How to get a release build with debugging information when using cargo?

As of Rust 1.57, Cargo now allows for custom profiles. This allows you to define your own profile that adds debug information:

[profile.release-with-debug]
inherits = "release"
debug = true

You can then use that profile when building:

% cargo build --profile=release-with-debug
   Compiling buggin v0.1.0 (/tmp/buggin)
    Finished release-with-debug [optimized + debuginfo] target(s) in 0.48s

Prior to this version, or if you always wanted to have debugging information, you can modify the release profile to include debugging symbols:

[profile.release]
debug = true

Note that the release profile and the bench profile differ.

See also

Can tests be built in release mode using Cargo?

How to compile and run an optimized Rust program with overflow checking enabled

Does Cargo support custom profiles?

Or basically any of the top search results for "rust profiling":

Rust Profiling with Instruments and FlameGraph on OSX: CPU/Time

Profiling Rust applications on Linux

Profiling rust code with callgrind

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Another option that I found that does not require changing Cargo.toml is to use the RUSTFLAGS environment variable:

$ RUSTFLAGS=-g cargo build --release

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