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1//===-- sanitizer_bitvector.h -----------------------------------*- 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-exception6//7//===----------------------------------------------------------------------===//8//9// Specializer BitVector implementation.10//11//===----------------------------------------------------------------------===//12 13#ifndef SANITIZER_BITVECTOR_H14#define SANITIZER_BITVECTOR_H15 16#include "sanitizer_common.h"17 18namespace __sanitizer {19 20// Fixed size bit vector based on a single basic integer.21template <class basic_int_t = uptr>22class BasicBitVector {23 public:24 enum SizeEnum : uptr { kSize = sizeof(basic_int_t) * 8 };25 26 uptr size() const { return kSize; }27 // No CTOR.28 void clear() { bits_ = 0; }29 void setAll() { bits_ = ~(basic_int_t)0; }30 bool empty() const { return bits_ == 0; }31 32 // Returns true if the bit has changed from 0 to 1.33 bool setBit(uptr idx) {34 basic_int_t old = bits_;35 bits_ |= mask(idx);36 return bits_ != old;37 }38 39 // Returns true if the bit has changed from 1 to 0.40 bool clearBit(uptr idx) {41 basic_int_t old = bits_;42 bits_ &= ~mask(idx);43 return bits_ != old;44 }45 46 bool getBit(uptr idx) const { return (bits_ & mask(idx)) != 0; }47 48 uptr getAndClearFirstOne() {49 CHECK(!empty());50 uptr idx = LeastSignificantSetBitIndex(bits_);51 clearBit(idx);52 return idx;53 }54 55 // Do "this |= v" and return whether new bits have been added.56 bool setUnion(const BasicBitVector &v) {57 basic_int_t old = bits_;58 bits_ |= v.bits_;59 return bits_ != old;60 }61 62 // Do "this &= v" and return whether any bits have been removed.63 bool setIntersection(const BasicBitVector &v) {64 basic_int_t old = bits_;65 bits_ &= v.bits_;66 return bits_ != old;67 }68 69 // Do "this &= ~v" and return whether any bits have been removed.70 bool setDifference(const BasicBitVector &v) {71 basic_int_t old = bits_;72 bits_ &= ~v.bits_;73 return bits_ != old;74 }75 76 void copyFrom(const BasicBitVector &v) { bits_ = v.bits_; }77 78 // Returns true if 'this' intersects with 'v'.79 bool intersectsWith(const BasicBitVector &v) const {80 return (bits_ & v.bits_) != 0;81 }82 83 // for (BasicBitVector<>::Iterator it(bv); it.hasNext();) {84 // uptr idx = it.next();85 // use(idx);86 // }87 class Iterator {88 public:89 Iterator() { }90 explicit Iterator(const BasicBitVector &bv) : bv_(bv) {}91 bool hasNext() const { return !bv_.empty(); }92 uptr next() { return bv_.getAndClearFirstOne(); }93 void clear() { bv_.clear(); }94 private:95 BasicBitVector bv_;96 };97 98 private:99 basic_int_t mask(uptr idx) const {100 CHECK_LT(idx, size());101 return (basic_int_t)1UL << idx;102 }103 basic_int_t bits_;104};105 106// Fixed size bit vector of (kLevel1Size*BV::kSize**2) bits.107// The implementation is optimized for better performance on108// sparse bit vectors, i.e. the those with few set bits.109template <uptr kLevel1Size = 1, class BV = BasicBitVector<> >110class TwoLevelBitVector {111 // This is essentially a 2-level bit vector.112 // Set bit in the first level BV indicates that there are set bits113 // in the corresponding BV of the second level.114 // This structure allows O(kLevel1Size) time for clear() and empty(),115 // as well fast handling of sparse BVs.116 public:117 enum SizeEnum : uptr { kSize = BV::kSize * BV::kSize * kLevel1Size };118 // No CTOR.119 120 uptr size() const { return kSize; }121 122 void clear() {123 for (uptr i = 0; i < kLevel1Size; i++)124 l1_[i].clear();125 }126 127 void setAll() {128 for (uptr i0 = 0; i0 < kLevel1Size; i0++) {129 l1_[i0].setAll();130 for (uptr i1 = 0; i1 < BV::kSize; i1++)131 l2_[i0][i1].setAll();132 }133 }134 135 bool empty() const {136 for (uptr i = 0; i < kLevel1Size; i++)137 if (!l1_[i].empty())138 return false;139 return true;140 }141 142 // Returns true if the bit has changed from 0 to 1.143 bool setBit(uptr idx) {144 check(idx);145 uptr i0 = idx0(idx);146 uptr i1 = idx1(idx);147 uptr i2 = idx2(idx);148 if (!l1_[i0].getBit(i1)) {149 l1_[i0].setBit(i1);150 l2_[i0][i1].clear();151 }152 bool res = l2_[i0][i1].setBit(i2);153 // Printf("%s: %zd => %zd %zd %zd; %d\n", __func__,154 // idx, i0, i1, i2, res);155 return res;156 }157 158 bool clearBit(uptr idx) {159 check(idx);160 uptr i0 = idx0(idx);161 uptr i1 = idx1(idx);162 uptr i2 = idx2(idx);163 bool res = false;164 if (l1_[i0].getBit(i1)) {165 res = l2_[i0][i1].clearBit(i2);166 if (l2_[i0][i1].empty())167 l1_[i0].clearBit(i1);168 }169 return res;170 }171 172 bool getBit(uptr idx) const {173 check(idx);174 uptr i0 = idx0(idx);175 uptr i1 = idx1(idx);176 uptr i2 = idx2(idx);177 // Printf("%s: %zd => %zd %zd %zd\n", __func__, idx, i0, i1, i2);178 return l1_[i0].getBit(i1) && l2_[i0][i1].getBit(i2);179 }180 181 uptr getAndClearFirstOne() {182 for (uptr i0 = 0; i0 < kLevel1Size; i0++) {183 if (l1_[i0].empty()) continue;184 uptr i1 = l1_[i0].getAndClearFirstOne();185 uptr i2 = l2_[i0][i1].getAndClearFirstOne();186 if (!l2_[i0][i1].empty())187 l1_[i0].setBit(i1);188 uptr res = i0 * BV::kSize * BV::kSize + i1 * BV::kSize + i2;189 // Printf("getAndClearFirstOne: %zd %zd %zd => %zd\n", i0, i1, i2, res);190 return res;191 }192 CHECK(0);193 return 0;194 }195 196 // Do "this |= v" and return whether new bits have been added.197 bool setUnion(const TwoLevelBitVector &v) {198 bool res = false;199 for (uptr i0 = 0; i0 < kLevel1Size; i0++) {200 BV t = v.l1_[i0];201 while (!t.empty()) {202 uptr i1 = t.getAndClearFirstOne();203 if (l1_[i0].setBit(i1))204 l2_[i0][i1].clear();205 if (l2_[i0][i1].setUnion(v.l2_[i0][i1]))206 res = true;207 }208 }209 return res;210 }211 212 // Do "this &= v" and return whether any bits have been removed.213 bool setIntersection(const TwoLevelBitVector &v) {214 bool res = false;215 for (uptr i0 = 0; i0 < kLevel1Size; i0++) {216 if (l1_[i0].setIntersection(v.l1_[i0]))217 res = true;218 if (!l1_[i0].empty()) {219 BV t = l1_[i0];220 while (!t.empty()) {221 uptr i1 = t.getAndClearFirstOne();222 if (l2_[i0][i1].setIntersection(v.l2_[i0][i1]))223 res = true;224 if (l2_[i0][i1].empty())225 l1_[i0].clearBit(i1);226 }227 }228 }229 return res;230 }231 232 // Do "this &= ~v" and return whether any bits have been removed.233 bool setDifference(const TwoLevelBitVector &v) {234 bool res = false;235 for (uptr i0 = 0; i0 < kLevel1Size; i0++) {236 BV t = l1_[i0];237 t.setIntersection(v.l1_[i0]);238 while (!t.empty()) {239 uptr i1 = t.getAndClearFirstOne();240 if (l2_[i0][i1].setDifference(v.l2_[i0][i1]))241 res = true;242 if (l2_[i0][i1].empty())243 l1_[i0].clearBit(i1);244 }245 }246 return res;247 }248 249 void copyFrom(const TwoLevelBitVector &v) {250 clear();251 setUnion(v);252 }253 254 // Returns true if 'this' intersects with 'v'.255 bool intersectsWith(const TwoLevelBitVector &v) const {256 for (uptr i0 = 0; i0 < kLevel1Size; i0++) {257 BV t = l1_[i0];258 t.setIntersection(v.l1_[i0]);259 while (!t.empty()) {260 uptr i1 = t.getAndClearFirstOne();261 if (!v.l1_[i0].getBit(i1)) continue;262 if (l2_[i0][i1].intersectsWith(v.l2_[i0][i1]))263 return true;264 }265 }266 return false;267 }268 269 // for (TwoLevelBitVector<>::Iterator it(bv); it.hasNext();) {270 // uptr idx = it.next();271 // use(idx);272 // }273 class Iterator {274 public:275 Iterator() { }276 explicit Iterator(const TwoLevelBitVector &bv) : bv_(bv), i0_(0), i1_(0) {277 it1_.clear();278 it2_.clear();279 }280 281 bool hasNext() const {282 if (it1_.hasNext()) return true;283 for (uptr i = i0_; i < kLevel1Size; i++)284 if (!bv_.l1_[i].empty()) return true;285 return false;286 }287 288 uptr next() {289 // Printf("++++: %zd %zd; %d %d; size %zd\n", i0_, i1_, it1_.hasNext(),290 // it2_.hasNext(), kSize);291 if (!it1_.hasNext() && !it2_.hasNext()) {292 for (; i0_ < kLevel1Size; i0_++) {293 if (bv_.l1_[i0_].empty()) continue;294 it1_ = typename BV::Iterator(bv_.l1_[i0_]);295 // Printf("+i0: %zd %zd; %d %d; size %zd\n", i0_, i1_, it1_.hasNext(),296 // it2_.hasNext(), kSize);297 break;298 }299 }300 if (!it2_.hasNext()) {301 CHECK(it1_.hasNext());302 i1_ = it1_.next();303 it2_ = typename BV::Iterator(bv_.l2_[i0_][i1_]);304 // Printf("++i1: %zd %zd; %d %d; size %zd\n", i0_, i1_, it1_.hasNext(),305 // it2_.hasNext(), kSize);306 }307 CHECK(it2_.hasNext());308 uptr i2 = it2_.next();309 uptr res = i0_ * BV::kSize * BV::kSize + i1_ * BV::kSize + i2;310 // Printf("+ret: %zd %zd; %d %d; size %zd; res: %zd\n", i0_, i1_,311 // it1_.hasNext(), it2_.hasNext(), kSize, res);312 if (!it1_.hasNext() && !it2_.hasNext())313 i0_++;314 return res;315 }316 317 private:318 const TwoLevelBitVector &bv_;319 uptr i0_, i1_;320 typename BV::Iterator it1_, it2_;321 };322 323 private:324 void check(uptr idx) const { CHECK_LT(idx, size()); }325 326 uptr idx0(uptr idx) const {327 uptr res = idx / (BV::kSize * BV::kSize);328 CHECK_LT(res, kLevel1Size);329 return res;330 }331 332 uptr idx1(uptr idx) const {333 uptr res = (idx / BV::kSize) % BV::kSize;334 CHECK_LT(res, BV::kSize);335 return res;336 }337 338 uptr idx2(uptr idx) const {339 uptr res = idx % BV::kSize;340 CHECK_LT(res, BV::kSize);341 return res;342 }343 344 BV l1_[kLevel1Size];345 BV l2_[kLevel1Size][BV::kSize];346};347 348} // namespace __sanitizer349 350#endif // SANITIZER_BITVECTOR_H351