vm/full_collector.cpp

   1 #include "master.hpp"
   2
   3 namespace factor {
   4
   5 struct full_collection_copier : no_fixup {
   6   tenured_space* tenured;
   7   code_heap* code;
   8   std::vector<cell> *mark_stack;
   9
  10   full_collection_copier(tenured_space* tenured,
  11                          code_heap* code,
  12                          std::vector<cell> *mark_stack)
  13       : tenured(tenured), code(code), mark_stack(mark_stack) { }
  14
  15   object* fixup_data(object* obj) {
  16     if (tenured->contains_p(obj)) {
  17       if (!tenured->state.marked_p((cell)obj)) {
  18         tenured->state.set_marked_p((cell)obj, obj->size());
  19         mark_stack->push_back((cell)obj);
  20       }
  21       return obj;
  22     }
  23
  24     // Is there another forwarding pointer?
  25     while (obj->forwarding_pointer_p()) {
  26       object* dest = obj->forwarding_pointer();
  27       obj = dest;
  28     }
  29
  30     if (tenured->contains_p(obj)) {
  31       if (!tenured->state.marked_p((cell)obj)) {
  32         tenured->state.set_marked_p((cell)obj, obj->size());
  33         mark_stack->push_back((cell)obj);
  34       }
  35       return obj;
  36     }
  37
  38     cell size = obj->size();
  39     object* newpointer = tenured->allot(size);
  40     if (!newpointer)
  41       throw must_start_gc_again();
  42     memcpy(newpointer, obj, size);
  43     obj->forward_to(newpointer);
  44
  45     tenured->state.set_marked_p((cell)newpointer, newpointer->size());
  46     mark_stack->push_back((cell)newpointer);
  47     return newpointer;
  48   }
  49
  50   code_block* fixup_code(code_block* compiled) {
  51     if (!code->allocator->state.marked_p((cell)compiled)) {
  52       code->allocator->state.set_marked_p((cell)compiled, compiled->size());
  53       mark_stack->push_back((cell)compiled + 1);
  54     }
  55     return compiled;
  56   }
  57 };
  58
  59 void factor_vm::collect_mark_impl() {
  60   gc_event* event = current_gc->event;
  61   if (event)
  62     event->reset_timer();
  63
  64   slot_visitor<full_collection_copier>
  65       visitor(this, full_collection_copier(data->tenured, code, &mark_stack));
  66
  67   mark_stack.clear();
  68
  69   code->allocator->state.clear_mark_bits();
  70   data->tenured->state.clear_mark_bits();
  71
  72   visitor.visit_all_roots();
  73   visitor.visit_context_code_blocks();
  74   visitor.visit_uninitialized_code_blocks();
  75
  76   visitor.visit_mark_stack(&mark_stack);
  77
  78   data->reset_tenured();
  79   data->reset_aging();
  80   data->reset_nursery();
  81   code->clear_remembered_set();
  82
  83   if (event)
  84     event->ended_phase(PHASE_MARKING);
  85 }
  86
  87 void factor_vm::collect_sweep_impl() {
  88   gc_event* event = current_gc->event;
  89   if (event)
  90     event->reset_timer();
  91   data->tenured->sweep();
  92   if (event)
  93     event->ended_phase(PHASE_DATA_SWEEP);
  94
  95   // After a sweep, invalidate any code heap roots which are not
  96   // marked, so that if a block makes a tail call to a generic word,
  97   // and the PIC compiler triggers a GC, and the caller block gets GCd
  98   // as a result, the PIC code won't try to overwrite the call site
  99   mark_bits* state = &code->allocator->state;
 100   FACTOR_FOR_EACH(code_roots) {
 101     code_root* root = *iter;
 102     cell block = root->value & (~data_alignment - 1);
 103     if (root->valid && !state->marked_p(block))
 104       root->valid = false;
 105   }
 106
 107   if (event)
 108     event->reset_timer();
 109   code->sweep();
 110   if (event)
 111     event->ended_phase(PHASE_CODE_SWEEP);
 112 }
 113
 114 void factor_vm::collect_full() {
 115   collect_mark_impl();
 116   collect_sweep_impl();
 117
 118   if (data->low_memory_p()) {
 119     // Full GC did not free up enough memory. Grow the heap.
 120     set_current_gc_op(COLLECT_GROWING_DATA_HEAP_OP);
 121     collect_growing_data_heap(0);
 122   } else if (data->high_fragmentation_p()) {
 123     // Enough free memory, but it is not contiguous. Perform a
 124     // compaction.
 125     set_current_gc_op(COLLECT_COMPACT_OP);
 126     collect_compact_impl();
 127   }
 128
 129   code->flush_icache();
 130 }
 131
 132 }