Re: [PULL 8/9] pc-bios/s390-ccw: Allow building with Clang, too

[Thomas Huth <thuth@redhat.com>]

On 12/05/2021 16.00, Thomas Huth wrote:
> On 12/05/2021 15.40, Thomas Huth wrote:
>> On 12/05/2021 13.53, Philippe Mathieu-Daudé wrote:
>>> On 5/10/21 9:35 AM, Thomas Huth wrote:
>>>> Clang unfortunately does not support generating code for the z900
>>>> architecture level and starts with the z10 instead. Thus to be able
>>>> to support compiling with Clang, we have to check for the supported
>>>> compiler flags. The disadvantage is of course that the bios image
>>>> will only run with z10 guest CPUs upwards (which is what most people
>>>> use anyway), so just in case let's also emit a warning in that case
>>>> (we will continue to ship firmware images that have been pre-built
>>>> with GCC in future releases, so this should not impact normal users,
>>>> too).
>>>>
>>>> Message-Id: <20210502174836.838816-5-thuth@redhat.com>
>>>> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>>>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>>>> ---
>>>>   configure                 | 9 ++++++++-
>>>>   pc-bios/s390-ccw/Makefile | 3 ++-
>>>>   2 files changed, 10 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/configure b/configure
>>>> index 4f374b4889..5ebc937746 100755
>>>> --- a/configure
>>>> +++ b/configure
>>>> @@ -5417,9 +5417,16 @@ if { test "$cpu" = "i386" || test "$cpu" = 
>>>> "x86_64"; } && \
>>>>   fi
>>>>   # Only build s390-ccw bios if we're on s390x and the compiler has 
>>>> -march=z900
>>>> +# or -march=z10 (which is the lowest architecture level that Clang 
>>>> supports)
>>>>   if test "$cpu" = "s390x" ; then
>>>>     write_c_skeleton
>>>> -  if compile_prog "-march=z900" ""; then
>>>> +  compile_prog "-march=z900" ""
>>>> +  has_z900=$?
>>>> +  if [ $has_z900 = 0 ] || compile_prog "-march=z10" ""; then
>>>> +    if [ $has_z900 != 0 ]; then
>>>> +      echo "WARNING: Your compiler does not support the z900!"
>>>> +      echo "         The s390-ccw bios will only work with guest CPUs 
>>>> >= z10."
>>>> +    fi
>>>>       roms="$roms s390-ccw"
>>>>       # SLOF is required for building the s390-ccw firmware on s390x,
>>>>       # since it is using the libnet code from SLOF for network booting.
>>>> diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
>>>> index 83fb1afb73..cee9d2c63b 100644
>>>> --- a/pc-bios/s390-ccw/Makefile
>>>> +++ b/pc-bios/s390-ccw/Makefile
>>>> @@ -34,7 +34,8 @@ QEMU_CFLAGS += $(call cc-option,-Werror 
>>>> $(QEMU_CFLAGS),-Wno-stringop-overflow)
>>>>   QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks 
>>>> -fno-common -fPIE
>>>>   QEMU_CFLAGS += -fwrapv -fno-strict-aliasing 
>>>> -fno-asynchronous-unwind-tables
>>>>   QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector)
>>>> -QEMU_CFLAGS += -msoft-float -march=z900
>>>> +QEMU_CFLAGS += -msoft-float
>>>> +QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS),-march=z900,-march=z10)
>>>>   QEMU_CFLAGS += -std=gnu99
>>>>   LDFLAGS += -Wl,-pie -nostdlib
>>>
>>> This broke the travis-ci  "[s390x] Clang (disable-tcg)" job:
>>> https://travis-ci.org/github/qemu/qemu/jobs/770794417#L1776
>>>
>>> Description:    Ubuntu 18.04.4 LTS
>>> Release:    18.04
>>> Codename:    bionic
>>>
>>> $ clang --version
>>> clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
>>> Target: s390x-ibm-linux-gnu
>>
>> Darn! ... I guess we should switch to the clang-10 package which should be 
>> available there, since Daniel also plans to raise the minimum Clang 
>> version to 7.0 now ... I'll try to come up with a patch...
> 
> Never mind to update travis.yml ... I just read:
> 
> https://blog.travis-ci.com/2021-05-07-orgshutdown
> 
> i.e. travis-ci.org will be finally really be shut down at the end of the 
> month. We should remove our travis-ci.yml file now.

Never mind the never mind ... as I just learnt, Travis now offers free CI 
again for s390x and aarch64, so we certainly should not remove the 
travis-ci.yml file yet.

  Thomas