​​Rustbuild (All Hands 2019)
​​
​​Audience
​​Rustbuild maintainers (Alex, Mark); Potentially anyone — but will likely be somewhat low-level
​​When
​​Tuesday, 11:00-13:00, may wind down earlier
​​Where
​​Tomato
​​Meeting Style
​​Brainstorming/Discussion led by Mark
​​
​​

​​Summary

  • ​​Medium-term: LLVM will no longer need to be built locally (will use CI artifacts)
  • ​​needs windows
  • ​​Short-term: Non-rustc developers will no longer need to build rustc, LLVM
  • ​​Short-term: Rustc developers should predominantly be building rustc once
​​
​​The goal here is primarily to determine a plan for 2019 implementation/assistance for the below workflows. This is brainstorming in general.

​​Overall desires

  • ​​Avoid LLVM builds
  • ​​can likely do locally, probably don’t want to on CI
  • ​​copy libLLVM-8.0.so from CI to local builds
  • ​​Need to investigate dynamic libraries on Windows (currently libLLVM only built on linux)
​​

​​Stage renaming

  • ​​bootstrap compiler
​​
​​Now
​​Compiler
​​Artifacts
​​--cfg​
​​Compilation #1
​​downloaded/local
​​A
​​stage0
​​Compilation #2
​​A ( copied )
​​B
​​stage1
​​Compilation #3
​​B ( copied )
​​Routes:
  1. ​​B copied
  1. ​​C
​​stage2
​​
​​Future
​​Compiler
​​Artifacts
​​--cfg​
​​Compilation #1
​​downloaded/local
​​A
​​bootstrap (if previous version)
​​Compilation #2
​​A ( copied )
​​B
​​n/a
​​Compilation #3
​​B ( copied )
​​Routes:
  1. ​​B copied
  1. ​​C
​​n/a
​​x.py test --use-compiler={0,1,2}​
  • ​​0 = bootstrap
​​
  • ​​No one should be passing --use-compiler​ in general

​​Workflows

​​Compiler development
  • ​​Generally need std, test, but don’t want to wait to rebuild if possible
  • ​​Want pathway from change to src/librustc* to working compiler to be as fast as possible
​​
​​# can't be changing metadata, if you do, stop passing this option
​​# downloads CI artifacts for compiler 1
​​./configure --compiler-1-is-master
​​                                   
​​x.py build src/libtest
​​x.py test src/test/{run-pass...}
​​