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 ABCxxFxUxZxxx... (2048+ bytes, 'x' is any byte)
6#include <assert.h>
7#include <cstddef>
8#include <cstdint>
9#include <cstdlib>
10#include <cstring>
11#include <cstdio>
12
13const size_t N = 2048;
14typedef const uint8_t *IN;
15
16static volatile int one = 1;
17
18__attribute__((noinline)) void bad() {
19 fprintf(stderr, format: "BINGO\n");
20 if (one)
21 abort();
22}
23
24extern "C"
25__attribute__((noinline)) void f0(IN in) {
26 uint32_t x = in[5] + 251 * in[7] + 251 * 251 * in[9];
27 if (x == 'F' + 251 * 'U' + 251 * 251 * 'Z') {
28 // artificially inflate uncovered control in f0
29 // so that auto-focus is more likely to chose this function.
30 if (one == -1) {
31 if (one == 2) one = 1; if (one == 3) one = 1; if (one == 4) one = 1;
32 if (one == 5) one = 1; if (one == 6) one = 1; if (one == 7) one = 1;
33 if (one == 8) one = 1; if (one == 9) one = 1; if (one == 0) one = 1;
34 }
35 bad();
36 }
37}
38
39__attribute__((noinline)) void fD(IN in) { f0(in); }
40__attribute__((noinline)) void fC(IN in) { if (in[2] == 'C') fD(in); }
41__attribute__((noinline)) void fB(IN in) { if (in[1] == 'B') fC(in); }
42__attribute__((noinline)) void fA(IN in) { if (in[0] == 'A') fB(in); }
43
44extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
45 if (Size < N) return 0;
46 fA(in: (IN)Data);
47 return 0;
48}
49

source code of compiler-rt/test/fuzzer/OnlySomeBytesTest.cpp