[Qemu-devel] [PATCH] configure: add -Wno-format-truncation to QEMU_CFLAGS

[Eduardo Otubo]

Compilation breaks on GCC 7.1.1 20170622 (Fedora 26), thus adding
-Wno-format-truncation to QEMU_CFLAGS on configure script is neecssary.

    hw/usb/bus.c: In function ‘usb_port_location’:
    hw/usb/bus.c:410:66: error: ‘%d’ directive output may be truncated writing 
between 1 and 11 bytes into a region of size between 0 and 15 
[-Werror=format-truncation=]
             snprintf(downstream->path, sizeof(downstream->path), "%s.%d",
                                                                      ^~
    In file included from /usr/include/stdio.h:939:0,
                     from 
/home/otubo/develop/qemu/otubo/include/qemu/osdep.h:68,
                     from hw/usb/bus.c:1:
    /usr/include/bits/stdio2.h:64:10: note: ‘__builtin___snprintf_chk’ output 
between 3 and 28 bytes into a destination of size 16
       return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            __bos (__s), __fmt, __va_arg_pack ());
            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    cc1: all warnings being treated as errors
    make: *** [/home/otubo/develop/qemu/otubo/rules.mak:66: hw/usb/bus.o] Error 
1
    make: *** Waiting for unfinished jobs....

Signed-off-by: Eduardo Otubo <address@hidden>
---
This warning looks pretty much bogus to me. Since building with -Werror is
essential, we should add this flag to configure. If someone thinks this warning
is not a false positive, feel free to drop this patch.
 configure | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure b/configure
index befebe27e3..5d5507b3a0 100755
--- a/configure
+++ b/configure
@@ -482,6 +482,7 @@ ARFLAGS="${ARFLAGS-rv}"
 # left shift of signed integers is well defined and has the expected
 # 2s-complement style results. (Both clang and gcc agree that it
 # provides these semantics.)
+QEMU_CFLAGS="-Wno-format-truncation $QEMU_CFLALGS"
 QEMU_CFLAGS="-fno-strict-aliasing -fno-common -fwrapv $QEMU_CFLAGS"
 QEMU_CFLAGS="-Wall -Wundef -Wwrite-strings -Wmissing-prototypes $QEMU_CFLAGS"
 QEMU_CFLAGS="-Wstrict-prototypes -Wredundant-decls $QEMU_CFLAGS"
-- 
2.13.3