gt:         Label l1 = new Label();
context: /*
   * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package org.graalvm.compiler.core.test;
  
  import jdk.vm.ci.code.BailoutException;
  import jdk.vm.ci.meta.ResolvedJavaMethod;
  import org.objectweb.asm.ClassWriter;
  import org.objectweb.asm.Label;
  import org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.Opcodes;
  
  import static org.graalvm.compiler.core.common.CompilationIdentifier.INVALID_COMPILATION_ID;
  
  import org.junit.Test;
  
  import org.graalvm.compiler.java.GraphBuilderPhase;
  import org.graalvm.compiler.nodes.StructuredGraph;
  import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;
  import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;
  import org.graalvm.compiler.nodes.graphbuilderconf.InvocationPlugins;
  import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration.Plugins;
  import org.graalvm.compiler.phases.OptimisticOptimizations;
  
  /**
   * Exercise handling of unbalanced monitor operations by the parser. Algorithmically Graal assumes
   * that locks are statically block structured but that isn't something enforced by the bytecodes. In
   * HotSpot a dataflow is performed to ensure they are properly structured and methods with
   * unstructured locking aren't compiled and fall back to the interpreter. Having the Graal parser
   * handle this directly is simplifying for targets of Graal since they don't have to provide a data
   * flow that checks this property.
   */
  public class UnbalancedMonitorsTest extends GraalCompilerTest implements Opcodes {
      private static final String CLASS_NAME = UnbalancedMonitorsTest.class.getName();
      private static final String INNER_CLASS_NAME = CLASS_NAME + "$UnbalancedMonitors";
      private static final String CLASS_NAME_INTERNAL = CLASS_NAME.replace('.', '/');
      private static final String INNER_CLASS_NAME_INTERNAL = INNER_CLASS_NAME.replace('.', '/');
  
      private static AsmLoader LOADER = new AsmLoader(UnbalancedMonitorsTest.class.getClassLoader());
  
      @Test
      public void runWrongOrder() throws Exception {
          checkForBailout("wrongOrder");
      }
  
      @Test
      public void runTooFewExits() throws Exception {
          checkForBailout("tooFewExits");
      }
  
      @Test
      public void runTooManyExits() throws Exception {
          checkForBailout("tooManyExits");
      }
  
      @Test
      public void runTooFewExitsExceptional() throws Exception {
          checkForBailout("tooFewExitsExceptional");
      }
  
      @Test
      public void runTooManyExitsExceptional() throws Exception {
          checkForBailout("tooManyExitsExceptional");
      }
  
      private void checkForBailout(String name) throws ClassNotFoundException {
          ResolvedJavaMethod method = getResolvedJavaMethod(LOADER.findClass(INNER_CLASS_NAME), name);
          try {
              StructuredGraph graph = new StructuredGraph(method, AllowAssumptions.NO, INVALID_COMPILATION_ID);
              Plugins plugins = new Plugins(new InvocationPlugins());
              GraphBuilderConfiguration graphBuilderConfig = GraphBuilderConfiguration.getDefault(plugins).withEagerResolving(true);
              OptimisticOptimizations optimisticOpts = OptimisticOptimizations.NONE;
  
              GraphBuilderPhase.Instance graphBuilder = new GraphBuilderPhase.Instance(getMetaAccess(), getProviders().getStampProvider(), null, null, graphBuilderConfig, optimisticOpts, null);
              graphBuilder.apply(graph);
          } catch (BailoutException e) {
              if (e.getMessage().contains("unbalanced monitors")) {
                  return;
              }
              throw e;
          }
          assertTrue("should have bailed out", false);
      }
  
      // @formatter:off
      // Template class used with Bytecode Outline to generate ASM code
      //    public static class UnbalancedMonitors {
      //
      //        public UnbalancedMonitors() {
      //        }
      //
      //        public Object wrongOrder(Object a, Object b) {
      //            synchronized (a) {
      //                synchronized (b) {
      //                    return b;
      //                }
      //            }
      //        }
      //
      //        public Object tooFewExits(Object a, Object b) {
      //            synchronized (a) {
      //                synchronized (b) {
      //                    return b;
      //                }
      //            }
      //        }
      //
      //        public boolean tooFewExitsExceptional(Object a, Object b) {
      //            synchronized (a) {
      //                synchronized (b) {
      //                    return b.equals(a);
      //                }
      //            }
      //        }
      //    }
      // @formatter:on
  
      public static byte[] generateClass() {
  
          ClassWriter cw = new ClassWriter(0);
  
          cw.visit(52, ACC_SUPER | ACC_PUBLIC, INNER_CLASS_NAME_INTERNAL, null, "java/lang/Object", null);
  
          cw.visitSource("UnbalancedMonitorsTest.java", null);
  
          cw.visitInnerClass(INNER_CLASS_NAME_INTERNAL, CLASS_NAME_INTERNAL, "UnbalancedMonitors", ACC_STATIC);
  
          visitConstructor(cw);
          visitWrongOrder(cw);
          visitBlockStructured(cw, true, false);
          visitBlockStructured(cw, true, true);
          visitBlockStructured(cw, false, false);
          visitBlockStructured(cw, false, true);
          cw.visitEnd();
  
          return cw.toByteArray();
      }
  
      private static void visitBlockStructured(ClassWriter cw, boolean normalReturnError, boolean tooMany) {
          String name = (tooMany ? "tooMany" : "tooFew") + "Exits" + (normalReturnError ? "" : "Exceptional");
          // Generate too many or too few exits down the either the normal or exceptional return paths
          int exceptionalExitCount = normalReturnError ? 1 : (tooMany ? 2 : 0);
          int normalExitCount = normalReturnError ? (tooMany ? 2 : 0) : 1;
          MethodVisitor mv;
          mv = cw.visitMethod(ACC_PUBLIC, name, "(Ljava/lang/Object;Ljava/lang/Object;)Z", null, null);
          mv.visitCode();
          Label l0 = new Label();
          Label l1 = new Label();
          Label l2 = new Label();
          mv.visitTryCatchBlock(l0, l1, l2, null);
          Label l3 = new Label();
          mv.visitTryCatchBlock(l2, l3, l2, null);
          Label l4 = new Label();
          Label l5 = new Label();
          Label l6 = new Label();
          mv.visitTryCatchBlock(l4, l5, l6, null);
          Label l7 = new Label();
          mv.visitTryCatchBlock(l2, l7, l6, null);
          Label l8 = new Label();
          mv.visitLabel(l8);
          mv.visitVarInsn(ALOAD, 1);
          mv.visitInsn(DUP);
          mv.visitVarInsn(ASTORE, 3);
          mv.visitInsn(MONITORENTER);
          mv.visitLabel(l4);
          mv.visitVarInsn(ALOAD, 2);
          mv.visitInsn(DUP);
          mv.visitVarInsn(ASTORE, 4);
          mv.visitInsn(MONITORENTER);
          mv.visitLabel(l0);
          mv.visitVarInsn(ALOAD, 2);
          mv.visitVarInsn(ALOAD, 1);
          mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "equals", "(Ljava/lang/Object;)Z", false);
          mv.visitVarInsn(ALOAD, 4);
          mv.visitInsn(MONITOREXIT);
          mv.visitLabel(l1);
          for (int i = 0; i < normalExitCount; i++) {
              mv.visitVarInsn(ALOAD, 3);
              mv.visitInsn(MONITOREXIT);
          }
          mv.visitLabel(l5);
          mv.visitInsn(IRETURN);
          mv.visitLabel(l2);
          mv.visitFrame(Opcodes.F_FULL, 5, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object",
                          "java/lang/Object"}, 1, new Object[]{"java/lang/Throwable"});
          mv.visitVarInsn(ALOAD, 4);
          mv.visitInsn(MONITOREXIT);
          mv.visitLabel(l3);
          mv.visitInsn(ATHROW);
          mv.visitLabel(l6);
          mv.visitFrame(Opcodes.F_FULL, 4, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object"}, 1,
                          new Object[]{"java/lang/Throwable"});
          for (int i = 0; i < exceptionalExitCount; i++) {
              mv.visitVarInsn(ALOAD, 3);
              mv.visitInsn(MONITOREXIT);
          }
          mv.visitLabel(l7);
          mv.visitInsn(ATHROW);
          Label l9 = new Label();
          mv.visitLabel(l9);
          mv.visitMaxs(2, 5);
          mv.visitEnd();
      }
  
      private static void visitWrongOrder(ClassWriter cw) {
          MethodVisitor mv;
          mv = cw.visitMethod(ACC_PUBLIC, "wrongOrder", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;", null, null);
          mv.visitCode();
          Label l0 = new Label();
          Label l1 = new Label();
          Label l2 = new Label();
          mv.visitTryCatchBlock(l0, l1, l2, null);
          Label l3 = new Label();
          mv.visitTryCatchBlock(l2, l3, l2, null);
          Label l4 = new Label();
          Label l5 = new Label();
          Label l6 = new Label();
          mv.visitTryCatchBlock(l4, l5, l6, null);
          Label l7 = new Label();
          mv.visitTryCatchBlock(l2, l7, l6, null);
          Label l8 = new Label();
          mv.visitLabel(l8);
          mv.visitVarInsn(ALOAD, 1);
          mv.visitInsn(DUP);
          mv.visitVarInsn(ASTORE, 3);
          mv.visitInsn(MONITORENTER);
          mv.visitLabel(l4);
          mv.visitVarInsn(ALOAD, 2);
          mv.visitInsn(DUP);
          mv.visitVarInsn(ASTORE, 4);
          mv.visitInsn(MONITORENTER);
          mv.visitLabel(l0);
          mv.visitVarInsn(ALOAD, 2);
          mv.visitVarInsn(ALOAD, 3);
          mv.visitInsn(MONITOREXIT);
          mv.visitLabel(l1);
          // Swapped exit order with exit above
          mv.visitVarInsn(ALOAD, 4);
          mv.visitInsn(MONITOREXIT);
          mv.visitLabel(l5);
          mv.visitInsn(ARETURN);
          mv.visitLabel(l2);
          mv.visitFrame(Opcodes.F_FULL, 5, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object",
                          "java/lang/Object"}, 1, new Object[]{"java/lang/Throwable"});
          mv.visitVarInsn(ALOAD, 4);
          mv.visitInsn(MONITOREXIT);
          mv.visitLabel(l3);
          mv.visitInsn(ATHROW);
          mv.visitLabel(l6);
          mv.visitFrame(Opcodes.F_FULL, 4, new Object[]{INNER_CLASS_NAME_INTERNAL, "java/lang/Object", "java/lang/Object", "java/lang/Object"}, 1,
                          new Object[]{"java/lang/Throwable"});
          mv.visitVarInsn(ALOAD, 3);
          mv.visitInsn(MONITOREXIT);
          mv.visitLabel(l7);
          mv.visitInsn(ATHROW);
          Label l9 = new Label();
          mv.visitLabel(l9);
          mv.visitMaxs(2, 5);
          mv.visitEnd();
      }
  
      private static void visitConstructor(ClassWriter cw) {
          MethodVisitor mv;
          mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
          mv.visitCode();
          Label l0 = new Label();
          mv.visitLabel(l0);
          mv.visitVarInsn(ALOAD, 0);
          mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
  