Date: Sun, 29 Jul 2001 19:24:49 +0200 From: Sheldon Hearn <sheldonh@starjuice.net> To: hackers@FreeBSD.org Subject: Why objcopy --strip-debug instead of strip? Message-ID: <82186.996427489@axl.seasidesoftware.co.za>
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Hi folks,
When the kernel is built as kernel.debug, why is it passed through
objcopy --strip-debug before being installed, instead of being passed
through strip?
Background: I recently found that the Handbook instructions for
"Debugging Loadable Modules Using GDB" is mostly useless for post-mortem
crash dump analysis, because buildkernel doesn't build modules with
debugging support, even when CONFIGARGS=-g.
The attached patch (for the i386 only) fixes this so that, if kernel.debug
is built, foo.ko.debug etc. are built. For each foo.ko.debug, we
produce foo.ko with objcopy --strip-debug and install foo.ko.
What I'm unsure of is why it's worth going to all this trouble.
Why not simply build all the modules with debugging support compiled in
(assuming debugging support was requested for the kernel), and strip
them at install time (install -s)?
Ciao,
Sheldon.
Index: /usr/src/sys/conf/Makefile.i386
===================================================================
RCS file: /home/ncvs/src/sys/conf/Makefile.i386,v
retrieving revision 1.240
diff -u -d -r1.240 Makefile.i386
--- /usr/src/sys/conf/Makefile.i386 2001/07/26 23:04:46 1.240
+++ /usr/src/sys/conf/Makefile.i386 2001/07/29 16:51:56
@@ -272,6 +272,9 @@
.if defined(MODULES_OVERRIDE)
MKMODULESENV+= MODULES_OVERRIDE="${MODULES_OVERRIDE}"
.endif
+.if defined(DEBUG)
+MKMODULESENV+= DEBUG="${DEBUG}" DEBUG_FLAGS="${DEBUG}"
+.endif
modules:
@mkdir -p ${.OBJDIR}/modules
Index: /usr/src/sys/conf/kmod.mk
===================================================================
RCS file: /home/ncvs/src/sys/conf/kmod.mk,v
retrieving revision 1.104
diff -u -d -r1.104 kmod.mk
--- /usr/src/sys/conf/kmod.mk 2001/07/18 09:59:55 1.104
+++ /usr/src/sys/conf/kmod.mk 2001/07/29 17:15:59
@@ -77,6 +77,7 @@
KMODLOAD?= /sbin/kldload
KMODUNLOAD?= /sbin/kldunload
+OBJCOPY?= objcopy
TARGET_ARCH?= ${MACHINE_ARCH}
@@ -131,7 +132,15 @@
PROG= ${KMOD}.ko
.endif
-${PROG}: ${KMOD}.kld
+.if !defined(DEBUG)
+FULLPROG= ${PROG}
+.else
+FULLPROG= ${PROG}.debug
+${PROG}: ${FULLPROG}
+ ${OBJCOPY} --strip-debug ${FULLPROG} ${PROG}
+.endif
+
+${FULLPROG}: ${KMOD}.kld
${LD} -Bshareable ${LDFLAGS} -o ${.TARGET} ${KMOD}.kld
${KMOD}.kld: ${OBJS}
@@ -188,7 +197,7 @@
${ECHO} ${.TARGET} "->" $$path ; \
ln -s $$path ${.TARGET}
-CLEANFILES+= ${PROG} ${KMOD}.kld ${OBJS} ${_ILINKS} symb.tmp tmp.o
+CLEANFILES+= ${PROG} ${FULLPROG} ${KMOD}.kld ${OBJS} ${_ILINKS} symb.tmp tmp.o
.if !target(install)
.if !target(beforeinstall)
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