Stabilize parallel front end

[nikomatsakis]

Metadata
Owner(s)	@SparrowLii
Team(s)	compiler
Goal document	2024h2/parallel-front-end

Summary

We will move rustc's support for parallel front end closer to stability by resolving [ICE] and [deadlock] issues, completing the [test] suit for multithreaded scenario and integrating parallel front end into bootstrap. This fits into our larger goal of improving rustc build times by 20% by leveraging multiple cores and enhance its robustness.

Tasks and status

• Implementation (@SparrowLii)
• Author tests (@SparrowLii)
• Discussion and moral support (compiler )

[nikomatsakis]

This issue is intended for status updates only.

For general questions or comments, please contact the owner(s) directly.

[SparrowLii]

• Key developments: *
  Use ui test to locate and solve the ICE problem of parallelfront end
  Discussed strategies for customizing and enhancing the compiler testing suit to address hard-to-reproduce bugs
• Blockers: 
  Many deadlock issues are difficult to reproduce and resolve
• Help wanted:
  Help test the deadlock code in the issue list and try to reproduce the issue