peripherals: 0.902
permissions: 0.893
socket: 0.853
debug: 0.851
architecture: 0.847
hypervisor: 0.847
graphic: 0.840
mistranslation: 0.839
semantic: 0.832
virtual: 0.830
files: 0.827
user-level: 0.825
device: 0.824
performance: 0.818
network: 0.818
PID: 0.817
assembly: 0.816
vnc: 0.814
risc-v: 0.796
VMM: 0.795
register: 0.789
i386: 0.785
arm: 0.784
TCG: 0.782
x86: 0.779
ppc: 0.769
kernel: 0.761
KVM: 0.755
boot: 0.718

Qemu 2.3.0 failes to compile with GCC 5.1.0 and -flto

Compiling Qemu 2.3.0 failes with the following error:

x86_64-pc-linux-gnu-g++ -I/usr/include/pixman-1   -fPIE -DPIE -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common  -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-strong   -I/usr/include/libpng16  -I/usr/include/libusb-1.0  -I/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/work/qemu-2.3.0/tests -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -march=native -O2 -pipe -ggdb -floop-interchange -floop-strip-mine -floop-block -ftree-loop-distribution -fira-loop-pressure -ftree-vectorize -ftree-loop-linear -flto=5 -fuse-linker-plugin -Wl,-z,relro -Wl,-z,now -pie -m64 -Wl,-O1 -Wl,--as-needed -march=native -O2 -pipe -ggdb -floop-interchange -floop-strip-mine -floop-block -ftree-loop-distribution -fira-loop-pressure -ftree-vectorize -ftree-loop-linear -flto=5 -fuse-linker-plugin -Wl,-znow -Wl,--sort-common -Wl,--hash-style=gnu -Wl,--enable-new-dtags -o qemu-img qemu-img.o async.o thread-pool.o nbd.o block.o blockjob.o main-loop.o iohandler.o qemu-timer.o aio-posix.o qemu-io-cmds.o qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o qemu-coroutine-sleep.o coroutine-ucontext.o block/raw_bsd.o block/qcow.o block/vdi.o block/vmdk.o block/cloop.o block/dmg.o block/bochs.o block/vpc.o block/vvfat.o block/qcow2.o block/qcow2-refcount.o block/qcow2-cluster.o block/qcow2-snapshot.o block/qcow2-cache.o block/qed.o block/qed-gencb.o block/qed-l2-cache.o block/qed-table.o block/qed-cluster.o block/qed-check.o block/vhdx.o block/vhdx-endian.o block/vhdx-log.o block/parallels.o block/blkdebug.o block/blkverify.o block/block-backend.o block/snapshot.o block/qapi.o block/raw-posix.o block/linux-aio.o block/null.o block/mirror.o block/nbd.o block/nbd-client.o block/sheepdog.o block/accounting.o block/write-threshold.o block/curl.o  libqemuutil.a libqemustub.a   -lz -lbz2 -laio -lcurl -lm -lgthread-2.0 -pthread -lglib-2.0   -lz -lrt -lz -lcap-ng -luuid  -lutil
lto1: error: two or more sections for .gnu.lto_fprintf.2f4a95b725db6827
(null):0: confused by earlier errors, bailing out
make[1]: *** [/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/temp/ccEUT6Vq.ltrans11.ltrans.o] Error 1
make[1]: *** Waiting for unfinished jobs....
lto-wrapper: fatal error: make returned 2 exit status
compilation terminated.
/usr/lib/gcc/x86_64-pc-linux-gnu/5.1.0/../../../../x86_64-pc-linux-gnu/bin/ld: fatal error: lto-wrapper failed
collect2: error: ld returned 1 exit status
/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/work/qemu-2.3.0/rules.mak:122: recipe for target 'qemu-img' failed
make: *** [qemu-img] Error 1

I've found an old GCC bugreport with the same error: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52159 (which has been marked as dup of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59000) . I was able to reduce the object list to to three .o files which reproduce the error reliably: qemu-img.o qemu-io-cmds.o block/qapi.o.

Please let me know if you need further information.

This seems to be a GCC bug, not a QEMU bug? I'm going to close this bug, since it has been reported upstream with the GCC folks, and they don't seem to think this is an error on our side.