[FEATURE] Use smart contract-based binary search to find userop gas limits

[0xSulpiride]

Is your feature request related to a problem? Please describe.
Skandha started to misestimate gas limits of userops that use EntryPoint v0.7.0.
We need to switch to smart-contract based binary search algorithm for better estimation of gas limits.

Describe the solution you'd like
We should implement the same approach that Rundler does.
They use this contract: https://github.com/alchemyplatform/rundler/blob/307e8c2cbeab80518a56a2f309e994de3b1631f0/crates/types/contracts/src/v0_7/CallGasEstimationProxy.sol

[nikhilkumar1612]

I'm taking a look into this.

[ch4r10t33r]

Thank you @nikhilkumar1612

Do give us a shout if you have any questions.

[nikhilkumar1612]

hey i have a few questions:

1. If a eth_call is made to entrypoint contract's address after overriding its state to CallGasEstimateProxy's bytecode, how will the call even reach simulateHandleOps ? because both contracts are not meant for deployment. I understand that this proxy based approach is done to satisfy the require(address(this) == msg.sender) inside estimateCallGas() but since the deployed instance of an entrypoint will not have both the functionalities how will this work ?
2. IMPLEMENTATION_ADDRESS_MARKER - constant in CallGasEstimationProxyTypes is this address entrypoint ?
3. what exactly does this line mean - L32.

[0xSulpiride]

Hi @nikhilkumar1612 thanks for picking up this issue!

1. CallGasEstimationProxy is a proxy that delegates all calls to the _implementation() contract (if no function from it's body matches the selector). So we need 2 overrides in eth_call. One that overrides EntryPoint's address to CallGasEstimationProxy's code and another to override PROXY_IMPLEMENTATION_ADDRESS_MARKER to EntryPoint's code. This way when we call simulateHandleOps on CallGasEstimationProxy, proxy will delegatecall it to EntryPoint
2. It's just a random address
3. Explained in 1.

Let me know if you have more questions!

[nikhilkumar1612]

thanks @0xSulpiride . I have completed the changes needed for the types,
are these changes relavant to v6 as well ? or is this enhancement only relavant to v7 ?

[0xSulpiride]

@nikhilkumar1612 this is only relevant to v7

[ch4r10t33r]

thanks @0xSulpiride . I have completed the changes needed for the types, are these changes relavant to v6 as well ? or is this enhancement only relavant to v7 ?

Thank you @nikhilkumar1612 Please create a PR when ready.

[nikhilkumar1612]

hi guys please find my PR and let me know the changes.
@0xSulpiride @ch4r10t33r