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Nicholas Nethercote
08683f003c
The current situation is something of a mess. - `IdxSetBuf` derefs to `IdxSet`. - `IdxSetBuf` implements `Clone`, and therefore has a provided `clone_from` method, which does allocation and so is expensive. - `IdxSet` has a `clone_from` method that is non-allocating and therefore cheap, but this method is not from the `Clone` trait. As a result, if you have an `IdxSetBuf` called `b`, if you call `b.clone_from(b2)` you'll get the expensive `IdxSetBuf` method, but if you call `(*b).clone_from(b2)` you'll get the cheap `IdxSetBuf` method. `liveness_of_locals()` does the former, presumably unintentionally, and therefore does lots of unnecessary allocations. Having a `clone_from` method that isn't from the `Clone` trait is a bad idea in general, so this patch renames it as `overwrite`. This avoids the unnecessary allocations in `liveness_of_locals()`, speeding up most NLL benchmarks, the best by 1.5%. It also means that calls of the form `(*b).clone_from(b2)` can be rewritten as `b.overwrite(b2)`.
This directory contains the source code of the rust project, including:
rustcand its testslibstd- Various submodules for tools, like rustdoc, rls, etc.
For more information on how various parts of the compiler work, see the rustc guide.
Their is also useful content in the following READMEs, which are gradually being moved over to the guide:
- https://github.com/rust-lang/rust/tree/master/src/librustc/ty/query
- https://github.com/rust-lang/rust/tree/master/src/librustc/dep_graph
- https://github.com/rust-lang/rust/blob/master/src/librustc/infer/region_constraints
- https://github.com/rust-lang/rust/tree/master/src/librustc/infer/higher_ranked
- https://github.com/rust-lang/rust/tree/master/src/librustc/infer/lexical_region_resolve