Merge branch 'mainstream'

[sliver-openvswitch.git] / lib / compiler.h

diff --git a/lib/compiler.h b/lib/compiler.h
index 94a2218..ccc949b 100644 (file)
--- a/lib/compiler.h
+++ b/lib/compiler.h
@@ -20,6 +20,9 @@
 #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__))
@@ -65,6 +68,16 @@
  *      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
@@ -84,6 +97,7 @@
  *    - 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
@@ -115,30 +129,11 @@
 #define OVS_GUARDED_BY(...) __attribute__((guarded_by(__VA_ARGS__)))
 #define OVS_RELEASES(...) __attribute__((unlock_function(__VA_ARGS__)))
 #define OVS_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_EXCLUDED(...)
-#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_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(...)
@@ -153,8 +148,9 @@
 #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