RFR: 8304006: jlink should create the jimage file in the native endian for the target platform [v17]

[Jaikiran Pai]

On Wed, 29 Mar 2023 01:40:36 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Can I please get a review for this change which proposes to fix the issue reported in https://bugs.openjdk.org/browse/JDK-8206890?
>> 
>> The `jlink` command allows a `--endian` option to specify the byte order in the generated image. Before this change, when such a image was being launched, the code would assume the byte order in the image to be the native order of the host where the image is being launched. That would result in failure to launch java, as noted in the linked issue.
>> 
>> The commit in this PR, changes relevant places to not assume native order and instead determine the byte order by reading the magic bytes in the image file's header content.
>> 
>> A new jtreg test has been added which reproduces the issue and verifies the fix.
>
> Jaikiran Pai has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - cleanup test - rename method and update code comment as suggested by Alan
>  - Rename KNOWN_ENDIANNESS to PLATFORM_PROPERTIES

> See draft PR #14063 for a proposal

Hello Roger, I had a look at that draft PR.

The introduction of `Architecture.byteOrder()` and `Architecture.lookupByName(archName)` in that PR, I believe is going to help us here. I could then read the `ModuleTarget` attribute and use the `Architecture.lookupByName()` to get hold of the target architecture and thus its endianness through `Architecture.byteOrder()`. That would then mean we no longer need the `target.properties` file that was previously proposed in this PR.

I haven't had a chance to refresh this PR to resolve the merge conflicts. I hope to get to it soon.

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PR Comment: https://git.openjdk.org/jdk/pull/11943#issuecomment-1561023227