Revert "Update cc-rs to 1.2.39 #146186"

[jieyouxu]

This reverts #146186. This will mean regressing whichever cc fixes were needed for

fixes when compiling the Rust compiler for Arm64EC.

It's not clear which cc change causes the across-the-board perf regression, I suspect it's a change in how certain compiler flags are handed. But I can immediately tell this is a rabbit hole to investigate, so let's revert for now to return-to-baseline and alleviate time pressure.

[rustbot]

These commits modify the Cargo.lock file. Unintentional changes to Cargo.lock can be introduced when switching branches and rebasing PRs.

If this was unintentional then you should revert the changes before this PR is merged.
Otherwise, you can ignore this comment.

[rustbot]

⚠️ Warning ⚠️

• There are issue links (such as #123) in the commit messages of the following commits.
  Please move them to the PR description, to avoid spamming the issues with references to the commit, and so this bot can automatically canonicalize them to avoid issues with subtree.
  • 2b9b7bb

[jieyouxu]

@bors try @rust-timer queue

[jieyouxu]

@rustbot reroll

[madsmtm]

r? me

Looks good, feel free to r=me once perf finishes.

@bors rollup=never delegate+

⚠️ Warning ⚠️

* There are issue links (such as `#123`) in the commit messages of the following commits.
  _Please move them to the PR description, to avoid spamming the issues with references to the commit, and so this bot can automatically canonicalize them to avoid issues with subtree._
  
  * [2b9b7bb](https://github.com/rust-lang/rust/commit/2b9b7bb3d4d55a7823e900e031324fcd57da9c92)

Also note this.

[bors]

✌️ @jieyouxu, you can now approve this pull request!

If @madsmtm told you to "r=me" after making some further change, please make that change, then do @bors r=@madsmtm

[rust-bors]

☀️ Try build successful (CI)
Build commit: 6fe122f (6fe122feddb1c4e81559df84ed0e5f2a2bf962ef, parent: 6906167e01fba6f702f123264653f8e401546731)

[rust-timer]

Finished benchmarking commit (6fe122f): 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)	-0.7%	[-3.6%, -0.3%]	258
Improvements ✅ (secondary)	-0.9%	[-2.9%, -0.0%]	286
All ❌✅ (primary)	-0.7%	[-3.6%, -0.3%]	258

Max RSS (memory usage)

Results (primary -3.5%)

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)	-	-	0
Improvements ✅ (primary)	-3.5%	[-3.5%, -3.5%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.5%	[-3.5%, -3.5%]	1

Cycles

Results (primary -3.2%, secondary -3.2%)

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)	-	-	0
Improvements ✅ (primary)	-3.2%	[-4.3%, -2.5%]	3
Improvements ✅ (secondary)	-3.2%	[-3.2%, -3.2%]	1
All ❌✅ (primary)	-3.2%	[-4.3%, -2.5%]	3

Binary size

Results (primary -1.1%, secondary 0.0%)

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)	0.0%	[0.0%, 0.0%]	1
Improvements ✅ (primary)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.1%	[-1.1%, -1.1%]	1

Bootstrap: 475.565s -> 473.414s (-0.45%)
Artifact size: 390.38 MiB -> 390.86 MiB (0.12%)

[mati865]

@bors r=@madsmtm

[bors]

📌 Commit 2b9b7bb has been approved by madsmtm

It is now in the queue for this repository.

[bors]

⌛ Testing commit 2b9b7bb with merge ab4960e...

[bors]

☀️ Test successful - checks-actions
Approved by: madsmtm
Pushing ab4960e to master...

[github-actions]

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing d5419f1 (parent) -> ab4960e (this PR)

Test differences

No test diffs found

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard ab4960e680b07600ec90a8736f936df371bc7cf3 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

1. pr-check-1: 1459.2s -> 1946.0s (+33.4%)
2. x86_64-gnu-stable: 6537.9s -> 7788.3s (+19.1%)
3. x86_64-gnu-llvm-20-1: 3181.3s -> 3748.3s (+17.8%)
4. aarch64-gnu-llvm-20-2: 2266.4s -> 2660.4s (+17.4%)
5. dist-aarch64-apple: 8263.2s -> 6830.4s (-17.3%)
6. dist-apple-various: 3480.5s -> 4081.7s (+17.3%)
7. x86_64-rust-for-linux: 2606.9s -> 3027.1s (+16.1%)
8. aarch64-msvc-2: 4608.1s -> 5329.1s (+15.6%)
9. x86_64-gnu-gcc: 3015.2s -> 3478.1s (+15.4%)
10. i686-gnu-2: 5563.2s -> 6395.9s (+15.0%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

[rust-timer]

Finished benchmarking commit (ab4960e): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -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)	-0.7%	[-3.6%, -0.3%]	251
Improvements ✅ (secondary)	-0.9%	[-2.9%, -0.0%]	288
All ❌✅ (primary)	-0.7%	[-3.6%, -0.3%]	251

Max RSS (memory usage)

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

Cycles

Results (secondary -2.4%)

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)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 473.872s -> 473.772s (-0.02%)
Artifact size: 390.40 MiB -> 390.88 MiB (0.12%)