+#if defined(TRACEPOINT_DEFINE) || defined(TRACEPOINT_CREATE_PROBES)
+
+/*
+ * 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).
+ */
+int __tracepoint_registered
+ __attribute__((weak, visibility("hidden")));
+int __tracepoint_ptrs_registered
+ __attribute__((weak, visibility("hidden")));
+struct tracepoint_dlopen tracepoint_dlopen
+ __attribute__((weak, visibility("hidden")));
+
+#ifndef _LGPL_SOURCE
+static inline void lttng_ust_notrace
+__tracepoint__init_urcu_sym(void);
+static inline void
+__tracepoint__init_urcu_sym(void)
+{
+ /*
+ * Symbols below are needed by tracepoint call sites and probe
+ * providers.
+ */
+ if (!tracepoint_dlopen.rcu_read_lock_sym_bp)
+ tracepoint_dlopen.rcu_read_lock_sym_bp =
+ URCU_FORCE_CAST(void (*)(void),
+ dlsym(tracepoint_dlopen.liblttngust_handle,
+ "tp_rcu_read_lock_bp"));
+ if (!tracepoint_dlopen.rcu_read_unlock_sym_bp)
+ tracepoint_dlopen.rcu_read_unlock_sym_bp =
+ URCU_FORCE_CAST(void (*)(void),
+ dlsym(tracepoint_dlopen.liblttngust_handle,
+ "tp_rcu_read_unlock_bp"));
+ if (!tracepoint_dlopen.rcu_dereference_sym_bp)
+ tracepoint_dlopen.rcu_dereference_sym_bp =
+ URCU_FORCE_CAST(void *(*)(void *p),
+ dlsym(tracepoint_dlopen.liblttngust_handle,
+ "tp_rcu_dereference_sym_bp"));
+}
+#else
+static inline void lttng_ust_notrace
+__tracepoint__init_urcu_sym(void);
+static inline void
+__tracepoint__init_urcu_sym(void)
+{
+}
+#endif
+
+static void lttng_ust_notrace __attribute__((constructor))
+__tracepoints__init(void);
+static void
+__tracepoints__init(void)
+{
+ if (__tracepoint_registered++)
+ return;
+
+ if (!tracepoint_dlopen.liblttngust_handle)
+ tracepoint_dlopen.liblttngust_handle =
+ dlopen("liblttng-ust-tracepoint.so.0", RTLD_NOW | RTLD_GLOBAL);
+ if (!tracepoint_dlopen.liblttngust_handle)
+ return;
+ __tracepoint__init_urcu_sym();
+}
+
+static void lttng_ust_notrace __attribute__((destructor))
+__tracepoints__destroy(void);
+static void
+__tracepoints__destroy(void)
+{
+ int ret;
+
+ if (--__tracepoint_registered)
+ return;
+ if (tracepoint_dlopen.liblttngust_handle && !__tracepoint_ptrs_registered) {
+ ret = dlclose(tracepoint_dlopen.liblttngust_handle);
+ if (ret) {
+ fprintf(stderr, "Error (%d) in dlclose\n", ret);
+ abort();
+ }
+ memset(&tracepoint_dlopen, 0, sizeof(tracepoint_dlopen));
+ }
+}
+
+#endif
+