[lworld] Integrated: 8367548: compiler/intrinsics/bmi tests fail with -XX:+AOTClassLinking

[Christian Hagedorn]

On Fri, 12 Sep 2025 15:52:06 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> The `compiler/intrinsics/bmi` tests started to fail with new AOT changes merged in. 
> 
> ### AOT Warnings with Valhalla due to Adapter Hash Collision
> From the log messages, I saw that we have the following warning message printed with UL:
> 
> '[0.020s][warning][aot,codecache,stubs] Saved blob's name 'IIIIIIIL' is different from the expected name 'LIIIIIII'
> 
> This warning can be traced back to a collision in caching adapters with AOT where two adapters have the same hash. As a result, we need to drop one of the adapters in the AOT cache which is unfortunate but not a problem in correctness. This hash collision seems to be specific to Valhalla because we have a lot more adapters compared to mainline. There is currently an open RFE in mainline ([JDK-8364929](https://bugs.openjdk.org/browse/JDK-8364929)) which tries to improve the situation to give each adapters a unique id.
> 
> ###  Comparison of `Xint` and `Xcomp` Output Fails due to different Timestamps
> The `compiler/intrinsics/bmi` tests call `BMITestRunner` which will run the same test with `-Xint` and `-Xcomp` and then compare the output:
> https://github.com/openjdk/valhalla/blob/28b96c080081b8ebab2656d5dc0f904072d15e40/test/hotspot/jtreg/compiler/intrinsics/bmi/BMITestRunner.java#L87-L100
> We see the AOT warning actually in both runs. The comparison fails because we have a different timestamp in the log for `-Xint` and `-Xcomp`:
> 
> [0.020s][warning][aot,codecache,stubs] Saved blob's name 'IIIIIIIL' is different from the expected name 'LIIIIIII'
> [0.013s][warning][aot,codecache,stubs] Saved blob's name 'IIIIIIIL' is different from the expected name 'LIIIIIII'
> 
> So, the fix would be to get rid of the timestamps. 
> 
> ### Getting Rid of Timestamps already Implemented but Wrongly
> However, we already have some special code that actually wants to remove timestamps and all AOT logs altogether (introduced with https://github.com/openjdk/valhalla/commit/3b32f6a8ec37338764d3e6713247ff96e49bf5b3 for some Graal specific failure) :
> https://github.com/openjdk/valhalla/blob/28b96c080081b8ebab2656d5dc0f904072d15e40/test/hotspot/jtreg/compiler/intrinsics/bmi/BMITestRunner.java#L125-L129
> But this does not seem to work. I played around with `Xlog` and found that surprisingly this:
> 
> -Xlog:all=warning:stdout:level,tags -Xlog:aot=off
> 
> seems to be expanded to
> 
> -Xlog:all=warning:stdout:level,tags -Xlog:aot=off:stdout:<default decorators>
> 
> and the second `Xlog` overrides the decorators and reintroduces the timestamps again.
> 
> ### Proposed Fix
> The ...

This pull request has now been integrated.

Changeset: 1c011a37
Author:    Christian Hagedorn <chagedorn at openjdk.org>
URL:       https://git.openjdk.org/valhalla/commit/1c011a377002de35f8086a8ba4fdce1ed898cfca
Stats:     2 lines in 1 file changed: 0 ins; 1 del; 1 mod

8367548: compiler/intrinsics/bmi tests fail with -XX:+AOTClassLinking

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PR: https://git.openjdk.org/valhalla/pull/1582