Add chisel3.stage.phases.MaybeFirrtlStage

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

1 files changed, 19 insertions, 0 deletions

diff --git a/src/main/scala/chisel3/stage/phases/MaybeFirrtlStage.scala b/src/main/scala/chisel3/stage/phases/MaybeFirrtlStage.scala
new file mode 100644
index 00000000..f830c182
--- /dev/null
+++ b/src/main/scala/chisel3/stage/phases/MaybeFirrtlStage.scala
@@ -0,0 +1,19 @@
+// See LICENSE for license details.
+
+package chisel3.stage.phases
+
+import chisel3.stage.NoRunFirrtlCompilerAnnotation
+
+import firrtl.AnnotationSeq
+import firrtl.options.Phase
+import firrtl.stage.FirrtlStage
+
+/** Run [[firrtl.stage.FirrtlStage]] if a [[chisel3.stage.NoRunFirrtlCompilerAnnotation]] is not present.
+  */
+class MaybeFirrtlStage extends Phase {
+
+  def transform(annotations: AnnotationSeq): AnnotationSeq = annotations
+    .collectFirst { case NoRunFirrtlCompilerAnnotation => annotations }
+    .getOrElse    { (new FirrtlStage).transform(annotations)          }
+
+}