1 files changed, 247 insertions, 218 deletions

diff --git a/src/variable.c b/src/variable.c
index 72c13aa1f..d89295229 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -9,24 +9,19 @@
 #include <mruby/class.h>
 #include <mruby/proc.h>
 #include <mruby/string.h>
+#include <mruby/variable.h>
+#include <mruby/presym.h>
 
-typedef int (iv_foreach_func)(mrb_state*,mrb_sym,mrb_value,void*);
-
-#ifndef MRB_IV_SEGMENT_SIZE
-#define MRB_IV_SEGMENT_SIZE 4
-#endif
-
-typedef struct segment {
-  mrb_sym key[MRB_IV_SEGMENT_SIZE];
-  mrb_value val[MRB_IV_SEGMENT_SIZE];
-  struct segment *next;
-} segment;
+struct iv_elem {
+  mrb_sym key;
+  mrb_value val;
+};
 
 /* Instance variable table structure */
 typedef struct iv_tbl {
-  segment *rootseg;
   size_t size;
-  size_t last_len;
+  size_t alloc;
+  struct iv_elem *table;
 } iv_tbl;
 
 /* Creates the instance variable table. */
@@ -37,67 +32,82 @@ iv_new(mrb_state *mrb)
 
   t = (iv_tbl*)mrb_malloc(mrb, sizeof(iv_tbl));
   t->size = 0;
-  t->rootseg =  NULL;
-  t->last_len = 0;
+  t->alloc = 0;
+  t->table = NULL;
 
   return t;
 }
 
+static void iv_put(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value val);
+
+static void
+iv_rehash(mrb_state *mrb, iv_tbl *t)
+{
+  size_t old_alloc = t->alloc;
+  size_t new_alloc = old_alloc+1;
+  struct iv_elem *old_table = t->table;
+
+  khash_power2(new_alloc);
+  if (old_alloc == new_alloc) return;
+
+  t->alloc = new_alloc;
+  t->size = 0;
+  t->table = (struct iv_elem*)mrb_calloc(mrb, sizeof(struct iv_elem), new_alloc);
+
+  for (size_t i = 0; i < old_alloc; i++) {
+    struct iv_elem *slot = &old_table[i];
+
+    /* key = 0 means empty; val = undef means deleted */
+    if (slot->key != 0 && !mrb_undef_p(slot->val)) {
+      iv_put(mrb, t, slot->key, slot->val);
+    }
+  }
+  mrb_free(mrb, old_table);
+}
+
+#define slot_empty_p(slot) ((slot)->key == 0 && !mrb_undef_p((slot)->val))
+
 /* Set the value for the symbol in the instance variable table. */
 static void
 iv_put(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value val)
 {
-  segment *seg;
-  segment *prev = NULL;
-  segment *matched_seg = NULL;
-  size_t matched_idx = 0;
-  size_t i;
+  size_t hash, pos, start;
+  struct iv_elem *dslot = NULL;
 
   if (t == NULL) return;
-  seg = t->rootseg;
-  while (seg) {
-    for (i=0; i<MRB_IV_SEGMENT_SIZE; i++) {
-      mrb_sym key = seg->key[i];
-      /* Found room in last segment after last_len */
-      if (!seg->next && i >= t->last_len) {
-        seg->key[i] = sym;
-        seg->val[i] = val;
-        t->last_len = i+1;
+  if (t->alloc == 0) {
+    iv_rehash(mrb, t);
+  }
+  hash = kh_int_hash_func(mrb, sym);
+  start = pos = hash & (t->alloc-1);
+  for (;;) {
+    struct iv_elem *slot = &t->table[pos];
+
+    if (slot->key == sym) {
+      slot->val = val;
+      return;
+    }
+    else if (slot_empty_p(slot)) {
+      t->size++;
+      slot->key = sym;
+      slot->val = val;
+      return;
+    }
+    else if (!dslot && mrb_undef_p(slot->val)) { /* deleted */
+      dslot = slot;
+    }
+    pos = (pos+1) & (t->alloc-1);
+    if (pos == start) {         /* not found */
+      if (dslot) {
         t->size++;
+        dslot->key = sym;
+        dslot->val = val;
         return;
       }
-      if (!matched_seg && key == 0) {
-        matched_seg = seg;
-        matched_idx = i;
-      }
-      else if (key == sym) {
-        seg->val[i] = val;
-        return;
-      }
+      /* no room */
+      iv_rehash(mrb, t);
+      start = pos = hash & (t->alloc-1);
     }
-    prev = seg;
-    seg = seg->next;
-  }
-
-  /* Not found */
-  t->size++;
-  if (matched_seg) {
-    matched_seg->key[matched_idx] = sym;
-    matched_seg->val[matched_idx] = val;
-    return;
-  }
-
-  seg = (segment*)mrb_malloc(mrb, sizeof(segment));
-  if (!seg) return;
-  seg->next = NULL;
-  seg->key[0] = sym;
-  seg->val[0] = val;
-  t->last_len = 1;
-  if (prev) {
-    prev->next = seg;
-  }
-  else {
-    t->rootseg = seg;
   }
 }
 
@@ -105,133 +115,111 @@ iv_put(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value val)
 static mrb_bool
 iv_get(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value *vp)
 {
-  segment *seg;
-  size_t i;
+  size_t hash, pos, start;
 
   if (t == NULL) return FALSE;
-  seg = t->rootseg;
-  while (seg) {
-    for (i=0; i<MRB_IV_SEGMENT_SIZE; i++) {
-      mrb_sym key = seg->key[i];
+  if (t->alloc == 0) return FALSE;
+  if (t->size == 0) return FALSE;
 
-      if (!seg->next && i >= t->last_len) {
-        return FALSE;
-      }
-      if (key == sym) {
-        if (vp) *vp = seg->val[i];
-        return TRUE;
-      }
+  hash = kh_int_hash_func(mrb, sym);
+  start = pos = hash & (t->alloc-1);
+  for (;;) {
+    struct iv_elem *slot = &t->table[pos];
+
+    if (slot->key == sym) {
+      if (vp) *vp = slot->val;
+      return TRUE;
+    }
+    else if (slot_empty_p(slot)) {
+      return FALSE;
+    }
+    pos = (pos+1) & (t->alloc-1);
+    if (pos == start) {         /* not found */
+      return FALSE;
     }
-    seg = seg->next;
   }
-  return FALSE;
 }
 
 /* Deletes the value for the symbol from the instance variable table. */
 static mrb_bool
 iv_del(mrb_state *mrb, iv_tbl *t, mrb_sym sym, mrb_value *vp)
 {
-  segment *seg;
-  size_t i;
+  size_t hash, pos, start;
 
   if (t == NULL) return FALSE;
-  seg = t->rootseg;
-  while (seg) {
-    for (i=0; i<MRB_IV_SEGMENT_SIZE; i++) {
-      mrb_sym key = seg->key[i];
+  if (t->alloc == 0) return  FALSE;
+  if (t->size == 0) return FALSE;
 
-      if (!seg->next && i >= t->last_len) {
-        return FALSE;
-      }
-      if (key == sym) {
-        t->size--;
-        seg->key[i] = 0;
-        if (vp) *vp = seg->val[i];
-        return TRUE;
-      }
+  hash = kh_int_hash_func(mrb, sym);
+  start = pos = hash & (t->alloc-1);
+  for (;;) {
+    struct iv_elem *slot = &t->table[pos];
+
+    if (slot->key == sym) {
+      if (vp) *vp = slot->val;
+      t->size--;
+      slot->key = 0;
+      slot->val = mrb_undef_value();
+      return TRUE;
+    }
+    else if (slot_empty_p(slot)) {
+      return FALSE;
+    }
+    pos = (pos+1) & (t->alloc-1);
+    if (pos == start) {         /* not found */
+      return FALSE;
     }
-    seg = seg->next;
   }
-  return FALSE;
 }
 
 /* Iterates over the instance variable table. */
-static mrb_bool
-iv_foreach(mrb_state *mrb, iv_tbl *t, iv_foreach_func *func, void *p)
+static void
+iv_foreach(mrb_state *mrb, iv_tbl *t, mrb_iv_foreach_func *func, void *p)
 {
-  segment *seg;
   size_t i;
-  int n;
 
-  if (t == NULL) return TRUE;
-  seg = t->rootseg;
-  while (seg) {
-    for (i=0; i<MRB_IV_SEGMENT_SIZE; i++) {
-      mrb_sym key = seg->key[i];
+  if (t == NULL) return;
+  if (t->alloc == 0) return;
+  if (t->size == 0) return;
 
-      /* no value in last segment after last_len */
-      if (!seg->next && i >= t->last_len) {
-        return FALSE;
-      }
-      if (key != 0) {
-        n =(*func)(mrb, key, seg->val[i], p);
-        if (n > 0) return FALSE;
-        if (n < 0) {
-          t->size--;
-          seg->key[i] = 0;
-        }
+  for (i=0; i<t->alloc; i++) {
+    struct iv_elem *slot = &t->table[i];
+
+    if (slot->key && !mrb_undef_p(slot->val)) {
+      if ((*func)(mrb, slot->key, slot->val, p) != 0) {
+        return;
       }
     }
-    seg = seg->next;
   }
-  return TRUE;
+  return;
 }
 
 /* Get the size of the instance variable table. */
 static size_t
 iv_size(mrb_state *mrb, iv_tbl *t)
 {
-  segment *seg;
-  size_t size = 0;
-
   if (t == NULL) return 0;
-  if (t->size > 0) return t->size;
-  seg = t->rootseg;
-  while (seg) {
-    if (seg->next == NULL) {
-      size += t->last_len;
-      return size;
-    }
-    seg = seg->next;
-    size += MRB_IV_SEGMENT_SIZE;
-  }
-  /* empty iv_tbl */
-  return 0;
+  return t->size;
 }
 
 /* Copy the instance variable table. */
 static iv_tbl*
 iv_copy(mrb_state *mrb, iv_tbl *t)
 {
-  segment *seg;
   iv_tbl *t2;
-
   size_t i;
 
-  seg = t->rootseg;
-  t2 = iv_new(mrb);
+  if (t == NULL) return NULL;
+  if (t->alloc == 0) return NULL;
+  if (t->size == 0) return NULL;
 
-  while (seg != NULL) {
-    for (i=0; i<MRB_IV_SEGMENT_SIZE; i++) {
-      mrb_sym key = seg->key[i];
-      mrb_value val = seg->val[i];
+  t2 = iv_new(mrb);
+  for (i=0; i<t->alloc; i++) {
+    struct iv_elem *slot = &t->table[i];
 
-      if ((seg->next == NULL) && (i >= t->last_len)) {
-        return t2;
-      }
-      iv_put(mrb, t2, key, val);
+    if (slot->key && !mrb_undef_p(slot->val)) {
+      iv_put(mrb, t2, slot->key, slot->val);
     }
-    seg = seg->next;
   }
   return t2;
 }
@@ -240,14 +228,7 @@ iv_copy(mrb_state *mrb, iv_tbl *t)
 static void
 iv_free(mrb_state *mrb, iv_tbl *t)
 {
-  segment *seg;
-
-  seg = t->rootseg;
-  while (seg) {
-    segment *p = seg;
-    seg = seg->next;
-    mrb_free(mrb, p);
-  }
+  mrb_free(mrb, t->table);
   mrb_free(mrb, t);
 }
 
@@ -346,21 +327,30 @@ mrb_iv_get(mrb_state *mrb, mrb_value obj, mrb_sym sym)
 
 static inline void assign_class_name(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v);
 
-MRB_API void
-mrb_obj_iv_set(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
+void
+mrb_obj_iv_set_force(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
 {
-  iv_tbl *t;
-
-  if (MRB_FROZEN_P(obj)) {
-    mrb_raisef(mrb, E_FROZEN_ERROR, "can't modify frozen %S", mrb_obj_value(obj));
-  }
   assign_class_name(mrb, obj, sym, v);
   if (!obj->iv) {
     obj->iv = iv_new(mrb);
   }
-  t = obj->iv;
-  iv_put(mrb, t, sym, v);
-  mrb_write_barrier(mrb, (struct RBasic*)obj);
+  iv_put(mrb, obj->iv, sym, v);
+  mrb_field_write_barrier_value(mrb, (struct RBasic*)obj, v);
+}
+
+MRB_API void
+mrb_obj_iv_set(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
+{
+  mrb_check_frozen(mrb, obj);
+  mrb_obj_iv_set_force(mrb, obj, sym, v);
+}
+
+/* Iterates over the instance variable table. */
+MRB_API void
+mrb_iv_foreach(mrb_state *mrb, mrb_value obj, mrb_iv_foreach_func *func, void *p)
+{
+  if (!obj_iv_p(obj)) return;
+  iv_foreach(mrb, mrb_obj_ptr(obj)->iv, func, p);
 }
 
 static inline mrb_bool
@@ -374,20 +364,20 @@ assign_class_name(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
 {
   if (namespace_p(obj->tt) && namespace_p(mrb_type(v))) {
     struct RObject *c = mrb_obj_ptr(v);
-    if (obj != c && ISUPPER(mrb_sym2name(mrb, sym)[0])) {
-      mrb_sym id_classname = mrb_intern_lit(mrb, "__classname__");
+    if (obj != c && ISUPPER(mrb_sym_name_len(mrb, sym, NULL)[0])) {
+      mrb_sym id_classname = MRB_SYM(__classname__);
       mrb_value o = mrb_obj_iv_get(mrb, c, id_classname);
 
       if (mrb_nil_p(o)) {
-        mrb_sym id_outer = mrb_intern_lit(mrb, "__outer__");
+        mrb_sym id_outer = MRB_SYM(__outer__);
         o = mrb_obj_iv_get(mrb, c, id_outer);
 
         if (mrb_nil_p(o)) {
           if ((struct RClass *)obj == mrb->object_class) {
-            mrb_obj_iv_set(mrb, c, id_classname, mrb_symbol_value(sym));
+            mrb_obj_iv_set_force(mrb, c, id_classname, mrb_symbol_value(sym));
           }
           else {
-            mrb_obj_iv_set(mrb, c, id_outer, mrb_obj_value(obj));
+            mrb_obj_iv_set_force(mrb, c, id_outer, mrb_obj_value(obj));
           }
         }
       }
@@ -425,29 +415,24 @@ mrb_iv_defined(mrb_state *mrb, mrb_value obj, mrb_sym sym)
   return mrb_obj_iv_defined(mrb, mrb_obj_ptr(obj), sym);
 }
 
-#define identchar(c) (ISALNUM(c) || (c) == '_' || !ISASCII(c))
-
 MRB_API mrb_bool
 mrb_iv_name_sym_p(mrb_state *mrb, mrb_sym iv_name)
 {
   const char *s;
-  mrb_int i, len;
+  mrb_int len;
 
-  s = mrb_sym2name_len(mrb, iv_name, &len);
+  s = mrb_sym_name_len(mrb, iv_name, &len);
   if (len < 2) return FALSE;
   if (s[0] != '@') return FALSE;
-  if (s[1] == '@') return FALSE;
-  for (i=1; i<len; i++) {
-    if (!identchar(s[i])) return FALSE;
-  }
-  return TRUE;
+  if (ISDIGIT(s[1])) return FALSE;
+  return mrb_ident_p(s+1, len-1);
 }
 
 MRB_API void
 mrb_iv_name_sym_check(mrb_state *mrb, mrb_sym iv_name)
 {
   if (!mrb_iv_name_sym_p(mrb, iv_name)) {
-    mrb_name_error(mrb, iv_name, "'%S' is not allowed as an instance variable name", mrb_sym2str(mrb, iv_name));
+    mrb_name_error(mrb, iv_name, "'%n' is not allowed as an instance variable name", iv_name);
   }
 }
 
@@ -484,10 +469,10 @@ inspect_i(mrb_state *mrb, mrb_sym sym, mrb_value v, void *p)
   else {
     mrb_str_cat_lit(mrb, str, ", ");
   }
-  s = mrb_sym2name_len(mrb, sym, &len);
+  s = mrb_sym_name_len(mrb, sym, &len);
   mrb_str_cat(mrb, str, s, len);
   mrb_str_cat_lit(mrb, str, "=");
-  if (mrb_type(v) == MRB_TT_OBJECT) {
+  if (mrb_object_p(v)) {
     ins = mrb_any_to_s(mrb, v);
   }
   else {
@@ -510,7 +495,7 @@ mrb_obj_iv_inspect(mrb_state *mrb, struct RObject *obj)
     mrb_str_cat_lit(mrb, str, "-<");
     mrb_str_cat_cstr(mrb, str, cn);
     mrb_str_cat_lit(mrb, str, ":");
-    mrb_str_concat(mrb, str, mrb_ptr_to_str(mrb, obj));
+    mrb_str_cat_str(mrb, str, mrb_ptr_to_str(mrb, obj));
 
     iv_foreach(mrb, t, inspect_i, &str);
     mrb_str_cat_lit(mrb, str, ">");
@@ -526,6 +511,7 @@ mrb_iv_remove(mrb_state *mrb, mrb_value obj, mrb_sym sym)
     iv_tbl *t = mrb_obj_ptr(obj)->iv;
     mrb_value val;
 
+    mrb_check_frozen(mrb, mrb_obj_ptr(obj));
     if (iv_del(mrb, t, sym, &val)) {
       return val;
     }
@@ -541,7 +527,7 @@ iv_i(mrb_state *mrb, mrb_sym sym, mrb_value v, void *p)
   mrb_int len;
 
   ary = *(mrb_value*)p;
-  s = mrb_sym2name_len(mrb, sym, &len);
+  s = mrb_sym_name_len(mrb, sym, &len);
   if (len > 1 && s[0] == '@' && s[1] != '@') {
     mrb_ary_push(mrb, ary, mrb_symbol_value(sym));
   }
@@ -585,7 +571,7 @@ cv_i(mrb_state *mrb, mrb_sym sym, mrb_value v, void *p)
   mrb_int len;
 
   ary = *(mrb_value*)p;
-  s = mrb_sym2name_len(mrb, sym, &len);
+  s = mrb_sym_name_len(mrb, sym, &len);
   if (len > 2 && s[0] == '@' && s[1] == '@') {
     mrb_ary_push(mrb, ary, mrb_symbol_value(sym));
   }
@@ -595,7 +581,7 @@ cv_i(mrb_state *mrb, mrb_sym sym, mrb_value v, void *p)
 /* 15.2.2.4.19 */
 /*
  *  call-seq:
- *     mod.class_variables   -> array
+ *     mod.class_variables(inherit=true)   -> array
  *
  *  Returns an array of the names of class variables in <i>mod</i>.
  *
@@ -613,17 +599,20 @@ mrb_mod_class_variables(mrb_state *mrb, mrb_value mod)
 {
   mrb_value ary;
   struct RClass *c;
+  mrb_bool inherit = TRUE;
 
+  mrb_get_args(mrb, "|b", &inherit);
   ary = mrb_ary_new(mrb);
   c = mrb_class_ptr(mod);
   while (c) {
     iv_foreach(mrb, c->iv, cv_i, &ary);
+    if (!inherit) break;
     c = c->super;
   }
   return ary;
 }
 
-MRB_API mrb_value
+mrb_value
 mrb_mod_cv_get(mrb_state *mrb, struct RClass *c, mrb_sym sym)
 {
   struct RClass * cls = c;
@@ -640,8 +629,7 @@ mrb_mod_cv_get(mrb_state *mrb, struct RClass *c, mrb_sym sym)
   if (cls && cls->tt == MRB_TT_SCLASS) {
     mrb_value klass;
 
-    klass = mrb_obj_iv_get(mrb, (struct RObject *)cls,
-                           mrb_intern_lit(mrb, "__attached__"));
+    klass = mrb_obj_iv_get(mrb, (struct RObject *)cls, MRB_SYM(__attached__));
     c = mrb_class_ptr(klass);
     if (c->tt == MRB_TT_CLASS || c->tt == MRB_TT_MODULE) {
       given = FALSE;
@@ -654,8 +642,7 @@ mrb_mod_cv_get(mrb_state *mrb, struct RClass *c, mrb_sym sym)
       if (given) return v;
     }
   }
-  mrb_name_error(mrb, sym, "uninitialized class variable %S in %S",
-                 mrb_sym2str(mrb, sym), mrb_obj_value(cls));
+  mrb_name_error(mrb, sym, "uninitialized class variable %n in %C", sym, cls);
   /* not reached */
   return mrb_nil_value();
 }
@@ -675,8 +662,9 @@ mrb_mod_cv_set(mrb_state *mrb, struct RClass *c, mrb_sym sym, mrb_value v)
     iv_tbl *t = c->iv;
 
     if (iv_get(mrb, t, sym, NULL)) {
+      mrb_check_frozen(mrb, c);
       iv_put(mrb, t, sym, v);
-      mrb_write_barrier(mrb, (struct RBasic*)c);
+      mrb_field_write_barrier_value(mrb, (struct RBasic*)c, v);
       return;
     }
     c = c->super;
@@ -685,8 +673,7 @@ mrb_mod_cv_set(mrb_state *mrb, struct RClass *c, mrb_sym sym, mrb_value v)
   if (cls && cls->tt == MRB_TT_SCLASS) {
     mrb_value klass;
 
-    klass = mrb_obj_iv_get(mrb, (struct RObject*)cls,
-                           mrb_intern_lit(mrb, "__attached__"));
+    klass = mrb_obj_iv_get(mrb, (struct RObject*)cls, MRB_SYM(__attached__));
     switch (mrb_type(klass)) {
     case MRB_TT_CLASS:
     case MRB_TT_MODULE:
@@ -702,12 +689,13 @@ mrb_mod_cv_set(mrb_state *mrb, struct RClass *c, mrb_sym sym, mrb_value v)
     c = cls;
   }
 
+  mrb_check_frozen(mrb, c);
   if (!c->iv) {
     c->iv = iv_new(mrb);
   }
 
   iv_put(mrb, c->iv, sym, v);
-  mrb_write_barrier(mrb, (struct RBasic*)c);
+  mrb_field_write_barrier_value(mrb, (struct RBasic*)c, v);
 }
 
 MRB_API void
@@ -716,7 +704,7 @@ mrb_cv_set(mrb_state *mrb, mrb_value mod, mrb_sym sym, mrb_value v)
   mrb_mod_cv_set(mrb, mrb_class_ptr(mod), sym, v);
 }
 
-MRB_API mrb_bool
+mrb_bool
 mrb_mod_cv_defined(mrb_state *mrb, struct RClass * c, mrb_sym sym)
 {
   while (c) {
@@ -739,7 +727,13 @@ mrb_vm_cv_get(mrb_state *mrb, mrb_sym sym)
 {
   struct RClass *c;
 
-  c = MRB_PROC_TARGET_CLASS(mrb->c->ci->proc);
+  const struct RProc *p = mrb->c->ci->proc;
+
+  for (;;) {
+    c = MRB_PROC_TARGET_CLASS(p);
+    if (c && c->tt != MRB_TT_SCLASS) break;
+    p = p->upper;
+  }
   return mrb_mod_cv_get(mrb, c, sym);
 }
 
@@ -747,8 +741,13 @@ void
 mrb_vm_cv_set(mrb_state *mrb, mrb_sym sym, mrb_value v)
 {
   struct RClass *c;
+  const struct RProc *p = mrb->c->ci->proc;
 
-  c = MRB_PROC_TARGET_CLASS(mrb->c->ci->proc);
+  for (;;) {
+    c = MRB_PROC_TARGET_CLASS(p);
+    if (c && c->tt != MRB_TT_SCLASS) break;
+    p = p->upper;
+  }
   mrb_mod_cv_set(mrb, c, sym, v);
 }
 
@@ -767,16 +766,17 @@ mod_const_check(mrb_state *mrb, mrb_value mod)
 }
 
 static mrb_value
-const_get(mrb_state *mrb, struct RClass *base, mrb_sym sym)
+const_get(mrb_state *mrb, struct RClass *base, mrb_sym sym, mrb_bool skip)
 {
   struct RClass *c = base;
   mrb_value v;
   mrb_bool retry = FALSE;
   mrb_value name;
 
+  if (skip) c = c->super;
 L_RETRY:
   while (c) {
-    if (c->iv) {
+    if (!MRB_FLAG_TEST(c, MRB_FL_CLASS_IS_PREPENDED) && c->iv) {
       if (iv_get(mrb, c->iv, sym, &v))
         return v;
     }
@@ -788,14 +788,14 @@ L_RETRY:
     goto L_RETRY;
   }
   name = mrb_symbol_value(sym);
-  return mrb_funcall_argv(mrb, mrb_obj_value(base), mrb_intern_lit(mrb, "const_missing"), 1, &name);
+  return mrb_funcall_argv(mrb, mrb_obj_value(base), MRB_SYM(const_missing), 1, &name);
 }
 
 MRB_API mrb_value
 mrb_const_get(mrb_state *mrb, mrb_value mod, mrb_sym sym)
 {
   mod_const_check(mrb, mod);
-  return const_get(mrb, mrb_class_ptr(mod), sym);
+  return const_get(mrb, mrb_class_ptr(mod), sym, FALSE);
 }
 
 mrb_value
@@ -804,9 +804,10 @@ mrb_vm_const_get(mrb_state *mrb, mrb_sym sym)
   struct RClass *c;
   struct RClass *c2;
   mrb_value v;
-  struct RProc *proc;
+  const struct RProc *proc = mrb->c->ci->proc;
 
-  c = MRB_PROC_TARGET_CLASS(mrb->c->ci->proc);
+  c = MRB_PROC_TARGET_CLASS(proc);
+  if (!c) c = mrb->object_class;
   if (iv_get(mrb, c->iv, sym, &v)) {
     return v;
   }
@@ -814,15 +815,14 @@ mrb_vm_const_get(mrb_state *mrb, mrb_sym sym)
   while (c2 && c2->tt == MRB_TT_SCLASS) {
     mrb_value klass;
 
-    if (!iv_get(mrb, c2->iv, mrb_intern_lit(mrb, "__attached__"), &klass)) {
+    if (!iv_get(mrb, c2->iv, MRB_SYM(__attached__), &klass)) {
       c2 = NULL;
       break;
     }
     c2 = mrb_class_ptr(klass);
   }
   if (c2 && (c2->tt == MRB_TT_CLASS || c2->tt == MRB_TT_MODULE)) c = c2;
-  mrb_assert(!MRB_PROC_CFUNC_P(mrb->c->ci->proc));
-  proc = mrb->c->ci->proc;
+  proc = proc->upper;
   while (proc) {
     c2 = MRB_PROC_TARGET_CLASS(proc);
     if (c2 && iv_get(mrb, c2->iv, sym, &v)) {
@@ -830,7 +830,7 @@ mrb_vm_const_get(mrb_state *mrb, mrb_sym sym)
     }
     proc = proc->upper;
   }
-  return const_get(mrb, c, sym);
+  return const_get(mrb, c, sym, TRUE);
 }
 
 MRB_API void
@@ -849,6 +849,7 @@ mrb_vm_const_set(mrb_state *mrb, mrb_sym sym, mrb_value v)
   struct RClass *c;
 
   c = MRB_PROC_TARGET_CLASS(mrb->c->ci->proc);
+  if (!c) c = mrb->object_class;
   mrb_obj_iv_set(mrb, (struct RObject*)c, sym, v);
 }
 
@@ -860,6 +861,12 @@ mrb_const_remove(mrb_state *mrb, mrb_value mod, mrb_sym sym)
 }
 
 MRB_API void
+mrb_define_const_id(mrb_state *mrb, struct RClass *mod, mrb_sym name, mrb_value v)
+{
+  mrb_obj_iv_set(mrb, (struct RObject*)mod, name, v);
+}
+
+MRB_API void
 mrb_define_const(mrb_state *mrb, struct RClass *mod, const char *name, mrb_value v)
 {
   mrb_obj_iv_set(mrb, (struct RObject*)mod, mrb_intern_cstr(mrb, name), v);
@@ -879,9 +886,17 @@ const_i(mrb_state *mrb, mrb_sym sym, mrb_value v, void *p)
   mrb_int len;
 
   ary = *(mrb_value*)p;
-  s = mrb_sym2name_len(mrb, sym, &len);
+  s = mrb_sym_name_len(mrb, sym, &len);
   if (len >= 1 && ISUPPER(s[0])) {
-    mrb_ary_push(mrb, ary, mrb_symbol_value(sym));
+    mrb_int i, alen = RARRAY_LEN(ary);
+
+    for (i=0; i<alen; i++) {
+      if (mrb_symbol(RARRAY_PTR(ary)[i]) == sym)
+        break;
+    }
+    if (i==alen) {
+      mrb_ary_push(mrb, ary, mrb_symbol_value(sym));
+    }
   }
   return 0;
 }
@@ -891,7 +906,7 @@ const_i(mrb_state *mrb, mrb_sym sym, mrb_value v, void *p)
  *  call-seq:
  *     mod.constants    -> array
  *
- *  Returns an array of all names of contants defined in the receiver.
+ *  Returns an array of all names of constants defined in the receiver.
  */
 mrb_value
 mrb_mod_constants(mrb_state *mrb, mrb_value mod)
@@ -964,16 +979,8 @@ mrb_f_global_variables(mrb_state *mrb, mrb_value self)
 {
   iv_tbl *t = mrb->globals;
   mrb_value ary = mrb_ary_new(mrb);
-  size_t i;
-  char buf[3];
 
   iv_foreach(mrb, t, gv_i, &ary);
-  buf[0] = '$';
-  buf[2] = 0;
-  for (i = 1; i <= 9; ++i) {
-    buf[1] = (char)(i + '0');
-    mrb_ary_push(mrb, ary, mrb_symbol_value(mrb_intern(mrb, buf, 2)));
-  }
   return ary;
 }
 
@@ -1055,7 +1062,7 @@ outer_class(mrb_state *mrb, struct RClass *c)
 {
   mrb_value ov;
 
-  ov = mrb_obj_iv_get(mrb, (struct RObject*)c, mrb_intern_lit(mrb, "__outer__"));
+  ov = mrb_obj_iv_get(mrb, (struct RObject*)c, MRB_SYM(__outer__));
   if (mrb_nil_p(ov)) return NULL;
   switch (mrb_type(ov)) {
   case MRB_TT_CLASS:
@@ -1102,12 +1109,34 @@ mrb_class_find_path(mrb_state *mrb, struct RClass *c)
   mrb_str_cat_cstr(mrb, path, str);
   mrb_str_cat_cstr(mrb, path, "::");
 
-  str = mrb_sym2name_len(mrb, name, &len);
+  str = mrb_sym_name_len(mrb, name, &len);
   mrb_str_cat(mrb, path, str, len);
   if (RSTRING_PTR(path)[0] != '#') {
-    iv_del(mrb, c->iv, mrb_intern_lit(mrb, "__outer__"), NULL);
-    iv_put(mrb, c->iv, mrb_intern_lit(mrb, "__classname__"), path);
+    iv_del(mrb, c->iv, MRB_SYM(__outer__), NULL);
+    iv_put(mrb, c->iv, MRB_SYM(__classname__), path);
     mrb_field_write_barrier_value(mrb, (struct RBasic*)c, path);
+    path = mrb_str_dup(mrb, path);
   }
   return path;
 }
+
+size_t
+mrb_obj_iv_tbl_memsize(mrb_value obj)
+{
+  iv_tbl *t = mrb_obj_ptr(obj)->iv;
+  if (t == NULL) return 0;
+  return sizeof(iv_tbl) + t->alloc*sizeof(struct iv_elem);
+}
+
+#define identchar(c) (ISALNUM(c) || (c) == '_' || !ISASCII(c))
+
+mrb_bool
+mrb_ident_p(const char *s, mrb_int len)
+{
+  mrb_int i;
+
+  for (i = 0; i < len; i++) {
+    if (!identchar(s[i])) return FALSE;
+  }
+  return TRUE;
+}