+ block
+ (lambda (dx-cleanup)
+ (dolist (lvar (cleanup-info dx-cleanup))
+ (do-uses (generator lvar)
+ (let* ((block (node-block generator))
+ (2block (block-info block)))
+ ;; DX objects, living in the LVAR, are alive in
+ ;; the environment, protected by the CLEANUP. We
+ ;; also cannot move them (because, in general, we
+ ;; cannot track all references to them).
+ ;; Therefore, everything, allocated deeper than a
+ ;; DX object -- that is, before the DX object --
+ ;; should be kept alive until the object is
+ ;; deallocated.
+ ;;
+ ;; Since DX generators end their blocks, we can
+ ;; find out UVLs allocated before them by looking
+ ;; at the stack at the end of the block.
+ ;;
+ ;; FIXME: This is not quite true: REFs to DX
+ ;; closures don't end their blocks!
+ (setq new-end (merge-uvl-live-sets
+ new-end (ir2-block-end-stack 2block)))
+ (setq new-end (merge-uvl-live-sets
+ new-end (ir2-block-pushed 2block))))))))