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, 11 insertions, 0 deletions

diff --git a/iseq.c b/iseq.c
index 4a67ee19d8..096d456f11 100644
--- a/iseq.c
+++ b/iseq.c
@@ -182,6 +182,17 @@ iseq_extract_values(VALUE *code, size_t pos, iseq_value_itr_t * func, void *data
               }
             }
             break;
+          case TS_IC:
+            {
+                IC ic = (IC)code[pos + op_no + 1];
+                if (ic->entry) {
+                    VALUE nv = func(data, (VALUE)ic->entry);
+                    if ((VALUE)ic->entry != nv) {
+                        ic->entry = (void *)nv;
+                    }
+                }
+            }
+            break;
           case TS_IVC:
             {
                 IVC ivc = (IVC)code[pos + op_no + 1];