From 13827d4d2a432bf65e1f93a4ee1e058a8e24ed3e Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Tue, 13 Dec 1988 13:03:50 +0000
Subject: [PATCH] * Change `block' to `context' where needed.

* New abstractions support owning and disowning of block children.
---
 v7/src/compiler/fgopt/envopt.scm | 56 ++++++++++++--------------------
 1 file changed, 20 insertions(+), 36 deletions(-)

diff --git a/v7/src/compiler/fgopt/envopt.scm b/v7/src/compiler/fgopt/envopt.scm
index 5868e3e85..25a6be5f2 100644
--- a/v7/src/compiler/fgopt/envopt.scm
+++ b/v7/src/compiler/fgopt/envopt.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/fgopt/envopt.scm,v 1.3 1988/12/06 18:56:41 jinx Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/fgopt/envopt.scm,v 1.4 1988/12/13 13:03:50 cph Exp $
 
 Copyright (c) 1988 Massachusetts Institute of Technology
 
@@ -165,43 +165,27 @@ MIT in each case. |#
 	     (enqueue-nodes! (procedure-free-callers procedure)))
 	    (else 'DONE)))))
 
-(define (application-is-call-to? application block)
-  (and (application/combination? application)
-       (let ((op (rvalue-known-value (application-operator application))))
-	 (and op
-	      (rvalue/procedure? op)
-	      (eq? (application-block application) block)))))
-
 (define (choose-target-block! procedure)
   (let ((callers (procedure-free-callers procedure))
-	(closing-block (procedure-closing-block procedure)))
-    ;; The following conditional makes some cases of LET-like procedures
-    ;; track their parents in order to avoid closing over the same
-    ;; variables twice.
-    (if (or (not (null? callers))
-	    (not (procedure-always-known-operator? procedure))
-	    (not (for-all?
-		  (procedure-applications procedure)
-		  (lambda (app)
-		    (application-is-call-to? app closing-block)))))
-	(let ((target-block (procedure-target-block procedure)))
-	  (if (and (not (eq? closing-block target-block))
-		   (block-ancestor? closing-block target-block))
-	      (let ((myself (procedure-block procedure)))
-		(set-procedure-target-block! procedure closing-block)
-		(set-procedure-closing-block! procedure target-block)
-		(set-block-children!
-		 closing-block
-		 (delq! myself (block-children closing-block)))
-		(set-block-disowned-children!
-		 closing-block
-		 (cons myself (block-disowned-children closing-block)))
-		(set-block-children!
-		 target-block
-		 (cons myself (block-children target-block))))
-	      (set-procedure-target-block! procedure closing-block)))
-	(set-procedure-target-block! procedure closing-block))
-    'DONE))
+	(parent (procedure-closing-block procedure))
+	(target-block (procedure-target-block procedure)))
+    ;; This now becomes `original-block-parent' of the procedure's
+    ;; invocation block.
+    (set-procedure-target-block! procedure parent)
+    (if (and
+	 ;; The following clause makes some cases of LET-like
+	 ;; procedures track their parents in order to avoid closing
+	 ;; over the same variables twice.
+	 (not (and (null? callers)
+		   (procedure-always-known-operator? procedure)
+		   (for-all? (procedure-applications procedure)
+		     (lambda (application)
+		       (eq? (application-block application) parent)))))
+	 (block-ancestor? parent target-block))
+	(let ((myself (procedure-block procedure)))
+	  (disown-block-child! parent myself)
+	  (own-block-child! target-block myself)))
+    unspecific))
 
 ;;; Utilities
 
-- 
2.25.1