1 /*
   2  * Copyright (c) 2000, 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_MEMORY_BARRIERSET_HPP
  26 #define SHARE_VM_MEMORY_BARRIERSET_HPP
  27 
  28 #include "memory/memRegion.hpp"
  29 #include "oops/oopsHierarchy.hpp"
  30 
  31 // This class provides the interface between a barrier implementation and
  32 // the rest of the system.
  33 
  34 class BarrierSet: public CHeapObj<mtGC> {
  35   friend class VMStructs;
  36 public:
  37   enum Name {
  38     ModRef,
  39     CardTableModRef,
  40     CardTableExtension,
  41     G1SATBCT,
  42     G1SATBCTLogging,
  43     Other,
  44     Uninit
  45   };
  46 
  47   enum Flags {
  48     None                = 0,
  49     TargetUninitialized = 1
  50   };
  51 protected:
  52   // Some barrier sets create tables whose elements correspond to parts of
  53   // the heap; the CardTableModRefBS is an example.  Such barrier sets will
  54   // normally reserve space for such tables, and commit parts of the table
  55   // "covering" parts of the heap that are committed. At most one covered
  56   // region per generation is needed.
  57   static const int _max_covered_regions = 2;
  58   Name _kind;
  59 



  60 public:
  61 
  62   BarrierSet() { _kind = Uninit; }
  63   // To get around prohibition on RTTI.
  64   BarrierSet::Name kind() { return _kind; }
  65   virtual bool is_a(BarrierSet::Name bsn) = 0;
  66 
  67   // These operations indicate what kind of barriers the BarrierSet has.
  68   virtual bool has_read_ref_barrier() = 0;
  69   virtual bool has_read_prim_barrier() = 0;
  70   virtual bool has_write_ref_barrier() = 0;
  71   virtual bool has_write_ref_pre_barrier() = 0;
  72   virtual bool has_write_prim_barrier() = 0;
  73 
  74   // These functions indicate whether a particular access of the given
  75   // kinds requires a barrier.
  76   virtual bool read_ref_needs_barrier(void* field) = 0;
  77   virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0;
  78   virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
  79                                         juint val1, juint val2) = 0;
  80 
  81   // The first four operations provide a direct implementation of the
  82   // barrier set.  An interpreter loop, for example, could call these

   1 /*
   2  * Copyright (c) 2000, 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_MEMORY_BARRIERSET_HPP
  26 #define SHARE_VM_MEMORY_BARRIERSET_HPP
  27 
  28 #include "memory/memRegion.hpp"
  29 #include "oops/oopsHierarchy.hpp"
  30 
  31 // This class provides the interface between a barrier implementation and
  32 // the rest of the system.
  33 
  34 class BarrierSet: public CHeapObj<mtGC> {
  35   friend class VMStructs;
  36 public:
  37   enum Name {
  38     ModRef,
  39     CardTableModRef,
  40     CardTableExtension,
  41     G1SATBCT,
  42     G1SATBCTLogging,
  43     Other

  44   };
  45 
  46   enum Flags {
  47     None                = 0,
  48     TargetUninitialized = 1
  49   };
  50 protected:
  51   // Some barrier sets create tables whose elements correspond to parts of
  52   // the heap; the CardTableModRefBS is an example.  Such barrier sets will
  53   // normally reserve space for such tables, and commit parts of the table
  54   // "covering" parts of the heap that are committed. At most one covered
  55   // region per generation is needed.
  56   static const int _max_covered_regions = 2;
  57   Name _kind;
  58 
  59   BarrierSet(Name kind) : _kind(kind) { }
  60   ~BarrierSet() { }
  61 
  62 public:
  63 

  64   // To get around prohibition on RTTI.
  65   BarrierSet::Name kind() { return _kind; }
  66   virtual bool is_a(BarrierSet::Name bsn) = 0;
  67 
  68   // These operations indicate what kind of barriers the BarrierSet has.
  69   virtual bool has_read_ref_barrier() = 0;
  70   virtual bool has_read_prim_barrier() = 0;
  71   virtual bool has_write_ref_barrier() = 0;
  72   virtual bool has_write_ref_pre_barrier() = 0;
  73   virtual bool has_write_prim_barrier() = 0;
  74 
  75   // These functions indicate whether a particular access of the given
  76   // kinds requires a barrier.
  77   virtual bool read_ref_needs_barrier(void* field) = 0;
  78   virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0;
  79   virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
  80                                         juint val1, juint val2) = 0;
  81 
  82   // The first four operations provide a direct implementation of the
  83   // barrier set.  An interpreter loop, for example, could call these