X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fphysenvanal.lisp;h=2ded90095178c306d2df2c2f4e4aa6c6f7ee695b;hb=148e3820ad314a9b59d0133c1d60eaac4af9118b;hp=e319ef811810d99a3d6735fd08798df88f4c9b24;hpb=1c2d2fa984c9d0bf07b5a1e5eeae2eade5cc4cb4;p=sbcl.git

diff --git a/src/compiler/physenvanal.lisp b/src/compiler/physenvanal.lisp
index e319ef8..2ded900 100644
--- a/src/compiler/physenvanal.lisp
+++ b/src/compiler/physenvanal.lisp
@@ -30,10 +30,10 @@
   (declare (type component component))
   (aver (every (lambda (x)
 		 (eq (functional-kind x) :deleted))
-	       (component-new-funs component)))
-  (setf (component-new-funs component) ())
-  (dolist (fun (component-lambdas component))
-    (reinit-lambda-physenv fun))
+	       (component-new-functionals component)))
+  (setf (component-new-functionals component) ())
+  (dolist (clambda (component-lambdas component))
+    (reinit-lambda-physenv clambda))
   (mapc #'add-lambda-vars-and-let-vars-to-closures
 	(component-lambdas component))
 
@@ -171,11 +171,22 @@
 	    (setq did-something t)
 	    (close-over var ref-physenv physenv))))
       (dolist (set (basic-var-sets var))
-	(let ((set-physenv (get-node-physenv set)))
-	  (unless (eq set-physenv physenv)
-	    (setq did-something t)
-	    (setf (lambda-var-indirect var) t)
-	    (close-over var set-physenv physenv)))))
+
+	;; Variables which are set but never referenced can be
+	;; optimized away, and closing over them here would just
+	;; interfere with that. (In bug 147, it *did* interfere with
+	;; that, causing confusion later. This UNLESS solves that
+	;; problem, but I (WHN) am not 100% sure it's best to solve
+	;; the problem this way instead of somehow solving it
+	;; somewhere upstream and just doing (AVER (LEAF-REFS VAR))
+	;; here.)
+	(unless (null (leaf-refs var))
+
+	  (let ((set-physenv (get-node-physenv set)))
+	    (unless (eq set-physenv physenv)
+	      (setf did-something t
+		    (lambda-var-indirect var) t)
+	      (close-over var set-physenv physenv))))))
     did-something))
 
 ;;; Find any variables in CLAMBDA -- either directly in LAMBDA-VARS or
@@ -229,7 +240,7 @@
 ;;;
 ;;; If a CATCH or an UNWIND-protect, then we set the LEXENV for the
 ;;; last node in the cleanup code to be the enclosing environment, to
-;;; represent the fact that the binding was undone as a side-effect of
+;;; represent the fact that the binding was undone as a side effect of
 ;;; the exit. This will cause a lexical exit to be broken up if we are
 ;;; actually exiting the scope (i.e. a BLOCK), and will also do any
 ;;; other cleanups that may have to be done on the way.
@@ -263,12 +274,12 @@
 ;;; EXIT into ENV. This is called for each non-local exit node, of
 ;;; which there may be several per exit continuation. This is what we
 ;;; do:
-;;; -- If there isn't any NLX-Info entry in the environment, make
+;;; -- If there isn't any NLX-INFO entry in the environment, make
 ;;;    an entry stub, otherwise just move the exit block link to
 ;;;    the component tail.
-;;; -- Close over the NLX-Info in the exit environment.
-;;; -- If the exit is from an :Escape function, then substitute a
-;;;    constant reference to NLX-Info structure for the escape
+;;; -- Close over the NLX-INFO in the exit environment.
+;;; -- If the exit is from an :ESCAPE function, then substitute a
+;;;    constant reference to NLX-INFO structure for the escape
 ;;;    function reference. This will cause the escape function to
 ;;;    be deleted (although not removed from the DFO.)  The escape
 ;;;    function is no longer needed, and we don't want to emit code
@@ -280,26 +291,23 @@
   (let ((entry (exit-entry exit))
 	(cont (node-cont exit))
 	(exit-fun (node-home-lambda exit)))
-
     (if (find-nlx-info entry cont)
 	(let ((block (node-block exit)))
 	  (aver (= (length (block-succ block)) 1))
 	  (unlink-blocks block (first (block-succ block)))
 	  (link-blocks block (component-tail (block-component block))))
 	(insert-nlx-entry-stub exit env))
-
     (let ((info (find-nlx-info entry cont)))
       (aver info)
       (close-over info (node-physenv exit) env)
       (when (eq (functional-kind exit-fun) :escape)
-	(mapc #'(lambda (x)
-		  (setf (node-derived-type x) *wild-type*))
+	(mapc (lambda (x)
+		(setf (node-derived-type x) *wild-type*))
 	      (leaf-refs exit-fun))
 	(substitute-leaf (find-constant info) exit-fun)
 	(let ((node (block-last (nlx-info-target info))))
 	  (delete-continuation-use node)
 	  (add-continuation-use node (nlx-info-continuation info))))))
-
   (values))
 
 ;;; Iterate over the EXITs in COMPONENT, calling NOTE-NON-LOCAL-EXIT
@@ -312,11 +320,10 @@
   (dolist (lambda (component-lambdas component))
     (dolist (entry (lambda-entries lambda))
       (dolist (exit (entry-exits entry))
-	(let ((target-env (node-physenv entry)))
-	  (if (eq (node-physenv exit) target-env)
+	(let ((target-physenv (node-physenv entry)))
+	  (if (eq (node-physenv exit) target-physenv)
 	      (maybe-delete-exit exit)
-	      (note-non-local-exit target-env exit))))))
-
+	      (note-non-local-exit target-physenv exit))))))
   (values))
 
 ;;;; cleanup emission
@@ -326,7 +333,10 @@
 ;;; in an implicit MV-PROG1. We have to force local call analysis of
 ;;; new references to UNWIND-PROTECT cleanup functions. If we don't
 ;;; actually have to do anything, then we don't insert any cleanup
-;;; code.
+;;; code. (FIXME: There's some confusion here, left over from CMU CL
+;;; comments. CLEANUP1 isn't mentioned in the code of this function.
+;;; It is in code elsewhere, but if the comments for this function
+;;; mention it they should explain the relationship to the other code.)
 ;;;
 ;;; If we do insert cleanup code, we check that BLOCK1 doesn't end in
 ;;; a "tail" local call.
@@ -392,20 +402,29 @@
 	      (emit-cleanups block1 block2)))))))
   (values))
 
-;;; Mark all tail-recursive uses of function result continuations with
-;;; the corresponding TAIL-SET. Nodes whose type is NIL (i.e. don't
-;;; return) such as calls to ERROR are never annotated as tail in
-;;; order to preserve debugging information.
+;;; Mark optimizable tail-recursive uses of function result
+;;; continuations with the corresponding TAIL-SET.
 (defun tail-annotate (component)
   (declare (type component component))
   (dolist (fun (component-lambdas component))
     (let ((ret (lambda-return fun)))
+      ;; Nodes whose type is NIL (i.e. don't return) such as calls to
+      ;; ERROR are never annotated as TAIL-P, in order to preserve
+      ;; debugging information.
+      ;;
+      ;; FIXME: It might be better to add another DEFKNOWN property
+      ;; (e.g. NO-TAIL-RECURSION) and use it for error-handling
+      ;; functions like ERROR, instead of spreading this special case
+      ;; net so widely.
       (when ret
 	(let ((result (return-result ret)))
 	  (do-uses (use result)
-	    (when (and (immediately-used-p result use)
-		     (or (not (eq (node-derived-type use) *empty-type*))
-			 (not (basic-combination-p use))
-			 (eq (basic-combination-kind use) :local)))
-		(setf (node-tail-p use) t)))))))
+	    (when (and (policy use
+			       (or (> space debug)
+				   (> speed debug)))
+		       (immediately-used-p result use)
+		       (or (not (eq (node-derived-type use) *empty-type*))
+			   (not (basic-combination-p use))
+			   (eq (basic-combination-kind use) :local)))
+	      (setf (node-tail-p use) t)))))))
   (values))