Re: [Qemu-devel] [PATCH v2] rules.mak: Force CFLAGS for all objects in DSO

[Fam Zheng <famz@redhat.com>]

On Tue, 05/12 00:24, Andreas Färber wrote:
> Am 07.05.2015 um 08:55 schrieb Fam Zheng:
> > Because of the trick of process-archive-undefs, all .mo objects, even
> > with --enable-modules, are dependencies of executables.
> > 
> > This breaks CFLAGS propogation because the compiling of module object
> > will happen too early before building for DSO.
> > 
> > With GCC 5, the linking would fail because .o doesn't have -fPIC. Also,
> > BUILD_DSO will be missed. (module-common.o will have it, so the stamp
> > symbol was still liked in .so).
> 
> Did you mean "linked"?

Yes but it's too late, the commit is already applied to qemu.git :(

Fam

> 
> Cheers,
> Andreas
> 
> > 
> > Fix the problem by forcing the CFLAGS on individual .o-cflags during
> > unnest-vars.
> > 
> > Reported-by: Alexander Graf <agraf@suse.de>
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > 
> > ---
> > 
> > v2: Simplify as Paolo suggested, while keeping the CFLAGS of
> > module-common.o
> > ---
> >  rules.mak | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/rules.mak b/rules.mak
> > index 3a05627..aec27f8 100644
> > --- a/rules.mak
> > +++ b/rules.mak
> > @@ -102,7 +102,8 @@ endif
> >  %.o: %.dtrace
> >  	$(call quiet-command,dtrace -o $@ -G -s $<, "  GEN   $(TARGET_DIR)$@")
> >  
> > -%$(DSOSUF): CFLAGS += -fPIC -DBUILD_DSO
> > +DSO_OBJ_CFLAGS := -fPIC -DBUILD_DSO
> > +module-common.o: CFLAGS += $(DSO_OBJ_CFLAGS)
> >  %$(DSOSUF): LDFLAGS += $(LDFLAGS_SHARED)
> >  %$(DSOSUF): %.mo
> >  	$(call LINK,$^)
> > @@ -351,6 +352,7 @@ define unnest-vars
> >          # For non-module build, add -m to -y
> >          $(if $(CONFIG_MODULES),
> >               $(foreach o,$($v),
> > +                   $(eval $($o-objs): CFLAGS += $(DSO_OBJ_CFLAGS))
> >                     $(eval $o: $($o-objs)))
> >               $(eval $(patsubst %-m,%-y,$v) += $($v))
> >               $(eval modules: $($v:%.mo=%$(DSOSUF))),
> > 
> 
> 
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