compiler-rt/test/fuzzer/CallerCalleeTest.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.
   6 // Try to find the target using the indirect caller-callee pairs.
   7 #include <cstddef>
   8 #include <cstdint>
   9 #include <cstdlib>
  10 #include <cstring>
  11 #include <iostream>
  12
  13 typedef void (*F)();
  14 static F t[256];
  15
  16 void f34() {
  17   std::cerr << "BINGO\n";
  18   exit(1);
  19 }
  20 void f23() { t[(unsigned)'d'] = f34;}
  21 void f12() { t[(unsigned)'c'] = f23;}
  22 void f01() { t[(unsigned)'b'] = f12;}
  23 void f00() {}
  24
  25 static F t0[256] = {
  26   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  27   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  28   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  29   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  30   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  31   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  32   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  33   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  34   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  35   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  36   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  37   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  38   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  39   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  40   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  41   f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
  42 };
  43
  44 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
  45   if (Size < 4) return 0;
  46   // Spoof the counters.
  47   for (int i = 0; i < 200; i++) {
  48     f23();
  49     f12();
  50     f01();
  51   }
  52   memcpy(t, t0, sizeof(t));
  53   t[(unsigned)'a'] = f01;
  54   t[Data[0]]();
  55   t[Data[1]]();
  56   t[Data[2]]();
  57   t[Data[3]]();
  58   return 0;
  59 }
  60