1 /*
2 * Copyright (c) 2015, 2022, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
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24 */
25
26 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
27 #define SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
28
29 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
30
31 #include "gc/shared/accessBarrierSupport.inline.hpp"
32 #include "gc/shared/cardTable.hpp"
33 #include "gc/shenandoah/mode/shenandoahMode.hpp"
34 #include "gc/shenandoah/shenandoahAsserts.hpp"
35 #include "gc/shenandoah/shenandoahCardTable.hpp"
36 #include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"
37 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
38 #include "gc/shenandoah/shenandoahGeneration.hpp"
39 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
40 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
41 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
42 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
43 #include "memory/iterator.inline.hpp"
44 #include "oops/oop.inline.hpp"
45
46 template <DecoratorSet decorators, class T>
47 inline oop ShenandoahBarrierSet::load_reference_barrier_mutator(oop obj, T* load_addr) {
48 assert(ShenandoahLoadRefBarrier, "Should be enabled");
49
50 constexpr bool on_weak = HasDecorator<decorators, ON_WEAK_OOP_REF>::value;
51 constexpr bool on_phantom = HasDecorator<decorators, ON_PHANTOM_OOP_REF>::value;
52
53 // Handle nulls. Strong loads filtered nulls with cset checks.
54 // Weak/phantom loads need to check for nulls here.
55 if (on_weak || on_phantom) {
56 if (obj == nullptr) {
57 return nullptr;
58 }
59 } else {
60 assert(obj != nullptr, "Should have been filtered before");
61 }
62
63 // Prevent resurrection of unreachable phantom (i.e. weak-native) references.
64 if (on_phantom &&
65 _heap->is_concurrent_weak_root_in_progress() &&
66 _heap->is_in_active_generation(obj) &&
67 !_heap->marking_context()->is_marked(obj)) {
68 return nullptr;
69 }
70
71 // Prevent resurrection of unreachable weak references.
72 if (on_weak &&
73 _heap->is_concurrent_weak_root_in_progress() &&
74 _heap->is_in_active_generation(obj) &&
75 !_heap->marking_context()->is_marked_strong(obj)) {
76 return nullptr;
77 }
78
79 // Weak/phantom loads need additional cset check.
80 if (on_phantom || on_weak) {
81 if (!_heap->has_forwarded_objects() || !_heap->in_collection_set(obj)) {
82 return obj;
83 }
84 } else {
85 shenandoah_assert_in_cset(load_addr, obj);
86 }
87
88 oop fwd = ShenandoahForwarding::get_forwardee_mutator(obj);
89 if (obj == fwd) {
90 assert(_heap->is_evacuation_in_progress(), "evac should be in progress");
91 Thread* const t = Thread::current();
92 fwd = _heap->evacuate_object(obj, t);
93 }
94
95 if (load_addr != nullptr && fwd != obj) {
96 // Since we are here and we know the load address, update the reference.
97 ShenandoahHeap::atomic_update_oop(fwd, load_addr, obj);
98 }
99
100 return fwd;
101 }
102
103 inline oop ShenandoahBarrierSet::load_reference_barrier(oop obj) {
104 if (!ShenandoahLoadRefBarrier) {
105 return obj;
106 }
107 if (_heap->has_forwarded_objects() && _heap->in_collection_set(obj)) {
108 // Subsumes null-check
109 assert(obj != nullptr, "cset check must have subsumed null-check");
110 oop fwd = ShenandoahForwarding::get_forwardee(obj);
111 if (obj == fwd && _heap->is_evacuation_in_progress()) {
112 Thread* t = Thread::current();
113 return _heap->evacuate_object(obj, t);
114 }
115 return fwd;
116 }
117 return obj;
118 }
119
120 template <class T>
121 inline oop ShenandoahBarrierSet::load_reference_barrier(DecoratorSet decorators, oop obj, T* load_addr) {
122 if (obj == nullptr) {
123 return nullptr;
124 }
125
126 // Prevent resurrection of unreachable phantom (i.e. weak-native) references.
127 if ((decorators & ON_PHANTOM_OOP_REF) != 0 &&
128 _heap->is_concurrent_weak_root_in_progress() &&
129 _heap->is_in_active_generation(obj) &&
130 !_heap->marking_context()->is_marked(obj)) {
131 return nullptr;
132 }
133
134 // Prevent resurrection of unreachable weak references.
135 if ((decorators & ON_WEAK_OOP_REF) != 0 &&
136 _heap->is_concurrent_weak_root_in_progress() &&
137 _heap->is_in_active_generation(obj) &&
138 !_heap->marking_context()->is_marked_strong(obj)) {
139 return nullptr;
140 }
141
142 // Allow runtime to see unreachable objects that are visited during concurrent class-unloading.
143 if ((decorators & AS_NO_KEEPALIVE) != 0 &&
144 _heap->is_concurrent_weak_root_in_progress() &&
145 !_heap->marking_context()->is_marked(obj)) {
146 return obj;
147 }
148
149 oop fwd = load_reference_barrier(obj);
150 if (load_addr != nullptr && fwd != obj) {
151 // Since we are here and we know the load address, update the reference.
152 ShenandoahHeap::atomic_update_oop(fwd, load_addr, obj);
153 }
154
155 return fwd;
156 }
157
158 inline void ShenandoahBarrierSet::enqueue(oop obj, bool filter) {
159 assert(obj != nullptr, "checked by caller");
160 shenandoah_assert_correct(nullptr, obj);
161 assert(_satb_mark_queue_set.is_active(), "only get here when SATB active");
162
163 // Filter marked objects before hitting the SATB queues. The same predicate would
164 // be used by SATBMQ::filter to eliminate already marked objects downstream, but
165 // filtering here helps to avoid wasteful SATB queueing work to begin with.
166 if (filter && !_heap->requires_marking(obj)) return;
167
168 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(Thread::current());
169 _satb_mark_queue_set.enqueue_known_active(queue, obj);
170 }
171
172 template <DecoratorSet decorators, typename T>
173 inline void ShenandoahBarrierSet::satb_barrier(T *field) {
174 // Uninitialized and no-keepalive stores do not need barrier.
175 if (HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value ||
176 HasDecorator<decorators, AS_NO_KEEPALIVE>::value) {
177 return;
178 }
179
180 // Stores to weak/phantom require no barrier. The original references would
181 // have been enqueued in the SATB buffer by the load barrier if they were needed.
182 if (HasDecorator<decorators, ON_WEAK_OOP_REF>::value ||
183 HasDecorator<decorators, ON_PHANTOM_OOP_REF>::value) {
184 return;
185 }
186
187 if (ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
188 T heap_oop = RawAccess<>::oop_load(field);
189 if (!CompressedOops::is_null(heap_oop)) {
190 enqueue(CompressedOops::decode(heap_oop));
191 }
192 }
193 }
194
195 inline void ShenandoahBarrierSet::satb_enqueue(oop value) {
196 if (value != nullptr && ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
197 enqueue(value);
198 }
199 }
200
201 inline void ShenandoahBarrierSet::keep_alive_if_weak(DecoratorSet decorators, oop value) {
202 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
203 const bool on_strong_oop_ref = (decorators & ON_STRONG_OOP_REF) != 0;
204 const bool peek = (decorators & AS_NO_KEEPALIVE) != 0;
205 if (!peek && !on_strong_oop_ref) {
206 satb_enqueue(value);
207 }
208 }
209
210 template <DecoratorSet decorators, typename T>
211 inline void ShenandoahBarrierSet::write_ref_field_post(T* field) {
212 assert(ShenandoahCardBarrier, "Should have been checked by caller");
213 if (_heap->is_in_young(field)) {
214 // Young field stores do not require card mark.
215 return;
216 }
217 T heap_oop = RawAccess<>::oop_load(field);
218 if (CompressedOops::is_null(heap_oop)) {
219 // Null reference store do not require card mark.
220 return;
221 }
222 oop obj = CompressedOops::decode_not_null(heap_oop);
223 if (!_heap->is_in_young(obj)) {
224 // Not an old->young reference store.
225 return;
226 }
227 volatile CardTable::CardValue* byte = card_table()->byte_for(field);
228 *byte = CardTable::dirty_card_val();
229 }
230
231 template <typename T>
232 inline oop ShenandoahBarrierSet::oop_load(DecoratorSet decorators, T* addr) {
233 oop value = RawAccess<>::oop_load(addr);
234 value = load_reference_barrier(decorators, value, addr);
235 keep_alive_if_weak(decorators, value);
236 return value;
237 }
238
239 template <typename T>
240 inline oop ShenandoahBarrierSet::oop_cmpxchg(DecoratorSet decorators, T* addr, oop compare_value, oop new_value) {
241 shenandoah_assert_not_in_cset_except(nullptr, compare_value, (compare_value == nullptr || ShenandoahHeap::heap()->cancelled_gc()));
242 shenandoah_assert_not_in_cset_except(nullptr, new_value, (new_value == nullptr || ShenandoahHeap::heap()->cancelled_gc()));
243
244 // Handle the previous value through SATB, as we are about to perform the store.
245 oop prev = RawAccess<>::oop_load(addr);
246 satb_enqueue(prev);
247
248 // Perform LRB on location to fix it up for this and all following accesses.
249 // This guarantees there are no false negatives due to concurrent evacuation,
250 // and the value loaded later by CAS is sanitized by some LRB, or is null.
251 load_reference_barrier(decorators, prev, addr);
252
253 return RawAccess<>::oop_atomic_cmpxchg(addr, compare_value, new_value);
254 }
255
256 template <typename T>
257 inline oop ShenandoahBarrierSet::oop_xchg(DecoratorSet decorators, T* addr, oop new_value) {
258 shenandoah_assert_not_in_cset_except(nullptr, new_value, (new_value == nullptr || ShenandoahHeap::heap()->cancelled_gc()));
259
260 // Handle the previous value through SATB, as we are about to perform the store.
261 oop prev = RawAccess<>::oop_load(addr);
262 satb_enqueue(prev);
263
264 // Perform LRB on location to fix it up for this and all following accesses.
265 // This is purely opportunistic: we would not have any false negatives here.
266 // This guarantees the value loaded later by XCHG is sanitized by some LRB, or is null.
267 load_reference_barrier(decorators, prev, addr);
268
269 return RawAccess<>::oop_atomic_xchg(addr, new_value);
270 }
271
272 template <DecoratorSet decorators, typename BarrierSetT>
273 template <typename T>
274 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_not_in_heap(T* addr) {
275 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "must be absent");
276 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
277 return bs->oop_load(decorators, addr);
278 }
279
280 template <DecoratorSet decorators, typename BarrierSetT>
281 template <typename T>
282 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap(T* addr) {
283 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "must be absent");
284 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
285 return bs->oop_load(decorators, addr);
286 }
287
288 template <DecoratorSet decorators, typename BarrierSetT>
289 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap_at(oop base, ptrdiff_t offset) {
290 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
291 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
292 return bs->oop_load(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset));
293 }
294
295 template <DecoratorSet decorators, typename BarrierSetT>
296 template <typename T>
297 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_common(T* addr, oop value) {
298 shenandoah_assert_marked_if(nullptr, value,
299 !CompressedOops::is_null(value) && ShenandoahHeap::heap()->is_evacuation_in_progress()
300 && !(ShenandoahHeap::heap()->active_generation()->is_young()
301 && ShenandoahHeap::heap()->heap_region_containing(value)->is_old()));
302 shenandoah_assert_not_in_cset_if(addr, value, value != nullptr && !ShenandoahHeap::heap()->cancelled_gc());
303 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
304 bs->satb_barrier<decorators>(addr);
305 Raw::oop_store(addr, value);
306 }
307
308 template <DecoratorSet decorators, typename BarrierSetT>
309 template <typename T>
310 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_not_in_heap(T* addr, oop value) {
311 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
312 oop_store_common(addr, value);
313 }
314
315 template <DecoratorSet decorators, typename BarrierSetT>
316 template <typename T>
317 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap(T* addr, oop value) {
318 shenandoah_assert_not_in_cset_loc_except(addr, ShenandoahHeap::heap()->cancelled_gc());
319 shenandoah_assert_not_forwarded_except (addr, value, value == nullptr || ShenandoahHeap::heap()->cancelled_gc() || !ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
320
321 oop_store_common(addr, value);
322 if (ShenandoahCardBarrier) {
323 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
324 bs->write_ref_field_post<decorators>(addr);
325 }
326 }
327
328 template <DecoratorSet decorators, typename BarrierSetT>
329 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
330 oop_store_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), value);
331 }
332
333 template <DecoratorSet decorators, typename BarrierSetT>
334 template <typename T>
335 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_not_in_heap(T* addr, oop compare_value, oop new_value) {
336 assert((decorators & AS_NO_KEEPALIVE) == 0, "CAS only with keep-alive");
337 assert((decorators & ON_STRONG_OOP_REF) != 0, "CAS only for strong refs");
338 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
339 return bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
340 }
341
342 template <DecoratorSet decorators, typename BarrierSetT>
343 template <typename T>
344 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
345 assert((decorators & AS_NO_KEEPALIVE) == 0, "CAS only with keep-alive");
346 assert((decorators & ON_STRONG_OOP_REF) != 0, "CAS only for strong refs");
347 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
348 oop result = bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
349 if (ShenandoahCardBarrier) {
350 bs->write_ref_field_post<decorators>(addr);
351 }
352 return result;
353 }
354
355 template <DecoratorSet decorators, typename BarrierSetT>
356 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, oop compare_value, oop new_value) {
357 assert((decorators & AS_NO_KEEPALIVE) == 0, "CAS only with keep-alive");
358 assert((decorators & (ON_STRONG_OOP_REF | ON_UNKNOWN_OOP_REF)) != 0, "CAS only for strong refs OR unknown refs (Unsafe)");
359 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
360
361 // Unsafe.compareAndExchange/Set come here with ON_UNKNOWN_OOP_REF set.
362 // These are normally strong refs, but one can use Unsafe on Reference.referent.
363 // We cannot deal with that case. If application does Unsafe operations on
364 // Reference.referent field, this likely breaks weak reference semantics already.
365 // We upgrade the access to strong in (sometimes futile) attempt to maintain heap
366 // integrity, and assert in debug builds for better diagnostics.
367 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
368 assert((resolved_decorators & ON_STRONG_OOP_REF) != 0, "Application error: CAS on weak location");
369 resolved_decorators = (resolved_decorators & ~ON_DECORATOR_MASK) | ON_STRONG_OOP_REF;
370
371 auto addr = AccessInternal::oop_field_addr<decorators>(base, offset);
372 oop result = bs->oop_cmpxchg(resolved_decorators, addr, compare_value, new_value);
373 if (ShenandoahCardBarrier) {
374 bs->write_ref_field_post<decorators>(addr);
375 }
376 return result;
377 }
378
379 template <DecoratorSet decorators, typename BarrierSetT>
380 template <typename T>
381 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_not_in_heap(T* addr, oop new_value) {
382 assert((decorators & AS_NO_KEEPALIVE) == 0, "XCHG only with keep-alive");
383 assert((decorators & ON_STRONG_OOP_REF) != 0, "XCHG only for strong refs");
384 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
385 return bs->oop_xchg(decorators, addr, new_value);
386 }
387
388 template <DecoratorSet decorators, typename BarrierSetT>
389 template <typename T>
390 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap(T* addr, oop new_value) {
391 assert((decorators & AS_NO_KEEPALIVE) == 0, "XCHG only with keep-alive");
392 assert((decorators & ON_STRONG_OOP_REF) != 0, "XCHG only for strong refs");
393 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
394 oop result = bs->oop_xchg(decorators, addr, new_value);
395 if (ShenandoahCardBarrier) {
396 bs->write_ref_field_post<decorators>(addr);
397 }
398 return result;
399 }
400
401 template <DecoratorSet decorators, typename BarrierSetT>
402 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, oop new_value) {
403 assert((decorators & AS_NO_KEEPALIVE) == 0, "XCHG only with keep-alive");
404 assert((decorators & (ON_STRONG_OOP_REF | ON_UNKNOWN_OOP_REF)) != 0, "XCHG only for strong refs OR unknown refs (Unsafe)");
405 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
406
407 // Unsafe.getAndSet comes here with ON_UNKNOWN_OOP_REF set.
408 // These are normally strong refs, but one can use Unsafe on Reference.referent.
409 // We cannot deal with that case. If application does Unsafe operations on
410 // Reference.referent field, this likely breaks weak reference semantics already.
411 // We upgrade the access to strong in (sometimes futile) attempt to maintain heap
412 // integrity, and assert in debug builds for better diagnostics.
413 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
414 assert((resolved_decorators & ON_STRONG_OOP_REF) != 0, "Application error: XCHG on weak location");
415 resolved_decorators = (resolved_decorators & ~ON_DECORATOR_MASK) | ON_STRONG_OOP_REF;
416
417 auto addr = AccessInternal::oop_field_addr<decorators>(base, offset);
418 oop result = bs->oop_xchg(resolved_decorators, addr, new_value);
419 if (ShenandoahCardBarrier) {
420 bs->write_ref_field_post<decorators>(addr);
421 }
422 return result;
423 }
424
425 // Clone barrier support
426 template <bool EVAC>
427 class ShenandoahUpdateEvacForCloneOopClosure : public BasicOopIterateClosure {
428 private:
429 ShenandoahHeap* const _heap;
430 const ShenandoahCollectionSet* const _cset;
431 Thread* const _thread;
432
433 template <class T>
434 inline void do_oop_work(T* p) {
435 T o = RawAccess<>::oop_load(p);
436 if (!CompressedOops::is_null(o)) {
437 oop obj = CompressedOops::decode_not_null(o);
438 if (_cset->is_in(obj)) {
439 oop fwd = ShenandoahForwarding::get_forwardee(obj);
440 if (EVAC && obj == fwd) {
441 fwd = _heap->evacuate_object(obj, _thread);
442 }
443 shenandoah_assert_forwarded_except(p, obj, _heap->cancelled_gc());
444 ShenandoahHeap::atomic_update_oop(fwd, p, o);
445 obj = fwd;
446 }
447 }
448 }
449
450 public:
451 ShenandoahUpdateEvacForCloneOopClosure() :
452 _heap(ShenandoahHeap::heap()),
453 _cset(_heap->collection_set()),
454 _thread(Thread::current()) {}
455
456 virtual void do_oop(oop* p) { do_oop_work(p); }
457 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
458 };
459
460 template <bool EVAC>
461 void ShenandoahBarrierSet::clone_work(oop obj) {
462 if (need_bulk_update(cast_from_oop<HeapWord*>(obj))) {
463 ShenandoahUpdateEvacForCloneOopClosure<EVAC> cl;
464 obj->oop_iterate(&cl);
465 }
466 }
467
468 template <DecoratorSet decorators, typename BarrierSetT>
469 void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::clone_in_heap(oop src, oop dst, size_t size) {
470 // Hot code path, called from compiler/runtime. Make sure fast path is fast.
471
472 // Fix up src before doing the copy, if needed.
473 const char gc_state = ShenandoahThreadLocalData::gc_state(Thread::current());
474 if (gc_state != 0 && ShenandoahCloneBarrier) {
475 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
476 if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
477 bs->clone_work<true>(src);
478 } else if ((gc_state & ShenandoahHeap::UPDATE_REFS) != 0) {
479 bs->clone_work<false>(src);
480 }
481 }
482
483 Raw::clone(src, dst, size);
484
485 // Current allocator never allocates in old, so clone destination is guaranteed to be in young.
486 // Otherwise we need card barriers.
487 shenandoah_assert_in_young_if(nullptr, dst, ShenandoahCardBarrier);
488 }
489
490 template <DecoratorSet decorators, typename BarrierSetT>
491 void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::value_copy_in_heap(const ValuePayload& src, const ValuePayload& dst) {
492 precond(src.klass() == dst.klass());
493
494 const InlineKlass* md = src.klass();
495 if (!md->contains_oops()) {
496 // If we do not have oops in the flat array, we can just do a raw copy.
497 Raw::value_copy(src, dst);
498 } else {
499 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
500 // addr() points at the payload start, the oop map offset are relative to
501 // the object header, adjust address to account for this discrepancy.
502 const address oop_map_adjusted_src_addr = src.addr() - md->payload_offset();
503 const address oop_map_adjusted_dst_addr = dst.addr() - md->payload_offset();
504 typedef typename ValueOopType<decorators>::type OopType;
505
506 // Oop maps tell us where the array-like structures are in the value payload.
507 // For simplicity, apply arraycopy barriers over them.
508 bool dest_uninit = HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value;
509 {
510 OopMapBlock* map = md->start_of_nonstatic_oop_maps();
511 OopMapBlock* const end = map + md->nonstatic_oop_map_count();
512
513 while (map != end) {
514 address src_oop_address = oop_map_adjusted_src_addr + map->offset();
515 address dst_oop_address = oop_map_adjusted_dst_addr + map->offset();
516 bs->arraycopy_barrier((OopType*) src_oop_address, (OopType*) dst_oop_address, map->count(), dest_uninit);
517 map++;
518 }
519 }
520
521 Raw::value_copy(src, dst);
522
523 // Similarly, we can ask for ref array store helper for post-barriers.
524 if (ShenandoahCardBarrier) {
525 OopMapBlock* map = md->start_of_nonstatic_oop_maps();
526 OopMapBlock* const end = map + md->nonstatic_oop_map_count();
527 while (map != end) {
528 address dst_oop_address = oop_map_adjusted_dst_addr + map->offset();
529 bs->write_ref_array((HeapWord*) dst_oop_address, map->count());
530 map++;
531 }
532 }
533 }
534 }
535
536 template <DecoratorSet decorators, typename BarrierSetT>
537 void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::value_store_null_in_heap(const ValuePayload& dst) {
538 const InlineKlass* md = dst.klass();
539 if (!md->contains_oops()) {
540 // If we do not have oops in the flat array, we can just do a raw clear.
541 Raw::value_store_null(dst);
542 } else {
543 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
544 // addr() points at the payload start, the oop map offset are relative to
545 // the object header, adjust address to account for this discrepancy.
546 const address oop_map_adjusted_dst_addr = dst.addr() - md->payload_offset();
547 typedef typename ValueOopType<decorators>::type OopType;
548
549 // Oop maps tell us where the array-like structures are in the value payload.
550 // For simplicity, apply arraycopy barriers over them.
551 bool dest_uninit = HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value;
552 if (!dest_uninit) {
553 OopMapBlock* map = md->start_of_nonstatic_oop_maps();
554 OopMapBlock* const end = map + md->nonstatic_oop_map_count();
555 while (map != end) {
556 address dst_oop_address = oop_map_adjusted_dst_addr + map->offset();
557 bs->arraycopy_barrier((OopType*) dst_oop_address, (OopType*) dst_oop_address, map->count(), dest_uninit);
558 map++;
559 }
560 }
561
562 Raw::value_store_null(dst);
563
564 // Storing null does not require post-barriers
565 }
566 }
567
568 template <DecoratorSet decorators, typename BarrierSetT>
569 template <typename T>
570 OopCopyResult ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
571 arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
572 size_t length) {
573 T* src = arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw);
574 T* dst = arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw);
575 bool dest_uninit = HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value;
576
577 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
578 bs->arraycopy_barrier(src, dst, length, dest_uninit);
579 OopCopyResult result = Raw::oop_arraycopy_in_heap(src_obj, src_offset_in_bytes, src_raw, dst_obj, dst_offset_in_bytes, dst_raw, length);
580 if (ShenandoahCardBarrier) {
581 bs->write_ref_array((HeapWord*) dst, length);
582 }
583 return result;
584 }
585
586 template <class T, bool HAS_FWD, bool EVAC, bool ENQUEUE>
587 void ShenandoahBarrierSet::arraycopy_work(T* src, size_t count) {
588 // Young cycles are allowed to run when old marking is in progress. When old marking is in progress,
589 // this barrier will be called with ENQUEUE=true and HAS_FWD=false, even though the young generation
590 // may have forwarded objects.
591 assert(HAS_FWD == _heap->has_forwarded_objects() || _heap->is_concurrent_old_mark_in_progress(), "Forwarded object status is sane");
592 // This function cannot be called to handle marking and evacuation at the same time (they operate on
593 // different sides of the copy).
594 static_assert((HAS_FWD || EVAC) != ENQUEUE, "Cannot evacuate and mark both sides of copy.");
595
596 Thread* thread = Thread::current();
597 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
598 ShenandoahMarkingContext* ctx = _heap->marking_context();
599 const ShenandoahCollectionSet* const cset = _heap->collection_set();
600 T* end = src + count;
601 for (T* elem_ptr = src; elem_ptr < end; elem_ptr++) {
602 T o = RawAccess<>::oop_load(elem_ptr);
603 if (!CompressedOops::is_null(o)) {
604 oop obj = CompressedOops::decode_not_null(o);
605 if (HAS_FWD && cset->is_in(obj)) {
606 oop fwd = ShenandoahForwarding::get_forwardee(obj);
607 if (EVAC && obj == fwd) {
608 fwd = _heap->evacuate_object(obj, thread);
609 }
610 shenandoah_assert_forwarded_except(elem_ptr, obj, _heap->cancelled_gc());
611 ShenandoahHeap::atomic_update_oop(fwd, elem_ptr, o);
612 }
613 if (ENQUEUE && !ctx->is_marked_strong(obj)) {
614 _satb_mark_queue_set.enqueue_known_active(queue, obj);
615 }
616 }
617 }
618 }
619
620 template <class T>
621 void ShenandoahBarrierSet::arraycopy_barrier(T* src, T* dst, size_t count, bool dest_uninit) {
622 if (count == 0) {
623 // No elements to copy, no need for barrier
624 return;
625 }
626
627 const char gc_state = ShenandoahThreadLocalData::gc_state(Thread::current());
628 if (!dest_uninit && (gc_state & ShenandoahHeap::MARKING) != 0) {
629 // If marking old or young, we must evaluate the SATB barrier. This will be the only
630 // action if we are not marking old. If we are marking old, we must still evaluate the
631 // load reference barrier for a young collection.
632 if (_heap->mode()->is_generational()) {
633 arraycopy_marking<true>(dst, count);
634 } else {
635 arraycopy_marking<false>(dst, count);
636 }
637 }
638
639 if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
640 assert((gc_state & ShenandoahHeap::YOUNG_MARKING) == 0, "Cannot be marking young during evacuation");
641 arraycopy_evacuation(src, count);
642 } else if ((gc_state & ShenandoahHeap::UPDATE_REFS) != 0) {
643 assert((gc_state & ShenandoahHeap::YOUNG_MARKING) == 0, "Cannot be marking young during update-refs");
644 arraycopy_update(src, count);
645 }
646 }
647
648 template <bool IS_GENERATIONAL, class T>
649 void ShenandoahBarrierSet::arraycopy_marking(T* dst, size_t count) {
650 assert(_heap->is_concurrent_mark_in_progress(), "only during marking");
651 if (ShenandoahSATBBarrier) {
652 if (!_heap->marking_context()->allocated_after_mark_start(reinterpret_cast<HeapWord*>(dst)) ||
653 (IS_GENERATIONAL && _heap->heap_region_containing(dst)->is_old() && _heap->is_concurrent_young_mark_in_progress())) {
654 arraycopy_work<T, false, false, true>(dst, count);
655 }
656 }
657 }
658
659 inline bool ShenandoahBarrierSet::need_bulk_update(HeapWord* ary) {
660 return ary < _heap->heap_region_containing(ary)->get_update_watermark();
661 }
662
663 template <class T>
664 void ShenandoahBarrierSet::arraycopy_evacuation(T* src, size_t count) {
665 assert(_heap->is_evacuation_in_progress(), "only during evacuation");
666 if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
667 arraycopy_work<T, true, true, false>(src, count);
668 }
669 }
670
671 template <class T>
672 void ShenandoahBarrierSet::arraycopy_update(T* src, size_t count) {
673 assert(_heap->is_update_refs_in_progress(), "only during update-refs");
674 if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
675 arraycopy_work<T, true, false, false>(src, count);
676 }
677 }
678
679 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP