60 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			60 lines
		
	
	
		
			1.8 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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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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  // Clears all bits.
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  void Reset() { memset(Map, 0, sizeof(Map)); }
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  // Computed a hash function of Value and sets the corresponding bit.
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  inline void 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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    Map[WordIdx] |= 1UL << BitIdx;
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  }
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  // Merges 'Other' into 'this', clears 'Other',
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  // returns the number of set bits in 'this'.
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  ATTRIBUTE_TARGET_POPCNT
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  size_t MergeFrom(ValueBitMap &Other) {
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    uintptr_t Res = 0;
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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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    return Res;
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  }
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 private:
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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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