Re: [Qemu-devel] [PATCH 4/8] convert libqemuutil to meson

["Daniel P. Berrangé" <berrange@redhat.com>]

On Sat, Jul 27, 2019 at 07:20:15PM +0100, Peter Maydell wrote:
> On Sat, 27 Jul 2019 at 13:24, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > On 27/07/19 09:16, Markus Armbruster wrote:
> > > We started with a single trace-events.  That wasn't good, so we split it
> > > up into one per directory.  That isn't good, so what about splitting it
> > > up into one per source file?  Pass -DTRACE_HEADER='"trace-DIR-FOO.h"
> > > instead of -DTRACE_HEADER='"trace-DIR.h"' when compiling DIR/FOO.c.
> >
> > For Make this would all work great, however not for Meson because it
> > doesn't allow per-file compile flags.
> 
> Apologies for randomly parachuting into this email thread, but if
> Meson doesn't support per-file compile flags then what's the plan
> for handling the cases where we currently need per-file compile flags ?

I'd suggest we don't actually /need/ per-file compiler flags in most
cases. eg when we add  $foo.o-libs += $(FOO_LIBS) that's not really
a per-file setting when it gets expanded onto the final linker line.
Its just a "-lfoo" that gets used for the library as a while.

> (This is one of the things that I thought was quite a nice move
> forward in our make infrastructure -- we now have clean syntax
> for saying "these files need to be built with these warnings disabled
> or these extra include paths or whatever" and also "these files
> imply we're going to need to link against library X".)

You can disable warnings selectively per file using a Pragma in the
source.

Regards,
Daniel
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