Re: [Qemu-devel] [RFC PATCH 0/4] per-object libraries

[Paolo Bonzini <pbonzini@redhat.com>]

Il 19/06/2013 20:18, Michael Tokarev ha scritto:
> Currently I expand it like this:
> 
>   $(foreach m, $(filter %.o,$1), $($(m:%.o=%.libs)))
> 
> Probably I can change that to
> 
>   $(foreach m, $(filter %.o,$1), $($(m:%.o=./%.libs)))
> 
> (here and in other similar cases), and it will work without changing
> anything around $(obj).
> 
> But maybe we can argee here that this is not really OBJect, it is
> a path or dir, and name it $(d) or $(p) instead of $(obj) ?  To
> include the slash when needed. just like I did for $(obj).

I chose $(obj) because that's what Kbuild uses.

>> > Also, for the inevitable bikeshedding, I would prefer
>> > 
>> >    cflags-$(obj)/curl.o-y
>> >    libs-$(obj)/curl.o-y
> What are all these -y suffixes for?  In existing variables and in
> this new your invention?  It's already a bit too verbose.

It is so that you can do

foo-$(CONFIG_XYZ) += blah

instead of

ifeq ($(CONFIG_XYZ),y)
FOO += blah
endif

> BTW, can you take a look why your expand-nesting does not remove
> the save- variables properly?  Run make with -p and see which
> vars are defined.  (This is really BTW, you just reminded me
> about something I've seen but had no chance to look at).

Because I didn't bother. :)

>> common.o: $(patsubst %,../%, $(common-obj-y))
>> 	$(LD) -r -o $@ $^
>>
>> and then link common.o into the QEMU target.

I think that would make it a bit more complex to gather all the required
libs.  But it is probably not insurmountable.

>> >        Libtool can also be used
>> > to abstract "ld -r".  Making libtool mandatory wouldn't be a problem IMO
>> > (we'd need it anyway for modules) as long as you do not need libtool to
>> > start QEMU or gdb from the build directory.
> Do we really need it for modules?  I'm not sure.  Actually, in a modern
> world, I'm not really sure libtool is needed if you only count "major"
> operating systems.

Do you also count one major proprietary operating system?  Unfortunately
mingw still requires magic to create shared libraries.

Paolo