Rename std::ptr::Shared to NonNull and stabilize it
This implements the changes proposed at https://github.com/rust-lang/rust/issues/27730#issuecomment-352800629:
> * Rename `Shared<T>` to `NonNull<T>` and stabilize it. (Being in the `ptr` module is enough to say that it’s a pointer. I’m not very attached to this specific name though.)
> * Rename `Box<T>` methods ~~`from_unique`~~/`into_unique` to ~~`from_nonnull`~~/`into_nonnull` (or whatever names are deemed appropriate), replace `Unique<T>` with `NonNull<T>` in their signatures, and stabilize them.
> * Replace `Unique<T>` with `NonNull<T>` in the signatures of methods of the `Alloc` trait.
> * Mark `Unique` “permanently-unstable” by replacing remaining occurrences of `#[unstable(feature = "unique", issue = "27730")]` with:
>
> ```rust
> #[unstable(feature = "ptr_internals", issue = "0", reason = "\
> use NonNull instead and consider PhantomData<T> (if you also use #[may_dangle]), \
> Send, and/or Sync")]
> ```
>
> (Maybe the `reason` string is only useful on the struct definition.) Ideally it would be made private to some crate instead, but it needs to be used in both liballoc and libstd.
> * (Leave `NonZero` and `Zeroable` unstable for now, and subject to future bikeshedding.)
Thew `_raw` prefix is included because the fact that `Box`’s ownership
semantics are "dissolved" or recreated seem more important than the exact
parameter type or return type.
- use consistent phrasing for expected and found arguments
- suggest changing arugments to tuple if possible
- suggest changing single tuple argument to arguments if possible
LLVM <= 4.0 used a non-standard interpretation of `DW_OP_plus`. In the
DWARF standard, this adds two items on the expressions stack. LLVM's
behavior was more like DWARF's `DW_OP_plus_uconst` -- adding a constant
that follows the op. The patch series starting with [D33892] switched
to the standard DWARF interpretation, so we need to follow.
[D33892]: https://reviews.llvm.org/D33892
Speed up leb128 encoding and decoding for unsigned values.
Make the implementation for some leb128 functions potentially faster.
@Mark-Simulacrum, could you please trigger a perf.rlo run?
This is a forward-port of:
* 9426dda83d
* cbfb985895
from the beta branch which is used to automatically calculate the beta number
based on the number of merges to the beta branch so far.
avoid double-unsizing arrays in bytestring match lowering
The match lowering code, when lowering matches against bytestrings,
works by coercing both the scrutinee and the pattern to `&[u8]` and
then comparing them using `<[u8] as Eq>::eq`.
If the scrutinee is already of type `&[u8]`, then unsizing it is both
unneccessary and a trait error caught by the new and updated MIR typeck,
so this PR changes lowering to avoid doing that (match lowering tried to
avoid that before, but that attempt was quite broken).
Fixes#46920.
r? @eddyb
Though some parts of rust use cc-rs to invoke a compiler/linker, Cargo
seems to make use of the TargetOptions::linker property. Make the out of
the box experience for CloudABI a bit better by using the same compiler
name as cc-rs.
