Re: [PULL 0/1] Quick fix patches

[Warner Losh <imp@bsdimp.com>]

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On Wed, Aug 30, 2023, 7:26 AM Thomas Huth <thuth@redhat.com> wrote:

> On 30/08/2023 15.16, Stefan Hajnoczi wrote:
> > Hi,
> > The patch introduces the following build failure:
> >
> > cc -m64 -mcx16 -Isubprojects/libvhost-user/libvhost-user.a.p
> > -Isubprojects/libvhost-user -I../subprojects/libvhost-user
> > -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu99 -O2 -g
> > -Wsign-compare -Wdeclaration-after-statement -Wstrict-aliasing
> > -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing
> > -fno-common -fwrapv -fPIE -pthread -D_GNU_SOURCE -MD -MQ
> > subprojects/libvhost-user/libvhost-user.a.p/libvhost-user.c.o -MF
> > subprojects/libvhost-user/libvhost-user.a.p/libvhost-user.c.o.d -o
> > subprojects/libvhost-user/libvhost-user.a.p/libvhost-user.c.o -c
> > ../subprojects/libvhost-user/libvhost-user.c
> > In file included from ../subprojects/libvhost-user/include/atomic.h:18,
> > from ../subprojects/libvhost-user/libvhost-user.c:53:
> > ../subprojects/libvhost-user/include/compiler.h:38:40: error: missing
> > binary operator before token "("
> > 38 | #if defined(__clang__) &&
> __has_warning("-Waddress-of-packed-member")
> > | ^
> >
> > https://gitlab.com/qemu-project/qemu/-/jobs/4981576093
>
> IIRC older versions of GCC do not have __has_warning() yet, so if you want
> to use this in compiler.h, you have to do it below the line in compiler.h
> that adds this:
>
> #ifndef __has_warning
> #define __has_warning(x) 0 /* compatibility with non-clang compilers */
> #endif
>

This already works for linux-user. If there are gcc versions that break,
our current CI jobs don't show it. Why add complexity for unsupported gcc
versions? And how do I know I got it right?

I'm really starting to think the feedback 'move it to compilers.h' should
have just been ignored... it's turning into a lot of my time to correct
that I don't have when I'm also out of CI minutes to test with.

Warner





>   HTH,
>    Thomas
>
>

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