[Transforms][circt-synth] Add HierarchicalRunner pass #8254
Conversation
Add a new pass that allows running passes under hierarchy. This is useful when we want to run synthesis passes only on real designs. This implementation is based on MLIR's upstream CompositePass and Inliner utilities. The pass takes a pipeline string and runs it on modules in the design hierarchy. It supports configurable options including the pipeline to run under hierarchy, the name of the top-level module, and whether to include bound instances in the hierarchy traversal. The implementation updates circt-synth tool with the required library dependencies and necessary dialect and pass headers.
| auto *node = worklist.pop_back_val(); | ||
| if (!node) | ||
| continue; |
There was a problem hiding this comment.
I'm curious about the pop-out node. In what situation will it be nullptr?
There was a problem hiding this comment.
Yeah good point. It wouldn't be possible.
| for (auto *child : *node) { | ||
| auto childOp = child->getInstance(); | ||
| if (!childOp || | ||
| (!includeBoundInstances && childOp->hasAttr("doNotPrint"))) |
There was a problem hiding this comment.
Does the "doNotPrint" attribute have the same semantics as "set_dont_touch" in SDC?
There was a problem hiding this comment.
"doNotPrint" is used for instances instantiated by SystemVerilog bind. Normally they won't be instantiated in the synthesizable parts. It's not good that we are relying on this vaguely defined attribute, and we have wanted to fix (See #2231) but no effort has been made so far.
|
Thank you for the review!
It's generally necessary for circt-synth to skip verification code. Sometimes verification code has constructs that are hard to synthesize such as 32bit div/mod. Also it saves a lot of resources when targeting sub hierarchy. |
Add a new pass that allows running passes under hierarchy. This is useful when we want to run synthesis passes only on real designs.
This implementation is based on MLIR's upstream CompositePass and Inliner utilities. The pass takes a pipeline string and runs it on modules in the design hierarchy. It supports configurable options including the pipeline to run under hierarchy, the name of the top-level module, and whether to include bound instances in the hierarchy traversal.
The implementation updates circt-synth tool with the required library dependencies and necessary dialect and pass headers.