1 /*
2 * Copyright (c) 2017, 2018 Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 #include "precompiled.hpp"
25 #include "gc/shared/preservedMarks.inline.hpp"
26 #include "oops/oop.inline.hpp"
27 #include "unittest.hpp"
28
29 class ScopedDisabledBiasedLocking {
30 bool _orig;
31 public:
ScopedDisabledBiasedLocking()32 ScopedDisabledBiasedLocking() : _orig(UseBiasedLocking) { UseBiasedLocking = false; }
~ScopedDisabledBiasedLocking()33 ~ScopedDisabledBiasedLocking() { UseBiasedLocking = _orig; }
34 };
35
36 // Class to create a "fake" oop with a mark that will
37 // return true for calls to must_be_preserved().
38 class FakeOop {
39 oopDesc _oop;
40
41 public:
FakeOop()42 FakeOop() : _oop() { _oop.set_mark_raw(originalMark()); }
43
get_oop()44 oop get_oop() { return &_oop; }
mark()45 markOop mark() { return _oop.mark_raw(); }
set_mark(markOop m)46 void set_mark(markOop m) { _oop.set_mark_raw(m); }
forward_to(oop obj)47 void forward_to(oop obj) {
48 markOop m = markOopDesc::encode_pointer_as_mark(obj);
49 _oop.set_mark_raw(m);
50 }
51
originalMark()52 static markOop originalMark() { return markOop(markOopDesc::lock_mask_in_place); }
changedMark()53 static markOop changedMark() { return markOop(0x4711); }
54 };
55
TEST_VM(PreservedMarks,iterate_and_restore)56 TEST_VM(PreservedMarks, iterate_and_restore) {
57 // Need to disable biased locking to easily
58 // create oops that "must_be_preseved"
59 ScopedDisabledBiasedLocking dbl;
60
61 PreservedMarks pm;
62 FakeOop o1;
63 FakeOop o2;
64 FakeOop o3;
65 FakeOop o4;
66
67 // Make sure initial marks are correct.
68 ASSERT_EQ(o1.mark(), FakeOop::originalMark());
69 ASSERT_EQ(o2.mark(), FakeOop::originalMark());
70 ASSERT_EQ(o3.mark(), FakeOop::originalMark());
71 ASSERT_EQ(o4.mark(), FakeOop::originalMark());
72
73 // Change the marks and verify change.
74 o1.set_mark(FakeOop::changedMark());
75 o2.set_mark(FakeOop::changedMark());
76 ASSERT_EQ(o1.mark(), FakeOop::changedMark());
77 ASSERT_EQ(o2.mark(), FakeOop::changedMark());
78
79 // Push o1 and o2 to have their marks preserved.
80 pm.push(o1.get_oop(), o1.mark());
81 pm.push(o2.get_oop(), o2.mark());
82
83 // Fake a move from o1->o3 and o2->o4.
84 o1.forward_to(o3.get_oop());
85 o2.forward_to(o4.get_oop());
86 ASSERT_EQ(o1.get_oop()->forwardee(), o3.get_oop());
87 ASSERT_EQ(o2.get_oop()->forwardee(), o4.get_oop());
88 // Adjust will update the PreservedMarks stack to
89 // make sure the mark is updated at the new location.
90 pm.adjust_during_full_gc();
91
92 // Restore all preserved and verify that the changed
93 // mark is now present at o3 and o4.
94 pm.restore();
95 ASSERT_EQ(o3.mark(), FakeOop::changedMark());
96 ASSERT_EQ(o4.mark(), FakeOop::changedMark());
97 }
98