RFR: 8318682: SA decoding of scalar replaced objects is broken [v3]

[Andrey Turbanov]

On Mon, 15 Jan 2024 05:37:02 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.
>
> Tom Rodriguez has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Pass the proper options to the lingered app

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/CommandProcessor.java line 1662:

> 1660:                             }
> 1661:                             if (blob instanceof NMethod) {
> 1662:                                 NMethod nm = (NMethod)  blob;

Suggestion:

                                NMethod nm = (NMethod) blob;

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/code/NMethod.java line 286:

> 284:     for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {
> 285:       PCDesc pd = new PCDesc(p);
> 286:       if (pd.getPCOffset()  == -1) {

Suggestion:

      if (pd.getPCOffset() == -1) {

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PR Review Comment: https://git.openjdk.org/jdk/pull/17407#discussion_r1452005032
PR Review Comment: https://git.openjdk.org/jdk/pull/17407#discussion_r1452004835