Remove GenASM, merge remaining common code snippets

With GenBCode being the default and only supported backend for Java 8,
we can get rid of GenASM.

This commit also fixes/migrates/moves to pending/deletes tests which
depended on GenASM before.

Author: soc

src/compiler/scala/tools/nsc/Global.scala

@@ -28,7 +28,6 @@ import transform._
 import backend.icode.{ ICodes, GenICode, ICodeCheckers }
 import backend.{ ScalaPrimitives, JavaPlatform }
 import backend.jvm.GenBCode
-import backend.jvm.GenASM
 import backend.opt.{ Inliners, InlineExceptionHandlers, ConstantOptimization, ClosureElimination, DeadCodeElimination }
 import backend.icode.analysis._
 import scala.language.postfixOps
@@ -633,13 +632,6 @@ class Global(var currentSettings: Settings, var reporter: Reporter)
     val runsRightAfter = None
   } with DeadCodeElimination
 
-  // phaseName = "jvm", ASM-based version
-  object genASM extends {
-    val global: Global.this.type = Global.this
-    val runsAfter = List("dce")
-    val runsRightAfter = None
-  } with GenASM
-
   // phaseName = "bcode"
   object genBCode extends {
     val global: Global.this.type = Global.this

src/compiler/scala/tools/nsc/backend/JavaPlatform.scala

@@ -40,13 +40,9 @@ trait JavaPlatform extends Platform {
   def updateClassPath(subst: Map[ClassPath[AbstractFile], ClassPath[AbstractFile]]) =
     currentClassPath = Some(new DeltaClassPath(currentClassPath.get, subst))
 
-  private def classEmitPhase =
-    if (settings.isBCodeActive) genBCode
-    else genASM
-
   def platformPhases = List(
-    flatten,        // get rid of inner classes
-    classEmitPhase  // generate .class files
+    flatten,  // get rid of inner classes
+    genBCode  // generate .class files
   )
 
   lazy val externalEquals          = getDecl(BoxesRunTimeClass, nme.equals_)

src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala

@@ -25,7 +25,6 @@ abstract class BCodeSkelBuilder extends BCodeHelpers {
   import global._
   import bTypes._
   import coreBTypes._
-  import bCodeAsmCommon._
 
   /*
    * There's a dedicated PlainClassBuilder for each CompilationUnit,

src/compiler/scala/tools/nsc/backend/jvm/BCodeHelpers.scala

@@ -126,7 +126,7 @@ abstract class BTypes {
   /**
    * Obtain the BType for a type descriptor or internal name. For class descriptors, the ClassBType
    * is constructed by parsing the corresponding classfile.
-   * 
+   *
    * Some JVM operations use either a full descriptor or only an internal name. Example:
    *   ANEWARRAY java/lang/String    // a new array of strings (internal name for the String class)
    *   ANEWARRAY [Ljava/lang/String; // a new array of array of string (full descriptor for the String class)
@@ -932,7 +932,7 @@ abstract class BTypes {
             // the static flag in the InnerClass table has a special meaning, see InnerClass comment
             i.flags & ~Opcodes.ACC_STATIC,
             if (isStaticNestedClass) Opcodes.ACC_STATIC else 0
-          ) & BCodeAsmCommon.INNER_CLASSES_FLAGS
+          ) & BCodeHelpers.INNER_CLASSES_FLAGS
         )
     })
 
@@ -1192,4 +1192,4 @@ object BTypes {
   // no static way (without symbol table instance) to get to nme.ScalaATTR / ScalaSignatureATTR
   val ScalaAttributeName    = "Scala"
   val ScalaSigAttributeName = "ScalaSig"
-}
+}

src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala

@@ -28,10 +28,9 @@ import scala.tools.nsc.settings.ScalaSettings
 class BTypesFromSymbols[G <: Global](val global: G) extends BTypes {
   import global._
   import definitions._
+  import genBCode._
 
   val bCodeICodeCommon: BCodeICodeCommon[global.type] = new BCodeICodeCommon(global)
-  val bCodeAsmCommon: BCodeAsmCommon[global.type] = new BCodeAsmCommon(global)
-  import bCodeAsmCommon._
 
   val backendUtils: BackendUtils[this.type] = new BackendUtils(this)
 
@@ -220,7 +219,101 @@ class BTypesFromSymbols[G <: Global](val global: G) extends BTypes {
     assert(!primitiveTypeMap.contains(sym) || isCompilingPrimitive, sym)
   }
 
+  def implementedInterfaces(classSym: Symbol): List[Symbol] = {
+    // Additional interface parents based on annotations and other cues
+    def newParentForAnnotation(ann: AnnotationInfo): Option[Type] = ann.symbol match {
+      case RemoteAttr => Some(RemoteInterfaceClass.tpe)
+      case _          => None
+    }
+
+    // SI-9393: java annotations are interfaces, but the classfile / java source parsers make them look like classes.
+    def isInterfaceOrTrait(sym: Symbol) = sym.isInterface || sym.isTrait || sym.hasJavaAnnotationFlag
+
+    val classParents = {
+      val parents = classSym.info.parents
+      // SI-9393: the classfile / java source parsers add Annotation and ClassfileAnnotation to the
+      // parents of a java annotations. undo this for the backend (where we need classfile-level information).
+      if (classSym.hasJavaAnnotationFlag) parents.filterNot(c => c.typeSymbol == ClassfileAnnotationClass || c.typeSymbol == AnnotationClass)
+      else parents
+    }
+
+    val allParents = classParents ++ classSym.annotations.flatMap(newParentForAnnotation)
+
+    // We keep the superClass when computing minimizeParents to eliminate more interfaces.
+    // Example: T can be eliminated from D
+    //   trait T
+    //   class C extends T
+    //   class D extends C with T
+    val interfaces = erasure.minimizeParents(allParents) match {
+      case superClass :: ifs if !isInterfaceOrTrait(superClass.typeSymbol) =>
+        ifs
+      case ifs =>
+        // minimizeParents removes the superclass if it's redundant, for example:
+        //  trait A
+        //  class C extends Object with A  // minimizeParents removes Object
+        ifs
+    }
+    interfaces.map(_.typeSymbol)
+  }
+
+  /**
+   * The member classes of a class symbol. Note that the result of this method depends on the
+   * current phase, for example, after lambdalift, all local classes become member of the enclosing
+   * class.
+   *
+   * Impl classes are always considered top-level, see comment in BTypes.
+   */
+  private def memberClassesForInnerClassTable(classSymbol: Symbol): List[Symbol] = classSymbol.info.decls.collect({
+    case sym if sym.isClass && !considerAsTopLevelImplementationArtifact(sym) =>
+      sym
+    case sym if sym.isModule && !considerAsTopLevelImplementationArtifact(sym) => // impl classes get the lateMODULE flag in mixin
+      val r = exitingPickler(sym.moduleClass)
+      assert(r != NoSymbol, sym.fullLocationString)
+      r
+  })(collection.breakOut)
+
   private def setClassInfo(classSym: Symbol, classBType: ClassBType): ClassBType = {
+    /**
+     * Reconstruct the classfile flags from a Java defined class symbol.
+     *
+     * The implementation of this method is slightly different from `javaFlags` in BTypesFromSymbols.
+     * The javaFlags method is primarily used to map Scala symbol flags to sensible classfile flags
+     * that are used in the generated classfiles. For example, all classes emitted by the Scala
+     * compiler have ACC_PUBLIC.
+     *
+     * When building a [[ClassBType]] from a Java class symbol, the flags in the type's `info` have
+     * to correspond exactly to the flags in the classfile. For example, if the class is package
+     * protected (i.e., it doesn't have the ACC_PUBLIC flag), this needs to be reflected in the
+     * ClassBType. For example, the inliner needs the correct flags for access checks.
+     *
+     * Class flags are listed here:
+     *   https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.1-200-E.1
+     */
+    def javaClassfileFlags(classSym: Symbol): Int = {
+      assert(classSym.isJava, s"Expected Java class symbol, got ${classSym.fullName}")
+      import asm.Opcodes._
+      def enumFlags = ACC_ENUM | {
+        // Java enums have the `ACC_ABSTRACT` flag if they have a deferred method.
+        // We cannot trust `hasAbstractFlag`: the ClassfileParser adds `ABSTRACT` and `SEALED` to all
+        // Java enums for exhaustiveness checking.
+        val hasAbstractMethod = classSym.info.decls.exists(s => s.isMethod && s.isDeferred)
+        if (hasAbstractMethod) ACC_ABSTRACT else 0
+      }
+      GenBCode.mkFlags(
+        // SI-9393: the classfile / java source parser make java annotation symbols look like classes.
+        // here we recover the actual classfile flags.
+        if (classSym.hasJavaAnnotationFlag)                        ACC_ANNOTATION | ACC_INTERFACE | ACC_ABSTRACT else 0,
+        if (classSym.isPublic)                                     ACC_PUBLIC    else 0,
+        if (classSym.isFinal)                                      ACC_FINAL     else 0,
+        // see the link above. javac does the same: ACC_SUPER for all classes, but not interfaces.
+        if (classSym.isInterface)                                  ACC_INTERFACE else ACC_SUPER,
+        // for Java enums, we cannot trust `hasAbstractFlag` (see comment in enumFlags)
+        if (!classSym.hasJavaEnumFlag && classSym.hasAbstractFlag) ACC_ABSTRACT  else 0,
+        if (classSym.isArtifact)                                   ACC_SYNTHETIC else 0,
+        if (classSym.hasJavaEnumFlag)                              enumFlags     else 0
+      )
+    }
+
     // Check for isImplClass: trait implementation classes have NoSymbol as superClass
     // Check for hasAnnotationFlag for SI-9393: the classfile / java source parsers add
     // scala.annotation.Annotation as superclass to java annotations. In reality, java