LibJVM: Start parsing class files #11500
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The parser is not complete and the interface will change as the runtime
gets developed.
But the parser is already able to parse the classfile of a simple Java
program:
```java
class Main {
public static void main(String[] args) {
}
}
```
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Looks like you're missing a CMakeLists.txt file for LibJVM |
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From our contributing guidelines:
I haven't seen any discussion about building a JVM anywhere. SerenityOS has nothing to do with Java, so why does it suddenly need a JVM? |
I saw a single mention on the Discord
And I think it came up in office hours a few times, does Serenity run Minecraft, support Java ... with the typical answer, no but you could work on that. But yes I understand that a second VM might not fit into Serenity and that nobody wants a dead library. |
The constant pool now has its own class ConstantPool. Also the invidivual constants now have nicer accesors which lookup their indices in the given constant pool.
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If you want to build a JVM, I suggest doing it as a completely separate project from SerenityOS, as there is no natural need for Java anywhere in this system. :) |
The
ClassFileParseris able to parse simple classfiles into aClassFilestructure.The parser successfully consumes the .class file of the most basic Java program:
There is still a lot missing but I want to have this overall structure reviewed before I flesh out the parser and start using the ClassFile interface in the Runtime.
I'm new to modern C++ so there's probably lots to improve.
One design decision I made, is that the ClassFile structure holds onto the buffer containing the contents of the
.classfile. This is because fields of the ClassFile structure point into the buffer e.g. for strings or bytecode.Another design decision is using
unionsinstead of inheritance to represent constants in the java constant pool.