1.0.32.29: Add build flag :sb-xref-for-internals.

[sbcl.git] / src / compiler / stack.lisp

diff --git a/src/compiler/stack.lisp b/src/compiler/stack.lisp
index 4ac4c7a..51d416d 100644 (file)
--- a/src/compiler/stack.lisp
+++ b/src/compiler/stack.lisp
@@ -61,6 +61,7 @@
 ;;; been changed.
 (defun merge-uvl-live-sets (early late)
   (declare (type list early late))
+  ;; FIXME: O(N^2)
   (dolist (e late early)
     (pushnew e early)))
 
@@ -93,21 +94,28 @@
                      block
                      (lambda (dx-cleanup)
                        (dolist (lvar (cleanup-info dx-cleanup))
-                         (let* ((generator (lvar-use lvar))
-                                (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, should be kept alive until the
-                           ;; object is deallocated.
-                           (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)))))))
+                         (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))))))))
 
     (setf (ir2-block-end-stack 2block) new-end)