Appropriate way to delete NonJavaThread objects?

[Liu, Xin]

 Hi, Hotspot developers, 

I have a question about NonJavaThread destructor. Currently, there are
some NonJavaThread subclasses. Here is a simple class hierarchy.

Thread
  NonJavaThrea
    NamedThread
      WorkerThread
      VMThread
    WatcherThread
    JfrThreadSampler
    
I found some subclasses of NonJavaThread disallow
destruction. Eg. VMThread and WatcherThread simply abort.
  // No destruction allowed
  ~VMThread() {
    guarantee(false, "VMThread deletion must fix the race with VM termination");
  }

Is it absolutely no resource leak if we skip ~Thread()? I know
Linux/FreeBSD guarantee to reclaim anything when a process is
terminated, but is it true for other platforms?

Putting aside resource leak, I don't think all NonJavaThread
subclasses necessarily have same lifecycle of JVM. Current
NonJavaThread implementation seems to inhibit from complete
destruction. eg.  JfrThreadSampler uses the following approach to
delete itself.

void JfrThreadSampler::post_run() {
  this->NonJavaThread::post_run();
  delete this;
}

I think this code is correct, but it is fragile because
NonJavaThread::post_run() nullifies Thread::clear_thread_current()
before Thread::~Thread(). "delete this" will hit the assertion of
Thread::current() at this statement. 
  // osthread() can be NULL, if creation of thread failed.
  if (osthread() != NULL) os::free_thread(osthread())


Does it matter if we ignore all destructions of NonJavaThread objects?
If the answer is no, is there an appropriate way to delete them?

Thanks,
--lx