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//===- FuzzerValueBitMap.h - INTERNAL - Bit map -----------------*- C++ -* ===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// ValueBitMap.
//===----------------------------------------------------------------------===//
#ifndef LLVM_FUZZER_VALUE_BIT_MAP_H
#define LLVM_FUZZER_VALUE_BIT_MAP_H
namespace fuzzer {
// A bit map containing kMapSizeInWords bits.
struct ValueBitMap {
static const size_t kMapSizeInBits = 65371; // Prime.
static const size_t kMapSizeInBitsAligned = 65536; // 2^16
static const size_t kBitsInWord = (sizeof(uintptr_t) * 8);
static const size_t kMapSizeInWords = kMapSizeInBitsAligned / kBitsInWord;
public:
// Clears all bits.
void Reset() { memset(Map, 0, sizeof(Map)); }
// Computed a hash function of Value and sets the corresponding bit.
inline void AddValue(uintptr_t Value) {
uintptr_t Idx = Value < kMapSizeInBits ? Value : Value % kMapSizeInBits;
uintptr_t WordIdx = Idx / kBitsInWord;
uintptr_t BitIdx = Idx % kBitsInWord;
Map[WordIdx] |= 1UL << BitIdx;
}
// Merges 'Other' into 'this', clears 'Other',
// returns the number of set bits in 'this'.
ATTRIBUTE_TARGET_POPCNT
size_t MergeFrom(ValueBitMap &Other) {
uintptr_t Res = 0;
for (size_t i = 0; i < kMapSizeInWords; i++) {
auto O = Other.Map[i];
auto M = Map[i];
if (O) {
Map[i] = (M |= O);
Other.Map[i] = 0;
}
if (M)
Res += __builtin_popcountl(M);
}
return Res;
}
private:
uintptr_t Map[kMapSizeInWords] __attribute__((aligned(512)));
};
} // namespace fuzzer
#endif // LLVM_FUZZER_VALUE_BIT_MAP_H
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