Add assumeNoDirectionIsOutput.

2 files changed, 15 insertions, 2 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/MonoConnect.scala b/chiselFrontend/src/main/scala/chisel3/core/MonoConnect.scala
index 4ba921fa..74373e22 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/MonoConnect.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/MonoConnect.scala
@@ -133,7 +133,13 @@ object MonoConnect {
         case (None,         Some(Input))  => issueConnect(sink, source)
         case (Some(Output), Some(Output)) => issueConnect(sink, source)
         case (Some(Output), Some(Input))  => issueConnect(sink, source)
-        case (_,            None) => throw UnreadableSourceException
+        case (_,            None) => {
+          if (compileOptions.assumeNoDirectionIsOutput) {
+            issueConnect(sink, source)
+          } else {
+            throw UnreadableSourceException
+          }
+        }
         case (Some(Input),  Some(Output)) if (compileOptions.tryConnectionsSwapped) => issueConnect(source, sink)
         case (Some(Input),  _)    => throw UnwritableSinkException
       }
@@ -165,7 +171,13 @@ object MonoConnect {
         case (Some(Input),  Some(Input))  => issueConnect(sink, source)
         case (Some(Input),  Some(Output)) => issueConnect(sink, source)
         case (Some(Output), _)            => throw UnwritableSinkException
-        case (_,            None)         => throw UnreadableSourceException
+        case (_,            None) => {
+          if (compileOptions.assumeNoDirectionIsOutput) {
+            issueConnect(sink, source)
+          } else {
+            throw UnreadableSourceException
+          }
+        }
         case (None,         _)            => throw UnwritableSinkException
       }
     }
diff --git a/chiselFrontend/src/main/scala/chisel3/internal/CompileOptions.scala b/chiselFrontend/src/main/scala/chisel3/internal/CompileOptions.scala
index e040201b..912184fb 100644
--- a/chiselFrontend/src/main/scala/chisel3/internal/CompileOptions.scala
+++ b/chiselFrontend/src/main/scala/chisel3/internal/CompileOptions.scala
@@ -19,4 +19,5 @@ class CompileOptions(optionsMap: Map[String, String]) {
   val portDeterminesDirection: Boolean = optionsMap.getOrElse("portDeterminesDirection", looseDefault).toBoolean
   val tryConnectionsSwapped: Boolean = optionsMap.getOrElse("tryConnectionsSwapped", looseDefault).toBoolean
   val assumeLHSIsOutput: Boolean = optionsMap.getOrElse("assumeLHSIsOutput", looseDefault).toBoolean
+  val assumeNoDirectionIsOutput: Boolean = optionsMap.getOrElse("assumeNoDirectionIsOutput", looseDefault).toBoolean
 }