vm/full_collector.cpp

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