Re: [Qemu-devel] [RFC] Avoiding --whole-archive

[Avi Kivity <avi@redhat.com>]

Andreas Färber wrote:
>> it seems linking object files works while linking static libraries 
>> does not.
>>
>> Architecturally the problem appears to be that the set of objects to 
>> link is determined in Makefile and Makefile.hw but is unknown to 
>> Makefile.target, where the problematic linking happens.
>> As a workaround, I've written the respective set of $(OBJS) to a file 
>> when linking and appending them to the LINK command. Except for two 
>> warnings (../aio.h and ../cache-utils.o linked twice) this works fine 
>> and makes BeOS boot up again.
>
> I came up with another workaround myself, that is using Makefile 
> pseudotargets plus some Makefile magic to fetch the contents of 
> $(OBJS) from Makefile.target. I then misuse the $(sort ) function to 
> eliminate duplicates and thus linker warnings.
>
> Linux/sparc and BeOS/i386 still boot okay despite the reordering.
>
> Comments? 

Way too clever, IMO.  The danger here is that people will fear to edit 
the makefiles after this.

> Better ideas?
>

Maybe a little bit better:

>
> +libqemu_common.a-OBJS:
> +    @for o in $(OBJS); do echo ../$$o; done
> +

libqemu_common.objlist: $(OBJS)
    echo $(sort $(foreach obj, $^, $(shell readlink -f $(obj)))) > $@



>
>  $(QEMU_PROG): LIBS += $(SDL_LIBS) $(COCOA_LIBS) $(CURSES_LIBS) 
> $(BRLAPI_LIBS) $(VDE_LIBS) $(CURL_LIBS)
> -$(QEMU_PROG): ARLIBS=../libqemu_common.a libqemu.a $(HWLIB)
> +$(QEMU_PROG): ARLIBS=libqemu.a
>  $(QEMU_PROG): $(OBJS) ../libqemu_common.a libqemu.a $(HWLIB)
> -    $(call LINK,$(OBJS))
> +    $(call LINK,$(sort $(OBJS) $(shell $(MAKE) -C .. 
> --no-print-directory libqemu_common.a-OBJS) $(shell $(MAKE) -C $(dir 
> $(HWLIB)) --no-print-directory $(notdir $(HWLIB))-OBJS)))
>

Here, depend on libqemu_common.objlist, and link it by including its 
contents in the link command line.

Oh, we could even make .objlist a linker script, except that's probably 
platform specific.

The real fix is building everything from a single makefile.

-- 
error compiling committee.c: too many arguments to function