This is a long but really great blog post: https://darkcoding.net/software/a-very-small-rust-binary-indeed/
Try compiling a really basic Rust program on Ubuntu:
fn main() {
println!("Hello");
}
rustc -C opt-level=z -C lto -C strip=symbols prog.rs
The binary is about 300 kB. This will shring down to about 16 kB (the same size as a minimal C or C++ program compiled on Linux) is you add an addition
-C prefer-dynamic
But this won't run on Linux (unlike the C and C++ binaries) because it cannot find the libraries:
./prog: error while loading shared libraries: libstd-d5189b81a4fa4d36.so: cannot open shared object file: No such file or directory
- https://github.com/johnthagen/min-sized-rust
- https://stackoverflow.com/questions/29008127/why-are-rust-executables-so-huge
Rust binaries even for "Hello, world!" can be large. Quoting:
Rust uses static linking to compile its programs, meaning that all libraries required by even the simplest Hello world! program will be compiled into your executable. This also includes the Rust runtime.
I created a Linux executable Rust release using the following in cargo.toml:
[profile.release]
opt-level = 'z' # Optimize for size
codegen-units = 1 # Reduce number of codegen units to increase optimizations
panic = 'abort' # Abort on panic
strip = true # Strip symbols from binary*
The resultant binary was 342 kB.
UPX (https://github.com/upx/upx) is recommended to compress the final binary by 50-70%. UPX releases on Github are themselves about 670 kB and cross platform (Win + Linux, no Mac it seems).
I downloaded the Linux version "upx-4.2.4-amd64_linux.tar.xz" (UPX - Linux version, statically linked) and dragged the single binary file "upx" into the root folder of my Rust project. I then used UPX to compress the 342 kB binary down to 139 kB as follows:
./upx --best --lzma target/release/my_release_binary
Cargo has no post precessing capability, so... create a bash script: touch compile_compress_run.sh and make executable chmod +x compile_compress_run.sh. Add the following to the script:
#!/bin/bash
cargo build --release
./upx --best --lzma target/release/my_release_binary
target/release/my_release_binary
To run the script use ./compile_compress_run.sh.
- https://github.com/watchexec/cargo-watch
- https://stackoverflow.com/questions/29461693/how-can-i-get-cargo-to-recompile-changed-files-automatically
Execute the following in VSCode Terminal to automatically recompile and run upon save:
cargo watch -q -c -w src -x run
For --release code, use the following:
cargo watch -q -c -w src -x 'run -- --release'