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+//===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the BitVector class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_BITVECTOR_H
+#define LLVM_ADT_BITVECTOR_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Support/MathExtras.h"
+#include <algorithm>
+#include <cassert>
+#include <climits>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <utility>
+
+namespace llvm {
+
+/// ForwardIterator for the bits that are set.
+/// Iterators get invalidated when resize / reserve is called.
+template <typename BitVectorT> class const_set_bits_iterator_impl {
+ const BitVectorT &Parent;
+ int Current = 0;
+
+ void advance() {
+ assert(Current != -1 && "Trying to advance past end.");
+ Current = Parent.find_next(Current);
+ }
+
+public:
+ const_set_bits_iterator_impl(const BitVectorT &Parent, int Current)
+ : Parent(Parent), Current(Current) {}
+ explicit const_set_bits_iterator_impl(const BitVectorT &Parent)
+ : const_set_bits_iterator_impl(Parent, Parent.find_first()) {}
+ const_set_bits_iterator_impl(const const_set_bits_iterator_impl &) = default;
+
+ const_set_bits_iterator_impl operator++(int) {
+ auto Prev = *this;
+ advance();
+ return Prev;
+ }
+
+ const_set_bits_iterator_impl &operator++() {
+ advance();
+ return *this;
+ }
+
+ unsigned operator*() const { return Current; }
+
+ bool operator==(const const_set_bits_iterator_impl &Other) const {
+ assert(&Parent == &Other.Parent &&
+ "Comparing iterators from different BitVectors");
+ return Current == Other.Current;
+ }
+
+ bool operator!=(const const_set_bits_iterator_impl &Other) const {
+ assert(&Parent == &Other.Parent &&
+ "Comparing iterators from different BitVectors");
+ return Current != Other.Current;
+ }
+};
+
+class BitVector {
+ typedef unsigned long BitWord;
+
+ enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT };
+
+ static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32,
+ "Unsupported word size");
+
+ MutableArrayRef<BitWord> Bits; // Actual bits.
+ unsigned Size; // Size of bitvector in bits.
+
+public:
+ typedef unsigned size_type;
+ // Encapsulation of a single bit.
+ class reference {
+ friend class BitVector;
+
+ BitWord *WordRef;
+ unsigned BitPos;
+
+ public:
+ reference(BitVector &b, unsigned Idx) {
+ WordRef = &b.Bits[Idx / BITWORD_SIZE];
+ BitPos = Idx % BITWORD_SIZE;
+ }
+
+ reference() = delete;
+ reference(const reference&) = default;
+
+ reference &operator=(reference t) {
+ *this = bool(t);
+ return *this;
+ }
+
+ reference& operator=(bool t) {
+ if (t)
+ *WordRef |= BitWord(1) << BitPos;
+ else
+ *WordRef &= ~(BitWord(1) << BitPos);
+ return *this;
+ }
+
+ operator bool() const {
+ return ((*WordRef) & (BitWord(1) << BitPos)) != 0;
+ }
+ };
+
+ typedef const_set_bits_iterator_impl<BitVector> const_set_bits_iterator;
+ typedef const_set_bits_iterator set_iterator;
+
+ const_set_bits_iterator set_bits_begin() const {
+ return const_set_bits_iterator(*this);
+ }
+ const_set_bits_iterator set_bits_end() const {
+ return const_set_bits_iterator(*this, -1);
+ }
+ iterator_range<const_set_bits_iterator> set_bits() const {
+ return make_range(set_bits_begin(), set_bits_end());
+ }
+
+ /// BitVector default ctor - Creates an empty bitvector.
+ BitVector() : Size(0) {}
+
+ /// BitVector ctor - Creates a bitvector of specified number of bits. All
+ /// bits are initialized to the specified value.
+ explicit BitVector(unsigned s, bool t = false) : Size(s) {
+ size_t Capacity = NumBitWords(s);
+ Bits = allocate(Capacity);
+ init_words(Bits, t);
+ if (t)
+ clear_unused_bits();
+ }
+
+ /// BitVector copy ctor.
+ BitVector(const BitVector &RHS) : Size(RHS.size()) {
+ if (Size == 0) {
+ Bits = MutableArrayRef<BitWord>();
+ return;
+ }
+
+ size_t Capacity = NumBitWords(RHS.size());
+ Bits = allocate(Capacity);
+ std::memcpy(Bits.data(), RHS.Bits.data(), Capacity * sizeof(BitWord));
+ }
+
+ BitVector(BitVector &&RHS) : Bits(RHS.Bits), Size(RHS.Size) {
+ RHS.Bits = MutableArrayRef<BitWord>();
+ RHS.Size = 0;
+ }
+
+ ~BitVector() { std::free(Bits.data()); }
+
+ /// empty - Tests whether there are no bits in this bitvector.
+ bool empty() const { return Size == 0; }
+
+ /// size - Returns the number of bits in this bitvector.
+ size_type size() const { return Size; }
+
+ /// count - Returns the number of bits which are set.
+ size_type count() const {
+ unsigned NumBits = 0;
+ for (unsigned i = 0; i < NumBitWords(size()); ++i)
+ NumBits += countPopulation(Bits[i]);
+ return NumBits;
+ }
+
+ /// any - Returns true if any bit is set.
+ bool any() const {
+ for (unsigned i = 0; i < NumBitWords(size()); ++i)
+ if (Bits[i] != 0)
+ return true;
+ return false;
+ }
+
+ /// all - Returns true if all bits are set.
+ bool all() const {
+ for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i)
+ if (Bits[i] != ~0UL)
+ return false;
+
+ // If bits remain check that they are ones. The unused bits are always zero.
+ if (unsigned Remainder = Size % BITWORD_SIZE)
+ return Bits[Size / BITWORD_SIZE] == (1UL << Remainder) - 1;
+
+ return true;
+ }
+
+ /// none - Returns true if none of the bits are set.
+ bool none() const {
+ return !any();
+ }
+
+ /// find_first_in - Returns the index of the first set bit in the range
+ /// [Begin, End). Returns -1 if all bits in the range are unset.
+ int find_first_in(unsigned Begin, unsigned End) const {
+ assert(Begin <= End && End <= Size);
+ if (Begin == End)
+ return -1;
+
+ unsigned FirstWord = Begin / BITWORD_SIZE;
+ unsigned LastWord = (End - 1) / BITWORD_SIZE;
+
+ // Check subsequent words.
+ for (unsigned i = FirstWord; i <= LastWord; ++i) {
+ BitWord Copy = Bits[i];
+
+ if (i == FirstWord) {
+ unsigned FirstBit = Begin % BITWORD_SIZE;
+ Copy &= maskTrailingZeros<BitWord>(FirstBit);
+ }
+
+ if (i == LastWord) {
+ unsigned LastBit = (End - 1) % BITWORD_SIZE;
+ Copy &= maskTrailingOnes<BitWord>(LastBit + 1);
+ }
+ if (Copy != 0)
+ return i * BITWORD_SIZE + countTrailingZeros(Copy);
+ }
+ return -1;
+ }
+
+ /// find_last_in - Returns the index of the last set bit in the range
+ /// [Begin, End). Returns -1 if all bits in the range are unset.
+ int find_last_in(unsigned Begin, unsigned End) const {
+ assert(Begin <= End && End <= Size);
+ if (Begin == End)
+ return -1;
+
+ unsigned LastWord = (End - 1) / BITWORD_SIZE;
+ unsigned FirstWord = Begin / BITWORD_SIZE;
+
+ for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
+ unsigned CurrentWord = i - 1;
+
+ BitWord Copy = Bits[CurrentWord];
+ if (CurrentWord == LastWord) {
+ unsigned LastBit = (End - 1) % BITWORD_SIZE;
+ Copy &= maskTrailingOnes<BitWord>(LastBit + 1);
+ }
+
+ if (CurrentWord == FirstWord) {
+ unsigned FirstBit = Begin % BITWORD_SIZE;
+ Copy &= maskTrailingZeros<BitWord>(FirstBit);
+ }
+
+ if (Copy != 0)
+ return (CurrentWord + 1) * BITWORD_SIZE - countLeadingZeros(Copy) - 1;
+ }
+
+ return -1;
+ }
+
+ /// find_first_unset_in - Returns the index of the first unset bit in the
+ /// range [Begin, End). Returns -1 if all bits in the range are set.
+ int find_first_unset_in(unsigned Begin, unsigned End) const {
+ assert(Begin <= End && End <= Size);
+ if (Begin == End)
+ return -1;
+
+ unsigned FirstWord = Begin / BITWORD_SIZE;
+ unsigned LastWord = (End - 1) / BITWORD_SIZE;
+
+ // Check subsequent words.
+ for (unsigned i = FirstWord; i <= LastWord; ++i) {
+ BitWord Copy = Bits[i];
+
+ if (i == FirstWord) {
+ unsigned FirstBit = Begin % BITWORD_SIZE;
+ Copy |= maskTrailingOnes<BitWord>(FirstBit);
+ }
+
+ if (i == LastWord) {
+ unsigned LastBit = (End - 1) % BITWORD_SIZE;
+ Copy |= maskTrailingZeros<BitWord>(LastBit + 1);
+ }
+ if (Copy != ~0UL) {
+ unsigned Result = i * BITWORD_SIZE + countTrailingOnes(Copy);
+ return Result < size() ? Result : -1;
+ }
+ }
+ return -1;
+ }
+
+ /// find_last_unset_in - Returns the index of the last unset bit in the
+ /// range [Begin, End). Returns -1 if all bits in the range are set.
+ int find_last_unset_in(unsigned Begin, unsigned End) const {
+ assert(Begin <= End && End <= Size);
+ if (Begin == End)
+ return -1;
+
+ unsigned LastWord = (End - 1) / BITWORD_SIZE;
+ unsigned FirstWord = Begin / BITWORD_SIZE;
+
+ for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
+ unsigned CurrentWord = i - 1;
+
+ BitWord Copy = Bits[CurrentWord];
+ if (CurrentWord == LastWord) {
+ unsigned LastBit = (End - 1) % BITWORD_SIZE;
+ Copy |= maskTrailingZeros<BitWord>(LastBit + 1);
+ }
+
+ if (CurrentWord == FirstWord) {
+ unsigned FirstBit = Begin % BITWORD_SIZE;
+ Copy |= maskTrailingOnes<BitWord>(FirstBit);
+ }
+
+ if (Copy != ~0UL) {
+ unsigned Result =
+ (CurrentWord + 1) * BITWORD_SIZE - countLeadingOnes(Copy) - 1;
+ return Result < Size ? Result : -1;
+ }
+ }
+ return -1;
+ }
+
+ /// find_first - Returns the index of the first set bit, -1 if none
+ /// of the bits are set.
+ int find_first() const { return find_first_in(0, Size); }
+
+ /// find_last - Returns the index of the last set bit, -1 if none of the bits
+ /// are set.
+ int find_last() const { return find_last_in(0, Size); }
+
+ /// find_next - Returns the index of the next set bit following the
+ /// "Prev" bit. Returns -1 if the next set bit is not found.
+ int find_next(unsigned Prev) const { return find_first_in(Prev + 1, Size); }
+
+ /// find_prev - Returns the index of the first set bit that precedes the
+ /// the bit at \p PriorTo. Returns -1 if all previous bits are unset.
+ int find_prev(unsigned PriorTo) const { return find_last_in(0, PriorTo); }
+
+ /// find_first_unset - Returns the index of the first unset bit, -1 if all
+ /// of the bits are set.
+ int find_first_unset() const { return find_first_unset_in(0, Size); }
+
+ /// find_next_unset - Returns the index of the next unset bit following the
+ /// "Prev" bit. Returns -1 if all remaining bits are set.
+ int find_next_unset(unsigned Prev) const {
+ return find_first_unset_in(Prev + 1, Size);
+ }
+
+ /// find_last_unset - Returns the index of the last unset bit, -1 if all of
+ /// the bits are set.
+ int find_last_unset() const { return find_last_unset_in(0, Size); }
+
+ /// find_prev_unset - Returns the index of the first unset bit that precedes
+ /// the bit at \p PriorTo. Returns -1 if all previous bits are set.
+ int find_prev_unset(unsigned PriorTo) {
+ return find_last_unset_in(0, PriorTo);
+ }
+
+ /// clear - Removes all bits from the bitvector. Does not change capacity.
+ void clear() {
+ Size = 0;
+ }
+
+ /// resize - Grow or shrink the bitvector.
+ void resize(unsigned N, bool t = false) {
+ if (N > getBitCapacity()) {
+ unsigned OldCapacity = Bits.size();
+ grow(N);
+ init_words(Bits.drop_front(OldCapacity), t);
+ }
+
+ // Set any old unused bits that are now included in the BitVector. This
+ // may set bits that are not included in the new vector, but we will clear
+ // them back out below.
+ if (N > Size)
+ set_unused_bits(t);
+
+ // Update the size, and clear out any bits that are now unused
+ unsigned OldSize = Size;
+ Size = N;
+ if (t || N < OldSize)
+ clear_unused_bits();
+ }
+
+ void reserve(unsigned N) {
+ if (N > getBitCapacity())
+ grow(N);
+ }
+
+ // Set, reset, flip
+ BitVector &set() {
+ init_words(Bits, true);
+ clear_unused_bits();
+ return *this;
+ }
+
+ BitVector &set(unsigned Idx) {
+ assert(Bits.data() && "Bits never allocated");
+ Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE);
+ return *this;
+ }
+
+ /// set - Efficiently set a range of bits in [I, E)
+ BitVector &set(unsigned I, unsigned E) {
+ assert(I <= E && "Attempted to set backwards range!");
+ assert(E <= size() && "Attempted to set out-of-bounds range!");
+
+ if (I == E) return *this;
+
+ if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
+ BitWord EMask = 1UL << (E % BITWORD_SIZE);
+ BitWord IMask = 1UL << (I % BITWORD_SIZE);
+ BitWord Mask = EMask - IMask;
+ Bits[I / BITWORD_SIZE] |= Mask;
+ return *this;
+ }
+
+ BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE);
+ Bits[I / BITWORD_SIZE] |= PrefixMask;
+ I = alignTo(I, BITWORD_SIZE);
+
+ for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
+ Bits[I / BITWORD_SIZE] = ~0UL;
+
+ BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1;
+ if (I < E)
+ Bits[I / BITWORD_SIZE] |= PostfixMask;
+
+ return *this;
+ }
+
+ BitVector &reset() {
+ init_words(Bits, false);
+ return *this;
+ }
+
+ BitVector &reset(unsigned Idx) {
+ Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE));
+ return *this;
+ }
+
+ /// reset - Efficiently reset a range of bits in [I, E)
+ BitVector &reset(unsigned I, unsigned E) {
+ assert(I <= E && "Attempted to reset backwards range!");
+ assert(E <= size() && "Attempted to reset out-of-bounds range!");
+
+ if (I == E) return *this;
+
+ if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
+ BitWord EMask = 1UL << (E % BITWORD_SIZE);
+ BitWord IMask = 1UL << (I % BITWORD_SIZE);
+ BitWord Mask = EMask - IMask;
+ Bits[I / BITWORD_SIZE] &= ~Mask;
+ return *this;
+ }
+
+ BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE);
+ Bits[I / BITWORD_SIZE] &= ~PrefixMask;
+ I = alignTo(I, BITWORD_SIZE);
+
+ for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
+ Bits[I / BITWORD_SIZE] = 0UL;
+
+ BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1;
+ if (I < E)
+ Bits[I / BITWORD_SIZE] &= ~PostfixMask;
+
+ return *this;
+ }
+
+ BitVector &flip() {
+ for (unsigned i = 0; i < NumBitWords(size()); ++i)
+ Bits[i] = ~Bits[i];
+ clear_unused_bits();
+ return *this;
+ }
+
+ BitVector &flip(unsigned Idx) {
+ Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE);
+ return *this;
+ }
+
+ // Indexing.
+ reference operator[](unsigned Idx) {
+ assert (Idx < Size && "Out-of-bounds Bit access.");
+ return reference(*this, Idx);
+ }
+
+ bool operator[](unsigned Idx) const {
+ assert (Idx < Size && "Out-of-bounds Bit access.");
+ BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE);
+ return (Bits[Idx / BITWORD_SIZE] & Mask) != 0;
+ }
+
+ bool test(unsigned Idx) const {
+ return (*this)[Idx];
+ }
+
+ // Push single bit to end of vector.
+ void push_back(bool Val) {
+ unsigned OldSize = Size;
+ unsigned NewSize = Size + 1;
+
+ // Resize, which will insert zeros.
+ // If we already fit then the unused bits will be already zero.
+ if (NewSize > getBitCapacity())
+ resize(NewSize, false);
+ else
+ Size = NewSize;
+
+ // If true, set single bit.
+ if (Val)
+ set(OldSize);
+ }
+
+ /// Test if any common bits are set.
+ bool anyCommon(const BitVector &RHS) const {
+ unsigned ThisWords = NumBitWords(size());
+ unsigned RHSWords = NumBitWords(RHS.size());
+ for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i)
+ if (Bits[i] & RHS.Bits[i])
+ return true;
+ return false;
+ }
+
+ // Comparison operators.
+ bool operator==(const BitVector &RHS) const {
+ unsigned ThisWords = NumBitWords(size());
+ unsigned RHSWords = NumBitWords(RHS.size());
+ unsigned i;
+ for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
+ if (Bits[i] != RHS.Bits[i])
+ return false;
+
+ // Verify that any extra words are all zeros.
+ if (i != ThisWords) {
+ for (; i != ThisWords; ++i)
+ if (Bits[i])
+ return false;
+ } else if (i != RHSWords) {
+ for (; i != RHSWords; ++i)
+ if (RHS.Bits[i])
+ return false;
+ }
+ return true;
+ }
+
+ bool operator!=(const BitVector &RHS) const {
+ return !(*this == RHS);
+ }
+
+ /// Intersection, union, disjoint union.
+ BitVector &operator&=(const BitVector &RHS) {
+ unsigned ThisWords = NumBitWords(size());
+ unsigned RHSWords = NumBitWords(RHS.size());
+ unsigned i;
+ for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
+ Bits[i] &= RHS.Bits[i];
+
+ // Any bits that are just in this bitvector become zero, because they aren't
+ // in the RHS bit vector. Any words only in RHS are ignored because they
+ // are already zero in the LHS.
+ for (; i != ThisWords; ++i)
+ Bits[i] = 0;
+
+ return *this;
+ }
+
+ /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
+ BitVector &reset(const BitVector &RHS) {
+ unsigned ThisWords = NumBitWords(size());
+ unsigned RHSWords = NumBitWords(RHS.size());
+ unsigned i;
+ for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
+ Bits[i] &= ~RHS.Bits[i];
+ return *this;
+ }
+
+ /// test - Check if (This - RHS) is zero.
+ /// This is the same as reset(RHS) and any().
+ bool test(const BitVector &RHS) const {
+ unsigned ThisWords = NumBitWords(size());
+ unsigned RHSWords = NumBitWords(RHS.size());
+ unsigned i;
+ for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
+ if ((Bits[i] & ~RHS.Bits[i]) != 0)
+ return true;
+
+ for (; i != ThisWords ; ++i)
+ if (Bits[i] != 0)
+ return true;
+
+ return false;
+ }
+
+ BitVector &operator|=(const BitVector &RHS) {
+ if (size() < RHS.size())
+ resize(RHS.size());
+ for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
+ Bits[i] |= RHS.Bits[i];
+ return *this;
+ }
+
+ BitVector &operator^=(const BitVector &RHS) {
+ if (size() < RHS.size())
+ resize(RHS.size());
+ for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
+ Bits[i] ^= RHS.Bits[i];
+ return *this;
+ }
+
+ BitVector &operator>>=(unsigned N) {
+ assert(N <= Size);
+ if (LLVM_UNLIKELY(empty() || N == 0))
+ return *this;
+
+ unsigned NumWords = NumBitWords(Size);
+ assert(NumWords >= 1);
+
+ wordShr(N / BITWORD_SIZE);
+
+ unsigned BitDistance = N % BITWORD_SIZE;
+ if (BitDistance == 0)
+ return *this;
+
+ // When the shift size is not a multiple of the word size, then we have
+ // a tricky situation where each word in succession needs to extract some
+ // of the bits from the next word and or them into this word while
+ // shifting this word to make room for the new bits. This has to be done
+ // for every word in the array.
+
+ // Since we're shifting each word right, some bits will fall off the end
+ // of each word to the right, and empty space will be created on the left.
+ // The final word in the array will lose bits permanently, so starting at
+ // the beginning, work forwards shifting each word to the right, and
+ // OR'ing in the bits from the end of the next word to the beginning of
+ // the current word.
+
+ // Example:
+ // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting right
+ // by 4 bits.
+ // Step 1: Word[0] >>= 4 ; 0x0ABBCCDD
+ // Step 2: Word[0] |= 0x10000000 ; 0x1ABBCCDD
+ // Step 3: Word[1] >>= 4 ; 0x0EEFF001
+ // Step 4: Word[1] |= 0x50000000 ; 0x5EEFF001
+ // Step 5: Word[2] >>= 4 ; 0x02334455
+ // Result: { 0x1ABBCCDD, 0x5EEFF001, 0x02334455 }
+ const BitWord Mask = maskTrailingOnes<BitWord>(BitDistance);
+ const unsigned LSH = BITWORD_SIZE - BitDistance;
+
+ for (unsigned I = 0; I < NumWords - 1; ++I) {
+ Bits[I] >>= BitDistance;
+ Bits[I] |= (Bits[I + 1] & Mask) << LSH;
+ }
+
+ Bits[NumWords - 1] >>= BitDistance;
+
+ return *this;
+ }
+
+ BitVector &operator<<=(unsigned N) {
+ assert(N <= Size);
+ if (LLVM_UNLIKELY(empty() || N == 0))
+ return *this;
+
+ unsigned NumWords = NumBitWords(Size);
+ assert(NumWords >= 1);
+
+ wordShl(N / BITWORD_SIZE);
+
+ unsigned BitDistance = N % BITWORD_SIZE;
+ if (BitDistance == 0)
+ return *this;
+
+ // When the shift size is not a multiple of the word size, then we have
+ // a tricky situation where each word in succession needs to extract some
+ // of the bits from the previous word and or them into this word while
+ // shifting this word to make room for the new bits. This has to be done
+ // for every word in the array. This is similar to the algorithm outlined
+ // in operator>>=, but backwards.
+
+ // Since we're shifting each word left, some bits will fall off the end
+ // of each word to the left, and empty space will be created on the right.
+ // The first word in the array will lose bits permanently, so starting at
+ // the end, work backwards shifting each word to the left, and OR'ing
+ // in the bits from the end of the next word to the beginning of the
+ // current word.
+
+ // Example:
+ // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting left
+ // by 4 bits.
+ // Step 1: Word[2] <<= 4 ; 0x23344550
+ // Step 2: Word[2] |= 0x0000000E ; 0x2334455E
+ // Step 3: Word[1] <<= 4 ; 0xEFF00110
+ // Step 4: Word[1] |= 0x0000000A ; 0xEFF0011A
+ // Step 5: Word[0] <<= 4 ; 0xABBCCDD0
+ // Result: { 0xABBCCDD0, 0xEFF0011A, 0x2334455E }
+ const BitWord Mask = maskLeadingOnes<BitWord>(BitDistance);
+ const unsigned RSH = BITWORD_SIZE - BitDistance;
+
+ for (int I = NumWords - 1; I > 0; --I) {
+ Bits[I] <<= BitDistance;
+ Bits[I] |= (Bits[I - 1] & Mask) >> RSH;
+ }
+ Bits[0] <<= BitDistance;
+ clear_unused_bits();
+
+ return *this;
+ }
+
+ // Assignment operator.
+ const BitVector &operator=(const BitVector &RHS) {
+ if (this == &RHS) return *this;
+
+ Size = RHS.size();
+ unsigned RHSWords = NumBitWords(Size);
+ if (Size <= getBitCapacity()) {
+ if (Size)
+ std::memcpy(Bits.data(), RHS.Bits.data(), RHSWords * sizeof(BitWord));
+ clear_unused_bits();
+ return *this;
+ }
+
+ // Grow the bitvector to have enough elements.
+ unsigned NewCapacity = RHSWords;
+ assert(NewCapacity > 0 && "negative capacity?");
+ auto NewBits = allocate(NewCapacity);
+ std::memcpy(NewBits.data(), RHS.Bits.data(), NewCapacity * sizeof(BitWord));
+
+ // Destroy the old bits.
+ std::free(Bits.data());
+ Bits = NewBits;
+
+ return *this;
+ }
+
+ const BitVector &operator=(BitVector &&RHS) {
+ if (this == &RHS) return *this;
+
+ std::free(Bits.data());
+ Bits = RHS.Bits;
+ Size = RHS.Size;
+
+ RHS.Bits = MutableArrayRef<BitWord>();
+ RHS.Size = 0;
+
+ return *this;
+ }
+
+ void swap(BitVector &RHS) {
+ std::swap(Bits, RHS.Bits);
+ std::swap(Size, RHS.Size);
+ }
+
+ //===--------------------------------------------------------------------===//
+ // Portable bit mask operations.
+ //===--------------------------------------------------------------------===//
+ //
+ // These methods all operate on arrays of uint32_t, each holding 32 bits. The
+ // fixed word size makes it easier to work with literal bit vector constants
+ // in portable code.
+ //
+ // The LSB in each word is the lowest numbered bit. The size of a portable
+ // bit mask is always a whole multiple of 32 bits. If no bit mask size is
+ // given, the bit mask is assumed to cover the entire BitVector.
+
+ /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize.
+ /// This computes "*this |= Mask".
+ void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+ applyMask<true, false>(Mask, MaskWords);
+ }
+
+ /// clearBitsInMask - Clear any bits in this vector that are set in Mask.
+ /// Don't resize. This computes "*this &= ~Mask".
+ void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+ applyMask<false, false>(Mask, MaskWords);
+ }
+
+ /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask.
+ /// Don't resize. This computes "*this |= ~Mask".
+ void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+ applyMask<true, true>(Mask, MaskWords);
+ }
+
+ /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask.
+ /// Don't resize. This computes "*this &= Mask".
+ void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
+ applyMask<false, true>(Mask, MaskWords);
+ }
+
+private:
+ /// Perform a logical left shift of \p Count words by moving everything
+ /// \p Count words to the right in memory.
+ ///
+ /// While confusing, words are stored from least significant at Bits[0] to
+ /// most significant at Bits[NumWords-1]. A logical shift left, however,
+ /// moves the current least significant bit to a higher logical index, and
+ /// fills the previous least significant bits with 0. Thus, we actually
+ /// need to move the bytes of the memory to the right, not to the left.
+ /// Example:
+ /// Words = [0xBBBBAAAA, 0xDDDDFFFF, 0x00000000, 0xDDDD0000]
+ /// represents a BitVector where 0xBBBBAAAA contain the least significant
+ /// bits. So if we want to shift the BitVector left by 2 words, we need to
+ /// turn this into 0x00000000 0x00000000 0xBBBBAAAA 0xDDDDFFFF by using a
+ /// memmove which moves right, not left.
+ void wordShl(uint32_t Count) {
+ if (Count == 0)
+ return;
+
+ uint32_t NumWords = NumBitWords(Size);
+
+ auto Src = Bits.take_front(NumWords).drop_back(Count);
+ auto Dest = Bits.take_front(NumWords).drop_front(Count);
+
+ // Since we always move Word-sized chunks of data with src and dest both
+ // aligned to a word-boundary, we don't need to worry about endianness
+ // here.
+ std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
+ std::memset(Bits.data(), 0, Count * sizeof(BitWord));
+ clear_unused_bits();
+ }
+
+ /// Perform a logical right shift of \p Count words by moving those
+ /// words to the left in memory. See wordShl for more information.
+ ///
+ void wordShr(uint32_t Count) {
+ if (Count == 0)
+ return;
+
+ uint32_t NumWords = NumBitWords(Size);
+
+ auto Src = Bits.take_front(NumWords).drop_front(Count);
+ auto Dest = Bits.take_front(NumWords).drop_back(Count);
+ assert(Dest.size() == Src.size());
+
+ std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
+ std::memset(Dest.end(), 0, Count * sizeof(BitWord));
+ }
+
+ MutableArrayRef<BitWord> allocate(size_t NumWords) {
+ BitWord *RawBits = static_cast<BitWord *>(
+ safe_malloc(NumWords * sizeof(BitWord)));
+ return MutableArrayRef<BitWord>(RawBits, NumWords);
+ }
+
+ int next_unset_in_word(int WordIndex, BitWord Word) const {
+ unsigned Result = WordIndex * BITWORD_SIZE + countTrailingOnes(Word);
+ return Result < size() ? Result : -1;
+ }
+
+ unsigned NumBitWords(unsigned S) const {
+ return (S + BITWORD_SIZE-1) / BITWORD_SIZE;
+ }
+
+ // Set the unused bits in the high words.
+ void set_unused_bits(bool t = true) {
+ // Set high words first.
+ unsigned UsedWords = NumBitWords(Size);
+ if (Bits.size() > UsedWords)
+ init_words(Bits.drop_front(UsedWords), t);
+
+ // Then set any stray high bits of the last used word.
+ unsigned ExtraBits = Size % BITWORD_SIZE;
+ if (ExtraBits) {
+ BitWord ExtraBitMask = ~0UL << ExtraBits;
+ if (t)
+ Bits[UsedWords-1] |= ExtraBitMask;
+ else
+ Bits[UsedWords-1] &= ~ExtraBitMask;
+ }
+ }
+
+ // Clear the unused bits in the high words.
+ void clear_unused_bits() {
+ set_unused_bits(false);
+ }
+
+ void grow(unsigned NewSize) {
+ size_t NewCapacity = std::max<size_t>(NumBitWords(NewSize), Bits.size() * 2);
+ assert(NewCapacity > 0 && "realloc-ing zero space");
+ BitWord *NewBits = static_cast<BitWord *>(
+ safe_realloc(Bits.data(), NewCapacity * sizeof(BitWord)));
+ Bits = MutableArrayRef<BitWord>(NewBits, NewCapacity);
+ clear_unused_bits();
+ }
+
+ void init_words(MutableArrayRef<BitWord> B, bool t) {
+ if (B.size() > 0)
+ memset(B.data(), 0 - (int)t, B.size() * sizeof(BitWord));
+ }
+
+ template<bool AddBits, bool InvertMask>
+ void applyMask(const uint32_t *Mask, unsigned MaskWords) {
+ static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size.");
+ MaskWords = std::min(MaskWords, (size() + 31) / 32);
+ const unsigned Scale = BITWORD_SIZE / 32;
+ unsigned i;
+ for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) {
+ BitWord BW = Bits[i];
+ // This inner loop should unroll completely when BITWORD_SIZE > 32.
+ for (unsigned b = 0; b != BITWORD_SIZE; b += 32) {
+ uint32_t M = *Mask++;
+ if (InvertMask) M = ~M;
+ if (AddBits) BW |= BitWord(M) << b;
+ else BW &= ~(BitWord(M) << b);
+ }
+ Bits[i] = BW;
+ }
+ for (unsigned b = 0; MaskWords; b += 32, --MaskWords) {
+ uint32_t M = *Mask++;
+ if (InvertMask) M = ~M;
+ if (AddBits) Bits[i] |= BitWord(M) << b;
+ else Bits[i] &= ~(BitWord(M) << b);
+ }
+ if (AddBits)
+ clear_unused_bits();
+ }
+
+public:
+ /// Return the size (in bytes) of the bit vector.
+ size_t getMemorySize() const { return Bits.size() * sizeof(BitWord); }
+ size_t getBitCapacity() const { return Bits.size() * BITWORD_SIZE; }
+};
+
+inline size_t capacity_in_bytes(const BitVector &X) {
+ return X.getMemorySize();
+}
+
+} // end namespace llvm
+
+namespace std {
+ /// Implement std::swap in terms of BitVector swap.
+ inline void
+ swap(llvm::BitVector &LHS, llvm::BitVector &RHS) {
+ LHS.swap(RHS);
+ }
+} // end namespace std
+
+#endif // LLVM_ADT_BITVECTOR_H
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