RFR: 8360555: Archive all unnamed modules in CDS full module graph

[Ioi Lam]

On Mon, 21 Jul 2025 17:51:34 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> The callstack is:
>> 
>> 
>> jdk.internal.loader.BootLoader.setBootLoaderUnnamedModule0(java.base at 26-internal/Native Method)
>> jdk.internal.loader.BootLoader.<clinit>(java.base at 26-internal/BootLoader.java:71)
>> jdk.internal.module.ModuleBootstrap.boot(java.base at 26-internal/ModuleBootstrap.java:162)
>> java.lang.System.initPhase2(java.base at 26-internal/System.java:1932)
>> 
>> 
>> Both the Java code and the native code have a handle to this unnamed module oop. The `precond` checks that they indeed are pointing the same oop.
>> 
>> Also, even though the oop is archived, we still need to set up some native states inside the `unnamed_module->restore_archived_oops(boot_loader_data)` call. E.g., set up the `OopHandle` that binds the oop to the `ModuleEntry`.
>> 
>> ---------------
>>> what are you saving by archiving the unnamed module?
>> 
>> It's for [JDK-8350550](https://bugs.openjdk.org/browse/JDK-8350550)) -- I want to be able to reference the unnamed module before executing any Java code, so that archived classes can be loaded at the very beginning of `vmClasses::resolve_all()`. See my draft PR: https://github.com/openjdk/jdk/pull/26375
>> 
>> ---------------
>> Currently, we still execute a lot of Java code when setting up the archived module graph (inside `ModuleBootstrap.boot()`. I am working on a way to enable the archived module graph without executing any Java code (which will be a few REFs after [JDK-8350550](https://bugs.openjdk.org/browse/JDK-8350550)), so this call will eventually be gone.
>
> Ok, I see.  At this point, you're just checking that what you've referred to before loading the unnamed module matches what you've previously saved in the shared archive. Did I get that right?

Yes, it's checking that the Java and C++ code both found the same archived unnamed module.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26082#discussion_r2219925684