It is allowed to add the same objects multiple times to obj-y / obj-m:
obj-y += foo.o foo.o foo.o
obj-m += bar.o bar.o bar.o
It is also allowed to add the same objects multiple times to a composite
module:
obj-m += foo.o
foo-y := foo1.o foo2.o foo2.o foo1.o
This flexibility is useful because the same object might be selected by
different CONFIG options, like this:
obj-m += foo.o
foo-y := foo1.o
foo-$(CONFIG_FOO_X) += foo2.o
foo-$(CONFIG_FOO_Y) += foo2.o
The duplicated objects are omitted at link time. It works naturally in
Makefiles because GNU Make removes duplication in $^ without changing
the order.
It is working well, almost...
A small flaw I notice is, *.mod contains duplication in such a case.
This is probably not a big deal. As far as I know, the only small
problem is scripts/mod/sumversion.c parses the same file multiple
times.
I am fixing this because I plan to reuse *.mod for other purposes,
where the duplication can be problematic.
The code change is quite simple. We already use awk to drop duplicated
lines in modules.order (see cmd_modules_order in the same file).
I copied the code, but changed RS to use spaces as record separators.
I also changed the file format to list one object per line.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Bug: 175420575
(cherry picked from commit 62d88fd6ef3e52c355ec82e1aef530e72cf690e5
https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git kbuild)
Change-Id: Icd83764f7064c7abf4f8bcf9cf784c8c25c52192
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
3fd0696927