--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/shared/cmBitMap.cpp	Thu Dec 04 23:03:22 2014 +0100
@@ -0,0 +1,128 @@
+
+// Concurrent marking bit map wrapper
+
+#include "gc_implementation/shared/cmBitMap.inline.hpp"
+#include "utilities/bitMap.inline.hpp"
+
+CMBitMapRO::CMBitMapRO(int shifter) :
+  _bm(),
+  _shifter(shifter) {
+  _bmStartWord = 0;
+  _bmWordSize = 0;
+}
+
+HeapWord* CMBitMapRO::getNextMarkedWordAddress(const HeapWord* addr,
+                                               const HeapWord* limit) const {
+  // First we must round addr *up* to a possible object boundary.
+  addr = (HeapWord*)align_size_up((intptr_t)addr,
+                                  HeapWordSize << _shifter);
+  size_t addrOffset = heapWordToOffset(addr);
+  if (limit == NULL) {
+    limit = _bmStartWord + _bmWordSize;
+  }
+  size_t limitOffset = heapWordToOffset(limit);
+  size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset);
+  HeapWord* nextAddr = offsetToHeapWord(nextOffset);
+  assert(nextAddr >= addr, "get_next_one postcondition");
+  assert(nextAddr == limit || isMarked(nextAddr),
+         "get_next_one postcondition");
+  return nextAddr;
+}
+
+HeapWord* CMBitMapRO::getNextUnmarkedWordAddress(const HeapWord* addr,
+                                                 const HeapWord* limit) const {
+  size_t addrOffset = heapWordToOffset(addr);
+  if (limit == NULL) {
+    limit = _bmStartWord + _bmWordSize;
+  }
+  size_t limitOffset = heapWordToOffset(limit);
+  size_t nextOffset = _bm.get_next_zero_offset(addrOffset, limitOffset);
+  HeapWord* nextAddr = offsetToHeapWord(nextOffset);
+  assert(nextAddr >= addr, "get_next_one postcondition");
+  assert(nextAddr == limit || !isMarked(nextAddr),
+         "get_next_one postcondition");
+  return nextAddr;
+}
+
+int CMBitMapRO::heapWordDiffToOffsetDiff(size_t diff) const {
+  assert((diff & ((1 << _shifter) - 1)) == 0, "argument check");
+  return (int) (diff >> _shifter);
+}
+
+#ifndef PRODUCT
+bool CMBitMapRO::covers(MemRegion heap_rs) const {
+  // assert(_bm.map() == _virtual_space.low(), "map inconsistency");
+  assert(((size_t)_bm.size() * ((size_t)1 << _shifter)) == _bmWordSize,
+         "size inconsistency");
+  return _bmStartWord == (HeapWord*)(heap_rs.start()) &&
+         _bmWordSize  == heap_rs.word_size();
+}
+#endif
+
+void CMBitMapRO::print_on_error(outputStream* st, const char* prefix) const {
+  _bm.print_on_error(st, prefix);
+}
+
+size_t CMBitMap::compute_size(size_t heap_size) {
+  return heap_size / mark_distance();
+}
+
+size_t CMBitMap::mark_distance() {
+  return MinObjAlignmentInBytes * BitsPerByte;
+}
+
+void CMBitMap::initialize(MemRegion heap, MemRegion bitmap) {
+  _bmStartWord = heap.start();
+  _bmWordSize = heap.word_size();
+
+  _bm.set_map((BitMap::bm_word_t*) bitmap.start());
+  _bm.set_size(_bmWordSize >> _shifter);
+}
+
+void CMBitMap::clearAll() {
+  _bm.clear();
+}
+
+void CMBitMap::markRange(MemRegion mr) {
+  mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
+  assert(!mr.is_empty(), "unexpected empty region");
+  assert((offsetToHeapWord(heapWordToOffset(mr.end())) ==
+          ((HeapWord *) mr.end())),
+         "markRange memory region end is not card aligned");
+  // convert address range into offset range
+  _bm.at_put_range(heapWordToOffset(mr.start()),
+                   heapWordToOffset(mr.end()), true);
+}
+
+void CMBitMap::parMarkRange(MemRegion mr) {
+  mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
+  assert(!mr.is_empty(), "unexpected empty region");
+  assert((offsetToHeapWord(heapWordToOffset(mr.end())) ==
+          ((HeapWord *) mr.end())),
+         "markRange memory region end is not card aligned");
+  // convert address range into offset range
+  _bm.par_at_put_range(heapWordToOffset(mr.start()),
+                   heapWordToOffset(mr.end()), true);
+}
+
+void CMBitMap::clearRange(MemRegion mr) {
+  mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
+  assert(!mr.is_empty(), "unexpected empty region");
+  // convert address range into offset range
+  _bm.at_put_range(heapWordToOffset(mr.start()),
+                   heapWordToOffset(mr.end()), false);
+}
+
+MemRegion CMBitMap::getAndClearMarkedRegion(HeapWord* addr,
+                                            HeapWord* end_addr) {
+  HeapWord* start = getNextMarkedWordAddress(addr);
+  start = MIN2(start, end_addr);
+  HeapWord* end   = getNextUnmarkedWordAddress(start);
+  end = MIN2(end, end_addr);
+  assert(start <= end, "Consistency check");
+  MemRegion mr(start, end);
+  if (!mr.is_empty()) {
+    clearRange(mr);
+  }
+  return mr;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/shared/cmBitMap.hpp	Thu Dec 04 23:03:22 2014 +0100
@@ -0,0 +1,113 @@
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_CMBITMAP_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_SHARED_CMBITMAP_HPP
+
+#include "memory/memRegion.hpp"
+#include "oops/oop.inline.hpp"
+#include "utilities/bitMap.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// A generic CM bit map.  This is essentially a wrapper around the BitMap
+// class, with one bit per (1<<_shifter) HeapWords.
+
+class CMBitMapRO VALUE_OBJ_CLASS_SPEC {
+ protected:
+  HeapWord* _bmStartWord;      // base address of range covered by map
+  size_t    _bmWordSize;       // map size (in #HeapWords covered)
+  const int _shifter;          // map to char or bit
+  BitMap    _bm;               // the bit map itself
+
+ public:
+  // constructor
+  CMBitMapRO(int shifter);
+
+  enum { do_yield = true };
+
+  // inquiries
+  HeapWord* startWord()   const { return _bmStartWord; }
+  size_t    sizeInWords() const { return _bmWordSize;  }
+  // the following is one past the last word in space
+  HeapWord* endWord()     const { return _bmStartWord + _bmWordSize; }
+
+  // read marks
+
+  bool isMarked(HeapWord* addr) const {
+    assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
+           "outside underlying space?");
+    return _bm.at(heapWordToOffset(addr));
+  }
+
+  // iteration
+  inline bool iterate(BitMapClosure* cl, MemRegion mr);
+  inline bool iterate(BitMapClosure* cl);
+
+  // Return the address corresponding to the next marked bit at or after
+  // "addr", and before "limit", if "limit" is non-NULL.  If there is no
+  // such bit, returns "limit" if that is non-NULL, or else "endWord()".
+  HeapWord* getNextMarkedWordAddress(const HeapWord* addr,
+                                     const HeapWord* limit = NULL) const;
+  // Return the address corresponding to the next unmarked bit at or after
+  // "addr", and before "limit", if "limit" is non-NULL.  If there is no
+  // such bit, returns "limit" if that is non-NULL, or else "endWord()".
+  HeapWord* getNextUnmarkedWordAddress(const HeapWord* addr,
+                                       const HeapWord* limit = NULL) const;
+
+  // conversion utilities
+  HeapWord* offsetToHeapWord(size_t offset) const {
+    return _bmStartWord + (offset << _shifter);
+  }
+  size_t heapWordToOffset(const HeapWord* addr) const {
+    return pointer_delta(addr, _bmStartWord) >> _shifter;
+  }
+  int heapWordDiffToOffsetDiff(size_t diff) const;
+
+  // The argument addr should be the start address of a valid object
+  HeapWord* nextObject(HeapWord* addr) {
+    oop obj = (oop) addr;
+    HeapWord* res =  addr + obj->size();
+    assert(offsetToHeapWord(heapWordToOffset(res)) == res, "sanity");
+    return res;
+  }
+
+  void print_on_error(outputStream* st, const char* prefix) const;
+
+  // debugging
+  NOT_PRODUCT(bool covers(MemRegion rs) const;)
+};
+
+class CMBitMap : public CMBitMapRO {
+
+ public:
+  static size_t compute_size(size_t heap_size);
+  // Returns the amount of bytes on the heap between two marks in the bitmap.
+  static size_t mark_distance();
+
+  CMBitMap() : CMBitMapRO(LogMinObjAlignment) {}
+
+  // Initializes the underlying BitMap to cover the given area.
+  void initialize(MemRegion heap, MemRegion bitmap);
+
+  // Write marks.
+  inline void mark(HeapWord* addr);
+  inline void clear(HeapWord* addr);
+  inline bool parMark(HeapWord* addr);
+  inline bool parClear(HeapWord* addr);
+
+  void markRange(MemRegion mr);
+  void parMarkRange(MemRegion mr);
+  void clearRange(MemRegion mr);
+
+  // Starting at the bit corresponding to "addr" (inclusive), find the next
+  // "1" bit, if any.  This bit starts some run of consecutive "1"'s; find
+  // the end of this run (stopping at "end_addr").  Return the MemRegion
+  // covering from the start of the region corresponding to the first bit
+  // of the run to the end of the region corresponding to the last bit of
+  // the run.  If there is no "1" bit at or after "addr", return an empty
+  // MemRegion.
+  MemRegion getAndClearMarkedRegion(HeapWord* addr, HeapWord* end_addr);
+
+  // Clear the whole mark bitmap.
+  void clearAll();
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_CMBITMAP_HPP

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/shared/cmBitMap.inline.hpp	Thu Dec 04 23:03:22 2014 +0100
@@ -0,0 +1,65 @@
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_CMBITMAP_INLINE_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_SHARED_CMBITMAP_INLINE_HPP
+
+#include "gc_implementation/shared/cmBitMap.hpp"
+#include "utilities/bitMap.inline.hpp"
+
+inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) {
+  HeapWord* start_addr = MAX2(startWord(), mr.start());
+  HeapWord* end_addr = MIN2(endWord(), mr.end());
+
+  if (end_addr > start_addr) {
+    // Right-open interval [start-offset, end-offset).
+    BitMap::idx_t start_offset = heapWordToOffset(start_addr);
+    BitMap::idx_t end_offset = heapWordToOffset(end_addr);
+
+    start_offset = _bm.get_next_one_offset(start_offset, end_offset);
+    while (start_offset < end_offset) {
+      if (!cl->do_bit(start_offset)) {
+        return false;
+      }
+      HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr);
+      BitMap::idx_t next_offset = heapWordToOffset(next_addr);
+      start_offset = _bm.get_next_one_offset(next_offset, end_offset);
+    }
+  }
+  return true;
+}
+
+inline bool CMBitMapRO::iterate(BitMapClosure* cl) {
+  MemRegion mr(startWord(), sizeInWords());
+  return iterate(cl, mr);
+}
+
+#define check_mark(addr)                                                       \
+  assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize),      \
+         "outside underlying space?");                                         \
+  /* assert(G1CollectedHeap::heap()->is_in_exact(addr),                  \
+         err_msg("Trying to access not available bitmap "PTR_FORMAT            \
+                 " corresponding to "PTR_FORMAT" (%u)",                        \
+                 p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr))); */
+
+inline void CMBitMap::mark(HeapWord* addr) {
+  check_mark(addr);
+  _bm.set_bit(heapWordToOffset(addr));
+}
+
+inline void CMBitMap::clear(HeapWord* addr) {
+  check_mark(addr);
+  _bm.clear_bit(heapWordToOffset(addr));
+}
+
+inline bool CMBitMap::parMark(HeapWord* addr) {
+  check_mark(addr);
+  return _bm.par_set_bit(heapWordToOffset(addr));
+}
+
+inline bool CMBitMap::parClear(HeapWord* addr) {
+  check_mark(addr);
+  return _bm.par_clear_bit(heapWordToOffset(addr));
+}
+
+#undef check_mark
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_CMBITMAP_INLINE_HPP