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From: "Schimpe, Christina" <christina.schimpe@intel.com>
To: Pedro Alves <pedro@palves.net>,
	"gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
Cc: "tom@tromey.com" <tom@tromey.com>,
	"aburgess@redhat.com" <aburgess@redhat.com>,
	"eliz@gnu.org" <eliz@gnu.org>
Subject: RE: [PATCH v4 3/3] gdb: Remove workaround for the vCont packet
Date: Mon, 30 Jan 2023 14:35:28 +0000	[thread overview]
Message-ID: <CY4PR11MB200532C3BAC78874D38326C0F9D39@CY4PR11MB2005.namprd11.prod.outlook.com> (raw)
In-Reply-To: <32fd8757-bc08-07d1-bbdd-f6da30137bc8@palves.net>

Hi Pedro,

> On 2022-12-21 1:39 p.m., Christina Schimpe wrote:
> > The workaround for the vCont packet is no longer required due to the
> > former commit "gdb: Make global feature array a per-remote target array".
> > The vCont packet is now checked once when the connection is started
> > and the supported vCont actions are set to the target's remote state
> > attribute.
> 
> So this patch is actually doing two things:
> 
>  #1 - removing the supports_vCont_probed hack.
> 
>  #2 - moving the vCont probing earlier, to connection start.
> 
> To eliminate the workaround, you don't need #2.  Doing just #1 would simply get
> us back to how it worked before the multi-target support.  #2 is an extra change.
> 
> I don't think there's any particular reason for deferring probing for vCont
> support up until we first try to resume.  Looking at the history, we find that
> vCont was designed in 2003, here:
> 
>   https://marc.info/?l=gdb-patches&w=2&r=30&s=vcont&q=b
> 
> and particularly "vCont?" probing was discussed here:
> 
>   https://marc.info/?l=gdb-patches&m=158570765842635&w=2
> 
> while the qSupported generic probing feature (done at connection startup) was
> only invented later in 2006:
> 
>   https://sourceware.org/legacy-ml/gdb/2006-05/msg00372.html
> 
> Even without qSupported (otherwise I bet we wouldn't have vCont? but instead
> the support would have been reported via qSupported), it's not clear why Daniel
> didn't do the probing at initial connection time, I didn't find any message
> specifically about that.  Likely it was written that way just to keep all the related
> code together, I guess.
> 
> Thus, the patch is OK.  But I wanted to explicitly state the two unrelated changes
> here for the record, and dig a bit at the history to figure out whether we'd be
> breaking some subtle use case.
> 
> Thanks for this.  Happy to see it finally done.
> 
> Pedro Alves

Thank you for the investigation, I pushed the patch now.

Best Regards,
Christina
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

  reply	other threads:[~2023-01-30 14:35 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-21 13:39 [PATCH v4 0/3] Apply fixme notes for multi-target support Christina Schimpe
2022-12-21 13:39 ` [PATCH v4 1/3] gdb: Make global feature array a per-remote target array Christina Schimpe
2022-12-21 14:08   ` Eli Zaretskii
2023-01-23 17:42   ` Pedro Alves
2023-01-30 14:34     ` Schimpe, Christina
2022-12-21 13:39 ` [PATCH v4 2/3] gdb: Add per-remote target variables for memory read and write config Christina Schimpe
2022-12-21 14:13   ` Eli Zaretskii
2023-01-23 17:43   ` Pedro Alves
2023-01-30 14:34     ` Schimpe, Christina
2022-12-21 13:39 ` [PATCH v4 3/3] gdb: Remove workaround for the vCont packet Christina Schimpe
2023-01-23 17:46   ` Pedro Alves
2023-01-30 14:35     ` Schimpe, Christina [this message]
2023-01-16  8:58 ` [PING][PATCH v4 0/3] Apply fixme notes for multi-target support Schimpe, Christina

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