Remove `InternedString` by nnethercote · Pull Request #65657 · rust-lang/rust

nnethercote · 2019-10-21T09:52:02Z

This PR removes InternedString by converting all occurrences to Symbol. There are a handful of places that need to use the symbol chars instead of the symbol index, e.g. for stable sorting; local conversions LocalInternedString is used in those places.

r? @eddyb

This avoids the needs for various conversions, and makes the code slightly faster, because `Symbol` comparisons and hashing is faster.

It's a full conversion, except in `DefKey::compute_stable_hash()` where a `Symbol` now is converted to an `InternedString` before being hashed. This was necessary to avoid test failures.

This requires changing the `PartialOrd`/`Ord` implementations to look at the chars rather than the symbol index.

This is a straightforward replacement except for two places where we have to convert to `LocalInternedString` to get a stable sort.

By using `LocalInternedString` instead for the few remaining uses.

eddyb · 2019-10-21T10:06:46Z

@bors try (for perf)

bors · 2019-10-21T10:06:57Z

⌛ Trying commit 08e2f05 with merge c7f7350...

@eddyb

Remove `InternedString` This PR removes `InternedString` by converting all occurrences to `Symbol`. There are a handful of places that need to use the symbol chars instead of the symbol index, e.g. for stable sorting; local conversions `LocalInternedString` is used in those places. r? @eddyb

eddyb · 2019-10-21T10:09:48Z

Oh, btw, I think LocalInternedString would make more sense if it was called SymbolContents.

nnethercote · 2019-10-21T10:39:07Z

Oh, btw, I think LocalInternedString would make more sense if it was called SymbolContents.

I agree! I was planning to rename in a follow-up. I had thought of SymbolChars but SymbolContents is also good.

nnethercote · 2019-10-21T10:40:52Z

BTW, you can now do !bors try !rust-timer queue (but with @ instead of !) to queue a try run and a perf run in one command.

bors · 2019-10-21T12:49:40Z

☀️ Try build successful - checks-azure
Build commit: c7f7350 (c7f73500c3bcd5b6268b7c1ed4b14d78ee82ce59)

eddyb · 2019-10-21T15:47:25Z

@rust-timer queue

rust-timer · 2019-10-21T15:47:26Z

Awaiting bors try build completion

Mark-Simulacrum · 2019-10-21T16:03:06Z

Queue needs to be run before the try build completes; @rust-timer build c7f7350

rust-timer · 2019-10-21T16:03:07Z

Queued c7f7350 with parent 1ba7b4e, future comparison URL.

rust-timer · 2019-10-21T23:13:35Z

Finished benchmarking try commit c7f7350, comparison URL.

nnethercote · 2019-10-22T02:42:25Z

Instruction counts look good, lots of small reductions of up to 1%. That's not surprising; hashing and ordering the symbol index is clearly cheaper than the symbol chars (which also involve a TLS lookup).

michaelwoerister · 2019-10-22T07:31:35Z

Just to be sure: Hash and Eq are still based on the same data for each type? If the two disagree it can lead to subtle, hard to detect bugs.

nnethercote · 2019-10-22T08:37:07Z

Just to be sure: Hash and Eq are still based on the same data for each type? If the two disagree it can lead to subtle, hard to detect bugs.

For Symbol both Hash and Eq are derived, and therefore both work with the index. And LocalInternedString doesn't implement Hash. So everything should be fine.

michaelwoerister · 2019-10-22T09:30:00Z

Great! Thanks for confirming, @nnethercote.

nnethercote · 2019-10-22T21:51:33Z

@eddyb gave me r+ on Discord.

@bors r=eddyb

bors · 2019-10-22T21:51:34Z

📌 Commit 08e2f05 has been approved by eddyb

bors · 2019-10-22T21:51:34Z

🌲 The tree is currently closed for pull requests below priority 1000, this pull request will be tested once the tree is reopened

@eddyb

…rly, r=eddyb Remove `InternedString` This PR removes `InternedString` by converting all occurrences to `Symbol`. There are a handful of places that need to use the symbol chars instead of the symbol index, e.g. for stable sorting; local conversions `LocalInternedString` is used in those places. r? @eddyb

@eddyb

…rly, r=eddyb Remove `InternedString` This PR removes `InternedString` by converting all occurrences to `Symbol`. There are a handful of places that need to use the symbol chars instead of the symbol index, e.g. for stable sorting; local conversions `LocalInternedString` is used in those places. r? @eddyb

@ghost

Rollup of 12 pull requests Successful merges: - #64178 (More Clippy fixes for alloc, core and std) - #65144 (Add Cow::is_borrowed and Cow::is_owned) - #65193 (Lockless LintStore) - #65479 (Add the `matches!( $expr, $pat ) -> bool` macro) - #65518 (Avoid ICE when checking `Destination` of `break` inside a closure) - #65583 (rustc_metadata: use a table for super_predicates, fn_sig, impl_trait_ref.) - #65641 (Derive `Rustc{En,De}codable` for `TokenStream`.) - #65648 (Eliminate `intersect_opt`.) - #65657 (Remove `InternedString`) - #65691 (Update E0659 error code long explanation to 2018 edition) - #65696 (Fix an issue with const inference variables sticking around under Chalk + NLL) - #65704 (relax ExactSizeIterator bound on write_bytes) Failed merges: r? @ghost

nnethercote added 7 commits October 21, 2019 11:31

Convert some InternedStrings to Symbols.
02edd14
This avoids the needs for various conversions, and makes the code slightly faster, because `Symbol` comparisons and hashing is faster.

Convert InternedStrings to Symbols in UnsafetyViolation.
c325553

Remove unnecessary impl Clean<String> for InternedString.
78c3427

Convert fields within DefPathData from InternedString to Symbol.
b8214e9
It's a full conversion, except in `DefKey::compute_stable_hash()` where a `Symbol` now is converted to an `InternedString` before being hashed. This was necessary to avoid test failures.

Change SymbolName::name from InternedString to Symbol.
dddacf1
This requires changing the `PartialOrd`/`Ord` implementations to look at the chars rather than the symbol index.

Use Symbol for codegen unit names.
2da7a9c
This is a straightforward replacement except for two places where we have to convert to `LocalInternedString` to get a stable sort.

Remove InternedString.
08e2f05
By using `LocalInternedString` instead for the few remaining uses.

rust-highfive assigned eddyb Oct 21, 2019

eddyb reviewed Oct 21, 2019
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Comment threadsrc/librustc/hir/map/definitions.rs

eddyb approved these changes Oct 21, 2019
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Centril added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 21, 2019

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nnethercote mentioned this pull request Oct 21, 2019
Streamline Symbol, InternedString, and LocalInternedString. #60869
Closed

petrochenkov assigned petrochenkov and unassigned petrochenkov Oct 21, 2019

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 Oct 22, 2019

Centril mentioned this pull request Oct 23, 2019
Rollup of 9 pull requests #65723
Closed

Centril mentioned this pull request Oct 23, 2019
Rollup of 12 pull requests #65733
Merged

bors merged commit 08e2f05 into rust-lang:masterOct 24, 2019

flip1995 added a commit to Mark-Simulacrum/rust-clippy that referenced this pull request Oct 24, 2019
Rustup torust-lang/rust#65657
5f4b5b9

nnethercote deleted the rm-InternedString-properly branch October 24, 2019 20:23

nnethercote mentioned this pull request Oct 27, 2019
[DO NOT MERGE] Remove InternedString#65543
Closed

ecstatic-morse mentioned this pull request Aug 6, 2020
Change the type of AssertModuleSource::available_cgus. #75210
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