lesson2
AnalyzeCircuit Transform
Ledger tracks firrtl.ir.Circuit statistics
Ledger tracks firrtl.ir.Circuit statistics
In this lesson, we want to calculate the number of muxes, not just in a module, but also in any instances it has of other modules, etc.
To do this, we need to update our Ledger class to keep track of this module instance information
AnalyzeCircuit Transform
Walks firrtl.ir.Circuit, and records the number of muxes and instances it finds, per module.
While the Firrtl parser emits a bare form of the IR (located in firrtl.ir._), it is often useful to have more information in these case classes. To do this, the Firrtl compiler has mirror "working" classes for the following IR nodes (which contain additional fields):
Take a look at ToWorkginIR in src/main/scala/firrtl/passes/Passes.scala to see how Firrtl IR nodes are replaced with working IR nodes.
Future lessons will explain the WIR's additional fields. For now, it is enough to know that the transform firrtl.ResolveAndCheck populates these fields, and checks the legality of the circuit. If your transform is creating new WIR nodes, use the following "unknown" values in the WIR node, and then call firrtl.ResolveAndCheck at the end of your transform:
The following firrtl.CircuitForms require WIR instead of IR nodes:
See the following links for more detailed explanations: IR vs Working IR