Fix aop.Select behavior for CloneModuleAsRecord (backport #1993)

core/src/main/scala/chisel3/Module.scala

@@ -136,6 +136,8 @@ package internal {
       private[BaseModule] var _portsRecord: Record = _
       // Don't generate a component, but point to the one for the cloned Module
       private[chisel3] def generateComponent(): Option[Component] = {
+        require(!_closed, "Can't generate module more than once")
+        _closed = true
         _component = _proto._component
         None
       }

src/main/scala/chisel3/aop/Select.scala

@@ -6,6 +6,7 @@ import chisel3._
 import chisel3.experimental.{BaseModule, FixedPoint}
 import chisel3.internal.HasId
 import chisel3.internal.firrtl._
+import chisel3.internal.BaseModule.ModuleClone
 import firrtl.annotations.ReferenceTarget
 
 import scala.collection.mutable
@@ -81,8 +82,12 @@ object Select {
   def instances(module: BaseModule): Seq[BaseModule] = {
     check(module)
     module._component.get match {
-      case d: DefModule => d.commands.collect {
-        case i: DefInstance => i.id
+      case d: DefModule => d.commands.flatMap {
+        case i: DefInstance => i.id match {
+          case _: ModuleClone => None
+          case other          => Some(other)
+        }
+        case _ => None
       }
       case other => Nil
     }

src/test/scala/chiselTests/aop/SelectSpec.scala

@@ -153,5 +153,31 @@ class SelectSpec extends ChiselFlatSpec {
     assert(bbs.size == 1)
   }
 
+  "CloneModuleAsRecord" should "NOT show up in Select aspects" in {
+    import chisel3.experimental.CloneModuleAsRecord
+    class Child extends RawModule {
+      val in = IO(Input(UInt(8.W)))
+      val out = IO(Output(UInt(8.W)))
+      out := in
+    }
+    class Top extends MultiIOModule {
+      val in = IO(Input(UInt(8.W)))
+      val out = IO(Output(UInt(8.W)))
+      val inst0 = Module(new Child)
+      val inst1 = CloneModuleAsRecord(inst0)
+      inst0.in := in
+      inst1("in") := inst0.out
+      out := inst1("out")
+    }
+    val top = ChiselGeneratorAnnotation(() => {
+      new Top()
+    }).elaborate
+      .collectFirst { case DesignAnnotation(design: Top) => design }
+      .get
+    Select.collectDeep(top) { case x => x } should equal (Seq(top, top.inst0))
+    Select.getDeep(top)(x => Seq(x)) should equal (Seq(top, top.inst0))
+    Select.instances(top) should equal (Seq(top.inst0))
+  }
+
 }