RE: [PATCH v3 12/44] gdb, infrun, ze: allow saving process events

["Metzger, Markus T" <markus.t.metzger@intel.com>]

>>>>>> From: Markus Metzger <markus.t.metzger@intel.com>
>>>>>>
>>>>>> When a process stop reply is encountered during stop_all_threads (), a
>>> new
>>>>>> thread with the process' ptid is created and the waitstatus is saved in
>>>>>> that thread.  The effect is that we have a thread with a process ptid and
>>>>>> we dropped the event.
>>>>>>
>>>>>> Save the waitstatus in the inferior, prevent that inferior from resuming,
>>>>>> and return it on the next wait.
>>>>>
>>>>> Can you clarify what a process-wide event is?  Are there instances where
>>>>> a target returns that today, or is something new with intelgt?
>>>>
>>>> This is something new with IntelGT.  An example would be a module load
>>> event.
>>>
>>> Can you point me where this process-wide module load event is added in
>>> the series?  All I can find is the `U` stop reply, which can have
>>> `;library` appended, but I presume that `U` is a thread-specific event.
>>
>> This is added in
>>
>> [PATCH v3 35/44] gdbserver, ze, intelgt: introduce ze-low and intel-ze-low
>targets
>>
>> The intelgt remote target may also send
>>
>>   [remote]   Notification received: Stop:Up1.0;library
>
>Ok, so IIUC, it is an abuse (or re-purpose) of the U stop reply to be
>able to tack the "library" part?  My understanding is that the original
>intent of the U stop reply is to say that we tried to stop a specific
>thread but that it isn't stoppable.  On the other hand, returning a
>process-wide U does not mean "the whole process is unavailable", or does
>it?  I assume it does not change the state of all threads in the process
>to "unavailable".

If there are thread events, we attach the ;library to one of those.
If all threads are either running or unavailable, we still need to tell GDB
about the new library and we chose the U stop reply we introduced
before.  This seemed the easiest solution.

A typical scenario is when the host process starts up, before any work
can be submitted to the device, we need to load device libraries.  At that
time, all device threads are unavailable.

Regards,
Markus.
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