Re: [PATCH] gdb: New frame_cache_cleared observer.

[Pedro Alves <palves at redhat dot com>]

On 03/30/2015 07:51 PM, Doug Evans wrote:
> On Thu, Mar 26, 2015 at 5:50 AM, Andrew Burgess
> <andrew.burgess@embecosm.com> wrote:
>> Doug, Pedro,
>>
>> * Pedro Alves <palves@redhat.com> [2015-03-26 09:24:27 +0000]:
>>
>>> On 03/25/2015 11:18 PM, Doug Evans wrote:
>>>> On Wed, Mar 25, 2015 at 10:11 AM, Andrew Burgess

>>>>> However, as I don't have an actual use for this observer that I can
>>>>> post upstream (yet) I don't know if this will be acceptable, but given
>>>>> it's a fairly small change I thought I'd try.
>>
>>> Right.  We delete dead code all the time.  So it's better to wait until
>>> is has a use, because otherwise someone could well end up stumbling on it,
>>> noticing it has no uses and decides to send a patch that garbage
>>> collects it.
>>
>> Thanks for looking at my patch, and I understand why you've rejected
>> it for now.
> 
> It's easy enough to prevent people errantly spending cycles submitting
> a patch to delete such code. 

If you mean a comment in the code like "don't delete: this will be
used by an yet-unsubmitted out of tree port, once it's submitted",
I don't agree with that.  Should we put a date on the comment?  If
I read a comment like that saying "2014/09", I'll wonder whether
the port will be submitted in the tree soon enough.  What about
"2013/09"?  Or maybe one should bother to look for the right people
and ask them if that is maybe dead already?  Etc.  It's just better to
avoid such issues.

> OTOH, I'm wondering if a frame-cache-cleared event
> is the right one for your use-case.

*nod*  Without seeing the port it's hard to judge.

> I'm guessing this isn't for frame unwinding,
> otherwise you could just use the existing mechanism
> (e.g., frame_unwind.dealloc_cache).

Thanks,
Pedro Alves