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]

💥 Test timed out

[bors]

☔ The latest upstream changes (presumably #125989) made this pull request unmergeable. Please resolve the merge conflicts.

[jieyouxu]

This PR's associated CI runs are kinda cursed

[jieyouxu]

We could give it another try after fixing the merge conflict.
@rustbot author

[Oneirical]

@rustbot review

Conflict resolved, though, while running around and removing conflicts, I noticed that there used to be a silent fail here:

let llvm_bin_dir = env::var("LLVM_BIN_DIR");

This is really strange, since I would have expected this to cause a compilation error from the unexpected Result type then getting passed around.

This could explain why the test job is getting stuck. Maybe we'll get a different error message this time.

[Oneirical]

@bors try

[bors]

⌛ Trying commit fdd3967 with merge 30cb27a...

[bors]

💔 Test failed - checks-actions