qemu/util
Fangrui Song 25f74087c6 util/cutils: Fix incorrect integer->float conversion caught by clang
Clang does not like do_strtosz()'s code to guard against overflow:

    qemu/util/cutils.c:245:23: error: implicit conversion from 'unsigned long' to 'double' changes value from 18446744073709550592 to 18446744073709551616 [-Werror,-Wimplicit-int-float-conversion]

The warning will be enabled by default in clang 10. It is not
available for clang <= 9.

val * mul >= 0xfffffffffffffc00 is indeed wrong.  0xfffffffffffffc00
is not representable exactly as double.  It's half-way between the
representable values 0xfffffffffffff800 and 0x10000000000000000.
Which one we get is implementation-defined.  Bad.

We want val * mul > (the largest uint64_t exactly representable as
double).  That's 0xfffffffffffff800.  Write it as nextafter(0x1p64, 0)
with a suitable comment.

Signed-off-by: Fangrui Song <i@maskray.me>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Patch split, commit message improved]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20191122080039.12771-3-armbru@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Juan Quintela <quintela@redhat.com>
2019-11-25 06:00:05 +01:00
..
aio-posix.c
aio-wait.c
aio-win32.c
aiocb.c
async.c
atomic64.c
base64.c
bitmap.c
bitops.c
buffer.c
bufferiszero.c
cacheinfo.c
compatfd.c
coroutine-sigaltstack.c
coroutine-ucontext.c
coroutine-win32.c
crc32c.c
cutils.c util/cutils: Fix incorrect integer->float conversion caught by clang 2019-11-25 06:00:05 +01:00
drm.c
envlist.c
error.c
event_notifier-posix.c
event_notifier-win32.c
fifo8.c
filemonitor-inotify.c
filemonitor-stub.c
getauxval.c
guest-random.c
hbitmap.c
hexdump.c
host-utils.c
id.c
iov.c
iova-tree.c
keyval.c
lockcnt.c
log.c
main-loop.c
Makefile.objs
memfd.c
mmap-alloc.c
module.c
notify.c
osdep.c
oslib-posix.c
oslib-win32.c
pagesize.c
path.c
qdist.c
qemu-co-shared-resource.c
qemu-config.c
qemu-coroutine-io.c
qemu-coroutine-lock.c
qemu-coroutine-sleep.c
qemu-coroutine.c
qemu-error.c
qemu-openpty.c
qemu-option.c
qemu-print.c
qemu-progress.c
qemu-sockets.c
qemu-thread-common.h
qemu-thread-posix.c
qemu-thread-win32.c
qemu-timer-common.c
qemu-timer.c
qht.c
qsp.c
range.c
rcu.c
readline.c
stats64.c
sys_membarrier.c
systemd.c
thread-pool.c
throttle.c
timed-average.c
trace-events
unicode.c
uri.c
uuid.c
vfio-helpers.c