[Buildroot] [Bug 9876] New: aarch64 support with gcc 4.8 toolchain

[Buildroot] [Bug 9876] New: aarch64 support with gcc 4.8 toolchain

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=9876

            Bug ID: 9876
           Summary: aarch64 support with gcc 4.8 toolchain
           Product: buildroot
           Version: 2017.02
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P5
         Component: Other
          Assignee: unassigned at buildroot.uclibc.org
          Reporter: jpcartal at free.fr
                CC: buildroot at uclibc.org
  Target Milestone: ---

Hello,

I'm trying to compile for the aarch64 architecture using an external gcc 4.8
toolchain.
However I get the following error :
>>> toolchain-external-custom  Installing to staging directory
/usr/bin/install -D -m 0755
/home/jpcartal/Dev/Ssd/buildroot/buildroot-2017.02/N30_test/build/toolchain-external-custom/toolchain-wrapper
/home/jpcartal/Dev/Ssd/buildroot/buildroot-2017.02/N30_test/host/usr/bin/toolchain-wrapper
aarch64-linux-gcc: error: unrecognized command line option '-mabi=lp64'

My understanding is that the mabi=lp64 option is only available on gcc 4.9.x
and newer.

Is there any solution available to compile for aarch64 architecture with a gcc
4.8.x toolchain ?

Thanks for your help.

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[Buildroot] [Bug 9876] aarch64 support with gcc 4.8 toolchain

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=9876

Peter Korsgaard <jacmet@uclibc.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #1 from Peter Korsgaard <jacmet@uclibc.org> ---
(In reply to Jean-pierre Cartal from comment #0)

You could remove the lp64 line from arch/Config.in.arm, but considering how old
gcc 4.8 is compared to aarch64, does it really make sense to use such an old
toolchain?

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[Buildroot] [Bug 9876] aarch64 support with gcc 4.8 toolchain

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=9876

--- Comment #2 from Jean-pierre Cartal <jpcartal@free.fr> ---
Hi,

Thanks for your help.

Unfortunately we don't have much choice regarding the toolchain version as it
is currently provided by a 3rd party. We might try to use buildroot toolchain
since that would indeed solve our issue. Thanks for the tip on where to remove
the lp64 option.

As a side note, wouldn't it make sense to disable aarch64 compilation with
external gcc  toolchains older than 4.9.x since it will not work ?

Regards.

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[Buildroot] [Bug 9876] aarch64 support with gcc 4.8 toolchain

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=9876

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |WONTFIX
             Status|ASSIGNED                    |RESOLVED

--- Comment #3 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
For custom external toolchains, we simply let the user specify which gcc
version the toolchain uses, and check that at the beginning of the build. We
don't try to prevent the user from using an unsupported gcc version depending
on the selected architecture, and I don't think we want to go down this route.
Especially since custom external toolchain quite often use vendor-specific gcc
versions that are patched to support additional features/processors, and
unnecessarily restricting the set of gcc versions to use would not be very
nice. For example, a patched gcc 4.8 could very well support lp64.

So I don't think we'll try to solve this problem.

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[Buildroot] [Bug 9876] aarch64 support with gcc 4.8 toolchain

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=9876

Yann E. MORIN <yann.morin.1998@free.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |yann.morin.1998 at free.fr

--- Comment #4 from Yann E. MORIN <yann.morin.1998@free.fr> ---
We don't try to prevent the user from using an unsupported gcc version
depending on the selected architecture, and I don't think we want to go down
this route.

So I don't think we'll try to solve this problem.

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[Buildroot] [Bug 9876] aarch64 support with gcc 4.8 toolchain

[Yann E. MORIN]

On 2017-05-25 13:21 +0000, bugzilla at busybox.net spake thusly:
> https://bugs.busybox.net/show_bug.cgi?id=9876
> 
> Yann E. MORIN <yann.morin.1998@free.fr> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |yann.morin.1998 at free.fr
> 
> --- Comment #4 from Yann E. MORIN <yann.morin.1998@free.fr> ---
> We don't try to prevent the user from using an unsupported gcc version
> depending on the selected architecture, and I don't think we want to go down
> this route.
> 
> So I don't think we'll try to solve this problem.

Woops... It seems I was not fast enough to cancel my reply after I
accidentally hit "apply changes" in the tracker. Sorry...

Regards,
Yann E. MORIN.

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[Buildroot] [Bug 9876] aarch64 support with gcc 4.8 toolchain

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=9876

--- Comment #5 from Yann E. MORIN <yann.morin.1998@free.fr> ---
> We don't try to prevent the user from using an unsupported gcc version
> depending on the selected architecture, and I don't think we want to go
> down this route.
> So I don't think we'll try to solve this problem.

Agreed.

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