1/* Copyright JS Foundation and other contributors, http://js.foundation
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16/*
17 * This source contains libc overrides for the sake of stable benchmarking. If
18 * building a binary for the purpose of benchmarking, the object compiled from
19 * this source is to be injected into the list of objects-to-be-linked before
20 * the list of libraries-to-be-linked to ensure that the linker picks up these
21 * implementations.
22 */
23
24#ifdef __GNUC__
25/*
26 * Note:
27 *      This is nasty and dangerous. However, we only need the timeval structure
28 *      from sys/time.h. Unfortunately, the same header also declares
29 *      gettimeofday, which has different declarations on different platforms
30 *      (e.g., macOS, Linux). So, instead of #ifdef'ing for platforms, we simply
31 *      tweak the header to declare another function. Don't try this at home.
32 */
33#define gettimeofday __prevent_conflicting_gettimeofday_declarations__
34#include <sys/time.h>
35#undef gettimeofday
36
37int gettimeofday (struct timeval *, void *);
38
39/**
40 * Useless but stable gettimeofday implementation. Returns Epoch. Ensures that
41 * test cases relying on "now" yield stable results.
42 */
43int gettimeofday (struct timeval *tv,
44                  void *tz)
45{
46  (void) tz;
47  tv->tv_sec = 0;
48  tv->tv_usec = 0;
49  return 0;
50} /* gettimeofday */
51#endif /* __GNUC__ */
52
53int rand (void);
54
55/**
56 * Useless but stable rand implementation. Returns 4. Ensures that test cases
57 * relying on randomness yield stable results.
58 */
59int rand (void)
60{
61  return 4; /* Chosen by fair dice roll. Guaranteed to be random. */
62} /* rand */
63