1 /* 2 * Copyright (c) 2019, 2020, 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") testAlignedAccess(long align)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") testUnalignedAccess(long align)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.addOffset(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") testUnalignedPath(long align)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") testUnalignedSequence(long align)92 public void testUnalignedSequence(long align) { 93 SequenceLayout layout = MemoryLayout.ofSequence(5, MemoryLayouts.BITS_32_BE.withBitAlignment(align)); 94 try { 95 VarHandle vh = layout.varHandle(int.class, PathElement.sequenceElement()); 96 try (MemorySegment segment = MemorySegment.allocateNative(layout)) { 97 MemoryAddress addr = segment.baseAddress(); 98 for (long i = 0 ; i < 5 ; i++) { 99 vh.set(addr, i, -42); 100 } 101 } 102 } catch (UnsupportedOperationException ex) { 103 assertTrue(align > 32); //if align > 32, access is always unaligned (for some elements) 104 } 105 } 106 107 @Test testPackedAccess()108 public void testPackedAccess() { 109 ValueLayout vChar = MemoryLayouts.BITS_8_BE; 110 ValueLayout vShort = MemoryLayouts.BITS_16_BE; 111 ValueLayout vInt = MemoryLayouts.BITS_32_BE; 112 //mimic pragma pack(1) 113 GroupLayout g = MemoryLayout.ofStruct(vChar.withBitAlignment(8).withName("a"), 114 vShort.withBitAlignment(8).withName("b"), 115 vInt.withBitAlignment(8).withName("c")); 116 assertEquals(g.bitAlignment(), 8); 117 VarHandle vh_c = g.varHandle(byte.class, PathElement.groupElement("a")); 118 VarHandle vh_s = g.varHandle(short.class, PathElement.groupElement("b")); 119 VarHandle vh_i = g.varHandle(int.class, PathElement.groupElement("c")); 120 try (MemorySegment segment = MemorySegment.allocateNative(g)) { 121 MemoryAddress addr = segment.baseAddress(); 122 vh_c.set(addr, Byte.MIN_VALUE); 123 assertEquals(vh_c.get(addr), Byte.MIN_VALUE); 124 vh_s.set(addr, Short.MIN_VALUE); 125 assertEquals(vh_s.get(addr), Short.MIN_VALUE); 126 vh_i.set(addr, Integer.MIN_VALUE); 127 assertEquals(vh_i.get(addr), Integer.MIN_VALUE); 128 } 129 } 130 131 @DataProvider(name = "alignments") createAlignments()132 public Object[][] createAlignments() { 133 return LongStream.range(3, 32) 134 .mapToObj(v -> new Object[] { 1L << v }) 135 .toArray(Object[][]::new); 136 } 137 } 138