From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:55274)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <sw@weilnetz.de>) id 1Vv6ts-0001hn-R9
	for qemu-devel@nongnu.org; Mon, 23 Dec 2013 09:54:36 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <sw@weilnetz.de>) id 1Vv6to-0002j1-QL
	for qemu-devel@nongnu.org; Mon, 23 Dec 2013 09:54:32 -0500
Received: from [2a03:4000:1::4e2f:c7ac:d] (port=45251
	helo=v220110690675601.yourvserver.net)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <sw@weilnetz.de>) id 1Vv6to-0002i5-KP
	for qemu-devel@nongnu.org; Mon, 23 Dec 2013 09:54:28 -0500
Message-ID: <52B84E97.3050002@weilnetz.de>
Date: Mon, 23 Dec 2013 15:54:15 +0100
From: Stefan Weil <sw@weilnetz.de>
MIME-Version: 1.0
References: <20131223145216.GA22663@redhat.com>
In-Reply-To: <20131223145216.GA22663@redhat.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [Qemu-devel] [PATCH v3] target-arm: fix build with gcc 4.8.2
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: "Michael S. Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>, Alexander Graf <agraf@suse.de>, Richard Henderson <rth@twiddle.net>

Am 23.12.2013 15:52, schrieb Michael S. Tsirkin:
> commit 5ce4f35781028ce1aee3341e6002f925fdc7aaf3
>     "target-arm: A64: add set_pc cpu method"
>
> introduces an array aarch64_cpus which is zero
> size if this code is built without CONFIG_USER_ONLY.
> In particular an attempt to iterate over this array produces a warning
> under gcc 4.8.2:
>
>  CC    aarch64-softmmu/target-arm/cpu64.o
> /scm/qemu/target-arm/cpu64.c: In function =E2=80=98aarch64_cpu_register=
_types=E2=80=99:
> /scm/qemu/target-arm/cpu64.c:124:5: error: comparison of unsigned
> expression < 0 is always false [-Werror=3Dtype-limits]
>      for (i =3D 0; i < ARRAY_SIZE(aarch64_cpus); i++) {
>      ^
> cc1: all warnings being treated as errors
>
> This is the result of ARRAY_SIZE being an unsigned type,
> causing "i" to be promoted to unsigned int as well.
>
> As zero size arrays are a gcc extension, it seems
> cleanest to add a dummy element with NULL name,
> and test for it during registration.
>
> We'll be able to drop this when we add more CPUs.
>
> Cc: Alexander Graf <agraf@suse.de>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Richard Henderson <rth@twiddle.net>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> changes from v2:
>     add more comments
> changes from v1:
>     add a comment
>
>  target-arm/cpu64.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/target-arm/cpu64.c b/target-arm/cpu64.c
> index 04ce879..60acd24 100644
> --- a/target-arm/cpu64.c
> +++ b/target-arm/cpu64.c
> @@ -58,6 +58,7 @@ static const ARMCPUInfo aarch64_cpus[] =3D {
>  #ifdef CONFIG_USER_ONLY
>      { .name =3D "any",         .initfn =3D aarch64_any_initfn },
>  #endif
> +    { .name =3D NULL } /* TODO: drop when we support more CPUs */
>  };
> =20
>  static void aarch64_cpu_initfn(Object *obj)
> @@ -100,6 +101,11 @@ static void aarch64_cpu_register(const ARMCPUInfo =
*info)
>          .class_init =3D info->class_init,
>      };
> =20
> +    /* TODO: drop when we support more CPUs - all entries will have na=
me set */
> +    if (!info->name) {
> +        return;
> +    }
> +
>      type_info.name =3D g_strdup_printf("%s-" TYPE_ARM_CPU, info->name)=
;
>      type_register(&type_info);
>      g_free((void *)type_info.name);

Reviewed-by: Stefan Weil <sw@weilnetz.de>