1 files changed, 50 insertions, 1 deletions
diff --git a/build.sbt b/build.sbt
index ea0c0a15..74406b2b 100644
--- a/build.sbt
+++ b/build.sbt
@@ -125,6 +125,54 @@ lazy val chiselSettings = Seq (
   }
 )
 
+autoCompilerPlugins := true
+
+// Plugin must be fully cross-versioned (published for Scala minor version)
+// The plugin only works in Scala 2.12+
+lazy val pluginScalaVersions = Seq(
+  "2.11.12", // Only to support chisel3 cross building for 2.11, plugin does nothing in 2.11
+  // scalamacros paradise version used is not published for 2.12.0 and 2.12.1
+  "2.12.2",
+  "2.12.3",
+  "2.12.4",
+  "2.12.5",
+  "2.12.6",
+  "2.12.7",
+  "2.12.8",
+  "2.12.9",
+  "2.12.10",
+  "2.12.11"
+)
+
+lazy val plugin = (project in file("plugin")).
+  settings(name := "chisel3-plugin").
+  settings(commonSettings: _*).
+  settings(publishSettings: _*).
+  settings(
+    libraryDependencies += "org.scala-lang" % "scala-compiler" % scalaVersion.value,
+    scalacOptions += "-Xfatal-warnings",
+    crossScalaVersions := pluginScalaVersions,
+    // Must be published for Scala minor version
+    crossVersion := CrossVersion.full,
+    crossTarget := {
+      // workaround for https://github.com/sbt/sbt/issues/5097
+      target.value / s"scala-${scalaVersion.value}"
+    },
+    // Only publish for Scala 2.12
+    publish / skip := !scalaVersion.value.startsWith("2.12")
+  )
+
+lazy val usePluginSettings = Seq(
+  scalacOptions in Compile ++= {
+    val jar = (plugin / Compile / Keys.`package`).value
+    val addPlugin = "-Xplugin:" + jar.getAbsolutePath
+    // add plugin timestamp to compiler options to trigger recompile of
+    // main after editing the plugin. (Otherwise a 'clean' is needed.)
+    val dummy = "-Jdummy=" + jar.lastModified
+    Seq(addPlugin, dummy)
+  }
+)
+
 lazy val macros = (project in file("macros")).
   settings(name := "chisel3-macros").
   settings(commonSettings: _*).
@@ -162,9 +210,10 @@ lazy val chisel = (project in file(".")).
   settings(commonSettings: _*).
   settings(chiselSettings: _*).
   settings(publishSettings: _*).
+  settings(usePluginSettings: _*).
   dependsOn(macros).
   dependsOn(core).
-  aggregate(macros, core).
+  aggregate(macros, core, plugin).
   settings(
     scalacOptions in Test ++= Seq("-language:reflectiveCalls"),
     scalacOptions in Compile in doc ++= Seq(