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

5 files changed, 62 insertions, 33 deletions

diff --git a/share/mk/bsd.dep.mk b/share/mk/bsd.dep.mk
index 2c4acd2..ec2ac1f 100644
--- a/share/mk/bsd.dep.mk
+++ b/share/mk/bsd.dep.mk
@@ -94,19 +94,21 @@ _SKIP_READ_DEPEND=	1
 .if defined(SRCS)
 CLEANFILES?=
 
-.if ${MK_FAST_DEPEND} == "yes" || !exists(${.OBJDIR}/${DEPENDFILE})
 .for _S in ${SRCS:N*.[dhly]}
-${_S:R}.o: ${_S}
-.endfor
+OBJS_DEPEND_GUESS.${_S:R}.o=	${_S}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${_S:R}.o: ${OBJS_DEPEND_GUESS.${_S:R}.o}
 .endif
+.endfor
 
 # Lexical analyzers
 .for _LSRC in ${SRCS:M*.l:N*/*}
 .for _LC in ${_LSRC:R}.c
 ${_LC}: ${_LSRC}
 	${LEX} ${LFLAGS} -o${.TARGET} ${.ALLSRC}
-.if ${MK_FAST_DEPEND} == "yes" || !exists(${.OBJDIR}/${DEPENDFILE})
-${_LC:R}.o: ${_LC}
+OBJS_DEPEND_GUESS.${_LC:R}.o=	${_LC}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${_LC:R}.o: ${OBJS_DEPEND_GUESS.${_LC:R}.o}
 .endif
 SRCS:=	${SRCS:S/${_LSRC}/${_LC}/}
 CLEANFILES+= ${_LC}
@@ -136,8 +138,9 @@ CLEANFILES+= ${_YH}
 ${_YC}: ${_YSRC}
 	${YACC} ${YFLAGS} -o ${_YC} ${.ALLSRC}
 .endif
-.if ${MK_FAST_DEPEND} == "yes" || !exists(${.OBJDIR}/${DEPENDFILE})
-${_YC:R}.o: ${_YC}
+OBJS_DEPEND_GUESS.${_YC:R}.o=	${_YC}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${_YC:R}.o: ${OBJS_DEPEND_GUESS.${_YC:R}.o}
 .endif
 .endfor
 .endfor
@@ -195,7 +198,7 @@ DEPENDFILES_OBJS=	${DEPENDOBJS:O:u:${DEPEND_FILTER}:C/^/${DEPENDFILE}./}
 .for __depend_obj in ${DEPENDFILES_OBJS}
 .sinclude "${__depend_obj}"
 .endfor
-.endif
+.endif	# !defined(_SKIP_READ_DEPEND)
 .endif	# ${MK_FAST_DEPEND} == "yes"
 .endif	# defined(SRCS)
 
@@ -208,6 +211,18 @@ beforedepend:
 afterdepend: beforedepend
 .endif
 
+# Guess some dependencies for when no ${DEPENDFILE}.OBJ is generated yet.
+# Done here to support meta mode as well which does not always need
+# the CFLAGS modifications or .depend.* included.
+.if ${MK_FAST_DEPEND} == "yes"
+.for __obj in ${DEPENDOBJS:O:u}
+.if !exists(${.OBJDIR}/${DEPENDFILE}.${__obj})
+${__obj}: ${OBJS_DEPEND_GUESS}
+${__obj}: ${OBJS_DEPEND_GUESS.${__obj}}
+.endif
+.endfor
+.endif
+
 .if !target(depend)
 .if defined(SRCS)
 depend: beforedepend ${DEPENDFILE} afterdepend
diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
index dc81c1c..036d3d1 100644
--- a/share/mk/bsd.lib.mk
+++ b/share/mk/bsd.lib.mk
@@ -415,28 +415,31 @@ lint: ${SRCS:M*.c}
 .include <bsd.man.mk>
 .endif
 
-.include <bsd.dep.mk>
-
-.if ${MK_FAST_DEPEND} == "yes" || !exists(${.OBJDIR}/${DEPENDFILE})
 .if defined(LIB) && !empty(LIB)
-.if !exists(${.OBJDIR}/${DEPENDFILE})
-${OBJS} ${STATICOBJS} ${POBJS}: ${SRCS:M*.h}
+OBJS_DEPEND_GUESS+= ${SRCS:M*.h}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${OBJS} ${STATICOBJS} ${POBJS}: ${OBJS_DEPEND_GUESS}
 .endif
 .for _S in ${SRCS:N*.[hly]}
-${_S:R}.po: ${_S}
+OBJS_DEPEND_GUESS.${_S:R}.po=	${_S}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${_S:R}.po: ${OBJS_DEPEND_GUESS.${_S:R}.po}
+.endif
 .endfor
 .endif
 .if defined(SHLIB_NAME) || \
     defined(INSTALL_PIC_ARCHIVE) && defined(LIB) && !empty(LIB)
-.if !exists(${.OBJDIR}/${DEPENDFILE})
-${SOBJS}: ${SRCS:M*.h}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${SOBJS}: ${OBJS_DEPEND_GUESS}
 .endif
 .for _S in ${SRCS:N*.[hly]}
-${_S:R}.So: ${_S}
-.endfor
+OBJS_DEPEND_GUESS.${_S:R}.So=	${_S}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${_S:R}.So: ${OBJS_DEPEND_GUESS.${_S:R}.So}
 .endif
+.endfor
 .endif
 
+.include <bsd.dep.mk>
 .include <bsd.obj.mk>
-
 .include <bsd.sys.mk>
diff --git a/share/mk/bsd.prog.mk b/share/mk/bsd.prog.mk
index 612eb8e..ec5dec9 100644
--- a/share/mk/bsd.prog.mk
+++ b/share/mk/bsd.prog.mk
@@ -275,12 +275,13 @@ lint: ${SRCS:M*.c}
 .include <bsd.man.mk>
 .endif
 
-.include <bsd.dep.mk>
-
-.if defined(PROG) && !exists(${.OBJDIR}/${DEPENDFILE})
-${OBJS}: ${SRCS:M*.h}
+.if defined(PROG)
+OBJS_DEPEND_GUESS+= ${SRCS:M*.h}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${OBJS}: ${OBJS_DEPEND_GUESS}
+.endif
 .endif
 
+.include <bsd.dep.mk>
 .include <bsd.obj.mk>
-
 .include <bsd.sys.mk>
diff --git a/sys/conf/kern.post.mk b/sys/conf/kern.post.mk
index a82d904..f1ab570 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}
diff --git a/sys/conf/kmod.mk b/sys/conf/kmod.mk
index 3f8cd6b..2cd6ada 100644
--- a/sys/conf/kmod.mk
+++ b/sys/conf/kmod.mk
@@ -450,16 +450,16 @@ lint: ${SRCS}
 ${OBJS}: opt_global.h
 .endif
 
-.include <bsd.dep.mk>
-
 CLEANDEPENDFILES+=	${_ILINKS}
 # .depend needs include links so we remove them only together.
 cleanilinks:
 	rm -f ${_ILINKS}
 
-.if !exists(${.OBJDIR}/${DEPENDFILE})
-${OBJS}: ${SRCS:M*.h}
+OBJS_DEPEND_GUESS+= ${SRCS:M*.h}
+.if ${MK_FAST_DEPEND} == "no" && !exists(${.OBJDIR}/${DEPENDFILE})
+${OBJS}: ${OBJS_DEPEND_GUESS}
 .endif
 
+.include <bsd.dep.mk>
 .include <bsd.obj.mk>
 .include "kern.mk"