#ifndef COMPILER_H
#define COMPILER_H 1
+#ifndef __has_feature
+ #define __has_feature(x) 0
+#endif
+
#if __GNUC__ && !__CHECKER__
#define NO_RETURN __attribute__((__noreturn__))
#define OVS_UNUSED __attribute__((__unused__))
#define OVS_UNLIKELY(CONDITION) (!!(CONDITION))
#endif
-#ifdef __CHECKER__
-/* "sparse" annotations for mutexes and mutex-like constructs.
+#if __has_feature(c_thread_safety_attributes)
+/* "clang" annotations for thread safety check.
+ *
+ * OVS_LOCKABLE indicates that the struct contains mutex element
+ * which can be locked by functions like ovs_mutex_lock().
+ *
+ * Below, the word MUTEX stands for the name of an object with an OVS_LOCKABLE
+ * struct type. It can also be a comma-separated list of multiple structs,
+ * e.g. to require a function to hold multiple locks while invoked.
+ *
+ *
+ * On a variable:
+ *
+ * - OVS_GUARDED indicates that the variable may only be accessed some mutex
+ * is held.
+ *
+ * - OVS_GUARDED_BY(MUTEX) indicates that the variable may only be accessed
+ * while the specific MUTEX is held.
*
- * In a function prototype, OVS_ACQUIRES(MUTEX) indicates that the function
- * must be called without MUTEX acquired and that it returns with MUTEX
- * acquired. OVS_RELEASES(MUTEX) indicates the reverse. OVS_MUST_HOLD
- * indicates that the function must be called with MUTEX acquired by the
- * caller and that the function does not release MUTEX.
*
- * In practice, sparse ignores the MUTEX argument. It need not even be a
- * valid expression. It is meant to indicate to human readers what mutex is
- * being acquired.
+ * On a function, the following attributes apply to mutexes:
+ *
+ * - OVS_ACQUIRES(MUTEX) indicate that the function must be called without
+ * holding MUTEX and that it returns holding MUTEX.
+ *
+ * - OVS_RELEASES(MUTEX) indicates that the function may only be called with
+ * MUTEX held and that it returns with MUTEX released. It can be used for
+ * all types of MUTEX.
+ *
+ * - OVS_TRY_LOCK(RETVAL, MUTEX) indicate that the function will try to
+ * acquire MUTEX. RETVAL is an integer or boolean value specifying the
+ * return value of a successful lock acquisition.
+ *
+ * - OVS_REQUIRES(MUTEX) indicate that the function may only be called with
+ * MUTEX held and that the function does not release MUTEX.
+ *
+ * - 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
+ * ------------------- ------------------- -------------------
+ * OVS_ACQUIRES OVS_ACQ_RDLOCK OVS_ACQ_WRLOCK
+ * OVS_RELEASES OVS_RELEASES OVS_RELEASES
+ * OVS_TRY_LOCK OVS_TRY_RDLOCK OVS_TRY_WRLOCK
+ * OVS_REQUIRES OVS_REQ_RDLOCK OVS_REQ_WRLOCK
+ * OVS_LOCKS_EXCLUDED OVS_LOCKS_EXCLUDED OVS_LOCKS_EXCLUDED
+ */
+#define OVS_LOCKABLE __attribute__((lockable))
+#define OVS_REQ_RDLOCK(...) __attribute__((shared_locks_required(__VA_ARGS__)))
+#define OVS_ACQ_RDLOCK(...) __attribute__((shared_lock_function(__VA_ARGS__)))
+#define OVS_REQ_WRLOCK(...) \
+ __attribute__((exclusive_locks_required(__VA_ARGS__)))
+#define OVS_ACQ_WRLOCK(...) \
+ __attribute__((exclusive_lock_function(__VA_ARGS__)))
+#define OVS_REQUIRES(...) \
+ __attribute__((exclusive_locks_required(__VA_ARGS__)))
+#define OVS_ACQUIRES(...) \
+ __attribute__((exclusive_lock_function(__VA_ARGS__)))
+#define OVS_TRY_WRLOCK(RETVAL, ...) \
+ __attribute__((exclusive_trylock_function(RETVAL, __VA_ARGS__)))
+#define OVS_TRY_RDLOCK(RETVAL, ...) \
+ __attribute__((shared_trylock_function(RETVAL, __VA_ARGS__)))
+#define OVS_TRY_LOCK(RETVAL, ...) \
+ __attribute__((exclusive_trylock_function(RETVAL, __VA_ARGS__)))
+#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.
*
- * Since sparse ignores MUTEX, it need not be an actual mutex. It can be
- * any construct on which paired acquire and release semantics make sense:
- * read/write locks, temporary memory allocations, whatever.
+ * Change the thread-safety check annotations to use "context" attribute.
*
- * OVS_ACQUIRE, OVS_RELEASE, and OVS_HOLDS are suitable for use within macros,
+ * OVS_MACRO_LOCK and OVS_MACRO_RELEASE are suitable for use within macros,
* where there is no function prototype to annotate. */
-#define OVS_ACQUIRES(MUTEX) __attribute__((context(MUTEX, 0, 1)))
-#define OVS_RELEASES(MUTEX) __attribute__((context(MUTEX, 1, 0)))
-#define OVS_MUST_HOLD(MUTEX) __attribute__((context(MUTEX, 1, 1)))
-#define OVS_ACQUIRE(MUTEX) __context__(MUTEX, 0, 1)
-#define OVS_RELEASE(MUTEX) __context__(MUTEX, 1, 0)
-#define OVS_HOLDS(MUTEX) __context__(MUTEX, 1, 1)
+#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_ACQUIRES(MUTEX)
-#define OVS_RELEASES(MUTEX)
-#define OVS_MUST_HOLD(MUTEX)
-#define OVS_ACQUIRE(MUTEX)
-#define OVS_RELEASE(MUTEX)
-#define OVS_HOLDS(MUTEX)
+#define OVS_LOCKABLE
+#define OVS_REQ_RDLOCK(...)
+#define OVS_ACQ_RDLOCK(...)
+#define OVS_REQ_WRLOCK(...)
+#define OVS_ACQ_WRLOCK(...)
+#define OVS_REQUIRES(...)
+#define OVS_ACQUIRES(...)
+#define OVS_TRY_WRLOCK(...)
+#define OVS_TRY_RDLOCK(...)
+#define OVS_TRY_LOCK(...)
+#define OVS_GUARDED
+#define OVS_GUARDED_BY(...)
+#define OVS_RELEASES(...)
+#define OVS_MACRO_LOCK(...)
+#define OVS_MACRO_RELEASE(...)
#endif
/* ISO C says that a C implementation may choose any integer type for an enum
git://git.onelab.eu / sliver-openvswitch.git / blobdiff