ko1	2013-08-12 15:19:15 +0900 (Mon, 12 Aug 2013)

  New Revision: 42534

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=42534

  Log:
    * class.c (rb_prepend_module): make T_ICLASS object shady because
      this T_ICLASS object seems to share method table with other class
      objects. It was causes WB miss.
      TODO: need to know the data structure.
    * test/ruby/test_module.rb: add a test for WB miss.

  Modified files:
    trunk/ChangeLog
    trunk/class.c
    trunk/test/ruby/test_module.rb
Index: ChangeLog
===================================================================
--- ChangeLog	(revision 42533)
+++ ChangeLog	(revision 42534)
@@ -1,3 +1,12 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1
+Mon Aug 12 15:16:58 2013  Koichi Sasada  <ko1@a...>
+
+	* class.c (rb_prepend_module): make T_ICLASS object shady because
+	  this T_ICLASS object seems to share method table with other class
+	  objects. It was causes WB miss.
+	  TODO: need to know the data structure.
+
+	* test/ruby/test_module.rb: add a test for WB miss.
+
 Mon Aug 12 13:47:54 2013  Zachary Scott  <e@z...>
 
 	* process.c: [DOC] RDoc formatting of Process.clock_gettime
Index: class.c
===================================================================
--- class.c	(revision 42533)
+++ class.c	(revision 42534)
@@ -826,6 +826,7 @@ rb_prepend_module(VALUE klass, VALUE mod https://github.com/ruby/ruby/blob/trunk/class.c#L826
     origin = RCLASS_ORIGIN(klass);
     if (origin == klass) {
 	origin = class_alloc(T_ICLASS, klass);
+	OBJ_WB_UNPROTECT(origin); /* TODO: conservertive shading. Need more survery. */
 	RCLASS_SET_SUPER(origin, RCLASS_SUPER(klass));
 	RCLASS_SET_SUPER(klass, origin);
 	RCLASS_ORIGIN(klass) = origin;
Index: test/ruby/test_module.rb
===================================================================
--- test/ruby/test_module.rb	(revision 42533)
+++ test/ruby/test_module.rb	(revision 42534)
@@ -1760,4 +1760,20 @@ class TestModule < Test::Unit::TestCase https://github.com/ruby/ruby/blob/trunk/test/ruby/test_module.rb#L1760
       self.#{method}
     INPUT
   end
+
+  def test_prepend_gc
+    assert_separately [], %{
+      module Foo
+      end
+      class Object
+        prepend Foo
+      end
+      GC.start     # make created T_ICLASS old (or remembered shady)
+      class Object # add methods into T_ICLASS (need WB if it is old)
+        def foo; end
+        attr_reader :bar
+      end
+      1_000_000.times{''} # cause GC
+    }
+  end
 end

--
ML: ruby-changes@q...
Info: http://www.atdot.net/~ko1/quickml/