#ifndef __has_feature
#define __has_feature(x) 0
#endif
+#ifndef __has_extension
+ #define __has_extension(x) 0
+#endif
#if __GNUC__ && !__CHECKER__
#define NO_RETURN __attribute__((__noreturn__))
* while the specific MUTEX is held.
*
*
+ * On a variable A of mutex type:
+ *
+ * - OVS_ACQ_BEFORE(B), where B is a mutex or a comma-separated list of
+ * mutexes, declare that if both A and B are acquired at the same time,
+ * then A must be acquired before B. That is, B nests inside A.
+ *
+ * - OVS_ACQ_AFTER(B) is the opposite of OVS_ACQ_BEFORE(B), that is, it
+ * declares that A nests inside B.
+ *
+ *
* On a function, the following attributes apply to mutexes:
*
* - OVS_ACQUIRES(MUTEX) indicate that the function must be called without
* - OVS_LOCKS_EXCLUDED(MUTEX) indicates that the function may only be
* called when MUTEX is not held.
*
+ *
* The following variants, with the same syntax, apply to reader-writer locks:
*
* mutex rwlock, for reading rwlock, for writing
#define OVS_GUARDED __attribute__((guarded_var))
#define OVS_GUARDED_BY(...) __attribute__((guarded_by(__VA_ARGS__)))
#define OVS_RELEASES(...) __attribute__((unlock_function(__VA_ARGS__)))
-#define OVS_LOCKS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__)))
-#elif __CHECKER__
-/* "sparse" annotations for mutexes and mutex-like constructs.
- *
- * Change the thread-safety check annotations to use "context" attribute.
- *
- * OVS_MACRO_LOCK and OVS_MACRO_RELEASE are suitable for use within macros,
- * where there is no function prototype to annotate. */
-#define OVS_LOCKABLE
-#define OVS_REQ_RDLOCK(...) __attribute__((context(MUTEX, 1, 1)))
-#define OVS_ACQ_RDLOCK(...) __attribute__((context(MUTEX, 0, 1)))
-#define OVS_REQ_WRLOCK(...) __attribute__((context(MUTEX, 1, 1)))
-#define OVS_ACQ_WRLOCK(...) __attribute__((context(MUTEX, 0, 1)))
-#define OVS_REQUIRES(...) __attribute__((context(MUTEX, 1, 1)))
-#define OVS_ACQUIRES(...) __attribute__((context(MUTEX, 0, 1)))
-#define OVS_TRY_WRLOCK(RETVAL, ...)
-#define OVS_TRY_RDLOCK(RETVAL, ...)
-#define OVS_TRY_LOCK(REVAL, ...)
-#define OVS_GUARDED
-#define OVS_GUARDED_BY(...)
-#define OVS_RELEASES(...) __attribute__((context(MUTEX, 1, 0)))
-#define OVS_MACRO_LOCK(...) __context__(MUTEX, 0, 1)
-#define OVS_MACRO_RELEASE(...) __context__(MUTEX, 1, 0)
-#else
+#define OVS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__)))
+#define OVS_ACQ_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__)))
+#define OVS_ACQ_AFTER(...) __attribute__((acquired_after(__VA_ARGS__)))
+#define OVS_NO_THREAD_SAFETY_ANALYSIS \
+ __attribute__((no_thread_safety_analysis))
+#else /* not Clang */
#define OVS_LOCKABLE
#define OVS_REQ_RDLOCK(...)
#define OVS_ACQ_RDLOCK(...)
#define OVS_TRY_LOCK(...)
#define OVS_GUARDED
#define OVS_GUARDED_BY(...)
+#define OVS_EXCLUDED(...)
#define OVS_RELEASES(...)
-#define OVS_MACRO_LOCK(...)
-#define OVS_MACRO_RELEASE(...)
+#define OVS_ACQ_BEFORE(...)
+#define OVS_ACQ_AFTER(...)
+#define OVS_NO_THREAD_SAFETY_ANALYSIS
#endif
/* ISO C says that a C implementation may choose any integer type for an enum