[LLVMdev] Generate code for ARM Cortex m0, m3, and m4.

[Jan Hoogerbrugge]

Hi,

I am trying to cross compile code for ARM Cortex m0, m3, and m4.

For m0, I use:

-target armv6--eabi -mcpu=cortex-m0

That seems to work. For m3 and m4, I use the following which does not work
(fatal error: error in backend: CPU: 'cortex-m3' does not support ARM mode):

-target armv7m--eabi -mcpu=cortex-m3

and

-target armv7em--eabi -mcpu=cortex-m4

Who can help me with the right command line arguments for m3 and m4?

Thanks,
Jan


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[Jim Grosbach]

Add -mthumb. It’s also probably a bug in the driver that that’s required. It should be implied by the v7m triple and/or cpu. Mind filing a PR to that effect?

-Jim

[Amara Emerson]

Hi Jan,

For Cortex-M0, you should probably use the armv6m string in the target triple. For M3 and M4 you need to use the thumbv7m arch string, -mthumb won't be necessary.

Amara

[Renato Golin]

On 12 October 2013 23:00, Amara Emerson <amara....@gmail.com> wrote:

Hi Jan,

For Cortex-M0, you should probably use the armv6m string in the target triple. For M3 and M4 you need to use the thumbv7m arch string, -mthumb won't be necessary.

Yes, but I agree with Jim that a bug must be filled.

Jan, would you mind filling a bug?

http://llvm.org/bugs/enter_bug.cgi?product=clang

cheers,

--renato

[Bernard Ogden]

I've got a trivial fix for this problem, and another one which manifests when thumb is given without an explicit CPU. I'll start pushing it through our submissions process.

[Renato Golin]

Thanks Bernie,

Feel free to assign yourself to the bug report, just so we know someone is working on it.

cheers,

-renato

[Jim Grosbach]

I see you already found it, but for others following along, this is http://llvm.org/bugs/show_bug.cgi?id=17559.

-Jim