On Fri, Apr 8, 2022 at 2:55 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > On Wed, Apr 6, 2022 at 8:31 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > > > 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-objs := 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). > > Why does the top level Makefile reassign cmd_modules_order rather than > use the original value in scripts/Makefile.build? Because the top level Makefile does not include scripts/Makefile.build > > 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@xxxxxxxxxx> > > --- > > > > scripts/Makefile.build | 3 ++- > > scripts/mod/sumversion.c | 2 +- > > 2 files changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > > index 6ae92d119dfa..f7a30f378e20 100644 > > --- a/scripts/Makefile.build > > +++ b/scripts/Makefile.build > > @@ -303,7 +303,8 @@ $(obj)/%.prelink.o: $(obj)/%.o FORCE > > $(call if_changed,cc_prelink_modules) > > endif > > > > -cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) > $@ > > +cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ > > + $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ > > God AWK is unreadable. Any reason we can't use GNU make's sort builtin? > https://www.gnu.org/software/make/manual/html_node/Text-Functions.html I did that in the previous submission. https://lore.kernel.org/lkml/20220405113359.2880241-8-masahiroy@xxxxxxxxxx/ After some thoughts, I decided to drop duplicates without sorting. If I alphabetically sorted the object list, 7/7 of this series would be impossible. I am not a big fan of AWK, but I do not know a cleaner way. If you know a better idea, please tell me. -- Best Regards Masahiro Yamada
