sync enc_table and rb_encoding_list

enc_table which manages Encoding information. rb_encoding_list
also manages Encoding objects. Both are accessed/modified by ractors
simultaneously so that they should be synchronized.

For enc_table, this patch introduced GLOBAL_ENC_TABLE_ENTER/LEAVE/EVAL
to access this table with VM lock. To make shortcut, three new global
variables global_enc_ascii, global_enc_utf_8, global_enc_us_ascii are
also introduced.

For rb_encoding_list, we split it to rb_default_encoding_list (256 entries)
and rb_additional_encoding_list. rb_default_encoding_list is fixed sized Array
so we don't need to synchronized (and most of apps only needs it). To manage
257 or more encoding objects, they are stored into rb_additional_encoding_list.
To access rb_additional_encoding_list., VM lock is needed.

1 files changed, 14 insertions, 0 deletions

diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
index 9e90d95274..05139e2081 100644
--- a/bootstraptest/test_ractor.rb
+++ b/bootstraptest/test_ractor.rb
@@ -780,4 +780,18 @@ assert_equal "#{N}#{N}", %Q{
   }.map{|r| r.take}.join
 }
 
+assert_equal "#{N/10}", %Q{
+  Ractor.new do
+    loop do
+      Encoding.find("test-enc-#{rand(5_000)}").inspect
+    rescue ArgumentError => e
+    end
+  end
+
+  src = Encoding.find("UTF-8")
+  #{N/10}.times{|i|
+    src.replicate("test-enc-\#{i}")
+  }
+}
+
 end # if !ENV['GITHUB_WORKFLOW']