#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <dlfcn.h>
#include <stddef.h>

// TSan-invisible barrier.
// Tests use it to establish necessary execution order in a way that does not
// interfere with tsan (does not establish synchronization between threads).
__typeof(pthread_barrier_wait) *barrier_wait;

void barrier_init(pthread_barrier_t *barrier, unsigned count) {
  if (barrier_wait == 0) {
    void *h = dlopen("libpthread.so.0", RTLD_LAZY);
    if (h == 0) {
      fprintf(stderr, "failed to dlopen libpthread.so.0, exiting\n");
      exit(1);
    }
    barrier_wait = (__typeof(barrier_wait))dlsym(h, "pthread_barrier_wait");
    if (barrier_wait == 0) {
      fprintf(stderr, "failed to resolve pthread_barrier_wait, exiting\n");
      exit(1);
    }
  }
  pthread_barrier_init(barrier, 0, count);
}

// Default instance of the barrier, but a test can declare more manually.
pthread_barrier_t barrier;