From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752859AbaHSHet (ORCPT ); Tue, 19 Aug 2014 03:34:49 -0400 Received: from smtp.mei.co.jp ([133.183.100.20]:42627 "EHLO smtp.mei.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752708AbaHSHer (ORCPT ); Tue, 19 Aug 2014 03:34:47 -0400 From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: Masahiro Yamada , Michal Marek , linux-kernel@vger.kernel.org Subject: [PATCH 1/4] kbuild: handle multi-objs dependency appropriately Date: Tue, 19 Aug 2014 16:34:20 +0900 Message-Id: <1408433663-17435-2-git-send-email-yamada.m@jp.panasonic.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1408433663-17435-1-git-send-email-yamada.m@jp.panasonic.com> References: <1408433663-17435-1-git-send-email-yamada.m@jp.panasonic.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 bf3e677..5b09d36 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) $(multi-used-m) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 260bf8a..54be19a 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -159,6 +159,15 @@ dtc_cpp_flags = -Wp,-MD,$(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 -- 1.9.1