Re: [PATCH V2] tools/virtio: fix build break for aarch64

[Xuan Zhuo]

On Thu, 23 Mar 2023 12:00:24 +0800, "Peng Fan (OSS)" <peng.fan@xxxxxxxxxxx> wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
>
> "-mfunction-return=thunk -mindirect-branch-register" are only valid
> for x86. So introduce compiler operation check to avoid such issues
>
> Fixes: 0d0ed4006127 ("tools/virtio: enable to build with retpoline")
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
>
> V2:
>  Use /dev/null as output dest
>  Move call cc-option to the original CFLAGS
>
>  tools/virtio/Makefile | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/tools/virtio/Makefile b/tools/virtio/Makefile
> index 7b7139d97d74..d128925980e0 100644
> --- a/tools/virtio/Makefile
> +++ b/tools/virtio/Makefile
> @@ -4,7 +4,18 @@ test: virtio_test vringh_test
>  virtio_test: virtio_ring.o virtio_test.o
>  vringh_test: vringh_test.o vringh.o virtio_ring.o
>
> -CFLAGS += -g -O2 -Werror -Wno-maybe-uninitialized -Wall -I. -I../include/ -I ../../usr/include/ -Wno-pointer-sign -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD -U_FORTIFY_SOURCE -include ../../include/linux/kconfig.h -mfunction-return=thunk -fcf-protection=none -mindirect-branch-register
> +try-run = $(shell set -e;		\
> +	if ($(1)) >/dev/null 2>&1;	\
> +	then echo "$(2)";		\
> +	else echo "$(3)";		\
> +	fi)
> +
> +__cc-option = $(call try-run,\
> +	$(1) -Werror $(2) -c -x c /dev/null -o /dev/null,$(2),)
> +cc-option = $(call __cc-option, $(CC),$(1))

Can we sqush these to one function?

> +
> +CFLAGS += -g -O2 -Werror -Wno-maybe-uninitialized -Wall -I. -I../include/ -I ../../usr/include/ -Wno-pointer-sign -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD -U_FORTIFY_SOURCE -include ../../include/linux/kconfig.h $(call cc-option,-mfunction-return=thunk) $(call cc-option,-fcf-protection=none) $(call cc-option,-mindirect-branch-register)

nit: this line is too long. Can we split it?

Thanks.

> +
>  CFLAGS += -pthread
>  LDFLAGS += -pthread
>  vpath %.c ../../drivers/virtio ../../drivers/vhost
> --
> 2.37.1
>