llvm-devel: Support arm64

[ryandesign (Ryan Carsten Schmidt)]

The llvm ports say:

supported_archs i386 x86_64

Please investigate adding support for arm64.

[jeremyhu (Jeremy Huddleston Sequoia)]

We're not going to backport support for Apple Silicon Macs to older versions of llvm. This should be supportable when Apple upstreams our Apple Silicon work to llvm master. I'll check if that has been done.

[jeremyhu (Jeremy Huddleston Sequoia)]

Yep, upstreaming has happened, so we should be able to do this for -devel.

[ryandesign (Ryan Carsten Schmidt)]

Replying to jeremyhu:

We're not going to backport support for Apple Silicon Macs to older versions of llvm.

Then I suppose there might need to be some changes to the MacPorts base compiler selection process, so that it does not add old versions of clang to the fallback list on arm64 if they don't support arm64?

[kencu (Ken)]

yes, one of many changes, likely. Good thing, really, MP has kept up robust universal support, as that will be more easily leveraged to arm.

My immediate priority is to add in flang, so there is some method to compile fortan on ARM.

[michaelld (Michael Dickens)]

Looking forward to the arm64 support in llvm-devel ... as well as Ken's flang ... those are blockers for me right now getting UHD / Volk / GNU Radio to build on arm64. I can do some things with these ports, but not enough to be useful yet. Soon ... very soon ...

[kencu (Ken)]

the flang news is not looking optimistic in the short term at least; unfortunately it appears to be still in the nascent stages and is not yet emitting code.

[ryandesign (Ryan Carsten Schmidt)]

In e4b1bd41b6bfb4686661be85935ac3faed83fae2/macports-ports (master):

cctools: Use +xcode variant on arm

The llvm ports don't support arm yet.

See: #60941

[kencu (Ken)]

both llvm-11 and llvm-devel support arm64, and built packages are available on the packages website.