1 /*
2 * Copyright (c) 2019, 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 /*
25 * @test
26 * @run testng TestMemoryAlignment
27 */
28
29 import jdk.incubator.foreign.MemoryLayouts;
30 import jdk.incubator.foreign.MemoryLayout;
31
32 import jdk.incubator.foreign.GroupLayout;
33 import jdk.incubator.foreign.MemoryLayout.PathElement;
34 import jdk.incubator.foreign.MemoryAddress;
35 import jdk.incubator.foreign.MemorySegment;
36 import jdk.incubator.foreign.SequenceLayout;
37 import jdk.incubator.foreign.ValueLayout;
38 import java.lang.invoke.VarHandle;
39 import java.util.stream.LongStream;
40
41 import org.testng.annotations.*;
42 import static org.testng.Assert.*;
43
44 public class TestMemoryAlignment {
45
46 @Test(dataProvider = "alignments")
47 public void testAlignedAccess(long align) {
48 ValueLayout layout = MemoryLayouts.BITS_32_BE;
49 assertEquals(layout.bitAlignment(), 32);
50 ValueLayout aligned = layout.withBitAlignment(align);
51 assertEquals(aligned.bitAlignment(), align); //unreasonable alignment here, to make sure access throws
52 VarHandle vh = aligned.varHandle(int.class);
53 try (MemorySegment segment = MemorySegment.allocateNative(aligned)) {
54 MemoryAddress addr = segment.baseAddress();
55 vh.set(addr, -42);
56 int val = (int)vh.get(addr);
57 assertEquals(val, -42);
58 }
59 }
60
61 @Test(dataProvider = "alignments")
62 public void testUnalignedAccess(long align) {
63 ValueLayout layout = MemoryLayouts.BITS_32_BE;
64 assertEquals(layout.bitAlignment(), 32);
65 ValueLayout aligned = layout.withBitAlignment(align);
66 MemoryLayout alignedGroup = MemoryLayout.ofStruct(MemoryLayouts.PAD_8, aligned);
67 assertEquals(alignedGroup.bitAlignment(), align);
68 VarHandle vh = aligned.varHandle(int.class);
69 try (MemorySegment segment = MemorySegment.allocateNative(alignedGroup)) {
70 MemoryAddress addr = segment.baseAddress();
71 vh.set(addr.offset(1L), -42);
72 assertEquals(align, 8); //this is the only case where access is aligned
73 } catch (IllegalStateException ex) {
74 assertNotEquals(align, 8); //if align != 8, access is always unaligned
75 }
76 }
77
78 @Test(dataProvider = "alignments")
79 public void testUnalignedPath(long align) {
80 MemoryLayout layout = MemoryLayouts.BITS_32_BE;
81 MemoryLayout aligned = layout.withBitAlignment(align).withName("value");
82 GroupLayout alignedGroup = MemoryLayout.ofStruct(MemoryLayouts.PAD_8, aligned);
83 try {
84 alignedGroup.varHandle(int.class, PathElement.groupElement("value"));
85 assertEquals(align, 8); //this is the only case where path is aligned
86 } catch (UnsupportedOperationException ex) {
87 assertNotEquals(align, 8); //if align != 8, path is always unaligned
88 }
89 }
90
91 @Test(dataProvider = "alignments")
92 public void testUnalignedSequence(long align) {
93 SequenceLayout layout = MemoryLayout.ofSequence(5, MemoryLayouts.BITS_32_BE.withBitAlignment(align));
94 VarHandle vh = layout.varHandle(int.class, PathElement.sequenceElement());
95 try (MemorySegment segment = MemorySegment.allocateNative(layout)) {
96 MemoryAddress addr = segment.baseAddress();
97 for (long i = 0 ; i < 5 ; i++) {
98 vh.set(addr, i, -42);
99 }
100 assertTrue(align <= 32); //if align <= 32, access is always aligned
101 } catch (IllegalStateException ex) {
102 assertTrue(align > 32); //if align > 32, access is always unaligned (for some elements)
103 }
104 }
105
106 @Test
107 public void testPackedAccess() {
108 ValueLayout vChar = MemoryLayouts.BITS_8_BE;
109 ValueLayout vShort = MemoryLayouts.BITS_16_BE;
110 ValueLayout vInt = MemoryLayouts.BITS_32_BE;
111 //mimic pragma pack(1)
112 GroupLayout g = MemoryLayout.ofStruct(vChar.withBitAlignment(8).withName("a"),
113 vShort.withBitAlignment(8).withName("b"),
114 vInt.withBitAlignment(8).withName("c"));
115 assertEquals(g.bitAlignment(), 8);
116 VarHandle vh_c = g.varHandle(byte.class, PathElement.groupElement("a"));
117 VarHandle vh_s = g.varHandle(short.class, PathElement.groupElement("b"));
118 VarHandle vh_i = g.varHandle(int.class, PathElement.groupElement("c"));
119 try (MemorySegment segment = MemorySegment.allocateNative(g)) {
120 MemoryAddress addr = segment.baseAddress();
121 vh_c.set(addr, Byte.MIN_VALUE);
122 assertEquals(vh_c.get(addr), Byte.MIN_VALUE);
123 vh_s.set(addr, Short.MIN_VALUE);
124 assertEquals(vh_s.get(addr), Short.MIN_VALUE);
125 vh_i.set(addr, Integer.MIN_VALUE);
126 assertEquals(vh_i.get(addr), Integer.MIN_VALUE);
127 }
128 }
129
130 @DataProvider(name = "alignments")
131 public Object[][] createAlignments() {
132 return LongStream.range(3, 32)
133 .mapToObj(v -> new Object[] { 1L << v })
134 .toArray(Object[][]::new);
135 }
136 }