1 files changed, 127 insertions, 0 deletions
diff --git a/mk/ldorder.mk b/mk/ldorder.mk
new file mode 100644
index 0000000000000..38d9359914aed
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+++ b/mk/ldorder.mk
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+# $Id: ldorder.mk,v 1.18 2018/02/11 18:27:59 sjg Exp $
+#
+#	@(#) Copyright (c) 2015, Simon J. Gerraty
+#
+#	This file is provided in the hope that it will
+#	be of use.  There is absolutely NO WARRANTY.
+#	Permission to copy, redistribute or otherwise
+#	use this file is hereby granted provided that 
+#	the above copyright notice and this notice are
+#	left intact. 
+#      
+#	Please send copies of changes and bug-fixes to:
+#	sjg@crufty.net
+#
+
+# Try to compute optimal link order.
+# When using only shared libs link order does not much matter,
+# but archive libs are a different matter.
+
+# We can construct a graph of .ldorder-lib${LIB*} dependencies
+# and associate each with _LDORDER_USE to output the relevant
+# ld flags.
+# Due to the nature of make, the result will be in the reverse order
+# that we want to feed to ld.
+# So we need to reverse it before use.
+
+.if !target(_LDORDER_USE)
+# does caller want to use ldorder?
+# yes for prog, normally no for lib
+_ldorder_use := ${.ALLTARGETS:Mldorder}
+
+.-include <local.ldorder.mk>
+
+# convert /path/to/libfoo.a into _{LIBFOO}
+LDORDER_INC_FILTER += S,+,PLUS,g S,.so$$,,g
+LDORDER_LIBS_FILTER += O:u
+LDORDER_INC ?= ldorder.inc
+REFERENCE_FILE ?= :
+
+_LDORDER_USE: .ldorder-rm .USE .NOTMAIN
+	@echo depends: ${.ALLSRC:M.ldorder-lib*} > /dev/null
+	@echo ${LDADD_${.TARGET:T:S,.ldorder-,,}:U${.TARGET:T:S/.ldorder-lib/-l/}} >> .ldorder
+	@${META_COOKIE_TOUCH}
+
+# we need to truncate our working file
+.ldorder-rm: .NOTMAIN
+	@rm -f .ldorder ldorder-*
+	@${.ALLSRC:O:u:@f@${REFERENCE_FILE} < $f;@}
+	@${META_COOKIE_TOUCH}
+
+# make sure this exists
+.ldorder:	.NOTMAIN
+
+# and finally we need to reverse the order of content
+ldorder: .ldorder .NOTMAIN
+	@{ test ! -s .ldorder || cat -n .ldorder | sort -rn | \
+	sed '/ldorder-/d;s,^[[:space:]0-9]*,,'; } > ${.TARGET}
+
+# Initially we hook contents of DPLIBS and DPADD into our graph
+LDORDER_LIBS ?= ${DPLIBS} ${DPADD:M*/lib*} ${__dpadd_libs}
+# we need to remember this
+_LDORDER_LIBS := ${LDORDER_LIBS:${LDORDER_LIBS_FILTER:ts:}}
+
+.if empty(_LDORDER_LIBS)
+# don't use stale ldorder
+LDADD_LDORDER =
+.else
+# this is how you use it
+LDADD_LDORDER ?= `cat ldorder`
+.endif
+
+# for debug below
+_ldorder = ${RELDIR}.${TARGET_SPEC}
+
+.endif				# !target(_LDORDER_USE)
+
+.if !empty(LDORDER_LIBS) && !empty(_ldorder_use)
+# canonicalize - these are just tokens anyway
+LDORDER_LIBS := ${LDORDER_LIBS:${LDORDER_LIBS_FILTER:ts:}:R:C/\.so.*//}
+_ldorders := ${LDORDER_LIBS:T:Mlib*:S,^,.ldorder-,}
+
+.for t in ${_ldorders}
+.if !target($t)
+$t: _LDORDER_USE
+.endif
+.endfor
+
+# and this makes it all happen
+.ldorder: ${_ldorders}
+
+# this is how we get the dependencies
+.if ${.INCLUDEDFROMFILE:M*.${LDORDER_INC}} != ""
+_ldorder := .ldorder-${.INCLUDEDFROMFILE:S/.${LDORDER_INC}//}
+${_ldorder}: ${_ldorders}
+.ldorder-rm: ${.INCLUDEDFROMDIR}/${.INCLUDEDFROMFILE}
+.endif
+
+# set DEBUG_LDORDER to pattern[s] that match the dirs of interest
+.if ${DEBUG_LDORDER:Uno:@x@${RELDIR:M$x}@} != ""
+.info ${_ldorder}: ${_ldorders}
+.endif
+
+# now try to find more ...
+# each *.${LDORDER_INC} should set LDORDER_LIBS to what it needs
+# it can also add to CFLAGS etc.
+.for __inc in ${LDORDER_LIBS:S,$,.${LDORDER_INC},}
+.if !target(__${__inc}__)
+__${__inc}__:
+# make sure this is reset
+LDORDER_LIBS =
+.-include <${__inc}>
+.endif
+.endfor
+
+.endif				# !empty(LDORDER_LIBS)
+
+.ifdef LIB
+# you can make this depend on files (must match *ldorder*)
+# to add extra content - like CFLAGS
+libLDORDER_INC = lib${LIB}.${LDORDER_INC}
+.if !commands(${libLDORDER_INC})
+${libLDORDER_INC}:
+	@(cat /dev/null ${.ALLSRC:M*ldorder*}; \
+	echo 'LDORDER_LIBS= ${_LDORDER_LIBS:T:R:${LDORDER_INC_FILTER:ts:}:tu:C,.*,_{&},}'; \
+	echo; echo '.include <ldorder.mk>' ) | sed 's,_{,$${,g' > ${.TARGET}
+.endif
+.endif