bool BakerGC::handle_promotions() {
if(promoted_stack_.empty() && fully_scanned_p()) return false;
while(!promoted_stack_.empty() || !fully_scanned_p()) {
while(!promoted_stack_.empty()) {
Object* obj = promoted_stack_.back();
promoted_stack_.pop_back();
scan_object(obj);
}
copy_unscanned();
}
return true;
}
/* Perform garbage collection on the young objects. */
void BakerGC::collect(GCData& data) {
#ifdef RBX_GC_STATS
stats::GCStats::get()->bytes_copied.start();
stats::GCStats::get()->objects_copied.start();
stats::GCStats::get()->objects_promoted.start();
stats::GCStats::get()->collect_young.start();
#endif
Object* tmp;
ObjectArray *current_rs = object_memory->remember_set;
object_memory->remember_set = new ObjectArray(0);
total_objects = 0;
// Tracks all objects that we promoted during this run, so
// we can scan them at the end.
promoted_ = new ObjectArray(0);
promoted_current = promoted_insert = promoted_->begin();
for(ObjectArray::iterator oi = current_rs->begin();
oi != current_rs->end();
++oi) {
tmp = *oi;
// unremember_object throws a NULL in to remove an object
// so we don't have to compact the set in unremember
if(tmp) {
assert(tmp->zone == MatureObjectZone);
assert(!tmp->forwarded_p());
// Remove the Remember bit, since we're clearing the set.
tmp->clear_remember();
scan_object(tmp);
}
}
delete current_rs;
for(Roots::Iterator i(data.roots()); i.more(); i.advance()) {
tmp = i->get();
if(tmp->reference_p() && tmp->young_object_p()) {
i->set(saw_object(tmp));
}
}
for(VariableRootBuffers::Iterator i(data.variable_buffers());
i.more(); i.advance()) {
Object*** buffer = i->buffer();
for(int idx = 0; idx < i->size(); idx++) {
Object** var = buffer[idx];
Object* tmp = *var;
if(tmp->reference_p() && tmp->young_object_p()) {
*var = saw_object(tmp);
}
}
}
// Walk all the call frames
for(CallFrameLocationList::iterator i = data.call_frames().begin();
i != data.call_frames().end();
i++) {
CallFrame** loc = *i;
walk_call_frame(*loc);
}
/* Ok, now handle all promoted objects. This is setup a little weird
* so I should explain.
*
* We want to scan each promoted object. But this scanning will likely
* cause more objects to be promoted. Adding to an ObjectArray that your
* iterating over blows up the iterators, so instead we rotate the
* current promoted set out as we iterator over it, and stick an
* empty ObjectArray in.
*
* This way, when there are no more objects that are promoted, the last
* ObjectArray will be empty.
* */
promoted_current = promoted_insert = promoted_->begin();
while(promoted_->size() > 0 || !fully_scanned_p()) {
if(promoted_->size() > 0) {
for(;promoted_current != promoted_->end();
++promoted_current) {
tmp = *promoted_current;
assert(tmp->zone == MatureObjectZone);
scan_object(tmp);
if(watched_p(tmp)) {
std::cout << "detected " << tmp << " during scan of promoted objects.\n";
}
}
promoted_->resize(promoted_insert - promoted_->begin());
promoted_current = promoted_insert = promoted_->begin();
}
/* As we're handling promoted objects, also handle unscanned objects.
* Scanning these unscanned objects (via the scan pointer) will
* cause more promotions. */
copy_unscanned();
}
assert(promoted_->size() == 0);
delete promoted_;
promoted_ = NULL;
assert(fully_scanned_p());
/* Another than is going to be found is found now, so we go back and
* look at everything in current and call delete_object() on anything
* thats not been forwarded. */
find_lost_souls();
/* Check any weakrefs and replace dead objects with nil*/
clean_weakrefs(true);
/* Swap the 2 halves */
Heap *x = next;
next = current;
current = x;
next->reset();
#ifdef RBX_GC_STATS
stats::GCStats::get()->collect_young.stop();
stats::GCStats::get()->objects_copied.stop();
stats::GCStats::get()->objects_promoted.stop();
stats::GCStats::get()->bytes_copied.stop();
#endif
}
