/*

 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

// Should this header be preserved during GC?

inline bool markOopDesc::must_be_preserved_with_bias(oop obj_containing_mark) const {

  assert(UseBiasedLocking, "unexpected");

  if (has_bias_pattern()) {

    // Will reset bias at end of collection

    // Mark words of biased and currently locked objects are preserved separately

    return false;

  }

  markOop prototype_header = prototype_for_object(obj_containing_mark);

  if (prototype_header->has_bias_pattern()) {

    // Individual instance which has its bias revoked; must return

    // true for correctness

    return true;

  }

  return (!is_unlocked() || !has_no_hash());

}

inline bool markOopDesc::must_be_preserved(oop obj_containing_mark) const {

  if (!UseBiasedLocking)

    return (!is_unlocked() || !has_no_hash());

  return must_be_preserved_with_bias(obj_containing_mark);

}

// Should this header (including its age bits) be preserved in the

// case of a promotion failure during scavenge?

inline bool markOopDesc::must_be_preserved_with_bias_for_promotion_failure(oop obj_containing_mark) const {

  assert(UseBiasedLocking, "unexpected");

  // We don't explicitly save off the mark words of biased and

  // currently-locked objects during scavenges, so if during a

  // promotion failure we encounter either a biased mark word or a

  // klass which still has a biasable prototype header, we have to

  // preserve the mark word. This results in oversaving, but promotion

  // failures are rare, and this avoids adding more complex logic to

  // the scavengers to call new variants of

  // BiasedLocking::preserve_marks() / restore_marks() in the middle

  // of a scavenge when a promotion failure has first been detected.

  if (has_bias_pattern() ||

      prototype_for_object(obj_containing_mark)->has_bias_pattern()) {

    return true;

  }

  return (this != prototype());

}

inline bool markOopDesc::must_be_preserved_for_promotion_failure(oop obj_containing_mark) const {

  if (!UseBiasedLocking)

    return (this != prototype());

  return must_be_preserved_with_bias_for_promotion_failure(obj_containing_mark);

}

// Should this header (including its age bits) be preserved in the

// case of a scavenge in which CMS is the old generation?

inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const {

  assert(UseBiasedLocking, "unexpected");

  // CMS scavenges preserve mark words in similar fashion to promotion failures; see above

  if (has_bias_pattern() ||

      klass_of_obj_containing_mark->klass_part()->prototype_header()->has_bias_pattern()) {

    return true;

  }

  return (this != prototype());

}

inline bool markOopDesc::must_be_preserved_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const {

  if (!UseBiasedLocking)

    return (this != prototype());

  return must_be_preserved_with_bias_for_cms_scavenge(klass_of_obj_containing_mark);

}

inline markOop markOopDesc::prototype_for_object(oop obj) {

#ifdef ASSERT

  markOop prototype_header = obj->klass()->klass_part()->prototype_header();

  assert(prototype_header == prototype() || prototype_header->has_bias_pattern(), "corrupt prototype header");

#endif

  return obj->klass()->klass_part()->prototype_header();

}