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 17 namespace fuzzer { 18 19 // A bit map containing kMapSizeInWords bits. 20 struct 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. ResetValueBitMap28 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 AddValueValueBitMap33 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 AddValueModPrimeValueBitMap44 inline bool AddValueModPrime(uintptr_t Value) { 45 return AddValue(Value % kMapPrimeMod); 46 } 47 GetValueBitMap48 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 SizeInBitsValueBitMap55 size_t SizeInBits() const { return kMapSizeInBits; } 56 57 template <class Callback> 58 ATTRIBUTE_NO_SANITIZE_ALL ForEachValueBitMap59 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