profile - The Rust Unstable Book

# `profile`

The tracking issue for this feature is: #42524.

This feature allows the generation of code coverage reports.

Set the `-Zprofile` compiler flag in order to enable gcov profiling.

For example:

    cargo new testgcov --bin
    cd testgcov
    export RUSTFLAGS="-Zprofile"
    cargo build
    cargo run

Once you've built and run your program, files with the `gcno` (after build) and `gcda` (after execution) extensions will be created. You can parse them with llvm-cov gcov or grcov.