rustc_span: Optimize syntax context comparisons

[petrochenkov]

Including comparisons with root context.

• eq_ctxt doesn't require retrieving full SpanData, or taking the span interner lock twice.
• Checking SyntaxContext for "rootness" is cheaper than extracting a full outer ExpnData for it and checking it for rootness.

The internal lint for eq_ctxt is also tweaked to detect a.ctxt() != b.ctxt() in addition to a.ctxt() == b.ctxt().

[rustbot]

r? @TaKO8Ki

(rustbot has picked a reviewer for you, use r? to override)

[petrochenkov]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 7db910c with merge 5adf01d...

[bors]

☀️ Try build successful - checks-actions
Build commit: 5adf01d (5adf01dde4bb9a30a7fb49224735fb7267260b4a)

[rust-timer]

Finished benchmarking commit (5adf01d): 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 a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-0.8%, -0.4%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.7%	[-0.8%, -0.4%]	5

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)	2.5%	[2.5%, 2.5%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.1%	[-2.1%, -2.1%]	1
All ❌✅ (primary)	2.5%	[2.5%, 2.5%]	1

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.5%	[-1.5%, -1.5%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 666.95s -> 668.373s (0.21%)
Artifact size: 311.74 MiB -> 311.75 MiB (0.00%)

[TaKO8Ki]

@rustbot author

[rustbot]

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

[petrochenkov]

Apparently this machinery is typically used from diagnostics, so there's not much difference.
@rustbot ready

[cjgillot]

@bors r+

[bors]

📌 Commit 1945792 has been approved by cjgillot

It is now in the queue for this repository.

[petrochenkov]

@bors r=cjgillot

[bors]

📌 Commit 90d11d6 has been approved by cjgillot

It is now in the queue for this repository.

[bors]

⌛ Testing commit 90d11d6 with merge 9212108...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing 9212108 to master...

[rust-timer]

Finished benchmarking commit (9212108): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-0.8%, -0.4%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.6%	[-0.8%, -0.4%]	5

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)	5.8%	[2.2%, 10.7%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.9%	[-3.7%, -2.0%]	2
All ❌✅ (primary)	-	-	0

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)	6.6%	[5.8%, 7.4%]	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: 665.507s -> 668.835s (0.50%)
Artifact size: 308.52 MiB -> 308.53 MiB (0.01%)