asm2wasm: disable mutable globals

[mnater]

Hi

Since asm.js requires globals to be mutable asm2wasm converts all imported globals to mutable globals (https://github.com/WebAssembly/binaryen/blob/master/src/asm2wasm.h#L922).

This is not necessary if the imported globals isn't reassigned a new value. I don't reassign values to imported globals (and if so I'd copy the value to a local variable). Is there a way to disable this assignment upon compiling from asm2wasm or when optimizing code?

[kripken]

Thanks, we should add a pass that optimizes stuff like that. If no one else is interested I can write it.

[kripken]

#2066 implements this. Please test to see if it does what you expect @mnater

[mnater]

Hi kripken

Great. #2066 does exactly what I was looking for.
Thanks for this awesome work.

[kripken]

Great, thanks @mnater, I'll try to land it later today then.