88 lines
2.6 KiB
C++
88 lines
2.6 KiB
C++
//===- FuzzerValueBitMap.h - INTERNAL - Bit map -----------------*- C++ -* ===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// ValueBitMap.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_FUZZER_VALUE_BIT_MAP_H
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#define LLVM_FUZZER_VALUE_BIT_MAP_H
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#include "FuzzerDefs.h"
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namespace fuzzer {
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// A bit map containing kMapSizeInWords bits.
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struct ValueBitMap {
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static const size_t kMapSizeInBits = 65371; // Prime.
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static const size_t kMapSizeInBitsAligned = 65536; // 2^16
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static const size_t kBitsInWord = (sizeof(uintptr_t) * 8);
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static const size_t kMapSizeInWords = kMapSizeInBitsAligned / kBitsInWord;
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public:
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static const size_t kNumberOfItems = kMapSizeInBits;
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// Clears all bits.
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void Reset() { memset(Map, 0, sizeof(Map)); }
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// Computes a hash function of Value and sets the corresponding bit.
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// Returns true if the bit was changed from 0 to 1.
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inline bool AddValue(uintptr_t Value) {
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uintptr_t Idx = Value < kMapSizeInBits ? Value : Value % kMapSizeInBits;
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uintptr_t WordIdx = Idx / kBitsInWord;
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uintptr_t BitIdx = Idx % kBitsInWord;
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uintptr_t Old = Map[WordIdx];
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uintptr_t New = Old | (1UL << BitIdx);
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Map[WordIdx] = New;
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return New != Old;
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}
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inline bool Get(uintptr_t Idx) {
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assert(Idx < kMapSizeInBits);
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uintptr_t WordIdx = Idx / kBitsInWord;
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uintptr_t BitIdx = Idx % kBitsInWord;
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return Map[WordIdx] & (1UL << BitIdx);
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}
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size_t GetNumBitsSinceLastMerge() const { return NumBits; }
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// Merges 'Other' into 'this', clears 'Other', updates NumBits,
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// returns true if new bits were added.
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ATTRIBUTE_TARGET_POPCNT
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bool MergeFrom(ValueBitMap &Other) {
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uintptr_t Res = 0;
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size_t OldNumBits = NumBits;
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for (size_t i = 0; i < kMapSizeInWords; i++) {
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auto O = Other.Map[i];
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auto M = Map[i];
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if (O) {
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Map[i] = (M |= O);
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Other.Map[i] = 0;
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}
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if (M)
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Res += __builtin_popcountl(M);
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}
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NumBits = Res;
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return OldNumBits < NumBits;
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}
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template <class Callback>
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void ForEach(Callback CB) {
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for (size_t i = 0; i < kMapSizeInWords; i++)
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if (uintptr_t M = Map[i])
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for (size_t j = 0; j < sizeof(M) * 8; j++)
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if (M & ((uintptr_t)1 << j))
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CB(i * sizeof(M) * 8 + j);
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}
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private:
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size_t NumBits = 0;
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uintptr_t Map[kMapSizeInWords] __attribute__((aligned(512)));
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};
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} // namespace fuzzer
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#endif // LLVM_FUZZER_VALUE_BIT_MAP_H
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