RFR: 8304006: jlink should create the jimage file in the native endian for the target platform [v19]

[Jaikiran Pai]

On Wed, 12 Jul 2023 19:24:22 GMT, Mandy Chung <mchung at openjdk.org> wrote:

>> Jaikiran Pai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 45 commits:
>> 
>>  - move copyright before imports in the new test
>>  - add a new test for jlink --endian usages
>>  - merge latest from master branch
>>  - use newly introduced Architecture.byteOrder() API
>>  - merge latest from master branch
>>  - update jdk.tools.jlink.internal.Platform class to be aware of non-current platform's endianness
>>  - remove no longer needed constructor
>>  - merge latest from master branch
>>  - foo
>>  - merge latest from master branch
>>  - ... and 35 more: https://git.openjdk.org/jdk/compare/753bd563...962d542d
>
> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/Jlink.java line 168:
> 
>> 166:             this.output = output;
>> 167:             this.modules = Objects.requireNonNull(modules);
>> 168:             this.endian = endian;
> 
> `JlinkConfiguration` does not need to know the endianness.   Only the image builder needs it.   Probably good to take the `endian` parameter out from `JlinkConfiguration` and instead pass the value of `--endian` to `JlinkTask::createImageProvider` like other jlink options.

Done. The updated PR no longer has the endian value in the `JlinkConfiguration`

> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/JlinkTask.java line 412:
> 
>> 410: 
>> 411:         // First create the image provider
>> 412:         ImageHelper imageProvider = createImageProvider(config,
> 
> formatting nit: line 413-415 should be adjusted to align the parameters.

Fixed

> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/JlinkTask.java line 568:
> 
>> 566:         Map<String, Path> mods = cf.modules().stream()
>> 567:             .collect(Collectors.toMap(ResolvedModule::name, JlinkTask::toPathLocation));
>> 568:         return new ImageHelper(cf, mods, config.getByteOrder(), retainModulesPath, ignoreSigning,
> 
> Also we can move the logic of determining the endianess of the target platform out of `ImageHelper`.   Evaluate the target platform and endianness here and pass to `ImageHelper`.
> 
> Suggestion:
> 
>         // endian is the value specified via --endian and a new parameter to createImageProvider 
>         Platform targetPlatform = targetPlatform(cf, modsPaths);
>         ByteOrder targetOrder = endian != null ? endian : targetPlatform.arch().byteOrder();
>         return new ImageHelper(cf, mods, targetOrder, retainModulesPath, ignoreSigning,

I've updated the PR to use this suggestion. With this suggested change, the code is much more cleaner and I now just pass the `targetPlatform` to the `ImageHelper` constructor.

> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/JlinkTask.java line 856:
> 
>> 854:         // returns true if the current platform's "jmods" directory is the parent of the
>> 855:         // passed javaBasePath
>> 856:         private static boolean isJavaBaseFromCurrentPlatform(Path javaBasePath) throws IOException {
> 
> This method checks if we are jlinking the JMOD files from the default module path.   This is not exactly checking if `java.base` matches the current platform since there are other possible setups too.    Suggest to rename the method name to `isJavaBaseFromDefaultModulePath`.   So the comments should also be updated to reflect that.

Renamed as suggested and updated the comments as well in the updated version of the PR.

> src/jdk.jlink/share/classes/jdk/tools/jlink/internal/JlinkTask.java line 857:
> 
>> 855:         // passed javaBasePath
>> 856:         private static boolean isJavaBaseFromCurrentPlatform(Path javaBasePath) throws IOException {
>> 857:             Path currentPlatformJmods = getDefaultModulePath();
> 
> Suggestion:
> 
>             Path defaultModulePath = getDefaultModulePath();

Done

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

PR Review Comment: https://git.openjdk.org/jdk/pull/11943#discussion_r1262425330
PR Review Comment: https://git.openjdk.org/jdk/pull/11943#discussion_r1262426029
PR Review Comment: https://git.openjdk.org/jdk/pull/11943#discussion_r1262427486
PR Review Comment: https://git.openjdk.org/jdk/pull/11943#discussion_r1262425722
PR Review Comment: https://git.openjdk.org/jdk/pull/11943#discussion_r1262425873