From: Pip Cet <pipcet@gmail.com>
To: 46834@debbugs.gnu.org
Subject: bug#46834: 28.0.50; byte-compiling the standard counter closure fails
Date: Sun, 28 Feb 2021 20:34:36 +0000 [thread overview]
Message-ID: <CAOqdjBcBtU=HH22EZiz_NBRyMSpKzRvbJ7SJNRwN=TMzek-F7A@mail.gmail.com> (raw)
In-Reply-To: <CAOqdjBeBwgTtTrrecExPb-toa54t6Vm6USO4F0fwWWYN62UYVw@mail.gmail.com>
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On Sun, Feb 28, 2021 at 7:57 PM Pip Cet <pipcet@gmail.com> wrote:
> Patch attached. I've looked through the generated bytecode for all of
> lisp/ and there appear to be no significant differences.
And I suppose we have to test it, too.
Pip
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From 7cdb59b37b278d5f3e95b2b5b1b8758defe70acf Mon Sep 17 00:00:00 2001
From: Pip Cet <pipcet@gmail.com>
Date: Sun, 28 Feb 2021 19:43:09 +0000
Subject: [PATCH] Compile closures that modify their bound vars correctly
(Bug#46834)
* lisp/emacs-lisp/bytecomp.el (byte-compile--reify-function):
Don't move let bindings into the lambda. Don't reverse list of
bindings.
* test/lisp/emacs-lisp/bytecomp-tests.el (bytecomp-reify-function):
Add tests.
---
lisp/emacs-lisp/bytecomp.el | 8 ++------
test/lisp/emacs-lisp/bytecomp-tests.el | 23 +++++++++++++++++++++++
2 files changed, 25 insertions(+), 6 deletions(-)
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index a2fe37a1ee586..7d00b453caf1c 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -2785,16 +2785,12 @@ byte-compile--reify-function
(dolist (binding env)
(cond
((consp binding)
- ;; We check shadowing by the args, so that the `let' can be moved
- ;; within the lambda, which can then be unfolded. FIXME: Some of those
- ;; bindings might be unused in `body'.
- (unless (memq (car binding) args) ;Shadowed.
- (push `(,(car binding) ',(cdr binding)) renv)))
+ (push `(,(car binding) ',(cdr binding)) renv))
((eq binding t))
(t (push `(defvar ,binding) body))))
(if (null renv)
`(lambda ,args ,@preamble ,@body)
- `(lambda ,args ,@preamble (let ,(nreverse renv) ,@body)))))
+ `(let ,renv (lambda ,args ,@preamble ,@body)))))
\f
;;;###autoload
(defun byte-compile (form)
diff --git a/test/lisp/emacs-lisp/bytecomp-tests.el b/test/lisp/emacs-lisp/bytecomp-tests.el
index fb84596ad3f40..03c267ccd0fef 100644
--- a/test/lisp/emacs-lisp/bytecomp-tests.el
+++ b/test/lisp/emacs-lisp/bytecomp-tests.el
@@ -1199,6 +1199,29 @@ bytecomp-local-defvar
(should (equal (funcall (eval fun t)) '(c d)))
(should (equal (funcall (byte-compile fun)) '(c d))))))
+(ert-deftest bytecomp-reify-function ()
+ "Check that closures that modify their bound variables are
+compiled correctly."
+ (cl-letf ((lexical-binding t)
+ ((symbol-function 'counter) nil))
+ (let ((x 0))
+ (defun counter () (cl-incf x))
+ (should (equal (counter) 1))
+ (should (equal (counter) 2))
+ ;; byte compiling should not cause counter to always return the
+ ;; same value (bug#46834)
+ (byte-compile 'counter)
+ (should (equal (counter) 3))
+ (should (equal (counter) 4)))
+ (let ((x 0))
+ (let ((x 1))
+ (defun counter () x)
+ (should (equal (counter) 1))
+ ;; byte compiling should not cause the outer binding to shadow
+ ;; the inner one (bug#46834)
+ (byte-compile 'counter)
+ (should (equal (counter) 1))))))
+
;; Local Variables:
;; no-byte-compile: t
;; End:
--
2.30.1
next prev parent reply other threads:[~2021-02-28 20:34 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-28 15:04 bug#46834: 28.0.50; byte-compiling the standard counter closure fails Pip Cet
2021-02-28 19:57 ` Pip Cet
2021-02-28 20:34 ` Pip Cet [this message]
2021-03-01 14:23 ` Stefan Monnier
2021-03-01 15:01 ` Pip Cet
2021-03-01 16:02 ` Stefan Monnier
2021-03-02 7:00 ` Lars Ingebrigtsen
2021-03-02 7:31 ` Pip Cet
2021-03-02 7:34 ` Lars Ingebrigtsen
2021-03-02 7:36 ` Pip Cet
2021-03-02 13:16 ` Eli Zaretskii
2021-03-02 13:19 ` Pip Cet
2021-03-02 13:48 ` Eli Zaretskii
2021-03-01 13:16 ` Lars Ingebrigtsen
2021-03-01 14:34 ` Stefan Monnier
2021-03-01 15:16 ` Pip Cet
2021-03-01 16:15 ` Stefan Monnier
2021-03-01 16:41 ` Pip Cet
2021-03-01 17:01 ` Stefan Monnier
2021-03-01 17:13 ` Pip Cet
2021-03-01 16:31 ` Eli Zaretskii
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