[PATCH 2/2] trace-cmd: Add ftrace options with fgraph retval option

[Jianfeng Wang <jianfeng.w.wang@oracle.com>]

Added internal options for ftrace, and included a fgraph:retval
option that will print the function names at the function exit.
When the option is set and the function_graph retval feature is
supported by the kernel, each function's return value will be
printed as '(ret=retval)'.

Signed-off-by: Jianfeng Wang <jianfeng.w.wang@oracle.com>
---
 lib/trace-cmd/trace-ftrace.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/trace-cmd/trace-ftrace.c b/lib/trace-cmd/trace-ftrace.c
index cb05d88c..fecc3d69 100644
--- a/lib/trace-cmd/trace-ftrace.c
+++ b/lib/trace-cmd/trace-ftrace.c
@@ -23,6 +23,12 @@ struct tep_plugin_option trace_ftrace_options[] = {
 		.description =
 		"Show the depth of each entry",
 	},
+	{
+		.name = "retval",
+		.plugin_alias = "fgraph",
+		.description =
+		"Print function retval at function exit in function graph",
+	},
 	{
 		.name = NULL,
 	}
@@ -30,6 +36,7 @@ struct tep_plugin_option trace_ftrace_options[] = {
 
 static struct tep_plugin_option *fgraph_tail = &trace_ftrace_options[0];
 static struct tep_plugin_option *fgraph_depth = &trace_ftrace_options[1];
+static struct tep_plugin_option *fgraph_retval = &trace_ftrace_options[2];
 
 static int find_ret_event(struct tracecmd_ftrace *finfo, struct tep_handle *pevent)
 {
@@ -232,7 +239,7 @@ print_graph_entry_leaf(struct trace_seq *s,
 		ret = trace_seq_printf(s, " (%lld)", depth);
 
 	/* Return Value */
-	if (ret && fgraph_retval_supported)
+	if (ret && fgraph_retval->set && fgraph_retval_supported)
 		ret = trace_seq_printf(s, " (ret=%lld)", retval);
 
 	return ret;
@@ -378,7 +385,7 @@ fgraph_ret_handler(struct trace_seq *s, struct tep_record *record,
 		trace_seq_printf(s, " (%lld)", depth);
 
 	/* Return Value */
-	if (fgraph_retval_supported)
+	if (fgraph_retval->set && fgraph_retval_supported)
 		trace_seq_printf(s, " (ret=%lld)", retval);
 
 	return 0;
-- 
2.42.1