Why does the Rust compiler generate huge executables?

Question

Compiling a simple hello world application like this:

fn main() {
    println!("Hello, World!");
}

Generates a relatively huge 822 KB executable using the default compiler options (rustc hello.rs).

Why does this happen and what is the best way to reduce the size of the executable?

AFAIK, much or all of the standard library is linked into the binary statically by default. Try optimization -O and/or strip. For kicks and giggles you may also link to libstd etc dynamically (not sure how, though). — sellibitze
-Z lto (link-time optimisations) shrinks things plenty too. — Chris Morgan

PEPP PEPP · Accepted Answer · 2014-12-06T10:34:27

The standard library is linked statically by default. You can change that by passing the -C prefer-dynamic option to the compiler.
Rust is still a very young language with an incompletely optimized compiler. There is still a lot of room left for improvements in compilation speed, code speed and size, wording of error messages and so on.