aoqi@0: /*
aoqi@0:  * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
aoqi@0: #define SHARE_VM_MEMORY_MODREFBARRIERSET_HPP
aoqi@0: 
aoqi@0: #include "memory/barrierSet.hpp"
aoqi@0: 
aoqi@0: // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
aoqi@0: // enumerate ref fields that have been modified (since the last
aoqi@0: // enumeration), using a card table.
aoqi@0: 
aoqi@0: class OopClosure;
aoqi@0: class Generation;
aoqi@0: 
aoqi@0: class ModRefBarrierSet: public BarrierSet {
aoqi@0: public:
aoqi@0: 
aoqi@0:   ModRefBarrierSet() { _kind = BarrierSet::ModRef; }
aoqi@0: 
aoqi@0:   bool is_a(BarrierSet::Name bsn) {
aoqi@0:     return bsn == BarrierSet::ModRef;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Barriers only on ref writes.
aoqi@0:   bool has_read_ref_barrier() { return false; }
aoqi@0:   bool has_read_prim_barrier() { return false; }
aoqi@0:   bool has_write_ref_barrier() { return true; }
aoqi@0:   bool has_write_prim_barrier() { return false; }
aoqi@0: 
aoqi@0:   bool read_ref_needs_barrier(void* field) { return false; }
aoqi@0:   bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
aoqi@0:   bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
aoqi@0:                                 juint val1, juint val2) { return false; }
aoqi@0: 
aoqi@0:   void write_prim_field(oop obj, size_t offset, size_t bytes,
aoqi@0:                         juint val1, juint val2) {}
aoqi@0: 
aoqi@0:   void read_ref_field(void* field) {}
aoqi@0:   void read_prim_field(HeapWord* field, size_t bytes) {}
aoqi@0: protected:
aoqi@0:   virtual void write_ref_field_work(void* field, oop new_val, bool release = false) = 0;
aoqi@0: public:
aoqi@0:   void write_prim_field(HeapWord* field, size_t bytes,
aoqi@0:                         juint val1, juint val2) {}
aoqi@0: 
aoqi@0:   bool has_read_ref_array_opt() { return false; }
aoqi@0:   bool has_read_prim_array_opt() { return false; }
aoqi@0:   bool has_write_prim_array_opt() { return false; }
aoqi@0: 
aoqi@0:   bool has_read_region_opt() { return false; }
aoqi@0: 
aoqi@0: 
aoqi@0:   // These operations should assert false unless the correponding operation
aoqi@0:   // above returns true.
aoqi@0:   void read_ref_array(MemRegion mr) {
aoqi@0:     assert(false, "can't call");
aoqi@0:   }
aoqi@0:   void read_prim_array(MemRegion mr) {
aoqi@0:     assert(false, "can't call");
aoqi@0:   }
aoqi@0:   void write_prim_array(MemRegion mr) {
aoqi@0:     assert(false, "can't call");
aoqi@0:   }
aoqi@0:   void read_region(MemRegion mr) {
aoqi@0:     assert(false, "can't call");
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Causes all refs in "mr" to be assumed to be modified.  If "whole_heap"
aoqi@0:   // is true, the caller asserts that the entire heap is being invalidated,
aoqi@0:   // which may admit an optimized implementation for some barriers.
aoqi@0:   virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0;
aoqi@0: 
aoqi@0:   // The caller guarantees that "mr" contains no references.  (Perhaps it's
aoqi@0:   // objects have been moved elsewhere.)
aoqi@0:   virtual void clear(MemRegion mr) = 0;
aoqi@0: 
aoqi@0:   // Pass along the argument to the superclass.
aoqi@0:   ModRefBarrierSet(int max_covered_regions) :
aoqi@0:     BarrierSet(max_covered_regions) {}
aoqi@0: };
aoqi@0: 
aoqi@0: #endif // SHARE_VM_MEMORY_MODREFBARRIERSET_HPP