static size_t
gc_sweep_page(pic_state *pic, struct heap_page *page)
{
union header *bp, *p, *head = NULL, *tail = NULL;
struct object *obj;
size_t alive = 0, nunits;
for (bp = page->u.basep; ; bp = bp->s.ptr) {
p = bp + (bp->s.size ? bp->s.size : 1); /* first bp's size is 0, so force advnce */
while (p != bp->s.ptr) {
if (p < page->u.basep || page->u.basep + PAGE_UNITS <= p) {
goto escape;
}
obj = (struct object *) p;
nunits = unitsof(obj_type(pic, obj));
if (obj->u.basic.tt & GC_MARK) {
obj->u.basic.tt &= ~GC_MARK;
alive += nunits;
} else {
gc_finalize_object(pic, obj);
if (head == NULL) {
head = p;
}
if (tail != NULL) {
tail->s.ptr = p;
}
tail = p;
tail->s.size = nunits;
tail->s.ptr = NULL; /* We can safely reuse ptr field of dead object */
}
p += nunits;
}
}
escape:
/* free! */
while (head != NULL) {
p = head;
head = head->s.ptr;
free_chunk(pic, p);
}
return alive;
}
void
pic_gc(pic_state *pic)
{
struct context *cxt;
size_t j;
khash_t(oblist) *s = &pic->oblist;
struct symbol *sym;
int it;
struct object *obj, *prev, *next;
assert(pic->gc_attrs == NULL);
if (! pic->gc_enable) {
return;
}
/* scan objects */
for (cxt = pic->cxt; cxt != NULL; cxt = cxt->prev) {
if (cxt->fp) gc_mark_object(pic, (struct object *)cxt->fp);
if (cxt->sp) gc_mark_object(pic, (struct object *)cxt->sp);
if (cxt->irep) gc_mark_object(pic, (struct object *)cxt->irep);
gc_mark(pic, cxt->conts);
}
for (j = 0; j < pic->ai; ++j) {
gc_mark_object(pic, (struct object *)pic->arena[j]);
}
gc_mark(pic, pic->globals);
gc_mark(pic, pic->halt);
/* scan weak references */
do {
struct object *key;
pic_value val;
int it;
khash_t(attr) *h;
struct attr *attr;
j = 0;
attr = pic->gc_attrs;
while (attr != NULL) {
h = &attr->hash;
for (it = kh_begin(h); it != kh_end(h); ++it) {
if (! kh_exist(h, it))
continue;
key = kh_key(h, it);
val = kh_val(h, it);
if (is_alive(key)) {
if (pic_obj_p(pic, val) && ! is_alive((struct object *) pic_ptr(pic, val))) {
gc_mark(pic, val);
++j;
}
}
}
attr = attr->prev;
}
} while (j > 0);
/* reclaim dead weak references */
while (pic->gc_attrs != NULL) {
khash_t(attr) *h = &pic->gc_attrs->hash;
for (it = kh_begin(h); it != kh_end(h); ++it) {
if (! kh_exist(h, it))
continue;
obj = kh_key(h, it);
if (! is_alive(obj)) {
kh_del(attr, h, it);
}
}
pic->gc_attrs = pic->gc_attrs->prev;
}
for (it = kh_begin(s); it != kh_end(s); ++it) {
if (! kh_exist(s, it))
continue;
sym = kh_val(s, it);
if (sym && ! is_alive((struct object *)sym)) {
kh_del(oblist, s, it);
}
}
/* reclaim dead objects */
for (prev = &pic->gc_head, obj = prev->next; obj != &pic->gc_head; prev = obj, obj = next) {
next = obj->next;
if (is_alive(obj)) {
unmark(obj);
} else {
gc_finalize_object(pic, obj);
pic_free(pic, obj);
prev->next = next;
obj = prev;
}
}
}