Re: [RFA] Reverse Debugging, 2/5

[Michael Snyder <msnyder@vmware.com>]

Daniel Jacobowitz wrote:
> On Mon, Oct 06, 2008 at 02:10:18PM -0700, Michael Snyder wrote:
>> Pedro Alves wrote:
>>> On Wednesday 01 October 2008 20:17:54, Michael Snyder wrote:
>>>> +  /* TODO: check target for capability.  */
>>> Can we address this?  If you want to be able to query for support,
>>> it would be a matter of defining a new qSupported feature.
>> OK -- but what about existing targets that support reverse,
>> but don't know about the qSupported query?
>>
>> When I put that comment in, I probably intended an implied
>> question-mark -- that is, I wasn't asserting that a query
>> would be useful, just wondering aloud...
> 
> All qSupported probes can be overridden by a manual setting.  I don't
> feel particularly bad about forcing people to update, if there's a
> workaround - that's part of getting protocol changes merged :-)

I see.  So we would just make them type "set reverse-supported on"
or something like that.

> However, I'm not completely sure it's necessary in this case.  When do
> we check for capability?  If it's only at the appropriate run/continue
> command, then probing is OK - though this would make it hard to,
> e.g., automatically enable IDE buttons.

Well, MI isn't in there yet, though I've heard from a
possible contributor.  How about if we put qSupported
into a later patch as well?

Nothing wrong with the present target implementers being
supported in the first version...


>> Yeah, I hear ya -- I'm not crazy about it either, and I
>> don't think I knew about the idea of adding new tags onto
>> the "T" packet two years ago.
>>
>> But... the discussion about the remote protocol for this
>> happened back in '06.  There are now targets out in the field
>> that implement it this way.  It would be bad form to break them...
> 
> I'm pretty sure nothing about this error was in that discussion.  At
> least, I think I would have objected at the time.

You're probably right.  But it was certainly in my earlier
patch submissions.