1 /*
   2  * Copyright (c) 2003, 2016, 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 #include "oops/oop.inline.hpp"
  31 
  32 //
  33 // Serviceability utility functions.
  34 // (Shared by MM and JVMTI).
  35 //
  36 class ServiceUtil : public AllStatic {
  37  public:
  38 
  39   // Return true if oop represents an object that is "visible"
  40   // to the java world.
  41   static inline bool visible_oop(oop o) {
  42     // the sentinel for deleted handles isn't visible
  43     if (o == JNIHandles::deleted_handle()) {
  44       return false;
  45     }
  46 
  47     // instance
  48     if (o->is_instance()) {
  49       // instance objects are visible
  50       if (o->klass() != SystemDictionary::Class_klass()) {
  51         return true;
  52       }
  53       if (java_lang_Class::is_primitive(o)) {
  54         return true;
  55       }
  56       // java.lang.Classes are visible
  57       Klass* k = java_lang_Class::as_Klass(o);
  58       if (k->is_klass()) {
  59         // if it's a class for an object, an object array, or
  60         // primitive (type) array then it's visible.
  61         if (k->is_instance_klass()) {
  62           return true;
  63         }
  64         if (k->is_objArray_klass()) {
  65           return true;
  66         }
  67         if (k->is_typeArray_klass()) {
  68           return true;
  69         }
  70       }
  71       return false;
  72     }
  73     // object arrays are visible if they aren't system object arrays
  74     if (o->is_objArray()) {
  75         return true;
  76     }
  77     // type arrays are visible
  78     if (o->is_typeArray()) {
  79       return true;
  80     }
  81     // everything else (Method*s, ...) aren't visible
  82     return false;
  83   };   // end of visible_oop()
  84 
  85 };
  86 
  87 #endif // SHARE_VM_SERVICES_SERVICEUTIL_HPP