On 08/03/2017 08:34 AM, Philippe Mathieu-Daudé wrote: > Hi Greg, > > On 08/02/2017 11:47 AM, Greg Kurz wrote: >> Building QEMU on fedora26 with the latest gcc package fails: >> >> CC ppc64-softmmu/target/ppc/kvm.o >> In file included from include/sysemu/hw_accel.h:16:0, >> from target/ppc/kvm.c:31: >> target/ppc/kvm.c: In function ‘kvmppc_booke_watchdog_enable’: >> include/sysemu/kvm.h:449:35: error: ‘args_tmp[i]’ may be used >> uninitialized
>
> This sizeof() use looks unnatural to me. I wonder why not use size_t,
> since this is about sizeof()/ARRAY_SIZE(). The problem seems to come
> from the commit this cast was introduced (61c7bbd236):
>
> target-ppc/kvm.c:1302:21: error: comparison of unsigned expression < 0
> is always false [-Werror=type-limits]
>
> So I'd rather suggest this code, which looks more natural to read to me:
>
> if (ARRAY_SIZE(args_tmp)) {
> for (i = 0; i < ARRAY_SIZE(args_tmp) && ...
For that matter, the existing code is doing:
int i;
i < (int)ARRAY_SIZE(args_tmp)
but wouldn't that be better as:
size_t i;
i < ARRAY_SIZE(args_temp)
I guess we have both the old compilers (per commit 61c7bbd2) and the new
to worry about; although I was unable to reproduce it on Fedora 26 on
x86_64 (is this an architecture-dependent compiler bug?)
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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