From: Guillermo J. Rozas <edu/mit/csail/zurich/gjr>
Date: Fri, 4 May 1990 15:15:18 +0000 (+0000)
Subject: Fix a bug in walk-procedure that manifested itself in sf/subst.
X-Git-Tag: 20090517-FFI~11410
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=14db35c8de97ba9c2b591a7e8e805a14258a8258;p=mit-scheme.git

Fix a bug in walk-procedure that manifested itself in sf/subst.
The free variables in closures are determined exclusively by the
closure block, not by the free variables of the procedure block.
---

diff --git a/v7/src/compiler/fgopt/subfre.scm b/v7/src/compiler/fgopt/subfre.scm
index 48d858548..41d37b9fd 100644
--- a/v7/src/compiler/fgopt/subfre.scm
+++ b/v7/src/compiler/fgopt/subfre.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/fgopt/subfre.scm,v 1.5 1990/05/03 15:09:24 jinx Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/fgopt/subfre.scm,v 1.6 1990/05/04 15:15:18 jinx Exp $
 
 Copyright (c) 1988, 1989, 1990 Massachusetts Institute of Technology
 
@@ -74,32 +74,31 @@ MIT in each case. |#
 
 (define (walk-procedure proc)
   (define (default)
-    ;; This should be OK for open procedures, but perhaps
-    ;; we should look at the closure block for closures.
     (list-transform-negative
 	(block-free-variables (procedure-block proc))
       lvalue-integrated?))
 
+  (define (closure)
+    (block-bound-variables
+     (block-shared-block (procedure-closing-block proc))))
+
   (if (or (not (procedure/closure? proc))
 	  (procedure/trivial-closure? proc))
       (default)
       (let ((how (procedure-closure-cons proc)))
 	(case (car how)
 	  ((NORMAL)
-	   (default))
+	   (closure))
 	  ((DESCENDANT)
-	   ;; This will automatically imply saving the ancestor
+	   ;; This should automatically imply saving the ancestor
 	   ;; for stack overwrites since that is how the free
 	   ;; variables will be obtained.
-	   ;; Is this really true?
-	   ;; What if some of them are in registers?
-	   ;; What if it is a descendant of an indirected procedure?
-	   (default))
+	   (closure))
 	  ((INDIRECTED)
 	   ;; In reality, only the indirection variable or the default
 	   ;; set is needed, depending on where the reference occurs.
 	   ;; This is always safe, however.
-	   (cons (cdr how) (default)))
+	   (cons (cdr how) (closure)))
 	  (else
 	   (error "walk-procedure: Unknown closure method" proc))))))