diff options
Diffstat (limited to 'test')
-rw-r--r-- | test/files/jvm/bytecode-test-example.check | 1 | ||||
-rw-r--r-- | test/files/jvm/bytecode-test-example/Foo_1.scala | 9 | ||||
-rw-r--r-- | test/files/jvm/bytecode-test-example/Test.scala | 32 |
3 files changed, 42 insertions, 0 deletions
diff --git a/test/files/jvm/bytecode-test-example.check b/test/files/jvm/bytecode-test-example.check new file mode 100644 index 0000000000..0cfbf08886 --- /dev/null +++ b/test/files/jvm/bytecode-test-example.check @@ -0,0 +1 @@ +2 diff --git a/test/files/jvm/bytecode-test-example/Foo_1.scala b/test/files/jvm/bytecode-test-example/Foo_1.scala new file mode 100644 index 0000000000..4f679d156f --- /dev/null +++ b/test/files/jvm/bytecode-test-example/Foo_1.scala @@ -0,0 +1,9 @@ +class Foo_1 { + def foo(x: AnyRef): Int = { + val bool = x == null + if (x != null) + 1 + else + 0 + } +} diff --git a/test/files/jvm/bytecode-test-example/Test.scala b/test/files/jvm/bytecode-test-example/Test.scala new file mode 100644 index 0000000000..d668059cb7 --- /dev/null +++ b/test/files/jvm/bytecode-test-example/Test.scala @@ -0,0 +1,32 @@ +import scala.tools.partest.BytecodeTest + +import scala.tools.nsc.util.JavaClassPath +import java.io.InputStream +import scala.tools.asm +import asm.ClassReader +import asm.tree.{ClassNode, InsnList} +import scala.collection.JavaConverters._ + +object Test extends BytecodeTest { + def show: Unit = { + val classNode = loadClassNode("Foo_1") + val methodNode = getMethod(classNode, "foo") + println(countNullChecks(methodNode.instructions)) + } + + def countNullChecks(insnList: InsnList): Int = { + /** Is given instruction a null check? + * NOTE + * This will detect direct null compparsion as in + * if (x == null) ... + * and not indirect as in + * val foo = null + * if (x == foo) ... + */ + def isNullCheck(node: asm.tree.AbstractInsnNode): Boolean = { + val opcode = node.getOpcode + (opcode == asm.Opcodes.IFNULL) || (opcode == asm.Opcodes.IFNONNULL) + } + insnList.iterator.asScala.count(isNullCheck) + } +} |