compiler-rt/test/fuzzer/ThreeFunctionsTest.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 // Find "FUZZME", the target has 3 different functions.
   6 //
   7 // This test, and the accompanying lit tests
   8 // (dataflow.test, only-some-bytes.test) assume that the compiler
   9 // instruments functions in their lexical order.
  10 // This assumption is not guaranteed, but it is likely to hold.
  11 // It allows to simplify the test quite a bit: in the lit tests
  12 // LLVMFuzzerTestOneInput is "F0", Func1 is "F1", Func2 is "F2".
  13 #include <assert.h>
  14 #include <cstddef>
  15 #include <cstdint>
  16 #include <cstdlib>
  17 #include <cstdio>
  18
  19 extern "C" bool Func1(const uint8_t *Data, size_t Size);
  20 extern "C" bool Func2(const uint8_t *Data, size_t Size);
  21
  22 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
  23   if (Size >= 5
  24       && Data[0] == 'F'
  25       && Data[1] == 'U'
  26       && Data[2] == 'Z'
  27       && Data[3] == 'Z'
  28       && Func1(Data, Size)
  29       && Func2(Data, Size)) {
  30         fprintf(stderr, "BINGO\n");
  31         abort();
  32   }
  33   return 0;
  34 }
  35
  36 extern "C"
  37 __attribute__((noinline))
  38 bool Func1(const uint8_t *Data, size_t Size) {
  39   // assumes Size >= 5, doesn't check it.
  40   return Data[4] == 'M';
  41 }
  42
  43 extern "C"
  44 __attribute__((noinline))
  45 bool Func2(const uint8_t *Data, size_t Size) {
  46   return Size >= 6 && Data[5] == 'E';
  47 }
  48
  49