Re: [Qemu-devel] [RFC/RFT PATCH] build: replace weak symbols with a static library

[Peter Maydell]

On 16 November 2012 15:50, Paolo Bonzini <address@hidden> wrote:
> Weak symbols were a nice idea, but they turned out not to be
> a good one.  Toolchain support is just too sparse.
>
> This patch uses a surprisingly low-tech approach, i.e. static
> libraries.  Symbols in a static library are always overridden
> by symbols in an object file.  Furthermore, if you place each
> function in a separate source file, object files for unused
> functions will not be taken in.  This means that each function
> can use all the dependencies that it needs (especially QAPI
> stuff such as error_setg).
>
> All stubs are placed in separate object files and put together
> in a static library.  The library then is linked to all
> programs.

I think this is definitely a better approach; thanks for taking
the time to implement it. That said, this patch doesn't build on
MacOS:

manooth$ make V=1
make  BUILD_DIR=/Users/pm215/src/qemu -C libdis V="1" TARGET_DIR="libdis/" all
make  BUILD_DIR=/Users/pm215/src/qemu -C arm-softmmu V="1"
TARGET_DIR="arm-softmmu/" all
rm -f libqemustub.a && ar rcs libqemustub.a
ar: no archive members specified
usage:  ar -d [-TLsv] archive file ...
        ar -m [-TLsv] archive file ...
        ar -m [-abiTLsv] position archive file ...
        ar -p [-TLsv] archive [file ...]
        ar -q [-cTLsv] archive file ...
        ar -r [-cuTLsv] archive file ...
        ar -r [-abciuTLsv] position archive file ...
        ar -t [-TLsv] archive [file ...]
        ar -x [-ouTLsv] archive [file ...]
make[1]: *** [libqemustub.a] Error 1
make: *** [subdir-arm-softmmu] Error 2


And it doesn't build on Linux:

ccache gcc -Wl,--warn-common -Wl,-z,relro -Wl,-z,now -pie -m64 -g  -o
vscclient libcacard/cac.o libcacard/event.o libcacard/vcard.o
libcacard/vreader.o libcacard/vcard_emul_nss.o
libcacard/vcard_emul_type.o libcacard/card_7816.o osdep.o cutils.o
qemu-timer-common.o oslib-posix.o qemu-thread-posix.o trace.o
trace/default.o trace/control.o libcacard/vscclient.o -lnss3
-lnssutil3 -lsmime3 -lssl3 -lplds4 -lplc4 -lnspr4 -lpthread -ldl
-pthread -lgthread-2.0 -lrt -lglib-2.0   -lrt -pthread -lgthread-2.0
-lrt -lglib-2.0    -lz -lrbd -lrados -lcurl   -lvdeplug -luuid  -laio
osdep.o: In function `qemu_open':
/home/petmay01/linaro/qemu-from-laptop/qemu/osdep.c:166: undefined
reference to `monitor_fdset_get_fd'
/home/petmay01/linaro/qemu-from-laptop/qemu/osdep.c:176: undefined
reference to `monitor_fdset_dup_fd_add'
osdep.o: In function `qemu_close':
/home/petmay01/linaro/qemu-from-laptop/qemu/osdep.c:212: undefined
reference to `monitor_fdset_dup_fd_find'
/home/petmay01/linaro/qemu-from-laptop/qemu/osdep.c:218: undefined
reference to `monitor_fdset_dup_fd_remove'
collect2: ld returned 1 exit status
make: *** [vscclient] Error 1



-- PMM