tests/org.simantics.scl.compiler.tests/src/org/simantics/scl/compiler/tests/experimentation/RecursiveInitialization.java

   1 package org.simantics.scl.compiler.tests.experimentation;
   2
   3 import java.io.PrintWriter;
   4 import java.lang.reflect.Method;
   5 import java.util.concurrent.atomic.AtomicReference;
   6
   7 import org.objectweb.asm.ClassVisitor;
   8 import org.objectweb.asm.ClassWriter;
   9 import org.objectweb.asm.MethodVisitor;
  10 import org.objectweb.asm.Opcodes;
  11 import org.objectweb.asm.util.TraceClassVisitor;
  12
  13 public class RecursiveInitialization {
  14
  15     public static void main(String[] args) throws Exception {
  16         ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS);
  17         ClassVisitor classVisitor = new TraceClassVisitor(classWriter, new PrintWriter(System.out));
  18         classVisitor.visit(Opcodes.V1_5, Opcodes.ACC_PUBLIC, "test/Test", null, "java/lang/Object", new String[0]);
  19         MethodVisitor methodWriter = classVisitor.visitMethod(
  20                 Opcodes.ACC_PUBLIC | Opcodes.ACC_STATIC,
  21                 "main", "()Ljava/lang/Object;", null, null);
  22
  23         methodWriter.visitCode();
  24         methodWriter.visitTypeInsn(Opcodes.NEW, "java/util/concurrent/atomic/AtomicReference");
  25         methodWriter.visitVarInsn(Opcodes.ASTORE, 2);
  26
  27         methodWriter.visitTypeInsn(Opcodes.NEW, "java/util/concurrent/atomic/AtomicReference");
  28         methodWriter.visitVarInsn(Opcodes.ASTORE, 1);
  29
  30         methodWriter.visitVarInsn(Opcodes.ALOAD, 2);
  31         methodWriter.visitVarInsn(Opcodes.ALOAD, 1);
  32         //methodWriter.visitInsn(Opcodes.ACONST_NULL);
  33         methodWriter.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/util/concurrent/atomic/AtomicReference", "<init>", "(Ljava/lang/Object;)V", false);
  34
  35         methodWriter.visitVarInsn(Opcodes.ALOAD, 1);
  36         methodWriter.visitVarInsn(Opcodes.ALOAD, 2);
  37         methodWriter.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/util/concurrent/atomic/AtomicReference", "<init>", "(Ljava/lang/Object;)V", false);
  38
  39         methodWriter.visitVarInsn(Opcodes.ALOAD, 2);
  40         methodWriter.visitInsn(Opcodes.ARETURN);
  41         methodWriter.visitMaxs(0, 0);
  42         methodWriter.visitEnd();
  43
  44         byte[] bytes = classWriter.toByteArray();
  45         ClassLoader classLoader = new ClassLoader() {
  46             @Override
  47             protected Class<?> findClass(String name) throws ClassNotFoundException {
  48                 if(!name.equals("test.Test"))
  49                     throw new ClassNotFoundException();
  50                 return defineClass("test.Test", bytes, 0, bytes.length);
  51             }
  52         };
  53         Class<?> clazz = classLoader.loadClass("test.Test");
  54         Method method = clazz.getMethod("main");
  55         AtomicReference<Object> result = (AtomicReference<Object>)method.invoke(null);
  56         System.out.println(result.hashCode());
  57         //System.out.println(result.get().hashCode());
  58     }
  59
  60 }