WITH_CTF can now be specified in src.conf (not recommended, there

are some problems with static executables), make.conf (would also
affect ports which do not use GNU make and do not override the
compile targets) or in the kernel config (via "makeoptions
WITH_CTF=yes").

Additional (related) changes:
 - propagate WITH_CTF to module builds
 - do not add -g to the linker flags, it's a noop there anyway
   (at least according to the man page of ld)
 - do not add -g to CFLAGS unconditionally
   we need to have a look if it is really needed (IMO not) or if there
   is a way to add it only when WITH_CTF is used

Note: ctfconvert / ctfmerge lines will not appear in the build output,
to protect the innocent (those which do not build with WITH_CTF would
see the shell-test and may think WITH_CTF is used).

Reviewed by:	imp, jhb, scottl (earlier version)
Discussed on:	arch@

10 files changed, 92 insertions, 118 deletions

diff --git a/UPDATING b/UPDATING
index fd8a611..553e961 100644
--- a/UPDATING
+++ b/UPDATING
@@ -22,6 +22,16 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 9.x IS SLOW:
 	machines to maximize performance.  (To disable malloc debugging, run
 	ln -s aj /etc/malloc.conf.)
 
+20100402:
+	WITH_CTF can now be specified in src.conf (not recommended, there
+	are some problems with static executables), make.conf (would also
+	affect ports which do not use GNU make and do not override the
+	compile targets) or in the kernel config (via "makeoptions
+	WITH_CTF=yes").
+	When WITH_CTF was specified there before this was silently ignored,
+	so make sure that WITH_CTF is not used in places which could lead
+	to unwanted behavior.
+
 20100311:
 	The kernel option COMPAT_IA32 has been replaced with COMPAT_FREEBSD32
 	to allow 32-bit compatibility on non-x86 platforms. All kernel
diff --git a/share/man/man7/build.7 b/share/man/man7/build.7
index 3015776..67a2445 100644
--- a/share/man/man7/build.7
+++ b/share/man/man7/build.7
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 31, 2010
+.Dd April 02, 2010
 .Dt BUILD 7
 .Os
 .Sh NAME
@@ -341,6 +341,15 @@ or the command line.
 .It Va NO_WERROR
 If defined, compiler warnings will not cause the build to halt,
 even if the makefile says otherwise.
+.It Va WITH_CTF
+If defined, the build process will run the DTrace CTF conversion
+tools on built objects.
+Please note that this WITH_ option is handled differently than all
+other WITH_ options (there is no
+.Va WITHOUT_CTF ,
+or corresponding
+.Va MK_CTF
+in the build system).
 .El
 .Pp
 Additionally, builds in
diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
index 470d9d4..67a09d7 100644
--- a/share/mk/bsd.lib.mk
+++ b/share/mk/bsd.lib.mk
@@ -33,6 +33,11 @@ CFLAGS+= -DNDEBUG
 NO_WERROR=
 .endif
 
+# Enable CTF conversion on request.
+.if defined(WITH_CTF)
+.undef NO_CTF
+.endif
+
 .if defined(DEBUG_FLAGS)
 CFLAGS+= ${DEBUG_FLAGS}
 
@@ -68,15 +73,11 @@ PO_FLAG=-pg
 
 .c.po:
 	${CC} ${PO_FLAG} ${PO_CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .c.So:
 	${CC} ${PICFLAG} -DPIC ${CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .cc.po .C.po .cpp.po .cxx.po:
 	${CXX} ${PO_FLAG} ${PO_CXXFLAGS} -c ${.IMPSRC} -o ${.TARGET}
@@ -86,58 +87,40 @@ PO_FLAG=-pg
 
 .f.po:
 	${FC} -pg ${FFLAGS} -o ${.TARGET} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .f.So:
 	${FC} ${PICFLAG} -DPIC ${FFLAGS} -o ${.TARGET} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .m.po:
 	${OBJC} ${OBJCFLAGS} -pg -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .m.So:
 	${OBJC} ${PICFLAG} -DPIC ${OBJCFLAGS} -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .s.po .s.So:
 	${AS} ${AFLAGS} -o ${.TARGET} ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .asm.po:
 	${CC} -x assembler-with-cpp -DPROF ${PO_CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .asm.So:
 	${CC} -x assembler-with-cpp ${PICFLAG} -DPIC ${CFLAGS} \
 	    -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .S.po:
 	${CC} -DPROF ${PO_CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .S.So:
 	${CC} ${PICFLAG} -DPIC ${CFLAGS} -c ${.IMPSRC} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 all: objwarn
 
@@ -208,9 +191,7 @@ ${SHLIB_NAME}: ${SOBJS}
 	    -o ${.TARGET} -Wl,-soname,${SONAME} \
 	    `NM='${NM}' lorder ${SOBJS} | tsort -q` ${LDADD}
 .endif
-.if defined(CTFMERGE)
-	${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${SOBJS}
-.endif
+	@[ -z "${CTFMERGE}" -o -n "${NO_CTF}" ] || ${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${SOBJS}
 .endif
 
 .if defined(INSTALL_PIC_ARCHIVE) && defined(LIB) && !empty(LIB) && ${MK_TOOLCHAIN} != "no"
diff --git a/share/mk/bsd.port.mk b/share/mk/bsd.port.mk
index 99374a5..87e4935 100644
--- a/share/mk/bsd.port.mk
+++ b/share/mk/bsd.port.mk
@@ -7,5 +7,10 @@ BSDPORTMK?=	${PORTSDIR}/Mk/bsd.port.mk
 # and setting MK_* variables when building ports.
 _WITHOUT_SRCCONF=
 
+# Enable CTF conversion on request.
+.if defined(WITH_CTF)
+.undef NO_CTF
+.endif
+
 .include <bsd.own.mk>
 .include "${BSDPORTMK}"
diff --git a/share/mk/bsd.prog.mk b/share/mk/bsd.prog.mk
index 4de78cb..810a83b 100644
--- a/share/mk/bsd.prog.mk
+++ b/share/mk/bsd.prog.mk
@@ -15,6 +15,11 @@ CFLAGS+= -DNDEBUG
 NO_WERROR=
 .endif
 
+# Enable CTF conversion on request.
+.if defined(WITH_CTF)
+.undef NO_CTF
+.endif
+
 .if defined(DEBUG_FLAGS)
 CFLAGS+=${DEBUG_FLAGS}
 CXXFLAGS+=${DEBUG_FLAGS}
@@ -61,9 +66,7 @@ ${PROG}: ${OBJS}
 .else
 	${CC} ${CFLAGS} ${LDFLAGS} -o ${.TARGET} ${OBJS} ${LDADD}
 .endif
-.if defined(CTFMERGE)
-	${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${OBJS}
-.endif
+	@[ -z "${CTFMERGE}" -o -n "${NO_CTF}" ] || ${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${OBJS}
 
 .else	# !defined(SRCS)
 
@@ -87,9 +90,7 @@ ${PROG}: ${OBJS}
 .else
 	${CC} ${CFLAGS} ${LDFLAGS} -o ${.TARGET} ${OBJS} ${LDADD}
 .endif
-.if defined(CTFMERGE)
-	${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${OBJS}
-.endif
+	@[ -z "${CTFMERGE}" -o -n "${NO_CTF}" ] || ${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${OBJS}
 .endif
 
 .endif
diff --git a/share/mk/sys.mk b/share/mk/sys.mk
index 51ec039..80ad3fa 100644
--- a/share/mk/sys.mk
+++ b/share/mk/sys.mk
@@ -55,14 +55,14 @@ NO_CTF		=	1
 # C Type Format data is required for DTrace
 CTFFLAGS	?=	-L VERSION
 
-.if !defined(NO_CTF)
 CTFCONVERT	?=	ctfconvert
 CTFMERGE	?=	ctfmerge
 .if defined(CFLAGS) && (${CFLAGS:M-g} != "")
 CTFFLAGS	+=	-g
 .else
-CFLAGS		+=	-g
-.endif
+# XXX: What to do here? Is removing the CFLAGS part completely ok here?
+# For now comment it out to not compile with -g unconditionally.
+#CFLAGS		+=	-g
 .endif
 
 CXX		?=	c++
@@ -144,15 +144,11 @@ YFLAGS		?=	-d
 # SINGLE SUFFIX RULES
 .c:
 	${CC} ${CFLAGS} ${LDFLAGS} -o ${.TARGET} ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .f:
 	${FC} ${FFLAGS} ${LDFLAGS} -o ${.TARGET} ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .sh:
 	cp ${.IMPSRC} ${.TARGET}
@@ -162,33 +158,25 @@ YFLAGS		?=	-d
 
 .c.o:
 	${CC} ${CFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .f.o:
 	${FC} ${FFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .y.o:
 	${YACC} ${YFLAGS} ${.IMPSRC}
 	${CC} ${CFLAGS} -c y.tab.c
 	rm -f y.tab.c
 	mv y.tab.o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .l.o:
 	${LEX} ${LFLAGS} ${.IMPSRC}
 	${CC} ${CFLAGS} -c lex.yy.c
 	rm -f lex.yy.c
 	mv lex.yy.o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .y.c:
 	${YACC} ${YFLAGS} ${.IMPSRC}
@@ -226,15 +214,11 @@ YFLAGS		?=	-d
 
 .c:
 	${CC} ${CFLAGS} ${LDFLAGS} ${.IMPSRC} ${LDLIBS} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .c.o:
 	${CC} ${CFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .cc .cpp .cxx .C:
 	${CXX} ${CXXFLAGS} ${LDFLAGS} ${.IMPSRC} ${LDLIBS} -o ${.TARGET}
@@ -244,15 +228,11 @@ YFLAGS		?=	-d
 
 .m.o:
 	${OBJC} ${OBJCFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .p.o:
 	${PC} ${PFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .e .r .F .f:
 	${FC} ${RFLAGS} ${EFLAGS} ${FFLAGS} ${LDFLAGS} ${.IMPSRC} ${LDLIBS} \
@@ -263,38 +243,28 @@ YFLAGS		?=	-d
 
 .S.o:
 	${CC} ${CFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .asm.o:
 	${CC} -x assembler-with-cpp ${CFLAGS} -c ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .s.o:
 	${AS} ${AFLAGS} -o ${.TARGET} ${.IMPSRC}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 # XXX not -j safe
 .y.o:
 	${YACC} ${YFLAGS} ${.IMPSRC}
 	${CC} ${CFLAGS} -c y.tab.c -o ${.TARGET}
 	rm -f y.tab.c
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .l.o:
 	${LEX} -t ${LFLAGS} ${.IMPSRC} > ${.PREFIX}.tmp.c
 	${CC} ${CFLAGS} -c ${.PREFIX}.tmp.c -o ${.TARGET}
 	rm -f ${.PREFIX}.tmp.c
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 # XXX not -j safe
 .y.c:
@@ -306,34 +276,26 @@ YFLAGS		?=	-d
 
 .s.out .c.out .o.out:
 	${CC} ${CFLAGS} ${LDFLAGS} ${.IMPSRC} ${LDLIBS} -o ${.TARGET}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .f.out .F.out .r.out .e.out:
 	${FC} ${EFLAGS} ${RFLAGS} ${FFLAGS} ${LDFLAGS} ${.IMPSRC} \
 	    ${LDLIBS} -o ${.TARGET}
 	rm -f ${.PREFIX}.o
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 # XXX not -j safe
 .y.out:
 	${YACC} ${YFLAGS} ${.IMPSRC}
 	${CC} ${CFLAGS} ${LDFLAGS} y.tab.c ${LDLIBS} -ly -o ${.TARGET}
 	rm -f y.tab.c
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 .l.out:
 	${LEX} -t ${LFLAGS} ${.IMPSRC} > ${.PREFIX}.tmp.c
 	${CC} ${CFLAGS} ${LDFLAGS} ${.PREFIX}.tmp.c ${LDLIBS} -ll -o ${.TARGET}
 	rm -f ${.PREFIX}.tmp.c
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 # FreeBSD build pollution.  Hide it in the non-POSIX part of the ifdef.
 __MAKE_CONF?=/etc/make.conf
diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk
index 0f5cd66..7e23a80 100644
--- a/sys/conf/kern.mk
+++ b/sys/conf/kern.mk
@@ -108,3 +108,11 @@ CFLAGS+=	-restrict
 	${MACHINE_ARCH} != "arm" && ${MACHINE_ARCH} != "mips"
 CFLAGS+=	-fstack-protector
 .endif
+
+#
+# Enable CTF conversation on request.
+#
+.if defined(WITH_CTF)
+.undef NO_CTF
+.endif
+
diff --git a/sys/conf/kern.post.mk b/sys/conf/kern.post.mk
index f808c95..c5c9c34 100644
--- a/sys/conf/kern.post.mk
+++ b/sys/conf/kern.post.mk
@@ -19,6 +19,10 @@ MKMODULESENV+=	KERNBUILDDIR="${.CURDIR}" SYSDIR="${SYSDIR}"
 MKMODULESENV+=	CONF_CFLAGS="${CONF_CFLAGS}"
 .endif
 
+.if defined(WITH_CTF)
+MKMODULESENV+=	WITH_CTF="${WITH_CTF}"
+.endif
+
 .MAIN: all
 
 .for target in all clean cleandepend cleandir clobber depend install \
@@ -90,9 +94,7 @@ ${FULLKERNEL}: ${SYSTEM_DEP} vers.o
 	@rm -f ${.TARGET}
 	@echo linking ${.TARGET}
 	${SYSTEM_LD}
-.if defined(CTFMERGE)
-	${SYSTEM_CTFMERGE}
-.endif
+	@${SYSTEM_CTFMERGE}
 .if !defined(DEBUG)
 	${OBJCOPY} --strip-debug ${.TARGET}
 .endif
@@ -240,9 +242,7 @@ kernel-reinstall:
 
 config.o env.o hints.o vers.o vnode_if.o:
 	${NORMAL_C}
-.if defined(CTFCONVERT)
-	${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.endif
+	@[ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 config.ln env.ln hints.ln vers.ln vnode_if.ln:
 	${NORMAL_LINT}
diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index ee74a9e..39a045a 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -128,11 +128,7 @@ NORMAL_C_NOWERROR= ${CC} -c ${CFLAGS} ${PROF} ${.IMPSRC}
 NORMAL_M= ${AWK} -f $S/tools/makeobjops.awk ${.IMPSRC} -c ; \
 	  ${CC} -c ${CFLAGS} ${WERROR} ${PROF} ${.PREFIX}.c
 
-.if defined(CTFCONVERT)
-NORMAL_CTFCONVERT= ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
-.else
-NORMAL_CTFCONVERT=
-.endif
+NORMAL_CTFCONVERT= [ -z "${CTFCONVERT}" -o -n "${NO_CTF}" ] || ${CTFCONVERT} ${CTFFLAGS} ${.TARGET}
 
 NORMAL_LINT=	${LINT} ${LINTFLAGS} ${CFLAGS:M-[DIU]*} ${.IMPSRC}
 
@@ -142,10 +138,7 @@ SYSTEM_DEP= Makefile ${SYSTEM_OBJS}
 SYSTEM_OBJS= locore.o ${MDOBJS} ${OBJS}
 SYSTEM_OBJS+= ${SYSTEM_CFILES:.c=.o}
 SYSTEM_OBJS+= hack.So
-.if defined(CTFMERGE)
-SYSTEM_CTFMERGE= ${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${SYSTEM_OBJS} vers.o
-LD+= -g
-.endif
+SYSTEM_CTFMERGE= [ -z "${CTFMERGE}" -o -n "${NO_CTF}" ] || ${CTFMERGE} ${CTFFLAGS} -o ${.TARGET} ${SYSTEM_OBJS} vers.o
 SYSTEM_LD= @${LD} -Bdynamic -T ${LDSCRIPT} \
 	-warn-common -export-dynamic -dynamic-linker /red/herring \
 	-o ${.TARGET} -X ${SYSTEM_OBJS} vers.o
diff --git a/sys/conf/kmod.mk b/sys/conf/kmod.mk
index 2cd7509..526eec7 100644
--- a/sys/conf/kmod.mk
+++ b/sys/conf/kmod.mk
@@ -69,6 +69,11 @@ OBJCOPY?=	objcopy
 .error "Do not use KMODDEPS on 5.0+; use MODULE_VERSION/MODULE_DEPEND"
 .endif
 
+# Enable CTF conversion on request.
+.if defined(WITH_CTF)
+.undef NO_CTF
+.endif
+
 .include <bsd.init.mk>
 
 .SUFFIXES: .out .o .c .cc .cxx .C .y .l .s .S