1 /*
   2  * Copyright (c) 2014, 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_GC_SHARED_GCID_HPP
  26 #define SHARE_VM_GC_SHARED_GCID_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 class GCId : public AllStatic {
  31   friend class GCIdMark;
  32   friend class GCIdMarkAndRestore;
  33   static uint _next_id;
  34   static const uint UNDEFINED = (uint)-1;
  35   static const uint create();
  36 
  37  public:
  38   // Returns the currently active GC id. Asserts that there is an active GC id.
  39   static const uint current();
  40   // Same as current() but can return undefined() if no GC id is currently active
  41   static const uint current_raw();
  42   static const uint undefined() { return UNDEFINED; }
  43   static size_t print_prefix(char* buf, size_t len);
  44 };
  45 
  46 class GCIdMark : public StackObj {
  47   uint _gc_id;
  48  public:
  49   GCIdMark();
  50   GCIdMark(uint gc_id);
  51   ~GCIdMark();
  52 };
  53 
  54 class GCIdMarkAndRestore : public StackObj {
  55   uint _gc_id;
  56   uint _previous_gc_id;
  57  public:
  58   GCIdMarkAndRestore();
  59   GCIdMarkAndRestore(uint gc_id);
  60   ~GCIdMarkAndRestore();
  61 };
  62 
  63 #endif // SHARE_VM_GC_SHARED_GCID_HPP