Leverage dirdeps.mk by tweaking _DIRDEP_USE_LEVEL

so we can have a 2nd stage of dependencies computed in parallel.

Reviewed by: marcel

2 files changed, 88 insertions, 0 deletions

diff --git a/pkgs/pseudo/universe/Makefile b/pkgs/pseudo/universe/Makefile
new file mode 100644
index 000000000000..85b6b7189477
--- /dev/null
+++ b/pkgs/pseudo/universe/Makefile
@@ -0,0 +1,73 @@
+# $FreeBSD$
+
+# This target is "special".
+#
+# The actual work is done via another target;
+# UNIVERSE_TARGET_RELDIR is used to identify it.
+#
+# We leverage dirdeps.mk to run a sub-make per
+# MACHINE/ARCH to each build ${UNIVERSE_TARGET_RELDIR}
+# in meta mode.
+#
+# We simply override the level at which dirdeps.mk normally does
+# its thing, and give it a DIRDEPS list that corresponds to
+# ${UNIVERSE_TARGET_RELDIR}.${TARGET_SPEC} for each TARGET_SPEC we
+# want.
+#
+# This allows the computation of dependencies for each ${TARGET_SPEC}
+# to happen in parallel - avoiding a very long startup time.
+# We can even export each sub-make to a different machine if using a
+# cluster.
+#
+# The above works fine so long as our sub-makes remain independent.
+# That is; none of them  attempts to visit any directory for a machine
+# other than the TARGET_SPEC we gave it.
+# For example; to build some tool for the pseudo machine "host".
+# To avoid that, our Makefile.depend lists all the hosttools we might
+# need and these will thus be built before we launch the
+# ${UNIVERSE_TARGET_RELDIR} sub-makes.
+# Further we add a filter to skip any "host" dirdeps during those
+# sub-makes.
+# 
+# 
+
+# this is the RELDIR of the target we build
+UNIVERSE_TARGET_RELDIR?= pkgs/pseudo/the-lot
+
+# the list of machines
+TARGET_MACHINE_LIST = i386 amd64
+# some machines have more than one arch
+TARGET_ARCHES_arm?=     arm armeb armv6 armv6hf
+
+# avoid ../Makefile.inc defining this
+all:
+
+.include "../Makefile.inc"
+
+.if ${.MAKE.LEVEL} > 0
+# ok our prerequisites have been built
+.if !defined(UNIVERSE_GUARD)
+# just incase we end up back here, 
+# we cannot rely on .MAKE.LEVEL as we normally would
+UNIVERSE_GUARD=1
+.export UNIVERSE_GUARD
+
+# we want to re-use dirdeps
+_DIRDEP_USE_LEVEL = ${.MAKE.LEVEL}
+
+# we want our sub-makes to think they are level 0
+# and we don't want failure of one to stop all.
+DIRDEP_USE_ENV= \
+	MAKELEVEL=0 \
+	MAKE_JOB_ERROR_TOKEN=no
+
+
+_target_specs:= ${TARGET_MACHINE_LIST:@m@${TARGET_ARCHES_$m:U$m:@a@$m,$a@}@:O:u}
+
+DIRDEPS:= ${_target_specs:@t@${UNIVERSE_TARGET_RELDIR}.$t@}
+
+all: dirdeps
+
+.include <dirdeps.mk>
+.endif
+.endif
diff --git a/pkgs/pseudo/universe/Makefile.depend b/pkgs/pseudo/universe/Makefile.depend
new file mode 100644
index 000000000000..e9cbdb58b354
--- /dev/null
+++ b/pkgs/pseudo/universe/Makefile.depend
@@ -0,0 +1,15 @@
+# $FreeBSD$
+
+# This file is not autogenerated - take care!
+
+# this is not normally needed, but we are not normal
+.if ${.MAKE.LEVEL} == 0
+DEP_RELDIR := ${_PARSEDIR:S,${SRCTOP}/,,}
+
+# our role here is to build all the host tools etc.
+DIRDEPS = \
+	pkgs/pseudo/hosttools.host \
+
+
+.include <dirdeps.mk>
+.endif