1 //===- FuzzerValueBitMap.h - INTERNAL - Bit map -----------------*- C++ -* ===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // ValueBitMap. 10 //===----------------------------------------------------------------------===// 11 12 #ifndef LLVM_FUZZER_VALUE_BIT_MAP_H 13 #define LLVM_FUZZER_VALUE_BIT_MAP_H 14 15 #include "FuzzerDefs.h" 16 17 namespace fuzzer { 18 19 // A bit map containing kMapSizeInWords bits. 20 struct ValueBitMap { 21 static const size_t kMapSizeInBits = 65371; // Prime. 22 static const size_t kMapSizeInBitsAligned = 65536; // 2^16 23 static const size_t kBitsInWord = (sizeof(uintptr_t) * 8); 24 static const size_t kMapSizeInWords = kMapSizeInBitsAligned / kBitsInWord; 25 public: 26 static const size_t kNumberOfItems = kMapSizeInBits; 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. AddValueValueBitMap32 inline bool AddValue(uintptr_t Value) { 33 uintptr_t Idx = Value < kMapSizeInBits ? Value : 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 | (1UL << BitIdx); 38 Map[WordIdx] = New; 39 return New != Old; 40 } 41 GetValueBitMap42 inline bool Get(uintptr_t Idx) { 43 assert(Idx < kMapSizeInBits); 44 uintptr_t WordIdx = Idx / kBitsInWord; 45 uintptr_t BitIdx = Idx % kBitsInWord; 46 return Map[WordIdx] & (1UL << BitIdx); 47 } 48 GetNumBitsSinceLastMergeValueBitMap49 size_t GetNumBitsSinceLastMerge() const { return NumBits; } 50 51 // Merges 'Other' into 'this', clears 'Other', updates NumBits, 52 // returns true if new bits were added. 53 ATTRIBUTE_TARGET_POPCNT MergeFromValueBitMap54 bool MergeFrom(ValueBitMap &Other) { 55 uintptr_t Res = 0; 56 size_t OldNumBits = NumBits; 57 for (size_t i = 0; i < kMapSizeInWords; i++) { 58 auto O = Other.Map[i]; 59 auto M = Map[i]; 60 if (O) { 61 Map[i] = (M |= O); 62 Other.Map[i] = 0; 63 } 64 if (M) 65 Res += __builtin_popcountl(M); 66 } 67 NumBits = Res; 68 return OldNumBits < NumBits; 69 } 70 71 template <class Callback> ForEachValueBitMap72 void ForEach(Callback CB) { 73 for (size_t i = 0; i < kMapSizeInWords; i++) 74 if (uintptr_t M = Map[i]) 75 for (size_t j = 0; j < sizeof(M) * 8; j++) 76 if (M & ((uintptr_t)1 << j)) 77 CB(i * sizeof(M) * 8 + j); 78 } 79 80 private: 81 size_t NumBits = 0; 82 uintptr_t Map[kMapSizeInWords] __attribute__((aligned(512))); 83 }; 84 85 } // namespace fuzzer 86 87 #endif // LLVM_FUZZER_VALUE_BIT_MAP_H 88