1.0.19.7: refactor stack allocation decisions

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

diff --git a/src/compiler/locall.lisp b/src/compiler/locall.lisp
index 0a463c3..fe1dea8 100644 (file)
--- a/src/compiler/locall.lisp
+++ b/src/compiler/locall.lisp
@@ -43,17 +43,11 @@
              (setf (car args) nil)))
   (values))
 
-(defun handle-nested-dynamic-extent-lvars (lvar)
+(defun handle-nested-dynamic-extent-lvars (dx lvar)
   (let ((uses (lvar-uses lvar)))
-    ;; Stack analysis wants DX value generators to end their
-    ;; blocks. Uses of mupltiple used LVARs already end their blocks,
-    ;; so we just need to process used-once LVARs.
-    ;;
-    ;; FIXME: Is this true? I cannot trigger any bad behaviour if I nuke this
-    ;; form, and the only assumption regarding block ends I see in in stack
-    ;; analysis is the one made by MAP-BLOCK-NLXES, which assumes that nodes
-    ;; with cleanups in their lexenv end their blocks. If this one is
-    ;; necessary, we should explain why in more detail. --NS 2008-07-19
+    ;; DX value generators must end their blocks: see UPDATE-UVL-LIVE-SETS.
+    ;; Uses of mupltiple-use LVARs already end their blocks, so we just need
+    ;; to process uses of single-use LVARs.
     (when (node-p uses)
       (node-ends-block uses))
     ;; If this LVAR's USE is good for DX, it is either a CAST, or it
@@ -61,46 +55,37 @@
     (flet ((recurse (use)
              (etypecase use
                (cast
-                (handle-nested-dynamic-extent-lvars (cast-value use)))
+                (handle-nested-dynamic-extent-lvars dx (cast-value use)))
                (combination
                 (loop for arg in (combination-args use)
-                      when (lvar-good-for-dx-p arg)
-                      append (handle-nested-dynamic-extent-lvars arg))))))
+                      when (lvar-good-for-dx-p arg dx)
+                      append (handle-nested-dynamic-extent-lvars dx arg))))))
       (cons lvar
             (if (listp uses)
                 (loop for use in uses
-                      when (use-good-for-dx-p use)
+                      when (use-good-for-dx-p use dx)
                       nconc (recurse use))
-                (when (use-good-for-dx-p uses)
+                (when (use-good-for-dx-p uses dx)
                   (recurse uses)))))))
 
 (defun recognize-dynamic-extent-lvars (call fun)
   (declare (type combination call) (type clambda fun))
   (loop for arg in (basic-combination-args call)
-        and var in (lambda-vars fun)
-        when (and arg (lambda-var-dynamic-extent var)
-                  (not (lvar-dynamic-extent arg)))
-        append (handle-nested-dynamic-extent-lvars arg) into dx-lvars
+        for var in (lambda-vars fun)
+        for dx = (lambda-var-dynamic-extent var)
+        when (and dx arg (not (lvar-dynamic-extent arg)))
+        append (handle-nested-dynamic-extent-lvars dx arg) into dx-lvars
         finally (when dx-lvars
                   ;; Stack analysis requires that the CALL ends the block, so
                   ;; that MAP-BLOCK-NLXES sees the cleanup we insert here.
                   (node-ends-block call)
-                  (binding* ((before-ctran (node-prev call))
-                             (nil (ensure-block-start before-ctran))
-                             (block (ctran-block before-ctran))
-                             (new-call-ctran (make-ctran :kind :inside-block
-                                                         :next call
-                                                         :block block))
-                             (entry (with-ir1-environment-from-node call
-                                      (make-entry :prev before-ctran
-                                                  :next new-call-ctran)))
-                             (cleanup (make-cleanup :kind :dynamic-extent
-                                                    :mess-up entry
-                                                    :info dx-lvars)))
-                    (setf (node-prev call) new-call-ctran)
-                    (setf (ctran-next before-ctran) entry)
-                    (setf (ctran-use new-call-ctran) entry)
+                  (let* ((entry (with-ir1-environment-from-node call
+                                  (make-entry)))
+                         (cleanup (make-cleanup :kind :dynamic-extent
+                                                :mess-up entry
+                                                :info dx-lvars)))
                     (setf (entry-cleanup entry) cleanup)
+                    (insert-node-before call entry)
                     (setf (node-lexenv call)
                           (make-lexenv :default (node-lexenv call)
                                        :cleanup cleanup))