rustc_span: Optimize syntax context updates in spans

[petrochenkov]

By updating inline contexts in place, without touching span interner, when possible.

[rustbot]

r? @jieyouxu

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[petrochenkov]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 05a4539 with merge dcefc53...

[bors]

☀️ Try build successful - checks-actions
Build commit: dcefc53 (dcefc53a1dd4bffbe21f41f1cd334d3770fa9783)

[rust-timer]

Finished benchmarking commit (dcefc53): comparison URL.

Overall result: ❌✅ regressions and improvements - 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.

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-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)	0.3%	[0.2%, 0.4%]	2
Improvements ✅ (primary)	-0.4%	[-1.8%, -0.2%]	77
Improvements ✅ (secondary)	-1.1%	[-9.2%, -0.2%]	31
All ❌✅ (primary)	-0.4%	[-1.8%, -0.2%]	77

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)	1.4%	[1.0%, 1.7%]	3
Regressions ❌ (secondary)	2.7%	[2.7%, 2.7%]	1
Improvements ✅ (primary)	-1.2%	[-1.5%, -0.9%]	4
Improvements ✅ (secondary)	-4.0%	[-4.0%, -4.0%]	1
All ❌✅ (primary)	-0.1%	[-1.5%, 1.7%]	7

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)	-2.1%	[-2.8%, -1.2%]	8
Improvements ✅ (secondary)	-2.3%	[-4.8%, -1.3%]	6
All ❌✅ (primary)	-2.1%	[-2.8%, -1.2%]	8

Binary size

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

Bootstrap: 673.271s -> 673.179s (-0.01%)
Artifact size: 315.86 MiB -> 315.78 MiB (-0.02%)

[jieyouxu]

A question regarding the significance of a u32::MAX SyntaxContext, but otherwise looks good to me.

[petrochenkov]

I still need to clean up the code and factor out the common part from inline_ctxt and update_ctxt, that's why it's waiting on author.

[petrochenkov]

I've found an issue - the old logic may turn a partially-interned format into an inline-parent format on ctxt update (when ctxt is updated to zero), but the new logic doesn't reproduce that behavior.
It's a bug an not just a missed optimization, because it may result in two different Spans referring to the same SpanData.

UPD: This issue is fixed in the last update.

[petrochenkov]

Blocked on #125829.
@rustbot blocked

[rust-log-analyzer]

The job aarch64-gnu failed! Check out the build log: (web) (plain)

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

[401/3315] Building CXX object lib/InterfaceStub/CMakeFiles/LLVMInterfaceStub.dir/IFSHandler.cpp.o
[402/3315] Building CXX object lib/InterfaceStub/CMakeFiles/LLVMInterfaceStub.dir/ELFObjHandler.cpp.o
[403/3315] Building CXX object lib/IR/CMakeFiles/LLVMCore.dir/Verifier.cpp.o

Session terminated, killing shell...::group::Clock drift check
  local time: Mon Jun 10 00:05:31 UTC 2024
##[error]The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.
##[endgroup]
[404/3315] Building CXX object lib/IRPrinter/CMakeFiles/LLVMIRPrinter.dir/IRPrintingPasses.cpp.o
[405/3315] Building CXX object lib/FuzzMutate/CMakeFiles/LLVMFuzzMutate.dir/RandomIRBuilder.cpp.o
[406/3315] Building CXX object lib/IRReader/CMakeFiles/LLVMIRReader.dir/IRReader.cpp.o

[petrochenkov]

@bors retry

[bors]

⌛ Testing commit d5dd2d8 with merge a316785...

[bors]

☀️ Test successful - checks-actions
Approved by: cjgillot
Pushing a316785 to master...

[rust-timer]

Finished benchmarking commit (a316785): comparison URL.

Overall result: ❌✅ regressions and improvements - 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)	0.5%	[0.2%, 0.6%]	6
Regressions ❌ (secondary)	0.7%	[0.4%, 1.0%]	10
Improvements ✅ (primary)	-0.4%	[-1.5%, -0.2%]	37
Improvements ✅ (secondary)	-1.5%	[-9.3%, -0.2%]	33
All ❌✅ (primary)	-0.3%	[-1.5%, 0.6%]	43

Max RSS (memory usage)

Results (primary -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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.7%	[-2.7%, -1.0%]	3
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.7%	[-2.7%, -1.0%]	3

Cycles

Results (primary -1.8%, secondary -4.9%)

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)	-1.8%	[-2.3%, -1.2%]	5
Improvements ✅ (secondary)	-4.9%	[-5.1%, -4.6%]	2
All ❌✅ (primary)	-1.8%	[-2.3%, -1.2%]	5

Binary size

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

Bootstrap: 672.142s -> 675.838s (0.55%)
Artifact size: 319.14 MiB -> 320.09 MiB (0.30%)

[Kobzol]

Nice win across the board, wins outweigh the losses.

@rustbot label: +perf-regression-triaged