feat(arbiter-core): EVM stack tracing

[0xJepsen]

No description provided.

[Autoparallel]

Can you expand on this please?

[0xJepsen]

Yeah there are i guess two types of stack traces that could be nice for debugging calls when a call fails.

• One in solidity: Saw we have a call to the dfmm contracts fail. For example consider that the entry point was called from the atomic arb contract. Meaning we aren't sure which frame the call fails in. Is there a way to to deliver the user the solidity stack trace looking something like

Error: Transaction reverted: {Revert Reason}
  at MyContract.someFunction (contracts/MyContract.sol:25)
  at MyContract.anotherFunction (contracts/MyContract.sol:50)
  at some_eoa_call (test/MyContractWrapper.rs:30) (would it be possible to log the eoa file? would be sick)

• The other type of stack trace that could be useful would be the opcode stack trace which is much more low lever but for a function like

function add(uint x, uint y) public pure returns (uint) {
    return x + y;
}

could look like this (not confident this matches the above function perfectly but gets the point across)

1. PUSH1 0x20        // Push 32 bytes (size of one uint256) to the stack
2. PUSH1 0x04        // Push 4 bytes (offset for the first argument) to the stack
3. CALLDATALOAD      // Load first argument (x) from call data
4. PUSH1 0x24        // Push 36 bytes (offset for the second argument) to the stack
5. CALLDATALOAD      // Load second argument (y) from call data
6. ADD               // Add x and y
7. PUSH1 0x00        // Push 0 (offset for return data) to the stack
8. MSTORE            // Store the result at memory location 0
9. PUSH1 0x20        // Push 32 bytes (size of return data) to the stack
10. PUSH1 0x00       // Push 0 (offset for return data) to the stack
11. RETURN           // Return the result

[Autoparallel]

How would you want to go about implementing this in arbiter?

[0xJepsen]

I was thinking at a high level that an inspector might work for the opcode level stack trace.
But for solidity stack traces i don't know thats needs some more thought