Move compiler and compiler tests to compiler dir

1 files changed, 198 insertions, 0 deletions

diff --git a/compiler/src/dotty/tools/dotc/transform/SyntheticMethods.scala b/compiler/src/dotty/tools/dotc/transform/SyntheticMethods.scala
new file mode 100644
index 000000000..9dfd92fe9
--- /dev/null
+++ b/compiler/src/dotty/tools/dotc/transform/SyntheticMethods.scala
@@ -0,0 +1,198 @@
+package dotty.tools.dotc
+package transform
+
+import core._
+import Symbols._, Types._, Contexts._, Names._, StdNames._, Constants._, SymUtils._
+import scala.collection.{ mutable, immutable }
+import Flags._
+import TreeTransforms._
+import DenotTransformers._
+import ast.Trees._
+import ast.untpd
+import Decorators._
+import NameOps._
+import ValueClasses.isDerivedValueClass
+import scala.collection.mutable.ListBuffer
+import scala.language.postfixOps
+
+/** Synthetic method implementations for case classes, case objects,
+ *  and value classes.
+ *  Selectively added to case classes/objects, unless a non-default
+ *  implementation already exists:
+ *    def equals(other: Any): Boolean
+ *    def hashCode(): Int
+ *    def canEqual(other: Any): Boolean
+ *    def toString(): String
+ *    def productArity: Int
+ *    def productPrefix: String
+ *  Special handling:
+ *    protected def readResolve(): AnyRef
+ *
+ *  Selectively added to value classes, unless a non-default
+ *  implementation already exists:
+ *
+ *    def equals(other: Any): Boolean
+ *    def hashCode(): Int
+ */
+class SyntheticMethods(thisTransformer: DenotTransformer) {
+  import ast.tpd._
+
+  private var myValueSymbols: List[Symbol] = Nil
+  private var myCaseSymbols: List[Symbol] = Nil
+
+  private def initSymbols(implicit ctx: Context) =
+    if (myValueSymbols.isEmpty) {
+      myValueSymbols = List(defn.Any_hashCode, defn.Any_equals)
+      myCaseSymbols = myValueSymbols ++ List(defn.Any_toString, defn.Product_canEqual,
+        defn.Product_productArity, defn.Product_productPrefix)
+    }
+
+  def valueSymbols(implicit ctx: Context) = { initSymbols; myValueSymbols }
+  def caseSymbols(implicit ctx: Context) = { initSymbols; myCaseSymbols }
+
+  /** The synthetic methods of the case or value class `clazz`.
+   */
+  def syntheticMethods(clazz: ClassSymbol)(implicit ctx: Context): List[Tree] = {
+    val clazzType = clazz.typeRef
+    lazy val accessors =
+      if (isDerivedValueClass(clazz))
+        clazz.termParamAccessors
+      else
+        clazz.caseAccessors
+
+    val symbolsToSynthesize: List[Symbol] =
+      if (clazz.is(Case)) caseSymbols
+      else if (isDerivedValueClass(clazz)) valueSymbols
+      else Nil
+
+    def syntheticDefIfMissing(sym: Symbol): List[Tree] = {
+      val existing = sym.matchingMember(clazz.thisType)
+      if (existing == sym || existing.is(Deferred)) syntheticDef(sym) :: Nil
+      else Nil
+    }
+
+    def syntheticDef(sym: Symbol): Tree = {
+      val synthetic = sym.copy(
+        owner = clazz,
+        flags = sym.flags &~ Deferred | Synthetic | Override,
+        coord = clazz.coord).enteredAfter(thisTransformer).asTerm
+
+      def forwardToRuntime(vrefss: List[List[Tree]]): Tree =
+        ref(defn.runtimeMethodRef("_" + sym.name.toString)).appliedToArgs(This(clazz) :: vrefss.head)
+
+      def ownName(vrefss: List[List[Tree]]): Tree =
+        Literal(Constant(clazz.name.stripModuleClassSuffix.decode.toString))
+
+      def syntheticRHS(implicit ctx: Context): List[List[Tree]] => Tree = synthetic.name match {
+        case nme.hashCode_ if isDerivedValueClass(clazz) => vrefss => valueHashCodeBody
+        case nme.hashCode_ => vrefss => caseHashCodeBody
+        case nme.toString_ => if (clazz.is(ModuleClass)) ownName else forwardToRuntime
+        case nme.equals_ => vrefss => equalsBody(vrefss.head.head)
+        case nme.canEqual_ => vrefss => canEqualBody(vrefss.head.head)
+        case nme.productArity => vrefss => Literal(Constant(accessors.length))
+        case nme.productPrefix => ownName
+      }
+      ctx.log(s"adding $synthetic to $clazz at ${ctx.phase}")
+      DefDef(synthetic, syntheticRHS(ctx.withOwner(synthetic)))
+    }
+
+    /** The class
+     *
+     *      case class C(x: T, y: U)
+     *
+     *  gets the equals method:
+     *
+     *      def equals(that: Any): Boolean =
+     *        (this eq that) || {
+     *          that match {
+     *            case x$0 @ (_: C) => this.x == this$0.x && this.y == x$0.y
+     *            case _ => false
+     *         }
+     *
+     *  If C is a value class the initial `eq` test is omitted.
+     */
+    def equalsBody(that: Tree)(implicit ctx: Context): Tree = {
+      val thatAsClazz = ctx.newSymbol(ctx.owner, nme.x_0, Synthetic, clazzType, coord = ctx.owner.pos) // x$0
+      def wildcardAscription(tp: Type) = Typed(Underscore(tp), TypeTree(tp))
+      val pattern = Bind(thatAsClazz, wildcardAscription(clazzType)) // x$0 @ (_: C)
+      val comparisons = accessors map (accessor =>
+        This(clazz).select(accessor).select(defn.Any_==).appliedTo(ref(thatAsClazz).select(accessor)))
+      val rhs = // this.x == this$0.x && this.y == x$0.y
+        if (comparisons.isEmpty) Literal(Constant(true)) else comparisons.reduceLeft(_ and _)
+      val matchingCase = CaseDef(pattern, EmptyTree, rhs) // case x$0 @ (_: C) => this.x == this$0.x && this.y == x$0.y
+      val defaultCase = CaseDef(wildcardAscription(defn.AnyType), EmptyTree, Literal(Constant(false))) // case _ => false
+      val matchExpr = Match(that, List(matchingCase, defaultCase))
+      if (isDerivedValueClass(clazz)) matchExpr
+      else {
+        val eqCompare = This(clazz).select(defn.Object_eq).appliedTo(that.asInstance(defn.ObjectType))
+        eqCompare or matchExpr
+      }
+    }
+
+    /** The class
+     *
+     *  class C(x: T) extends AnyVal
+     *
+     *  gets the hashCode method:
+     *
+     *    def hashCode: Int = x.hashCode()
+     */
+    def valueHashCodeBody(implicit ctx: Context): Tree = {
+      assert(accessors.length == 1)
+      ref(accessors.head).select(nme.hashCode_).ensureApplied
+    }
+
+    /** The class
+     *
+     *    case class C(x: T, y: T)
+     *
+     *  gets the hashCode method:
+     *
+     *    def hashCode: Int = {
+     *      <synthetic> var acc: Int = 0xcafebabe;
+     *      acc = Statics.mix(acc, x);
+     *      acc = Statics.mix(acc, Statics.this.anyHash(y));
+     *      Statics.finalizeHash(acc, 2)
+     *    }
+     */
+    def caseHashCodeBody(implicit ctx: Context): Tree = {
+      val acc = ctx.newSymbol(ctx.owner, "acc".toTermName, Mutable | Synthetic, defn.IntType, coord = ctx.owner.pos)
+      val accDef = ValDef(acc, Literal(Constant(0xcafebabe)))
+      val mixes = for (accessor <- accessors.toList) yield
+        Assign(ref(acc), ref(defn.staticsMethod("mix")).appliedTo(ref(acc), hashImpl(accessor)))
+      val finish = ref(defn.staticsMethod("finalizeHash")).appliedTo(ref(acc), Literal(Constant(accessors.size)))
+      Block(accDef :: mixes, finish)
+    }
+
+    /** The hashCode implementation for given symbol `sym`. */
+    def hashImpl(sym: Symbol)(implicit ctx: Context): Tree =
+      defn.scalaClassName(sym.info.finalResultType) match {
+        case tpnme.Unit | tpnme.Null               => Literal(Constant(0))
+        case tpnme.Boolean                         => If(ref(sym), Literal(Constant(1231)), Literal(Constant(1237)))
+        case tpnme.Int                             => ref(sym)
+        case tpnme.Short | tpnme.Byte | tpnme.Char => ref(sym).select(nme.toInt)
+        case tpnme.Long                            => ref(defn.staticsMethod("longHash")).appliedTo(ref(sym))
+        case tpnme.Double                          => ref(defn.staticsMethod("doubleHash")).appliedTo(ref(sym))
+        case tpnme.Float                           => ref(defn.staticsMethod("floatHash")).appliedTo(ref(sym))
+        case _                                     => ref(defn.staticsMethod("anyHash")).appliedTo(ref(sym))
+      }
+
+    /** The class
+     *
+     *    case class C(...)
+     *
+     *  gets the canEqual method
+     *
+     *    def canEqual(that: Any) = that.isInstanceOf[C]
+     */
+    def canEqualBody(that: Tree): Tree = that.isInstance(clazzType)
+
+    symbolsToSynthesize flatMap syntheticDefIfMissing
+  }
+
+  def addSyntheticMethods(impl: Template)(implicit ctx: Context) =
+    if (ctx.owner.is(Case) || isDerivedValueClass(ctx.owner))
+      cpy.Template(impl)(body = impl.body ++ syntheticMethods(ctx.owner.asClass))
+    else
+      impl
+}