> This is the 7th and final PR for [JEP 483: Ahead-of-Time Class Loading & > Linking](https://bugs.openjdk.org/browse/JDK-8315737). > > This PR implements the AOT-linking of invokedynamic callsites: > - We only link lambda expressions (`LambdaMetafactory::metafactory`) and > string concat (`StringConcatFactory::makeConcatWithConstants()`) as the > results of these bootstrap methods do not have environment dependencies and > can be safely cached. > - The resolved CallSites are represented as Java heap objects. Thus, this > optimizations is supported only for the static CDS archive, which can store > heap objects. The dynamic CDS archive is not supported. > > **Review Notes:** > > - Start with `AOTConstantPoolResolver::preresolve_indy_cp_entries()` -- it > checks all indys that were linked during the training run, and aot-links only > those for lambdas and string concats > - `SystemDictionaryShared::find_all_archivable_classes()` finds all the > hidden classes that are reachable from the indy CallSites > - In `MetaspaceShared::preload_and_dump_impl()` we call > `MethodType::createArchivedObjects()` to record all MethodTypes that were > created in the assembly phase. This is necessary because the identity of > MethodTypes is significant (they are compared with the `==` operator). Also > see MethodType.java for the corresponding code that are used in the > production run. > - Afterwards, we enter the safepoint (`VM_PopulateDumpSharedSpace::doit()`). > In this safepoint, > `ConstantPoolCache::remove_resolved_indy_entries_if_non_deterministic()` is > called to remove any resolved indy callsites that cannot be archived. (Such > CallSites may be created as a side effect of Java code execution in the > assembly phase. E.g., the bootstrap of the module system). > > **Rough Edges:** > > - Many archived CallSites references (directly or indirectly) the static > fields of the classes listed under > `AOTClassInitializer::can_archive_initialized_mirror()`, where the object > identity of these static fields is significant. Therefore, we must preserve > the initialized states of these classes. Otherwise, we might run into > problems such as [JDK-8340836](https://bugs.openjdk.org/browse/JDK-8340836). > Unfortunately, the list is created by trial-and-error, and may need to be > updated to match changes in the `java.lang.invoke` and > `jdk.internal.constant` packages. We expect Project Leyden to come with a > general solution to this problem. > - If the identity is significant for a static field in a complex class, but > not all of the static fields of this cl...
Ioi Lam has updated the pull request incrementally with three additional commits since the last revision: - Better fix for JDK-8342438: runtime/cds/SharedBaseAddress.java fails with Parallel and Serial GCs when running with AOTClassLinking enabled - (1) @ashu-mehra review comments - code simplfication; (2) fix bug in last commit - @DanHeidinga comments - removed dead code; added assert with ArchiveBuilder::has_been_buffered(src_ik) ------------- Changes: - all: https://git.openjdk.org/jdk/pull/21143/files - new: https://git.openjdk.org/jdk/pull/21143/files/d3663890..021466dd Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=21143&range=15 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21143&range=14-15 Stats: 90 lines in 7 files changed: 40 ins; 30 del; 20 mod Patch: https://git.openjdk.org/jdk/pull/21143.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21143/head:pull/21143 PR: https://git.openjdk.org/jdk/pull/21143
