RFR: 8304006: jlink should create the jimage file in the native endian for the target platform [v15]

[Mandy Chung]

On Tue, 28 Mar 2023 02:23:05 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:
> 
>  - don't iterate over the properties file keys and instead do lookup when needed
>  - update CDSPluginTest to correctly "simulate" cross-platform test

Looks good.  Minor comment in `CDSPluginTest.java`.

test/jdk/tools/jlink/plugins/CDSPluginTest.java line 98:

> 96:            // the java.base module-info.class to identify the target platform for the image
> 97:            // being generated.
> 98:            Path jdkRoot = Path.of(jlinkPath).getParent().getParent();

Or simply get from `test.jdk` system property:

Suggestion:

          Path jdkRoot = Path.of(System.getProperty("test.jdk"));

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Marked as reviewed by mchung (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/11943#pullrequestreview-1360197068
PR Review Comment: https://git.openjdk.org/jdk/pull/11943#discussion_r1150021265