RISC-V support

[ViralBShah]

Opening an issue for RISC-V support. I couldn't find an existing issue. Discussed here: JuliaLang/julia#56105 (comment)

[eschnett]

I have a branch here https://github.com/eschnett/Yggdrasil/tree/eschnett/riscv64 where I started to add riscv64 support to Yggdrasil. It's not much to look at.

The branch will only work if you patch Julia to support riscv64 because Yggdrasil handles architectures via the built-in Julia mechanisms. Modern versions of Julia (1.12, maybe also 1.11) have that support. For Julia 1.7 you need to add a patch yourself.

[eschnett]

Here are some pull requests for work I did to support riscv64 in BinaryBuilder:

• Add riscv64 PlatformSupport BinaryBuilderBase.jl#374
• Support riscv64 platform BinaryBuilderBase.jl#375
• 0_RootFS: Support riscv64 #8468
• Support riscv64 BinaryBuilder.jl#1355
• Add riscv64 ELF symbols JuliaIO/ObjectFile.jl#47

Other related PRs:

• [AutoBuild] Don't allow building for riscv64 for old Julia BinaryBuilder.jl#1356
• Use tryparse to parse platform triplet JLLWrappers.jl#74
• [AutoBuild] Always require JLLWrappers v1.7.0 BinaryBuilder.jl#1357

[fingolfin]

Any particular reason why those three PR are not yet merged / should not be merged?

[giordano]

They wouldn't work with Julia v1.7.

[ViralBShah]

Is my understanding correct that the plan would be to move to BinaryBuilder 2 (which has some ways to go) and not plan on upgrading BB from 1.7 to a recent Julia version?

[giordano]

We can still make things work in v1.7 with some pirating, we discussed this with Tim some time ago and we're confident that this should work, but the above PRs as-are aren't sufficient. Side note, I'm trying to get access to some RISC-V systems, which should make testing much easier for me in the future.

[eschnett]

I think there are one or two functions in Julia Base that need to be patched for Julia 1.7 to support RISC-V. Is this what you're addressing by "pirating"?

[giordano]

Yeah.