Tracking issue for -Z instrument-xray

[ilammy]

This is a tracking issue for -Z instrument-xray flag, enabling XRay instrumentation support.

• Docs: TBD
• MCP: -Z instrument-xray option compiler-team#561

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

• Implement the feature
• Adjust documentation (see instructions on rustc-dev-guide)
• Stabilization PR (see instructions on rustc-dev-guide)

Unresolved Questions

• Do we want to stabilize this at all? That will be know after the unstable option sees some use.

Implementation history

• Add -Z instrument-xray flag #102963

[csmoe]

https://maskray.me/blog/2023-06-18-port-llvm-xray-to-apple-systems xray was ported to mac recently, should we enable it on those targets? And maybe we should bundle the llvm xray runtime as asan/tsan along with rustup.