Why is GCL built with gcc@4.9?

Why is GCL built with gcc@4.9?

[Mark H Weaver]

Hi Efraim,

I'm curious about this commit of yours from April 2017:

--8<---------------cut here---------------start------------->8---
commit 5c7815f205e9164d4b82378de91bee7a65bcfbcb
Author: Efraim Flashner <efraim@flashner.co.il>
Date:   Mon Apr 10 05:20:09 2017 +0300

    gnu: gcl: Build with gcc@4.9.
    
    * gnu/packages/lisp.scm (gcl)[native-inputs]: Add gcc@4.9.
--8<---------------cut here---------------end--------------->8---

Do you remember why you did this?  There's no explanation in the
comments, nor in the commit log, nor in the 'bug-guix' or 'guix-devel'
email archives from around that time.

I'd like to remove it, and I've verified that on x86_64-linux, GCL
builds successfully with the default compiler.

In general, it would be good to include comments with rationale for
workarounds like this, so that we have some idea of when the workaround
can be removed, and what tests we must do to ensure that the original
problem has been addressed.

     Thanks,
       Mark

Re: Why is GCL built with gcc@4.9?

[Efraim Flashner]

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On Thu, Dec 13, 2018 at 12:03:59AM -0500, Mark H Weaver wrote:
> Hi Efraim,
> 
> I'm curious about this commit of yours from April 2017:
> 
> --8<---------------cut here---------------start------------->8---
> commit 5c7815f205e9164d4b82378de91bee7a65bcfbcb
> Author: Efraim Flashner <efraim@flashner.co.il>
> Date:   Mon Apr 10 05:20:09 2017 +0300
> 
>     gnu: gcl: Build with gcc@4.9.
>     
>     * gnu/packages/lisp.scm (gcl)[native-inputs]: Add gcc@4.9.
> --8<---------------cut here---------------end--------------->8---
> 
> Do you remember why you did this?  There's no explanation in the
> comments, nor in the commit log, nor in the 'bug-guix' or 'guix-devel'
> email archives from around that time.
> 
> I'd like to remove it, and I've verified that on x86_64-linux, GCL
> builds successfully with the default compiler.
> 
> In general, it would be good to include comments with rationale for
> workarounds like this, so that we have some idea of when the workaround
> can be removed, and what tests we must do to ensure that the original
> problem has been addressed.
> 
>      Thanks,
>        Mark

I looked through the commits and I'm not sure why I added gcc@4.9. When
did we change our default gcc from 4.9 to 5? I've made one attempt so
far at building on aarch64-linux without gcc@4.9 and I got a core-dump
but I haven't built it recently to see if it does that as-is.

I'll take a closer look at it and try to see what's up.


-- 
Efraim Flashner   <efraim@flashner.co.il>   אפרים פלשנר
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Re: Why is GCL built with gcc@4.9?

[Efraim Flashner]

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On Thu, Dec 13, 2018 at 10:33:48PM +0200, Efraim Flashner wrote:
> On Thu, Dec 13, 2018 at 12:03:59AM -0500, Mark H Weaver wrote:
> > Hi Efraim,
> > 
> > I'm curious about this commit of yours from April 2017:
> > 
> > --8<---------------cut here---------------start------------->8---
> > commit 5c7815f205e9164d4b82378de91bee7a65bcfbcb
> > Author: Efraim Flashner <efraim@flashner.co.il>
> > Date:   Mon Apr 10 05:20:09 2017 +0300
> > 
> >     gnu: gcl: Build with gcc@4.9.
> >     
> >     * gnu/packages/lisp.scm (gcl)[native-inputs]: Add gcc@4.9.
> > --8<---------------cut here---------------end--------------->8---
> > 
> > Do you remember why you did this?  There's no explanation in the
> > comments, nor in the commit log, nor in the 'bug-guix' or 'guix-devel'
> > email archives from around that time.
> > 
> > I'd like to remove it, and I've verified that on x86_64-linux, GCL
> > builds successfully with the default compiler.
> > 
> > In general, it would be good to include comments with rationale for
> > workarounds like this, so that we have some idea of when the workaround
> > can be removed, and what tests we must do to ensure that the original
> > problem has been addressed.
> > 
> >      Thanks,
> >        Mark
> 
> I looked through the commits and I'm not sure why I added gcc@4.9. When
> did we change our default gcc from 4.9 to 5? I've made one attempt so
> far at building on aarch64-linux without gcc@4.9 and I got a core-dump
> but I haven't built it recently to see if it does that as-is.
> 
> I'll take a closer look at it and try to see what's up.
> 

I tried compiling gcl with gcc@7 also and it still failed on aarch64.
The closest I have to a clue is that Debian's rule file has commented
out to use gcc@4.6, so I'm guessing that following our upgrade to
building with gcc@5 the package broke and it worked for a time with
gcc@4.9. Since it fails to build in any case on aarch64 and building
with gcc@5 doesn't cause any problems I'll go ahead and remove it.


-- 
Efraim Flashner   <efraim@flashner.co.il>   אפרים פלשנר
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted

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Re: Why is GCL built with gcc@4.9?

[Mark H Weaver]

Hi Efraim,

Efraim Flashner <efraim@flashner.co.il> writes:

> I looked through the commits and I'm not sure why I added gcc@4.9. When
> did we change our default gcc from 4.9 to 5?

The change was made on core-updates on 12 December 2016 (commit
b810a85019ab3c4ee1f889d0751b8eb06157dadc), and merged into master on
3 April 2017 (commit 2a0d5de5a9decd785b22dafa69aae5320231f1b7).  You
applied the workaround a week later.

> I'll take a closer look at it and try to see what's up.

I see that you recently removed the workaround.
Thanks for taking care of it.

    Regards,
      Mark