rust - How to get assembly output from building with Cargo?

Question

While I've seen docs on using rustc directly to output assembly, having to manually extract commands used by Cargo and edit them to write assembly is tedious.

Is there a way to run Cargo that writes out assembly files?

Answer 1

You can use Cargo's cargo rustc command to send arguments to rustc directly:

cargo rustc -- --emit asm
ls target/debug/deps/<crate_name>-<hash>.s

For optimized assembly:

cargo rustc --release -- --emit asm
ls target/release/deps/<crate_name>-<hash>.s

If you see multiple <crate_name>-<hash>-<hash>.rcgu.s files instead of a <crate_name>-<hash>.s file, disable incremental compilation by setting the environment variable CARGO_INCREMENTAL=0.