automate offload, part 2 - clang calls

[ZuseZ4]

This automates steps 2+3 (the clang invocations) of the rust offload usage pipeline.
Now all that remains is a clang-linker-invocation after this step.

r? oli-obk

[rustbot]

Requested reviewer is already assigned to this pull request.

Please choose another assignee.

[bors]

☔ The latest upstream changes (presumably #150177) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[oli-obk]

@bors r+ rollup

[bors]

📌 Commit 8e1d803 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8e1d803 with merge 99ff3fb...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 99ff3fb to main...

[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 0bd13c3 (parent) -> 99ff3fb (this PR)

Test differences

Show 3 test diffs

3 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 99ff3fbb86658b427f5dd7daaae8db5626a63c26 --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. dist-aarch64-llvm-mingw: 6665.3s -> 5504.0s (-17.4%)
2. dist-aarch64-apple: 6903.4s -> 8039.4s (+16.5%)
3. dist-x86_64-apple: 6741.9s -> 7805.0s (+15.8%)
4. x86_64-gnu-debug: 7466.5s -> 6598.3s (-11.6%)
5. dist-various-1: 4555.7s -> 4033.5s (-11.5%)
6. dist-aarch64-msvc: 5944.1s -> 5327.8s (-10.4%)
7. aarch64-msvc-2: 5862.8s -> 6336.3s (+8.1%)
8. x86_64-msvc-2: 8656.4s -> 8021.6s (-7.3%)
9. dist-sparcv9-solaris: 5178.1s -> 4817.2s (-7.0%)
10. aarch64-gnu-llvm-20-2: 3040.6s -> 3232.8s (+6.3%)

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 (99ff3fb): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results (primary -3.7%)

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)	-3.7%	[-3.7%, -3.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.7%	[-3.7%, -3.7%]	1

Cycles

Results (secondary 4.1%)

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)	4.1%	[4.1%, 4.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 481.073s -> 482.582s (0.31%)
Artifact size: 390.31 MiB -> 390.35 MiB (0.01%)