Embed small size array elements in the heap.

It reduces the memory consumption and sometimes improve the
performance as well.  For example, the consumed memory size
of `bench/bm_ao_render.rb` is reduced from 1.2GB to 1GB, and
its total execution time become 18.795 sec from 22.229 sec.

1 files changed, 13 insertions, 10 deletions

diff --git a/src/gc.c b/src/gc.c
index cad2a0a53..8cc8feb08 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -466,10 +466,13 @@ mrb_gc_unregister(mrb_state *mrb, mrb_value obj)
   }
   a = mrb_ary_ptr(table);
   mrb_ary_modify(mrb, a);
-  for (i = 0; i < a->len; i++) {
-    if (mrb_obj_eq(mrb, a->ptr[i], obj)) {
-      a->len--;
-      memmove(&a->ptr[i], &a->ptr[i + 1], (a->len - i) * sizeof(a->ptr[i]));
+  for (i = 0; i < ARY_LEN(a); i++) {
+    if (mrb_obj_eq(mrb, ARY_PTR(a)[i], obj)) {
+      mrb_int len = ARY_LEN(a)-1;
+      mrb_value *ptr = ARY_PTR(a);
+
+      ARY_SET_LEN(a, len);
+      memmove(&ptr[i], &ptr[i + 1], (len - i) * sizeof(mrb_value));
       break;
     }
   }
@@ -678,8 +681,8 @@ gc_mark_children(mrb_state *mrb, mrb_gc *gc, struct RBasic *obj)
       struct RArray *a = (struct RArray*)obj;
       size_t i, e;
 
-      for (i=0,e=a->len; i<e; i++) {
-        mrb_gc_mark_value(mrb, a->ptr[i]);
+      for (i=0,e=ARY_LEN(a); i<e; i++) {
+        mrb_gc_mark_value(mrb, ARY_PTR(a)[i]);
       }
     }
     break;
@@ -790,9 +793,9 @@ obj_free(mrb_state *mrb, struct RBasic *obj, int end)
 
   case MRB_TT_ARRAY:
     if (ARY_SHARED_P(obj))
-      mrb_ary_decref(mrb, ((struct RArray*)obj)->aux.shared);
-    else
-      mrb_free(mrb, ((struct RArray*)obj)->ptr);
+      mrb_ary_decref(mrb, ((struct RArray*)obj)->as.heap.aux.shared);
+    else if (!ARY_EMBED_P(obj))
+      mrb_free(mrb, ((struct RArray*)obj)->as.heap.ptr);
     break;
 
   case MRB_TT_HASH:
@@ -950,7 +953,7 @@ gc_gray_mark(mrb_state *mrb, mrb_gc *gc, struct RBasic *obj)
   case MRB_TT_ARRAY:
     {
       struct RArray *a = (struct RArray*)obj;
-      children += a->len;
+      children += ARY_LEN(a);
     }
     break;