From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH v3] test-pmd: Fix pointer aliasing error
Date: Thu, 11 Dec 2014 01:54:21 +0100
Message-ID: <1930269.B5nWyJ5DBl@xps13>
References: <1417663711-19576-1-git-send-email-michael.qiu@intel.com>
 <1417666564-19950-1-git-send-email-michael.qiu@intel.com>
 <533710CFB86FA344BFBF2D6802E60286C9D683@SHSMSX101.ccr.corp.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable
To: "Qiu, Michael" <michael.qiu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, dev-VfR2kkLFssw@public.gmane.org
Return-path: <dev-bounces-VfR2kkLFssw@public.gmane.org>
In-Reply-To: <533710CFB86FA344BFBF2D6802E60286C9D683-0J0gbvR4kThpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request-VfR2kkLFssw@public.gmane.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev-VfR2kkLFssw@public.gmane.org>
List-Help: <mailto:dev-request-VfR2kkLFssw@public.gmane.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request-VfR2kkLFssw@public.gmane.org?subject=subscribe>
Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org
Sender: "dev" <dev-bounces-VfR2kkLFssw@public.gmane.org>

> > app/test-pmd/csumonly.c: In function =E2=80=98get_psd_sum=E2=80=99:=

> > build/include/rte_ip.h:161: error: dereferencing pointer =E2=80=98u=
16=E2=80=99
> >         does break strict-aliasing rules
> > build/include/rte_ip.h:157: note: initialized from here
> >         ...
> >
> > The root cause is that, compile enable strict aliasing by default,
> > while in function rte_raw_cksum() try to convert 'const char *'
> > to 'const uint16_t *'.
> >
> > This patch is one workaround fix.
> >
> > Signed-off-by: Michael Qiu <michael.qiu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > ---
> > v3 --> v2:
> > =09use uintptr_t instead of unsigned long to
> > =09save pointer.
> >
> > v2 --> v1:
> > =09Workaround solution instead of shut off the
> > =09gcc params.
>=20
> This workaround is to solve the compile issue of GCC strict-aliasing(=
Two
> different type pointers should not be point to the same memory addres=
s).
>=20
> For GCC 4.4.7 it will definitely occurs if  flags "-fstrict-aliasing"=

> and "-Wall" used.

Acked-by: Thomas Monjalon <thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@public.gmane.org>>=20

Applied with a comment in the code.

Thanks
--=20
Thomas