SwiftFunction.swift

private struct SwiftFuncWrapper {
    var trampolinePtr: UnsafeMutablePointer<UInt64>
    var functionObject: UnsafeMutablePointer<SwiftFuncObject>
    
    var functionPtr: UnsafeMutableRawPointer {
        let pointer = UnsafeMutablePointer<UInt64>(bitPattern: UInt(functionObject.pointee.address))!
        // Getting actual function ptr from instruction.
        // 0:  55                      push   rbp
        // 1:  48 89 e5                mov    rbp,rsp
        // 4:  5d                      pop    rbp
        // 5:  e9 XX XX ff ff          jmp    0xffffXXXX
        let relativeJmpRel = pointer.pointee >> 48 + (pointer.advanced(by: 1).pointee << 48) >> 32 + 0xffffffff0000000a
        return UnsafeMutableRawPointer(bitPattern: UInt(functionObject.pointee.address &+ relativeJmpRel))!
    }
}

private struct SwiftFuncObject {
    var originalTypePtr: UnsafeMutablePointer<UInt64>
    var unknown: UnsafeMutablePointer<UInt64>
    var address: UInt64
    var selfPtr: UnsafeMutablePointer<UInt64>
}