Support skipping 'make obj' tree-walk.

This is part of a larger effort for WITH_AUTO_OBJ and a WORLDFAST
option.

Sponsored by:	Dell EMC Isilon

Makefile.inc1

@@ -310,6 +310,13 @@ CLEANDIR=	cleandir
 NO_CLEAN=	t
 .endif
 .endif
+.if defined(NO_OBJ) || ${MK_AUTO_OBJ} == "yes"
+NO_OBJ=		t
+NO_KERNELOBJ=	t
+.endif
+.if !defined(NO_OBJ)
+_obj=		obj
+.endif
 
 LOCAL_TOOL_DIRS?=
 PACKAGEDIR?=	${DESTDIR}/${DISTDIR}
@@ -828,7 +835,11 @@ WMAKE_TGTS+=	_worldtmp _legacy
 .if empty(SUBDIR_OVERRIDE)
 WMAKE_TGTS+=	_bootstrap-tools
 .endif
-WMAKE_TGTS+=	_cleanobj _obj _build-tools _cross-tools
+WMAKE_TGTS+=	_cleanobj
+.if !defined(NO_OBJ)
+WMAKE_TGTS+=	_obj
+.endif
+WMAKE_TGTS+=	_build-tools _cross-tools
 WMAKE_TGTS+=	_compiler-metadata
 WMAKE_TGTS+=	_includes _libraries
 WMAKE_TGTS+=	everything
@@ -1610,7 +1621,7 @@ legacy: .PHONY
 .for _tool in tools/build ${_elftoolchain_libs}
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,includes,all,install)"; \
 	    cd ${.CURDIR}/${_tool}; \
-	    ${MAKE} DIRPRFX=${_tool}/ obj; \
+	    if [ -z "${NO_OBJ}" ]; then ${MAKE} DIRPRFX=${_tool}/ obj; fi; \
 	    ${MAKE} DIRPRFX=${_tool}/ DESTDIR=${MAKEOBJDIRPREFIX}/legacy includes; \
 	    ${MAKE} DIRPRFX=${_tool}/ MK_INCLUDES=no all; \
 	    ${MAKE} DIRPRFX=${_tool}/ MK_INCLUDES=no \
@@ -1766,7 +1777,7 @@ bootstrap-tools: .PHONY
 ${_bt}-${_tool}: .PHONY .MAKE
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,all,install)"; \
 		cd ${.CURDIR}/${_tool}; \
-		${MAKE} DIRPRFX=${_tool}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${MAKE} DIRPRFX=${_tool}/ obj; fi; \
 		${MAKE} DIRPRFX=${_tool}/ all; \
 		${MAKE} DIRPRFX=${_tool}/ DESTDIR=${MAKEOBJDIRPREFIX}/legacy install
 
@@ -1805,7 +1816,7 @@ _rescue=rescue/rescue
 build-tools_${_tool}: .PHONY
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,build-tools)"; \
 		cd ${.CURDIR}/${_tool}; \
-		${MAKE} DIRPRFX=${_tool}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${MAKE} DIRPRFX=${_tool}/ obj; fi; \
 		${MAKE} DIRPRFX=${_tool}/ build-tools
 build-tools: build-tools_${_tool}
 .endfor
@@ -1814,7 +1825,7 @@ build-tools: build-tools_${_tool}
 build-tools_${_tool}: .PHONY
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,all)"; \
 		cd ${.CURDIR}/${_tool}; \
-		${MAKE} DIRPRFX=${_tool}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${MAKE} DIRPRFX=${_tool}/ obj; fi; \
 		${MAKE} DIRPRFX=${_tool}/ all
 build-tools: build-tools_${_tool}
 .endfor
@@ -1899,7 +1910,7 @@ cross-tools: .MAKE .PHONY
     ${_usb_tools}
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,all,install)"; \
 		cd ${.CURDIR}/${_tool}; \
-		${MAKE} DIRPRFX=${_tool}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${MAKE} DIRPRFX=${_tool}/ obj; fi; \
 		${MAKE} DIRPRFX=${_tool}/ all; \
 		${MAKE} DIRPRFX=${_tool}/ DESTDIR=${MAKEOBJDIRPREFIX} install
 .endfor
@@ -1931,7 +1942,7 @@ native-xtools: .PHONY
 	mkdir -p ${OBJTREE}/gperf_for_gcc/usr/bin
 	${_+_}@${ECHODIR} "===> ${_gperf} (obj,all,install)"; \
 	cd ${.CURDIR}/${_gperf}; \
-	${NXBMAKE} DIRPRFX=${_gperf}/ obj; \
+	if [ -z "${NO_OBJ}" ]; then ${NXBMAKE} DIRPRFX=${_gperf}/ obj; fi; \
 	${NXBMAKE} DIRPRFX=${_gperf}/ all; \
 	${NXBMAKE} DIRPRFX=${_gperf}/ DESTDIR=${OBJTREE}/gperf_for_gcc install
 .endif
@@ -2007,7 +2018,7 @@ native-xtools: .PHONY
     usr.sbin/chown
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,all,install)"; \
 		cd ${.CURDIR}/${_tool}; \
-		${NXBMAKE} DIRPRFX=${_tool}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${NXBMAKE} DIRPRFX=${_tool}/ obj; fi; \
 		${NXBMAKE} DIRPRFX=${_tool}/ all; \
 		${NXBMAKE} DIRPRFX=${_tool}/ DESTDIR=${NXBDESTDIR} install
 .endfor
@@ -2269,7 +2280,7 @@ ${_lib}__PL: .PHONY .MAKE
 .if exists(${.CURDIR}/${_lib})
 	${_+_}@${ECHODIR} "===> ${_lib} (obj,all,install)"; \
 		cd ${.CURDIR}/${_lib}; \
-		${MAKE} MK_TESTS=no DIRPRFX=${_lib}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${MAKE} MK_TESTS=no DIRPRFX=${_lib}/ obj; fi; \
 		${MAKE} MK_TESTS=no MK_PROFILE=no -DNO_PIC \
 		    DIRPRFX=${_lib}/ all; \
 		${MAKE} MK_TESTS=no MK_PROFILE=no -DNO_PIC \
@@ -2282,7 +2293,7 @@ ${_lib}__L: .PHONY .MAKE
 .if exists(${.CURDIR}/${_lib})
 	${_+_}@${ECHODIR} "===> ${_lib} (obj,all,install)"; \
 		cd ${.CURDIR}/${_lib}; \
-		${MAKE} MK_TESTS=no DIRPRFX=${_lib}/ obj; \
+		if [ -z "${NO_OBJ}" ]; then ${MAKE} MK_TESTS=no DIRPRFX=${_lib}/ obj; fi; \
 		${MAKE} MK_TESTS=no DIRPRFX=${_lib}/ all; \
 		${MAKE} MK_TESTS=no DIRPRFX=${_lib}/ install
 .endif
@@ -2609,7 +2620,7 @@ _xb-bootstrap-tools: .PHONY
     ${_yacc}
 	${_+_}@${ECHODIR} "===> ${_tool} (obj,all,install)"; \
 	cd ${.CURDIR}/${_tool}; \
-	${CDMAKE} DIRPRFX=${_tool}/ obj; \
+	if [ -z "${NO_OBJ}" ]; then ${CDMAKE} DIRPRFX=${_tool}/ obj; fi; \
 	${CDMAKE} DIRPRFX=${_tool}/ all; \
 	${CDMAKE} DIRPRFX=${_tool}/ DESTDIR=${CDTMP} install
 .endfor
@@ -2628,7 +2639,7 @@ _xb-cross-tools: .PHONY
     ${_gcc}
 	${_+_}@${ECHODIR} "===> xdev ${_tool} (obj,all)"; \
 	cd ${.CURDIR}/${_tool}; \
-	${CDMAKE} DIRPRFX=${_tool}/ obj; \
+	if [ -z "${NO_OBJ}" ]; then ${CDMAKE} DIRPRFX=${_tool}/ obj; fi; \
 	${CDMAKE} DIRPRFX=${_tool}/ all
 .endfor
 

Makefile.libcompat

@@ -163,7 +163,7 @@ build${libcompat}: .PHONY
 .endif
 	mkdir -p ${WORLDTMP}
 	ln -sf ${.CURDIR}/sys ${WORLDTMP}
-.for _t in obj includes
+.for _t in ${_obj} includes
 .for _dir in ${_LC_INCDIRS}
 	${_+_}cd ${.CURDIR}/${_dir}; ${LIBCOMPATWMAKE} MK_INCLUDES=yes \
 	    DIRPRFX=${_dir}/ ${_t}
@@ -180,7 +180,7 @@ build${libcompat}: .PHONY
 	${_+_}cd ${.CURDIR}; \
 	    ${LIBCOMPATWMAKE} -f Makefile.inc1 -DNO_FSCHG libraries
 .if ${libcompat} == "32"
-.for _t in obj all
+.for _t in ${_obj} all
 	${_+_}cd ${.CURDIR}/libexec/rtld-elf; PROG=ld-elf32.so.1 ${LIBCOMPATWMAKE} \
 	    -DNO_FSCHG DIRPRFX=libexec/rtld-elf/ ${_t}
 	${_+_}cd ${.CURDIR}/usr.bin/ldd; PROG=ldd32 ${LIBCOMPATWMAKE} \

share/man/man7/build.7

@@ -605,6 +605,10 @@ If set, the update process does not update the source of the
 documentation as part of the
 .Dq make update
 target.
+.It Va NO_OBJ
+If set, no object directories will be created.
+This should only be used if object directories were created in a
+previous build and no new directories are connected.
 .It Va NO_PORTSUPDATE
 If set, the update process does not update the Ports tree as part of the
 .Dq make update

sys/conf/kern.post.mk

@@ -35,7 +35,7 @@ KERN_DEBUGDIR?=	${DEBUGDIR}
 .MAIN: all
 
 .for target in all clean cleandepend cleandir clobber depend install \
-    obj reinstall tags
+    ${_obj} reinstall tags
 ${target}: kernel-${target}
 .if !defined(MODULES_WITH_WORLD) && !defined(NO_MODULES) && exists($S/modules)
 ${target}: modules-${target}

sys/conf/kern.pre.mk

@@ -24,6 +24,14 @@ _srcconf_included_:
 .MAKE.MODE+=	curdirOk=yes
 .endif
 
+.if defined(NO_OBJ) || ${MK_AUTO_OBJ} == "yes"
+NO_OBJ=		t
+NO_MODULES_OBJ=	t
+.endif
+.if !defined(NO_OBJ)
+_obj=		obj
+.endif
+
 # Can be overridden by makeoptions or /etc/make.conf
 KERNEL_KO?=	kernel
 KERNEL?=	kernel