Re: [Xen-devel] [XEN PATCH v2 02/12] xen/build: Use obj-y += subdir/ instead of subdir-y

[Jan Beulich <jbeulich@xxxxxxxx>]

On 30.01.2020 17:54, Anthony PERARD wrote:
> On Wed, Jan 29, 2020 at 03:19:05PM +0100, Jan Beulich wrote:
>> On 17.01.2020 11:53, Anthony PERARD wrote:
>>> +# Handle objects in subdirs
>>> +# 
>>> ---------------------------------------------------------------------------
>>> +# o if we encounter foo/ in $(obj-y), replace it by foo/built_in.o
>>> +#   and add the directory to the list of dirs to descend into: $(subdir-y)
>>> +__subdir-y := $(filter %/, $(obj-y))
>>> +subdir-y   += $(__subdir-y)
>>
>> I realize I'll be called guilty of bike-shedding again, and I also
>> realize this is the way Linux does it, but what use is the
>> intermediate __subdir-y? Linux has no 2nd use, and hence I also
>> don't see why we would gain one. I further think according to our
>> style there should be no use of tabs here.
> 
> I though the extra __subdir-y that Linux does was to do the filtering on
> obj-y right way and not at a later time when subdir-y is used. But in
> Linux (now that I look more closely at it), subdir-y is initialised with
> := to have the right type, so the extra __subdir-y doesn't appear to be
> useful. (And I didn't find any subdir-y=)
> 
> So, I'll add a "subdir-y :=" somewhere and remove the need for
> __subdir-y. (And hopefully, no one will add a subdir-y=dir somewhere and
> break the build.)

Alternatively, to retain this "latching" effect, how about

subdir-y := $(subdir-y) $(filter %/, $(obj-y))

?

Jan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel