Improve MultiInfo emission, add apply that squashes NoInfo

1 files changed, 15 insertions, 2 deletions

diff --git a/src/main/scala/firrtl/ir/IR.scala b/src/main/scala/firrtl/ir/IR.scala
index 090ad8ec..a3ad4231 100644
--- a/src/main/scala/firrtl/ir/IR.scala
+++ b/src/main/scala/firrtl/ir/IR.scala
@@ -29,10 +29,23 @@ case class MultiInfo(infos: Seq[Info]) extends Info {
     case MultiInfo(seq) => seq flatMap collectStringLits
     case NoInfo => Seq.empty
   }
-  override def toString: String =
-    collectStringLits(this).map(_.serialize).mkString(" @[", " ", "]")
+  override def toString: String = {
+    val parts = collectStringLits(this)
+    if (parts.nonEmpty) parts.map(_.serialize).mkString(" @[", " ", "]")
+    else ""
+  }
   def ++(that: Info): Info = MultiInfo(Seq(this, that))
 }
+object MultiInfo {
+  def apply(infos: Info*) = {
+    val infosx = infos.filterNot(_ == NoInfo)
+    infosx.size match {
+      case 0 => NoInfo
+      case 1 => infosx.head
+      case _ => new MultiInfo(infosx)
+    }
+  }
+}
 
 trait HasName {
   val name: String