Mercurial > hg > graal-compiler
comparison graal/GraalCompiler/src/com/sun/c1x/ir/StateSplit.java @ 2509:16b9a8b5ad39
Renamings Runtime=>GraalRuntime and Compiler=>GraalCompiler
author | Thomas Wuerthinger <thomas@wuerthinger.net> |
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date | Wed, 27 Apr 2011 11:50:44 +0200 |
parents | graal/Compiler/src/com/sun/c1x/ir/StateSplit.java@9ec15d6914ca |
children | c58a301eb2d7 |
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2508:fea94949e0a2 | 2509:16b9a8b5ad39 |
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1 /* | |
2 * Copyright (c) 2009, 2011, 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.sun.c1x.ir; | |
24 | |
25 import com.sun.c1x.value.*; | |
26 import com.sun.cri.ci.*; | |
27 | |
28 /** | |
29 * The {@code StateSplit} class is the abstract base class of all instructions | |
30 * that store an immutable copy of the frame state. | |
31 * | |
32 * @author Ben L. Titzer | |
33 */ | |
34 public abstract class StateSplit extends Instruction { | |
35 | |
36 /** | |
37 * Sentinel denoting an explicitly cleared state. | |
38 */ | |
39 private static final FrameState CLEARED_STATE = new MutableFrameState(null, -5, 0, 0); | |
40 | |
41 private FrameState stateBefore; | |
42 | |
43 /** | |
44 * Creates a new state split with the specified value type. | |
45 * @param kind the type of the value that this instruction produces | |
46 */ | |
47 public StateSplit(CiKind kind, FrameState stateBefore) { | |
48 super(kind); | |
49 this.stateBefore = stateBefore; | |
50 } | |
51 | |
52 /** | |
53 * Determines if the state for this instruction has explicitly | |
54 * been cleared (as opposed to never initialized). Once explicitly | |
55 * cleared, an instruction must not have it state (re)set. | |
56 */ | |
57 public boolean isStateCleared() { | |
58 return stateBefore == CLEARED_STATE; | |
59 } | |
60 | |
61 /** | |
62 * Clears the state for this instruction. Once explicitly | |
63 * cleared, an instruction must not have it state (re)set. | |
64 */ | |
65 protected void clearState() { | |
66 stateBefore = CLEARED_STATE; | |
67 } | |
68 | |
69 /** | |
70 * Records the state of this instruction before it is executed. | |
71 * | |
72 * @param stateBefore the state | |
73 */ | |
74 public final void setStateBefore(FrameState stateBefore) { | |
75 assert this.stateBefore == null; | |
76 this.stateBefore = stateBefore; | |
77 } | |
78 | |
79 /** | |
80 * Gets the state for this instruction. | |
81 * @return the state | |
82 */ | |
83 @Override | |
84 public final FrameState stateBefore() { | |
85 return stateBefore == CLEARED_STATE ? null : stateBefore; | |
86 } | |
87 } |