YJIT: Add ivar counter exits

On Rails we're seeing a lot of exits for ivars in the Active Record
tests. In trying to track them down it was hard to find what code is
exiting.

This change adds a counted exit for when an object is "megamorphic". In
these cases there are too many specializations in the Ruby code so YJIT
exits.

Co-authored-by: Aaron Patterson [email protected]

1 files changed, 1 insertions, 0 deletions

diff --git a/yjit.c b/yjit.c
index 0bf84f13b7..3354c24341 100644
--- a/yjit.c
+++ b/yjit.c
@@ -103,6 +103,7 @@ YJIT_DECLARE_COUNTERS(
 
     getivar_se_self_not_heap,
     getivar_idx_out_of_range,
+    getivar_megamorphic,
 
     setivar_se_self_not_heap,
     setivar_idx_out_of_range,