Automatic gcc/clang compiler installation

[aminya]

Provide gcc/clang compiler through JIL packages or BinaryProvider or BinaryBuilder.

https://github.com/JuliaPackaging/Yggdrasil/issues/17

Discussion in Slack: https://julialang.slack.com/archives/C674ELDNX/p1575110827223000 https://julialang.slack.com/archives/CB8A1RNCE/p1575316088173300

For more robust compiling across platforms, PackageCompilerX is a good place to look.

[tshort]

Here's a try that Kristoffer made for Clang: https://github.com/KristofferC/Clang_jll.jl

According to discussions on the static_compilation channel on Slack, he ran into problems on Windows.

[aminya]

Matlab automatically installs MinGW for Windows over the internet. The PR I made was using this toolchain

[tshort]

LLVM/Clang is getting close now (https://github.com/JuliaPackaging/Yggdrasil/pull/296). It is still failing on some platforms, though. That also gives us a linker (lld) which is helpful for WebAssembly.

[aminya]

LLVM recipe is merged. Should we use it now?

[aminya]

There is no Artifacts.toml yet https://github.com/JuliaBinaryWrappers/LLVM_jll.jl/ Run: https://dev.azure.com/JuliaPackaging/Yggdrasil/_build?definitionId=1&_a=summary

[tshort]

When it's ready, it's worth trying.

One tricky thing might be pulling the same version of LLVM that Julia is currently running. (And for WebAssembly, the higher version of LLVM, the better.)

[aminya]

So Artifacts are up: https://github.com/JuliaBinaryWrappers/LLVM_jll.jl/

[aminya]

@tshort is the new PackageCompiler (formerly known as X) useful for StaticCompiler?

[tshort]

The new PackageCompiler is an alternative approach to doing the same thing. Some comparisons:

PackageCompiler

• Mature
• Works with a wide range of code
• Huge library output (needs tree shaking to reduce size)
• Can't cross compile (I think)

StaticCompiler

• Immature
• Works with a narrow range of code
• Small output
• Can cross compile

[aminya]

Yes, so can't we reuse some code from PackageCompiler to enhance the StaticCompiler? At least, PackageCompiler now installs gcc on Windows automatically.

[tshort]

Should be possible. We're already using some of their code.