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 32 namespace llvm { 33 34 template<typename KeyT, typename ValueT, 35 typename KeyInfoT = DenseMapInfo<KeyT>, 36 bool IsConst = false> 37 class DenseMapIterator; 38 39 template<typename DerivedT, 40 typename KeyT, typename ValueT, typename KeyInfoT> 41 class DenseMapBase { 42 protected: 43 typedef std::pair<KeyT, ValueT> BucketT; 44 45 public: 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(); } 244 245 protected: 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 } 344 345 private: 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 } 520 521 public: 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 }; 530 531 template<typename KeyT, typename ValueT, 532 typename KeyInfoT = DenseMapInfo<KeyT> > 533 class 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; 546 547 public: 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 if (allocateBuckets(InitBuckets)) { 610 this->BaseT::initEmpty(); 611 } else { 612 NumEntries = 0; 613 NumTombstones = 0; 614 } 615 } 616 617 void grow(unsigned AtLeast) { 618 unsigned OldNumBuckets = NumBuckets; 619 BucketT *OldBuckets = Buckets; 620 621 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1)))); 622 assert(Buckets); 623 if (!OldBuckets) { 624 this->BaseT::initEmpty(); 625 return; 626 } 627 628 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets); 629 630 // Free the old table. 631 operator delete(OldBuckets); 632 } 633 634 void shrink_and_clear() { 635 unsigned OldNumEntries = NumEntries; 636 this->destroyAll(); 637 638 // Reduce the number of buckets. 639 unsigned NewNumBuckets = 0; 640 if (OldNumEntries) 641 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1)); 642 if (NewNumBuckets == NumBuckets) { 643 this->BaseT::initEmpty(); 644 return; 645 } 646 647 operator delete(Buckets); 648 init(NewNumBuckets); 649 } 650 651 private: 652 unsigned getNumEntries() const { 653 return NumEntries; 654 } 655 void setNumEntries(unsigned Num) { 656 NumEntries = Num; 657 } 658 659 unsigned getNumTombstones() const { 660 return NumTombstones; 661 } 662 void setNumTombstones(unsigned Num) { 663 NumTombstones = Num; 664 } 665 666 BucketT *getBuckets() const { 667 return Buckets; 668 } 669 670 unsigned getNumBuckets() const { 671 return NumBuckets; 672 } 673 674 bool allocateBuckets(unsigned Num) { 675 NumBuckets = Num; 676 if (NumBuckets == 0) { 677 Buckets = 0; 678 return false; 679 } 680 681 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets)); 682 return true; 683 } 684 }; 685 686 template<typename KeyT, typename ValueT, 687 unsigned InlineBuckets = 4, 688 typename KeyInfoT = DenseMapInfo<KeyT> > 689 class SmallDenseMap 690 : public DenseMapBase<SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT>, 691 KeyT, ValueT, KeyInfoT> { 692 // Lift some types from the dependent base class into this class for 693 // simplicity of referring to them. 694 typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT> BaseT; 695 typedef typename BaseT::BucketT BucketT; 696 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT>; 697 698 unsigned Small : 1; 699 unsigned NumEntries : 31; 700 unsigned NumTombstones; 701 702 struct LargeRep { 703 BucketT *Buckets; 704 unsigned NumBuckets; 705 }; 706 707 /// A "union" of an inline bucket array and the struct representing 708 /// a large bucket. This union will be discriminated by the 'Small' bit. 709 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage; 710 711 public: 712 explicit SmallDenseMap(unsigned NumInitBuckets = 0) { 713 init(NumInitBuckets); 714 } 715 716 SmallDenseMap(const SmallDenseMap &other) { 717 init(0); 718 copyFrom(other); 719 } 720 721 #if LLVM_HAS_RVALUE_REFERENCES 722 SmallDenseMap(SmallDenseMap &&other) { 723 init(0); 724 swap(other); 725 } 726 #endif 727 728 template<typename InputIt> 729 SmallDenseMap(const InputIt &I, const InputIt &E) { 730 init(NextPowerOf2(std::distance(I, E))); 731 this->insert(I, E); 732 } 733 734 ~SmallDenseMap() { 735 this->destroyAll(); 736 deallocateBuckets(); 737 } 738 739 void swap(SmallDenseMap& RHS) { 740 unsigned TmpNumEntries = RHS.NumEntries; 741 RHS.NumEntries = NumEntries; 742 NumEntries = TmpNumEntries; 743 std::swap(NumTombstones, RHS.NumTombstones); 744 745 const KeyT EmptyKey = this->getEmptyKey(); 746 const KeyT TombstoneKey = this->getTombstoneKey(); 747 if (Small && RHS.Small) { 748 // If we're swapping inline bucket arrays, we have to cope with some of 749 // the tricky bits of DenseMap's storage system: the buckets are not 750 // fully initialized. Thus we swap every key, but we may have 751 // a one-directional move of the value. 752 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 753 BucketT *LHSB = &getInlineBuckets()[i], 754 *RHSB = &RHS.getInlineBuckets()[i]; 755 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->first, EmptyKey) && 756 !KeyInfoT::isEqual(LHSB->first, TombstoneKey)); 757 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->first, EmptyKey) && 758 !KeyInfoT::isEqual(RHSB->first, TombstoneKey)); 759 if (hasLHSValue && hasRHSValue) { 760 // Swap together if we can... 761 std::swap(*LHSB, *RHSB); 762 continue; 763 } 764 // Swap separately and handle any assymetry. 765 std::swap(LHSB->first, RHSB->first); 766 if (hasLHSValue) { 767 new (&RHSB->second) ValueT(llvm_move(LHSB->second)); 768 LHSB->second.~ValueT(); 769 } else if (hasRHSValue) { 770 new (&LHSB->second) ValueT(llvm_move(RHSB->second)); 771 RHSB->second.~ValueT(); 772 } 773 } 774 return; 775 } 776 if (!Small && !RHS.Small) { 777 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets); 778 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets); 779 return; 780 } 781 782 SmallDenseMap &SmallSide = Small ? *this : RHS; 783 SmallDenseMap &LargeSide = Small ? RHS : *this; 784 785 // First stash the large side's rep and move the small side across. 786 LargeRep TmpRep = llvm_move(*LargeSide.getLargeRep()); 787 LargeSide.getLargeRep()->~LargeRep(); 788 LargeSide.Small = true; 789 // This is similar to the standard move-from-old-buckets, but the bucket 790 // count hasn't actually rotated in this case. So we have to carefully 791 // move construct the keys and values into their new locations, but there 792 // is no need to re-hash things. 793 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 794 BucketT *NewB = &LargeSide.getInlineBuckets()[i], 795 *OldB = &SmallSide.getInlineBuckets()[i]; 796 new (&NewB->first) KeyT(llvm_move(OldB->first)); 797 OldB->first.~KeyT(); 798 if (!KeyInfoT::isEqual(NewB->first, EmptyKey) && 799 !KeyInfoT::isEqual(NewB->first, TombstoneKey)) { 800 new (&NewB->second) ValueT(llvm_move(OldB->second)); 801 OldB->second.~ValueT(); 802 } 803 } 804 805 // The hard part of moving the small buckets across is done, just move 806 // the TmpRep into its new home. 807 SmallSide.Small = false; 808 new (SmallSide.getLargeRep()) LargeRep(llvm_move(TmpRep)); 809 } 810 811 SmallDenseMap& operator=(const SmallDenseMap& other) { 812 copyFrom(other); 813 return *this; 814 } 815 816 #if LLVM_HAS_RVALUE_REFERENCES 817 SmallDenseMap& operator=(SmallDenseMap &&other) { 818 this->destroyAll(); 819 deallocateBuckets(); 820 init(0); 821 swap(other); 822 return *this; 823 } 824 #endif 825 826 void copyFrom(const SmallDenseMap& other) { 827 this->destroyAll(); 828 deallocateBuckets(); 829 Small = true; 830 if (other.getNumBuckets() > InlineBuckets) { 831 Small = false; 832 allocateBuckets(other.getNumBuckets()); 833 } 834 this->BaseT::copyFrom(other); 835 } 836 837 void init(unsigned InitBuckets) { 838 Small = true; 839 if (InitBuckets > InlineBuckets) { 840 Small = false; 841 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets)); 842 } 843 this->BaseT::initEmpty(); 844 } 845 846 void grow(unsigned AtLeast) { 847 if (AtLeast >= InlineBuckets) 848 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1)); 849 850 if (Small) { 851 if (AtLeast < InlineBuckets) 852 return; // Nothing to do. 853 854 // First move the inline buckets into a temporary storage. 855 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage; 856 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer); 857 BucketT *TmpEnd = TmpBegin; 858 859 // Loop over the buckets, moving non-empty, non-tombstones into the 860 // temporary storage. Have the loop move the TmpEnd forward as it goes. 861 const KeyT EmptyKey = this->getEmptyKey(); 862 const KeyT TombstoneKey = this->getTombstoneKey(); 863 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) { 864 if (!KeyInfoT::isEqual(P->first, EmptyKey) && 865 !KeyInfoT::isEqual(P->first, TombstoneKey)) { 866 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets && 867 "Too many inline buckets!"); 868 new (&TmpEnd->first) KeyT(llvm_move(P->first)); 869 new (&TmpEnd->second) ValueT(llvm_move(P->second)); 870 ++TmpEnd; 871 P->second.~ValueT(); 872 } 873 P->first.~KeyT(); 874 } 875 876 // Now make this map use the large rep, and move all the entries back 877 // into it. 878 Small = false; 879 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 880 this->moveFromOldBuckets(TmpBegin, TmpEnd); 881 return; 882 } 883 884 LargeRep OldRep = llvm_move(*getLargeRep()); 885 getLargeRep()->~LargeRep(); 886 if (AtLeast <= InlineBuckets) { 887 Small = true; 888 } else { 889 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 890 } 891 892 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets); 893 894 // Free the old table. 895 operator delete(OldRep.Buckets); 896 } 897 898 void shrink_and_clear() { 899 unsigned OldSize = this->size(); 900 this->destroyAll(); 901 902 // Reduce the number of buckets. 903 unsigned NewNumBuckets = 0; 904 if (OldSize) { 905 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1); 906 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u) 907 NewNumBuckets = 64; 908 } 909 if ((Small && NewNumBuckets <= InlineBuckets) || 910 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) { 911 this->BaseT::initEmpty(); 912 return; 913 } 914 915 deallocateBuckets(); 916 init(NewNumBuckets); 917 } 918 919 private: 920 unsigned getNumEntries() const { 921 return NumEntries; 922 } 923 void setNumEntries(unsigned Num) { 924 assert(Num < INT_MAX && "Cannot support more than INT_MAX entries"); 925 NumEntries = Num; 926 } 927 928 unsigned getNumTombstones() const { 929 return NumTombstones; 930 } 931 void setNumTombstones(unsigned Num) { 932 NumTombstones = Num; 933 } 934 935 const BucketT *getInlineBuckets() const { 936 assert(Small); 937 // Note that this cast does not violate aliasing rules as we assert that 938 // the memory's dynamic type is the small, inline bucket buffer, and the 939 // 'storage.buffer' static type is 'char *'. 940 return reinterpret_cast<const BucketT *>(storage.buffer); 941 } 942 BucketT *getInlineBuckets() { 943 return const_cast<BucketT *>( 944 const_cast<const SmallDenseMap *>(this)->getInlineBuckets()); 945 } 946 const LargeRep *getLargeRep() const { 947 assert(!Small); 948 // Note, same rule about aliasing as with getInlineBuckets. 949 return reinterpret_cast<const LargeRep *>(storage.buffer); 950 } 951 LargeRep *getLargeRep() { 952 return const_cast<LargeRep *>( 953 const_cast<const SmallDenseMap *>(this)->getLargeRep()); 954 } 955 956 const BucketT *getBuckets() const { 957 return Small ? getInlineBuckets() : getLargeRep()->Buckets; 958 } 959 BucketT *getBuckets() { 960 return const_cast<BucketT *>( 961 const_cast<const SmallDenseMap *>(this)->getBuckets()); 962 } 963 unsigned getNumBuckets() const { 964 return Small ? InlineBuckets : getLargeRep()->NumBuckets; 965 } 966 967 void deallocateBuckets() { 968 if (Small) 969 return; 970 971 operator delete(getLargeRep()->Buckets); 972 getLargeRep()->~LargeRep(); 973 } 974 975 LargeRep allocateBuckets(unsigned Num) { 976 assert(Num > InlineBuckets && "Must allocate more buckets than are inline"); 977 LargeRep Rep = { 978 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num 979 }; 980 return Rep; 981 } 982 }; 983 984 template<typename KeyT, typename ValueT, 985 typename KeyInfoT, bool IsConst> 986 class DenseMapIterator { 987 typedef std::pair<KeyT, ValueT> Bucket; 988 typedef DenseMapIterator<KeyT, ValueT, 989 KeyInfoT, true> ConstIterator; 990 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, true>; 991 public: 992 typedef ptrdiff_t difference_type; 993 typedef typename conditional<IsConst, const Bucket, Bucket>::type value_type; 994 typedef value_type *pointer; 995 typedef value_type &reference; 996 typedef std::forward_iterator_tag iterator_category; 997 private: 998 pointer Ptr, End; 999 public: 1000 DenseMapIterator() : Ptr(0), End(0) {} 1001 1002 DenseMapIterator(pointer Pos, pointer E, bool NoAdvance = false) 1003 : Ptr(Pos), End(E) { 1004 if (!NoAdvance) AdvancePastEmptyBuckets(); 1005 } 1006 1007 // If IsConst is true this is a converting constructor from iterator to 1008 // const_iterator and the default copy constructor is used. 1009 // Otherwise this is a copy constructor for iterator. 1010 DenseMapIterator(const DenseMapIterator<KeyT, ValueT, 1011 KeyInfoT, false>& I) 1012 : Ptr(I.Ptr), End(I.End) {} 1013 1014 reference operator*() const { 1015 return *Ptr; 1016 } 1017 pointer operator->() const { 1018 return Ptr; 1019 } 1020 1021 bool operator==(const ConstIterator &RHS) const { 1022 return Ptr == RHS.operator->(); 1023 } 1024 bool operator!=(const ConstIterator &RHS) const { 1025 return Ptr != RHS.operator->(); 1026 } 1027 1028 inline DenseMapIterator& operator++() { // Preincrement 1029 ++Ptr; 1030 AdvancePastEmptyBuckets(); 1031 return *this; 1032 } 1033 DenseMapIterator operator++(int) { // Postincrement 1034 DenseMapIterator tmp = *this; ++*this; return tmp; 1035 } 1036 1037 private: 1038 void AdvancePastEmptyBuckets() { 1039 const KeyT Empty = KeyInfoT::getEmptyKey(); 1040 const KeyT Tombstone = KeyInfoT::getTombstoneKey(); 1041 1042 while (Ptr != End && 1043 (KeyInfoT::isEqual(Ptr->first, Empty) || 1044 KeyInfoT::isEqual(Ptr->first, Tombstone))) 1045 ++Ptr; 1046 } 1047 }; 1048 1049 template<typename KeyT, typename ValueT, typename KeyInfoT> 1050 static inline size_t 1051 capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) { 1052 return X.getMemorySize(); 1053 } 1054 1055 } // end namespace llvm 1056 1057 #endif 1058