Re: [PATCH v3 2/8] lib: collect library files in an archive

[Jan Beulich <jbeulich@xxxxxxxx>]

On 10.12.2020 15:47, Anthony PERARD wrote:
> On Mon, Nov 23, 2020 at 04:21:19PM +0100, Jan Beulich wrote:
>> --- a/xen/Rules.mk
>> +++ b/xen/Rules.mk
>> @@ -60,7 +64,14 @@ include Makefile
>>  # 
>> ---------------------------------------------------------------------------
>>  
>>  quiet_cmd_ld = LD      $@
>> -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs)
>> +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \
>> +               --start-group $(filter %.a,$(real-prereqs)) --end-group
> 
> It might be a bit weird to modify the generic LD command for the benefit
> of only prelink.o objects but it's probably fine as long as we only use
> archives for lib.a. libelf and libfdt will just have --start/end-group
> added to there ld command line. So I guess the change is fine.

I'm afraid I don't understand what the concern is. Neither libelf
nor libfdt use any %.a right now. Or are you referring to them
merely because it's just them which have got converted to using
$(call if-changed ...), and your remark would eventually apply to
e.g. built_in.o as well? And then further is all you're worried
about the fact that there may be "--start-group  --end-group" on
the command line, i.e. with nothing inbetween? If so, besides
possibly looking a little odd if someone inspected the command
lines closely, what possible issue do you see? (If there is one,
making the addition of both options conditional upon there being
any/multiple %.a in the first place wouldn't be a big problem,
albeit Linux also doesn't care whether ${KBUILD_VMLINUX_LIBS} is
empty.)

> The rest looks good,
> Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

Thanks, but I'd prefer the above clarified.

Jan