Bootstrap config: libgccjit libs dir

[antoyo]

r? @Kobzol

[rustbot]

This PR changes how GCC is built. Consider updating src/bootstrap/download-ci-gcc-stamp.

This PR modifies src/bootstrap/src/core/config.

If appropriate, please update CONFIG_CHANGE_HISTORY in src/bootstrap/src/utils/change_tracker.rs.

[rustbot]

Kobzol is not on the review rotation at the moment.
They may take a while to respond.

[antoyo]

@Kobzol: I'm sending this PR to gather some feedback from you or others.

How can I add tests for this new bootstrap config?
Where should I document this new config?

[bors]

☔ The latest upstream changes (presumably #149348) made this pull request unmergeable. Please resolve the merge conflicts.

[Kobzol]

I will focus on #149426 first, as I think that we should first deal with the compiler/cg_gcc side of things, before we go modify bootstrap.

[Kobzol]

This makes sense, although the implementation needs some changes. I'd be happy to play with this if you don't want to deal with doing these bootstrap changes.

View changes since this review

[bors]

☔ The latest upstream changes (presumably #149426) made this pull request unmergeable. Please resolve the merge conflicts.

[Kobzol]

I refactored the code a bit to more explicitly model that we have multiple target libgccjit dylibs per host, and also to enable both downloading from CI and using prebuilt libgccjit.so files (so that people don't also have to build their x64 libgccjit.so from scratch). Please let me know if it makes sense to you.

[antoyo]

Please let me know if it makes sense to you.

This commit makes sense to me.
For the other commit, I do not understand bootstrap enough to understand what's happening here. Would that commit help keep the m68k libgccjit.so file that was deleted? Do you want me to try to cross-compile rustc locally with that commit?

[Kobzol]

Do you want me to try to cross-compile rustc locally with that commit?

If you already have it prepared, yeah, you could try it. Although CI failed, so maybe there's something else wrong.

[antoyo]

If you already have it prepared, yeah, you could try it. Although CI failed, so maybe there's something else wrong.

Good. I try that right away.

[antoyo]

If you already have it prepared, yeah, you could try it. Although CI failed, so maybe there's something else wrong.

The command finished running and the issue with the m68k libgccjit.so file being deleted still seems there. Any ideas of how to fix this? Do the steps I posted above give you any hint?

[rustbot]

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo, @GuillaumeGomez

The rustc-dev-guide subtree was changed. If this PR only touches the dev guide consider submitting a PR directly to rust-lang/rustc-dev-guide otherwise thank you for updating the dev guide with your changes.

cc @BoxyUwU, @jieyouxu, @Kobzol, @tshepang

This PR modifies bootstrap.example.toml.

If appropriate, please update CONFIG_CHANGE_HISTORY in src/bootstrap/src/utils/change_tracker.rs.

[antoyo]

I added the error. Now this is ready for review.

I guess we should squash the commits since I made many back and forth since I didn't know how to implement this in the beginning.