From ea44af954657f743c45fbc45125e197ac3aadd20 Mon Sep 17 00:00:00 2001
From: mergify[bot]
Date: Sat, 18 Jun 2022 00:08:41 +0000
Subject: Handle varargs constructor arguments in Bundle plugin (#2585) (#2588)

Previously, the plugin would crash with a useless internal error.

(cherry picked from commit 9fcfb252beb9f06d8d1409fe7db9c8b3b6b962ce)

Co-authored-by: Jack Koenig <koenig@sifive.com>---
 .../chisel3/internal/plugin/BundleComponent.scala     |  6 +++++-
 src/test/scala/chiselTests/AutoClonetypeSpec.scala    | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala b/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala
index e3ec0a04..eca3b158 100644
--- a/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala
+++ b/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala
@@ -84,6 +84,8 @@ private[plugin] class BundleComponent(val global: Global, arguments: ChiselPlugi
     def isNullaryMethodNamed(name: String, defdef: DefDef): Boolean =
       defdef.name.decodedName.toString == name && defdef.tparams.isEmpty && defdef.vparamss.isEmpty
 
+    def isVarArgs(sym: Symbol): Boolean = definitions.isRepeatedParamType(sym.tpe)
+
     def getConstructorAndParams(body: List[Tree]): (Option[DefDef], Seq[Symbol]) = {
       val paramAccessors = mutable.ListBuffer[Symbol]()
       var primaryConstructor: Option[DefDef] = None
@@ -134,7 +136,9 @@ private[plugin] class BundleComponent(val global: Global, arguments: ChiselPlugi
               // Make this.<ref>
               val select = gen.mkAttributedSelect(thiz.asInstanceOf[Tree], p)
               // Clone any Data parameters to avoid field aliasing, need full clone to include direction
-              if (isData(vp.symbol)) cloneTypeFull(select.asInstanceOf[Tree]) else select
+              val cloned = if (isData(vp.symbol)) cloneTypeFull(select.asInstanceOf[Tree]) else select
+              // Need to splat varargs
+              if (isVarArgs(vp.symbol)) q"$cloned: _*" else cloned
             })
 
           val tparamList = bundle.tparams.map { t => Ident(t.symbol) }
diff --git a/src/test/scala/chiselTests/AutoClonetypeSpec.scala b/src/test/scala/chiselTests/AutoClonetypeSpec.scala
index 2ab4c800..5d2cd496 100644
--- a/src/test/scala/chiselTests/AutoClonetypeSpec.scala
+++ b/src/test/scala/chiselTests/AutoClonetypeSpec.scala
@@ -381,4 +381,23 @@ class AutoClonetypeSpec extends ChiselFlatSpec with Utils {
     }
     elaborate(new MyModule)
   }
+
+  it should "support Bundles with vararg arguments" in {
+    // Without the fix, this doesn't even compile
+    // Extra parameter lists to make this a complex test case
+    class VarArgsBundle(x: Int)(y: Int, widths: Int*) extends Bundle {
+      def mkField(idx: Int): Option[UInt] =
+        (x +: y +: widths).lift(idx).map(w => UInt(w.W))
+      val foo = mkField(0)
+      val bar = mkField(1)
+      val fizz = mkField(2)
+      val buzz = mkField(3)
+    }
+    class MyModule extends Module {
+      val in = IO(Input(new VarArgsBundle(1)(2, 3, 4)))
+      val out = IO(Output(new VarArgsBundle(1)(2, 3, 4)))
+      out := in
+    }
+    elaborate(new MyModule)
+  }
 }
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