`file_metadata_raw` interns the strings `"<unknown>"` and `""` very
frequently. This commit avoids that, which reduces the number of symbols
interned significantly and reduces instruction counts by up to 0.5% on
some workloads.
In JSON output, emit a directive after metadata is generated.
To implement pipelining, Cargo needs to know when metadata generation is
finished. This is done via a new JSON "directive".
Unfortunately, metadata file writing currently occurs very late during
compilation, so pipelining won't produce a speed-up. Moving metadata
file writing earlier will be a follow-up.
r? @alexcrichton
To implement pipelining, Cargo needs to know when metadata generation is
finished. This commit adds code to do that. Unfortunately, metadata file
writing currently occurs very late during compilation, so pipelining
won't produce a speed-up. Moving metadata file writing earlier will be a
follow-up.
The change involves splitting the existing `Emitter::emit` method in
two: `Emitter::emit_diagnostic` and `Emitter::emit_directive`.
The JSON directives look like this:
```
{"directive":"metadata file written: liba.rmeta"}
```
The functionality is behind the `-Z emit-directives` option, and also
requires `--error-format=json`.
Clarify the short explanation of E0207
After being greatly improved in #33692, https://doc.rust-lang.org/error-index.html#E0207 uses terminology from the related RFC, which is different from the [reference](https://doc.rust-lang.org/reference/items/implementations.html), e.g. "self type" instead of "implementing type" and "trait reference" instead of "implemented trait".
It probably makes no difference to an experienced reader, but for a newbie like me it added to the confusion as you can't look up the definition of the terms being used and can't be sure you've guessed correctly...
I would also move the link to RFC to the top, as it seems to be the only doc that attempts to explain what the third criteria entails), but it seems to go against the accepted style.
Stabilized vectored IO
This renames `std::io::IoVec` to `std::io::IoSlice` and
`std::io::IoVecMut` to `std::io::IoSliceMut`, and stabilizes
`std::io::IoSlice`, `std::io::IoSliceMut`,
`std::io::Read::read_vectored`, and `std::io::Write::write_vectored`.
Closes#58452
r? @alexcrichton
Float 'incomplete_features' out to a const for visibility
Float `let incomplete_features` out to a `const INCOMPLETE_FEATURES` and colocate near `active` features so that it is easier to find and edit.
r? @oli-obk
(use rollup)
rustc: Flag metadata compatible with multiple CGUs
It looks like the `OutputType::Metadata` kind in the compiler was
misclassified in #38571 long ago by accident as incompatible with
codegen units and a single output file. This means that if you emit both
a linkable artifact and metadata it silently turns off multiple codegen
units unintentionally!
This commit corrects the situation to ensure that if `--emit metadata`
is used it doesn't implicitly disable multiple codegen units. This will
ensure we don't accidentally regress compiler performance when striving
to implement pipelined compilation!
Document `Item` type in `std::env::SplitPaths` iterator.
Previously there wasn't any documentation to show what the type of
`Item` was inside `std::env::SplitPaths`. Now, in the same format as
other examples of docs in `std` for `Iterator#Item`, we mention the
type.
This fixes#59543.
r? @steveklabnik
