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annotate agent/src/share/classes/sun/jvm/hotspot/runtime/amd64/AMD64CurrentFrameGuess.java @ 1552:c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair
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date | Thu, 27 May 2010 19:08:38 -0700 |
parents | a61af66fc99e |
children | 7588156f5cf9 |
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0 | 1 /* |
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2 * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 package sun.jvm.hotspot.runtime.amd64; | |
26 | |
27 import sun.jvm.hotspot.debugger.*; | |
28 import sun.jvm.hotspot.debugger.amd64.*; | |
29 import sun.jvm.hotspot.code.*; | |
30 import sun.jvm.hotspot.interpreter.*; | |
31 import sun.jvm.hotspot.runtime.*; | |
32 | |
33 /** <P> Should be able to be used on all amd64 platforms we support | |
34 (Linux/amd64) to implement JavaThread's | |
35 "currentFrameGuess()" functionality. Input is an AMD64ThreadContext; | |
36 output is SP, FP, and PC for an AMD64Frame. Instantiation of the | |
37 AMD64Frame is left to the caller, since we may need to subclass | |
38 AMD64Frame to support signal handler frames on Unix platforms. </P> | |
39 | |
40 <P> Algorithm is to walk up the stack within a given range (say, | |
41 512K at most) looking for a plausible PC and SP for a Java frame, | |
42 also considering those coming in from the context. If we find a PC | |
43 that belongs to the VM (i.e., in generated code like the | |
44 interpreter or CodeCache) then we try to find an associated EBP. | |
45 We repeat this until we either find a complete frame or run out of | |
46 stack to look at. </P> */ | |
47 | |
48 public class AMD64CurrentFrameGuess { | |
49 private AMD64ThreadContext context; | |
50 private JavaThread thread; | |
51 private Address spFound; | |
52 private Address fpFound; | |
53 private Address pcFound; | |
54 | |
55 private static final boolean DEBUG = System.getProperty("sun.jvm.hotspot.runtime.amd64.AMD64Frame.DEBUG") | |
56 != null; | |
57 | |
58 public AMD64CurrentFrameGuess(AMD64ThreadContext context, | |
59 JavaThread thread) { | |
60 this.context = context; | |
61 this.thread = thread; | |
62 } | |
63 | |
64 /** Returns false if not able to find a frame within a reasonable range. */ | |
65 public boolean run(long regionInBytesToSearch) { | |
66 Address sp = context.getRegisterAsAddress(AMD64ThreadContext.RSP); | |
67 Address pc = context.getRegisterAsAddress(AMD64ThreadContext.RIP); | |
68 Address fp = context.getRegisterAsAddress(AMD64ThreadContext.RBP); | |
69 if (sp == null) { | |
70 // Bail out if no last java frame either | |
71 if (thread.getLastJavaSP() != null) { | |
72 setValues(thread.getLastJavaSP(), thread.getLastJavaFP(), null); | |
73 return true; | |
74 } | |
75 return false; | |
76 } | |
77 Address end = sp.addOffsetTo(regionInBytesToSearch); | |
78 VM vm = VM.getVM(); | |
79 | |
80 setValues(null, null, null); // Assume we're not going to find anything | |
81 | |
82 if (vm.isJavaPCDbg(pc)) { | |
83 if (vm.isClientCompiler()) { | |
84 // If the topmost frame is a Java frame, we are (pretty much) | |
85 // guaranteed to have a viable EBP. We should be more robust | |
86 // than this (we have the potential for losing entire threads' | |
87 // stack traces) but need to see how much work we really have | |
88 // to do here. Searching the stack for an (SP, FP) pair is | |
89 // hard since it's easy to misinterpret inter-frame stack | |
90 // pointers as base-of-frame pointers; we also don't know the | |
91 // sizes of C1 frames (not registered in the nmethod) so can't | |
92 // derive them from ESP. | |
93 | |
94 setValues(sp, fp, pc); | |
95 return true; | |
96 } else { | |
97 if (vm.getInterpreter().contains(pc)) { | |
98 if (DEBUG) { | |
99 System.out.println("CurrentFrameGuess: choosing interpreter frame: sp = " + | |
100 sp + ", fp = " + fp + ", pc = " + pc); | |
101 } | |
102 setValues(sp, fp, pc); | |
103 return true; | |
104 } | |
105 | |
106 // For the server compiler, EBP is not guaranteed to be valid | |
107 // for compiled code. In addition, an earlier attempt at a | |
108 // non-searching algorithm (see below) failed because the | |
109 // stack pointer from the thread context was pointing | |
110 // (considerably) beyond the ostensible end of the stack, into | |
111 // garbage; walking from the topmost frame back caused a crash. | |
112 // | |
113 // This algorithm takes the current PC as a given and tries to | |
114 // find the correct corresponding SP by walking up the stack | |
115 // and repeatedly performing stackwalks (very inefficient). | |
116 // | |
117 // FIXME: there is something wrong with stackwalking across | |
118 // adapter frames...this is likely to be the root cause of the | |
119 // failure with the simpler algorithm below. | |
120 | |
121 for (long offset = 0; | |
122 offset < regionInBytesToSearch; | |
123 offset += vm.getAddressSize()) { | |
124 try { | |
125 Address curSP = sp.addOffsetTo(offset); | |
126 Frame frame = new AMD64Frame(curSP, null, pc); | |
127 RegisterMap map = thread.newRegisterMap(false); | |
128 while (frame != null) { | |
129 if (frame.isEntryFrame() && frame.entryFrameIsFirst()) { | |
130 // We were able to traverse all the way to the | |
131 // bottommost Java frame. | |
132 // This sp looks good. Keep it. | |
133 if (DEBUG) { | |
134 System.out.println("CurrentFrameGuess: Choosing sp = " + curSP + ", pc = " + pc); | |
135 } | |
136 setValues(curSP, null, pc); | |
137 return true; | |
138 } | |
139 frame = frame.sender(map); | |
140 } | |
141 } catch (Exception e) { | |
142 if (DEBUG) { | |
143 System.out.println("CurrentFrameGuess: Exception " + e + " at offset " + offset); | |
144 } | |
145 // Bad SP. Try another. | |
146 } | |
147 } | |
148 | |
149 // Were not able to find a plausible SP to go with this PC. | |
150 // Bail out. | |
151 return false; | |
152 | |
153 /* | |
154 // Original algorithm which does not work because SP was | |
155 // pointing beyond where it should have: | |
156 | |
157 // For the server compiler, EBP is not guaranteed to be valid | |
158 // for compiled code. We see whether the PC is in the | |
159 // interpreter and take care of that, otherwise we run code | |
160 // (unfortunately) duplicated from AMD64Frame.senderForCompiledFrame. | |
161 | |
162 CodeCache cc = vm.getCodeCache(); | |
163 if (cc.contains(pc)) { | |
164 CodeBlob cb = cc.findBlob(pc); | |
165 | |
166 // See if we can derive a frame pointer from SP and PC | |
167 // NOTE: This is the code duplicated from AMD64Frame | |
168 Address saved_fp = null; | |
169 int llink_offset = cb.getLinkOffset(); | |
170 if (llink_offset >= 0) { | |
171 // Restore base-pointer, since next frame might be an interpreter frame. | |
172 Address fp_addr = sp.addOffsetTo(VM.getVM().getAddressSize() * llink_offset); | |
173 saved_fp = fp_addr.getAddressAt(0); | |
174 } | |
175 | |
176 setValues(sp, saved_fp, pc); | |
177 return true; | |
178 } | |
179 */ | |
180 } | |
181 } else { | |
182 // If the current program counter was not known to us as a Java | |
183 // PC, we currently assume that we are in the run-time system | |
184 // and attempt to look to thread-local storage for saved ESP and | |
185 // EBP. Note that if these are null (because we were, in fact, | |
186 // in Java code, i.e., vtable stubs or similar, and the SA | |
187 // didn't have enough insight into the target VM to understand | |
188 // that) then we are going to lose the entire stack trace for | |
189 // the thread, which is sub-optimal. FIXME. | |
190 | |
191 if (DEBUG) { | |
192 System.out.println("CurrentFrameGuess: choosing last Java frame: sp = " + | |
193 thread.getLastJavaSP() + ", fp = " + thread.getLastJavaFP()); | |
194 } | |
195 if (thread.getLastJavaSP() == null) { | |
196 return false; // No known Java frames on stack | |
197 } | |
198 setValues(thread.getLastJavaSP(), thread.getLastJavaFP(), null); | |
199 return true; | |
200 } | |
201 } | |
202 | |
203 public Address getSP() { return spFound; } | |
204 public Address getFP() { return fpFound; } | |
205 /** May be null if getting values from thread-local storage; take | |
206 care to call the correct AMD64Frame constructor to recover this if | |
207 necessary */ | |
208 public Address getPC() { return pcFound; } | |
209 | |
210 private void setValues(Address sp, Address fp, Address pc) { | |
211 spFound = sp; | |
212 fpFound = fp; | |
213 pcFound = pc; | |
214 } | |
215 } |