1 //===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the BitVector class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_ADT_BITVECTOR_H 14 #define LLVM_ADT_BITVECTOR_H 15 16 #include "llvm/ADT/ArrayRef.h" 17 #include "llvm/ADT/DenseMapInfo.h" 18 #include "llvm/ADT/iterator_range.h" 19 #include "llvm/Support/MathExtras.h" 20 #include <algorithm> 21 #include <cassert> 22 #include <climits> 23 #include <cstdint> 24 #include <cstdlib> 25 #include <cstring> 26 #include <utility> 27 28 namespace llvm { 29 30 /// ForwardIterator for the bits that are set. 31 /// Iterators get invalidated when resize / reserve is called. 32 template <typename BitVectorT> class const_set_bits_iterator_impl { 33 const BitVectorT &Parent; 34 int Current = 0; 35 36 void advance() { 37 assert(Current != -1 && "Trying to advance past end."); 38 Current = Parent.find_next(Current); 39 } 40 41 public: 42 const_set_bits_iterator_impl(const BitVectorT &Parent, int Current) 43 : Parent(Parent), Current(Current) {} 44 explicit const_set_bits_iterator_impl(const BitVectorT &Parent) 45 : const_set_bits_iterator_impl(Parent, Parent.find_first()) {} 46 const_set_bits_iterator_impl(const const_set_bits_iterator_impl &) = default; 47 48 const_set_bits_iterator_impl operator++(int) { 49 auto Prev = *this; 50 advance(); 51 return Prev; 52 } 53 54 const_set_bits_iterator_impl &operator++() { 55 advance(); 56 return *this; 57 } 58 59 unsigned operator*() const { return Current; } 60 61 bool operator==(const const_set_bits_iterator_impl &Other) const { 62 assert(&Parent == &Other.Parent && 63 "Comparing iterators from different BitVectors"); 64 return Current == Other.Current; 65 } 66 67 bool operator!=(const const_set_bits_iterator_impl &Other) const { 68 assert(&Parent == &Other.Parent && 69 "Comparing iterators from different BitVectors"); 70 return Current != Other.Current; 71 } 72 }; 73 74 class BitVector { 75 typedef uintptr_t BitWord; 76 77 enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT }; 78 79 static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32, 80 "Unsupported word size"); 81 82 MutableArrayRef<BitWord> Bits; // Actual bits. 83 unsigned Size; // Size of bitvector in bits. 84 85 public: 86 typedef unsigned size_type; 87 // Encapsulation of a single bit. 88 class reference { 89 friend class BitVector; 90 91 BitWord *WordRef; 92 unsigned BitPos; 93 94 public: 95 reference(BitVector &b, unsigned Idx) { 96 WordRef = &b.Bits[Idx / BITWORD_SIZE]; 97 BitPos = Idx % BITWORD_SIZE; 98 } 99 100 reference() = delete; 101 reference(const reference&) = default; 102 103 reference &operator=(reference t) { 104 *this = bool(t); 105 return *this; 106 } 107 108 reference& operator=(bool t) { 109 if (t) 110 *WordRef |= BitWord(1) << BitPos; 111 else 112 *WordRef &= ~(BitWord(1) << BitPos); 113 return *this; 114 } 115 116 operator bool() const { 117 return ((*WordRef) & (BitWord(1) << BitPos)) != 0; 118 } 119 }; 120 121 typedef const_set_bits_iterator_impl<BitVector> const_set_bits_iterator; 122 typedef const_set_bits_iterator set_iterator; 123 124 const_set_bits_iterator set_bits_begin() const { 125 return const_set_bits_iterator(*this); 126 } 127 const_set_bits_iterator set_bits_end() const { 128 return const_set_bits_iterator(*this, -1); 129 } 130 iterator_range<const_set_bits_iterator> set_bits() const { 131 return make_range(set_bits_begin(), set_bits_end()); 132 } 133 134 /// BitVector default ctor - Creates an empty bitvector. 135 BitVector() : Size(0) {} 136 137 /// BitVector ctor - Creates a bitvector of specified number of bits. All 138 /// bits are initialized to the specified value. 139 explicit BitVector(unsigned s, bool t = false) : Size(s) { 140 size_t Capacity = NumBitWords(s); 141 Bits = allocate(Capacity); 142 init_words(Bits, t); 143 if (t) 144 clear_unused_bits(); 145 } 146 147 /// BitVector copy ctor. 148 BitVector(const BitVector &RHS) : Size(RHS.size()) { 149 if (Size == 0) { 150 Bits = MutableArrayRef<BitWord>(); 151 return; 152 } 153 154 size_t Capacity = NumBitWords(RHS.size()); 155 Bits = allocate(Capacity); 156 std::memcpy(Bits.data(), RHS.Bits.data(), Capacity * sizeof(BitWord)); 157 } 158 159 BitVector(BitVector &&RHS) : Bits(RHS.Bits), Size(RHS.Size) { 160 RHS.Bits = MutableArrayRef<BitWord>(); 161 RHS.Size = 0; 162 } 163 164 ~BitVector() { std::free(Bits.data()); } 165 166 /// empty - Tests whether there are no bits in this bitvector. 167 bool empty() const { return Size == 0; } 168 169 /// size - Returns the number of bits in this bitvector. 170 size_type size() const { return Size; } 171 172 /// count - Returns the number of bits which are set. 173 size_type count() const { 174 unsigned NumBits = 0; 175 for (unsigned i = 0; i < NumBitWords(size()); ++i) 176 NumBits += countPopulation(Bits[i]); 177 return NumBits; 178 } 179 180 /// any - Returns true if any bit is set. 181 bool any() const { 182 for (unsigned i = 0; i < NumBitWords(size()); ++i) 183 if (Bits[i] != 0) 184 return true; 185 return false; 186 } 187 188 /// all - Returns true if all bits are set. 189 bool all() const { 190 for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i) 191 if (Bits[i] != ~BitWord(0)) 192 return false; 193 194 // If bits remain check that they are ones. The unused bits are always zero. 195 if (unsigned Remainder = Size % BITWORD_SIZE) 196 return Bits[Size / BITWORD_SIZE] == (BitWord(1) << Remainder) - 1; 197 198 return true; 199 } 200 201 /// none - Returns true if none of the bits are set. 202 bool none() const { 203 return !any(); 204 } 205 206 /// find_first_in - Returns the index of the first set / unset bit, 207 /// depending on \p Set, in the range [Begin, End). 208 /// Returns -1 if all bits in the range are unset / set. 209 int find_first_in(unsigned Begin, unsigned End, bool Set = true) const { 210 assert(Begin <= End && End <= Size); 211 if (Begin == End) 212 return -1; 213 214 unsigned FirstWord = Begin / BITWORD_SIZE; 215 unsigned LastWord = (End - 1) / BITWORD_SIZE; 216 217 // Check subsequent words. 218 // The code below is based on search for the first _set_ bit. If 219 // we're searching for the first _unset_, we just take the 220 // complement of each word before we use it and apply 221 // the same method. 222 for (unsigned i = FirstWord; i <= LastWord; ++i) { 223 BitWord Copy = Bits[i]; 224 if (!Set) 225 Copy = ~Copy; 226 227 if (i == FirstWord) { 228 unsigned FirstBit = Begin % BITWORD_SIZE; 229 Copy &= maskTrailingZeros<BitWord>(FirstBit); 230 } 231 232 if (i == LastWord) { 233 unsigned LastBit = (End - 1) % BITWORD_SIZE; 234 Copy &= maskTrailingOnes<BitWord>(LastBit + 1); 235 } 236 if (Copy != 0) 237 return i * BITWORD_SIZE + countTrailingZeros(Copy); 238 } 239 return -1; 240 } 241 242 /// find_last_in - Returns the index of the last set bit in the range 243 /// [Begin, End). Returns -1 if all bits in the range are unset. 244 int find_last_in(unsigned Begin, unsigned End) const { 245 assert(Begin <= End && End <= Size); 246 if (Begin == End) 247 return -1; 248 249 unsigned LastWord = (End - 1) / BITWORD_SIZE; 250 unsigned FirstWord = Begin / BITWORD_SIZE; 251 252 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) { 253 unsigned CurrentWord = i - 1; 254 255 BitWord Copy = Bits[CurrentWord]; 256 if (CurrentWord == LastWord) { 257 unsigned LastBit = (End - 1) % BITWORD_SIZE; 258 Copy &= maskTrailingOnes<BitWord>(LastBit + 1); 259 } 260 261 if (CurrentWord == FirstWord) { 262 unsigned FirstBit = Begin % BITWORD_SIZE; 263 Copy &= maskTrailingZeros<BitWord>(FirstBit); 264 } 265 266 if (Copy != 0) 267 return (CurrentWord + 1) * BITWORD_SIZE - countLeadingZeros(Copy) - 1; 268 } 269 270 return -1; 271 } 272 273 /// find_first_unset_in - Returns the index of the first unset bit in the 274 /// range [Begin, End). Returns -1 if all bits in the range are set. 275 int find_first_unset_in(unsigned Begin, unsigned End) const { 276 return find_first_in(Begin, End, /* Set = */ false); 277 } 278 279 /// find_last_unset_in - Returns the index of the last unset bit in the 280 /// range [Begin, End). Returns -1 if all bits in the range are set. 281 int find_last_unset_in(unsigned Begin, unsigned End) const { 282 assert(Begin <= End && End <= Size); 283 if (Begin == End) 284 return -1; 285 286 unsigned LastWord = (End - 1) / BITWORD_SIZE; 287 unsigned FirstWord = Begin / BITWORD_SIZE; 288 289 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) { 290 unsigned CurrentWord = i - 1; 291 292 BitWord Copy = Bits[CurrentWord]; 293 if (CurrentWord == LastWord) { 294 unsigned LastBit = (End - 1) % BITWORD_SIZE; 295 Copy |= maskTrailingZeros<BitWord>(LastBit + 1); 296 } 297 298 if (CurrentWord == FirstWord) { 299 unsigned FirstBit = Begin % BITWORD_SIZE; 300 Copy |= maskTrailingOnes<BitWord>(FirstBit); 301 } 302 303 if (Copy != ~BitWord(0)) { 304 unsigned Result = 305 (CurrentWord + 1) * BITWORD_SIZE - countLeadingOnes(Copy) - 1; 306 return Result < Size ? Result : -1; 307 } 308 } 309 return -1; 310 } 311 312 /// find_first - Returns the index of the first set bit, -1 if none 313 /// of the bits are set. 314 int find_first() const { return find_first_in(0, Size); } 315 316 /// find_last - Returns the index of the last set bit, -1 if none of the bits 317 /// are set. 318 int find_last() const { return find_last_in(0, Size); } 319 320 /// find_next - Returns the index of the next set bit following the 321 /// "Prev" bit. Returns -1 if the next set bit is not found. 322 int find_next(unsigned Prev) const { return find_first_in(Prev + 1, Size); } 323 324 /// find_prev - Returns the index of the first set bit that precedes the 325 /// the bit at \p PriorTo. Returns -1 if all previous bits are unset. 326 int find_prev(unsigned PriorTo) const { return find_last_in(0, PriorTo); } 327 328 /// find_first_unset - Returns the index of the first unset bit, -1 if all 329 /// of the bits are set. 330 int find_first_unset() const { return find_first_unset_in(0, Size); } 331 332 /// find_next_unset - Returns the index of the next unset bit following the 333 /// "Prev" bit. Returns -1 if all remaining bits are set. 334 int find_next_unset(unsigned Prev) const { 335 return find_first_unset_in(Prev + 1, Size); 336 } 337 338 /// find_last_unset - Returns the index of the last unset bit, -1 if all of 339 /// the bits are set. 340 int find_last_unset() const { return find_last_unset_in(0, Size); } 341 342 /// find_prev_unset - Returns the index of the first unset bit that precedes 343 /// the bit at \p PriorTo. Returns -1 if all previous bits are set. 344 int find_prev_unset(unsigned PriorTo) { 345 return find_last_unset_in(0, PriorTo); 346 } 347 348 /// clear - Removes all bits from the bitvector. Does not change capacity. 349 void clear() { 350 Size = 0; 351 } 352 353 /// resize - Grow or shrink the bitvector. 354 void resize(unsigned N, bool t = false) { 355 if (N > getBitCapacity()) { 356 unsigned OldCapacity = Bits.size(); 357 grow(N); 358 init_words(Bits.drop_front(OldCapacity), t); 359 } 360 361 // Set any old unused bits that are now included in the BitVector. This 362 // may set bits that are not included in the new vector, but we will clear 363 // them back out below. 364 if (N > Size) 365 set_unused_bits(t); 366 367 // Update the size, and clear out any bits that are now unused 368 unsigned OldSize = Size; 369 Size = N; 370 if (t || N < OldSize) 371 clear_unused_bits(); 372 } 373 374 void reserve(unsigned N) { 375 if (N > getBitCapacity()) 376 grow(N); 377 } 378 379 // Set, reset, flip 380 BitVector &set() { 381 init_words(Bits, true); 382 clear_unused_bits(); 383 return *this; 384 } 385 386 BitVector &set(unsigned Idx) { 387 assert(Bits.data() && "Bits never allocated"); 388 Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE); 389 return *this; 390 } 391 392 /// set - Efficiently set a range of bits in [I, E) 393 BitVector &set(unsigned I, unsigned E) { 394 assert(I <= E && "Attempted to set backwards range!"); 395 assert(E <= size() && "Attempted to set out-of-bounds range!"); 396 397 if (I == E) return *this; 398 399 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 400 BitWord EMask = BitWord(1) << (E % BITWORD_SIZE); 401 BitWord IMask = BitWord(1) << (I % BITWORD_SIZE); 402 BitWord Mask = EMask - IMask; 403 Bits[I / BITWORD_SIZE] |= Mask; 404 return *this; 405 } 406 407 BitWord PrefixMask = ~BitWord(0) << (I % BITWORD_SIZE); 408 Bits[I / BITWORD_SIZE] |= PrefixMask; 409 I = alignTo(I, BITWORD_SIZE); 410 411 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 412 Bits[I / BITWORD_SIZE] = ~BitWord(0); 413 414 BitWord PostfixMask = (BitWord(1) << (E % BITWORD_SIZE)) - 1; 415 if (I < E) 416 Bits[I / BITWORD_SIZE] |= PostfixMask; 417 418 return *this; 419 } 420 421 BitVector &reset() { 422 init_words(Bits, false); 423 return *this; 424 } 425 426 BitVector &reset(unsigned Idx) { 427 Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE)); 428 return *this; 429 } 430 431 /// reset - Efficiently reset a range of bits in [I, E) 432 BitVector &reset(unsigned I, unsigned E) { 433 assert(I <= E && "Attempted to reset backwards range!"); 434 assert(E <= size() && "Attempted to reset out-of-bounds range!"); 435 436 if (I == E) return *this; 437 438 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 439 BitWord EMask = BitWord(1) << (E % BITWORD_SIZE); 440 BitWord IMask = BitWord(1) << (I % BITWORD_SIZE); 441 BitWord Mask = EMask - IMask; 442 Bits[I / BITWORD_SIZE] &= ~Mask; 443 return *this; 444 } 445 446 BitWord PrefixMask = ~BitWord(0) << (I % BITWORD_SIZE); 447 Bits[I / BITWORD_SIZE] &= ~PrefixMask; 448 I = alignTo(I, BITWORD_SIZE); 449 450 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 451 Bits[I / BITWORD_SIZE] = BitWord(0); 452 453 BitWord PostfixMask = (BitWord(1) << (E % BITWORD_SIZE)) - 1; 454 if (I < E) 455 Bits[I / BITWORD_SIZE] &= ~PostfixMask; 456 457 return *this; 458 } 459 460 BitVector &flip() { 461 for (unsigned i = 0; i < NumBitWords(size()); ++i) 462 Bits[i] = ~Bits[i]; 463 clear_unused_bits(); 464 return *this; 465 } 466 467 BitVector &flip(unsigned Idx) { 468 Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE); 469 return *this; 470 } 471 472 // Indexing. 473 reference operator[](unsigned Idx) { 474 assert (Idx < Size && "Out-of-bounds Bit access."); 475 return reference(*this, Idx); 476 } 477 478 bool operator[](unsigned Idx) const { 479 assert (Idx < Size && "Out-of-bounds Bit access."); 480 BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE); 481 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0; 482 } 483 484 bool test(unsigned Idx) const { 485 return (*this)[Idx]; 486 } 487 488 // Push single bit to end of vector. 489 void push_back(bool Val) { 490 unsigned OldSize = Size; 491 unsigned NewSize = Size + 1; 492 493 // Resize, which will insert zeros. 494 // If we already fit then the unused bits will be already zero. 495 if (NewSize > getBitCapacity()) 496 resize(NewSize, false); 497 else 498 Size = NewSize; 499 500 // If true, set single bit. 501 if (Val) 502 set(OldSize); 503 } 504 505 /// Test if any common bits are set. 506 bool anyCommon(const BitVector &RHS) const { 507 unsigned ThisWords = NumBitWords(size()); 508 unsigned RHSWords = NumBitWords(RHS.size()); 509 for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i) 510 if (Bits[i] & RHS.Bits[i]) 511 return true; 512 return false; 513 } 514 515 // Comparison operators. 516 bool operator==(const BitVector &RHS) const { 517 if (size() != RHS.size()) 518 return false; 519 unsigned NumWords = NumBitWords(size()); 520 return Bits.take_front(NumWords) == RHS.Bits.take_front(NumWords); 521 } 522 523 bool operator!=(const BitVector &RHS) const { 524 return !(*this == RHS); 525 } 526 527 /// Intersection, union, disjoint union. 528 BitVector &operator&=(const BitVector &RHS) { 529 unsigned ThisWords = NumBitWords(size()); 530 unsigned RHSWords = NumBitWords(RHS.size()); 531 unsigned i; 532 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 533 Bits[i] &= RHS.Bits[i]; 534 535 // Any bits that are just in this bitvector become zero, because they aren't 536 // in the RHS bit vector. Any words only in RHS are ignored because they 537 // are already zero in the LHS. 538 for (; i != ThisWords; ++i) 539 Bits[i] = 0; 540 541 return *this; 542 } 543 544 /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS. 545 BitVector &reset(const BitVector &RHS) { 546 unsigned ThisWords = NumBitWords(size()); 547 unsigned RHSWords = NumBitWords(RHS.size()); 548 unsigned i; 549 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 550 Bits[i] &= ~RHS.Bits[i]; 551 return *this; 552 } 553 554 /// test - Check if (This - RHS) is zero. 555 /// This is the same as reset(RHS) and any(). 556 bool test(const BitVector &RHS) const { 557 unsigned ThisWords = NumBitWords(size()); 558 unsigned RHSWords = NumBitWords(RHS.size()); 559 unsigned i; 560 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 561 if ((Bits[i] & ~RHS.Bits[i]) != 0) 562 return true; 563 564 for (; i != ThisWords ; ++i) 565 if (Bits[i] != 0) 566 return true; 567 568 return false; 569 } 570 571 BitVector &operator|=(const BitVector &RHS) { 572 if (size() < RHS.size()) 573 resize(RHS.size()); 574 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 575 Bits[i] |= RHS.Bits[i]; 576 return *this; 577 } 578 579 BitVector &operator^=(const BitVector &RHS) { 580 if (size() < RHS.size()) 581 resize(RHS.size()); 582 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 583 Bits[i] ^= RHS.Bits[i]; 584 return *this; 585 } 586 587 BitVector &operator>>=(unsigned N) { 588 assert(N <= Size); 589 if (LLVM_UNLIKELY(empty() || N == 0)) 590 return *this; 591 592 unsigned NumWords = NumBitWords(Size); 593 assert(NumWords >= 1); 594 595 wordShr(N / BITWORD_SIZE); 596 597 unsigned BitDistance = N % BITWORD_SIZE; 598 if (BitDistance == 0) 599 return *this; 600 601 // When the shift size is not a multiple of the word size, then we have 602 // a tricky situation where each word in succession needs to extract some 603 // of the bits from the next word and or them into this word while 604 // shifting this word to make room for the new bits. This has to be done 605 // for every word in the array. 606 607 // Since we're shifting each word right, some bits will fall off the end 608 // of each word to the right, and empty space will be created on the left. 609 // The final word in the array will lose bits permanently, so starting at 610 // the beginning, work forwards shifting each word to the right, and 611 // OR'ing in the bits from the end of the next word to the beginning of 612 // the current word. 613 614 // Example: 615 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting right 616 // by 4 bits. 617 // Step 1: Word[0] >>= 4 ; 0x0ABBCCDD 618 // Step 2: Word[0] |= 0x10000000 ; 0x1ABBCCDD 619 // Step 3: Word[1] >>= 4 ; 0x0EEFF001 620 // Step 4: Word[1] |= 0x50000000 ; 0x5EEFF001 621 // Step 5: Word[2] >>= 4 ; 0x02334455 622 // Result: { 0x1ABBCCDD, 0x5EEFF001, 0x02334455 } 623 const BitWord Mask = maskTrailingOnes<BitWord>(BitDistance); 624 const unsigned LSH = BITWORD_SIZE - BitDistance; 625 626 for (unsigned I = 0; I < NumWords - 1; ++I) { 627 Bits[I] >>= BitDistance; 628 Bits[I] |= (Bits[I + 1] & Mask) << LSH; 629 } 630 631 Bits[NumWords - 1] >>= BitDistance; 632 633 return *this; 634 } 635 636 BitVector &operator<<=(unsigned N) { 637 assert(N <= Size); 638 if (LLVM_UNLIKELY(empty() || N == 0)) 639 return *this; 640 641 unsigned NumWords = NumBitWords(Size); 642 assert(NumWords >= 1); 643 644 wordShl(N / BITWORD_SIZE); 645 646 unsigned BitDistance = N % BITWORD_SIZE; 647 if (BitDistance == 0) 648 return *this; 649 650 // When the shift size is not a multiple of the word size, then we have 651 // a tricky situation where each word in succession needs to extract some 652 // of the bits from the previous word and or them into this word while 653 // shifting this word to make room for the new bits. This has to be done 654 // for every word in the array. This is similar to the algorithm outlined 655 // in operator>>=, but backwards. 656 657 // Since we're shifting each word left, some bits will fall off the end 658 // of each word to the left, and empty space will be created on the right. 659 // The first word in the array will lose bits permanently, so starting at 660 // the end, work backwards shifting each word to the left, and OR'ing 661 // in the bits from the end of the next word to the beginning of the 662 // current word. 663 664 // Example: 665 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting left 666 // by 4 bits. 667 // Step 1: Word[2] <<= 4 ; 0x23344550 668 // Step 2: Word[2] |= 0x0000000E ; 0x2334455E 669 // Step 3: Word[1] <<= 4 ; 0xEFF00110 670 // Step 4: Word[1] |= 0x0000000A ; 0xEFF0011A 671 // Step 5: Word[0] <<= 4 ; 0xABBCCDD0 672 // Result: { 0xABBCCDD0, 0xEFF0011A, 0x2334455E } 673 const BitWord Mask = maskLeadingOnes<BitWord>(BitDistance); 674 const unsigned RSH = BITWORD_SIZE - BitDistance; 675 676 for (int I = NumWords - 1; I > 0; --I) { 677 Bits[I] <<= BitDistance; 678 Bits[I] |= (Bits[I - 1] & Mask) >> RSH; 679 } 680 Bits[0] <<= BitDistance; 681 clear_unused_bits(); 682 683 return *this; 684 } 685 686 // Assignment operator. 687 const BitVector &operator=(const BitVector &RHS) { 688 if (this == &RHS) return *this; 689 690 Size = RHS.size(); 691 692 // Handle tombstone when the BitVector is a key of a DenseHash. 693 if (RHS.isInvalid()) { 694 std::free(Bits.data()); 695 Bits = None; 696 return *this; 697 } 698 699 unsigned RHSWords = NumBitWords(Size); 700 if (Size <= getBitCapacity()) { 701 if (Size) 702 std::memcpy(Bits.data(), RHS.Bits.data(), RHSWords * sizeof(BitWord)); 703 clear_unused_bits(); 704 return *this; 705 } 706 707 // Grow the bitvector to have enough elements. 708 unsigned NewCapacity = RHSWords; 709 assert(NewCapacity > 0 && "negative capacity?"); 710 auto NewBits = allocate(NewCapacity); 711 std::memcpy(NewBits.data(), RHS.Bits.data(), NewCapacity * sizeof(BitWord)); 712 713 // Destroy the old bits. 714 std::free(Bits.data()); 715 Bits = NewBits; 716 717 return *this; 718 } 719 720 const BitVector &operator=(BitVector &&RHS) { 721 if (this == &RHS) return *this; 722 723 std::free(Bits.data()); 724 Bits = RHS.Bits; 725 Size = RHS.Size; 726 727 RHS.Bits = MutableArrayRef<BitWord>(); 728 RHS.Size = 0; 729 730 return *this; 731 } 732 733 void swap(BitVector &RHS) { 734 std::swap(Bits, RHS.Bits); 735 std::swap(Size, RHS.Size); 736 } 737 738 void invalid() { 739 assert(!Size && Bits.empty()); 740 Size = (unsigned)-1; 741 } 742 bool isInvalid() const { return Size == (unsigned)-1; } 743 744 ArrayRef<BitWord> getData() const { 745 return Bits.take_front(NumBitWords(size())); 746 } 747 748 //===--------------------------------------------------------------------===// 749 // Portable bit mask operations. 750 //===--------------------------------------------------------------------===// 751 // 752 // These methods all operate on arrays of uint32_t, each holding 32 bits. The 753 // fixed word size makes it easier to work with literal bit vector constants 754 // in portable code. 755 // 756 // The LSB in each word is the lowest numbered bit. The size of a portable 757 // bit mask is always a whole multiple of 32 bits. If no bit mask size is 758 // given, the bit mask is assumed to cover the entire BitVector. 759 760 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize. 761 /// This computes "*this |= Mask". 762 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 763 applyMask<true, false>(Mask, MaskWords); 764 } 765 766 /// clearBitsInMask - Clear any bits in this vector that are set in Mask. 767 /// Don't resize. This computes "*this &= ~Mask". 768 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 769 applyMask<false, false>(Mask, MaskWords); 770 } 771 772 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask. 773 /// Don't resize. This computes "*this |= ~Mask". 774 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 775 applyMask<true, true>(Mask, MaskWords); 776 } 777 778 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask. 779 /// Don't resize. This computes "*this &= Mask". 780 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 781 applyMask<false, true>(Mask, MaskWords); 782 } 783 784 private: 785 /// Perform a logical left shift of \p Count words by moving everything 786 /// \p Count words to the right in memory. 787 /// 788 /// While confusing, words are stored from least significant at Bits[0] to 789 /// most significant at Bits[NumWords-1]. A logical shift left, however, 790 /// moves the current least significant bit to a higher logical index, and 791 /// fills the previous least significant bits with 0. Thus, we actually 792 /// need to move the bytes of the memory to the right, not to the left. 793 /// Example: 794 /// Words = [0xBBBBAAAA, 0xDDDDFFFF, 0x00000000, 0xDDDD0000] 795 /// represents a BitVector where 0xBBBBAAAA contain the least significant 796 /// bits. So if we want to shift the BitVector left by 2 words, we need to 797 /// turn this into 0x00000000 0x00000000 0xBBBBAAAA 0xDDDDFFFF by using a 798 /// memmove which moves right, not left. 799 void wordShl(uint32_t Count) { 800 if (Count == 0) 801 return; 802 803 uint32_t NumWords = NumBitWords(Size); 804 805 auto Src = Bits.take_front(NumWords).drop_back(Count); 806 auto Dest = Bits.take_front(NumWords).drop_front(Count); 807 808 // Since we always move Word-sized chunks of data with src and dest both 809 // aligned to a word-boundary, we don't need to worry about endianness 810 // here. 811 std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord)); 812 std::memset(Bits.data(), 0, Count * sizeof(BitWord)); 813 clear_unused_bits(); 814 } 815 816 /// Perform a logical right shift of \p Count words by moving those 817 /// words to the left in memory. See wordShl for more information. 818 /// 819 void wordShr(uint32_t Count) { 820 if (Count == 0) 821 return; 822 823 uint32_t NumWords = NumBitWords(Size); 824 825 auto Src = Bits.take_front(NumWords).drop_front(Count); 826 auto Dest = Bits.take_front(NumWords).drop_back(Count); 827 assert(Dest.size() == Src.size()); 828 829 std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord)); 830 std::memset(Dest.end(), 0, Count * sizeof(BitWord)); 831 } 832 833 MutableArrayRef<BitWord> allocate(size_t NumWords) { 834 BitWord *RawBits = static_cast<BitWord *>( 835 safe_malloc(NumWords * sizeof(BitWord))); 836 return MutableArrayRef<BitWord>(RawBits, NumWords); 837 } 838 839 int next_unset_in_word(int WordIndex, BitWord Word) const { 840 unsigned Result = WordIndex * BITWORD_SIZE + countTrailingOnes(Word); 841 return Result < size() ? Result : -1; 842 } 843 844 unsigned NumBitWords(unsigned S) const { 845 return (S + BITWORD_SIZE-1) / BITWORD_SIZE; 846 } 847 848 // Set the unused bits in the high words. 849 void set_unused_bits(bool t = true) { 850 // Set high words first. 851 unsigned UsedWords = NumBitWords(Size); 852 if (Bits.size() > UsedWords) 853 init_words(Bits.drop_front(UsedWords), t); 854 855 // Then set any stray high bits of the last used word. 856 unsigned ExtraBits = Size % BITWORD_SIZE; 857 if (ExtraBits) { 858 BitWord ExtraBitMask = ~BitWord(0) << ExtraBits; 859 if (t) 860 Bits[UsedWords-1] |= ExtraBitMask; 861 else 862 Bits[UsedWords-1] &= ~ExtraBitMask; 863 } 864 } 865 866 // Clear the unused bits in the high words. 867 void clear_unused_bits() { 868 set_unused_bits(false); 869 } 870 871 void grow(unsigned NewSize) { 872 size_t NewCapacity = std::max<size_t>(NumBitWords(NewSize), Bits.size() * 2); 873 assert(NewCapacity > 0 && "realloc-ing zero space"); 874 BitWord *NewBits = static_cast<BitWord *>( 875 safe_realloc(Bits.data(), NewCapacity * sizeof(BitWord))); 876 Bits = MutableArrayRef<BitWord>(NewBits, NewCapacity); 877 clear_unused_bits(); 878 } 879 880 void init_words(MutableArrayRef<BitWord> B, bool t) { 881 if (B.size() > 0) 882 memset(B.data(), 0 - (int)t, B.size() * sizeof(BitWord)); 883 } 884 885 template<bool AddBits, bool InvertMask> 886 void applyMask(const uint32_t *Mask, unsigned MaskWords) { 887 static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size."); 888 MaskWords = std::min(MaskWords, (size() + 31) / 32); 889 const unsigned Scale = BITWORD_SIZE / 32; 890 unsigned i; 891 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) { 892 BitWord BW = Bits[i]; 893 // This inner loop should unroll completely when BITWORD_SIZE > 32. 894 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) { 895 uint32_t M = *Mask++; 896 if (InvertMask) M = ~M; 897 if (AddBits) BW |= BitWord(M) << b; 898 else BW &= ~(BitWord(M) << b); 899 } 900 Bits[i] = BW; 901 } 902 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) { 903 uint32_t M = *Mask++; 904 if (InvertMask) M = ~M; 905 if (AddBits) Bits[i] |= BitWord(M) << b; 906 else Bits[i] &= ~(BitWord(M) << b); 907 } 908 if (AddBits) 909 clear_unused_bits(); 910 } 911 912 public: 913 /// Return the size (in bytes) of the bit vector. 914 size_t getMemorySize() const { return Bits.size() * sizeof(BitWord); } 915 size_t getBitCapacity() const { return Bits.size() * BITWORD_SIZE; } 916 }; 917 918 inline size_t capacity_in_bytes(const BitVector &X) { 919 return X.getMemorySize(); 920 } 921 922 template <> struct DenseMapInfo<BitVector> { 923 static inline BitVector getEmptyKey() { return BitVector(); } 924 static inline BitVector getTombstoneKey() { 925 BitVector V; 926 V.invalid(); 927 return V; 928 } 929 static unsigned getHashValue(const BitVector &V) { 930 return DenseMapInfo<std::pair<unsigned, ArrayRef<uintptr_t>>>::getHashValue( 931 std::make_pair(V.size(), V.getData())); 932 } 933 static bool isEqual(const BitVector &LHS, const BitVector &RHS) { 934 if (LHS.isInvalid() || RHS.isInvalid()) 935 return LHS.isInvalid() == RHS.isInvalid(); 936 return LHS == RHS; 937 } 938 }; 939 } // end namespace llvm 940 941 namespace std { 942 /// Implement std::swap in terms of BitVector swap. 943 inline void 944 swap(llvm::BitVector &LHS, llvm::BitVector &RHS) { 945 LHS.swap(RHS); 946 } 947 } // end namespace std 948 949 #endif // LLVM_ADT_BITVECTOR_H 950