Fri, 17 May 2013 11:57:05 +0200
8014277: Remove ObjectClosure as base class for BoolObjectClosure
Reviewed-by: brutisso, tschatzl
1 /*
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP
28 #include "memory/memRegion.hpp"
29 #include "oops/oop.hpp"
30 #include "utilities/bitMap.hpp"
32 class ParMarkBitMapClosure;
33 class PSVirtualSpace;
35 class ParMarkBitMap: public CHeapObj<mtGC>
36 {
37 public:
38 typedef BitMap::idx_t idx_t;
40 // Values returned by the iterate() methods.
41 enum IterationStatus { incomplete, complete, full, would_overflow };
43 inline ParMarkBitMap();
44 bool initialize(MemRegion covered_region);
46 // Atomically mark an object as live.
47 bool mark_obj(HeapWord* addr, size_t size);
48 inline bool mark_obj(oop obj, int size);
50 // Return whether the specified begin or end bit is set.
51 inline bool is_obj_beg(idx_t bit) const;
52 inline bool is_obj_end(idx_t bit) const;
54 // Traditional interface for testing whether an object is marked or not (these
55 // test only the begin bits).
56 inline bool is_marked(idx_t bit) const;
57 inline bool is_marked(HeapWord* addr) const;
58 inline bool is_marked(oop obj) const;
60 inline bool is_unmarked(idx_t bit) const;
61 inline bool is_unmarked(HeapWord* addr) const;
62 inline bool is_unmarked(oop obj) const;
64 // Convert sizes from bits to HeapWords and back. An object that is n bits
65 // long will be bits_to_words(n) words long. An object that is m words long
66 // will take up words_to_bits(m) bits in the bitmap.
67 inline static size_t bits_to_words(idx_t bits);
68 inline static idx_t words_to_bits(size_t words);
70 // Return the size in words of an object given a begin bit and an end bit, or
71 // the equivalent beg_addr and end_addr.
72 inline size_t obj_size(idx_t beg_bit, idx_t end_bit) const;
73 inline size_t obj_size(HeapWord* beg_addr, HeapWord* end_addr) const;
75 // Return the size in words of the object (a search is done for the end bit).
76 inline size_t obj_size(idx_t beg_bit) const;
77 inline size_t obj_size(HeapWord* addr) const;
79 // Apply live_closure to each live object that lies completely within the
80 // range [live_range_beg, live_range_end). This is used to iterate over the
81 // compacted region of the heap. Return values:
82 //
83 // incomplete The iteration is not complete. The last object that
84 // begins in the range does not end in the range;
85 // closure->source() is set to the start of that object.
86 //
87 // complete The iteration is complete. All objects in the range
88 // were processed and the closure is not full;
89 // closure->source() is set one past the end of the range.
90 //
91 // full The closure is full; closure->source() is set to one
92 // past the end of the last object processed.
93 //
94 // would_overflow The next object in the range would overflow the closure;
95 // closure->source() is set to the start of that object.
96 IterationStatus iterate(ParMarkBitMapClosure* live_closure,
97 idx_t range_beg, idx_t range_end) const;
98 inline IterationStatus iterate(ParMarkBitMapClosure* live_closure,
99 HeapWord* range_beg,
100 HeapWord* range_end) const;
102 // Apply live closure as above and additionally apply dead_closure to all dead
103 // space in the range [range_beg, dead_range_end). Note that dead_range_end
104 // must be >= range_end. This is used to iterate over the dense prefix.
105 //
106 // This method assumes that if the first bit in the range (range_beg) is not
107 // marked, then dead space begins at that point and the dead_closure is
108 // applied. Thus callers must ensure that range_beg is not in the middle of a
109 // live object.
110 IterationStatus iterate(ParMarkBitMapClosure* live_closure,
111 ParMarkBitMapClosure* dead_closure,
112 idx_t range_beg, idx_t range_end,
113 idx_t dead_range_end) const;
114 inline IterationStatus iterate(ParMarkBitMapClosure* live_closure,
115 ParMarkBitMapClosure* dead_closure,
116 HeapWord* range_beg,
117 HeapWord* range_end,
118 HeapWord* dead_range_end) const;
120 // Return the number of live words in the range [beg_addr, end_obj) due to
121 // objects that start in the range. If a live object extends onto the range,
122 // the caller must detect and account for any live words due to that object.
123 // If a live object extends beyond the end of the range, only the words within
124 // the range are included in the result. The end of the range must be a live object,
125 // which is the case when updating pointers. This allows a branch to be removed
126 // from inside the loop.
127 size_t live_words_in_range(HeapWord* beg_addr, oop end_obj) const;
129 inline HeapWord* region_start() const;
130 inline HeapWord* region_end() const;
131 inline size_t region_size() const;
132 inline size_t size() const;
134 // Convert a heap address to/from a bit index.
135 inline idx_t addr_to_bit(HeapWord* addr) const;
136 inline HeapWord* bit_to_addr(idx_t bit) const;
138 // Return the bit index of the first marked object that begins (or ends,
139 // respectively) in the range [beg, end). If no object is found, return end.
140 inline idx_t find_obj_beg(idx_t beg, idx_t end) const;
141 inline idx_t find_obj_end(idx_t beg, idx_t end) const;
143 inline HeapWord* find_obj_beg(HeapWord* beg, HeapWord* end) const;
144 inline HeapWord* find_obj_end(HeapWord* beg, HeapWord* end) const;
146 // Clear a range of bits or the entire bitmap (both begin and end bits are
147 // cleared).
148 inline void clear_range(idx_t beg, idx_t end);
150 // Return the number of bits required to represent the specified number of
151 // HeapWords, or the specified region.
152 static inline idx_t bits_required(size_t words);
153 static inline idx_t bits_required(MemRegion covered_region);
155 void print_on_error(outputStream* st) const {
156 st->print_cr("Marking Bits: (ParMarkBitMap*) " PTR_FORMAT, this);
157 _beg_bits.print_on_error(st, " Begin Bits: ");
158 _end_bits.print_on_error(st, " End Bits: ");
159 }
161 #ifdef ASSERT
162 void verify_clear() const;
163 inline void verify_bit(idx_t bit) const;
164 inline void verify_addr(HeapWord* addr) const;
165 #endif // #ifdef ASSERT
167 private:
168 // Each bit in the bitmap represents one unit of 'object granularity.' Objects
169 // are double-word aligned in 32-bit VMs, but not in 64-bit VMs, so the 32-bit
170 // granularity is 2, 64-bit is 1.
171 static inline size_t obj_granularity() { return size_t(MinObjAlignment); }
172 static inline int obj_granularity_shift() { return LogMinObjAlignment; }
174 HeapWord* _region_start;
175 size_t _region_size;
176 BitMap _beg_bits;
177 BitMap _end_bits;
178 PSVirtualSpace* _virtual_space;
179 };
181 inline ParMarkBitMap::ParMarkBitMap():
182 _beg_bits(), _end_bits(), _region_start(NULL), _region_size(0), _virtual_space(NULL)
183 { }
185 inline void ParMarkBitMap::clear_range(idx_t beg, idx_t end)
186 {
187 _beg_bits.clear_range(beg, end);
188 _end_bits.clear_range(beg, end);
189 }
191 inline ParMarkBitMap::idx_t
192 ParMarkBitMap::bits_required(size_t words)
193 {
194 // Need two bits (one begin bit, one end bit) for each unit of 'object
195 // granularity' in the heap.
196 return words_to_bits(words * 2);
197 }
199 inline ParMarkBitMap::idx_t
200 ParMarkBitMap::bits_required(MemRegion covered_region)
201 {
202 return bits_required(covered_region.word_size());
203 }
205 inline HeapWord*
206 ParMarkBitMap::region_start() const
207 {
208 return _region_start;
209 }
211 inline HeapWord*
212 ParMarkBitMap::region_end() const
213 {
214 return region_start() + region_size();
215 }
217 inline size_t
218 ParMarkBitMap::region_size() const
219 {
220 return _region_size;
221 }
223 inline size_t
224 ParMarkBitMap::size() const
225 {
226 return _beg_bits.size();
227 }
229 inline bool ParMarkBitMap::is_obj_beg(idx_t bit) const
230 {
231 return _beg_bits.at(bit);
232 }
234 inline bool ParMarkBitMap::is_obj_end(idx_t bit) const
235 {
236 return _end_bits.at(bit);
237 }
239 inline bool ParMarkBitMap::is_marked(idx_t bit) const
240 {
241 return is_obj_beg(bit);
242 }
244 inline bool ParMarkBitMap::is_marked(HeapWord* addr) const
245 {
246 return is_marked(addr_to_bit(addr));
247 }
249 inline bool ParMarkBitMap::is_marked(oop obj) const
250 {
251 return is_marked((HeapWord*)obj);
252 }
254 inline bool ParMarkBitMap::is_unmarked(idx_t bit) const
255 {
256 return !is_marked(bit);
257 }
259 inline bool ParMarkBitMap::is_unmarked(HeapWord* addr) const
260 {
261 return !is_marked(addr);
262 }
264 inline bool ParMarkBitMap::is_unmarked(oop obj) const
265 {
266 return !is_marked(obj);
267 }
269 inline size_t
270 ParMarkBitMap::bits_to_words(idx_t bits)
271 {
272 return bits << obj_granularity_shift();
273 }
275 inline ParMarkBitMap::idx_t
276 ParMarkBitMap::words_to_bits(size_t words)
277 {
278 return words >> obj_granularity_shift();
279 }
281 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit, idx_t end_bit) const
282 {
283 DEBUG_ONLY(verify_bit(beg_bit);)
284 DEBUG_ONLY(verify_bit(end_bit);)
285 return bits_to_words(end_bit - beg_bit + 1);
286 }
288 inline size_t
289 ParMarkBitMap::obj_size(HeapWord* beg_addr, HeapWord* end_addr) const
290 {
291 DEBUG_ONLY(verify_addr(beg_addr);)
292 DEBUG_ONLY(verify_addr(end_addr);)
293 return pointer_delta(end_addr, beg_addr) + obj_granularity();
294 }
296 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit) const
297 {
298 const idx_t end_bit = _end_bits.get_next_one_offset_inline(beg_bit, size());
299 assert(is_marked(beg_bit), "obj not marked");
300 assert(end_bit < size(), "end bit missing");
301 return obj_size(beg_bit, end_bit);
302 }
304 inline size_t ParMarkBitMap::obj_size(HeapWord* addr) const
305 {
306 return obj_size(addr_to_bit(addr));
307 }
309 inline ParMarkBitMap::IterationStatus
310 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
311 HeapWord* range_beg,
312 HeapWord* range_end) const
313 {
314 return iterate(live_closure, addr_to_bit(range_beg), addr_to_bit(range_end));
315 }
317 inline ParMarkBitMap::IterationStatus
318 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
319 ParMarkBitMapClosure* dead_closure,
320 HeapWord* range_beg,
321 HeapWord* range_end,
322 HeapWord* dead_range_end) const
323 {
324 return iterate(live_closure, dead_closure,
325 addr_to_bit(range_beg), addr_to_bit(range_end),
326 addr_to_bit(dead_range_end));
327 }
329 inline bool
330 ParMarkBitMap::mark_obj(oop obj, int size)
331 {
332 return mark_obj((HeapWord*)obj, (size_t)size);
333 }
335 inline BitMap::idx_t
336 ParMarkBitMap::addr_to_bit(HeapWord* addr) const
337 {
338 DEBUG_ONLY(verify_addr(addr);)
339 return words_to_bits(pointer_delta(addr, region_start()));
340 }
342 inline HeapWord*
343 ParMarkBitMap::bit_to_addr(idx_t bit) const
344 {
345 DEBUG_ONLY(verify_bit(bit);)
346 return region_start() + bits_to_words(bit);
347 }
349 inline ParMarkBitMap::idx_t
350 ParMarkBitMap::find_obj_beg(idx_t beg, idx_t end) const
351 {
352 return _beg_bits.get_next_one_offset_inline_aligned_right(beg, end);
353 }
355 inline ParMarkBitMap::idx_t
356 ParMarkBitMap::find_obj_end(idx_t beg, idx_t end) const
357 {
358 return _end_bits.get_next_one_offset_inline_aligned_right(beg, end);
359 }
361 inline HeapWord*
362 ParMarkBitMap::find_obj_beg(HeapWord* beg, HeapWord* end) const
363 {
364 const idx_t beg_bit = addr_to_bit(beg);
365 const idx_t end_bit = addr_to_bit(end);
366 const idx_t search_end = BitMap::word_align_up(end_bit);
367 const idx_t res_bit = MIN2(find_obj_beg(beg_bit, search_end), end_bit);
368 return bit_to_addr(res_bit);
369 }
371 inline HeapWord*
372 ParMarkBitMap::find_obj_end(HeapWord* beg, HeapWord* end) const
373 {
374 const idx_t beg_bit = addr_to_bit(beg);
375 const idx_t end_bit = addr_to_bit(end);
376 const idx_t search_end = BitMap::word_align_up(end_bit);
377 const idx_t res_bit = MIN2(find_obj_end(beg_bit, search_end), end_bit);
378 return bit_to_addr(res_bit);
379 }
381 #ifdef ASSERT
382 inline void ParMarkBitMap::verify_bit(idx_t bit) const {
383 // Allow one past the last valid bit; useful for loop bounds.
384 assert(bit <= _beg_bits.size(), "bit out of range");
385 }
387 inline void ParMarkBitMap::verify_addr(HeapWord* addr) const {
388 // Allow one past the last valid address; useful for loop bounds.
389 assert(addr >= region_start(),
390 err_msg("addr too small, addr: " PTR_FORMAT " region start: " PTR_FORMAT, addr, region_start()));
391 assert(addr <= region_end(),
392 err_msg("addr too big, addr: " PTR_FORMAT " region end: " PTR_FORMAT, addr, region_end()));
393 }
394 #endif // #ifdef ASSERT
396 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP