Based on rust-lang#68692

- Defer to Ipv4Addr::fmt when printing an Ipv4 address
- Fast path: write directly to f without an intermediary buffer when
  there are no alignment options
- Simplify finding the inner zeroes-span

Enables Range<char> to be iterable

Note: https://rust.godbolt.org/z/fdveKo
An iteration over all char ('\0'..=char::MAX)
includes unreachable panic code currently.
Updating RangeInclusive::next to call
Step::forward_unchecked (which is safe to do
but not done yet becuase it wasn't necessary)
successfully removes the panic from this iteration.

Co-authored-by: Amanieu d'Antras <amanieu@gmail.com>

Miri's pointer_offset_inbounds implementation has been moved into
librustc_mir as ptr_offset_inbounds (to avoid breaking miri on a
nightly update). The comments have been slightly reworked to better
match `offset`'s external documentation about what causes UB.

The intrinsic implementations are taken directly from miri.

Signed-off-by: Joe Richey <joerichey@google.com>

Signed-off-by: Joe Richey <joerichey@google.com>

Signed-off-by: Joe Richey <joerichey@google.com>

Signed-off-by: Joe Richey <joerichey@google.com>

Signed-off-by: Joe Richey <joerichey@google.com>

This is tricky to get right if we want to avoid panicking or wrapping.

Signed-off-by: Joe Richey <joerichey@google.com>

The previous code paniced if offset_bytes == i64::MIN. This commit:
  - Properly computes the absoulte value to avoid this panic
  - Adds a test for this edge case

Signed-off-by: Joe Richey <joerichey@google.com>

…or packed borrows in unsafe fns

Detect type parameter that might require lifetime constraint.
Do not name `ReVar`s in expected/found output.
Reword text suggesting to check the lifetimes.

We now perform the correct checks even if the pointer size differs
between the host and target.

Signed-off-by: Joe Richey <joerichey@google.com>

Tweak impl signature mismatch errors involving `RegionKind::ReVar` lifetimes

Fix rust-lang#66406, fix rust-lang#72106.

```
error: `impl` item signature doesn't match `trait` item signature
  --> $DIR/trait-param-without-lifetime-constraint.rs:14:5
   |
LL |     fn get_relation(&self) -> To;
   |     ----------------------------- expected `fn(&Article) -> &ProofReader`
...
LL |     fn get_relation(&self) -> &ProofReader {
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&Article) -> &ProofReader`
   |
   = note: expected `fn(&Article) -> &ProofReader`
              found `fn(&Article) -> &ProofReader`
help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait`
  --> $DIR/trait-param-without-lifetime-constraint.rs:10:31
   |
LL |     fn get_relation(&self) -> To;
   |                               ^^ consider borrowing this type parameter in the trait
```

r? @nikomatsakis

impl From<[T; N]> for Box<[T]>

Based on rust-lang#68692

Make pointer offset methods/intrinsics const

Implements rust-lang#71499 using [the implementations from miri](https://github.com/rust-lang/miri/blob/52f5d202bdcfe8986f0615845f8d1647ab8a2c6a/src/shims/intrinsics.rs#L96-L112).

I added some tests what's allowed and what's UB. Let me know if any other cases should be added.

CC: @RalfJung @oli-obk

linker: Support `-static-pie` and `-static -shared`

This PR adds support for passing linker arguments for creating statically linked position-independent executables and "statically linked" shared libraries.

Therefore it incorporates the majority of rust-lang#70740 except for the linker rerun hack and actually flipping the "`static-pie` is supported" switch for musl targets.

…afe-fn, r=nikomatsakis

Implement RFC 2585: unsafe blocks in unsafe fn

Tracking issue: rust-lang#71668
r? @RalfJung cc @nikomatsakis

…chievink

borrowck `DefId` -> `LocalDefId`

Replaces some `DefId`s which must always be local with `LocalDefId` in `librustc_mir/borrowck`.

cc @marmeladema

…lacrum

Various minor improvements to Ipv6Addr::Display

Cleaned up `Ipv6Addr::Display`, especially with an eye towards simplifying and reducing duplicated logic. Also added a fast-path optimization, similar to rust-lang#72399 and rust-lang#72398.

- Defer to `Ipv4Addr::fmt` when printing an Ipv4 address
- Fast path: write directly to `f` without an intermediary buffer when there are no alignment options
- Simplify finding the inner zeroes-span

impl Step for char (make Range*<char> iterable)

[[irlo thread]](https://internals.rust-lang.org/t/mini-rfc-make-range-char-work/12392?u=cad97) [[godbolt asm example]](https://rust.godbolt.org/z/fdveKo)

Add an implementation of the `Step` trait for `char`, which has the effect of making `RangeInclusive<char>` (and the other range types) iterable.

I've used the surrogate range magic numbers as magic numbers here rather than e.g. a `const SURROGATE_RANGE = 0xD800..0xE000` because these numbers appear to be used as magic numbers elsewhere and there doesn't exist constants for them yet. These files definitely aren't where surrogate range constants should live.

`ExactSizeIterator` is not implemented because `0x10FFFF` is bigger than fits in a `usize == u16`. However, given we already provide some `ExactSizeIterator` that are not correct on 16 bit targets, we might still want to consider providing it for `Range`[`Inclusive`]`<char>`, as it is definitely _very_ convenient. (At the very least, we want to make sure `.count()` doesn't bother iterating the range.)

The second commit in this PR changes a call to `Step::forward` to use `Step::forward_unchecked` in `RangeInclusive::next`. This is because without this patch, iteration over all codepoints (`'\0'..=char::MAX`) does not successfully optimize out the panicking branch. This was mentioned in the PR that updated `Step` to its current design, but was deemed not yet necessary as it did not impact codegen for integral types.

More of `Range*`'s implementations' calls to `Step` methods will probably want to see if they can use the `_unchecked` version as (if) we open up `Step` to being implemented on more types.

---

cc @rust-lang/libs, this is insta-stable and a fairly significant addition to `Range*`'s capabilities; this is the first instance of a noncontinuous domain being iterable with `Range` (or, well, anything other than primitive integers). I don't think this needs a full RFC, but it should definitely get some decent eyes on it.

NVPTX support for new asm!

This PR implements the new `asm!` syntax for the `nvptx64-nvidia-cuda` target.

r? @Amanieu