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Master: Native compiler doesn't always compile lambda forms. |
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Sat, 15 Jul 2023 12:10:06 +0000 |
In the master branch:
(i) emacs -Q
(ii) C-x b foo.el <RET>
(iii) Insert into foo.el:
;; -*- lexical-binding:t -*-
(iv) M-x emacs-lisp-mode
(v) Insert into foo.el:
(defun foo () "foo doc string"
(lambda (bar) "lambda doc string" (car bar)))
(vi) With point after the function, C-x C-e to evaluate it.
(vii) M-: (native-compile 'foo)
This returns #<subr foo>
(viii) M-: (foo)
This returns the lambda form as a byte-compiled function. This is a bug:
it should return the lambda form as a native-compiled function.
Note: this bug is also in the emacs-29 branch.
--
Alan Mackenzie (Nuremberg, Germany).
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Re: bug#64646: Master: Native compiler doesn't always compile lambda forms. |
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Wed, 8 Nov 2023 20:59:42 +0000 |
Hello, Andrea.
On Thu, Nov 02, 2023 at 13:32:21 -0400, Andrea Corallo wrote:
> Alan Mackenzie <acm@muc.de> writes:
> > This bug doesn't seem to be moving, so ....
> > On Wed, Jul 26, 2023 at 10:57:01 -0400, Andrea Corallo wrote:
> >> Alan Mackenzie <acm@muc.de> writes:
> >> >> I'm not 100% convinced this behaviour is a bug tho.
> >> > I don't understand that. Why might it be incorrect to compile that inner
> >> > lambda natively?
> >> Hi Alan,
> >> I'm not saying it would be incorrect. I'm suggesting that if is not
> >> specified what's the expected behaviour of compiling by name the outer
> >> lambda it might not be a bug.
> >> When we compile a whole compilation unit we indeed have to compile all
> >> functions, in this case what we promised is I think not defined.
> > I still don't understand that. The doc string for native-compile says:
> > Compile FUNCTION-OR-FILE into native code.
> > .. I can't see any reason not also to compile inner lambda functions
> > natively.
> > Anyhow, to fix this bug (if such it be) is easy:
> > diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
> > index 181e5ca96a1..2360fbaa494 100644
> > --- a/lisp/emacs-lisp/comp.el
> > +++ b/lisp/emacs-lisp/comp.el
> > @@ -1359,7 +1359,12 @@ comp-add-func-to-ctxt
> > (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))))
> > + (comp-add-func-to-ctxt func))
> > + ;; Handle any lambda functions in BYTE-CODE.
> > + (maphash (lambda (key val)
> > + (unless (eq key (aref byte-code 1))
> > + (comp-intern-func-in-ctxt key val)))
> > + byte-to-native-lambdas-h)))
> > (cl-defmethod comp-spill-lap-function ((form list))
> > "Byte-compile FORM, spilling data from the byte compiler."
> > What do you say?
> LGTM as long as indeed it does not regress any test. Speaking of which
> with the patch I guess we want a test to cover this.
Thanks. I've committed a patch for this, including two extra tests which
test that a nested lambda function also gets native compiled.
I'm closing the bug with this post.
> > Incidentally, the code in the various comp-spill-lap-function methods
> > together with comp-intern-func-in-ctxt appears to have some code
> > duplication. Would it be possible to have the symbol and list methods of
> > comp-spill-lap-function simply call comp-intern-func-in-ctxt the way the
> > string method does? That would simplify those two methods quite a bit.
> Mmmh maybe, I think one has to try to see if the result is satisfactory.
I've done this refactoring too. The symbol and list methods for
comp-spill-lap-function now have 17 and 15 lines respectively. I hope
you like it!
> Thanks
> Andrea
--
Alan Mackenzie (Nuremberg, Germany).
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