YJIT: Fix raw sample stack lengths in exit traces (#7728)

yjit-trace-exits appends a synthetic sample for the instruction being
exited, but we didn't increment the size of the stack. Fixing this count
correctly lets us successfully generate a flamegraph from the exits.

I also replaced the line number for instructions with 0, as I don't
think the previous value had meaning.

Co-authored-by: Adam Hess <[email protected]>

1 files changed, 3 insertions, 2 deletions

diff --git a/yjit.c b/yjit.c
index 2d3b7c9e9d..72d01d78f4 100644
--- a/yjit.c
+++ b/yjit.c
@@ -186,8 +186,9 @@ rb_yjit_exit_locations_dict(VALUE *yjit_raw_samples, int *yjit_line_samples, int
         int line_num = (int)yjit_line_samples[idx];
         idx++;
 
-        rb_ary_push(raw_samples, SIZET2NUM(num));
-        rb_ary_push(line_samples, INT2NUM(line_num));
+        // + 1 as we append an additional sample for the insn
+        rb_ary_push(raw_samples, SIZET2NUM(num + 1));
+        rb_ary_push(line_samples, INT2NUM(line_num + 1));
 
         // Loop through the length of samples_len and add data to the
         // frames hash. Also push the current value onto the raw_samples