Mercurial > hg > truffle
comparison graal/com.oracle.jvmci.meta/src/com/oracle/jvmci/meta/LocationIdentity.java @ 21556:48c1ebd24120
renamed com.oracle.graal.api[meta|code] modules to com.oracle.jvmci.[meta|code] (JBS:GRAAL-53)
author | Doug Simon <doug.simon@oracle.com> |
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date | Wed, 27 May 2015 00:36:16 +0200 |
parents | graal/com.oracle.graal.api.meta/src/com/oracle/graal/api/meta/LocationIdentity.java@f9024b74dd9e |
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21555:d12eaef9af72 | 21556:48c1ebd24120 |
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1 /* | |
2 * Copyright (c) 2011, 2012, 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 package com.oracle.jvmci.meta; | |
24 | |
25 import java.util.*; | |
26 | |
27 // JaCoCo Exclude | |
28 | |
29 /** | |
30 * Marker interface for location identities. Apart from the special values {@link #ANY_LOCATION} and | |
31 * {@link #FINAL_LOCATION}, a different location identity of two memory accesses guarantees that the | |
32 * two accesses do not interfere. | |
33 * | |
34 * Clients of {@link LocationIdentity} must use {@link #equals(Object)}, not {@code ==}, when | |
35 * comparing two {@link LocationIdentity} values for equality. Likewise, they must not use | |
36 * {@link IdentityHashMap}s with {@link LocationIdentity} values as keys. | |
37 */ | |
38 public abstract class LocationIdentity { | |
39 | |
40 /** | |
41 * Denotes any location. A write to such a location kills all values in a memory map during an | |
42 * analysis of memory accesses. A read from this location cannot be moved or coalesced with | |
43 * other reads because its interaction with other reads is not known. | |
44 */ | |
45 private static final LocationIdentity ANY_LOCATION = NamedLocationIdentity.mutable("ANY_LOCATION"); | |
46 | |
47 /** | |
48 * Denotes the location of a value that is guaranteed to be unchanging. | |
49 */ | |
50 public static final LocationIdentity FINAL_LOCATION = NamedLocationIdentity.immutable("FINAL_LOCATION"); | |
51 | |
52 /** | |
53 * Denotes the location of the length field of a Java array. | |
54 */ | |
55 public static final LocationIdentity ARRAY_LENGTH_LOCATION = NamedLocationIdentity.immutable("[].length"); | |
56 | |
57 public static LocationIdentity any() { | |
58 return ANY_LOCATION; | |
59 } | |
60 | |
61 /** | |
62 * Denotes a location is unchanging in all cases. Not that this is different than the Java | |
63 * notion of final which only requires definite assignment. | |
64 */ | |
65 public abstract boolean isImmutable(); | |
66 | |
67 public final boolean isMutable() { | |
68 return !isImmutable(); | |
69 } | |
70 | |
71 public final boolean isAny() { | |
72 return this == ANY_LOCATION; | |
73 } | |
74 | |
75 public final boolean isSingle() { | |
76 return this != ANY_LOCATION; | |
77 } | |
78 | |
79 public final boolean overlaps(LocationIdentity other) { | |
80 return isAny() || other.isAny() || this.equals(other); | |
81 } | |
82 } |