// SPDX-License-Identifier: Apache-2.0

package firrtl.passes
package clocklist

import firrtl._
import firrtl.ir._
import Utils._
import Mappers._

/** Remove all statements and ports (except instances/whens/blocks) whose
  *  expressions do not relate to ground types.
  */
object RemoveAllButClocks extends Pass {
  def onStmt(s: Statement): Statement = (s.map(onStmt)) match {
    case DefWire(i, n, ClockType)                       => s
    case DefNode(i, n, value) if value.tpe == ClockType => s
    case Connect(i, l, r) if l.tpe == ClockType         => s
    case sx: DefInstance   => sx
    case sx: Block         => sx
    case sx: Conditionally => sx
    case _ => EmptyStmt
  }
  def onModule(m: DefModule): DefModule = m match {
    case Module(i, n, ps, b)        => Module(i, n, ps.filter(_.tpe == ClockType), squashEmpty(onStmt(b)))
    case ExtModule(i, n, ps, dn, p) => ExtModule(i, n, ps.filter(_.tpe == ClockType), dn, p)
  }
  def run(c: Circuit): Circuit = c.copy(modules = c.modules.map(onModule))
}