Comment by jneem
I had a quick look and couldn't find a way to turn off per-function sections in rustc. But I think it's a pretty good default for rust, because the unit of compilation is pretty large and so it's common to have a lot of unused functions. It's really only a problem for distributing static libraries, since binaries and shared libraries already lose their per-function sections.
I would rather say it's really only potentially beneficial for distributing static libraries, since binaries and shared libraries already lose their per-function sections. So they pay the cost of the fluffier code without getting much benefit, if any.