Freeze/thaw at safepoint stub?

[Aleksey Shipilev]

Hi,

I see the code that allows freeze/thaw from safepoint stub, in addition for "normal" yield stub. But 
I also suspect that code is effectively dead? That is:

  - FreezeBase::_preempt is always false;
  - FreezeBase::freeze_start_frame_safepoint_stub() is effectively not called;
  - FreezeBase::recurse_freeze_stub_frame() is effectively not called;
  - is_pinned0 is always called with safepoint = false;
  - ...and I suspect the thawing paths that deal with stubs are also not called?

Is this a leftover from some earlier implementation? If so, can I remove those parts to avoid 
unnecessary clutter?

-- 
Thanks,
-Aleksey