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_phase(PHASE_CARD_SCAN);
  56       event->cards_scanned += visitor.cards_scanned;
  57       event->decks_scanned += visitor.decks_scanned;
  58     }
  59
  60     if (event)
  61       event->reset_timer();
  62     visitor.visit_code_heap_roots(&code->points_to_aging);
  63     if (event) {
  64       event->ended_phase(PHASE_CODE_SCAN);
  65       event->code_blocks_scanned += code->points_to_aging.size();
  66     }
  67     visitor.visit_mark_stack(&mark_stack);
  68   }
  69   {
  70     // If collection fails here, do a to_tenured collection.
  71     current_gc->op = COLLECT_AGING_OP;
  72
  73     std::swap(data->aging, data->aging_semispace);
  74     data->reset_aging();
  75
  76     aging_space *aging = data->aging;
  77     slot_visitor<to_aging_copier>
  78         visitor(this, to_aging_copier(aging, data->tenured));
  79
  80     cell scan = aging->start + aging->occupied_space();
  81
  82     visitor.visit_all_roots();
  83     visitor.cheneys_algorithm(aging, scan);
  84
  85     data->reset_nursery();
  86     code->clear_remembered_set();
  87   }
  88 }
  89
  90 }