[PATCH] Fix "PC register is not available" issue

[Joel Brobecker]

> > it'd be interesting to understand why we send a TerminateProcess
> > first, and then try to SetThreadContext later on. It does not seem
> > to make sense.
> 
> That happens because windows_kill_inferior does this:
> 
>   static void
>   windows_kill_inferior (struct target_ops *ops)
>   {
>     CHECK (TerminateProcess (current_process_handle, 0));
> 
>     for (;;)
>       {
> 	if (!windows_continue (DBG_CONTINUE, -1, 1))
> 	  break;
> 	if (!WaitForDebugEvent (&current_event, INFINITE))
> 	  break;
> 	if (current_event.dwDebugEventCode == EXIT_PROCESS_DEBUG_EVENT)
> 	  break;
>       }
> 
>     target_mourn_inferior ();	/* Or just windows_mourn_inferior?  */
>   }
> 
> IOW, we resume the inferior (perhaps to collect all the debug
> events?).

I see - I didn't realize we were doing that, but a quick read
of the corresponding MSDN page confirms that this is necessary:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms686714(v=vs.85).aspx

> Given what I told above, what additional investigations are needed?
> 
> Note that the second part is not entirely separate: those phantom
> threads hit the problem with SetThreadContext as well, and checking
> whether the thread already exited does let through fewer of those
> warnings.

In light of everything, I have no further comment at the moment
regarding your latest patch. Perhaps one tiny detail:

> +             if (killed)
> +               SetThreadContext (th->h, &th->context);
> +             else
> +               CHECK (SetThreadContext (th->h, &th->context));

Rather than duplicate the call to SetThreadContext, perhaps
another way of doing it would be:

    DWORD status;

    status = SetThreadContext (th->h, &th->context);
    if (!killed)
      CHECK (status)

(not a strong suggestion, feel free to ignore)

-- 
Joel