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