compiler-rt/test/fuzzer/RepeatedBytesTest.cpp

   1 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   2 // See https://llvm.org/LICENSE.txt for license information.
   3 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   4
   5 // Simple test for a fuzzer. The fuzzer must find repeated bytes.
   6 #include <assert.h>
   7 #include <cstddef>
   8 #include <cstdint>
   9 #include <cstdlib>
  10 #include <iostream>
  11 #include <ostream>
  12
  13 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
  14   assert(Data);
  15   // Looking for AAAAAAAAAAAAAAAAAAAAAA or some such.
  16   size_t CurA = 0, MaxA = 0;
  17   for (size_t i = 0; i < Size; i++) {
  18     // Make sure there are no conditionals in the loop so that
  19     // coverage can't help the fuzzer.
  20     int EQ = Data[i] == 'A';
  21     CurA = EQ * (CurA + 1);
  22     int GT = CurA > MaxA;
  23     MaxA = GT * CurA + (!GT) * MaxA;
  24   }
  25   if (MaxA >= 20) {
  26     std::cout << "BINGO; Found the target (Max: " << MaxA << "), exiting\n"
  27               << std::flush;
  28     exit(0);
  29   }
  30   return 0;
  31 }
  32