1326943Sdim//===- FuzzerValueBitMap.h - INTERNAL - Bit map -----------------*- C++ -* ===//
2326943Sdim//
3353358Sdim// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4353358Sdim// See https://llvm.org/LICENSE.txt for license information.
5353358Sdim// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6326943Sdim//
7326943Sdim//===----------------------------------------------------------------------===//
8326943Sdim// ValueBitMap.
9326943Sdim//===----------------------------------------------------------------------===//
10326943Sdim
11326943Sdim#ifndef LLVM_FUZZER_VALUE_BIT_MAP_H
12326943Sdim#define LLVM_FUZZER_VALUE_BIT_MAP_H
13326943Sdim
14326943Sdim#include "FuzzerDefs.h"
15326943Sdim
16326943Sdimnamespace fuzzer {
17326943Sdim
18326943Sdim// A bit map containing kMapSizeInWords bits.
19326943Sdimstruct ValueBitMap {
20326943Sdim  static const size_t kMapSizeInBits = 1 << 16;
21326943Sdim  static const size_t kMapPrimeMod = 65371;  // Largest Prime < kMapSizeInBits;
22326943Sdim  static const size_t kBitsInWord = (sizeof(uintptr_t) * 8);
23326943Sdim  static const size_t kMapSizeInWords = kMapSizeInBits / kBitsInWord;
24326943Sdim public:
25326943Sdim
26326943Sdim  // Clears all bits.
27326943Sdim  void Reset() { memset(Map, 0, sizeof(Map)); }
28326943Sdim
29326943Sdim  // Computes a hash function of Value and sets the corresponding bit.
30326943Sdim  // Returns true if the bit was changed from 0 to 1.
31326943Sdim  ATTRIBUTE_NO_SANITIZE_ALL
32326943Sdim  inline bool AddValue(uintptr_t Value) {
33326943Sdim    uintptr_t Idx = Value % kMapSizeInBits;
34326943Sdim    uintptr_t WordIdx = Idx / kBitsInWord;
35326943Sdim    uintptr_t BitIdx = Idx % kBitsInWord;
36326943Sdim    uintptr_t Old = Map[WordIdx];
37353358Sdim    uintptr_t New = Old | (1ULL << BitIdx);
38326943Sdim    Map[WordIdx] = New;
39326943Sdim    return New != Old;
40326943Sdim  }
41326943Sdim
42326943Sdim  ATTRIBUTE_NO_SANITIZE_ALL
43326943Sdim  inline bool AddValueModPrime(uintptr_t Value) {
44326943Sdim    return AddValue(Value % kMapPrimeMod);
45326943Sdim  }
46326943Sdim
47326943Sdim  inline bool Get(uintptr_t Idx) {
48326943Sdim    assert(Idx < kMapSizeInBits);
49326943Sdim    uintptr_t WordIdx = Idx / kBitsInWord;
50326943Sdim    uintptr_t BitIdx = Idx % kBitsInWord;
51353358Sdim    return Map[WordIdx] & (1ULL << BitIdx);
52326943Sdim  }
53326943Sdim
54326943Sdim  size_t SizeInBits() const { return kMapSizeInBits; }
55326943Sdim
56326943Sdim  template <class Callback>
57326943Sdim  ATTRIBUTE_NO_SANITIZE_ALL
58326943Sdim  void ForEach(Callback CB) const {
59326943Sdim    for (size_t i = 0; i < kMapSizeInWords; i++)
60326943Sdim      if (uintptr_t M = Map[i])
61326943Sdim        for (size_t j = 0; j < sizeof(M) * 8; j++)
62326943Sdim          if (M & ((uintptr_t)1 << j))
63326943Sdim            CB(i * sizeof(M) * 8 + j);
64326943Sdim  }
65326943Sdim
66326943Sdim private:
67353358Sdim  ATTRIBUTE_ALIGNED(512) uintptr_t Map[kMapSizeInWords];
68326943Sdim};
69326943Sdim
70326943Sdim}  // namespace fuzzer
71326943Sdim
72326943Sdim#endif  // LLVM_FUZZER_VALUE_BIT_MAP_H
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