On Mon, 15 Sep 2025 23:20:47 GMT, Ioi Lam <[email protected]> wrote:

>> This PR adds a new annotation, `@AOTInitialize` that forces a class to be 
>> (a) initialized in the AOT assembly phase, and (b) stored in the AOT cache 
>> in an already initialized state. This means that all the static fields in 
>> this class will be immediately available upon JVM bootstrap when the AOT 
>> cache is used in an application's production run.
>> 
>> This PR annotates a single class, `jdk.internal.math.MathUtils`. More 
>> classes will be added in future PRs.
>> 
>> If a class `K` has the `@AOTInitialize` annotation, the same annotation must 
>> be also added to
>> - All of `K`'s super classes
>> - All of `K`'s super interfaces that require to be initialized when `K` is 
>> initialized (see JVMS 5.5. Initialization, step 7; also C++ function 
>> `InstanceKlass::interface_needs_clinit_execution_as_super()`
>> 
>> Note, the check of the above requirement has been moved to 
>> `AOTClassInitializer::check_aot_annotations()`. The previous check in 
>> `ClassFileParser` was not executed because the class is loaded in the AOT 
>> training run, where `CDSConfig::is_initing_classes_at_dump_time()` returns 
>> `false` (this function returns `true` only in the AOT assembly phase).
>> 
>> This annotation is awfully similar to `@AOTSafeAnnotation`, and I am not 
>> sure if we need both. Please see the javadoc in `@AOTInitialize` to see the 
>> difference between the two annotations.
>
> Ioi Lam has updated the pull request incrementally with one additional commit 
> since the last revision:
> 
>   Exclude more GC heap size tests as AOT cache size has increased for "make 
> test JTREG=AOT_JDK=onestep ..."

> This annotation is awfully similar to @AOTSafeAnnotation, and I am not sure 
> if we need both

Maybe we do want both. @AOTSafeAnnotation is weaker than @AOTInitialize because 
the former only initializes classes optionally when we find it is needed. If we 
only had @AOTInitialize then we would lose that optionality. It may not make 
much difference now -- we probably only have these annotations for JDK classes 
that would need to be class-inited whatever the training regime. However, as we 
expand use of the annotation might we risk initing classes and including their 
state in the archive without necessarily seeing any benefit?

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PR Comment: https://git.openjdk.org/jdk/pull/27024#issuecomment-3297343820

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