On Wed, 2 Jul 2025 00:18:28 GMT, Ioi Lam <[email protected]> wrote:
> The CDS full module graph is supposed to contain a snapshot of the boot
> layer, which has 3 unnamed modules for the boot, platform and system class
> loaders. Each unnamed module is represented by a `java.lang.Module` Java
> object and a `ModuleEntry` C++ object.
>
> Currently, we archive only the `java.lang.Module` for the platform and system
> loaders. The other 4 objects are dynamically created in the production run
> while executing Java bytecodes during VM bootstrap.
>
> With this PR, we archive all of the above 6 objects when
> `CDSConfig::is_dumping_full_module_graph()` is true.
>
> This is required for
> [JDK-8350550](https://bugs.openjdk.org/browse/JDK-8350550), as we need the
> `java.lang.Module` object for archived classes in the unnamed module of the
> boot loader prior to executing any Java code.
>
> We also archive the `ModuleEntry` objects for the 3 unnamed modules for
> uniformity, as these objects are already archived for named modules.
src/hotspot/share/classfile/modules.cpp line 777:
> 775: if (CDSConfig::is_using_full_module_graph()) {
> 776: precond(unnamed_module ==
> ClassLoaderDataShared::archived_boot_unnamed_module());
> 777: unnamed_module->restore_archived_oops(boot_loader_data);
If you're restoring the module oop from the archive, what is the module oop
passed into this that the rest of the code is using?
src/java.base/share/classes/jdk/internal/loader/BootLoader.java line 71:
> 69: }
> 70: jla.addEnableNativeAccess(UNNAMED_MODULE);
> 71: setBootLoaderUnnamedModule0(UNNAMED_MODULE);
Here it's being called. Should this be called?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/26082#discussion_r2213207332
PR Review Comment: https://git.openjdk.org/jdk/pull/26082#discussion_r2213222965
