bug#39997: High CPU load and no return value with 3.0.0

bug#39997: High CPU load and no return value with 3.0.0

[Roel Janssen]

Dear Guile hackers,

When I use the "md5" module from guile-lib (release 0.2.6.1) together
with the following snippet in Guile 3.0.0, it never returns, while on
Guile 2.2.6, it returns the MD5 sum of the input string:
---
(use-modules (md5))

(define (md5-from-string input)
  (call-with-input-string input md5))

(define (random-ascii length)
  "Returns a random string of ASCII characters of length LENGTH."
  (list->string
   (map (lambda _ (integer->char (+ (random 95) 32)))
        (iota length))))

(display
 (md5-from-string
  (random-ascii 32)))
---

Could you point me in the right direction for finding the problem?

This could be completely off-topic:
I also noticed that the function "read-string!/partial" (used by the
md5 module) no longer appears in the manual since the Guile 2.2.  Is
the usage of this function considered deprecated?

Kind regards,
Roel Janssen

bug#39997: High CPU load and no return value with 3.0.0

[Ludovic Courtès]

Hi,

Roel Janssen <roel@gnu.org> skribis:

> When I use the "md5" module from guile-lib (release 0.2.6.1) together
> with the following snippet in Guile 3.0.0, it never returns, while on
> Guile 2.2.6, it returns the MD5 sum of the input string:
> ---
> (use-modules (md5))
>
> (define (md5-from-string input)
>   (call-with-input-string input md5))
>
> (define (random-ascii length)
>   "Returns a random string of ASCII characters of length LENGTH."
>   (list->string
>    (map (lambda _ (integer->char (+ (random 95) 32)))
>         (iota length))))
>
> (display
>  (md5-from-string
>   (random-ascii 32)))
> ---
>
> Could you point me in the right direction for finding the problem?

The Guix package has this patch:

        '(begin
           ;; Work around miscompilation on Guile 3.0.0 at -O2:
           ;; <https://bugs.gnu.org/39251>.
           (substitute* "src/md5.scm"
             (("\\(define f-ash ash\\)")
              "(define f-ash (@ (guile) ash))\n")
             (("\\(define f-add \\+\\)")
              "(define f-add (@ (guile) +))\n"))
           #t)

It’s very likely that you’re hitting this problem.

HTH!

Ludo’.

bug#39997: High CPU load and no return value with 3.0.0

[Roel Janssen]

On Wed, 2020-03-11 at 12:07 +0100, Ludovic Courtès wrote:
> Hi,
> 
> Roel Janssen <roel@gnu.org> skribis:
> 
> > When I use the "md5" module from guile-lib (release 0.2.6.1)
> > together
> > with the following snippet in Guile 3.0.0, it never returns, while
> > on
> > Guile 2.2.6, it returns the MD5 sum of the input string:
> > ---
> > (use-modules (md5))
> > 
> > (define (md5-from-string input)
> >   (call-with-input-string input md5))
> > 
> > (define (random-ascii length)
> >   "Returns a random string of ASCII characters of length LENGTH."
> >   (list->string
> >    (map (lambda _ (integer->char (+ (random 95) 32)))
> >         (iota length))))
> > 
> > (display
> >  (md5-from-string
> >   (random-ascii 32)))
> > ---
> > 
> > Could you point me in the right direction for finding the problem?
> 
> The Guix package has this patch:
> 
>         '(begin
>            ;; Work around miscompilation on Guile 3.0.0 at -O2:
>            ;; <https://bugs.gnu.org/39251>;.
>            (substitute* "src/md5.scm"
>              (("\\(define f-ash ash\\)")
>               "(define f-ash (@ (guile) ash))\n")
>              (("\\(define f-add \\+\\)")
>               "(define f-add (@ (guile) +))\n"))
>            #t)
> 
> It’s very likely that you’re hitting this problem.

Yes!  Thanks for sharing this fix.
I applied the same changes to my code and now I don't encounter the bug
anymore.

I tested the patched code with both guile-2.2 and guile-3.0.  Do you
know whether this will also work with guile-2.0?  (I'd like to keep
things compatible with guile-2.0 for a few more years).

Kind regards,
Roel Janssen

bug#39997: High CPU load and no return value with 3.0.0

[Ludovic Courtès]

Roel Janssen <roel@gnu.org> skribis:

> On Wed, 2020-03-11 at 12:07 +0100, Ludovic Courtès wrote:

[...]

>> The Guix package has this patch:
>> 
>>         '(begin
>>            ;; Work around miscompilation on Guile 3.0.0 at -O2:
>>            ;; <https://bugs.gnu.org/39251>;.
>>            (substitute* "src/md5.scm"
>>              (("\\(define f-ash ash\\)")
>>               "(define f-ash (@ (guile) ash))\n")
>>              (("\\(define f-add \\+\\)")
>>               "(define f-add (@ (guile) +))\n"))
>>            #t)
>> 
>> It’s very likely that you’re hitting this problem.
>
> Yes!  Thanks for sharing this fix.
> I applied the same changes to my code and now I don't encounter the bug
> anymore.
>
> I tested the patched code with both guile-2.2 and guile-3.0.  Do you
> know whether this will also work with guile-2.0?  (I'd like to keep
> things compatible with guile-2.0 for a few more years).

Yes, the change above also works for Guile 2.0.

Ludo’.

bug#39997: High CPU load and no return value with 3.0.0

[Roel Janssen]

On Wed, 2020-03-11 at 15:05 +0100, Ludovic Courtès wrote:
> Roel Janssen <roel@gnu.org> skribis:
> 
> > On Wed, 2020-03-11 at 12:07 +0100, Ludovic Courtès wrote:
> 
> [...]
> 
> > > The Guix package has this patch:
> > > 
> > >         '(begin
> > >            ;; Work around miscompilation on Guile 3.0.0 at -O2:
> > >            ;; <https://bugs.gnu.org/39251>;;.
> > >            (substitute* "src/md5.scm"
> > >              (("\\(define f-ash ash\\)")
> > >               "(define f-ash (@ (guile) ash))\n")
> > >              (("\\(define f-add \\+\\)")
> > >               "(define f-add (@ (guile) +))\n"))
> > >            #t)
> > > 
> > > It’s very likely that you’re hitting this problem.
> > 
> > Yes!  Thanks for sharing this fix.
> > I applied the same changes to my code and now I don't encounter the
> > bug
> > anymore.
> > 
> > I tested the patched code with both guile-2.2 and guile-3.0.  Do
> > you
> > know whether this will also work with guile-2.0?  (I'd like to keep
> > things compatible with guile-2.0 for a few more years).
> 
> Yes, the change above also works for Guile 2.0.

Thanks for the confirmation.  I'm closing this bug, as it is basically
a duplicate of #39251.

Kind regards,
Roel Janssen