Integrated: 8338939: Simplify processing of hidden class names

[Markus Grönlund]

On Sun, 25 Aug 2024 18:29:47 GMT, Markus Grönlund <mgronlun at openjdk.org> wrote:

> Greetings,
> 
> The name symbol for hidden (anonymous) classes has evolved. Initially, it consisted of only a base class name, e.g., "java/lang/invoke/LambdaForm$BMH", so JFR had to introduce a scheme for disambiguating one anonymous class from another.
> 
> The scheme (which still exists in JFR) appends the Java class mirror's hashcode to the base class name, e.g., "java/lang/invoke/LambdaForm$BMH/22626602".
> 
> With [JDK-8238358](https://bugs.openjdk.org/browse/JDK-8238358), the disambiguation of hidden class names is now intrinsic to the processing by the ClassFileParser. This is done by appending the InstanceKlass address to the base class name, e.g., "java/lang/invoke/LambdaForm$BMH+0x000000001d190000".
> 
> An argument can be made that JFR specialization for hidden (anonymous) classes may no longer be necessary. Indeed, the result now involves a "double" disambiguation: e.g., "java/lang/invoke/LambdaForm$BMH+0x000000001d190000/231202600".
> 
> It is now possible to simplify the handling of hidden (anonymous) class names, which avoids using the Java mirror oop. We might want to keep the "/" construct as that might be an implicit invariant on users' expectations (quickly done by replacing "+" with "/").
> 
> Testing: jdk_jfr
> 
> Thanks
> Markus

This pull request has now been integrated.

Changeset: 0f667103
Author:    Markus Grönlund <mgronlun at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/0f667103db7842fe9d3399f56baee0a5def4529e
Stats:     59 lines in 2 files changed: 2 ins; 40 del; 17 mod

8338939: Simplify processing of hidden class names

Reviewed-by: egahlin

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PR: https://git.openjdk.org/jdk/pull/20708