RFR: 8303002: Reject packed structs from linker [v2]

[Jorn Vernee]

On Tue, 28 Mar 2023 17:59:33 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> This patch adds checks in AbstractLinker to reject packed structs and structs with excess padding (e.g. unnamed bitfields), since both of those are currently not supported, and the ABI/spec seems too vague to base support on.
>
> Jorn Vernee has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase.

Added the missing javadoc and also fixed an issue I found where the current check was not catching excess trailing padding that still resulted in the size of a group being a multiple of its alignment constraint (added a test case for that as well)

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PR Comment: https://git.openjdk.org/jdk/pull/13164#issuecomment-1487742616