text: // RUN: %clang_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
  // UNSUPPORTED: tvos, watchos
  // XFAIL: ios && !iossim
  #include "sanitizer_common/sanitizer_ucontext.h"
  #include "test.h"
  
  char stack[64 * 1024] __attribute__((aligned(16)));
  
  ucontext_t uc, orig_uc1, orig_uc2;
  void *fiber, *orig_fiber1, *orig_fiber2;
  
  int var;
  
  void *Thread(void *x) {
    orig_fiber2 = __tsan_get_current_fiber();
    swapcontext(&orig_uc2, &orig_uc1);
    return 0;
  }
  
  void func() {
    pthread_t t;
    pthread_create(&t, 0, Thread, 0);
    pthread_join(t, 0);
    __tsan_switch_to_fiber(orig_fiber1, 0);
    swapcontext(&uc, &orig_uc1);
  }
  
  int main() {
    orig_fiber1 = __tsan_get_current_fiber();
    fiber = __tsan_create_fiber(0);
    getcontext(&uc);
    uc.uc_stack.ss_sp = stack;
    uc.uc_stack.ss_size = sizeof(stack);
    uc.uc_link = 0;
    makecontext(&uc, func, 0);
    var = 1;
    __tsan_switch_to_fiber(fiber, 0);
    swapcontext(&orig_uc1, &uc);
    var = 2;
    __tsan_switch_to_fiber(orig_fiber2, 0);
    swapcontext(&orig_uc1, &orig_uc2);
    var = 3;
    __tsan_destroy_fiber(fiber);
    fprintf(stderr, "PASS\n");
    return 0;
  }
  
  // CHECK-NOT: WARNING: ThreadSanitizer:
  // CHECK: PASS
  