RFR: 8313800: AArch64: SA stack walking code having trouble finding sender frame when invoking LambdaForms is involved [v2]

[Chris Plummer]

On Fri, 8 Sep 2023 12:34:39 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> This PR fixes a specific problem caused by using r29/rfp to unwind Java code. For some time we have treated r29 as a callee-saved scratch register, and it is freely used by C2-generated code. Therefore, any code in SA that uses getFP() in a compiled frame is very likely to come to grief.
>> 
>> I believe this is the root cause of 8313800, but it's very hard to prove that because because it's something of an intermittent fault.
>
> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Duplicated comment

Marked as reviewed by cjplummer (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/15624#pullrequestreview-1620709638