Run computeMaxLocalsMaxStack less often

Introduce a cache to remember which methods have maxLocals and
maxStack already computed. Before we were computing these values
on every run of eliminateUnreachableCode.

Also update the implementation of eliminateUnreachableCode to keep
correct max values.

1 files changed, 6 insertions, 9 deletions

diff --git a/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala
index 9cf6e366d2..f78d450db1 100644
--- a/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala
+++ b/test/junit/scala/tools/nsc/backend/jvm/analysis/NullnessAnalyzerTest.scala
@@ -31,25 +31,22 @@ object NullnessAnalyzerTest extends ClearAfterClass.Clearable {
 class NullnessAnalyzerTest extends ClearAfterClass {
   ClearAfterClass.stateToClear = NullnessAnalyzerTest
   val noOptCompiler = NullnessAnalyzerTest.noOptCompiler
+  import noOptCompiler.genBCode.bTypes.analyzers._
 
-  def newNullnessAnalyzer(methodNode: MethodNode, classInternalName: InternalName = "C"): NullnessAnalyzer = {
-    val nullnessAnalyzer = new NullnessAnalyzer
-    nullnessAnalyzer.analyze(classInternalName, methodNode)
-    nullnessAnalyzer
-  }
+  def newNullnessAnalyzer(methodNode: MethodNode, classInternalName: InternalName = "C") = new AsmAnalyzer(methodNode, classInternalName, new NullnessAnalyzer)
 
-  def testNullness(analyzer: NullnessAnalyzer, method: MethodNode, query: String, index: Int, nullness: NullnessValue): Unit = {
+  def testNullness(analyzer: AsmAnalyzer[NullnessValue], method: MethodNode, query: String, index: Int, nullness: NullnessValue): Unit = {
     for (i <- findInstr(method, query)) {
-      val r = analyzer.frameAt(i, method).getValue(index)
+      val r = analyzer.frameAt(i).getValue(index)
       assertTrue(s"Expected: $nullness, found: $r. At instr ${textify(i)}", nullness == r)
     }
   }
 
   // debug / helper for writing tests
-  def showAllNullnessFrames(analyzer: NullnessAnalyzer, method: MethodNode): String = {
+  def showAllNullnessFrames(analyzer: AsmAnalyzer[NullnessValue], method: MethodNode): String = {
     val instrLength = method.instructions.iterator.asScala.map(textify(_).length).max
     val lines = for (i <- method.instructions.iterator.asScala) yield {
-      val f = analyzer.frameAt(i, method)
+      val f = analyzer.frameAt(i)
       val frameString = {
         if (f == null) "null"
         else (0 until (f.getLocals + f.getStackSize)).iterator