Re: [Qemu-devel] spice/qlx: atomic-alignment error with clang-7

[Peter Maydell]

On 18 July 2018 at 16:12, Paolo Bonzini <address@hidden> wrote:
> On 18/07/2018 16:56, Philippe Mathieu-Daudé wrote:
>> Using clang-7 (Debian) on x86_64 to build v3.0.0-rc1.
>>
>> Not a regression, it was probably always there:
>>
>> $ ./configure --cc=clang-7 && make hw/display/qxl.o
>> hw/display/qxl.c:1884:19: error: misaligned or large atomic operation
>> may incur significant performance penalty [-Werror,-Watomic-alignment]
>>     old_pending = atomic_fetch_or(&d->ram->int_pending, le_events);
>>                   ^
>> include/qemu/atomic.h:206:34: note: expanded from macro 'atomic_fetch_or'
>> #define atomic_fetch_or(ptr, n)  __atomic_fetch_or(ptr, n, __ATOMIC_SEQ_CST)
>>                                  ^
>> 1 error generated.
>
> Hi, this is fixed in the latest SPICE git.  The upstream commit is
>
> https://gitlab.freedesktop.org/spice/spice-protocol/commit/beda5ec7a6848be20c0cac2a9a8ef2a41e8069c1

...so what's the plan for handling existing in-the-wild spice
headers which have this bug? I guess refusing to compile against
those headers would be a bit harsh.

I'll put together a patch that uses the gcc diagnostic pragma
to suppress the warning around this line.

thanks
-- PMM