RFR: 8293336: AOT-linking of invokedynamic for lambda expression and string concat [v7]

[Ioi Lam]

On Wed, 16 Oct 2024 23:16:00 GMT, Ashutosh Mehra <asmehra at openjdk.org> wrote:

>> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Fixed typo in last commit; fixed header inclusion order
>
> src/hotspot/share/cds/dumpTimeClassInfo.hpp line 45:
> 
>> 43:   bool                         _is_early_klass;
>> 44:   bool                         _has_checked_exclusion;
>> 45:   bool                         _is_required;
> 
> Is this flag only used for hidden classes?

I changed it to `_is_required_hidden_class`.

> src/hotspot/share/cds/heapShared.cpp line 717:
> 
>> 715: };
>> 716: 
>> 717: void HeapShared::find_archivable_hidden_classes_in_object(oop root) {
> 
> If this function find archivable hidden classes, shouldn't there be a check for`is_hidden()` on the InstanceKlass being marked as `required`. Am I missing something?

I added the `ik->is_hidden()` check as you suggested. I also renamed the `find_archivable_hidden_classes_xxx` functions to `find_required_hidden_classes_xxx()`. This is to avoid confusion with `HeapShared::is_archivable_hidden_klass()`, which means "it is possible to archive X", but not "it is necessary to archive X".

> src/hotspot/share/cds/heapShared.cpp line 790:
> 
>> 788: 
>> 789:   init_seen_objects_table();
>> 790:   {
> 
> Why was this scope introduced?

To indicate that these calls must be made while the "see objects" table is available.

> src/hotspot/share/classfile/systemDictionaryShared.cpp line 675:
> 
>> 673: 
>> 674: // Returns true if the class should be excluded. This can be called before
>> 675: // SystemDictionaryShared::check_excluded_classes().
> 
> There are a couple of references to check_excluded_classes() in the comments but this function no longer exists. Can you please update the comment accordingly.

I replaced with the new name of the function `find_all_archivable_classes()`.

> src/hotspot/share/classfile/systemDictionaryShared.cpp line 759:
> 
>> 757:       if (k->is_hidden() && should_hidden_class_be_archived(k)) {
>> 758:         SystemDictionaryShared::check_for_exclusion(k, &info);
>> 759:         if (info.is_excluded()) {
> 
> Is it possible that a hidden class for which `should_hidden_class_be_archived()` returns true is marked for exclusion by `SDS::check_for exclusion`? I guess only possibility is if for some reason its super or interface is excluded. Is that possible?

We filter out hidden classes that cannot be supported (e.g., when a Lambda uses an interface using "old" bytecodes). See

https://github.com/openjdk/jdk/pull/21143/files#diff-fc60af483d061250f01054372fd56eba517a6b8dd37a742a66dfb0e15cb68e40R366-R372

https://github.com/openjdk/jdk/pull/21143/files#diff-2520dedd703ec600cd3037ec0008e9d7f45c6a41acaefac019339641bc749163R149-R152

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PR Review Comment: https://git.openjdk.org/jdk/pull/21143#discussion_r1809709541
PR Review Comment: https://git.openjdk.org/jdk/pull/21143#discussion_r1809709627
PR Review Comment: https://git.openjdk.org/jdk/pull/21143#discussion_r1809709670
PR Review Comment: https://git.openjdk.org/jdk/pull/21143#discussion_r1809709979
PR Review Comment: https://git.openjdk.org/jdk/pull/21143#discussion_r1809710069