On Tue, 16 Sep 2025 17:40:48 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` (also the 
>> object hierarchy root class, `Object.class`, which has no associated AOT 
>> initialization but is required for completeness). 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 `@AOTSafeClassInitializer`, 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:
> 
>   Added logging about @AOTSafeClassInitializer classes that have not been 
> initialized

> 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).

So this is a bug already present in the code and effectively disables super 
type checks for AOTSafeClassInitializer annotation, is that right?
There is a reference to ClassFileParser in the documentation for 
AOTSafeClassInitializer. I think it needs to be updated as well: 
https://github.com/openjdk/jdk/blob/18dc186a8f4820ed78c21173713dd127ef512e1f/src/java.base/share/classes/jdk/internal/vm/annotation/AOTSafeClassInitializer.java#L124-L129

src/hotspot/share/cds/aotClassInitializer.cpp line 53:

> 51: 
> 52:   if (ik->force_aot_initialization()) {
> 53:     assert(ik->is_initialized(), "must have been initialized before this 
> check");

Is it not possible for a jdk class to be loaded but not initialized during an 
application run? If such a jdk class is marked with AOTInitialize annotation, 
this assert would trigger during the assembly phase.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/27024#issuecomment-3304237468
PR Review Comment: https://git.openjdk.org/jdk/pull/27024#discussion_r2356493896

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