Re: [PATCH] Fix alignment of disassemble /r

[Daniel Gutson <daniel dot gutson at tallertechnologies dot com>]

On Thu, Apr 17, 2014 at 1:27 PM, Doug Evans <dje@google.com> wrote:
> On Thu, Apr 17, 2014 at 7:37 AM, Daniel Gutson
> <daniel.gutson@tallertechnologies.com> wrote:
>> So what if I add a new configuration variable, such as
>>      set disassemble-raw-alignment
>> with "off" as default, and if set to on, pad to gdbarch_max_insn_length ?
>
> Presumably some frontends will do their own alignment.
>
> If we went with disassemble-raw-alignment, a boolean value won't help
> x86 much, it's either no alignment or (in general) too much
> whitespace.
> An improvement would be a value from min-insn-length to
> max-insn-length, but that would be problematic in a multi-arch
> debugging scenario.
>
> If we could agree on some minimum alignment for each variable-length
> ISA (5 would be fine for me for x86) then maybe a boolean value could
> be useful ("off" = no alignment, "on" = employ arch-specific minimum).
>
> OTOH, what if we made two passes over the instructions, with the first
> pass computing the maximum instruction length that is present?

I already considered this, but thought that it would be going to be
rejected due to be too much non-performant. Wouldn't each pass
translate in a lot of MI messaging in a case of a remote server? And,
what about screen paginig? I shouldn't iterate over all the range, but
the screen height range only.

I can go for any of the proposed solutions. 5 insn-length was fine for
me. On a side note, I did this since I was debugging some
self-modifying-code where the mis-alignment was driving me crazy.
The two-passes solution is the one I dislike more IMVHO.

Yet another option is to set the disassembly raw alignment width, something like
    set disassemble-raw-width 5
(5 is the amount of insn; 0 means no padding equal to the current
behavior and that would be the default value).

  Daniel.

> [And maybe only doing this for CLI.]



-- 

Daniel F. Gutson
Chief Engineering Officer, SPD


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