| Message ID | 20160807144054.GA14682@ravnborg.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, 7 Aug 2016 16:40:54 +0200 Sam Ravnborg <sam@ravnborg.org> wrote: > On Sun, Aug 07, 2016 at 11:49:46AM +1000, Stephen Rothwell wrote: > > Hi Sam, > > > > On Sat, 6 Aug 2016 22:10:45 +0200 Sam Ravnborg <sam@ravnborg.org> wrote: > > > > > > Did you by any chance evalue the use of INPUT in linker files. > > > Stephen back then (again based on proposal from Alan Modra), > > > also made an implementation using INPUT. > > > > The problem with that idea was that (at least for some versions of > > binutils in use at the time) we hit a static limit to the number of > > object files and ld just stopped at that point. :-( > > The ld bug was caused by opening too many linked definitions files. > We can workaround this by expanding the files. > I gave this a quick spin - see below. > > Note - I have no idea if using thin archived or this method is better. > But it seems just wrong to me that we convert to thin archives when > we really do not need to do so. > > Note - this was a quick spin. It build fine here and thats it. Is there a reason to prefer using linker scripts rather than thin archives? I thought the former was possibly a bit less robust, and the latter a smaller change for scripts and toolchain in terms of "almost behaving like an object file". I don't have a strong preference although do have a couple of (out of tree) scripts that expect objdump to work on built-in.o Thanks, Nick -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Aug 08, 2016 at 01:19:41PM +1000, Nicholas Piggin wrote: > On Sun, 7 Aug 2016 16:40:54 +0200 > Sam Ravnborg <sam@ravnborg.org> wrote: > > > On Sun, Aug 07, 2016 at 11:49:46AM +1000, Stephen Rothwell wrote: > > > Hi Sam, > > > > > > On Sat, 6 Aug 2016 22:10:45 +0200 Sam Ravnborg <sam@ravnborg.org> wrote: > > > > > > > > Did you by any chance evalue the use of INPUT in linker files. > > > > Stephen back then (again based on proposal from Alan Modra), > > > > also made an implementation using INPUT. > > > > > > The problem with that idea was that (at least for some versions of > > > binutils in use at the time) we hit a static limit to the number of > > > object files and ld just stopped at that point. :-( > > > > The ld bug was caused by opening too many linked definitions files. > > We can workaround this by expanding the files. > > I gave this a quick spin - see below. > > > > Note - I have no idea if using thin archived or this method is better. > > But it seems just wrong to me that we convert to thin archives when > > we really do not need to do so. > > > > Note - this was a quick spin. It build fine here and thats it. > > Is there a reason to prefer using linker scripts rather than thin > archives? I thought the former was possibly a bit less robust, and > the latter a smaller change for scripts and toolchain in terms > of "almost behaving like an object file". The only valid reason I can come up with is that it is simpler to build a list of .o files than it is to generate a number of thin archives. I persuaded "linker scripts" mainly because I had the patch floating and I was triggered by the powerpc discussions to resurface it again. > I don't have a strong preference although do have a couple of > (out of tree) scripts that expect objdump to work on built-in.o You are likely not alone here. Unless someone else comes up with any good reason lets stay with thin archives. Sam -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 11602e5..37b8bc9 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -360,10 +360,16 @@ $(sort $(subdir-obj-y)): $(subdir-ym) ; ifdef builtin-target quiet_cmd_link_o_target = LD $@ # If the list of objects to link is empty, just create an empty built-in.o -cmd_link_o_target = $(if $(strip $(obj-y)),\ - $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \ - $(cmd_secanalysis),\ - rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@) +cmd_link_o_target = \ +$(if $(filter $(obj-y), $^), \ + echo $(foreach file, $(filter $(obj-y), $^), \ + $(if $(filter %/built-in.o, $(file)), \ + $(shell cat $(file)), \ + $(file) \ + ) \ + ) \ + , echo "" \ +) > $@ $(builtin-target): $(obj-y) FORCE $(call if_changed,link_o_target) @@ -414,10 +420,10 @@ $($(subst $(obj)/,,$(@:.o=-y))) \ $($(subst $(obj)/,,$(@:.o=-m)))), $^) quiet_cmd_link_multi-y = LD $@ -cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis) +cmd_link_multi-y = echo INPUT\($(link_multi_deps)\) > $@ quiet_cmd_link_multi-m = LD [M] $@ -cmd_link_multi-m = $(cmd_link_multi-y) +cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(multi-used-y): FORCE $(call if_changed,link_multi-y) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index 4f727eb..323c13a 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -41,8 +41,8 @@ info() # ${1} output file modpost_link() { - ${LD} ${LDFLAGS} -r -o ${1} ${KBUILD_VMLINUX_INIT} \ - --start-group ${KBUILD_VMLINUX_MAIN} --end-group + ${LD} ${LDFLAGS} -r -o ${1} ${vmlinux_init} \ + --start-group ${vmlinux_main} --end-group } # Link of vmlinux @@ -54,13 +54,13 @@ vmlinux_link() if [ "${SRCARCH}" != "um" ]; then ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \ - -T ${lds} ${KBUILD_VMLINUX_INIT} \ - --start-group ${KBUILD_VMLINUX_MAIN} --end-group ${1} + -T ${lds} ${vmlinux_init} \ + --start-group ${vmlinux_main} --end-group ${1} else ${CC} ${CFLAGS_vmlinux} -o ${2} \ - -Wl,-T,${lds} ${KBUILD_VMLINUX_INIT} \ + -Wl,-T,${lds} ${vmlinux_init} \ -Wl,--start-group \ - ${KBUILD_VMLINUX_MAIN} \ + ${vmlinux_main} \ -Wl,--end-group \ -lutil -lrt -lpthread ${1} rm -f linux @@ -162,6 +162,23 @@ case "${KCONFIG_CONFIG}" in . "./${KCONFIG_CONFIG}" esac +# Expand built-in.o file as they just list .o files +for f in ${KBUILD_VMLINUX_INIT}; do + if [ $(basename $f) = built-in.o ]; then + vmlinux_init="${vmlinux_init} $(cat $f)" + else + vmlinux_init="${vmlinux_init} $f" + fi +done + +for f in ${KBUILD_VMLINUX_MAIN}; do + if [ $(basename $f) = built-in.o ]; then + vmlinux_main="${vmlinux_main} $(cat $f)" + else + vmlinux_main="${vmlinux_main} $f" + fi +done + #link vmlinux.o info LD vmlinux.o modpost_link vmlinux.o