Add recipe for the LLVM SPIR-V back-end.

[maleadt]

To check if it's possible to move from https://github.com/KhronosGroup/SPIRV-LLVM-Translator to LLVM proper.

Doesn't need platform augmentations, because I'd like to simply use the latest version of the back-end possible. This works as long as we statically link libLLVM, but may still pose problems when there's IR incompatibilities that can't get auto-upgraded.

cc @vchuravy

[giordano]

You want to delete https://github.com/JuliaBinaryWrappers/SPIRV_LLVM_Backend_jll.jl/releases/tag/SPIRV_LLVM_Backend-v0.1.0%2B0 otherwise registration will fail

[maleadt]

Only loosely following LLVM's versioning here so that we can still make minor releases ourselves (e.g. containing Julia-specific patches).

[maleadt]

You want to delete https://github.com/JuliaBinaryWrappers/SPIRV_LLVM_Backend_jll.jl/releases/tag/SPIRV_LLVM_Backend-v0.1.0%2B0 otherwise registration will fail

Ah, good call. I accidentally deployed that by doing --deploy maleadt/SPIRV_LLVM_Backend_jll.jl, omitting the =...

I've just deleted the entire repo.

[maleadt]

Turns out the back-end from LLVM 19 is pretty unusable, so I'll bump this to 20 straight away (sorry for wasting some compute time here).

[maleadt]

ld64.lld: error: undefined symbol: __isPlatformVersionAtLeast

LLVM 20 failing to build?

[giordano]

Yggdrasil/S/SDL2/build_tarballs.jl

Lines 25 to 29 in 52fe346

	elif [[ "${target}" == aarch64-apple-* ]]; then
	# Link to libclang_rt.osx to resolve the symbol `___isPlatformVersionAtLeast`:
	# <https://github.com/libsdl-org/SDL/issues/6491>.
	export LDFLAGS="-L${libdir}/darwin -lclang_rt.osx"
	fi

[giordano]

For LLVM specifically, others have simply patched out the offending file:

Yggdrasil/C/Cling/bundled/patches/avoid_builtin_available.patch

Lines 1 to 13 in 52fe346

	diff --git a/lib/Support/Unix/Path.inc b/lib/Support/Unix/Path.inc
	index 27c8a1bc9b7..11f2cc518d0 100644
	--- a/lib/Support/Unix/Path.inc
	+++ b/lib/Support/Unix/Path.inc
	@@ -1201,7 +1201,7 @@ namespace fs {
	std::error_code copy_file(const Twine &From, const Twine &To) {
	uint32_t Flag = COPYFILE_DATA;
	#if __has_builtin(__builtin_available) && defined(COPYFILE_CLONE)
	- if (__builtin_available(macos 10.12, *)) {
	+ {
	bool IsSymlink;
	if (std::error_code Error = is_symlink_file(From, IsSymlink))
	return Error;

https://github.com/llvm/llvm-project/blob/ff8f6abe20a9dfbb1de8d978f865092413d3416c/llvm/lib/Support/Unix/Path.inc#L1490