variable.c: remove generic ivar support for special constants

Special constants are all frozen since [Feature #8923] and cannot
support ivars.  Remove some unused code we had for supporting them.

* variable.c (special_generic_ivar): remove flag
  (givar_i, rb_mark_generic_ivar_tbl): remove functions
  (rb_free_generic_ivar, rb_ivar_lookup, rb_ivar_delete,
   generic_ivar_set, rb_ivar_set, rb_ivar_defined,
   rb_copy_generic_ivar, rb_ivar_foreach, rb_ivar_count,
   rb_obj_remove_instance_variable):
   adjust for lack of ivar support in special constants
* test/ruby/test_variable.rb: test ivars for special consts
* internal.h: remove rb_mark_generic_ivar_tbl decl
* gc.c (gc_mark_roots): remove rb_mark_generic_ivar_tbl call

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50758 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 47 insertions, 52 deletions

diff --git a/ChangeLog b/ChangeLog
index c3a5ff9ab3..f2811f5c0b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+Thu Jun  4 05:44:01 2015  Eric Wong  <e@80x24.org>
+
+	* variable.c (special_generic_ivar): remove flag
+	  (givar_i, rb_mark_generic_ivar_tbl): remove functions
+	  (rb_free_generic_ivar, rb_ivar_lookup, rb_ivar_delete,
+	   generic_ivar_set, rb_ivar_set, rb_ivar_defined,
+	   rb_copy_generic_ivar, rb_ivar_foreach, rb_ivar_count,
+	   rb_obj_remove_instance_variable):
+	   adjust for lack of ivar support in special constants
+	* test/ruby/test_variable.rb: test ivars for special consts
+	* internal.h: remove rb_mark_generic_ivar_tbl decl
+	* gc.c (gc_mark_roots): remove rb_mark_generic_ivar_tbl call
+
 Thu Jun  4 05:13:34 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_insnhelper.c (def_iseq_ptr): `iseqval' is not available any more.
diff --git a/gc.c b/gc.c
index d7269cf138..cf659ebfd9 100644
--- a/gc.c
+++ b/gc.c
@@ -4579,10 +4579,6 @@ gc_mark_roots(rb_objspace_t *objspace, const char **categoryp)
     MARK_CHECKPOINT("global_tbl");
     rb_gc_mark_global_tbl();
 
-    /* mark generic instance variables for special constants */
-    MARK_CHECKPOINT("generic_ivars");
-    rb_mark_generic_ivar_tbl();
-
     if (stress_to_class) rb_gc_mark(stress_to_class);
 
     MARK_CHECKPOINT("finish");
diff --git a/internal.h b/internal.h
index 06305f3b77..93208768d0 100644
--- a/internal.h
+++ b/internal.h
@@ -1284,7 +1284,6 @@ extern unsigned long ruby_scan_digits(const char *str, ssize_t len, int base, si
 /* variable.c (export) */
 void rb_gc_mark_global_tbl(void);
 void rb_mark_generic_ivar(VALUE);
-void rb_mark_generic_ivar_tbl(void);
 VALUE rb_const_missing(VALUE klass, VALUE name);
 
 int rb_st_insert_id_and_value(VALUE obj, st_table *tbl, ID key, VALUE value);
diff --git a/test/ruby/test_variable.rb b/test/ruby/test_variable.rb
index 8f5329bb1c..f04e358e62 100644
--- a/test/ruby/test_variable.rb
+++ b/test/ruby/test_variable.rb
@@ -118,4 +118,22 @@ class TestVariable < Test::Unit::TestCase
       }
     }
   end
+
+  def test_special_constant_ivars
+    [ true, false, :symbol, "dsym#{rand(9999)}".to_sym, 1, 1.0 ].each do |v|
+      assert_empty v.instance_variables
+      msg = "can't modify frozen #{v.class}"
+
+      assert_raise_with_message(RuntimeError, msg) do
+        v.instance_variable_set(:@foo, :bar)
+      end
+
+      assert_nil v.instance_variable_get(:@foo)
+      refute v.instance_variable_defined?(:@foo)
+
+      assert_raise_with_message(RuntimeError, msg) do
+        v.remove_instance_variable(:@foo)
+      end
+    end
+  end
 end
diff --git a/variable.c b/variable.c
index a5f6579b37..e130ee1149 100644
--- a/variable.c
+++ b/variable.c
@@ -25,7 +25,6 @@ static void setup_const_entry(rb_const_entry_t *, VALUE, VALUE, rb_const_flag_t)
 static int const_update(st_data_t *, st_data_t *, st_data_t, int);
 static st_table *generic_iv_tbl;
 static st_table *generic_iv_tbl_compat;
-static int special_generic_ivar;
 
 /* per-object */
 struct gen_ivtbl {
@@ -1182,23 +1181,6 @@ rb_mark_generic_ivar(VALUE obj)
     }
 }
 
-static int
-givar_i(st_data_t k, st_data_t v, st_data_t a)
-{
-    VALUE obj = (VALUE)k;
-    if (rb_special_const_p(obj)) {
-	gen_ivtbl_mark((const struct gen_ivtbl *)v);
-    }
-    return ST_CONTINUE;
-}
-
-void
-rb_mark_generic_ivar_tbl(void)
-{
-    if (special_generic_ivar == 0) return;
-    st_foreach_safe(generic_iv_tbl, givar_i, 0);
-}
-
 void
 rb_free_generic_ivar(VALUE obj)
 {
@@ -1249,7 +1231,7 @@ rb_ivar_lookup(VALUE obj, ID id, VALUE undef)
     long len;
     st_data_t index;
 
-    if (SPECIAL_CONST_P(obj)) goto generic;
+    if (SPECIAL_CONST_P(obj)) return undef;
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         len = ROBJECT_NUMIV(obj);
@@ -1268,8 +1250,7 @@ rb_ivar_lookup(VALUE obj, ID id, VALUE undef)
 	    return (VALUE)index;
 	break;
       default:
-      generic:
-	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj))
+	if (FL_TEST(obj, FL_EXIVAR))
 	    return generic_ivar_get(obj, id, undef);
 	break;
     }
@@ -1303,7 +1284,7 @@ rb_ivar_delete(VALUE obj, ID id, VALUE undef)
     long len;
     st_data_t index;
 
-    if (SPECIAL_CONST_P(obj)) goto generic;
+    rb_check_frozen(obj);
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         len = ROBJECT_NUMIV(obj);
@@ -1323,8 +1304,7 @@ rb_ivar_delete(VALUE obj, ID id, VALUE undef)
 	    return (VALUE)index;
 	break;
       default:
-      generic:
-	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj))
+	if (FL_TEST(obj, FL_EXIVAR))
 	    return generic_ivar_delete(obj, id, undef);
 	break;
     }
@@ -1369,11 +1349,6 @@ generic_ivar_set(VALUE obj, ID id, VALUE val)
 {
     struct ivar_update ivup;
 
-    if (rb_special_const_p(obj)) {
-	if (rb_obj_frozen_p(obj)) rb_error_frozen("object");
-	special_generic_ivar = 1;
-    }
-
     ivup.extended = 0;
     ivup.u.iv_index_tbl = iv_index_tbl_make(obj);
     iv_index_tbl_extend(&ivup, id);
@@ -1392,7 +1367,7 @@ rb_ivar_set(VALUE obj, ID id, VALUE val)
     long i, len;
 
     rb_check_frozen(obj);
-    if (SPECIAL_CONST_P(obj)) goto generic;
+
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         ivup.extended = 0;
@@ -1436,7 +1411,6 @@ rb_ivar_set(VALUE obj, ID id, VALUE val)
 	rb_st_insert_id_and_value(obj, RCLASS_IV_TBL(obj), (st_data_t)id, val);
         break;
       default:
-      generic:
 	generic_ivar_set(obj, id, val);
 	break;
     }
@@ -1449,7 +1423,8 @@ rb_ivar_defined(VALUE obj, ID id)
     VALUE val;
     struct st_table *iv_index_tbl;
     st_data_t index;
-    if (SPECIAL_CONST_P(obj)) goto generic;
+
+    if (SPECIAL_CONST_P(obj)) return Qfalse;
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);
@@ -1466,8 +1441,7 @@ rb_ivar_defined(VALUE obj, ID id)
 	    return Qtrue;
 	break;
       default:
-      generic:
-	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj))
+	if (FL_TEST(obj, FL_EXIVAR))
 	    return generic_ivar_defined(obj, id);
 	break;
     }
@@ -1577,10 +1551,7 @@ rb_copy_generic_ivar(VALUE clone, VALUE obj)
 {
     struct gen_ivtbl *ivtbl;
 
-    if (rb_special_const_p(clone)) {
-	if (rb_obj_frozen_p(clone)) rb_error_frozen("object");
-	special_generic_ivar = 1;
-    }
+    rb_check_frozen(clone);
 
     if (!FL_TEST(obj, FL_EXIVAR)) {
       clear:
@@ -1620,7 +1591,7 @@ rb_copy_generic_ivar(VALUE clone, VALUE obj)
 void
 rb_ivar_foreach(VALUE obj, int (*func)(ANYARGS), st_data_t arg)
 {
-    if (SPECIAL_CONST_P(obj)) goto generic;
+    if (SPECIAL_CONST_P(obj)) return;
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         obj_ivar_each(obj, func, arg);
@@ -1632,8 +1603,7 @@ rb_ivar_foreach(VALUE obj, int (*func)(ANYARGS), st_data_t arg)
 	}
 	break;
       default:
-      generic:
-	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
+	if (FL_TEST(obj, FL_EXIVAR)) {
 	    gen_ivar_each(obj, func, arg);
 	}
 	break;
@@ -1644,7 +1614,9 @@ st_index_t
 rb_ivar_count(VALUE obj)
 {
     st_table *tbl;
-    if (SPECIAL_CONST_P(obj)) goto generic;
+
+    if (SPECIAL_CONST_P(obj)) return 0;
+
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
 	if ((tbl = ROBJECT_IV_INDEX_TBL(obj)) != 0) {
@@ -1665,8 +1637,7 @@ rb_ivar_count(VALUE obj)
 	}
 	break;
       default:
-      generic:
-	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
+	if (FL_TEST(obj, FL_EXIVAR)) {
 	    struct gen_ivtbl *ivtbl;
 
 	    if (gen_ivtbl_get(obj, &ivtbl)) {
@@ -1764,7 +1735,6 @@ rb_obj_remove_instance_variable(VALUE obj, VALUE name)
 		      QUOTE_ID(id));
     }
 
-    if (SPECIAL_CONST_P(obj)) goto generic;
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         iv_index_tbl = ROBJECT_IV_INDEX_TBL(obj);
@@ -1785,8 +1755,7 @@ rb_obj_remove_instance_variable(VALUE obj, VALUE name)
 	}
 	break;
       default:
-      generic:
-	if (FL_TEST(obj, FL_EXIVAR) || rb_special_const_p(obj)) {
+	if (FL_TEST(obj, FL_EXIVAR)) {
 	    v = val;
 	    if (generic_ivar_remove(obj, (st_data_t)id, &v)) {
 		return (VALUE)v;