reverse execution part of the manual is written backwards

  On 4/10/19 3:54 PM, Eli Zaretskii wrote:
>> From: Pedro Alves <palves@redhat.com>
>> Date: Wed, 10 Apr 2019 12:51:36 +0100
>>
>>> +Before using reverse execution, you should first use the @code{record}
>>> +command, so that instructions executed by the program are saved for
>>> +reverse execution later.  @xref{Process Record and Replay}.
>>> +@value{GDBN} provides the following commands to examine the process
>>> +record and execute the program in reverse.
>>
>> This is not correct.  "record" is one way to support reverse execution,
>> but there are others.  For example, "record" is an alias for "record full".
>> "record btrace" also supports reverse debugging.  And then there are
>> remote targets that suppose reverse debugging natively, like system emulators,
>> and you won't type "record" with those at all.  Mozilla's RR is another
>> example.  
>>
>> https://www.gnu.org/software/gdb/news/reversible.html
> 
> Pedro,
> 
> First, thanks for responding, I posted a similar question to gdb@, and
> only got one uncertain response.  What you wrote is much more
> definitive.

Sorry, wish I could answer every question.

> Next, please try to put yourself in the shoes of a GDB user who is
> debugging a native target, let's say on GNU/Linux.  How would such a
> user know what to do to start using the reverse debugging feature?
> 
> The above URL basically says that reverse debugging is available
> natively only on GNU/Linux running on x86 CPUs, and then only if one
> activates "target record".  This is essentially what Paul was saying,
> so he wasn't very far off the mark.  The remote targets are an
> important addition to what Paul said.
> 
> In any case, I think the Reverse Execution section should say
> something about the conditions for using this mode, regardless of
> whether it precedes or follows the chapter about recording and
> replaying.  It probably should simply say what the above URL says at
> its beginning, and then describe the commands to activate the correct
> target, or point to a clear description of those commands elsewhere in
> the manual.  Because right now we have a description of record and
> replay, and we have a description of reverse-execution commands, but
> no "glue" to connect them, and there's no reasonable way for a reader
> to guess what to do to bridge over that chasm.
> 
> Do you agree?
> 

How about this?

From ed99ed89bf0d06edf844eaa018619d617b9bb99b Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Thu, 11 Apr 2019 16:03:33 +0100
Subject: [PATCH] Improve reverse debugging docs

	* gdb.texinfo (Reverse Execution): Mention and xref process record
	and replay.  Mention remote and system emulators.
	(Process Record and Replay): List supported architectures.
	Mention that "record btrace" is only supported on Intel
	processors.
---
 gdb/doc/gdb.texinfo | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)
  

> Cc: eggert@cs.ucla.edu, gdb-patches@sourceware.org
> From: Pedro Alves <palves@redhat.com>
> Date: Thu, 11 Apr 2019 16:54:22 +0100
> 
> > In any case, I think the Reverse Execution section should say
> > something about the conditions for using this mode, regardless of
> > whether it precedes or follows the chapter about recording and
> > replaying.  It probably should simply say what the above URL says at
> > its beginning, and then describe the commands to activate the correct
> > target, or point to a clear description of those commands elsewhere in
> > the manual.  Because right now we have a description of record and
> > replay, and we have a description of reverse-execution commands, but
> > no "glue" to connect them, and there's no reasonable way for a reader
> > to guess what to do to bridge over that chasm.
> > 
> > Do you agree?
> > 
> 
> How about this?

LGTM, thanks.  Paul, does this address your concerns?
  

Pedro Alves wrote:

> How about this?
> 
>  From ed99ed89bf0d06edf844eaa018619d617b9bb99b Mon Sep 17 00:00:00 2001
> From: Pedro Alves <palves@redhat.com>
> Date: Thu, 11 Apr 2019 16:03:33 +0100
> Subject: [PATCH] Improve reverse debugging docs
> 
> 	* gdb.texinfo (Reverse Execution): Mention and xref process record
> 	and replay.  Mention remote and system emulators.
> 	(Process Record and Replay): List supported architectures.
> 	Mention that "record btrace" is only supported on Intel
> 	processors.

Thanks, that patch looks good. Would you please install it?
  

On 4/22/19 7:50 AM, Paul Eggert wrote:
> Pedro Alves wrote:
> 
>> How about this?
>>
>>  From ed99ed89bf0d06edf844eaa018619d617b9bb99b Mon Sep 17 00:00:00 2001
>> From: Pedro Alves <palves@redhat.com>
>> Date: Thu, 11 Apr 2019 16:03:33 +0100
>> Subject: [PATCH] Improve reverse debugging docs
>>
>>     * gdb.texinfo (Reverse Execution): Mention and xref process record
>>     and replay.  Mention remote and system emulators.
>>     (Process Record and Replay): List supported architectures.
>>     Mention that "record btrace" is only supported on Intel
>>     processors.
> 
> Thanks, that patch looks good. Would you please install it?

I've installed it now.

Thanks,
Pedro Alves