1//===- FuzzerValueBitMap.h - INTERNAL - Bit map -----------------*- 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-exception
6//
7//===----------------------------------------------------------------------===//
8// ValueBitMap.
9//===----------------------------------------------------------------------===//
10
11#ifndef LLVM_FUZZER_VALUE_BIT_MAP_H
12#define LLVM_FUZZER_VALUE_BIT_MAP_H
13
14#include "FuzzerDefs.h"
15
16namespace fuzzer {
17
18// A bit map containing kMapSizeInWords bits.
19struct ValueBitMap {
20  static const size_t kMapSizeInBits = 1 << 16;
21  static const size_t kMapPrimeMod = 65371;  // Largest Prime < kMapSizeInBits;
22  static const size_t kBitsInWord = (sizeof(uintptr_t) * 8);
23  static const size_t kMapSizeInWords = kMapSizeInBits / kBitsInWord;
24 public:
25
26  // Clears all bits.
27  void Reset() { memset(Map, 0, sizeof(Map)); }
28
29  // Computes a hash function of Value and sets the corresponding bit.
30  // Returns true if the bit was changed from 0 to 1.
31  ATTRIBUTE_NO_SANITIZE_ALL
32  inline bool AddValue(uintptr_t Value) {
33    uintptr_t Idx = Value % kMapSizeInBits;
34    uintptr_t WordIdx = Idx / kBitsInWord;
35    uintptr_t BitIdx = Idx % kBitsInWord;
36    uintptr_t Old = Map[WordIdx];
37    uintptr_t New = Old | (1ULL << BitIdx);
38    Map[WordIdx] = New;
39    return New != Old;
40  }
41
42  ATTRIBUTE_NO_SANITIZE_ALL
43  inline bool AddValueModPrime(uintptr_t Value) {
44    return AddValue(Value % kMapPrimeMod);
45  }
46
47  inline bool Get(uintptr_t Idx) {
48    assert(Idx < kMapSizeInBits);
49    uintptr_t WordIdx = Idx / kBitsInWord;
50    uintptr_t BitIdx = Idx % kBitsInWord;
51    return Map[WordIdx] & (1ULL << BitIdx);
52  }
53
54  size_t SizeInBits() const { return kMapSizeInBits; }
55
56  template <class Callback>
57  ATTRIBUTE_NO_SANITIZE_ALL
58  void ForEach(Callback CB) const {
59    for (size_t i = 0; i < kMapSizeInWords; i++)
60      if (uintptr_t M = Map[i])
61        for (size_t j = 0; j < sizeof(M) * 8; j++)
62          if (M & ((uintptr_t)1 << j))
63            CB(i * sizeof(M) * 8 + j);
64  }
65
66 private:
67  ATTRIBUTE_ALIGNED(512) uintptr_t Map[kMapSizeInWords];
68};
69
70}  // namespace fuzzer
71
72#endif  // LLVM_FUZZER_VALUE_BIT_MAP_H
73