Track aliases of primitive values in AliasingFrame

This allows using an AliasingAnalyzer for copy propagation
(subsequent commit).

2 files changed, 64 insertions, 1 deletions

diff --git a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala
index 1f2ec274d3..c071745788 100644
--- a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala
+++ b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala
@@ -179,7 +179,7 @@ object CodeGenTools {
   def findInstr(method: MethodNode, query: String): List[AbstractInsnNode] = {
     val useNext = query(0) == '+'
     val instrPart = if (useNext) query.drop(1) else query
-    val insns = method.instructions.iterator.asScala.find(i => textify(i) contains instrPart).toList
+    val insns = method.instructions.iterator.asScala.filter(i => textify(i) contains instrPart).toList
     if (useNext) insns.map(_.getNext) else insns
   }
 
diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/AnalyzerTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/AnalyzerTest.scala
new file mode 100644
index 0000000000..11014f5e64
--- /dev/null
+++ b/test/junit/scala/tools/nsc/backend/jvm/opt/AnalyzerTest.scala
@@ -0,0 +1,63 @@
+package scala.tools.nsc
+package backend.jvm
+package opt
+
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+import org.junit.Test
+import org.junit.Assert._
+
+import scala.tools.asm.tree._
+import scala.tools.asm.tree.analysis._
+import scala.tools.nsc.backend.jvm.analysis.{AliasingFrame, AliasingAnalyzer}
+
+import CodeGenTools._
+import scala.tools.partest.ASMConverters
+import ASMConverters._
+import AsmUtils._
+import BackendReporting._
+import BytecodeUtils._
+
+import scala.collection.convert.decorateAsScala._
+import scala.tools.testing.ClearAfterClass
+
+object AnalyzerTest extends ClearAfterClass.Clearable {
+  var noOptCompiler = newCompiler(extraArgs = "-Yopt:l:none")
+  def clear(): Unit = { noOptCompiler = null }
+}
+
+@RunWith(classOf[JUnit4])
+class AnalyzerTest extends ClearAfterClass {
+  ClearAfterClass.stateToClear = AnalyzerTest
+  val noOptCompiler = AnalyzerTest.noOptCompiler
+
+  @Test
+  def aliasingOfPrimitives(): Unit = {
+    val code =
+      """class C {
+        |  def f(a: Int, b: Long) = {
+        |    val c = a - b // a is converted with i2l
+        |    val d = c
+        |    val e = a
+        |    // locals: 0 this -- 1 a -- 2-3 b -- 4-5 c -- 6-7 d -- 8 e
+        |    e + d // e is converted with i2l
+        |  }
+        |}
+      """.stripMargin
+
+    val List(c) = compileClasses(noOptCompiler)(code)
+    val a = new AliasingAnalyzer(new BasicInterpreter)
+    val f = findAsmMethod(c, "f")
+    a.analyze("C", f)
+
+    val List(_, i2l) = findInstr(f, "I2L")
+    val aliasesAtI2l = a.frameAt(i2l, f).asInstanceOf[AliasingFrame[_]].aliases
+    assertEquals(aliasesAtI2l(1).iterator.toList, List(1, 8, 9)) // a, e and stack top
+    assertEquals(aliasesAtI2l(4).iterator.toList, List(4, 6))
+
+    val List(add) = findInstr(f, "LADD")
+    val aliasesAtAdd = a.frameAt(add, f).asInstanceOf[AliasingFrame[_]].aliases
+    assertEquals(aliasesAtAdd(1).iterator.toList, List(1, 8)) // after i2l the value on the stack is no longer an alias
+    assertEquals(aliasesAtAdd(4).iterator.toList, List(4, 6, 10)) // c, d and stack top
+  }
+}