Why Kotlin native generated executable is larger than the equivalent in rust


#1

Considering both Kotlin-native and Rust are based on LLVM, I expect there output and performance to be close!

So created 2 simple Hello World! with kotlin and rust

main.kt:

fun main() {
    println("Hello, world!")
}

main.rs:

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

Then generated the executable files for bot using:
kotlinc-native main.kt for kotlin and cargo build for rust

Then checked the executables/binary using the below:

ls -S -lh | awk '{print $5, $9}'

and found that the file generated by kotlin native is 1.48X the file generated by rust.

Any idea why this variance!

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Moreover Rust can be optimized to be smaller, Is there something simliar in Kotlin native?

Initial setup:

$ cargo new hello_world

Build with:
$ cargo build

:point_right:t2: 589,004 bytes

Optimization Step 1:

Build with:
$ cargo build --release

:point_right:t2: 586,028 bytes

Optimization Step 2:

Change contents of main.rs to:

use std::alloc::System;

#[global_allocator]
static A: System = System;

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

:point_right:t2: 335,232 bytes

Optimization Step 3:

Add …

[profile.release]
lto = true

to Cargo.toml .

:point_right:t2: 253,752 bytes

Optimization Step 4:

Strip executable via …
$ strip target/release/hello_world

:point_right:t2: 177,608 bytes

So, we ended up having the file generated by kotlin native is 4.87X (~ 5X) the file generated by rust


#2

I guess the stdlib of Kotlin is just bigger.


#3

Garbage collector?


#4

Reference counting in case of K/N.
Considering that Rust have almost no runtime and kotlin does, the difference of about 300k seems very small.