[win][arm64] Remove 'Arm64 Hazard' undocumented MSVC option and instead disable problematic test
PR #140758 added the undocumented `/arm64hazardfree` MSVC linker flag to work around a test failure where LLVM generated code that would trip a hazard in an outdated ARM processor.
Adding this flag caused issues with LLD, as it doesn't recognize it.
Rethinking the issue, using the undocumented flag seems like the incorrect solution: there's no guarantee that the flag won't be removed in the future, or change its meaning.
Instead, I've disabled the problematic test for Arm64 Windows and have filed a bug with the MSVC team to have the check removed: <https://developercommunity.microsoft.com/t/Remove-checking-for-and-fixing-Cortex-A/10905134>
This PR supersedes #140977
r? ```@jieyouxu```
Remove #![feature(let_chains)] from library and src/librustdoc
PR https://github.com/rust-lang/rust/pull/132833 has stabilized the `let_chains` feature. This PR removes the last occurences from the library, the compiler, and librustdoc (also because #140887 missed the conditional in one of the crates as it was behind the "rustc" feature).
We keep `core` as exercise for the future as updating it is non-trivial (see PR thread).
Add per page TOC in the `rustc` book
This PR adds per page Table of Content (TOC) in the `rustc` book (to be extended in the future to our other books).
The goal is to easy the navigation inside the page by providing quick overview of the page content and our position inside that page.
That functionality is unfortunately not available natively in `mdbook`, which prompted community members to create [mdBook-pagetoc](https://github.com/JorelAli/mdBook-pagetoc/) (which this PR is heavily inspired by). It's "only" a JS file (to handle the TOC) and a CSS file (to handle the margin, colors, screen size, ...), there is no "post-processor" needed (in mdbook sense).
Live preview at: http://urgau.rf.gd/book
r? ```@jieyouxu```
Fast path for `register_region_obligation`
If a type has no params, infer, placeholder, or non-`'static` free regions, then we can skip registering outlives obligations since the type has no components which affect lifetime checking in an interesting way.
move expensive layout sanity check to debug assertions
It is [hard to fix](https://github.com/rust-lang/rust/issues/141006#issuecomment-2883415000) the slowness in the uninhabitedness computation for very big types but we can fix the very specific case of them being called during the layout sanity checks, as described in #140944.
So this PR moves this uninhabitedness check to the other expensive layout sanity checks that are ran under `debug_assertions`.
It makes building the `lemmy_api_routes` crate's self-profile `layout_of` query go from
```
+--------------------------------------------------------+-----------+-----------------+----------+------------+---------------------------------+
| Item | Self time | % of total time | Time | Item count | Incremental result hashing time |
+--------------------------------------------------------+-----------+-----------------+----------+------------+---------------------------------+
| layout_of | 63.02s | 41.895 | 244.26s | 123703 | 50.30ms |
+--------------------------------------------------------+-----------+-----------------+----------+------------+---------------------------------+
```
on master (2m17s total), to
```
| layout_of | 330.21ms | 0.372 | 26.90s | 123703 | 53.19ms |
```
with this PR (1m15s total).
(Note that the [perf run results](https://github.com/rust-lang/rust/pull/141039#issuecomment-2884688756) below look a bit better than [an earlier run](https://perf.rust-lang.org/compare.html?start=4eca99a18eab3d4e28ed1ce3ee620d442955a470&end=c4a00993f8ee02c7565e7be652608817ea2fb97d&stat=instructions:u) I did in another PR. There may be some positive noise there, or post-merge results could differ a bit)
Since we discussed this today, r? `@compiler-errors` — and cc `@lcnr` and `@RalfJung.`
Merge mir query analysis invocations
r? `@ghost`
same thing as https://github.com/rust-lang/rust/pull/140854 just a different set of queries
Doing this in general has some bad cache coherence issues because the query caches are laid out in Vec<QueryResult> lists per query where each index refers to a DefId in the same order as we're iterating. Iterating two or more lists at the same time does have cache issues, so I want to poke a bit at it to see if we can't merge just a few of them at a time.
Initial implementation of `core_float_math`
Since [1], `compiler-builtins` makes a certain set of math symbols
weakly available on all platforms. This means we can begin exposing some
of the related functions in `core`, so begin this process here.
It is not possible to provide inherent methods in both `core` and `std`
while giving them different stability gates, so standalone functions are
added instead. This provides a way to experiment with the functionality
while unstable; once it is time to stabilize, they can be converted to
inherent.
For `f16` and `f128`, everything is unstable so we can move the inherent
methods.
The following are included to start:
* floor
* ceil
* round
* round_ties_even
* trunc
* fract
* mul_add
* div_euclid
* rem_euclid
* powi
* sqrt
* abs_sub
* cbrt
These mirror the set of functions that we have in `compiler-builtins`
since [1], with the exception of `powi` that has been there longer.
Details for each of the changes is in the commit messages.
Tracking issue: https://github.com/rust-lang/rust/issues/137578
[1]: https://github.com/rust-lang/compiler-builtins/pull/763
try-job: aarch64-gnu
tru-job: armhf-gnu
try-job: i686-msvc-1
try-job: test-various
try-job: x86_64-mingw-1
try-job: x86_64-mingw-2
