* variable.c (rb_const_set): fix WB miss.

  WBs had located before creating reference between a klass
  and constant value. It causes GC bug.

    # pseudo code:
    WB(klass, value); # WB and remember klass
    st_insert(klass->const_table, const_id, value);

  `st_insert()' can cause GC before inserting `value' and
  forget `klass' from the remember set. After that, relationship
  between `klass' and `value' are created with constant table.
  Now, `value' can be young (shady) object and `klass' can be old
  object, without remembering `klass' object.
  At the next GC, old `klass' object will be skipped and
  young (shady) `value' will be miss-collected. -> GC bug

  Lesson: The place of a WB is important.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41396 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-06-19

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41397 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* hash.c: `st_update()' also has same issue of last fix.
  write barriers at callback function are too early.
  All write barriers are executed after `st_update()'



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41398 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm.c (kwmerge_i): add WB.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41399 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (gc_stress_set): add special option of GC.stress.
  `GC.stress=(flag)' accepts integer to control behavior of GC.
  See code for details. Of course, this feature is only for MRI.
  You can debug RGenGC (WB) using `GC.stress = 1'.
  Using this option, do minor marking at all possible places.
  GC::STRESS_MINOR_MARK = 1 and GC::STRESS_LAZY_SWEEP = 2
  seem good to add.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41400 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (RGENGC_CHECK_MODE): add new check mode `3'.
  In this mode, show all references if there is
  a miss-corrected object.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41401 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (rgengc_remember): check T_NONE and T_ZOMBIE
  if RGENGC_CHECK_MODE > 0.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41402 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (rgengc_remember): fix output level.
* gc.c (rgengc_rememberset_mark): fix to output clear count.
  (shady_object_count + clear_count = count of remembered objects)



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41403 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* bignum.c (rb_big_aref): Apply BIGLO to ~xds[i] for environment which
  BDIGIT is 16bit.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41404 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (make_deferred): clear flags to T_ZOMBIE.
* gc.c (slot_sweep_body): fix indent.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41405 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (rb_objspace::gc_stress): int -> VALUE to store Fixnum object.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41406 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* gc.c (garbage_collect_body): use FIX2INT for ruby_gc_stress.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41407 b2dd03c8-39d4-4d8f-98ff-823fe69b080e