--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/g1/heapRegion.cpp	Thu Jun 05 15:57:56 2008 -0700
@@ -0,0 +1,874 @@
+/*
+ * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_heapRegion.cpp.incl"
+
+HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
+                                 HeapRegion* hr, OopClosure* cl,
+                                 CardTableModRefBS::PrecisionStyle precision,
+                                 FilterKind fk) :
+  ContiguousSpaceDCTOC(hr, cl, precision, NULL),
+  _hr(hr), _fk(fk), _g1(g1)
+{}
+
+FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
+                                                   OopClosure* oc) :
+  _r_bottom(r->bottom()), _r_end(r->end()),
+  _oc(oc), _out_of_region(0)
+{}
+
+class VerifyLiveClosure: public OopClosure {
+  G1CollectedHeap* _g1h;
+  CardTableModRefBS* _bs;
+  oop _containing_obj;
+  bool _failures;
+  int _n_failures;
+public:
+  VerifyLiveClosure(G1CollectedHeap* g1h) :
+    _g1h(g1h), _bs(NULL), _containing_obj(NULL),
+    _failures(false), _n_failures(0)
+  {
+    BarrierSet* bs = _g1h->barrier_set();
+    if (bs->is_a(BarrierSet::CardTableModRef))
+      _bs = (CardTableModRefBS*)bs;
+  }
+
+  void set_containing_obj(oop obj) {
+    _containing_obj = obj;
+  }
+
+  bool failures() { return _failures; }
+  int n_failures() { return _n_failures; }
+
+  virtual void do_oop(narrowOop* p) {
+    guarantee(false, "NYI");
+  }
+
+  void do_oop(oop* p) {
+    assert(_containing_obj != NULL, "Precondition");
+    assert(!_g1h->is_obj_dead(_containing_obj), "Precondition");
+    oop obj = *p;
+    if (obj != NULL) {
+      bool failed = false;
+      if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead(obj)) {
+        if (!_failures) {
+          gclog_or_tty->print_cr("");
+          gclog_or_tty->print_cr("----------");
+        }
+        if (!_g1h->is_in_closed_subset(obj)) {
+          gclog_or_tty->print_cr("Field "PTR_FORMAT
+                        " of live obj "PTR_FORMAT
+                        " points to obj "PTR_FORMAT
+                        " not in the heap.",
+                        p, (void*) _containing_obj, (void*) obj);
+        } else {
+          gclog_or_tty->print_cr("Field "PTR_FORMAT
+                        " of live obj "PTR_FORMAT
+                        " points to dead obj "PTR_FORMAT".",
+                        p, (void*) _containing_obj, (void*) obj);
+        }
+        gclog_or_tty->print_cr("Live obj:");
+        _containing_obj->print_on(gclog_or_tty);
+        gclog_or_tty->print_cr("Bad referent:");
+        obj->print_on(gclog_or_tty);
+        gclog_or_tty->print_cr("----------");
+        _failures = true;
+        failed = true;
+        _n_failures++;
+      }
+
+      if (!_g1h->full_collection()) {
+        HeapRegion* from = _g1h->heap_region_containing(p);
+        HeapRegion* to   = _g1h->heap_region_containing(*p);
+        if (from != NULL && to != NULL &&
+            from != to &&
+            !to->popular() &&
+            !to->isHumongous()) {
+          jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
+          jbyte cv_field = *_bs->byte_for_const(p);
+          const jbyte dirty = CardTableModRefBS::dirty_card_val();
+
+          bool is_bad = !(from->is_young()
+                          || to->rem_set()->contains_reference(p)
+                          || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
+                              (_containing_obj->is_objArray() ?
+                                  cv_field == dirty
+                               : cv_obj == dirty || cv_field == dirty));
+          if (is_bad) {
+            if (!_failures) {
+              gclog_or_tty->print_cr("");
+              gclog_or_tty->print_cr("----------");
+            }
+            gclog_or_tty->print_cr("Missing rem set entry:");
+            gclog_or_tty->print_cr("Field "PTR_FORMAT
+                          " of obj "PTR_FORMAT
+                          ", in region %d ["PTR_FORMAT
+                          ", "PTR_FORMAT"),",
+                          p, (void*) _containing_obj,
+                          from->hrs_index(),
+                          from->bottom(),
+                          from->end());
+            _containing_obj->print_on(gclog_or_tty);
+            gclog_or_tty->print_cr("points to obj "PTR_FORMAT
+                          " in region %d ["PTR_FORMAT
+                          ", "PTR_FORMAT").",
+                          (void*) obj, to->hrs_index(),
+                          to->bottom(), to->end());
+            obj->print_on(gclog_or_tty);
+            gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
+                          cv_obj, cv_field);
+            gclog_or_tty->print_cr("----------");
+            _failures = true;
+            if (!failed) _n_failures++;
+          }
+        }
+      }
+    }
+  }
+};
+
+template<class ClosureType>
+HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
+                               HeapRegion* hr,
+                               HeapWord* cur, HeapWord* top) {
+  oop cur_oop = oop(cur);
+  int oop_size = cur_oop->size();
+  HeapWord* next_obj = cur + oop_size;
+  while (next_obj < top) {
+    // Keep filtering the remembered set.
+    if (!g1h->is_obj_dead(cur_oop, hr)) {
+      // Bottom lies entirely below top, so we can call the
+      // non-memRegion version of oop_iterate below.
+#ifndef PRODUCT
+      if (G1VerifyMarkingInEvac) {
+        VerifyLiveClosure vl_cl(g1h);
+        cur_oop->oop_iterate(&vl_cl);
+      }
+#endif
+      cur_oop->oop_iterate(cl);
+    }
+    cur = next_obj;
+    cur_oop = oop(cur);
+    oop_size = cur_oop->size();
+    next_obj = cur + oop_size;
+  }
+  return cur;
+}
+
+void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
+                                              HeapWord* bottom,
+                                              HeapWord* top,
+                                              OopClosure* cl) {
+  G1CollectedHeap* g1h = _g1;
+
+  int oop_size;
+
+  OopClosure* cl2 = cl;
+  FilterIntoCSClosure intoCSFilt(this, g1h, cl);
+  FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
+  switch (_fk) {
+  case IntoCSFilterKind:      cl2 = &intoCSFilt; break;
+  case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
+  }
+
+  // Start filtering what we add to the remembered set. If the object is
+  // not considered dead, either because it is marked (in the mark bitmap)
+  // or it was allocated after marking finished, then we add it. Otherwise
+  // we can safely ignore the object.
+  if (!g1h->is_obj_dead(oop(bottom), _hr)) {
+#ifndef PRODUCT
+    if (G1VerifyMarkingInEvac) {
+      VerifyLiveClosure vl_cl(g1h);
+      oop(bottom)->oop_iterate(&vl_cl, mr);
+    }
+#endif
+    oop_size = oop(bottom)->oop_iterate(cl2, mr);
+  } else {
+    oop_size = oop(bottom)->size();
+  }
+
+  bottom += oop_size;
+
+  if (bottom < top) {
+    // We replicate the loop below for several kinds of possible filters.
+    switch (_fk) {
+    case NoFilterKind:
+      bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
+      break;
+    case IntoCSFilterKind: {
+      FilterIntoCSClosure filt(this, g1h, cl);
+      bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
+      break;
+    }
+    case OutOfRegionFilterKind: {
+      FilterOutOfRegionClosure filt(_hr, cl);
+      bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
+      break;
+    }
+    default:
+      ShouldNotReachHere();
+    }
+
+    // Last object. Need to do dead-obj filtering here too.
+    if (!g1h->is_obj_dead(oop(bottom), _hr)) {
+#ifndef PRODUCT
+      if (G1VerifyMarkingInEvac) {
+        VerifyLiveClosure vl_cl(g1h);
+        oop(bottom)->oop_iterate(&vl_cl, mr);
+      }
+#endif
+      oop(bottom)->oop_iterate(cl2, mr);
+    }
+  }
+}
+
+void HeapRegion::reset_after_compaction() {
+  G1OffsetTableContigSpace::reset_after_compaction();
+  // After a compaction the mark bitmap is invalid, so we must
+  // treat all objects as being inside the unmarked area.
+  zero_marked_bytes();
+  init_top_at_mark_start();
+}
+
+
+
+DirtyCardToOopClosure*
+HeapRegion::new_dcto_closure(OopClosure* cl,
+                             CardTableModRefBS::PrecisionStyle precision,
+                             HeapRegionDCTOC::FilterKind fk) {
+  return new HeapRegionDCTOC(G1CollectedHeap::heap(),
+                             this, cl, precision, fk);
+}
+
+void HeapRegion::hr_clear(bool par, bool clear_space) {
+  _humongous = false;
+  _humongous_start = false;
+  _humongous_start_region = NULL;
+  _in_collection_set = false;
+  _is_gc_alloc_region = false;
+
+  // Age stuff (if parallel, this will be done separately, since it needs
+  // to be sequential).
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+
+  set_young_index_in_cset(-1);
+  uninstall_surv_rate_group();
+  set_young_type(NotYoung);
+
+  // In case it had been the start of a humongous sequence, reset its end.
+  set_end(_orig_end);
+
+  if (!par) {
+    // If this is parallel, this will be done later.
+    HeapRegionRemSet* hrrs = rem_set();
+    if (hrrs != NULL) hrrs->clear();
+    _claimed = 0;
+  }
+  zero_marked_bytes();
+  set_sort_index(-1);
+  if ((uintptr_t)bottom() >= (uintptr_t)g1h->popular_object_boundary())
+    set_popular(false);
+
+  _offsets.resize(HeapRegion::GrainWords);
+  init_top_at_mark_start();
+  if (clear_space) clear();
+}
+
+// <PREDICTION>
+void HeapRegion::calc_gc_efficiency() {
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+  _gc_efficiency = (double) garbage_bytes() /
+                            g1h->predict_region_elapsed_time_ms(this, false);
+}
+// </PREDICTION>
+
+void HeapRegion::set_startsHumongous() {
+  _humongous_start = true; _humongous = true;
+  _humongous_start_region = this;
+  assert(end() == _orig_end, "Should be normal before alloc.");
+}
+
+bool HeapRegion::claimHeapRegion(jint claimValue) {
+  jint current = _claimed;
+  if (current != claimValue) {
+    jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
+    if (res == current) {
+      return true;
+    }
+  }
+  return false;
+}
+
+HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
+  HeapWord* low = addr;
+  HeapWord* high = end();
+  while (low < high) {
+    size_t diff = pointer_delta(high, low);
+    // Must add one below to bias toward the high amount.  Otherwise, if
+  // "high" were at the desired value, and "low" were one less, we
+    // would not converge on "high".  This is not symmetric, because
+    // we set "high" to a block start, which might be the right one,
+    // which we don't do for "low".
+    HeapWord* middle = low + (diff+1)/2;
+    if (middle == high) return high;
+    HeapWord* mid_bs = block_start_careful(middle);
+    if (mid_bs < addr) {
+      low = middle;
+    } else {
+      high = mid_bs;
+    }
+  }
+  assert(low == high && low >= addr, "Didn't work.");
+  return low;
+}
+
+void HeapRegion::set_next_on_unclean_list(HeapRegion* r) {
+  assert(r == NULL || r->is_on_unclean_list(), "Malformed unclean list.");
+  _next_in_special_set = r;
+}
+
+void HeapRegion::set_on_unclean_list(bool b) {
+  _is_on_unclean_list = b;
+}
+
+void HeapRegion::initialize(MemRegion mr, bool clear_space) {
+  G1OffsetTableContigSpace::initialize(mr, false);
+  hr_clear(false/*par*/, clear_space);
+}
+#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
+#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
+#endif // _MSC_VER
+
+
+HeapRegion::
+HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
+                     MemRegion mr, bool is_zeroed)
+  : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed),
+    _next_fk(HeapRegionDCTOC::NoFilterKind),
+    _hrs_index(-1),
+    _humongous(false), _humongous_start(false), _humongous_start_region(NULL),
+    _in_collection_set(false), _is_gc_alloc_region(false),
+    _is_on_free_list(false), _is_on_unclean_list(false),
+    _next_in_special_set(NULL), _orig_end(NULL),
+    _claimed(0), _evacuation_failed(false),
+    _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1),
+    _popularity(NotPopular),
+    _young_type(NotYoung), _next_young_region(NULL),
+    _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
+    _rem_set(NULL), _zfs(NotZeroFilled)
+{
+  _orig_end = mr.end();
+  // Note that initialize() will set the start of the unmarked area of the
+  // region.
+  this->initialize(mr, !is_zeroed);
+
+  _rem_set =  new HeapRegionRemSet(sharedOffsetArray, this);
+
+  assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
+  // In case the region is allocated during a pause, note the top.
+  // We haven't done any counting on a brand new region.
+  _top_at_conc_mark_count = bottom();
+}
+
+class NextCompactionHeapRegionClosure: public HeapRegionClosure {
+  const HeapRegion* _target;
+  bool _target_seen;
+  HeapRegion* _last;
+  CompactibleSpace* _res;
+public:
+  NextCompactionHeapRegionClosure(const HeapRegion* target) :
+    _target(target), _target_seen(false), _res(NULL) {}
+  bool doHeapRegion(HeapRegion* cur) {
+    if (_target_seen) {
+      if (!cur->isHumongous()) {
+        _res = cur;
+        return true;
+      }
+    } else if (cur == _target) {
+      _target_seen = true;
+    }
+    return false;
+  }
+  CompactibleSpace* result() { return _res; }
+};
+
+CompactibleSpace* HeapRegion::next_compaction_space() const {
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+  // cast away const-ness
+  HeapRegion* r = (HeapRegion*) this;
+  NextCompactionHeapRegionClosure blk(r);
+  g1h->heap_region_iterate_from(r, &blk);
+  return blk.result();
+}
+
+void HeapRegion::set_continuesHumongous(HeapRegion* start) {
+  // The order is important here.
+  start->add_continuingHumongousRegion(this);
+  _humongous = true; _humongous_start = false;
+  _humongous_start_region = start;
+}
+
+void HeapRegion::add_continuingHumongousRegion(HeapRegion* cont) {
+  // Must join the blocks of the current H region seq with the block of the
+  // added region.
+  offsets()->join_blocks(bottom(), cont->bottom());
+  arrayOop obj = (arrayOop)(bottom());
+  obj->set_length((int) (obj->length() + cont->capacity()/jintSize));
+  set_end(cont->end());
+  set_top(cont->end());
+}
+
+void HeapRegion::save_marks() {
+  set_saved_mark();
+}
+
+void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) {
+  HeapWord* p = mr.start();
+  HeapWord* e = mr.end();
+  oop obj;
+  while (p < e) {
+    obj = oop(p);
+    p += obj->oop_iterate(cl);
+  }
+  assert(p == e, "bad memregion: doesn't end on obj boundary");
+}
+
+#define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
+void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
+  ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl);              \
+}
+SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
+
+
+void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) {
+  oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
+}
+
+#ifdef DEBUG
+HeapWord* HeapRegion::allocate(size_t size) {
+  jint state = zero_fill_state();
+  assert(!G1CollectedHeap::heap()->allocs_are_zero_filled() ||
+         zero_fill_is_allocated(),
+         "When ZF is on, only alloc in ZF'd regions");
+  return G1OffsetTableContigSpace::allocate(size);
+}
+#endif
+
+void HeapRegion::set_zero_fill_state_work(ZeroFillState zfs) {
+  assert(top() == bottom() || zfs == Allocated,
+         "Region must be empty, or we must be setting it to allocated.");
+  assert(ZF_mon->owned_by_self() ||
+         Universe::heap()->is_gc_active(),
+         "Must hold the lock or be a full GC to modify.");
+  _zfs = zfs;
+}
+
+void HeapRegion::set_zero_fill_complete() {
+  set_zero_fill_state_work(ZeroFilled);
+  if (ZF_mon->owned_by_self()) {
+    ZF_mon->notify_all();
+  }
+}
+
+
+void HeapRegion::ensure_zero_filled() {
+  MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
+  ensure_zero_filled_locked();
+}
+
+void HeapRegion::ensure_zero_filled_locked() {
+  assert(ZF_mon->owned_by_self(), "Precondition");
+  bool should_ignore_zf = SafepointSynchronize::is_at_safepoint();
+  assert(should_ignore_zf || Heap_lock->is_locked(),
+         "Either we're in a GC or we're allocating a region.");
+  switch (zero_fill_state()) {
+  case HeapRegion::NotZeroFilled:
+    set_zero_fill_in_progress(Thread::current());
+    {
+      ZF_mon->unlock();
+      Copy::fill_to_words(bottom(), capacity()/HeapWordSize);
+      ZF_mon->lock_without_safepoint_check();
+    }
+    // A trap.
+    guarantee(zero_fill_state() == HeapRegion::ZeroFilling
+              && zero_filler() == Thread::current(),
+              "AHA!  Tell Dave D if you see this...");
+    set_zero_fill_complete();
+    // gclog_or_tty->print_cr("Did sync ZF.");
+    ConcurrentZFThread::note_sync_zfs();
+    break;
+  case HeapRegion::ZeroFilling:
+    if (should_ignore_zf) {
+      // We can "break" the lock and take over the work.
+      Copy::fill_to_words(bottom(), capacity()/HeapWordSize);
+      set_zero_fill_complete();
+      ConcurrentZFThread::note_sync_zfs();
+      break;
+    } else {
+      ConcurrentZFThread::wait_for_ZF_completed(this);
+    }
+  case HeapRegion::ZeroFilled:
+    // Nothing to do.
+    break;
+  case HeapRegion::Allocated:
+    guarantee(false, "Should not call on allocated regions.");
+  }
+  assert(zero_fill_state() == HeapRegion::ZeroFilled, "Post");
+}
+
+HeapWord*
+HeapRegion::object_iterate_mem_careful(MemRegion mr,
+                                                 ObjectClosure* cl) {
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+  // We used to use "block_start_careful" here.  But we're actually happy
+  // to update the BOT while we do this...
+  HeapWord* cur = block_start(mr.start());
+  mr = mr.intersection(used_region());
+  if (mr.is_empty()) return NULL;
+  // Otherwise, find the obj that extends onto mr.start().
+
+  assert(cur <= mr.start()
+         && (oop(cur)->klass() == NULL ||
+             cur + oop(cur)->size() > mr.start()),
+         "postcondition of block_start");
+  oop obj;
+  while (cur < mr.end()) {
+    obj = oop(cur);
+    if (obj->klass() == NULL) {
+      // Ran into an unparseable point.
+      return cur;
+    } else if (!g1h->is_obj_dead(obj)) {
+      cl->do_object(obj);
+    }
+    if (cl->abort()) return cur;
+    // The check above must occur before the operation below, since an
+    // abort might invalidate the "size" operation.
+    cur += obj->size();
+  }
+  return NULL;
+}
+
+HeapWord*
+HeapRegion::
+oops_on_card_seq_iterate_careful(MemRegion mr,
+                                     FilterOutOfRegionClosure* cl) {
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+
+  // If we're within a stop-world GC, then we might look at a card in a
+  // GC alloc region that extends onto a GC LAB, which may not be
+  // parseable.  Stop such at the "saved_mark" of the region.
+  if (G1CollectedHeap::heap()->is_gc_active()) {
+    mr = mr.intersection(used_region_at_save_marks());
+  } else {
+    mr = mr.intersection(used_region());
+  }
+  if (mr.is_empty()) return NULL;
+  // Otherwise, find the obj that extends onto mr.start().
+
+  // We used to use "block_start_careful" here.  But we're actually happy
+  // to update the BOT while we do this...
+  HeapWord* cur = block_start(mr.start());
+  assert(cur <= mr.start(), "Postcondition");
+
+  while (cur <= mr.start()) {
+    if (oop(cur)->klass() == NULL) {
+      // Ran into an unparseable point.
+      return cur;
+    }
+    // Otherwise...
+    int sz = oop(cur)->size();
+    if (cur + sz > mr.start()) break;
+    // Otherwise, go on.
+    cur = cur + sz;
+  }
+  oop obj;
+  obj = oop(cur);
+  // If we finish this loop...
+  assert(cur <= mr.start()
+         && obj->klass() != NULL
+         && cur + obj->size() > mr.start(),
+         "Loop postcondition");
+  if (!g1h->is_obj_dead(obj)) {
+    obj->oop_iterate(cl, mr);
+  }
+
+  HeapWord* next;
+  while (cur < mr.end()) {
+    obj = oop(cur);
+    if (obj->klass() == NULL) {
+      // Ran into an unparseable point.
+      return cur;
+    };
+    // Otherwise:
+    next = (cur + obj->size());
+    if (!g1h->is_obj_dead(obj)) {
+      if (next < mr.end()) {
+        obj->oop_iterate(cl);
+      } else {
+        // this obj spans the boundary.  If it's an array, stop at the
+        // boundary.
+        if (obj->is_objArray()) {
+          obj->oop_iterate(cl, mr);
+        } else {
+          obj->oop_iterate(cl);
+        }
+      }
+    }
+    cur = next;
+  }
+  return NULL;
+}
+
+void HeapRegion::print() const { print_on(gclog_or_tty); }
+void HeapRegion::print_on(outputStream* st) const {
+  if (isHumongous()) {
+    if (startsHumongous())
+      st->print(" HS");
+    else
+      st->print(" HC");
+  } else {
+    st->print("   ");
+  }
+  if (in_collection_set())
+    st->print(" CS");
+  else if (is_gc_alloc_region())
+    st->print(" A ");
+  else
+    st->print("   ");
+  if (is_young())
+    st->print(is_scan_only() ? " SO" : (is_survivor() ? " SU" : " Y "));
+  else
+    st->print("   ");
+  if (is_empty())
+    st->print(" F");
+  else
+    st->print("  ");
+  st->print(" %d", _gc_time_stamp);
+  G1OffsetTableContigSpace::print_on(st);
+}
+
+#define OBJ_SAMPLE_INTERVAL 0
+#define BLOCK_SAMPLE_INTERVAL 100
+
+// This really ought to be commoned up into OffsetTableContigSpace somehow.
+// We would need a mechanism to make that code skip dead objects.
+
+void HeapRegion::verify(bool allow_dirty) const {
+  G1CollectedHeap* g1 = G1CollectedHeap::heap();
+  HeapWord* p = bottom();
+  HeapWord* prev_p = NULL;
+  int objs = 0;
+  int blocks = 0;
+  VerifyLiveClosure vl_cl(g1);
+  while (p < top()) {
+    size_t size = oop(p)->size();
+    if (blocks == BLOCK_SAMPLE_INTERVAL) {
+      guarantee(p == block_start_const(p + (size/2)),
+                "check offset computation");
+      blocks = 0;
+    } else {
+      blocks++;
+    }
+    if (objs == OBJ_SAMPLE_INTERVAL) {
+      oop obj = oop(p);
+      if (!g1->is_obj_dead(obj, this)) {
+        obj->verify();
+        vl_cl.set_containing_obj(obj);
+        obj->oop_iterate(&vl_cl);
+        if (G1MaxVerifyFailures >= 0
+            && vl_cl.n_failures() >= G1MaxVerifyFailures) break;
+      }
+      objs = 0;
+    } else {
+      objs++;
+    }
+    prev_p = p;
+    p += size;
+  }
+  HeapWord* rend = end();
+  HeapWord* rtop = top();
+  if (rtop < rend) {
+    guarantee(block_start_const(rtop + (rend - rtop) / 2) == rtop,
+              "check offset computation");
+  }
+  if (vl_cl.failures()) {
+    gclog_or_tty->print_cr("Heap:");
+    G1CollectedHeap::heap()->print();
+    gclog_or_tty->print_cr("");
+  }
+  if (G1VerifyConcMark &&
+      G1VerifyConcMarkPrintReachable &&
+      vl_cl.failures()) {
+    g1->concurrent_mark()->print_prev_bitmap_reachable();
+  }
+  guarantee(!vl_cl.failures(), "should not have had any failures");
+  guarantee(p == top(), "end of last object must match end of space");
+}
+
+// G1OffsetTableContigSpace code; copied from space.cpp.  Hope this can go
+// away eventually.
+
+void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space) {
+  // false ==> we'll do the clearing if there's clearing to be done.
+  ContiguousSpace::initialize(mr, false);
+  _offsets.zero_bottom_entry();
+  _offsets.initialize_threshold();
+  if (clear_space) clear();
+}
+
+void G1OffsetTableContigSpace::clear() {
+  ContiguousSpace::clear();
+  _offsets.zero_bottom_entry();
+  _offsets.initialize_threshold();
+}
+
+void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
+  Space::set_bottom(new_bottom);
+  _offsets.set_bottom(new_bottom);
+}
+
+void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
+  Space::set_end(new_end);
+  _offsets.resize(new_end - bottom());
+}
+
+void G1OffsetTableContigSpace::print() const {
+  print_short();
+  gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
+                INTPTR_FORMAT ", " INTPTR_FORMAT ")",
+                bottom(), top(), _offsets.threshold(), end());
+}
+
+HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
+  return _offsets.initialize_threshold();
+}
+
+HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
+                                                    HeapWord* end) {
+  _offsets.alloc_block(start, end);
+  return _offsets.threshold();
+}
+
+HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+  assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
+  if (_gc_time_stamp < g1h->get_gc_time_stamp())
+    return top();
+  else
+    return ContiguousSpace::saved_mark_word();
+}
+
+void G1OffsetTableContigSpace::set_saved_mark() {
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+  unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
+
+  if (_gc_time_stamp < curr_gc_time_stamp) {
+    // The order of these is important, as another thread might be
+    // about to start scanning this region. If it does so after
+    // set_saved_mark and before _gc_time_stamp = ..., then the latter
+    // will be false, and it will pick up top() as the high water mark
+    // of region. If it does so after _gc_time_stamp = ..., then it
+    // will pick up the right saved_mark_word() as the high water mark
+    // of the region. Either way, the behaviour will be correct.
+    ContiguousSpace::set_saved_mark();
+    OrderAccess::release_store_ptr((volatile intptr_t*) &_gc_time_stamp,
+                                   (intptr_t) curr_gc_time_stamp);
+  }
+}
+
+G1OffsetTableContigSpace::
+G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
+                         MemRegion mr, bool is_zeroed) :
+  _offsets(sharedOffsetArray, mr),
+  _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
+  _gc_time_stamp(0)
+{
+  _offsets.set_space(this);
+  initialize(mr, !is_zeroed);
+}
+
+size_t RegionList::length() {
+  size_t len = 0;
+  HeapRegion* cur = hd();
+  DEBUG_ONLY(HeapRegion* last = NULL);
+  while (cur != NULL) {
+    len++;
+    DEBUG_ONLY(last = cur);
+    cur = get_next(cur);
+  }
+  assert(last == tl(), "Invariant");
+  return len;
+}
+
+void RegionList::insert_before_head(HeapRegion* r) {
+  assert(well_formed(), "Inv");
+  set_next(r, hd());
+  _hd = r;
+  _sz++;
+  if (tl() == NULL) _tl = r;
+  assert(well_formed(), "Inv");
+}
+
+void RegionList::prepend_list(RegionList* new_list) {
+  assert(well_formed(), "Precondition");
+  assert(new_list->well_formed(), "Precondition");
+  HeapRegion* new_tl = new_list->tl();
+  if (new_tl != NULL) {
+    set_next(new_tl, hd());
+    _hd = new_list->hd();
+    _sz += new_list->sz();
+    if (tl() == NULL) _tl = new_list->tl();
+  } else {
+    assert(new_list->hd() == NULL && new_list->sz() == 0, "Inv");
+  }
+  assert(well_formed(), "Inv");
+}
+
+void RegionList::delete_after(HeapRegion* r) {
+  assert(well_formed(), "Precondition");
+  HeapRegion* next = get_next(r);
+  assert(r != NULL, "Precondition");
+  HeapRegion* next_tl = get_next(next);
+  set_next(r, next_tl);
+  dec_sz();
+  if (next == tl()) {
+    assert(next_tl == NULL, "Inv");
+    _tl = r;
+  }
+  assert(well_formed(), "Inv");
+}
+
+HeapRegion* RegionList::pop() {
+  assert(well_formed(), "Inv");
+  HeapRegion* res = hd();
+  if (res != NULL) {
+    _hd = get_next(res);
+    _sz--;
+    set_next(res, NULL);
+    if (sz() == 0) _tl = NULL;
+  }
+  assert(well_formed(), "Inv");
+  return res;
+}