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What does that have to do with a non-browser interpreter? I think you might've responded to the wrong post.

by AgentME 10y ago

kibwen 10y ago
I believe I've responded to the right post. :) Currently, WASM (and Javascript, when JIT'ed) are lowered to Cretonne IR, which is then optimized and translated to native code by the Cretonne engine, which is then executed by Spidermonkey. What the link above is proposing is to extract Cretonne into a standalone component capable of producing object files which can be linked into other programs as expected. The Rust project would intend to use such a backend by writing a pass to translate Rust to Cretonne IR. However, the important observation is that WASM and Javascript are already being translated to Cretonne IR, which means that if the Rust developers do the work of creating a standalone backend out of Cretonne, then WASM and Javascript should be able to leverage it to produce code that's independent of the browser (though for JS you'd probably need to implement some additional external runtime support).
- AgentME 10y ago
  So Rust is considering making a general backend which compiles to WASM first and then compiling that to native code, which could be faster and means that they would be creating a general WASM->native compiler in the process? That sounds pretty useful and clever if I'm getting it right.
  - kibwen 10y ago
    You're close (it's tricky to follow all these things feeding into all these other things). What they have right now is a prototype WASM -> IR -> pseudo-native code compiler (producing code only fit for being directly executed by a JS VM). What they're proposing is to flesh out the native code backend so that its output can be fed into the usual platform-native compiler toolchains. Then, they'd modify the Rust compiler to be able to produce the IR that this project (Cretonne) operates upon (which may be similar to, but is not precisely, WASM). So Rust would not be producing WASM directly, it would be producing code that is conceptually one level "below" WASM, but still one level above machine code. And yes, in the process this work would also enable the lower levels of a platform-native WASM toolchain.

What does that have to do with a non-browser interpreter? I think you might've responded to the wrong post.

by AgentME 10y ago

What does that have to do with a non-browser interpreter? I think you might've responded to the wrong post.

I believe I've responded to the right post. :) Currently, WASM (and Javascript, when JIT'ed) are lowered to Cretonne IR, which is then optimized and translated to native code by the Cretonne engine, which is then executed by Spidermonkey. What the link above is proposing is to extract Cretonne into a standalone component capable of producing object files which can be linked into other programs as expected. The Rust project would intend to use such a backend by writing a pass to translate Rust to Cretonne IR. However, the important observation is that WASM and Javascript are already being translated to Cretonne IR, which means that if the Rust developers do the work of creating a standalone backend out of Cretonne, then WASM and Javascript should be able to leverage it to produce code that's independent of the browser (though for JS you'd probably need to implement some additional external runtime support).

AgentME 10y ago
So Rust is considering making a general backend which compiles to WASM first and then compiling that to native code, which could be faster and means that they would be creating a general WASM->native compiler in the process? That sounds pretty useful and clever if I'm getting it right.
- kibwen 10y ago
  You're close (it's tricky to follow all these things feeding into all these other things). What they have right now is a prototype WASM -> IR -> pseudo-native code compiler (producing code only fit for being directly executed by a JS VM). What they're proposing is to flesh out the native code backend so that its output can be fed into the usual platform-native compiler toolchains. Then, they'd modify the Rust compiler to be able to produce the IR that this project (Cretonne) operates upon (which may be similar to, but is not precisely, WASM). So Rust would not be producing WASM directly, it would be producing code that is conceptually one level "below" WASM, but still one level above machine code. And yes, in the process this work would also enable the lower levels of a platform-native WASM toolchain.