RFR: 8318682: SA decoding of scalar replaced objects is broken

[Vladimir Kozlov]

On Fri, 12 Jan 2024 21:26:36 GMT, Tom Rodriguez <never at openjdk.org> wrote:

> The changes for JDK-8287061 didn't update the SA decoding logic and there are other places where the decoding has gotten out of sync with HotSpot.  Some of them can't be tested because they are part of JVMCI but I've added a directed test for the JDK-8287061 code and a more brute force test that tries to decode everything.

Thank you, Tom, for updating SA for new EA code.

test/hotspot/jtreg/serviceability/sa/ClhsdbTestAllocationMerge.java line 36:

> 34:  * @requires vm.hasSA
> 35:  * @library /test/lib
> 36:  * @run main/othervm -XX:CompileThresholdScaling=0.01 -XX:CompileCommand=compileonly,compiler.c2.HeapDumper::testIt -XX:CompileCommand=exclude,compiler.c2.HeapDumper::dummy ClhsdbTestAllocationMerge

`LingeredAppWithAllocationMerge` instead of `compiler.c2.HeapDumper`

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PR Review: https://git.openjdk.org/jdk/pull/17407#pullrequestreview-1819108372
PR Review Comment: https://git.openjdk.org/jdk/pull/17407#discussion_r1450953352