feat(wasm-builder): add support for new wasm32v1-none target

[StackOverflowExcept1on]

Description

Resolves #5777

Previously wasm-builder used hacks such as -Zbuild-std (required rust-src component) and RUSTC_BOOTSTRAP=1 to build WASM runtime without WASM features: sign-ext, multivalue and reference-types, but since Rust 1.84 (will be stable on 9 January, 2025) the situation has improved as there is new wasm32v1-none target that disables all "post-MVP" WASM features except mutable-globals.

Previously, your rust-toolchain.toml looked like this:

[toolchain]
channel = "stable"
components = ["rust-src"]
targets = ["wasm32-unknown-unknown"]
profile = "default"

It should now be updated to something like this:

[toolchain]
channel = "stable"
targets = ["wasm32v1-none"]
profile = "default"

To build the runtime:

cargo build --package minimal-template-runtime --release

Integration

If you are using Rust 1.84 and above, then install the wasm32v1-none target instead of wasm32-unknown-unknown as shown above. You can also remove the unnecessary rust-src component.

Also note the slight differences in conditional compilation:

• wasm32-unknown-unknown: #[cfg(all(target_family = "wasm", target_os = "unknown"))]
• wasm32v1-none: #[cfg(all(target_family = "wasm", target_os = "none"))]

Avoid using target_os = "unknown" in #[cfg(...)] or #[cfg_attr(...)] and instead use target_family = "wasm" or target_arch = "wasm32" in the runtime code.

Review Notes

Wasm builder requires the following prerequisites for building the WASM binary:

• Rust >= 1.68 and Rust < 1.84:
  • wasm32-unknown-unknown target
  • rust-src component
• Rust >= 1.84:
  • wasm32v1-none target
  • no more -Zbuild-std and RUSTC_BOOTSTRAP=1 hacks and rust-src component requirements!

[github-actions]

Review required! Latest push from author must always be reviewed

[StackOverflowExcept1on]

How do I pass CI checks like SemVer and other?

[jasl]

Ping @bkchr It seems the CI won't trigger.

[jasl]

@StackOverflowExcept1on https://github.com/paritytech/polkadot-sdk/actions/runs/12674781431/job/35324397805?pr=7008 This required CI failed, could you fix it?

[StackOverflowExcept1on]

@jasl @bkchr I'll fix that in the next 30 minutes. Also wondering if we'll have to update the runners tomorrow, since the new version 1.84 will be stable tomorrow. I mean that the wasm32-unknown-unknown target should be replaced by wasm32v1-none on runners. We should come to something one on CI. Perhaps we should also replace all occurrences of “wasm32-unknown-unknown”.

[jasl]

@jasl @bkchr I'll fix that in the next 30 minutes. Also wondering if we'll have to update the runners tomorrow, since the new version 1.84 will be stable tomorrow. I mean that the wasm32-unknown-unknown target should be replaced by wasm32v1-none on runners. We should come to something one on CI. Perhaps we should also replace all occurrences of “wasm32-unknown-unknown”.

I'm not Parity staff, so I don't know...
I remember there was a critical accident in history by updating the Rust version, so I propose we not update CI.
Let Parity guys update their facilities.

[bkchr]

Actually I realized something, @StackOverflowExcept1on can we change the pr to make the new target optional? So, it should still accept the wasm32-unknown-unknown target, but print some warning.

[StackOverflowExcept1on]

@bkchr For now, do you want to use an environment variable like FORCE_NEW_WASM_TARGET to switch to wasm32v1-none and remove the warning?

[jasl]

Several required CI checks fail. Maybe the latest patch has trouble

[StackOverflowExcept1on]

@jasl I think it's some kind of problem with std hitting wasmv1-none (it doesn't support it). It may have happened after recent merge of master.