1 //===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the BitVector class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ADT_BITVECTOR_H
15 #define LLVM_ADT_BITVECTOR_H
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/iterator_range.h"
19 #include "llvm/Support/MathExtras.h"
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;
37 assert(Current != -1 && "Trying to advance past end.");
38 Current = Parent.find_next(Current);
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;
48 const_set_bits_iterator_impl operator++(int) {
54 const_set_bits_iterator_impl &operator++() {
59 unsigned operator*() const { return Current; }
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;
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;
75 typedef unsigned long BitWord;
77 enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT };
79 static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32,
80 "Unsupported word size");
82 MutableArrayRef<BitWord> Bits; // Actual bits.
83 unsigned Size; // Size of bitvector in bits.
86 typedef unsigned size_type;
87 // Encapsulation of a single bit.
89 friend class BitVector;
95 reference(BitVector &b, unsigned Idx) {
96 WordRef = &b.Bits[Idx / BITWORD_SIZE];
97 BitPos = Idx % BITWORD_SIZE;
100 reference() = delete;
101 reference(const reference&) = default;
103 reference &operator=(reference t) {
108 reference& operator=(bool t) {
110 *WordRef |= BitWord(1) << BitPos;
112 *WordRef &= ~(BitWord(1) << BitPos);
116 operator bool() const {
117 return ((*WordRef) & (BitWord(1) << BitPos)) != 0;
121 typedef const_set_bits_iterator_impl<BitVector> const_set_bits_iterator;
122 typedef const_set_bits_iterator set_iterator;
124 const_set_bits_iterator set_bits_begin() const {
125 return const_set_bits_iterator(*this);
127 const_set_bits_iterator set_bits_end() const {
128 return const_set_bits_iterator(*this, -1);
130 iterator_range<const_set_bits_iterator> set_bits() const {
131 return make_range(set_bits_begin(), set_bits_end());
134 /// BitVector default ctor - Creates an empty bitvector.
135 BitVector() : Size(0) {}
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);
147 /// BitVector copy ctor.
148 BitVector(const BitVector &RHS) : Size(RHS.size()) {
150 Bits = MutableArrayRef<BitWord>();
154 size_t Capacity = NumBitWords(RHS.size());
155 Bits = allocate(Capacity);
156 std::memcpy(Bits.data(), RHS.Bits.data(), Capacity * sizeof(BitWord));
159 BitVector(BitVector &&RHS) : Bits(RHS.Bits), Size(RHS.Size) {
160 RHS.Bits = MutableArrayRef<BitWord>();
164 ~BitVector() { std::free(Bits.data()); }
166 /// empty - Tests whether there are no bits in this bitvector.
167 bool empty() const { return Size == 0; }
169 /// size - Returns the number of bits in this bitvector.
170 size_type size() const { return Size; }
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]);
180 /// any - Returns true if any bit is set.
182 for (unsigned i = 0; i < NumBitWords(size()); ++i)
188 /// all - Returns true if all bits are set.
190 for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i)
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] == (1UL << Remainder) - 1;
201 /// none - Returns true if none of the bits are set.
206 /// find_first_in - Returns the index of the first set bit in the range
207 /// [Begin, End). Returns -1 if all bits in the range are unset.
208 int find_first_in(unsigned Begin, unsigned End) const {
209 assert(Begin <= End && End <= Size);
213 unsigned FirstWord = Begin / BITWORD_SIZE;
214 unsigned LastWord = (End - 1) / BITWORD_SIZE;
216 // Check subsequent words.
217 for (unsigned i = FirstWord; i <= LastWord; ++i) {
218 BitWord Copy = Bits[i];
220 if (i == FirstWord) {
221 unsigned FirstBit = Begin % BITWORD_SIZE;
222 Copy &= maskTrailingZeros<BitWord>(FirstBit);
226 unsigned LastBit = (End - 1) % BITWORD_SIZE;
227 Copy &= maskTrailingOnes<BitWord>(LastBit + 1);
230 return i * BITWORD_SIZE + countTrailingZeros(Copy);
235 /// find_last_in - Returns the index of the last set bit in the range
236 /// [Begin, End). Returns -1 if all bits in the range are unset.
237 int find_last_in(unsigned Begin, unsigned End) const {
238 assert(Begin <= End && End <= Size);
242 unsigned LastWord = (End - 1) / BITWORD_SIZE;
243 unsigned FirstWord = Begin / BITWORD_SIZE;
245 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
246 unsigned CurrentWord = i - 1;
248 BitWord Copy = Bits[CurrentWord];
249 if (CurrentWord == LastWord) {
250 unsigned LastBit = (End - 1) % BITWORD_SIZE;
251 Copy &= maskTrailingOnes<BitWord>(LastBit + 1);
254 if (CurrentWord == FirstWord) {
255 unsigned FirstBit = Begin % BITWORD_SIZE;
256 Copy &= maskTrailingZeros<BitWord>(FirstBit);
260 return (CurrentWord + 1) * BITWORD_SIZE - countLeadingZeros(Copy) - 1;
266 /// find_first_unset_in - Returns the index of the first unset bit in the
267 /// range [Begin, End). Returns -1 if all bits in the range are set.
268 int find_first_unset_in(unsigned Begin, unsigned End) const {
269 assert(Begin <= End && End <= Size);
273 unsigned FirstWord = Begin / BITWORD_SIZE;
274 unsigned LastWord = (End - 1) / BITWORD_SIZE;
276 // Check subsequent words.
277 for (unsigned i = FirstWord; i <= LastWord; ++i) {
278 BitWord Copy = Bits[i];
280 if (i == FirstWord) {
281 unsigned FirstBit = Begin % BITWORD_SIZE;
282 Copy |= maskTrailingOnes<BitWord>(FirstBit);
286 unsigned LastBit = (End - 1) % BITWORD_SIZE;
287 Copy |= maskTrailingZeros<BitWord>(LastBit + 1);
290 unsigned Result = i * BITWORD_SIZE + countTrailingOnes(Copy);
291 return Result < size() ? Result : -1;
297 /// find_last_unset_in - Returns the index of the last unset bit in the
298 /// range [Begin, End). Returns -1 if all bits in the range are set.
299 int find_last_unset_in(unsigned Begin, unsigned End) const {
300 assert(Begin <= End && End <= Size);
304 unsigned LastWord = (End - 1) / BITWORD_SIZE;
305 unsigned FirstWord = Begin / BITWORD_SIZE;
307 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
308 unsigned CurrentWord = i - 1;
310 BitWord Copy = Bits[CurrentWord];
311 if (CurrentWord == LastWord) {
312 unsigned LastBit = (End - 1) % BITWORD_SIZE;
313 Copy |= maskTrailingZeros<BitWord>(LastBit + 1);
316 if (CurrentWord == FirstWord) {
317 unsigned FirstBit = Begin % BITWORD_SIZE;
318 Copy |= maskTrailingOnes<BitWord>(FirstBit);
323 (CurrentWord + 1) * BITWORD_SIZE - countLeadingOnes(Copy) - 1;
324 return Result < Size ? Result : -1;
330 /// find_first - Returns the index of the first set bit, -1 if none
331 /// of the bits are set.
332 int find_first() const { return find_first_in(0, Size); }
334 /// find_last - Returns the index of the last set bit, -1 if none of the bits
336 int find_last() const { return find_last_in(0, Size); }
338 /// find_next - Returns the index of the next set bit following the
339 /// "Prev" bit. Returns -1 if the next set bit is not found.
340 int find_next(unsigned Prev) const { return find_first_in(Prev + 1, Size); }
342 /// find_prev - Returns the index of the first set bit that precedes the
343 /// the bit at \p PriorTo. Returns -1 if all previous bits are unset.
344 int find_prev(unsigned PriorTo) const { return find_last_in(0, PriorTo); }
346 /// find_first_unset - Returns the index of the first unset bit, -1 if all
347 /// of the bits are set.
348 int find_first_unset() const { return find_first_unset_in(0, Size); }
350 /// find_next_unset - Returns the index of the next unset bit following the
351 /// "Prev" bit. Returns -1 if all remaining bits are set.
352 int find_next_unset(unsigned Prev) const {
353 return find_first_unset_in(Prev + 1, Size);
356 /// find_last_unset - Returns the index of the last unset bit, -1 if all of
357 /// the bits are set.
358 int find_last_unset() const { return find_last_unset_in(0, Size); }
360 /// find_prev_unset - Returns the index of the first unset bit that precedes
361 /// the bit at \p PriorTo. Returns -1 if all previous bits are set.
362 int find_prev_unset(unsigned PriorTo) {
363 return find_last_unset_in(0, PriorTo);
366 /// clear - Removes all bits from the bitvector. Does not change capacity.
371 /// resize - Grow or shrink the bitvector.
372 void resize(unsigned N, bool t = false) {
373 if (N > getBitCapacity()) {
374 unsigned OldCapacity = Bits.size();
376 init_words(Bits.drop_front(OldCapacity), t);
379 // Set any old unused bits that are now included in the BitVector. This
380 // may set bits that are not included in the new vector, but we will clear
381 // them back out below.
385 // Update the size, and clear out any bits that are now unused
386 unsigned OldSize = Size;
388 if (t || N < OldSize)
392 void reserve(unsigned N) {
393 if (N > getBitCapacity())
399 init_words(Bits, true);
404 BitVector &set(unsigned Idx) {
405 assert(Bits.data() && "Bits never allocated");
406 Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE);
410 /// set - Efficiently set a range of bits in [I, E)
411 BitVector &set(unsigned I, unsigned E) {
412 assert(I <= E && "Attempted to set backwards range!");
413 assert(E <= size() && "Attempted to set out-of-bounds range!");
415 if (I == E) return *this;
417 if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
418 BitWord EMask = 1UL << (E % BITWORD_SIZE);
419 BitWord IMask = 1UL << (I % BITWORD_SIZE);
420 BitWord Mask = EMask - IMask;
421 Bits[I / BITWORD_SIZE] |= Mask;
425 BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE);
426 Bits[I / BITWORD_SIZE] |= PrefixMask;
427 I = alignTo(I, BITWORD_SIZE);
429 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
430 Bits[I / BITWORD_SIZE] = ~0UL;
432 BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1;
434 Bits[I / BITWORD_SIZE] |= PostfixMask;
440 init_words(Bits, false);
444 BitVector &reset(unsigned Idx) {
445 Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE));
449 /// reset - Efficiently reset a range of bits in [I, E)
450 BitVector &reset(unsigned I, unsigned E) {
451 assert(I <= E && "Attempted to reset backwards range!");
452 assert(E <= size() && "Attempted to reset out-of-bounds range!");
454 if (I == E) return *this;
456 if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
457 BitWord EMask = 1UL << (E % BITWORD_SIZE);
458 BitWord IMask = 1UL << (I % BITWORD_SIZE);
459 BitWord Mask = EMask - IMask;
460 Bits[I / BITWORD_SIZE] &= ~Mask;
464 BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE);
465 Bits[I / BITWORD_SIZE] &= ~PrefixMask;
466 I = alignTo(I, BITWORD_SIZE);
468 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
469 Bits[I / BITWORD_SIZE] = 0UL;
471 BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1;
473 Bits[I / BITWORD_SIZE] &= ~PostfixMask;
479 for (unsigned i = 0; i < NumBitWords(size()); ++i)
485 BitVector &flip(unsigned Idx) {
486 Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE);
491 reference operator[](unsigned Idx) {
492 assert (Idx < Size && "Out-of-bounds Bit access.");
493 return reference(*this, Idx);
496 bool operator[](unsigned Idx) const {
497 assert (Idx < Size && "Out-of-bounds Bit access.");
498 BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE);
499 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0;
502 bool test(unsigned Idx) const {
506 /// Test if any common bits are set.
507 bool anyCommon(const BitVector &RHS) const {
508 unsigned ThisWords = NumBitWords(size());
509 unsigned RHSWords = NumBitWords(RHS.size());
510 for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i)
511 if (Bits[i] & RHS.Bits[i])
516 // Comparison operators.
517 bool operator==(const BitVector &RHS) const {
518 unsigned ThisWords = NumBitWords(size());
519 unsigned RHSWords = NumBitWords(RHS.size());
521 for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
522 if (Bits[i] != RHS.Bits[i])
525 // Verify that any extra words are all zeros.
526 if (i != ThisWords) {
527 for (; i != ThisWords; ++i)
530 } else if (i != RHSWords) {
531 for (; i != RHSWords; ++i)
538 bool operator!=(const BitVector &RHS) const {
539 return !(*this == RHS);
542 /// Intersection, union, disjoint union.
543 BitVector &operator&=(const BitVector &RHS) {
544 unsigned ThisWords = NumBitWords(size());
545 unsigned RHSWords = NumBitWords(RHS.size());
547 for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
548 Bits[i] &= RHS.Bits[i];
550 // Any bits that are just in this bitvector become zero, because they aren't
551 // in the RHS bit vector. Any words only in RHS are ignored because they
552 // are already zero in the LHS.
553 for (; i != ThisWords; ++i)
559 /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
560 BitVector &reset(const BitVector &RHS) {
561 unsigned ThisWords = NumBitWords(size());
562 unsigned RHSWords = NumBitWords(RHS.size());
564 for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
565 Bits[i] &= ~RHS.Bits[i];
569 /// test - Check if (This - RHS) is zero.
570 /// This is the same as reset(RHS) and any().
571 bool test(const BitVector &RHS) const {
572 unsigned ThisWords = NumBitWords(size());
573 unsigned RHSWords = NumBitWords(RHS.size());
575 for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
576 if ((Bits[i] & ~RHS.Bits[i]) != 0)
579 for (; i != ThisWords ; ++i)
586 BitVector &operator|=(const BitVector &RHS) {
587 if (size() < RHS.size())
589 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
590 Bits[i] |= RHS.Bits[i];
594 BitVector &operator^=(const BitVector &RHS) {
595 if (size() < RHS.size())
597 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
598 Bits[i] ^= RHS.Bits[i];
602 BitVector &operator>>=(unsigned N) {
604 if (LLVM_UNLIKELY(empty() || N == 0))
607 unsigned NumWords = NumBitWords(Size);
608 assert(NumWords >= 1);
610 wordShr(N / BITWORD_SIZE);
612 unsigned BitDistance = N % BITWORD_SIZE;
613 if (BitDistance == 0)
616 // When the shift size is not a multiple of the word size, then we have
617 // a tricky situation where each word in succession needs to extract some
618 // of the bits from the next word and or them into this word while
619 // shifting this word to make room for the new bits. This has to be done
620 // for every word in the array.
622 // Since we're shifting each word right, some bits will fall off the end
623 // of each word to the right, and empty space will be created on the left.
624 // The final word in the array will lose bits permanently, so starting at
625 // the beginning, work forwards shifting each word to the right, and
626 // OR'ing in the bits from the end of the next word to the beginning of
630 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting right
632 // Step 1: Word[0] >>= 4 ; 0x0ABBCCDD
633 // Step 2: Word[0] |= 0x10000000 ; 0x1ABBCCDD
634 // Step 3: Word[1] >>= 4 ; 0x0EEFF001
635 // Step 4: Word[1] |= 0x50000000 ; 0x5EEFF001
636 // Step 5: Word[2] >>= 4 ; 0x02334455
637 // Result: { 0x1ABBCCDD, 0x5EEFF001, 0x02334455 }
638 const BitWord Mask = maskTrailingOnes<BitWord>(BitDistance);
639 const unsigned LSH = BITWORD_SIZE - BitDistance;
641 for (unsigned I = 0; I < NumWords - 1; ++I) {
642 Bits[I] >>= BitDistance;
643 Bits[I] |= (Bits[I + 1] & Mask) << LSH;
646 Bits[NumWords - 1] >>= BitDistance;
651 BitVector &operator<<=(unsigned N) {
653 if (LLVM_UNLIKELY(empty() || N == 0))
656 unsigned NumWords = NumBitWords(Size);
657 assert(NumWords >= 1);
659 wordShl(N / BITWORD_SIZE);
661 unsigned BitDistance = N % BITWORD_SIZE;
662 if (BitDistance == 0)
665 // When the shift size is not a multiple of the word size, then we have
666 // a tricky situation where each word in succession needs to extract some
667 // of the bits from the previous word and or them into this word while
668 // shifting this word to make room for the new bits. This has to be done
669 // for every word in the array. This is similar to the algorithm outlined
670 // in operator>>=, but backwards.
672 // Since we're shifting each word left, some bits will fall off the end
673 // of each word to the left, and empty space will be created on the right.
674 // The first word in the array will lose bits permanently, so starting at
675 // the end, work backwards shifting each word to the left, and OR'ing
676 // in the bits from the end of the next word to the beginning of the
680 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting left
682 // Step 1: Word[2] <<= 4 ; 0x23344550
683 // Step 2: Word[2] |= 0x0000000E ; 0x2334455E
684 // Step 3: Word[1] <<= 4 ; 0xEFF00110
685 // Step 4: Word[1] |= 0x0000000A ; 0xEFF0011A
686 // Step 5: Word[0] <<= 4 ; 0xABBCCDD0
687 // Result: { 0xABBCCDD0, 0xEFF0011A, 0x2334455E }
688 const BitWord Mask = maskLeadingOnes<BitWord>(BitDistance);
689 const unsigned RSH = BITWORD_SIZE - BitDistance;
691 for (int I = NumWords - 1; I > 0; --I) {
692 Bits[I] <<= BitDistance;
693 Bits[I] |= (Bits[I - 1] & Mask) >> RSH;
695 Bits[0] <<= BitDistance;
701 // Assignment operator.
702 const BitVector &operator=(const BitVector &RHS) {
703 if (this == &RHS) return *this;
706 unsigned RHSWords = NumBitWords(Size);
707 if (Size <= getBitCapacity()) {
709 std::memcpy(Bits.data(), RHS.Bits.data(), RHSWords * sizeof(BitWord));
714 // Grow the bitvector to have enough elements.
715 unsigned NewCapacity = RHSWords;
716 assert(NewCapacity > 0 && "negative capacity?");
717 auto NewBits = allocate(NewCapacity);
718 std::memcpy(NewBits.data(), RHS.Bits.data(), NewCapacity * sizeof(BitWord));
720 // Destroy the old bits.
721 std::free(Bits.data());
727 const BitVector &operator=(BitVector &&RHS) {
728 if (this == &RHS) return *this;
730 std::free(Bits.data());
734 RHS.Bits = MutableArrayRef<BitWord>();
740 void swap(BitVector &RHS) {
741 std::swap(Bits, RHS.Bits);
742 std::swap(Size, RHS.Size);
745 //===--------------------------------------------------------------------===//
746 // Portable bit mask operations.
747 //===--------------------------------------------------------------------===//
749 // These methods all operate on arrays of uint32_t, each holding 32 bits. The
750 // fixed word size makes it easier to work with literal bit vector constants
753 // The LSB in each word is the lowest numbered bit. The size of a portable
754 // bit mask is always a whole multiple of 32 bits. If no bit mask size is
755 // given, the bit mask is assumed to cover the entire BitVector.
757 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize.
758 /// This computes "*this |= Mask".
759 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
760 applyMask<true, false>(Mask, MaskWords);
763 /// clearBitsInMask - Clear any bits in this vector that are set in Mask.
764 /// Don't resize. This computes "*this &= ~Mask".
765 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
766 applyMask<false, false>(Mask, MaskWords);
769 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask.
770 /// Don't resize. This computes "*this |= ~Mask".
771 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
772 applyMask<true, true>(Mask, MaskWords);
775 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask.
776 /// Don't resize. This computes "*this &= Mask".
777 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
778 applyMask<false, true>(Mask, MaskWords);
782 /// Perform a logical left shift of \p Count words by moving everything
783 /// \p Count words to the right in memory.
785 /// While confusing, words are stored from least significant at Bits[0] to
786 /// most significant at Bits[NumWords-1]. A logical shift left, however,
787 /// moves the current least significant bit to a higher logical index, and
788 /// fills the previous least significant bits with 0. Thus, we actually
789 /// need to move the bytes of the memory to the right, not to the left.
791 /// Words = [0xBBBBAAAA, 0xDDDDFFFF, 0x00000000, 0xDDDD0000]
792 /// represents a BitVector where 0xBBBBAAAA contain the least significant
793 /// bits. So if we want to shift the BitVector left by 2 words, we need to
794 /// turn this into 0x00000000 0x00000000 0xBBBBAAAA 0xDDDDFFFF by using a
795 /// memmove which moves right, not left.
796 void wordShl(uint32_t Count) {
800 uint32_t NumWords = NumBitWords(Size);
802 auto Src = Bits.take_front(NumWords).drop_back(Count);
803 auto Dest = Bits.take_front(NumWords).drop_front(Count);
805 // Since we always move Word-sized chunks of data with src and dest both
806 // aligned to a word-boundary, we don't need to worry about endianness
808 std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
809 std::memset(Bits.data(), 0, Count * sizeof(BitWord));
813 /// Perform a logical right shift of \p Count words by moving those
814 /// words to the left in memory. See wordShl for more information.
816 void wordShr(uint32_t Count) {
820 uint32_t NumWords = NumBitWords(Size);
822 auto Src = Bits.take_front(NumWords).drop_front(Count);
823 auto Dest = Bits.take_front(NumWords).drop_back(Count);
824 assert(Dest.size() == Src.size());
826 std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
827 std::memset(Dest.end(), 0, Count * sizeof(BitWord));
830 MutableArrayRef<BitWord> allocate(size_t NumWords) {
831 BitWord *RawBits = static_cast<BitWord *>(
832 safe_malloc(NumWords * sizeof(BitWord)));
833 return MutableArrayRef<BitWord>(RawBits, NumWords);
836 int next_unset_in_word(int WordIndex, BitWord Word) const {
837 unsigned Result = WordIndex * BITWORD_SIZE + countTrailingOnes(Word);
838 return Result < size() ? Result : -1;
841 unsigned NumBitWords(unsigned S) const {
842 return (S + BITWORD_SIZE-1) / BITWORD_SIZE;
845 // Set the unused bits in the high words.
846 void set_unused_bits(bool t = true) {
847 // Set high words first.
848 unsigned UsedWords = NumBitWords(Size);
849 if (Bits.size() > UsedWords)
850 init_words(Bits.drop_front(UsedWords), t);
852 // Then set any stray high bits of the last used word.
853 unsigned ExtraBits = Size % BITWORD_SIZE;
855 BitWord ExtraBitMask = ~0UL << ExtraBits;
857 Bits[UsedWords-1] |= ExtraBitMask;
859 Bits[UsedWords-1] &= ~ExtraBitMask;
863 // Clear the unused bits in the high words.
864 void clear_unused_bits() {
865 set_unused_bits(false);
868 void grow(unsigned NewSize) {
869 size_t NewCapacity = std::max<size_t>(NumBitWords(NewSize), Bits.size() * 2);
870 assert(NewCapacity > 0 && "realloc-ing zero space");
871 BitWord *NewBits = static_cast<BitWord *>(
872 safe_realloc(Bits.data(), NewCapacity * sizeof(BitWord)));
873 Bits = MutableArrayRef<BitWord>(NewBits, NewCapacity);
877 void init_words(MutableArrayRef<BitWord> B, bool t) {
879 memset(B.data(), 0 - (int)t, B.size() * sizeof(BitWord));
882 template<bool AddBits, bool InvertMask>
883 void applyMask(const uint32_t *Mask, unsigned MaskWords) {
884 static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size.");
885 MaskWords = std::min(MaskWords, (size() + 31) / 32);
886 const unsigned Scale = BITWORD_SIZE / 32;
888 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) {
889 BitWord BW = Bits[i];
890 // This inner loop should unroll completely when BITWORD_SIZE > 32.
891 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) {
892 uint32_t M = *Mask++;
893 if (InvertMask) M = ~M;
894 if (AddBits) BW |= BitWord(M) << b;
895 else BW &= ~(BitWord(M) << b);
899 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) {
900 uint32_t M = *Mask++;
901 if (InvertMask) M = ~M;
902 if (AddBits) Bits[i] |= BitWord(M) << b;
903 else Bits[i] &= ~(BitWord(M) << b);
910 /// Return the size (in bytes) of the bit vector.
911 size_t getMemorySize() const { return Bits.size() * sizeof(BitWord); }
912 size_t getBitCapacity() const { return Bits.size() * BITWORD_SIZE; }
915 inline size_t capacity_in_bytes(const BitVector &X) {
916 return X.getMemorySize();
919 } // end namespace llvm
922 /// Implement std::swap in terms of BitVector swap.
924 swap(llvm::BitVector &LHS, llvm::BitVector &RHS) {
927 } // end namespace std
929 #endif // LLVM_ADT_BITVECTOR_H