How is the execution of generic functions performed during program compilation?

Generic functions are processed at compile time using a mechanism called "monomorphization" or template instantiation. This means that the compiler creates specific versions of the function for each type it is used with.

For example, if you have a generic function:

func swapValues<T>(_ a: inout T, _ b: inout T) {
    let temp = a
    a = b
    b = temp
}

and you call it with Int and String, the compiler will generate two versions of the function: one for Int, and another for String. This helps avoid runtime overhead associated with dynamic typing.

In some languages (like Java), generics are implemented via type erasure, whereas in Swift, they are implemented through monomorphization.