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comparison agent/src/share/classes/sun/jvm/hotspot/runtime/StackFrameStream.java @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 2000-2004 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 package sun.jvm.hotspot.runtime;
26
27 import sun.jvm.hotspot.utilities.*;
28
29 /** <P> StackFrameStream iterates through the frames of a thread
30 starting from top most frame. It automatically takes care of
31 updating the location of all (callee-saved) registers. Notice: If
32 a thread is stopped at a safepoint, all registers are saved, not
33 only the callee-saved ones. </P>
34
35 <P> Use: </P>
36
37 <PRE>
38 for(StackFrameStream fst = new StackFrameStream(thread); !fst.isDone(); fst.next()) {
39 ...
40 }
41 </PRE>
42 */
43
44 public class StackFrameStream {
45 private Frame fr;
46 private RegisterMap regMap;
47 private boolean isDone;
48
49 /** Equivalent to StackFrameStream(thread, true) */
50 public StackFrameStream(JavaThread thread) {
51 this(thread, true);
52 }
53
54 public StackFrameStream(JavaThread thread, boolean update) {
55 if (!VM.getVM().isDebugging()) {
56 if (Assert.ASSERTS_ENABLED) {
57 Assert.that(thread.hasLastJavaFrame(), "sanity check");
58 }
59 fr = thread.getLastFrame();
60 regMap = thread.newRegisterMap(update);
61 isDone = false;
62 } else {
63 // Special case code to find the topmost Java frame
64 // FIXME: should check to see whether we're at safepoint, and if
65 // so, skip the "current frame guess" call and unnecessary
66 // stackwalking work
67 fr = thread.getCurrentFrameGuess();
68 regMap = thread.newRegisterMap(update);
69 while ((fr != null) && (!fr.isJavaFrame())) {
70 if (fr.isFirstFrame()) {
71 fr = null;
72 } else {
73 fr = fr.sender(regMap);
74 }
75 }
76 if (fr == null) {
77 isDone = true;
78 }
79 }
80 }
81
82 /** Iteration */
83 public boolean isDone() {
84 if (isDone) {
85 return true;
86 } else {
87 if (fr == null) {
88 isDone = true;
89 return true;
90 }
91 isDone = fr.isFirstFrame();
92 return false;
93 }
94 }
95
96 public void next() {
97 if (!isDone) {
98 fr = fr.sender(regMap);
99 }
100 }
101
102 /** Query */
103 public Frame getCurrent() { return fr; }
104 public RegisterMap getRegisterMap() { return regMap; }
105 }