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authorMasahiro Yamada <masahiroy@kernel.org>2022-04-07 00:30:21 +0900
committerMasahiro Yamada <masahiroy@kernel.org>2022-05-08 03:16:59 +0900
commit22f26f21774f838e97921952d8c5c4aab3da2ea4 (patch)
tree9c0444b901b5b7a65a2cad0d5a60ae00c17b33cd /scripts/Makefile.build
parent9413e7640564fe70b24ea1a9ff3fb92c5bb52fcb (diff)
kbuild: get rid of duplication in *.mod files
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>
Diffstat (limited to 'scripts/Makefile.build')
-rw-r--r--scripts/Makefile.build3
1 files changed, 2 insertions, 1 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)