| Message ID | 21714b83-8619-5aa9-be5b-3015d05a26a4@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xen: beginnings of moving library-like code into an archive | expand |
Hi, > On 23 Nov 2020, at 15:21, Jan Beulich <jbeulich@suse.com> wrote: > > In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT > just to avoid bloating binaries when only some arch-es and/or > configurations need generic library routines, combine objects under lib/ > into an archive, which the linker then can pick the necessary objects > out of. > > Note that we can't use thin archives just yet, until we've raised the > minimum required binutils version suitably. > > Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> with one remark... > --- > xen/Rules.mk | 29 +++++++++++++++++++++++++---- > xen/arch/arm/Makefile | 6 +++--- > xen/arch/x86/Makefile | 8 ++++---- > xen/lib/Makefile | 3 ++- > 4 files changed, 34 insertions(+), 12 deletions(-) > > diff --git a/xen/Rules.mk b/xen/Rules.mk > index d5e5eb33de39..aba6ca2a90f5 100644 > --- a/xen/Rules.mk > +++ b/xen/Rules.mk > @@ -41,12 +41,16 @@ ALL_OBJS-y += $(BASEDIR)/xsm/built_in.o > ALL_OBJS-y += $(BASEDIR)/arch/$(TARGET_ARCH)/built_in.o > ALL_OBJS-$(CONFIG_CRYPTO) += $(BASEDIR)/crypto/built_in.o > > +ALL_LIBS-y := $(BASEDIR)/lib/lib.a > + > # Initialise some variables > +lib-y := > targets := > CFLAGS-y := > AFLAGS-y := > > ALL_OBJS := $(ALL_OBJS-y) > +ALL_LIBS := $(ALL_LIBS-y) > > SPECIAL_DATA_SECTIONS := rodata $(foreach a,1 2 4 8 16, \ > $(foreach w,1 2 4, \ > @@ -60,7 +64,14 @@ include Makefile > # --------------------------------------------------------------------------- > > quiet_cmd_ld = LD $@ > -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) > +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ > + --start-group $(filter %.a,$(real-prereqs)) --end-group This might be a good idea to add a comment to explain why the start/end-group is needed so that someone does not change this back in the future. Something like: put libraries between start/end group to have unused symbols removed. Cheers Bertrand > + > +# Archive > +# --------------------------------------------------------------------------- > + > +quiet_cmd_ar = AR $@ > +cmd_ar = rm -f $@; $(AR) cPrs $@ $(real-prereqs) > > # Objcopy > # --------------------------------------------------------------------------- > @@ -86,6 +97,10 @@ obj-y := $(patsubst %/, %/built_in.o, $(obj-y)) > # tell kbuild to descend > subdir-obj-y := $(filter %/built_in.o, $(obj-y)) > > +# Libraries are always collected in one lib file. > +# Filter out objects already built-in > +lib-y := $(filter-out $(obj-y), $(sort $(lib-y))) > + > $(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): CFLAGS-y += -DINIT_SECTIONS_ONLY > > ifeq ($(CONFIG_COVERAGE),y) > @@ -129,7 +144,7 @@ include $(BASEDIR)/arch/$(TARGET_ARCH)/Rules.mk > c_flags += $(CFLAGS-y) > a_flags += $(CFLAGS-y) $(AFLAGS-y) > > -built_in.o: $(obj-y) $(extra-y) > +built_in.o: $(obj-y) $(if $(strip $(lib-y)),lib.a) $(extra-y) > ifeq ($(strip $(obj-y)),) > $(CC) $(c_flags) -c -x c /dev/null -o $@ > else > @@ -140,8 +155,14 @@ else > endif > endif > > +lib.a: $(lib-y) FORCE > + $(call if_changed,ar) > + > targets += built_in.o > -targets += $(filter-out $(subdir-obj-y), $(obj-y)) $(extra-y) > +ifneq ($(strip $(lib-y)),) > +targets += lib.a > +endif > +targets += $(filter-out $(subdir-obj-y), $(obj-y) $(lib-y)) $(extra-y) > targets += $(MAKECMDGOALS) > > built_in_bin.o: $(obj-bin-y) $(extra-y) > @@ -155,7 +176,7 @@ endif > PHONY += FORCE > FORCE: > > -%/built_in.o: FORCE > +%/built_in.o %/lib.a: FORCE > $(MAKE) -f $(BASEDIR)/Rules.mk -C $* built_in.o > > %/built_in_bin.o: FORCE > diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile > index 296c5e68bbc3..612a83b315c8 100644 > --- a/xen/arch/arm/Makefile > +++ b/xen/arch/arm/Makefile > @@ -90,14 +90,14 @@ endif > > ifeq ($(CONFIG_LTO),y) > # Gather all LTO objects together > -prelink_lto.o: $(ALL_OBJS) > - $(LD_LTO) -r -o $@ $^ > +prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS) > + $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group > > # Link it with all the binary objects > prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o > $(call if_changed,ld) > else > -prelink.o: $(ALL_OBJS) FORCE > +prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE > $(call if_changed,ld) > endif > > diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile > index 9b368632fb43..8f2180485b2b 100644 > --- a/xen/arch/x86/Makefile > +++ b/xen/arch/x86/Makefile > @@ -132,8 +132,8 @@ EFI_OBJS-$(XEN_BUILD_EFI) := efi/relocs-dummy.o > > ifeq ($(CONFIG_LTO),y) > # Gather all LTO objects together > -prelink_lto.o: $(ALL_OBJS) > - $(LD_LTO) -r -o $@ $^ > +prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS) > + $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group > > # Link it with all the binary objects > prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $(EFI_OBJS-y) FORCE > @@ -142,10 +142,10 @@ prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $ > prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o FORCE > $(call if_changed,ld) > else > -prelink.o: $(ALL_OBJS) $(EFI_OBJS-y) FORCE > +prelink.o: $(ALL_OBJS) $(ALL_LIBS) $(EFI_OBJS-y) FORCE > $(call if_changed,ld) > > -prelink-efi.o: $(ALL_OBJS) FORCE > +prelink-efi.o: $(ALL_OBJS) $(ALL_LIBS) FORCE > $(call if_changed,ld) > endif > > diff --git a/xen/lib/Makefile b/xen/lib/Makefile > index 53b1da025e0d..b8814361d63e 100644 > --- a/xen/lib/Makefile > +++ b/xen/lib/Makefile > @@ -1,2 +1,3 @@ > -obj-y += ctype.o > obj-$(CONFIG_X86) += x86/ > + > +lib-y += ctype.o > >
On 09.12.2020 12:37, Bertrand Marquis wrote: >> On 23 Nov 2020, at 15:21, Jan Beulich <jbeulich@suse.com> wrote: >> >> In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT >> just to avoid bloating binaries when only some arch-es and/or >> configurations need generic library routines, combine objects under lib/ >> into an archive, which the linker then can pick the necessary objects >> out of. >> >> Note that we can't use thin archives just yet, until we've raised the >> minimum required binutils version suitably. >> >> Signed-off-by: Jan Beulich <jbeulich@suse.com> > Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> Thanks. >> @@ -60,7 +64,14 @@ include Makefile >> # --------------------------------------------------------------------------- >> >> quiet_cmd_ld = LD $@ >> -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) >> +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ >> + --start-group $(filter %.a,$(real-prereqs)) --end-group > > This might be a good idea to add a comment to explain why the start/end-group > is needed so that someone does not change this back in the future. Since we're trying to inherit Linux'es build system, I did look there and iirc there was no comment, so I didn't see a basis for us to have one. > Something like: put libraries between start/end group to have unused symbols removed. Now that's not the reason - why you describe is the default behavior for archives, and there is something like a "whole archive" option iirc to change to a mode where all objects get pulled out. Instead this is a symbol resolution thing aiui - by default earlier archives can't resolve undefined symbols first referenced by objects pulled out of later archives. Jan
Hi Jan, > On 9 Dec 2020, at 14:42, Jan Beulich <jbeulich@suse.com> wrote: > > On 09.12.2020 12:37, Bertrand Marquis wrote: >>> On 23 Nov 2020, at 15:21, Jan Beulich <jbeulich@suse.com> wrote: >>> >>> In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT >>> just to avoid bloating binaries when only some arch-es and/or >>> configurations need generic library routines, combine objects under lib/ >>> into an archive, which the linker then can pick the necessary objects >>> out of. >>> >>> Note that we can't use thin archives just yet, until we've raised the >>> minimum required binutils version suitably. >>> >>> Signed-off-by: Jan Beulich <jbeulich@suse.com> >> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> > > Thanks. > >>> @@ -60,7 +64,14 @@ include Makefile >>> # --------------------------------------------------------------------------- >>> >>> quiet_cmd_ld = LD $@ >>> -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) >>> +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ >>> + --start-group $(filter %.a,$(real-prereqs)) --end-group >> >> This might be a good idea to add a comment to explain why the start/end-group >> is needed so that someone does not change this back in the future. > > Since we're trying to inherit Linux'es build system, I did look > there and iirc there was no comment, so I didn't see a basis for > us to have one. > >> Something like: put libraries between start/end group to have unused symbols removed. > > Now that's not the reason - why you describe is the default > behavior for archives, and there is something like a "whole > archive" option iirc to change to a mode where all objects > get pulled out. Instead this is a symbol resolution thing > aiui - by default earlier archives can't resolve undefined > symbols first referenced by objects pulled out of later > archives. ah yes i remember seeing that. Maybe just add your last sentence in the commit message. Cheers Bertrand > > Jan
On Mon, Nov 23, 2020 at 04:21:19PM +0100, Jan Beulich wrote: > In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT > just to avoid bloating binaries when only some arch-es and/or > configurations need generic library routines, combine objects under lib/ > into an archive, which the linker then can pick the necessary objects > out of. > > Note that we can't use thin archives just yet, until we've raised the > minimum required binutils version suitably. > > Signed-off-by: Jan Beulich <jbeulich@suse.com> > --- > xen/Rules.mk | 29 +++++++++++++++++++++++++---- > xen/arch/arm/Makefile | 6 +++--- > xen/arch/x86/Makefile | 8 ++++---- > xen/lib/Makefile | 3 ++- > 4 files changed, 34 insertions(+), 12 deletions(-) > > diff --git a/xen/Rules.mk b/xen/Rules.mk > index d5e5eb33de39..aba6ca2a90f5 100644 > --- a/xen/Rules.mk > +++ b/xen/Rules.mk > @@ -60,7 +64,14 @@ include Makefile > # --------------------------------------------------------------------------- > > quiet_cmd_ld = LD $@ > -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) > +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ > + --start-group $(filter %.a,$(real-prereqs)) --end-group It might be a bit weird to modify the generic LD command for the benefit of only prelink.o objects but it's probably fine as long as we only use archives for lib.a. libelf and libfdt will just have --start/end-group added to there ld command line. So I guess the change is fine. The rest looks good, Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Thanks,
On 10.12.2020 15:47, Anthony PERARD wrote: > On Mon, Nov 23, 2020 at 04:21:19PM +0100, Jan Beulich wrote: >> --- a/xen/Rules.mk >> +++ b/xen/Rules.mk >> @@ -60,7 +64,14 @@ include Makefile >> # --------------------------------------------------------------------------- >> >> quiet_cmd_ld = LD $@ >> -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) >> +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ >> + --start-group $(filter %.a,$(real-prereqs)) --end-group > > It might be a bit weird to modify the generic LD command for the benefit > of only prelink.o objects but it's probably fine as long as we only use > archives for lib.a. libelf and libfdt will just have --start/end-group > added to there ld command line. So I guess the change is fine. I'm afraid I don't understand what the concern is. Neither libelf nor libfdt use any %.a right now. Or are you referring to them merely because it's just them which have got converted to using $(call if-changed ...), and your remark would eventually apply to e.g. built_in.o as well? And then further is all you're worried about the fact that there may be "--start-group --end-group" on the command line, i.e. with nothing inbetween? If so, besides possibly looking a little odd if someone inspected the command lines closely, what possible issue do you see? (If there is one, making the addition of both options conditional upon there being any/multiple %.a in the first place wouldn't be a big problem, albeit Linux also doesn't care whether ${KBUILD_VMLINUX_LIBS} is empty.) > The rest looks good, > Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Thanks, but I'd prefer the above clarified. Jan
On Fri, Dec 11, 2020 at 11:00:19AM +0100, Jan Beulich wrote: > On 10.12.2020 15:47, Anthony PERARD wrote: > > On Mon, Nov 23, 2020 at 04:21:19PM +0100, Jan Beulich wrote: > >> --- a/xen/Rules.mk > >> +++ b/xen/Rules.mk > >> @@ -60,7 +64,14 @@ include Makefile > >> # --------------------------------------------------------------------------- > >> > >> quiet_cmd_ld = LD $@ > >> -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) > >> +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ > >> + --start-group $(filter %.a,$(real-prereqs)) --end-group > > > > It might be a bit weird to modify the generic LD command for the benefit > > of only prelink.o objects but it's probably fine as long as we only use > > archives for lib.a. libelf and libfdt will just have --start/end-group > > added to there ld command line. So I guess the change is fine. > > I'm afraid I don't understand what the concern is. Neither libelf > nor libfdt use any %.a right now. Or are you referring to them > merely because it's just them which have got converted to using > $(call if-changed ...), and your remark would eventually apply to > e.g. built_in.o as well? And then further is all you're worried > about the fact that there may be "--start-group --end-group" on > the command line, i.e. with nothing inbetween? If so, besides > possibly looking a little odd if someone inspected the command > lines closely, what possible issue do you see? (If there is one, > making the addition of both options conditional upon there being > any/multiple %.a in the first place wouldn't be a big problem, > albeit Linux also doesn't care whether ${KBUILD_VMLINUX_LIBS} is > empty.) Well, maybe one day we might want to collect objects in build_in.a archives rather than build_in.o, like Linux does, but Xen is probably too small for that to have any impact on the time it takes to build. And if that happen, we will have to change the linker's command anyway to use --whole-archive. So the change is fine. As for "--start-group --end-group", yes it would just look odd, but I don't think there would by any issue with option added to the command line. > > The rest looks good, > > Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> > > Thanks, but I'd prefer the above clarified. > > Jan
On 23.11.2020 16:21, Jan Beulich wrote: > In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT > just to avoid bloating binaries when only some arch-es and/or > configurations need generic library routines, combine objects under lib/ > into an archive, which the linker then can pick the necessary objects > out of. > > Note that we can't use thin archives just yet, until we've raised the > minimum required binutils version suitably. > > Signed-off-by: Jan Beulich <jbeulich@suse.com> > --- > xen/Rules.mk | 29 +++++++++++++++++++++++++---- > xen/arch/arm/Makefile | 6 +++--- For this and patch 3 of the series, may I ask for an Arm side ack (or otherwise)? Thanks, Jan > xen/arch/x86/Makefile | 8 ++++---- > xen/lib/Makefile | 3 ++- > 4 files changed, 34 insertions(+), 12 deletions(-) > > diff --git a/xen/Rules.mk b/xen/Rules.mk > index d5e5eb33de39..aba6ca2a90f5 100644 > --- a/xen/Rules.mk > +++ b/xen/Rules.mk > @@ -41,12 +41,16 @@ ALL_OBJS-y += $(BASEDIR)/xsm/built_in.o > ALL_OBJS-y += $(BASEDIR)/arch/$(TARGET_ARCH)/built_in.o > ALL_OBJS-$(CONFIG_CRYPTO) += $(BASEDIR)/crypto/built_in.o > > +ALL_LIBS-y := $(BASEDIR)/lib/lib.a > + > # Initialise some variables > +lib-y := > targets := > CFLAGS-y := > AFLAGS-y := > > ALL_OBJS := $(ALL_OBJS-y) > +ALL_LIBS := $(ALL_LIBS-y) > > SPECIAL_DATA_SECTIONS := rodata $(foreach a,1 2 4 8 16, \ > $(foreach w,1 2 4, \ > @@ -60,7 +64,14 @@ include Makefile > # --------------------------------------------------------------------------- > > quiet_cmd_ld = LD $@ > -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) > +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ > + --start-group $(filter %.a,$(real-prereqs)) --end-group > + > +# Archive > +# --------------------------------------------------------------------------- > + > +quiet_cmd_ar = AR $@ > +cmd_ar = rm -f $@; $(AR) cPrs $@ $(real-prereqs) > > # Objcopy > # --------------------------------------------------------------------------- > @@ -86,6 +97,10 @@ obj-y := $(patsubst %/, %/built_in.o, $(obj-y)) > # tell kbuild to descend > subdir-obj-y := $(filter %/built_in.o, $(obj-y)) > > +# Libraries are always collected in one lib file. > +# Filter out objects already built-in > +lib-y := $(filter-out $(obj-y), $(sort $(lib-y))) > + > $(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): CFLAGS-y += -DINIT_SECTIONS_ONLY > > ifeq ($(CONFIG_COVERAGE),y) > @@ -129,7 +144,7 @@ include $(BASEDIR)/arch/$(TARGET_ARCH)/Rules.mk > c_flags += $(CFLAGS-y) > a_flags += $(CFLAGS-y) $(AFLAGS-y) > > -built_in.o: $(obj-y) $(extra-y) > +built_in.o: $(obj-y) $(if $(strip $(lib-y)),lib.a) $(extra-y) > ifeq ($(strip $(obj-y)),) > $(CC) $(c_flags) -c -x c /dev/null -o $@ > else > @@ -140,8 +155,14 @@ else > endif > endif > > +lib.a: $(lib-y) FORCE > + $(call if_changed,ar) > + > targets += built_in.o > -targets += $(filter-out $(subdir-obj-y), $(obj-y)) $(extra-y) > +ifneq ($(strip $(lib-y)),) > +targets += lib.a > +endif > +targets += $(filter-out $(subdir-obj-y), $(obj-y) $(lib-y)) $(extra-y) > targets += $(MAKECMDGOALS) > > built_in_bin.o: $(obj-bin-y) $(extra-y) > @@ -155,7 +176,7 @@ endif > PHONY += FORCE > FORCE: > > -%/built_in.o: FORCE > +%/built_in.o %/lib.a: FORCE > $(MAKE) -f $(BASEDIR)/Rules.mk -C $* built_in.o > > %/built_in_bin.o: FORCE > diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile > index 296c5e68bbc3..612a83b315c8 100644 > --- a/xen/arch/arm/Makefile > +++ b/xen/arch/arm/Makefile > @@ -90,14 +90,14 @@ endif > > ifeq ($(CONFIG_LTO),y) > # Gather all LTO objects together > -prelink_lto.o: $(ALL_OBJS) > - $(LD_LTO) -r -o $@ $^ > +prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS) > + $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group > > # Link it with all the binary objects > prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o > $(call if_changed,ld) > else > -prelink.o: $(ALL_OBJS) FORCE > +prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE > $(call if_changed,ld) > endif > > diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile > index 9b368632fb43..8f2180485b2b 100644 > --- a/xen/arch/x86/Makefile > +++ b/xen/arch/x86/Makefile > @@ -132,8 +132,8 @@ EFI_OBJS-$(XEN_BUILD_EFI) := efi/relocs-dummy.o > > ifeq ($(CONFIG_LTO),y) > # Gather all LTO objects together > -prelink_lto.o: $(ALL_OBJS) > - $(LD_LTO) -r -o $@ $^ > +prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS) > + $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group > > # Link it with all the binary objects > prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $(EFI_OBJS-y) FORCE > @@ -142,10 +142,10 @@ prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $ > prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o FORCE > $(call if_changed,ld) > else > -prelink.o: $(ALL_OBJS) $(EFI_OBJS-y) FORCE > +prelink.o: $(ALL_OBJS) $(ALL_LIBS) $(EFI_OBJS-y) FORCE > $(call if_changed,ld) > > -prelink-efi.o: $(ALL_OBJS) FORCE > +prelink-efi.o: $(ALL_OBJS) $(ALL_LIBS) FORCE > $(call if_changed,ld) > endif > > diff --git a/xen/lib/Makefile b/xen/lib/Makefile > index 53b1da025e0d..b8814361d63e 100644 > --- a/xen/lib/Makefile > +++ b/xen/lib/Makefile > @@ -1,2 +1,3 @@ > -obj-y += ctype.o > obj-$(CONFIG_X86) += x86/ > + > +lib-y += ctype.o > >
Hi Jan, On 18/12/2020 08:02, Jan Beulich wrote: > On 23.11.2020 16:21, Jan Beulich wrote: >> In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT >> just to avoid bloating binaries when only some arch-es and/or >> configurations need generic library routines, combine objects under lib/ >> into an archive, which the linker then can pick the necessary objects >> out of. >> >> Note that we can't use thin archives just yet, until we've raised the >> minimum required binutils version suitably. >> >> Signed-off-by: Jan Beulich <jbeulich@suse.com> >> --- >> xen/Rules.mk | 29 +++++++++++++++++++++++++---- >> xen/arch/arm/Makefile | 6 +++--- > > For this and patch 3 of the series, may I ask for an Arm side ack > (or otherwise)? For the 2 patches: Acked-by: Julien Grall <jgrall@amazon.com> Cheers,
diff --git a/xen/Rules.mk b/xen/Rules.mk index d5e5eb33de39..aba6ca2a90f5 100644 --- a/xen/Rules.mk +++ b/xen/Rules.mk @@ -41,12 +41,16 @@ ALL_OBJS-y += $(BASEDIR)/xsm/built_in.o ALL_OBJS-y += $(BASEDIR)/arch/$(TARGET_ARCH)/built_in.o ALL_OBJS-$(CONFIG_CRYPTO) += $(BASEDIR)/crypto/built_in.o +ALL_LIBS-y := $(BASEDIR)/lib/lib.a + # Initialise some variables +lib-y := targets := CFLAGS-y := AFLAGS-y := ALL_OBJS := $(ALL_OBJS-y) +ALL_LIBS := $(ALL_LIBS-y) SPECIAL_DATA_SECTIONS := rodata $(foreach a,1 2 4 8 16, \ $(foreach w,1 2 4, \ @@ -60,7 +64,14 @@ include Makefile # --------------------------------------------------------------------------- quiet_cmd_ld = LD $@ -cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(real-prereqs) +cmd_ld = $(LD) $(XEN_LDFLAGS) -r -o $@ $(filter-out %.a,$(real-prereqs)) \ + --start-group $(filter %.a,$(real-prereqs)) --end-group + +# Archive +# --------------------------------------------------------------------------- + +quiet_cmd_ar = AR $@ +cmd_ar = rm -f $@; $(AR) cPrs $@ $(real-prereqs) # Objcopy # --------------------------------------------------------------------------- @@ -86,6 +97,10 @@ obj-y := $(patsubst %/, %/built_in.o, $(obj-y)) # tell kbuild to descend subdir-obj-y := $(filter %/built_in.o, $(obj-y)) +# Libraries are always collected in one lib file. +# Filter out objects already built-in +lib-y := $(filter-out $(obj-y), $(sort $(lib-y))) + $(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): CFLAGS-y += -DINIT_SECTIONS_ONLY ifeq ($(CONFIG_COVERAGE),y) @@ -129,7 +144,7 @@ include $(BASEDIR)/arch/$(TARGET_ARCH)/Rules.mk c_flags += $(CFLAGS-y) a_flags += $(CFLAGS-y) $(AFLAGS-y) -built_in.o: $(obj-y) $(extra-y) +built_in.o: $(obj-y) $(if $(strip $(lib-y)),lib.a) $(extra-y) ifeq ($(strip $(obj-y)),) $(CC) $(c_flags) -c -x c /dev/null -o $@ else @@ -140,8 +155,14 @@ else endif endif +lib.a: $(lib-y) FORCE + $(call if_changed,ar) + targets += built_in.o -targets += $(filter-out $(subdir-obj-y), $(obj-y)) $(extra-y) +ifneq ($(strip $(lib-y)),) +targets += lib.a +endif +targets += $(filter-out $(subdir-obj-y), $(obj-y) $(lib-y)) $(extra-y) targets += $(MAKECMDGOALS) built_in_bin.o: $(obj-bin-y) $(extra-y) @@ -155,7 +176,7 @@ endif PHONY += FORCE FORCE: -%/built_in.o: FORCE +%/built_in.o %/lib.a: FORCE $(MAKE) -f $(BASEDIR)/Rules.mk -C $* built_in.o %/built_in_bin.o: FORCE diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile index 296c5e68bbc3..612a83b315c8 100644 --- a/xen/arch/arm/Makefile +++ b/xen/arch/arm/Makefile @@ -90,14 +90,14 @@ endif ifeq ($(CONFIG_LTO),y) # Gather all LTO objects together -prelink_lto.o: $(ALL_OBJS) - $(LD_LTO) -r -o $@ $^ +prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS) + $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group # Link it with all the binary objects prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $(call if_changed,ld) else -prelink.o: $(ALL_OBJS) FORCE +prelink.o: $(ALL_OBJS) $(ALL_LIBS) FORCE $(call if_changed,ld) endif diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile index 9b368632fb43..8f2180485b2b 100644 --- a/xen/arch/x86/Makefile +++ b/xen/arch/x86/Makefile @@ -132,8 +132,8 @@ EFI_OBJS-$(XEN_BUILD_EFI) := efi/relocs-dummy.o ifeq ($(CONFIG_LTO),y) # Gather all LTO objects together -prelink_lto.o: $(ALL_OBJS) - $(LD_LTO) -r -o $@ $^ +prelink_lto.o: $(ALL_OBJS) $(ALL_LIBS) + $(LD_LTO) -r -o $@ $(filter-out %.a,$^) --start-group $(filter %.a,$^) --end-group # Link it with all the binary objects prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $(EFI_OBJS-y) FORCE @@ -142,10 +142,10 @@ prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o $ prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o FORCE $(call if_changed,ld) else -prelink.o: $(ALL_OBJS) $(EFI_OBJS-y) FORCE +prelink.o: $(ALL_OBJS) $(ALL_LIBS) $(EFI_OBJS-y) FORCE $(call if_changed,ld) -prelink-efi.o: $(ALL_OBJS) FORCE +prelink-efi.o: $(ALL_OBJS) $(ALL_LIBS) FORCE $(call if_changed,ld) endif diff --git a/xen/lib/Makefile b/xen/lib/Makefile index 53b1da025e0d..b8814361d63e 100644 --- a/xen/lib/Makefile +++ b/xen/lib/Makefile @@ -1,2 +1,3 @@ -obj-y += ctype.o obj-$(CONFIG_X86) += x86/ + +lib-y += ctype.o
In order to (subsequently) drop odd things like CONFIG_NEEDS_LIST_SORT just to avoid bloating binaries when only some arch-es and/or configurations need generic library routines, combine objects under lib/ into an archive, which the linker then can pick the necessary objects out of. Note that we can't use thin archives just yet, until we've raised the minimum required binutils version suitably. Signed-off-by: Jan Beulich <jbeulich@suse.com> --- xen/Rules.mk | 29 +++++++++++++++++++++++++---- xen/arch/arm/Makefile | 6 +++--- xen/arch/x86/Makefile | 8 ++++---- xen/lib/Makefile | 3 ++- 4 files changed, 34 insertions(+), 12 deletions(-)