GC.latest_compact_info

static VALUE
gc_compact_stats(VALUE self)
{
    rb_objspace_t *objspace = rb_gc_get_objspace();
    VALUE h = rb_hash_new();
    VALUE considered = rb_hash_new();
    VALUE moved = rb_hash_new();
    VALUE moved_up = rb_hash_new();
    VALUE moved_down = rb_hash_new();

    for (size_t i = 0; i < T_MASK; i++) {
        if (objspace->rcompactor.considered_count_table[i]) {
            rb_hash_aset(considered, type_sym(i), SIZET2NUM(objspace->rcompactor.considered_count_table[i]));
        }

        if (objspace->rcompactor.moved_count_table[i]) {
            rb_hash_aset(moved, type_sym(i), SIZET2NUM(objspace->rcompactor.moved_count_table[i]));
        }

        if (objspace->rcompactor.moved_up_count_table[i]) {
            rb_hash_aset(moved_up, type_sym(i), SIZET2NUM(objspace->rcompactor.moved_up_count_table[i]));
        }

        if (objspace->rcompactor.moved_down_count_table[i]) {
            rb_hash_aset(moved_down, type_sym(i), SIZET2NUM(objspace->rcompactor.moved_down_count_table[i]));
        }
    }

    rb_hash_aset(h, ID2SYM(rb_intern("considered")), considered);
    rb_hash_aset(h, ID2SYM(rb_intern("moved")), moved);
    rb_hash_aset(h, ID2SYM(rb_intern("moved_up")), moved_up);
    rb_hash_aset(h, ID2SYM(rb_intern("moved_down")), moved_down);

    return h;
}