Currently it copies a `KleeneOp` and a `Token` out of a
`SequenceRepetition`. It's better to store a reference to the
`SequenceRepetition`, which is now possible due to #95159 having changed
the lifetimes.
The `Lrc` is only relevant within `transcribe()`. There, the `Lrc` is
helpful for the non-`NtTT` cases, because the entire nonterminal is
cloned. But for the `NtTT` cases the inner token tree is cloned (a full
clone) and so the `Lrc` is of no help.
This commit splits the `NtTT` and non-`NtTT` cases, avoiding the useless
`Lrc` in the former case, for the following effect on macro-heavy
crates.
- It reduces the total number of allocations a lot.
- It increases the size of some of the remaining allocations.
- It doesn't affect *peak* memory usage, because the larger allocations
are short-lived.
This overall gives a speed win.
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}`.
update Termination trait docs
this pr add some statement about intending to provide `Termination` trait only on standard library's runtime.
from #93448
r? `@Lokathor`
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`
Preserve the Windows `GetLastError` error in `HandleOrInvalid`.
In the `TryFrom<HandleOrInvalid> for OwnedHandle` and
`TryFrom<HandleOrNull> for OwnedHandle` implemenations, `forget` the
owned handle on the error path, to avoid calling `CloseHandle` on an
invalid handle. It's harmless, except that it may overwrite the
thread's `GetLastError` error.
r? `@joshtriplett`
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.
Rollup of 6 pull requests
Successful merges:
- #95074 (Refactor: use `format-args-capture` and remove unnecessary nested if blocks in some parts of `rust_passes`)
- #95085 (Return err instead of ICE)
- #95116 (Add needs-* directives to many tests)
- #95129 (Remove animation on source sidebar)
- #95166 (Update the unstable book with the new `values()` form of check-cfg)
- #95175 (move `adt_const_params` to its own tracking issue)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
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
Don't run UB in test suite
This splits `ui/unsafe/union.rs` to make it so only the non-UB parts are run. It also means we can do more testing of the location of error messages (which are a bit different with the THIR unsafety checker). `union-modification.rs` has no UB (according to Miri), and `union.rs` has errors (but would have UB if not for those errors).
Closes#95075.
r? `@bjorn3`
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.
In the `TryFrom<HandleOrInvalid> for OwnedHandle` and
`TryFrom<HandleOrNull> for OwnedHandle` implemenations, `forget` the
owned handle on the error path, to avoid calling `CloseHandle` on an
invalid handle. It's harmless, except that it may overwrite the
thread's `GetLastError` error.
