Re: [PATCH] rust: introduce sfile macro for easier code tracing

["Benno Lossin" <lossin@kernel.org>]

On Tue Jun 3, 2025 at 8:15 PM CEST, Timur Tabi wrote:
> On Thu, 2025-05-29 at 22:21 +0200, Miguel Ojeda wrote:
>> If helpers within macros are needed, and especially if the use case is
>> not just temporary debugging statements, then it may be best to put
>> them as helpers outside, to avoid generating all this code on every
>> macro invocation.
>
> That's the beauty of this macro -- it doesn't generate any code.  Not really, at least.  The
> compiler determines at compile time the slice inside file!() that this macro generates, so all that 
> happens is the compiler emits hard-coded offsets into the string literal.
>
> You can see for yourself here:  https://rust.godbolt.org/z/e947zsxfP
>
> This is the whole reason I go through such lengths to avoid rfind() and the .. operator.

It still generates source code that the compiler has to check and
remove. So it'll probably be faster in the long term if we move the
functions outside (and thus only define them once).

---
Cheers,
Benno