Support for creating chisel annotations that are consumed by firrtl (#393)

* Support for creating chisel annotations that are consumed by firrtl
Update annotation serialization in Driver
Add DiamondAnnotation Spec that illustrates how to do simple annotations
frontEnd must have dependency on firrtl
Add annotation method to Module
Circuit has extra optional parameter that is Seq of Annotations
In Builder add annotation buffer to DynamicContext to store annotations created in modules
Added explicit types on naming api methods to avoid type confusion
Because some names are not available until elaboration create intermediate ChiselAnnotation that
gets turned into a firrtl Annotation after elaboration
In execute pass firrtl text and annotation to firrtl are now passed in through optionManager, though
intermediate file .fir and .anno files are still created for inspection and/or later use

* Somehow missed ChiselAnnotation

* fixes for Jack's review of PR

1 files changed, 30 insertions, 0 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/ChiselAnnotation.scala b/chiselFrontend/src/main/scala/chisel3/core/ChiselAnnotation.scala
new file mode 100644
index 00000000..73573bb1
--- /dev/null
+++ b/chiselFrontend/src/main/scala/chisel3/core/ChiselAnnotation.scala
@@ -0,0 +1,30 @@
+// See LICENSE for license details.
+
+package chisel3.core
+
+import chisel3.internal.InstanceId
+import firrtl.Transform
+import firrtl.annotations.{Annotation, CircuitName, ComponentName, ModuleName}
+
+/**
+  * This is a stand-in for the firrtl.Annotations.Annotation because at the time this annotation
+  * is created the component cannot be resolved, into a targetString.  Resolution can only
+  * happen after the circuit is elaborated
+  * @param component       A chisel thingy to be annotated, could be module, wire, reg, etc.
+  * @param transformClass  A fully-qualified class name of the transformation pass
+  * @param value           A string value to be used by the transformation pass
+  */
+case class ChiselAnnotation(component: InstanceId, transformClass: Class[_ <: Transform], value: String) {
+  def toFirrtl: Annotation = {
+    val circuitName = CircuitName(component.pathName.split("""\.""").head)
+    component match {
+      case m: Module =>
+        Annotation(
+          ModuleName(m.name, circuitName), transformClass, value)
+      case _ =>
+        Annotation(
+          ComponentName(
+            component.instanceName, ModuleName(component.parentModName, circuitName)), transformClass, value)
+    }
+  }
+}