compilation error with clang in util/async.c configured with ` CC=clang CXX=clang++ ../configure --target-list=x86_64-softmmu --enable-kvm --enable-curl --enable-debug --enable-jemalloc --enable-fuzzing --enable-sdl` and after make I get the following error related to c11 atomics. I'm using clang because I'm experimenting with fuzzer [glitz@archlinux /code/qemu/build]$ ninja -j5 [479/2290] Compiling C object libqemuutil.a.p/util_async.c.o FAILED: libqemuutil.a.p/util_async.c.o clang -Ilibqemuutil.a.p -I. -I.. -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/p11-kit-1 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -Ilinux-headers -Xclang -fcolor-diagnostics -pipe -Wall -Winvalid-pch -Werror -std=gnu99 -g -m64 -mcx16 -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-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -fsanitize=fuzzer-no-link -iquote /code/qemu/tcg/i386 -isystem /code/qemu/linux-headers -iquote . -iquote /code/qemu -iquote /code/qemu/accel/tcg -iquote /code/qemu/include -iquote /code/qemu/disas/libvixl -pthread -fPIC -MD -MQ libqemuutil.a.p/util_async.c.o -MF libqemuutil.a.p/util_async.c.o.d -o libqemuutil.a.p/util_async.c.o -c ../util/async.c ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid) old_flags = atomic_fetch_or(&bh->flags, BH_PENDING | new_flags); ^ ~~~~~~~~~~ /usr/lib/clang/10.0.1/include/stdatomic.h:138:42: note: expanded from macro 'atomic_fetch_or' #define atomic_fetch_or(object, operand) __c11_atomic_fetch_or(object, operand, __ATOMIC_SEQ_CST) ^ ~~~~~~ ../util/async.c:105:14: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid) *flags = atomic_fetch_and(&bh->flags, ^ ~~~~~~~~~~ /usr/lib/clang/10.0.1/include/stdatomic.h:144:43: note: expanded from macro 'atomic_fetch_and' #define atomic_fetch_and(object, operand) __c11_atomic_fetch_and(object, operand, __ATOMIC_SEQ_CST) ^ ~~~~~~ 2 errors generated. [483/2290] Compiling C object libqemuutil.a.p/util_qemu-error.c.o ninja: build stopped: subcommand failed. On Sun, Sep 13, 2020 at 06:56:12PM -0000, Amey Narkhede wrote: > configured with ` CC=clang CXX=clang++ ../configure --target- > list=x86_64-softmmu --enable-kvm --enable-curl --enable-debug --enable- > jemalloc --enable-fuzzing --enable-sdl` and after make I get the > following error related to c11 atomics. I'm using clang because I'm > experimenting with fuzzer > > [glitz@archlinux /code/qemu/build]$ ninja -j5 > [479/2290] Compiling C object libqemuutil.a.p/util_async.c.o > FAILED: libqemuutil.a.p/util_async.c.o > clang -Ilibqemuutil.a.p -I. -I.. -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/p11-kit-1 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -Ilinux-headers -Xclang -fcolor-diagnostics -pipe -Wall -Winvalid-pch -Werror -std=gnu99 -g -m64 -mcx16 -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-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels -Wexpansion-to-defined -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int -Wno-typedef-redefinition -Wno-tautological-type-limit-compare -fstack-protector-strong -fsanitize=fuzzer-no-link -iquote /code/qemu/tcg/i386 -isystem /code/qemu/linux-headers -iquote . -iquote /code/qemu -iquote /code/qemu/accel/tcg -iquote /code/qemu/include -iquote /code/qemu/disas/libvixl -pthread -fPIC -MD -MQ libqemuutil.a.p/util_async.c.o -MF libqemuutil.a.p/util_async.c.o.d -o libqemuutil.a.p/util_async.c.o -c ../util/async.c > ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid) > old_flags = atomic_fetch_or(&bh->flags, BH_PENDING | new_flags); > ^ ~~~~~~~~~~ > /usr/lib/clang/10.0.1/include/stdatomic.h:138:42: note: expanded from macro 'atomic_fetch_or' > #define atomic_fetch_or(object, operand) __c11_atomic_fetch_or(object, operand, __ATOMIC_SEQ_CST) > ^ ~~~~~~ > ../util/async.c:105:14: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid) > *flags = atomic_fetch_and(&bh->flags, > ^ ~~~~~~~~~~ > /usr/lib/clang/10.0.1/include/stdatomic.h:144:43: note: expanded from macro 'atomic_fetch_and' > #define atomic_fetch_and(object, operand) __c11_atomic_fetch_and(object, operand, __ATOMIC_SEQ_CST) > ^ ~~~~~~ > 2 errors generated. > [483/2290] Compiling C object libqemuutil.a.p/util_qemu-error.c.o > ninja: build stopped: subcommand failed. This happens when a system header file includes . QEMU's "atomic.h" conflicts with in that QEMU atomic variables do not need to be declared _Atomic. Please rerun the full clang command-line above from your meson build directory with -E instead of -c. Then upload the libqemuutil.a.p/util_async.c.o so we can see why stdatomic.h was included. Ok. So I attached the util_async.o file below On Mon, Sep 14, 2020 at 10:52:16AM -0000, Amey Narkhede wrote: > Ok. So I attached the util_async.o file below It looks like you can work around this issue with ./configure --disable-linux-io-uring. I'll investigate what can be done to solve the interference between and QEMU's "atomic.h" next week. Mailing list discussion about how to fix this: https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg07392.html I think this has been fixed here: https://gitlab.com/qemu-project/qemu/-/commit/d73415a315471a ... so I'm closing this now. If you still have problems, please open a new ticket in our new issue tracker here: https://gitlab.com/qemu-project/qemu/-/issues