From 11614455e71530292c1ed98dc4fbda5efee0b84d Mon Sep 17 00:00:00 2001
From: Lukas Rytz <lukas.rytz@gmail.com>
Date: Mon, 23 Nov 2015 15:26:45 +0100
Subject: Fix in "consumersOfOutputsFrom" query in prod-cons analysis

Fix the "consumersOfOutputsFrom" in the prod-cons analysis to support
dummy instructions:

  - UninitializedLocalProducer
  - ParameterProducer
  - ExceptionProducer
---
 .../jvm/analysis/ProdConsAnalyzerImpl.scala        | 31 +++++++++++++++-------
 1 file changed, 21 insertions(+), 10 deletions(-)

(limited to 'src/compiler')

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerImpl.scala b/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerImpl.scala
index f7ec55f305..894799bf36 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerImpl.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/analysis/ProdConsAnalyzerImpl.scala
@@ -94,8 +94,13 @@ trait ProdConsAnalyzerImpl {
     inputValues(insn).iterator.flatMap(v => v.insns.asScala).toSet
   }
 
-  def consumersOfOutputsFrom(insn: AbstractInsnNode): Set[AbstractInsnNode] =
-    _consumersOfOutputsFrom.get(insn).map(v => v.indices.flatMap(v.apply)(collection.breakOut): Set[AbstractInsnNode]).getOrElse(Set.empty)
+  def consumersOfOutputsFrom(insn: AbstractInsnNode): Set[AbstractInsnNode] = insn match {
+    case _: UninitializedLocalProducer                 => Set.empty
+    case ParameterProducer(local)                      => consumersOfValueAt(methodNode.instructions.getFirst, local)
+    case ExceptionProducer(handlerLabel, handlerFrame) => consumersOfValueAt(handlerLabel, handlerFrame.stackTop)
+    case _ =>
+      _consumersOfOutputsFrom.get(insn).map(v => v.indices.flatMap(v.apply)(collection.breakOut): Set[AbstractInsnNode]).getOrElse(Set.empty)
+  }
 
   /**
    * Returns the potential initial producer instructions of a value in the frame of `insn`.
@@ -151,9 +156,15 @@ trait ProdConsAnalyzerImpl {
     inputValueSlots(insn).flatMap(slot => initialProducersForValueAt(insn, slot)).toSet
   }
 
-  def ultimateConsumersOfOutputsFrom(insn: AbstractInsnNode): Set[AbstractInsnNode] = {
-    lazy val next = insn.getNext
-    outputValueSlots(insn).flatMap(slot => ultimateConsumersOfValueAt(next, slot)).toSet
+  def ultimateConsumersOfOutputsFrom(insn: AbstractInsnNode): Set[AbstractInsnNode] = insn match {
+    case _: UninitializedLocalProducer => Set.empty
+    case _ =>
+      lazy val next = insn match {
+        case _: ParameterProducer               => methodNode.instructions.getFirst
+        case ExceptionProducer(handlerLabel, _) => handlerLabel
+        case _                                  => insn.getNext
+      }
+      outputValueSlots(insn).flatMap(slot => ultimateConsumersOfValueAt(next, slot)).toSet
   }
 
   private def isCopyOperation(insn: AbstractInsnNode): Boolean = {
@@ -378,7 +389,7 @@ trait ProdConsAnalyzerImpl {
   private def outputValueSlots(insn: AbstractInsnNode): Seq[Int] = insn match {
     case ParameterProducer(local)          => Seq(local)
     case UninitializedLocalProducer(local) => Seq(local)
-    case ExceptionProducer(frame)          => Seq(frame.stackTop)
+    case ExceptionProducer(_, frame)       => Seq(frame.stackTop)
     case _ =>
       if (insn.getOpcode == -1) return Seq.empty
       if (isStore(insn)) {
@@ -443,9 +454,9 @@ abstract class InitialProducer extends AbstractInsnNode(-1) {
   override def accept(cv: MethodVisitor): Unit = throw new UnsupportedOperationException
 }
 
-case class ParameterProducer(local: Int)                         extends InitialProducer
-case class UninitializedLocalProducer(local: Int)                extends InitialProducer
-case class ExceptionProducer[V <: Value](handlerFrame: Frame[V]) extends InitialProducer
+case class ParameterProducer(local: Int)                                                  extends InitialProducer
+case class UninitializedLocalProducer(local: Int)                                         extends InitialProducer
+case class ExceptionProducer[V <: Value](handlerLabel: LabelNode, handlerFrame: Frame[V]) extends InitialProducer
 
 class InitialProducerSourceInterpreter extends SourceInterpreter {
   override def newParameterValue(isInstanceMethod: Boolean, local: Int, tp: Type): SourceValue = {
@@ -457,6 +468,6 @@ class InitialProducerSourceInterpreter extends SourceInterpreter {
   }
 
   override def newExceptionValue(tryCatchBlockNode: TryCatchBlockNode, handlerFrame: Frame[_ <: Value], exceptionType: Type): SourceValue = {
-    new SourceValue(1, ExceptionProducer(handlerFrame))
+    new SourceValue(1, ExceptionProducer(tryCatchBlockNode.handler, handlerFrame))
   }
 }
-- 
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