RFR: 7903933: Move sharable items from different generations to a common file [v6]

[Maurizio Cimadamore]

On Fri, 18 Apr 2025 15:35:08 GMT, Nizar Benalla <nbenalla at openjdk.org> wrote:

>> Please review this patch to move the `C_*` layouts and the static utility methods into separate classes: `LayoutUtils.java` and `FFMUtils.java`, respectively.
>> 
>> - The names could later be personalized through a JSON configuration.
>> - We can use static imports if the `-t` option is no used and the files are generated into the default package, in that case we use the classname to call the static methods or use the `C_*` constants.
>> 
>> Some tests had to be modified slightly, either by adding new static imports or replacing classnames.
>
> Nizar Benalla has updated the pull request incrementally with one additional commit since the last revision:
> 
>   make utility classes final with a private constructor

src/main/java/org/openjdk/jextract/impl/ToplevelBuilder.java line 67:

> 65:         SourceFileBuilder sfb = SourceFileBuilder.newSourceFile(packageName(), SHARED);
> 66:         HeaderFileBuilder sharedBuilder = new HeaderFileBuilder(sfb, SHARED, null, SHARED);
> 67:         sharedBuilder.appendBlankLine();

There seems to be a lot of overlapping between the code here and the one in `nextHeader` -- especially now that the first header is not really meant to have a lot of special things (the only exception being the symbol lookup logic).

src/main/java/org/openjdk/jextract/impl/ToplevelBuilder.java line 80:

> 78:         first.classBegin();
> 79:         first.emitDefaultConstructor();
> 80:         first.emitRuntimeHelperMethods();

Shouldn't the runtime helper methods end up in the shared class?

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PR Review Comment: https://git.openjdk.org/jextract/pull/278#discussion_r2063996942
PR Review Comment: https://git.openjdk.org/jextract/pull/278#discussion_r2063993553