+# subdirmk - rules for regenerating makefiles etc.
+# Copyright 2019 Mark Wooding
+# Copyright 2019 Ian Jackson
+# SPDX-License-Identifier: LGPL-2.0-or-later
+
+# Usage:
+# include subdirmk/regen.mk
+# (probably in toplevel Subdir.sd.mk)
+#
+# Arranges that config.status is automatically rerun to update
+# makefiles from templates, whenever a template *.sd.mk or *.mk.in is
+# edited; and that autoconf is rerun if configure's inputs are edited.
+#
+# If you add includes to configure.ac, add them to CONFIGURE_ACS.
+#
+# Also provides a `realclean::' target at the toplevel which deletes
+# the autoconf output. This may be made into a recursive target
+# by mentioning &TARGETS_realclean in appropriate .sd.mk.
CONFIGURE ?= configure
-CONFIGURE_AC ?= $(CONFIGURE).ac
-CONFIG_STATUS ?= config.status
+CONFIGURE_AC ?= $(CONFIGURE).ac
+CONFIG_STATUS ?= config.status
-CONFIGURE_ACS += $(CONFIGURE_AC)
-CONFIGURE_ACS += subdirmk/subdirmk.ac
+CONFIGURE_ACS += $(CONFIGURE_AC)
+CONFIGURE_ACS += subdirmk/subdirmk.ac
$(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
cd $(top_srcdir) && autoconf
$(CONFIG_STATUS): $(top_srcdir)/$(CONFIGURE)
./$(CONFIG_STATUS) --recheck
-MAKEFILES += subdirmk/regen.mk
+# Normally, generate will add all the inputs to MAKEFILE_TEMPLATES.
+MAKEFILE_TEMPLATES += $(addprefix $(top_srcdir)/, $(addsuffix .in, \
+ @_SUBDIRMK_MAKEFILES@ \
+ ))
-main.mk $(MAKEFILES): .config.status.needed
- ./$<
-.INTERMEDIATE: .config.status.needed
-.config.status.needed: \
+main.mk $(MAKEFILES): .makefiles.stamp ;
+.makefiles.stamp: \
$(top_srcdir)/subdirmk/generate \
$(CONFIG_STATUS) \
- $(top_srcdir)/Perdir.mk.in \
- $(foreach m,$(MAKEFILES),$(top_srcdir)/$(m).in)
- : $?
- set -e; printf >$@.tmp "#!/bin/sh\nset -e\n%s %s" \
- "./$(CONFIG_STATUS)" \
- "$(if $(filter-out %.mk.in, $?),, \
- $(patsubst %.mk.in,%.mk,$?))" ; \
- chmod +x $@.tmp; mv -f $@.tmp $@
+ $(MAKEFILE_TEMPLATES)
+# This filtering arranges that we can often run config.status to
+# generate only particular output files. We look for *inputs* that
+# have changed. If the only inputs that have changed are ones that we
+# know affect only one output (Subdir.mk.in and regen.mk.in), we pass
+# config.status the corresponding output file names. Otherwise we
+# pass nothing and config.status does them all. We need to mention
+# regen.mk.in twice because if $(top_srcdir) is `.', make elides the
+# directory part from $?.
+ ./$(CONFIG_STATUS) $(if \
+ $(filter-out Subdir.sd.mk %/Subdir.sd.mk \
+ %.mk.in \
+ , $?),, \
+ $(patsubst $(top_srcdir)/%,%, $(sort \
+ $(patsubst %.sd.mk,%.mk,$(filter %.sd.mk,$?)) \
+ $(patsubst %.mk.in,%.mk,$(filter %.mk.in,$?)))))
+ touch $@
realclean:: clean
$(RM) config.status config.log
- $(RM) main.mk subdirmk/regen.mk $(MAKEFILES)
+ $(RM) main.mk $(MAKEFILES) @_SUBDIRMK_MAKEFILES@
$(RM) $(addsuffix Makefile,$(dir $(MAKEFILES)))
-include $(ALL_DEPFILES)