Make region_scope_tree a tcx method

[zetanumbers]

Continuing on #154304.

Currently region_scope_tree query itself calls tcx.region_scope_tree(tcx.typeck_root_def_id(key)) if its key isn't a type-check root. I thought this might be an overhead and made region_scope_tree a tcx method which calls region_scope_tree_root query instead.

[rustbot]

r? @JohnTitor

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[zetanumbers]

r? @petrochenkov

Please run perf, I expect some improvements.

[petrochenkov]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 5326cba (5326cba370d7cbf51afd8ae9e33a1ee1a3d58732, parent: e3691a5bd58e92999bcbffedf640ecd61e02c29e)

[rust-timer]

Finished benchmarking commit (5326cba): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.4%, -0.2%]	4
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.2%]	1
All ❌✅ (primary)	-0.3%	[-0.4%, -0.2%]	4

Max RSS (memory usage)

Results (primary -0.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.9%	[2.9%, 2.9%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.3%	[-3.3%, -3.3%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.2%	[-3.3%, 2.9%]	2

Cycles

Results (secondary -1.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.5%	[-4.5%, -4.5%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 483.294s -> 491.715s (1.74%)
Artifact size: 395.05 MiB -> 395.04 MiB (-0.00%)

[petrochenkov]

Not as wide effect as #154304, but a good optimization for serde_derive specifically.
@bors r+ rollup=maybe

[rust-bors]

📌 Commit eb29fd7 has been approved by petrochenkov

It is now in the queue for this repository.

[zetanumbers]

Not as wide effect as #154304, but a good optimization for serde_derive specifically. bors r+ rollup=maybe

Actually serde_derive only benefits for incremental scenarios, which rarely not happen in practice since crate dependencies are built non-incrementally either way. I think maybe we shouldn't merge this.

[rust-bors]

☔ The latest upstream changes (presumably #154466) made this pull request unmergeable. Please resolve the merge conflicts.

This pull request was unapproved.

[camsteffen]

I would call it directly in cases where the caller already has a typeck root.