GNU bug report logs - #79360
30.2; lldb shows incorrect code location when no column number is available

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Gustav Hållberg <gustav <at> gmail.com>
Subject: bug#79360: closed (Re: bug#79360: 30.2; lldb shows incorrect code
 location when no column number is available)
Date: Sat, 06 Sep 2025 09:07:02 +0000

[Message part 1 (text/plain, inline)]

Your bug report

#79360: 30.2; lldb shows incorrect code location when no column number is available

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 79360 <at> debbugs.gnu.org.

-- 
79360: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=79360
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Eli Zaretskii <eliz <at> gnu.org>
To: Gustav Hållberg <gustav <at> gmail.com>
Cc: 79360-done <at> debbugs.gnu.org
Subject: Re: bug#79360: 30.2; lldb shows incorrect code location when no
 column number is available
Date: Sat, 06 Sep 2025 12:06:14 +0300

> From: Gustav Hållberg <gustav <at> gmail.com>
> Date: Mon, 1 Sep 2025 19:09:10 +0200
> Cc: 79360 <at> debbugs.gnu.org
> 
> It is a bug in the emacs M-x lldb command.
> 
> lldb (the tool) correctly sends an empty column field when it has no column number debug information.
> 
> If you look at the patch you'll see that the gud.el regexp (correctly) matches an empty digit sequence for the
> column number field, but that (incorrectly) is treated as column zero (which doesn't exist) rather than an
> absent column number field.

Thanks, I've now installed the change on the master branch, and I'm
therefore closing this bug.

[Message part 3 (message/rfc822, inline)]

From: Gustav Hållberg <gustav <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 30.2;
 lldb shows incorrect code location when no column number is available
Date: Mon, 1 Sep 2025 16:42:33 +0200

[Message part 4 (text/plain, inline)]

In (lldb), there is a bug that positions the source code location on the
last character of the previous line if lldb doesn't report a column number.

Example, save the following as "t.s" and compile (on x86-64) with "gcc -g
t.s -o t":

        .global _main
_main:
        xor %eax,%eax
        ret

and debug using (lldb "lldb ./t"):

(lldb) *b main*
  :
(lldb) *run*
  :
(lldb)
*disas*t`main:
    0x555555555129 <+0>: xorl   %eax, %eax
->  0x55555555512b <+2>: retq

but the source code location ends up at the last character of the "xor
%eax..." line.

Attaching proposed pach against 66ef930ebea4618c1dac71a09495766476ced1d6.

[Message part 5 (text/html, inline)]

[0001-lldb-bugfix-source-code-location-without-column.patch (application/octet-stream, attachment)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.