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authorPeter Maydell <peter.maydell@linaro.org>2013-10-22 10:58:41 +0100
committerAnthony Liguori <aliguori@amazon.com>2013-11-21 08:01:06 -0800
commit33effd3aab4a268fb573fd8d7e0fe0baed0cd61a (patch)
treed1db0ea25147325133006bd66e0553070aee288a
parent76c2975a6feb5c232698e982b7f798431457822f (diff)
downloadqemu-arm-33effd3aab4a268fb573fd8d7e0fe0baed0cd61a.tar.gz
atomic.h: Fix build with clang
clang defines __ATOMIC_SEQ_CST but its implementation of the __atomic_exchange() builtin differs from that of gcc. Move the __clang__ branch of the ifdef ladder to the top and fix its implementation (there is no such builtin as __sync_exchange), so we can compile with clang again. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1382435921-18438-1-git-send-email-peter.maydell@linaro.org Signed-off-by: Anthony Liguori <aliguori@amazon.com>
-rw-r--r--include/qemu/atomic.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index 0aa8913301..492bce1c1b 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -168,14 +168,14 @@
#endif
#ifndef atomic_xchg
-#ifdef __ATOMIC_SEQ_CST
+#if defined(__clang__)
+#define atomic_xchg(ptr, i) __sync_swap(ptr, i)
+#elif defined(__ATOMIC_SEQ_CST)
#define atomic_xchg(ptr, i) ({ \
typeof(*ptr) _new = (i), _old; \
__atomic_exchange(ptr, &_new, &_old, __ATOMIC_SEQ_CST); \
_old; \
})
-#elif defined __clang__
-#define atomic_xchg(ptr, i) __sync_exchange(ptr, i)
#else
/* __sync_lock_test_and_set() is documented to be an acquire barrier only. */
#define atomic_xchg(ptr, i) (smp_mb(), __sync_lock_test_and_set(ptr, i))