Re: [Qemu-devel] [PATCH V3 1/5] libqblock build system

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

于 2012-9-18 18:05, Paolo Bonzini 写道:
> Il 18/09/2012 11:01, Wenchao Xia ha scritto:
>>    Libqblock was placed in new directory ./libqblock, libtool will build
>> dynamic library there, source files of block layer remains in ./block.
>> So block related source code will generate 3 sets of binary, first is old
>> ones used in qemu, second and third are non PIC and PIC ones in ./libqblock.
>>    GCC compiler flag visibility=hidden was used with special macro, to export
>> only symbols that was marked as PUBLIC.
>>
>> Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
>> ---
>>   Makefile                    |   13 ++++++++-
>>   Makefile.objs               |    6 ++++
>>   libqblock/Makefile          |   64 +++++++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 82 insertions(+), 1 deletions(-)
>>   create mode 100644 libqblock/Makefile
>>   create mode 100644 libqblock/libqblock-error.c
>>   create mode 100644 libqblock/libqblock.c
>>
>> diff --git a/Makefile b/Makefile
>> index 971e92f..b0b9b8d 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -164,6 +164,17 @@ qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y)
>>
>>   qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o
>>
>> +######################################################################
>> +# Support building shared library libqblock
>> +ifeq ($(LIBTOOL),)
>> +$(libqblock-lib-la):
>> +	@echo "libtool is missing, please install and rerun configure"; exit 1
>> +else
>> +$(libqblock-lib-la):
>> +	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libqblock V="$(V)" TARGET_DIR="$*/" $(libqblock-lib-la),)
>> +endif
>> +###########################################################################
>> +
>>   vscclient$(EXESUF): $(libcacard-y) $(oslib-obj-y) $(trace-obj-y) $(tools-obj-y) qemu-timer-common.o libcacard/vscclient.o
>>   	$(call quiet-command,$(CC) $(LDFLAGS) -o $@ $^ $(libcacard_libs) $(LIBS),"  LINK  $@")
>>
>> @@ -227,7 +238,7 @@ clean:
>>   	rm -rf qapi-generated
>>   	rm -rf qga/qapi-generated
>>   	$(MAKE) -C tests/tcg clean
>> -	for d in $(ALL_SUBDIRS) $(QEMULIBS) libcacard; do \
>> +	for d in $(ALL_SUBDIRS) $(QEMULIBS) libcacard libqblock; do \
>>   	if test -d $$d; then $(MAKE) -C $$d $@ || exit 1; fi; \
>>   	rm -f $$d/qemu-options.def; \
>>           done
>> diff --git a/Makefile.objs b/Makefile.objs
>> index 4412757..8a4c9fc 100644
>> --- a/Makefile.objs
>> +++ b/Makefile.objs
>> @@ -248,3 +248,9 @@ nested-vars += \
>>   	common-obj-y \
>>   	extra-obj-y
>>   dummy := $(call unnest-vars)
>> +
>> +#############################################################################
>> +# libqblock
>> +
>> +libqblock-lib-la = libqblock.la
>> +libqblock-lib-path = libqblock
>> diff --git a/libqblock/Makefile b/libqblock/Makefile
>> new file mode 100644
>> index 0000000..bf7abcc
>> --- /dev/null
>> +++ b/libqblock/Makefile
>> @@ -0,0 +1,64 @@
>> +###########################################################################
>> +# libqblock Makefile
>> +# Todo:
>> +#    1 trace related files is generated in this directory, move
>> +#  them to the root directory.
>> +##########################################################################
>> +-include ../config-host.mak
>> +-include $(SRC_PATH)/Makefile.objs
>> +-include $(SRC_PATH)/rules.mak
>> +
>> +#############################################################################
>> +# Library settings
>> +#############################################################################
>> +$(call set-vpath, $(SRC_PATH))
>> +
>> +#expand the foldered vars,especially ./block
>> +dummy := $(call unnest-vars-1)
>> +
>> +#library objects
>> +tools-obj-y = $(oslib-obj-y) $(trace-obj-y) qemu-tool.o qemu-timer.o \
>> +	qemu-timer-common.o main-loop.o notify.o \
>> +	iohandler.o cutils.o iov.o async.o
>> +tools-obj-$(CONFIG_POSIX) += compatfd.o
>
> Do you really need all of these?
>
   I guess only some .o are needed, but not sure how to pick them out, 
is there some tools which can help detect which object files are needed
in final linkage?

> (BTW, I posted recently a patch to move tools-obj-y to Makefile.objs.
> It doesn't apply anymore, I'll repost---but the conflicts are trivial).
>
   greate, then I can use tools-obj-y directly.

>> +libqblock-y=libqblock.o libqblock-error.o
>> +libqblock-lib-y=$(patsubst %.o,%.lo,$(libqblock-y))
>> +
>> +QEMU_OBJS=$(tools-obj-y) $(block-obj-y)
>> +QEMU_OBJS_FILTERED=$(filter %.o,$(QEMU_OBJS))
>
> What does this filter out?
>
   $(block-obj-y) contains /block, which would cause trouble in building,
so filtered it out.

> Paolo
>
>> +QEMU_OBJS_LIB=$(patsubst %.o, %.lo,$(QEMU_OBJS_FILTERED))
>> +
>> +QEMU_CFLAGS+= -I../ -I../include
>> +#adding magic macro define for symbol hiding and exposing
>> +QEMU_CFLAGS+= -fvisibility=hidden -D LIBQB_BUILD
>> +
>> +#dependency libraries
>> +LIBS+=-lz $(LIBS_TOOLS)
>> +
>> +#################################################################
>> +# Runtime rules
>> +#################################################################
>> +clean:
>> +	rm -f *.lo *.o *.d *.la libqblock-test trace.c trace.c-timestamp
>> +	rm -rf .libs block trace
>> +
>> +all: libqblock-test
>> +	@true
>> +
>> +help:
>> +	@echo type make libqblock-test at root dirtory, libtool is required
>> +
>> +#make dir block at runtime which would hold the output of block/*.c
>> +block:
>> +	@mkdir block
>> +
>> +ifeq ($(LIBTOOL),)
>> +$(libqblock-lib-la):
>> +	@echo "libtool is missing, please install and rerun configure"; exit 1
>> +else
>> +$(libqblock-lib-la): $(libqblock-lib-y) $(QEMU_OBJS_LIB)
>> +	$(call quiet-command,$(LIBTOOL) --mode=link --quiet --tag=CC $(CC) -rpath $(libdir) -o $@ $^ $(LIBS),"  lt LINK $@")
>> +endif
>> +
>> +.PHONY: libqblock.la
>> diff --git a/libqblock/libqblock-error.c b/libqblock/libqblock-error.c
>> new file mode 100644
>> index 0000000..e69de29
>> diff --git a/libqblock/libqblock.c b/libqblock/libqblock.c
>> new file mode 100644
>> index 0000000..e69de29
>>
>


-- 
Best Regards

Wenchao Xia