[lttng-dev] [PATCH babeltrace stable-1.5 5/5] Add empty plug-in hooks to prevent their elimination by the linker

[Michael Jeanson]

From: Jérémie Galarneau <jeremie.galarneau at efficios.com>

Signed-off-by: Jérémie Galarneau <jeremie.galarneau at efficios.com>
---
 converter/babeltrace.c                 | 17 +++++++++++++++++
 formats/bt-dummy/bt-dummy.c            |  8 ++++++++
 formats/ctf-metadata/ctf-metadata.c    |  8 ++++++++
 formats/ctf-text/ctf-text.c            |  8 ++++++++
 formats/ctf/ctf.c                      |  8 ++++++++
 formats/lttng-live/lttng-live-plugin.c |  8 ++++++++
 6 files changed, 57 insertions(+)

diff --git a/converter/babeltrace.c b/converter/babeltrace.c
index 2e4003c..f74384e 100644
--- a/converter/babeltrace.c
+++ b/converter/babeltrace.c
@@ -76,6 +76,12 @@ static int opt_stream_intersection;
 
 static struct bt_format *fmt_read;
 
+void bt_dummy_hook(void);
+void bt_lttng_live_hook(void);
+void bt_ctf_hook(void);
+void bt_ctf_text_hook(void);
+void bt_ctf_metadata_hook(void);
+
 static
 void strlower(char *str)
 {
@@ -703,6 +709,15 @@ error_iter:
 	return ret;
 }
 
+void call_plugins_hooks(void)
+{
+	bt_dummy_hook();
+	bt_lttng_live_hook();
+	bt_ctf_hook();
+	bt_ctf_text_hook();
+	bt_ctf_metadata_hook();
+}
+
 int main(int argc, char **argv)
 {
 	int ret, partial_error = 0, open_success = 0;
@@ -711,6 +726,8 @@ int main(int argc, char **argv)
 	struct bt_context *ctx;
 	int i;
 
+	call_plugins_hooks();
+
 	opt_input_paths = g_ptr_array_new();
 
 	ret = parse_options(argc, argv);
diff --git a/formats/bt-dummy/bt-dummy.c b/formats/bt-dummy/bt-dummy.c
index 6192e88..65f2308 100644
--- a/formats/bt-dummy/bt-dummy.c
+++ b/formats/bt-dummy/bt-dummy.c
@@ -38,6 +38,14 @@
 #include <unistd.h>
 #include <stdlib.h>
 
+void bt_dummy_hook(void)
+{
+	/*
+	 * Dummy function to prevent the linker from discarding this format as
+	 * "unused" in static builds.
+	 */
+}
+
 static
 int bt_dummy_write_event(struct bt_stream_pos *ppos, struct ctf_stream_definition *stream)
 {
diff --git a/formats/ctf-metadata/ctf-metadata.c b/formats/ctf-metadata/ctf-metadata.c
index a5a74c3..a47fd36 100644
--- a/formats/ctf-metadata/ctf-metadata.c
+++ b/formats/ctf-metadata/ctf-metadata.c
@@ -54,6 +54,14 @@ struct bt_format ctf_metadata_format = {
 	.close_trace = ctf_metadata_close_trace,
 };
 
+void bt_ctf_metadata_hook(void)
+{
+	/*
+	 * Dummy function to prevent the linker from discarding this format as
+	 * "unused" in static builds.
+	 */
+}
+
 static
 int ctf_metadata_trace_pre_handler(struct bt_stream_pos *ppos,
 			struct bt_trace_descriptor *td)
diff --git a/formats/ctf-text/ctf-text.c b/formats/ctf-text/ctf-text.c
index cc22336..017f311 100644
--- a/formats/ctf-text/ctf-text.c
+++ b/formats/ctf-text/ctf-text.c
@@ -139,6 +139,14 @@ struct ctf_callsite_dups *ctf_trace_callsite_lookup(struct ctf_trace *trace,
 			(gpointer) (unsigned long) callsite_name);
 }
 
+void bt_ctf_text_hook(void)
+{
+	/*
+	 * Dummy function to prevent the linker from discarding this format as
+	 * "unused" in static builds.
+	 */
+}
+
 int print_field(struct bt_definition *definition)
 {
 	/* Print all fields in verbose mode */
diff --git a/formats/ctf/ctf.c b/formats/ctf/ctf.c
index 324b9f8..d6d078f 100644
--- a/formats/ctf/ctf.c
+++ b/formats/ctf/ctf.c
@@ -157,6 +157,14 @@ struct bt_format ctf_format = {
 	.convert_index_timestamp = ctf_convert_index_timestamp,
 };
 
+void bt_ctf_hook(void)
+{
+	/*
+	 * Dummy function to prevent the linker from discarding this format as
+	 * "unused" in static builds.
+	 */
+}
+
 static
 uint64_t ctf_timestamp_begin(struct bt_trace_descriptor *descriptor,
 		struct bt_trace_handle *handle, enum bt_clock_type type)
diff --git a/formats/lttng-live/lttng-live-plugin.c b/formats/lttng-live/lttng-live-plugin.c
index a1fbb9e..dfabb98 100644
--- a/formats/lttng-live/lttng-live-plugin.c
+++ b/formats/lttng-live/lttng-live-plugin.c
@@ -41,6 +41,14 @@
 
 static volatile int should_quit;
 
+void bt_lttng_live_hook(void)
+{
+	/*
+	 * Dummy function to prevent the linker from discarding this format as
+	 * "unused" in static builds.
+	 */
+}
+
 int lttng_live_should_quit(void)
 {
 	return should_quit;
-- 
2.7.4