1// RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
2#include "test.h"
3
4/*
5Annotations usage example.
6
7Tsan does not see synchronization in barrier_wait.
8ANNOTATE_HAPPENS_BEFORE/AFTER communicate the synchronization to tsan
9and prevent the race report.
10
11If the compiler does not support __has_feature macro, then you can build with
12CFLAGS="-fsanitize=thread -DTHREAD_SANITIZER" and then use
13#ifdef THREAD_SANITIZER to enabled annotations.
14*/
15
16#if defined(__has_feature) && __has_feature(thread_sanitizer)
17# define ANNOTATE_HAPPENS_BEFORE(addr) \
18 AnnotateHappensBefore(__FILE__, __LINE__, (void*)(addr))
19# define ANNOTATE_HAPPENS_AFTER(addr) \
20 AnnotateHappensAfter(__FILE__, __LINE__, (void*)(addr))
21extern "C" void AnnotateHappensBefore(const char *f, int l, void *addr);
22extern "C" void AnnotateHappensAfter(const char *f, int l, void *addr);
23#else
24# define ANNOTATE_HAPPENS_BEFORE(addr)
25# define ANNOTATE_HAPPENS_AFTER(addr)
26#endif
27
28int Global;
29
30void *Thread1(void *x) {
31 barrier_wait(&barrier);
32 ANNOTATE_HAPPENS_AFTER(&barrier);
33 Global++;
34 return NULL;
35}
36
37void *Thread2(void *x) {
38 Global--;
39 ANNOTATE_HAPPENS_BEFORE(&barrier);
40 barrier_wait(&barrier);
41 return NULL;
42}
43
44int main() {
45 barrier_init(&barrier, 2);
46 pthread_t t[2];
47 pthread_create(&t[0], NULL, Thread1, NULL);
48 pthread_create(&t[1], NULL, Thread2, NULL);
49 pthread_join(t[0], NULL);
50 pthread_join(t[1], NULL);
51 fprintf(stderr, "DONE\n");
52 return 0;
53}
54
55// CHECK-NOT: WARNING: ThreadSanitizer: data race
56// CHECK: DONE
57
58