qemu/include
Peter Maydell 29191ea6a5 host-utils: Avoid using __builtin_subcll on buggy versions of Apple Clang
We use __builtin_subcll() to do a 64-bit subtract with borrow-in and
borrow-out when the host compiler supports it.  Unfortunately some
versions of Apple Clang have a bug in their implementation of this
intrinsic which means it returns the wrong value.  The effect is that
a QEMU built with the affected compiler will hang when emulating x86
or m68k float80 division.

The upstream LLVM issue is:
https://github.com/llvm/llvm-project/issues/55253

The commit that introduced the bug apparently never made it into an
upstream LLVM release without the subsequent fix
fffb6e6afd
but unfortunately it did make it into Apple Clang 14.0, as shipped
in Xcode 14.3 (14.2 is reported to be OK). The Apple bug number is
FB12210478.

Add ifdefs to avoid use of __builtin_subcll() on Apple Clang version
14 or greater.  There is not currently a version of Apple Clang which
has the bug fix -- when one appears we should be able to add an upper
bound to the ifdef condition so we can start using the builtin again.
We make the lower bound a conservative "any Apple clang with major
version 14 or greater" because the consequences of incorrectly
disabling the builtin when it would work are pretty small and the
consequences of not disabling it when we should are pretty bad.

Many thanks to those users who both reported this bug and also
did a lot of work in identifying the root cause; in particular
to Daniel Bertalan and osy.

Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1631
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1659
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Daniel Bertalan <dani@danielbertalan.dev>
Tested-by: Tested-By: Solra Bizna <solra@bizna.name>
Message-id: 20230622130823.1631719-1-peter.maydell@linaro.org
(cherry picked from commit b0438861ef)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-06-26 01:31:07 +03:00
..
authz
block block: Make bdrv_child_get_parent_aio_context I/O 2022-11-10 14:58:34 +01:00
chardev chardev: src buffer const for write functions 2022-09-29 14:38:05 +04:00
crypto crypto: Support export akcipher to pkcs8 2022-11-02 06:56:32 -04:00
disas target/loongarch: Add disassembler 2022-06-06 18:09:03 +00:00
exec migration: Use non-atomic ops for clear log bitmap 2022-11-21 11:58:10 +01:00
fpu fpu: Add rebias bool, value and operation 2022-08-31 14:08:05 -03:00
hw hw/arm/boot: Make write_bootloader() public as arm_write_bootloader() 2023-05-18 21:09:59 +03:00
io io/command: implement support for win32 2022-10-12 19:22:01 +04:00
libdecnumber
migration
monitor monitor: add missing coroutine_fn annotation 2022-10-27 20:14:11 +02:00
net Add G_GNUC_PRINTF to function qemu_set_info_str and fix related issues 2022-11-27 13:36:17 -05:00
qapi qerror: QERR_PERMISSION_DENIED is no longer used, drop 2022-10-27 07:57:18 +02:00
qemu host-utils: Avoid using __builtin_subcll on buggy versions of Apple Clang 2023-06-26 01:31:07 +03:00
qom qom/object: Remove circular include dependency 2022-06-28 10:53:32 +02:00
scsi scsi-disk: add SCSI_DISK_QUIRK_MODE_PAGE_VENDOR_SPECIFIC_APPLE quirk for Macintosh 2022-07-13 16:58:58 +02:00
semihosting semihosting: Allow optional use of semihosting from userspace 2022-09-13 17:18:21 +01:00
standard-headers m68k: rework BI_VIRT_RNG_SEED as BI_RNG_SEED 2022-10-21 20:46:10 +02:00
sysemu cryptodev: Add a lkcf-backend for cryptodev 2022-11-02 06:56:32 -04:00
tcg accel/tcg: Introduce tb_pc and log_pc 2022-10-04 12:13:12 -07:00
ui ui/console: Get tab completion working again in the SDL monitor vc 2022-09-23 13:42:09 +02:00
user misc: fix commonly doubled up words 2022-08-01 11:58:02 +02:00
elf.h include/elf.h: add s390x note types 2022-10-26 12:54:59 +04:00
glib-compat.h compiler.h: replace QEMU_NORETURN with G_NORETURN 2022-04-21 17:03:51 +04:00
qemu-io.h
qemu-main.h ui/cocoa: Run qemu_init in the main thread 2022-09-23 14:36:33 +02:00