From c8589d1e9e01debdb4f574afe7c585714353ad79 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.m@jp.panasonic.com>
Date: Tue, 19 Aug 2014 16:34:20 +0900
Subject: [PATCH] kbuild: handle multi-objs dependency appropriately
The comment in scripts/Makefile.build says as follows:
We would rather have a list of rules like
foo.o: $(foo-objs)
but that's not so easy, so we rather make all composite objects depend
on the set of all their parts
This commit makes it possible!
For example, assume a Makefile like this
obj-m = foo.o bar.o
foo-objs := foo1.o foo2.o
bar-objs := bar1.o bar2.o
Without this patch, foo.o depends on all of
foo1.o foo2.o bar1.o bar2.o.
It looks funny that foo.o is regenerated when bar1.c is updated.
Now we can handle the dependency of foo.o and bar.o separately.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
---
scripts/Makefile.build | 10 ++++------
scripts/Makefile.lib | 9 +++++++++
2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index bf3e6778cd71..5b09d3637855 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -382,16 +382,14 @@ cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalys
quiet_cmd_link_multi-m = LD [M] $@
cmd_link_multi-m = $(cmd_link_multi-y)
-# We would rather have a list of rules like
-# foo.o: $(foo-objs)
-# but that's not so easy, so we rather make all composite objects depend
-# on the set of all their parts
-$(multi-used-y) : %.o: $(multi-objs-y) FORCE
+$(multi-used-y): FORCE
$(call if_changed,link_multi-y)
+$(call multi_depend, $(multi-used-y), .o, -objs -y)
-$(multi-used-m) : %.o: $(multi-objs-m) FORCE
+$(multi-used-m): FORCE
$(call if_changed,link_multi-m)
@{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
+$(call multi_depend, $(multi-used-m), .o, -objs -y)
targets += $(multi-used-y) $(multi-used-m)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 260bf8acfce9..54be19a0fa51 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -159,6 +159,15 @@ dtc_cpp_flags = -Wp,-MD,$(depfile).pre.tmp -nostdinc \
modname-multi = $(sort $(foreach m,$(multi-used),\
$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))
+# Useful for describing the dependency of composite objects
+# Usage:
+# $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)
+define multi_depend
+$(foreach m, $(notdir $1), \
+ $(eval $(obj)/$m: \
+ $(addprefix $(obj)/, $(foreach s, $3, $($(m:%$(strip $2)=%$(s)))))))
+endef
+
ifdef REGENERATE_PARSERS
# GPERF
--
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