On 23 December 2013 11:56, Michael S. Tsirkin <m...@redhat.com> wrote:
> 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:
>
> CC aarch64-softmmu/target-arm/cpu64.o
> /scm/qemu/target-arm/cpu64.c: In function ‘aarch64_cpu_register_types’:
> /scm/qemu/target-arm/cpu64.c:124:5: error: comparison of unsigned
> expression < 0 is always false [-Werror=type-limits]
> for (i = 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.
I guess this is a new gcc warning, since this all builds
fine for me (gcc 4.6.3).
> 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.
>
> Cc: Alexander Graf <ag...@suse.de>
> Cc: Peter Maydell <peter.mayd...@linaro.org>
> Cc: Richard Henderson <r...@twiddle.net>
> Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
> ---
>
> I have queued this in my tree since it prevents me from
> being able to build and test properly.
> Pls review and ack.
>
> target-arm/cpu64.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/target-arm/cpu64.c b/target-arm/cpu64.c
> index 04ce879..2efe189 100644
> --- a/target-arm/cpu64.c
> +++ b/target-arm/cpu64.c
> @@ -58,6 +58,7 @@ static const ARMCPUInfo aarch64_cpus[] = {
> #ifdef CONFIG_USER_ONLY
> { .name = "any", .initfn = aarch64_any_initfn },
> #endif
> + { .name = NULL }
> };
>
> static void aarch64_cpu_initfn(Object *obj)
> @@ -100,6 +101,10 @@ static void aarch64_cpu_register(const ARMCPUInfo *info)
> .class_init = info->class_init,
> };
>
> + if (!info->name) {
> + return;
> + }
> +
> type_info.name = g_strdup_printf("%s-" TYPE_ARM_CPU, info->name);
> type_register(&type_info);
> g_free((void *)type_info.name);
At a minimum, if we take this approach we should add TODO comments
to the effect that the NULL terminator and the if() can be removed
when the first real AArch64 CPU is added.
I think I'd rather put the if (!info->name) continue into the function
which is doing the looping over the array.
thanks
-- PMM
