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#ifndef SHARE_VM_GC_PARALLEL_PARMARKBITMAP_HPP
#define SHARE_VM_GC_PARALLEL_PARMARKBITMAP_HPP
#include "memory/memRegion.hpp"
#include "oops/oop.hpp"
#include "utilities/bitMap.hpp"
class ParMarkBitMapClosure;
class PSVirtualSpace;
class ParCompactionManager;
class ParMarkBitMap: public CHeapObj<mtGC>
{
public:
typedef BitMap::idx_t idx_t;
// Values returned by the iterate() methods.
enum IterationStatus { incomplete, complete, full, would_overflow };
inline ParMarkBitMap();
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);
// 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;
// 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_obj) 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. 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(ParCompactionManager* cm, 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;
size_t reserved_byte_size() const { return _reserved_byte_size; }
// 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);
// 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);
void print_on_error(outputStream* st) const {
st->print_cr("Marking Bits: (ParMarkBitMap*) " PTR_FORMAT, p2i(this));
_beg_bits.print_on_error(st, " Begin Bits: ");
_end_bits.print_on_error(st, " End Bits: ");
}
#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:
size_t live_words_in_range_helper(HeapWord* beg_addr, oop end_obj) const;
bool is_live_words_in_range_in_cache(ParCompactionManager* cm, HeapWord* beg_addr) const;
size_t live_words_in_range_use_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const;
void update_live_words_in_range_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj, size_t result) const;
// 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;
BitMapView _beg_bits;
BitMapView _end_bits;
PSVirtualSpace* _virtual_space;
size_t _reserved_byte_size;
};
inline ParMarkBitMap::ParMarkBitMap():
_beg_bits(), _end_bits(), _region_start(NULL), _region_size(0), _virtual_space(NULL), _reserved_byte_size(0)
{ }
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 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 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, addr: " PTR_FORMAT " region start: " PTR_FORMAT, p2i(addr), p2i(region_start()));
assert(addr <= region_end(),
"addr too big, addr: " PTR_FORMAT " region end: " PTR_FORMAT, p2i(addr), p2i(region_end()));
}
#endif // #ifdef ASSERT
#endif // SHARE_VM_GC_PARALLEL_PARMARKBITMAP_HPP