What's the expected final toolchain for C -> Wasm? If I understand correctly, there are at least two competing backends (upstream llvm, emscripten-fastcomp), as well as several paths through binaryen (s2wasm, asm2wasm)... and Binaryen seems to have forked the textual format when 0xc landed, and in a way that won't necessarily round-trip. Which puts me in a place of grokking the binary format and the WebAssembly.* DOM APIs, but not the toolchain to actually get there.
1. The llvm wasm backend is upstream, which is good.
2. asm2wasm will likely stay better at compile times, especially for non-separate compilation (which is important for code size, which matters a lot on the web).
3. We don't know which of the two will produce better/smaller code. The wasm backend isn't ready for a fair comparison yet. And there are reasons to guess both ways here.
So we might not end up with a single "final" toolchain. Different people in the toolchain space have different ideas of what will work best, so I guess we'll just see how things turn out. And it's possible everyone will be right in the sense that different toolchains will be better at a different use cases.
