void G1MarkSweep::mark_sweep_phase2() { // Now all live objects are marked, compute the new object addresses. // It is imperative that we traverse perm_gen LAST. If dead space is // allowed a range of dead object may get overwritten by a dead int // array. If perm_gen is not traversed last a klassOop may get // overwritten. This is fine since it is dead, but if the class has dead // instances we have to skip them, and in order to find their size we // need the klassOop! // // It is not required that we traverse spaces in the same order in // phase2, phase3 and phase4, but the ValidateMarkSweep live oops // tracking expects us to do so. See comment under phase4. G1CollectedHeap* g1h = G1CollectedHeap::heap(); Generation* pg = g1h->perm_gen(); EventMark m("2 compute new addresses"); TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); GenMarkSweep::trace("2"); FindFirstRegionClosure cl; g1h->heap_region_iterate(&cl); HeapRegion *r = cl.result(); CompactibleSpace* sp = r; if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) { sp = r->next_compaction_space(); } G1PrepareCompactClosure blk(sp); g1h->heap_region_iterate(&blk); CompactPoint perm_cp(pg, NULL, NULL); pg->prepare_for_compaction(&perm_cp); }