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comparison graal/GraalCompiler/src/com/sun/c1x/ir/StateSplit.java @ 2509:16b9a8b5ad39

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Renamings Runtime=>GraalRuntime and Compiler=>GraalCompiler
author Thomas Wuerthinger <thomas@wuerthinger.net>
date Wed, 27 Apr 2011 11:50:44 +0200
parents graal/Compiler/src/com/sun/c1x/ir/StateSplit.java@9ec15d6914ca
children c58a301eb2d7
comparison
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2508:fea94949e0a2 2509:16b9a8b5ad39
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 }