Subject: Re: bug#64642: 29.0.92; Native compiler doesn't compile dynamically bound functions.

From: Alan Mackenzie <[email-masked]>
Date: Sat, 15 Jul 2023 15:17:20 +0000

Hello, Eli and Andrea.

On Sat, Jul 15, 2023 at 12:53:51 +0300, Eli Zaretskii wrote:
> > Date: Sat, 15 Jul 2023 09:38:13 +0000
> > From: Alan Mackenzie <[email-masked]>

> > Hello, Emacs.

> > In the Emacs 29 pretest version (or the master version):
> > (i) emacs -Q
> > (ii) C-x b foo.el <RET>
> > (iii) M-x emacs-lisp-mode <RET>
> > Don't set lexical-binding in this buffer.
> > (iv) Enter a function called foo:
> >     (defun foo () "foo doc string"
> >       (lambda (bar) "lambda doc string" (car bar)))
> > (v) With point after the function, evaluate it with C-x C-e.

> > (vi) M-: (native-compile 'foo)
> > This signals an error, native-compiler-error-dyn-func.  This is a bug.

> > #########################################################################

> > The immediate cause of the bug is in the version of
> > comp-spill-lap-function which processes named functions (comp.el).
> > Unlike the other version of the cl-defmethod (which processes lambda
> > functions), there is no code for dynamic functions here.

> > If the intention is not to process dynamic functions, this should be
> > indicated by an error message rather than a signal.  Personally, I feel
> > that dynamic functions ought to be handled in Emacs-29.

> > Fixing this bug should be relatively straightforward, since it should
> > only involve copying and adapting the corresponding code in the lambda
> > version of comp-spill-lap-function.

> Adding Andrea.

> It is unlikely that this will be fixed in Emacs 29, unless the fix is
> so simple that will surprise me.

Here is a fix.  Its simplicity probably doesn't surprise you (Eli), but
the change is entirely within one function, and a lot of the patch is
just whitespace changes.

There are no problems running make bootstrap or make check with patch in
place.  It also solves the bug; unless there are good reasons dynamically
bound functions weren't handled.  Andrea?

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index 322df0e86a1..3e0725cef4f 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -1274,33 +1274,45 @@ comp-spill-lap-function
           (make-temp-file (comp-c-func-name function-name "freefn-")
                           nil ".eln")))
   (let* ((f (symbol-function function-name))
+         (byte-code (byte-compile function-name))
          (c-name (comp-c-func-name function-name "F"))
-         (func (make-comp-func-l :name function-name
-                                 :c-name c-name
-                                 :doc (documentation f t)
-                                 :int-spec (interactive-form f)
-                                 :command-modes (command-modes f)
-                                 :speed (comp-spill-speed function-name)
-                                 :pure (comp-spill-decl-spec function-name
-                                                             'pure))))
+         (func
+          (if (comp-lex-byte-func-p byte-code)
+              (make-comp-func-l :name function-name
+                                :c-name c-name
+                                :doc (documentation f t)
+                                :int-spec (interactive-form f)
+                                :command-modes (command-modes f)
+                                :speed (comp-spill-speed function-name)
+                                :pure (comp-spill-decl-spec function-name
+                                                            'pure))
+            (make-comp-func-d :name function-name
+                              :c-name c-name
+                              :doc (documentation f t)
+                              :int-spec (interactive-form f)
+                              :command-modes (command-modes f)
+                              :speed (comp-spill-speed function-name)
+                              :pure (comp-spill-decl-spec function-name
+                                                          'pure)))))
       (when (byte-code-function-p f)
         (signal 'native-compiler-error
                 "can't native compile an already byte-compiled function"))
-      (setf (comp-func-byte-func func)
-            (byte-compile (comp-func-name func)))
+      (setf (comp-func-byte-func func) byte-code)
       (let ((lap (byte-to-native-lambda-lap
                   (gethash (aref (comp-func-byte-func func) 1)
                            byte-to-native-lambdas-h))))
         (cl-assert lap)
         (comp-log lap 2 t)
-        (let ((arg-list (aref (comp-func-byte-func func) 0)))
-          (setf (comp-func-l-args func)
-                (comp-decrypt-arg-list arg-list function-name)
-                (comp-func-lap func)
-                lap
-                (comp-func-frame-size func)
-                (comp-byte-frame-size (comp-func-byte-func func))))
-        (setf (comp-ctxt-top-level-forms comp-ctxt)
+        (if (comp-func-l-p func)
+            (let ((arg-list (aref (comp-func-byte-func func) 0)))
+              (setf (comp-func-l-args func)
+                    (comp-decrypt-arg-list arg-list function-name)))
+          (setf (comp-func-d-lambda-list func) (cadr f)))
+        (setf (comp-func-lap func)
+              lap
+              (comp-func-frame-size func)
+              (comp-byte-frame-size (comp-func-byte-func func))
+              (comp-ctxt-top-level-forms comp-ctxt)
               (list (make-byte-to-native-func-def :name function-name
                                                   :c-name c-name)))
         (comp-add-func-to-ctxt func))))

-- 
Alan Mackenzie (Nuremberg, Germany).