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A comment on Firefox’s new streaming and tiering compiler. Parent comment

Re:Firefox’s new streaming and tiering compiler by Yoric on Wednesday January 17, 2018 @12:20PM (#16169726)
On the other hand, you could compile well-behaved subsets of JavaScript into wasm. Kind of what asm.js was doing.

Whether that's useful in practice is an open question, but it's plausible.

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Re:Firefox’s new streaming and tiering compiler by jahewson on Wednesday January 17, 2018 @12:31PM (#16169843)
It’s really inaccurate to call that “JavaScript” any more. You’re talking about a subset of JS that would never need to perform a GC! Really just “the subset of JavaScript which also happens to be C”.
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Re:Firefox’s new streaming and tiering compiler by sjrd on Wednesday January 17, 2018 @12:26PM (#16169783)
asm.js was not a well-behaved subset of JavaScript. It was a well-behaved subset of assembly that happened to be encoded in JavaScript.

There is virtually no human-written JS code that is amenable to compilation to wasm in a meaningful way. At the very least, you need a (mostly) sound type system to be able to compile to wasm with a positive expected ROI.

The speed of wasm comes in a large part from the fact that it is entirely statically typed, which means we don't need the speculative optimizations (and their deoptimization guards) all over the place.

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Re:Firefox’s new streaming and tiering compiler by Zekio on Thursday January 18, 2018 @06:29AM (#16176306)
Wonder if there will ever be a version of typescript that compiles to wasm
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Re:Firefox’s new streaming and tiering compiler by jahewson on Wednesday January 17, 2018 @12:41PM (#16169962)
Exactly, plus in a dynamic environment a tracing JIT can outperform AOT compiled code. This is true for both the JVM and .NET CLR, both mature platforms.
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