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 // Test for a fuzzer. The fuzzer must find the string
6 // ABCDEFGHIJ
7 // We use it as a test for each of CrossOver functionalities
8 // by passing the following sets of two inputs to it:
9 // {ABCDE00000, ZZZZZFGHIJ}
10 // {ABCDEHIJ, ZFG} to specifically test InsertPartOf
11 // {ABCDE00HIJ, ZFG} to specifically test CopyPartOf
12 //
13 #include <assert.h>
14 #include <cstddef>
15 #include <cstdint>
16 #include <cstdlib>
17 #include <iostream>
18 #include <ostream>
19
20 static volatile int Sink;
21 static volatile int *NullPtr;
22
23 // A modified jenkins_one_at_a_time_hash initialized by non-zero,
24 // so that simple_hash(0) != 0. See also
25 // https://en.wikipedia.org/wiki/Jenkins_hash_function
simple_hash(const uint8_t * Data,size_t Size)26 static uint32_t simple_hash(const uint8_t *Data, size_t Size) {
27 uint32_t Hash = 0x12039854;
28 for (uint32_t i = 0; i < Size; i++) {
29 Hash += Data[i];
30 Hash += (Hash << 10);
31 Hash ^= (Hash >> 6);
32 }
33 Hash += (Hash << 3);
34 Hash ^= (Hash >> 11);
35 Hash += (Hash << 15);
36 return Hash;
37 }
38
39 // Don't leave the string in the binary, so that fuzzer don't cheat;
40 // const char *ABC = "ABCDEFGHIJ";
41 // static uint32_t ExpectedHash = simple_hash((const uint8_t *)ABC, 10);
42 static const uint32_t ExpectedHash = 0xe1677acb;
43
LLVMFuzzerTestOneInput(const uint8_t * Data,size_t Size)44 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
45 // fprintf(stderr, "ExpectedHash: %x\n", ExpectedHash);
46 if (Size == 10 && ExpectedHash == simple_hash(Data, Size))
47 *NullPtr = 0;
48 if (*Data == 'A')
49 Sink++;
50 if (*Data == 'Z')
51 Sink--;
52 return 0;
53 }
54