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   slot_visitor<full_collection_copier>
  61       visitor(this, full_collection_copier(data->tenured, code, &mark_stack));
  62
  63   mark_stack.clear();
  64
  65   code->allocator->state.clear_mark_bits();
  66   data->tenured->state.clear_mark_bits();
  67
  68   visitor.visit_all_roots();
  69   visitor.visit_context_code_blocks();
  70   visitor.visit_uninitialized_code_blocks();
  71
  72   visitor.visit_mark_stack(&mark_stack);
  73
  74   data->reset_tenured();
  75   data->reset_aging();
  76   data->reset_nursery();
  77   code->clear_remembered_set();
  78 }
  79
  80 void factor_vm::collect_sweep_impl() {
  81   gc_event* event = current_gc->event;
  82
  83   if (event)
  84     event->reset_timer();
  85   data->tenured->sweep();
  86   if (event)
  87     event->ended_phase(PHASE_DATA_SWEEP);
  88
  89   // After a sweep, invalidate any code heap roots which are not
  90   // marked, so that if a block makes a tail call to a generic word,
  91   // and the PIC compiler triggers a GC, and the caller block gets GCd
  92   // as a result, the PIC code won't try to overwrite the call site
  93   mark_bits* state = &code->allocator->state;
  94   FACTOR_FOR_EACH(code_roots) {
  95     code_root* root = *iter;
  96     cell block = root->value & (~data_alignment - 1);
  97     if (root->valid && !state->marked_p(block))
  98       root->valid = false;
  99   }
 100
 101   if (event)
 102     event->reset_timer();
 103   code->sweep();
 104   if (event)
 105     event->ended_phase(PHASE_CODE_SWEEP);
 106 }
 107
 108 void factor_vm::collect_full() {
 109   collect_mark_impl();
 110   collect_sweep_impl();
 111
 112   if (data->low_memory_p()) {
 113     // Full GC did not free up enough memory. Grow the heap.
 114     set_current_gc_op(COLLECT_GROWING_DATA_HEAP_OP);
 115     collect_growing_data_heap(0);
 116   } else if (data->high_fragmentation_p()) {
 117     // Enough free memory, but it is not contiguous. Perform a
 118     // compaction.
 119     set_current_gc_op(COLLECT_COMPACT_OP);
 120     collect_compact_impl();
 121   }
 122
 123   code->flush_icache();
 124 }
 125
 126 }