Scala 2.13 support (#1751)

3 files changed, 390 insertions, 0 deletions

diff --git a/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala b/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala
new file mode 100644
index 00000000..96851e95
--- /dev/null
+++ b/plugin/src/main/scala/chisel3/internal/plugin/BundleComponent.scala
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package chisel3.internal.plugin
+
+import scala.collection.mutable
+import scala.tools.nsc
+import scala.tools.nsc.{Global, Phase}
+import scala.tools.nsc.plugins.PluginComponent
+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, arguments: ChiselPluginArguments)
+    extends PluginComponent
+    with TypingTransformers {
+  import global._
+
+  val phaseName: String = "chiselbundlephase"
+  val runsAfter: List[String] = "typer" :: Nil
+  def newPhase(prev: Phase): Phase = new BundlePhase(prev)
+
+  private class BundlePhase(prev: Phase) extends StdPhase(prev) {
+    override def name: String = phaseName
+    def apply(unit: CompilationUnit): Unit = {
+      // 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('.')
+      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 $reason.")
+      }
+    }
+  }
+
+  private class MyTypingTransformer(unit: CompilationUnit) extends TypingTransformer(unit) {
+
+    def inferType(t: Tree): Type = localTyper.typed(t, nsc.Mode.TYPEmode).tpe
+
+    val bundleTpe = inferType(tq"chisel3.Bundle")
+    val dataTpe = inferType(tq"chisel3.Data")
+
+    // Not cached because it should only be run once per class (thus once per Type)
+    def isBundle(sym: Symbol): Boolean = sym.tpe <:< bundleTpe
+
+    val isDataCache = new mutable.HashMap[Type, Boolean]
+    // Cached because this is run on every argument to every Bundle
+    def isData(sym: Symbol): Boolean = isDataCache.getOrElseUpdate(sym.tpe, sym.tpe <:< dataTpe)
+
+    def cloneTypeFull(tree: Tree): Tree =
+      localTyper.typed(q"chisel3.experimental.DataMirror.internal.chiselTypeClone[${tree.tpe}]($tree)")
+
+    def isNullaryMethodNamed(name: String, defdef: DefDef): Boolean =
+      defdef.name.decodedName.toString == name && defdef.tparams.isEmpty && defdef.vparamss.isEmpty
+
+    def getConstructorAndParams(body: List[Tree]): (Option[DefDef], Seq[Symbol]) = {
+      val paramAccessors = mutable.ListBuffer[Symbol]()
+      var primaryConstructor: Option[DefDef] = None
+      body.foreach {
+        case acc: ValDef if acc.symbol.isParamAccessor =>
+          paramAccessors += acc.symbol
+        case con: DefDef if con.symbol.isPrimaryConstructor =>
+          primaryConstructor = Some(con)
+        case d: DefDef if isNullaryMethodNamed("_cloneTypeImpl", d) =>
+          val msg = "Users cannot override _cloneTypeImpl. Let the compiler plugin generate it. If you must, override cloneType instead."
+          global.globalError(d.pos, msg)
+        case d: DefDef if isNullaryMethodNamed("_usingPlugin", d) =>
+          val msg = "Users cannot override _usingPlugin, it is for the compiler plugin's use only."
+          global.globalError(d.pos, msg)
+        case _ =>
+      }
+      (primaryConstructor, paramAccessors.toList)
+    }
+
+
+    override def transform(tree: Tree): Tree = tree match {
+
+      case bundle: ClassDef if isBundle(bundle.symbol) && !bundle.mods.hasFlag(Flag.ABSTRACT) =>
+
+        // ==================== Generate _cloneTypeImpl ====================
+        val (con, params) = getConstructorAndParams(bundle.impl.body)
+        if (con.isEmpty) {
+          global.reporter.warning(bundle.pos, "Unable to determine primary constructor!")
+          return super.transform(tree)
+        }
+        val constructor = con.get
+
+        val thiz = gen.mkAttributedThis(bundle.symbol)
+
+        // The params have spaces after them (Scalac implementation detail)
+        val paramLookup: String => Symbol = params.map(sym => sym.name.toString.trim -> sym).toMap
+
+        // Create a this.<ref> for each field matching order of constructor arguments
+        // List of Lists because we can have multiple parameter lists
+        val conArgs: List[List[Tree]] =
+          constructor.vparamss.map(_.map { vp =>
+            val p = paramLookup(vp.name.toString)
+            // Make this.<ref>
+            val select = gen.mkAttributedSelect(thiz, p)
+            // Clone any Data parameters to avoid field aliasing, need full clone to include direction
+            if (isData(vp.symbol)) cloneTypeFull(select) else select
+          })
+
+        val ttpe = Ident(bundle.symbol)
+        val neww = localTyper.typed(New(ttpe, conArgs))
+
+        // Create the symbol for the method and have it be associated with the Bundle class
+        val cloneTypeSym =  bundle.symbol.newMethod(TermName("_cloneTypeImpl"), bundle.symbol.pos.focus, Flag.OVERRIDE | Flag.PROTECTED)
+        // Handwritten cloneTypes don't have the Method flag set, unclear if it matters
+        cloneTypeSym.resetFlag(Flags.METHOD)
+        // Need to set the type to chisel3.Bundle for the override to work
+        cloneTypeSym.setInfo(NullaryMethodType(bundleTpe))
+
+        val cloneTypeImpl = localTyper.typed(DefDef(cloneTypeSym, neww))
+
+        // ==================== Generate _usingPlugin ====================
+        // Unclear why quasiquotes work here but didn't for cloneTypeSym, maybe they could.
+        val usingPlugin = localTyper.typed(q"override protected def _usingPlugin: Boolean = true")
+
+        val withMethods = deriveClassDef(bundle) { t =>
+          deriveTemplate(t)(_ :+ cloneTypeImpl :+ usingPlugin)
+        }
+
+        super.transform(localTyper.typed(withMethods))
+
+      case _ => super.transform(tree)
+    }
+  }
+}
diff --git a/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala b/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala
new file mode 100644
index 00000000..b1302ba3
--- /dev/null
+++ b/plugin/src/main/scala/chisel3/internal/plugin/ChiselComponent.scala
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package chisel3.internal.plugin
+
+import scala.collection.mutable
+import scala.reflect.internal.Flags
+import scala.tools.nsc
+import scala.tools.nsc.{Global, Phase}
+import scala.tools.nsc.plugins.PluginComponent
+import scala.tools.nsc.transform.TypingTransformers
+
+// The component of the chisel plugin. Not sure exactly what the difference is between
+//   a Plugin and a PluginComponent.
+class ChiselComponent(val global: Global) extends PluginComponent with TypingTransformers {
+  import global._
+  val runsAfter: List[String] = List[String]("typer")
+  val phaseName: String = "chiselcomponent"
+  def newPhase(_prev: Phase): ChiselComponentPhase = new ChiselComponentPhase(_prev)
+  class ChiselComponentPhase(prev: Phase) extends StdPhase(prev) {
+    override def name: String = phaseName
+    def apply(unit: CompilationUnit): Unit = {
+      // 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) {
+        unit.body = new MyTypingTransformer(unit).transform(unit.body)
+      }
+    }
+  }
+
+  class MyTypingTransformer(unit: CompilationUnit)
+    extends TypingTransformer(unit) {
+
+    private def shouldMatchGen(bases: Tree*): Type => Boolean = {
+      val cache = mutable.HashMap.empty[Type, Boolean]
+      val baseTypes = bases.map(inferType)
+
+      // If subtype of one of the base types, it's a match!
+      def terminate(t: Type): Boolean = baseTypes.exists(t <:< _)
+
+      // Recurse through subtype hierarchy finding containers
+      // Seen is only updated when we recurse into type parameters, thus it is typically small
+      def recShouldMatch(s: Type, seen: Set[Type]): Boolean = {
+        def outerMatches(t: Type): Boolean = {
+          val str = t.toString
+          str.startsWith("Option[") || str.startsWith("Iterable[")
+        }
+        if (terminate(s)) {
+          true
+        } else if (seen.contains(s)) {
+          false
+        } else if (outerMatches(s)) {
+          // These are type parameters, loops *are* possible here
+          recShouldMatch(s.typeArgs.head, seen + s)
+        } else {
+          // This is the standard inheritance hierarchy, Scalac catches loops here
+          s.parents.exists( p => recShouldMatch(p, seen) )
+        }
+      }
+
+      // If doesn't match container pattern, exit early
+      def earlyExit(t: Type): Boolean = {
+        !(t.matchesPattern(inferType(tq"Iterable[_]")) || t.matchesPattern(inferType(tq"Option[_]")))
+      }
+
+      // Return function so that it captures the cache
+      { q: Type =>
+        cache.getOrElseUpdate(q, {
+          // First check if a match, then check early exit, then recurse
+          if(terminate(q)){
+            true
+          } else if(earlyExit(q)) {
+            false
+          } else {
+            recShouldMatch(q, Set.empty)
+          }
+        })
+      }
+    }
+
+
+    private val shouldMatchData      : Type => Boolean = shouldMatchGen(tq"chisel3.Data")
+    private val shouldMatchDataOrMem : Type => Boolean = shouldMatchGen(tq"chisel3.Data", tq"chisel3.MemBase[_]")
+    private val shouldMatchModule    : Type => Boolean = shouldMatchGen(tq"chisel3.experimental.BaseModule")
+
+    // Given a type tree, infer the type and return it
+    private def inferType(t: Tree): Type = localTyper.typed(t, nsc.Mode.TYPEmode).tpe
+
+    // Indicates whether a ValDef is properly formed to get name
+    private def okVal(dd: ValDef): Boolean = {
+
+      // These were found through trial and error
+      def okFlags(mods: Modifiers): Boolean = {
+        val badFlags = Set(
+          Flag.PARAM,
+          Flag.SYNTHETIC,
+          Flag.DEFERRED,
+          Flags.TRIEDCOOKING,
+          Flags.CASEACCESSOR,
+          Flags.PARAMACCESSOR
+        )
+        badFlags.forall{ x => !mods.hasFlag(x)}
+      }
+
+      // Ensure expression isn't null, as you can't call `null.autoName("myname")`
+      val isNull = dd.rhs match {
+        case Literal(Constant(null)) => true
+        case _ => false
+      }
+
+      okFlags(dd.mods) && !isNull && dd.rhs != EmptyTree
+    }
+    // TODO Unify with okVal
+    private def okUnapply(dd: ValDef): Boolean = {
+
+      // These were found through trial and error
+      def okFlags(mods: Modifiers): Boolean = {
+        val badFlags = Set(
+          Flag.PARAM,
+          Flag.DEFERRED,
+          Flags.TRIEDCOOKING,
+          Flags.CASEACCESSOR,
+          Flags.PARAMACCESSOR
+        )
+        val goodFlags = Set(
+          Flag.SYNTHETIC,
+          Flag.ARTIFACT
+        )
+        goodFlags.forall(f => mods.hasFlag(f)) && badFlags.forall(f => !mods.hasFlag(f))
+      }
+
+      // Ensure expression isn't null, as you can't call `null.autoName("myname")`
+      val isNull = dd.rhs match {
+        case Literal(Constant(null)) => true
+        case _ => false
+      }
+      val tpe = inferType(dd.tpt)
+      definitions.isTupleType(tpe) && okFlags(dd.mods) && !isNull && dd.rhs != EmptyTree
+    }
+
+    private def findUnapplyNames(tree: Tree): Option[List[String]] = {
+      val applyArgs: Option[List[Tree]] = tree match {
+        case Match(_, List(CaseDef(_, _, Apply(_, args)))) => Some(args)
+        case _ => None
+      }
+      applyArgs.flatMap { args =>
+        var ok = true
+        val result = mutable.ListBuffer[String]()
+        args.foreach {
+          case Ident(TermName(name)) => result += name
+          // Anything unexpected and we abort
+          case _                     => ok = false
+        }
+        if (ok) Some(result.toList) else None
+      }
+    }
+
+    // Whether this val is directly enclosed by a Bundle type
+    private def inBundle(dd: ValDef): Boolean = {
+      dd.symbol.logicallyEnclosingMember.thisType <:< inferType(tq"chisel3.Bundle")
+    }
+
+    private def stringFromTermName(name: TermName): String =
+      name.toString.trim() // Remove trailing space (Scalac implementation detail)
+
+    // Method called by the compiler to modify source tree
+    override def transform(tree: Tree): Tree = tree match {
+      // Check if a subtree is a candidate
+      case dd @ ValDef(mods, name, tpt, rhs) if okVal(dd) =>
+        val tpe = inferType(tpt)
+        // If a Data and in a Bundle, just get the name but not a prefix
+        if (shouldMatchData(tpe) && inBundle(dd)) {
+          val str = stringFromTermName(name)
+          val newRHS = transform(rhs)  // chisel3.internal.plugin.autoNameRecursively
+          val named = q"chisel3.internal.plugin.autoNameRecursively($str)($newRHS)"
+          treeCopy.ValDef(dd, mods, name, tpt, localTyper typed named)
+        }
+        // If a Data or a Memory, get the name and a prefix
+        else if (shouldMatchDataOrMem(tpe)) {
+          val str = stringFromTermName(name)
+          val newRHS = transform(rhs)
+          val prefixed = q"chisel3.experimental.prefix.apply[$tpt](name=$str)(f=$newRHS)"
+          val named = q"chisel3.internal.plugin.autoNameRecursively($str)($prefixed)"
+          treeCopy.ValDef(dd, mods, name, tpt, localTyper typed named)
+          // If an instance, just get a name but no prefix
+        } else if (shouldMatchModule(tpe)) {
+          val str = stringFromTermName(name)
+          val newRHS = transform(rhs)
+          val named = q"chisel3.internal.plugin.autoNameRecursively($str)($newRHS)"
+          treeCopy.ValDef(dd, mods, name, tpt, localTyper typed named)
+        } else {
+          // Otherwise, continue
+          super.transform(tree)
+        }
+      case dd @ ValDef(mods, name, tpt, rhs @ Match(_, _)) if okUnapply(dd) =>
+        val tpe = inferType(tpt)
+        val fieldsOfInterest: List[Boolean] = tpe.typeArgs.map(shouldMatchData)
+        // Only transform if at least one field is of interest
+        if (fieldsOfInterest.reduce(_ || _)) {
+          findUnapplyNames(rhs) match {
+            case Some(names) =>
+              val onames: List[Option[String]] = fieldsOfInterest.zip(names).map { case (ok, name) => if (ok) Some(name) else None }
+              val named = q"chisel3.internal.plugin.autoNameRecursivelyProduct($onames)($rhs)"
+              treeCopy.ValDef(dd, mods, name, tpt, localTyper typed named)
+            case None => // It's not clear how this could happen but we don't want to crash
+              super.transform(tree)
+          }
+        } else {
+          super.transform(tree)
+        }
+      // Otherwise, continue
+      case _ => super.transform(tree)
+    }
+  }
+}
diff --git a/plugin/src/main/scala/chisel3/internal/plugin/ChiselPlugin.scala b/plugin/src/main/scala/chisel3/internal/plugin/ChiselPlugin.scala
new file mode 100644
index 00000000..23082329
--- /dev/null
+++ b/plugin/src/main/scala/chisel3/internal/plugin/ChiselPlugin.scala
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package chisel3.internal.plugin
+
+import scala.tools.nsc
+import nsc.Global
+import nsc.plugins.{Plugin, PluginComponent}
+import scala.reflect.internal.util.NoPosition
+
+private[plugin] case class ChiselPluginArguments(var useBundlePlugin: Boolean = true) {
+  def useBundlePluginOpt = "useBundlePlugin"
+  def useBundlePluginFullOpt = s"-P:chiselplugin:$useBundlePluginOpt"
+}
+
+// The plugin to be run by the Scala compiler during compilation of Chisel code
+class ChiselPlugin(val global: Global) extends Plugin {
+  val name = "chiselplugin"
+  val description = "Plugin for Chisel 3 Hardware Description Language"
+  private val arguments = ChiselPluginArguments()
+  val components: List[PluginComponent] = List[PluginComponent](
+    new ChiselComponent(global),
+    new BundleComponent(global, arguments)
+  )
+
+  override def init(options: List[String], error: String => Unit): Boolean = {
+    for (option <- options) {
+      if (option == arguments.useBundlePluginOpt) {
+        val msg = s"'${arguments.useBundlePluginFullOpt}' is now default behavior, you can stop using the scalacOption."
+        global.reporter.warning(NoPosition, msg)
+      } else {
+        error(s"Option not understood: '$option'")
+      }
+    }
+    true
+  }
+
+
+}
+