I reimplemented `SystemDictionaryShared::lookup_super_for_unregistered_class()`
with Java code. This removes hacks in
`SystemDictionary::resolve_with_circularity_detection()` to facilitate future
clean-ups there that are planned by @coleenp. Please see the [JBS
issue](https://bugs.openjdk.org/browse/JDK-8348240) for a discussion of why the
hack was there.
The new Java code is in the `jdk/internal/misc/CDS$UnregisteredClassLoader`
class. I also simplified `UnregisteredClasses::create_classloader()` by moving
some unwieldy C++ `JavaCalls` code into Java.
### How this works:
For example, let's assume you have the following classfiles in foo.jar:
interface MyInterface1 {}
interface MyInterface2 {}
class MyClass extends Object implements MyInterface1, MyInterface2 {}
The CDS classlist file can look like this:
java/lang/Object id: 1
MyInterface1: id: 2 super: 1 source: foo.jar
MyInterface2: id: 3 super: 1 source: foo.jar
MyClass: id: 4 super: 1 interfaces: 2 3 source: foo.jar
When CDS handles the `MyClass: id: 4` line, it calls
`CDS$UnregisteredClassLoader::load()` with the following parameters:
- `name` = "MyClass"
- `superClass` = java.lang.Object
- `interfaces` = {MyInterface1, MyInterface2}
`CDS$UnregisteredClassLoader::load()` will start parsing MyClass.class from
foo.jar. The ClassFileParser will see symbolic references to the supertypes of
`MyClass`. These supertypes will be resolved by
`CDS$UnregisteredClassLoader::findClass()`, using the classes provided by
`superClass` and `interfaces`.
-------------
Commit messages:
- 8348240: Remove SystemDictionaryShared::lookup_super_for_unregistered_class()
Changes: https://git.openjdk.org/jdk/pull/23226/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23226&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8348240
Stats: 342 lines in 9 files changed: 193 ins; 113 del; 36 mod
Patch: https://git.openjdk.org/jdk/pull/23226.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/23226/head:pull/23226
PR: https://git.openjdk.org/jdk/pull/23226
