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Revert "Fix closure-conversion of shadowed captured lambda-lifted vars"

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This reverts commit 3ec8c8b3ae.

It was committed to a stable branch without prior discussion;
see bug#53071.
This commit is contained in:
Mattias Engdegård 2022-01-12 19:47:39 +01:00
parent a1ac6bd47e
commit 22ddd2ba13
3 changed files with 6 additions and 220 deletions
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31
lisp/emacs-lisp/cconv.el
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@ -304,25 +304,6 @@ of converted forms."
`(,@(nreverse special-forms) ,@(macroexp-unprogn body))))
funcbody)))
(defun cconv--lifted-arg (var env)
"The argument to use for VAR in λ-lifted calls according to ENV.
This is used when VAR is being shadowed; we may still need its value for
such calls."
(let ((mapping (cdr (assq var env))))
(pcase-exhaustive mapping
(`(internal-get-closed-var . ,_)
;; The variable is captured.
mapping)
(`(car-safe (internal-get-closed-var . ,_))
;; The variable is mutably captured; skip
;; the indirection step because the variable is
;; passed "by reference" to the λ-lifted function.
(cadr mapping))
((or '() `(car-safe ,(pred symbolp)))
;; The variable is not captured; use the (shadowed) variable value.
;; (If the mapping is `(car-safe SYMBOL)', SYMBOL is always VAR.
var))))
(defun cconv-convert (form env extend)
;; This function actually rewrites the tree.
"Return FORM with all its lambdas changed so they are closed.
@ -447,11 +428,10 @@ places where they originally did not directly appear."
;; One of the lambda-lifted vars is shadowed, so add
;; a reference to the outside binding and arrange to use
;; that reference.
(let ((var-def (cconv--lifted-arg var env))
(closedsym (make-symbol (format "closed-%s" var))))
(let ((closedsym (make-symbol (format "closed-%s" var))))
(setq new-env (cconv--remap-llv new-env var closedsym))
(setq new-extend (cons closedsym (remq var new-extend)))
(push `(,closedsym ,var-def) binders-new)))
(push `(,closedsym ,var) binders-new)))
;; We push the element after redefined free variables are
;; processed. This is important to avoid the bug when free
@ -469,13 +449,14 @@ places where they originally did not directly appear."
;; before we know that the var will be in `new-extend' (bug#24171).
(dolist (binder binders-new)
(when (memq (car-safe binder) new-extend)
;; One of the lambda-lifted vars is shadowed.
;; One of the lambda-lifted vars is shadowed, so add
;; a reference to the outside binding and arrange to use
;; that reference.
(let* ((var (car-safe binder))
(var-def (cconv--lifted-arg var env))
(closedsym (make-symbol (format "closed-%s" var))))
(setq new-env (cconv--remap-llv new-env var closedsym))
(setq new-extend (cons closedsym (remq var new-extend)))
(push `(,closedsym ,var-def) binders-new)))))
(push `(,closedsym ,var) binders-new)))))
`(,letsym ,(nreverse binders-new)
. ,(mapcar (lambda (form)