RFR: 8303002: Reject packed structs from linker [v5]

[Maurizio Cimadamore]

On Tue, 18 Apr 2023 13:45:57 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. The pull request contains seven additional commits since the last revision:
> 
>  - fix TestIllegalLink
>  - Merge branch 'PR_21' into RejectPacked
>  - Merge branch 'PR_21' into RejectPacked
>  - add javadoc + fixes for trailing padding
>  - fix check for padding. Add check for trailing padding too
>  - Reject packed structs and structs with extra padding
>  - Check byte order of layouts passed to linker

src/java.base/share/classes/java/lang/foreign/Linker.java line 200:

> 198:  * </table></blockquote>
> 199:  * <p>
> 200:  * Due to limited ABI specification coverage, all the native linker implementations limit the function

`All the native linker implementations support function function descriptors that contain only so-called...`

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PR Review Comment: https://git.openjdk.org/jdk/pull/13164#discussion_r1170619687