From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <sourceware-bugzilla@sourceware.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 60FBF3982422; Thu,  8 Jul 2021 09:34:20 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 60FBF3982422
From: "gprocida at google dot com" <sourceware-bugzilla@sourceware.org>
To: libabigail@sourceware.org
Subject: [Bug default/28060] [libabigail] Invalid offset for bitfields
Date: Thu, 08 Jul 2021 09:34:20 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: libabigail
X-Bugzilla-Component: default
X-Bugzilla-Version: unspecified
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: gprocida at google dot com
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: dodji at redhat dot com
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-28060-9487-9EvVrXibEt@http.sourceware.org/bugzilla/>
In-Reply-To: <bug-28060-9487@http.sourceware.org/bugzilla/>
References: <bug-28060-9487@http.sourceware.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: libabigail@sourceware.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Mailing list of the Libabigail project <libabigail.sourceware.org>
List-Unsubscribe: <https://sourceware.org/mailman/options/libabigail>,
 <mailto:libabigail-request@sourceware.org?subject=unsubscribe>
List-Archive: <https://sourceware.org/pipermail/libabigail/>
List-Help: <mailto:libabigail-request@sourceware.org?subject=help>
List-Subscribe: <https://sourceware.org/mailman/listinfo/libabigail>,
 <mailto:libabigail-request@sourceware.org?subject=subscribe>
X-List-Received-Date: Thu, 08 Jul 2021 09:34:20 -0000

https://sourceware.org/bugzilla/show_bug.cgi?id=3D28060

gprocida at google dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gprocida at google dot com

--- Comment #2 from gprocida at google dot com ---
The problem is in abidw, not abidiff.

I'm guessing that both DW_AT_data_member_location and DW_AT_data_bit_offset
need to be taken into consideration, not just one of them.

The problem exists with -gdwarf-3 and -gdwarf-4, but not -gdwarf-5.

$ head test.{0,1}.c
=3D=3D> test.0.c <=3D=3D
#include <inttypes.h>

struct bigstruct {
  char name[128];
  uint8_t bitfield0:1;
};

uint8_t foo(const struct bigstruct * big) { return big->bitfield0; }

=3D=3D> test.1.c <=3D=3D
#include <inttypes.h>

struct bigstruct {
  char name[128];
  uint8_t bitfield0:1;
  uint8_t bitfield1:1;
};

uint8_t foo(const struct bigstruct * big) { return big->bitfield0; }
$ for i in 0 1; do gcc -Wall -Wextra -g -c test.$i.c; abidw --no-show-locs
test.$i.o > test.$i.xml; done
$ diff -u test.{0,1}.xml
--- test.0.xml  2021-07-08 10:21:30.460919575 +0100
+++ test.1.xml  2021-07-08 10:21:30.516919874 +0100
@@ -1,8 +1,8 @@
-<abi-corpus version=3D'2.0' path=3D'test.0.o' architecture=3D'elf-amd-x86_=
64'>
+<abi-corpus version=3D'2.0' path=3D'test.1.o' architecture=3D'elf-amd-x86_=
64'>
   <elf-function-symbols>
     <elf-symbol name=3D'foo' type=3D'func-type' binding=3D'global-binding'
visibility=3D'default-visibility' is-defined=3D'yes'/>
   </elf-function-symbols>
-  <abi-instr address-size=3D'64' path=3D'test.0.c'
comp-dir-path=3D'/usr/local/google/home/gprocida/dev/libabigail/bitfields2'
language=3D'LANG_C99'>
+  <abi-instr address-size=3D'64' path=3D'test.1.c'
comp-dir-path=3D'/usr/local/google/home/gprocida/dev/libabigail/bitfields2'
language=3D'LANG_C99'>
     <type-decl name=3D'char' size-in-bits=3D'8' id=3D'type-id-1'/>
     <array-type-def dimensions=3D'1' type-id=3D'type-id-1' size-in-bits=3D=
'1024'
id=3D'type-id-2'>
       <subrange length=3D'128' type-id=3D'type-id-3' id=3D'type-id-4'/>
@@ -18,6 +18,9 @@
       <data-member access=3D'public' layout-offset-in-bits=3D'0'>
         <var-decl name=3D'bitfield0' type-id=3D'type-id-7' visibility=3D'd=
efault'/>
       </data-member>
+      <data-member access=3D'public' layout-offset-in-bits=3D'1'>
+        <var-decl name=3D'bitfield1' type-id=3D'type-id-7' visibility=3D'd=
efault'/>
+      </data-member>
     </class-decl>
     <qualified-type-def type-id=3D'type-id-8' const=3D'yes' id=3D'type-id-=
9'/>
     <pointer-type-def type-id=3D'type-id-9' size-in-bits=3D'64' id=3D'type=
-id-10'/>

--=20
You are receiving this mail because:
You are on the CC list for the bug.=