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The compiler currently has `-Ztime` and `-Ztime-passes`. I've used `-Ztime-passes` for years but only recently learned about `-Ztime`. What's the difference? Let's look at the `-Zhelp` output: ``` -Z time=val -- measure time of rustc processes (default: no) -Z time-passes=val -- measure time of each rustc pass (default: no) ``` The `-Ztime-passes` description is clear, but the `-Ztime` one is less so. Sounds like it measures the time for the entire process? No. The real difference is that `-Ztime-passes` prints out info about passes, and `-Ztime` does the same, but only for a subset of those passes. More specifically, there is a distinction in the profiling code between a "verbose generic activity" and an "extra verbose generic activity". `-Ztime-passes` prints both kinds, while `-Ztime` only prints the first one. (It took me a close reading of the source code to determine this difference.) In practice this distinction has low value. Perhaps in the past the "extra verbose" output was more voluminous, but now that we only print stats for a pass if it exceeds 5ms or alters the RSS, `-Ztime-passes` is less spammy. Also, a lot of the "extra verbose" cases are for individual lint passes, and you need to also use `-Zno-interleave-lints` to see those anyway. Therefore, this commit removes `-Ztime` and the associated machinery. One thing to note is that the existing "extra verbose" activities all have an extra string argument, so the commit adds the ability to accept an extra argument to the "verbose" activities. |
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| Cargo.toml | ||
| README.md | ||
The driver crate is effectively the "main" function for the rust
compiler. It orchestrates the compilation process and "knits together"
the code from the other crates within rustc. This crate itself does
not contain any of the "main logic" of the compiler (though it does
have some code related to pretty printing or other minor compiler
options).
For more information about how the driver works, see the rustc dev guide.