Re: [Csnd-dev] pass-by-ref

This is great. Regarding passing by ref for all arguments, does that not
change the semantics of opcodes? I for sure would not expect that modifying
a k- variable inside an opcode could change the value outside it

Cheers, Eduardo

On Mon, Feb 19, 2024, 21:43 Steven Yi <[email protected]> wrote:

> Hi All,
>
> I managed to get through an initial implementation of pass-by-ref for
> UDOs. Took a while to do analyses of the code to get to this point,
> but hopes are that it should be quicker to iterate upon from here with
> this base implementation.
>
> If you're interested to try it out, the branch is:
>
> feature/pass-by-ref
>
> Some notes on this implementation:
>
> 1. I moved UDO-related code out from insert.c/.h to a separate udo.c/.h
> file.
> 2. I implemented this only for new-style UDOs. There was discussion
> about making this something we could control on a per-argument basis,
> but starting with this simplified what had to get figured out. I also
> wonder if it wouldn't be a good idea to simply go with this, since it
> makes UDOs have the same characteristics of pass-by-ref as native
> opcodes. It would also be safe to do this for backwards compatibility
> and keep pass-by-value for old-style UDOs.
> 3. I added a new ##userOpcode2 entry that gets used for new-style
> UDOs. It does not have any perf-time code. useropcdset_newstyle
> handles ref finding and setting with the following algorithm:
>
> * 1. Iterate through the init chain to find xin/xout opcodes.
> * 2. When found, lookup names of input and output variables for this
> current UDO instance.
> * 3. Setup a map of input/output variable names to passed-in arg pointers
> * 4. Iterate through the init chain to find references to xin/xout
> vars and set the pointers to the input/out variable argument pointer
> addresses.
> * 5. Iterate through the perf chain to find references to xin/xout
> vars and set the pointers to the input/out variable argument pointer
> addresses.
>
> xinset and xoutset were also modified to skip copying of UDO in/out
> args to/from IOBUFS when inside a new-style UDO.
>
> At the moment, all csd tests are passing including the new test I
> added while doing dev. There's a number of additional tests to add to
> ensure this works with UDOs calling UDOs, structs, etc. There's also
> performance testing to do to see how well this affects things like
> passing f-sigs and arrays into UDOs. There's also some known issues
> with returning constants from UDOs and some other arg types I have to
> check to see if they are working or not. Also, there is a bigger issue
> of what to do for local ksmps (will likely revert to pass-by-value for
> short-term) as well as how to handle oversampling (i.e., local sr).
>
> I'm pretty excited to get past this initial implementation. Feedback
> and any tests are welcome and appreciated.
>
> Thanks!
> Steven
>