ABI adjustment code for wasm doesn't handle 128bit ints and floats

[bjorn3]

According to https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md __int128 and long long double have to be returned indirectly. In

rust/compiler/rustc_target/src/callconv/wasm.rs

Lines 21 to 30 in 2776bdf

	fn classify_ret<'a, Ty, C>(cx: &C, ret: &mut ArgAbi<'a, Ty>)
	where
	Ty: TyAbiInterface<'a, C> + Copy,
	C: HasDataLayout,
	{
	ret.extend_integer_width_to(32);
	if ret.layout.is_aggregate() && !unwrap_trivial_aggregate(cx, ret) {
	ret.make_indirect();
	}
	}

however we are not doing .make_indirect() for i128 and f128. It currently works by accident as LLVM implicitly introduces a return area pointer when returning i128 and f128, but other backends and other code that needs to know the ABI may not be able to handle this.

[tgross35]

long long double

Assuming this is a typo in the spec? I don't know if this is valid. Unless they really want binary256...

[bjorn3]

I got confirmation on the tool-conventions PR that introduced this that it was indeed likely a mistake to write long long double instead of long double.

[tgross35]

(for my reference WebAssembly/tool-conventions#161 (comment))