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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
| author | trims |
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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 |
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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 } |