src/librustc/benches/dispatch.rs


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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

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 &Trait;
    b.iter(|| {
        t.method()
    });
}

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