diff --git a/build.sbt b/build.sbt
index 6c2033327..a2d2fb10a 100644
--- a/build.sbt
+++ b/build.sbt
@@ -77,6 +77,11 @@ lazy val runtime = crossProject.crossType(CrossType.Full).in(file("scalapb-runti
     libraryDependencies ++= Seq(
       "com.trueaccord.scalapb" %%% "protobuf-runtime-scala" % "0.1.6"
     ),
+    scalacOptions += {
+      val a = (baseDirectory in LocalRootProject).value.toURI.toString
+      val g = "https://raw.githubusercontent.com/trueaccord/ScalaPB/" + sys.process.Process("git rev-parse HEAD").lines_!.head
+      s"-P:scalajs:mapSourceURI:$a->$g/"
+    },
     unmanagedResourceDirectories in Compile += baseDirectory.value / "../../third_party"
   )