[lworld] RFR: 8368031: Apply mainline changes to support preview mode work into Valhalla

[Chen Liang]

On Thu, 18 Sep 2025 22:56:36 GMT, David Beaumont <duke at openjdk.org> wrote:

> This change rolls up four necessary (and hopefully sufficient) mainline changes needed in Valhalla for the preview mode work.
> 
> These were applied bottom-to-top in a Valhalla repo by applying patches created from a recent mainline JDK repo, using "git show" and "git apply".
> 
> Note that I needed to use "--theirs" to resolve a small set of mismatches due to other non-exact patching which has already occurred for these classes. I see no intermediate changes in any classes by anyone else, no sign of overwriting other changes, and internal testing is passing. I would have preferred if everything applied 100% clean, but things like copyright years were fixed in one version and not in the other.
> 
> [Apply patch from mainline hash: 3fae6013c6]
> 8365532: java/lang/module/ModuleReader/ModuleReaderTest.testImage fails
> 
> [Apply patch from mainline hash: 0b05b7cc92]
> 8365436: ImageReaderTest fails when jmods directory not present
> 
> [Apply patch from mainline hash: 06ce9e89ab]
> 8365467: Issues with jrtfs implementation for exploded run-time images
> 
> [Apply patch from mainline hash: 166210719e]
> 8367005: ImageReader refactor caused performance regressions for startup and footprint

Looks like what we had in mainline.

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Marked as reviewed by liach (Committer).

PR Review: https://git.openjdk.org/valhalla/pull/1600#pullrequestreview-3242362477