Re: [PATCH 2/2] configure: Add -Wno-gnu-variable-sized-type-not-at-end

[Richard Henderson]

On 9/8/22 09:07, Chenyi Qiang wrote:
> After updating linux headers to v6.0-rc, clang build on x86 target would
> generate warnings like:
>
> target/i386/kvm/kvm.c:470:25: error: field 'info' with variable sized
> type 'struct kvm_msrs' not at the end of a struct or class is a GNU
> extension [-Werror,-Wgnu-variable-sized-type-not-at-end]
>          struct kvm_msrs info;
>                          ^
> target/i386/kvm/kvm.c:1701:27: error: field 'cpuid' with variable sized
> type 'struct kvm_cpuid2' not at the end of a struct or class is a GNU
> extension [-Werror,-Wgnu-variable-sized-type-not-at-end]
>          struct kvm_cpuid2 cpuid;
>                            ^
> target/i386/kvm/kvm.c:2868:25: error: field 'info' with variable sized
> type 'struct kvm_msrs' not at the end of a struct or class is a GNU
> extension [-Werror,-Wgnu-variable-sized-type-not-at-end]
>          struct kvm_msrs info;
>                          ^
>
> Considering that it is OK to use GNU extension in QEMU (e.g. g_auto stuff),
> it is acceptable to turn off this warning, which is only relevant to people
> striving for fully portable C code.
>
> Suggested-by: Daniel P. Berrangé<berrange@redhat.com>
> Signed-off-by: Chenyi Qiang<chenyi.qiang@intel.com>
> ---
>   configure | 1 +
>   1 file changed, 1 insertion(+)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

I'm surprised this is on with -std=gnu11, as opposed to -std=c11.


r~