Reuse the same compiler instance for all tests in a JUnit class

Note that JUnit creates a new instance of the test class for running
each test method. So the compiler instance is added to the companion.
However, the JVM would quickly run out of memory when running multiple
tests, as the compilers cannot be GCd. So we make it a `var`, and set
it to null when a class is done. For that we use JUnit's `@AfterClass`
which is required to be on a static method. Therefore we add a Java
class with such a static method that we can extend from Scala.

1 files changed, 10 insertions, 2 deletions

diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala
index 5430e33d6c..2c71e9d533 100644
--- a/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala
+++ b/test/junit/scala/tools/nsc/backend/jvm/opt/MethodLevelOpts.scala
@@ -13,10 +13,18 @@ import scala.tools.testing.AssertUtil._
 import CodeGenTools._
 import scala.tools.partest.ASMConverters
 import ASMConverters._
+import scala.tools.testing.ClearAfterClass
+
+object MethodLevelOpts extends ClearAfterClass.Clearable {
+  var methodOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:l:method")
+  def clear(): Unit = { methodOptCompiler = null }
+}
 
 @RunWith(classOf[JUnit4])
-class MethodLevelOpts {
-  val methodOptCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:l:method")
+class MethodLevelOpts extends ClearAfterClass {
+  ClearAfterClass.stateToClear = MethodLevelOpts
+
+  val methodOptCompiler = MethodLevelOpts.methodOptCompiler
 
   def wrapInDefault(code: Instruction*) = List(Label(0), LineNumber(1, Label(0))) ::: code.toList ::: List(Label(1))