rust/src/librustc/benches/lib.rs

#![feature(slice_patterns)]
#![feature(test)]

extern crate test;

use test::Bencher;

// Static/dynamic method dispatch

struct Struct {
    field: isize
}

trait Trait {
    fn method(&self) -> isize;
}

impl Trait for Struct {
    fn method(&self) -> isize {
        self.field
    }
}

#[bench]
fn trait_vtable_method_call(b: &mut Bencher) {
    let s = Struct { field: 10 };
    let t = &s as &dyn Trait;
    b.iter(|| {
        t.method()
    });
}

#[bench]
fn trait_static_method_call(b: &mut Bencher) {
    let s = Struct { field: 10 };
    b.iter(|| {
        s.method()
    });
}

// Overhead of various match forms

#[bench]
fn option_some(b: &mut Bencher) {
    let x = Some(10);
    b.iter(|| {
        match x {
            Some(y) => y,
            None => 11
        }
    });
}

#[bench]
fn vec_pattern(b: &mut Bencher) {
    let x = [1,2,3,4,5,6];
    b.iter(|| {
        match x {
            [1,2,3,..] => 10,
            _ => 11,
        }
    });
}