1 /*
   2  * Copyright (c) 2000, 2018, 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  */
  24 
  25 package sun.jvm.hotspot.utilities;
  26 
  27 import sun.jvm.hotspot.code.*;
  28 import sun.jvm.hotspot.debugger.*;
  29 import sun.jvm.hotspot.gc.shared.*;
  30 import sun.jvm.hotspot.interpreter.*;
  31 import sun.jvm.hotspot.runtime.*;
  32 import sun.jvm.hotspot.memory.*;
  33 
  34 /** This class, only intended for use in the debugging system,
  35     provides the functionality of find() in the VM. */
  36 
  37 public class PointerFinder {
  38   public static PointerLocation find(Address a) {
  39     PointerLocation loc = new PointerLocation(a);
  40 
  41     CollectedHeap heap = VM.getVM().getUniverse().heap();
  42     if (heap instanceof GenCollectedHeap) {
  43       GenCollectedHeap genheap = (GenCollectedHeap) heap;
  44       if (genheap.isIn(a)) {
  45         for (int i = 0; i < genheap.nGens(); i++) {
  46           Generation g = genheap.getGen(i);
  47           if (g.isIn(a)) {
  48             loc.gen = g;
  49             break;
  50           }
  51         }
  52 
  53           if (Assert.ASSERTS_ENABLED) {
  54           Assert.that(loc.gen != null, "Should have found this in a generation");
  55         }
  56 
  57         if (VM.getVM().getUseTLAB()) {
  58           // Try to find thread containing it
  59           for (JavaThread t = VM.getVM().getThreads().first(); t != null; t = t.next()) {
  60             ThreadLocalAllocBuffer tlab = t.tlab();
  61             if (tlab.contains(a)) {
  62               loc.inTLAB = true;
  63               loc.tlabThread = t;
  64               loc.tlab = tlab;
  65               break;
  66             }
  67           }
  68         }
  69 
  70         return loc;
  71       }
  72     } else {
  73       if (heap.isIn(a)) {
  74         loc.heap = heap;
  75         return loc;
  76       }
  77     }
  78 
  79     Interpreter interp = VM.getVM().getInterpreter();
  80     if (interp.contains(a)) {
  81       loc.inInterpreter = true;
  82       loc.interpreterCodelet = interp.getCodeletContaining(a);
  83       return loc;
  84     }
  85 
  86     if (!VM.getVM().isCore()) {
  87       CodeCache c = VM.getVM().getCodeCache();
  88       if (c.contains(a)) {
  89         loc.inCodeCache = true;
  90         loc.blob = c.findBlobUnsafe(a);
  91         if (Assert.ASSERTS_ENABLED) {
  92           Assert.that(loc.blob != null, "Should have found CodeBlob");
  93         }
  94         loc.inBlobCode = loc.blob.codeContains(a);
  95         loc.inBlobData = loc.blob.dataContains(a);
  96 
  97         if (loc.blob.isNMethod()) {
  98             NMethod nm = (NMethod) loc.blob;
  99             loc.inBlobOops = nm.oopsContains(a);
 100         }
 101 
 102         loc.inBlobUnknownLocation = (!(loc.inBlobCode ||
 103                                        loc.inBlobData ||
 104                                        loc.inBlobOops));
 105         return loc;
 106       }
 107     }
 108 
 109     // Check JNIHandles; both local and global
 110     JNIHandles handles = VM.getVM().getJNIHandles();
 111 
 112     // --- looking in oopstorage should model OopStorage::allocation_status?
 113     // --- that is, if in a block but not allocated, then not valid.
 114 
 115     // Look in global handles
 116     OopStorage storage = handles.globalHandles();
 117     if ((storage != null) && storage.findOop(a)) {
 118       loc.inStrongGlobalJNIHandles = true;
 119       return loc;
 120     }
 121     // Look in weak global handles
 122     storage = handles.weakGlobalHandles();
 123     if ((storage != null) && storage.findOop(a)) {
 124       loc.inWeakGlobalJNIHandles = true;
 125       return loc;
 126     }
 127     // Look in thread-local handles
 128     for (JavaThread t = VM.getVM().getThreads().first(); t != null; t = t.next()) {
 129       JNIHandleBlock handleBlock = t.activeHandles();
 130       if (handleBlock != null) {
 131         handleBlock = handleBlock.blockContainingHandle(a);
 132         if (handleBlock != null) {
 133           loc.inLocalJNIHandleBlock = true;
 134           loc.handleBlock = handleBlock;
 135           loc.handleThread = t;
 136           return loc;
 137         }
 138       }
 139     }
 140 
 141     // Fall through; have to return it anyway.
 142     return loc;
 143   }
 144 }