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