Inspired by this internals thread: https://internals.rust-lang.org/t/rc-optimization-on-64-bit-targets/16362

[The generated assembly is a bit smaller](https://rust.godbolt.org/z/TeTnf6144) and is a more efficient usage of the CPU's instruction cache. `unlikely` doesn't impact any of the small artificial tests I've done, but I've included it in case it might help more complex scenarios when this is inlined.

All other ABIs are left unstable for now.

cc rust-lang#64926

Since September, the toolchain has not been generating reliable DWARF
information for static variables when LTO is on. This has affected
projects in the embedded space where the use of LTO is typical. In our
case, it has kept us from bumping past the 2021-09-22 nightly toolchain
lest our debugger break. This has been a pretty dramatic regression for
people using debuggers and static variables. See rust-lang#90357 for more info
and a repro case.

This commit is a mechanical revert of
d5de680 from PR rust-lang#89041, which caused
the issue. (Note on that PR that the commit's author has requested it be
reverted.)

I have locally verified that this fixes rust-lang#90357 by restoring the
functionality of both the repro case I posted on that bug, and debugger
behavior on real programs. There do not appear to be test cases for this
in the toolchain; if I've missed them, point me at 'em and I'll update
them.

- Re-enabled basic-types-globals which has been disabled since 2018
- Updated its now-rotted assertions about GDB's output to pass
- Rewrote header comment describing some previous state of GDB behavior
  that didn't match either the checked-in assertions _or_ the current
  behavior, and so I assume has just been wrong for some time.
- Copy-pasta'd the test into a version that uses LTO to check for
  regression on rust-lang#90357, because I don't see a way to matrix the same
  test into several build configurations.

I managed to break this in rust-lang#95449.
I am not quite sure why this is the correct fix, but it doesn't break `doc --stage 0`
and is strictly closer to the previous behavior.

Previously, rustdoc would error with strange issues because of the mismatched sysroot:
```
error[E0460]: found possibly newer version of crate `std` which `rustc_span` depends on
  --> /home/jnelson/rust-lang/rust/compiler/rustc_lint_defs/src/lib.rs:14:5
   |
14 | use rustc_span::{sym, symbol::Ident, Span, Symbol};
   |     ^^^^^^^^^^
   |
   = note: perhaps that crate needs to be recompiled?
   = note: the following crate versions were found:
           crate `std`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-ff9290e971253a38.rlib
           crate `std`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-ff9290e971253a38.so
           crate `rustc_span`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/deps/librustc_span-ed11dce30c1766f9.rlib
```

update: actions/checkout@v2 to actions/checkout@v3 for all yaml files

Revert "update: actions/checkout@v2 to actions/checkout@v3 for all yaml files"

This reverts commit 7445e582b900f0f56f5f2bd9036aacab97ef28e9.

change GitHub Actions version v2 to v3

change GitHub Actions

…pnkfelix

Only add codegen backend to dep info if -Zbinary-dep-depinfo is used

I am currently migrating the cg_clif build system from using a binary linked to the codegen backend as rustc replacement to passing `-Zcodegen-backend` instead. Without this PR this would force cargo to rebuild the sysroot on any change to the codegen backend even if I explicitly specify that I want it to be preserved, which would make development of cg_clif a lot slower. If you still want to have changes to the codegen backend invalidate the cargo build cache you can explicitly specify `-Zbinary-dep-depinfo`.

cc `@eddyb` as the codegen backend was initially added to the depinfo for rust-gpu.

Create (unstable) 2024 edition

[On Zulip](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Deprecating.20macro.20scoping.20shenanigans/near/272860652), there was a small aside regarding creating the 2024 edition now as opposed to later. There was a reasonable amount of support and no stated opposition.

This change creates the 2024 edition in the compiler and creates a prelude for the 2024 edition. There is no current difference between the 2021 and 2024 editions. Cargo and other tools will need to be updated separately, as it's not in the same repository. This change permits the vast majority of work towards the next edition to proceed _now_ instead of waiting until 2024.

For sanity purposes, I've merged the "hello" UI tests into a single file with multiple revisions. Otherwise we'd end up with a file per edition, despite them being essentially identical.

``@rustbot`` label +T-lang +S-waiting-on-review

Not sure on the relevant team, to be honest.

Check var scope if it exist

Fixes rust-lang#92893.

Added helper function to check the scope of a variable, if it doesn't have a scope call delay_span_bug, which avoids us trying to get a block/scope that doesn't exist.

Had to increase `ROOT_ENTRY_LIMIT` was getting tidy error

Parse inner attributes on inline const block

According to rust-lang#84414 (comment), inner attributes are intended to be supported *"in all containers for statements (or some subset of statements)"*.

This PR adds inner attribute parsing and pretty-printing for inline const blocks (rust-lang#76001), which contain statements just like an unsafe block or a loop body.

```rust
let _ = const {
    #![allow(...)]

    let x = ();
    x
};
```

Optimize RcInnerPtr::inc_strong()/inc_weak() instruction count

Inspired by this internals thread: https://internals.rust-lang.org/t/rc-optimization-on-64-bit-targets/16362

[The generated assembly is a bit smaller](https://rust.godbolt.org/z/TeTnf6144) and is a more efficient usage of the CPU's instruction cache. `unlikely` doesn't impact any of the small artificial tests I've done, but I've included it in case it might help more complex scenarios when this is inlined.

… r=pnkfelix

Stablize `const_extern_fn` for "Rust" and "C"

All other ABIs are left unstable for now.

cc rust-lang#64926

… r=pnkfelix

Revert "Work around invalid DWARF bugs for fat LTO"

Since September, the toolchain has not been generating reliable DWARF
information for static variables when LTO is on. This has affected
projects in the embedded space where the use of LTO is typical. In our
case, it has kept us from bumping past the 2021-09-22 nightly toolchain
lest our debugger break. This has been a pretty dramatic regression for
people using debuggers and static variables. See rust-lang#90357 for more info
and a repro case.

This commit is a mechanical revert of
d5de680 from PR rust-lang#89041, which caused
the issue. (Note on that PR that the commit's author has requested it be
reverted.)

I have locally verified that this fixes rust-lang#90357 by restoring the
functionality of both the repro case I posted on that bug, and debugger
behavior on real programs. There do not appear to be test cases for this
in the toolchain; if I've missed them, point me at 'em and I'll update
them.

only downgrade selection Error -> Ambiguous if type error is in predicate

That is, we don't care if there's a TypeError type in the ParamEnv.

Fixes rust-lang#95408

…inline, r=oli-obk

Inline `shallow_resolve_ty` into `ShallowResolver`

addresses fixme I found in infcx

…ubilee

implement SIMD gather/scatter via vector getelementptr

Fixes rust-lang/portable-simd#271

However, I don't *really* know what I am doing here... Cc `@workingjubilee` `@calebzulawski`

I didn't do anything for cranelift -- `@bjorn3` not sure if it's okay for that backend to temporarily break. I'm happy to cherry-pick a patch that adds cranelift support. :)

…Simulacrum

Fix `x test --doc --stage 0 library/std`

I managed to break this in rust-lang#95449.
I am not quite sure why this is the correct fix, but it doesn't break `doc --stage 0`
and is strictly closer to the previous behavior.

Previously, rustdoc would error with strange issues because of the mismatched sysroot:
```
error[E0460]: found possibly newer version of crate `std` which `rustc_span` depends on
  --> /home/jnelson/rust-lang/rust/compiler/rustc_lint_defs/src/lib.rs:14:5
   |
14 | use rustc_span::{sym, symbol::Ident, Span, Symbol};
   |     ^^^^^^^^^^
   |
   = note: perhaps that crate needs to be recompiled?
   = note: the following crate versions were found:
           crate `std`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-ff9290e971253a38.rlib
           crate `std`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-ff9290e971253a38.so
           crate `rustc_span`: /home/jnelson/rust-lang/rust/build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/deps/librustc_span-ed11dce30c1766f9.rlib
```

…ylan-DPC

couple of clippy::complexity fixes

…Dylan-DPC

[test] Add test cases of untested functions for BTreeSet

- add [`is_superset()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.is_superset) and [`remove()`](https://doc.rust-lang.org/std/collections/struct.BTreeSet.html#method.remove) test cases for BTreeSet since these functions has no test cases.

…hub-action-version, r=pietroalbini

Update GitHub Actions actions/checkout Version v2 -> v3

Update `actions/checkout@v2` to `actions/checkout@v3` because of Node12 will be out of life after Aril 30, 2022 [[Reference](https://nodejs.org/en/about/releases/)].
`actions/xxxx@v3` use Node16 whose support lasts until April 30, 2024.

…=lnicola

⬆️ rust-analyzer

r? `@ghost`

docs: Update tests chapter for Termination stabilization

A small update for the docs of `#[test]` functions as a result of the `Termination` stabilization in rust-lang#93840.