parsing IOs of a module from Python

[muzafferkal]

Hi,
I'm very new to this project but hopeful that it could do what I need:
I'd like to use it as a front-end to either Magma or Amaranth to generate wrappers from existing RTL modules. The scheme I have in mind is to have a python call which is basically "interfaces/ios from verilog" such that it will parse the ports of the verilog file and generate objects which I can use in magma/amaranth to connect to other modules. As such I need some way to associate all bit-vectors to their respective busses (say axi-stream or full etc), pull unrelated inputs/outputs to a separate group, identify clocks and resets etc. Any idea how I should go about doing this use slang? Any guidance/direction or one hopes, existing implementation similar to this would be great.
Best
-K

[MikePopoloski]

Yes, slang can be used for this. The AST provides full type information for the whole design, so you can walk the modules and collect all ports and their internal connections. Whether something is a clock or a reset or whatever isn't identified directly by the language so it'll be up to your particular set of heuristics or project conventions to find them though.

[muzafferkal]

is there a doc which shows the object model in pyslang? I see the simple example but it's not obvious how to parse the tree.root hierarchy to see if a certain instance is instantiated or not. There is a parent attribute but it doesn't seem to be what I need. Any guidance or more pyslang examples would be appreciated.

[MikePopoloski]

There isn't Python-specific documentation currently. The docs I do have are here: https://sv-lang.com/ but there isn't specific reference documentation for the syntax tree; it mostly follows the language grammar from the LRM. The grammar itself is defined in https://github.com/MikePopoloski/slang/blob/master/scripts/syntax.txt which I think is actually fairly readable; the members listed there should be directly accessible from Python, but if you're not intimately familiar with the language syntax it can be a little difficult to connect the dots. I would definitely accept contributions in the form of additional documentation if you figure it out and feel inspired to contribute.

[apsarras]

hi @muzafferkal, I'm trying to achieve the same thing (parse the module -> create a wrapper) but I'm also very new to this and it's not straight-forward. Did you manage to use pyslang for this? Can you share example code?

[suzizecat]

Hello there !
As a starter, you may find interesting to have a look at this visitor I've made for the purpose of getting the IOs of any modules and compose the hierarchy of a design. The result is then stored in a json structure using nlhomann JSON library.
You may also have a look at this one made in order to generate the "black box" view of a module for a "instanciate module" function.