compiler-rt/test/tsan/write_in_reader_lock.cpp

   1 // RUN: %clangxx_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
   2 #include "test.h"
   3
   4 pthread_rwlock_t rwlock;
   5 int GLOB;
   6
   7 void *Thread1(void *p) {
   8   (void)p;
   9   pthread_rwlock_rdlock(&rwlock);
  10   barrier_wait(&barrier);
  11   // Write under reader lock.
  12   GLOB++;
  13   pthread_rwlock_unlock(&rwlock);
  14   return 0;
  15 }
  16
  17 int main(int argc, char *argv[]) {
  18   barrier_init(&barrier, 2);
  19   pthread_rwlock_init(&rwlock, NULL);
  20   pthread_rwlock_rdlock(&rwlock);
  21   pthread_t t;
  22   pthread_create(&t, 0, Thread1, 0);
  23   volatile int x = GLOB;
  24   (void)x;
  25   pthread_rwlock_unlock(&rwlock);
  26   barrier_wait(&barrier);
  27   pthread_join(t, 0);
  28   pthread_rwlock_destroy(&rwlock);
  29   return 0;
  30 }
  31
  32 // CHECK: WARNING: ThreadSanitizer: data race
  33 // CHECK:   Write of size 4 at {{.*}} by thread T1{{.*}}:
  34 // CHECK:     #0 Thread1(void*) {{.*}}write_in_reader_lock.cpp:12
  35 // CHECK:   Previous read of size 4 at {{.*}} by main thread{{.*}}:
  36 // CHECK:     #0 main {{.*}}write_in_reader_lock.cpp:23