feat(revm): allow for Evm to be Send + Sync

[Autoparallel]

Problem

Right now, we cannot share Evm<_> across thread boundaries as there are certain handlers that are not set to be Send + Sync. E.g.:

revm/crates/revm/src/handler/handle_types/validation.rs

Lines 9 to 19 in 13ce013

	pub type ValidateEnvHandle<'a, DB> =
	Arc<dyn Fn(&Env) -> Result<(), EVMError<<DB as Database>::Error>> + 'a>;
	/// Handle that validates transaction environment against the state.
	/// Second parametar is initial gas.
	pub type ValidateTxEnvAgainstState<'a, EXT, DB> =
	Arc<dyn Fn(&mut Context<EXT, DB>) -> Result<(), EVMError<<DB as Database>::Error>> + 'a>;
	/// Initial gas calculation handle
	pub type ValidateInitialTxGasHandle<'a, DB> =
	Arc<dyn Fn(&Env) -> Result<u64, EVMError<<DB as Database>::Error>> + 'a>;

This restricts being able to do Arc<RwLock<Evm<_>>> and having shared access to an Evm<_> instance where one could be able to parallelize over read-only txs.

Solution

• I have brought this up before, but we could simply tag those dyn Fns with Send + Sync, however I don't think this is what revm wants. Perhaps this could be an option under a feature flag?
• There could be other ways around this. Do we have any ideas on what would be acceptable?

Related Issues

It was brought up that #916 was related, and I began trying to work on this. I want to open up this issue here to keep it in mind and discuss.

[rakita]

This is probably not going to happen with whole Evm what i would recommend is to use and send Context while rebuilding Handler when needed.

[CorrM]

This is probably not going to happen with whole Evm what i would recommend is to use and send Context while rebuilding Handler when needed.

The database will still be a problem to be shared.
Clone the context will make a snapshot of the DB then it's not a true shared state. (correct me if I'm wrong)