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
37 int 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 */
gettimeofday(struct timeval * tv,void * tz)43 int 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
53 int rand (void);
54
55 /**
56 * Useless but stable rand implementation. Returns 4. Ensures that test cases
57 * relying on randomness yield stable results.
58 */
rand(void)59 int rand (void)
60 {
61 return 4; /* Chosen by fair dice roll. Guaranteed to be random. */
62 } /* rand */
63