Instead of suggesting that the body always replace the last character on the
line, presuming it must be a semicolon, the parser should instead check what
the last character is, and append the body if it is anything else.
Fixes#83104
Arm's FEAT_FP and Feat_AdvSIMD describe the same thing on AArch64:
The Neon unit, which handles both floating point and SIMD instructions.
Moreover, a configuration for AArch64 must include both or neither.
Arm says "entirely proprietary" toolchains may omit floating point:
https://developer.arm.com/documentation/102374/0101/Data-processing---floating-point
In the Programmer's Guide for Armv8-A, Arm says AArch64 can have
both FP and Neon or neither in custom implementations:
https://developer.arm.com/documentation/den0024/a/AArch64-Floating-point-and-NEON
In "Bare metal boot code for Armv8-A", enabling Neon and FP
is just disabling the same trap flag:
https://developer.arm.com/documentation/dai0527/a
In an unlikely future where "Neon and FP" become unrelated,
we can add "[+-]fp" as its own feature flag.
Until then, we can simplify programming with Rust on AArch64 by
folding both into "[+-]neon", which is valid as it supersets both.
"[+-]neon" is retained for niche uses such as firmware, kernels,
"I just hate floats", and so on.
Introduce `TtParser`
These commits make a number of changes to declarative macro expansion, resulting in code that is shorter, simpler, and faster.
Best reviewed one commit at a time.
r? `@petrochenkov`
As its name suggests, `TokenTreeOrTokenTreeSlice` is either a single
`TokenTree` or a slice of them. It has methods `len` and `get_tt` that
let it be treated much like an ordinary slice. The reason it isn't an
ordinary slice is that for `TokenTree::Delimited` the open and close
delimiters are represented implicitly, and when they are needed they are
constructed on the fly with `Delimited::{open,close}_tt`, rather than
being present in memory.
This commit changes `Delimited` so the open and close delimiters are
represented explicitly. As a result, `TokenTreeOrTokenTreeSlice` is no
longer needed and `MatcherPos` and `MatcherTtFrame` can just use an
ordinary slice. `TokenTree::{len,get_tt}` are also removed, because they
were only needed to support `TokenTreeOrTokenTreeSlice`.
The change makes the code shorter and a little bit faster on benchmarks
that use macro expansion heavily, partly because `MatcherPos` is a lot
smaller (less data to `memcpy`) and partly because ordinary slice
operations are faster than `TokenTreeOrTokenTreeSlice::{len,get_tt}`.
Suggest constraining param for unary ops when missing trait impl
This PR adds a suggestion of constraining param for unary ops `-` and `!` when the corresponding trait implementation
is missing.
Fixs #94543.
BTW, this is my first time to touch rustc, please correct me if I did anything wrong.
rename LocalState::Uninitialized to Unallocated
This is to avoid confusion with `Uninit` as in `ScalarMaybeUninit`, which is very different.
r? `@oli-obk`
Inline some parser functions
Some crates that do a lot of complex declarative macro expansion spend a lot of time parsing (and reparsing) tokens. These commits inline some functions for some minor speed wins.
r? `@ghost`
Disable almost certainly unsound early otherwise branch MIR opt
Originally thought this was just an MIR semantics issue, but it's not.
r? rust-lang/mir-opt
The call site within `Parser::bump` is hot.
Also add an inline annotation to `Parser::next_tok`. It was already
being inlined by the compiler; this just makes sure that continues.
Return err instead of ICE
Having `escaping_bound_vars` results in ICE when trying to create `ty::Binder::dummy`, to avoid it we return err like the line above. I think this requires a more sophisticated fix, I would love to investigate if mentorship is available 🤓Fixes#95023 and #85350
suggest removing type ascription in bad parsing position
Not sure how to test this with the non-nightly suggestion. Didn't add a new UI test because it already manifests in an existing UI test.
Fixes#95014
By putting them in `TtParser`, we can reuse them for every rule in a
macro. With that done, they can be `SmallVec` instead of `Vec`, and this
is a performance win because these vectors are hot and `SmallVec`
operations are a bit slower due to always needing an "inline or heap?"
check.
This type was a small performance win for `html5ever`, which uses a
macro with hundreds of very simple rules that don't contain any
metavariables. But this type is complicated (extra lifetimes) and
perf-neutral for macros that do have metavariables.
This commit removes `MatcherPosHandle`, simplifying things a lot. This
increases the allocation rate for `html5ever` and similar cases a bit,
but makes things easier for follow-up changes that will improve
performance more than what we lost here.
