This change makes it so, instead of mixing string distance with
type unification, function signature search works by
mapping names to IDs at the start, reporting to the user any
cases where it had to make corrections, and then matches with
IDs when going through the items.

This only changes function searches. Name searches are left alone,
and corrections are only done when there's a single item in the
search query.

This commit adds cross-language LLVM Control Flow Integrity (CFI)
support to the Rust compiler by adding the
`-Zsanitizer-cfi-normalize-integers` option to be used with Clang
`-fsanitize-cfi-icall-normalize-integers` for normalizing integer types
(see https://reviews.llvm.org/D139395).

It provides forward-edge control flow protection for C or C++ and Rust
-compiled code "mixed binaries" (i.e., for when C or C++ and Rust
-compiled code share the same virtual address space). For more
information about LLVM CFI and cross-language LLVM CFI support for the
Rust compiler, see design document in the tracking issue rust-lang#89653.

Cross-language LLVM CFI can be enabled with -Zsanitizer=cfi and
-Zsanitizer-cfi-normalize-integers, and requires proper (i.e.,
non-rustc) LTO (i.e., -Clinker-plugin-lto).

This commit updates the documentation for the LLVM Control Flow
Integrity (CFI) support in the Rust compiler.

... with this convertions some tests fail :(

FFX has new builtin support for isolating the daemon's environment. This
switches the manual isolation originally written to that new builtin
feature.

…risDenton

Implement tuple<->array convertions via `From`

This PR adds the following impls that convert between homogeneous tuples and arrays of the corresponding lengths:
```rust
impl<T> From<[T; 1]> for (T,) { ... }
impl<T> From<[T; 2]> for (T, T) { ... }
/* ... */
impl<T> From<[T; 12]> for (T, T, T, T, T, T, T, T, T, T, T, T) { ... }

impl<T> From<(T,)> for [T; 1] { ... }
impl<T> From<(T, T)> for [T; 2] { ... }
/* ... */
impl<T> From<(T, T, T, T, T, T, T, T, T, T, T, T)> for [T; 12] { ... }
```

IMO these are quite uncontroversial but note that they are, just like any other trait impls, insta-stable.

Add cross-language LLVM CFI support to the Rust compiler

This PR adds cross-language LLVM Control Flow Integrity (CFI) support to the Rust compiler by adding the `-Zsanitizer-cfi-normalize-integers` option to be used with Clang `-fsanitize-cfi-icall-normalize-integers` for normalizing integer types (see https://reviews.llvm.org/D139395).

It provides forward-edge control flow protection for C or C++ and Rust -compiled code "mixed binaries" (i.e., for when C or C++ and Rust -compiled code share the same virtual address space). For more information about LLVM CFI and cross-language LLVM CFI support for the Rust compiler, see design document in the tracking issue rust-lang#89653.

Cross-language LLVM CFI can be enabled with -Zsanitizer=cfi and -Zsanitizer-cfi-normalize-integers, and requires proper (i.e., non-rustc) LTO (i.e., -Clinker-plugin-lto).

Thank you again, `@bjorn3,` `@nikic,` `@samitolvanen,` and the Rust community for all the help!

…ou-se

Replace generic thread parker with explicit no-op parker

With rust-lang#98391 merged, all platforms supporting threads now have their own parking implementations. Therefore, the generic implementation can be removed. On the remaining platforms (really just WASM without atomics), parking is not supported, so calls to `thread::park` now return instantly, which is [allowed by their API](https://doc.rust-lang.org/nightly/std/thread/fn.park.html). This is a change in behaviour, as spurious wakeups do not currently occur since all platforms guard against them. It is invalid to depend on this, but I'm still going to tag this as libs-api for confirmation.

`@rustbot` label +T-libs +T-libs-api +A-atomic

r? rust-lang/libs

…ions, r=GuillaumeGomez

rustdoc: restructure type search engine to pick-and-use IDs

Fixes rust-lang#110029

Preview: https://notriddle.com/rustdoc-demo-html-3/search-corrections/std/index.html?search=-%3E%20streaming

![image](https://user-images.githubusercontent.com/1593513/233494900-ae77d5b4-e395-41f8-bbac-53ee55bb4a76.png)

This change makes it so, instead of mixing string distance with type unification, function signature search works by mapping names to IDs at the start, reporting to the user any cases where it had to make corrections, and then matches with IDs when going through the items.

This only changes function searches. Name searches are left alone, and corrections are only done when there's a single item in the search query.

Update ICU4X to 1.2

Was released a couple weeks ago.

Also needed to make progress on rust-lang#109302 (though this PR does not achieve that part just yet)

Constify slice flatten method

ACP: rust-lang/libs-team#218

…errors

rustc_middle: Fix `opt_item_ident` for non-local def ids

Noticed while working on rust-lang#110855.

…n, r=tmandry

Use builtin FFX isolation for Fuchsia test runner

FFX has new builtin support for isolating the daemon's environment. This switches the manual isolation originally written to that new builtin feature.

r? `@tmandry`