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_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 ModRefBarrierSet()40 ModRefBarrierSet() { _kind = BarrierSet::ModRef; } 41 is_a(BarrierSet::Name bsn)42 bool is_a(BarrierSet::Name bsn) { 43 return bsn == BarrierSet::ModRef; 44 } 45 46 // Barriers only on ref writes. has_read_ref_barrier()47 bool has_read_ref_barrier() { return false; } has_read_prim_barrier()48 bool has_read_prim_barrier() { return false; } has_write_ref_barrier()49 bool has_write_ref_barrier() { return true; } has_write_prim_barrier()50 bool has_write_prim_barrier() { return false; } 51 read_ref_needs_barrier(void * field)52 bool read_ref_needs_barrier(void* field) { return false; } read_prim_needs_barrier(HeapWord * field,size_t bytes)53 bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; } write_prim_needs_barrier(HeapWord * field,size_t bytes,juint val1,juint val2)54 bool write_prim_needs_barrier(HeapWord* field, size_t bytes, 55 juint val1, juint val2) { return false; } 56 write_prim_field(oop obj,size_t offset,size_t bytes,juint val1,juint val2)57 void write_prim_field(oop obj, size_t offset, size_t bytes, 58 juint val1, juint val2) {} 59 read_ref_field(void * field)60 void read_ref_field(void* field) {} read_prim_field(HeapWord * field,size_t bytes)61 void read_prim_field(HeapWord* field, size_t bytes) {} 62 protected: 63 virtual void write_ref_field_work(void* field, oop new_val, bool release = false) = 0; 64 public: write_prim_field(HeapWord * field,size_t bytes,juint val1,juint val2)65 void write_prim_field(HeapWord* field, size_t bytes, 66 juint val1, juint val2) {} 67 has_read_ref_array_opt()68 bool has_read_ref_array_opt() { return false; } has_read_prim_array_opt()69 bool has_read_prim_array_opt() { return false; } has_write_prim_array_opt()70 bool has_write_prim_array_opt() { return false; } 71 has_read_region_opt()72 bool has_read_region_opt() { return false; } 73 74 75 // These operations should assert false unless the correponding operation 76 // above returns true. read_ref_array(MemRegion mr)77 void read_ref_array(MemRegion mr) { 78 assert(false, "can't call"); 79 } read_prim_array(MemRegion mr)80 void read_prim_array(MemRegion mr) { 81 assert(false, "can't call"); 82 } write_prim_array(MemRegion mr)83 void write_prim_array(MemRegion mr) { 84 assert(false, "can't call"); 85 } read_region(MemRegion mr)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 // Pass along the argument to the superclass. ModRefBarrierSet(int max_covered_regions)100 ModRefBarrierSet(int max_covered_regions) : 101 BarrierSet(max_covered_regions) {} 102 }; 103 104 #endif // SHARE_VM_MEMORY_MODREFBARRIERSET_HPP 105