Add InstanceGraph helpers: reachable/unreachable

Adds new APIs for querying sets of modules in an InstanceGraph:

  - modules: the set of all modules
  - reachableModules: set of modules reachable from the main/top
  - unreachableModules: set of modules not reachable from the main/top

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/main/scala/firrtl/analyses/InstanceGraph.scala b/src/main/scala/firrtl/analyses/InstanceGraph.scala
index b8b40065..7b60b110 100644
--- a/src/main/scala/firrtl/analyses/InstanceGraph.scala
+++ b/src/main/scala/firrtl/analyses/InstanceGraph.scala
@@ -140,6 +140,16 @@ class InstanceGraph(c: Circuit) {
   def getChildrenInstanceMap: collection.Map[OfModule, collection.Map[Instance, OfModule]] =
     childInstances.map(kv => kv._1.OfModule -> asOrderedMap(kv._2, (i: WDefInstance) => i.toTokens))
 
+  /** The set of all modules in the circuit */
+  lazy val modules: collection.Set[OfModule] = graph.getVertices.map(_.OfModule)
+
+  /** The set of all modules in the circuit reachable from the top module */
+  lazy val reachableModules: collection.Set[OfModule] =
+    mutable.LinkedHashSet(trueTopInstance.OfModule) ++ graph.reachableFrom(trueTopInstance).map(_.OfModule)
+
+  /** The set of all modules *not* reachable in the circuit */
+  lazy val unreachableModules: collection.Set[OfModule] = modules diff reachableModules
+
 }
 
 object InstanceGraph {