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::iu_barrier(oop obj) {
168 if (ShenandoahIUBarrier && obj != nullptr && _heap->is_concurrent_mark_in_progress()) {
169 enqueue(obj);
170 }
171 }
172
173 inline void ShenandoahBarrierSet::keep_alive_if_weak(DecoratorSet decorators, oop value) {
174 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
175 const bool on_strong_oop_ref = (decorators & ON_STRONG_OOP_REF) != 0;
176 const bool peek = (decorators & AS_NO_KEEPALIVE) != 0;
177 if (!peek && !on_strong_oop_ref) {
178 satb_enqueue(value);
179 }
180 }
181
182 template <typename T>
183 inline oop ShenandoahBarrierSet::oop_load(DecoratorSet decorators, T* addr) {
184 oop value = RawAccess<>::oop_load(addr);
185 value = load_reference_barrier(decorators, value, addr);
186 keep_alive_if_weak(decorators, value);
187 return value;
188 }
189
190 template <typename T>
191 inline oop ShenandoahBarrierSet::oop_cmpxchg(DecoratorSet decorators, T* addr, oop compare_value, oop new_value) {
192 iu_barrier(new_value);
193 oop res;
194 oop expected = compare_value;
195 do {
196 compare_value = expected;
197 res = RawAccess<>::oop_atomic_cmpxchg(addr, compare_value, new_value);
198 expected = res;
199 } while ((compare_value != expected) && (resolve_forwarded(compare_value) == resolve_forwarded(expected)));
200
201 // Note: We don't need a keep-alive-barrier here. We already enqueue any loaded reference for SATB anyway,
202 // because it must be the previous value.
203 res = load_reference_barrier(decorators, res, static_cast<T*>(nullptr));
204 satb_enqueue(res);
205 return res;
206 }
207
208 template <typename T>
209 inline oop ShenandoahBarrierSet::oop_xchg(DecoratorSet decorators, T* addr, oop new_value) {
210 iu_barrier(new_value);
211 oop previous = RawAccess<>::oop_atomic_xchg(addr, new_value);
212 // Note: We don't need a keep-alive-barrier here. We already enqueue any loaded reference for SATB anyway,
213 // because it must be the previous value.
214 previous = load_reference_barrier<T>(decorators, previous, static_cast<T*>(nullptr));
215 satb_enqueue(previous);
216 return previous;
217 }
218
219 template <DecoratorSet decorators, typename BarrierSetT>
220 template <typename T>
221 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_not_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 template <typename T>
229 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap(T* addr) {
230 assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "must be absent");
231 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
232 return bs->oop_load(decorators, addr);
233 }
234
235 template <DecoratorSet decorators, typename BarrierSetT>
236 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap_at(oop base, ptrdiff_t offset) {
237 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
238 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
239 return bs->oop_load(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset));
240 }
241
242 template <DecoratorSet decorators, typename BarrierSetT>
243 template <typename T>
244 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_common(T* addr, oop value) {
245 shenandoah_assert_marked_if(nullptr, value, !CompressedOops::is_null(value) && ShenandoahHeap::heap()->is_evacuation_in_progress());
246 shenandoah_assert_not_in_cset_if(addr, value, value != nullptr && !ShenandoahHeap::heap()->cancelled_gc());
247 ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
248 bs->iu_barrier(value);
249 bs->satb_barrier<decorators>(addr);
250 Raw::oop_store(addr, value);
251 }
252
253 template <DecoratorSet decorators, typename BarrierSetT>
254 template <typename T>
255 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_not_in_heap(T* addr, oop value) {
256 oop_store_common(addr, value);
257 }
258
259 template <DecoratorSet decorators, typename BarrierSetT>
260 template <typename T>
261 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap(T* addr, oop value) {
262 shenandoah_assert_not_in_cset_loc_except(addr, ShenandoahHeap::heap()->cancelled_gc());
263 shenandoah_assert_not_forwarded_except (addr, value, value == nullptr || ShenandoahHeap::heap()->cancelled_gc() || !ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
264
265 oop_store_common(addr, value);
266 }
267
268 template <DecoratorSet decorators, typename BarrierSetT>
269 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
270 oop_store_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), value);
271 }
272
273 template <DecoratorSet decorators, typename BarrierSetT>
274 template <typename T>
275 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_not_in_heap(T* addr, oop compare_value, oop new_value) {
276 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
277 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
278 return bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
279 }
280
281 template <DecoratorSet decorators, typename BarrierSetT>
282 template <typename T>
283 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
284 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
285 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
286 return bs->oop_cmpxchg(decorators, addr, compare_value, new_value);
287 }
288
289 template <DecoratorSet decorators, typename BarrierSetT>
290 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, oop compare_value, oop new_value) {
291 assert((decorators & AS_NO_KEEPALIVE) == 0, "must be absent");
292 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
293 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
294 return bs->oop_cmpxchg(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset), compare_value, new_value);
295 }
296
297 template <DecoratorSet decorators, typename BarrierSetT>
298 template <typename T>
299 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_not_in_heap(T* addr, oop new_value) {
300 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
301 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
302 return bs->oop_xchg(decorators, addr, new_value);
303 }
304
305 template <DecoratorSet decorators, typename BarrierSetT>
306 template <typename T>
307 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap(T* addr, oop new_value) {
308 assert((decorators & (AS_NO_KEEPALIVE | ON_UNKNOWN_OOP_REF)) == 0, "must be absent");
309 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
310 return bs->oop_xchg(decorators, addr, new_value);
311 }
312
313 template <DecoratorSet decorators, typename BarrierSetT>
314 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, oop new_value) {
315 assert((decorators & AS_NO_KEEPALIVE) == 0, "must be absent");
316 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
317 DecoratorSet resolved_decorators = AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset);
318 return bs->oop_xchg(resolved_decorators, AccessInternal::oop_field_addr<decorators>(base, offset), new_value);
319 }
320
321 // Clone barrier support
322 template <DecoratorSet decorators, typename BarrierSetT>
323 void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::clone_in_heap(oop src, oop dst, size_t size) {
324 if (ShenandoahCloneBarrier) {
325 ShenandoahBarrierSet::barrier_set()->clone_barrier_runtime(src);
326 }
327 Raw::clone(src, dst, size);
328 }
329
330 template <DecoratorSet decorators, typename BarrierSetT>
331 template <typename T>
332 bool ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
333 arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
334 size_t length) {
335 ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
336 bs->arraycopy_barrier(arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw),
337 arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw),
338 length);
339 return Raw::oop_arraycopy_in_heap(src_obj, src_offset_in_bytes, src_raw, dst_obj, dst_offset_in_bytes, dst_raw, length);
340 }
341
342 template <class T, bool HAS_FWD, bool EVAC, bool ENQUEUE>
343 void ShenandoahBarrierSet::arraycopy_work(T* src, size_t count) {
344 assert(HAS_FWD == _heap->has_forwarded_objects(), "Forwarded object status is sane");
345
346 Thread* thread = Thread::current();
347 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
348 ShenandoahMarkingContext* ctx = _heap->marking_context();
349 const ShenandoahCollectionSet* const cset = _heap->collection_set();
350 T* end = src + count;
351 for (T* elem_ptr = src; elem_ptr < end; elem_ptr++) {
352 T o = RawAccess<>::oop_load(elem_ptr);
353 if (!CompressedOops::is_null(o)) {
354 oop obj = CompressedOops::decode_not_null(o);
355 if (HAS_FWD && cset->is_in(obj)) {
356 oop fwd = resolve_forwarded_not_null(obj);
357 if (EVAC && obj == fwd) {
358 fwd = _heap->evacuate_object(obj, thread);
359 }
360 assert(obj != fwd || _heap->cancelled_gc(), "must be forwarded");
361 ShenandoahHeap::atomic_update_oop(fwd, elem_ptr, o);
362 obj = fwd;
363 }
364 if (ENQUEUE && !ctx->is_marked_strong(obj)) {
365 _satb_mark_queue_set.enqueue_known_active(queue, obj);
366 }
367 }
368 }
369 }
370
371 template <class T>
372 void ShenandoahBarrierSet::arraycopy_barrier(T* src, T* dst, size_t count) {
373 if (count == 0) {
374 return;
375 }
376 int gc_state = _heap->gc_state();
377 if ((gc_state & ShenandoahHeap::MARKING) != 0) {
378 arraycopy_marking(src, dst, count);
379 } else if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
380 arraycopy_evacuation(src, count);
381 } else if ((gc_state & ShenandoahHeap::UPDATEREFS) != 0) {
382 arraycopy_update(src, count);
383 }
384 }
385
386 template <class T>
387 void ShenandoahBarrierSet::arraycopy_marking(T* src, T* dst, size_t count) {
388 assert(_heap->is_concurrent_mark_in_progress(), "only during marking");
389 T* array = ShenandoahSATBBarrier ? dst : src;
390 if (!_heap->marking_context()->allocated_after_mark_start(reinterpret_cast<HeapWord*>(array))) {
391 arraycopy_work<T, false, false, true>(array, count);
392 }
393 }
394
395 inline bool ShenandoahBarrierSet::need_bulk_update(HeapWord* ary) {
396 return ary < _heap->heap_region_containing(ary)->get_update_watermark();
397 }
398
399 template <class T>
400 void ShenandoahBarrierSet::arraycopy_evacuation(T* src, size_t count) {
401 assert(_heap->is_evacuation_in_progress(), "only during evacuation");
402 if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
403 ShenandoahEvacOOMScope oom_evac;
404 arraycopy_work<T, true, true, false>(src, count);
405 }
406 }
407
408 template <class T>
409 void ShenandoahBarrierSet::arraycopy_update(T* src, size_t count) {
410 assert(_heap->is_update_refs_in_progress(), "only during update-refs");
411 if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
412 arraycopy_work<T, true, false, false>(src, count);
413 }
414 }
415
416 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP