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_MODREFBARRIERSET_HPP
  26 #define SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
  27 
  28 #include "memory/barrierSet.hpp"
  29 
  30 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
  31 // enumerate ref fields that have been modified (since the last
  32 // enumeration), using a card table.
  33 
  34 class OopClosure;
  35 class Generation;
  36 
  37 class ModRefBarrierSet: public BarrierSet {
  38 public:
  39 
  40   // Barriers only on ref writes.
  41   bool has_read_ref_barrier() { return false; }
  42   bool has_read_prim_barrier() { return false; }
  43   bool has_write_ref_barrier() { return true; }
  44   bool has_write_prim_barrier() { return false; }
  45 
  46   bool read_ref_needs_barrier(void* field) { return false; }
  47   bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
  48   bool write_prim_needs_barrier(HeapWord* field, size_t bytes,

  85   }
  86   void read_region(MemRegion mr) {
  87     assert(false, "can't call");
  88   }
  89 
  90   // Causes all refs in "mr" to be assumed to be modified.  If "whole_heap"
  91   // is true, the caller asserts that the entire heap is being invalidated,
  92   // which may admit an optimized implementation for some barriers.
  93   virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0;
  94 
  95   // The caller guarantees that "mr" contains no references.  (Perhaps it's
  96   // objects have been moved elsewhere.)
  97   virtual void clear(MemRegion mr) = 0;
  98 };
  99 
 100 template<>
 101 struct BarrierSet::GetName<ModRefBarrierSet> {
 102   static const BarrierSet::Name value = BarrierSet::ModRef;
 103 };
 104 
 105 #endif // SHARE_VM_MEMORY_MODREFBARRIERSET_HPP

   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_MODREFBARRIERSET_HPP
  26 #define SHARE_VM_GC_SHARED_MODREFBARRIERSET_HPP
  27 
  28 #include "gc/shared/barrierSet.hpp"
  29 
  30 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
  31 // enumerate ref fields that have been modified (since the last
  32 // enumeration), using a card table.
  33 
  34 class OopClosure;
  35 class Generation;
  36 
  37 class ModRefBarrierSet: public BarrierSet {
  38 public:
  39 
  40   // Barriers only on ref writes.
  41   bool has_read_ref_barrier() { return false; }
  42   bool has_read_prim_barrier() { return false; }
  43   bool has_write_ref_barrier() { return true; }
  44   bool has_write_prim_barrier() { return false; }
  45 
  46   bool read_ref_needs_barrier(void* field) { return false; }
  47   bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
  48   bool write_prim_needs_barrier(HeapWord* field, size_t bytes,

  85   }
  86   void read_region(MemRegion mr) {
  87     assert(false, "can't call");
  88   }
  89 
  90   // Causes all refs in "mr" to be assumed to be modified.  If "whole_heap"
  91   // is true, the caller asserts that the entire heap is being invalidated,
  92   // which may admit an optimized implementation for some barriers.
  93   virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0;
  94 
  95   // The caller guarantees that "mr" contains no references.  (Perhaps it's
  96   // objects have been moved elsewhere.)
  97   virtual void clear(MemRegion mr) = 0;
  98 };
  99 
 100 template<>
 101 struct BarrierSet::GetName<ModRefBarrierSet> {
 102   static const BarrierSet::Name value = BarrierSet::ModRef;
 103 };
 104 
 105 #endif // SHARE_VM_GC_SHARED_MODREFBARRIERSET_HPP