[BOLT] Add AArch64 worker and builder

[paschalis-mpeis]

No description provided.

[paschalis-mpeis]

Hey folks,

This PR is part of introducing an AArch64 BOLT buildbot.

I have a couple of questions to @gkistanova:

(1) The worker name bolt-worker-aarch64 would recycled after PR #459 is merged. Or should we use a different name?

Specifically, could reusing Meta's former AArch64 buildbot name cause issues in the staging/master buildbot database?

(2) In the docs, the Steps To Add Builder To LLVM Buildbot section advices buildbot version 2.8.4, while Testing a Builder Config Locally version 3.11.7. Is the latter specific to local config testing, or should we pump the version on the guide?

Thanks in advance,
Paschalis

[aaupov]

Thank you for setting up an official BOLT AArch64 testing!

[paschalis-mpeis]

Forced pushed and rebased on top of #480, which does some cleanup and a few improvements in some edge case handling. No code changes in this rebase.

[vvereschaka]

Hi @paschalis-mpeis ,

just curious, is there any plans to launch the cross builders for BOLT, such as Linux/Win x86_64 => Linux/Aarch64 or similar?

Thanks,

[paschalis-mpeis]

Hi @vvereschaka,

Thanks for your interest! I captured the scope of this on Discourse:

• Adding AArch64 BOLT Buildbot and Improving Testing

This buildbot focuses on validating the BOLT AArch64 backend on Linux (Ubuntu 24). That said, it also builds a few additional targets though coverage for those is limited. I'm not sure if this fully answers your question. Let me know if otherwise.

BOLT will also be shipped as part of our ATfL toolchain, and we intend to run nightly tests on the supported Linux platforms (cc: @pawosm-arm).

[gkistanova]

LGTM.