Store SAM information in ClassBTypes

If a class (trait) is a SAM type, store the name and descriptor of the
SAM in the ClassBType's InlineInfo.

8 files changed, 205 insertions, 19 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
index 93f5159f89..42738d3e1c 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
@@ -390,6 +390,17 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
 
     val isEffectivelyFinal = classSym.isEffectivelyFinal
 
+    val sam = {
+      if (classSym.isImplClass || classSym.isEffectivelyFinal) None
+      else {
+        // Phase travel necessary. For example, nullary methods (getter of an abstract val) get an
+        // empty parameter list in later phases and would therefore be picked as SAM.
+        val samSym = exitingPickler(definitions.findSam(classSym.tpe))
+        if (samSym == NoSymbol) None
+        else Some(samSym.javaSimpleName.toString + methodSymToDescriptor(samSym))
+      }
+    }
+
     var warning = Option.empty[ClassSymbolInfoFailureSI9111]
 
     // Primitive methods cannot be inlined, so there's no point in building a MethodInlineInfo. Also, some
@@ -447,7 +458,7 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
         }
     }).toMap
 
-    InlineInfo(traitSelfType, isEffectivelyFinal, methodInlineInfos, warning)
+    InlineInfo(traitSelfType, isEffectivelyFinal, sam, methodInlineInfos, warning)
   }
 }
 
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala b/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala
index 55d181823b..12cd9c7f5c 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BTypes.scala
@@ -234,6 +234,7 @@ abstract class BTypes {
       InlineInfo(
         traitImplClassSelfType = None,
         isEffectivelyFinal = BytecodeUtils.isFinalClass(classNode),
+        sam = inliner.heuristics.javaSam(classNode.name),
         methodInfos = methodInfos,
         warning)
     }
@@ -1106,6 +1107,8 @@ object BTypes {
    * Metadata about a ClassBType, used by the inliner.
    *
    * More information may be added in the future to enable more elaborate inlinine heuristics.
+   * Note that this class should contain information that can only be obtained from the ClassSymbol.
+   * Information that can be computed from the ClassNode should be added to the call graph instead.
    *
    * @param traitImplClassSelfType `Some(tp)` if this InlineInfo describes a trait, and the `self`
    *                               parameter type of the methods in the implementation class is not
@@ -1124,6 +1127,8 @@ object BTypes {
    * @param isEffectivelyFinal     True if the class cannot have subclasses: final classes, module
    *                               classes, trait impl classes.
    *
+   * @param sam                    If this class is a SAM type, the SAM's "$name$descriptor".
+   *
    * @param methodInfos            The [[MethodInlineInfo]]s for the methods declared in this class.
    *                               The map is indexed by the string s"$name$descriptor" (to
    *                               disambiguate overloads).
@@ -1134,10 +1139,11 @@ object BTypes {
    */
   final case class InlineInfo(traitImplClassSelfType: Option[InternalName],
                               isEffectivelyFinal: Boolean,
+                              sam: Option[String],
                               methodInfos: Map[String, MethodInlineInfo],
                               warning: Option[ClassInlineInfoWarning])
 
-  val EmptyInlineInfo = InlineInfo(None, false, Map.empty, None)
+  val EmptyInlineInfo = InlineInfo(None, false, None, Map.empty, None)
 
   /**
    * Metadata about a method, used by the inliner.
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala b/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala
index 218cf0a416..160c1283f1 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala
@@ -8,7 +8,7 @@ package backend.jvm
 
 import scala.tools.asm
 import scala.tools.nsc.backend.jvm.opt._
-import scala.tools.nsc.backend.jvm.BTypes.{InlineInfo, MethodInlineInfo, InternalName}
+import scala.tools.nsc.backend.jvm.BTypes._
 import BackendReporting._
 import scala.tools.nsc.settings.ScalaSettings
 
@@ -444,7 +444,7 @@ class BTypesFromSymbols[G <: Global](val global: G) extends BTypes {
         case Right(classNode) =>
           inlineInfoFromClassfile(classNode)
         case Left(missingClass) =>
-          InlineInfo(None, false, Map.empty, Some(ClassNotFoundWhenBuildingInlineInfoFromSymbol(missingClass)))
+          EmptyInlineInfo.copy(warning = Some(ClassNotFoundWhenBuildingInlineInfoFromSymbol(missingClass)))
       }
     }
   }
@@ -467,7 +467,7 @@ class BTypesFromSymbols[G <: Global](val global: G) extends BTypes {
         flags = asm.Opcodes.ACC_SUPER | asm.Opcodes.ACC_PUBLIC | asm.Opcodes.ACC_FINAL,
         nestedClasses = nested,
         nestedInfo = None,
-        InlineInfo(None, true, Map.empty, None))) // no InlineInfo needed, scala never invokes methods on the mirror class
+        inlineInfo = EmptyInlineInfo.copy(isEffectivelyFinal = true))) // no method inline infos needed, scala never invokes methods on the mirror class
       c
     })
   }
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala
index dd1d70c65f..4492d0baf5 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/ByteCodeRepository.scala
@@ -132,6 +132,11 @@ class ByteCodeRepository[BT <: BTypes](val classPath: ClassFileLookup[AbstractFi
    * The method node for a method matching `name` and `descriptor`, accessed in class `ownerInternalNameOrArrayDescriptor`.
    * The declaration of the method may be in one of the parents.
    *
+   * TODO: make sure we always return the right method, the one being invoked. write tests.
+   *   - if there's an abstract and a concrete one. could possibly somehow the abstract be returned?
+   *   - with traits and default methods, if there is more than one default method inherited and
+   *     no override: what should be returned? We should not just inline one of the two.
+   *
    * @return The [[MethodNode]] of the requested method and the [[InternalName]] of its declaring
    *         class, or an error message if the method could not be found.
    */
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala
index e7dd5abc57..c885a29e16 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/InlineInfoAttribute.scala
@@ -47,15 +47,22 @@ case class InlineInfoAttribute(inlineInfo: InlineInfo) extends Attribute(InlineI
 
     result.putByte(InlineInfoAttribute.VERSION)
 
-    var hasSelfIsFinal = 0
-    if (inlineInfo.isEffectivelyFinal)               hasSelfIsFinal |= 1
-    if (inlineInfo.traitImplClassSelfType.isDefined) hasSelfIsFinal |= 2
-    result.putByte(hasSelfIsFinal)
+    var finalSelfSam = 0
+    if (inlineInfo.isEffectivelyFinal)               finalSelfSam |= 1
+    if (inlineInfo.traitImplClassSelfType.isDefined) finalSelfSam |= 2
+    if (inlineInfo.sam.isDefined)                    finalSelfSam |= 4
+    result.putByte(finalSelfSam)
 
     for (selfInternalName <- inlineInfo.traitImplClassSelfType) {
       result.putShort(cw.newUTF8(selfInternalName))
     }
 
+    for (samNameDesc <- inlineInfo.sam) {
+      val (name, desc) = samNameDesc.span(_ != '(')
+      result.putShort(cw.newUTF8(name))
+      result.putShort(cw.newUTF8(desc))
+    }
+
     // The method count fits in a short (the methods_count in a classfile is also a short)
     result.putShort(inlineInfo.methodInfos.size)
 
@@ -94,15 +101,20 @@ case class InlineInfoAttribute(inlineInfo: InlineInfo) extends Attribute(InlineI
 
     val version = nextByte()
     if (version == 1) {
-      val hasSelfIsFinal = nextByte()
-      val isFinal = (hasSelfIsFinal & 1) != 0
-      val hasSelf = (hasSelfIsFinal & 2) != 0
+      val finalSelfSam = nextByte()
+      val isFinal = (finalSelfSam & 1) != 0
+      val hasSelf = (finalSelfSam & 2) != 0
+      val hasSam  = (finalSelfSam & 4) != 0
 
-      val self = if (hasSelf) {
+      val self = if (!hasSelf) None else {
         val selfName = nextUTF8()
         Some(selfName)
-      } else {
-        None
+      }
+
+      val sam = if (!hasSam) None else {
+        val name = nextUTF8()
+        val desc = nextUTF8()
+        Some(name + desc)
       }
 
       val numEntries = nextShort()
@@ -118,7 +130,7 @@ case class InlineInfoAttribute(inlineInfo: InlineInfo) extends Attribute(InlineI
         (name + desc, MethodInlineInfo(isFinal, traitMethodWithStaticImplementation, isInline, isNoInline))
       }).toMap
 
-      InlineInfoAttribute(InlineInfo(self, isFinal, infos, None))
+      InlineInfoAttribute(InlineInfo(self, isFinal, sam, infos, None))
     } else {
       val msg = UnknownScalaInlineInfoVersion(cr.getClassName, version)
       InlineInfoAttribute(BTypes.EmptyInlineInfo.copy(warning = Some(msg)))
@@ -129,8 +141,10 @@ case class InlineInfoAttribute(inlineInfo: InlineInfo) extends Attribute(InlineI
 object InlineInfoAttribute {
   /**
    * [u1]    version
-   * [u1]    isEffectivelyFinal (<< 0), hasTraitImplClassSelfType (<< 1)
+   * [u1]    isEffectivelyFinal (<< 0), hasTraitImplClassSelfType (<< 1), hasSam (<< 2)
    * [u2]?   traitImplClassSelfType (reference)
+   * [u2]?   samName (reference)
+   * [u2]?   samDescriptor (reference)
    * [u2]    numMethodEntries
    *   [u2]  name (reference)
    *   [u2]  descriptor (reference)
@@ -145,4 +159,4 @@ object InlineInfoAttribute {
  * In order to instruct the ASM framework to de-serialize the ScalaInlineInfo attribute, we need
  * to pass a prototype instance when running the class reader.
  */
-object InlineInfoAttributePrototype extends InlineInfoAttribute(InlineInfo(null, false, null, null))
+object InlineInfoAttributePrototype extends InlineInfoAttribute(InlineInfo(null, false, null, null, null))
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala
index c5d2d212f4..035be3acdd 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/Inliner.scala
@@ -25,6 +25,8 @@ class Inliner[BT <: BTypes](val btypes: BT) {
   import btypes._
   import callGraph._
 
+  val heuristics: InlinerHeuristics[btypes.type] = new InlinerHeuristics(btypes)
+
   def eliminateUnreachableCodeAndUpdateCallGraph(methodNode: MethodNode, definingClass: InternalName): Unit = {
     localOpt.minimalRemoveUnreachableCode(methodNode, definingClass) foreach {
       case invocation: MethodInsnNode  => callGraph.removeCallsite(invocation, methodNode)
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/opt/InlinerHeuristics.scala b/src/compiler/scala/tools/nsc/backend/jvm/opt/InlinerHeuristics.scala
new file mode 100644
index 0000000000..09bb59cd4d
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/backend/jvm/opt/InlinerHeuristics.scala
@@ -0,0 +1,146 @@
+/* NSC -- new Scala compiler
+ * Copyright 2005-2014 LAMP/EPFL
+ * @author  Martin Odersky
+ */
+
+package scala.tools.nsc
+package backend.jvm
+package opt
+
+import scala.tools.nsc.backend.jvm.BTypes.InternalName
+
+class InlinerHeuristics[BT <: BTypes](val bTypes: BT) {
+  import bTypes._
+
+  /*
+  // using http://lihaoyi.github.io/Ammonite/
+
+  load.ivy("com.google.guava" % "guava" % "18.0")
+  val javaUtilFunctionClasses = {
+    val rt = System.getProperty("sun.boot.class.path").split(":").find(_.endsWith("lib/rt.jar")).get
+    val u = new java.io.File(rt).toURL
+    val l = new java.net.URLClassLoader(Array(u))
+    val cp = com.google.common.reflect.ClassPath.from(l)
+    cp.getTopLevelClasses("java.util.function").toArray.map(_.toString).toList
+  }
+
+  // found using IntelliJ's "Find Usages" on the @FunctionalInterface annotation
+  val otherClasses = List(
+    "com.sun.javafx.css.parser.Recognizer",
+    "java.awt.KeyEventDispatcher",
+    "java.awt.KeyEventPostProcessor",
+    "java.io.FileFilter",
+    "java.io.FilenameFilter",
+    "java.lang.Runnable",
+    "java.lang.Thread$UncaughtExceptionHandler",
+    "java.nio.file.DirectoryStream$Filter",
+    "java.nio.file.PathMatcher",
+    "java.time.temporal.TemporalAdjuster",
+    "java.time.temporal.TemporalQuery",
+    "java.util.Comparator",
+    "java.util.concurrent.Callable",
+    "java.util.logging.Filter",
+    "java.util.prefs.PreferenceChangeListener",
+    "javafx.animation.Interpolatable",
+    "javafx.beans.InvalidationListener",
+    "javafx.beans.value.ChangeListener",
+    "javafx.collections.ListChangeListener",
+    "javafx.collections.MapChangeListener",
+    "javafx.collections.SetChangeListener",
+    "javafx.event.EventHandler",
+    "javafx.util.Builder",
+    "javafx.util.BuilderFactory",
+    "javafx.util.Callback"
+  )
+
+  val allClasses = javaUtilFunctionClasses ::: otherClasses
+
+  load.ivy("org.ow2.asm" % "asm" % "5.0.4")
+  val classesAndSamNameDesc = allClasses.map(c => {
+    val cls = Class.forName(c)
+    val internalName = org.objectweb.asm.Type.getDescriptor(cls).drop(1).dropRight(1) // drop L and ;
+    val sams = cls.getMethods.filter(m => {
+      (m.getModifiers & java.lang.reflect.Modifier.ABSTRACT) != 0 &&
+      m.getName != "equals" // Comparator has an abstract override of "equals" for adding Javadoc
+    })
+    assert(sams.size == 1, internalName + sams.map(_.getName))
+    val sam = sams.head
+    val samDesc = org.objectweb.asm.Type.getMethodDescriptor(sam)
+    (internalName, sam.getName, samDesc)
+  })
+  println(classesAndSamNameDesc map {
+    case (cls, nme, desc) => s"""("$cls", "$nme$desc")"""
+  } mkString ("", ",\n", "\n"))
+  */
+  private val javaSams: Map[String, String] = Map(
+    ("java/util/function/BiConsumer", "accept(Ljava/lang/Object;Ljava/lang/Object;)V"),
+    ("java/util/function/BiFunction", "apply(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"),
+    ("java/util/function/BiPredicate", "test(Ljava/lang/Object;Ljava/lang/Object;)Z"),
+    ("java/util/function/BinaryOperator", "apply(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"),
+    ("java/util/function/BooleanSupplier", "getAsBoolean()Z"),
+    ("java/util/function/Consumer", "accept(Ljava/lang/Object;)V"),
+    ("java/util/function/DoubleBinaryOperator", "applyAsDouble(DD)D"),
+    ("java/util/function/DoubleConsumer", "accept(D)V"),
+    ("java/util/function/DoubleFunction", "apply(D)Ljava/lang/Object;"),
+    ("java/util/function/DoublePredicate", "test(D)Z"),
+    ("java/util/function/DoubleSupplier", "getAsDouble()D"),
+    ("java/util/function/DoubleToIntFunction", "applyAsInt(D)I"),
+    ("java/util/function/DoubleToLongFunction", "applyAsLong(D)J"),
+    ("java/util/function/DoubleUnaryOperator", "applyAsDouble(D)D"),
+    ("java/util/function/Function", "apply(Ljava/lang/Object;)Ljava/lang/Object;"),
+    ("java/util/function/IntBinaryOperator", "applyAsInt(II)I"),
+    ("java/util/function/IntConsumer", "accept(I)V"),
+    ("java/util/function/IntFunction", "apply(I)Ljava/lang/Object;"),
+    ("java/util/function/IntPredicate", "test(I)Z"),
+    ("java/util/function/IntSupplier", "getAsInt()I"),
+    ("java/util/function/IntToDoubleFunction", "applyAsDouble(I)D"),
+    ("java/util/function/IntToLongFunction", "applyAsLong(I)J"),
+    ("java/util/function/IntUnaryOperator", "applyAsInt(I)I"),
+    ("java/util/function/LongBinaryOperator", "applyAsLong(JJ)J"),
+    ("java/util/function/LongConsumer", "accept(J)V"),
+    ("java/util/function/LongFunction", "apply(J)Ljava/lang/Object;"),
+    ("java/util/function/LongPredicate", "test(J)Z"),
+    ("java/util/function/LongSupplier", "getAsLong()J"),
+    ("java/util/function/LongToDoubleFunction", "applyAsDouble(J)D"),
+    ("java/util/function/LongToIntFunction", "applyAsInt(J)I"),
+    ("java/util/function/LongUnaryOperator", "applyAsLong(J)J"),
+    ("java/util/function/ObjDoubleConsumer", "accept(Ljava/lang/Object;D)V"),
+    ("java/util/function/ObjIntConsumer", "accept(Ljava/lang/Object;I)V"),
+    ("java/util/function/ObjLongConsumer", "accept(Ljava/lang/Object;J)V"),
+    ("java/util/function/Predicate", "test(Ljava/lang/Object;)Z"),
+    ("java/util/function/Supplier", "get()Ljava/lang/Object;"),
+    ("java/util/function/ToDoubleBiFunction", "applyAsDouble(Ljava/lang/Object;Ljava/lang/Object;)D"),
+    ("java/util/function/ToDoubleFunction", "applyAsDouble(Ljava/lang/Object;)D"),
+    ("java/util/function/ToIntBiFunction", "applyAsInt(Ljava/lang/Object;Ljava/lang/Object;)I"),
+    ("java/util/function/ToIntFunction", "applyAsInt(Ljava/lang/Object;)I"),
+    ("java/util/function/ToLongBiFunction", "applyAsLong(Ljava/lang/Object;Ljava/lang/Object;)J"),
+    ("java/util/function/ToLongFunction", "applyAsLong(Ljava/lang/Object;)J"),
+    ("java/util/function/UnaryOperator", "apply(Ljava/lang/Object;)Ljava/lang/Object;"),
+    ("com/sun/javafx/css/parser/Recognizer", "recognize(I)Z"),
+    ("java/awt/KeyEventDispatcher", "dispatchKeyEvent(Ljava/awt/event/KeyEvent;)Z"),
+    ("java/awt/KeyEventPostProcessor", "postProcessKeyEvent(Ljava/awt/event/KeyEvent;)Z"),
+    ("java/io/FileFilter", "accept(Ljava/io/File;)Z"),
+    ("java/io/FilenameFilter", "accept(Ljava/io/File;Ljava/lang/String;)Z"),
+    ("java/lang/Runnable", "run()V"),
+    ("java/lang/Thread$UncaughtExceptionHandler", "uncaughtException(Ljava/lang/Thread;Ljava/lang/Throwable;)V"),
+    ("java/nio/file/DirectoryStream$Filter", "accept(Ljava/lang/Object;)Z"),
+    ("java/nio/file/PathMatcher", "matches(Ljava/nio/file/Path;)Z"),
+    ("java/time/temporal/TemporalAdjuster", "adjustInto(Ljava/time/temporal/Temporal;)Ljava/time/temporal/Temporal;"),
+    ("java/time/temporal/TemporalQuery", "queryFrom(Ljava/time/temporal/TemporalAccessor;)Ljava/lang/Object;"),
+    ("java/util/Comparator", "compare(Ljava/lang/Object;Ljava/lang/Object;)I"),
+    ("java/util/concurrent/Callable", "call()Ljava/lang/Object;"),
+    ("java/util/logging/Filter", "isLoggable(Ljava/util/logging/LogRecord;)Z"),
+    ("java/util/prefs/PreferenceChangeListener", "preferenceChange(Ljava/util/prefs/PreferenceChangeEvent;)V"),
+    ("javafx/animation/Interpolatable", "interpolate(Ljava/lang/Object;D)Ljava/lang/Object;"),
+    ("javafx/beans/InvalidationListener", "invalidated(Ljavafx/beans/Observable;)V"),
+    ("javafx/beans/value/ChangeListener", "changed(Ljavafx/beans/value/ObservableValue;Ljava/lang/Object;Ljava/lang/Object;)V"),
+    ("javafx/collections/ListChangeListener", "onChanged(Ljavafx/collections/ListChangeListener$Change;)V"),
+    ("javafx/collections/MapChangeListener", "onChanged(Ljavafx/collections/MapChangeListener$Change;)V"),
+    ("javafx/collections/SetChangeListener", "onChanged(Ljavafx/collections/SetChangeListener$Change;)V"),
+    ("javafx/event/EventHandler", "handle(Ljavafx/event/Event;)V"),
+    ("javafx/util/Builder", "build()Ljava/lang/Object;"),
+    ("javafx/util/BuilderFactory", "getBuilder(Ljava/lang/Class;)Ljavafx/util/Builder;"),
+    ("javafx/util/Callback", "call(Ljava/lang/Object;)Ljava/lang/Object;")
+  )
+  def javaSam(internalName: InternalName): Option[String] = javaSams.get(internalName)
+}
diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
index 02fa3c882b..14487a941b 100644
--- a/src/reflect/scala/reflect/internal/Definitions.scala
+++ b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -795,7 +795,9 @@ trait Definitions extends api.StandardDefinitions {
      * The class defining the method is a supertype of `tp` that
      * has a public no-arg primary constructor.
      */
-    def samOf(tp: Type): Symbol = if (!settings.Xexperimental) NoSymbol else {
+    def samOf(tp: Type): Symbol = if (!settings.Xexperimental) NoSymbol else findSam(tp)
+
+    def findSam(tp: Type): Symbol = {
       // if tp has a constructor, it must be public and must not take any arguments
       // (not even an implicit argument list -- to keep it simple for now)
       val tpSym  = tp.typeSymbol