On 5/25/21 5:13 PM, Philippe Mathieu-Daudé wrote: > On 5/25/21 4:40 PM, Thomas Huth wrote: >> On 25/05/2021 16.31, Cornelia Huck wrote: >>> On Tue, 25 May 2021 16:20:32 +0200 >>> Thomas Huth <th...@redhat.com> wrote: >>> >>>> The -msoft-float switch is not available in older versions of Clang. >>>> Since we rely on the compiler to not generate floating point >>>> instructions >>>> unexpectedly, we block those old compilers now via a test in the >>>> configure >>>> script. Note that for some weird reasons, the Clang compiler only >>>> complains >>>> about the missing soft-float support if no other flags are passed via >>>> "-Wl,..." to the linker. So we have to use "compile_object" instead of >>>> "compile_prog" for this check. >>> >>> Ugh. >> >> It's maybe better to use compile_object for testing -msoft-float anyway >> since it could influence the way of linking against libraries (if I get >> https://reviews.llvm.org/D72189 right). >> >>>> >>>> Signed-off-by: Thomas Huth <th...@redhat.com> >>>> --- >>>> configure | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/configure b/configure >>>> index 676239c697..673419ff31 100755 >>>> --- a/configure >>>> +++ b/configure >>>> @@ -5462,7 +5462,7 @@ if test "$cpu" = "s390x" ; then >>>> write_c_skeleton >>>> compile_prog "-march=z900" "" >>>> has_z900=$? >>>> - if [ $has_z900 = 0 ] || compile_prog "-march=z10" ""; then >>>> + if [ $has_z900 = 0 ] || compile_object "-march=z10 -msoft-float >>>> -Werror"; then >>> >>> Do you believe that we should have caught the various clang >>> specialties now? >> >> Apart from one compiler warning that just popped up today, yes. I'm >> seeing this compiler warning with Clang 12.0 now: >> >> roms/SLOF/lib/libnet/ipv6.c:447:18: warning: variable length array >> folded to constant array as an extension [-Wgnu-folding-constant] >> unsigned short raw[ip6size]; >> ^ >> >> ... not sure what to do with that one yet.
See Eric's explanation: https://www.mail-archive.com/qemu-block@nongnu.org/msg84461.html > > Fix it? =) > > Same class as: > https://gitlab.freedesktop.org/slirp/libslirp/-/commit/6690d55626cc > > -- >8 -- > diff --git a/lib/libnet/ipv6.c b/lib/libnet/ipv6.c > index 6420004..b7daeda 100644 > --- a/lib/libnet/ipv6.c > +++ b/lib/libnet/ipv6.c > @@ -441,10 +441,9 @@ static unsigned short ip6_checksum(struct ip6hdr > *ip6h, unsigned char *packet, > { > int i; > unsigned long checksum; > - const int ip6size = sizeof(struct ip6hdr)/sizeof(unsigned short); > union { > struct ip6hdr ip6h; > - unsigned short raw[ip6size]; > + unsigned short raw[sizeof(struct ip6hdr) / > sizeof(unsigned short)]; > } pseudo; > > memcpy (&pseudo.ip6h, ip6h, sizeof(struct ip6hdr)); > @@ -455,7 +454,7 @@ static unsigned short ip6_checksum(struct ip6hdr > *ip6h, unsigned char *packet, > for (checksum = 0, i = 0; i < bytes; i += 2) > checksum += (packet[i] << 8) | packet[i + 1]; > > - for (i = 0; i < ip6size; i++) > + for (i = 0; i < sizeof(pseudo.raw); i++) > checksum += pseudo.raw[i]; > > checksum = (checksum >> 16) + (checksum & 0xffff); > --- > > Do you want me to send the fix since I have it ready? >
