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+//===- llvm/ADT/SparseBitVector.h - Efficient Sparse BitVector --*- 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 defines the SparseBitVector class. See the doxygen comment for
+// SparseBitVector for more details on the algorithm used.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_SPARSEBITVECTOR_H
+#define LLVM_ADT_SPARSEBITVECTOR_H
+
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+#include <climits>
+#include <cstring>
+#include <iterator>
+#include <list>
+
+namespace llvm {
+
+/// SparseBitVector is an implementation of a bitvector that is sparse by only
+/// storing the elements that have non-zero bits set. In order to make this
+/// fast for the most common cases, SparseBitVector is implemented as a linked
+/// list of SparseBitVectorElements. We maintain a pointer to the last
+/// SparseBitVectorElement accessed (in the form of a list iterator), in order
+/// to make multiple in-order test/set constant time after the first one is
+/// executed. Note that using vectors to store SparseBitVectorElement's does
+/// not work out very well because it causes insertion in the middle to take
+/// enormous amounts of time with a large amount of bits. Other structures that
+/// have better worst cases for insertion in the middle (various balanced trees,
+/// etc) do not perform as well in practice as a linked list with this iterator
+/// kept up to date. They are also significantly more memory intensive.
+
+template <unsigned ElementSize = 128> struct SparseBitVectorElement {
+public:
+ using BitWord = unsigned long;
+ using size_type = unsigned;
+ enum {
+ BITWORD_SIZE = sizeof(BitWord) * CHAR_BIT,
+ BITWORDS_PER_ELEMENT = (ElementSize + BITWORD_SIZE - 1) / BITWORD_SIZE,
+ BITS_PER_ELEMENT = ElementSize
+ };
+
+private:
+ // Index of Element in terms of where first bit starts.
+ unsigned ElementIndex;
+ BitWord Bits[BITWORDS_PER_ELEMENT];
+
+ SparseBitVectorElement() {
+ ElementIndex = ~0U;
+ memset(&Bits[0], 0, sizeof (BitWord) * BITWORDS_PER_ELEMENT);
+ }
+
+public:
+ explicit SparseBitVectorElement(unsigned Idx) {
+ ElementIndex = Idx;
+ memset(&Bits[0], 0, sizeof (BitWord) * BITWORDS_PER_ELEMENT);
+ }
+
+ // Comparison.
+ bool operator==(const SparseBitVectorElement &RHS) const {
+ if (ElementIndex != RHS.ElementIndex)
+ return false;
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i)
+ if (Bits[i] != RHS.Bits[i])
+ return false;
+ return true;
+ }
+
+ bool operator!=(const SparseBitVectorElement &RHS) const {
+ return !(*this == RHS);
+ }
+
+ // Return the bits that make up word Idx in our element.
+ BitWord word(unsigned Idx) const {
+ assert(Idx < BITWORDS_PER_ELEMENT);
+ return Bits[Idx];
+ }
+
+ unsigned index() const {
+ return ElementIndex;
+ }
+
+ bool empty() const {
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i)
+ if (Bits[i])
+ return false;
+ return true;
+ }
+
+ void set(unsigned Idx) {
+ Bits[Idx / BITWORD_SIZE] |= 1L << (Idx % BITWORD_SIZE);
+ }
+
+ bool test_and_set(unsigned Idx) {
+ bool old = test(Idx);
+ if (!old) {
+ set(Idx);
+ return true;
+ }
+ return false;
+ }
+
+ void reset(unsigned Idx) {
+ Bits[Idx / BITWORD_SIZE] &= ~(1L << (Idx % BITWORD_SIZE));
+ }
+
+ bool test(unsigned Idx) const {
+ return Bits[Idx / BITWORD_SIZE] & (1L << (Idx % BITWORD_SIZE));
+ }
+
+ size_type count() const {
+ unsigned NumBits = 0;
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i)
+ NumBits += countPopulation(Bits[i]);
+ return NumBits;
+ }
+
+ /// find_first - Returns the index of the first set bit.
+ int find_first() const {
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i)
+ if (Bits[i] != 0)
+ return i * BITWORD_SIZE + countTrailingZeros(Bits[i]);
+ llvm_unreachable("Illegal empty element");
+ }
+
+ /// find_last - Returns the index of the last set bit.
+ int find_last() const {
+ for (unsigned I = 0; I < BITWORDS_PER_ELEMENT; ++I) {
+ unsigned Idx = BITWORDS_PER_ELEMENT - I - 1;
+ if (Bits[Idx] != 0)
+ return Idx * BITWORD_SIZE + BITWORD_SIZE -
+ countLeadingZeros(Bits[Idx]) - 1;
+ }
+ llvm_unreachable("Illegal empty element");
+ }
+
+ /// find_next - Returns the index of the next set bit starting from the
+ /// "Curr" bit. Returns -1 if the next set bit is not found.
+ int find_next(unsigned Curr) const {
+ if (Curr >= BITS_PER_ELEMENT)
+ return -1;
+
+ unsigned WordPos = Curr / BITWORD_SIZE;
+ unsigned BitPos = Curr % BITWORD_SIZE;
+ BitWord Copy = Bits[WordPos];
+ assert(WordPos <= BITWORDS_PER_ELEMENT
+ && "Word Position outside of element");
+
+ // Mask off previous bits.
+ Copy &= ~0UL << BitPos;
+
+ if (Copy != 0)
+ return WordPos * BITWORD_SIZE + countTrailingZeros(Copy);
+
+ // Check subsequent words.
+ for (unsigned i = WordPos+1; i < BITWORDS_PER_ELEMENT; ++i)
+ if (Bits[i] != 0)
+ return i * BITWORD_SIZE + countTrailingZeros(Bits[i]);
+ return -1;
+ }
+
+ // Union this element with RHS and return true if this one changed.
+ bool unionWith(const SparseBitVectorElement &RHS) {
+ bool changed = false;
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i) {
+ BitWord old = changed ? 0 : Bits[i];
+
+ Bits[i] |= RHS.Bits[i];
+ if (!changed && old != Bits[i])
+ changed = true;
+ }
+ return changed;
+ }
+
+ // Return true if we have any bits in common with RHS
+ bool intersects(const SparseBitVectorElement &RHS) const {
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i) {
+ if (RHS.Bits[i] & Bits[i])
+ return true;
+ }
+ return false;
+ }
+
+ // Intersect this Element with RHS and return true if this one changed.
+ // BecameZero is set to true if this element became all-zero bits.
+ bool intersectWith(const SparseBitVectorElement &RHS,
+ bool &BecameZero) {
+ bool changed = false;
+ bool allzero = true;
+
+ BecameZero = false;
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i) {
+ BitWord old = changed ? 0 : Bits[i];
+
+ Bits[i] &= RHS.Bits[i];
+ if (Bits[i] != 0)
+ allzero = false;
+
+ if (!changed && old != Bits[i])
+ changed = true;
+ }
+ BecameZero = allzero;
+ return changed;
+ }
+
+ // Intersect this Element with the complement of RHS and return true if this
+ // one changed. BecameZero is set to true if this element became all-zero
+ // bits.
+ bool intersectWithComplement(const SparseBitVectorElement &RHS,
+ bool &BecameZero) {
+ bool changed = false;
+ bool allzero = true;
+
+ BecameZero = false;
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i) {
+ BitWord old = changed ? 0 : Bits[i];
+
+ Bits[i] &= ~RHS.Bits[i];
+ if (Bits[i] != 0)
+ allzero = false;
+
+ if (!changed && old != Bits[i])
+ changed = true;
+ }
+ BecameZero = allzero;
+ return changed;
+ }
+
+ // Three argument version of intersectWithComplement that intersects
+ // RHS1 & ~RHS2 into this element
+ void intersectWithComplement(const SparseBitVectorElement &RHS1,
+ const SparseBitVectorElement &RHS2,
+ bool &BecameZero) {
+ bool allzero = true;
+
+ BecameZero = false;
+ for (unsigned i = 0; i < BITWORDS_PER_ELEMENT; ++i) {
+ Bits[i] = RHS1.Bits[i] & ~RHS2.Bits[i];
+ if (Bits[i] != 0)
+ allzero = false;
+ }
+ BecameZero = allzero;
+ }
+};
+
+template <unsigned ElementSize = 128>
+class SparseBitVector {
+ using ElementList = std::list<SparseBitVectorElement<ElementSize>>;
+ using ElementListIter = typename ElementList::iterator;
+ using ElementListConstIter = typename ElementList::const_iterator;
+ enum {
+ BITWORD_SIZE = SparseBitVectorElement<ElementSize>::BITWORD_SIZE
+ };
+
+ ElementList Elements;
+ // Pointer to our current Element. This has no visible effect on the external
+ // state of a SparseBitVector, it's just used to improve performance in the
+ // common case of testing/modifying bits with similar indices.
+ mutable ElementListIter CurrElementIter;
+
+ // This is like std::lower_bound, except we do linear searching from the
+ // current position.
+ ElementListIter FindLowerBoundImpl(unsigned ElementIndex) const {
+
+ // We cache a non-const iterator so we're forced to resort to const_cast to
+ // get the begin/end in the case where 'this' is const. To avoid duplication
+ // of code with the only difference being whether the const cast is present
+ // 'this' is always const in this particular function and we sort out the
+ // difference in FindLowerBound and FindLowerBoundConst.
+ ElementListIter Begin =
+ const_cast<SparseBitVector<ElementSize> *>(this)->Elements.begin();
+ ElementListIter End =
+ const_cast<SparseBitVector<ElementSize> *>(this)->Elements.end();
+
+ if (Elements.empty()) {
+ CurrElementIter = Begin;
+ return CurrElementIter;
+ }
+
+ // Make sure our current iterator is valid.
+ if (CurrElementIter == End)
+ --CurrElementIter;
+
+ // Search from our current iterator, either backwards or forwards,
+ // depending on what element we are looking for.
+ ElementListIter ElementIter = CurrElementIter;
+ if (CurrElementIter->index() == ElementIndex) {
+ return ElementIter;
+ } else if (CurrElementIter->index() > ElementIndex) {
+ while (ElementIter != Begin
+ && ElementIter->index() > ElementIndex)
+ --ElementIter;
+ } else {
+ while (ElementIter != End &&
+ ElementIter->index() < ElementIndex)
+ ++ElementIter;
+ }
+ CurrElementIter = ElementIter;
+ return ElementIter;
+ }
+ ElementListConstIter FindLowerBoundConst(unsigned ElementIndex) const {
+ return FindLowerBoundImpl(ElementIndex);
+ }
+ ElementListIter FindLowerBound(unsigned ElementIndex) {
+ return FindLowerBoundImpl(ElementIndex);
+ }
+
+ // Iterator to walk set bits in the bitmap. This iterator is a lot uglier
+ // than it would be, in order to be efficient.
+ class SparseBitVectorIterator {
+ private:
+ bool AtEnd;
+
+ const SparseBitVector<ElementSize> *BitVector = nullptr;
+
+ // Current element inside of bitmap.
+ ElementListConstIter Iter;
+
+ // Current bit number inside of our bitmap.
+ unsigned BitNumber;
+
+ // Current word number inside of our element.
+ unsigned WordNumber;
+
+ // Current bits from the element.
+ typename SparseBitVectorElement<ElementSize>::BitWord Bits;
+
+ // Move our iterator to the first non-zero bit in the bitmap.
+ void AdvanceToFirstNonZero() {
+ if (AtEnd)
+ return;
+ if (BitVector->Elements.empty()) {
+ AtEnd = true;
+ return;
+ }
+ Iter = BitVector->Elements.begin();
+ BitNumber = Iter->index() * ElementSize;
+ unsigned BitPos = Iter->find_first();
+ BitNumber += BitPos;
+ WordNumber = (BitNumber % ElementSize) / BITWORD_SIZE;
+ Bits = Iter->word(WordNumber);
+ Bits >>= BitPos % BITWORD_SIZE;
+ }
+
+ // Move our iterator to the next non-zero bit.
+ void AdvanceToNextNonZero() {
+ if (AtEnd)
+ return;
+
+ while (Bits && !(Bits & 1)) {
+ Bits >>= 1;
+ BitNumber += 1;
+ }
+
+ // See if we ran out of Bits in this word.
+ if (!Bits) {
+ int NextSetBitNumber = Iter->find_next(BitNumber % ElementSize) ;
+ // If we ran out of set bits in this element, move to next element.
+ if (NextSetBitNumber == -1 || (BitNumber % ElementSize == 0)) {
+ ++Iter;
+ WordNumber = 0;
+
+ // We may run out of elements in the bitmap.
+ if (Iter == BitVector->Elements.end()) {
+ AtEnd = true;
+ return;
+ }
+ // Set up for next non-zero word in bitmap.
+ BitNumber = Iter->index() * ElementSize;
+ NextSetBitNumber = Iter->find_first();
+ BitNumber += NextSetBitNumber;
+ WordNumber = (BitNumber % ElementSize) / BITWORD_SIZE;
+ Bits = Iter->word(WordNumber);
+ Bits >>= NextSetBitNumber % BITWORD_SIZE;
+ } else {
+ WordNumber = (NextSetBitNumber % ElementSize) / BITWORD_SIZE;
+ Bits = Iter->word(WordNumber);
+ Bits >>= NextSetBitNumber % BITWORD_SIZE;
+ BitNumber = Iter->index() * ElementSize;
+ BitNumber += NextSetBitNumber;
+ }
+ }
+ }
+
+ public:
+ SparseBitVectorIterator() = default;
+
+ SparseBitVectorIterator(const SparseBitVector<ElementSize> *RHS,
+ bool end = false):BitVector(RHS) {
+ Iter = BitVector->Elements.begin();
+ BitNumber = 0;
+ Bits = 0;
+ WordNumber = ~0;
+ AtEnd = end;
+ AdvanceToFirstNonZero();
+ }
+
+ // Preincrement.
+ inline SparseBitVectorIterator& operator++() {
+ ++BitNumber;
+ Bits >>= 1;
+ AdvanceToNextNonZero();
+ return *this;
+ }
+
+ // Postincrement.
+ inline SparseBitVectorIterator operator++(int) {
+ SparseBitVectorIterator tmp = *this;
+ ++*this;
+ return tmp;
+ }
+
+ // Return the current set bit number.
+ unsigned operator*() const {
+ return BitNumber;
+ }
+
+ bool operator==(const SparseBitVectorIterator &RHS) const {
+ // If they are both at the end, ignore the rest of the fields.
+ if (AtEnd && RHS.AtEnd)
+ return true;
+ // Otherwise they are the same if they have the same bit number and
+ // bitmap.
+ return AtEnd == RHS.AtEnd && RHS.BitNumber == BitNumber;
+ }
+
+ bool operator!=(const SparseBitVectorIterator &RHS) const {
+ return !(*this == RHS);
+ }
+ };
+
+public:
+ using iterator = SparseBitVectorIterator;
+
+ SparseBitVector() : Elements(), CurrElementIter(Elements.begin()) {}
+
+ SparseBitVector(const SparseBitVector &RHS)
+ : Elements(RHS.Elements), CurrElementIter(Elements.begin()) {}
+ SparseBitVector(SparseBitVector &&RHS)
+ : Elements(std::move(RHS.Elements)), CurrElementIter(Elements.begin()) {}
+
+ // Clear.
+ void clear() {
+ Elements.clear();
+ }
+
+ // Assignment
+ SparseBitVector& operator=(const SparseBitVector& RHS) {
+ if (this == &RHS)
+ return *this;
+
+ Elements = RHS.Elements;
+ CurrElementIter = Elements.begin();
+ return *this;
+ }
+ SparseBitVector &operator=(SparseBitVector &&RHS) {
+ Elements = std::move(RHS.Elements);
+ CurrElementIter = Elements.begin();
+ return *this;
+ }
+
+ // Test, Reset, and Set a bit in the bitmap.
+ bool test(unsigned Idx) const {
+ if (Elements.empty())
+ return false;
+
+ unsigned ElementIndex = Idx / ElementSize;
+ ElementListConstIter ElementIter = FindLowerBoundConst(ElementIndex);
+
+ // If we can't find an element that is supposed to contain this bit, there
+ // is nothing more to do.
+ if (ElementIter == Elements.end() ||
+ ElementIter->index() != ElementIndex)
+ return false;
+ return ElementIter->test(Idx % ElementSize);
+ }
+
+ void reset(unsigned Idx) {
+ if (Elements.empty())
+ return;
+
+ unsigned ElementIndex = Idx / ElementSize;
+ ElementListIter ElementIter = FindLowerBound(ElementIndex);
+
+ // If we can't find an element that is supposed to contain this bit, there
+ // is nothing more to do.
+ if (ElementIter == Elements.end() ||
+ ElementIter->index() != ElementIndex)
+ return;
+ ElementIter->reset(Idx % ElementSize);
+
+ // When the element is zeroed out, delete it.
+ if (ElementIter->empty()) {
+ ++CurrElementIter;
+ Elements.erase(ElementIter);
+ }
+ }
+
+ void set(unsigned Idx) {
+ unsigned ElementIndex = Idx / ElementSize;
+ ElementListIter ElementIter;
+ if (Elements.empty()) {
+ ElementIter = Elements.emplace(Elements.end(), ElementIndex);
+ } else {
+ ElementIter = FindLowerBound(ElementIndex);
+
+ if (ElementIter == Elements.end() ||
+ ElementIter->index() != ElementIndex) {
+ // We may have hit the beginning of our SparseBitVector, in which case,
+ // we may need to insert right after this element, which requires moving
+ // the current iterator forward one, because insert does insert before.
+ if (ElementIter != Elements.end() &&
+ ElementIter->index() < ElementIndex)
+ ++ElementIter;
+ ElementIter = Elements.emplace(ElementIter, ElementIndex);
+ }
+ }
+ CurrElementIter = ElementIter;
+
+ ElementIter->set(Idx % ElementSize);
+ }
+
+ bool test_and_set(unsigned Idx) {
+ bool old = test(Idx);
+ if (!old) {
+ set(Idx);
+ return true;
+ }
+ return false;
+ }
+
+ bool operator!=(const SparseBitVector &RHS) const {
+ return !(*this == RHS);
+ }
+
+ bool operator==(const SparseBitVector &RHS) const {
+ ElementListConstIter Iter1 = Elements.begin();
+ ElementListConstIter Iter2 = RHS.Elements.begin();
+
+ for (; Iter1 != Elements.end() && Iter2 != RHS.Elements.end();
+ ++Iter1, ++Iter2) {
+ if (*Iter1 != *Iter2)
+ return false;
+ }
+ return Iter1 == Elements.end() && Iter2 == RHS.Elements.end();
+ }
+
+ // Union our bitmap with the RHS and return true if we changed.
+ bool operator|=(const SparseBitVector &RHS) {
+ if (this == &RHS)
+ return false;
+
+ bool changed = false;
+ ElementListIter Iter1 = Elements.begin();
+ ElementListConstIter Iter2 = RHS.Elements.begin();
+
+ // If RHS is empty, we are done
+ if (RHS.Elements.empty())
+ return false;
+
+ while (Iter2 != RHS.Elements.end()) {
+ if (Iter1 == Elements.end() || Iter1->index() > Iter2->index()) {
+ Elements.insert(Iter1, *Iter2);
+ ++Iter2;
+ changed = true;
+ } else if (Iter1->index() == Iter2->index()) {
+ changed |= Iter1->unionWith(*Iter2);
+ ++Iter1;
+ ++Iter2;
+ } else {
+ ++Iter1;
+ }
+ }
+ CurrElementIter = Elements.begin();
+ return changed;
+ }
+
+ // Intersect our bitmap with the RHS and return true if ours changed.
+ bool operator&=(const SparseBitVector &RHS) {
+ if (this == &RHS)
+ return false;
+
+ bool changed = false;
+ ElementListIter Iter1 = Elements.begin();
+ ElementListConstIter Iter2 = RHS.Elements.begin();
+
+ // Check if both bitmaps are empty.
+ if (Elements.empty() && RHS.Elements.empty())
+ return false;
+
+ // Loop through, intersecting as we go, erasing elements when necessary.
+ while (Iter2 != RHS.Elements.end()) {
+ if (Iter1 == Elements.end()) {
+ CurrElementIter = Elements.begin();
+ return changed;
+ }
+
+ if (Iter1->index() > Iter2->index()) {
+ ++Iter2;
+ } else if (Iter1->index() == Iter2->index()) {
+ bool BecameZero;
+ changed |= Iter1->intersectWith(*Iter2, BecameZero);
+ if (BecameZero) {
+ ElementListIter IterTmp = Iter1;
+ ++Iter1;
+ Elements.erase(IterTmp);
+ } else {
+ ++Iter1;
+ }
+ ++Iter2;
+ } else {
+ ElementListIter IterTmp = Iter1;
+ ++Iter1;
+ Elements.erase(IterTmp);
+ changed = true;
+ }
+ }
+ if (Iter1 != Elements.end()) {
+ Elements.erase(Iter1, Elements.end());
+ changed = true;
+ }
+ CurrElementIter = Elements.begin();
+ return changed;
+ }
+
+ // Intersect our bitmap with the complement of the RHS and return true
+ // if ours changed.
+ bool intersectWithComplement(const SparseBitVector &RHS) {
+ if (this == &RHS) {
+ if (!empty()) {
+ clear();
+ return true;
+ }
+ return false;
+ }
+
+ bool changed = false;
+ ElementListIter Iter1 = Elements.begin();
+ ElementListConstIter Iter2 = RHS.Elements.begin();
+
+ // If either our bitmap or RHS is empty, we are done
+ if (Elements.empty() || RHS.Elements.empty())
+ return false;
+
+ // Loop through, intersecting as we go, erasing elements when necessary.
+ while (Iter2 != RHS.Elements.end()) {
+ if (Iter1 == Elements.end()) {
+ CurrElementIter = Elements.begin();
+ return changed;
+ }
+
+ if (Iter1->index() > Iter2->index()) {
+ ++Iter2;
+ } else if (Iter1->index() == Iter2->index()) {
+ bool BecameZero;
+ changed |= Iter1->intersectWithComplement(*Iter2, BecameZero);
+ if (BecameZero) {
+ ElementListIter IterTmp = Iter1;
+ ++Iter1;
+ Elements.erase(IterTmp);
+ } else {
+ ++Iter1;
+ }
+ ++Iter2;
+ } else {
+ ++Iter1;
+ }
+ }
+ CurrElementIter = Elements.begin();
+ return changed;
+ }
+
+ bool intersectWithComplement(const SparseBitVector<ElementSize> *RHS) const {
+ return intersectWithComplement(*RHS);
+ }
+
+ // Three argument version of intersectWithComplement.
+ // Result of RHS1 & ~RHS2 is stored into this bitmap.
+ void intersectWithComplement(const SparseBitVector<ElementSize> &RHS1,
+ const SparseBitVector<ElementSize> &RHS2)
+ {
+ if (this == &RHS1) {
+ intersectWithComplement(RHS2);
+ return;
+ } else if (this == &RHS2) {
+ SparseBitVector RHS2Copy(RHS2);
+ intersectWithComplement(RHS1, RHS2Copy);
+ return;
+ }
+
+ Elements.clear();
+ CurrElementIter = Elements.begin();
+ ElementListConstIter Iter1 = RHS1.Elements.begin();
+ ElementListConstIter Iter2 = RHS2.Elements.begin();
+
+ // If RHS1 is empty, we are done
+ // If RHS2 is empty, we still have to copy RHS1
+ if (RHS1.Elements.empty())
+ return;
+
+ // Loop through, intersecting as we go, erasing elements when necessary.
+ while (Iter2 != RHS2.Elements.end()) {
+ if (Iter1 == RHS1.Elements.end())
+ return;
+
+ if (Iter1->index() > Iter2->index()) {
+ ++Iter2;
+ } else if (Iter1->index() == Iter2->index()) {
+ bool BecameZero = false;
+ Elements.emplace_back(Iter1->index());
+ Elements.back().intersectWithComplement(*Iter1, *Iter2, BecameZero);
+ if (BecameZero)
+ Elements.pop_back();
+ ++Iter1;
+ ++Iter2;
+ } else {
+ Elements.push_back(*Iter1++);
+ }
+ }
+
+ // copy the remaining elements
+ std::copy(Iter1, RHS1.Elements.end(), std::back_inserter(Elements));
+ }
+
+ void intersectWithComplement(const SparseBitVector<ElementSize> *RHS1,
+ const SparseBitVector<ElementSize> *RHS2) {
+ intersectWithComplement(*RHS1, *RHS2);
+ }
+
+ bool intersects(const SparseBitVector<ElementSize> *RHS) const {
+ return intersects(*RHS);
+ }
+
+ // Return true if we share any bits in common with RHS
+ bool intersects(const SparseBitVector<ElementSize> &RHS) const {
+ ElementListConstIter Iter1 = Elements.begin();
+ ElementListConstIter Iter2 = RHS.Elements.begin();
+
+ // Check if both bitmaps are empty.
+ if (Elements.empty() && RHS.Elements.empty())
+ return false;
+
+ // Loop through, intersecting stopping when we hit bits in common.
+ while (Iter2 != RHS.Elements.end()) {
+ if (Iter1 == Elements.end())
+ return false;
+
+ if (Iter1->index() > Iter2->index()) {
+ ++Iter2;
+ } else if (Iter1->index() == Iter2->index()) {
+ if (Iter1->intersects(*Iter2))
+ return true;
+ ++Iter1;
+ ++Iter2;
+ } else {
+ ++Iter1;
+ }
+ }
+ return false;
+ }
+
+ // Return true iff all bits set in this SparseBitVector are
+ // also set in RHS.
+ bool contains(const SparseBitVector<ElementSize> &RHS) const {
+ SparseBitVector<ElementSize> Result(*this);
+ Result &= RHS;
+ return (Result == RHS);
+ }
+
+ // Return the first set bit in the bitmap. Return -1 if no bits are set.
+ int find_first() const {
+ if (Elements.empty())
+ return -1;
+ const SparseBitVectorElement<ElementSize> &First = *(Elements.begin());
+ return (First.index() * ElementSize) + First.find_first();
+ }
+
+ // Return the last set bit in the bitmap. Return -1 if no bits are set.
+ int find_last() const {
+ if (Elements.empty())
+ return -1;
+ const SparseBitVectorElement<ElementSize> &Last = *(Elements.rbegin());
+ return (Last.index() * ElementSize) + Last.find_last();
+ }
+
+ // Return true if the SparseBitVector is empty
+ bool empty() const {
+ return Elements.empty();
+ }
+
+ unsigned count() const {
+ unsigned BitCount = 0;
+ for (ElementListConstIter Iter = Elements.begin();
+ Iter != Elements.end();
+ ++Iter)
+ BitCount += Iter->count();
+
+ return BitCount;
+ }
+
+ iterator begin() const {
+ return iterator(this);
+ }
+
+ iterator end() const {
+ return iterator(this, true);
+ }
+};
+
+// Convenience functions to allow Or and And without dereferencing in the user
+// code.
+
+template <unsigned ElementSize>
+inline bool operator |=(SparseBitVector<ElementSize> &LHS,
+ const SparseBitVector<ElementSize> *RHS) {
+ return LHS |= *RHS;
+}
+
+template <unsigned ElementSize>
+inline bool operator |=(SparseBitVector<ElementSize> *LHS,
+ const SparseBitVector<ElementSize> &RHS) {
+ return LHS->operator|=(RHS);
+}
+
+template <unsigned ElementSize>
+inline bool operator &=(SparseBitVector<ElementSize> *LHS,
+ const SparseBitVector<ElementSize> &RHS) {
+ return LHS->operator&=(RHS);
+}
+
+template <unsigned ElementSize>
+inline bool operator &=(SparseBitVector<ElementSize> &LHS,
+ const SparseBitVector<ElementSize> *RHS) {
+ return LHS &= *RHS;
+}
+
+// Convenience functions for infix union, intersection, difference operators.
+
+template <unsigned ElementSize>
+inline SparseBitVector<ElementSize>
+operator|(const SparseBitVector<ElementSize> &LHS,
+ const SparseBitVector<ElementSize> &RHS) {
+ SparseBitVector<ElementSize> Result(LHS);
+ Result |= RHS;
+ return Result;
+}
+
+template <unsigned ElementSize>
+inline SparseBitVector<ElementSize>
+operator&(const SparseBitVector<ElementSize> &LHS,
+ const SparseBitVector<ElementSize> &RHS) {
+ SparseBitVector<ElementSize> Result(LHS);
+ Result &= RHS;
+ return Result;
+}
+
+template <unsigned ElementSize>
+inline SparseBitVector<ElementSize>
+operator-(const SparseBitVector<ElementSize> &LHS,
+ const SparseBitVector<ElementSize> &RHS) {
+ SparseBitVector<ElementSize> Result;
+ Result.intersectWithComplement(LHS, RHS);
+ return Result;
+}
+
+// Dump a SparseBitVector to a stream
+template <unsigned ElementSize>
+void dump(const SparseBitVector<ElementSize> &LHS, raw_ostream &out) {
+ out << "[";
+
+ typename SparseBitVector<ElementSize>::iterator bi = LHS.begin(),
+ be = LHS.end();
+ if (bi != be) {
+ out << *bi;
+ for (++bi; bi != be; ++bi) {
+ out << " " << *bi;
+ }
+ }
+ out << "]\n";
+}
+
+} // end namespace llvm
+
+#endif // LLVM_ADT_SPARSEBITVECTOR_H
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