--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp	Mon Dec 10 15:47:44 2018 +0100
@@ -0,0 +1,376 @@
+/*
+ * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "gc/g1/g1BarrierSet.hpp"
+#include "gc/shenandoah/shenandoahAsserts.hpp"
+#include "gc/shenandoah/shenandoahBarrierSet.hpp"
+#include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
+#include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
+#include "gc/shenandoah/shenandoahHeap.inline.hpp"
+#include "gc/shenandoah/shenandoahHeuristics.hpp"
+#include "gc/shenandoah/shenandoahTraversalGC.hpp"
+#include "memory/iterator.inline.hpp"
+#include "runtime/interfaceSupport.inline.hpp"
+#ifdef COMPILER1
+#include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp"
+#endif
+#ifdef COMPILER2
+#include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
+#endif
+
+class ShenandoahBarrierSetC1;
+class ShenandoahBarrierSetC2;
+
+template <bool STOREVAL_WRITE_BARRIER>
+class ShenandoahUpdateRefsForOopClosure: public BasicOopIterateClosure {
+private:
+  ShenandoahHeap* _heap;
+  ShenandoahBarrierSet* _bs;
+
+  template <class T>
+  inline void do_oop_work(T* p) {
+    oop o;
+    if (STOREVAL_WRITE_BARRIER) {
+      o = _heap->evac_update_with_forwarded(p);
+      if (!CompressedOops::is_null(o)) {
+        _bs->enqueue(o);
+      }
+    } else {
+      _heap->maybe_update_with_forwarded(p);
+    }
+  }
+public:
+  ShenandoahUpdateRefsForOopClosure() : _heap(ShenandoahHeap::heap()), _bs(ShenandoahBarrierSet::barrier_set()) {
+    assert(UseShenandoahGC && ShenandoahCloneBarrier, "should be enabled");
+  }
+
+  virtual void do_oop(oop* p)       { do_oop_work(p); }
+  virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+};
+
+ShenandoahBarrierSet::ShenandoahBarrierSet(ShenandoahHeap* heap) :
+  BarrierSet(make_barrier_set_assembler<ShenandoahBarrierSetAssembler>(),
+             make_barrier_set_c1<ShenandoahBarrierSetC1>(),
+             make_barrier_set_c2<ShenandoahBarrierSetC2>(),
+             NULL /* barrier_set_nmethod */,
+             BarrierSet::FakeRtti(BarrierSet::ShenandoahBarrierSet)),
+  _heap(heap),
+  _satb_mark_queue_set()
+{
+}
+
+ShenandoahBarrierSetAssembler* ShenandoahBarrierSet::assembler() {
+  BarrierSetAssembler* const bsa = BarrierSet::barrier_set()->barrier_set_assembler();
+  return reinterpret_cast<ShenandoahBarrierSetAssembler*>(bsa);
+}
+
+void ShenandoahBarrierSet::print_on(outputStream* st) const {
+  st->print("ShenandoahBarrierSet");
+}
+
+bool ShenandoahBarrierSet::is_a(BarrierSet::Name bsn) {
+  return bsn == BarrierSet::ShenandoahBarrierSet;
+}
+
+bool ShenandoahBarrierSet::is_aligned(HeapWord* hw) {
+  return true;
+}
+
+template <class T, bool STOREVAL_WRITE_BARRIER>
+void ShenandoahBarrierSet::write_ref_array_loop(HeapWord* start, size_t count) {
+  assert(UseShenandoahGC && ShenandoahCloneBarrier, "should be enabled");
+  ShenandoahUpdateRefsForOopClosure<STOREVAL_WRITE_BARRIER> cl;
+  T* dst = (T*) start;
+  for (size_t i = 0; i < count; i++) {
+    cl.do_oop(dst++);
+  }
+}
+
+void ShenandoahBarrierSet::write_ref_array(HeapWord* start, size_t count) {
+  assert(UseShenandoahGC, "should be enabled");
+  if (count == 0) return;
+  if (!ShenandoahCloneBarrier) return;
+
+  if (!need_update_refs_barrier()) return;
+
+  if (_heap->is_concurrent_traversal_in_progress()) {
+    ShenandoahEvacOOMScope oom_evac_scope;
+    if (UseCompressedOops) {
+      write_ref_array_loop<narrowOop, /* wb = */ true>(start, count);
+    } else {
+      write_ref_array_loop<oop,       /* wb = */ true>(start, count);
+    }
+  } else {
+    if (UseCompressedOops) {
+      write_ref_array_loop<narrowOop, /* wb = */ false>(start, count);
+    } else {
+      write_ref_array_loop<oop,       /* wb = */ false>(start, count);
+    }
+  }
+}
+
+template <class T>
+void ShenandoahBarrierSet::write_ref_array_pre_work(T* dst, size_t count) {
+  shenandoah_assert_not_in_cset_loc_except(dst, _heap->cancelled_gc());
+  if (ShenandoahSATBBarrier && _heap->is_concurrent_mark_in_progress()) {
+    T* elem_ptr = dst;
+    for (size_t i = 0; i < count; i++, elem_ptr++) {
+      T heap_oop = RawAccess<>::oop_load(elem_ptr);
+      if (!CompressedOops::is_null(heap_oop)) {
+        enqueue(CompressedOops::decode_not_null(heap_oop));
+      }
+    }
+  }
+}
+
+void ShenandoahBarrierSet::write_ref_array_pre(oop* dst, size_t count, bool dest_uninitialized) {
+  if (! dest_uninitialized) {
+    write_ref_array_pre_work(dst, count);
+  }
+}
+
+void ShenandoahBarrierSet::write_ref_array_pre(narrowOop* dst, size_t count, bool dest_uninitialized) {
+  if (! dest_uninitialized) {
+    write_ref_array_pre_work(dst, count);
+  }
+}
+
+template <class T>
+inline void ShenandoahBarrierSet::inline_write_ref_field_pre(T* field, oop new_val) {
+  shenandoah_assert_not_in_cset_loc_except(field, _heap->cancelled_gc());
+  if (_heap->is_concurrent_mark_in_progress()) {
+    T heap_oop = RawAccess<>::oop_load(field);
+    if (!CompressedOops::is_null(heap_oop)) {
+      enqueue(CompressedOops::decode(heap_oop));
+    }
+  }
+}
+
+// These are the more general virtual versions.
+void ShenandoahBarrierSet::write_ref_field_pre_work(oop* field, oop new_val) {
+  inline_write_ref_field_pre(field, new_val);
+}
+
+void ShenandoahBarrierSet::write_ref_field_pre_work(narrowOop* field, oop new_val) {
+  inline_write_ref_field_pre(field, new_val);
+}
+
+void ShenandoahBarrierSet::write_ref_field_pre_work(void* field, oop new_val) {
+  guarantee(false, "Not needed");
+}
+
+void ShenandoahBarrierSet::write_ref_field_work(void* v, oop o, bool release) {
+  shenandoah_assert_not_in_cset_loc_except(v, _heap->cancelled_gc());
+  shenandoah_assert_not_forwarded_except  (v, o, o == NULL || _heap->cancelled_gc() || !_heap->is_concurrent_mark_in_progress());
+  shenandoah_assert_not_in_cset_except    (v, o, o == NULL || _heap->cancelled_gc() || !_heap->is_concurrent_mark_in_progress());
+}
+
+void ShenandoahBarrierSet::write_region(MemRegion mr) {
+  assert(UseShenandoahGC, "should be enabled");
+  if (!ShenandoahCloneBarrier) return;
+  if (! need_update_refs_barrier()) return;
+
+  // This is called for cloning an object (see jvm.cpp) after the clone
+  // has been made. We are not interested in any 'previous value' because
+  // it would be NULL in any case. But we *are* interested in any oop*
+  // that potentially need to be updated.
+
+  oop obj = oop(mr.start());
+  shenandoah_assert_correct(NULL, obj);
+  if (_heap->is_concurrent_traversal_in_progress()) {
+    ShenandoahEvacOOMScope oom_evac_scope;
+    ShenandoahUpdateRefsForOopClosure</* wb = */ true> cl;
+    obj->oop_iterate(&cl);
+  } else {
+    ShenandoahUpdateRefsForOopClosure</* wb = */ false> cl;
+    obj->oop_iterate(&cl);
+  }
+}
+
+oop ShenandoahBarrierSet::read_barrier(oop src) {
+  // Check for forwarded objects, because on Full GC path we might deal with
+  // non-trivial fwdptrs that contain Full GC specific metadata. We could check
+  // for is_full_gc_in_progress(), but this also covers the case of stable heap,
+  // which provides a bit of performance improvement.
+  if (ShenandoahReadBarrier && _heap->has_forwarded_objects()) {
+    return ShenandoahBarrierSet::resolve_forwarded(src);
+  } else {
+    return src;
+  }
+}
+
+bool ShenandoahBarrierSet::obj_equals(oop obj1, oop obj2) {
+  bool eq = oopDesc::equals_raw(obj1, obj2);
+  if (! eq && ShenandoahAcmpBarrier) {
+    OrderAccess::loadload();
+    obj1 = resolve_forwarded(obj1);
+    obj2 = resolve_forwarded(obj2);
+    eq = oopDesc::equals_raw(obj1, obj2);
+  }
+  return eq;
+}
+
+oop ShenandoahBarrierSet::write_barrier_mutator(oop obj) {
+  assert(UseShenandoahGC && ShenandoahWriteBarrier, "should be enabled");
+  assert(_heap->is_gc_in_progress_mask(ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL), "evac should be in progress");
+  shenandoah_assert_in_cset(NULL, obj);
+
+  oop fwd = resolve_forwarded_not_null(obj);
+  if (oopDesc::equals_raw(obj, fwd)) {
+    ShenandoahEvacOOMScope oom_evac_scope;
+
+    Thread* thread = Thread::current();
+    oop res_oop = _heap->evacuate_object(obj, thread);
+
+    // Since we are already here and paid the price of getting through runtime call adapters
+    // and acquiring oom-scope, it makes sense to try and evacuate more adjacent objects,
+    // thus amortizing the overhead. For sparsely live heaps, scan costs easily dominate
+    // total assist costs, and can introduce a lot of evacuation latency. This is why we
+    // only scan for _nearest_ N objects, regardless if they are eligible for evac or not.
+    // The scan itself should also avoid touching the non-marked objects below TAMS, because
+    // their metadata (notably, klasses) may be incorrect already.
+
+    size_t max = ShenandoahEvacAssist;
+    if (max > 0) {
+      // Traversal is special: it uses incomplete marking context, because it coalesces evac with mark.
+      // Other code uses complete marking context, because evac happens after the mark.
+      ShenandoahMarkingContext* ctx = _heap->is_concurrent_traversal_in_progress() ?
+                                      _heap->marking_context() : _heap->complete_marking_context();
+
+      ShenandoahHeapRegion* r = _heap->heap_region_containing(obj);
+      assert(r->is_cset(), "sanity");
+
+      HeapWord* cur = (HeapWord*)obj + obj->size() + ShenandoahBrooksPointer::word_size();
+
+      size_t count = 0;
+      while ((cur < r->top()) && ctx->is_marked(oop(cur)) && (count++ < max)) {
+        oop cur_oop = oop(cur);
+        if (oopDesc::equals_raw(cur_oop, resolve_forwarded_not_null(cur_oop))) {
+          _heap->evacuate_object(cur_oop, thread);
+        }
+        cur = cur + cur_oop->size() + ShenandoahBrooksPointer::word_size();
+      }
+    }
+
+    return res_oop;
+  }
+  return fwd;
+}
+
+oop ShenandoahBarrierSet::write_barrier_impl(oop obj) {
+  assert(UseShenandoahGC && ShenandoahWriteBarrier, "should be enabled");
+  if (!CompressedOops::is_null(obj)) {
+    bool evac_in_progress = _heap->is_gc_in_progress_mask(ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL);
+    oop fwd = resolve_forwarded_not_null(obj);
+    if (evac_in_progress &&
+        _heap->in_collection_set(obj) &&
+        oopDesc::equals_raw(obj, fwd)) {
+      Thread *t = Thread::current();
+      if (t->is_GC_task_thread()) {
+        return _heap->evacuate_object(obj, t);
+      } else {
+        ShenandoahEvacOOMScope oom_evac_scope;
+        return _heap->evacuate_object(obj, t);
+      }
+    } else {
+      return fwd;
+    }
+  } else {
+    return obj;
+  }
+}
+
+oop ShenandoahBarrierSet::write_barrier(oop obj) {
+  if (ShenandoahWriteBarrier && _heap->has_forwarded_objects()) {
+    return write_barrier_impl(obj);
+  } else {
+    return obj;
+  }
+}
+
+oop ShenandoahBarrierSet::storeval_barrier(oop obj) {
+  if (ShenandoahStoreValEnqueueBarrier) {
+    if (!CompressedOops::is_null(obj)) {
+      obj = write_barrier(obj);
+      enqueue(obj);
+    }
+  }
+  if (ShenandoahStoreValReadBarrier) {
+    obj = resolve_forwarded(obj);
+  }
+  return obj;
+}
+
+void ShenandoahBarrierSet::keep_alive_barrier(oop obj) {
+  if (ShenandoahKeepAliveBarrier && _heap->is_concurrent_mark_in_progress()) {
+    enqueue(obj);
+  }
+}
+
+void ShenandoahBarrierSet::enqueue(oop obj) {
+  shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_traversal_in_progress());
+  if (!_satb_mark_queue_set.is_active()) return;
+
+  // Filter marked objects before hitting the SATB queues. The same predicate would
+  // be used by SATBMQ::filter to eliminate already marked objects downstream, but
+  // filtering here helps to avoid wasteful SATB queueing work to begin with.
+  if (!_heap->requires_marking(obj)) return;
+
+  Thread* thr = Thread::current();
+  if (thr->is_Java_thread()) {
+    ShenandoahThreadLocalData::satb_mark_queue(thr).enqueue(obj);
+  } else {
+    MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
+    _satb_mark_queue_set.shared_satb_queue()->enqueue(obj);
+  }
+}
+
+void ShenandoahBarrierSet::on_thread_create(Thread* thread) {
+  // Create thread local data
+  ShenandoahThreadLocalData::create(thread);
+}
+
+void ShenandoahBarrierSet::on_thread_destroy(Thread* thread) {
+  // Destroy thread local data
+  ShenandoahThreadLocalData::destroy(thread);
+}
+
+void ShenandoahBarrierSet::on_thread_attach(JavaThread* thread) {
+  assert(!SafepointSynchronize::is_at_safepoint(), "We should not be at a safepoint");
+  assert(!ShenandoahThreadLocalData::satb_mark_queue(thread).is_active(), "SATB queue should not be active");
+  assert(ShenandoahThreadLocalData::satb_mark_queue(thread).is_empty(), "SATB queue should be empty");
+  if (ShenandoahBarrierSet::satb_mark_queue_set().is_active()) {
+    ShenandoahThreadLocalData::satb_mark_queue(thread).set_active(true);
+  }
+  ShenandoahThreadLocalData::set_gc_state(thread, _heap->gc_state());
+  ShenandoahThreadLocalData::initialize_gclab(thread);
+}
+
+void ShenandoahBarrierSet::on_thread_detach(JavaThread* thread) {
+  ShenandoahThreadLocalData::satb_mark_queue(thread).flush();
+  PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
+  if (gclab != NULL) {
+    gclab->retire();
+  }
+}