From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 7CD8B3892453; Wed,  3 Feb 2021 07:57:21 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7CD8B3892453
From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug debug/98946] GCC generating incorrect relocation R_386_GOTOFF
 in .debug-info for x86 (32)
Date: Wed, 03 Feb 2021 07:57:21 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: debug
X-Bugzilla-Version: 10.2.1
X-Bugzilla-Keywords: wrong-debug
X-Bugzilla-Severity: normal
X-Bugzilla-Who: jakub at gcc dot gnu.org
X-Bugzilla-Status: RESOLVED
X-Bugzilla-Resolution: INVALID
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: bug_status resolution
Message-ID: <bug-98946-4-WGK5LKaDDy@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-98946-4@http.gcc.gnu.org/bugzilla/>
References: <bug-98946-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Wed, 03 Feb 2021 07:57:21 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98946

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |INVALID

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
No, that is a lld bug, there is no such rule that would say these relocatio=
ns
can't be applied against non-allocated or debug sections.
GCC var-tracking figures out that the last argument passed to __assert_fail=
 is
equivalent to %ebx + __PRETTY_FUNCTION__.0@gotoff, but can't prove that %ebx
will be equal to __GLOBAL_OFFSET_TABLE__, so can't emit there just
__PRETTY_FUNCTION__.0 - while %ebx must be some __GLOBAL_OFFSET_TABLE__
pointer, it could have been adjusted, so e.g. it could be
__GLOBAL_OFFSET_TABLE__ + index and the needed value would then be
__PRETTY_FUNCTION__.0 + index.
And we want to emit as compact debug info as possible, so emitting it as
%ebx + __PRETTY_FUNCTION__.0@gotoff rather than say (%ebx -
__GLOBAL_OFFSET_TABLE__) + __PRETTY_FUNCTION__.0, especially because
referencing __GLOBAL_OFFSET_TABLE__ symbol in assembly poses interesting
problem (implies special relocations).=