Failed to build some contracts with rustc 1.70

[kvinwang]

 [2/4] Post processing code
ERROR: Loading of original wasm failed

Caused by:
    0: Loading of wasm module at '[...]/target/ink/wasm32-unknown-unknown/release/system.wasm' failed
    1: Unknown opcode 192

The failed contract is here: https://github.com/Phala-Network/phala-blockchain/tree/master/crates/pink-drivers/system

[kvinwang]

There is an upstream discussion: rust-lang/rust#109807

[ascjones]

@kvinwang thanks for reporting this we will look into it. Regarding the linked issue,cargo-contract does not explicitly pass target-feature=-sign-ext, so is the issue linked relevant (although I haven't read it properly all the way through)? I'm not an expert in these Wasm features so need to look at this to understand it better.

[kvinwang]

so is the issue linked relevant (although I haven't read it properly all the way through)?

Yep, it is relevant. I can also reproduce the example in that issue with:

RUSTFLAGS="-C linker-plugin-lto -C target-cpu=mvp" cargo build --target wasm32-unknown-unknown --release -Z build-std=std,panic_abort -Z build-std-features=panic_immediate_abort --no-default-features

where -C linker-plugin-lto is used by cargo-contract.

For ink contracts, a simple example to reproduce it could be: let foo: String = Decoce::decode(&mut &buf[..]).unwrap().

[ascjones]

Thanks @kvinwang for clarifying and for the repro that is super helpful. It is high priority for this to be resolved ASAP, though it seems we are dependent on that upstream issue being resolved?

Even if we update parity-wasm to support that opcode (it is deprecated...), pallet-contracts itself explicitly disables that feature: https://github.com/paritytech/substrate/blob/master/frame/contracts/src/wasm/mod.rs#LL223C12-L223C12

[webmaster128]

Even if we update parity-wasm to support that opcode (it is deprecated...)

A patch for parity-wasm would be much appreciated ❤️ (I know it's deprecated but still)