[PATCH] libtracefs: Have labels in selections be synthetic fields

[Steven Rostedt <rostedt@goodmis.org>]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

The labels in the selection case are suppose to be the fields for the
created synthetic events. But for some reason they were ignored.

For example:

  sqlhist -n wakeup_lat 'select end.next_pid as pid, end.next_comm as comm, (end.TIMESTAMP - start.TIMESTAMP) as lat
   from sched_waking as start join sched_switch as end on start.pid = end.next_pid'

Produces the synthetic event of:

  echo 'wakeup_lat pid_t next_pid; char next_comm[16]; u64 lat;' >> /sys/kernel/tracing/synthetic_events

Where it should have used 'pid' instead of 'next_pid' and 'comm' instead
of 'next_comm'

Fixes: 25446407 ("libtracefs: Added new API tracefs_sql()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 src/tracefs-sqlhist.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
index 9811362..8d71800 100644
--- a/src/tracefs-sqlhist.c
+++ b/src/tracefs-sqlhist.c
@@ -253,6 +253,7 @@ __hidden int add_selection(struct sqlhist_bison *sb, void *select,
 
 	switch (expr->type) {
 	case EXPR_FIELD:
+		expr->field.label = name;
 		break;
 	case EXPR_COMPARE:
 		expr->compare.name = name;
-- 
2.35.1