Adjustments to the build structure (see below)

All 'addon' subprojects now have their sources aggregated into the addons subproject. This is done via a source copy (so that sbt will only rebuild sources that actually changed). To prevent caching issues the addons/src directory is CLEARED and then refilled every time addons is compiled. Thus, it is CRUCIAL NO SOURCES ARE MANUALLY ADDED TO addons/src AS THEY WILL BE WIPED BY addons/prepare. Due to sbt source caching, sbt will still be able to tell which sources have changed. (Strangely, sbt would not cache sources in extra unmanaged source directories and thus would always recompile them.) Also, cleaned up project/build.scala a bit to remove some warnings: Added import scala.language/postFixOps (so make! at the bottom no longer errors) and .toURI.toURL (as straight .toURL has been deprecated by the java standard library).

addons/.gitignore

@@ -0,0 +1,2 @@
+src
+target

addons/DO_NOT_ADD_FILES_HERE.README

@@ -0,0 +1,3 @@
+ANY FILES ADDED HERE WILL BE DELETED
+
+The src directory is dynamically refreshed by the rocketchip project as part of the addons/prepare task.

project/build.scala

@@ -1,5 +1,6 @@
 import sbt._
 import Keys._
+import scala.language.postfixOps
 //val extracted: Extracted = Project.extract(state)
 //import extracted._
 
@@ -32,21 +33,29 @@ object BuildSettings extends Build {
   lazy val rocket     = Project("rocket", file("rocket"), settings = buildSettings) dependsOn(uncore)
 
   val baselist = Vector("chisel", "uncore", "rocket", "hardfloat")
-  def show[A](in: Seq[A]) = in.map(_.toString).foldRight("")(_+" "+_)
   def getsubdirs = {
-    val blacklist = (baselist ++ Vector("target", "project"))
+    val blacklist = (baselist ++ Vector("target", "project", "addons"))
     IO.listFiles(file(".")) map (_.toString.split("/").last) filter (f=> !blacklist.contains(f)) filter (f=> !IO.listFiles(file(f+"/src/main/scala")).isEmpty)
   }
-  // def buildsubproj(sproj: String) = Project(sproj, file(sproj), settings = buildSettings).dependsOn(chisel, uncore, rocket, hardfloat)
-  // val subprojs = (getsubprojs map (sproj=>buildsubproj(sproj)))
-  //    unfortunately, creating projects on the fly doesn't seem to quite work in sbt
+  val addonsources = getsubdirs map (f=>s"${f}/src/main/scala") map (f=>file(f))
+  addonsources.foreach(a => println(s"[info] Found addon: " + a.toString.split("/").head))
 
-  val othersources = getsubdirs map (f=>s"${f}/src/main/scala") map (f=>file(f))
-  val addOtherFiles = Seq (
-    unmanagedSourceDirectories in Compile ++= othersources.toSeq
-  ) // so instead, for dynamically expanding projects, just compile them all at once with rocket chip
+  val prepareTask = TaskKey[Unit]("prepare","Remove old sources and copy over new ones to addon/src")
+  def prepareTaskImpl = {
+    import IO._
+    delete(file("addons/src"))
+    createDirectory(file("addons/src/main/scala"))
+    addonsources.foreach(as => {
+      val addonname = as.toString.split("/").head
+      copyDirectory(as, file("addons/src/main/scala/"+addonname))
+    })
+  }
   
-  lazy val rocketchip = Project("rocketchip", file("."), settings = buildSettings ++ chipSettings ++ addOtherFiles).dependsOn(chisel, hardfloat, uncore, rocket)
+  lazy val addons     = Project("addons", file("addons"), settings = buildSettings ++ Seq(
+    prepareTask := prepareTaskImpl,
+    (compile in Compile) <<= (compile in Compile) dependsOn (prepareTask)
+  )) dependsOn(chisel, hardfloat, uncore, rocket)
+  lazy val rocketchip = Project("rocketchip", file("."), settings = buildSettings ++ chipSettings).dependsOn(chisel, uncore, rocket, addons)
 
   val elaborateTask = InputKey[Unit]("elaborate", "convert chisel components into backend source code")
   val makeTask = InputKey[Unit]("make", "trigger backend-specific makefile command")
@@ -57,7 +66,7 @@ object BuildSettings extends Build {
      val projectName = pr.id
      val packageName = projectName //TODO: valid convention?
      val componentName = args(0)
-     val classLoader = new java.net.URLClassLoader(cp.map(_.data.toURL).toArray, cp.getClass.getClassLoader)
+     val classLoader = new java.net.URLClassLoader(cp.map(_.data.toURI.toURL).toArray, cp.getClass.getClassLoader)
      val chiselMainClass = classLoader.loadClass("Chisel.chiselMain$")
      val chiselMainObject = chiselMainClass.getDeclaredFields.head.get(null)
      val chiselMain = chiselMainClass.getMethod("run", classOf[Array[String]], classOf[Function0[_]])