Filling cache values on cvar write

Instead of on read. Once it's in the inline cache we never have to make
one again. We want to eventually put the value into the cache, and the
best opportunity to do that is when you write the value.

1 files changed, 38 insertions, 7 deletions

diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 0aeab30077..72c90a8a5c 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -1286,7 +1286,7 @@ vm_getclassvariable(const rb_iseq_t *iseq, const rb_cref_t *cref, const rb_contr
 {
     if (ic->entry && ic->entry->global_cvar_state == GET_GLOBAL_CVAR_STATE()) {
         VALUE v = Qundef;
-        RB_DEBUG_COUNTER_INC(cvar_inline_hit);
+        RB_DEBUG_COUNTER_INC(cvar_read_inline_hit);
 
         if (st_lookup(RCLASS_IV_TBL(ic->entry->class_value), (st_data_t)id, &v)) {
             return v;
@@ -1298,6 +1298,10 @@ vm_getclassvariable(const rb_iseq_t *iseq, const rb_cref_t *cref, const rb_contr
 
     VALUE cvar_value = rb_cvar_find(klass, id, &defined_class);
 
+    if (RB_TYPE_P(defined_class, T_ICLASS)) {
+        defined_class = RBASIC(defined_class)->klass;
+    }
+
     struct rb_id_table *rb_cvc_tbl = RCLASS_CVC_TBL(defined_class);
 
     if (!rb_cvc_tbl) {
@@ -1307,11 +1311,7 @@ vm_getclassvariable(const rb_iseq_t *iseq, const rb_cref_t *cref, const rb_contr
     struct rb_cvar_class_tbl_entry *ent;
 
     if (!rb_id_table_lookup(rb_cvc_tbl, id, (VALUE*)&ent)) {
-        ent = ALLOC(struct rb_cvar_class_tbl_entry);
-        ent->class_value = defined_class;
-        ent->global_cvar_state = GET_GLOBAL_CVAR_STATE();
-        rb_id_table_insert(rb_cvc_tbl, id, (VALUE)ent);
-        RB_DEBUG_COUNTER_INC(cvar_inline_miss);
+        rb_bug("should have cvar cache entry");
     } else {
         ent->global_cvar_state = GET_GLOBAL_CVAR_STATE();
     }
@@ -1323,11 +1323,42 @@ vm_getclassvariable(const rb_iseq_t *iseq, const rb_cref_t *cref, const rb_contr
 }
 
 static inline void
-vm_setclassvariable(const rb_cref_t *cref, const rb_control_frame_t *cfp, ID id, VALUE val)
+vm_setclassvariable(const rb_iseq_t *iseq, const rb_cref_t *cref, const rb_control_frame_t *cfp, ID id, VALUE val, ICVARC ic)
 {
+    if (ic->entry && ic->entry->global_cvar_state == GET_GLOBAL_CVAR_STATE()) {
+        RB_DEBUG_COUNTER_INC(cvar_write_inline_hit);
+
+        rb_class_ivar_set(ic->entry->class_value, id, val);
+        return;
+    }
+
     VALUE klass = vm_get_cvar_base(cref, cfp, 1);
 
     rb_cvar_set(klass, id, val);
+
+    VALUE defined_class = 0;
+    rb_cvar_find(klass, id, &defined_class);
+
+    if (RB_TYPE_P(defined_class, T_ICLASS)) {
+        defined_class = RBASIC(defined_class)->klass;
+    }
+
+    struct rb_id_table *rb_cvc_tbl = RCLASS_CVC_TBL(defined_class);
+
+    if (!rb_cvc_tbl) {
+        rb_bug("the cvc table should be set");
+    }
+
+    struct rb_cvar_class_tbl_entry *ent;
+
+    if (!rb_id_table_lookup(rb_cvc_tbl, id, (VALUE*)&ent)) {
+        rb_bug("should have cvar cache entry");
+    } else {
+        ent->global_cvar_state = GET_GLOBAL_CVAR_STATE();
+    }
+
+    ic->entry = ent;
+    RB_OBJ_WRITTEN(iseq, Qundef, ent->class_value);
 }
 
 static inline VALUE