Steel Bank Common Lisp

Update of /cvsroot/sbcl/sbcl/src/compiler
In directory sc8-pr-cvs8.sourceforge.net:/tmp/cvs-serv11974/src/compiler

Modified Files:
	locall.lisp 
Log Message:
1.0.18.23: ALL calls with DX arguments should end their blocks

 * Consider this a clarification of 1.0.18.22: MAP-BLOCK-NLXES will
   miss calls that don't end their blocks.

   If let-conversion happens, as is the case most of the time, this is
   not an issue, since the LAMBDA-CALL-LEXENV will hold the lexenv
   with the cleanup.

   A :LET functional, however, should never appear in
   RECOGNIZE-DYNAMIC-EXTENT-LVARS, since let-conversion doesn't happen
   until later -- so the conditional was bogus.

   So: delete the conditional, and write a comment that points in
   the place where we depend on the block-endingness.

 * Add a FIXME note to another DX related place where we make nodes
   end their blocks, which I don't quite understand.


Index: locall.lisp
===================================================================
RCS file: /cvsroot/sbcl/sbcl/src/compiler/locall.lisp,v
retrieving revision 1.86
retrieving revision 1.87
diff -u -d -r1.86 -r1.87
--- locall.lisp	18 Jul 2008 20:07:59 -0000	1.86
+++ locall.lisp	19 Jul 2008 09:48:15 -0000	1.87
@@ -48,6 +48,12 @@
     ;; 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
     (when (node-p uses)
       (node-ends-block uses))
     ;; If this LVAR's USE is good for DX, it is either a CAST, or it
@@ -76,11 +82,9 @@
                   (not (lvar-dynamic-extent arg)))
         append (handle-nested-dynamic-extent-lvars arg) into dx-lvars
         finally (when dx-lvars
-                  ;; A call to non-LET with DX args must end its block,
-                  ;; otherwise stack analysis will not see the combination and
-                  ;; the associated cleanup/entry.
-                  (unless (eq :let (functional-kind fun))
-                    (node-ends-block call))
+                  ;; 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))