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).
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]++' > $@
$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE
$(call if_changed,mod)
diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index 0125698f2037..79bb9eaa65ac 100644
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -398,7 +398,7 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
buf = read_text_file(filelist);
md4_init(&md);
- while ((fname = strsep(&buf, " \n"))) {
+ while ((fname = strsep(&buf, "\n"))) {
if (!*fname)
continue;
if (!(is_static_library(fname)) &&
--
2.32.0
