[PATCH v2] Add support for the --readnever command-line option (DWARF only)

[Eli Zaretskii]

> From: Sergio Durigan Junior <sergiodj@redhat.com>
> Cc: Yao Qi <qiyaoltc@gmail.com>,  Joel Brobecker <brobecker@adacore.com>,  "gdb-patches\@sourceware.org" <gdb-patches@sourceware.org>
> Date: Wed, 22 Nov 2017 19:54:53 -0500
> 
>   - The patch appears to have been introduced as a workaround, at
>     least initially;
>   - The patch is far from perfect, as it simply shunts the load of
>     DWARF debugging information, without really worrying about the
>     other debug format.
>   - Who really does non-symbolic debugging anyways?
> 
> One use of this is when a user simply wants to do the following
> sequence: attach, dump core, detach. Loading the debugging information
> in this case is an unnecessary cause of delay.

This use case should be mentioned in the manual.  And I think if we
want to accept a patch that is DWARF specific, the name of the option
should reflect that; --readnever sounds misleading to me.

(Another possibility would be to have a "maint dwarf" command to do
the same; maybe it's better.)

> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index ab05a3718d..7d3d651185 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -1037,6 +1037,14 @@ Read each symbol file's entire symbol table immediately, rather than
>  the default, which is to read it incrementally as it is needed.
>  This makes startup slower, but makes future operations faster.
>  
> +@item --readnever
> +@cindex @code{--readnever}
> +Do not read each symbol file's symbolic debug information.  This makes
> +startup faster but at the expense of not being able to perform
> +symbolic debugging.
> +
> +This option is currently limited to debug information in DWARF format.
> +For all other format, this option has no effect.
   ^^^^^^^^^^^^^^^^^^^^
"For the others formats"

And I think we need a NEWS entry for this new feature.

Thanks.