1 files changed, 46 insertions, 0 deletions
diff --git a/src/main/scala/firrtl/annotations/TargetUtils.scala b/src/main/scala/firrtl/annotations/TargetUtils.scala
new file mode 100644
index 00000000..164c430b
--- /dev/null
+++ b/src/main/scala/firrtl/annotations/TargetUtils.scala
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package firrtl.annotations
+
+import firrtl._
+import firrtl.analyses.InstanceKeyGraph
+import firrtl.analyses.InstanceKeyGraph.InstanceKey
+import firrtl.annotations.TargetToken._
+
+object TargetUtils {
+
+  /** Turns an instance path into a corresponding [[IsModule]]
+    *
+    * @note First InstanceKey is treated as the [[CircuitTarget]]
+    * @param path Instance path
+    * @param start Module in instance path to be starting [[ModuleTarget]]
+    * @return [[IsModule]] corresponding to Instance path
+    */
+  def instKeyPathToTarget(path: Seq[InstanceKey], start: Option[String] = None): IsModule = {
+    val head = path.head
+    val startx = start.getOrElse(head.module)
+    val top: IsModule = CircuitTarget(head.module).module(startx) // ~Top|Start
+    val pathx = path.dropWhile(_.module != startx)
+    if (pathx.isEmpty) top
+    else pathx.tail.foldLeft(top) { case (acc, key) => acc.instOf(key.name, key.module) }
+  }
+
+  /** Calculates all [[InstanceTarget]]s that refer to the given [[IsModule]]
+    *
+    * {{{
+    * ~Top|Top/a:A/b:B/c:C unfolds to:
+    * * ~Top|Top/a:A/b:B/c:C
+    * * ~Top|A/b:B/c:C
+    * * ~Top|B/c:C
+    * }}}
+    * @note [[ModuleTarget]] arguments return an empty Iterable
+    */
+  def unfoldInstanceTargets(ismod: IsModule): Iterable[InstanceTarget] = {
+    // concretely use List which is fast in practice
+    def rec(im: IsModule): List[InstanceTarget] = im match {
+      case inst: InstanceTarget => inst :: rec(inst.stripHierarchy(1))
+      case _ => Nil
+    }
+    rec(ismod)
+  }
+}