Hi, > On 23 Nov 2020, at 15:21, Jan Beulich <jbeul...@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 <jbeul...@suse.com> Reviewed-by: Bertrand Marquis <bertrand.marq...@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 > >
