[lttng-dev] [Patch LTTng-ust 2/7] Add empty macros to support CTF named enumerations

[Geneviève Bastien]

The macros are initialized so that CTF enumerations can be used in tracepoints.
They do not do anything yet.

Signed-off-by: Geneviève Bastien <gbastien+lttng at versatic.net>
---
 include/lttng/tracepoint.h                   | 41 ++++++++++++++++++++++++++++
 include/lttng/ust-tracepoint-event-nowrite.h |  4 +++
 include/lttng/ust-tracepoint-event-reset.h   | 12 ++++++++
 include/lttng/ust-tracepoint-event-write.h   |  4 +++
 4 files changed, 61 insertions(+)

diff --git a/include/lttng/tracepoint.h b/include/lttng/tracepoint.h
index 66e2abd..be650b7 100644
--- a/include/lttng/tracepoint.h
+++ b/include/lttng/tracepoint.h
@@ -421,6 +421,47 @@ __tracepoints__ptrs_destroy(void)
 
 /* The following declarations must be outside re-inclusion protection. */
 
+#ifndef TRACEPOINT_ENUM
+
+/*
+ * Tracepoint Enumerations
+ *
+ * The enumeration is a mapping between an integer and a string. It can be used
+ * to have a more compact trace in cases where the possible values for a field
+ * are limited:
+ *
+ * An example:
+ *
+ * TRACEPOINT_ENUM(someproject_component, enumname, int
+ *	TP_ENUM_VALUES(
+ *		ctf_enum_value("even", 0)
+ *		ctf_enum_value("uneven", 1)
+ *		ctf_enum_range("twoto4", 2, 4)
+ *		ctf_enum_value("five", 5)
+ *	)
+ * )
+ *
+ * Where "someproject_component" is the name of the component this enumeration
+ * belongs to and "enumname" identifies this enumeration. The "int" is the data
+ * type of the container and can be anything that can be translated to a ctf
+ * integer (int, short, char, etc). Inside the TP_ENUM_VALUES macro is the
+ * actual mapping. Each string value can map to either a single value with
+ * ctf_enum_value or a range of values with ctf_enum_range.
+ *
+ * That enumeration can then be used in a field inside the TP_FIELD macro using
+ * the following line:
+ *
+ * ctf_enum(someproject_component, enumname, enumfield, enumval)
+ *
+ * Where "someproject_component" and "enumname" match those in the
+ * TRACEPOINT_ENUM, "enumfield" is the name of the field and "enumval" is the
+ * value.
+ */
+
+#define TRACEPOINT_ENUM(provider, name, type, values)
+
+#endif /* #ifndef TRACEPOINT_ENUM */
+
 #ifndef TRACEPOINT_EVENT
 
 /*
diff --git a/include/lttng/ust-tracepoint-event-nowrite.h b/include/lttng/ust-tracepoint-event-nowrite.h
index 98d9791..7f5b1d9 100644
--- a/include/lttng/ust-tracepoint-event-nowrite.h
+++ b/include/lttng/ust-tracepoint-event-nowrite.h
@@ -49,3 +49,7 @@
 #undef ctf_string_nowrite
 #define ctf_string_nowrite(_item, _src)				\
 	_ctf_string(_item, _src, 1)
+
+#undef ctf_enum_nowrite
+#define ctf_enum_nowrite(_provider, _name, _item, _src)		\
+	_ctf_enum(_provider, _name, _item, _src, 1)
diff --git a/include/lttng/ust-tracepoint-event-reset.h b/include/lttng/ust-tracepoint-event-reset.h
index 412883d..58e3428 100644
--- a/include/lttng/ust-tracepoint-event-reset.h
+++ b/include/lttng/ust-tracepoint-event-reset.h
@@ -28,6 +28,9 @@
 #undef TRACEPOINT_EVENT_INSTANCE
 #define TRACEPOINT_EVENT_INSTANCE(_provider, _template, _name, _args)
 
+#undef TRACEPOINT_ENUM
+#define TRACEPOINT_ENUM(_provider, _name, _type, _values)
+
 #undef TP_ARGS
 #define TP_ARGS(...)
 
@@ -61,6 +64,9 @@
 #undef _ctf_string
 #define _ctf_string(_item, _src, _nowrite)
 
+#undef _ctf_enum
+#define _ctf_enum(_provider, _name, _item, _src, _nowrite)
+
 /* "write" */
 #undef ctf_integer
 #define ctf_integer(_type, _item, _src)
@@ -92,6 +98,9 @@
 #undef ctf_string
 #define ctf_string(_item, _src)
 
+#undef ctf_enum
+#define ctf_enum(_provider, _name, _item, _src)
+
 /* "nowrite" */
 #undef ctf_integer_nowrite
 #define ctf_integer_nowrite(_type, _item, _src)
@@ -113,3 +122,6 @@
 
 #undef ctf_string_nowrite
 #define ctf_string_nowrite(_item, _src)
+
+#undef ctf_enum_nowrite
+#define ctf_enum_nowrite(_provider, _name, _item, _src)
diff --git a/include/lttng/ust-tracepoint-event-write.h b/include/lttng/ust-tracepoint-event-write.h
index 44218d2..7dd06ed 100644
--- a/include/lttng/ust-tracepoint-event-write.h
+++ b/include/lttng/ust-tracepoint-event-write.h
@@ -61,3 +61,7 @@
 #undef ctf_string
 #define ctf_string(_item, _src)					\
 	_ctf_string(_item, _src, 0)
+
+#undef ctf_enum
+#define ctf_enum(_provider, _name, _item, _src)			\
+	_ctf_enum(_provider, _name, _item, _src, 0)
-- 
1.8.5.3