Re: Breakpoint commands in MI mode and "backtrace"

Eli Zaretskii
2017-10-08T20:03:16Z

> Cc: gdb@sourceware.org
> From: Simon Marchi <simark@simark.ca>
> Date: Sun, 8 Oct 2017 15:24:21 -0400
>
> But here's the equivalent version with the corresponding cleanup,
> that applies on the 8.0 branch:
>
> diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
> index f1db954a69..34ae4966de 100644
> --- a/gdb/cli/cli-script.c
> +++ b/gdb/cli/cli-script.c
> @@ -472,6 +472,8 @@ print_command_trace (const char *cmd)
> printf_filtered ("%s\n", cmd);
> }
>
> +static void restore_interp (void *arg);
> +
> enum command_control_type
> execute_control_command (struct command_line *cmd)
> {
> @@ -491,8 +493,14 @@ execute_control_command (struct command_line *cmd)
> {
> /* A simple command, execute it and return. */
> std::string new_line = insert_user_defined_cmd_args (cmd->line);
> - execute_command (&new_line[0], 0);
> +
> + struct interp *old_interp = interp_set_temp (INTERP_CONSOLE);
> + struct cleanup *old_chain = make_cleanup (restore_interp, old_interp);
> +
> + current_interpreter ()->exec (&new_line[0]);
> ret = cmd->control_type;
> +
> + do_cleanups (old_chain);
> break;
> }

Thanks, this works, but it seems to fail hookpost hooks. The Emacs
.gdbinit file defines a hookpost-backtrace command to produce a
Lisp-level backtrace, and with this change that fails:

~"Lisp Backtrace:\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"
&"Argument to arithmetic operation not a number or boolean.\n"

Whereas without the patch, the C-level backtrace is not shown, but the
Lisp-level backtrace is shown correctly:

~"Lisp Backtrace:\n"
~"\"redraw-display\""
~" (0x82de90)\n"
~"\"funcall-interactively\""
~" (0x82de88)\n"
~"\"call-interactively\""
~" (0x82e1e0)\n"
~"\"command-execute\""
~" (0x82e738)\n"
~"\"execute-extended-command\""
~" (0x82ee20)\n"
~"\"funcall-interactively\""
~" (0x82ee18)\n"
~"\"call-interactively\""
~" (0x82f220)\n"
~"\"command-execute\""
~" (0x82f748)\n"

> > In any case, there are more instances of calls to execute_command in
> > that function, and I guess they all need to be changed like that?
>
> I don't see any other call.

You are right, sorry.

Thanks.