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