Is there a documentation on how to run a simple example with wasmi?

[djolertrk]

Hello,

I am wondering, is there a documentation on how to interpret a simple .wasm file, for example the https://github.com/paritytech/ink#hello-world--the-flipper with this tool? :)
IIUIC, the idea of the interpreter, among the other goals, is to be able to interpret .wasm files "offline", right?

Thanks in advance!

[Robbepop]

The wasmi interpreter repository provides a wasmi_cli application out of the box that allows to run raw Wasm files and soon WASI compatible Wasm files with the following command when your work directory is in the wasmi repository:

cargo run --package wasmi_cli <WASM_FILE> <FUNCTION_NAME> [<FUNC_ARGS>]*

Where WASM_FILE is the Wasm file path, FUNCTION_NAME is the name of the exported function of the Wasm file you want to call and [<FUNC_ARGS>]* is the optional number of arguments for the called function.

However, in your special case this tool won't help you since you apparently want to run ink! smart contracts using wasmi. However, ink! smart contracts require a special environment that is defined by the contracts-pallet. WebAssembly only defines an abstract virtual machine but what you want is a concrete invokation of a specific one - namely the Substrate contracts Wasm VM.

Therefore your best bet is to use the ink! playground to toy around a bit or alternative use a proper Substrate smart contracts UI to make use of a deployed chain.

[djolertrk]

Ahh, OK. Thanks a lot anyway! I thought I could do it without a chain.

Basically, I am interested in seeing what would be the scenario with the program if it crashes (for example read from a 0x0 mem address) - more precisely, I am wondering if there is a "coredump" like file that is being generated by the WASM VM.

[Robbepop]

Actually, there are some ink! smart contract instantiation benchmarks for wasmi that might give you an idea of what is needed to make them run. However, I guess that they are not that useful without context: https://github.com/paritytech/wasmi/blob/master/crates/wasmi/benches/benches.rs#L134