Implement most of the Scala.js IR code generator.

src/dotty/tools/backend/sjs/JSDefinitions.scala

@@ -5,6 +5,7 @@ import dotty.tools.dotc.core._
 import Types._
 import Contexts._
 import Symbols._
+import Names._
 import StdNames._
 import Decorators._
 
@@ -172,4 +173,27 @@ final class JSDefinitions()(implicit ctx: Context) {
   lazy val BoxesRunTime_unboxToCharR = defn.BoxesRunTimeModule.requiredMethodRef("unboxToChar")
   def BoxesRunTime_unboxToChar(implicit ctx: Context): Symbol = BoxesRunTime_unboxToCharR.symbol
 
+  /** If `cls` is a class in the scala package, its name, otherwise EmptyTypeName */
+  private def scalajsClassName(cls: Symbol)(implicit ctx: Context): TypeName =
+    if (cls.isClass && cls.owner == ScalaJSJSPackageClass) cls.asClass.name
+    else EmptyTypeName
+
+  /** Is the given `cls` a class of the form `scala.scalajs.js.prefixN` where
+   *  `N` is a number.
+   *
+   *  This is similar to `isVarArityClass` in `Definitions.scala`.
+   */
+  private def isScalaJSVarArityClass(cls: Symbol, prefix: Name): Boolean = {
+    val name = scalajsClassName(cls)
+    name.startsWith(prefix) && name.drop(prefix.length).forall(_.isDigit)
+  }
+
+  def isJSFunctionClass(cls: Symbol): Boolean =
+    isScalaJSVarArityClass(cls, nme.Function)
+
+  private val ThisFunctionName = termName("ThisFunction")
+
+  def isJSThisFunctionClass(cls: Symbol): Boolean =
+    isScalaJSVarArityClass(cls, ThisFunctionName)
+
 }

src/dotty/tools/backend/sjs/JSEncoding.scala

@@ -19,6 +19,7 @@ import ir.{Trees => js, Types => jstpe}
 
 import ScopedVar.withScopedVars
 import JSDefinitions._
+import JSInterop._
 
 /** Encoding of symbol names for JavaScript
  *
@@ -139,17 +140,32 @@ object JSEncoding {
    *  java.lang.String, which is the `this` parameter.
    */
   def encodeRTStringMethodSym(sym: Symbol)(
-      implicit ctx: Context, pos: ir.Position): (Symbol, js.Ident) = {
-    require(sym.is(Flags.Method), "encodeMethodSym called with non-method symbol: " + sym)
+      implicit ctx: Context, pos: ir.Position): js.Ident = {
     require(sym.owner == defn.StringClass)
     require(!sym.isClassConstructor && !sym.is(Flags.Private))
 
     val (encodedName, paramsString) =
       encodeMethodNameInternal(sym, inRTClass = true)
-    val methodIdent = js.Ident(encodedName + paramsString,
+    js.Ident(encodedName + paramsString,
         Some(sym.unexpandedName.decoded + paramsString))
+  }
+
+  /** Encodes a constructor symbol of java.lang.String for use in RuntimeString.
+   *
+   *  - The name is rerouted to `newString`
+   *  - The result type is set to `java.lang.String`
+   */
+  def encodeRTStringCtorSym(sym: Symbol)(
+      implicit ctx: Context, pos: ir.Position): js.Ident = {
+    require(sym.owner == defn.StringClass)
+    require(sym.isClassConstructor && !sym.is(Flags.Private))
 
-    (jsdefn.RuntimeStringModuleClass, methodIdent)
+    val paramTypeNames = sym.info.firstParamTypes.map(internalName(_))
+    val paramAndResultTypeNames = paramTypeNames :+ ir.Definitions.StringClass
+    val paramsString = makeParamsString(paramAndResultTypeNames)
+
+    js.Ident("newString" + paramsString,
+        Some(sym.unexpandedName.decoded + paramsString))
   }
 
   private def encodeMethodNameInternal(sym: Symbol,
@@ -197,7 +213,7 @@ object JSEncoding {
 
   def encodeClassType(sym: Symbol)(implicit ctx: Context): jstpe.Type = {
     if (sym == defn.ObjectClass) jstpe.AnyType
-    else if (isRawJSType(sym)) jstpe.AnyType
+    else if (isJSType(sym)) jstpe.AnyType
     else {
       assert(sym != defn.ArrayClass,
           "encodeClassType() cannot be called with ArrayClass")
@@ -210,20 +226,17 @@ object JSEncoding {
     js.Ident(encodeClassFullName(sym), Some(sym.fullName.toString))
   }
 
-  def encodeClassFullName(sym: Symbol)(implicit ctx: Context): String =
-    ir.Definitions.encodeClassName(sym.fullName.toString)
+  def encodeClassFullName(sym: Symbol)(implicit ctx: Context): String = {
+    if (sym == defn.NothingClass) ir.Definitions.RuntimeNothingClass
+    else if (sym == defn.NullClass) ir.Definitions.RuntimeNullClass
+    else ir.Definitions.encodeClassName(sym.fullName.toString)
+  }
 
   private def encodeMemberNameInternal(sym: Symbol)(
       implicit ctx: Context): String = {
-    sym.name.toString.replace("_", "$und")
+    sym.name.toString.replace("_", "$und").replace("~", "$tilde")
   }
 
-  def isRawJSType(sym: Symbol)(implicit ctx: Context): Boolean =
-    sym.hasAnnotation(jsdefn.RawJSTypeAnnot)
-
-  def isScalaJSDefinedJSClass(sym: Symbol)(implicit ctx: Context): Boolean =
-    isRawJSType(sym) && !sym.hasAnnotation(jsdefn.JSNativeAnnot)
-
   def toIRType(tp: Type)(implicit ctx: Context): jstpe.Type = {
     val refType = toReferenceTypeInternal(tp)
     refType._1 match {
@@ -243,7 +256,7 @@ object JSEncoding {
           else
             jstpe.IntType
         } else {
-          if (sym == defn.ObjectClass || isRawJSType(sym))
+          if (sym == defn.ObjectClass || isJSType(sym))
             jstpe.AnyType
           else if (sym == defn.NothingClass)
             jstpe.NothingType

src/dotty/tools/backend/sjs/JSInterop.scala

@@ -0,0 +1,110 @@
+package dotty.tools.backend.sjs
+
+import dotty.tools.dotc.core._
+import Contexts._
+import Flags._
+import Symbols._
+import NameOps._
+import StdNames._
+
+import JSDefinitions._
+
+/** Management of the interoperability with JavaScript. */
+object JSInterop {
+
+  /** Is this symbol a JavaScript type? */
+  def isJSType(sym: Symbol)(implicit ctx: Context): Boolean = {
+    //sym.hasAnnotation(jsdefn.RawJSTypeAnnot)
+    ctx.atPhase(ctx.erasurePhase) { implicit ctx =>
+      sym.derivesFrom(jsdefn.JSAnyClass)
+    }
+  }
+
+  /** Is this symbol a Scala.js-defined JS class, i.e., a non-native JS class? */
+  def isScalaJSDefinedJSClass(sym: Symbol)(implicit ctx: Context): Boolean =
+    isJSType(sym) && !sym.hasAnnotation(jsdefn.JSNativeAnnot)
+
+  /** Should this symbol be translated into a JS getter?
+   *
+   *  This is true for any parameterless method, i.e., defined without `()`.
+   *  Unlike `SymDenotations.isGetter`, it applies to user-defined methods as
+   *  much as *accessor* methods created for `val`s and `var`s.
+   */
+  def isJSGetter(sym: Symbol)(implicit ctx: Context): Boolean = {
+    sym.info.firstParamTypes.isEmpty && ctx.atPhase(ctx.erasurePhase) { implicit ctx =>
+      sym.info.isParameterless
+    }
+  }
+
+  /** Should this symbol be translated into a JS setter?
+   *
+   *  This is true for any method whose name ends in `_=`.
+   *  Unlike `SymDenotations.isGetter`, it applies to user-defined methods as
+   *  much as *accessor* methods created for `var`s.
+   */
+  def isJSSetter(sym: Symbol)(implicit ctx: Context): Boolean =
+    sym.name.isSetterName && sym.is(Method)
+
+  /** Should this symbol be translated into a JS bracket access?
+   *
+   *  This is true for methods annotated with `@JSBracketAccess`.
+   */
+  def isJSBracketAccess(sym: Symbol)(implicit ctx: Context): Boolean =
+    sym.hasAnnotation(jsdefn.JSBracketAccessAnnot)
+
+  /** Should this symbol be translated into a JS bracket call?
+   *
+   *  This is true for methods annotated with `@JSBracketCall`.
+   */
+  def isJSBracketCall(sym: Symbol)(implicit ctx: Context): Boolean =
+    sym.hasAnnotation(jsdefn.JSBracketCallAnnot)
+
+  /** Is this symbol a default param accessor for a JS method?
+   *
+   *  For default param accessors of *constructors*, we need to test whether
+   *  the companion *class* of the owner is a JS type; not whether the owner
+   *  is a JS type.
+   */
+  def isJSDefaultParam(sym: Symbol)(implicit ctx: Context): Boolean = {
+    sym.name.isDefaultGetterName && {
+      val owner = sym.owner
+      if (owner.is(ModuleClass) &&
+          sym.name.asTermName.defaultGetterToMethod == nme.CONSTRUCTOR) {
+        isJSType(owner.linkedClass)
+      } else {
+        isJSType(owner)
+      }
+    }
+  }
+
+  /** Gets the unqualified JS name of a symbol.
+   *
+   *  If it is not explicitly specified with an `@JSName` annotation, the
+   *  JS name is inferred from the Scala name.
+   */
+  def jsNameOf(sym: Symbol)(implicit ctx: Context): String = {
+    sym.getAnnotation(jsdefn.JSNameAnnot).flatMap(_.argumentConstant(0)).fold {
+      val base = sym.name.unexpandedName.decode.toString.stripSuffix("_=")
+      if (sym.is(ModuleClass)) base.stripSuffix("$")
+      else if (!sym.is(Method)) base.stripSuffix(" ")
+      else base
+    } { constant =>
+      constant.stringValue
+    }
+  }
+
+  /** Gets the fully qualified JS name of a static class of module Symbol.
+   *
+   *  This is the JS name of the symbol qualified by the fully qualified JS
+   *  name of its original owner if the latter is a native JS object.
+   */
+  def fullJSNameOf(sym: Symbol)(implicit ctx: Context): String = {
+    assert(sym.isClass, s"fullJSNameOf called for non-class symbol $sym")
+    sym.getAnnotation(jsdefn.JSFullNameAnnot).flatMap(_.argumentConstant(0)).fold {
+      jsNameOf(sym)
+    } { constant =>
+      constant.stringValue
+    }
+  }
+
+}

src/dotty/tools/backend/sjs/JSPrimitives.scala

@@ -37,10 +37,13 @@ object JSPrimitives {
   final val ENV_INFO = 316      // runtime.environmentInfo
   final val LINKING_INFO = 317  // runtime.linkingInfo
 
+  final val THROW = 318 // <special-ops>.throw
+
 }
 
 class JSPrimitives(ctx: Context) extends DottyPrimitives(ctx) {
   import JSPrimitives._
+  import scala.tools.nsc.backend.ScalaPrimitives._
 
   private lazy val jsPrimitives: Map[Symbol, Int] = initJSPrimitives(ctx)
 
@@ -77,6 +80,18 @@ class JSPrimitives(ctx: Context) extends DottyPrimitives(ctx) {
 
     val jsdefn = JSDefinitions.jsdefn
 
+    // For some reason, the JVM primitive set does not register those
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newBooleanArray")), NEW_ZARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newByteArray")), NEW_BARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newShortArray")), NEW_SARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newCharArray")), NEW_CARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newIntArray")), NEW_IARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newLongArray")), NEW_LARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newFloatArray")), NEW_FARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newDoubleArray")), NEW_DARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newRefArray")), NEW_OARRAY)
+    addPrimitive(defn.DottyArraysModule.requiredMethod(Names.termName("newUnitArray")), NEW_OARRAY)
+
     addPrimitive(defn.Any_getClass, GETCLASS)
 
     for (i <- 0 to 22)
@@ -107,6 +122,8 @@ class JSPrimitives(ctx: Context) extends DottyPrimitives(ctx) {
     //addPrimitive(jsdefn.Runtime_environmentInfo, ENV_INFO)
     //addPrimitive(jsdefn.Runtime_linkingInfo, LINKING_INFO)
 
+    addPrimitive(defn.throwMethod, THROW)
+
     primitives.toMap
   }
 

src/dotty/tools/dotc/Compiler.scala

@@ -103,7 +103,11 @@ class Compiler {
   def rootContext(implicit ctx: Context): Context = {
     ctx.initialize()(ctx)
     val actualPhases = if (ctx.settings.scalajs.value) {
-      phases
+      // Remove phases that Scala.js does not want
+      phases.mapConserve(_.filter {
+        case _: FunctionalInterfaces => false
+        case _ => true
+      }).filter(_.nonEmpty)
     } else {
       // Remove Scala.js-related phases
       phases.mapConserve(_.filter {

src/dotty/tools/dotc/config/JavaPlatform.scala

@@ -7,6 +7,7 @@ import ClassPath.{ JavaContext, DefaultJavaContext }
 import core._
 import Symbols._, Types._, Contexts._, Denotations._, SymDenotations._, StdNames._, Names._
 import Flags._, Scopes._, Decorators._, NameOps._, util.Positions._
+import transform.ExplicitOuter, transform.SymUtils._
 
 class JavaPlatform extends Platform {
 
@@ -38,6 +39,14 @@ class JavaPlatform extends Platform {
 
   def rootLoader(root: TermSymbol)(implicit ctx: Context): SymbolLoader = new ctx.base.loaders.PackageLoader(root, classPath)
 
+  /** Is the SAMType `cls` also a SAM under the rules of the JVM? */
+  def isSam(cls: ClassSymbol)(implicit ctx: Context): Boolean =
+    cls.is(NoInitsTrait) &&
+    cls.superClass == defn.ObjectClass &&
+    cls.directlyInheritedTraits.forall(_.is(NoInits)) &&
+    !ExplicitOuter.needsOuterIfReferenced(cls) &&
+    cls.typeRef.fields.isEmpty // Superaccessors already show up as abstract methods here, so no test necessary
+
   /** We could get away with excluding BoxedBooleanClass for the
    *  purpose of equality testing since it need not compare equal
    *  to anything but other booleans, but it should be present in

src/dotty/tools/dotc/config/Platform.scala

@@ -27,6 +27,9 @@ abstract class Platform {
   /** Any platform-specific phases. */
   //def platformPhases: List[SubComponent]
 
+  /** Is the SAMType `cls` also a SAM under the rules of the platform? */
+  def isSam(cls: ClassSymbol)(implicit ctx: Context): Boolean
+
   /** The various ways a boxed primitive might materialize at runtime. */
   def isMaybeBoxed(sym: ClassSymbol)(implicit ctx: Context): Boolean
 

src/dotty/tools/dotc/config/SJSPlatform.scala

@@ -2,6 +2,7 @@ package dotty.tools.dotc.config
 
 import dotty.tools.dotc.core._
 import Contexts._
+import Symbols._
 
 import dotty.tools.backend.sjs.JSDefinitions
 
@@ -10,4 +11,8 @@ class SJSPlatform()(implicit ctx: Context) extends JavaPlatform {
   /** Scala.js-specific definitions. */
   val jsDefinitions: JSDefinitions = new JSDefinitions()
 
+  /** Is the SAMType `cls` also a SAM under the rules of the Scala.js back-end? */
+  override def isSam(cls: ClassSymbol)(implicit ctx: Context): Boolean =
+    defn.isFunctionClass(cls) || jsDefinitions.isJSFunctionClass(cls)
+
 }

src/dotty/tools/dotc/core/Phases.scala

@@ -233,8 +233,10 @@ object Phases {
     private val picklerCache = new PhaseCache(classOf[Pickler])
 
     private val refChecksCache = new PhaseCache(classOf[RefChecks])
+    private val elimRepeatedCache = new PhaseCache(classOf[ElimRepeated])
     private val extensionMethodsCache = new PhaseCache(classOf[ExtensionMethods])
     private val erasureCache = new PhaseCache(classOf[Erasure])
+    private val elimErasedValueTypeCache = new PhaseCache(classOf[ElimErasedValueType])
     private val patmatCache = new PhaseCache(classOf[PatternMatcher])
     private val lambdaLiftCache = new PhaseCache(classOf[LambdaLift])
     private val flattenCache = new PhaseCache(classOf[Flatten])
@@ -245,8 +247,10 @@ object Phases {
     def typerPhase = typerCache.phase
     def picklerPhase = picklerCache.phase
     def refchecksPhase = refChecksCache.phase
+    def elimRepeatedPhase = elimRepeatedCache.phase
     def extensionMethodsPhase = extensionMethodsCache.phase
     def erasurePhase = erasureCache.phase
+    def elimErasedValueTypePhase = elimErasedValueTypeCache.phase
     def patmatPhase = patmatCache.phase
     def lambdaLiftPhase = lambdaLiftCache.phase
     def flattenPhase = flattenCache.phase

src/dotty/tools/dotc/transform/ExpandSAMs.scala

@@ -25,21 +25,17 @@ class ExpandSAMs extends MiniPhaseTransform { thisTransformer =>
 
   import ast.tpd._
 
-  /** Is SAMType `cls` also a SAM under the rules of the JVM? */
-  def isJvmSam(cls: ClassSymbol)(implicit ctx: Context): Boolean =
-    cls.is(NoInitsTrait) &&
-    cls.superClass == defn.ObjectClass &&
-    cls.directlyInheritedTraits.forall(_.is(NoInits)) &&
-    !ExplicitOuter.needsOuterIfReferenced(cls) &&
-    cls.typeRef.fields.isEmpty // Superaccessors already show up as abstract methods here, so no test necessary
+  /** Is the SAMType `cls` also a SAM under the rules of the platform? */
+  def isPlatformSam(cls: ClassSymbol)(implicit ctx: Context): Boolean =
+    ctx.platform.isSam(cls)
 
   override def transformBlock(tree: Block)(implicit ctx: Context, info: TransformerInfo): Tree = tree match {
     case Block(stats @ (fn: DefDef) :: Nil, Closure(_, fnRef, tpt)) if fnRef.symbol == fn.symbol =>
       tpt.tpe match {
         case NoType => tree // it's a plain function
         case tpe @ SAMType(_) if tpe.isRef(defn.PartialFunctionClass) =>
           toPartialFunction(tree)
-        case tpe @ SAMType(_) if isJvmSam(tpe.classSymbol.asClass) =>
+        case tpe @ SAMType(_) if isPlatformSam(tpe.classSymbol.asClass) =>
           tree
         case tpe =>
           cpy.Block(tree)(stats,