increase the accuracy of effective visibilities calculation

[Bryanskiy]

Effective visibilities are calculated lazily due to performance restrictions. Therefore

• crate should be walked at least 1 time in compute_effective_visibilities pass
• Impl's should always be in the effective visibilities table

to ensure that the table is filled in correctly.

r? @petrochenkov

[petrochenkov]

@bors r+

[bors]

📌 Commit 5e917a6 has been approved by petrochenkov

It is now in the queue for this repository.

[bors]

⌛ Testing commit 5e917a6 with merge 2961177...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing 2961177 to master...

[rust-timer]

Finished benchmarking commit (2961177): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.4%	[0.2%, 0.6%]	10
Regressions ❌ (secondary)	1.2%	[0.6%, 1.9%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[0.2%, 0.6%]	10

Max RSS (memory usage)

Results

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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.5%	[-3.8%, -0.5%]	6
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.5%	[-3.8%, -0.5%]	6

Cycles

Results

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
Regressions ❌ (secondary)	1.7%	[1.6%, 1.8%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 649.217s -> 648.751s (-0.07%)

[pnkfelix]

• primary regressions are to serde (check, debug, opt) and also cargo + webrender (both check)
• This PR added some extra work to the compiler to ensure some lazily-filled in tables are constructed correctly.
• Therefore, this seems like extra work that is largely unavoidable.
• marking as triaged.

@rustbot label: +perf-regression-triaged