1 /*
2 * Copyright Amazon.com Inc. 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/slidingForwarding.inline.hpp"
26 #include "oops/markWord.hpp"
27 #include "oops/oop.inline.hpp"
28 #include "utilities/align.hpp"
29 #include "unittest.hpp"
30
31 #ifdef _LP64
32 #ifndef PRODUCT
33
34 static uintptr_t make_mark(uintptr_t target_region, uintptr_t offset) {
35 return (target_region) << 3 | (offset << 4) | 3 /* forwarded */;
36 }
37
38 static uintptr_t make_fallback() {
39 return ((uintptr_t(1) << 2) /* fallback */ | 3 /* forwarded */);
40 }
41
42 // Test simple forwarding within the same region.
43 TEST_VM(SlidingForwarding, simple) {
44 HeapWord fakeheap[32] = { nullptr };
45 HeapWord* heap = align_up(fakeheap, 8 * sizeof(HeapWord));
46 oop obj1 = cast_to_oop(&heap[2]);
47 oop obj2 = cast_to_oop(&heap[0]);
48 SlidingForwarding::initialize(MemRegion(&heap[0], &heap[16]), 8);
49 obj1->set_mark(markWord::prototype());
50 SlidingForwarding::begin();
51
52 SlidingForwarding::forward_to(obj1, obj2);
53 ASSERT_EQ(obj1->mark().value(), make_mark(0 /* target_region */, 0 /* offset */));
54 ASSERT_EQ(SlidingForwarding::forwardee(obj1), obj2);
55
56 SlidingForwarding::end();
57 }
58
59 // Test forwardings crossing 2 regions.
60 TEST_VM(SlidingForwarding, tworegions) {
61 HeapWord fakeheap[32] = { nullptr };
62 HeapWord* heap = align_up(fakeheap, 8 * sizeof(HeapWord));
63 oop obj1 = cast_to_oop(&heap[14]);
64 oop obj2 = cast_to_oop(&heap[2]);
65 oop obj3 = cast_to_oop(&heap[10]);
66 SlidingForwarding::initialize(MemRegion(&heap[0], &heap[16]), 8);
67 obj1->set_mark(markWord::prototype());
68 SlidingForwarding::begin();
69
70 SlidingForwarding::forward_to(obj1, obj2);
71 ASSERT_EQ(obj1->mark().value(), make_mark(0 /* target_region */, 2 /* offset */));
72 ASSERT_EQ(SlidingForwarding::forwardee(obj1), obj2);
73
74 SlidingForwarding::forward_to(obj1, obj3);
75 ASSERT_EQ(obj1->mark().value(), make_mark(1 /* target_region */, 2 /* offset */));
76 ASSERT_EQ(SlidingForwarding::forwardee(obj1), obj3);
77
78 SlidingForwarding::end();
79 }
80
81 // Test fallback forwardings crossing 4 regions.
82 TEST_VM(SlidingForwarding, fallback) {
83 HeapWord fakeheap[32] = { nullptr };
84 HeapWord* heap = align_up(fakeheap, 8 * sizeof(HeapWord));
85 oop s_obj1 = cast_to_oop(&heap[12]);
86 oop s_obj2 = cast_to_oop(&heap[13]);
87 oop s_obj3 = cast_to_oop(&heap[14]);
88 oop s_obj4 = cast_to_oop(&heap[15]);
89 oop t_obj1 = cast_to_oop(&heap[2]);
90 oop t_obj2 = cast_to_oop(&heap[4]);
91 oop t_obj3 = cast_to_oop(&heap[10]);
92 oop t_obj4 = cast_to_oop(&heap[12]);
93 SlidingForwarding::initialize(MemRegion(&heap[0], &heap[16]), 4);
94 s_obj1->set_mark(markWord::prototype());
95 s_obj2->set_mark(markWord::prototype());
96 s_obj3->set_mark(markWord::prototype());
97 s_obj4->set_mark(markWord::prototype());
98 SlidingForwarding::begin();
99
100 SlidingForwarding::forward_to(s_obj1, t_obj1);
101 ASSERT_EQ(s_obj1->mark().value(), make_mark(0 /* target_region */, 2 /* offset */));
102 ASSERT_EQ(SlidingForwarding::forwardee(s_obj1), t_obj1);
103
104 SlidingForwarding::forward_to(s_obj2, t_obj2);
105 ASSERT_EQ(s_obj2->mark().value(), make_mark(1 /* target_region */, 0 /* offset */));
106 ASSERT_EQ(SlidingForwarding::forwardee(s_obj2), t_obj2);
107
108 SlidingForwarding::forward_to(s_obj3, t_obj3);
109 ASSERT_EQ(s_obj3->mark().value(), make_fallback());
110 ASSERT_EQ(SlidingForwarding::forwardee(s_obj3), t_obj3);
111
112 SlidingForwarding::forward_to(s_obj4, t_obj4);
113 ASSERT_EQ(s_obj4->mark().value(), make_fallback());
114 ASSERT_EQ(SlidingForwarding::forwardee(s_obj4), t_obj4);
115
116 SlidingForwarding::end();
117 }
118
119 #endif // PRODUCT
120 #endif // _LP64