Re: [PATCH 6/9] gdb: Implement 'bt shadow' to print the shadow stack backtrace.

[Eli Zaretskii <eliz@gnu.org>]

> From: Christina Schimpe <christina.schimpe@intel.com>
> Date: Tue, 23 Sep 2025 11:18:39 +0000
> 
> Add a subcommand 'bt shadow' for the ordinary backtrace command which
> prints the shadow stack backtrace.
> Similar to the ordinary backtrace command 'bt shadow' can be configured
> using COUNT and the command line option -frame-info.  However, we always
> print the address and the command is not affected by the setting
> "print address" as well as the setting "print frame-info location-and-address".
> Also we do not print the frame arguments.
> 
> Usage: backtrace|bt shadow [OPTION]... [COUNT | -COUNT]
> 
> Help output:
> ~~
> (gdb) help bt shadow
> Print backtrace of all shadow stack frames, or innermost COUNT frames.
> Usage: backtrace shadow [OPTION]... [COUNT | -COUNT]

Thanks, but I wonder if this UI is the best we can come up with.
The "backtrace" command doesn't currently have non-option arguments
except COUNT.  We have just got rid of qualifier arguments like "full"
and "hide".  Instead of introducing qualifier arguments anew, why not
go the way of thread-related commands and add a new command "shadow",
so the user could say "shadow backtrace" and maybe in the future also
other sub-commands?

Also, a question: can I say something like "thread apply 1-10 bt shadow"?

> +* New commands
> +
> +backtrace shadow [option]... [count | -count]
> +bt shadow [option]... [count | -count]
> +  Print backtrace of all shadow stack frames, or innermost 'count' frames.
> +  The command is a subcommand of the ordinary backtrace command.
> +
>  *** Changes in GDB 17

This part is okay (subject to the general comment above).

> +This is how a shadow stack backtrace looks like on amd64:
> +@smallexample
> +@group
> +#0  0x000000000040111f in call1 at amd64-shadow-stack.c:14
> +#1  0x000000000040112f in main at amd64-shadow-stack.c:21
> +#2  0x00007ffff7c3fe70 in __libc_start_call_main at ../sysdeps/nptl/libc_start_call_main.h:58

This line is too long.  Since this is just an example, I suggest to
make it artificially shorter by editing the names of the functions and
file names.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>