[TIMING] debug output does not distinguish checking from building

[jyn514]

While debugging the CI failure in #95450, I saw the following output in the logs:

2022-04-13T11:24:41.1948979Z [TIMING] Rustc { stage: 2, target: TargetSelection { triple: "x86_64-unknown-linux-gnu", file: None } } -- 113.867
2022-04-13T11:25:13.1594039Z [TIMING] Rustc { target: TargetSelection { triple: "x86_64-unknown-linux-gnu", file: None } } -- 31.963

The first one is doc::Rustc and the second I think is check::Rustc, by the fields it has. But we should just print that in the debug logs rather than having to guess.

@rustbot label +A-contributor-roadblock +C-enhancement

[jyn514]

This will be annoying to fix because we'll have to remove derive(Debug) for Step and implement it by hand. Maybe we could introduce a new macro making it easier? The module name is available through https://doc.rust-lang.org/stable/std/macro.module_path.html

[jyn514]

@rustbot label +E-medium +E-mentor +A-rustbuild

[Mark-Simulacrum]

The way to go is likely to add type_name to the timing print rather than solely relying on Debug.