enable constant cache on ractors

constant cache `IC` is accessed by non-atomic manner and there are
thread-safety issues, so Ruby 3.0 disables to use const cache on
non-main ractors.

This patch enables it by introducing `imemo_constcache` and allocates
it by every re-fill of const cache like `imemo_callcache`.
[Bug #17510]

Now `IC` only has one entry `IC::entry` and it points to
`iseq_inline_constant_cache_entry`, managed by T_IMEMO object.

`IC` is atomic data structure so `rb_mjit_before_vm_ic_update()` and
`rb_mjit_after_vm_ic_update()` is not needed.

1 files changed, 1 insertions, 0 deletions

diff --git a/ext/objspace/objspace.c b/ext/objspace/objspace.c
index 0930e10e92..7afdfc1f6b 100644
--- a/ext/objspace/objspace.c
+++ b/ext/objspace/objspace.c
@@ -650,6 +650,7 @@ count_imemo_objects(int argc, VALUE *argv, VALUE self)
         imemo_type_ids[10] = rb_intern("imemo_parser_strterm");
         imemo_type_ids[11] = rb_intern("imemo_callinfo");
         imemo_type_ids[12] = rb_intern("imemo_callcache");
+        imemo_type_ids[13] = rb_intern("imemo_constcache");
     }
 
     each_object_with_flags(count_imemo_objects_i, (void *)hash);