Support for custom CIL instructions

Hi,

For a project I’m currently working on, I need to be able to insert custom CIL instructions into a method body (ones that are understood by the runtime I’m targeting). Basically, I just want to be able to provide dnlib with custom OpCode instances that inform it about how to decode/encode these instructions, calculate stack usage and control flow, etc.

From what I can gather looking at the source, what would need to happen for this to be possible is:

• OpCode would need to be made extensible in some form (probably just a public constructor).
• There would need to be some place in the API for registering custom OpCode instances.
• MethodBodyReaderBase and a few other places need to be made aware about the experimental opcode range (0xf0…0xfb).

There may of course be other required changes that I’m not aware of, but I think that’s the gist of it.

Would a patch for this be welcome? If so, what would be an acceptable design for this?

[0xd4d]

I would expect that if you want to define your own custom opcodes, you’d create a table with 256 values in it so an array should be enough. 0xF0-0xFB can then be overridden to use those arrays (if they’re not null).

[0xd4d]

Add new overloads

• MethodBodyReader: an extra contex arg, pass it to base
• CreateCilBody: two of these call CreateCilBody() and these two methods need to get a new overload with a contex arg

The opResolver is usually a module but we can’t assume it.