1 /*
   2  * Copyright (c) 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 #ifndef SHARE_VM_GC_G1_G1CODECACHEREMSET_INTERNAL_HPP
  25 #define SHARE_VM_GC_G1_G1CODECACHEREMSET_INTERNAL_HPP
  26 
  27 class CodeRootSetTable : public Hashtable<nmethod*, mtGC> {
  28   friend class G1CodeRootSetTest;
  29   typedef HashtableEntry<nmethod*, mtGC> Entry;
  30 
  31   static CodeRootSetTable* volatile _purge_list;
  32 
  33   CodeRootSetTable* _purge_next;
  34 
  35   unsigned int compute_hash(nmethod* nm) {
  36     uintptr_t hash = (uintptr_t)nm;
  37     return hash ^ (hash >> 7); // code heap blocks are 128byte aligned
  38   }
  39 
  40   void remove_entry(Entry* e, Entry* previous);
  41   Entry* new_entry(nmethod* nm);
  42 
  43  public:
  44   CodeRootSetTable(int size) : Hashtable<nmethod*, mtGC>(size, sizeof(Entry)), _purge_next(NULL) {}
  45   ~CodeRootSetTable();
  46 
  47   // Needs to be protected by locks
  48   bool add(nmethod* nm);
  49   bool remove(nmethod* nm);
  50 
  51   // Can be called without locking
  52   bool contains(nmethod* nm);
  53 
  54   int entry_size() const { return BasicHashtable<mtGC>::entry_size(); }
  55 
  56   void copy_to(CodeRootSetTable* new_table);
  57   void nmethods_do(CodeBlobClosure* blk);
  58 
  59   template<typename CB>
  60   int remove_if(CB& should_remove);
  61 
  62   static void purge_list_append(CodeRootSetTable* tbl);
  63   static void purge();
  64 
  65   static size_t static_mem_size() {
  66     return sizeof(_purge_list);
  67   }
  68 
  69   size_t mem_size();
  70 };
  71 
  72 #endif /* SHARE_VM_GC_G1_G1CODECACHEREMSET_INTERNAL_HPP */