1 /*
   2  * Copyright (c) 2003, 2010, 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 #ifndef SHARE_VM_SERVICES_SERVICEUTIL_HPP
  26 #define SHARE_VM_SERVICES_SERVICEUTIL_HPP
  27 
  28 #include "classfile/systemDictionary.hpp"
  29 #include "oops/objArrayOop.hpp"
  30 
  31 //
  32 // Serviceability utility functions.
  33 // (Shared by MM and JVMTI).
  34 //
  35 class ServiceUtil : public AllStatic {
  36  public:
  37 
  38   // Return true if oop represents an object that is "visible"
  39   // to the java world.
  40   static inline bool visible_oop(oop o) {
  41     // the sentinel for deleted handles isn't visible
  42     if (o == JNIHandles::deleted_handle()) {
  43       return false;
  44     }
  45 
  46     // ignore KlassKlass
  47     if (o->is_klass()) {
  48       return false;
  49     }
  50 
  51     // instance
  52     if (o->is_instance()) {
  53       // instance objects are visible
  54       if (o->klass() != SystemDictionary::Class_klass()) {
  55         return true;
  56       }
  57       if (java_lang_Class::is_primitive(o)) {
  58         return true;
  59       }
  60       // java.lang.Classes are visible
  61       o = java_lang_Class::as_klassOop(o);
  62       if (o->is_klass()) {
  63         // if it's a class for an object, an object array, or
  64         // primitive (type) array then it's visible.
  65         klassOop klass = (klassOop)o;
  66         if (Klass::cast(klass)->oop_is_instance()) {
  67           return true;
  68         }
  69         if (Klass::cast(klass)->oop_is_objArray()) {
  70           return true;
  71         }
  72         if (Klass::cast(klass)->oop_is_typeArray()) {
  73           return true;
  74         }
  75       }
  76       return false;
  77     }
  78     // object arrays are visible if they aren't system object arrays
  79     if (o->is_objArray()) {
  80       objArrayOop array = (objArrayOop)o;
  81       if (array->klass() != Universe::systemObjArrayKlassObj()) {
  82         return true;
  83       } else {
  84         return false;
  85       }
  86     }
  87     // type arrays are visible
  88     if (o->is_typeArray()) {
  89       return true;
  90     }
  91     // everything else (methodOops, ...) aren't visible
  92     return false;
  93   };   // end of visible_oop()
  94 
  95 };
  96 
  97 #endif // SHARE_VM_SERVICES_SERVICEUTIL_HPP