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Optimize character escaping. #124307

Merged
merged 3 commits into from
May 15, 2024
Merged

Optimize character escaping. #124307

merged 3 commits into from
May 15, 2024

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reitermarkus
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Allow optimization of panicking branch in EscapeDebug, see #121805.

r? @joboet

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Apr 23, 2024
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joboet commented Apr 23, 2024 •
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I'm so sorry, I had another look at this and found that my analysis was incorrect: I forgot to switch the compiler...

The actual cause (fingers crossed) is in EscapeIterInner::next (and the same applies to its next_back and as_ascii methods). The compiler does not know about this range invariant:

rust/library/core/src/escape.rs

Line 70 in 40dcd79

// Invariant: alive.start <= alive.end <= N.

so it cannot optimize out the branch checks here:

rust/library/core/src/escape.rs

Line 102 in 40dcd79

self.alive.next().map(|i| self.data[usize::from(i)].to_u8())

(Godbolt example)

The ufmt example iterates over an escaped EscapeDebug and therefore calls EscapeIterInner::next, leading to the panic branch.

You are welcome to fix this in this PR, but can also open another one and just assign me.

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reitermarkus commented Apr 25, 2024 •
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@joboet, I have now refactored EscapeIterInner to better contain the alive range invariant and changed the index operations to use get_unchecked.

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I love the approach, encapsulating the invariant is a very good idea. One small issue left.

I changed the PR title to make it fit the contents, feel free to adapt it further.

library/core/src/escape.rs Outdated Show resolved Hide resolved
@joboet joboet changed the title Inline EscapeDebug::size_hint. Optimize character escaping Apr 30, 2024
@joboet joboet added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 1, 2024
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@rustbot ready

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels May 1, 2024
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reitermarkus commented May 1, 2024 •
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@joboet, I now reverted to using Range<u8> since that version generates fewer instructions, and also added a hint when converting char to u32 which allows optimizing the index operations.

@reitermarkus reitermarkus requested a review from joboet May 1, 2024 15:57
@joboet joboet added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 2, 2024
@reitermarkus reitermarkus force-pushed the escape-debug-size-hint-inline branch from 46c9a9a to ec1775d Compare May 8, 2024 20:04
@reitermarkus reitermarkus changed the title Optimize character escaping Optimize character escaping. May 8, 2024
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@reitermarkus reitermarkus force-pushed the escape-debug-size-hint-inline branch from ec1775d to 57c84a5 Compare May 8, 2024 20:08
@reitermarkus reitermarkus requested a review from joboet May 8, 2024 20:23
@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels May 8, 2024
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@rustbot ready

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This looks great, I just have two small nits left.

library/core/src/char/mod.rs Outdated Show resolved Hide resolved
library/core/src/char/mod.rs Outdated Show resolved Hide resolved
library/core/src/ascii.rs Outdated Show resolved Hide resolved
@reitermarkus reitermarkus force-pushed the escape-debug-size-hint-inline branch from 57c84a5 to 4edf12d Compare May 9, 2024 15:04
@reitermarkus reitermarkus requested a review from joboet May 9, 2024 15:14
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joboet commented May 15, 2024

Cool stuff, thank you!
@bors r+

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bors commented May 15, 2024

📌 Commit 4edf12d has been approved by joboet

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 15, 2024
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bors added a commit to rust-lang-ci/rust that referenced this pull request May 15, 2024
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Auto merge of rust-lang#125144 - fmease:rollup-4uft293, r=fmease
ade234d 
Rollup of 6 pull requests

Successful merges:

 - rust-lang#124307 (Optimize character escaping.)
 - rust-lang#124975 (Use an helper to move the files)
 - rust-lang#125027 (Migrate `run-make/c-link-to-rust-staticlib` to `rmake`)
 - rust-lang#125038 (Invert comparison in `uN::checked_sub`)
 - rust-lang#125104 (Migrate `run-make/no-cdylib-as-rdylib` to `rmake`)
 - rust-lang#125137 (MIR operators: clarify Shl/Shr handling of negative offsets)

r? `@ghost`
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@bors bors merged commit 3873a74 into rust-lang:master May 15, 2024
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@rustbot rustbot added this to the 1.80.0 milestone May 15, 2024
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bors commented May 15, 2024

⌛ Testing commit 4edf12d with merge ade234d...

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request May 15, 2024
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Unrolled build for rust-lang#124307
8c4b3c7 
Rollup merge of rust-lang#124307 - reitermarkus:escape-debug-size-hint-inline, r=joboet

Optimize character escaping.

Allow optimization of panicking branch in `EscapeDebug`, see rust-lang#121805.

r? `@joboet`
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fmease commented May 15, 2024 •
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Perf regression. See #125144 (comment)

@joboet joboet mentioned this pull request May 20, 2024
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bors added a commit to rust-lang-ci/rust that referenced this pull request May 20, 2024
@bors
Auto merge of rust-lang#125317 - joboet:optimize_escape, r=<try>
a2f180d 
Optimize `EscapeIterInner`

This optimizes `EscapeIterInner` by using `MaybeUninit` for unused array elements instead of initializing them with `ascii::Char::Null`.

Follow up to rust-lang#124307, CC `@reitermarkus`
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escape_ascii produces 13 fewer instructions:

https://rust.godbolt.org/z/8eob57os8

escape_unicode produces the same number of instructions:

https://rust.godbolt.org/z/zv9f8eb1n

@reitermarkus reitermarkus mentioned this pull request May 20, 2024
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@reitermarkus reitermarkus deleted the escape-debug-size-hint-inline branch May 24, 2024 20:02
celinval added a commit to celinval/rust-dev that referenced this pull request Jun 4, 2024
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rust-lang@1871252fc8 Auto merge of
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rust-lang@734a109998 Rollup merge of
rust-lang#125159 - fmease:allow-unauth-labels-l-pg-z, r=jieyouxu
rust-lang@601e5d199f Rollup merge of
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rust-lang@09156291e5 Rollup merge of
rust-lang#125146 - Oneirical:panic-impl, r=jieyouxu
rust-lang@80f991e09b Rollup merge of
rust-lang#125142 - GuillaumeGomez:migrate-rustdoc-themes, r=jieyouxu
rust-lang@c5b17ec9d2 Rollup merge of
rust-lang#125003 - RalfJung:aligned_alloc, r=cuviper
rust-lang@257d222e4b Improved the
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rust-lang@b21b74b5e6 Auto merge of
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rust-lang@a7484d2e49 fix tidy
rust-lang@cae17ff42b rewrite
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rust-lang@ade234d574 Auto merge of
rust-lang#125144 - fmease:rollup-4uft293, r=fmease
rust-lang@8d38f2fb11 Rollup merge of
rust-lang#125137 - RalfJung:mir-sh, r=scottmcm
rust-lang@2659ff3882 Rollup merge of
rust-lang#125104 - Oneirical:test6, r=jieyouxu
rust-lang@4f7d9d4ad8 Rollup merge of
rust-lang#125038 - ivan-shrimp:checked_sub, r=joboet
rust-lang@2804d4223b Rollup merge of
rust-lang#125027 - Oneirical:c-test-with-remove, r=jieyouxu
rust-lang@2e70bea168 Rollup merge of
rust-lang#124975 - lu-zero:move_file, r=clubby789
rust-lang@3873a74f8a Rollup merge of
rust-lang#124307 - reitermarkus:escape-debug-size-hint-inline, r=joboet
rust-lang@3cb0030fe9 Auto merge of
rust-lang#123413 - petrochenkov:delegmulti2, r=fmease
rust-lang@c765480efe Migrate
`run-make/rustdoc-themes` to new rmake
rust-lang@c87ae947eb Add new `htmldocck`
function to `run-make-support`
rust-lang@a71c3ffce9 Auto merge of
rust-lang#125032 - compiler-errors:crash-dump-dir, r=onur-ozkan
rust-lang@0afd50e852 MIR operators:
clarify Shl/Shr handling of negative offsets
rust-lang@44fa5fd39a Auto merge of
rust-lang#125136 - matthiaskrgr:rollup-ljm15m3, r=matthiaskrgr
rust-lang@5f1a120ee5 Rollup merge of
rust-lang#125135 - chenyukang:yukang-fix-116502, r=compiler-errors
rust-lang@f7c2934420 Rollup merge of
rust-lang#125132 - mejrs:diag, r=compiler-errors
rust-lang@a8ff937b07 Rollup merge of
rust-lang#125108 - Zalathar:info-bitmap-bytes, r=nnethercote
rust-lang@03ff673dcc Rollup merge of
rust-lang#124990 - fmease:expand-weak-aliases-within-cts, r=compiler-errors
rust-lang@75895f59b0 Fix the dedup error
because of spans from suggestion
rust-lang@9e7aff7945 Auto merge of
rust-lang#125031 - Oneirical:dynamic-libs, r=jieyouxu
rust-lang@8994840f7e rustdoc: Negative
impls are not notable
rust-lang@91a3f04a3f fix the test
rust-lang@0160bff4b1 Auto merge of
rust-lang#125084 - Jules-Bertholet:fix-125058, r=Nadrieril
rust-lang@c30b41012d delegation:
Implement list delegation
rust-lang@18d7411719 Add
`on_unimplemented" typo suggestions
rust-lang@81f7e54962 Port issue-11908 to
rmake
rust-lang@1f61cc3078 port
no-cdylib-as-rdylib test
rust-lang@b1e5e5161a remove cxx_flags
rust-lang@1f5837ae25 rewrite
c-link-to-rust-staticlib
rust-lang@5cc020d3df avoid using
aligned_alloc; posix_memalign is better-behaved
rust-lang@c81be68fb4 coverage: Remove
confusing comments from `CoverageKind`
rust-lang@bfadc3a9b9 coverage:
`CoverageIdsInfo::mcdc_bitmap_bytes` is never needed
rust-lang@fe8f66e4bc `rustc_hir_typeck`:
Account for `skipped_ref_pats` in `expr_use_visitor`
rust-lang@4db00fe229 Use an helper to
move the files
rust-lang@7fde7308bf reverse condition in
`uN::checked_sub`
rust-lang@848f3c2c6e Make crashes dump
mir to build dir
rust-lang@35a5be2833 Also expand weak
alias tys inside consts inside `expand_weak_alias_tys`
rust-lang@4edf12d33e Improve escape
methods.
rust-lang@16981ba406 Avoid panicking
branch in `EscapeIterInner`.
rust-lang@e3fc97be2b Inline
`EscapeDebug::size_hint`.

Co-authored-by: celinval <[email protected]>
Co-authored-by: Zyad Hassan <[email protected]>
bors added a commit to rust-lang-ci/rust that referenced this pull request Jul 27, 2024
@bors
Auto merge of rust-lang#124905 - reitermarkus:u32-from-char-opt, r=sc…
3942254 
…ottmcm

Allow optimizing `u32::from::<char>`.

Extracted from rust-lang#124307.

This allows optimizing the panicking branch in the `escape_unicode` function, see https://rust.godbolt.org/z/61YhKrhvP.
github-actions bot pushed a commit to rust-lang/miri that referenced this pull request Jul 30, 2024
@bors
Auto merge of #124905 - reitermarkus:u32-from-char-opt, r=scottmcm
cf2d1a9 
Allow optimizing `u32::from::<char>`.

Extracted from rust-lang/rust#124307.

This allows optimizing the panicking branch in the `escape_unicode` function, see https://rust.godbolt.org/z/61YhKrhvP.
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