Stop reporting exceptions in custom transformations as internal errors (#867)

Instead, just forward the exception

2 files changed, 22 insertions, 1 deletions

diff --git a/src/main/scala/firrtl/Compiler.scala b/src/main/scala/firrtl/Compiler.scala
index 87662800..1ef35891 100644
--- a/src/main/scala/firrtl/Compiler.scala
+++ b/src/main/scala/firrtl/Compiler.scala
@@ -295,6 +295,9 @@ trait Emitter extends Transform {
   def emit(state: CircuitState, writer: Writer): Unit
 }
 
+/** Wraps exceptions from CustomTransforms so they can be reported appropriately */
+case class CustomTransformException(cause: Throwable) extends Exception("", cause)
+
 object CompilerUtils extends LazyLogging {
   /** Generates a sequence of [[Transform]]s to lower a Firrtl circuit
     *
@@ -427,6 +430,15 @@ trait Compiler extends LazyLogging {
     compile(state.copy(annotations = emitAnno +: state.annotations), customTransforms)
   }
 
+  private def isCustomTransform(xform: Transform): Boolean = {
+    def getTopPackage(pack: java.lang.Package): java.lang.Package =
+      Package.getPackage(pack.getName.split('.').head)
+    // We use the top package of the Driver to get the top firrtl package
+    Option(xform.getClass.getPackage).map { p =>
+      getTopPackage(p) != firrtl.Driver.getClass.getPackage
+    }.getOrElse(true)
+  }
+
   /** Perform compilation
     *
     * Emission will only be performed if [[EmitAnnotation]]s are present
@@ -440,7 +452,14 @@ trait Compiler extends LazyLogging {
     val allTransforms = CompilerUtils.mergeTransforms(transforms, customTransforms) :+ emitter
 
     val (timeMillis, finalState) = Utils.time {
-      allTransforms.foldLeft(state) { (in, xform) => xform.runTransform(in) }
+      allTransforms.foldLeft(state) { (in, xform) =>
+        try {
+          xform.runTransform(in)
+        } catch {
+          // Wrap exceptions from custom transforms so they are reported as such
+          case e: Exception if isCustomTransform(xform) => throw CustomTransformException(e)
+        }
+      }
     }
 
     logger.error(f"Total FIRRTL Compile Time: $timeMillis%.1f ms")
diff --git a/src/main/scala/firrtl/Driver.scala b/src/main/scala/firrtl/Driver.scala
index 47841cec..c277e120 100644
--- a/src/main/scala/firrtl/Driver.scala
+++ b/src/main/scala/firrtl/Driver.scala
@@ -248,6 +248,8 @@ object Driver {
         case p: PassException    => throw p
         case p: PassExceptions   => throw p
         case p: FIRRTLException  => throw p
+        // Propagate exceptions from custom transforms
+        case CustomTransformException(cause) => throw cause
         // Treat remaining exceptions as internal errors.
         case e: Exception => throwInternalError(exception = Some(e))
       }