How to get assembly output from building with Cargo?

assembly rust rust-cargo
ideasman42 picture ideasman42 · Aug 30, 2016 · Viewed 15.7k times · Source

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

kennytm picture kennytm · Aug 30, 2016

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.

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