From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Weil <sw@weilnetz.de>
Subject: Re: [PATCH v2 for-1.7] target-i386: Fix build by
 providing stub kvm_arch_get_supported_cpuid()
Date: Thu, 14 Nov 2013 06:40:51 +0100
Message-ID: <52846263.1020608@weilnetz.de>
References: <1384384147-11076-1-git-send-email-peter.maydell@linaro.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Cc: Gleb Natapov <gleb@redhat.com>, kvm@vger.kernel.org, patches@linaro.org,
	Andreas Tobler <andreast@freebsd.org>,
	Anthony Liguori <aliguori@amazon.com>, Paolo Bonzini <pbonzini@redhat.com>,
	Richard Henderson <rth@twiddle.net>
To: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org
Return-path: <qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org>
In-Reply-To: <1384384147-11076-1-git-send-email-peter.maydell@linaro.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>
Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org
Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org
List-Id: kvm.vger.kernel.org

Am 14.11.2013 00:09, schrieb Peter Maydell:
> Fix build failures with clang when KVM is not enabled by
> providing a stub version of kvm_arch_get_supported_cpuid().
> We retain the compile time check that this function isn't
> called when CONFIG_KVM is not set by guarding the stub with
> ifndef __OPTIMIZE__ (we assume that an optimizing build will
> do sufficient constant folding and dead code elimination to
> remove the calls before linking).
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Changes v1->v2:
>  * guard stub with ifndef __OPTIMIZE__
>  * make stub abort() rather than return bogus value
>
>  target-i386/kvm-stub.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/target-i386/kvm-stub.c b/target-i386/kvm-stub.c
> index 11429c4..2b9e801 100644
> --- a/target-i386/kvm-stub.c
> +++ b/target-i386/kvm-stub.c
> @@ -16,3 +16,15 @@ bool kvm_allows_irq0_override(void)
>  {
>      return 1;
>  }
> +
> +#ifndef __OPTIMIZE__
> +/* This function is only called inside conditionals which we
> + * rely on the compiler to optimize out when CONFIG_KVM is not
> + * defined.
> + */
> +uint32_t q(KVMState *env, uint32_t function,
> +                                      uint32_t index, int reg)
> +{
> +    abort();
> +}
> +#endif


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

If you happen to write a v3 patch, g_assert_not_reached would be even
better than abort.

It's impossible to tell why QEMU terminated after an assert without a
debugger,
whereas g_assert_not_reached clearly shows the location.

Regards, Stefan