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/ADT/EpochTracker.h" 19#include "llvm/Support/AlignOf.h" 20#include "llvm/Support/Compiler.h" 21#include "llvm/Support/MathExtras.h" 22#include "llvm/Support/ReverseIteration.h" 23#include "llvm/Support/type_traits.h" 24#include <algorithm> 25#include <cassert> 26#include <cstddef> 27#include <cstring> 28#include <iterator> 29#include <new> 30#include <type_traits> 31#include <utility> 32 33namespace llvm { 34 35namespace detail { 36 37// We extend a pair to allow users to override the bucket type with their own 38// implementation without requiring two members. 39template <typename KeyT, typename ValueT> 40struct DenseMapPair : public std::pair<KeyT, ValueT> { 41 KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; } 42 const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; } 43 ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; } 44 const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; } 45}; 46 47} // end namespace detail 48 49template < 50 typename KeyT, typename ValueT, typename KeyInfoT = DenseMapInfo<KeyT>, 51 typename Bucket = detail::DenseMapPair<KeyT, ValueT>, bool IsConst = false> 52class DenseMapIterator; 53 54template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT, 55 typename BucketT> 56class DenseMapBase : public DebugEpochBase { 57 template <typename T> 58 using const_arg_type_t = typename const_pointer_or_const_ref<T>::type; 59 60public: 61 using size_type = unsigned; 62 using key_type = KeyT; 63 using mapped_type = ValueT; 64 using value_type = BucketT; 65 66 using iterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT>; 67 using const_iterator = 68 DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>; 69 70 inline iterator begin() { 71 // When the map is empty, avoid the overhead of advancing/retreating past 72 // empty buckets. 73 if (empty()) 74 return end(); 75 if (shouldReverseIterate<KeyT>()) 76 return makeIterator(getBucketsEnd() - 1, getBuckets(), *this); 77 return makeIterator(getBuckets(), getBucketsEnd(), *this); 78 } 79 inline iterator end() { 80 return makeIterator(getBucketsEnd(), getBucketsEnd(), *this, true); 81 } 82 inline const_iterator begin() const { 83 if (empty()) 84 return end(); 85 if (shouldReverseIterate<KeyT>()) 86 return makeConstIterator(getBucketsEnd() - 1, getBuckets(), *this); 87 return makeConstIterator(getBuckets(), getBucketsEnd(), *this); 88 } 89 inline const_iterator end() const { 90 return makeConstIterator(getBucketsEnd(), getBucketsEnd(), *this, true); 91 } 92 93 LLVM_NODISCARD bool empty() const { 94 return getNumEntries() == 0; 95 } 96 unsigned size() const { return getNumEntries(); } 97 98 /// Grow the densemap so that it can contain at least \p NumEntries items 99 /// before resizing again. 100 void reserve(size_type NumEntries) { 101 auto NumBuckets = getMinBucketToReserveForEntries(NumEntries); 102 incrementEpoch(); 103 if (NumBuckets > getNumBuckets()) 104 grow(NumBuckets); 105 } 106 107 void clear() { 108 incrementEpoch(); 109 if (getNumEntries() == 0 && getNumTombstones() == 0) return; 110 111 // If the capacity of the array is huge, and the # elements used is small, 112 // shrink the array. 113 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) { 114 shrink_and_clear(); 115 return; 116 } 117 118 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); 119 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value) { 120 // Use a simpler loop when these are trivial types. 121 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) 122 P->getFirst() = EmptyKey; 123 } else { 124 unsigned NumEntries = getNumEntries(); 125 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { 126 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) { 127 if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) { 128 P->getSecond().~ValueT(); 129 --NumEntries; 130 } 131 P->getFirst() = EmptyKey; 132 } 133 } 134 assert(NumEntries == 0 && "Node count imbalance!"); 135 } 136 setNumEntries(0); 137 setNumTombstones(0); 138 } 139 140 /// Return 1 if the specified key is in the map, 0 otherwise. 141 size_type count(const_arg_type_t<KeyT> Val) const { 142 const BucketT *TheBucket; 143 return LookupBucketFor(Val, TheBucket) ? 1 : 0; 144 } 145 146 iterator find(const_arg_type_t<KeyT> Val) { 147 BucketT *TheBucket; 148 if (LookupBucketFor(Val, TheBucket)) 149 return makeIterator(TheBucket, getBucketsEnd(), *this, true); 150 return end(); 151 } 152 const_iterator find(const_arg_type_t<KeyT> Val) const { 153 const BucketT *TheBucket; 154 if (LookupBucketFor(Val, TheBucket)) 155 return makeConstIterator(TheBucket, getBucketsEnd(), *this, true); 156 return end(); 157 } 158 159 /// Alternate version of find() which allows a different, and possibly 160 /// less expensive, key type. 161 /// The DenseMapInfo is responsible for supplying methods 162 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key 163 /// type used. 164 template<class LookupKeyT> 165 iterator find_as(const LookupKeyT &Val) { 166 BucketT *TheBucket; 167 if (LookupBucketFor(Val, TheBucket)) 168 return makeIterator(TheBucket, getBucketsEnd(), *this, true); 169 return end(); 170 } 171 template<class LookupKeyT> 172 const_iterator find_as(const LookupKeyT &Val) const { 173 const BucketT *TheBucket; 174 if (LookupBucketFor(Val, TheBucket)) 175 return makeConstIterator(TheBucket, getBucketsEnd(), *this, true); 176 return end(); 177 } 178 179 /// lookup - Return the entry for the specified key, or a default 180 /// constructed value if no such entry exists. 181 ValueT lookup(const_arg_type_t<KeyT> Val) const { 182 const BucketT *TheBucket; 183 if (LookupBucketFor(Val, TheBucket)) 184 return TheBucket->getSecond(); 185 return ValueT(); 186 } 187 188 // Inserts key,value pair into the map if the key isn't already in the map. 189 // If the key is already in the map, it returns false and doesn't update the 190 // value. 191 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) { 192 return try_emplace(KV.first, KV.second); 193 } 194 195 // Inserts key,value pair into the map if the key isn't already in the map. 196 // If the key is already in the map, it returns false and doesn't update the 197 // value. 198 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) { 199 return try_emplace(std::move(KV.first), std::move(KV.second)); 200 } 201 202 // Inserts key,value pair into the map if the key isn't already in the map. 203 // The value is constructed in-place if the key is not in the map, otherwise 204 // it is not moved. 205 template <typename... Ts> 206 std::pair<iterator, bool> try_emplace(KeyT &&Key, Ts &&... Args) { 207 BucketT *TheBucket; 208 if (LookupBucketFor(Key, TheBucket)) 209 return std::make_pair( 210 makeIterator(TheBucket, getBucketsEnd(), *this, true), 211 false); // Already in map. 212 213 // Otherwise, insert the new element. 214 TheBucket = 215 InsertIntoBucket(TheBucket, std::move(Key), std::forward<Ts>(Args)...); 216 return std::make_pair( 217 makeIterator(TheBucket, getBucketsEnd(), *this, true), 218 true); 219 } 220 221 // Inserts key,value pair into the map if the key isn't already in the map. 222 // The value is constructed in-place if the key is not in the map, otherwise 223 // it is not moved. 224 template <typename... Ts> 225 std::pair<iterator, bool> try_emplace(const KeyT &Key, Ts &&... Args) { 226 BucketT *TheBucket; 227 if (LookupBucketFor(Key, TheBucket)) 228 return std::make_pair( 229 makeIterator(TheBucket, getBucketsEnd(), *this, true), 230 false); // Already in map. 231 232 // Otherwise, insert the new element. 233 TheBucket = InsertIntoBucket(TheBucket, Key, std::forward<Ts>(Args)...); 234 return std::make_pair( 235 makeIterator(TheBucket, getBucketsEnd(), *this, true), 236 true); 237 } 238 239 /// Alternate version of insert() which allows a different, and possibly 240 /// less expensive, key type. 241 /// The DenseMapInfo is responsible for supplying methods 242 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key 243 /// type used. 244 template <typename LookupKeyT> 245 std::pair<iterator, bool> insert_as(std::pair<KeyT, ValueT> &&KV, 246 const LookupKeyT &Val) { 247 BucketT *TheBucket; 248 if (LookupBucketFor(Val, TheBucket)) 249 return std::make_pair( 250 makeIterator(TheBucket, getBucketsEnd(), *this, true), 251 false); // Already in map. 252 253 // Otherwise, insert the new element. 254 TheBucket = InsertIntoBucketWithLookup(TheBucket, std::move(KV.first), 255 std::move(KV.second), Val); 256 return std::make_pair( 257 makeIterator(TheBucket, getBucketsEnd(), *this, true), 258 true); 259 } 260 261 /// insert - Range insertion of pairs. 262 template<typename InputIt> 263 void insert(InputIt I, InputIt E) { 264 for (; I != E; ++I) 265 insert(*I); 266 } 267 268 bool erase(const KeyT &Val) { 269 BucketT *TheBucket; 270 if (!LookupBucketFor(Val, TheBucket)) 271 return false; // not in map. 272 273 TheBucket->getSecond().~ValueT(); 274 TheBucket->getFirst() = getTombstoneKey(); 275 decrementNumEntries(); 276 incrementNumTombstones(); 277 return true; 278 } 279 void erase(iterator I) { 280 BucketT *TheBucket = &*I; 281 TheBucket->getSecond().~ValueT(); 282 TheBucket->getFirst() = getTombstoneKey(); 283 decrementNumEntries(); 284 incrementNumTombstones(); 285 } 286 287 value_type& FindAndConstruct(const KeyT &Key) { 288 BucketT *TheBucket; 289 if (LookupBucketFor(Key, TheBucket)) 290 return *TheBucket; 291 292 return *InsertIntoBucket(TheBucket, Key); 293 } 294 295 ValueT &operator[](const KeyT &Key) { 296 return FindAndConstruct(Key).second; 297 } 298 299 value_type& FindAndConstruct(KeyT &&Key) { 300 BucketT *TheBucket; 301 if (LookupBucketFor(Key, TheBucket)) 302 return *TheBucket; 303 304 return *InsertIntoBucket(TheBucket, std::move(Key)); 305 } 306 307 ValueT &operator[](KeyT &&Key) { 308 return FindAndConstruct(std::move(Key)).second; 309 } 310 311 /// isPointerIntoBucketsArray - Return true if the specified pointer points 312 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or 313 /// value in the DenseMap). 314 bool isPointerIntoBucketsArray(const void *Ptr) const { 315 return Ptr >= getBuckets() && Ptr < getBucketsEnd(); 316 } 317 318 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets 319 /// array. In conjunction with the previous method, this can be used to 320 /// determine whether an insertion caused the DenseMap to reallocate. 321 const void *getPointerIntoBucketsArray() const { return getBuckets(); } 322 323protected: 324 DenseMapBase() = default; 325 326 void destroyAll() { 327 if (getNumBuckets() == 0) // Nothing to do. 328 return; 329 330 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey(); 331 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) { 332 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) && 333 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) 334 P->getSecond().~ValueT(); 335 P->getFirst().~KeyT(); 336 } 337 } 338 339 void initEmpty() { 340 setNumEntries(0); 341 setNumTombstones(0); 342 343 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 && 344 "# initial buckets must be a power of two!"); 345 const KeyT EmptyKey = getEmptyKey(); 346 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B) 347 ::new (&B->getFirst()) KeyT(EmptyKey); 348 } 349 350 /// Returns the number of buckets to allocate to ensure that the DenseMap can 351 /// accommodate \p NumEntries without need to grow(). 352 unsigned getMinBucketToReserveForEntries(unsigned NumEntries) { 353 // Ensure that "NumEntries * 4 < NumBuckets * 3" 354 if (NumEntries == 0) 355 return 0; 356 // +1 is required because of the strict equality. 357 // For example if NumEntries is 48, we need to return 401. 358 return NextPowerOf2(NumEntries * 4 / 3 + 1); 359 } 360 361 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) { 362 initEmpty(); 363 364 // Insert all the old elements. 365 const KeyT EmptyKey = getEmptyKey(); 366 const KeyT TombstoneKey = getTombstoneKey(); 367 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) { 368 if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) && 369 !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) { 370 // Insert the key/value into the new table. 371 BucketT *DestBucket; 372 bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket); 373 (void)FoundVal; // silence warning. 374 assert(!FoundVal && "Key already in new map?"); 375 DestBucket->getFirst() = std::move(B->getFirst()); 376 ::new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond())); 377 incrementNumEntries(); 378 379 // Free the value. 380 B->getSecond().~ValueT(); 381 } 382 B->getFirst().~KeyT(); 383 } 384 } 385 386 template <typename OtherBaseT> 387 void copyFrom( 388 const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) { 389 assert(&other != this); 390 assert(getNumBuckets() == other.getNumBuckets()); 391 392 setNumEntries(other.getNumEntries()); 393 setNumTombstones(other.getNumTombstones()); 394 395 if (isPodLike<KeyT>::value && isPodLike<ValueT>::value) 396 memcpy(getBuckets(), other.getBuckets(), 397 getNumBuckets() * sizeof(BucketT)); 398 else 399 for (size_t i = 0; i < getNumBuckets(); ++i) { 400 ::new (&getBuckets()[i].getFirst()) 401 KeyT(other.getBuckets()[i].getFirst()); 402 if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) && 403 !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey())) 404 ::new (&getBuckets()[i].getSecond()) 405 ValueT(other.getBuckets()[i].getSecond()); 406 } 407 } 408 409 static unsigned getHashValue(const KeyT &Val) { 410 return KeyInfoT::getHashValue(Val); 411 } 412 413 template<typename LookupKeyT> 414 static unsigned getHashValue(const LookupKeyT &Val) { 415 return KeyInfoT::getHashValue(Val); 416 } 417 418 static const KeyT getEmptyKey() { 419 static_assert(std::is_base_of<DenseMapBase, DerivedT>::value, 420 "Must pass the derived type to this template!"); 421 return KeyInfoT::getEmptyKey(); 422 } 423 424 static const KeyT getTombstoneKey() { 425 return KeyInfoT::getTombstoneKey(); 426 } 427 428private: 429 iterator makeIterator(BucketT *P, BucketT *E, 430 DebugEpochBase &Epoch, 431 bool NoAdvance=false) { 432 if (shouldReverseIterate<KeyT>()) { 433 BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1; 434 return iterator(B, E, Epoch, NoAdvance); 435 } 436 return iterator(P, E, Epoch, NoAdvance); 437 } 438 439 const_iterator makeConstIterator(const BucketT *P, const BucketT *E, 440 const DebugEpochBase &Epoch, 441 const bool NoAdvance=false) const { 442 if (shouldReverseIterate<KeyT>()) { 443 const BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1; 444 return const_iterator(B, E, Epoch, NoAdvance); 445 } 446 return const_iterator(P, E, Epoch, NoAdvance); 447 } 448 449 unsigned getNumEntries() const { 450 return static_cast<const DerivedT *>(this)->getNumEntries(); 451 } 452 453 void setNumEntries(unsigned Num) { 454 static_cast<DerivedT *>(this)->setNumEntries(Num); 455 } 456 457 void incrementNumEntries() { 458 setNumEntries(getNumEntries() + 1); 459 } 460 461 void decrementNumEntries() { 462 setNumEntries(getNumEntries() - 1); 463 } 464 465 unsigned getNumTombstones() const { 466 return static_cast<const DerivedT *>(this)->getNumTombstones(); 467 } 468 469 void setNumTombstones(unsigned Num) { 470 static_cast<DerivedT *>(this)->setNumTombstones(Num); 471 } 472 473 void incrementNumTombstones() { 474 setNumTombstones(getNumTombstones() + 1); 475 } 476 477 void decrementNumTombstones() { 478 setNumTombstones(getNumTombstones() - 1); 479 } 480 481 const BucketT *getBuckets() const { 482 return static_cast<const DerivedT *>(this)->getBuckets(); 483 } 484 485 BucketT *getBuckets() { 486 return static_cast<DerivedT *>(this)->getBuckets(); 487 } 488 489 unsigned getNumBuckets() const { 490 return static_cast<const DerivedT *>(this)->getNumBuckets(); 491 } 492 493 BucketT *getBucketsEnd() { 494 return getBuckets() + getNumBuckets(); 495 } 496 497 const BucketT *getBucketsEnd() const { 498 return getBuckets() + getNumBuckets(); 499 } 500 501 void grow(unsigned AtLeast) { 502 static_cast<DerivedT *>(this)->grow(AtLeast); 503 } 504 505 void shrink_and_clear() { 506 static_cast<DerivedT *>(this)->shrink_and_clear(); 507 } 508 509 template <typename KeyArg, typename... ValueArgs> 510 BucketT *InsertIntoBucket(BucketT *TheBucket, KeyArg &&Key, 511 ValueArgs &&... Values) { 512 TheBucket = InsertIntoBucketImpl(Key, Key, TheBucket); 513 514 TheBucket->getFirst() = std::forward<KeyArg>(Key); 515 ::new (&TheBucket->getSecond()) ValueT(std::forward<ValueArgs>(Values)...); 516 return TheBucket; 517 } 518 519 template <typename LookupKeyT> 520 BucketT *InsertIntoBucketWithLookup(BucketT *TheBucket, KeyT &&Key, 521 ValueT &&Value, LookupKeyT &Lookup) { 522 TheBucket = InsertIntoBucketImpl(Key, Lookup, TheBucket); 523 524 TheBucket->getFirst() = std::move(Key); 525 ::new (&TheBucket->getSecond()) ValueT(std::move(Value)); 526 return TheBucket; 527 } 528 529 template <typename LookupKeyT> 530 BucketT *InsertIntoBucketImpl(const KeyT &Key, const LookupKeyT &Lookup, 531 BucketT *TheBucket) { 532 incrementEpoch(); 533 534 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of 535 // the buckets are empty (meaning that many are filled with tombstones), 536 // grow the table. 537 // 538 // The later case is tricky. For example, if we had one empty bucket with 539 // tons of tombstones, failing lookups (e.g. for insertion) would have to 540 // probe almost the entire table until it found the empty bucket. If the 541 // table completely filled with tombstones, no lookup would ever succeed, 542 // causing infinite loops in lookup. 543 unsigned NewNumEntries = getNumEntries() + 1; 544 unsigned NumBuckets = getNumBuckets(); 545 if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)) { 546 this->grow(NumBuckets * 2); 547 LookupBucketFor(Lookup, TheBucket); 548 NumBuckets = getNumBuckets(); 549 } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <= 550 NumBuckets/8)) { 551 this->grow(NumBuckets); 552 LookupBucketFor(Lookup, TheBucket); 553 } 554 assert(TheBucket); 555 556 // Only update the state after we've grown our bucket space appropriately 557 // so that when growing buckets we have self-consistent entry count. 558 incrementNumEntries(); 559 560 // If we are writing over a tombstone, remember this. 561 const KeyT EmptyKey = getEmptyKey(); 562 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey)) 563 decrementNumTombstones(); 564 565 return TheBucket; 566 } 567 568 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in 569 /// FoundBucket. If the bucket contains the key and a value, this returns 570 /// true, otherwise it returns a bucket with an empty marker or tombstone and 571 /// returns false. 572 template<typename LookupKeyT> 573 bool LookupBucketFor(const LookupKeyT &Val, 574 const BucketT *&FoundBucket) const { 575 const BucketT *BucketsPtr = getBuckets(); 576 const unsigned NumBuckets = getNumBuckets(); 577 578 if (NumBuckets == 0) { 579 FoundBucket = nullptr; 580 return false; 581 } 582 583 // FoundTombstone - Keep track of whether we find a tombstone while probing. 584 const BucketT *FoundTombstone = nullptr; 585 const KeyT EmptyKey = getEmptyKey(); 586 const KeyT TombstoneKey = getTombstoneKey(); 587 assert(!KeyInfoT::isEqual(Val, EmptyKey) && 588 !KeyInfoT::isEqual(Val, TombstoneKey) && 589 "Empty/Tombstone value shouldn't be inserted into map!"); 590 591 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1); 592 unsigned ProbeAmt = 1; 593 while (true) { 594 const BucketT *ThisBucket = BucketsPtr + BucketNo; 595 // Found Val's bucket? If so, return it. 596 if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))) { 597 FoundBucket = ThisBucket; 598 return true; 599 } 600 601 // If we found an empty bucket, the key doesn't exist in the set. 602 // Insert it and return the default value. 603 if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))) { 604 // If we've already seen a tombstone while probing, fill it in instead 605 // of the empty bucket we eventually probed to. 606 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket; 607 return false; 608 } 609 610 // If this is a tombstone, remember it. If Val ends up not in the map, we 611 // prefer to return it than something that would require more probing. 612 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) && 613 !FoundTombstone) 614 FoundTombstone = ThisBucket; // Remember the first tombstone found. 615 616 // Otherwise, it's a hash collision or a tombstone, continue quadratic 617 // probing. 618 BucketNo += ProbeAmt++; 619 BucketNo &= (NumBuckets-1); 620 } 621 } 622 623 template <typename LookupKeyT> 624 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) { 625 const BucketT *ConstFoundBucket; 626 bool Result = const_cast<const DenseMapBase *>(this) 627 ->LookupBucketFor(Val, ConstFoundBucket); 628 FoundBucket = const_cast<BucketT *>(ConstFoundBucket); 629 return Result; 630 } 631 632public: 633 /// Return the approximate size (in bytes) of the actual map. 634 /// This is just the raw memory used by DenseMap. 635 /// If entries are pointers to objects, the size of the referenced objects 636 /// are not included. 637 size_t getMemorySize() const { 638 return getNumBuckets() * sizeof(BucketT); 639 } 640}; 641 642template <typename KeyT, typename ValueT, 643 typename KeyInfoT = DenseMapInfo<KeyT>, 644 typename BucketT = detail::DenseMapPair<KeyT, ValueT>> 645class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>, 646 KeyT, ValueT, KeyInfoT, BucketT> { 647 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>; 648 649 // Lift some types from the dependent base class into this class for 650 // simplicity of referring to them. 651 using BaseT = DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>; 652 653 BucketT *Buckets; 654 unsigned NumEntries; 655 unsigned NumTombstones; 656 unsigned NumBuckets; 657 658public: 659 /// Create a DenseMap wth an optional \p InitialReserve that guarantee that 660 /// this number of elements can be inserted in the map without grow() 661 explicit DenseMap(unsigned InitialReserve = 0) { init(InitialReserve); } 662 663 DenseMap(const DenseMap &other) : BaseT() { 664 init(0); 665 copyFrom(other); 666 } 667 668 DenseMap(DenseMap &&other) : BaseT() { 669 init(0); 670 swap(other); 671 } 672 673 template<typename InputIt> 674 DenseMap(const InputIt &I, const InputIt &E) { 675 init(std::distance(I, E)); 676 this->insert(I, E); 677 } 678 679 ~DenseMap() { 680 this->destroyAll(); 681 operator delete(Buckets); 682 } 683 684 void swap(DenseMap& RHS) { 685 this->incrementEpoch(); 686 RHS.incrementEpoch(); 687 std::swap(Buckets, RHS.Buckets); 688 std::swap(NumEntries, RHS.NumEntries); 689 std::swap(NumTombstones, RHS.NumTombstones); 690 std::swap(NumBuckets, RHS.NumBuckets); 691 } 692 693 DenseMap& operator=(const DenseMap& other) { 694 if (&other != this) 695 copyFrom(other); 696 return *this; 697 } 698 699 DenseMap& operator=(DenseMap &&other) { 700 this->destroyAll(); 701 operator delete(Buckets); 702 init(0); 703 swap(other); 704 return *this; 705 } 706 707 void copyFrom(const DenseMap& other) { 708 this->destroyAll(); 709 operator delete(Buckets); 710 if (allocateBuckets(other.NumBuckets)) { 711 this->BaseT::copyFrom(other); 712 } else { 713 NumEntries = 0; 714 NumTombstones = 0; 715 } 716 } 717 718 void init(unsigned InitNumEntries) { 719 auto InitBuckets = BaseT::getMinBucketToReserveForEntries(InitNumEntries); 720 if (allocateBuckets(InitBuckets)) { 721 this->BaseT::initEmpty(); 722 } else { 723 NumEntries = 0; 724 NumTombstones = 0; 725 } 726 } 727 728 void grow(unsigned AtLeast) { 729 unsigned OldNumBuckets = NumBuckets; 730 BucketT *OldBuckets = Buckets; 731 732 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1)))); 733 assert(Buckets); 734 if (!OldBuckets) { 735 this->BaseT::initEmpty(); 736 return; 737 } 738 739 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets); 740 741 // Free the old table. 742 operator delete(OldBuckets); 743 } 744 745 void shrink_and_clear() { 746 unsigned OldNumEntries = NumEntries; 747 this->destroyAll(); 748 749 // Reduce the number of buckets. 750 unsigned NewNumBuckets = 0; 751 if (OldNumEntries) 752 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1)); 753 if (NewNumBuckets == NumBuckets) { 754 this->BaseT::initEmpty(); 755 return; 756 } 757 758 operator delete(Buckets); 759 init(NewNumBuckets); 760 } 761 762private: 763 unsigned getNumEntries() const { 764 return NumEntries; 765 } 766 767 void setNumEntries(unsigned Num) { 768 NumEntries = Num; 769 } 770 771 unsigned getNumTombstones() const { 772 return NumTombstones; 773 } 774 775 void setNumTombstones(unsigned Num) { 776 NumTombstones = Num; 777 } 778 779 BucketT *getBuckets() const { 780 return Buckets; 781 } 782 783 unsigned getNumBuckets() const { 784 return NumBuckets; 785 } 786 787 bool allocateBuckets(unsigned Num) { 788 NumBuckets = Num; 789 if (NumBuckets == 0) { 790 Buckets = nullptr; 791 return false; 792 } 793 794 Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets)); 795 return true; 796 } 797}; 798 799template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4, 800 typename KeyInfoT = DenseMapInfo<KeyT>, 801 typename BucketT = detail::DenseMapPair<KeyT, ValueT>> 802class SmallDenseMap 803 : public DenseMapBase< 804 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT, 805 ValueT, KeyInfoT, BucketT> { 806 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>; 807 808 // Lift some types from the dependent base class into this class for 809 // simplicity of referring to them. 810 using BaseT = DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>; 811 812 static_assert(isPowerOf2_64(InlineBuckets), 813 "InlineBuckets must be a power of 2."); 814 815 unsigned Small : 1; 816 unsigned NumEntries : 31; 817 unsigned NumTombstones; 818 819 struct LargeRep { 820 BucketT *Buckets; 821 unsigned NumBuckets; 822 }; 823 824 /// A "union" of an inline bucket array and the struct representing 825 /// a large bucket. This union will be discriminated by the 'Small' bit. 826 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage; 827 828public: 829 explicit SmallDenseMap(unsigned NumInitBuckets = 0) { 830 init(NumInitBuckets); 831 } 832 833 SmallDenseMap(const SmallDenseMap &other) : BaseT() { 834 init(0); 835 copyFrom(other); 836 } 837 838 SmallDenseMap(SmallDenseMap &&other) : BaseT() { 839 init(0); 840 swap(other); 841 } 842 843 template<typename InputIt> 844 SmallDenseMap(const InputIt &I, const InputIt &E) { 845 init(NextPowerOf2(std::distance(I, E))); 846 this->insert(I, E); 847 } 848 849 ~SmallDenseMap() { 850 this->destroyAll(); 851 deallocateBuckets(); 852 } 853 854 void swap(SmallDenseMap& RHS) { 855 unsigned TmpNumEntries = RHS.NumEntries; 856 RHS.NumEntries = NumEntries; 857 NumEntries = TmpNumEntries; 858 std::swap(NumTombstones, RHS.NumTombstones); 859 860 const KeyT EmptyKey = this->getEmptyKey(); 861 const KeyT TombstoneKey = this->getTombstoneKey(); 862 if (Small && RHS.Small) { 863 // If we're swapping inline bucket arrays, we have to cope with some of 864 // the tricky bits of DenseMap's storage system: the buckets are not 865 // fully initialized. Thus we swap every key, but we may have 866 // a one-directional move of the value. 867 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 868 BucketT *LHSB = &getInlineBuckets()[i], 869 *RHSB = &RHS.getInlineBuckets()[i]; 870 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) && 871 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey)); 872 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) && 873 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey)); 874 if (hasLHSValue && hasRHSValue) { 875 // Swap together if we can... 876 std::swap(*LHSB, *RHSB); 877 continue; 878 } 879 // Swap separately and handle any assymetry. 880 std::swap(LHSB->getFirst(), RHSB->getFirst()); 881 if (hasLHSValue) { 882 ::new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond())); 883 LHSB->getSecond().~ValueT(); 884 } else if (hasRHSValue) { 885 ::new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond())); 886 RHSB->getSecond().~ValueT(); 887 } 888 } 889 return; 890 } 891 if (!Small && !RHS.Small) { 892 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets); 893 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets); 894 return; 895 } 896 897 SmallDenseMap &SmallSide = Small ? *this : RHS; 898 SmallDenseMap &LargeSide = Small ? RHS : *this; 899 900 // First stash the large side's rep and move the small side across. 901 LargeRep TmpRep = std::move(*LargeSide.getLargeRep()); 902 LargeSide.getLargeRep()->~LargeRep(); 903 LargeSide.Small = true; 904 // This is similar to the standard move-from-old-buckets, but the bucket 905 // count hasn't actually rotated in this case. So we have to carefully 906 // move construct the keys and values into their new locations, but there 907 // is no need to re-hash things. 908 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) { 909 BucketT *NewB = &LargeSide.getInlineBuckets()[i], 910 *OldB = &SmallSide.getInlineBuckets()[i]; 911 ::new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst())); 912 OldB->getFirst().~KeyT(); 913 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) && 914 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) { 915 ::new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond())); 916 OldB->getSecond().~ValueT(); 917 } 918 } 919 920 // The hard part of moving the small buckets across is done, just move 921 // the TmpRep into its new home. 922 SmallSide.Small = false; 923 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep)); 924 } 925 926 SmallDenseMap& operator=(const SmallDenseMap& other) { 927 if (&other != this) 928 copyFrom(other); 929 return *this; 930 } 931 932 SmallDenseMap& operator=(SmallDenseMap &&other) { 933 this->destroyAll(); 934 deallocateBuckets(); 935 init(0); 936 swap(other); 937 return *this; 938 } 939 940 void copyFrom(const SmallDenseMap& other) { 941 this->destroyAll(); 942 deallocateBuckets(); 943 Small = true; 944 if (other.getNumBuckets() > InlineBuckets) { 945 Small = false; 946 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets())); 947 } 948 this->BaseT::copyFrom(other); 949 } 950 951 void init(unsigned InitBuckets) { 952 Small = true; 953 if (InitBuckets > InlineBuckets) { 954 Small = false; 955 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets)); 956 } 957 this->BaseT::initEmpty(); 958 } 959 960 void grow(unsigned AtLeast) { 961 if (AtLeast >= InlineBuckets) 962 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1)); 963 964 if (Small) { 965 if (AtLeast < InlineBuckets) 966 return; // Nothing to do. 967 968 // First move the inline buckets into a temporary storage. 969 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage; 970 BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer); 971 BucketT *TmpEnd = TmpBegin; 972 973 // Loop over the buckets, moving non-empty, non-tombstones into the 974 // temporary storage. Have the loop move the TmpEnd forward as it goes. 975 const KeyT EmptyKey = this->getEmptyKey(); 976 const KeyT TombstoneKey = this->getTombstoneKey(); 977 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) { 978 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) && 979 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) { 980 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets && 981 "Too many inline buckets!"); 982 ::new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst())); 983 ::new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond())); 984 ++TmpEnd; 985 P->getSecond().~ValueT(); 986 } 987 P->getFirst().~KeyT(); 988 } 989 990 // Now make this map use the large rep, and move all the entries back 991 // into it. 992 Small = false; 993 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 994 this->moveFromOldBuckets(TmpBegin, TmpEnd); 995 return; 996 } 997 998 LargeRep OldRep = std::move(*getLargeRep()); 999 getLargeRep()->~LargeRep(); 1000 if (AtLeast <= InlineBuckets) { 1001 Small = true; 1002 } else { 1003 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast)); 1004 } 1005 1006 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets); 1007 1008 // Free the old table. 1009 operator delete(OldRep.Buckets); 1010 } 1011 1012 void shrink_and_clear() { 1013 unsigned OldSize = this->size(); 1014 this->destroyAll(); 1015 1016 // Reduce the number of buckets. 1017 unsigned NewNumBuckets = 0; 1018 if (OldSize) { 1019 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1); 1020 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u) 1021 NewNumBuckets = 64; 1022 } 1023 if ((Small && NewNumBuckets <= InlineBuckets) || 1024 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) { 1025 this->BaseT::initEmpty(); 1026 return; 1027 } 1028 1029 deallocateBuckets(); 1030 init(NewNumBuckets); 1031 } 1032 1033private: 1034 unsigned getNumEntries() const { 1035 return NumEntries; 1036 } 1037 1038 void setNumEntries(unsigned Num) { 1039 // NumEntries is hardcoded to be 31 bits wide. 1040 assert(Num < (1U << 31) && "Cannot support more than 1<<31 entries"); 1041 NumEntries = Num; 1042 } 1043 1044 unsigned getNumTombstones() const { 1045 return NumTombstones; 1046 } 1047 1048 void setNumTombstones(unsigned Num) { 1049 NumTombstones = Num; 1050 } 1051 1052 const BucketT *getInlineBuckets() const { 1053 assert(Small); 1054 // Note that this cast does not violate aliasing rules as we assert that 1055 // the memory's dynamic type is the small, inline bucket buffer, and the 1056 // 'storage.buffer' static type is 'char *'. 1057 return reinterpret_cast<const BucketT *>(storage.buffer); 1058 } 1059 1060 BucketT *getInlineBuckets() { 1061 return const_cast<BucketT *>( 1062 const_cast<const SmallDenseMap *>(this)->getInlineBuckets()); 1063 } 1064 1065 const LargeRep *getLargeRep() const { 1066 assert(!Small); 1067 // Note, same rule about aliasing as with getInlineBuckets. 1068 return reinterpret_cast<const LargeRep *>(storage.buffer); 1069 } 1070 1071 LargeRep *getLargeRep() { 1072 return const_cast<LargeRep *>( 1073 const_cast<const SmallDenseMap *>(this)->getLargeRep()); 1074 } 1075 1076 const BucketT *getBuckets() const { 1077 return Small ? getInlineBuckets() : getLargeRep()->Buckets; 1078 } 1079 1080 BucketT *getBuckets() { 1081 return const_cast<BucketT *>( 1082 const_cast<const SmallDenseMap *>(this)->getBuckets()); 1083 } 1084 1085 unsigned getNumBuckets() const { 1086 return Small ? InlineBuckets : getLargeRep()->NumBuckets; 1087 } 1088 1089 void deallocateBuckets() { 1090 if (Small) 1091 return; 1092 1093 operator delete(getLargeRep()->Buckets); 1094 getLargeRep()->~LargeRep(); 1095 } 1096 1097 LargeRep allocateBuckets(unsigned Num) { 1098 assert(Num > InlineBuckets && "Must allocate more buckets than are inline"); 1099 LargeRep Rep = { 1100 static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num 1101 }; 1102 return Rep; 1103 } 1104}; 1105 1106template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket, 1107 bool IsConst> 1108class DenseMapIterator : DebugEpochBase::HandleBase { 1109 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>; 1110 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>; 1111 1112 using ConstIterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>; 1113 1114public: 1115 using difference_type = ptrdiff_t; 1116 using value_type = 1117 typename std::conditional<IsConst, const Bucket, Bucket>::type; 1118 using pointer = value_type *; 1119 using reference = value_type &; 1120 using iterator_category = std::forward_iterator_tag; 1121 1122private: 1123 pointer Ptr = nullptr; 1124 pointer End = nullptr; 1125 1126public: 1127 DenseMapIterator() = default; 1128 1129 DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch, 1130 bool NoAdvance = false) 1131 : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) { 1132 assert(isHandleInSync() && "invalid construction!"); 1133 1134 if (NoAdvance) return; 1135 if (shouldReverseIterate<KeyT>()) { 1136 RetreatPastEmptyBuckets(); 1137 return; 1138 } 1139 AdvancePastEmptyBuckets(); 1140 } 1141 1142 // Converting ctor from non-const iterators to const iterators. SFINAE'd out 1143 // for const iterator destinations so it doesn't end up as a user defined copy 1144 // constructor. 1145 template <bool IsConstSrc, 1146 typename = typename std::enable_if<!IsConstSrc && IsConst>::type> 1147 DenseMapIterator( 1148 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I) 1149 : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {} 1150 1151 reference operator*() const { 1152 assert(isHandleInSync() && "invalid iterator access!"); 1153 if (shouldReverseIterate<KeyT>()) 1154 return Ptr[-1]; 1155 return *Ptr; 1156 } 1157 pointer operator->() const { 1158 assert(isHandleInSync() && "invalid iterator access!"); 1159 if (shouldReverseIterate<KeyT>()) 1160 return &(Ptr[-1]); 1161 return Ptr; 1162 } 1163 1164 bool operator==(const ConstIterator &RHS) const { 1165 assert((!Ptr || isHandleInSync()) && "handle not in sync!"); 1166 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!"); 1167 assert(getEpochAddress() == RHS.getEpochAddress() && 1168 "comparing incomparable iterators!"); 1169 return Ptr == RHS.Ptr; 1170 } 1171 bool operator!=(const ConstIterator &RHS) const { 1172 assert((!Ptr || isHandleInSync()) && "handle not in sync!"); 1173 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!"); 1174 assert(getEpochAddress() == RHS.getEpochAddress() && 1175 "comparing incomparable iterators!"); 1176 return Ptr != RHS.Ptr; 1177 } 1178 1179 inline DenseMapIterator& operator++() { // Preincrement 1180 assert(isHandleInSync() && "invalid iterator access!"); 1181 if (shouldReverseIterate<KeyT>()) { 1182 --Ptr; 1183 RetreatPastEmptyBuckets(); 1184 return *this; 1185 } 1186 ++Ptr; 1187 AdvancePastEmptyBuckets(); 1188 return *this; 1189 } 1190 DenseMapIterator operator++(int) { // Postincrement 1191 assert(isHandleInSync() && "invalid iterator access!"); 1192 DenseMapIterator tmp = *this; ++*this; return tmp; 1193 } 1194 1195private: 1196 void AdvancePastEmptyBuckets() { 1197 assert(Ptr <= End); 1198 const KeyT Empty = KeyInfoT::getEmptyKey(); 1199 const KeyT Tombstone = KeyInfoT::getTombstoneKey(); 1200 1201 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) || 1202 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone))) 1203 ++Ptr; 1204 } 1205 1206 void RetreatPastEmptyBuckets() { 1207 assert(Ptr >= End); 1208 const KeyT Empty = KeyInfoT::getEmptyKey(); 1209 const KeyT Tombstone = KeyInfoT::getTombstoneKey(); 1210 1211 while (Ptr != End && (KeyInfoT::isEqual(Ptr[-1].getFirst(), Empty) || 1212 KeyInfoT::isEqual(Ptr[-1].getFirst(), Tombstone))) 1213 --Ptr; 1214 } 1215}; 1216 1217template<typename KeyT, typename ValueT, typename KeyInfoT> 1218static inline size_t 1219capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) { 1220 return X.getMemorySize(); 1221} 1222 1223} // end namespace llvm 1224 1225#endif // LLVM_ADT_DENSEMAP_H 1226