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Re: [Qemu-devel] [PATCH v2] build: replace weak symbols with a static li
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From: |
Blue Swirl |
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Subject: |
Re: [Qemu-devel] [PATCH v2] build: replace weak symbols with a static library |
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Date: |
Sun, 18 Nov 2012 21:09:56 +0000 |
Thanks, applied.
On Fri, Nov 16, 2012 at 5:35 PM, 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, in particular llvm-gcc is totally
> broken.
>
> This patch uses a surprisingly low-tech approach: a static library.
> 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).
>
> Thus, all stubs are placed in separate object files and put together in
> a static library. The library then is linked to all programs.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> Makefile | 16 +++++++++++-----
> Makefile.objs | 5 +++++
> Makefile.target | 4 ++--
> compiler.h | 11 -----------
> osdep.c | 32 --------------------------------
> oslib-win32.c | 7 -------
> qemu-sockets.c | 22 ----------------------
> qmp.c | 9 ---------
> rules.mak | 2 +-
> stubs/Makefile.objs | 8 ++++++++
> stubs/arch-query-cpu-def.c | 9 +++++++++
> stubs/fd-register.c | 6 ++++++
> stubs/fdset-add-fd.c | 7 +++++++
> stubs/fdset-find-fd.c | 7 +++++++
> stubs/fdset-get-fd.c | 7 +++++++
> stubs/fdset-remove-fd.c | 7 +++++++
> stubs/get-fd.c | 8 ++++++++
> stubs/set-fd-handler.c | 11 +++++++++++
> 18 file modificati, 89 inserzioni(+), 89 rimozioni(-)
> create mode 100644 stubs/Makefile.objs
> create mode 100644 stubs/arch-query-cpu-def.c
> create mode 100644 stubs/fd-register.c
> create mode 100644 stubs/fdset-add-fd.c
> create mode 100644 stubs/fdset-find-fd.c
> create mode 100644 stubs/fdset-get-fd.c
> create mode 100644 stubs/fdset-remove-fd.c
> create mode 100644 stubs/get-fd.c
> create mode 100644 stubs/set-fd-handler.c
>
> diff --git a/Makefile b/Makefile
> index 81c660f..b8301a2 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -157,6 +157,12 @@ version.o: $(SRC_PATH)/version.rc config-host.h
> $(call quiet-command,$(WINDRES) -I. -o $@ $<," RC
> $(TARGET_DIR)$@")
>
> version-obj-$(CONFIG_WIN32) += version.o
> +
> +######################################################################
> +# Build library with stubs
> +
> +libqemustub.a: $(stub-obj-y)
> +
> ######################################################################
> # Support building shared library libcacard
>
> @@ -183,13 +189,13 @@ tools-obj-y = $(oslib-obj-y) $(trace-obj-y) qemu-tool.o
> qemu-timer.o \
> main-loop.o iohandler.o error.o
> tools-obj-$(CONFIG_POSIX) += compatfd.o
>
> -qemu-img$(EXESUF): qemu-img.o $(tools-obj-y) $(block-obj-y)
> -qemu-nbd$(EXESUF): qemu-nbd.o $(tools-obj-y) $(block-obj-y)
> -qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y)
> +qemu-img$(EXESUF): qemu-img.o $(tools-obj-y) $(block-obj-y) libqemustub.a
> +qemu-nbd$(EXESUF): qemu-nbd.o $(tools-obj-y) $(block-obj-y) libqemustub.a
> +qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y) libqemustub.a
>
> qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o
>
> -vscclient$(EXESUF): $(libcacard-y) $(oslib-obj-y) $(trace-obj-y)
> libcacard/vscclient.o
> +vscclient$(EXESUF): $(libcacard-y) $(oslib-obj-y) $(trace-obj-y)
> libcacard/vscclient.o libqemustub.a
> $(call quiet-command,$(CC) $(LDFLAGS) -o $@ $^ $(libcacard_libs)
> $(LIBS)," LINK $@")
>
> fsdev/virtfs-proxy-helper$(EXESUF): fsdev/virtfs-proxy-helper.o
> fsdev/virtio-9p-marshal.o oslib-posix.o $(trace-obj-y)
> @@ -232,7 +238,7 @@ $(SRC_PATH)/qapi-schema.json
> $(SRC_PATH)/scripts/qapi-commands.py $(qapi-py)
> QGALIB_GEN=$(addprefix qga/qapi-generated/, qga-qapi-types.h
> qga-qapi-visit.h qga-qmp-commands.h)
> $(qga-obj-y) qemu-ga.o: $(QGALIB_GEN)
>
> -qemu-ga$(EXESUF): qemu-ga.o $(qga-obj-y) $(oslib-obj-y) $(trace-obj-y)
> $(qapi-obj-y) $(qobject-obj-y) $(version-obj-y)
> +qemu-ga$(EXESUF): qemu-ga.o $(qga-obj-y) $(oslib-obj-y) $(trace-obj-y)
> $(qapi-obj-y) $(qobject-obj-y) $(version-obj-y) libqemustub.a
>
> QEMULIBS=libuser libdis libdis-user
>
> diff --git a/Makefile.objs b/Makefile.objs
> index 37be7e2..5f112dc 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -1,4 +1,8 @@
> #######################################################################
> +# Stub library, linked in tools
> +stub-obj-y = stubs/
> +
> +#######################################################################
> # Target-independent parts used in system and user emulation
> universal-obj-y =
> universal-obj-y += qemu-log.o
> @@ -237,6 +241,7 @@ vl.o: QEMU_CFLAGS+=$(SDL_CFLAGS)
> QEMU_CFLAGS+=$(GLIB_CFLAGS)
>
> nested-vars += \
> + stub-obj-y \
> qga-obj-y \
> qom-obj-y \
> qapi-obj-y \
> diff --git a/Makefile.target b/Makefile.target
> index 3822bc5..8b658c0 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -162,12 +162,12 @@ endif #CONFIG_LINUX_USER
>
> ifdef QEMU_PROGW
> # The linker builds a windows executable. Make also a console executable.
> -$(QEMU_PROGW): $(all-obj-y)
> +$(QEMU_PROGW): $(all-obj-y) ../libqemustub.a
> $(call LINK,$^)
> $(QEMU_PROG): $(QEMU_PROGW)
> $(call quiet-command,$(OBJCOPY) --subsystem console $(QEMU_PROGW)
> $(QEMU_PROG)," GEN $(TARGET_DIR)$(QEMU_PROG)")
> else
> -$(QEMU_PROG): $(all-obj-y)
> +$(QEMU_PROG): $(all-obj-y) ../libqemustub.a
> $(call LINK,$^)
> endif
>
> diff --git a/compiler.h b/compiler.h
> index 55d7d74..2f7998b 100644
> --- a/compiler.h
> +++ b/compiler.h
> @@ -50,20 +50,9 @@
> # define __printf__ __gnu_printf__
> # endif
> # endif
> -# if defined(__APPLE__)
> -# define QEMU_WEAK_ALIAS(newname, oldname) \
> - static typeof(oldname) weak_##newname __attribute__((unused,
> weakref(#oldname)))
> -# define QEMU_WEAK_REF(newname, oldname) (weak_##newname ? weak_##newname :
> oldname)
> -# else
> -# define QEMU_WEAK_ALIAS(newname, oldname) \
> - typeof(oldname) newname __attribute__((weak, alias (#oldname)))
> -# define QEMU_WEAK_REF(newname, oldname) newname
> -# endif
> #else
> #define GCC_ATTR /**/
> #define GCC_FMT_ATTR(n, m)
> -#define QEMU_WEAK_ALIAS(newname, oldname) \
> - _Pragma("weak " #newname "=" #oldname)
> #endif
>
> #endif /* COMPILER_H */
> diff --git a/osdep.c b/osdep.c
> index 2f7a491..3a63d26 100644
> --- a/osdep.c
> +++ b/osdep.c
> @@ -54,38 +54,6 @@ static bool fips_enabled = false;
>
> static const char *qemu_version = QEMU_VERSION;
>
> -static int default_fdset_get_fd(int64_t fdset_id, int flags)
> -{
> - return -1;
> -}
> -QEMU_WEAK_ALIAS(monitor_fdset_get_fd, default_fdset_get_fd);
> -#define monitor_fdset_get_fd \
> - QEMU_WEAK_REF(monitor_fdset_get_fd, default_fdset_get_fd)
> -
> -static int default_fdset_dup_fd_add(int64_t fdset_id, int dup_fd)
> -{
> - return -1;
> -}
> -QEMU_WEAK_ALIAS(monitor_fdset_dup_fd_add, default_fdset_dup_fd_add);
> -#define monitor_fdset_dup_fd_add \
> - QEMU_WEAK_REF(monitor_fdset_dup_fd_add, default_fdset_dup_fd_add)
> -
> -static int default_fdset_dup_fd_remove(int dup_fd)
> -{
> - return -1;
> -}
> -QEMU_WEAK_ALIAS(monitor_fdset_dup_fd_remove, default_fdset_dup_fd_remove);
> -#define monitor_fdset_dup_fd_remove \
> - QEMU_WEAK_REF(monitor_fdset_dup_fd_remove, default_fdset_dup_fd_remove)
> -
> -static int default_fdset_dup_fd_find(int dup_fd)
> -{
> - return -1;
> -}
> -QEMU_WEAK_ALIAS(monitor_fdset_dup_fd_find, default_fdset_dup_fd_find);
> -#define monitor_fdset_dup_fd_find \
> - QEMU_WEAK_REF(monitor_fdset_dup_fd_remove, default_fdset_dup_fd_find)
> -
> int socket_set_cork(int fd, int v)
> {
> #if defined(SOL_TCP) && defined(TCP_CORK)
> diff --git a/oslib-win32.c b/oslib-win32.c
> index 326a2bd..51b33e8 100644
> --- a/oslib-win32.c
> +++ b/oslib-win32.c
> @@ -32,13 +32,6 @@
> #include "trace.h"
> #include "qemu_socket.h"
>
> -static void default_qemu_fd_register(int fd)
> -{
> -}
> -QEMU_WEAK_ALIAS(qemu_fd_register, default_qemu_fd_register);
> -#define qemu_fd_register \
> - QEMU_WEAK_REF(qemu_fd_register, default_qemu_fd_register)
> -
> void *qemu_oom_check(void *ptr)
> {
> if (ptr == NULL) {
> diff --git a/qemu-sockets.c b/qemu-sockets.c
> index abcd791..cfed9c5 100644
> --- a/qemu-sockets.c
> +++ b/qemu-sockets.c
> @@ -61,28 +61,6 @@ static QemuOptsList dummy_opts = {
> },
> };
>
> -static int default_monitor_get_fd(Monitor *mon, const char *name, Error
> **errp)
> -{
> - error_setg(errp, "only QEMU supports file descriptor passing");
> - return -1;
> -}
> -QEMU_WEAK_ALIAS(monitor_get_fd, default_monitor_get_fd);
> -#define monitor_get_fd \
> - QEMU_WEAK_REF(monitor_get_fd, default_monitor_get_fd)
> -
> -static int default_qemu_set_fd_handler2(int fd,
> - IOCanReadHandler *fd_read_poll,
> - IOHandler *fd_read,
> - IOHandler *fd_write,
> - void *opaque)
> -
> -{
> - abort();
> -}
> -QEMU_WEAK_ALIAS(qemu_set_fd_handler2, default_qemu_set_fd_handler2);
> -#define qemu_set_fd_handler2 \
> - QEMU_WEAK_REF(qemu_set_fd_handler2, default_qemu_set_fd_handler2)
> -
> static int inet_getport(struct addrinfo *e)
> {
> struct sockaddr_in *i4;
> diff --git a/qmp.c b/qmp.c
> index 13e83a5..e3a7f0b 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -471,15 +471,6 @@ DevicePropertyInfoList *qmp_device_list_properties(const
> char *typename,
> return prop_list;
> }
>
> -static CpuDefinitionInfoList *default_arch_query_cpu_definitions(Error
> **errp)
> -{
> - error_set(errp, QERR_NOT_SUPPORTED);
> - return NULL;
> -}
> -QEMU_WEAK_ALIAS(arch_query_cpu_definitions,
> default_arch_query_cpu_definitions);
> -#define arch_query_cpu_definitions \
> - QEMU_WEAK_REF(arch_query_cpu_definitions,
> default_arch_query_cpu_definitions)
> -
> CpuDefinitionInfoList *qmp_query_cpu_definitions(Error **errp)
> {
> return arch_query_cpu_definitions(errp);
> diff --git a/rules.mak b/rules.mak
> index 1b173aa..d0b04e4 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -31,7 +31,7 @@ endif
> %.o: %.m
> $(call quiet-command,$(OBJCC) $(QEMU_INCLUDES) $(QEMU_CFLAGS)
> $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<," OBJC $(TARGET_DIR)$@")
>
> -LINK = $(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@
> $(sort $(1)) $(LIBS)," LINK $(TARGET_DIR)$@")
> +LINK = $(call quiet-command,$(CC) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o $@
> $(sort $(filter %.o, $1)) $(filter-out %.o, $1) $(LIBS)," LINK
> $(TARGET_DIR)$@")
>
> %$(EXESUF): %.o
> $(call LINK,$^)
> diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
> new file mode 100644
> index 0000000..035b29a
> --- /dev/null
> +++ b/stubs/Makefile.objs
> @@ -0,0 +1,8 @@
> +stub-obj-y += arch-query-cpu-def.o
> +stub-obj-y += fdset-add-fd.o
> +stub-obj-y += fdset-find-fd.o
> +stub-obj-y += fdset-get-fd.o
> +stub-obj-y += fdset-remove-fd.o
> +stub-obj-y += get-fd.o
> +stub-obj-y += set-fd-handler.o
> +stub-obj-$(CONFIG_WIN32) += fd-register.o
> diff --git a/stubs/arch-query-cpu-def.c b/stubs/arch-query-cpu-def.c
> new file mode 100644
> index 0000000..47b5246
> --- /dev/null
> +++ b/stubs/arch-query-cpu-def.c
> @@ -0,0 +1,9 @@
> +#include "qemu-common.h"
> +#include "arch_init.h"
> +#include "qerror.h"
> +
> +CpuDefinitionInfoList *arch_query_cpu_definitions(Error **errp)
> +{
> + error_set(errp, QERR_NOT_SUPPORTED);
> + return NULL;
> +}
> diff --git a/stubs/fd-register.c b/stubs/fd-register.c
> new file mode 100644
> index 0000000..813b6dd
> --- /dev/null
> +++ b/stubs/fd-register.c
> @@ -0,0 +1,6 @@
> +#include "qemu-common.h"
> +#include "main-loop.h"
> +
> +void qemu_fd_register(int fd)
> +{
> +}
> diff --git a/stubs/fdset-add-fd.c b/stubs/fdset-add-fd.c
> new file mode 100644
> index 0000000..09fe2a8
> --- /dev/null
> +++ b/stubs/fdset-add-fd.c
> @@ -0,0 +1,7 @@
> +#include "qemu-common.h"
> +#include "monitor.h"
> +
> +int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd)
> +{
> + return -1;
> +}
> diff --git a/stubs/fdset-find-fd.c b/stubs/fdset-find-fd.c
> new file mode 100644
> index 0000000..f82baa0
> --- /dev/null
> +++ b/stubs/fdset-find-fd.c
> @@ -0,0 +1,7 @@
> +#include "qemu-common.h"
> +#include "monitor.h"
> +
> +int monitor_fdset_dup_fd_find(int dup_fd)
> +{
> + return -1;
> +}
> diff --git a/stubs/fdset-get-fd.c b/stubs/fdset-get-fd.c
> new file mode 100644
> index 0000000..4106cf9
> --- /dev/null
> +++ b/stubs/fdset-get-fd.c
> @@ -0,0 +1,7 @@
> +#include "qemu-common.h"
> +#include "monitor.h"
> +
> +int monitor_fdset_get_fd(int64_t fdset_id, int flags)
> +{
> + return -1;
> +}
> diff --git a/stubs/fdset-remove-fd.c b/stubs/fdset-remove-fd.c
> new file mode 100644
> index 0000000..861b312
> --- /dev/null
> +++ b/stubs/fdset-remove-fd.c
> @@ -0,0 +1,7 @@
> +#include "qemu-common.h"
> +#include "monitor.h"
> +
> +int monitor_fdset_dup_fd_remove(int dupfd)
> +{
> + return -1;
> +}
> diff --git a/stubs/get-fd.c b/stubs/get-fd.c
> new file mode 100644
> index 0000000..3561ab6
> --- /dev/null
> +++ b/stubs/get-fd.c
> @@ -0,0 +1,8 @@
> +#include "qemu-common.h"
> +#include "monitor.h"
> +
> +int monitor_get_fd(Monitor *mon, const char *name, Error **errp)
> +{
> + error_setg(errp, "only QEMU supports file descriptor passing");
> + return -1;
> +}
> diff --git a/stubs/set-fd-handler.c b/stubs/set-fd-handler.c
> new file mode 100644
> index 0000000..4807b5d
> --- /dev/null
> +++ b/stubs/set-fd-handler.c
> @@ -0,0 +1,11 @@
> +#include "qemu-common.h"
> +#include "main-loop.h"
> +
> +int qemu_set_fd_handler2(int fd,
> + IOCanReadHandler *fd_read_poll,
> + IOHandler *fd_read,
> + IOHandler *fd_write,
> + void *opaque)
> +{
> + abort();
> +}
> --
> 1.7.12.1
>