Replace the implementation of method tables in classes/modules.

They are basically the copy of instance variable tables. On my Linux
box, memory consumption of `mrbtest` measured by `valgrind` is:

- old: 17,683,830 bytes
- new: 14,283,749 bytes

1 files changed, 1 insertions, 190 deletions

diff --git a/src/kernel.c b/src/kernel.c
index a23eeea4e..c34d0bb6e 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -218,191 +218,6 @@ mrb_obj_class_m(mrb_state *mrb, mrb_value self)
   return mrb_obj_value(mrb_obj_class(mrb, self));
 }
 
-static struct RClass*
-mrb_singleton_class_clone(mrb_state *mrb, mrb_value obj)
-{
-  struct RClass *klass = mrb_basic_ptr(obj)->c;
-
-  if (klass->tt != MRB_TT_SCLASS)
-    return klass;
-  else {
-    /* copy singleton(unnamed) class */
-    struct RClass *clone = (struct RClass*)mrb_obj_alloc(mrb, klass->tt, mrb->class_class);
-
-    switch (mrb_type(obj)) {
-    case MRB_TT_CLASS:
-    case MRB_TT_SCLASS:
-      break;
-    default:
-      clone->c = mrb_singleton_class_clone(mrb, mrb_obj_value(klass));
-      break;
-    }
-    clone->super = klass->super;
-    if (klass->iv) {
-      mrb_iv_copy(mrb, mrb_obj_value(clone), mrb_obj_value(klass));
-      mrb_obj_iv_set(mrb, (struct RObject*)clone, MRB_SYM(__attached__), obj);
-    }
-    if (klass->mt) {
-      clone->mt = kh_copy(mt, mrb, klass->mt);
-    }
-    else {
-      clone->mt = kh_init(mt, mrb);
-    }
-    clone->tt = MRB_TT_SCLASS;
-    return clone;
-  }
-}
-
-static void
-copy_class(mrb_state *mrb, mrb_value dst, mrb_value src)
-{
-  struct RClass *dc = mrb_class_ptr(dst);
-  struct RClass *sc = mrb_class_ptr(src);
-  /* if the origin is not the same as the class, then the origin and
-     the current class need to be copied */
-  if (sc->flags & MRB_FL_CLASS_IS_PREPENDED) {
-    struct RClass *c0 = sc->super;
-    struct RClass *c1 = dc;
-
-    /* copy prepended iclasses */
-    while (!(c0->flags & MRB_FL_CLASS_IS_ORIGIN)) {
-      c1->super = mrb_class_ptr(mrb_obj_dup(mrb, mrb_obj_value(c0)));
-      c1 = c1->super;
-      c0 = c0->super;
-    }
-    c1->super = mrb_class_ptr(mrb_obj_dup(mrb, mrb_obj_value(c0)));
-    c1->super->flags |= MRB_FL_CLASS_IS_ORIGIN;
-  }
-  if (sc->mt) {
-    dc->mt = kh_copy(mt, mrb, sc->mt);
-  }
-  else {
-    dc->mt = kh_init(mt, mrb);
-  }
-  dc->super = sc->super;
-  MRB_SET_INSTANCE_TT(dc, MRB_INSTANCE_TT(sc));
-}
-
-static mrb_value mrb_obj_init_copy(mrb_state *mrb, mrb_value self);
-
-static void
-init_copy(mrb_state *mrb, mrb_value dest, mrb_value obj)
-{
-  switch (mrb_type(obj)) {
-    case MRB_TT_ICLASS:
-      copy_class(mrb, dest, obj);
-      return;
-    case MRB_TT_CLASS:
-    case MRB_TT_MODULE:
-      copy_class(mrb, dest, obj);
-      mrb_iv_copy(mrb, dest, obj);
-      mrb_iv_remove(mrb, dest, MRB_SYM(__classname__));
-      break;
-    case MRB_TT_OBJECT:
-    case MRB_TT_SCLASS:
-    case MRB_TT_HASH:
-    case MRB_TT_DATA:
-    case MRB_TT_EXCEPTION:
-      mrb_iv_copy(mrb, dest, obj);
-      break;
-    case MRB_TT_ISTRUCT:
-      mrb_istruct_copy(dest, obj);
-      break;
-
-    default:
-      break;
-  }
-  if (!mrb_func_basic_p(mrb, dest, MRB_SYM(initialize_copy), mrb_obj_init_copy)) {
-    mrb_funcall_id(mrb, dest, MRB_SYM(initialize_copy), 1, obj);
-  }
-}
-
-/* 15.3.1.3.8  */
-/*
- *  call-seq:
- *     obj.clone -> an_object
- *
- *  Produces a shallow copy of <i>obj</i>---the instance variables of
- *  <i>obj</i> are copied, but not the objects they reference. Copies
- *  the frozen state of <i>obj</i>. See also the discussion
- *  under <code>Object#dup</code>.
- *
- *     class Klass
- *        attr_accessor :str
- *     end
- *     s1 = Klass.new      #=> #<Klass:0x401b3a38>
- *     s1.str = "Hello"    #=> "Hello"
- *     s2 = s1.clone       #=> #<Klass:0x401b3998 @str="Hello">
- *     s2.str[1,4] = "i"   #=> "i"
- *     s1.inspect          #=> "#<Klass:0x401b3a38 @str=\"Hi\">"
- *     s2.inspect          #=> "#<Klass:0x401b3998 @str=\"Hi\">"
- *
- *  This method may have class-specific behavior.  If so, that
- *  behavior will be documented under the #+initialize_copy+ method of
- *  the class.
- *
- *  Some Class(True False Nil Symbol Integer Float) Object  cannot clone.
- */
-MRB_API mrb_value
-mrb_obj_clone(mrb_state *mrb, mrb_value self)
-{
-  struct RObject *p;
-  mrb_value clone;
-
-  if (mrb_immediate_p(self)) {
-    return self;
-  }
-  if (mrb_sclass_p(self)) {
-    mrb_raise(mrb, E_TYPE_ERROR, "can't clone singleton class");
-  }
-  p = (struct RObject*)mrb_obj_alloc(mrb, mrb_type(self), mrb_obj_class(mrb, self));
-  p->c = mrb_singleton_class_clone(mrb, self);
-  mrb_field_write_barrier(mrb, (struct RBasic*)p, (struct RBasic*)p->c);
-  clone = mrb_obj_value(p);
-  init_copy(mrb, clone, self);
-  p->flags |= mrb_obj_ptr(self)->flags & MRB_FL_OBJ_IS_FROZEN;
-
-  return clone;
-}
-
-/* 15.3.1.3.9  */
-/*
- *  call-seq:
- *     obj.dup -> an_object
- *
- *  Produces a shallow copy of <i>obj</i>---the instance variables of
- *  <i>obj</i> are copied, but not the objects they reference.
- *  <code>dup</code> copies the frozen state of <i>obj</i>. See also
- *  the discussion under <code>Object#clone</code>. In general,
- *  <code>clone</code> and <code>dup</code> may have different semantics
- *  in descendant classes. While <code>clone</code> is used to duplicate
- *  an object, including its internal state, <code>dup</code> typically
- *  uses the class of the descendant object to create the new instance.
- *
- *  This method may have class-specific behavior.  If so, that
- *  behavior will be documented under the #+initialize_copy+ method of
- *  the class.
- */
-
-MRB_API mrb_value
-mrb_obj_dup(mrb_state *mrb, mrb_value obj)
-{
-  struct RBasic *p;
-  mrb_value dup;
-
-  if (mrb_immediate_p(obj)) {
-    return obj;
-  }
-  if (mrb_sclass_p(obj)) {
-    mrb_raise(mrb, E_TYPE_ERROR, "can't dup singleton class");
-  }
-  p = mrb_obj_alloc(mrb, mrb_type(obj), mrb_obj_class(mrb, obj));
-  dup = mrb_obj_value(p);
-  init_copy(mrb, dup, obj);
-
-  return dup;
-}
-
 static mrb_value
 mrb_obj_extend(mrb_state *mrb, mrb_int argc, mrb_value *argv, mrb_value obj)
 {
@@ -493,7 +308,7 @@ mrb_obj_hash(mrb_state *mrb, mrb_value self)
 }
 
 /* 15.3.1.3.16 */
-static mrb_value
+mrb_value
 mrb_obj_init_copy(mrb_state *mrb, mrb_value self)
 {
   mrb_value orig = mrb_get_arg1(mrb);
@@ -505,7 +320,6 @@ mrb_obj_init_copy(mrb_state *mrb, mrb_value self)
   return self;
 }
 
-
 MRB_API mrb_bool
 mrb_obj_is_instance_of(mrb_state *mrb, mrb_value obj, struct RClass* c)
 {
@@ -568,9 +382,6 @@ mrb_obj_is_kind_of_m(mrb_state *mrb, mrb_value self)
   return mrb_bool_value(mrb_obj_is_kind_of(mrb, self, c));
 }
 
-KHASH_DECLARE(st, mrb_sym, char, FALSE)
-KHASH_DEFINE(st, mrb_sym, char, FALSE, kh_int_hash_func, kh_int_hash_equal)
-
 /* 15.3.1.3.32 */
 /*
  * call_seq: