kbuild: macrofy the condition of if_changed and friends
Add a new macro that expands into $(newer-prereqs)$(cmd-check).
It makes it easier to add common code for if_changed, if_changed_dep,
and if_changed_rule.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index f247e69..c3c975a 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -130,13 +130,15 @@
# PHONY targets skipped in both cases.
newer-prereqs = $(filter-out $(PHONY),$?)
+if-changed-cond = $(newer-prereqs)$(cmd-check)
+
# Execute command if command has changed or prerequisite(s) are updated.
-if_changed = $(if $(newer-prereqs)$(cmd-check), \
+if_changed = $(if $(if-changed-cond), \
$(cmd); \
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
# Execute the command and also postprocess generated .d dependencies file.
-if_changed_dep = $(if $(newer-prereqs)$(cmd-check),$(cmd_and_fixdep),@:)
+if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
cmd_and_fixdep = \
$(cmd); \
@@ -146,7 +148,7 @@
# Usage: $(call if_changed_rule,foo)
# Will check if $(cmd_foo) or any of the prerequisites changed,
# and if so will execute $(rule_foo).
-if_changed_rule = $(if $(newer-prereqs)$(cmd-check),$(rule_$(1)),@:)
+if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:)
###
# why - tell why a target got built