235 size_t size = MarkSweep::adjust_pointers(oop(cur_obj));
236 size = space->adjust_obj_size(size);
237 debug_only(prev_obj = cur_obj);
238 cur_obj += size;
239 } else {
240 debug_only(prev_obj = cur_obj);
241 // cur_obj is not a live object, instead it points at the next live object
242 cur_obj = *(HeapWord**)cur_obj;
243 assert(cur_obj > prev_obj, "we should be moving forward through memory, cur_obj: " PTR_FORMAT ", prev_obj: " PTR_FORMAT, p2i(cur_obj), p2i(prev_obj));
244 }
245 }
246
247 assert(cur_obj == end_of_live, "just checking");
248 }
249
250 template <class SpaceType>
251 inline void CompactibleSpace::scan_and_compact(SpaceType* space) {
252 // Copy all live objects to their new location
253 // Used by MarkSweep::mark_sweep_phase4()
254
255 HeapWord* q = space->bottom();
256 HeapWord* const t = space->_end_of_live;
257 debug_only(HeapWord* prev_q = NULL);
258
259 if (q < t && space->_first_dead > q && !oop(q)->is_gc_marked()) {
260 #ifdef ASSERT // Debug only
261 // we have a chunk of the space which hasn't moved and we've reinitialized
262 // the mark word during the previous pass, so we can't use is_gc_marked for
263 // the traversal.
264 HeapWord* const end = space->_first_dead;
265
266 while (q < end) {
267 size_t size = space->obj_size(q);
268 assert(!oop(q)->is_gc_marked(), "should be unmarked (special dense prefix handling)");
269 prev_q = q;
270 q += size;
271 }
272 #endif
273
274 if (space->_first_dead == t) {
275 q = t;
276 } else {
277 // $$$ Funky
278 q = (HeapWord*) oop(space->_first_dead)->mark()->decode_pointer();
279 }
280 }
281
282 const intx scan_interval = PrefetchScanIntervalInBytes;
283 const intx copy_interval = PrefetchCopyIntervalInBytes;
284 while (q < t) {
285 if (!oop(q)->is_gc_marked()) {
286 // mark is pointer to next marked oop
287 debug_only(prev_q = q);
288 q = (HeapWord*) oop(q)->mark()->decode_pointer();
289 assert(q > prev_q, "we should be moving forward through memory");
290 } else {
291 // prefetch beyond q
292 Prefetch::read(q, scan_interval);
293
294 // size and destination
295 size_t size = space->obj_size(q);
296 HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee();
297
298 // prefetch beyond compaction_top
299 Prefetch::write(compaction_top, copy_interval);
300
301 // copy object and reinit its mark
302 assert(q != compaction_top, "everything in this pass should be moving");
303 Copy::aligned_conjoint_words(q, compaction_top, size);
304 oop(compaction_top)->init_mark();
305 assert(oop(compaction_top)->klass() != NULL, "should have a class");
306
307 debug_only(prev_q = q);
308 q += size;
309 }
310 }
311
312 // Let's remember if we were empty before we did the compaction.
313 bool was_empty = space->used_region().is_empty();
314 // Reset space after compaction is complete
315 space->reset_after_compaction();
316 // We do this clear, below, since it has overloaded meanings for some
317 // space subtypes. For example, OffsetTableContigSpace's that were
318 // compacted into will have had their offset table thresholds updated
319 // continuously, but those that weren't need to have their thresholds
320 // re-initialized. Also mangles unused area for debugging.
321 if (space->used_region().is_empty()) {
322 if (!was_empty) space->clear(SpaceDecorator::Mangle);
323 } else {
324 if (ZapUnusedHeapArea) space->mangle_unused_area();
325 }
326 }
327
328 size_t ContiguousSpace::scanned_block_size(const HeapWord* addr) const {
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235 size_t size = MarkSweep::adjust_pointers(oop(cur_obj));
236 size = space->adjust_obj_size(size);
237 debug_only(prev_obj = cur_obj);
238 cur_obj += size;
239 } else {
240 debug_only(prev_obj = cur_obj);
241 // cur_obj is not a live object, instead it points at the next live object
242 cur_obj = *(HeapWord**)cur_obj;
243 assert(cur_obj > prev_obj, "we should be moving forward through memory, cur_obj: " PTR_FORMAT ", prev_obj: " PTR_FORMAT, p2i(cur_obj), p2i(prev_obj));
244 }
245 }
246
247 assert(cur_obj == end_of_live, "just checking");
248 }
249
250 template <class SpaceType>
251 inline void CompactibleSpace::scan_and_compact(SpaceType* space) {
252 // Copy all live objects to their new location
253 // Used by MarkSweep::mark_sweep_phase4()
254
255 HeapWord* cur_obj = space->bottom();
256 HeapWord* const end_of_live = space->_end_of_live;
257 debug_only(HeapWord* prev_obj = NULL);
258
259 if (cur_obj < end_of_live && space->_first_dead > cur_obj && !oop(cur_obj)->is_gc_marked()) {
260 #ifdef ASSERT // Debug only
261 // we have a chunk of the space which hasn't moved and we've reinitialized
262 // the mark word during the previous pass, so we can't use is_gc_marked for
263 // the traversal.
264 HeapWord* const end = space->_first_dead;
265
266 while (cur_obj < end) {
267 size_t size = space->obj_size(cur_obj);
268 assert(!oop(cur_obj)->is_gc_marked(), "should be unmarked (special dense prefix handling)");
269 prev_obj = cur_obj;
270 cur_obj += size;
271 }
272 #endif
273
274 if (space->_first_dead == end_of_live) {
275 cur_obj = end_of_live;
276 } else {
277 // $$$ Funky
278 cur_obj = (HeapWord*) oop(space->_first_dead)->mark()->decode_pointer();
279 }
280 }
281
282 const intx scan_interval = PrefetchScanIntervalInBytes;
283 const intx copy_interval = PrefetchCopyIntervalInBytes;
284 while (cur_obj < end_of_live) {
285 if (!oop(cur_obj)->is_gc_marked()) {
286 // mark is pointer to next marked oop
287 debug_only(prev_obj = cur_obj);
288 cur_obj = (HeapWord*) oop(cur_obj)->mark()->decode_pointer();
289 assert(cur_obj > prev_obj, "we should be moving forward through memory");
290 } else {
291 // prefetch beyond q
292 Prefetch::read(cur_obj, scan_interval);
293
294 // size and destination
295 size_t size = space->obj_size(cur_obj);
296 HeapWord* compaction_top = (HeapWord*)oop(cur_obj)->forwardee();
297
298 // prefetch beyond compaction_top
299 Prefetch::write(compaction_top, copy_interval);
300
301 // copy object and reinit its mark
302 assert(cur_obj != compaction_top, "everything in this pass should be moving");
303 Copy::aligned_conjoint_words(cur_obj, compaction_top, size);
304 oop(compaction_top)->init_mark();
305 assert(oop(compaction_top)->klass() != NULL, "should have a class");
306
307 debug_only(prev_obj = cur_obj);
308 cur_obj += size;
309 }
310 }
311
312 // Let's remember if we were empty before we did the compaction.
313 bool was_empty = space->used_region().is_empty();
314 // Reset space after compaction is complete
315 space->reset_after_compaction();
316 // We do this clear, below, since it has overloaded meanings for some
317 // space subtypes. For example, OffsetTableContigSpace's that were
318 // compacted into will have had their offset table thresholds updated
319 // continuously, but those that weren't need to have their thresholds
320 // re-initialized. Also mangles unused area for debugging.
321 if (space->used_region().is_empty()) {
322 if (!was_empty) space->clear(SpaceDecorator::Mangle);
323 } else {
324 if (ZapUnusedHeapArea) space->mangle_unused_area();
325 }
326 }
327
328 size_t ContiguousSpace::scanned_block_size(const HeapWord* addr) const {
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