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 /*

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  * 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,

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  *

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 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP

 #include "memory/memRegion.hpp"

 #include "gc_implementation/parallelScavenge/psVirtualspace.hpp"

 #include "utilities/bitMap.inline.hpp"

 class oopDesc;

 class ParMarkBitMapClosure;

 class ParMarkBitMap: public CHeapObj

 {

 public:

   typedef BitMap::idx_t idx_t;

   // Values returned by the iterate() methods.

   enum IterationStatus { incomplete, complete, full, would_overflow };

   inline ParMarkBitMap();

   inline ParMarkBitMap(MemRegion covered_region);

   bool initialize(MemRegion covered_region);

   // Atomically mark an object as live.

   bool mark_obj(HeapWord* addr, size_t size);

   inline bool mark_obj(oop obj, int size);

   inline bool mark_obj(oop obj);

   // Return whether the specified begin or end bit is set.

   inline bool is_obj_beg(idx_t bit) const;

   inline bool is_obj_end(idx_t bit) const;

   // Traditional interface for testing whether an object is marked or not (these

   // test only the begin bits).

   inline bool is_marked(idx_t bit)      const;

   inline bool is_marked(HeapWord* addr) const;

   inline bool is_marked(oop obj)        const;

   inline bool is_unmarked(idx_t bit)      const;

   inline bool is_unmarked(HeapWord* addr) const;

   inline bool is_unmarked(oop obj)        const;

   // Convert sizes from bits to HeapWords and back.  An object that is n bits

   // long will be bits_to_words(n) words long.  An object that is m words long

   // will take up words_to_bits(m) bits in the bitmap.

   inline static size_t bits_to_words(idx_t bits);

   inline static idx_t  words_to_bits(size_t words);

   // Return the size in words of an object given a begin bit and an end bit, or

   // the equivalent beg_addr and end_addr.

   inline size_t obj_size(idx_t beg_bit, idx_t end_bit) const;

   inline size_t obj_size(HeapWord* beg_addr, HeapWord* end_addr) const;

   // Return the size in words of the object (a search is done for the end bit).

   inline size_t obj_size(idx_t beg_bit)  const;

   inline size_t obj_size(HeapWord* addr) const;

   inline size_t obj_size(oop obj)        const;

   // Synonyms for the above.

   size_t obj_size_in_words(oop obj) const { return obj_size((HeapWord*)obj); }

   size_t obj_size_in_words(HeapWord* addr) const { return obj_size(addr); }

   // Apply live_closure to each live object that lies completely within the

   // range [live_range_beg, live_range_end).  This is used to iterate over the

   // compacted region of the heap.  Return values:

   //

   // incomplete         The iteration is not complete.  The last object that

   //                    begins in the range does not end in the range;

   //                    closure->source() is set to the start of that object.

   //

   // complete           The iteration is complete.  All objects in the range

   //                    were processed and the closure is not full;

   //                    closure->source() is set one past the end of the range.

   //

   // full               The closure is full; closure->source() is set to one

   //                    past the end of the last object processed.

   //

   // would_overflow     The next object in the range would overflow the closure;

   //                    closure->source() is set to the start of that object.

   IterationStatus iterate(ParMarkBitMapClosure* live_closure,

                           idx_t range_beg, idx_t range_end) const;

   inline IterationStatus iterate(ParMarkBitMapClosure* live_closure,

                                  HeapWord* range_beg,

                                  HeapWord* range_end) const;

   // Apply live closure as above and additionally apply dead_closure to all dead

   // space in the range [range_beg, dead_range_end).  Note that dead_range_end

   // must be >= range_end.  This is used to iterate over the dense prefix.

   //

   // This method assumes that if the first bit in the range (range_beg) is not

   // marked, then dead space begins at that point and the dead_closure is

   // applied.  Thus callers must ensure that range_beg is not in the middle of a

   // live object.

   IterationStatus iterate(ParMarkBitMapClosure* live_closure,

                           ParMarkBitMapClosure* dead_closure,

                           idx_t range_beg, idx_t range_end,

                           idx_t dead_range_end) const;

   inline IterationStatus iterate(ParMarkBitMapClosure* live_closure,

                                  ParMarkBitMapClosure* dead_closure,

                                  HeapWord* range_beg,

                                  HeapWord* range_end,

                                  HeapWord* dead_range_end) const;

   // Return the number of live words in the range [beg_addr, end_addr) due to

   // objects that start in the range.  If a live object extends onto the range,

   // the caller must detect and account for any live words due to that object.

   // If a live object extends beyond the end of the range, only the words within

   // the range are included in the result.

   size_t live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const;

   // Same as the above, except the end of the range must be a live object, which

   // is the case when updating pointers.  This allows a branch to be removed

   // from inside the loop.

   size_t live_words_in_range(HeapWord* beg_addr, oop end_obj) const;

   inline HeapWord* region_start() const;

   inline HeapWord* region_end() const;

   inline size_t    region_size() const;

   inline size_t    size() const;

   // Convert a heap address to/from a bit index.

   inline idx_t     addr_to_bit(HeapWord* addr) const;

   inline HeapWord* bit_to_addr(idx_t bit) const;

   // Return the bit index of the first marked object that begins (or ends,

   // respectively) in the range [beg, end).  If no object is found, return end.

   inline idx_t find_obj_beg(idx_t beg, idx_t end) const;

   inline idx_t find_obj_end(idx_t beg, idx_t end) const;

   inline HeapWord* find_obj_beg(HeapWord* beg, HeapWord* end) const;

   inline HeapWord* find_obj_end(HeapWord* beg, HeapWord* end) const;

   // Clear a range of bits or the entire bitmap (both begin and end bits are

   // cleared).

   inline void clear_range(idx_t beg, idx_t end);

   inline void clear() { clear_range(0, size()); }

   // Return the number of bits required to represent the specified number of

   // HeapWords, or the specified region.

   static inline idx_t bits_required(size_t words);

   static inline idx_t bits_required(MemRegion covered_region);

   static inline idx_t words_required(MemRegion covered_region);

 #ifndef PRODUCT

   // CAS statistics.

   size_t cas_tries() { return _cas_tries; }

   size_t cas_retries() { return _cas_retries; }

   size_t cas_by_another() { return _cas_by_another; }

   void reset_counters();

 #endif  // #ifndef PRODUCT

 #ifdef  ASSERT

   void verify_clear() const;

   inline void verify_bit(idx_t bit) const;

   inline void verify_addr(HeapWord* addr) const;

 #endif  // #ifdef ASSERT

 private:

   // Each bit in the bitmap represents one unit of 'object granularity.' Objects

   // are double-word aligned in 32-bit VMs, but not in 64-bit VMs, so the 32-bit

   // granularity is 2, 64-bit is 1.

   static inline size_t obj_granularity() { return size_t(MinObjAlignment); }

   static inline int obj_granularity_shift() { return LogMinObjAlignment; }

   HeapWord*       _region_start;

   size_t          _region_size;

   BitMap          _beg_bits;

   BitMap          _end_bits;

   PSVirtualSpace* _virtual_space;

 #ifndef PRODUCT

   size_t _cas_tries;

   size_t _cas_retries;

   size_t _cas_by_another;

 #endif  // #ifndef PRODUCT

 };

 inline ParMarkBitMap::ParMarkBitMap():

   _beg_bits(),

   _end_bits()

 {

   _region_start = 0;

   _virtual_space = 0;

 }

 inline ParMarkBitMap::ParMarkBitMap(MemRegion covered_region):

   _beg_bits(),

   _end_bits()

 {

   initialize(covered_region);

 }

 inline void ParMarkBitMap::clear_range(idx_t beg, idx_t end)

 {

   _beg_bits.clear_range(beg, end);

   _end_bits.clear_range(beg, end);

 }

 inline ParMarkBitMap::idx_t

 ParMarkBitMap::bits_required(size_t words)

 {

   // Need two bits (one begin bit, one end bit) for each unit of 'object

   // granularity' in the heap.

   return words_to_bits(words * 2);

 }

 inline ParMarkBitMap::idx_t

 ParMarkBitMap::bits_required(MemRegion covered_region)

 {

   return bits_required(covered_region.word_size());

 }

 inline ParMarkBitMap::idx_t

 ParMarkBitMap::words_required(MemRegion covered_region)

 {

   return bits_required(covered_region) / BitsPerWord;

 }

 inline HeapWord*

 ParMarkBitMap::region_start() const

 {

   return _region_start;

 }

 inline HeapWord*

 ParMarkBitMap::region_end() const

 {

   return region_start() + region_size();

 }

 inline size_t

 ParMarkBitMap::region_size() const

 {

   return _region_size;

 }

 inline size_t

 ParMarkBitMap::size() const

 {

   return _beg_bits.size();

 }

 inline bool ParMarkBitMap::is_obj_beg(idx_t bit) const

 {

   return _beg_bits.at(bit);

 }

 inline bool ParMarkBitMap::is_obj_end(idx_t bit) const

 {

   return _end_bits.at(bit);

 }

 inline bool ParMarkBitMap::is_marked(idx_t bit) const

 {

   return is_obj_beg(bit);

 }

 inline bool ParMarkBitMap::is_marked(HeapWord* addr) const

 {

   return is_marked(addr_to_bit(addr));

 }

 inline bool ParMarkBitMap::is_marked(oop obj) const

 {

   return is_marked((HeapWord*)obj);

 }

 inline bool ParMarkBitMap::is_unmarked(idx_t bit) const

 {

   return !is_marked(bit);

 }

 inline bool ParMarkBitMap::is_unmarked(HeapWord* addr) const

 {

   return !is_marked(addr);

 }

 inline bool ParMarkBitMap::is_unmarked(oop obj) const

 {

   return !is_marked(obj);

 }

 inline size_t

 ParMarkBitMap::bits_to_words(idx_t bits)

 {

   return bits << obj_granularity_shift();

 }

 inline ParMarkBitMap::idx_t

 ParMarkBitMap::words_to_bits(size_t words)

 {

   return words >> obj_granularity_shift();

 }

 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit, idx_t end_bit) const

 {

   DEBUG_ONLY(verify_bit(beg_bit);)

   DEBUG_ONLY(verify_bit(end_bit);)

   return bits_to_words(end_bit - beg_bit + 1);

 }

 inline size_t

 ParMarkBitMap::obj_size(HeapWord* beg_addr, HeapWord* end_addr) const

 {

   DEBUG_ONLY(verify_addr(beg_addr);)

   DEBUG_ONLY(verify_addr(end_addr);)

   return pointer_delta(end_addr, beg_addr) + obj_granularity();

 }

 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit) const

 {

   const idx_t end_bit = _end_bits.get_next_one_offset_inline(beg_bit, size());

   assert(is_marked(beg_bit), "obj not marked");

   assert(end_bit < size(), "end bit missing");

   return obj_size(beg_bit, end_bit);

 }

 inline size_t ParMarkBitMap::obj_size(HeapWord* addr) const

 {

   return obj_size(addr_to_bit(addr));

 }

 inline size_t ParMarkBitMap::obj_size(oop obj) const

 {

   return obj_size((HeapWord*)obj);

 }

 inline ParMarkBitMap::IterationStatus

 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,

                        HeapWord* range_beg,

                        HeapWord* range_end) const

 {

   return iterate(live_closure, addr_to_bit(range_beg), addr_to_bit(range_end));

 }

 inline ParMarkBitMap::IterationStatus

 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,

                        ParMarkBitMapClosure* dead_closure,

                        HeapWord* range_beg,

                        HeapWord* range_end,

                        HeapWord* dead_range_end) const

 {

   return iterate(live_closure, dead_closure,

                  addr_to_bit(range_beg), addr_to_bit(range_end),

                  addr_to_bit(dead_range_end));

 }

 inline bool

 ParMarkBitMap::mark_obj(oop obj, int size)

 {

   return mark_obj((HeapWord*)obj, (size_t)size);

 }

 inline BitMap::idx_t

 ParMarkBitMap::addr_to_bit(HeapWord* addr) const

 {

   DEBUG_ONLY(verify_addr(addr);)

   return words_to_bits(pointer_delta(addr, region_start()));

 }

 inline HeapWord*

 ParMarkBitMap::bit_to_addr(idx_t bit) const

 {

   DEBUG_ONLY(verify_bit(bit);)

   return region_start() + bits_to_words(bit);

 }

 inline ParMarkBitMap::idx_t

 ParMarkBitMap::find_obj_beg(idx_t beg, idx_t end) const

 {

   return _beg_bits.get_next_one_offset_inline_aligned_right(beg, end);

 }

 inline ParMarkBitMap::idx_t

 ParMarkBitMap::find_obj_end(idx_t beg, idx_t end) const

 {

   return _end_bits.get_next_one_offset_inline_aligned_right(beg, end);

 }

 inline HeapWord*

 ParMarkBitMap::find_obj_beg(HeapWord* beg, HeapWord* end) const

 {

   const idx_t beg_bit = addr_to_bit(beg);

   const idx_t end_bit = addr_to_bit(end);

   const idx_t search_end = BitMap::word_align_up(end_bit);

   const idx_t res_bit = MIN2(find_obj_beg(beg_bit, search_end), end_bit);

   return bit_to_addr(res_bit);

 }

 inline HeapWord*

 ParMarkBitMap::find_obj_end(HeapWord* beg, HeapWord* end) const

 {

   const idx_t beg_bit = addr_to_bit(beg);

   const idx_t end_bit = addr_to_bit(end);

   const idx_t search_end = BitMap::word_align_up(end_bit);

   const idx_t res_bit = MIN2(find_obj_end(beg_bit, search_end), end_bit);

   return bit_to_addr(res_bit);

 }

 #ifdef  ASSERT

 inline void ParMarkBitMap::verify_bit(idx_t bit) const {

   // Allow one past the last valid bit; useful for loop bounds.

   assert(bit <= _beg_bits.size(), "bit out of range");

 }

 inline void ParMarkBitMap::verify_addr(HeapWord* addr) const {

   // Allow one past the last valid address; useful for loop bounds.

   assert(addr >= region_start(), "addr too small");

   assert(addr <= region_start() + region_size(), "addr too big");

 }

 #endif  // #ifdef ASSERT

 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP