Optimize str::repeat
Improves the performance of `str::repeat` by bulk copying. Here is the benchmarks of `"abcde".repeat(n)`:
|`n`|old [ns/iter]|new [ns/iter]|diff [%]|
---|---|---|---
|1|27.205|27.421|+0.794|
|2|27.500|27.516|+0.0581|
|3|27.923|27.648|-0.985|
|4|31.206|30.145|-3.40|
|5|35.144|31.861|-9.34|
|7|43.131|34.621|-19.7|
|10|54.945|36.203|-34.1|
|100|428.31|52.895|-87.7|
Don't recompute SymbolExportLevel for upstream crates.
The data collected in #48373 suggests that we can avoid generating up to 30% of the LLVM definitions by only instantiating function monomorphizations once with a given crate graph. Some more data, collected with a [proof-of-concept implementation](https://github.com/michaelwoerister/rust/commits/share-generics) of re-using monomorphizations, which is less efficient than the MIR-only RLIB approach, suggests that it's still around 25% LLVM definitions that we can save.
So far, this PR only cleans up handling of symbol export status. Too early to review still.
Add functions for reversing the bit pattern in an integer
I'm reviving PR #32798 now that the LLVM issues have been resolved.
> This adds the bitreverse intrinsic and adds a reverse_bits function to all integer types.
Suggest type for overflowing bin/hex-literals
Fixes#48073
For hexadecimal and binary literals, which overflow, it gives an additional note to the warning message, like in this [comment](https://github.com/rust-lang/rust/issues/48073#issuecomment-365370113).
Additionally it will suggest a type (`X < Y`):
- `iX`: if literal fits in `uX` => `uX`, else => `iY`
- `-iX` => `iY`
- `uX` => `uY`
Exceptions: `isize`, `usize`. I don't think you can make a good suggestion here. The programmer has to figure it out on it's own in this case.
r? @oli-obk
Slight modification to the as_ref example of std::option::Option
A user in a reddit thread was confused by the name of the variable
"num_as_int"; they thought the example was trying to convert the
string "10" as if it were binary 2 by calling str::len(). In reality,
the example is simply demonstrating how to take an immutable reference
to the value of an Option. The confusion comes from the coincidence
that the length of the string "10" is also its binary representation,
and the implication from the variable names that a conversion was
occuring ("num_as_str" to "num_as_int").
This PR changes the example number to 12 instead of 10, and changes
the variable name from "num_as_int" to "num_length" to better
communicate what the example is doing.
The reddit thread:
https://www.reddit.com/r/rust/comments/7zpvev/notyetawesome_rust_what_use_cases_would_you_like/dur39xw/
This Python script converts documentation comments from the
`#[doc = "..."]` attribute to the `///` syntax. It was added six
years ago, presumably to help with the transition when `///` was
implemented and hasn't really been touched since. I don't think there's
much value in keeping it around at this point.
Turn feature-gate table into a query so it is covered by dependency tracking.
Turn access to feature gates into a query so we handle them correctly during incremental compilation.
Features are still available via `Session` through `features_untracked()`. I wish we had a better way of hiding untracked information. It would be great if we could remove the `sess` field from `TyCtxt`.
Fixes#47003.
