Split out the various responsibilities of `rustc_metadata::Lazy` #97291

compiler-errors · 2022-05-22T21:00:44Z

Lazy<T> actually acts like three different types -- a pointer in the crate metadata to a single value, a pointer to a list/array of values, and an indexable pointer of a list of values (a table).

We currently overload Lazy<T> to work differently than Lazy<[T]> and the same for Lazy<Table<I, T>>. All is well with some helper adapter traits such as LazyQueryDecodable and EncodeContentsForLazy.

Well, changes in #97287 that make Lazy work with the now invariant lifetime 'tcx make these adapters fall apart because of coherence reasons. So we split out these three types and rework some of the helper traits so it's both 1. more clear to understand, and 2. compatible with the changes later in that PR.

Split out from #97287 so it can be reviewed separately, since this PR stands on its own.

rust-highfive · 2022-05-22T21:00:47Z

r? @wesleywiser

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compiler/rustc_metadata/src/rmeta/mod.rs

cjgillot · 2022-05-23T15:16:16Z

@bors try @rust-timer queue

rust-timer · 2022-05-23T15:16:18Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-05-23T15:16:25Z

⌛ Trying commit 30323cc40d0af9bd158a823d2a8818b26f8d269f with merge 48a331d69e217e5bec16e805669ffe759820ba8d...

bors · 2022-05-23T17:07:03Z

☀️ Try build successful - checks-actions
Build commit: 48a331d69e217e5bec16e805669ffe759820ba8d (48a331d69e217e5bec16e805669ffe759820ba8d)

rust-timer · 2022-05-23T17:07:05Z

Queued 48a331d69e217e5bec16e805669ffe759820ba8d with parent 32c8c5d, future comparison URL.

rust-timer · 2022-05-23T18:25:53Z

Finished benchmarking commit (48a331d69e217e5bec16e805669ffe759820ba8d): comparison url.

Instruction count

Primary benchmarks: 😿 relevant regressions found
Secondary benchmarks: mixed results

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	19	21	0	1	19
mean²	0.5%	1.1%	N/A	-0.3%	0.5%
max	1.6%	1.6%	N/A	-0.3%	1.6%

Max RSS (memory usage)

Results

Primary benchmarks: mixed results
Secondary benchmarks: mixed results

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	1	6	1	5	2
mean²	1.9%	1.4%	-1.0%	-1.5%	0.4%
max	1.9%	2.5%	-1.0%	-2.0%	1.9%

Cycles

Results

Primary benchmarks: no relevant changes found
Secondary benchmarks: 😿 relevant regressions found

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	0	7	0	0	0
mean²	N/A	2.0%	N/A	N/A	N/A
max	N/A	2.2%	N/A	N/A	N/A

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf +perf-regression

number of relevant changes ↩ ↩² ↩³
the arithmetic mean of the percent change ↩ ↩² ↩³

jackh726 · 2022-05-24T01:13:21Z

Slight regression, but I think it's mild enough. Combined with the clarity wins and unblocking of future work, I think we just land.

compiler-errors · 2022-05-24T01:16:33Z

I'm gonna try to slap some inline(always) onto the new query post-decode trait I introduced, but if that yields no benefit, then I'll chalk it up to noise.

compiler-errors · 2022-05-24T02:51:27Z

@bors try @rust-timer queue

rust-timer · 2022-05-24T02:51:28Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-05-24T02:51:34Z

⌛ Trying commit 2b5e592 with merge a9dc794e2e93c93fb228ae43a6ca17eb4192ff7d...

bors · 2022-05-24T04:26:57Z

☀️ Try build successful - checks-actions
Build commit: a9dc794e2e93c93fb228ae43a6ca17eb4192ff7d (a9dc794e2e93c93fb228ae43a6ca17eb4192ff7d)

rust-timer · 2022-05-24T04:26:59Z

Queued a9dc794e2e93c93fb228ae43a6ca17eb4192ff7d with parent ee160f2, future comparison URL.

rust-timer · 2022-05-24T05:45:13Z

Finished benchmarking commit (a9dc794e2e93c93fb228ae43a6ca17eb4192ff7d): comparison url.

Instruction count

Primary benchmarks: 🎉 relevant improvement found
Secondary benchmarks: mixed results

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	0	4	1	11	1
mean²	N/A	0.8%	-0.3%	-0.3%	-0.3%
max	N/A	1.0%	-0.3%	-0.3%	-0.3%

Max RSS (memory usage)

Results

Primary benchmarks: mixed results
Secondary benchmarks: mixed results

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	2	4	1	2	3
mean²	5.2%	2.1%	-3.3%	-1.8%	2.4%
max	7.1%	3.1%	-3.3%	-2.1%	7.1%

Cycles

Results

Primary benchmarks: mixed results
Secondary benchmarks: 🎉 relevant improvements found

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	8	0	6	7	14
mean²	3.2%	N/A	-1.8%	-2.1%	1.0%
max	7.1%	N/A	-2.6%	-3.1%	7.1%

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf -perf-regression

number of relevant changes ↩ ↩² ↩³
the arithmetic mean of the percent change ↩ ↩² ↩³

compiler-errors · 2022-05-24T05:48:40Z

Okay, well fixing the incorrect size_hint implementation and adding some inlines did the trick I guess.

cjgillot · 2022-05-24T10:52:39Z

@bors r+

bors · 2022-05-24T10:52:42Z

📌 Commit 2b5e592 has been approved by cjgillot

bors · 2022-05-24T13:42:36Z

⌛ Testing commit 2b5e592 with merge ee9726c...

bors · 2022-05-24T16:23:26Z

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing ee9726c to master...

rust-log-analyzer · 2022-05-24T18:10:30Z

The job x86_64-gnu-llvm-12 failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

...i....F.............................................i................................
Some tests failed in compiletest suite=mir-opt mode=mir-opt host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu
failures:

---- [mir-opt] src/test/mir-opt/inline/inline-generator.rs stdout ----
30 +         let mut _10: bool;               // in scope 6 at $DIR/inline-generator.rs:15:9: 15:9
31 +         let _11: bool;                   // in scope 6 at $DIR/inline-generator.rs:15:6: 15:7
32 +         let mut _12: u32;                // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
- +         let mut _13: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
- +         let mut _14: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
- +         let mut _15: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]; // in scope 6 at $DIR/inline-generator.rs:15:5: 15:41
37   
38       bb0: {


76 +         StorageLive(_10);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
77 +         StorageLive(_11);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
78 +         StorageLive(_12);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
- +         StorageLive(_13);                // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
- +         _13 = move (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]); // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
- +         _12 = discriminant((*_13));      // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
- +         StorageDead(_13);                // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
+ +         _12 = discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]))); // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
83 +         switchInt(move _12) -> [0_u32: bb3, 1_u32: bb8, 3_u32: bb7, otherwise: bb9]; // scope 6 at $DIR/inline-generator.rs:15:5: 15:41
85   


124 +         Deinit(_1);                      // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
125 +         ((_1 as Yielded).0: i32) = move _8; // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
126 +         discriminant(_1) = 0;            // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
- +         StorageLive(_14);                // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
- +         _14 = move (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]); // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
- +         discriminant((*_14)) = 3;        // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
- +         StorageDead(_14);                // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
+ +         discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]))) = 3; // scope 6 at $DIR/inline-generator.rs:15:11: 15:39
131 +         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:11: 15:39
133 + 


138 +         Deinit(_1);                      // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
139 +         ((_1 as Complete).0: bool) = move _10; // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
140 +         discriminant(_1) = 1;            // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
- +         StorageLive(_15);                // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
- +         _15 = move (_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]); // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
- +         discriminant((*_15)) = 1;        // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
- +         StorageDead(_15);                // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
+ +         discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41]))) = 1; // scope 6 at $DIR/inline-generator.rs:15:41: 15:41
145 +         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:41: 15:41
147 + 


thread '[mir-opt] src/test/mir-opt/inline/inline-generator.rs' panicked at 'Actual MIR output differs from expected MIR output /checkout/src/test/mir-opt/inline/inline_generator.main.Inline.diff', src/tools/compiletest/src/runtest.rs:3410:25


failures:
    [mir-opt] src/test/mir-opt/inline/inline-generator.rs

rust-timer · 2022-05-24T18:10:42Z

Finished benchmarking commit (ee9726c): comparison url.

Instruction count

Primary benchmarks: no relevant changes found
Secondary benchmarks: 😿 relevant regressions found

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	0	7	0	0	0
mean²	N/A	1.0%	N/A	N/A	N/A
max	N/A	1.1%	N/A	N/A	N/A

Max RSS (memory usage)

Results

Primary benchmarks: no relevant changes found
Secondary benchmarks: mixed results

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	0	3	0	1	0
mean²	N/A	1.6%	N/A	-1.5%	N/A
max	N/A	2.5%	N/A	-1.5%	N/A

Cycles

Results

Primary benchmarks: 🎉 relevant improvement found
Secondary benchmarks: 🎉 relevant improvement found

	Regressions 😿 (primary)	Regressions 😿 (secondary)	Improvements 🎉 (primary)	Improvements 🎉 (secondary)	All 😿 🎉 (primary)
count¹	0	0	1	1	1
mean²	N/A	N/A	-2.3%	-6.3%	-2.3%
max	N/A	N/A	-2.3%	-6.3%	-2.3%

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

number of relevant changes ↩ ↩² ↩³
the arithmetic mean of the percent change ↩ ↩² ↩³

rust-highfive assigned wesleywiser May 22, 2022

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label May 22, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 22, 2022

jackh726 reviewed May 22, 2022

View reviewed changes

compiler/rustc_metadata/src/rmeta/mod.rs Outdated Show resolved Hide resolved

compiler-errors force-pushed the lazy-is-actually-3-types-in-a-trenchcoat branch from 791765c to 30323cc Compare May 22, 2022 23:48

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label May 23, 2022

rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels May 23, 2022

compiler-errors added 3 commits May 23, 2022 19:39

split out the various responsibilities of Lazy

ca5e60b

refine comments, disambiguate len for array and tables

14e5816

Fix iterator implementation, add some inlines

2b5e592

compiler-errors force-pushed the lazy-is-actually-3-types-in-a-trenchcoat branch from 30323cc to 2b5e592 Compare May 24, 2022 02:50

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label May 24, 2022

rustbot removed S-waiting-on-perf Status: Waiting on a perf run to be completed. perf-regression Performance regression. labels May 24, 2022

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 24, 2022

bors added the merged-by-bors This PR was explicitly merged by bors. label May 24, 2022

bors merged commit ee9726c into rust-lang:master May 24, 2022

rustbot added this to the 1.63.0 milestone May 24, 2022

This was referenced May 24, 2022

Make lowering a query #95573

Merged

Implement pointee metadata unsizing via a TypedMetadata<T> container #97052

Closed

JohnTitor mentioned this pull request Jul 26, 2022

Fix some links rust-lang/rustc-dev-guide#1411

Merged

compiler-errors deleted the lazy-is-actually-3-types-in-a-trenchcoat branch August 11, 2023 20:06

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Split out the various responsibilities of `rustc_metadata::Lazy` #97291

Split out the various responsibilities of `rustc_metadata::Lazy` #97291

compiler-errors commented May 22, 2022

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compiler-errors commented May 24, 2022 •

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Split out the various responsibilities of rustc_metadata::Lazy #97291

Split out the various responsibilities of rustc_metadata::Lazy #97291

Conversation

compiler-errors commented May 22, 2022

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Footnotes

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Footnotes

Split out the various responsibilities of `rustc_metadata::Lazy` #97291

Split out the various responsibilities of `rustc_metadata::Lazy` #97291

compiler-errors commented May 24, 2022 •

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