[Calyx] Add sequential memories

[andrewb1999]

Adds new calyx.seq_mem op which, in contrast to calyx.memory, has sequential reads. Sequential reads on memories is much more realistic than combinational reads for most use cases. Native Calyx is planning to deprecate std_mem soon as many users are accidentally using that instead of seq_mem, which can significantly hurt the QOR.

We will still need to change the LoopScheduleToCalyx pass to use calyx.seq_mem instead of calyx.memory before deprecating std_mem, which is something I am working on while adding loop schedule support for sequential loops.

[rachitnigam]

Broken documentation link but otherwise looks good

[cgyurgyik]

Thanks!

[cgyurgyik]

This needs to be fixed here as well

[mortbopet]

I know this PR has already received approvals, and I'm not going to block it if you really want to merge. But i think it's somewhat smelly code that the return values of this op isn't implemented in what i'd consider the canonical way to do this.

[mortbopet]

Really not a big fan of the long results type list (: i1, i32, i1, i1, i32, i1) when most (all?) of those are known based on the memory type (size attributes).
Could change the results to

let results = (outs Variadic<AnySignlessInteger>:$addrs, AnySignlessInteger:$writeData, I1:$wrEn, I1:$wrDone, I1:$clk, AnySignlessInteger:$rdData, I1:$rdEn, I1:$rdDone)>

and using the InferTypeOpInterface. This would also be much more canonical, in that all of the custom getters that you've implemented will be autogenerated.

[andrewb1999]

I agree, but I am just following the method used on existing Calyx ops for now. This op functions very similarly to the existing calyx.memory op. Maybe I can merge this PR and then work on another PR at a later date to bring all of the Calyx ops inline with the suggestions you make?

[mortbopet]

Works for me - a general cleanup in this aspect would be nice!

[andrewb1999]

I'm going to go ahead and merge this and then work on a PR that infers the types for all Calyx primitives, because I agree that the long list of types is pretty annoying.