1 /*
   2  * Copyright (c) 2003, 2015, 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     // instance
  47     if (o->is_instance()) {
  48       // instance objects are visible
  49       if (o->klass() != SystemDictionary::Class_klass()) {
  50         return true;
  51       }
  52       if (java_lang_Class::is_primitive(o)) {
  53         return true;
  54       }
  55       // java.lang.Classes are visible
  56       Klass* k = java_lang_Class::as_Klass(o);
  57       if (k->is_klass()) {
  58         // if it's a class for an object, an object array, or
  59         // primitive (type) array then it's visible.
  60         if (k->is_instance_klass()) {
  61           return true;
  62         }
  63         if (k->is_objArray_klass()) {
  64           return true;
  65         }
  66         if (k->is_typeArray_klass()) {
  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         return true;
  75     }
  76     // type arrays are visible
  77     if (o->is_typeArray()) {
  78       return true;
  79     }
  80     // everything else (Method*s, ...) aren't visible
  81     return false;
  82   };   // end of visible_oop()
  83 
  84 };
  85 
  86 #endif // SHARE_VM_SERVICES_SERVICEUTIL_HPP