RFR: 8344168: Change Unsafe base offset from int to long

[ExE Boss]

On Thu, 14 Nov 2024 23:20:23 GMT, Dean Long <dlong at openjdk.org> wrote:

>> The type of the Unsafe base offset constant is int, which may cause overflow when adding int offsets, such as 8343925 (PR #22012). 8343984 (PR #22027) fixes most of the offset overflows in JDK, but ArraysSupport and CRC32C are still unfixed.
>> 
>> @liach proposed the idea of ​​changing the Unsafe base offset to long, which is a complete solution to the Unsafe offset overflow. After discussing with @liach, I submitted this PR to implement @liach's idea.
>
> Doesn't this break any apps that use these offsets?  Aren't these fields part of the public API of Unsafe, so changing them requires a CSR?

@dean-long
> Doesn't this break any apps that use these offsets? Aren't these fields part of the public API of Unsafe, so changing them requires a CSR?

This is the encapsulated JDK‑internal `Unsafe` in `java.base`, not the legacy `sun.misc.Unsafe`.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/22095#issuecomment-2477742637