Re: [Qemu-devel] [PATCH] libcacard: add libcacard.la target

[Anthony Liguori <anthony@codemonkey.ws>]

On 05/16/2011 08:25 AM, Alon Levy wrote:
> No flag to configure is required. Instead, added a libcacard.la target that
> is not built by default, only when requested explicitly via:
>
> mkdir build
> cd build
> ../configure
> make libcacard.la
> make install-libcacard
>
> Uses libtool to do actual linking of object files and shared library, and
> installing. Tested only under linux, but supposed to work on other systems as
> well.
>
> If libtool isn't found you get a message complaining about that, only at build
> time (since it is not a default target I did not add a message at configure
> time).
>
> Note: please ignore the following warning message, it is harmless, and fixing
> it would require using libtool to build trace-dtrace.lo which, since it isn't
> built by gcc, I don't know how to do.
>
>   *** Warning: Linking the shared library libcacard.la against the non-libtool
>   *** objects  ../trace-dtrace.o is not portable!

I don't think slipping in libtool like this is such a good idea.

Why do you need this target?

Isn't la just a static archive compiled with -fPIC?  Doesn't the whole 
code base need to be compiled with -fPIC then (and isn't the warning 
above a legitimate concern?).

Regards,

Anthony Liguori

> ---
>   Makefile           |   17 +++++++++++++++++
>   configure          |   12 +++++++++++-
>   libcacard/Makefile |   38 ++++++++++++++++++++++++++++++++++----
>   3 files changed, 62 insertions(+), 5 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 2b0438c..0215307 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -119,6 +119,23 @@ version.o: $(SRC_PATH)/version.rc config-host.mak
>
>   version-obj-$(CONFIG_WIN32) += version.o
>   ######################################################################
> +# Support building shared library libcacard
> +
> +.PHONY: libcacard.la install-libcacard
> +ifeq ($(LIBTOOL),)
> +libcacard.la:
> +	@echo libtool is missing, please install and rerun configure
> +
> +install-libcacard:
> +	@echo libtool is missing, please install and rerun configure
> +else
> +libcacard.la: $(GENERATED_HEADERS) $(oslib-obj-y) qemu-malloc.o qemu-timer-common.o $(trace-obj-y)
> +	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libcacard V="$(V)" TARGET_DIR="$*/" libcacard.la,)
> +
> +install-libcacard: libcacard.la
> +	$(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C libcacard V="$(V)" TARGET_DIR="$*/" install-libcacard,)
> +endif
> +######################################################################
>
>   qemu-img.o: qemu-img-cmds.h
>   qemu-img.o qemu-tool.o qemu-nbd.o qemu-io.o cmd.o: $(GENERATED_HEADERS)
> diff --git a/configure b/configure
> index 0627f1d..e62841e 100755
> --- a/configure
> +++ b/configure
> @@ -1276,6 +1276,15 @@ if ! has $pkg_config; then
>   fi
>
>   ##########################################
> +# libtool probe
> +
> +if ! has libtool; then
> +    libtool=
> +else
> +    libtool=libtool
> +fi
> +
> +##########################################
>   # Sparse probe
>   if test "$sparse" != "no" ; then
>     if has cgcc; then
> @@ -3060,6 +3069,7 @@ echo "AR=$ar">>  $config_host_mak
>   echo "OBJCOPY=$objcopy">>  $config_host_mak
>   echo "LD=$ld">>  $config_host_mak
>   echo "WINDRES=$windres">>  $config_host_mak
> +echo "LIBTOOL=$libtool">>  $config_host_mak
>   echo "CFLAGS=$CFLAGS">>  $config_host_mak
>   echo "QEMU_CFLAGS=$QEMU_CFLAGS">>  $config_host_mak
>   echo "QEMU_INCLUDES=$QEMU_INCLUDES">>  $config_host_mak
> @@ -3595,7 +3605,7 @@ if [ "$source_path" != `pwd` ]; then
>       # out of tree build
>       mkdir -p libcacard
>       rm -f libcacard/Makefile
> -    ln -s "$source_path/libcacard/Makefile" libcacard/Makefile
> +    symlink "$source_path/libcacard/Makefile" libcacard/Makefile
>   fi
>
>   d=libuser
> diff --git a/libcacard/Makefile b/libcacard/Makefile
> index 1d34df0..3a5ad61 100644
> --- a/libcacard/Makefile
> +++ b/libcacard/Makefile
> @@ -4,15 +4,45 @@
>
>   $(call set-vpath, $(SRC_PATH):$(SRC_PATH)/libcacard)
>
> -QEMU_OBJS=$(addprefix ../, $(oslib-obj-y) $(trace-obj-y) qemu-malloc.o qemu-timer-common.o)
> +QEMU_TRACE_OBJS=$(addprefix ../,$(trace-obj-y))
> +
> +QEMU_BASE_OBJS=$(addprefix ../,$(oslib-obj-y) qemu-malloc.o qemu-timer-common.o)
> +
> +# objects linked against normal qemu binaries, not compiled with libtool
> +QEMU_OBJS = $(QEMU_BASE_OBJS) $(QEMU_TRACE_OBJS)
> +
> +# objects linked into a shared library, built with libtool with -fPIC if required
> +QEMU_BASE_OBJS_LIB=$(addsuffix .lo,$(basename $(QEMU_BASE_OBJS)))
> +
> +QEMU_OBJS_LIB = $(QEMU_BASE_OBJS_LIB) $(QEMU_TRACE_OBJS)
>
>   QEMU_CFLAGS+=-I../
>
> +libcacard.lib-y=$(addsuffix .lo,$(basename $(libcacard-y)))
> +
>   vscclient: $(libcacard-y) $(QEMU_OBJS) vscclient.o
> -	$(call quiet-command,$(CC) $(libcacard_libs) -lrt -o $@ $^,"  LINK  $(TARGET_DIR)$@")
> +	$(call quiet-command,$(CC) $(libcacard_libs) -lrt -o $@ $^,"  LINK  $@")
> +
> +clean:
> +	rm -f *.o */*.o *.d */*.d *.a */*.a *~ */*~ vscclient libcacard.so *.lo .libs/* *.la
> +	rm -Rf .libs
>
>   all: vscclient
>
> -clean:
> -	rm -f *.o */*.o *.d */*.d *.a */*.a *~ */*~ vscclient
> +ifeq ($(LIBTOOL),)
> +libcacard.la:
> +	@echo libtool is missing, please install and rerun configure
> +
> +install-libcacard:
> +	@echo libtool is missing, please install and rerun configure
> +else
> +$(libcacard.lib-y) $(QEMU_BASE_OBJS_LIB) : %.lo: %.c
> +	$(call quiet-command,libtool --mode=compile --quiet --tag=CC $(CC) $(QEMU_CFLAGS) $(QEMU_INCLUDES) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  lt CC $@")
> +
> +libcacard.la: $(libcacard.lib-y) $(QEMU_OBJS_LIB)
> +	$(call quiet-command,libtool --mode=link --quiet --tag=CC $(CC) $(libcacard_libs) -lrt -rpath $(libdir) -o $@ $^,"  lt LINK $@")
>
> +install-libcacard: libcacard.la
> +	$(INSTALL_DIR) "$(DESTDIR)$(libdir)"
> +	libtool --mode=install $(INSTALL_PROG) libcacard.la "$(DESTDIR)$(libdir)"
> +endif