Re: [Qemu-devel] [PATCH] w32: Fix build with older gcc (unresolved symbol)

[Igor Mitsyanko <i.mitsyanko@gmail.com>]

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On 11.05.2013 10:41, Stefan Weil wrote:
> Am 10.05.2013 22:14, schrieb Igor Mitsyanko:
>> On 29.03.2013 21:20, Stefan Weil wrote:
>>> The cross i586-mingw32msvc-gcc 4.4.4 from Debian Squeeze does not
>>> support
>>> __sync_val_compare_and_swap by default.
>>>
>>> Using -march=i686 fixes that and should also result in better code.
>>>
>>> Signed-off-by: Stefan Weil <sw@weilnetz.de>
>>> ---
>>>
>>> Maybe this modification is also needed for native gcc-4.4 and older
>>> on Linux i386. If yes, we can move the new script code out of the
>>> MinGW conditional code.
>>>
>>> Newer versions of gcc obviously use -march=i686 by default and
>>> don't need the patch, but it also won't do any harm for those
>>> versions.
>>>
>>> Stefan
>>>
>> mingw is built with --build=mingw32 and looks like it defaults to
>> -march=i386 (I have gcc version 4.7.2).
>> Default build on windows is broken without this patch, it should be
>> applied to 1.5 probably.
>>
>> Tested-by: Igor Mitsyanko <i.mitsyanko@gmail.com>
>>
> With latest QEMU, -march=i486 is used and there should be no problem.
> If there still is a problem, we have to look for the reason.
>
> Could you please post the output from configure?
>
> Regards,
> Stefan
>

Right, looks like my configuration has __sync_fetch_and_and but doesn't 
have __sync_val_compare_and_swap. That's why configure check passes but 
build fails:

   LINK  arm-softmmu/qemu-system-armw.exe
../migration.o: In function `migrate_finish_set_state':
g:\qemu_develop_ws\qemu_upstream/migration.c:293: undefined reference to 
`__sync_val_compare_and_swap_4'
g:\qemu_develop_ws\qemu_upstream/migration.c:293: undefined reference to 
`__sync_val_compare_and_swap_4'
g:\qemu_develop_ws\qemu_upstream/migration.c:293: undefined reference to 
`__sync_val_compare_and_swap_4'
collect2.exe: error: ld returned 1 exit status
make[1]: *** [qemu-system-armw.exe] Error 1
make: *** [subdir-arm-softmmu] Error 2

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$ ./configure --target-list=arm-softmmu
Install prefix    c:/Program Files/QEMU
BIOS directory    c:/Program Files/QEMU
binary directory  c:/Program Files/QEMU
library directory c:/Program Files/QEMU/lib
libexec directory c:/Program Files/QEMU/libexec
include directory c:/Program Files/QEMU/include
config directory  c:/Program Files/QEMU
local state directory   c:/Program Files/QEMU
Source path       /g/qemu_develop_ws/qemu_upstream
C compiler        cc
Host C compiler   cc
Objective-C compiler cc
CFLAGS            -O2 -D_FORTIFY_SOURCE=2 -g
QEMU_CFLAGS       -m32 -D__USE_MINGW_ANSI_STDIO=1 -DWIN32_LEAN_AND_MEAN -DWINVER=0x501 -D_GNU_SOURCE -D_FILE_OFFSET_BITS
=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-st
rict-aliasing  -Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit
-self -Wignored-qualifiers -Wold-style-declaration -Wold-style-definition -Wtype-limits -fstack-protector-all  -IC:/ming
w/include/libpng14   -IC:/mingw/include/pixman-1
LDFLAGS           -Wl,--nxcompat -Wl,--no-seh -Wl,--dynamicbase -Wl,--warn-common -m32 -g
make              make
install           install
python            python
smbd              /usr/sbin/smbd
host CPU          i386
host big endian   no
target list       arm-softmmu
tcg debug enabled no
gprof enabled     no
sparse enabled    no
strip binaries    yes
profiler          no
static build      no
-Werror enabled   no
pixman            system
SDL support       yes
GTK support       no
curses support    no
curl support      yes
mingw32 support   yes
Audio drivers     winwave
Block whitelist
Mixer emulation   no
VirtFS support    no
VNC support       yes
VNC TLS support   no
VNC SASL support  no
VNC JPEG support  yes
VNC PNG support   yes
VNC WS support    no
xen support       no
brlapi support    no
bluez  support    no
Documentation     yes
NPTL support      no
GUEST_BASE        yes
PIE               no
vde support       no
Linux AIO support no
ATTR/XATTR support no
Install blobs     yes
KVM support       no
TCG interpreter   no
fdt support       no
preadv support    no
fdatasync         no
madvise           no
posix_madvise     no
sigev_thread_id   no
uuid support      no
libcap-ng support no
vhost-net support no
vhost-scsi support no
Trace backend     nop
Trace output file trace-<pid>
spice support     no (/)
rbd support       no
xfsctl support    no
nss used          no
libusb            no
usb net redir     no
GLX support       no
libiscsi support  no
build guest agent yes
seccomp support   no
coroutine backend win32
GlusterFS support no
virtio-blk-data-plane no
gcov              gcov
gcov enabled      no
TPM support       no
libssh2 support   no
TPM passthrough   no