#include <stdbool.h>
/*
+ * A function-like feature checking macro that is a wrapper around
+ * `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a
+ * nonzero constant integer if the attribute is supported or 0 if not.
+ */
+#ifdef __has_attribute
+#define HAVE_ATTRIBUTE(x) __has_attribute(x)
+#else
+#define HAVE_ATTRIBUTE(x) 0
+#endif
+
+#if HAVE_ATTRIBUTE(guarded_by) && HAVE_ATTRIBUTE(pt_guarded_by) && \
+ HAVE_ATTRIBUTE(lockable) && HAVE_ATTRIBUTE(exclusive_lock_function) && \
+ HAVE_ATTRIBUTE(exclusive_trylock_function) && HAVE_ATTRIBUTE(exclusive_locks_required) && \
+ HAVE_ATTRIBUTE(no_thread_safety_analysis)
+
+/* Documents if a shared field or global variable needs to be protected by a mutex. */
+#define GUARDED_BY(x) __attribute__((guarded_by(x)))
+
+/*
+ * Documents if the memory location pointed to by a pointer should be guarded by
+ * a mutex when dereferencing the pointer.
+ */
+#define PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x)))
+
+/* Documents if a type is a lockable type. */
+#define LOCKABLE __attribute__((lockable))
+
+/* Documents functions that acquire a lock in the body of a function, and do not release it. */
+#define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__)))
+
+/*
+ * Documents functions that expect a lock to be held on entry to the function,
+ * and release it in the body of the function.
+ */
+#define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__)))
+
+/* Documents functions that try to acquire a lock, and return success or failure. */
+#define EXCLUSIVE_TRYLOCK_FUNCTION(...) \
+ __attribute__((exclusive_trylock_function(__VA_ARGS__)))
+
+/* Documents a function that expects a mutex to be held prior to entry. */
+#define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__)))
+
+/* Turns off thread safety checking within the body of a particular function. */
+#define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis))
+
+#else
+
+#define GUARDED_BY(x)
+#define PT_GUARDED_BY(x)
+#define LOCKABLE
+#define EXCLUSIVE_LOCK_FUNCTION(...)
+#define UNLOCK_FUNCTION(...)
+#define EXCLUSIVE_TRYLOCK_FUNCTION(...)
+#define EXCLUSIVE_LOCKS_REQUIRED(...)
+#define NO_THREAD_SAFETY_ANALYSIS
+
+#endif
+
+/*
* A wrapper around the mutex implementation that allows perf to error check
* usage, etc.
*/
-struct mutex {
+struct LOCKABLE mutex {
pthread_mutex_t lock;
};
void mutex_init_pshared(struct mutex *mtx);
void mutex_destroy(struct mutex *mtx);
-void mutex_lock(struct mutex *mtx);
-void mutex_unlock(struct mutex *mtx);
+void mutex_lock(struct mutex *mtx) EXCLUSIVE_LOCK_FUNCTION(*mtx);
+void mutex_unlock(struct mutex *mtx) UNLOCK_FUNCTION(*mtx);
/* Tries to acquire the lock and returns true on success. */
-bool mutex_trylock(struct mutex *mtx);
+bool mutex_trylock(struct mutex *mtx) EXCLUSIVE_TRYLOCK_FUNCTION(true, *mtx);
/* Default initialize the cond struct. */
void cond_init(struct cond *cnd);
void cond_init_pshared(struct cond *cnd);
void cond_destroy(struct cond *cnd);
-void cond_wait(struct cond *cnd, struct mutex *mtx);
+void cond_wait(struct cond *cnd, struct mutex *mtx) EXCLUSIVE_LOCKS_REQUIRED(mtx);
void cond_signal(struct cond *cnd);
void cond_broadcast(struct cond *cnd);