1 // RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
2 #include "test.h"
3 
4 /*
5 Annotations usage example.
6 
7 Tsan does not see synchronization in barrier_wait.
8 ANNOTATE_HAPPENS_BEFORE/AFTER communicate the synchronization to tsan
9 and prevent the race report.
10 */
11 
12 int Global;
13 
14 void *Thread1(void *x) {
15   barrier_wait(&barrier);
16   ANNOTATE_HAPPENS_AFTER(&barrier);
17   Global++;
18   return NULL;
19 }
20 
21 void *Thread2(void *x) {
22   Global--;
23   ANNOTATE_HAPPENS_BEFORE(&barrier);
24   barrier_wait(&barrier);
25   return NULL;
26 }
27 
28 int main() {
29   barrier_init(&barrier, 2);
30   pthread_t t[2];
31   pthread_create(&t[0], NULL, Thread1, NULL);
32   pthread_create(&t[1], NULL, Thread2, NULL);
33   pthread_join(t[0], NULL);
34   pthread_join(t[1], NULL);
35   fprintf(stderr, "DONE\n");
36   return 0;
37 }
38 
39 // CHECK-NOT: WARNING: ThreadSanitizer: data race
40 // CHECK: DONE
41 
42