X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Ftestpoint%2Ftestpoint.h;fp=src%2Fcommon%2Ftestpoint%2Ftestpoint.h;h=ba3af8a5370a7c6155e46e480b105fc16e2f2a15;hb=6242251b39f531a2485b758edcb455e220267fdd;hp=0000000000000000000000000000000000000000;hpb=db8870edf473e2a2f69e488375d32405ea324017;p=lttng-tools.git

diff --git a/src/common/testpoint/testpoint.h b/src/common/testpoint/testpoint.h
new file mode 100644
index 000000000..ba3af8a53
--- /dev/null
+++ b/src/common/testpoint/testpoint.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2012 - Christian Babeux <christian.babeux@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifdef NTESTPOINT
+
+#define testpoint(name)
+#define TESTPOINT_DECL(name)
+
+#else /* NTESTPOINT */
+
+#include <urcu.h> /* for caa_likely/unlikely */
+
+extern int lttng_testpoint_activated;
+
+void *lttng_testpoint_lookup(const char *name);
+
+/*
+ * Testpoint is only active if the global lttng_testpoint_activated flag is
+ * set.
+ */
+#define testpoint(name)					\
+	do {							\
+		if (caa_unlikely(lttng_testpoint_activated)) {	\
+			__testpoint_##name##_wrapper();		\
+		}						\
+	} while (0)
+
+/*
+ * One wrapper per testpoint is generated. This is to keep track of the symbol
+ * lookup status and the corresponding function pointer, if any.
+ */
+#define _TESTPOINT_DECL(_name)						\
+	static inline void __testpoint_##_name##_wrapper(void)		\
+	{								\
+		static void (*tp)(void);				\
+		static int found;					\
+		const char *tp_name = "__testpoint_" #_name;		\
+									\
+		if (tp) {						\
+			tp();						\
+		} else {						\
+			if (!found) {					\
+				tp = lttng_testpoint_lookup(tp_name);	\
+				if (tp) {				\
+					found = 1;			\
+					tp();				\
+				} else {				\
+					found = -1;			\
+				}					\
+			}						\
+		}							\
+	}
+
+/* Testpoint declaration */
+#define TESTPOINT_DECL(name)	\
+	_TESTPOINT_DECL(name)
+
+#endif /* NTESTPOINT */