--- a/hotspot/src/share/vm/gc/g1/g1AllocRegion.cpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/g1/g1AllocRegion.cpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2016, Oracle and/or its affiliates. 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
@@ -277,7 +277,7 @@
     // Determine how far we are from the next card boundary. If it is smaller than
     // the minimum object size we can allocate into, expand into the next card.
     HeapWord* top = cur->top();
-    HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetTable::N_bytes);
+    HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, BOTConstants::N_bytes);
 
     size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize);
 

--- a/hotspot/src/share/vm/gc/g1/g1BlockOffsetTable.cpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/g1/g1BlockOffsetTable.cpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. 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
@@ -53,14 +53,14 @@
 bool G1BlockOffsetTable::is_card_boundary(HeapWord* p) const {
   assert(p >= _reserved.start(), "just checking");
   size_t delta = pointer_delta(p, _reserved.start());
-  return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
+  return (delta & right_n_bits((int)BOTConstants::LogN_words)) == (size_t)NoBits;
 }
 
 #ifdef ASSERT
 void G1BlockOffsetTable::check_index(size_t index, const char* msg) const {
-  assert((index) < (_reserved.word_size() >> LogN_words),
+  assert((index) < (_reserved.word_size() >> BOTConstants::LogN_words),
          "%s - index: " SIZE_FORMAT ", _vs.committed_size: " SIZE_FORMAT,
-         msg, (index), (_reserved.word_size() >> LogN_words));
+         msg, (index), (_reserved.word_size() >> BOTConstants::LogN_words));
   assert(G1CollectedHeap::heap()->is_in_exact(address_for_index_raw(index)),
          "Index " SIZE_FORMAT " corresponding to " PTR_FORMAT
          " (%u) is not in committed area.",
@@ -128,7 +128,7 @@
   size_t start_card = _bot->index_for(start);
   size_t end_card = _bot->index_for(end-1);
   assert(start ==_bot->address_for_index(start_card), "Precondition");
-  assert(end ==_bot->address_for_index(end_card)+N_words, "Precondition");
+  assert(end ==_bot->address_for_index(end_card)+BOTConstants::N_words, "Precondition");
   set_remainder_to_point_to_start_incl(start_card, end_card); // closed interval
 }
 
@@ -140,16 +140,16 @@
     return;
   }
   assert(start_card > _bot->index_for(_space->bottom()), "Cannot be first card");
-  assert(_bot->offset_array(start_card-1) <= N_words,
+  assert(_bot->offset_array(start_card-1) <= BOTConstants::N_words,
          "Offset card has an unexpected value");
   size_t start_card_for_region = start_card;
   u_char offset = max_jubyte;
-  for (int i = 0; i < BlockOffsetArray::N_powers; i++) {
+  for (uint i = 0; i < BOTConstants::N_powers; i++) {
     // -1 so that the the card with the actual offset is counted.  Another -1
     // so that the reach ends in this region and not at the start
     // of the next.
-    size_t reach = start_card - 1 + (BlockOffsetArray::power_to_cards_back(i+1) - 1);
-    offset = N_words + i;
+    size_t reach = start_card - 1 + (BOTConstants::power_to_cards_back(i+1) - 1);
+    offset = BOTConstants::N_words + i;
     if (reach >= end_card) {
       _bot->set_offset_array(start_card_for_region, end_card, offset);
       start_card_for_region = reach + 1;
@@ -170,18 +170,18 @@
   if (end_card < start_card) {
     return;
   }
-  guarantee(_bot->offset_array(start_card) == N_words, "Wrong value in second card");
+  guarantee(_bot->offset_array(start_card) == BOTConstants::N_words, "Wrong value in second card");
   for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
     u_char entry = _bot->offset_array(c);
-    if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) {
-      guarantee(entry > N_words,
+    if (c - start_card > BOTConstants::power_to_cards_back(1)) {
+      guarantee(entry > BOTConstants::N_words,
                 "Should be in logarithmic region - "
                 "entry: %u, "
                 "_array->offset_array(c): %u, "
                 "N_words: %u",
-                (uint)entry, (uint)_bot->offset_array(c), (uint)N_words);
+                (uint)entry, (uint)_bot->offset_array(c), BOTConstants::N_words);
     }
-    size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
+    size_t backskip = BOTConstants::entry_to_cards_back(entry);
     size_t landing_card = c - backskip;
     guarantee(landing_card >= (start_card - 1), "Inv");
     if (landing_card >= start_card) {
@@ -192,10 +192,10 @@
     } else {
       guarantee(landing_card == start_card - 1, "Tautology");
       // Note that N_words is the maximum offset value
-      guarantee(_bot->offset_array(landing_card) <= N_words,
+      guarantee(_bot->offset_array(landing_card) <= BOTConstants::N_words,
                 "landing card offset: %u, "
                 "N_words: %u",
-                (uint)_bot->offset_array(landing_card), (uint)N_words);
+                (uint)_bot->offset_array(landing_card), (uint)BOTConstants::N_words);
     }
   }
 }
@@ -217,7 +217,7 @@
   // Calculate a consistent next boundary.  If "n" is not at the boundary
   // already, step to the boundary.
   HeapWord* next_boundary = _bot->address_for_index(n_index) +
-                            (n_index == next_index ? 0 : N_words);
+                            (n_index == next_index ? 0 : BOTConstants::N_words);
   assert(next_boundary <= _bot->_reserved.end(),
          "next_boundary is beyond the end of the covered region "
          " next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT,
@@ -257,13 +257,13 @@
          "phantom block");
   assert(blk_end > threshold, "should be past threshold");
   assert(blk_start <= threshold, "blk_start should be at or before threshold");
-  assert(pointer_delta(threshold, blk_start) <= N_words,
+  assert(pointer_delta(threshold, blk_start) <= BOTConstants::N_words,
          "offset should be <= BlockOffsetSharedArray::N");
   assert(G1CollectedHeap::heap()->is_in_reserved(blk_start),
          "reference must be into the heap");
   assert(G1CollectedHeap::heap()->is_in_reserved(blk_end-1),
          "limit must be within the heap");
-  assert(threshold == _bot->_reserved.start() + index*N_words,
+  assert(threshold == _bot->_reserved.start() + index*BOTConstants::N_words,
          "index must agree with threshold");
 
   DEBUG_ONLY(size_t orig_index = index;)
@@ -283,14 +283,14 @@
     HeapWord* rem_st  = _bot->address_for_index(index + 1);
     // Calculate rem_end this way because end_index
     // may be the last valid index in the covered region.
-    HeapWord* rem_end = _bot->address_for_index(end_index) +  N_words;
+    HeapWord* rem_end = _bot->address_for_index(end_index) + BOTConstants::N_words;
     set_remainder_to_point_to_start(rem_st, rem_end);
   }
 
   index = end_index + 1;
   // Calculate threshold_ this way because end_index
   // may be the last valid index in the covered region.
-  threshold = _bot->address_for_index(end_index) + N_words;
+  threshold = _bot->address_for_index(end_index) + BOTConstants::N_words;
   assert(threshold >= blk_end, "Incorrect offset threshold");
 
   // index_ and threshold_ updated here.
@@ -303,7 +303,7 @@
   size_t start_index = _bot->index_for(blk_start);
   HeapWord* boundary = _bot->address_for_index(start_index);
   assert((_bot->offset_array(orig_index) == 0 && blk_start == boundary) ||
-         (_bot->offset_array(orig_index) > 0 && _bot->offset_array(orig_index) <= N_words),
+         (_bot->offset_array(orig_index) > 0 && _bot->offset_array(orig_index) <= BOTConstants::N_words),
          "offset array should have been set - "
          "orig_index offset: %u, "
          "blk_start: " PTR_FORMAT ", "
@@ -313,12 +313,12 @@
   for (size_t j = orig_index + 1; j <= end_index; j++) {
     assert(_bot->offset_array(j) > 0 &&
            _bot->offset_array(j) <=
-             (u_char) (N_words+BlockOffsetArray::N_powers-1),
+             (u_char) (BOTConstants::N_words+BOTConstants::N_powers-1),
            "offset array should have been set - "
            "%u not > 0 OR %u not <= %u",
            (uint) _bot->offset_array(j),
            (uint) _bot->offset_array(j),
-           (uint) (N_words+BlockOffsetArray::N_powers-1));
+           (uint) (BOTConstants::N_words+BOTConstants::N_powers-1));
   }
 #endif
 }
@@ -330,7 +330,7 @@
 
   for (size_t current_card = start_card; current_card < end_card; current_card++) {
     u_char entry = _bot->offset_array(current_card);
-    if (entry < N_words) {
+    if (entry < BOTConstants::N_words) {
       // The entry should point to an object before the current card. Verify that
       // it is possible to walk from that object in to the current card by just
       // iterating over the objects following it.
@@ -348,7 +348,7 @@
       // Because we refine the BOT based on which cards are dirty there is not much we can verify here.
       // We need to make sure that we are going backwards and that we don't pass the start of the
       // corresponding heap region. But that is about all we can verify.
-      size_t backskip = BlockOffsetArray::entry_to_cards_back(entry);
+      size_t backskip = BOTConstants::entry_to_cards_back(entry);
       guarantee(backskip >= 1, "Must be going back at least one card.");
 
       size_t max_backskip = current_card - start_card;

--- a/hotspot/src/share/vm/gc/g1/g1BlockOffsetTable.hpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/g1/g1BlockOffsetTable.hpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. 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
@@ -26,6 +26,7 @@
 #define SHARE_VM_GC_G1_G1BLOCKOFFSETTABLE_HPP
 
 #include "gc/g1/g1RegionToSpaceMapper.hpp"
+#include "gc/shared/blockOffsetTable.hpp"
 #include "memory/memRegion.hpp"
 #include "memory/virtualspace.hpp"
 #include "utilities/globalDefinitions.hpp"
@@ -54,9 +55,9 @@
   u_char* _offset_array;          // byte array keeping backwards offsets
 
   void check_offset(size_t offset, const char* msg) const {
-    assert(offset <= N_words,
+    assert(offset <= BOTConstants::N_words,
            "%s - offset: " SIZE_FORMAT ", N_words: %u",
-           msg, offset, (uint)N_words);
+           msg, offset, BOTConstants::N_words);
   }
 
   // Bounds checking accessors:
@@ -82,22 +83,15 @@
   // Return the number of slots needed for an offset array
   // that covers mem_region_words words.
   static size_t compute_size(size_t mem_region_words) {
-    size_t number_of_slots = (mem_region_words / N_words);
+    size_t number_of_slots = (mem_region_words / BOTConstants::N_words);
     return ReservedSpace::allocation_align_size_up(number_of_slots);
   }
 
   // Returns how many bytes of the heap a single byte of the BOT corresponds to.
   static size_t heap_map_factor() {
-    return N_bytes;
+    return BOTConstants::N_bytes;
   }
 
-  enum SomePublicConstants {
-    LogN = 9,
-    LogN_words = LogN - LogHeapWordSize,
-    N_bytes = 1 << LogN,
-    N_words = 1 << LogN_words
-  };
-
   // Initialize the Block Offset Table to cover the memory region passed
   // in the heap parameter.
   G1BlockOffsetTable(MemRegion heap, G1RegionToSpaceMapper* storage);
@@ -111,7 +105,7 @@
   inline HeapWord* address_for_index(size_t index) const;
   // Variant of address_for_index that does not check the index for validity.
   inline HeapWord* address_for_index_raw(size_t index) const {
-    return _reserved.start() + (index << LogN_words);
+    return _reserved.start() + (index << BOTConstants::LogN_words);
   }
 };
 
@@ -119,11 +113,6 @@
   friend class G1BlockOffsetTable;
   friend class VMStructs;
 private:
-  enum SomePrivateConstants {
-    N_words = G1BlockOffsetTable::N_words,
-    LogN    = G1BlockOffsetTable::LogN
-  };
-
   // allocation boundary at which offset array must be updated
   HeapWord* _next_offset_threshold;
   size_t    _next_offset_index;      // index corresponding to that boundary

--- a/hotspot/src/share/vm/gc/g1/g1BlockOffsetTable.inline.hpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/g1/g1BlockOffsetTable.inline.hpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. 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
@@ -76,7 +76,7 @@
 
 // Variant of index_for that does not check the index for validity.
 inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const {
-  return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> LogN;
+  return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> BOTConstants::LogN;
 }
 
 inline size_t G1BlockOffsetTable::index_for(const void* p) const {
@@ -117,15 +117,15 @@
   HeapWord* q = _bot->address_for_index(index);
 
   uint offset = _bot->offset_array(index);  // Extend u_char to uint.
-  while (offset >= N_words) {
+  while (offset >= BOTConstants::N_words) {
     // The excess of the offset from N_words indicates a power of Base
     // to go back by.
-    size_t n_cards_back = BlockOffsetArray::entry_to_cards_back(offset);
-    q -= (N_words * n_cards_back);
+    size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
+    q -= (BOTConstants::N_words * n_cards_back);
     index -= n_cards_back;
     offset = _bot->offset_array(index);
   }
-  assert(offset < N_words, "offset too large");
+  assert(offset < BOTConstants::N_words, "offset too large");
   q -= offset;
   return q;
 }

--- a/hotspot/src/share/vm/gc/g1/g1RemSet.cpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/g1/g1RemSet.cpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. 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
@@ -109,7 +109,7 @@
 
   // Set the "from" region in the closure.
   _oc->set_region(r);
-  MemRegion card_region(_bot->address_for_index(index), G1BlockOffsetTable::N_words);
+  MemRegion card_region(_bot->address_for_index(index), BOTConstants::N_words);
   MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
   MemRegion mr = pre_gc_allocated.intersection(card_region);
   if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {

--- a/hotspot/src/share/vm/gc/g1/heapRegionSet.cpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/g1/heapRegionSet.cpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2016, Oracle and/or its affiliates. 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
@@ -389,7 +389,7 @@
                                          bot_rs.size(),
                                          os::vm_page_size(),
                                          HeapRegion::GrainBytes,
-                                         G1BlockOffsetTable::N_bytes,
+                                         BOTConstants::N_bytes,
                                          mtGC);
   G1BlockOffsetTable bot(heap, bot_storage);
   bot_storage->commit_regions(0, num_regions_in_test);

--- a/hotspot/src/share/vm/gc/shared/blockOffsetTable.cpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/shared/blockOffsetTable.cpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2016, Oracle and/or its affiliates. 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
@@ -87,7 +87,7 @@
 bool BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const {
   assert(p >= _reserved.start(), "just checking");
   size_t delta = pointer_delta(p, _reserved.start());
-  return (delta & right_n_bits(LogN_words)) == (size_t)NoBits;
+  return (delta & right_n_bits((int)BOTConstants::LogN_words)) == (size_t)NoBits;
 }
 
 
@@ -104,7 +104,7 @@
   set_init_to_zero(init_to_zero_);
   if (!init_to_zero_) {
     // initialize cards to point back to mr.start()
-    set_remainder_to_point_to_start(mr.start() + N_words, mr.end());
+    set_remainder_to_point_to_start(mr.start() + BOTConstants::N_words, mr.end());
     _array->set_offset_array(0, 0);  // set first card to 0
   }
 }
@@ -160,7 +160,7 @@
   size_t start_card = _array->index_for(start);
   size_t end_card = _array->index_for(end-1);
   assert(start ==_array->address_for_index(start_card), "Precondition");
-  assert(end ==_array->address_for_index(end_card)+N_words, "Precondition");
+  assert(end ==_array->address_for_index(end_card)+BOTConstants::N_words, "Precondition");
   set_remainder_to_point_to_start_incl(start_card, end_card, reducing); // closed interval
 }
 
@@ -176,16 +176,16 @@
     return;
   }
   assert(start_card > _array->index_for(_bottom), "Cannot be first card");
-  assert(_array->offset_array(start_card-1) <= N_words,
+  assert(_array->offset_array(start_card-1) <= BOTConstants::N_words,
     "Offset card has an unexpected value");
   size_t start_card_for_region = start_card;
   u_char offset = max_jubyte;
-  for (int i = 0; i < N_powers; i++) {
+  for (uint i = 0; i < BOTConstants::N_powers; i++) {
     // -1 so that the the card with the actual offset is counted.  Another -1
     // so that the reach ends in this region and not at the start
     // of the next.
-    size_t reach = start_card - 1 + (power_to_cards_back(i+1) - 1);
-    offset = N_words + i;
+    size_t reach = start_card - 1 + (BOTConstants::power_to_cards_back(i+1) - 1);
+    offset = BOTConstants::N_words + i;
     if (reach >= end_card) {
       _array->set_offset_array(start_card_for_region, end_card, offset, reducing);
       start_card_for_region = reach + 1;
@@ -206,15 +206,15 @@
   if (end_card < start_card) {
     return;
   }
-  guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card");
-  u_char last_entry = N_words;
+  guarantee(_array->offset_array(start_card) == BOTConstants::N_words, "Wrong value in second card");
+  u_char last_entry = BOTConstants::N_words;
   for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) {
     u_char entry = _array->offset_array(c);
     guarantee(entry >= last_entry, "Monotonicity");
-    if (c - start_card > power_to_cards_back(1)) {
-      guarantee(entry > N_words, "Should be in logarithmic region");
+    if (c - start_card > BOTConstants::power_to_cards_back(1)) {
+      guarantee(entry > BOTConstants::N_words, "Should be in logarithmic region");
     }
-    size_t backskip = entry_to_cards_back(entry);
+    size_t backskip = BOTConstants::entry_to_cards_back(entry);
     size_t landing_card = c - backskip;
     guarantee(landing_card >= (start_card - 1), "Inv");
     if (landing_card >= start_card) {
@@ -222,7 +222,7 @@
     } else {
       guarantee(landing_card == (start_card - 1), "Tautology");
       // Note that N_words is the maximum offset value
-      guarantee(_array->offset_array(landing_card) <= N_words, "Offset value");
+      guarantee(_array->offset_array(landing_card) <= BOTConstants::N_words, "Offset value");
     }
     last_entry = entry;  // remember for monotonicity test
   }
@@ -254,7 +254,7 @@
   uintptr_t start_ui = (uintptr_t)blk_start;
   // Calculate the last card boundary preceding end of blk
   intptr_t boundary_before_end = (intptr_t)end_ui;
-  clear_bits(boundary_before_end, right_n_bits(LogN));
+  clear_bits(boundary_before_end, right_n_bits((int)BOTConstants::LogN));
   if (start_ui <= (uintptr_t)boundary_before_end) {
     // blk starts at or crosses a boundary
     // Calculate index of card on which blk begins
@@ -267,7 +267,7 @@
     if (blk_start != boundary) {
       // blk starts strictly after boundary
       // adjust card boundary and start_index forward to next card
-      boundary += N_words;
+      boundary += BOTConstants::N_words;
       start_index++;
     }
     assert(start_index <= end_index, "monotonicity of index_for()");
@@ -284,8 +284,8 @@
         // We have finished marking the "offset card". We need to now
         // mark the subsequent cards that this blk spans.
         if (start_index < end_index) {
-          HeapWord* rem_st = _array->address_for_index(start_index) + N_words;
-          HeapWord* rem_end = _array->address_for_index(end_index) + N_words;
+          HeapWord* rem_st = _array->address_for_index(start_index) + BOTConstants::N_words;
+          HeapWord* rem_end = _array->address_for_index(end_index) + BOTConstants::N_words;
           set_remainder_to_point_to_start(rem_st, rem_end, reducing);
         }
         break;
@@ -450,8 +450,8 @@
         bool more = true;
         uint i = 1;
         // Fix the first power block with  back_by > num_pref_cards.
-        while (more && (i < N_powers)) {
-          size_t back_by = power_to_cards_back(i);
+        while (more && (i < BOTConstants::N_powers)) {
+          size_t back_by = BOTConstants::power_to_cards_back(i);
           size_t right_index = suff_index + back_by - 1;
           size_t left_index  = right_index - num_pref_cards + 1;
           if (right_index >= end_index - 1) { // last iteration
@@ -466,7 +466,7 @@
             // is non-null.
             if (left_index <= right_index) {
               _array->set_offset_array(left_index, right_index,
-                                     N_words + i - 1, true /* reducing */);
+                                       BOTConstants::N_words + i - 1, true /* reducing */);
             } else {
               more = false; // we are done
               assert((end_index - 1) == right_index, "Must be at the end.");
@@ -477,8 +477,8 @@
           i++;
         }
         // Fix the rest of the power blocks.
-        while (more && (i < N_powers)) {
-          size_t back_by = power_to_cards_back(i);
+        while (more && (i < BOTConstants::N_powers)) {
+          size_t back_by = BOTConstants::power_to_cards_back(i);
           size_t right_index = suff_index + back_by - 1;
           size_t left_index  = right_index - num_pref_cards + 1;
           if (right_index >= end_index - 1) { // last iteration
@@ -489,7 +489,7 @@
             more  = false;
           }
           assert(left_index <= right_index, "Error");
-          _array->set_offset_array(left_index, right_index, N_words + i - 1, true /* reducing */);
+          _array->set_offset_array(left_index, right_index, BOTConstants::N_words + i - 1, true /* reducing */);
           i++;
         }
       }
@@ -530,11 +530,11 @@
   HeapWord* q = _array->address_for_index(index);
 
   uint offset = _array->offset_array(index);    // Extend u_char to uint.
-  while (offset >= N_words) {
+  while (offset >= BOTConstants::N_words) {
     // The excess of the offset from N_words indicates a power of Base
     // to go back by.
-    size_t n_cards_back = entry_to_cards_back(offset);
-    q -= (N_words * n_cards_back);
+    size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
+    q -= (BOTConstants::N_words * n_cards_back);
     assert(q >= _sp->bottom(),
            "q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT,
            p2i(q), p2i(_sp->bottom()));
@@ -544,7 +544,7 @@
     index -= n_cards_back;
     offset = _array->offset_array(index);
   }
-  assert(offset < N_words, "offset too large");
+  assert(offset < BOTConstants::N_words, "offset too large");
   index--;
   q -= offset;
   assert(q >= _sp->bottom(),
@@ -599,14 +599,14 @@
   uint offset;
   do {
     offset = _array->offset_array(index);
-    if (offset < N_words) {
+    if (offset < BOTConstants::N_words) {
       q -= offset;
     } else {
-      size_t n_cards_back = entry_to_cards_back(offset);
-      q -= (n_cards_back * N_words);
+      size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
+      q -= (n_cards_back * BOTConstants::N_words);
       index -= n_cards_back;
     }
-  } while (offset >= N_words);
+  } while (offset >= BOTConstants::N_words);
   assert(q <= addr, "block start should be to left of arg");
   return q;
 }
@@ -668,22 +668,22 @@
   HeapWord* q = _array->address_for_index(index);
 
   uint offset = _array->offset_array(index);    // Extend u_char to uint.
-  while (offset > N_words) {
+  while (offset > BOTConstants::N_words) {
     // The excess of the offset from N_words indicates a power of Base
     // to go back by.
-    size_t n_cards_back = entry_to_cards_back(offset);
-    q -= (N_words * n_cards_back);
+    size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
+    q -= (BOTConstants::N_words * n_cards_back);
     assert(q >= _sp->bottom(), "Went below bottom!");
     index -= n_cards_back;
     offset = _array->offset_array(index);
   }
-  while (offset == N_words) {
+  while (offset == BOTConstants::N_words) {
     assert(q >= _sp->bottom(), "Went below bottom!");
-    q -= N_words;
+    q -= BOTConstants::N_words;
     index--;
     offset = _array->offset_array(index);
   }
-  assert(offset < N_words, "offset too large");
+  assert(offset < BOTConstants::N_words, "offset too large");
   q -= offset;
   HeapWord* n = q;
 
@@ -716,14 +716,14 @@
          "should be past threshold");
   assert(blk_start <= _next_offset_threshold,
          "blk_start should be at or before threshold");
-  assert(pointer_delta(_next_offset_threshold, blk_start) <= N_words,
+  assert(pointer_delta(_next_offset_threshold, blk_start) <= BOTConstants::N_words,
          "offset should be <= BlockOffsetSharedArray::N");
   assert(Universe::heap()->is_in_reserved(blk_start),
          "reference must be into the heap");
   assert(Universe::heap()->is_in_reserved(blk_end-1),
          "limit must be within the heap");
   assert(_next_offset_threshold ==
-         _array->_reserved.start() + _next_offset_index*N_words,
+         _array->_reserved.start() + _next_offset_index*BOTConstants::N_words,
          "index must agree with threshold");
 
   debug_only(size_t orig_next_offset_index = _next_offset_index;)
@@ -745,7 +745,7 @@
     HeapWord* rem_st  = _array->address_for_index(_next_offset_index + 1);
     // Calculate rem_end this way because end_index
     // may be the last valid index in the covered region.
-    HeapWord* rem_end = _array->address_for_index(end_index) +  N_words;
+    HeapWord* rem_end = _array->address_for_index(end_index) +  BOTConstants::N_words;
     set_remainder_to_point_to_start(rem_st, rem_end);
   }
 
@@ -753,7 +753,7 @@
   _next_offset_index = end_index + 1;
   // Calculate _next_offset_threshold this way because end_index
   // may be the last valid index in the covered region.
-  _next_offset_threshold = _array->address_for_index(end_index) + N_words;
+  _next_offset_threshold = _array->address_for_index(end_index) + BOTConstants::N_words;
   assert(_next_offset_threshold >= blk_end, "Incorrect offset threshold");
 
 #ifdef ASSERT
@@ -764,11 +764,11 @@
   assert((_array->offset_array(orig_next_offset_index) == 0 &&
           blk_start == boundary) ||
           (_array->offset_array(orig_next_offset_index) > 0 &&
-         _array->offset_array(orig_next_offset_index) <= N_words),
+         _array->offset_array(orig_next_offset_index) <= BOTConstants::N_words),
          "offset array should have been set");
   for (size_t j = orig_next_offset_index + 1; j <= end_index; j++) {
     assert(_array->offset_array(j) > 0 &&
-           _array->offset_array(j) <= (u_char) (N_words+N_powers-1),
+           _array->offset_array(j) <= (u_char) (BOTConstants::N_words+BOTConstants::N_powers-1),
            "offset array should have been set");
   }
 #endif

--- a/hotspot/src/share/vm/gc/shared/blockOffsetTable.hpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/shared/blockOffsetTable.hpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2016, Oracle and/or its affiliates. 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
@@ -46,6 +46,34 @@
 
 class ContiguousSpace;
 
+class BOTConstants : public AllStatic {
+public:
+  static const uint LogN = 9;
+  static const uint LogN_words = LogN - LogHeapWordSize;
+  static const uint N_bytes = 1 << LogN;
+  static const uint N_words = 1 << LogN_words;
+  // entries "e" of at least N_words mean "go back by Base^(e-N_words)."
+  // All entries are less than "N_words + N_powers".
+  static const uint LogBase = 4;
+  static const uint Base = (1 << LogBase);
+  static const uint N_powers = 14;
+
+  static size_t power_to_cards_back(uint i) {
+    return (size_t)1 << (LogBase * i);
+  }
+  static size_t power_to_words_back(uint i) {
+    return power_to_cards_back(i) * N_words;
+  }
+  static size_t entry_to_cards_back(u_char entry) {
+    assert(entry >= N_words, "Precondition");
+    return power_to_cards_back(entry - N_words);
+  }
+  static size_t entry_to_words_back(u_char entry) {
+    assert(entry >= N_words, "Precondition");
+    return power_to_words_back(entry - N_words);
+  }
+};
+
 //////////////////////////////////////////////////////////////////////////
 // The BlockOffsetTable "interface"
 //////////////////////////////////////////////////////////////////////////
@@ -109,13 +137,6 @@
   friend class VMStructs;
 
  private:
-  enum SomePrivateConstants {
-    LogN = 9,
-    LogN_words = LogN - LogHeapWordSize,
-    N_bytes = 1 << LogN,
-    N_words = 1 << LogN_words
-  };
-
   bool _init_to_zero;
 
   // The reserved region covered by the shared array.
@@ -163,7 +184,7 @@
     check_reducing_assertion(reducing);
     assert(index < _vs.committed_size(), "index out of range");
     assert(high >= low, "addresses out of order");
-    assert(pointer_delta(high, low) <= N_words, "offset too large");
+    assert(pointer_delta(high, low) <= BOTConstants::N_words, "offset too large");
     assert(!reducing || _offset_array[index] >=  (u_char)pointer_delta(high, low),
            "Not reducing");
     _offset_array[index] = (u_char)pointer_delta(high, low);
@@ -174,7 +195,7 @@
     assert(index_for(right - 1) < _vs.committed_size(),
            "right address out of range");
     assert(left  < right, "Heap addresses out of order");
-    size_t num_cards = pointer_delta(right, left) >> LogN_words;
+    size_t num_cards = pointer_delta(right, left) >> BOTConstants::LogN_words;
 
     fill_range(index_for(left), num_cards, offset);
   }
@@ -191,7 +212,7 @@
   void check_offset_array(size_t index, HeapWord* high, HeapWord* low) const {
     assert(index < _vs.committed_size(), "index out of range");
     assert(high >= low, "addresses out of order");
-    assert(pointer_delta(high, low) <= N_words, "offset too large");
+    assert(pointer_delta(high, low) <= BOTConstants::N_words, "offset too large");
     assert(_offset_array[index] == pointer_delta(high, low),
            "Wrong offset");
   }
@@ -206,7 +227,7 @@
   // to be reserved.
 
   size_t compute_size(size_t mem_region_words) {
-    size_t number_of_slots = (mem_region_words / N_words) + 1;
+    size_t number_of_slots = (mem_region_words / BOTConstants::N_words) + 1;
     return ReservedSpace::allocation_align_size_up(number_of_slots);
   }
 
@@ -248,7 +269,6 @@
 //////////////////////////////////////////////////////////////////////////
 class BlockOffsetArray: public BlockOffsetTable {
   friend class VMStructs;
-  friend class G1BlockOffsetTablePart; // temp. until we restructure and cleanup
  protected:
   // The following enums are used by do_block_internal() below
   enum Action {
@@ -258,31 +278,6 @@
                         // (see verify_single_block()).
   };
 
-  enum SomePrivateConstants {
-    N_words = BlockOffsetSharedArray::N_words,
-    LogN    = BlockOffsetSharedArray::LogN,
-    // entries "e" of at least N_words mean "go back by Base^(e-N_words)."
-    // All entries are less than "N_words + N_powers".
-    LogBase = 4,
-    Base = (1 << LogBase),
-    N_powers = 14
-  };
-
-  static size_t power_to_cards_back(uint i) {
-    return (size_t)1 << (LogBase * i);
-  }
-  static size_t power_to_words_back(uint i) {
-    return power_to_cards_back(i) * N_words;
-  }
-  static size_t entry_to_cards_back(u_char entry) {
-    assert(entry >= N_words, "Precondition");
-    return power_to_cards_back(entry - N_words);
-  }
-  static size_t entry_to_words_back(u_char entry) {
-    assert(entry >= N_words, "Precondition");
-    return power_to_words_back(entry - N_words);
-  }
-
   // The shared array, which is shared with other BlockOffsetArray's
   // corresponding to different spaces within a generation or span of
   // memory.
@@ -344,7 +339,7 @@
       assert(_array->is_card_boundary(new_end),
              "new _end would not be a card boundary");
       // set all the newly added cards
-      _array->set_offset_array(_end, new_end, N_words);
+      _array->set_offset_array(_end, new_end, BOTConstants::N_words);
     }
     _end = new_end;  // update _end
   }

--- a/hotspot/src/share/vm/gc/shared/blockOffsetTable.inline.hpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/gc/shared/blockOffsetTable.inline.hpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2016, Oracle and/or its affiliates. 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
@@ -49,14 +49,14 @@
          pc <  (char*)_reserved.end(),
          "p not in range.");
   size_t delta = pointer_delta(pc, _reserved.start(), sizeof(char));
-  size_t result = delta >> LogN;
+  size_t result = delta >> BOTConstants::LogN;
   assert(result < _vs.committed_size(), "bad index from address");
   return result;
 }
 
 inline HeapWord* BlockOffsetSharedArray::address_for_index(size_t index) const {
   assert(index < _vs.committed_size(), "bad index");
-  HeapWord* result = _reserved.start() + (index << LogN_words);
+  HeapWord* result = _reserved.start() + (index << BOTConstants::LogN_words);
   assert(result >= _reserved.start() && result < _reserved.end(),
          "bad address from index");
   return result;

--- a/hotspot/src/share/vm/runtime/vmStructs.cpp	Sun Jan 10 20:02:50 2016 -0500
+++ b/hotspot/src/share/vm/runtime/vmStructs.cpp	Mon Jan 11 09:14:01 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2016, Oracle and/or its affiliates. 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
@@ -2320,12 +2320,13 @@
   declare_constant(BarrierSet::G1SATBCT)                                  \
   declare_constant(BarrierSet::G1SATBCTLogging)                           \
                                                                           \
-  declare_constant(BlockOffsetSharedArray::LogN)                          \
-  declare_constant(BlockOffsetSharedArray::LogN_words)                    \
-  declare_constant(BlockOffsetSharedArray::N_bytes)                       \
-  declare_constant(BlockOffsetSharedArray::N_words)                       \
-                                                                          \
-  declare_constant(BlockOffsetArray::N_words)                             \
+  declare_constant(BOTConstants::LogN)                                    \
+  declare_constant(BOTConstants::LogN_words)                              \
+  declare_constant(BOTConstants::N_bytes)                                 \
+  declare_constant(BOTConstants::N_words)                                 \
+  declare_constant(BOTConstants::LogBase)                                 \
+  declare_constant(BOTConstants::Base)                                    \
+  declare_constant(BOTConstants::N_powers)                                \
                                                                           \
   declare_constant(CardTableModRefBS::clean_card)                         \
   declare_constant(CardTableModRefBS::last_card)                          \