[jdk21u-dev] RFR: 8328085: C2: Use after free in PhaseChaitin::Register_Allocate()

[Richard Reingruber]

On Tue, 10 Dec 2024 08:47:30 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> Hi all,
> 
> This pull request contains a backport of commit https://github.com/openjdk/jdk/commit/93aa7e2fcf87c4dc62de4ea71be543ee677b11be.
> 
> The commit being backported was authored by Richard Reingruber on 21 Nov 2024 and was reviewed by Tobias Hartmann and Martin Doerr.
> 
> The original commit did not apply because the `TracePhase` constructor used above the removed line was changed.
> EDIT: the bot considers the backport to be clean.
> // Actually I had to resolve the minimal conflict I mentioned above.
> 
> I'd consider the risk medium. There could be scenarios with higher memory usage in c2 register allocation.
> DaCapo tests didn't show higher memory usage.
> (the measuring code was part of the [original pull request](https://github.com/openjdk/jdk/pull/22200/commits))
> 
> 
> Max. ResourceArea size in KB after C2 PhaseChaitin::merge_multidefs
> 
> DaCapo Benchmark        Basline        Pull Request
> 
> avrora                     2167               2167
> batik                      2600               2509
> biojava                    3125               3125
> cassandra                   482                514
> eclipse                    3408               3400
> fop                        2863               2895
> graphchi                   1331               1331
> h2                         3204               3290
> h2o                         638                514
> jme                        2160               2160
> jython                     9617               9649
> kafka                      2577               2586
> luindex                    2738               2902
> lusearch                   2645               2645
> pmd                        2931               2723
> spring                     2958               3383
> sunflow                    1437               1437
> tomcat                     2668               2643
> tradebeans                 2975               2663
> tradesoap                  3124               2663
> xalan                      3025               2826
> zxing                      2473               2505
> 
> 
> The fix passed our CI testing: JTReg tests: tier1-4 of hotspot and jdk. All of Langtools and jaxp. JCK, SPECjvm2008, SPECjbb2015, Renaissance Suite, and SAP specific tests.
> Testing was done with fastdebug builds on the main platforms and also on Linux/PPC64le and AIX.
> 
> Thanks, Richard.

Retrying... /integrate

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PR Comment: https://git.openjdk.org/jdk21u-dev/pull/1217#issuecomment-2547755968