LKBEN11476: Simple Rust program is huge compared to C or C++


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LKB | Created: 30.12.2020 | Version: 3 | Language: EN | Rating: 0 | Outdated: False | Marked for deletion: False

Author: Wim Peeters - Keskon GmbH & Co. KG

Latest update: 30.12.2020 | Comment:


Symptom

You compiled a simple program with rust and compared the executable with another compiled language

Cause

Rust uses static linking to compile its programs, this makes the exe file bigger

Solution

For this test we use the following "Hello, world" program.
 
fn main() {
    println!("Hello, world!");
}
 
If you comile this program with "cargo build --release" you get 7256712 Bytes or 7 MBytes. (Kubuntu 20.04 with Rustc version 1.43.0)
 
-rwxrwxr-x 2 lubby lubby 7256712 Dez 30 09:55 testrust
 
 
If we take a look at the libraries with ldd, we get:
 
       linux-vdso.so.1 (0x00007ffc83f97000)
       libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fa3b800b000)
       libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fa3b7fe8000)
       libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fa3b7fcd000)
       libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fa3b7ddb000)
       /lib64/ld-linux-x86-64.so.2 (0x00007fa3b8077000)
 
You can tell rust to use dynamic linking by using the following command to compile your code:
 
cargo rustc --release -- -C prefer-dynamic
 
This will produce a much smaller binary of 16992 kBytes in size. (17 kBytes)
 
-rwxrwxr-x 2 lubby lubby 16992 Dez 30 09:46 testrust
 
If we look with ldd we get:
 
       linux-vdso.so.1 (0x00007ffff6393000)
       libstd-b1b61f01951b016b.so => /usr/lib/x86_64-linux-gnu/libstd-b1b61f01951b016b.so (0x00007f9fbeba0000)
       libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9fbe9ae000)
       libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9fbe9a8000)
       libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9fbe985000)
       libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f9fbe96a000)
       /lib64/ld-linux-x86-64.so.2 (0x00007f9fbecea000)
 
Your binary is smaller but you need more libraries. This means you need to provide them when you want to run your software on another system.
 
 

 
 

About the Author

Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.

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