Bootstrapping into useful testing phase

[axic]

It would be fairly simple to move this from an isolated test into a more useful testing framework by adjusting one of the VM implementations.

The adjustment would include to run the eWASM VM when a contract bytecode starts with the WASM bytecode signature (\0asm).

This can be easily achieved by using ethereumjs-vm, which then would provide a state and full blockchain.

Depending on ABI decision (#1), wrapper methods for callCode and delegateCall might be needed to transform between the new and current ABIs.

[wanderer]

I think this would be good for a test network. I'm not sure if it will suffice for the whole network yet though. One concern with putting something like this on the live network would be twice the surface area for consensus breaking bugs

[axic]

Also prefixing the bytecode with an EVM1 code piece (e.g. RETURN, STOP to stop execution) could make this compatible with the current network. An EVM1 contract deployment code would be needed also.

It doesn't need to go onto Frontier/Homestead, but at least would be easy to work with it on a private testnet.

Note: STOP itself has bytecode of 0x00. The WASM bytecode starts with the same and thus no prefix is needed.

[axic]

As a note, WASM prototype-1 had a magic string of wasm, while prototype-2 has \0asm.

[axic]

This backwards compatible part is now incorporated into #42.

There's a VM in progress with the above considered: https://github.com/ewasm/ewasm-kernel