X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;f=include%2Fust%2Ftracepoint.h;h=c484353dc28ffbc2475cc35e24b676f074bfc3bb;hb=4e2ee1f5ad0b837440f3b850e971f25db209cca1;hp=158d9b8a4cc1d3d28fdf4546f058dc8f83868152;hpb=d5001b43d4c8ec16fb926b7806a9ad1023a3140b;p=ust.git

diff --git a/include/ust/tracepoint.h b/include/ust/tracepoint.h
index 158d9b8..c484353 100644
--- a/include/ust/tracepoint.h
+++ b/include/ust/tracepoint.h
@@ -28,6 +28,10 @@
 #include <urcu-bp.h>
 #include <urcu/list.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct tracepoint_probe {
 	void *func;
 	void *data;
@@ -45,28 +49,6 @@ struct tracepoint {
  */
 #define tracepoint(name, args...)	__trace_##name(args)
 
-/*
- * Library should be made known to libust by declaring TRACEPOINT_LIB in
- * the source file. (Usually at the end of the file, in the outermost
- * scope).
- */
-#define TRACEPOINT_LIB							\
-	extern struct tracepoint * const __start___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
-	extern struct tracepoint * const __stop___tracepoints_ptrs[] __attribute__((weak, visibility("hidden"))); \
-	static struct tracepoint * __tracepoint_ptr_dummy		\
-	__attribute__((used, section("__tracepoints_ptrs")));		\
-	static void __attribute__((constructor)) __tracepoints__init(void) \
-	{								\
-		tracepoint_register_lib(__start___tracepoints_ptrs,	\
-					__stop___tracepoints_ptrs -	\
-					__start___tracepoints_ptrs);	\
-	}								\
-									\
-	static void __attribute__((destructor)) __tracepoints__destroy(void) \
-	{								\
-		tracepoint_unregister_lib(__start___tracepoints_ptrs);	\
-	}
-
 /*
  * it_func[0] is never NULL because there is at least one element in the array
  * when the array itself is non NULL.
@@ -83,7 +65,7 @@ struct tracepoint {
 			do {						\
 				__tp_it_func = __tp_it_probe_ptr->func;	\
 				__tp_cb_data = __tp_it_probe_ptr->data;	\
-				((void(*)(proto))__tp_it_func)(args);	\
+				URCU_FORCE_CAST(void(*)(proto), __tp_it_func)(args); \
 			} while ((++__tp_it_probe_ptr)->func);		\
 		}							\
 		rcu_read_unlock();					\
@@ -182,18 +164,39 @@ int __tracepoint_probe_register(const char *name, void *probe, void *data);
 extern
 int __tracepoint_probe_unregister(const char *name, void *probe, void *data);
 
-struct tracepoint_lib {
-	struct tracepoint * const *tracepoints_start;
-	int tracepoints_count;
-	struct cds_list_head list;
-};
-
 extern
 int tracepoint_register_lib(struct tracepoint * const *tracepoints_start,
 			    int tracepoints_count);
 extern
 int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
 
+/*
+ * These weak symbols, the constructor, and destructor take care of
+ * registering only _one_ instance of the tracepoints per shared-ojbect
+ * (or for the whole main program).
+ */
+extern struct tracepoint * const __start___tracepoints_ptrs[]
+	__attribute__((weak, visibility("hidden")));
+extern struct tracepoint * const __stop___tracepoints_ptrs[]
+	__attribute__((weak, visibility("hidden")));
+int __tracepoint_registered
+	__attribute__((weak, visibility("hidden")));
+
+static void __attribute__((constructor)) __tracepoints__init(void)
+{
+	if (__tracepoint_registered++)
+		return;
+	tracepoint_register_lib(__start___tracepoints_ptrs,
+				__stop___tracepoints_ptrs -
+				__start___tracepoints_ptrs);
+}
+
+static void __attribute__((destructor)) __tracepoints__destroy(void)
+{
+	if (--__tracepoint_registered)
+		return;
+	tracepoint_unregister_lib(__start___tracepoints_ptrs);
+}
 
 #ifndef TRACEPOINT_EVENT
 /*
@@ -233,6 +236,7 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
  *
  * Firstly, name your tracepoint via TRACEPOINT_EVENT(name,
  *
+ * The name should be a proper C99 identifier.
  * The "name" MUST follow these rules to ensure no namespace clash
  * occurs:
  *
@@ -328,6 +332,13 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
  *		ctf_integer(int, next_prio, next->prio)
  *	)
  * )
+ *
+ * Do _NOT_ add comma (,) nor semicolon (;) after the TRACEPOINT_EVENT
+ * declaration.
+ *
+ * The TRACEPOINT_SYSTEM must be defined when declaring a
+ * TRACEPOINT_EVENT. See ust/tracepoint-event.h for information about
+ * usage of other macros controlling TRACEPOINT_EVENT.
  */
 
 #define TRACEPOINT_EVENT(name, proto, args, fields)			\
@@ -349,4 +360,65 @@ int tracepoint_unregister_lib(struct tracepoint * const *tracepoints_start);
 
 #endif /* #ifndef TRACEPOINT_EVENT */
 
+#ifndef TRACEPOINT_LOGLEVEL
+
+/*
+ * Tracepoint Loglevel Declaration Facility
+ *
+ * This is a place-holder the tracepoint loglevel declaration,
+ * overridden by the tracer implementation.
+ *
+ * Typical use of these loglevels:
+ *
+ * 1) Declare the mapping between loglevel names and an integer values
+ *    within TRACEPOINT_LOGLEVEL_ENUM, using TP_LOGLEVEL for each tuple.
+ *    Do _NOT_ add comma (,) nor semicolon (;) between the
+ *    TRACEPOINT_LOGLEVEL_ENUM entries. Do _NOT_ add comma (,) nor
+ *    semicolon (;) after the TRACEPOINT_LOGLEVEL_ENUM declaration.  The
+ *    name should be a proper C99 identifier.
+ *
+ *      TRACEPOINT_LOGLEVEL_ENUM(
+ *              TP_LOGLEVEL( < loglevel_name >, < value > )
+ *              TP_LOGLEVEL( < loglevel_name >, < value > )
+ *              ...
+ *      )
+ *
+ *    e.g.:
+ *
+ *      TRACEPOINT_LOGLEVEL_ENUM(
+ *              TP_LOGLEVEL(LOG_EMERG,   0)
+ *              TP_LOGLEVEL(LOG_ALERT,   1)
+ *              TP_LOGLEVEL(LOG_CRIT,    2)
+ *              TP_LOGLEVEL(LOG_ERR,     3)
+ *              TP_LOGLEVEL(LOG_WARNING, 4)
+ *              TP_LOGLEVEL(LOG_NOTICE,  5)
+ *              TP_LOGLEVEL(LOG_INFO,    6)
+ *              TP_LOGLEVEL(LOG_DEBUG,   7)
+ *      )
+ *
+ * 2) Then, declare tracepoint loglevels for tracepoints. A
+ *    TRACEPOINT_EVENT should be declared prior to the the
+ *    TRACEPOINT_LOGLEVEL for a given tracepoint name. The first field
+ *    is the name of the tracepoint, the second field is the loglevel
+ *    name.
+ *
+ *      TRACEPOINT_LOGLEVEL(< [com_company_]project_[component_]event >,
+ *              < loglevel_name >)
+ *
+ * The TRACEPOINT_SYSTEM must be defined when declaring a
+ * TRACEPOINT_LOGLEVEL_ENUM and TRACEPOINT_LOGLEVEL. The tracepoint
+ * loglevel enumeration apply to the entire TRACEPOINT_SYSTEM. Only one
+ * tracepoint loglevel enumeration should be declared per tracepoint
+ * system.
+ */
+
+#define TRACEPOINT_LOGLEVEL_ENUM()
+#define TRACEPOINT_LOGLEVEL(name, loglevel)
+
+#endif /* #ifndef TRACEPOINT_LOGLEVEL */
+
+#ifdef __cplusplus 
+}
+#endif
+
 #endif /* _UST_TRACEPOINT_H */