Dont try to instantiate firrtl.Transform from Annotation

Also make transform instantiation deterministic

1 files changed, 10 insertions, 4 deletions

diff --git a/src/main/scala/chisel3/Driver.scala b/src/main/scala/chisel3/Driver.scala
index 8a2256df..f3ba6534 100644
--- a/src/main/scala/chisel3/Driver.scala
+++ b/src/main/scala/chisel3/Driver.scala
@@ -146,10 +146,16 @@ object Driver extends BackendCompilationUtilities {
     af.write(circuit.annotations.toArray.toYaml.prettyPrint)
     af.close()
 
-    /* create custom transforms by finding the set of transform classes associated with annotations
-     * then instantiate them into actual transforms
-     */
-    val transforms = circuit.annotations.map(_.transform).toSet.map { transformClass: Class[_ <: Transform] =>
+    /** Find the set of transform classes associated with annotations then
+      * instantiate an instance of each transform
+      * @note Annotations targeting firrtl.Transform will not result in any
+      *   transform being instantiated
+      */
+    val transforms = circuit.annotations
+                            .map(_.transform)
+                            .distinct
+                            .filterNot(_ == classOf[firrtl.Transform])
+                            .map { transformClass: Class[_ <: Transform] =>
       transformClass.newInstance()
     }
     /* This passes the firrtl source and annotations directly to firrtl */