1 /*
   2  * Copyright (c) 2003, 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 //
  26 // Serviceability utility functions.
  27 // (Shared by MM and JVMTI).
  28 //
  29 class ServiceUtil : public AllStatic {
  30  public:
  31 
  32   // Return true if oop represents an object that is "visible"
  33   // to the java world.
  34   static inline bool visible_oop(oop o) {
  35     // the sentinel for deleted handles isn't visible
  36     if (o == JNIHandles::deleted_handle()) {
  37       return false;
  38     }
  39 
  40     // ignore KlassKlass
  41     if (o->is_klass()) {
  42       return false;
  43     }
  44 
  45     // instance
  46     if (o->is_instance()) {
  47       // instance objects are visible
  48       if (o->klass() != SystemDictionary::Class_klass()) {
  49         return true;
  50       }
  51       if (java_lang_Class::is_primitive(o)) {
  52         return true;
  53       }
  54       // java.lang.Classes are visible
  55       o = java_lang_Class::as_klassOop(o);
  56       if (o->is_klass()) {
  57         // if it's a class for an object, an object array, or
  58         // primitive (type) array then it's visible.
  59         klassOop klass = (klassOop)o;
  60         if (Klass::cast(klass)->oop_is_instance()) {
  61           return true;
  62         }
  63         if (Klass::cast(klass)->oop_is_objArray()) {
  64           return true;
  65         }
  66         if (Klass::cast(klass)->oop_is_typeArray()) {
  67           return true;
  68         }
  69       }
  70       return false;
  71     }
  72     // object arrays are visible if they aren't system object arrays
  73     if (o->is_objArray()) {
  74       objArrayOop array = (objArrayOop)o;
  75       if (array->klass() != Universe::systemObjArrayKlassObj()) {
  76         return true;
  77       } else {
  78         return false;
  79       }
  80     }
  81     // type arrays are visible
  82     if (o->is_typeArray()) {
  83       return true;
  84     }
  85     // everything else (methodOops, ...) aren't visible
  86     return false;
  87   };   // end of visible_oop()
  88 
  89 };