YJIT: handle when all counters are zero in printout code

Also filter with not equal to zero instead of greater than zero, in case
there is memory corruption and counters are negative.

Fixes Shopify/ruby#70

1 files changed, 6 insertions, 1 deletions

diff --git a/ujit.rb b/ujit.rb
index a2f61b1021..d27d200daf 100644
--- a/ujit.rb
+++ b/ujit.rb
@@ -67,9 +67,14 @@ module UJIT
     def print_counters(counters, prefix:, prompt:)
       $stderr.puts(prompt)
       counters = counters.filter { |key, _| key.start_with?(prefix) }
-      counters.filter! { |_, value| value > 0 }
+      counters.filter! { |_, value| value != 0 }
       counters.transform_keys! { |key| key.to_s.delete_prefix(prefix) }
 
+      if counters.empty?
+        $stderr.puts("    (all relevant counters are zero)")
+        return
+      end
+
       counters = counters.to_a
       counters.sort_by! { |(_, counter_value)| counter_value }
       longest_name_length = counters.max_by { |(name, _)| name.length }.first.length