Consider removing useless -sign-ext flag in substrate-wasm-builder

[StackOverflowExcept1on]

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• This is not a support question.

Motivation

https://github.com/rust-lang/blog.rust-lang.org/blob/4a72d620768932213baf39b03c6f1e61c00cd038/posts/2024-08-26-webassembly-targets-change-in-default-target-features.md

Request

Should be removed here

polkadot-sdk/substrate/utils/wasm-builder/src/wasm_project.rs

Lines 836 to 842 in c8d5e5a

	let mut rustflags = String::new();
	match target {
	RuntimeTarget::Wasm => {
	rustflags.push_str(
	"-C target-cpu=mvp -C target-feature=-sign-ext -C link-arg=--export-table ",
	);
	},

Solution

No response

Are you willing to help with this request?

Maybe (please elaborate above)

[bkchr]

Do you have a little bit more context?

[StackOverflowExcept1on]

@bkchr Rust 1.82 (stable Oct 17) enables multi-value and reference-types by default. I think it makes sense to additionally disable these features.

[nazar-pc]

According to link you have provided -C target-cpu=mvp is already sufficient to disable all of these features, not sure why Substrate also has -C target-feature=-sign-ext given that same document explicitly mentions that it'll be disabled for mvp CPU.

[StackOverflowExcept1on]

Yep, maybe it make sense just leave -C target-cpu=mvp since Rust added more documentation about this stuff

[bkchr]

not sure why Substrate also has -C target-feature=-sign-ext given that same document explicitly mentions that it'll be disabled for mvp CPU.

Apparently it did not worked before: paritytech/substrate#13804 (comment)

AFAIR we also just disabled this feature because there were issues with our wasm parser and not because we didn't wanted this feature.

CC @koute