1 files changed, 31 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala b/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala
index 40f91cbed4..594fd8923c 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzer.scala
@@ -57,8 +57,20 @@ import scala.collection.convert.decorateAsScala._
  * copying operations.
  */
 class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName) {
+
+  /* Timers for benchmarking ProdCons
+  import scala.reflect.internal.util.Statistics._
+  import ProdConsAnalyzer._
+  val analyzerTimer = newSubTimer(classInternalName + "#" + methodNode.name + " - analysis", prodConsAnalyzerTimer)
+  val consumersTimer = newSubTimer(classInternalName + "#" + methodNode.name + " - consumers", prodConsAnalyzerTimer)
+  */
+
   val analyzer = new Analyzer(new InitialProducerSourceInterpreter)
+
+//  val start = analyzerTimer.start()
   analyzer.analyze(classInternalName, methodNode)
+//  analyzerTimer.stop(start)
+//  println(analyzerTimer.line)
 
   def frameAt(insn: AbstractInsnNode) = analyzer.frameAt(insn, methodNode)
 
@@ -103,7 +115,11 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName)
   def initialProducersForValueAt(insn: AbstractInsnNode, slot: Int): Set[AbstractInsnNode] = {
     def initialProducers(insn: AbstractInsnNode, producedSlot: Int): Set[AbstractInsnNode] = {
       if (isCopyOperation(insn)) {
-        _initialProducersCache.getOrElseUpdate((insn, producedSlot), {
+        val key = (insn, producedSlot)
+        _initialProducersCache.getOrElseUpdate(key, {
+          // prevent infinite recursion if an instruction is its own producer or consumer
+          // see cyclicProdCons in ProdConsAnalyzerTest
+          _initialProducersCache(key) = Set.empty
           val (sourceValue, sourceValueSlot) = copyOperationSourceValue(insn, producedSlot)
           sourceValue.insns.iterator.asScala.flatMap(initialProducers(_, sourceValueSlot)).toSet
         })
@@ -121,7 +137,11 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName)
   def ultimateConsumersOfValueAt(insn: AbstractInsnNode, slot: Int): Set[AbstractInsnNode] = {
     def ultimateConsumers(insn: AbstractInsnNode, consumedSlot: Int): Set[AbstractInsnNode] = {
       if (isCopyOperation(insn)) {
-        _ultimateConsumersCache.getOrElseUpdate((insn, consumedSlot), {
+        val key = (insn, consumedSlot)
+        _ultimateConsumersCache.getOrElseUpdate(key, {
+          // prevent infinite recursion if an instruction is its own producer or consumer
+          // see cyclicProdCons in ProdConsAnalyzerTest
+          _ultimateConsumersCache(key) = Set.empty
           for {
             producedSlot     <- copyOperationProducedValueSlots(insn, consumedSlot)
             consumer         <- consumersOfValueAt(insn.getNext, producedSlot)
@@ -384,6 +404,7 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName)
 
   /** For each instruction, a set of potential consumers of the produced values. */
   private lazy val _consumersOfOutputsFrom: Map[AbstractInsnNode, Vector[Set[AbstractInsnNode]]] = {
+//    val start = consumersTimer.start()
     var res = Map.empty[AbstractInsnNode, Vector[Set[AbstractInsnNode]]]
     for {
       insn <- methodNode.instructions.iterator.asScala
@@ -396,6 +417,8 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName)
       val outputIndex = producedSlots.indexOf(i)
       res = res.updated(producer, currentConsumers.updated(outputIndex, currentConsumers(outputIndex) + insn))
     }
+//    consumersTimer.stop(start)
+//    println(consumersTimer.line)
     res
   }
 
@@ -403,6 +426,11 @@ class ProdConsAnalyzer(methodNode: MethodNode, classInternalName: InternalName)
   private val _ultimateConsumersCache: mutable.AnyRefMap[(AbstractInsnNode, Int), Set[AbstractInsnNode]] = mutable.AnyRefMap.empty
 }
 
+object ProdConsAnalyzer {
+  import scala.reflect.internal.util.Statistics._
+  val prodConsAnalyzerTimer = newTimer("Time in ProdConsAnalyzer", "jvm")
+}
+
 /**
  * A class for pseudo-instructions representing the initial producers of local values that have
  * no producer instruction in the method:
@@ -447,4 +475,4 @@ class InitialProducerSourceInterpreter extends SourceInterpreter {
   override def newExceptionValue(tryCatchBlockNode: TryCatchBlockNode, handlerFrame: Frame[_ <: Value], exceptionType: Type): SourceValue = {
     new SourceValue(1, ExceptionProducer(handlerFrame))
   }
-}
\ No newline at end of file
+}