third_party/llvm-project/compiler-rt/test/tsan/Darwin/deadlock.mm

// RUN: %clang_tsan %s -o %t -framework Foundation
// RUN: %deflake %run %t 2>&1 | FileCheck %s

#import <Foundation/Foundation.h>

#import "../test.h"

pthread_mutex_t m1;
pthread_mutex_t m2;

int main(int argc, const char *argv[]) {
  barrier_init(&barrier, 2);
  fprintf(stderr, "Hello world.\n");

  pthread_mutex_init(&m1, NULL);
  pthread_mutex_init(&m2, NULL);
  
  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    pthread_mutex_lock(&m1);
    pthread_mutex_lock(&m2);
    pthread_mutex_unlock(&m2);
    pthread_mutex_unlock(&m1);

    barrier_wait(&barrier);
  });
  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    barrier_wait(&barrier);

    pthread_mutex_lock(&m2);
    pthread_mutex_lock(&m1);
    pthread_mutex_unlock(&m1);
    pthread_mutex_unlock(&m2);

    dispatch_sync(dispatch_get_main_queue(), ^{
      CFRunLoopStop(CFRunLoopGetCurrent());
    });
  });

  CFRunLoopRun();
  
  fprintf(stderr, "Done.\n");
  return 0;
}

// CHECK: Hello world.
// CHECK: WARNING: ThreadSanitizer: lock-order-inversion (potential deadlock)
// CHECK: Done.