Comment by AceJohnny2
2 years ago
In contrast: "How Swift Achieved Dynamic Linking Where Rust Couldn't " (2019) [1]
On the one hand I'm disappointed that Rust still doesn't have a calling convention for Rust-level semantics. On the other hand the above article demonstrates the tremendous amount of work that's required to get there. Apple was deeply motivated to build this as a requirement to make Swift a viable system language that applications could rely on, but Rust does not have that kind of backing.
It's only fair to point out that Swift's approach has runtime costs. It would be good to have more supported options for this tradeoff in Rust, including but not limited to https://github.com/rust-lang/rfcs/pull/3470
Notably these runtime costs only occur if you’re calling into another library. For calls within a given swift library, you don’t incur the runtime costs: size checks are elided (since size is known), calls can be inlined, generics are monomorphized… the costs only happen when you’re calling into code that the compiler can’t see.