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 // After a sweep, invalidate any code heap roots which are not marked,
  60 // so that if a block makes a tail call to a generic word, and the PIC
  61 // compiler triggers a GC, and the caller block gets GCd as a result,
  62 // the PIC code won't try to overwrite the call site
  63 void factor_vm::update_code_roots_for_sweep() {
  64   mark_bits* state = &code->allocator->state;
  65
  66   FACTOR_FOR_EACH(code_roots) {
  67     code_root* root = *iter;
  68     cell block = root->value & (~data_alignment - 1);
  69     if (root->valid && !state->marked_p(block))
  70       root->valid = false;
  71   }
  72 }
  73
  74 void factor_vm::collect_mark_impl() {
  75   slot_visitor<full_collection_copier>
  76       visitor(this, full_collection_copier(data->tenured, code, &mark_stack));
  77
  78   mark_stack.clear();
  79
  80   code->allocator->state.clear_mark_bits();
  81   data->tenured->state.clear_mark_bits();
  82
  83   visitor.visit_all_roots();
  84   visitor.visit_context_code_blocks();
  85   visitor.visit_uninitialized_code_blocks();
  86
  87   visitor.visit_mark_stack(&mark_stack);
  88
  89   data->reset_tenured();
  90   data->reset_aging();
  91   data->reset_nursery();
  92   code->clear_remembered_set();
  93 }
  94
  95 void factor_vm::collect_sweep_impl() {
  96   gc_event* event = current_gc->event;
  97
  98   if (event)
  99     event->reset_timer();
 100   data->tenured->sweep();
 101   if (event)
 102     event->ended_data_sweep();
 103
 104   update_code_roots_for_sweep();
 105
 106   if (event)
 107     event->reset_timer();
 108   code->sweep();
 109   if (event)
 110     event->ended_code_sweep();
 111 }
 112
 113 void factor_vm::collect_full() {
 114   collect_mark_impl();
 115   collect_sweep_impl();
 116
 117   if (data->low_memory_p()) {
 118     // Full GC did not free up enough memory. Grow the heap.
 119     set_current_gc_op(collect_growing_heap_op);
 120     collect_growing_heap(0);
 121   } else if (data->high_fragmentation_p()) {
 122     // Enough free memory, but it is not contiguous. Perform a
 123     // compaction.
 124     set_current_gc_op(collect_compact_op);
 125     collect_compact_impl();
 126   }
 127
 128   code->flush_icache();
 129 }
 130
 131 }