Restore return type of BaseModule.toTarget to ModuleTarget (#2117)

Definition/Instance introduced the need for representing the targets of
instances as InstanceTargets. This original implementation changed the
return type of BaseModule.toTarget to express this need. This is a
backwards incompatible change that is actually unnecessary because it is
impossible for users to get references to the internal InstanceClone
objects, instead only accessing such modules via Instance[_] wrappers
and cloned Data. We restored the old API by adding a new internal method
"getTarget" which will give the correct targets for InstanceClones while
maintaining the API of BaseModule.toTarget.

2 files changed, 10 insertions, 9 deletions

diff --git a/core/src/main/scala/chisel3/experimental/hierarchy/Definition.scala b/core/src/main/scala/chisel3/experimental/hierarchy/Definition.scala
index 2e917dfa..0cc3d131 100644
--- a/core/src/main/scala/chisel3/experimental/hierarchy/Definition.scala
+++ b/core/src/main/scala/chisel3/experimental/hierarchy/Definition.scala
@@ -3,13 +3,14 @@
 package chisel3.experimental.hierarchy
 
 import scala.language.experimental.macros
-
 import chisel3._
+
 import scala.collection.mutable.HashMap
 import chisel3.internal.{Builder, DynamicContext}
 import chisel3.internal.sourceinfo.{DefinitionTransform, DefinitionWrapTransform, SourceInfo}
 import chisel3.experimental.BaseModule
 import chisel3.internal.BaseModule.IsClone
+import firrtl.annotations.{IsModule, ModuleTarget}
 
 /** User-facing Definition type.
   * Represents a definition of an object of type [[A]] which are marked as @instantiable 
@@ -64,12 +65,12 @@ object Definition extends SourceInfoDoc {
     /** If this is an instance of a Module, returns the toTarget of this instance
       * @return target of this instance
       */
-    def toTarget = d.proto.toTarget
+    def toTarget: ModuleTarget = d.proto.toTarget
 
     /** If this is an instance of a Module, returns the toAbsoluteTarget of this instance
       * @return absoluteTarget of this instance
       */
-    def toAbsoluteTarget = d.proto.toAbsoluteTarget
+    def toAbsoluteTarget: IsModule = d.proto.toAbsoluteTarget
   }
   /** A construction method to build a Definition of a Module
     *
diff --git a/core/src/main/scala/chisel3/experimental/hierarchy/Instance.scala b/core/src/main/scala/chisel3/experimental/hierarchy/Instance.scala
index aec42da3..9b17bfce 100644
--- a/core/src/main/scala/chisel3/experimental/hierarchy/Instance.scala
+++ b/core/src/main/scala/chisel3/experimental/hierarchy/Instance.scala
@@ -4,11 +4,11 @@ package chisel3.experimental.hierarchy
 
 import scala.collection.mutable.{ArrayBuffer, HashMap}
 import scala.language.experimental.macros
-
 import chisel3._
-import chisel3.internal.BaseModule.{ModuleClone, IsClone, InstantiableClone}
+import chisel3.internal.BaseModule.{InstantiableClone, IsClone, ModuleClone}
 import chisel3.internal.sourceinfo.{InstanceTransform, SourceInfo}
 import chisel3.experimental.BaseModule
+import firrtl.annotations.IsModule
 
 /** User-facing Instance type.
   * Represents a unique instance of type [[A]] which are marked as @instantiable 
@@ -75,15 +75,15 @@ object Instance extends SourceInfoDoc {
     /** If this is an instance of a Module, returns the toTarget of this instance
       * @return target of this instance
       */
-    def toTarget = i.cloned match {
-      case Left(x: BaseModule) => x.toTarget
-      case Right(x: IsClone[_] with BaseModule) => x.toTarget
+    def toTarget: IsModule = i.cloned match {
+      case Left(x: BaseModule) => x.getTarget
+      case Right(x: IsClone[_] with BaseModule) => x.getTarget
     }
 
     /** If this is an instance of a Module, returns the toAbsoluteTarget of this instance
       * @return absoluteTarget of this instance
       */
-    def toAbsoluteTarget = i.cloned match {
+    def toAbsoluteTarget: IsModule = i.cloned match {
       case Left(x) => x.toAbsoluteTarget
       case Right(x: IsClone[_] with BaseModule) => x.toAbsoluteTarget
     }