On 15.03.21 16:58, Thomas Huth wrote:
On 15/03/2021 16.50, Philippe Mathieu-Daudé wrote:
On 3/15/21 4:42 PM, Thomas Huth wrote:
On 15/03/2021 16.14, Christian Borntraeger wrote:
For some time now I do see the following, when I compile x86-softmmu
on s390:
FAILED: libcommon.fa.p/hw_intc_i8259.c.o
cc -Ilibcommon.fa.p -I. -I.. -Iqapi -Itrace -Iui -Iui/shader
-I/usr/include/capstone -I/usr/include/glib-2.0
-I/usr/lib64/glib-2.0/include -I/usr/include/libmount
-I/usr/include/blkid -I/usr/include/gio-unix-2.0
-I/usr/include/libusb-1.0 -I/usr/include/vte-2.91
-I/usr/include/pango-1.0 -I/usr/include/harfbuzz
-I/usr/include/freetype2 -I/usr/include/libpng16
-I/usr/include/fribidi -I/usr/include/libxml2 -I/usr/include/cairo
-I/usr/include/pixman-1 -I/usr/include/gtk-3.0
-I/usr/include/gdk-pixbuf-2.0 -I/usr/include/atk-1.0
-I/usr/include/at-spi2-atk/2.0 -I/usr/include/dbus-1.0
-I/usr/lib64/dbus-1.0/include -I/usr/include/at-spi-2.0
-I/usr/include/virgl -I/usr/include/p11-kit-1 -I/usr/include/SDL2
-I/usr/include/cacard -I/usr/include/nss3 -I/usr/include/nspr4
-I/usr/include/slirp -fdiagnostics-color=auto -pipe -Wall
-Winvalid-pch -Werror -std=gnu99 -O2 -g -isystem
/home/cborntra/REPOS/qemu/linux-headers -isystem linux-headers -iquote
. -iquote /home/cborntra/REPOS/qemu -iquote
/home/cborntra/REPOS/qemu/include -iquote
/home/cborntra/REPOS/qemu/disas/libvixl -iquote
/home/cborntra/REPOS/qemu/tcg/s390 -iquote
/home/cborntra/REPOS/qemu/accel/tcg -pthread -U_FORTIFY_SOURCE
-D_FORTIFY_SOURCE=2 -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64
-D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef
-Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common
-fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
-Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined
-Wimplicit-fallthrough=2 -Wno-missing-include-dirs
-Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -fPIC
-DSTRUCT_IOVEC_DEFINED -D_REENTRANT -Wno-undef -D_DEFAULT_SOURCE
-D_XOPEN_SOURCE=600 -DNCURSES_WIDECHAR -MD -MQ
libcommon.fa.p/hw_intc_i8259.c.o -MF
libcommon.fa.p/hw_intc_i8259.c.o.d -o libcommon.fa.p/hw_intc_i8259.c.o
-c ../hw/intc/i8259.c
../hw/intc/i8259.c: In function ‘pic_read_irq’:
../hw/intc/i8259.c:203:13: error: ‘irq2’ may be used uninitialized in
this function [-Werror=maybe-uninitialized]
203 | irq = irq2 + 8;
| ~~~~^~~~~~~~~~
cc1: all warnings being treated as errors
Due to other compile warnings I find this hard to bisect. Has anyone
seen this as well?
I've never seen this warnings so far... which compiler version is this?
Looking at the code, it seems to be a false positive to me.
https://www.mail-archive.com/qemu-devel@nongnu.org/msg599522.html
Oh, well, I completely forgot about that one ... but that was with -O3 ...
interesting that it now occurs with -O2, too!
But even after staring at the code for a while, I cannot see how irq2 may not
be initialized here ... so this really rather sounds like a compiler bug to
me...
Its not a bug, its part of the nature for "may be" warnings. The compiler
cannot figure out.
anyway, we could simply silence it by pre-initializing the variable to -1 or
so?
I can certainly spin up a patch with -1.
