This commit updates rustc, with an applicable LLVM version, to use
LLVM's new `llvm.fpto{u,s}i.sat.*.*` intrinsics to implement saturating
floating-point-to-int conversions. This results in a little bit tighter
codegen for x86/x86_64, but the main purpose of this is to prepare for
upcoming changes to the WebAssembly backend in LLVM where wasm's
saturating float-to-int instructions will now be implemented with these
intrinsics.
This change allows simplifying a good deal of surrounding code, namely
removing a lot of wasm-specific behavior. WebAssembly no longer has any
special-casing of saturating arithmetic instructions and the need for
`fptoint_may_trap` is gone and all handling code for that is now
removed. This means that the only wasm-specific logic is in the
`fpto{s,u}i` instructions which only get used for "out of bounds is
undefined behavior". This does mean that for the WebAssembly target
specifically the Rust compiler will no longer be 100% compatible with
pre-LLVM 12 versions, but it seems like that's unlikely to be relied on
by too many folks.
Note that this change does immediately regress the codegen of saturating
float-to-int casts on WebAssembly due to the specialization of the LLVM
intrinsic not being present in our LLVM fork just yet. I'll be following
up with an LLVM update to pull in those patches, but affects a few other
SIMD things in flight for WebAssembly so I wanted to separate this change.
Eventually the entire `cast_float_to_int` function can be removed when
LLVM 12 is the minimum version, but that will require sinking the
complexity of it into other backends such as Cranelfit.
rustdoc: Reduce visual weight of attributes.
Followup from #83337. As part of that PR, we stopped hiding attributes behind a toggle, because most things have just zero or one attributes. However, this made clear that the current rendering of attributes emphasizes them a lot, which distracts from function signatures. This PR changes their color of attributes to be the same as the toggles, and reduces their font weight.
This also removes `#[lang]` from the list of ALLOWED_ATTRIBUTES. This attribute is an implementation detail rather than part of the public-facing documentation.
Demo at https://hoffman-andrews.com/rust/de-emph-attr/std/string/struct.String.html#method.trim
Stablize `non-ascii-idents`
This is the stablization PR for RFC 2457. Currently this is waiting on fcp in [tracking issue](https://github.com/rust-lang/rust/issues/55467).
r? `@Manishearth`
Add `Unsupported` to `std::io::ErrorKind`
I noticed a significant portion of the uses of `ErrorKind::Other` in std is for unsupported operations.
The notion that a specific operation is not available on a target (and will thus never succeed) seems semantically distinct enough from just "an unspecified error occurred", which is why I am proposing to add the variant `Unsupported` to `std::io::ErrorKind`.
**Implementation**:
The following variant will be added to `std::io::ErrorKind`:
```rust
/// This operation is unsupported on this platform.
Unsupported
```
`std::io::ErrorKind::Unsupported` is an error returned when a given operation is not supported on a platform, and will thus never succeed; there is no way for the software to recover. It will be used instead of `Other` where appropriate, e.g. on wasm for file and network operations.
`decode_error_kind` will be updated to decode operating system errors to `Unsupported`:
- Unix and VxWorks: `libc::ENOSYS`
- Windows: `c::ERROR_CALL_NOT_IMPLEMENTED`
- WASI: `wasi::ERRNO_NOSYS`
**Stability**:
This changes the kind of error returned by some functions on some platforms, which I think is not covered by the stability guarantees of the std? User code could depend on this behavior, expecting `ErrorKind::Other`, however the docs already mention:
> Errors that are `Other` now may move to a different or a new `ErrorKind` variant in the future. It is not recommended to match an error against `Other` and to expect any additional characteristics, e.g., a specific `Error::raw_os_error` return value.
The most recent variant added to `ErrorKind` was `UnexpectedEof` in `1.6.0` (almost 5 years ago), but `ErrorKind` is marked as `#[non_exhaustive]` and the docs warn about exhaustively matching on it, so adding a new variant per se should not be a breaking change.
The variant `Unsupported` itself could be marked as `#[unstable]`, however, because this PR also immediately uses this new variant and changes the errors returned by functions I'm inclined to agree with the others in this thread that the variant should be insta-stabilized.
Don't set fast-math for the SIMD operations we set it for previously
Instead of `fast-math`. `fast-math` implies things like functions not
being able to accept as an argument or return as a result, say, `inf`
which made these functions confusingly named or behaving incorrectly,
depending on how you interpret it. It seems that the intended behaviour
was to set a `afn` flag instead. In doing so we also renamed the
intrinsics to say `_approx` so that it is clear these are not precision
oriented and the users can act accordingly.
Fixes#84268
Deprecate the core::raw / std::raw module
It only contains the `TraitObject` struct which exposes components of wide pointer. Pointer metadata APIs are designed to replace this: https://github.com/rust-lang/rust/issues/81513
Add some #[inline(always)] to arithmetic methods of integers
I tried to add it only to methods which return results of intrinsics and don't have any branching.
Branching could made performance of debug builds (`-Copt-level=0`) worse.
Main goal of changes is allowing wider optimizations in `-Copt-level=1`.
Closes: https://github.com/rust-lang/rust/issues/75598
r? `@nagisa`
Rollup of 4 pull requests
Successful merges:
- #83237 (rustdoc: use more precise relative URLs)
- #84150 (rustdoc: move some search code into search.js)
- #84203 (rustdoc: Give a more accurate span for anchor failures)
- #84257 (Add documentation to help people find `Ipv4Addr::UNSPECIFIED`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
`fast-math` implies things like functions not being able to accept as an
argument or return as a result, say, `inf` which made these functions
confusingly named or behaving incorrectly, depending on how you
interpret it. Since the time when these intrinsics have been implemented
the intrinsics user's (stdsimd) approach has changed significantly and
so now it is required that these intrinsics operate normally rather than
in "whatever" way.
Fixes#84268
Add documentation to help people find `Ipv4Addr::UNSPECIFIED`
People looking for `INADDR_ANY` don't always find `Ipv4Addr::UNSPECIFIED`;
add some documentation to help.
rustdoc: move some search code into search.js
This reduces main.s from 3094 lines to 1587. Also it saves some bytes
of download in the case where search isn't used.
There were a fair number of variables that needed to be accessible in
both main.js and search.js, but I didn't want to put too many symbols in
the global namespace, so I consolidated much of the search-related
state and functions into a new object `window.searchState`.
Demo at https://hoffman-andrews.com/rust/move-search/std/?search=foo
rustdoc: use more precise relative URLs
This is a fairly large diff, and will probably conflict with https://github.com/rust-lang/rust/pull/82815 since it reduces (but does not eliminate) the use of the old depth variable.
Instead of using a depth counter and adding "../" to get to the top, this commit makes rustdoc actually compare the path of what it's linking from to the path that it's linking to. This makes the resulting HTML shorter.
Here's a comparison of one of the largest (non-source) files in the Rust standard library docs (about 4% improvement before gzipping).
$ wc -c struct.Wrapping.old.html struct.Wrapping.new.html
2387389 struct.Wrapping.old.html
2298538 struct.Wrapping.new.html
Most if it can be efficiently gzipped away.
$ wc -c struct.Wrapping.old.html.gz struct.Wrapping.new.html.gz
70679 struct.Wrapping.old.html.gz
70050 struct.Wrapping.new.html.gz
But it also makes a difference in the final DOM size, reducing it from 91MiB to 82MiB.
Instead of using a depth counter and adding "../" to get to the top,
this commit makes rustdoc actually compare the path of what it's
linking from to the path that it's linking to. This makes the resulting
HTML shorter.
Here's a comparison of one of the largest (non-source) files in the
Rust standard library docs (about 4% improvement before gzipping).
$ wc -c struct.Wrapping.old.html struct.Wrapping.new.html
2387389 struct.Wrapping.old.html
2298538 struct.Wrapping.new.html
Most if it can be efficiently gzipped away.
$ wc -c struct.Wrapping.old.html.gz struct.Wrapping.new.html.gz
70679 struct.Wrapping.old.html.gz
70050 struct.Wrapping.new.html.gz
But it also makes a difference in the final DOM size, reducing it from 91MiB to 82MiB.
Error when compiletest is passed duplicate revisions
Currently, we allow the user to write things like
'// revisions: rpass1 rpass1', which will not test what they were
intending to test.
rustdoc: get rid of unused path printing code
The code for printing a raw path is only used in utils.rs, which only prints the alternative (non-HTML) format. Path has
a function that does the same thing without HTML support, so use that instead.
fix incomplete diagnostic notes when closure returns conflicting for genric type
fixes#84128
Correctly report the span on for conflicting return type in closures
Builtin derive macros: fix error with const generics default
This fixes a bug where builtin derive macros (like Clone, Debug) would basically copy-paste the default from a const generic, causing a compile error with very confusing message - it would say defaults are not allowed in impl blocks, while pointing at struct/enum/union definition.
Detect when suggested paths enter extern crates more rigorously
When reporting resolution errors, the compiler tries to avoid suggesting importing inaccessible paths from other crates. However, the search for suggestions only recognized when it was entering a crate root directly, and so failed to recognize a path like `crate::module::private_item`, where `module` was imported from another crate with `use other_crate::module`, as entering another crate.
Fixes#80079Fixes#84081
rustdoc: clean up and test macro visibility print
This fixes the overly-complex invariant mentioned in <https://github.com/rust-lang/rust/pull/83237#issuecomment-815346570>, where the macro source can't have any links in it only because the cache hasn't been populated yet.
