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

2 files changed, 15 insertions, 0 deletions

diff --git a/src/main/scala/chisel3/Driver.scala b/src/main/scala/chisel3/Driver.scala
index ab51ad25..646702c3 100644
--- a/src/main/scala/chisel3/Driver.scala
+++ b/src/main/scala/chisel3/Driver.scala
@@ -6,10 +6,13 @@ import chisel3.internal.firrtl.Emitter
 
 import scala.sys.process._
 import java.io._
+import net.jcazevedo.moultingyaml._
 
 import internal.firrtl._
 import firrtl._
 
+import _root_.firrtl.annotations.AnnotationYamlProtocol._
+
 /**
   * The Driver provides methods to invoke the chisel3 compiler and the firrtl compiler.
   * By default firrtl is automatically run after chisel.  an [[ExecutionOptionsManager]]
@@ -239,6 +242,15 @@ object Driver extends BackendCompilationUtilities {
     w.write(firrtlString)
     w.close()
 
+    val annotationFile = new File(optionsManager.getBuildFileName("anno"))
+    val af = new FileWriter(annotationFile)
+    af.write(circuit.annotations.toArray.toYaml.prettyPrint)
+    af.close()
+
+    /* This passes the firrtl source and annotations directly to firrtl */
+    optionsManager.firrtlOptions = optionsManager.firrtlOptions.copy(
+      firrtlSource = Some(firrtlString), annotations = circuit.annotations.toList)
+
     val firrtlExecutionResult = if(chiselOptions.runFirrtlCompiler) {
       Some(firrtl.Driver.execute(optionsManager))
     }
diff --git a/src/main/scala/chisel3/package.scala b/src/main/scala/chisel3/package.scala
index e4e64b89..25d3ec3a 100644
--- a/src/main/scala/chisel3/package.scala
+++ b/src/main/scala/chisel3/package.scala
@@ -32,6 +32,9 @@ package object chisel3 {    // scalastyle:ignore package.object.name
   type Element = chisel3.core.Element
   type Bits = chisel3.core.Bits
 
+  type ChiselAnnotation = chisel3.core.ChiselAnnotation
+  val ChiselAnnotation = chisel3.core.ChiselAnnotation
+
   // Some possible regex replacements for the literal specifier deprecation:
   // (note: these are not guaranteed to handle all edge cases! check all replacements!)
   // Bool\((true|false)\)