On Wed, 17 Dec 2025 20:04:48 GMT, Ioi Lam <[email protected]> wrote: >> In legacy CDS, Java objects used by certain classes are computed ahead of >> time using "object subgraphs" >> >> https://github.com/openjdk/jdk/blob/1bbbce75c5e68429c2a32519eb3c36d964dcdf57/src/hotspot/share/cds/heapShared.cpp#L168-L171 >> >> Examples of subgraphs: >> >> - `java.lang.Integer$IntegerCache::cache` >> - `jdk.internal.module.ArchivedBootLayer::bootLayer` >> >> The implementation requires special code (in both Java and C++) to be >> executed when a CDS archive is created or loaded. As a result, we have an >> execution model that's difficult to implement/extend and the behavior is >> hard to understand. >> >> To move towards the AOT Cache Snapshot Model >> ([JDK-8365645](https://bugs.openjdk.org/browse/JDK-8365645)) we should >> replace the subgraphs with the use of `@AOTSafeClassInitializer`, and if >> necessary, `@AOTRuntimeSetup`. This will simplify the current >> implementation, and make it possible to extend AOT-initializations to more >> core classes. >> >> Note, the use of `@AOTSafeClassInitializer` requires `-XX:+AOTClassLinking`. >> For the time being, we retain the old CDS object subgraph code to cover the >> `-XX:-AOTClassLinking` cases. Such code will be marked with comments like >> `/* Legacy CDS archive support (to be deprecated) */`. All future AOT >> creation of Java objects will be done with `@AOTSafeClassInitializer`. > > Ioi Lam has updated the pull request incrementally with one additional commit > since the last revision: > > Fixed test case -- the regexp pattern could match the stats for the > subgraphs table, which now has a single entry
The new tests look fine to me. ------------- Marked as reviewed by liach (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/28736#pullrequestreview-3589877162
