { 627 this->BaseT::initEmpty(); 628 return; 629 } 630 631 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets); 632 633 // Free the old table. 634 operator delete(OldBuckets); 635 } 636 637 void shrink_and_clear() { 638 unsigned OldNumEntries = NumEntries; 639 this->destroyAll(); 640 641 // Reduce the number of buckets. 642 unsigned NewNumBuckets = 0; 643 if (OldNumEntries) 644 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1)); 645 if (NewNumBuckets == NumBuckets) { 646 this->BaseT::initEmpty(); 647 return; 648 } 649 650 operator delete(Buckets); 651 init(NewNumBuckets); 652 } 653 654private: 655 unsigned getNumEntries() const { 656 return NumEntries; 657 } 658 void setNumEntries(unsigned Num) { 659 NumEntries = Num; 660 } 661 662 unsigned getNumTombstones() const { 663 return NumTombstones; 664 } 665 void setNumTombstones(unsigned Num) { 666 NumTombstones = Num; 667 } 668 669 BucketT *getBuckets() const { 670 return Buckets; 671 } 672 673 unsigned getNumBuckets() const { 674 return NumBuckets; 675 } 676 677 bool allocateBuckets(unsigned Num) { 678 NumBuckets = Num; 679 if (NumBuckets == 0) { 680 Buckets = 0; 681 return false; 682 } 683 684 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets)); 685 return true; 686 } 687}; 688 689template<typename KeyT, typename ValueT, 690 unsigned InlineBuckets = 4, 691 typename KeyInfoT = DenseMapInfo<KeyT> > 692class SmallDenseMap 693 : public DenseMapBase<SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT>, 694 KeyT, ValueT, KeyInfoT> { 695 // Lift some types from the dependent base class into this class for 696 // simplicity of referring to them. 697 typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT> BaseT; 698 typedef typename BaseT::BucketT BucketT; 699 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT>; 700 701 unsigned Small : 1; 702 unsigned NumEntries : 31; 703 unsigned NumTombstones; 704 705 struct LargeRep { 706 BucketT *Buckets; 707 unsigned NumBuckets; 708 }; 709 710 /// A "union" of an inline bucket array and the struct representing 711 /// a large bucket. This union will be discriminated by the 'Small' bit. 712 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage; 713 714public: 715 explicit SmallDenseMap(unsigned NumInitBuckets = 0) { 716 init(NumInitBuckets); 717 } 718 719 SmallDenseMap(const SmallDenseMap &other) { 720 init(0); 721 copyFrom(other); 722 } 723 724#if LLVM_HAS_RVALUE_REFERENCES 725 SmallDenseMap(SmallDenseMap &&other) { 726 init(0); 727 swap(other); 728 } 729#endif 730 731 template<typename InputIt> 732 SmallDenseMap(const InputIt &I, const InputIt &E) { 733 init(NextPowerOf2(std::distance(I, E))); 734 this->insert(I, E); 735 } 736 737 ~SmallDenseMap() { 738 this->destroyAll(); 739 deallocateBuckets(); 740 } 741 742 void swap(SmallDenseMap& RHS) { 743 unsigned TmpNumEntries = RHS.NumEntries; 744 RHS.NumEntries = NumEntries; 745 NumEntries = TmpNumEntries; 746 std::swap(NumTombstones, RHS.NumTombstones); 747 748 const KeyT EmptyKey = this->getEmptyKey(); 749 const KeyT TombstoneKey = this->getTombstoneKey(); 750 if (Small && RHS.Small) { 751 // If we're swapping inline bucket arrays, we have to cope with some of 752 // the tricky bits of DenseMap's storage system: the buckets are not 753 // fully initialized. Thus we swap every key, but we may have 754 // a one-directional move of the value. 755 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 756 BucketT *LHSB = &getInlineBuckets()[i], 757 *RHSB = &RHS.getInlineBuckets()[i]; 758 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->first, EmptyKey) && 759 !KeyInfoT::isEqual(LHSB->first, TombstoneKey)); 760 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->first, EmptyKey) && 761 !KeyInfoT::isEqual(RHSB->first, TombstoneKey)); 762 if (hasLHSValue && hasRHSValue) { 763 // Swap together if we can... 764 std::swap(*LHSB, *RHSB); 765 continue; 766 } 767 // Swap separately and handle any assymetry. 768 std::swap(LHSB->first, RHSB->first); 769 if (hasLHSValue) { 770 new (&RHSB->second) ValueT(llvm_move(LHSB->second)); 771 LHSB->second.~ValueT(); 772 } else if (hasRHSValue) { 773 new (&LHSB->second) ValueT(llvm_move(RHSB->second)); 774 RHSB->second.~ValueT(); 775 } 776 } 777 return; 778 } 779 if (!Small && !RHS.Small) { 780 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets); 781 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets); 782 return; 783 } 784 785 SmallDenseMap &SmallSide = Small ? *this : RHS; 786 SmallDenseMap &LargeSide = Small ? RHS : *this; 787 788 // First stash the large side's rep and move the small side across. 789 LargeRep TmpRep = llvm_move(*LargeSide.getLargeRep()); 790 LargeSide.getLargeRep()->~LargeRep(); 791 LargeSide.Small = true; 792 // This is similar to the standard move-from-old-buckets, but the bucket 793 // count hasn't actually rotated in this case. So we have to carefully 794 // move construct the keys and values into their new locations, but there 795 // is no need to re-hash things. 796 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 797 BucketT *NewB = &LargeSide.getInlineBuckets()[i], 798 *OldB = &SmallSide.getInlineBuckets()[i]; 799 new (&NewB->first) KeyT(llvm_move(OldB->first)); 800 OldB->first.~KeyT(); 801 if (!KeyInfoT::isEqual(NewB->first, EmptyKey) && 802 !KeyInfoT::isEqual(NewB->first, TombstoneKey)) { 803 new (&NewB->second) ValueT(llvm_move(OldB->second)); 804 OldB->second.~ValueT(); 805 } 806 } 807 808 // The hard part of moving the small buckets across is done, just move 809 // the TmpRep into its new home. 810 SmallSide.Small = false; 811 new (SmallSide.getLargeRep()) LargeRep(llvm_move(TmpRep)); 812 } 813 814 SmallDenseMap& operator=(const SmallDenseMap& other) { 815 copyFrom(other); 816 return *this; 817 } 818 819#if LLVM_HAS_RVALUE_REFERENCES 820 SmallDenseMap& operator=(SmallDenseMap &&other) { 821 this->destroyAll(); 822 deallocateBuckets(); 823 init(0); 824 swap(other); 825 return *this; 826 } 827#endif 828 829 void copyFrom(const SmallDenseMap& other) { 830 this->destroyAll(); 831 deallocateBuckets(); 832 Small = true; 833 if (other.getNumBuckets() > InlineBuckets) { 834 Small = false; 835 allocateBuckets(other.getNumBuckets()); 836 } 837 this->BaseT::copyFrom(other); 838 } 839 840 void init(unsigned InitBuckets) { 841 Small = true; 842 if (InitBuckets > InlineBuckets) { 843 Small = false; 844 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets)); 845 } 846 this->BaseT::initEmpty(); 847 } 848 849 void grow(unsigned AtLeast) { 850 if (AtLeast >= InlineBuckets) 851 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1)); 852 853 if (Small) { 854 if (AtLeast < InlineBuckets) 855 return; // Nothing to do. 856 857 // First move the inline buckets into a temporary storage. 858 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage; 859 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer); 860 BucketT *TmpEnd = TmpBegin; 861 862 // Loop over the buckets, moving non-empty, non-tombstones into the 863 // temporary storage. Have the loop move the TmpEnd forward as it goes. 864 const KeyT EmptyKey = this->getEmptyKey(); 865 const KeyT TombstoneKey = this->getTombstoneKey(); 866 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) { 867 if (!KeyInfoT::isEqual(P->first, EmptyKey) && 868 !KeyInfoT::isEqual(P->first, TombstoneKey)) { 869 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets && 870 "Too many inline buckets!"); 871 new (&TmpEnd->first) KeyT(llvm_move(P->first)); 872 new (&TmpEnd->second) ValueT(llvm_move(P->second)); 873 ++TmpEnd; 874 P->second.~ValueT(); 875 } 876 P->first.~KeyT(); 877 } 878 879 // Now make this map use the large rep, and move all the entries back 880 // into it. 881 Small = false; 882 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 883 this->moveFromOldBuckets(TmpBegin, TmpEnd); 884 return; 885 } 886 887 LargeRep OldRep = llvm_move(*getLargeRep()); 888 getLargeRep()->~LargeRep(); 889 if (AtLeast <= InlineBuckets) { 890 Small = true; 891 } else { 892 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 893 } 894 895 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets); 896 897 // Free the old table. 898 operator delete(OldRep.Buckets); 899 } 900 901 void shrink_and_clear() { 902 unsigned OldSize = this->size(); 903 this->destroyAll(); 904 905 // Reduce the number of buckets. 906 unsigned NewNumBuckets = 0; 907 if (OldSize) { 908 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1); 909 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u) 910 NewNumBuckets = 64; 911 } 912 if ((Small && NewNumBuckets <= InlineBuckets) || 913 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) { 914 this->BaseT::initEmpty(); 915 return; 916 } 917 918 deallocateBuckets(); 919 init(NewNumBuckets); 920 } 921 922private: 923 unsigned getNumEntries() const { 924 return NumEntries; 925 } 926 void setNumEntries(unsigned Num) { 927 assert(Num < INT_MAX && "Cannot support more than INT_MAX entries"); 928 NumEntries = Num; 929 } 930 931 unsigned getNumTombstones() const { 932 return NumTombstones; 933 } 934 void setNumTombstones(unsigned Num) { 935 NumTombstones = Num; 936 } 937 938 const BucketT *getInlineBuckets() const { 939 assert(Small); 940 // Note that this cast does not violate aliasing rules as we assert that 941 // the memory's dynamic type is the small, inline bucket buffer, and the 942 // 'storage.buffer' static type is 'char *'. 943 return reinterpret_cast<const BucketT *>(storage.buffer); 944 } 945 BucketT *getInlineBuckets() { 946 return const_cast<BucketT *>( 947 const_cast<const SmallDenseMap *>(this)->getInlineBuckets()); 948 } 949 const LargeRep *getLargeRep() const { 950 assert(!Small); 951 // Note, same rule about aliasing as with getInlineBuckets. 952 return reinterpret_cast<const LargeRep *>(storage.buffer); 953 } 954 LargeRep *getLargeRep() { 955 return const_cast<LargeRep *>( 956 const_cast<const SmallDenseMap *>(this)->getLargeRep()); 957 } 958 959 const BucketT *getBuckets() const { 960 return Small ? getInlineBuckets() : getLargeRep()->Buckets; 961 } 962 BucketT *getBuckets() { 963 return const_cast<BucketT *>( 964 const_cast<const SmallDenseMap *>(this)->getBuckets()); 965 } 966 unsigned getNumBuckets() const { 967 return Small ? InlineBuckets : getLargeRep()->NumBuckets; 968 } 969 970 void deallocateBuckets() { 971 if (Small) 972 return; 973 974 operator delete(getLargeRep()->Buckets); 975 getLargeRep()->~LargeRep(); 976 } 977 978 LargeRep allocateBuckets(unsigned Num) { 979 assert(Num > InlineBuckets && "Must allocate more buckets than are inline"); 980 LargeRep Rep = { 981 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num 982 }; 983 return Rep; 984 } 985}; 986 987template<typename KeyT, typename ValueT, 988 typename KeyInfoT, bool IsConst> 989class DenseMapIterator { 990 typedef std::pair<KeyT, ValueT> Bucket; 991 typedef DenseMapIterator<KeyT, ValueT, 992 KeyInfoT, true> ConstIterator; 993 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, true>; 994public: 995 typedef ptrdiff_t difference_type; 996 typedef typename conditional<IsConst, const Bucket, Bucket>::type value_type; 997 typedef value_type *pointer; 998 typedef value_type &reference; 999 typedef std::forward_iterator_tag iterator_category; 1000private: 1001 pointer Ptr, End; 1002public: 1003 DenseMapIterator() : Ptr(0), End(0) {} 1004 1005 DenseMapIterator(pointer Pos, pointer E, bool NoAdvance = false) 1006 : Ptr(Pos), End(E) { 1007 if (!NoAdvance) AdvancePastEmptyBuckets(); 1008 } 1009 1010 // If IsConst is true this is a converting constructor from iterator to 1011 // const_iterator and the default copy constructor is used. 1012 // Otherwise this is a copy constructor for iterator. 1013 DenseMapIterator(const DenseMapIterator<KeyT, ValueT, 1014 KeyInfoT, false>& I) 1015 : Ptr(I.Ptr), End(I.End) {} 1016 1017 reference operator*() const { 1018 return *Ptr; 1019 } 1020 pointer operator->() const { 1021 return Ptr; 1022 } 1023 1024 bool operator==(const ConstIterator &RHS) const { 1025 return Ptr == RHS.operator->(); 1026 } 1027 bool operator!=(const ConstIterator &RHS) const { 1028 return Ptr != RHS.operator->(); 1029 } 1030 1031 inline DenseMapIterator& operator++() { // Preincrement 1032 ++Ptr; 1033 AdvancePastEmptyBuckets(); 1034 return *this; 1035 } 1036 DenseMapIterator operator++(int) { // Postincrement 1037 DenseMapIterator tmp = *this; ++*this; return tmp; 1038 } 1039 1040private: 1041 void AdvancePastEmptyBuckets() { 1042 const KeyT Empty = KeyInfoT::getEmptyKey(); 1043 const KeyT Tombstone = KeyInfoT::getTombstoneKey(); 1044 1045 while (Ptr != End && 1046 (KeyInfoT::isEqual(Ptr->first, Empty) || 1047 KeyInfoT::isEqual(Ptr->first, Tombstone))) 1048 ++Ptr; 1049 } 1050}; 1051 1052template<typename KeyT, typename ValueT, typename KeyInfoT> 1053static inline size_t 1054capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) { 1055 return X.getMemorySize(); 1056} 1057 1058} // end namespace llvm 1059 1060#endif 1061