kconfig: refactor Makefile to reduce process forks

Refactor Makefile and use read-file macro. For Make >= 4.2, it can read
out a file by using the built-in function.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

1 files changed, 24 insertions, 21 deletions

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index b8ef0fb4bbef..0b1d15efaeb0 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -159,11 +159,12 @@ conf-objs	:= conf.o $(common-objs)
 hostprogs	+= nconf
 nconf-objs	:= nconf.o nconf.gui.o $(common-objs)
 
-HOSTLDLIBS_nconf	= $(shell . $(obj)/nconf-cfg && echo $$libs)
-HOSTCFLAGS_nconf.o	= $(shell . $(obj)/nconf-cfg && echo $$cflags)
-HOSTCFLAGS_nconf.gui.o	= $(shell . $(obj)/nconf-cfg && echo $$cflags)
+HOSTLDLIBS_nconf       = $(call read-file, $(obj)/nconf-libs)
+HOSTCFLAGS_nconf.o     = $(call read-file, $(obj)/nconf-cflags)
+HOSTCFLAGS_nconf.gui.o = $(call read-file, $(obj)/nconf-cflags)
 
-$(obj)/nconf.o $(obj)/nconf.gui.o: $(obj)/nconf-cfg
+$(obj)/nconf: | $(obj)/nconf-libs
+$(obj)/nconf.o $(obj)/nconf.gui.o: | $(obj)/nconf-cflags
 
 # mconf: Used for the menuconfig target based on lxdialog
 hostprogs	+= mconf
@@ -171,27 +172,28 @@ lxdialog	:= $(addprefix lxdialog/, \
 		     checklist.o inputbox.o menubox.o textbox.o util.o yesno.o)
 mconf-objs	:= mconf.o $(lxdialog) $(common-objs)
 
-HOSTLDLIBS_mconf = $(shell . $(obj)/mconf-cfg && echo $$libs)
+HOSTLDLIBS_mconf = $(call read-file, $(obj)/mconf-libs)
 $(foreach f, mconf.o $(lxdialog), \
-  $(eval HOSTCFLAGS_$f = $$(shell . $(obj)/mconf-cfg && echo $$$$cflags)))
+  $(eval HOSTCFLAGS_$f = $$(call read-file, $(obj)/mconf-cflags)))
 
-$(addprefix $(obj)/, mconf.o $(lxdialog)): $(obj)/mconf-cfg
+$(obj)/mconf: | $(obj)/mconf-libs
+$(addprefix $(obj)/, mconf.o $(lxdialog)): | $(obj)/mconf-cflags
 
 # qconf: Used for the xconfig target based on Qt
 hostprogs	+= qconf
 qconf-cxxobjs	:= qconf.o qconf-moc.o
 qconf-objs	:= images.o $(common-objs)
 
-HOSTLDLIBS_qconf	= $(shell . $(obj)/qconf-cfg && echo $$libs)
-HOSTCXXFLAGS_qconf.o	= $(shell . $(obj)/qconf-cfg && echo $$cflags)
-HOSTCXXFLAGS_qconf-moc.o = $(shell . $(obj)/qconf-cfg && echo $$cflags)
-
-$(obj)/qconf.o: $(obj)/qconf-cfg
+HOSTLDLIBS_qconf         = $(call read-file, $(obj)/qconf-libs)
+HOSTCXXFLAGS_qconf.o     = -std=c++11 -fPIC $(call read-file, $(obj)/qconf-cflags)
+HOSTCXXFLAGS_qconf-moc.o = -std=c++11 -fPIC $(call read-file, $(obj)/qconf-cflags)
+$(obj)/qconf: | $(obj)/qconf-libs
+$(obj)/qconf.o $(obj)/qconf-moc.o: | $(obj)/qconf-cflags
 
 quiet_cmd_moc = MOC     $@
-      cmd_moc = $(shell . $(obj)/qconf-cfg && echo $$moc) $< -o $@
+      cmd_moc = $(call read-file, $(obj)/qconf-bin)/moc $< -o $@
 
-$(obj)/qconf-moc.cc: $(src)/qconf.h $(obj)/qconf-cfg FORCE
+$(obj)/qconf-moc.cc: $(src)/qconf.h FORCE | $(obj)/qconf-bin
 	$(call if_changed,moc)
 
 targets += qconf-moc.cc
@@ -200,15 +202,16 @@ targets += qconf-moc.cc
 hostprogs	+= gconf
 gconf-objs	:= gconf.o images.o $(common-objs)
 
-HOSTLDLIBS_gconf    = $(shell . $(obj)/gconf-cfg && echo $$libs)
-HOSTCFLAGS_gconf.o  = $(shell . $(obj)/gconf-cfg && echo $$cflags)
+HOSTLDLIBS_gconf   = $(call read-file, $(obj)/gconf-libs)
+HOSTCFLAGS_gconf.o = $(call read-file, $(obj)/gconf-cflags)
 
-$(obj)/gconf.o: $(obj)/gconf-cfg
+$(obj)/gconf: | $(obj)/gconf-libs
+$(obj)/gconf.o: | $(obj)/gconf-cflags
 
 # check if necessary packages are available, and configure build flags
-filechk_conf_cfg = $(CONFIG_SHELL) $<
+cmd_conf_cfg = $< $(addprefix $(obj)/$*conf-, cflags libs bin)
 
-$(obj)/%conf-cfg: $(src)/%conf-cfg.sh FORCE
-	$(call filechk,conf_cfg)
+$(obj)/%conf-cflags $(obj)/%conf-libs $(obj)/%conf-bin: $(src)/%conf-cfg.sh
+	$(call cmd,conf_cfg)
 
-clean-files += *conf-cfg
+clean-files += *conf-cflags *conf-libs *conf-bin