RFR: 8340212: -Xshare:off -XX:CompressedClassSpaceBaseAddress=0x40001000000 crashes on macos-aarch64 [v10]

[Coleen Phillimore]

On Mon, 9 Dec 2024 20:48:01 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> `base_address` here is not from user input. It is something produced by the JVM after validity checks. So if we have an error it, we JVM has done something wrong. I think a fatal() would be apropriate.
>> 
>> In contract, SharedBaseAddress can be specified by the user, and we usually do not use fatal() to report such errors.
>
> SharedBaseAddress comes through here also.  It was valid at one point but UseCompactObjectHeaders forces the shift to be 10 so on using the shared archive, it might not be correct.

I added a comment why the validity check in -Xshare:dump doesn't actually check this and doesn't really have the full reservation size so it can check it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21695#discussion_r1876887124