[Caml-list] Delimcc bug

[Caml-list] Delimcc bug

[Evgeny Khramtsov]

Does anyone know where to report bugs in Delimcc?
Is it even supported?
Under some conditions I have segfaults in it when compiled natively in
4.04.1.

Re: [Caml-list] Delimcc bug

[oleg]

On Fri, Jun 02, 2017 at 05:32:21PM +0300, Evgeny Khramtsov wrote:
> Does anyone know where to report bugs in Delimcc?
> Is it even supported?
> Under some conditions I have segfaults in it when compiled natively in
> 4.04.1.
> 

You can send me directly, or send to the list if you want. But be sure
you fetch the latest version from my web page. The problem is usually
GCC, which optimizes too much. So, special flags are required to switch
off some optmizations. You can see in the Makefile. If you have a very
recent version of GCC, chances are it needs some more flags to disable
too aggressive optimizations.

Re: [Caml-list] Delimcc bug

[Ivan Gotovchits]

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Wouldn't it be better to add directly to the implementation a GCC pragma
[1] or an attribute [2] that will explicitly disable the optimizations?


[1]:
https://gcc.gnu.org/onlinedocs/gcc/Function-Specific-Option-Pragmas.html#Function-Specific-Option-Pragmas
[2]:
https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes



On Fri, Jun 2, 2017 at 5:05 PM, <oleg@okmij.org> wrote:

> On Fri, Jun 02, 2017 at 05:32:21PM +0300, Evgeny Khramtsov wrote:
> > Does anyone know where to report bugs in Delimcc?
> > Is it even supported?
> > Under some conditions I have segfaults in it when compiled natively in
> > 4.04.1.
> >
>
> You can send me directly, or send to the list if you want. But be sure
> you fetch the latest version from my web page. The problem is usually
> GCC, which optimizes too much. So, special flags are required to switch
> off some optmizations. You can see in the Makefile. If you have a very
> recent version of GCC, chances are it needs some more flags to disable
> too aggressive optimizations.
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>

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Re: [Caml-list] Delimcc bug

[Evgeny Khramtsov]

Fri, 2 Jun 2017 11:05:57 -0400
oleg@okmij.org wrote:

> You can send me directly, or send to the list if you want. But be sure
> you fetch the latest version from my web page. The problem is usually
> GCC, which optimizes too much. So, special flags are required to
> switch off some optmizations. You can see in the Makefile. If you
> have a very recent version of GCC, chances are it needs some more
> flags to disable too aggressive optimizations.

I'm using delimcc from opam, the url it's pointing to is
http://okmij.org/ftp/continuations/caml-shift.tar.gz
Sometimes it segfaults, sometimes it stops with "take_subcont: can't
happen". I tried with gcc 6.2.0 and 4.9.2. Do I need even older gcc? :)

Re: [Caml-list] Delimcc bug

[Evgeny Khramtsov]

Fri, 2 Jun 2017 11:05:57 -0400
oleg@okmij.org wrote:

> So, special flags are required to switch
> off some optmizations.

I confirm, replacing -O2 with -O0 flag for compiling stacks-native.c
fixes the problem.
However, I think this (or something better) should be applied in the
patch used to compile delimcc by opam (makefile_fix.patch).

Re: [Caml-list] Delimcc bug

[Jeremy Yallop]

On 3 June 2017 at 06:26, Evgeny Khramtsov <xramtsov@gmail.com> wrote:
> Fri, 2 Jun 2017 11:05:57 -0400
> oleg@okmij.org wrote:
>
>> So, special flags are required to switch
>> off some optmizations.
>
> I confirm, replacing -O2 with -O0 flag for compiling stacks-native.c
> fixes the problem.
> However, I think this (or something better) should be applied in the
> patch used to compile delimcc by opam (makefile_fix.patch).

The best way to achieve this is to send a pull request to the
opam-repository repository:

   https://github.com/ocaml/opam-repository/pulls

mentioning the package maintainer (@rgrinberg) in the description.

Kind regards,

Jeremy

Re: [Caml-list] Delimcc bug

[Evgeny Khramtsov]

Sat, 3 Jun 2017 10:08:12 +0100
Jeremy Yallop <yallop@gmail.com> wrote:

> The best way to achieve this is to send a pull request to the
> opam-repository repository:
> 
>    https://github.com/ocaml/opam-repository/pulls

Done: https://github.com/ocaml/opam-repository/pull/9401
Thanks for the tip :)