subdirmk: Merge new version and fix everything

[secnet.git] / subdirmk / regen.mk.in

diff --git a/subdirmk/regen.mk.in b/subdirmk/regen.mk.in
index f7a72192aa8c31319ffd20ba5164da92e2faf071..d11e05c0a752c1e8a80a93f6cb2ba2db6b611a2c 100644 (file)
--- a/subdirmk/regen.mk.in
+++ b/subdirmk/regen.mk.in
@@ -1,10 +1,38 @@
+# 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
 
-CONFIGURE_ACS  += $(CONFIGURE_AC)
-CONFIGURE_ACS  += subdirmk/subdirmk.ac
+# To turn on debugging here, export SUBDIRMK_REGEN_NDEBUG=''
+SUBDIRMK_REGEN_NDEBUG ?= @
 
 $(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
        cd $(top_srcdir) && autoconf
@@ -12,19 +40,42 @@ $(top_srcdir)/$(CONFIGURE): $(addprefix $(top_srcdir)/,$(CONFIGURE_ACS))
 $(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 $(SUBDIRMK_MAKEFILES) $(CONFIG_STATUS_OUTPUTS): .makefiles.stamp
+       $(SUBDIRMK_REGEN_NDEBUG): REGEN STAMP CAUSES TARGET=$@
 
-main.mk $(MAKEFILES): makefiles.phantom ;
-.INTERMEDIATE: makefiles.phantom
-makefiles.phantom:                                             \
+.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
+realclean:: clean
        $(RM) config.status config.log
-       $(RM) main.mk $(MAKEFILES)
+       $(RM) main.mk $(SUBDIRMK_MAKEFILES) @_SUBDIRMK_MAKEFILES@
+       $(RM) $(addsuffix Makefile,$(dir $(SUBDIRMK_MAKEFILES)))
 
 -include $(ALL_DEPFILES)