Lock stderr in panic handler

[Zoxc]

Fixes #119789.

[rustbot]

r? @Nadrieril

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[Nadrieril]

Is there a risk of deadlock with this? Because of another part of the compiler taking the lock, or a double-panic maybe?

[Nadrieril]

I don't know enough about parallel trickery to approve this

r? compiler

[Zoxc]

It uses a re-entrant lock, so that should avoid issues happening on the same thread.

There's some risk of deadlock due to usages of queries sneaking in, but those already carry a deadlock risk due to using the query system in an invalid state.

[michaelwoerister]

Let's give it a try. It's easy enough to revert if the approach causes trouble.

@bors r+ rollup=never

[bors]

📌 Commit 288380d has been approved by michaelwoerister

It is now in the queue for this repository.

[bors]

⌛ Testing commit 288380d with merge 7de1a1f...

[bors]

☀️ Test successful - checks-actions
Approved by: michaelwoerister
Pushing 7de1a1f to master...

[rust-timer]

Finished benchmarking commit (7de1a1f): 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
Improvements ✅ (secondary)	-2.1%	[-2.1%, -2.1%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

Cycles

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

Binary size

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

Bootstrap: 674.911s -> 672.776s (-0.32%)
Artifact size: 310.31 MiB -> 310.29 MiB (-0.00%)