vm/full_collector.cpp

   1 #include "master.hpp"
   2
   3 namespace factor {
   4
   5 full_collector::full_collector(factor_vm* parent)
   6     : collector<tenured_space, full_policy>(parent, parent->data->tenured,
   7                                             full_policy(parent)),
   8       code_visitor(parent, workhorse) {}
   9
  10 void full_collector::trace_code_block(code_block* compiled) {
  11   data_visitor.visit_code_block_objects(compiled);
  12   data_visitor.visit_embedded_literals(compiled);
  13   code_visitor.visit_embedded_code_pointers(compiled);
  14 }
  15
  16 /* After a sweep, invalidate any code heap roots which are not marked,
  17    so that if a block makes a tail call to a generic word, and the PIC
  18    compiler triggers a GC, and the caller block gets gets GCd as a result,
  19    the PIC code won't try to overwrite the call site */
  20 void factor_vm::update_code_roots_for_sweep() {
  21   std::vector<code_root*>::const_iterator iter = code_roots.begin();
  22   std::vector<code_root*>::const_iterator end = code_roots.end();
  23
  24   mark_bits<code_block>* state = &code->allocator->state;
  25
  26   for (; iter < end; iter++) {
  27     code_root* root = *iter;
  28     code_block* block = (code_block*)(root->value & (~data_alignment - 1));
  29     if (root->valid && !state->marked_p(block))
  30       root->valid = false;
  31   }
  32 }
  33
  34 void factor_vm::collect_mark_impl(bool trace_contexts_p) {
  35   full_collector collector(this);
  36
  37   mark_stack.clear();
  38
  39   code->clear_mark_bits();
  40   data->tenured->clear_mark_bits();
  41
  42   collector.data_visitor.visit_roots();
  43   if (trace_contexts_p) {
  44     collector.data_visitor.visit_contexts();
  45     collector.code_visitor.visit_context_code_blocks();
  46     collector.code_visitor.visit_code_roots();
  47   }
  48
  49   while (!mark_stack.empty()) {
  50     cell ptr = mark_stack.back();
  51     mark_stack.pop_back();
  52
  53     if (ptr & 1) {
  54       code_block* compiled = (code_block*)(ptr - 1);
  55       collector.trace_code_block(compiled);
  56     } else {
  57       object* obj = (object*)ptr;
  58       collector.trace_object(obj);
  59       collector.code_visitor.visit_object_code_block(obj);
  60     }
  61   }
  62
  63   data->reset_generation(data->tenured);
  64   data->reset_generation(data->aging);
  65   data->reset_generation(&nursery);
  66   code->clear_remembered_set();
  67 }
  68
  69 void factor_vm::collect_sweep_impl() {
  70   gc_event* event = current_gc->event;
  71
  72   if (event)
  73     event->started_data_sweep();
  74   data->tenured->sweep();
  75   if (event)
  76     event->ended_data_sweep();
  77
  78   update_code_roots_for_sweep();
  79
  80   if (event)
  81     event->started_code_sweep();
  82   code->sweep();
  83   if (event)
  84     event->ended_code_sweep();
  85 }
  86
  87 void factor_vm::collect_full(bool trace_contexts_p) {
  88   collect_mark_impl(trace_contexts_p);
  89   collect_sweep_impl();
  90
  91   if (data->low_memory_p()) {
  92     /* Full GC did not free up enough memory. Grow the heap. */
  93     set_current_gc_op(collect_growing_heap_op);
  94     collect_growing_heap(0, trace_contexts_p);
  95   } else if (data->high_fragmentation_p()) {
  96     /* Enough free memory, but it is not contiguous. Perform a
  97        compaction. */
  98     set_current_gc_op(collect_compact_op);
  99     collect_compact_impl(trace_contexts_p);
 100   }
 101
 102   code->flush_icache();
 103 }
 104
 105 }