vm/aging_collector.cpp

   1 #include "master.hpp"
   2
   3 namespace factor {
   4
   5 struct to_aging_copier : no_fixup {
   6   aging_space* aging;
   7   tenured_space* tenured;
   8
   9   to_aging_copier(aging_space* aging, tenured_space* tenured)
  10       : aging(aging), tenured(tenured) { }
  11
  12   object* fixup_data(object* obj) {
  13     if (aging->contains_p(obj) || tenured->contains_p(obj)) {
  14       return obj;
  15     }
  16
  17     // Is there another forwarding pointer?
  18     while (obj->forwarding_pointer_p()) {
  19       object* dest = obj->forwarding_pointer();
  20       obj = dest;
  21     }
  22
  23     if (aging->contains_p(obj) || tenured->contains_p(obj)) {
  24       return obj;
  25     }
  26
  27     cell size = obj->size();
  28     object* newpointer = aging->allot(size);
  29     if (!newpointer)
  30       throw must_start_gc_again();
  31
  32     memcpy(newpointer, obj, size);
  33     obj->forward_to(newpointer);
  34
  35     return newpointer;
  36   }
  37 };
  38
  39 void factor_vm::collect_aging() {
  40   // Promote objects referenced from tenured space to tenured space, copy
  41   // everything else to the aging semi-space, and reset the nursery pointer.
  42   {
  43     // Change the op so that if we fail here, an assertion will be raised.
  44     current_gc->op = collect_to_tenured_op;
  45
  46     slot_visitor<from_tenured_refs_copier>
  47         visitor(this, from_tenured_refs_copier(data->tenured, &mark_stack));
  48
  49     gc_event* event = current_gc->event;
  50
  51     if (event)
  52       event->reset_timer();
  53     visitor.visit_cards(data->tenured, card_points_to_aging, 0xff);
  54     if (event)
  55       event->ended_card_scan(visitor.cards_scanned, visitor.decks_scanned);
  56
  57     if (event)
  58       event->reset_timer();
  59     visitor.visit_code_heap_roots(&code->points_to_aging);
  60     if (event)
  61       event->ended_code_scan(code->points_to_aging.size());
  62
  63     visitor.visit_mark_stack(&mark_stack);
  64   }
  65   {
  66     // If collection fails here, do a to_tenured collection.
  67     current_gc->op = collect_aging_op;
  68
  69     std::swap(data->aging, data->aging_semispace);
  70     data->reset_aging();
  71
  72     aging_space *aging = data->aging;
  73     slot_visitor<to_aging_copier>
  74         visitor(this, to_aging_copier(aging, data->tenured));
  75
  76     cell scan = aging->start + aging->occupied_space();
  77
  78     visitor.visit_all_roots();
  79     visitor.cheneys_algorithm(aging, scan);
  80
  81     data->reset_nursery();
  82     code->clear_remembered_set();
  83   }
  84 }
  85
  86 }