1 /*
   2  * Copyright (c) 2011, 2012, 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_OOPS_METADATA_HPP
  26 #define SHARE_VM_OOPS_METADATA_HPP
  27 
  28 #include "utilities/exceptions.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 #include "utilities/ostream.hpp"
  31 
  32 // This is the base class for an internal Class related metadata
  33 class Metadata : public MetaspaceObj {
  34   // Debugging hook to check that the metadata has not been deleted.
  35   NOT_PRODUCT(int _valid;)
  36  public:
  37   NOT_PRODUCT(Metadata()     { _valid = 0; })
  38   NOT_PRODUCT(bool is_valid() const volatile { return _valid == 0; })
  39 
  40   int identity_hash()                { return (int)(uintptr_t)this; }
  41 
  42   // Rehashing support for tables containing pointers to this
  43   unsigned int new_hash(jint seed)   { ShouldNotReachHere();  return 0; }
  44 
  45   virtual bool is_klass()              const volatile { return false; }
  46   virtual bool is_method()             const volatile { return false; }
  47   virtual bool is_methodData()         const volatile { return false; }
  48   virtual bool is_constantPool()       const volatile { return false; }
  49 
  50   virtual const char* internal_name()  const = 0;
  51 
  52   void print()       const { print_on(tty); }
  53   void print_value() const { print_value_on(tty); }
  54 
  55   void print_maybe_null() const { print_on_maybe_null(tty); }
  56   void print_on_maybe_null(outputStream* st) const {
  57     if (this == NULL)
  58       st->print("NULL");
  59     else
  60       print_on(tty);
  61   }
  62   void print_value_on_maybe_null(outputStream* st) const {
  63     if (this == NULL)
  64       st->print("NULL");
  65     else
  66       print_value_on(tty);
  67   }
  68 
  69   virtual void print_on(outputStream* st) const;       // First level print
  70   virtual void print_value_on(outputStream* st) const = 0; // Second level print
  71 
  72   char* print_value_string() const;
  73 
  74   // Used to keep metadata alive during class redefinition
  75   // Can't assert because is called for delete functions (as an assert)
  76   virtual bool on_stack() const { return false; }
  77   virtual void set_on_stack(const bool value);
  78 
  79   // Set on_stack bit, so that the metadata is not cleared
  80   // during class redefinition.  This is a virtual call because only methods
  81   // and constant pools need to be set, but someday instanceKlasses might also.
  82   static void mark_on_stack(Metadata* m) { m->set_on_stack(true); }
  83 };
  84 
  85 #endif // SHARE_VM_OOPS_METADATA_HPP