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 void full_collector::trace_context_code_blocks() {
  17   code_visitor.visit_context_code_blocks();
  18 }
  19
  20 void full_collector::trace_code_roots() { code_visitor.visit_code_roots(); }
  21
  22 void full_collector::trace_object_code_block(object* obj) {
  23   code_visitor.visit_object_code_block(obj);
  24 }
  25
  26 /* After a sweep, invalidate any code heap roots which are not marked,
  27    so that if a block makes a tail call to a generic word, and the PIC
  28    compiler triggers a GC, and the caller block gets gets GCd as a result,
  29    the PIC code won't try to overwrite the call site */
  30 void factor_vm::update_code_roots_for_sweep() {
  31   std::vector<code_root*>::const_iterator iter = code_roots.begin();
  32   std::vector<code_root*>::const_iterator end = code_roots.end();
  33
  34   mark_bits<code_block>* state = &code->allocator->state;
  35
  36   for (; iter < end; iter++) {
  37     code_root* root = *iter;
  38     code_block* block = (code_block*)(root->value & (~data_alignment - 1));
  39     if (root->valid && !state->marked_p(block))
  40       root->valid = false;
  41   }
  42 }
  43
  44 void factor_vm::collect_mark_impl(bool trace_contexts_p) {
  45   full_collector collector(this);
  46
  47   mark_stack.clear();
  48
  49   code->clear_mark_bits();
  50   data->tenured->clear_mark_bits();
  51
  52   collector.trace_roots();
  53   if (trace_contexts_p) {
  54     collector.trace_contexts();
  55     collector.trace_context_code_blocks();
  56     collector.trace_code_roots();
  57   }
  58
  59   while (!mark_stack.empty()) {
  60     cell ptr = mark_stack.back();
  61     mark_stack.pop_back();
  62
  63     if (ptr & 1) {
  64       code_block* compiled = (code_block*)(ptr - 1);
  65       collector.trace_code_block(compiled);
  66     } else {
  67       object* obj = (object*)ptr;
  68       collector.trace_object(obj);
  69       collector.trace_object_code_block(obj);
  70     }
  71   }
  72
  73   data->reset_generation(data->tenured);
  74   data->reset_generation(data->aging);
  75   data->reset_generation(&nursery);
  76   code->clear_remembered_set();
  77 }
  78
  79 void factor_vm::collect_sweep_impl() {
  80   gc_event* event = current_gc->event;
  81
  82   if (event)
  83     event->started_data_sweep();
  84   data->tenured->sweep();
  85   if (event)
  86     event->ended_data_sweep();
  87
  88   update_code_roots_for_sweep();
  89
  90   if (event)
  91     event->started_code_sweep();
  92   code->sweep();
  93   if (event)
  94     event->ended_code_sweep();
  95 }
  96
  97 void factor_vm::collect_full(bool trace_contexts_p) {
  98   collect_mark_impl(trace_contexts_p);
  99   collect_sweep_impl();
 100
 101   if (data->low_memory_p()) {
 102     /* Full GC did not free up enough memory. Grow the heap. */
 103     set_current_gc_op(collect_growing_heap_op);
 104     collect_growing_heap(0, trace_contexts_p);
 105   } else if (data->high_fragmentation_p()) {
 106     /* Enough free memory, but it is not contiguous. Perform a
 107        compaction. */
 108     set_current_gc_op(collect_compact_op);
 109     collect_compact_impl(trace_contexts_p);
 110   }
 111
 112   code->flush_icache();
 113 }
 114
 115 }