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comparison graal/com.oracle.jvmci.asm/src/com/oracle/jvmci/asm/Label.java @ 21708:6df25b1418be

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moved com.oracle.asm.** to jvmci-util.jar (JBS:GRAAL-53)
author Doug Simon <doug.simon@oracle.com>
date Wed, 03 Jun 2015 18:06:44 +0200
parents graal/com.oracle.graal.asm/src/com/oracle/graal/asm/Label.java@5a7b82c1514e
children
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equal deleted inserted replaced
21707:e0f311284930 21708:6df25b1418be
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.oracle.jvmci.asm;
24
25 import java.util.*;
26
27 /**
28 * This class represents a label within assembly code.
29 */
30 public final class Label {
31
32 private int position = -1;
33 private int blockId = -1;
34
35 /**
36 * References to instructions that jump to this unresolved label. These instructions need to be
37 * patched when the label is bound using the {@link #patchInstructions(Assembler)} method.
38 */
39 private ArrayList<Integer> patchPositions = null;
40
41 /**
42 * Returns the position of this label in the code buffer.
43 *
44 * @return the position
45 */
46 public int position() {
47 assert position >= 0 : "Unbound label is being referenced";
48 return position;
49 }
50
51 public Label() {
52 }
53
54 public Label(int id) {
55 blockId = id;
56 }
57
58 public int getBlockId() {
59 return blockId;
60 }
61
62 /**
63 * Binds the label to the specified position.
64 *
65 * @param pos the position
66 */
67 protected void bind(int pos) {
68 this.position = pos;
69 assert isBound();
70 }
71
72 public boolean isBound() {
73 return position >= 0;
74 }
75
76 public void addPatchAt(int branchLocation) {
77 assert !isBound() : "Label is already bound " + this + " " + branchLocation + " at position " + position;
78 if (patchPositions == null) {
79 patchPositions = new ArrayList<>(2);
80 }
81 patchPositions.add(branchLocation);
82 }
83
84 protected void patchInstructions(Assembler masm) {
85 assert isBound() : "Label should be bound";
86 if (patchPositions != null) {
87 int target = position;
88 for (int i = 0; i < patchPositions.size(); ++i) {
89 int pos = patchPositions.get(i);
90 masm.patchJumpTarget(pos, target);
91 }
92 }
93 }
94
95 public void reset() {
96 if (this.patchPositions != null) {
97 this.patchPositions.clear();
98 }
99 this.position = -1;
100 }
101
102 @Override
103 public String toString() {
104 return isBound() ? String.valueOf(position()) : "?";
105 }
106 }