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.<

Answer 1

In addition to kennytm's answer, you can also use the RUSTFLAGS environment variable and use the standard cargo commands:

RUSTFLAGS="--emit asm" cargo build
cat target/debug/deps/project_name-hash.s

Or in release mode (with optimizations):

RUSTFLAGS="--emit asm" cargo build --release
cat target/release/deps/project_name-hash.s

You can pass different values to the --emit parameter, including (but not limited to):

• mir (Rust intermediate representation)
• llvm-ir (LLVM intermediate representation)
• llvm-bc (LLVM byte code)
• asm (assembly)