+# subdirmk - rules for regenerating makefiles etc.
+# Copyright 2019 Mark Wooding
+# Copyright 2019 Ian Jackson
+# SPDX-License-Identifier: LGPL-2.0-or-later
+# There is NO WARRANTY.
+
+# Usage:
+# include subdirmk/regen.mk
+# (probably in toplevel Dir.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.
+#
+# Makefiles updated by config.status and passed to SUBDIRMK_MAKEFILES
+# in configure.ac are automatically handled too. If you have other
+# files updated by config.status (eg, the output of autoheader) you
+# need to put them in CONFIG_STATUS_OUTPUTS (before your inclusion
+# of regen.mk).
+#
+# Also provides a `realclean::' target at the toplevel which deletes
+# the autoconf output. (This is suitable for being part of a recursive
+# target creaed by setting &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 += $(CONFIGURE_AC)
+CONFIGURE_ACS += subdirmk/subdirmk.ac
+
+# To turn on debugging here, export SUBDIRMK_REGEN_NDEBUG=''
+SUBDIRMK_REGEN_NDEBUG ?= @
-$(top_srcdir)/$(CONFIGURE): $(top_srcdir)/$(CONFIGURE_AC)
- cd &^ && autoconf
+$(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
+ cd $(top_srcdir) && autoconf
$(CONFIG_STATUS): $(top_srcdir)/$(CONFIGURE)
./$(CONFIG_STATUS) --recheck
-MAKEFILES += subdirmk/regen.mk
+# generate will add all its own inputs and outputs to these variables
+SUBDIRMK_MAKEFILES += @_SUBDIRMK_MAKEFILES@
+MAKEFILE_TEMPLATES += $(addprefix $(top_srcdir)/, $(addsuffix .in, \
+ @_SUBDIRMK_MAKEFILES@ \
+ ))
-main.mk $(MAKFILES): makefiles.phantom
-.INTERMEDIATE: makefiles.phantom
-makefiles.phantom: \
+main.mk $(SUBDIRMK_MAKEFILES) $(CONFIG_STATUS_OUTPUTS): .makefiles.stamp
+ $(SUBDIRMK_REGEN_NDEBUG): REGEN STAMP CAUSES TARGET=$@
+
+.makefiles.stamp: \
$(top_srcdir)/subdirmk/generate \
$(CONFIG_STATUS) \
- $(top_srcdir)/Perdir.mk.in \
- $(foreach m,$(MAKEFILES),$(top_srcdir)/$(m).in)
- ./$(CONFIG_STATUS)
+ $(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 (Dir.sd.mk, Final.sd.mk and *.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 Dir.sd.mk twice because if $(top_srcdir) is `.', make
+# elides the directory part from $?. Similarly but not identically
+# Final.sd.mk.
+ $(SUBDIRMK_REGEN_NDEBUG): REGEN STAMP WANTS DEPS=$?
+ ./$(CONFIG_STATUS) $(if \
+ $(filter-out Dir.sd.mk %/Dir.sd.mk \
+ Final.sd.mk $(top_srcdir)/Final.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_MAKEFILES) @_SUBDIRMK_MAKEFILES@
+ $(RM) $(addsuffix Makefile,$(dir $(SUBDIRMK_MAKEFILES)))
+
+-include $(ALL_DEPFILES)