From 3bea6167159737b379f37031c3beef27337be06d Mon Sep 17 00:00:00 2001
From: Jack Koenig
Date: Fri, 12 Mar 2021 15:33:58 -0800
Subject: [plugin] Disable BundleComponent by default, add option to enable

---
 .../chisel3/internal/plugin/BundleComponent.scala   | 15 +++++++++++++--
 .../chisel3/internal/plugin/ChiselPlugin.scala      | 21 ++++++++++++++++++++-
 2 files changed, 33 insertions(+), 3 deletions(-)

(limited to 'plugin/src/main')

diff --git a/plugin/src/main/scala-2.12/chisel3/internal/plugin/BundleComponent.scala b/plugin/src/main/scala-2.12/chisel3/internal/plugin/BundleComponent.scala
index 0711e08c..96851e95 100644
--- a/plugin/src/main/scala-2.12/chisel3/internal/plugin/BundleComponent.scala
+++ b/plugin/src/main/scala-2.12/chisel3/internal/plugin/BundleComponent.scala
@@ -10,7 +10,9 @@ import scala.tools.nsc.symtab.Flags
 import scala.tools.nsc.transform.TypingTransformers
 
 // TODO This component could also implement val elements in Bundles
-private[plugin] class BundleComponent(val global: Global) extends PluginComponent with TypingTransformers {
+private[plugin] class BundleComponent(val global: Global, arguments: ChiselPluginArguments)
+    extends PluginComponent
+    with TypingTransformers {
   import global._
 
   val phaseName: String = "chiselbundlephase"
@@ -23,8 +25,17 @@ private[plugin] class BundleComponent(val global: Global) extends PluginComponen
       // This plugin doesn't work on Scala 2.11 nor Scala 3. Rather than complicate the sbt build flow,
       // instead we just check the version and if its an early Scala version, the plugin does nothing
       val scalaVersion = scala.util.Properties.versionNumberString.split('.')
-      if (scalaVersion(0).toInt == 2 && scalaVersion(1).toInt >= 12) {
+      val scalaVersionOk = scalaVersion(0).toInt == 2 && scalaVersion(1).toInt >= 12
+      if (scalaVersionOk && arguments.useBundlePlugin) {
         unit.body = new MyTypingTransformer(unit).transform(unit.body)
+      } else {
+        val reason = if (!scalaVersionOk) {
+          s"invalid Scala version '${scala.util.Properties.versionNumberString}'"
+        } else {
+          s"not enabled via '${arguments.useBundlePluginFullOpt}'"
+        }
+        // Enable this with scalacOption '-Ylog:chiselbundlephase'
+        global.log(s"Skipping BundleComponent on account of $reason.")
       }
     }
   }
diff --git a/plugin/src/main/scala-2.12/chisel3/internal/plugin/ChiselPlugin.scala b/plugin/src/main/scala-2.12/chisel3/internal/plugin/ChiselPlugin.scala
index d5eb21cc..a0651e1d 100644
--- a/plugin/src/main/scala-2.12/chisel3/internal/plugin/ChiselPlugin.scala
+++ b/plugin/src/main/scala-2.12/chisel3/internal/plugin/ChiselPlugin.scala
@@ -6,13 +6,32 @@ import scala.tools.nsc
 import nsc.Global
 import nsc.plugins.{Plugin, PluginComponent}
 
+private[plugin] case class ChiselPluginArguments(var useBundlePlugin: Boolean = false) {
+  def useBundlePluginOpt = "useBundlePlugin"
+  def useBundlePluginFullOpt = s"-P:chiselplugin:$useBundlePluginOpt"
+}
+
 // The plugin to be run by the Scala compiler during compilation of Chisel code
 class ChiselPlugin(val global: Global) extends Plugin {
   val name = "chiselplugin"
   val description = "Plugin for Chisel 3 Hardware Description Language"
+  private val arguments = ChiselPluginArguments()
   val components: List[PluginComponent] = List[PluginComponent](
     new ChiselComponent(global),
-    new BundleComponent(global)
+    new BundleComponent(global, arguments)
   )
+
+  override def init(options: List[String], error: String => Unit): Boolean = {
+    for (option <- options) {
+      if (option == arguments.useBundlePluginOpt) {
+        arguments.useBundlePlugin = true
+      } else {
+        error(s"Option not understood: '$option'")
+      }
+    }
+    true
+  }
+
+
 }
 
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