From 658b62a4425ff7b774cd95e3323d9627b5af3c72 Mon Sep 17 00:00:00 2001
From: Jason Zaugg <jzaugg@gmail.com>
Date: Sun, 7 Jun 2015 12:51:51 +0200
Subject: Allow BCode to emit default interface methods

A DefDef owned by a trait may now have have a method body.
Such a method must be emitted without ACC_ABSTRACT, and
with the code attribute.

Tested by intercepting the compile pipeline and adding the
DEFAULTMETHOD flag and a method body before running
the backend.
---
 .../scala/tools/nsc/backend/jvm/CodeGenTools.scala | 17 +++++++++
 .../tools/nsc/backend/jvm/DefaultMethodTest.scala  | 43 ++++++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 test/junit/scala/tools/nsc/backend/jvm/DefaultMethodTest.scala

(limited to 'test/junit')

diff --git a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala
index ee9580c1c3..769236ae49 100644
--- a/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala
+++ b/test/junit/scala/tools/nsc/backend/jvm/CodeGenTools.scala
@@ -93,6 +93,23 @@ object CodeGenTools {
     getGeneratedClassfiles(compiler.settings.outputDirs.getSingleOutput.get)
   }
 
+  def compileTransformed(compiler: Global)(scalaCode: String, javaCode: List[(String, String)] = Nil, beforeBackend: compiler.Tree => compiler.Tree): List[(String, Array[Byte])] = {
+    compiler.settings.stopBefore.value = "jvm" :: Nil
+    val run = newRun(compiler)
+    import compiler._
+    val scalaUnit = newCompilationUnit(scalaCode, "unitTestSource.scala")
+    val javaUnits = javaCode.map(p => newCompilationUnit(p._1, p._2))
+    val units = scalaUnit :: javaUnits
+    run.compileUnits(units, run.parserPhase)
+    compiler.settings.stopBefore.value = Nil
+    scalaUnit.body = beforeBackend(scalaUnit.body)
+    checkReport(compiler, _ => false)
+    val run1 = newRun(compiler)
+    run1.compileUnits(units, run1.phaseNamed("jvm"))
+    checkReport(compiler, _ => false)
+    getGeneratedClassfiles(compiler.settings.outputDirs.getSingleOutput.get)
+  }
+
   /**
    * Compile multiple Scala files separately into a single output directory.
    *
diff --git a/test/junit/scala/tools/nsc/backend/jvm/DefaultMethodTest.scala b/test/junit/scala/tools/nsc/backend/jvm/DefaultMethodTest.scala
new file mode 100644
index 0000000000..f9a55bb26e
--- /dev/null
+++ b/test/junit/scala/tools/nsc/backend/jvm/DefaultMethodTest.scala
@@ -0,0 +1,43 @@
+package scala.tools.nsc.backend.jvm
+
+import org.junit.Assert._
+import org.junit.Test
+
+import scala.collection.JavaConverters
+import scala.tools.asm.Opcodes
+import scala.tools.asm.tree.ClassNode
+import scala.tools.nsc.backend.jvm.CodeGenTools._
+import JavaConverters._
+import scala.tools.testing.ClearAfterClass
+
+object DefaultMethodTest extends ClearAfterClass.Clearable {
+  var compiler = newCompiler(extraArgs = "-Ybackend:GenBCode")
+  def clear(): Unit = { compiler = null }
+}
+
+class DefaultMethodTest extends ClearAfterClass {
+  ClearAfterClass.stateToClear = DirectCompileTest
+  val compiler = DirectCompileTest.compiler
+
+  @Test
+  def defaultMethodsViaGenBCode(): Unit = {
+    import compiler._
+    val code = "package pack { trait T { def foo: Int }}"
+    object makeFooDefaultMethod extends Transformer {
+      val Foo = TermName("foo")
+      /** Transforms a single tree. */
+      override def transform(tree: compiler.Tree): compiler.Tree = tree match {
+        case dd @ DefDef(_, Foo, _, _, _, _) =>
+          dd.symbol.setFlag(reflect.internal.Flags.JAVA_DEFAULTMETHOD)
+          copyDefDef(dd)(rhs = Literal(Constant(1)).setType(definitions.IntTpe))
+        case _ => super.transform(tree)
+      }
+    }
+    val asmClasses: List[ClassNode] = readAsmClasses(compileTransformed(compiler)(code, Nil, makeFooDefaultMethod.transform(_)))
+    val foo = asmClasses.head.methods.iterator.asScala.toList.last
+    assertTrue("default method should not be abstract", (foo.access & Opcodes.ACC_ABSTRACT) == 0)
+    assertTrue("default method body emitted", foo.instructions.size() > 0)
+  }
+
+
+}
-- 
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