/*

 * Copyright (c) 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#include "precompiled.hpp"

#include "gc/shared/preservedMarks.inline.hpp"

#include "unittest.hpp"

class ScopedDisabledBiasedLocking {

  bool _orig;

public:

  ScopedDisabledBiasedLocking() : _orig(UseBiasedLocking) { UseBiasedLocking = false; }

  ~ScopedDisabledBiasedLocking() { UseBiasedLocking = _orig; }

};

// Class to create a "fake" oop with a mark that will

// return true for calls to must_be_preserved().

class FakeOop {

  oopDesc _oop;

public:

  FakeOop() : _oop() { _oop.set_mark(originalMark()); }

  oop get_oop() { return &_oop; }

  markOop mark() { return _oop.mark(); }

  void set_mark(markOop m) { _oop.set_mark(m); }

  void forward_to(oop obj) {

    markOop m = markOopDesc::encode_pointer_as_mark(obj);

    _oop.set_mark(m);

  }

  static markOop originalMark() { return markOop(markOopDesc::lock_mask_in_place); }

  static markOop changedMark()  { return markOop(0x4711); }

};

TEST_VM(PreservedMarks, iterate_and_restore) {

  // Need to disable biased locking to easily

  // create oops that "must_be_preseved"

  ScopedDisabledBiasedLocking dbl;

  PreservedMarks pm;

  FakeOop o1;

  FakeOop o2;

  FakeOop o3;

  FakeOop o4;

  // Make sure initial marks are correct.

  ASSERT_EQ(o1.mark(), FakeOop::originalMark());

  ASSERT_EQ(o2.mark(), FakeOop::originalMark());

  ASSERT_EQ(o3.mark(), FakeOop::originalMark());

  ASSERT_EQ(o4.mark(), FakeOop::originalMark());

  // Change the marks and verify change.

  o1.set_mark(FakeOop::changedMark());

  o2.set_mark(FakeOop::changedMark());

  ASSERT_EQ(o1.mark(), FakeOop::changedMark());

  ASSERT_EQ(o2.mark(), FakeOop::changedMark());

  // Push o1 and o2 to have their marks preserved.

  pm.push(o1.get_oop(), o1.mark());

  pm.push(o2.get_oop(), o2.mark());

  // Fake a move from o1->o3 and o2->o4.

  o1.forward_to(o3.get_oop());

  o2.forward_to(o4.get_oop());

  ASSERT_EQ(o1.get_oop()->forwardee(), o3.get_oop());

  ASSERT_EQ(o2.get_oop()->forwardee(), o4.get_oop());

  // Adjust will update the PreservedMarks stack to

  // make sure the mark is updated at the new location.

  pm.adjust_during_full_gc();

  // Restore all preserved and verify that the changed

  // mark is now present at o3 and o4.

  pm.restore();

  ASSERT_EQ(o3.mark(), FakeOop::changedMark());

  ASSERT_EQ(o4.mark(), FakeOop::changedMark());

}