1 /*

     2  * Copyright (c) 1997, 2014, 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.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 

    27 /*

    28  * The Original Code is HAT. The Initial Developer of the

    29  * Original Code is Bill Foote, with contributions from others

    30  * at JavaSoft/Sun.

    31  */

    32 

    33 package com.sun.tools.hat.internal.model;

    34 

    35 import java.lang.ref.SoftReference;

    36 import java.util.*;

    37 import com.sun.tools.hat.internal.parser.ReadBuffer;

    38 import com.sun.tools.hat.internal.util.Misc;

    39 

    40 /**

    41  *

    42  * @author      Bill Foote

    43  */

    44 

    45 /**

    46  * Represents a snapshot of the Java objects in the VM at one instant.

    47  * This is the top-level "model" object read out of a single .hprof or .bod

    48  * file.

    49  */

    50 

    51 public class Snapshot {

    52 

    53     public static long SMALL_ID_MASK = 0x0FFFFFFFFL;

    54     public static final byte[] EMPTY_BYTE_ARRAY = new byte[0];

    55 

    56     private static final JavaField[] EMPTY_FIELD_ARRAY = new JavaField[0];

    57     private static final JavaStatic[] EMPTY_STATIC_ARRAY = new JavaStatic[0];

    58 

    59     // all heap objects

    60     private Hashtable<Number, JavaHeapObject> heapObjects =

    61                  new Hashtable<Number, JavaHeapObject>();

    62 

    63     private Hashtable<Number, JavaClass> fakeClasses =

    64                  new Hashtable<Number, JavaClass>();

    65 

    66     // all Roots in this Snapshot

    67     private Vector<Root> roots = new Vector<Root>();

    68 

    69     // name-to-class map

    70     private Map<String, JavaClass> classes =

    71                  new TreeMap<String, JavaClass>();

    72 

    73     // new objects relative to a baseline - lazily initialized

    74     private volatile Map<JavaHeapObject, Boolean> newObjects;

    75 

    76     // allocation site traces for all objects - lazily initialized

    77     private volatile Map<JavaHeapObject, StackTrace> siteTraces;

    78 

    79     // object-to-Root map for all objects

    80     private Map<JavaHeapObject, Root> rootsMap =

    81                  new HashMap<JavaHeapObject, Root>();

    82 

    83     // soft cache of finalizeable objects - lazily initialized

    84     private SoftReference<Vector<?>> finalizablesCache;

    85 

    86     // represents null reference

    87     private JavaThing nullThing;

    88 

    89     // java.lang.ref.Reference class

    90     private JavaClass weakReferenceClass;

    91     // index of 'referent' field in java.lang.ref.Reference class

    92     private int referentFieldIndex;

    93 

    94     // java.lang.Class class

    95     private JavaClass javaLangClass;

    96     // java.lang.String class

    97     private JavaClass javaLangString;

    98     // java.lang.ClassLoader class

    99     private JavaClass javaLangClassLoader;

   100 

   101     // unknown "other" array class

   102     private volatile JavaClass otherArrayType;

   103     // Stuff to exclude from reachable query

   104     private ReachableExcludes reachableExcludes;

   105     // the underlying heap dump buffer

   106     private ReadBuffer readBuf;

   107 

   108     // True iff some heap objects have isNew set

   109     private boolean hasNewSet;

   110     private boolean unresolvedObjectsOK;

   111 

   112     // whether object array instances have new style class or

   113     // old style (element) class.

   114     private boolean newStyleArrayClass;

   115 

   116     // object id size in the heap dump

   117     private int identifierSize = 4;

   118 

   119     // minimum object size - accounts for object header in

   120     // most Java virtual machines - we assume 2 identifierSize

   121     // (which is true for Sun's hotspot JVM).

   122     private int minimumObjectSize;

   123 

   124     public Snapshot(ReadBuffer buf) {

   125         nullThing = new HackJavaValue("<null>", 0);

   126         readBuf = buf;

   127     }

   128 

   129     public void setSiteTrace(JavaHeapObject obj, StackTrace trace) {

   130         if (trace != null && trace.getFrames().length != 0) {

   131             initSiteTraces();

   132             siteTraces.put(obj, trace);

   133         }

   134     }

   135 

   136     public StackTrace getSiteTrace(JavaHeapObject obj) {

   137         if (siteTraces != null) {

   138             return siteTraces.get(obj);

   139         } else {

   140             return null;

   141         }

   142     }

   143 

   144     public void setNewStyleArrayClass(boolean value) {

   145         newStyleArrayClass = value;

   146     }

   147 

   148     public boolean isNewStyleArrayClass() {

   149         return newStyleArrayClass;

   150     }

   151 

   152     public void setIdentifierSize(int size) {

   153         identifierSize = size;

   154         minimumObjectSize = 2 * size;

   155     }

   156 

   157     public int getIdentifierSize() {

   158         return identifierSize;

   159     }

   160 

   161     public int getMinimumObjectSize() {

   162         return minimumObjectSize;

   163     }

   164 

   165     public void addHeapObject(long id, JavaHeapObject ho) {

   166         heapObjects.put(makeId(id), ho);

   167     }

   168 

   169     public void addRoot(Root r) {

   170         r.setIndex(roots.size());

   171         roots.addElement(r);

   172     }

   173 

   174     public void addClass(long id, JavaClass c) {

   175         addHeapObject(id, c);

   176         putInClassesMap(c);

   177     }

   178 

   179     JavaClass addFakeInstanceClass(long classID, int instSize) {

   180         // Create a fake class name based on ID.

   181         String name = "unknown-class<@" + Misc.toHex(classID) + ">";

   182 

   183         // Create fake fields convering the given instance size.

   184         // Create as many as int type fields and for the left over

   185         // size create byte type fields.

   186         int numInts = instSize / 4;

   187         int numBytes = instSize % 4;

   188         JavaField[] fields = new JavaField[numInts + numBytes];

   189         int i;

   190         for (i = 0; i < numInts; i++) {

   191             fields[i] = new JavaField("unknown-field-" + i, "I");

   192         }

   193         for (i = 0; i < numBytes; i++) {

   194             fields[i + numInts] = new JavaField("unknown-field-" +

   195                                                 i + numInts, "B");

   196         }

   197 

   198         // Create fake instance class

   199         JavaClass c = new JavaClass(name, 0, 0, 0, 0, fields,

   200                                  EMPTY_STATIC_ARRAY, instSize);

   201         // Add the class

   202         addFakeClass(makeId(classID), c);

   203         return c;

   204     }

   205 

   206 

   207     /**

   208      * @return true iff it's possible that some JavaThing instances might

   209      *          isNew set

   210      *

   211      * @see JavaThing.isNew()

   212      */

   213     public boolean getHasNewSet() {

   214         return hasNewSet;

   215     }

   216 

   217     //

   218     // Used in the body of resolve()

   219     //

   220     private static class MyVisitor extends AbstractJavaHeapObjectVisitor {

   221         JavaHeapObject t;

   222         public void visit(JavaHeapObject other) {

   223             other.addReferenceFrom(t);

   224         }

   225     }

   226 

   227     // To show heap parsing progress, we print a '.' after this limit

   228     private static final int DOT_LIMIT = 5000;

   229 

   230     /**

   231      * Called after reading complete, to initialize the structure

   232      */

   233     public void resolve(boolean calculateRefs) {

   234         System.out.println("Resolving " + heapObjects.size() + " objects...");

   235 

   236         // First, resolve the classes.  All classes must be resolved before

   237         // we try any objects, because the objects use classes in their

   238         // resolution.

   239         javaLangClass = findClass("java.lang.Class");

   240         if (javaLangClass == null) {

   241             System.out.println("WARNING:  hprof file does not include java.lang.Class!");

   242             javaLangClass = new JavaClass("java.lang.Class", 0, 0, 0, 0,

   243                                  EMPTY_FIELD_ARRAY, EMPTY_STATIC_ARRAY, 0);

   244             addFakeClass(javaLangClass);

   245         }

   246         javaLangString = findClass("java.lang.String");

   247         if (javaLangString == null) {

   248             System.out.println("WARNING:  hprof file does not include java.lang.String!");

   249             javaLangString = new JavaClass("java.lang.String", 0, 0, 0, 0,

   250                                  EMPTY_FIELD_ARRAY, EMPTY_STATIC_ARRAY, 0);

   251             addFakeClass(javaLangString);

   252         }

   253         javaLangClassLoader = findClass("java.lang.ClassLoader");

   254         if (javaLangClassLoader == null) {

   255             System.out.println("WARNING:  hprof file does not include java.lang.ClassLoader!");

   256             javaLangClassLoader = new JavaClass("java.lang.ClassLoader", 0, 0, 0, 0,

   257                                  EMPTY_FIELD_ARRAY, EMPTY_STATIC_ARRAY, 0);

   258             addFakeClass(javaLangClassLoader);

   259         }

   260 

   261         for (JavaHeapObject t : heapObjects.values()) {

   262             if (t instanceof JavaClass) {

   263                 t.resolve(this);

   264             }

   265         }

   266 

   267         // Now, resolve everything else.

   268         for (JavaHeapObject t : heapObjects.values()) {

   269             if (!(t instanceof JavaClass)) {

   270                 t.resolve(this);

   271             }

   272         }

   273 

   274         heapObjects.putAll(fakeClasses);

   275         fakeClasses.clear();

   276 

   277         weakReferenceClass = findClass("java.lang.ref.Reference");

   278         if (weakReferenceClass == null)  {      // JDK 1.1.x

   279             weakReferenceClass = findClass("sun.misc.Ref");

   280             referentFieldIndex = 0;

   281         } else {

   282             JavaField[] fields = weakReferenceClass.getFieldsForInstance();

   283             for (int i = 0; i < fields.length; i++) {

   284                 if ("referent".equals(fields[i].getName())) {

   285                     referentFieldIndex = i;

   286                     break;

   287                 }

   288             }

   289         }

   290 

   291         if (calculateRefs) {

   292             calculateReferencesToObjects();

   293             System.out.print("Eliminating duplicate references");

   294             System.out.flush();

   295             // This println refers to the *next* step

   296         }

   297         int count = 0;

   298         for (JavaHeapObject t : heapObjects.values()) {

   299             t.setupReferers();

   300             ++count;

   301             if (calculateRefs && count % DOT_LIMIT == 0) {

   302                 System.out.print(".");

   303                 System.out.flush();

   304             }

   305         }

   306         if (calculateRefs) {

   307             System.out.println("");

   308         }

   309 

   310         // to ensure that Iterator.remove() on getClasses()

   311         // result will throw exception..

   312         classes = Collections.unmodifiableMap(classes);

   313     }

   314 

   315     private void calculateReferencesToObjects() {

   316         System.out.print("Chasing references, expect "

   317                          + (heapObjects.size() / DOT_LIMIT) + " dots");

   318         System.out.flush();

   319         int count = 0;

   320         MyVisitor visitor = new MyVisitor();

   321         for (JavaHeapObject t : heapObjects.values()) {

   322             visitor.t = t;

   323             // call addReferenceFrom(t) on all objects t references:

   324             t.visitReferencedObjects(visitor);

   325             ++count;

   326             if (count % DOT_LIMIT == 0) {

   327                 System.out.print(".");

   328                 System.out.flush();

   329             }

   330         }

   331         System.out.println();

   332         for (Root r : roots) {

   333             r.resolve(this);

   334             JavaHeapObject t = findThing(r.getId());

   335             if (t != null) {

   336                 t.addReferenceFromRoot(r);

   337             }

   338         }

   339     }

   340 

   341     public void markNewRelativeTo(Snapshot baseline) {

   342         hasNewSet = true;

   343         for (JavaHeapObject t : heapObjects.values()) {

   344             boolean isNew;

   345             long thingID = t.getId();

   346             if (thingID == 0L || thingID == -1L) {

   347                 isNew = false;

   348             } else {

   349                 JavaThing other = baseline.findThing(t.getId());

   350                 if (other == null) {

   351                     isNew = true;

   352                 } else {

   353                     isNew = !t.isSameTypeAs(other);

   354                 }

   355             }

   356             t.setNew(isNew);

   357         }

   358     }

   359 

   360     public Enumeration<JavaHeapObject> getThings() {

   361         return heapObjects.elements();

   362     }

   363 

   364 

   365     public JavaHeapObject findThing(long id) {

   366         Number idObj = makeId(id);

   367         JavaHeapObject jho = heapObjects.get(idObj);

   368         return jho != null? jho : fakeClasses.get(idObj);

   369     }

   370 

   371     public JavaHeapObject findThing(String id) {

   372         return findThing(Misc.parseHex(id));

   373     }

   374 

   375     public JavaClass findClass(String name) {

   376         if (name.startsWith("0x")) {

   377             return (JavaClass) findThing(name);

   378         } else {

   379             return classes.get(name);

   380         }

   381     }

   382 

   383     /**

   384      * Return an Iterator of all of the classes in this snapshot.

   385      **/

   386     public Iterator<JavaClass> getClasses() {

   387         // note that because classes is a TreeMap

   388         // classes are already sorted by name

   389         return classes.values().iterator();

   390     }

   391 

   392     public JavaClass[] getClassesArray() {

   393         JavaClass[] res = new JavaClass[classes.size()];

   394         classes.values().toArray(res);

   395         return res;

   396     }

   397 

   398     public synchronized Enumeration<?> getFinalizerObjects() {

   399         Vector<?> obj;

   400         if (finalizablesCache != null &&

   401             (obj = finalizablesCache.get()) != null) {

   402             return obj.elements();

   403         }

   404 

   405         JavaClass clazz = findClass("java.lang.ref.Finalizer");

   406         JavaObject queue = (JavaObject) clazz.getStaticField("queue");

   407         JavaThing tmp = queue.getField("head");

   408         Vector<JavaHeapObject> finalizables = new Vector<JavaHeapObject>();

   409         if (tmp != getNullThing()) {

   410             JavaObject head = (JavaObject) tmp;

   411             while (true) {

   412                 JavaHeapObject referent = (JavaHeapObject) head.getField("referent");

   413                 JavaThing next = head.getField("next");

   414                 if (next == getNullThing() || next.equals(head)) {

   415                     break;

   416                 }

   417                 head = (JavaObject) next;

   418                 finalizables.add(referent);

   419             }

   420         }

   421         finalizablesCache = new SoftReference<Vector<?>>(finalizables);

   422         return finalizables.elements();

   423     }

   424 

   425     public Enumeration<Root> getRoots() {

   426         return roots.elements();

   427     }

   428 

   429     public Root[] getRootsArray() {

   430         Root[] res = new Root[roots.size()];

   431         roots.toArray(res);

   432         return res;

   433     }

   434 

   435     public Root getRootAt(int i) {

   436         return roots.elementAt(i);

   437     }

   438 

   439     public ReferenceChain[]

   440     rootsetReferencesTo(JavaHeapObject target, boolean includeWeak) {

   441         Vector<ReferenceChain> fifo = new Vector<ReferenceChain>();  // This is slow... A real fifo would help

   442             // Must be a fifo to go breadth-first

   443         Hashtable<JavaHeapObject, JavaHeapObject> visited = new Hashtable<JavaHeapObject, JavaHeapObject>();

   444         // Objects are added here right after being added to fifo.

   445         Vector<ReferenceChain> result = new Vector<ReferenceChain>();

   446         visited.put(target, target);

   447         fifo.addElement(new ReferenceChain(target, null));

   448 

   449         while (fifo.size() > 0) {

   450             ReferenceChain chain = fifo.elementAt(0);

   451             fifo.removeElementAt(0);

   452             JavaHeapObject curr = chain.getObj();

   453             if (curr.getRoot() != null) {

   454                 result.addElement(chain);

   455                 // Even though curr is in the rootset, we want to explore its

   456                 // referers, because they might be more interesting.

   457             }

   458             Enumeration<JavaThing> referers = curr.getReferers();

   459             while (referers.hasMoreElements()) {

   460                 JavaHeapObject t = (JavaHeapObject) referers.nextElement();

   461                 if (t != null && !visited.containsKey(t)) {

   462                     if (includeWeak || !t.refersOnlyWeaklyTo(this, curr)) {

   463                         visited.put(t, t);

   464                         fifo.addElement(new ReferenceChain(t, chain));

   465                     }

   466                 }

   467             }

   468         }

   469 

   470         ReferenceChain[] realResult = new ReferenceChain[result.size()];

   471         for (int i = 0; i < result.size(); i++) {

   472             realResult[i] =  result.elementAt(i);

   473         }

   474         return realResult;

   475     }

   476 

   477     public boolean getUnresolvedObjectsOK() {

   478         return unresolvedObjectsOK;

   479     }

   480 

   481     public void setUnresolvedObjectsOK(boolean v) {

   482         unresolvedObjectsOK = v;

   483     }

   484 

   485     public JavaClass getWeakReferenceClass() {

   486         return weakReferenceClass;

   487     }

   488 

   489     public int getReferentFieldIndex() {

   490         return referentFieldIndex;

   491     }

   492 

   493     public JavaThing getNullThing() {

   494         return nullThing;

   495     }

   496 

   497     public void setReachableExcludes(ReachableExcludes e) {

   498         reachableExcludes = e;

   499     }

   500 

   501     public ReachableExcludes getReachableExcludes() {

   502         return reachableExcludes;

   503     }

   504 

   505     // package privates

   506     void addReferenceFromRoot(Root r, JavaHeapObject obj) {

   507         Root root = rootsMap.get(obj);

   508         if (root == null) {

   509             rootsMap.put(obj, r);

   510         } else {

   511             rootsMap.put(obj, root.mostInteresting(r));

   512         }

   513     }

   514 

   515     Root getRoot(JavaHeapObject obj) {

   516         return rootsMap.get(obj);

   517     }

   518 

   519     JavaClass getJavaLangClass() {

   520         return javaLangClass;

   521     }

   522 

   523     JavaClass getJavaLangString() {

   524         return javaLangString;

   525     }

   526 

   527     JavaClass getJavaLangClassLoader() {

   528         return javaLangClassLoader;

   529     }

   530 

   531     JavaClass getOtherArrayType() {

   532         if (otherArrayType == null) {

   533             synchronized(this) {

   534                 if (otherArrayType == null) {

   535                     addFakeClass(new JavaClass("[<other>", 0, 0, 0, 0,

   536                                      EMPTY_FIELD_ARRAY, EMPTY_STATIC_ARRAY,

   537                                      0));

   538                     otherArrayType = findClass("[<other>");

   539                 }

   540             }

   541         }

   542         return otherArrayType;

   543     }

   544 

   545     JavaClass getArrayClass(String elementSignature) {

   546         JavaClass clazz;

   547         synchronized(classes) {

   548             clazz = findClass("[" + elementSignature);

   549             if (clazz == null) {

   550                 clazz = new JavaClass("[" + elementSignature, 0, 0, 0, 0,

   551                                    EMPTY_FIELD_ARRAY, EMPTY_STATIC_ARRAY, 0);

   552                 addFakeClass(clazz);

   553                 // This is needed because the JDK only creates Class structures

   554                 // for array element types, not the arrays themselves.  For

   555                 // analysis, though, we need to pretend that there's a

   556                 // JavaClass for the array type, too.

   557             }

   558         }

   559         return clazz;

   560     }

   561 

   562     ReadBuffer getReadBuffer() {

   563         return readBuf;

   564     }

   565 

   566     void setNew(JavaHeapObject obj, boolean isNew) {

   567         initNewObjects();

   568         if (isNew) {

   569             newObjects.put(obj, Boolean.TRUE);

   570         }

   571     }

   572 

   573     boolean isNew(JavaHeapObject obj) {

   574         if (newObjects != null) {

   575             return newObjects.get(obj) != null;

   576         } else {

   577             return false;

   578         }

   579     }

   580 

   581     // Internals only below this point

   582     private Number makeId(long id) {

   583         if (identifierSize == 4) {

   584             return (int)id;

   585         } else {

   586             return id;

   587         }

   588     }

   589 

   590     private void putInClassesMap(JavaClass c) {

   591         String name = c.getName();

   592         if (classes.containsKey(name)) {

   593             // more than one class can have the same name

   594             // if so, create a unique name by appending

   595             // - and id string to it.

   596             name += "-" + c.getIdString();

   597         }

   598         classes.put(c.getName(), c);

   599     }

   600 

   601     private void addFakeClass(JavaClass c) {

   602         putInClassesMap(c);

   603         c.resolve(this);

   604     }

   605 

   606     private void addFakeClass(Number id, JavaClass c) {

   607         fakeClasses.put(id, c);

   608         addFakeClass(c);

   609     }

   610 

   611     private synchronized void initNewObjects() {

   612         if (newObjects == null) {

   613             synchronized (this) {

   614                 if (newObjects == null) {

   615                     newObjects = new HashMap<JavaHeapObject, Boolean>();

   616                 }

   617             }

   618         }

   619     }

   620 

   621     private synchronized void initSiteTraces() {

   622         if (siteTraces == null) {

   623             synchronized (this) {

   624                 if (siteTraces == null) {

   625                     siteTraces = new HashMap<JavaHeapObject, StackTrace>();

   626                 }

   627             }

   628         }

   629     }

   630 }