Re: [Qemu-devel] [PATCH] configure: Disable (clang) initializer-overrides warnings

[Igor Mitsyanko]

On 10/27/2012 8:51 PM, Blue Swirl wrote:
> Thanks, applied.
>
> On Sun, Oct 14, 2012 at 8:00 PM, Peter Maydell <address@hidden> wrote:
> > Disable clang's initializer-overrides warnings, as QEMU makes significant
> > use of the pattern of initializing an array with a range-based default
> > entry like
> >      [0 ... 0x1ff] = { GPIO_NONE, 0 }
> > followed by specific entries which override that default, and clang
> > would otherwise warn "initializer overrides prior initialization of
> > this subobject" when it encountered the specific entry.
> >
> > Signed-off-by: Peter Maydell <address@hidden>
> > ---
> > This is basically a judgement that our coding style is legitimate
> > and the compiler is being overly alarmist. I don't think we would
> > benefit from trying to silence the warnings and I can't think of
> > a clean way of doing so...
> >
> > NB that gcc will happily ignore -Wno-wombat warnings that it doesn't
> > happen to recognize. (For compilers that don't accept-and-ignore the flag
> > configure will identify this and not use it.)

I encountered strange behavior of latest mingw gcc, it ignores 
unrecognized -Wno-wombat options only in case if no other warnings are 
issued (configure gccflags test doesn't issue any), otherwise I get this:

cc1.exe: warning: unrecognized command line option 
"-Wno-initializer-overrides" [enabled by default]

This is probably a bug in mingw GCC (or perhaps I'm using it wrong), but 
anyway, this makes QEMU mingw build output very noisy.

> > Blue Swirl previously submitted a patch which enabled this flag
> > (among others):
> > http://lists.gnu.org/archive/html/qemu-devel/2012-07/msg04203.html
> >
> > I haven't found the other two flags in that patch to be required.
> >
> >   configure | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/configure b/configure
> > index 353d788..f78cfc5 100755
> > --- a/configure
> > +++ b/configure
> > @@ -1187,6 +1187,7 @@ gcc_flags="-Wold-style-declaration -Wold-style-definition 
> > -Wtype-limits"
> >   gcc_flags="-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers 
> > $gcc_flags"
> >   gcc_flags="-Wmissing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
> >   gcc_flags="-fstack-protector-all -Wendif-labels $gcc_flags"
> > +gcc_flags="-Wno-initializer-overrides $gcc_flags"
> >   # Note that we do not add -Werror to gcc_flags here, because that would
> >   # enable it for all configure tests. If a configure test failed due
> >   # to -Werror this would just silently disable some features,
> > --
> > 1.7.11.4