1 /*
  2  * Copyright (c) 2013, 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.
 23  *
 24  */
 25 
 26 #include "precompiled.hpp"
 27 #include "gc/shared/barrierSetNMethod.hpp"
 28 #include "gc/shenandoah/shenandoahBarrierSetClone.inline.hpp"
 29 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
 30 #include "gc/shenandoah/shenandoahBarrierSetNMethod.hpp"
 31 #include "gc/shenandoah/shenandoahBarrierSetStackChunk.hpp"
 32 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
 33 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
 34 #include "gc/shenandoah/shenandoahStackWatermark.hpp"
 35 #ifdef COMPILER1
 36 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
 37 #endif
 38 #ifdef COMPILER2
 39 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
 40 #endif
 41 
 42 class ShenandoahBarrierSetC1;
 43 class ShenandoahBarrierSetC2;
 44 
 45 ShenandoahBarrierSet::ShenandoahBarrierSet(ShenandoahHeap* heap, MemRegion heap_region) :
 46   BarrierSet(make_barrier_set_assembler<ShenandoahBarrierSetAssembler>(),
 47              make_barrier_set_c1<ShenandoahBarrierSetC1>(),
 48              make_barrier_set_c2<ShenandoahBarrierSetC2>(),
 49              new ShenandoahBarrierSetNMethod(heap),
 50              new ShenandoahBarrierSetStackChunk(),
 51              BarrierSet::FakeRtti(BarrierSet::ShenandoahBarrierSet)),
 52   _heap(heap),
 53   _satb_mark_queue_buffer_allocator("SATB Buffer Allocator", ShenandoahSATBBufferSize),
 54   _satb_mark_queue_set(&_satb_mark_queue_buffer_allocator)
 55 {
 56   if (ShenandoahCardBarrier) {
 57     _card_table = new ShenandoahCardTable(heap_region);
 58     _card_table->initialize();
 59   }
 60 }
 61 
 62 ShenandoahBarrierSetAssembler* ShenandoahBarrierSet::assembler() {
 63   BarrierSetAssembler* const bsa = BarrierSet::barrier_set()->barrier_set_assembler();
 64   return reinterpret_cast<ShenandoahBarrierSetAssembler*>(bsa);
 65 }
 66 
 67 void ShenandoahBarrierSet::print_on(outputStream* st) const {
 68   st->print("ShenandoahBarrierSet");
 69 }
 70 
 71 bool ShenandoahBarrierSet::need_load_reference_barrier(DecoratorSet decorators, BasicType type) {
 72   if (!ShenandoahLoadRefBarrier) return false;
 73   // Only needed for references
 74   return is_reference_type(type);
 75 }
 76 
 77 bool ShenandoahBarrierSet::need_keep_alive_barrier(DecoratorSet decorators, BasicType type) {
 78   if (!ShenandoahSATBBarrier) return false;
 79   // Only needed for references
 80   if (!is_reference_type(type)) return false;
 81 
 82   bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0;
 83   bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0;
 84   bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0;
 85   return (on_weak_ref || unknown) && keep_alive;
 86 }
 87 
 88 void ShenandoahBarrierSet::on_thread_create(Thread* thread) {
 89   // Create thread local data
 90   ShenandoahThreadLocalData::create(thread);
 91 }
 92 
 93 void ShenandoahBarrierSet::on_thread_destroy(Thread* thread) {
 94   // Destroy thread local data
 95   ShenandoahThreadLocalData::destroy(thread);
 96 }
 97 
 98 void ShenandoahBarrierSet::on_thread_attach(Thread *thread) {
 99   assert(!thread->is_Java_thread() || !SafepointSynchronize::is_at_safepoint(),
100          "We should not be at a safepoint");
101   SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
102   assert(!queue.is_active(), "SATB queue should not be active");
103   assert(queue.buffer() == nullptr, "SATB queue should not have a buffer");
104   assert(queue.index() == 0, "SATB queue index should be zero");
105   queue.set_active(_satb_mark_queue_set.is_active());
106   if (thread->is_Java_thread()) {
107     ShenandoahThreadLocalData::set_gc_state(thread, _heap->gc_state());
108     ShenandoahThreadLocalData::initialize_gclab(thread);
109 
110     BarrierSetNMethod* bs_nm = barrier_set_nmethod();
111     if (bs_nm != nullptr) {
112       thread->set_nmethod_disarmed_guard_value(bs_nm->disarmed_guard_value());
113     }
114 
115     if (ShenandoahStackWatermarkBarrier) {
116       JavaThread* const jt = JavaThread::cast(thread);
117       StackWatermark* const watermark = new ShenandoahStackWatermark(jt);
118       StackWatermarkSet::add_watermark(jt, watermark);
119     }
120   }
121 }
122 
123 void ShenandoahBarrierSet::on_thread_detach(Thread *thread) {
124   SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
125   _satb_mark_queue_set.flush_queue(queue);
126   if (thread->is_Java_thread()) {
127     PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
128     if (gclab != nullptr) {
129       gclab->retire();
130     }
131 
132     PLAB* plab = ShenandoahThreadLocalData::plab(thread);
133     // CAUTION: retire_plab may register the remnant filler object with the remembered set scanner without a lock.
134     // This is safe iff it is assured that each PLAB is a whole-number multiple of card-mark memory size and each
135     // PLAB is aligned with the start of each card's memory range.
136     // TODO: Assert this in retire_plab?
137     if (plab != nullptr) {
138       _heap->retire_plab(plab);
139     }
140 
141     // SATB protocol requires to keep alive reachable oops from roots at the beginning of GC
142     if (ShenandoahStackWatermarkBarrier) {
143       if (_heap->is_concurrent_mark_in_progress()) {
144         ShenandoahKeepAliveClosure oops;
145         StackWatermarkSet::finish_processing(JavaThread::cast(thread), &oops, StackWatermarkKind::gc);
146       } else if (_heap->is_concurrent_weak_root_in_progress() && _heap->is_evacuation_in_progress()) {
147         ShenandoahContextEvacuateUpdateRootsClosure oops;
148         StackWatermarkSet::finish_processing(JavaThread::cast(thread), &oops, StackWatermarkKind::gc);
149       }
150     }
151   }
152 }
153 
154 void ShenandoahBarrierSet::clone_barrier_runtime(oop src) {
155   if (_heap->has_forwarded_objects() || (ShenandoahIUBarrier && _heap->is_concurrent_mark_in_progress())) {
156     clone_barrier(src);
157   }
158 }
159 
160 void ShenandoahBarrierSet::write_ref_array(HeapWord* start, size_t count) {
161   assert(ShenandoahCardBarrier, "Did you mean to enable ShenandoahCardBarrier?");
162 
163   HeapWord* end = (HeapWord*)((char*) start + (count * heapOopSize));
164   // In the case of compressed oops, start and end may potentially be misaligned;
165   // so we need to conservatively align the first downward (this is not
166   // strictly necessary for current uses, but a case of good hygiene and,
167   // if you will, aesthetics) and the second upward (this is essential for
168   // current uses) to a HeapWord boundary, so we mark all cards overlapping
169   // this write.
170   HeapWord* aligned_start = align_down(start, HeapWordSize);
171   HeapWord* aligned_end   = align_up  (end,   HeapWordSize);
172   // If compressed oops were not being used, these should already be aligned
173   assert(UseCompressedOops || (aligned_start == start && aligned_end == end),
174          "Expected heap word alignment of start and end");
175   _heap->card_scan()->mark_range_as_dirty(aligned_start, (aligned_end - aligned_start));
176 }
177