Add META_MODE support.

Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.

Still need to add real targets under targets/ to build packages.

Differential Revision:       D2796
Reviewed by: brooks imp

1 files changed, 652 insertions, 0 deletions

diff --git a/share/mk/dirdeps.mk b/share/mk/dirdeps.mk
new file mode 100644
index 000000000000..c3c19d22d0a0
--- /dev/null
+++ b/share/mk/dirdeps.mk
@@ -0,0 +1,652 @@
+# $FreeBSD$
+# $Id: dirdeps.mk,v 1.54 2015/06/08 20:55:11 sjg Exp $
+
+# Copyright (c) 2010-2013, Juniper Networks, Inc.
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions 
+# are met: 
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer. 
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.  
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+
+# Much of the complexity here is for supporting cross-building.
+# If a tree does not support that, simply using plain Makefile.depend
+# should provide sufficient clue.
+# Otherwise the recommendation is to use Makefile.depend.${MACHINE}
+# as expected below.
+
+# Note: this file gets multiply included.
+# This is what we do with DIRDEPS
+
+# DIRDEPS:
+#	This is a list of directories - relative to SRCTOP, it is
+#	normally only of interest to .MAKE.LEVEL 0.
+#	In some cases the entry may be qualified with a .<machine>
+#	or .<target_spec> suffix (see TARGET_SPEC_VARS below),
+#	for example to force building something for the pseudo
+#	machines "host" or "common" regardless of current ${MACHINE}.
+#	
+#	All unqualified entries end up being qualified with .${TARGET_SPEC}
+#	and partially qualified (if TARGET_SPEC_VARS has multiple
+#	entries) are also expanded to a full .<target_spec>.
+#	The  _DIRDEP_USE target uses the suffix to set TARGET_SPEC
+#	correctly when visiting each entry.
+#
+#	The fully qualified directory entries are used to construct a
+#	dependency graph that will drive the build later.
+#	
+#	Also, for each fully qualified directory target, we will search
+#	using ${.MAKE.DEPENDFILE_PREFERENCE} to find additional
+#	dependencies.  We use Makefile.depend (default value for
+#	.MAKE.DEPENDFILE_PREFIX) to refer to these makefiles to
+#	distinguish them from others.
+#	
+#	Each Makefile.depend file sets DEP_RELDIR to be the
+#	the RELDIR (path relative to SRCTOP) for its directory, and
+#	since each Makefile.depend file includes dirdeps.mk, this
+#	processing is recursive and results in .MAKE.LEVEL 0 learning the
+#	dependencies of the tree wrt the initial directory (_DEP_RELDIR).
+#
+# BUILD_AT_LEVEL0
+#	Indicates whether .MAKE.LEVEL 0 builds anything:
+#	if "no" sub-makes are used to build everything,
+#	if "yes" sub-makes are only used to build for other machines.
+#	It is best to use "no", but this can require fixing some
+#	makefiles to not do anything at .MAKE.LEVEL 0.
+#
+# TARGET_SPEC_VARS
+#	The default value is just MACHINE, and for most environments
+#	this is sufficient.  The _DIRDEP_USE target actually sets
+#	both MACHINE and TARGET_SPEC to the suffix of the current
+#	target so that in the general case TARGET_SPEC can be ignored.
+#
+#	If more than MACHINE is needed then sys.mk needs to decompose
+#	TARGET_SPEC and set the relevant variables accordingly.
+#	It is important that MACHINE be included in and actually be
+#	the first member of TARGET_SPEC_VARS.  This allows other
+#	variables to be considered optional, and some of the treatment
+#	below relies on MACHINE being the first entry.
+#	Note: TARGET_SPEC cannot contain any '.'s so the target
+#	triple used by compiler folk won't work (directly anyway).
+#
+#	For example:
+#
+#		# Always list MACHINE first, 
+#		# other variables might be optional.
+#		TARGET_SPEC_VARS = MACHINE TARGET_OS
+#		.if ${TARGET_SPEC:Uno:M*,*} != ""
+#		_tspec := ${TARGET_SPEC:S/,/ /g}
+#		MACHINE := ${_tspec:[1]}
+#		TARGET_OS := ${_tspec:[2]}
+#		# etc.
+#		# We need to stop that TARGET_SPEC affecting any submakes
+#		# and deal with MACHINE=${TARGET_SPEC} in the environment.
+#		TARGET_SPEC =
+#		# export but do not track
+#		.export-env TARGET_SPEC 
+#		.export ${TARGET_SPEC_VARS}
+#		.for v in ${TARGET_SPEC_VARS:O:u}
+#		.if empty($v)
+#		.undef $v
+#		.endif
+#		.endfor
+#		.endif
+#		# make sure we know what TARGET_SPEC is
+#		# as we may need it to find Makefile.depend*
+#		TARGET_SPEC = ${TARGET_SPEC_VARS:@v@${$v:U}@:ts,}
+#	
+
+# touch this at your peril
+_DIRDEP_USE_LEVEL?= 0
+.if ${.MAKE.LEVEL} == ${_DIRDEP_USE_LEVEL}
+# only the first instance is interested in all this
+
+# First off, we want to know what ${MACHINE} to build for.
+# This can be complicated if we are using a mixture of ${MACHINE} specific
+# and non-specific Makefile.depend*
+
+.if !target(_DIRDEP_USE)
+# do some setup we only need once
+_CURDIR ?= ${.CURDIR}
+_OBJDIR ?= ${.OBJDIR}
+
+now_utc = ${%s:L:gmtime}
+.if !defined(start_utc)
+start_utc := ${now_utc}
+.endif
+
+# make sure these are empty to start with
+_DEP_TARGET_SPEC =
+_DIRDEP_CHECKED =
+
+# If TARGET_SPEC_VARS is other than just MACHINE
+# it should be set by sys.mk or similar by now.
+# TARGET_SPEC must not contain any '.'s.
+TARGET_SPEC_VARS ?= MACHINE
+# this is what we started with
+TARGET_SPEC = ${TARGET_SPEC_VARS:@v@${$v:U}@:ts,}
+# this is what we mostly use below
+DEP_TARGET_SPEC = ${TARGET_SPEC_VARS:S,^,DEP_,:@v@${$v:U}@:ts,}
+# make sure we have defaults
+.for v in ${TARGET_SPEC_VARS}
+DEP_$v ?= ${$v}
+.endfor
+
+.if ${TARGET_SPEC_VARS:[#]} > 1
+# Ok, this gets more complex (putting it mildly).
+# In order to stay sane, we need to ensure that all the build_dirs
+# we compute below are fully qualified wrt DEP_TARGET_SPEC.
+# The makefiles may only partially specify (eg. MACHINE only),
+# so we need to construct a set of modifiers to fill in the gaps.
+# jot 10 should output 1 2 3 .. 10
+JOT ?= jot
+_tspec_x := ${${JOT} ${TARGET_SPEC_VARS:[#]}:L:sh}
+# this handles unqualified entries
+M_dep_qual_fixes = C;(/[^/.,]+)$$;\1.$${DEP_TARGET_SPEC};
+# there needs to be at least one item missing for these to make sense
+.for i in ${_tspec_x:[2..-1]}
+_tspec_m$i := ${TARGET_SPEC_VARS:[2..$i]:@w@[^,]+@:ts,}
+_tspec_a$i := ,${TARGET_SPEC_VARS:[$i..-1]:@v@$$$${DEP_$v}@:ts,}
+M_dep_qual_fixes += C;(\.${_tspec_m$i})$$;\1${_tspec_a$i};
+.endfor
+.else
+# A harmless? default.
+M_dep_qual_fixes = U
+.endif
+
+.if !defined(.MAKE.DEPENDFILE_PREFERENCE)
+# .MAKE.DEPENDFILE_PREFERENCE makes the logic below neater?
+# you really want this set by sys.mk or similar
+.MAKE.DEPENDFILE_PREFERENCE = ${_CURDIR}/${.MAKE.DEPENDFILE:T}
+.if ${.MAKE.DEPENDFILE:E} == "${TARGET_SPEC}"
+.if ${TARGET_SPEC} != ${MACHINE}
+.MAKE.DEPENDFILE_PREFERENCE += ${_CURDIR}/${.MAKE.DEPENDFILE:T:R}.$${MACHINE}
+.endif
+.MAKE.DEPENDFILE_PREFERENCE += ${_CURDIR}/${.MAKE.DEPENDFILE:T:R}
+.endif
+.endif
+
+_default_dependfile := ${.MAKE.DEPENDFILE_PREFERENCE:[1]:T}
+_machine_dependfiles := ${.MAKE.DEPENDFILE_PREFERENCE:T:M*${MACHINE}*}
+
+# for machine specific dependfiles we require ${MACHINE} to be at the end
+# also for the sake of sanity we require a common prefix
+.if !defined(.MAKE.DEPENDFILE_PREFIX)
+# knowing .MAKE.DEPENDFILE_PREFIX helps
+.if !empty(_machine_dependfiles)
+.MAKE.DEPENDFILE_PREFIX := ${_machine_dependfiles:[1]:T:R}
+.else
+.MAKE.DEPENDFILE_PREFIX := ${_default_dependfile:T}
+.endif
+.endif
+
+
+# this is how we identify non-machine specific dependfiles
+N_notmachine := ${.MAKE.DEPENDFILE_PREFERENCE:E:N*${MACHINE}*:${M_ListToSkip}}
+
+.endif				# !target(_DIRDEP_USE)
+
+# if we were included recursively _DEP_TARGET_SPEC should be valid.
+.if empty(_DEP_TARGET_SPEC)
+# we may or may not have included a dependfile yet
+.if defined(.INCLUDEDFROMFILE)
+_last_dependfile := ${.INCLUDEDFROMFILE:M${.MAKE.DEPENDFILE_PREFIX}*}
+.else
+_last_dependfile := ${.MAKE.MAKEFILES:M*/${.MAKE.DEPENDFILE_PREFIX}*:[-1]}
+.endif
+.if ${_debug_reldir:U0}
+.info ${DEP_RELDIR}.${DEP_TARGET_SPEC}: _last_dependfile='${_last_dependfile}'
+.endif
+
+.if empty(_last_dependfile) || ${_last_dependfile:E:${N_notmachine}} == ""
+# this is all we have to work with
+DEP_MACHINE = ${TARGET_MACHINE:U${MACHINE}}
+_DEP_TARGET_SPEC := ${DEP_TARGET_SPEC}
+.else
+_DEP_TARGET_SPEC = ${_last_dependfile:${M_dep_qual_fixes:ts:}:E}
+.endif
+.if !empty(_last_dependfile)
+# record that we've read dependfile for this
+_DIRDEP_CHECKED += ${_CURDIR}.${TARGET_SPEC}
+.endif
+.endif
+
+# by now _DEP_TARGET_SPEC should be set, parse it.
+.if ${TARGET_SPEC_VARS:[#]} > 1
+# we need to parse DEP_MACHINE may or may not contain more info
+_tspec := ${_DEP_TARGET_SPEC:S/,/ /g}
+.for i in ${_tspec_x}
+DEP_${TARGET_SPEC_VARS:[$i]} := ${_tspec:[$i]}
+.endfor
+.for v in ${TARGET_SPEC_VARS:O:u}
+.if empty(DEP_$v)
+.undef DEP_$v
+.endif
+.endfor
+.else
+DEP_MACHINE := ${_DEP_TARGET_SPEC}
+.endif
+
+# pickup customizations
+# as below you can use !target(_DIRDEP_USE) to protect things
+# which should only be done once.
+.-include "local.dirdeps.mk"
+
+# the first time we are included the _DIRDEP_USE target will not be defined
+# we can use this as a clue to do initialization and other one time things.
+.if !target(_DIRDEP_USE)
+# make sure this target exists
+dirdeps: beforedirdeps .WAIT
+beforedirdeps:
+
+# We normally expect to be included by Makefile.depend.*
+# which sets the DEP_* macros below.
+DEP_RELDIR ?= ${RELDIR}
+
+# this can cause lots of output!
+# set to a set of glob expressions that might match RELDIR
+DEBUG_DIRDEPS ?= no
+
+# remember the initial value of DEP_RELDIR - we test for it below.
+_DEP_RELDIR := ${DEP_RELDIR}
+
+# things we skip for host tools
+SKIP_HOSTDIR ?=
+
+NSkipHostDir = ${SKIP_HOSTDIR:N*.host*:S,$,.host*,:N.host*:S,^,${SRCTOP}/,:${M_ListToSkip}}
+
+# things we always skip
+# SKIP_DIRDEPS allows for adding entries on command line.
+SKIP_DIR += .host *.WAIT ${SKIP_DIRDEPS}
+SKIP_DIR.host += ${SKIP_HOSTDIR}
+
+DEP_SKIP_DIR = ${SKIP_DIR} \
+	${SKIP_DIR.${DEP_TARGET_SPEC}:U} \
+	${SKIP_DIR.${DEP_MACHINE}:U} \
+	${SKIP_DIRDEPS.${DEP_MACHINE}:U}
+
+NSkipDir = ${DEP_SKIP_DIR:${M_ListToSkip}}
+
+.if defined(NO_DIRDEPS) || defined(NODIRDEPS) || defined(WITHOUT_DIRDEPS)
+# confine ourselves to the original dir
+DIRDEPS_FILTER += M${_DEP_RELDIR}*
+.endif
+
+# this is what we run below
+DIRDEP_MAKE?= ${.MAKE}
+
+# we suppress SUBDIR when visiting the leaves
+# we assume sys.mk will set MACHINE_ARCH
+# you can add extras to DIRDEP_USE_ENV
+# if there is no makefile in the target directory, we skip it.
+_DIRDEP_USE:	.USE .MAKE
+	@for m in ${.MAKE.MAKEFILE_PREFERENCE}; do \
+		test -s ${.TARGET:R}/$$m || continue; \
+		echo "${TRACER}Checking ${.TARGET:R} for ${.TARGET:E} ..."; \
+		MACHINE_ARCH= NO_SUBDIR=1 ${DIRDEP_USE_ENV} \
+		TARGET_SPEC=${.TARGET:E} \
+		MACHINE=${.TARGET:E} \
+		${DIRDEP_MAKE} -C ${.TARGET:R} || exit 1; \
+		break; \
+	done
+
+.ifdef ALL_MACHINES
+# this is how you limit it to only the machines we have been built for
+# previously.
+.if empty(ONLY_MACHINE_LIST)
+.if !empty(ALL_MACHINE_LIST)
+# ALL_MACHINE_LIST is the list of all legal machines - ignore anything else
+_machine_list != cd ${_CURDIR} && 'ls' -1 ${ALL_MACHINE_LIST:O:u:@m@${.MAKE.DEPENDFILE:T:R}.$m@} 2> /dev/null; echo
+.else
+_machine_list != 'ls' -1 ${_CURDIR}/${.MAKE.DEPENDFILE_PREFIX}.* 2> /dev/null; echo
+.endif
+_only_machines := ${_machine_list:${NIgnoreFiles:UN*.bak}:E:O:u}
+.else
+_only_machines := ${ONLY_MACHINE_LIST}
+.endif
+
+.if empty(_only_machines)
+# we must be boot-strapping
+_only_machines := ${TARGET_MACHINE:U${ALL_MACHINE_LIST:U${DEP_MACHINE}}}
+.endif
+
+.else				# ! ALL_MACHINES
+# if ONLY_MACHINE_LIST is set, we are limited to that
+# if TARGET_MACHINE is set - it is really the same as ONLY_MACHINE_LIST
+# otherwise DEP_MACHINE is it - so DEP_MACHINE will match.
+_only_machines := ${ONLY_MACHINE_LIST:U${TARGET_MACHINE:U${DEP_MACHINE}}:M${DEP_MACHINE}}
+.endif
+
+.if !empty(NOT_MACHINE_LIST)
+_only_machines := ${_only_machines:${NOT_MACHINE_LIST:${M_ListToSkip}}}
+.endif
+
+# make sure we have a starting place?
+DIRDEPS ?= ${RELDIR}
+.endif				# target 
+
+# if repeatedly building the same target, 
+# we can avoid the overhead of re-computing the tree dependencies.
+MK_DIRDEPS_CACHE ?= no
+BUILD_DIRDEPS_CACHE ?= no
+BUILD_DIRDEPS ?= yes
+
+.if !defined(NO_DIRDEPS)
+.if ${MK_DIRDEPS_CACHE} == "yes"
+# this is where we will cache all our work
+DIRDEPS_CACHE?= ${_OBJDIR}/dirdeps.cache${.TARGETS:Nall:O:u:ts-:S,/,_,g:S,^,.,:N.}
+
+# just ensure this exists
+build-dirdeps:
+
+M_oneperline = @x@\\${.newline}	$$x@
+
+.if ${BUILD_DIRDEPS_CACHE} == "no" 
+.if !target(dirdeps-cached)
+# we do this via sub-make
+BUILD_DIRDEPS = no
+
+dirdeps: dirdeps-cached
+dirdeps-cached:	${DIRDEPS_CACHE} .MAKE
+	@echo "${TRACER}Using ${DIRDEPS_CACHE}"
+	@MAKELEVEL=${.MAKE.LEVEL} ${.MAKE} -C ${_CURDIR} -f ${DIRDEPS_CACHE} \
+		dirdeps MK_DIRDEPS_CACHE=no BUILD_DIRDEPS=no
+
+# these should generally do
+BUILD_DIRDEPS_MAKEFILE ?= ${MAKEFILE}
+BUILD_DIRDEPS_TARGETS ?= ${.TARGETS}
+
+# we need the .meta file to ensure we update if 
+# any of the Makefile.depend* changed.
+# We do not want to compare the command line though.
+${DIRDEPS_CACHE}:	.META .NOMETA_CMP
+	+@{ echo '# Autogenerated - do NOT edit!'; echo; \
+	echo 'BUILD_DIRDEPS=no'; echo; \
+	echo '.include <dirdeps.mk>'; \
+	} > ${.TARGET}.new
+	+@MAKELEVEL=${.MAKE.LEVEL} DIRDEPS_CACHE=${DIRDEPS_CACHE} \
+	DIRDEPS="${DIRDEPS}" \
+	MAKEFLAGS= ${.MAKE} -C ${_CURDIR} -f ${BUILD_DIRDEPS_MAKEFILE} \
+	${BUILD_DIRDEPS_TARGETS} BUILD_DIRDEPS_CACHE=yes \
+	.MAKE.DEPENDFILE=.none \
+	3>&1 1>&2 | sed 's,${SRCTOP},$${SRCTOP},g' >> ${.TARGET}.new && \
+	mv ${.TARGET}.new ${.TARGET}
+
+.endif
+.elif !target(_count_dirdeps)
+# we want to capture the dirdeps count in the cache
+.END: _count_dirdeps
+_count_dirdeps: .NOMETA
+	@echo '.info $${.newline}$${TRACER}Makefiles read: total=${.MAKE.MAKEFILES:[#]} depend=${.MAKE.MAKEFILES:M*depend*:[#]} dirdeps=${.ALLTARGETS:M${SRCTOP}*:O:u:[#]}' >&3
+
+.endif
+.elif !make(dirdeps) && !target(_count_dirdeps)
+beforedirdeps: _count_dirdeps
+_count_dirdeps: .NOMETA
+	@echo "${TRACER}Makefiles read: total=${.MAKE.MAKEFILES:[#]} depend=${.MAKE.MAKEFILES:M*depend*:[#]} dirdeps=${.ALLTARGETS:M${SRCTOP}*:O:u:[#]} seconds=`expr ${now_utc} - ${start_utc}`"
+
+.endif
+.endif
+
+.if ${BUILD_DIRDEPS} == "yes"
+.if ${DEBUG_DIRDEPS:@x@${DEP_RELDIR:M$x}${${DEP_RELDIR}.${DEP_MACHINE}:L:M$x}@} != ""
+_debug_reldir = 1
+.else
+_debug_reldir = 0
+.endif
+.if ${DEBUG_DIRDEPS:@x@${DEP_RELDIR:M$x}${${DEP_RELDIR}.depend:L:M$x}@} != ""
+_debug_search = 1
+.else
+_debug_search = 0
+.endif
+
+# the rest is done repeatedly for every Makefile.depend we read.
+# if we are anything but the original dir we care only about the
+# machine type we were included for..
+
+.if ${DEP_RELDIR} == "."
+_this_dir := ${SRCTOP}
+.else
+_this_dir := ${SRCTOP}/${DEP_RELDIR}
+.endif
+
+# on rare occasions, there can be a need for extra help
+_dep_hack := ${_this_dir}/${.MAKE.DEPENDFILE_PREFIX}.inc
+.-include "${_dep_hack}"
+
+.if ${DEP_RELDIR} != ${_DEP_RELDIR} || ${DEP_TARGET_SPEC} != ${TARGET_SPEC}
+# this should be all
+_machines := ${DEP_MACHINE}
+.else
+# this is the machine list we actually use below
+_machines := ${_only_machines}
+
+.if defined(HOSTPROG) || ${DEP_MACHINE} == "host"
+# we need to build this guy's dependencies for host as well.
+_machines += host
+.endif
+
+_machines := ${_machines:O:u}
+.endif
+
+.if ${TARGET_SPEC_VARS:[#]} > 1
+# we need to tweak _machines
+_dm := ${DEP_MACHINE}
+# apply the same filtering that we do when qualifying DIRDEPS.
+# M_dep_qual_fixes expects .${MACHINE}* so add (and remove) '.'
+_machines := ${_machines:@DEP_MACHINE@${DEP_TARGET_SPEC}@:S,^,.,:${M_dep_qual_fixes:ts:}:O:u:S,^.,,}
+DEP_MACHINE := ${_dm}
+.endif
+
+# reset each time through
+_build_dirs =
+
+.if ${DEP_RELDIR} == ${_DEP_RELDIR}
+# pickup other machines for this dir if necessary
+.if ${BUILD_AT_LEVEL0:Uyes} == "no"
+_build_dirs += ${_machines:@m@${_CURDIR}.$m@}
+.else
+_build_dirs += ${_machines:N${DEP_TARGET_SPEC}:@m@${_CURDIR}.$m@}
+.if ${DEP_TARGET_SPEC} == ${TARGET_SPEC}
+# pickup local dependencies now
+.-include <.depend>
+.endif
+.endif
+.endif
+
+.if ${_debug_reldir}
+.info ${DEP_RELDIR}.${DEP_TARGET_SPEC}: DIRDEPS='${DIRDEPS}'
+.info ${DEP_RELDIR}.${DEP_TARGET_SPEC}: _machines='${_machines}' 
+.endif
+
+.if !empty(DIRDEPS)
+# these we reset each time through as they can depend on DEP_MACHINE
+DEP_DIRDEPS_FILTER = \
+	${DIRDEPS_FILTER.${DEP_TARGET_SPEC}:U} \
+	${DIRDEPS_FILTER.${DEP_MACHINE}:U} \
+	${DIRDEPS_FILTER:U} 
+.if empty(DEP_DIRDEPS_FILTER)
+# something harmless
+DEP_DIRDEPS_FILTER = U
+.endif
+
+# this is what we start with
+__depdirs := ${DIRDEPS:${NSkipDir}:${DEP_DIRDEPS_FILTER:ts:}:C,//+,/,g:O:u:@d@${SRCTOP}/$d@}
+
+# some entries may be qualified with .<machine> 
+# the :M*/*/*.* just tries to limit the dirs we check to likely ones.
+# the ${d:E:M*/*} ensures we don't consider junos/usr.sbin/mgd
+__qual_depdirs := ${__depdirs:M*/*/*.*:@d@${exists($d):?:${"${d:E:M*/*}":?:${exists(${d:R}):?$d:}}}@}
+__unqual_depdirs := ${__depdirs:${__qual_depdirs:Uno:${M_ListToSkip}}}
+
+.if ${DEP_RELDIR} == ${_DEP_RELDIR}
+# if it was called out - we likely need it.
+__hostdpadd := ${DPADD:U.:M${HOST_OBJTOP}/*:S,${HOST_OBJTOP}/,,:H:${NSkipDir}:${DIRDEPS_FILTER:ts:}:S,$,.host,:N.*:@d@${SRCTOP}/$d@}
+__qual_depdirs += ${__hostdpadd}
+.endif
+
+.if ${_debug_reldir}
+.info depdirs=${__depdirs}
+.info qualified=${__qual_depdirs}
+.info unqualified=${__unqual_depdirs}
+.endif
+
+# _build_dirs is what we will feed to _DIRDEP_USE
+_build_dirs += \
+	${__qual_depdirs:M*.host:${NSkipHostDir}:N.host} \
+	${__qual_depdirs:N*.host} \
+	${_machines:Mhost*:@m@${__unqual_depdirs:@d@$d.$m@}@:${NSkipHostDir}:N.host} \
+	${_machines:Nhost*:@m@${__unqual_depdirs:@d@$d.$m@}@}
+
+# qualify everything now
+_build_dirs := ${_build_dirs:${M_dep_qual_fixes:ts:}:O:u}
+
+.endif				# empty DIRDEPS
+
+# Normally if doing make -V something,
+# we do not want to waste time chasing DIRDEPS
+# but if we want to count the number of Makefile.depend* read, we do.
+.if ${.MAKEFLAGS:M-V${_V_READ_DIRDEPS}} == ""
+.if !empty(_build_dirs)
+.if ${BUILD_DIRDEPS_CACHE} == "yes"
+x!= { echo; echo '\# ${DEP_RELDIR}.${DEP_TARGET_SPEC}'; \
+	echo 'dirdeps: ${_build_dirs:${M_oneperline}}'; echo; } >&3; echo
+x!= { ${_build_dirs:@x@${target($x):?:echo '$x: _DIRDEP_USE';}@} echo; } >&3; echo
+.else
+# this makes it all happen
+dirdeps: ${_build_dirs}
+.endif
+${_build_dirs}:	_DIRDEP_USE
+
+.if ${_debug_reldir}
+.info ${DEP_RELDIR}.${DEP_TARGET_SPEC}: needs: ${_build_dirs}
+.endif
+
+# this builds the dependency graph
+.for m in ${_machines}
+# it would be nice to do :N${.TARGET}
+.if !empty(__qual_depdirs)
+.for q in ${__qual_depdirs:${M_dep_qual_fixes:ts:}:E:O:u:N$m}
+.if ${_debug_reldir} || ${DEBUG_DIRDEPS:@x@${${DEP_RELDIR}.$m:L:M$x}${${DEP_RELDIR}.$q:L:M$x}@} != ""
+.info ${DEP_RELDIR}.$m: graph: ${_build_dirs:M*.$q}
+.endif
+.if ${BUILD_DIRDEPS_CACHE} == "yes"
+x!= { echo; echo '${_this_dir}.$m: ${_build_dirs:M*.$q:${M_oneperline}}'; echo; } >&3; echo
+.else
+${_this_dir}.$m: ${_build_dirs:M*.$q}
+.endif
+.endfor
+.endif
+.if ${_debug_reldir}
+.info ${DEP_RELDIR}.$m: graph: ${_build_dirs:M*.$m:N${_this_dir}.$m}
+.endif
+.if ${BUILD_DIRDEPS_CACHE} == "yes"
+x!= { echo; echo '${_this_dir}.$m: ${_build_dirs:M*.$m:N${_this_dir}.$m:${M_oneperline}}'; echo; } >&3; echo
+.else
+${_this_dir}.$m: ${_build_dirs:M*.$m:N${_this_dir}.$m}
+.endif
+.endfor
+
+.endif
+
+# Now find more dependencies - and recurse.
+.for d in ${_build_dirs}
+.if ${_DIRDEP_CHECKED:M$d} == ""
+# once only
+_DIRDEP_CHECKED += $d
+.if ${_debug_search}
+.info checking $d
+.endif
+# Note: _build_dirs is fully qualifed so d:R is always the directory
+.if exists(${d:R})
+# Warning: there is an assumption here that MACHINE is always 
+# the first entry in TARGET_SPEC_VARS.
+# If TARGET_SPEC and MACHINE are insufficient, you have a problem.
+_m := ${.MAKE.DEPENDFILE_PREFERENCE:T:S;${TARGET_SPEC}$;${d:E};:S;${MACHINE};${d:E:C/,.*//};:@m@${exists(${d:R}/$m):?${d:R}/$m:}@:[1]}
+.if !empty(_m)
+# M_dep_qual_fixes isn't geared to Makefile.depend
+_qm := ${_m:C;(\.depend)$;\1.${d:E};:${M_dep_qual_fixes:ts:}}
+.if ${_debug_search}
+.info Looking for ${_qm}
+.endif
+# we pass _DEP_TARGET_SPEC to tell the next step what we want
+_DEP_TARGET_SPEC := ${d:E}
+# some makefiles may still look at this
+_DEP_MACHINE := ${d:E:C/,.*//}
+# set this "just in case" 
+# we can skip :tA since we computed the path above
+DEP_RELDIR := ${_m:H:S,${SRCTOP}/,,}
+# and reset this
+DIRDEPS =
+.if ${_debug_reldir} && ${_qm} != ${_m}
+.info loading ${_m} for ${d:E}
+.endif
+.include <${_m}>
+.endif
+.endif
+.endif
+.endfor
+
+.endif				# -V
+.endif				# BUILD_DIRDEPS
+
+.elif ${.MAKE.LEVEL} > 42
+.error You should have stopped recursing by now.
+.else
+# we are building something
+DEP_RELDIR := ${RELDIR}
+_DEP_RELDIR := ${RELDIR}
+# pickup local dependencies
+.-include <.depend>
+.endif
+
+# bootstrapping new dependencies made easy?
+.if (make(bootstrap) || make(bootstrap-recurse)) && !target(bootstrap)
+
+.if exists(${.CURDIR}/${.MAKE.DEPENDFILE:T})
+# stop here
+${.TARGETS:Mboot*}:
+.else
+# find a Makefile.depend to use as _src
+_src != cd ${.CURDIR} && for m in ${.MAKE.DEPENDFILE_PREFERENCE:T:S,${MACHINE},*,}; do test -s $$m || continue; echo $$m; break; done; echo
+.if empty(_src)
+.error cannot find any of ${.MAKE.DEPENDFILE_PREFERENCE:T}
+.endif
+
+_src?= ${.MAKE.DEPENDFILE:T}
+
+bootstrap-this:	.NOTMAIN
+	@echo Bootstrapping ${RELDIR}/${.MAKE.DEPENDFILE:T} from ${_src:T}
+	(cd ${.CURDIR} && sed 's,${_src:E},${MACHINE},g' ${_src} > ${.MAKE.DEPENDFILE:T})
+
+bootstrap: bootstrap-recurse
+bootstrap-recurse: bootstrap-this
+
+_mf := ${.PARSEFILE}
+bootstrap-recurse:	.NOTMAIN .MAKE
+	@cd ${SRCTOP} && \
+	for d in `cd ${RELDIR} && ${.MAKE} -B -f ${"${.MAKEFLAGS:M-n}":?${_src}:${.MAKE.DEPENDFILE:T}} -V DIRDEPS`; do \
+		test -d $$d || d=$${d%.*}; \
+		test -d $$d || continue; \
+		echo "Checking $$d for bootstrap ..."; \
+		(cd $$d && ${.MAKE} -f ${_mf} bootstrap-recurse); \
+	done
+
+.endif
+.endif