vm/nursery_collector.cpp

   1 #include "master.hpp"
   2
   3 namespace factor {
   4
   5 struct nursery_copier : no_fixup {
   6   bump_allocator* nursery;
   7   aging_space* aging;
   8
   9   nursery_copier(bump_allocator* nursery, aging_space* aging)
  10       : nursery(nursery), aging(aging) { }
  11
  12   object* fixup_data(object* obj) {
  13     if (!nursery->contains_p(obj)) {
  14       return obj;
  15     }
  16
  17     // The while-loop is a needed micro-optimization.
  18     while (obj->forwarding_pointer_p()) {
  19       obj = obj->forwarding_pointer();
  20     }
  21
  22     if (!nursery->contains_p(obj)) {
  23       return obj;
  24     }
  25
  26     cell size = obj->size();
  27     object* newpointer = aging->allot(size);
  28     if (!newpointer)
  29       throw must_start_gc_again();
  30
  31     memcpy(newpointer, obj, size);
  32     obj->forward_to(newpointer);
  33     return newpointer;
  34   }
  35 };
  36
  37 void factor_vm::collect_nursery() {
  38   // Copy live objects from the nursery (as determined by the root set and
  39   // marked cards in aging and tenured) to aging space.
  40   slot_visitor<nursery_copier>
  41       visitor(this, nursery_copier(data->nursery, data->aging));
  42
  43   cell scan = data->aging->start + data->aging->occupied_space();
  44
  45   visitor.visit_all_roots();
  46   gc_event* event = current_gc->event;
  47
  48   if (event)
  49     event->reset_timer();
  50   visitor.visit_cards(data->tenured, card_points_to_nursery,
  51                       card_points_to_nursery);
  52   visitor.visit_cards(data->aging, card_points_to_nursery, 0xff);
  53   if (event) {
  54     event->ended_phase(PHASE_CARD_SCAN);
  55     event->cards_scanned += visitor.cards_scanned;
  56     event->decks_scanned += visitor.decks_scanned;
  57   }
  58
  59   if (event)
  60     event->reset_timer();
  61   visitor.visit_code_heap_roots(&code->points_to_nursery);
  62   if (event) {
  63     event->ended_phase(PHASE_CODE_SCAN);
  64     event->code_blocks_scanned += code->points_to_nursery.size();
  65   }
  66
  67   visitor.cheneys_algorithm(data->aging, scan);
  68
  69   data->reset_nursery();
  70   code->points_to_nursery.clear();
  71 }
  72
  73 }