internal function pointer

A.sol

// SPDX-License-Identifier: GPL-3.0

// no optimization
pragma solidity 0.8.19;

contract A {
    event Log(string bleh);
    
    // Pass an arbitrary bytecode offset, then make it a fn pointer and call it
    function callme(bytes32 _offset) external {
        function () internal toCall;

        assembly {
            toCall := _offset
        }

        toCall();
    }

    // Avoid having solc removing _irreachable as it is unused
    // + easy way to find the offset
    function dontMindMe() external {
        _irreachable();
    }

    // offset of this: 0x0000000000000000000000000000000000000000000000000000000000000081
    function _irreachable() internal {
        emit Log("pwned pwned pwned");
    }
}