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AOT Support for Method Handles (OpenJDK Implementation) #19993
This issue describes a staged approach to enable AOT support for Method Handles (MH) for the OpenJDK Implementation (JDK17+); only AOT w/ SVM will/can be supported.
1. Unresolved Dispatch
Unresolved dispatch involves performing a resolved interpreter dispatch using a dummy linkToStatic method as the target method. For AOT, this requires only validating the polymorphic signature of the dummy linkToStatic method; the rest is handled by the resolved interpreter dispatch infrastructure which is already handled with the SVM.
Resolved dispatch is considerably more involved, and has a few more requirements:
Add ability to store the generated LambdaForm class into the SCC
Add validation record for invokeHandle/invokeDynamic
Store class chain of the class of the target method from member name
Remember method index (into the target method's class) of the target method
This is to to compare the method name indirectly; if the class chain validation succeeds, then the method index will refer to the same method name and bytecodes.
Remember whether the appendixObject is NULL or not
3. KOT enabled optimization
Resolved dispatch by itself isn't sufficient to generate optimal code; the compiler needs the Known Object Table (KOT) to "see through" a potential chain of method handles to be able to properly optimize. Thus, the AOT support will need to be added for the KOT. This can be implemented in a fairly straightforward approach using the SVM.
dsouzai
commented
3 months ago
This issue describes a staged approach to enable AOT support for Method Handles (MH) for the OpenJDK Implementation (JDK17+); only AOT w/ SVM will/can be supported.
1. Unresolved Dispatch
Unresolved dispatch involves performing a resolved interpreter dispatch using a dummy
linkToStaticmethod as the target method. For AOT, this requires only validating the polymorphic signature of the dummylinkToStaticmethod; the rest is handled by the resolved interpreter dispatch infrastructure which is already handled with the SVM.2. Resolved Dispatch
Resolved dispatch is considerably more involved, and has a few more requirements:
3. KOT enabled optimization
Resolved dispatch by itself isn't sufficient to generate optimal code; the compiler needs the Known Object Table (KOT) to "see through" a potential chain of method handles to be able to properly optimize. Thus, the AOT support will need to be added for the KOT. This can be implemented in a fairly straightforward approach using the SVM.