Meeting 2020-10-01

[repi]

Previous meeting: #35

Initial agenda (please edit and add)

• Prototype compiler update - @khyperia
• Relooper update SPIRV-Tools Relooper Implementation (SCF) #24 @VZout
  • Possibly split up the "control flow ops" part of the structurizer? Good first issue?
• What is needed for our Q4 objective of getting Convert all Ark shaders to Rust GPU #36 up? - @khyperia
  • biggest rustc_codegen_spirv issues remaining are Add bindings for spirv-opt #31, Capability computation UX #42, Convert panics to compiler errors #43, Zombies in non-core code should be compiler errors, not zombies #44, GPU-side layout/binding attributes #45.
    • Some of these aren't required for the Q4 objective, but will be needed soon after anyway.
• Pod structure and roles - @repi

[repi]

Meeting notes

Participants

• @repi
• @khyperia
• @VZout
• @Jasper-Bekkers

Minutes

Status update

Codegen - @khyperia

• First hello world triangle shader up!! Running in modified ash example.

• Required manually do what spirv-opt supposed to be doing otherwise crashed Nvidia driver

• spriv-opt is broken :( spirv-opt ssa-rewrite produces code that fails the validator KhronosGroup/SPIRV-Tools#3873

• spirv-val is also broken. Currently tracked in the same issue as the spirv-opt issue, may split off a new issue if spirv-tools folks want to.

• Decent amount of Ark shaders (Convert all Ark shaders to Rust GPU #36) does not need the structurizer (SPIRV-Tools Relooper Implementation (SCF) #24), which is nice and makes things easier as it doesn't need the structurizer now directly

Structurizer (#24) - @VZout

• if chains working properly!
• Now working on break, quite tricky
• At least a few weeks of work left
• Could use some help on the task of inserting OpSelectionMerge and OpLoopMerge instructions, unclear who could help though?
  • Reasonably separate task from the main structurization pass, could be worked on in parallel
  • Good task for anyone that want to learn compilers

Q4 objective (#36) feasibility?

• To convert most Ark shaders to Rust and use the compiler in Ark.

• Plenty of issues, but for Ark not all of them need to be fixed

• Do our "Go or No Go" meeting next thursday, main focus in that meeting

  • Very likely we will continue ("go"), but need to map out scope and align
  • Discuss & reiterate why this project actually would be useful, what are our goals
  • Have participants from the wider team, including @arirawr
  • What do we need to go ahead and how would it work? crates.io publishing, build.rs building?, custom rustc distribution
  • Who / how many do we need?
    • Already feel need help in 2 areas: compiler engineering, and general Rust / build systems.
    • @MarnixKuijs may be able to help soon, likely interested
    • @repi and @Jasper-Bekkers to investigate and think about additional people and options, could do contracts, sponsorships or full-time
  • Define Rust GPU capabilitiy levels and commit to each level at a time
    • Examples
    • Level 1 = hello world shader (today!)
    • Level 2 = Ark shaders in ark, with deployed rust compiler
    • Level 3 = generally userful for other projects, graphics std, more shader features
    • @khyperia file issue and flesh out more about first levels
  • Further map out project & issues ahead of time before the meeting and summarize in agenda for it - @repi @Jasper-Bekkers @khyperia

Other topics

• Clarified team structure and roles

  • @khyperia = Pod lead (responsible), drive technical work with code, issues, and people. Mostly internal focused
  • @Jasper-Bekkers = Ark objective owner (accountable). Mostly focused toward project overall and externally, hands on tech help

• @Jasper-Bekkers thinking to attending Khronos SPIR meeting next week to check out how it works and evangalize a bit

• Only Traverse is Khronos member (so Embark folks can't attend SPIR meeting), Embark likely should join eventually also