POC: Shrinking generated binary

[Acaccia]

This is a POC trying to reduce the size of the generated binary.

The main issue in the generated binary is that the entire standard lib is copied inside.
As proposed in #119, I tried using wasm-opt, but not on the standard lib but on the generated Wasm.
It also has the advantage of applying other optimizations, like inlining, or precompute compile-time evaluatable expressions.

It works for small examples, such as (+ 2 2), which results in a Wasm that contains the int 4 immediately. No more standard lib, and the result is precomputed.

However, for most of our tests, it's a failure. It seems wasm-opt fails to parse our generated Wasm. It needs more investigations...

[Acaccia]

So the problem is that binaryen (which contains the tool wasm-opt) supports only s-expressions in Webassembly code. So something like this is not understood:

(func $foo (export "foo") (local i32)
        (i32.const 1)
        (local.set 0)
    )

This kind of syntax is used extensively in our code generation. The simple assignment of a clarity value to wasm variables for example works like this.

[cylewitruk]

So the problem is that binaryen (which contains the tool wasm-opt) supports only s-expressions in Webassembly code. So something like this is not understood:

(func $foo (export "foo") (local i32)
        (i32.const 1)
        (local.set 0)
    )

This kind of syntax is used extensively in our code generation. The simple assignment of a clarity value to wasm variables for example works like this.

What happens if you compile the WAT and then decompile it? Maybe it outputs in the "understood" format?

[Acaccia]

@cylewitruk

What happens if you compile the WAT and then decompile it?

No sadly, this is not how it works. You don't really compile Wat, you translate it to Wasm.
But yes, I'm looking for tools to convert the generated Wasm to s-expressions, I think it's the way to go if we don't want to make a serious reorganization of the generator.

[Acaccia]

it seems I made a false assumption. I tried compiling Wat using wasm-as, their webassembly compiler, and assumed that the compilation error would be the same as wasm-opt. It seems it's not the case, and code that does not compile with wasm-as but that compiles with wat2wasm can sometimes use wasm-opt, sometimes not. It still needs more investigation.