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

[Ioi Lam]

On Fri, 25 Oct 2024 18:14:38 GMT, Ashutosh Mehra <asmehra at openjdk.org> wrote:

>> 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>
>
> Does the check `SafepointSynchronize::is_at_safepoint` imply that exclusion checks for all classes have already been done?

I renamed the public function to `should_be_excluded(InstanceKlass*)` to avoid confusion with the private function `check_for_exclusion(InstanceKlass*, DumpTimeClassInfo*)`. I also added code to make sure that exclusion has been checked for the class, even when in safepoint.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21642#discussion_r1823688154