Perhaps then the OS should figure out which parts of an executable are common, so we can still have shared libraries except they are smarter and not visible to the user.
Except "being visible to the user" is a useful thing to have, as GP explained :).
Or put in a different way: the problem is the "shared" part, not the "dynamic linking" part. Instead of static linking, you can avoid the issue of library versions by just shipping your shared libraries along with your program[0] - and this way, users still retain the ability to swap out components if the need arises.
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[0] - Well, you could, if you could rely on LD_LIBRARY_PATH to be set to "." by default. Windows is doing it right, IMO, by prioritizing program location over system folders when searching for DLLs to load.
Thanks! I forgot all about it, in particular about '$ORIGIN' thing! Yes, I'm happy to see the person building the executable has at least some control over this.
It's actually relevant to a project I'm working on (proprietary, Windows/Linux, uses shared libraries for both mandatory components and optional plugins) - I'm gonna check if and how we're setting RPATH for the Linux builds, it might need some tweaking.
It's definitely technically doable: you'd have to checksum every read-only page of a program and see if you already have one in cache.
But is it worth it though? Even "big" statically linked Rust programs are a few dozen MBs of executable (and not all of that is read-only, and even less will be shared with any other executable at any given time). With things like LTO identical source files can result in different machine code as well.
In the end it would be a lot of trouble for potentially very little gains.
At first I was annoyed that Rust defaulted to dynamic linking, it felt inefficient and overkill. But the more I think about it the less I can really justify doing it any other way, there are very few benefits to dynamic linking these days. The only one I can think of is overriding an application's behaviour through LD_PRELOAD, but few people know how to do that these days.
