per-method serial number

Methods and their definitions can be allocated/deallocated on-the-fly.
One pathological situation is when a method is deallocated then another
one is allocated immediately after that.  Address of those old/new method
entries/definitions can be the same then, depending on underlying
malloc/free implementation.

So pointer comparison is insufficient.  We have to check the contents.
To do so we introduce def->method_serial, which is an integer unique to
that specific method definition.

PS: Note that method_serial being uintptr_t rather than rb_serial_t is
intentional.  This is because rb_serial_t can be bigger than a pointer
on a 32bit system (rb_serial_t is at least 64bit).  In order to preserve
old packing of struct rb_call_cache, rb_serial_t is inappropriate.

1 files changed, 1 insertions, 1 deletions

diff --git a/vm_eval.c b/vm_eval.c
index cec1ea41f6..54a4036ae7 100644
--- a/vm_eval.c
+++ b/vm_eval.c
@@ -47,7 +47,7 @@ rb_vm_call0(rb_execution_context_t *ec, VALUE recv, ID id, int argc, const VALUE
 {
     struct rb_calling_info calling = { Qundef, recv, argc, kw_splat, };
     struct rb_call_info ci = { id, (kw_splat ? VM_CALL_KW_SPLAT : 0), argc, };
-    struct rb_call_cache cc = { 0, { 0, }, me, me->def, vm_call_general, { 0, }, };
+    struct rb_call_cache cc = { 0, { 0, }, me, me->def->method_serial, vm_call_general, { 0, }, };
     struct rb_call_data cd = { cc, ci, };
     return vm_call0_body(ec, &calling, &cd, argv);
 }