RFR: 8271471: [IR Framework] Rare occurrence of "<!-- safepoint while printing -->" in PrintIdeal/PrintOptoAssembly can let tests fail

[Tobias Hartmann]

On Thu, 29 Jul 2021 12:25:27 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> A test VM used by the IR framework sometimes prints `` in the middle of emitting a `PrintIdeal` or `PrintOptoAssembly` output which could lead to IR matching failures:
> https://github.com/openjdk/jdk/blob/489e5fd12a37a45f4f5ea64b05f85c6f99f70811/src/hotspot/share/utilities/ostream.cpp#L918-L927
> 
> I thought about just bailing out of IR matching if this string is found after a failure but this issue also affects internal framework tests (I observed one case locally where this happened in the test `TestIRMatching`, letting it fail).
> 
> Handling `` makes things more complicated for the IR framework tests. I'm not sure about the value of printing this message in the first place. But if nobody objects, I suggest to either remove it or at least guard it with `Verbose`, for example. I went with the latter solution in this PR.
> 
> Thanks,
> Christian

I would also go with option 1). For the framework internal tests that expect and exception, couldn't you simply add something like a `hitSafepointWhilePrinting()` method to `IRViolationException` that you can use to check if verification of the exception should be skipped?

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PR: https://git.openjdk.java.net/jdk/pull/4932