[REQUEST] `mrustc` as alternative Rust compiler

[ojeda]

mrustc is a Rust compiler written in C++.

While it is mainly intended as a way to reduce the long bootstrap chain of rustc, it can compile some non-rustc code too.

[dkm]

I would like to work on this but I'm not familiar with mrustc yet.
What would be the better solution for using mrustc?
Initial guess would be:

$ make
$ make LIBS

Then I can use bin/mrustc with the freshly built libstd to compile simple examples.

How do you get the assembly output ? Also, I don't see any tag/release. Do you expect to have mrustc build daily from the master branch or is there some prebuild tarball available somewhere?

[ojeda]

How do you get the assembly output ?

I am not familiar with it either, but from what I understand, it is currently a transpiler to C without native codegen.

So I would have one entry in CE to show the C output; and perhaps another for that + GCC and/or + Clang.

Do you expect to have mrustc build daily from the master branch or is there some prebuild tarball available somewhere?

I think having a build from time to time when a major milestone is reached is enough for the moment (like when a newer Rust compiler version gets bootstrapped) . However, perhaps @thepowersgang would welcome nightlies nevertheless!

[dkm]

I've a setup working locally. I think it's easier to focus on upcoming releases and ignore anything earlier because that would need some workarounds (not hard, but not sure this is worth it). When a simple fix is merged, I'll start pushing PR here to add the compiler. As a first goal, I'll treat the C as the final product (I still need to see how to display this correctly). Maybe there will be something to chain this C into another compiler, but that's a different topic.

[dkm]

Hope to have everything correct here.
3 PR:

• 1 for supporting mrustc in CE + updated amazon config for rust part (haven't skipped the tests this time /o)
• builder script used to create a "packaged" mrustc for the github repository
• corresponding invocation to builder script in the infra nightly script to have it correctly build