YJIT: Dive into Ruby's JIT compiler written in Rust / Rust.Tokyo 2022

Transcript

1. YJIT: Dive into Ruby's JIT compiler written in Rust @k0kubun

   / Rust.Tokyo 2022

2. Me • @k0kubun • Shopify ◦ YJIT team • Ruby

   committer ◦ MJIT maintainer

3. What’s YJIT?

4. None
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8. How does YJIT work?

9. How YJIT works Ruby code

10. How YJIT works 1 + 2 Parse Ruby code Abstract

    Syntax Tree

11. How YJIT works 1 + 2 Parse Ruby code Abstract

    Syntax Tree putobject 1 putobject 2 opt_plus leave Compile Bytecode

12. How YJIT works 1 + 2 Parse Ruby code Abstract

    Syntax Tree putobject 1 putobject 2 opt_plus leave Compile JIT Bytecode Machine code

13. How YJIT works putobject 1 putobject 2 opt_plus leave JIT

    ? Machine code Bytecode

14. How YJIT works: Ruby 3.1 putobject 1 putobject 2 opt_plus

    leave x86_64 Codegen Machine code Bytecode

15. How YJIT works: Ruby 3.2 putobject 1 putobject 2 opt_plus

    leave Machine code Bytecode

16. How YJIT works: Ruby 3.2 putobject 1 putobject 2 opt_plus

    leave Machine code Bytecode

17. Lazy Basic Block Versioning

18. Lazily compile basic blocks

19. getlocal a getlocal b opt_plus setlocal c getlocal c putobject

    1 opt_gt branchunless getlocal a leave getlocal b leave Lazily compile basic blocks

20. Lazily compile basic blocks

21. getlocal a getlocal b opt_plus setlocal c getlocal c putobject

    1 opt_gt branchunless Branch stub Branch stub Lazily compile basic blocks

22. getlocal a getlocal b opt_plus setlocal c getlocal c putobject

    1 opt_gt branchunless getlocal a leave Branch stub Lazily compile basic blocks

23. getlocal a getlocal b opt_plus setlocal c getlocal c putobject

    1 opt_gt branchunless getlocal a leave Branch stub Lazily compile basic blocks

24. getlocal a getlocal b opt_plus setlocal c getlocal c putobject

    1 opt_gt branchunless getlocal a leave getlocal b leave Lazily compile basic blocks

25. Why lazy compilation? 1. Better code locality a. Only compile

    used paths b. Related code is put together

26. Why lazy compilation? 1. Better code locality a. Only compile

    used paths b. Related code is put together 2. More type information

27. Type Profiling

28. Type Profiling getlocal a getlocal b opt_plus

29. Type Profiling getlocal a getlocal b opt_plus

30. Type Profiling getlocal a getlocal b jmp regenerate

31. Type Profiling getlocal a getlocal b jmp regenerate

32. Type Profiling getlocal a getlocal b jmp regenerate a: 1

    b: 2

33. Type Profiling getlocal a getlocal b opt_plus (int) setlocal c

    getlocal c putobject 1 opt_gt branchunless

34. Passes • CodeGen -> Split -> Alloc Regs

35. Passes • CodeGen -> Split -> Alloc Regs

36. IR

37. IR Split

38. IR Split Alloc Regs

39. Rust Challenges

40. Clang and Bindgen Clang dependency or Per-architecture codegen?

41. Mutable Borrow

42. Next steps • Code GC • Register allocation • Method

    inlining

43. Conclusion • We reviewed the architecture of YJIT • Rust

    has been useful for transforming IR