Cleanup aspects (#1359)

* Clean up aspects

* Refactored InjectingAspect with InjectorAspect

* Made AspectLibrary work with objects

* Cleaned up code

* Apply suggestions from code review

* Added tests, removed deprecated newInstance call

* Backed out removal of newInstance as exceptions were different

* Removed trailing commas

1 files changed, 49 insertions, 0 deletions

diff --git a/src/main/scala/chisel3/aop/AspectLibrary.scala b/src/main/scala/chisel3/aop/AspectLibrary.scala
new file mode 100644
index 00000000..e141688e
--- /dev/null
+++ b/src/main/scala/chisel3/aop/AspectLibrary.scala
@@ -0,0 +1,49 @@
+// See LICENSE for license details.
+
+package chisel3.aop
+
+import chisel3.RawModule
+import firrtl.options.{OptionsException, RegisteredLibrary, ShellOption}
+
+/** Enables adding aspects to a design from the commandline, e.g.
+  *  sbt> runMain chisel3.stage.ChiselMain --module <module> --with-aspect <aspect>
+  */
+final class AspectLibrary() extends RegisteredLibrary  {
+  val name = "AspectLibrary"
+
+  import scala.reflect.runtime.universe._
+
+  private def apply(aspectName: String): Aspect[RawModule] = {
+    try {
+      // If a regular class, instantiate, otherwise try as a singleton object
+      try {
+        val x = Class.forName(aspectName).asInstanceOf[Class[_ <: Aspect[RawModule]]]
+        x.newInstance()
+      } catch {
+        case e: InstantiationException =>
+          val rm = runtimeMirror(getClass.getClassLoader)
+          val x = rm.staticModule(aspectName)
+          try {
+            rm.reflectModule(x).instance.asInstanceOf[Aspect[RawModule]]
+          } catch {
+            case _: Exception => throw e
+          }
+      }
+    } catch {
+      case e: ClassNotFoundException =>
+        throw new OptionsException(s"Unable to locate aspect '$aspectName'! (Did you misspell it?)", e)
+      case e: InstantiationException =>
+        throw new OptionsException(
+          s"Unable to create instance of aspect '$aspectName'! (Does this class take parameters?)", e)
+    }
+  }
+
+  val options = Seq(new ShellOption[String](
+    longOption = "with-aspect",
+    toAnnotationSeq = {
+      case aspectName: String => Seq(apply(aspectName))
+    },
+    helpText = "The name/class of an aspect to compile with (must be a class/object without arguments!)",
+    helpValueName = Some("<package>.<aspect>")
+  ))
+}