Decouple SCC annotations from SCCs

[amandasystems]

This rewires SCC annotations to have them be a separate, visitor-type data structure. It was broken out of #130227, which needed them to be able to remove unused annotations after computation without recomputing the SCCs themselves.

As a drive-by it also removes some redundant code from the hot loop in SCC construction for a performance improvement.

r? lcnr

[lcnr]

@bors try @rust-timer queue

[bors]

⌛ Trying commit ae763d6 with merge 207b712...

[bors]

☀️ Try build successful - checks-actions
Build commit: 207b712 (207b712831b7b56fe9f65a990e17ad17f59246e1)

[rust-timer]

Finished benchmarking commit (207b712): comparison URL.

Overall result: ✅ improvements - no action needed

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-perf -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.2%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.7%, secondary -1.7%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.9%	[0.4%, 2.3%]	11
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.5%	[-0.6%, -0.4%]	2
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	0.7%	[-0.6%, 2.3%]	13

Cycles

Results (primary 0.5%, secondary 3.5%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.5%, 0.5%]	1
Regressions ❌ (secondary)	3.5%	[3.5%, 3.5%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.5%	[0.5%, 0.5%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 775.789s -> 774.37s (-0.18%)
Artifact size: 364.79 MiB -> 364.78 MiB (-0.00%)

[amandasystems]

@bors r=@lcnr

[bors]

@amandasystems: 🔑 Insufficient privileges: Not in reviewers

[amandasystems]

Oh, seems I misunderstood that piece of jargon then

[lcnr]

@bors r+

[bors]

📌 Commit b660ab9 has been approved by lcnr

It is now in the queue for this repository.

[bors]

⌛ Testing commit b660ab9 with merge 618d7a1...

[rust-log-analyzer]

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

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

error: test run failed!
status: exit status: 101
command: RUSTC="/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" RUST_TEST_THREADS="4" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/remote-test-client" "run" "0" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/coercion/coerce-reborrow-imm-ptr-arg/a"
--- stdout -------------------------------
uploaded "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/coercion/coerce-reborrow-imm-ptr-arg/a", waiting for result
------------------------------------------
--- stderr -------------------------------

thread 'main' panicked at src/tools/remote-test-client/src/main.rs:309:9:
client.read_exact(&mut header) failed with Connection reset by peer (os error 104)

[bors]

💔 Test failed - checks-actions

[amandasystems]

💔 Test failed - checks-actions

That seems very spurious to me

[tmiasko]

@bors retry #97669

[bors]

⌛ Testing commit b660ab9 with merge 3350c1eb3fd8fe1bee1ed4c76944d707bd256876...

[bors]

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 3350c1e to master...

[github-actions]

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 0e517d3 (parent) -> 3350c1e (this PR)

Test differences

Show 13 test diffs

Stage 1

• graph::scc::tests::test_simple_cycle_max: pass -> [missing] (J0)

Additionally, 12 doctest diffs were found. These are ignored, as they are noisy.

Job group index

• J0: aarch64-apple, aarch64-gnu, i686-gnu-2, i686-gnu-nopt-2, i686-msvc-2, x86_64-apple-1, x86_64-gnu, x86_64-gnu-llvm-19-3, x86_64-gnu-llvm-20-3, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-2, x86_64-msvc-2

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 3350c1eb3fd8fe1bee1ed4c76944d707bd256876 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

1. x86_64-apple-2: 6682.2s -> 5306.3s (-20.6%)
2. x86_64-apple-1: 9135.6s -> 10451.1s (14.4%)
3. dist-apple-various: 8195.5s -> 7142.7s (-12.8%)
4. dist-x86_64-apple: 7301.6s -> 8097.6s (10.9%)
5. dist-arm-linux: 4670.0s -> 5132.0s (9.9%)
6. i686-msvc-2: 7167.6s -> 7873.5s (9.8%)
7. dist-aarch64-apple: 5144.1s -> 4716.4s (-8.3%)
8. dist-x86_64-mingw: 7647.8s -> 8262.0s (8.0%)
9. i686-gnu-1: 8848.1s -> 8392.0s (-5.2%)
10. x86_64-gnu-tools: 5568.4s -> 5838.1s (4.8%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

[rust-timer]

Finished benchmarking commit (3350c1e): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.1%]	2
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.1%]	1
All ❌✅ (primary)	-0.1%	[-0.1%, -0.1%]	2

Max RSS (memory usage)

Results (primary 0.2%, secondary -1.1%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.7%	[0.4%, 2.9%]	25
Regressions ❌ (secondary)	2.6%	[2.3%, 3.0%]	2
Improvements ✅ (primary)	-1.1%	[-2.1%, -0.4%]	8
Improvements ✅ (secondary)	-2.9%	[-3.6%, -2.0%]	4
All ❌✅ (primary)	0.2%	[-2.1%, 2.9%]	33

Cycles

Results (primary -0.2%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.4%, 1.0%]	5
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-0.9%, -0.4%]	9
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.2%	[-0.9%, 1.0%]	14

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 768.358s -> 767.941s (-0.05%)
Artifact size: 365.48 MiB -> 365.55 MiB (0.02%)