2017/09/26

15:27

Ok, the CodeDecompiler is a bit unwieldy in that it seems quite messy and will end up being a giant mess. The JIT is going to be quite large in retrospect, it already is large and I am not too sure it would be that possible to condense it into a smaller amount. Having a small clean amount of code for the JIT would be really really nice. I keep getting stuck on the JIT because handling the class file is a complex process.

15:32

I mean the class decoding code is quite complex when it can be probably far simpler in operation. Maybe it is not possible to have a JIT that is clean and really the only thing that there can be is a giant mess. There has to be a way to have a nice and clean order.

15:36

Maybe the individual units are too intertwined, the bulk of the subpackages in the JIT are interconnected. The class decoder does the verification calls and such. The class structure is built with the structure code. The one thing I do not like is the intertwined nature. Also the class information is pretty much duplicated by the structure system. Also I have a hope that the JIT would run on systems with a small amount of memory, but that seems a bit unlikely right now. I could and probably should require the JIT not be limited by memory and execution speed. So that would be the best choice.

15:44

You could run the JIT on say a Commodore 64, but really why would you want to? The length of time it would take would essentially be forever. Although you would not be able to run programs which are not fixed, there might not even be the memory or disk space for that.

15:55

So basically I will make the class format just be represented as a bunch of classes which contain a representation of the instructions. The class representation will know nothing of what goes on in the JIT. There would just be classes which go through all methods which can then be compiled on an instructional basis. So most of the code will be the same as before, just in a different fashion.

15:58

I can call the new class representation cff for Class File Format.

16:07

I think I will design the JIT to really take advantage of stuff such as whole program optimization. I want the resultant binaries to be really tiny and I could do these optimizations, such as inlining and other things potentially. I can also have like attributes for optimization in methods. So methods which just read a field and for the most part, just return that given field. This can be recursive so that method overhead is just removed. I think knowing and loading everything during compilation would be the most optimal.

16:14

I should also probably have debugging information, because while it will increase waste it will provide location based information.

16:16

I would say the first stage of the JIT processing should just load every class that exists.

16:18

Worry about binaries later.

16:21

Ok so, what I need is a class called JITInput. This class reads all of the resources and class files, it then it provided as input for the JIT itself. It knows nothing about the JIT or anything that it does. It just provides itself as input for everything.

16:32

At least when everything is loaded, multiple threads can be taken advantage of for the most part. Actually with a sorted tree map, I can have it ordered based on an index while allowing multiple threads to perform the loading of the input streams. So I can multi-thread loading of JARs from the disk.