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Re: [PATCH] Use "switch_to_thread" more thoroughly on gdbserver
On Thursday, September 21 2017, Pedro Alves wrote:
> On 09/15/2017 07:25 PM, Sergio Durigan Junior wrote:
>> On Friday, September 15 2017, Pedro Alves wrote:
>>
>>> Do you remember why that check is there in switch_to_thread in the
>>> first place, as opposed to, say, an assertion?
>>
>> I tried to do some archaeology here and find the patch that implemented
>> this feature, and it seems to me that the patch always used 'if' instead
>> of an 'assert'.
>
> Yeah, gdbserver's switch_to_thread was added with your fork
> inferior sharing series.
Exactly.
>> Maybe that's because GDB's version of switch_to_thread
>> also doesn't assert that ptid != minus_one_ptid...
>
> Except it does:
>
> static void
> switch_to_thread (thread_info *thr)
> {
> gdb_assert (thr != NULL);
> ^^^^^^^^^^^^^^^^^^^^^^^^
> ...
>
> Called from:
>
> void
> switch_to_thread (ptid_t ptid)
> {
> if (ptid == null_ptid)
> switch_to_no_thread ();
> else
> switch_to_thread (find_thread_ptid (ptid));
> }
>
> ... and find_thread_ptid returns NULL because there's
> never a thread with ptid == minus_one_ptid.
Oh. There's an overload, then. And there's also a check to see if ptid
== null_ptid. Maybe it's worth extending gdbserver's switch_to_thread
to mimic that behaviour.
--
Sergio
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