FAST_DEPEND: Rework how guessed dependencies are handled.

Rather than depend on .depend not existing, check the actual
.depend.OBJ file that will be used for that object.  If it doesn't
exist then use the guessed dependencies.

FAST_DEPEND may never have a .depend file.  Not having one means all of the
previous logic would over-depend all object files on all headers which is not
what we wanted.  It also means that if a .depend is generated before a build
is done for _EXTRADEPEND (such as for PROG or LIB) then all of these
dependencies would not be used since the .depend wasn't generated from mkdep
and the real .depend.* files are not generated until the build.

Sponsored by:	EMC / Isilon Storage Division

1 files changed, 15 insertions, 5 deletions

diff --git a/sys/conf/kern.post.mk b/sys/conf/kern.post.mk
index a82d904227fc..f1ab570edac1 100644
--- a/sys/conf/kern.post.mk
+++ b/sys/conf/kern.post.mk
@@ -143,8 +143,10 @@ ${FULLKERNEL}: ${SYSTEM_DEP} vers.o
 .endif
 	${SYSTEM_LD_TAIL}
 
-.if !exists(${.OBJDIR}/.depend)
-${SYSTEM_OBJS}: assym.s vnode_if.h ${BEFORE_DEPEND:M*.h} ${MFILES:T:S/.m$/.h/}
+OBJS_DEPEND_GUESS+=	assym.s vnode_if.h ${BEFORE_DEPEND:M*.h} \
+			${MFILES:T:S/.m$/.h/}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/.depend)
+${SYSTEM_OBJS}: ${OBJS_DEPEND_GUESS}
 .endif
 
 LNFILES=	${CFILES:T:S/.c$/.ln/}
@@ -239,10 +241,18 @@ CFLAGS+=	${DEPEND_CFLAGS}
 DEPENDOBJS+=	${SYSTEM_OBJS} genassym.o
 DEPENDFILES_OBJS=	${DEPENDOBJS:O:u:C/^/.depend./}
 .if !defined(_SKIP_READ_DEPEND)
-.for __depend_obj in ${DEPENDFILES_OBJS}
-.sinclude "${__depend_obj}"
-.endfor
+.for __obj in ${DEPENDOBJS}
+.if exists(${.OBJDIR}/.depend.${__obj})
+.include ".depend.${__obj}"
+.else
+# Guess some dependencies for when no .depend.OBJ is generated yet.
+.if ${SYSTEM_OBJS:M${__obj}}
+${__obj}: ${OBJS_DEPEND_GUESS}
 .endif
+${__obj}: ${OBJS_DEPEND_GUESS.${__obj}}
+.endif
+.endfor
+.endif	# !defined(_SKIP_READ_DEPEND)
 .endif	# ${MK_FAST_DEPEND} == "yes"
 
 .NOPATH: .depend ${DEPENDFILES_OBJS}