RFR: 8331497: Implement JEP 483: Ahead-of-Time Class Loading & Linking [v4]

[Ashutosh Mehra]

On Thu, 24 Oct 2024 03:01:54 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> This is an implementation of [JEP 483: Ahead-of-Time Class Loading & Linking](https://openjdk.org/jeps/483).
>> 
>> ----
>> Note: this is a combined PR of the following individual PRs
>> - https://github.com/openjdk/jdk/pull/20516
>> - https://github.com/openjdk/jdk/pull/20517
>> - https://github.com/openjdk/jdk/pull/20843
>> - https://github.com/openjdk/jdk/pull/20958
>> - https://github.com/openjdk/jdk/pull/20959
>> - https://github.com/openjdk/jdk/pull/21049
>> - https://github.com/openjdk/jdk/pull/21143
>
> Ioi Lam has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - 8342907: Implement AOT testing mode for jtreg tests (authored by @katyapav)
>  - disable test that fails with hotspot_runtime_non_cds_mode

src/hotspot/share/cds/aotConstantPoolResolver.cpp line 113:

> 111: 
> 112:     if (CDSConfig::is_dumping_aot_linked_classes()) {
> 113:       // Need to call try_add_candidate instead of is_candidate, as this may be called

I think in this version of the code this method is not used before `AOTClassLinker::add_candidates`. Can we switch back to `is_candidate` then?

src/hotspot/share/cds/heapShared.hpp line 298:

> 296:   static SeenObjectsTable *_seen_objects_table;
> 297: 
> 298:   // The "special subgraph" contains all the all archived objects that are reachable

an extra `all` in the comment

src/hotspot/share/classfile/systemDictionaryShared.cpp line 685:

> 683:     InstanceKlass* ik = InstanceKlass::cast(k);
> 684: 
> 685:     if (SafepointSynchronize::is_at_safepoint()) {

Why is this piece of block required?
It calls `is_excluded_class` which reads `DumpTimeClassInfo::_excluded` without checking for `has_checked_exclusion`. That means it can return false (the default value) even for classes that may later be marked for exclusion by `check_for_exclusion(ik, p)`.
<del>On the same note, I think we should add an assert in `DumpTimeClassInfo::is_excluded` that `has_checked_exclusion()` is true.<del>

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PR Review Comment: https://git.openjdk.org/jdk/pull/21642#discussion_r1816853423
PR Review Comment: https://git.openjdk.org/jdk/pull/21642#discussion_r1816996074
PR Review Comment: https://git.openjdk.org/jdk/pull/21642#discussion_r1817159936