Introduce disposable call-cache.

This patch contains several ideas:

(1) Disposable inline method cache (IMC) for race-free inline method cache
    * Making call-cache (CC) as a RVALUE (GC target object) and allocate new
      CC on cache miss.
    * This technique allows race-free access from parallel processing
      elements like RCU.
(2) Introduce per-Class method cache (pCMC)
    * Instead of fixed-size global method cache (GMC), pCMC allows flexible
      cache size.
    * Caching CCs reduces CC allocation and allow sharing CC's fast-path
      between same call-info (CI) call-sites.
(3) Invalidate an inline method cache by invalidating corresponding method
    entries (MEs)
    * Instead of using class serials, we set "invalidated" flag for method
      entry itself to represent cache invalidation.
    * Compare with using class serials, the impact of method modification
      (add/overwrite/delete) is small.
    * Updating class serials invalidate all method caches of the class and
      sub-classes.
    * Proposed approach only invalidate the method cache of only one ME.

See [Feature #16614] for more details.

1 files changed, 4 insertions, 11 deletions

diff --git a/vm_insnhelper.h b/vm_insnhelper.h
index e9337b82a8..07b38ea9d9 100644
--- a/vm_insnhelper.h
+++ b/vm_insnhelper.h
@@ -121,20 +121,13 @@ enum vm_regan_acttype {
  */
 
 static inline void
-CC_SET_FASTPATH(CALL_CACHE cc, vm_call_handler func, bool enabled)
+CC_SET_FASTPATH(const struct rb_callcache *cc, vm_call_handler func, bool enabled)
 {
     if (LIKELY(enabled)) {
-        cc->call = func;
+        vm_cc_call_set(cc, func);
     }
 }
 
-static inline void
-CC_SET_ME(CALL_CACHE cc, const rb_callable_method_entry_t *me)
-{
-    cc->me = me;
-    cc->method_serial = me ? me->def->method_serial : 0;
-}
-
 #define GET_BLOCK_HANDLER() (GET_LEP()[VM_ENV_DATA_INDEX_SPECVAL])
 
 /**********************************************************/
@@ -258,10 +251,10 @@ THROW_DATA_CONSUMED_SET(struct vm_throw_data *obj)
 /* If this returns true, an optimized function returned by `vm_call_iseq_setup_func`
    can be used as a fastpath. */
 static bool
-vm_call_iseq_optimizable_p(const struct rb_callinfo *ci, const struct rb_call_cache *cc)
+vm_call_iseq_optimizable_p(const struct rb_callinfo *ci, const struct rb_callcache *cc)
 {
     return !IS_ARGS_SPLAT(ci) && !IS_ARGS_KEYWORD(ci) &&
-        !(METHOD_ENTRY_VISI(cc->me) == METHOD_VISI_PROTECTED);
+        !(METHOD_ENTRY_VISI(vm_cc_cme(cc)) == METHOD_VISI_PROTECTED);
 }
 
 #endif /* RUBY_INSNHELPER_H */