factor/vm/objects.cpp

#include "master.hpp"

namespace factor
{

void factor_vm::primitive_special_object()
{
	fixnum e = untag_fixnum(dpeek());
	drepl(special_objects[e]);
}

void factor_vm::primitive_set_special_object()
{
	fixnum e = untag_fixnum(dpop());
	cell value = dpop();
	special_objects[e] = value;
}

void factor_vm::primitive_identity_hashcode()
{
	cell tagged = dpeek();
	if(immediate_p(tagged))
		drepl(tagged & ~TAG_MASK);
	else
	{
		object *obj = untag<object>(tagged);
		if(obj->hashcode() == 0)
		{
			/* Use megamorphic_cache_misses as a random source of randomness */
			obj->set_hashcode(((cell)obj / block_granularity) ^ dispatch_stats.megamorphic_cache_hits);
		}
		drepl(tag_fixnum(obj->hashcode()));
	}
}

void factor_vm::primitive_set_slot()
{
	fixnum slot = untag_fixnum(dpop());
	object *obj = untag<object>(dpop());
	cell value = dpop();

	cell *slot_ptr = &obj->slots()[slot];
	*slot_ptr = value;
	write_barrier(slot_ptr);
}

cell factor_vm::clone_object(cell obj_)
{
	data_root<object> obj(obj_,this);

	if(immediate_p(obj.value()))
		return obj.value();
	else
	{
		cell size = object_size(obj.value());
		object *new_obj = allot_object(obj.type(),size);
		memcpy(new_obj,obj.untagged(),size);
		new_obj->set_hashcode(0);
		return tag_dynamic(new_obj);
	}
}

void factor_vm::primitive_clone()
{
	drepl(clone_object(dpeek()));
}

/* Size of the object pointed to by a tagged pointer */
cell factor_vm::object_size(cell tagged)
{
	if(immediate_p(tagged))
		return 0;
	else
		return untag<object>(tagged)->size();
}

void factor_vm::primitive_size()
{
	box_unsigned_cell(object_size(dpop()));
}

struct slot_become_visitor {
	std::map<object *,object *> *become_map;

	explicit slot_become_visitor(std::map<object *,object *> *become_map_) :
		become_map(become_map_) {}

	object *operator()(object *old)
	{
		std::map<object *,object *>::const_iterator iter = become_map->find(old);
		if(iter != become_map->end())
			return iter->second;
		else
			return old;
	}
};

struct object_become_visitor {
	slot_visitor<slot_become_visitor> *workhorse;

	explicit object_become_visitor(slot_visitor<slot_become_visitor> *workhorse_) :
		workhorse(workhorse_) {}

	void operator()(object *obj)
	{
		workhorse->visit_slots(obj);
	}
};

/* classes.tuple uses this to reshape tuples; tools.deploy.shaker uses this
   to coalesce equal but distinct quotations and wrappers. */
void factor_vm::primitive_become()
{
	array *new_objects = untag_check<array>(dpop());
	array *old_objects = untag_check<array>(dpop());

	cell capacity = array_capacity(new_objects);
	if(capacity != array_capacity(old_objects))
		critical_error("bad parameters to become",0);

	/* Build the forwarding map */
	std::map<object *,object *> become_map;

	for(cell i = 0; i < capacity; i++)
	{
		tagged<object> old_obj(array_nth(old_objects,i));
		tagged<object> new_obj(array_nth(new_objects,i));

		if(old_obj != new_obj)
			become_map[old_obj.untagged()] = new_obj.untagged();
	}

	/* Update all references to old objects to point to new objects */
	slot_visitor<slot_become_visitor> workhorse(this,slot_become_visitor(&become_map));
	workhorse.visit_roots();
	workhorse.visit_contexts();

	object_become_visitor object_visitor(&workhorse);
	each_object(object_visitor);

	/* Since we may have introduced old->new references, need to revisit
	all objects on a minor GC. */
	data->mark_all_cards();
	primitive_minor_gc();

	/* If a word's definition quotation was in old_objects and the
	   quotation in new_objects is not compiled, we might leak memory
	   by referencing the old quotation unless we recompile all
	   unoptimized words. */
	compile_all_words();

	/* Update references to old objects in the code heap */
	update_code_heap_words_and_literals();
}

}