diff --git a/clang/docs/ThreadSafetyAnalysis.rst b/clang/docs/ThreadSafetyAnalysis.rst
--- a/clang/docs/ThreadSafetyAnalysis.rst
+++ b/clang/docs/ThreadSafetyAnalysis.rst
@@ -209,21 +209,21 @@
   }
 
 
-ACQUIRE(...), ACQUIRE_SHARED(...), RELEASE(...), RELEASE_SHARED(...)
---------------------------------------------------------------------
+ACQUIRE(...), ACQUIRE_SHARED(...), RELEASE(...), RELEASE_SHARED(...), RELEASE_GENERIC(...)
+------------------------------------------------------------------------------------------
 
 *Previously*: ``EXCLUSIVE_LOCK_FUNCTION``, ``SHARED_LOCK_FUNCTION``,
 ``UNLOCK_FUNCTION``
 
-``ACQUIRE`` is an attribute on functions or methods, which
-declares that the function acquires a capability, but does not release it.  The
-caller must not hold the given capability on entry, and it will hold the
-capability on exit.  ``ACQUIRE_SHARED`` is similar.
+``ACQUIRE`` and ``ACQUIRE_SHARED`` are attributes on functions or methods
+declaring that the function acquires a capability, but does not release it.
+The given capability must not be held on entry, and will be held on exit
+(exclusively for ``ACQUIRE``, shared for ``ACQUIRE_SHARED``).
 
-``RELEASE`` and ``RELEASE_SHARED`` declare that the function releases the given
-capability.  The caller must hold the capability on entry, and will no longer
-hold it on exit. It does not matter whether the given capability is shared or
-exclusive.
+``RELEASE``, ``RELEASE_SHARED``, and ``RELEASE_GENERIC`` declare that the
+function releases the given capability.  The capability must be held on entry
+(exclusively for ``RELEASE``, shared for ``RELEASE_SHARED``, exclusively or
+shared for ``RELEASE_GENERIC``), and will no longer be held on exit.
 
 .. code-block:: c++
 
@@ -820,6 +820,9 @@
   #define RELEASE_SHARED(...) \
     THREAD_ANNOTATION_ATTRIBUTE__(release_shared_capability(__VA_ARGS__))
 
+  #define RELEASE_GENERIC(...) \
+    THREAD_ANNOTATION_ATTRIBUTE__(release_generic_capability(__VA_ARGS__))
+
   #define TRY_ACQUIRE(...) \
     THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_capability(__VA_ARGS__))
 
@@ -864,6 +867,9 @@
     // Release/unlock a shared mutex.
     void ReaderUnlock() RELEASE_SHARED();
 
+    // Generic unlock, can unlock exclusive and shared mutexes.
+    void GenericUnlock() RELEASE_GENERIC();
+
     // Try to acquire the mutex.  Returns true on success, and false on failure.
     bool TryLock() TRY_ACQUIRE(true);
 
diff --git a/clang/test/SemaCXX/thread-safety-annotations.h b/clang/test/SemaCXX/thread-safety-annotations.h
--- a/clang/test/SemaCXX/thread-safety-annotations.h
+++ b/clang/test/SemaCXX/thread-safety-annotations.h
@@ -6,6 +6,7 @@
 #define ASSERT_SHARED_LOCK(...)         __attribute__((assert_shared_capability(__VA_ARGS__)))
 #define EXCLUSIVE_LOCK_FUNCTION(...)    __attribute__((acquire_capability(__VA_ARGS__)))
 #define SHARED_LOCK_FUNCTION(...)       __attribute__((acquire_shared_capability(__VA_ARGS__)))
+#define UNLOCK_FUNCTION(...)            __attribute__((release_generic_capability(__VA_ARGS__)))
 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((try_acquire_capability(__VA_ARGS__)))
 #define SHARED_TRYLOCK_FUNCTION(...)    __attribute__((try_acquire_shared_capability(__VA_ARGS__)))
 #define EXCLUSIVE_LOCKS_REQUIRED(...)   __attribute__((requires_capability(__VA_ARGS__)))
@@ -16,6 +17,7 @@
 #define ASSERT_SHARED_LOCK(...)         __attribute__((assert_shared_lock(__VA_ARGS__)))
 #define EXCLUSIVE_LOCK_FUNCTION(...)    __attribute__((exclusive_lock_function(__VA_ARGS__)))
 #define SHARED_LOCK_FUNCTION(...)       __attribute__((shared_lock_function(__VA_ARGS__)))
+#define UNLOCK_FUNCTION(...)            __attribute__((unlock_function(__VA_ARGS__)))
 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((exclusive_trylock_function(__VA_ARGS__)))
 #define SHARED_TRYLOCK_FUNCTION(...)    __attribute__((shared_trylock_function(__VA_ARGS__)))
 #define EXCLUSIVE_LOCKS_REQUIRED(...)   __attribute__((exclusive_locks_required(__VA_ARGS__)))
@@ -23,7 +25,6 @@
 #endif
 
 // Lock semantics only
-#define UNLOCK_FUNCTION(...)            __attribute__((unlock_function(__VA_ARGS__)))
 #define GUARDED_VAR                     __attribute__((guarded_var))
 #define PT_GUARDED_VAR                  __attribute__((pt_guarded_var))