[cfe-dev] [RFC] Make "requires arm" also include AArch64 in module map files

[Ben Langmuir]

> On Jul 23, 2015, at 2:08 AM, Renato Golin <renato.golin at linaro.org> wrote:
> 
> On 22 July 2015 at 04:24, Ben Langmuir <blangmuir at apple.com> wrote:
>> I propose that we rename the current “arm” feature to “arm32” and take over
>> the name “arm” to mean “arm32 || aarch64”.
> 
> I don't see anything wrong with this, and being a new thing, we have
> some degrees of freedom. But would be good to match what other
> toolchains are doing for the similar effect, or have a good reason not
> to. Especially related to names and what they mean. We don't want name
> nightmares in the future.

I agree. I looked around for some precedent here but didn’t find much.  Maybe someone who’s more familiar with this space knows of some?

For “arm”:
* The closest I found is that GCC has a function attribute "target(arm)” that means to use the “A32” ISA, but this is to distinguish it from thumb (T32), not from aarch64/A64 it looks like.
* I don’t think this should stop us from using “arm” to mean arm32 || arm64.

For “arm32”:
* I made this name up, and haven’t found any useful precedent for this or any other name.  The ISA is called A32, but I think the T32 ISA would also count as “arm32” in my scheme…
* Since no is actually asking for this feature, I suppose we could just not add it. Users who wanted arm32 could say “requires arm, !aarch64” for now and we could reconsider this once there is motivation

Ben


> 
> cheers,
> --renato