From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40632) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XNKUj-00032A-3f for qemu-devel@nongnu.org; Fri, 29 Aug 2014 07:37:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XNKUa-0002xI-Fs for qemu-devel@nongnu.org; Fri, 29 Aug 2014 07:37:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43319) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XNKUa-0002wW-8Y for qemu-devel@nongnu.org; Fri, 29 Aug 2014 07:37:20 -0400 Message-ID: <540065E6.6040508@redhat.com> Date: Fri, 29 Aug 2014 13:37:10 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1409281215-30711-1-git-send-email-famz@redhat.com> In-Reply-To: <1409281215-30711-1-git-send-email-famz@redhat.com> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH] rules.mak: Fix DSO build by pulling in archive symbols List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: kwolf@redhat.com, Peter Maydell , Michael Tokarev , stefanha@redhat.com, Richard Henderson Il 29/08/2014 05:00, Fam Zheng ha scritto: > Signed-off-by: Fam Zheng Perhaps add Suggested-by: H.J. Lu ? > +find-symbols = $(if $1, $(sort $(shell nm -f posix $1 | awk '$$2=="$2"{print $$1}' | sort -u))) No need to use both $(sort) and sort -u. Also please use -P instead of "-f posix", it's more portable. > +defined-symbols = $(call find-symbols,$1,T) What about data symbols? Those use other types like B, D or R. Perhaps use "nm -g" and remove U? > +undefined-symbols = $(call find-symbols,$1,U) "nm -g" would work here too (filtering U only here, of course). The other comments are aesthetic only. > +# All the .mo objects in -m variables are also added into corresponding -y > +# variable in unnest-vars, but filtered out here, when LINK is called. > +# > +# The .mo objects are supposed to be linked as a DSO, for module build. So here > +# they are only used as a placeholders to generate those "archive undefined" > +# symbol options (-Wl,-u,$symbol_name), which are the archive functions > +# referenced by the code in the DSO. > +# > +# Also the presence in -y variables will also guarantee they are built before > +# linking executables that will load them. So we can look up symbol reference > +# in LINK. > +# > +# This is necessary because the exectuable itself may not use the function, in > +# which case the function would not be linked in. Then the DSO loading will > +# fail because of the missing symbol. > +process-archive-undefs = $(filter-out %.a %.mo,$1) \ > + $(addprefix $(WL_U),\ > + $(filter $(call defined-symbols,$(filter %.a, $1)), \ > + $(call undefined-symbols,$(filter %.mo,$1)))) \ > + $(filter %.a,$1) > + > extract-libs = $(strip $(foreach o,$1,$($o-libs))) > expand-objs = $(strip $(sort $(filter %.o,$1)) \ > $(foreach o,$(filter %.mo,$1),$($o-objs)) \ > @@ -38,7 +64,8 @@ LINKPROG = $(or $(CXX),$(CC)) > > ifeq ($(LIBTOOL),) > LINK = $(call quiet-command, $(LINKPROG) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ \ > - $1 $(version-obj-y) $(call extract-libs,$1) $(LIBS)," LINK $(TARGET_DIR)$@") > + $(call process-archive-undefs, $1)\ Space before \ > + $(version-obj-y) $(call extract-libs,$1) $(LIBS)," LINK $(TARGET_DIR)$@") > else > LIBTOOL += $(if $(V),,--quiet) > %.lo: %.c > @@ -49,8 +76,9 @@ LIBTOOL += $(if $(V),,--quiet) > $(call quiet-command,$(LIBTOOL) --mode=compile --tag=CC dtrace -o $@ -G -s $<, " lt GEN $(TARGET_DIR)$@") > > LINK = $(call quiet-command,\ > - $(if $(filter %.lo %.la,$1),$(LIBTOOL) --mode=link --tag=CC \ > - )$(LINKPROG) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $1 \ > + $(if $(filter %.lo %.la,$1),$(LIBTOOL) --mode=link --tag=CC) \ > + $(LINKPROG) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ \ IIRC the parenthesis was there to make "V=1" a little prettier. > + $(call process-archive-undefs, $1)\ Space before \ > $(if $(filter %.lo %.la,$1),$(version-lobj-y),$(version-obj-y)) \ > $(if $(filter %.lo %.la,$1),$(LIBTOOLFLAGS)) \ > $(call extract-libs,$(1:.lo=.o)) $(LIBS),$(if $(filter %.lo %.la,$1),"lt LINK ", " LINK ")"$(TARGET_DIR)$@") > @@ -76,11 +104,17 @@ endif > > %$(DSOSUF): CFLAGS += -fPIC -DBUILD_DSO > %$(DSOSUF): LDFLAGS += $(LDFLAGS_SHARED) > -%$(DSOSUF): > +%$(DSOSUF): %.mo > $(call LINK,$^) > @# Copy to build root so modules can be loaded when program started without install > $(if $(findstring /,$@),$(call quiet-command,cp $@ $(subst /,-,$@), " CP $(subst /,-,$@)")) > > + > +LD_REL := $(CC) -nostdlib -Wl,-r > + > +%.mo: > + $(call quiet-command,$(LD_REL) -o $@ $^," LD -r $(TARGET_DIR)$@") > + > .PHONY: modules > modules: > > @@ -306,6 +340,9 @@ define unnest-vars > # For module build, build shared libraries during "make modules" > # For non-module build, add -m to -y > $(if $(CONFIG_MODULES), > + $(foreach o,$($v), > + $(eval $o: $($o-objs))) > + $(eval $(patsubst %-m,%-y,$v) += $($v)) > $(eval modules: $($v:%.mo=%$(DSOSUF))), > $(eval $(patsubst %-m,%-y,$v) += $(call expand-objs, $($v))))) > >