arm64 versus aarch64 in LLVM.default_target_triple

[HertzDevil]

This spec is still failing on my M2:

crystal/spec/std/llvm/llvm_spec.cr

Lines 15 to 18 in 25d3303

	it ".default_target_triple" do
	triple = LLVM.default_target_triple
	{% if flag?(:darwin) %}
	triple.should match(/-apple-macosx$/)

Failures:

  1) LLVM .default_target_triple
     Failure/Error: {% if flag?(:darwin) %}

       Expected: "arm64-apple-darwin23.1.0"
       to match: /-apple-macosx$/

     # spec/std/llvm/llvm_spec.cr:17

LLVM is supposed to normalize the triple by removing the version number, but this doesn't work because the triple starts with arm64 rather than aarch64:

crystal/src/llvm.cr

Lines 91 to 99 in 25d3303

	def self.default_target_triple : String
	chars = LibLLVM.get_default_target_triple
	case triple = string_and_dispose(chars)
	when .starts_with?("x86_64-apple-macosx"), .starts_with?("x86_64-apple-darwin")
	# normalize on `macosx` and remove minimum deployment target version
	"x86_64-apple-macosx"
	when .starts_with?("aarch64-apple-macosx"), .starts_with?("aarch64-apple-darwin")
	# normalize on `macosx` and remove minimum deployment target version
	"aarch64-apple-macosx"

This spec passes inside a Nix shell. I don't know what is going on there.

Rust had this problem too. Apparently arm64 is preferred over aarch64 now?

[miry]

I found the same thing, that LLVM supports name arm64-apple-darwin, the aarch64-apple-darwin could be replaced. (llvm-config --host-target #=> arm64-apple-darwin23.0.0)

in crystal-lang/distribution-scripts#268