1 /*
   2  * Copyright (c) 2015, 2020, 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.
  22  *
  23  */
  24 
  25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
  26 #define SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP
  27 
  28 #include "gc/shared/barrierSet.hpp"
  29 #include "gc/shenandoah/shenandoahAsserts.hpp"
  30 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
  31 #include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"
  32 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
  33 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
  34 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
  35 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
  36 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
  37 #include "memory/iterator.inline.hpp"
  38 #include "oops/oop.inline.hpp"
  39 
  40 inline oop ShenandoahBarrierSet::resolve_forwarded_not_null(oop p) {
  41   return ShenandoahForwarding::get_forwardee(p);
  42 }
  43 
  44 inline oop ShenandoahBarrierSet::resolve_forwarded(oop p) {
  45   if (p != NULL) {
  46     return resolve_forwarded_not_null(p);
  47   } else {
  48     return p;
  49   }
  50 }
  51 
  52 inline oop ShenandoahBarrierSet::resolve_forwarded_not_null_mutator(oop p) {
  53   return ShenandoahForwarding::get_forwardee_mutator(p);
  54 }
  55 
  56 template <class T>
  57 inline oop ShenandoahBarrierSet::load_reference_barrier_mutator(oop obj, T* load_addr) {
  58   assert(ShenandoahLoadRefBarrier, "should be enabled");
  59   shenandoah_assert_in_cset(load_addr, obj);
  60 
  61   oop fwd = resolve_forwarded_not_null_mutator(obj);
  62   if (obj == fwd) {
  63     assert(_heap->is_evacuation_in_progress(),
  64            "evac should be in progress");
  65     Thread* const t = Thread::current();
  66     fwd = _heap->evacuate_object(obj, t);
  67   }
  68 
  69   if (load_addr != NULL && fwd != obj) {
  70     // Since we are here and we know the load address, update the reference.
  71     ShenandoahHeap::cas_oop(fwd, load_addr, obj);
  72   }
  73 
  74   return fwd;
  75 }
  76 
  77 inline void ShenandoahBarrierSet::enqueue(oop obj) {
  78   assert(_satb_mark_queue_set.is_active(), "only get here when SATB active");
  79 
  80   // Filter marked objects before hitting the SATB queues. The same predicate would
  81   // be used by SATBMQ::filter to eliminate already marked objects downstream, but
  82   // filtering here helps to avoid wasteful SATB queueing work to begin with.
  83   if (!_heap->requires_marking<false>(obj)) return;
  84 
  85   ShenandoahThreadLocalData::satb_mark_queue(Thread::current()).enqueue_known_active(obj);
  86 }
  87 
  88 template <DecoratorSet decorators, typename T>
  89 inline void ShenandoahBarrierSet::satb_barrier(T *field) {
  90   if (HasDecorator<decorators, IS_DEST_UNINITIALIZED>::value ||
  91       HasDecorator<decorators, AS_NO_KEEPALIVE>::value) {
  92     return;
  93   }
  94   if (ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
  95     T heap_oop = RawAccess<>::oop_load(field);
  96     if (!CompressedOops::is_null(heap_oop)) {
  97       enqueue(CompressedOops::decode(heap_oop));
  98     }
  99   }
 100 }
 101 
 102 inline void ShenandoahBarrierSet::satb_enqueue(oop value) {
 103   assert(value != NULL, "checked before");
 104   if (ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
 105     enqueue(value);
 106   }
 107 }
 108 
 109 inline void ShenandoahBarrierSet::storeval_barrier(oop obj) {
 110   if (ShenandoahStoreValEnqueueBarrier && obj != NULL && _heap->is_concurrent_mark_in_progress()) {
 111     enqueue(obj);
 112   }
 113 }
 114 
 115 inline void ShenandoahBarrierSet::keep_alive_if_weak(DecoratorSet decorators, oop value) {
 116   assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
 117   const bool on_strong_oop_ref = (decorators & ON_STRONG_OOP_REF) != 0;
 118   const bool peek              = (decorators & AS_NO_KEEPALIVE) != 0;
 119   if (!peek && !on_strong_oop_ref) {
 120     satb_enqueue(value);
 121   }
 122 }
 123 
 124 template <DecoratorSet decorators>
 125 inline void ShenandoahBarrierSet::keep_alive_if_weak(oop value) {
 126   assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Reference strength must be known");
 127   if (!HasDecorator<decorators, ON_STRONG_OOP_REF>::value &&
 128       !HasDecorator<decorators, AS_NO_KEEPALIVE>::value) {
 129     satb_enqueue(value);
 130   }
 131 }
 132 
 133 template <DecoratorSet decorators, typename BarrierSetT>
 134 template <typename T>
 135 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_not_in_heap(T* addr) {
 136   oop value = Raw::oop_load_not_in_heap(addr);
 137   if (value != NULL) {
 138     ShenandoahBarrierSet *const bs = ShenandoahBarrierSet::barrier_set();
 139     value = bs->load_reference_barrier_native(value, addr);
 140     if (value != NULL) {
 141       bs->keep_alive_if_weak<decorators>(value);
 142     }
 143   }
 144   return value;
 145 }
 146 
 147 template <DecoratorSet decorators, typename BarrierSetT>
 148 template <typename T>
 149 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap(T* addr) {
 150   oop value = Raw::oop_load_in_heap(addr);
 151   if (value != NULL) {
 152     ShenandoahBarrierSet *const bs = ShenandoahBarrierSet::barrier_set();
 153     value = bs->load_reference_barrier_not_null(value);
 154     bs->keep_alive_if_weak<decorators>(value);
 155   }
 156   return value;
 157 }
 158 
 159 template <DecoratorSet decorators, typename BarrierSetT>
 160 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_load_in_heap_at(oop base, ptrdiff_t offset) {
 161   oop value = Raw::oop_load_in_heap_at(base, offset);
 162   if (value != NULL) {
 163     ShenandoahBarrierSet *const bs = ShenandoahBarrierSet::barrier_set();
 164     value = bs->load_reference_barrier_not_null(value);
 165     bs->keep_alive_if_weak(AccessBarrierSupport::resolve_possibly_unknown_oop_ref_strength<decorators>(base, offset),
 166                            value);
 167   }
 168   return value;
 169 }
 170 
 171 template <DecoratorSet decorators, typename BarrierSetT>
 172 template <typename T>
 173 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_not_in_heap(T* addr, oop value) {
 174   shenandoah_assert_marked_if(NULL, value, !CompressedOops::is_null(value) && ShenandoahHeap::heap()->is_evacuation_in_progress());
 175   ShenandoahBarrierSet* const bs = ShenandoahBarrierSet::barrier_set();
 176   bs->storeval_barrier(value);
 177   bs->satb_barrier<decorators>(addr);
 178   Raw::oop_store(addr, value);
 179 }
 180 
 181 template <DecoratorSet decorators, typename BarrierSetT>
 182 template <typename T>
 183 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap(T* addr, oop value) {
 184   shenandoah_assert_not_in_cset_loc_except(addr, ShenandoahHeap::heap()->cancelled_gc());
 185   shenandoah_assert_not_forwarded_except  (addr, value, value == NULL || ShenandoahHeap::heap()->cancelled_gc() || !ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
 186   shenandoah_assert_not_in_cset_except    (addr, value, value == NULL || ShenandoahHeap::heap()->cancelled_gc() || !ShenandoahHeap::heap()->is_concurrent_mark_in_progress());
 187 
 188   oop_store_not_in_heap(addr, value);
 189 }
 190 
 191 template <DecoratorSet decorators, typename BarrierSetT>
 192 inline void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_store_in_heap_at(oop base, ptrdiff_t offset, oop value) {
 193   oop_store_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), value);
 194 }
 195 
 196 template <DecoratorSet decorators, typename BarrierSetT>
 197 template <typename T>
 198 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_not_in_heap(T* addr, oop compare_value, oop new_value) {
 199   ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
 200   bs->storeval_barrier(new_value);
 201 
 202   oop res;
 203   oop expected = compare_value;
 204   do {
 205     compare_value = expected;
 206     res = Raw::oop_atomic_cmpxchg(addr, compare_value, new_value);
 207     expected = res;
 208   } while ((compare_value != expected) && (resolve_forwarded(compare_value) == resolve_forwarded(expected)));
 209 
 210   // Note: We don't need a keep-alive-barrier here. We already enqueue any loaded reference for SATB anyway,
 211   // because it must be the previous value.
 212   if (res != NULL) {
 213     res = ShenandoahBarrierSet::barrier_set()->load_reference_barrier_not_null(res);
 214     bs->satb_enqueue(res);
 215   }
 216   return res;
 217 }
 218 
 219 template <DecoratorSet decorators, typename BarrierSetT>
 220 template <typename T>
 221 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap(T* addr, oop compare_value, oop new_value) {
 222   return oop_atomic_cmpxchg_not_in_heap(addr, compare_value, new_value);
 223 }
 224 
 225 template <DecoratorSet decorators, typename BarrierSetT>
 226 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_cmpxchg_in_heap_at(oop base, ptrdiff_t offset, oop compare_value, oop new_value) {
 227   return oop_atomic_cmpxchg_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), compare_value, new_value);
 228 }
 229 
 230 template <DecoratorSet decorators, typename BarrierSetT>
 231 template <typename T>
 232 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_not_in_heap(T* addr, oop new_value) {
 233   ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
 234   bs->storeval_barrier(new_value);
 235 
 236   oop previous = Raw::oop_atomic_xchg(addr, new_value);
 237 
 238   // Note: We don't need a keep-alive-barrier here. We already enqueue any loaded reference for SATB anyway,
 239   // because it must be the previous value.
 240   if (previous != NULL) {
 241     previous = ShenandoahBarrierSet::barrier_set()->load_reference_barrier_not_null(previous);
 242     bs->satb_enqueue(previous);
 243   }
 244   return previous;
 245 }
 246 
 247 template <DecoratorSet decorators, typename BarrierSetT>
 248 template <typename T>
 249 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap(T* addr, oop new_value) {
 250   return oop_atomic_xchg_not_in_heap(addr, new_value);
 251 }
 252 
 253 template <DecoratorSet decorators, typename BarrierSetT>
 254 inline oop ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_atomic_xchg_in_heap_at(oop base, ptrdiff_t offset, oop new_value) {
 255   return oop_atomic_xchg_in_heap(AccessInternal::oop_field_addr<decorators>(base, offset), new_value);
 256 }
 257 
 258 // Clone barrier support
 259 template <DecoratorSet decorators, typename BarrierSetT>
 260 void ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::clone_in_heap(oop src, oop dst, size_t size) {
 261   if (ShenandoahCloneBarrier) {
 262     ShenandoahBarrierSet::barrier_set()->clone_barrier_runtime(src);
 263   }
 264   Raw::clone(src, dst, size);
 265 }
 266 
 267 template <DecoratorSet decorators, typename BarrierSetT>
 268 template <typename T>
 269 bool ShenandoahBarrierSet::AccessBarrier<decorators, BarrierSetT>::oop_arraycopy_in_heap(arrayOop src_obj, size_t src_offset_in_bytes, T* src_raw,
 270                                                                                          arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw,
 271                                                                                          size_t length) {
 272   ShenandoahBarrierSet* bs = ShenandoahBarrierSet::barrier_set();
 273   bs->arraycopy_barrier(arrayOopDesc::obj_offset_to_raw(src_obj, src_offset_in_bytes, src_raw),
 274                         arrayOopDesc::obj_offset_to_raw(dst_obj, dst_offset_in_bytes, dst_raw),
 275                         length);
 276   return Raw::oop_arraycopy_in_heap(src_obj, src_offset_in_bytes, src_raw, dst_obj, dst_offset_in_bytes, dst_raw, length);
 277 }
 278 
 279 template <class T, bool HAS_FWD, bool EVAC, bool ENQUEUE>
 280 void ShenandoahBarrierSet::arraycopy_work(T* src, size_t count) {
 281   assert(HAS_FWD == _heap->has_forwarded_objects(), "Forwarded object status is sane");
 282 
 283   Thread* thread = Thread::current();
 284   SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
 285   ShenandoahMarkingContext* ctx = _heap->marking_context();
 286   const ShenandoahCollectionSet* const cset = _heap->collection_set();
 287   T* end = src + count;
 288   for (T* elem_ptr = src; elem_ptr < end; elem_ptr++) {
 289     T o = RawAccess<>::oop_load(elem_ptr);
 290     if (!CompressedOops::is_null(o)) {
 291       oop obj = CompressedOops::decode_not_null(o);
 292       if (HAS_FWD && cset->is_in(obj)) {
 293         oop fwd = resolve_forwarded_not_null(obj);
 294         if (EVAC && obj == fwd) {
 295           fwd = _heap->evacuate_object(obj, thread);
 296         }
 297         assert(obj != fwd || _heap->cancelled_gc(), "must be forwarded");
 298         oop witness = ShenandoahHeap::cas_oop(fwd, elem_ptr, o);
 299         obj = fwd;
 300       }
 301       if (ENQUEUE && !ctx->is_marked(obj)) {
 302         queue.enqueue_known_active(obj);
 303       }
 304     }
 305   }
 306 }
 307 
 308 template <class T>
 309 void ShenandoahBarrierSet::arraycopy_barrier(T* src, T* dst, size_t count) {
 310   if (count == 0) {
 311     return;
 312   }
 313   int gc_state = _heap->gc_state();
 314   if ((gc_state & ShenandoahHeap::MARKING) != 0) {
 315     arraycopy_marking(src, dst, count);
 316   } else if ((gc_state & ShenandoahHeap::EVACUATION) != 0) {
 317     arraycopy_evacuation(src, count);
 318   } else if ((gc_state & ShenandoahHeap::UPDATEREFS) != 0) {
 319     arraycopy_update(src, count);
 320   }
 321 }
 322 
 323 template <class T>
 324 void ShenandoahBarrierSet::arraycopy_marking(T* src, T* dst, size_t count) {
 325   assert(_heap->is_concurrent_mark_in_progress(), "only during marking");
 326   T* array = ShenandoahSATBBarrier ? dst : src;
 327   if (!_heap->marking_context()->allocated_after_mark_start(reinterpret_cast<HeapWord*>(array))) {
 328     arraycopy_work<T, false, false, true>(array, count);
 329   }
 330 }
 331 
 332 inline bool ShenandoahBarrierSet::need_bulk_update(HeapWord* ary) {
 333   return ary < _heap->heap_region_containing(ary)->get_update_watermark();
 334 }
 335 
 336 template <class T>
 337 void ShenandoahBarrierSet::arraycopy_evacuation(T* src, size_t count) {
 338   assert(_heap->is_evacuation_in_progress(), "only during evacuation");
 339   if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
 340     arraycopy_work<T, true, true, false>(src, count);
 341   }
 342 }
 343 
 344 template <class T>
 345 void ShenandoahBarrierSet::arraycopy_update(T* src, size_t count) {
 346   assert(_heap->is_update_refs_in_progress(), "only during update-refs");
 347   if (need_bulk_update(reinterpret_cast<HeapWord*>(src))) {
 348     arraycopy_work<T, true, false, false>(src, count);
 349   }
 350 }
 351 
 352 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHBARRIERSET_INLINE_HPP