diff options
Diffstat (limited to 'lisp/emacs-lisp/cconv.el')
| -rw-r--r-- | lisp/emacs-lisp/cconv.el | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/lisp/emacs-lisp/cconv.el b/lisp/emacs-lisp/cconv.el index 3abbf716875..7cec91bfa82 100644 --- a/lisp/emacs-lisp/cconv.el +++ b/lisp/emacs-lisp/cconv.el @@ -32,7 +32,7 @@ ;; Here is a brief explanation how this code works. ;; Firstly, we analyze the tree by calling cconv-analyze-form. ;; This function finds all mutated variables, all functions that are suitable -;; for lambda lifting and all variables captured by closure. It passes the tree +;; for lambda lifting and all variables captured by closure. It passes the tree ;; once, returning a list of three lists. ;; ;; Then we calculate the intersection of the first and third lists returned by @@ -304,6 +304,25 @@ 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 ,exp) + ;; The variable is mutably captured; skip + ;; the indirection step because the variable is + ;; passed "by reference" to the λ-lifted function. + exp) + (_ + ;; 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. @@ -428,10 +447,11 @@ 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 ((closedsym (make-symbol (format "closed-%s" var)))) + (let ((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) binders-new))) + (push `(,closedsym ,var-def) binders-new))) ;; We push the element after redefined free variables are ;; processed. This is important to avoid the bug when free @@ -449,14 +469,13 @@ 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, so add - ;; a reference to the outside binding and arrange to use - ;; that reference. + ;; One of the lambda-lifted vars is shadowed. (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) binders-new))))) + (push `(,closedsym ,var-def) binders-new))))) `(,letsym ,(nreverse binders-new) . ,(mapcar (lambda (form) @@ -608,10 +627,9 @@ FORM is the parent form that binds this var." (`((,(and var (guard (eq ?_ (aref (symbol-name var) 0)))) . ,_) ,_ ,_ ,_ ,_) ;; FIXME: Convert this warning to use `macroexp--warn-wrap' - ;; so as to give better position information and obey - ;; `byte-compile-warnings'. - (byte-compile-warn - "%s `%S' not left unused" varkind var)) + ;; so as to give better position information. + (when (byte-compile-warning-enabled-p 'not-unused var) + (byte-compile-warn "%s `%S' not left unused" varkind var))) ((and (let (or 'let* 'let) (car form)) `((,var) ;; (or `(,var nil) : Too many false positives: bug#47080 t nil ,_ ,_)) @@ -794,6 +812,8 @@ This function does not return anything but instead fills the ;; (`(declare . ,_) nil) ;The args don't contain code. (`(,_ . ,body-forms) ; First element is a function or whatever. + (unless (listp body-forms) + (signal 'wrong-type-argument (list 'proper-list-p form))) (dolist (form body-forms) (cconv-analyze-form form env))) ((pred symbolp) |