1 /*
2 * Copyright (c) 2015, 2022, Red Hat, Inc. 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.
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23 */
24
25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
26 #define SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
27
28 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
29
30 #include "gc/shared/accessBarrierSupport.inline.hpp"
31 #include "gc/shenandoah/shenandoahAsserts.hpp"
32 #include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"
33 #include "gc/shenandoah/shenandoahEvacOOMHandler.inline.hpp"
34 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
35 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
36 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
37 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
38 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
39 #include "oops/oop.inline.hpp"
40
41 inline oop ShenandoahBarrierSet::resolve_forwarded_not_null(oop p) {
42 return ShenandoahForwarding::get_forwardee(p);
43 }
44
45 inline oop ShenandoahBarrierSet::resolve_forwarded(oop p) {
46 if (p != nullptr) {
47 return resolve_forwarded_not_null(p);
48 } else {
49 return p;
50 }
51 }
52
53 inline oop ShenandoahBarrierSet::resolve_forwarded_not_null_mutator(oop p) {
54 return ShenandoahForwarding::get_forwardee_mutator(p);
55 }
56
57 template <class T>
58 inline oop ShenandoahBarrierSet::load_reference_barrier_mutator(oop obj, T* load_addr) {
59 assert(ShenandoahLoadRefBarrier, "should be enabled");
60 shenandoah_assert_in_cset(load_addr, obj);
61
62 oop fwd = resolve_forwarded_not_null_mutator(obj);
63 if (obj == fwd) {
64 assert(_heap->is_evacuation_in_progress(),
65 "evac should be in progress");
66 Thread* const t = Thread::current();
67 ShenandoahEvacOOMScope scope(t);
68 fwd = _heap->evacuate_object(obj, t);
69 }
70
71 if (load_addr != nullptr && fwd != obj) {
72 // Since we are here and we know the load address, update the reference.
73 ShenandoahHeap::atomic_update_oop(fwd, load_addr, obj);
74 }
75
76 return fwd;
77 }
78
79 inline oop ShenandoahBarrierSet::load_reference_barrier(oop obj) {
80 if (!ShenandoahLoadRefBarrier) {
81 return obj;
82 }
83 if (_heap->has_forwarded_objects() &&
84 _heap->in_collection_set(obj)) { // Subsumes null-check
85 assert(obj != nullptr, "cset check must have subsumed null-check");
86 oop fwd = resolve_forwarded_not_null(obj);
87 if (obj == fwd && _heap->is_evacuation_in_progress()) {
88 Thread* t = Thread::current();
89 ShenandoahEvacOOMScope oom_evac_scope(t);
90 return _heap->evacuate_object(obj, t);
91 }
92 return fwd;
93 }
94 return obj;
95 }
96
97 template <class T>
98 inline oop ShenandoahBarrierSet::load_reference_barrier(DecoratorSet decorators, oop obj, T* load_addr) {
99 if (obj == nullptr) {
100 return nullptr;
101 }
102
103 // Prevent resurrection of unreachable phantom (i.e. weak-native) references.
104 if ((decorators & ON_PHANTOM_OOP_REF) != 0 &&
105 _heap->is_concurrent_weak_root_in_progress() &&
106 !_heap->marking_context()->is_marked(obj)) {
107 return nullptr;
108 }
109
110 // Prevent resurrection of unreachable weak references.
111 if ((decorators & ON_WEAK_OOP_REF) != 0 &&
112 _heap->is_concurrent_weak_root_in_progress() &&
113 !_heap->marking_context()->is_marked_strong(obj)) {
114 return nullptr;
115 }
116
117 // Prevent resurrection of unreachable objects that are visited during
118 // concurrent class-unloading.
119 if ((decorators & AS_NO_KEEPALIVE) != 0 &&
120 _heap->is_evacuation_in_progress() &&
121 !_heap->marking_context()->is_marked(obj)) {
122 return obj;
123 }
124
125 oop fwd = load_reference_barrier(obj);
126 if (load_addr != nullptr && fwd != obj) {
127 // Since we are here and we know the load address, update the reference.
128 ShenandoahHeap::atomic_update_oop(fwd, load_addr, obj);
129 }
130
131 return fwd;
132 }
133
134 inline void ShenandoahBarrierSet::enqueue(oop obj) {
135 assert(obj != nullptr, "checked by caller");
136 assert(_satb_mark_queue_set.is_active(), "only get here when SATB active");
137
138 // Filter marked objects before hitting the SATB queues. The same predicate would
139 // be used by SATBMQ::filter to eliminate already marked objects downstream, but
140 // filtering here helps to avoid wasteful SATB queueing work to begin with.
141 if (!_heap->requires_marking(obj)) return;
142
143 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(Thread::current());
144 _satb_mark_queue_set.enqueue_known_active(queue, obj);
145 }
146
147 template <DecoratorSet decorators, typename T>
148 inline void ShenandoahBarrierSet::satb_barrier(T *field) {
149 if (HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value ||
150 HasDecorator<decorators, AS_NO_KEEPALIVE>::value) {
151 return;
152 }
153 if (ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
154 T heap_oop = RawAccess<>::oop_load(field);
155 if (!CompressedOops::is_null(heap_oop)) {
156 enqueue(CompressedOops::decode(heap_oop));
157 }
158 }
159 }
160
161 inline void ShenandoahBarrierSet::satb_enqueue(oop value) {
162 if (value != nullptr && ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
163 enqueue(value);
164 }
165 }
166
167 inline void ShenandoahBarrierSet::keep_alive_if_weak(DecoratorSet decorators, oop value) {
168 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
169 const bool on_strong_oop_ref = (decorators & ON_STRONG_OOP_REF) != 0;
170 const bool peek = (decorators & AS_NO_KEEPALIVE) != 0;
171 if (!peek && !on_strong_oop_ref) {
172 satb_enqueue(value);
173 }
174 }
175
176 template <typename T>
177 inline oop ShenandoahBarrierSet::oop_load(DecoratorSet decorators, T* addr) {
178 oop value = RawAccess<>::oop_load(addr);
179 value = load_reference_barrier(decorators, value, addr);
180 keep_alive_if_weak(decorators, value);
181 return value;
182 }
183
184 template <typename T>
185 inline oop ShenandoahBarrierSet::oop_cmpxchg(DecoratorSet decorators, T* addr, oop compare_value, oop new_value) {
186 oop res;
187 oop expected = compare_value;
188 do {
189 compare_value = expected;
190 res = RawAccess<>::oop_atomic_cmpxchg(addr, compare_value, new_value);
191 expected = res;
192 } while ((compare_value != expected) && (resolve_forwarded(compare_value) == resolve_forwarded(expected)));
193
194 // Note: We don't need a keep-alive-barrier here. We already enqueue any loaded reference for SATB anyway,
195 // because it must be the previous value.
196 res = load_reference_barrier(decorators, res, static_cast<T*>(nullptr));
197 satb_enqueue(res);
198 return res;
199 }
200
201 template <typename T>
202 inline oop ShenandoahBarrierSet::oop_xchg(DecoratorSet decorators, T* addr, oop new_value) {
203 oop previous = RawAccess<>::oop_atomic_xchg(addr, new_value);
204 // Note: We don't need a keep-alive-barrier here. We already enqueue any loaded reference for SATB anyway,
205 // because it must be the previous value.
206 previous = load_reference_barrier<T>(decorators, previous, static_cast<T*>(nullptr));
207 satb_enqueue(previous);
208 return previous;
209 }
210
211 template <DecoratorSet decorators, typename BarrierSetT>
212 template <typename T>
213 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_not_in_heap(T* addr) {
214 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "must be absent");
215 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
216 return bs->oop_load(decorators, addr);
217 }
218
219 template <DecoratorSet decorators, typename BarrierSetT>
220 template <typename T>
221 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap(T* addr) {
222 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "must be absent");
223 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
224 return bs->oop_load(decorators, addr);
225 }
226
227 template <DecoratorSet decorators, typename BarrierSetT>
228 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap_at(oop base, ptrdiff_t offset) {
229 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
230 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
231 return bs->oop_load(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset));
232 }
233
234 template <DecoratorSet decorators, typename BarrierSetT>
235 template <typename T>
236 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_common(T* addr, oop value) {
237 shenandoah_assert_marked_if(nullptr, value, !CompressedOops::is_null(value) && ShenandoahHeap::heap()->is_evacuation_in_progress());
238 shenandoah_assert_not_in_cset_if(addr, value, value != nullptr && !ShenandoahHeap::heap()->cancelled_gc());
239 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
240 bs->satb_barrier<decorators>(addr);
241 Raw::oop_store(addr, value);
242 }
243
244 template <DecoratorSet decorators, typename BarrierSetT>
245 template <typename T>
246 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_not_in_heap(T* addr, oop value) {
247 oop_store_common(addr, value);
248 }
249
250 template <DecoratorSet decorators, typename BarrierSetT>
251 template <typename T>
252 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap(T* addr, oop value) {
253 shenandoah_assert_not_in_cset_loc_except(addr, ShenandoahHeap::heap()->cancelled_gc());
254 shenandoah_assert_not_forwarded_except (addr, value, value == nullptr || ShenandoahHeap::heap()->cancelled_gc() || !ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
255
256 oop_store_common(addr, value);
257 }
258
259 template <DecoratorSet decorators, typename BarrierSetT>
260 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
261 oop_store_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), value);
262 }
263
264 template <DecoratorSet decorators, typename BarrierSetT>
265 template <typename T>
266 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_not_in_heap(T* addr, oop compare_value, oop new_value) {
267 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
268 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
269 return bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
270 }
271
272 template <DecoratorSet decorators, typename BarrierSetT>
273 template <typename T>
274 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
275 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
276 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
277 return bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
278 }
279
280 template <DecoratorSet decorators, typename BarrierSetT>
281 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, oop compare_value, oop new_value) {
282 assert((decorators & AS_NO_KEEPALIVE) == 0, "must be absent");
283 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
284 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
285 return bs->oop_cmpxchg(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset), compare_value, new_value);
286 }
287
288 template <DecoratorSet decorators, typename BarrierSetT>
289 template <typename T>
290 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_not_in_heap(T* addr, oop new_value) {
291 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
292 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
293 return bs->oop_xchg(decorators, addr, new_value);
294 }
295
296 template <DecoratorSet decorators, typename BarrierSetT>
297 template <typename T>
298 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap(T* addr, oop new_value) {
299 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
300 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
301 return bs->oop_xchg(decorators, addr, new_value);
302 }
303
304 template <DecoratorSet decorators, typename BarrierSetT>
305 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, oop new_value) {
306 assert((decorators & AS_NO_KEEPALIVE) == 0, "must be absent");
307 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
308 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
309 return bs->oop_xchg(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset), new_value);
310 }
311
312 // Clone barrier support
313 template <DecoratorSet decorators, typename BarrierSetT>
314 void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::clone_in_heap(oop src, oop dst, size_t size) {
315 if (ShenandoahCloneBarrier) {
316 ShenandoahBarrierSet::barrier_set()->clone_barrier_runtime(src);
317 }
318 Raw::clone(src, dst, size);
319 }
320
321 template <DecoratorSet decorators, typename BarrierSetT>
322 template <typename T>
323 bool ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
324 arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
325 size_t length) {
326 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
327 bs->arraycopy_barrier(arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw),
328 arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw),
329 length);
330 return Raw::oop_arraycopy_in_heap(src_obj, src_offset_in_bytes, src_raw, dst_obj, dst_offset_in_bytes, dst_raw, length);
331 }
332
333 template <class T, bool HAS_FWD, bool EVAC, bool ENQUEUE>
334 void ShenandoahBarrierSet::arraycopy_work(T* src, size_t count) {
335 assert(HAS_FWD == _heap->has_forwarded_objects(), "Forwarded object status is sane");
336
337 Thread* thread = Thread::current();
338 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
339 ShenandoahMarkingContext* ctx = _heap->marking_context();
340 const ShenandoahCollectionSet* const cset = _heap->collection_set();
341 T* end = src + count;
342 for (T* elem_ptr = src; elem_ptr < end; elem_ptr++) {
343 T o = RawAccess<>::oop_load(elem_ptr);
344 if (!CompressedOops::is_null(o)) {
345 oop obj = CompressedOops::decode_not_null(o);
346 if (HAS_FWD && cset->is_in(obj)) {
347 oop fwd = resolve_forwarded_not_null(obj);
348 if (EVAC && obj == fwd) {
349 fwd = _heap->evacuate_object(obj, thread);
350 }
351 shenandoah_assert_forwarded_except(elem_ptr, obj, _heap->cancelled_gc());
352 ShenandoahHeap::atomic_update_oop(fwd, elem_ptr, o);
353 obj = fwd;
354 }
355 if (ENQUEUE && !ctx->is_marked_strong(obj)) {
356 _satb_mark_queue_set.enqueue_known_active(queue, obj);
357 }
358 }
359 }
360 }
361
362 template <class T>
363 void ShenandoahBarrierSet::arraycopy_barrier(T* src, T* dst, size_t count) {
364 if (count == 0) {
365 return;
366 }
367 int gc_state = _heap->gc_state();
368 if ((gc_state & ShenandoahHeap::MARKING) != 0) {
369 arraycopy_marking(src, dst, count);
370 } else if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
371 arraycopy_evacuation(src, count);
372 } else if ((gc_state & ShenandoahHeap::UPDATEREFS) != 0) {
373 arraycopy_update(src, count);
374 }
375 }
376
377 template <class T>
378 void ShenandoahBarrierSet::arraycopy_marking(T* src, T* dst, size_t count) {
379 assert(_heap->is_concurrent_mark_in_progress(), "only during marking");
380 T* array = ShenandoahSATBBarrier ? dst : src;
381 if (!_heap->marking_context()->allocated_after_mark_start(reinterpret_cast<HeapWord*>(array))) {
382 arraycopy_work<T, false, false, true>(array, count);
383 }
384 }
385
386 inline bool ShenandoahBarrierSet::need_bulk_update(HeapWord* ary) {
387 return ary < _heap->heap_region_containing(ary)->get_update_watermark();
388 }
389
390 template <class T>
391 void ShenandoahBarrierSet::arraycopy_evacuation(T* src, size_t count) {
392 assert(_heap->is_evacuation_in_progress(), "only during evacuation");
393 if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
394 ShenandoahEvacOOMScope oom_evac;
395 arraycopy_work<T, true, true, false>(src, count);
396 }
397 }
398
399 template <class T>
400 void ShenandoahBarrierSet::arraycopy_update(T* src, size_t count) {
401 assert(_heap->is_update_refs_in_progress(), "only during update-refs");
402 if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
403 arraycopy_work<T, true, false, false>(src, count);
404 }
405 }
406
407 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP