Mercurial > hg > graal-compiler
comparison graal/com.oracle.jvmci.asm/src/com/oracle/jvmci/asm/Label.java @ 21708:6df25b1418be
moved com.oracle.asm.** to jvmci-util.jar (JBS:GRAAL-53)
author | Doug Simon <doug.simon@oracle.com> |
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date | Wed, 03 Jun 2015 18:06:44 +0200 |
parents | graal/com.oracle.graal.asm/src/com/oracle/graal/asm/Label.java@5a7b82c1514e |
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21707:e0f311284930 | 21708:6df25b1418be |
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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.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 } |