iseq.c: mark parents of wrapped iseq

* iseq.c (iseqw_mark): as wrapped iseq is isolated from the call
  stack, it needs to take care of its parent and ancestors, so
  that they do not become orphans.  [ruby-core:72620] [Bug #11928]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53514 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Wed Jan 13 00:16:47 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* iseq.c (iseqw_mark): as wrapped iseq is isolated from the call
+	  stack, it needs to take care of its parent and ancestors, so
+	  that they do not become orphans.  [ruby-core:72620] [Bug #11928]
+
 Tue Jan 12 21:01:09 2016  Benoit Daloze  <eregontp@gmail.com>
 
 	* common.mk: update URL and name for the Ruby spec suite.

iseq.c

@@ -711,7 +711,11 @@ rb_iseq_coverage(const rb_iseq_t *iseq)
 static void
 iseqw_mark(void *ptr)
 {
+    const rb_iseq_t *iseq = ptr;
     rb_gc_mark((VALUE)ptr);
+    while ((iseq = iseq->body->parent_iseq) != NULL) {
+	rb_gc_mark((VALUE)iseq);
+    }
 }
 
 static size_t

test/ruby/bug-11928.rb

@@ -0,0 +1,14 @@
+class Segfault
+  at_exit { Segfault.new.segfault }
+
+  define_method 'segfault' do
+    n = 11928
+    v = nil
+    i = 0
+    while i < n
+      i += 1
+      v = (foo rescue $!).local_variables
+    end
+    assert_equal(%i[i n v], v.sort)
+  end
+end

test/ruby/test_exception.rb

@@ -701,6 +701,12 @@ end.join
     assert_equal(%i[a b c d e f g], e.local_variables.sort)
   end
 
+  def test_name_error_info_parent_iseq_mark
+    assert_separately(['-', File.join(__dir__, 'bug-11928.rb')], <<-'end;')
+      -> {require ARGV[0]}.call
+    end;
+  end
+
   def test_output_string_encoding
     # "\x82\xa0" in cp932 is "\u3042" (Japanese hiragana 'a')
     # change $stderr to force calling rb_io_write() instead of fwrite()