Support Singleton Dependencies (#1275)

This makes a change to the Dependency API that breaks chisel3. This
needs to [skip chisel tests], but is fixed with
https://github.com/freechipsproject/chisel3/pull/1270.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala b/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala
index bb2a8cd6..4a638393 100644
--- a/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala
+++ b/src/main/scala/firrtl/options/phases/WriteOutputAnnotations.scala
@@ -4,14 +4,23 @@ package firrtl.options.phases
 
 import firrtl.AnnotationSeq
 import firrtl.annotations.{DeletedAnnotation, JsonProtocol}
-import firrtl.options.{Phase, StageOptions, Unserializable, Viewer}
+import firrtl.options.{Phase, PreservesAll, StageOptions, Unserializable, Viewer}
+import firrtl.options.Dependency
 
 import java.io.PrintWriter
 
 /** [[firrtl.options.Phase Phase]] that writes an [[AnnotationSeq]] to a file. A file is written if and only if a
   * [[StageOptions]] view has a non-empty [[StageOptions.annotationFileOut annotationFileOut]].
   */
-class WriteOutputAnnotations extends Phase {
+class WriteOutputAnnotations extends Phase with PreservesAll[Phase] {
+
+  override val prerequisites =
+    Seq( Dependency[GetIncludes],
+         Dependency[ConvertLegacyAnnotations],
+         Dependency[AddDefaults],
+         Dependency[Checks] )
+
+  override val dependents = Seq.empty
 
   /** Write the input [[AnnotationSeq]] to a fie. */
   def transform(annotations: AnnotationSeq): AnnotationSeq = {