1 /*
2 * Copyright (c) 2000, 2026, 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_GC_SHARED_CARDTABLEBARRIERSET_INLINE_HPP
26 #define SHARE_GC_SHARED_CARDTABLEBARRIERSET_INLINE_HPP
27
28 #include "gc/shared/cardTableBarrierSet.hpp"
29
30 #include "gc/shared/barrierSet.hpp"
31 #include "gc/shared/cardTable.hpp"
32 #include "oops/compressedOops.inline.hpp"
33 #include "oops/inlineKlass.inline.hpp"
34 #include "oops/layoutKind.hpp"
35 #include "oops/objArrayOop.hpp"
36 #include "oops/oop.hpp"
37 #include "utilities/debug.hpp"
38
39 template <DecoratorSet decorators, typename T>
40 inline void CardTableBarrierSet::write_ref_field_post(T* field) {
41 volatile CardValue* byte = card_table()->byte_for(field);
42 *byte = CardTable::dirty_card_val();
43 }
44
45 class Klass;
46
47 // count is number of array elements being written
48 void CardTableBarrierSet::write_ref_array(HeapWord* start, size_t count) {
49 HeapWord* end = (HeapWord*)((char*)start + (count*heapOopSize));
50 // In the case of compressed oops, start and end may potentially be misaligned;
51 // so we need to conservatively align the first downward (this is not
52 // strictly necessary for current uses, but a case of good hygiene and,
53 // if you will, aesthetics) and the second upward (this is essential for
54 // current uses) to a HeapWord boundary, so we mark all cards overlapping
55 // this write. If this evolves in the future to calling a
56 // logging barrier of narrow oop granularity, like the pre-barrier for G1
57 // (mentioned here merely by way of example), we will need to change this
58 // interface, so it is "exactly precise" (if i may be allowed the adverbial
59 // redundancy for emphasis) and does not include narrow oop slots not
60 // included in the original write interval.
61 HeapWord* aligned_start = align_down(start, HeapWordSize);
62 HeapWord* aligned_end = align_up (end, HeapWordSize);
63 // If compressed oops were not being used, these should already be aligned
64 assert(UseCompressedOops || (aligned_start == start && aligned_end == end),
65 "Expected heap word alignment of start and end");
66 write_region(MemRegion(aligned_start, aligned_end));
67 }
68
69 template <DecoratorSet decorators, typename BarrierSetT>
70 template <typename T>
71 inline void CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
72 oop_store_in_heap(T* addr, oop value) {
73 BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
74 bs->template write_ref_field_pre<decorators>(addr);
75 Raw::oop_store(addr, value);
76 bs->template write_ref_field_post<decorators>(addr);
77 }
78
79 template <DecoratorSet decorators, typename BarrierSetT>
80 template <typename T>
81 inline oop CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
82 oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
83 BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
84 bs->template write_ref_field_pre<decorators>(addr);
85 oop result = Raw::oop_atomic_cmpxchg(addr, compare_value, new_value);
86 if (result == compare_value) {
87 bs->template write_ref_field_post<decorators>(addr);
88 }
89 return result;
90 }
91
92 template <DecoratorSet decorators, typename BarrierSetT>
93 template <typename T>
94 inline oop CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
95 oop_atomic_xchg_in_heap(T* addr, oop new_value) {
96 BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
97 bs->template write_ref_field_pre<decorators>(addr);
98 oop result = Raw::oop_atomic_xchg(addr, new_value);
99 bs->template write_ref_field_post<decorators>(addr);
100 return result;
101 }
102
103 template <DecoratorSet decorators, typename BarrierSetT>
104 template <typename T>
105 inline void CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
106 oop_arraycopy_partial_barrier(BarrierSetT *bs, T* dst_raw, T* p) {
107 const size_t pd = pointer_delta(p, dst_raw, (size_t)heapOopSize);
108 // pointer delta is scaled to number of elements (length field in
109 // objArrayOop) which we assume is 32 bit.
110 assert(pd == (size_t)(int)pd, "length field overflow");
111 bs->write_ref_array((HeapWord*)dst_raw, pd);
112 }
113
114 template <DecoratorSet decorators, typename BarrierSetT>
115 template <typename T>
116 inline OopCopyResult CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
117 oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
118 arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
119 size_t length) {
120 BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
121
122 src_raw = arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw);
123 dst_raw = arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw);
124
125 if ((!HasDecorator<decorators, ARRAYCOPY_CHECKCAST>::value) &&
126 (!HasDecorator<decorators, ARRAYCOPY_NOTNULL>::value)) {
127 // Optimized covariant case
128 bs->write_ref_array_pre(dst_raw, length,
129 HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value);
130 Raw::oop_arraycopy(nullptr, 0, src_raw, nullptr, 0, dst_raw, length);
131 bs->write_ref_array((HeapWord*)dst_raw, length);
132 } else {
133 assert(dst_obj != nullptr, "better have an actual oop");
134 Klass* bound = objArrayOop(dst_obj)->element_klass();
135 T* from = const_cast<T*>(src_raw);
136 T* end = from + length;
137 for (T* p = dst_raw; from < end; from++, p++) {
138 T element = *from;
139 // Apply any required checks
140 if (HasDecorator<decorators, ARRAYCOPY_NOTNULL>::value && CompressedOops::is_null(element)) {
141 oop_arraycopy_partial_barrier(bs, dst_raw, p);
142 return OopCopyResult::failed_check_null;
143 }
144 if (HasDecorator<decorators, ARRAYCOPY_CHECKCAST>::value &&
145 (!oopDesc::is_instanceof_or_null(CompressedOops::decode(element), bound))) {
146 oop_arraycopy_partial_barrier(bs, dst_raw, p);
147 return OopCopyResult::failed_check_class_cast;
148 }
149 // write
150 bs->template write_ref_field_pre<decorators>(p);
151 *p = element;
152 }
153 bs->write_ref_array((HeapWord*)dst_raw, length);
154 }
155
156 return OopCopyResult::ok;
157 }
158
159 template <DecoratorSet decorators, typename BarrierSetT>
160 inline void CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
161 clone_in_heap(oop src, oop dst, size_t size) {
162 Raw::clone(src, dst, size);
163 BarrierSetT *bs = barrier_set_cast<BarrierSetT>(barrier_set());
164 bs->write_region(MemRegion((HeapWord*)(void*)dst, size));
165 }
166
167 template <DecoratorSet decorators, typename BarrierSetT>
168 inline void CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
169 value_copy_in_heap(const ValuePayload& src, const ValuePayload& dst) {
170 precond(src.klass() == dst.klass());
171
172 const InlineKlass* md = src.klass();
173 if (!md->contains_oops()) {
174 // If we do not have oops in the flat array, we can just do a raw copy.
175 Raw::value_copy(src, dst);
176 } else {
177 BarrierSetT* bs = barrier_set_cast<BarrierSetT>(BarrierSet::barrier_set());
178 // addr() points at the payload start, the oop map offset are relative to
179 // the object header, adjust address to account for this discrepancy.
180 const address oop_map_adjusted_dst_addr = dst.addr() - md->payload_offset();
181 typedef typename ValueOopType<decorators>::type OopType;
182
183 // Pre-barriers...
184 OopMapBlock* map = md->start_of_nonstatic_oop_maps();
185 OopMapBlock* const end = map + md->nonstatic_oop_map_count();
186 bool is_uninitialized = HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value;
187 while (map != end) {
188 address doop_address = oop_map_adjusted_dst_addr + map->offset();
189 // The pre-barrier only impacts G1, which will emit a barrier if the destination is
190 // initialized. Note that we should not emit a barrier if the destination is uninitialized,
191 // as doing so will fill the SATB queue with garbage data.
192 bs->write_ref_array_pre((OopType*) doop_address, map->count(), is_uninitialized);
193 map++;
194 }
195
196 Raw::value_copy(src, dst);
197
198 // Post-barriers...
199 map = md->start_of_nonstatic_oop_maps();
200 while (map != end) {
201 address doop_address = oop_map_adjusted_dst_addr + map->offset();
202 // The post-barrier needs to be called for initialized and uninitialized destinations.
203 bs->write_ref_array((HeapWord*) doop_address, map->count());
204 map++;
205 }
206 }
207 }
208
209 template <DecoratorSet decorators, typename BarrierSetT>
210 inline void CardTableBarrierSet::AccessBarrier<decorators, BarrierSetT>::
211 value_store_null_in_heap(const ValuePayload& dst) {
212 const InlineKlass* md = dst.klass();
213 if (!md->contains_oops()) {
214 // If we do not have oops in the flat array, we can just do a raw clear.
215 Raw::value_store_null(dst);
216 } else {
217 BarrierSetT* bs = barrier_set_cast<BarrierSetT>(BarrierSet::barrier_set());
218 // addr() points at the payload start, the oop map offset are relative to
219 // the object header, adjust address to account for this discrepancy.
220 const address oop_map_adjusted_dst_addr = dst.addr() - md->payload_offset();
221 typedef typename ValueOopType<decorators>::type OopType;
222
223 // Pre-barriers...
224 OopMapBlock* map = md->start_of_nonstatic_oop_maps();
225 OopMapBlock* const end = map + md->nonstatic_oop_map_count();
226 bool is_uninitialized = HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value;
227 while (map != end) {
228 address doop_address = oop_map_adjusted_dst_addr + map->offset();
229 // The pre-barrier only impacts G1, which will emit a barrier if the destination is
230 // initialized. Note that we should not emit a barrier if the destination is uninitialized,
231 // as doing so will fill the SATB queue with garbage data.
232 bs->write_ref_array_pre((OopType*) doop_address, map->count(), is_uninitialized);
233 map++;
234 }
235
236 Raw::value_store_null(dst);
237
238 // Post-barriers...
239 map = md->start_of_nonstatic_oop_maps();
240 while (map != end) {
241 address doop_address = oop_map_adjusted_dst_addr + map->offset();
242 // The post-barrier needs to be called for initialized and uninitialized destinations.
243 bs->write_ref_array((HeapWord*) doop_address, map->count());
244 map++;
245 }
246 }
247 }
248
249 #endif // SHARE_GC_SHARED_CARDTABLEBARRIERSET_INLINE_HPP