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 "FuzzerPlatform.h"
15#include <cstdint>
16
17namespace fuzzer {
18
19// A bit map containing kMapSizeInWords bits.
20struct ValueBitMap {
21  static const size_t kMapSizeInBits = 1 << 16;
22  static const size_t kMapPrimeMod = 65371;  // Largest Prime < kMapSizeInBits;
23  static const size_t kBitsInWord = (sizeof(uintptr_t) * 8);
24  static const size_t kMapSizeInWords = kMapSizeInBits / kBitsInWord;
25 public:
26
27  // Clears all bits.
28  void Reset() { memset(Map, 0, sizeof(Map)); }
29
30  // Computes a hash function of Value and sets the corresponding bit.
31  // Returns true if the bit was changed from 0 to 1.
32  ATTRIBUTE_NO_SANITIZE_ALL
33  inline bool AddValue(uintptr_t Value) {
34    uintptr_t Idx = Value % kMapSizeInBits;
35    uintptr_t WordIdx = Idx / kBitsInWord;
36    uintptr_t BitIdx = Idx % kBitsInWord;
37    uintptr_t Old = Map[WordIdx];
38    uintptr_t New = Old | (1ULL << BitIdx);
39    Map[WordIdx] = New;
40    return New != Old;
41  }
42
43  ATTRIBUTE_NO_SANITIZE_ALL
44  inline bool AddValueModPrime(uintptr_t Value) {
45    return AddValue(Value % kMapPrimeMod);
46  }
47
48  inline bool Get(uintptr_t Idx) {
49    assert(Idx < kMapSizeInBits);
50    uintptr_t WordIdx = Idx / kBitsInWord;
51    uintptr_t BitIdx = Idx % kBitsInWord;
52    return Map[WordIdx] & (1ULL << BitIdx);
53  }
54
55  size_t SizeInBits() const { return kMapSizeInBits; }
56
57  template <class Callback>
58  ATTRIBUTE_NO_SANITIZE_ALL
59  void ForEach(Callback CB) const {
60    for (size_t i = 0; i < kMapSizeInWords; i++)
61      if (uintptr_t M = Map[i])
62        for (size_t j = 0; j < sizeof(M) * 8; j++)
63          if (M & ((uintptr_t)1 << j))
64            CB(i * sizeof(M) * 8 + j);
65  }
66
67 private:
68  ATTRIBUTE_ALIGNED(512) uintptr_t Map[kMapSizeInWords];
69};
70
71}  // namespace fuzzer
72
73#endif  // LLVM_FUZZER_VALUE_BIT_MAP_H
74