Migrate run-make/pgo-branch-weights to rmake

[Oneirical]

Part of #121876 and the associated Google Summer of Code project.

This is a scary one and I expect things to break. Set as draft, because this isn't ready.

• There is this comment here, which suggests the test is excluded from the testing process due to a platform specific issue? I can't see anything here that would cause this test to not run...

// FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
// properly. Since we only have GCC on the CI ignore the test for now."

EDIT: This is specific to Windows-gnu.

• The Makefile has this line:

ifneq (,$(findstring x86,$(TARGET)))
COMMON_FLAGS=-Clink-args=-fuse-ld=gold

I honestly can't tell whether this is checking if the target IS x86, or IS NOT. EDIT: It's checking if it IS x86.

• I don't know why the Makefile was trying to pass an argument directly in the Makefile instead of setting that "aaaaaaaaaaaa2bbbbbbbbbbbb2bbbbbbbbbbbbbbbbcc" input as a variable in the Rust program directly. I changed that, let me know if that was wrong.

• Trying to rewrite cat "$(TMPDIR)/interesting.ll" | "$(LLVM_FILECHECK)" filecheck-patterns.txt resulted in some butchery. For starters, in tools.mk, LLVM_FILECHECK corrects its own backslashes on Windows distributions, but there is no further mention of it, so I assume this is a preset environment variable... but is it really? Then, the command itself uses a Standard Input and a passed input file as an argument simultaneously, according to the documentation.

try-job: aarch64-gnu

[rustbot]

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[lqd]

1. There is this comment here, which suggests the test is excluded from the testing process due to a platform specific issue? I can't see anything here that would cause this test to not run...

// FIXME(mati865): MinGW GCC miscompiles compiler-rt profiling library but with Clang it works
// properly. Since we only have GCC on the CI ignore the test for now."

it's the # ignore-windows-gnu in the makefile, which is where this mingw gcc bug is expected to happen, according to the comment

[jieyouxu]

Yeah, run-make Makefiles have # <directive-name> directives. What's funny about them like the old-format // <directive-name> directive in Rust code is that you can sneak in a directive in a comment block, e.g.

# This is a comment block that has a starting line,
# ignore-windows in the middle of the sentence,
# and hello world in the end of the sentence.

Here # ignore-windows is a (Makefile) directive.

[Oneirical]

Ah, I was wondering if that comment meant the test did not run at all... I am equally soothed that my work on this one was not wasted, and worried that this means it will have to be fully understood to proceed...

It does use features found in other tests, though, so this should make the other tests using LLVM instrumentation much easier to port.

EDIT: That does mean that the LLVM_FILECHECK part that fixes Windows path to use slashes won't have to be ported over in this test, since Windows is already getting ignored. Not sure if that mattered in the first place.

EDIT 2: Not Windows, Windows-gnu.

[lqd]

since Windows is already getting ignored

To clarify, windows-gnu is ignored, not windows-msvc (the main windows target), or the other windows targets.

[jieyouxu]

I'll take a closer took tomorrow

[jieyouxu]

Feel free to ping me if you need any PR CI runs (i.e. try jobs) for various platforms.

[Oneirical]

Feel free to ping me if you need any PR CI runs (i.e. try jobs) for various platforms.

@jieyouxu I might need some try jobs for windows-gnu (once CI is green). The description has been changed already.

[bors]

☔ The latest upstream changes (presumably #125752) made this pull request unmergeable. Please resolve the merge conflicts.

[bors]

💔 Test failed - checks-actions

[Oneirical]

@bors try

[bors]

🔒 Merge conflict

This pull request and the master branch diverged in a way that cannot be automatically merged. Please rebase on top of the latest master branch, and let the reviewer approve again.

How do I rebase?

Assuming self is your fork and upstream is this repository, you can resolve the conflict following these steps:

1. git checkout pgo-branch-weights (switch to your branch)
2. git fetch upstream master (retrieve the latest master)
3. git rebase upstream/master -p (rebase on top of it)
4. Follow the on-screen instruction to resolve conflicts (check git status if you got lost).
5. git push self pgo-branch-weights --force-with-lease (update this PR)

You may also read Git Rebasing to Resolve Conflicts by Drew Blessing for a short tutorial.

Please avoid the "Resolve conflicts" button on GitHub. It uses git merge instead of git rebase which makes the PR commit history more difficult to read.

Sometimes step 4 will complete without asking for resolution. This is usually due to difference between how Cargo.lock conflict is handled during merge and rebase. This is normal, and you should still perform step 5 to update this PR.

Error message

Removing tests/run-make/pgo-branch-weights/Makefile
Auto-merging src/tools/tidy/src/allowed_run_make_makefiles.txt
Auto-merging src/tools/run-make-support/src/lib.rs
CONFLICT (content): Merge conflict in src/tools/run-make-support/src/lib.rs
Automatic merge failed; fix conflicts and then commit the result.

[Oneirical]

@bors try

[bors]

⌛ Trying commit 0bb84af with merge 55dde6a...

[bors]

☀️ Try build successful - checks-actions
Build commit: 55dde6a (55dde6a6ff40e83623f3ce7ae7f38dc65332cb17)

[jieyouxu]

Left some minor nits, but otherwise looks good

[Oneirical]

Changes implemented. I'm slightly worried that the bors try success was not real and was caused by the CI outage of yesterday, but I suppose we're about to find out.

[jieyouxu]

We'll see in full CI.
@bors rollup=iffy

[jieyouxu]

@bors delegate+ (r=me after CI is green)

[bors]

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

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

[Oneirical]

@bors r=@jieyouxu

[bors]

📌 Commit 17b0771 has been approved by jieyouxu

It is now in the queue for this repository.

[bors]

⌛ Testing commit 17b0771 with merge f6b4b71...

[bors]

☀️ Test successful - checks-actions
Approved by: jieyouxu
Pushing f6b4b71 to master...

[rust-timer]

Finished benchmarking commit (f6b4b71): 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 1.9%)

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)	3.2%	[2.3%, 4.7%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.3%	[-2.3%, -2.3%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.9%	[-2.3%, 4.7%]	4

Cycles

Results (secondary -2.1%)

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)	-	-	0
Improvements ✅ (secondary)	-2.1%	[-2.1%, -2.1%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 672.648s -> 671.891s (-0.11%)
Artifact size: 320.29 MiB -> 320.29 MiB (0.00%)