core/vm: add switches to select evm+ewasm interpreters

[gballet]

Interpreter initialization is left to the PRs implementing them.

There is a commented-out part that needs to be uncommented in order to initialize the proper interpreter when need be; for instance, in the case of ewasm and assuming that --ewasm.interpreter is evmc:path then the code should be something like:

params := strings.Split(, ":")
switch params[0] {
case "evmc":
  if len(params) != 2 {
  panic("Missing vm path in evmc:path argument to ewasm.interpreter")
  }
  vmPath := params[1]
  evm.interpreters = append(evm.interpreters, NewEVMC(evm, vmPath))
  break;
  ...
}

and the panic should be removed.

[chfast]

Is there a way to run tests with an external EVMC VM? E.g. --evm.interpreter evmc:aleth-interpreter.so? Can go test ./tests/... accept custom flags?

[chfast]

EVMC supports also custom options. Can will add additional flag, e.g. --evmc.options option1=x;option2=y?

[karalabe]

This should be defined by a hard fork rule, not a CLI flag.

[karalabe]

Please name these --vm.evm and --vm.ewasm. The defaults should be empty, which geth can interpret by running the built in VMs.

[karalabe]

Also add (default = built in implementation)

[karalabe]

Whether ewasm is enabled or not is not a configuration value, it's a chain fork rule.

[karalabe]

Please get rid of geth and wagon. Empty means built in, non empty means use something else.

[karalabe]

Please use nil. big.NewInt(0) enables EWASM at block 0.

[karalabe]

Please use nil. big.NewInt(0) enables EWASM at block 0.

[karalabe]

Please use nil. big.NewInt(0) enables EWASM at block 0.

[karalabe]

Please move this up after the rest of the fork definitions.

[karalabe]

"Constantinople" -> "EWASM"

[gballet]

Is there a way to run tests with an external EVMC VM? E.g. --evm.interpreter evmc:aleth-interpreter.so? Can go test ./tests/... accept custom flags?

you can write those tests

EVMC supports also custom options. Can will add additional flag, e.g. --evmc.options option1=x;option2=y?

I would say that's part of the EVMC pr: if you have --vm.evm=path:option1:option2 that should work .

[ghost]

Can't wait to implement eWASM on mainnet 😂

[karalabe]

Please remove "wagon" and "geth"

[karalabe]

ping

[karalabe]

Lets keep the comment consistent with the other ones.

// EWASM switch block (nil = no fork, 0 = already activated)

[karalabe]

External EWASM configuration (default = built in interpreter)

[karalabe]

External EVM configuration (default = built in interpreter)

[axic]

Does this needs to be colon separated or can anything be passed after evmc:path:.... ?

[gballet]

anything can be passed

[karalabe]

You can use the same comments as for the flag.

External eWASM configuration and External EVM configuration

I wouldn't mention the config string here yet, since it's not even implemented, so we don't know what it will be. We do know it won't be the one you listed though (no evmc).

[axic]

Can you use ewasm instead of eWASM as that is the current naming style?

[gballet]

@axic is this the current or the definitive naming style? 😄

[axic]

Current, could change.

But there is agreement eWASM is not the way to go :)

[karalabe]

LGTM

[chfast]

Sorry, but you missed 64 other places where vm.Config{} is created. I'm not even sure if the new incoming transactions are going to be executed with the selected VM.

[gballet]

@chfast those other location correspond to tests and simulations and we want to use the native interpreter in them. Incoming transactions will be executed by the VM, if you don't believe us check it for yourself.

[chfast]

I believe you. I just remember I had to change this in two places. Maybe it was about tests.