Rust meets Mobile

2022 BazelCon talk about using bazel to build rust libraries for iOS and Android

Transcript

1. Rust meets Mobile Keith Smiley (he/him) Principal Engineer, Lyft @SmileyKeith
2. Sharing code on mobile
3. Why rust?
4. Rust + bazel
5. rust_library( name = "foo", srcs = ["foo.rs"], ) swift_library( name = "main", srcs = ["main.swift"], deps = [":foo"], ) ios_application(...) Shouldn't this work?
6. --platforms=//:ios_arm64
7. bazel#7260
8. platform_mappings
9. flags: --cpu=arm64-v8a --crosstool_top=//external:android/crosstool //:android_aarch64 --cpu=ios_arm64 --apple_platform_type=ios //:ios_arm64 ...
10. Undefined symbols for architecture arm64: "___rust_alloc", referenced from: ... "___rust_alloc_error_handler", referenced from: ... ... rules_rust#1238 / rust#73632
11. Who does the linking?
12. How do I use it?
13. #[no_mangle] pub extern fn print_something_from_rust() { println!("Ferris says hello!"); } #[no_mangle] pub extern fn get_a_value_from_rust() -> i32 { 42 } extern void print_something_from_rust(void); extern int32_t get_a_value_from_rust(void);
14. #[no_mangle] pub extern "system" fn Java_com_example_androidapp_JniShim_getValue() -> i32 { get_a_value_from_rust() } package com.example.androidapp; public class JniShim { public static native int getValue(); }
15. dtolnay/cxx rust-lang/rust-bindgen
16. Future areas of improvement
17. Developer Experience
18. Future rust mobile support
19. Was it worth it?
20. keith/bazel-rust-mobile-demo
21. - bazel#11454 - bazel#15041 - bazel#15248 - bazel#15462 - bazel#7260 - cargo-raze#484 - cargo-raze#489 - rules_rust#1186 - rules_rust#1238 - rules_rust#1259 - rules_rust#1271 - rules_rust#1276 - rules_rust#1290 - rules_rust#1304 - rules_rust#1362 - rules_rust#1372 - rules_rust#1401 - rules_rust#1462 - rules_rust#1541 - rules_rust#1545 - rules_rust#1546 - rules_rust#1573 - rules_rust#1576 - rust#73632
22. Thank you! twitter.com/SmileyKeith