/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   https://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.bcel.verifier.structurals;
  
  import org.apache.bcel.Const;
  import org.apache.bcel.classfile.Constant;
  import org.apache.bcel.classfile.ConstantClass;
  import org.apache.bcel.classfile.ConstantDouble;
  import org.apache.bcel.classfile.ConstantDynamic;
  import org.apache.bcel.classfile.ConstantFloat;
  import org.apache.bcel.classfile.ConstantInteger;
  import org.apache.bcel.classfile.ConstantLong;
  import org.apache.bcel.classfile.ConstantString;
  // CHECKSTYLE:OFF (there are lots of references!)
  import org.apache.bcel.generic.*;
  //CHECKSTYLE:ON
  
  /**
   * This Visitor class may be used for a type-based Java Virtual Machine simulation.
   *
   * <p>
   * It does not check for correct types on the OperandStack or in the LocalVariables; nor does it check their sizes are
   * sufficiently big. Thus, to use this Visitor for bytecode verifying, you have to make sure externally that the type
   * constraints of the Java Virtual Machine instructions are satisfied. An InstConstraintVisitor may be used for this.
   * Anyway, this Visitor does not mandate it. For example, when you visitIADD(IADD o), then there are two stack slots
   * popped and one stack slot containing a Type.INT is pushed (where you could also pop only one slot if you know there
   * are two Type.INT on top of the stack). Monitor-specific behavior is not simulated.
   * </p>
   *
   * <strong>Conventions:</strong>
   *
   * <p>
   * Type.VOID will never be pushed onto the stack. Type.DOUBLE and Type.LONG that would normally take up two stack slots
   * (like Double_HIGH and Double_LOW) are represented by a simple single Type.DOUBLE or Type.LONG object on the stack
   * here.
   * </p>
   *
   * <p>
   * If a two-slot type is stored into a local variable, the next variable is given the type Type.UNKNOWN.
   * </p>
   *
   * @see #visitDSTORE(DSTORE o)
   * @see InstConstraintVisitor
   */
  public class ExecutionVisitor extends EmptyVisitor {
  
      /**
       * The executionframe we're operating on.
       */
      private Frame frame;
  
      /**
       * The ConstantPoolGen we're working with.
       *
       * @see #setConstantPoolGen(ConstantPoolGen)
       */
      private ConstantPoolGen cpg;
  
      /**
       * Constructs a new instance of this class.
       */
      public ExecutionVisitor() {
      }
  
      /**
       * The LocalVariables from the current Frame we're operating on.
       *
       * @see #setFrame(Frame)
       */
      private LocalVariables locals() {
          return frame.getLocals();
      }
  
      /**
       * Sets the ConstantPoolGen needed for symbolic execution.
       *
       * @param cpg the constant pool generator.
       */
      public void setConstantPoolGen(final ConstantPoolGen cpg) { // TODO could be package-protected?
          this.cpg = cpg;
      }
  
      /**
      * The only method granting access to the single instance of the ExecutionVisitor class. Before actively using this
      * instance, <strong>SET THE ConstantPoolGen FIRST</strong>.
      *
      * @param f the frame.
      * @see #setConstantPoolGen(ConstantPoolGen)
      */
     public void setFrame(final Frame f) { // TODO could be package-protected?
         this.frame = f;
     }
 
     /**
      * The OperandStack from the current Frame we're operating on.
      *
      * @see #setFrame(Frame)
      */
     private OperandStack stack() {
         return frame.getStack();
     }
 
     /// ** Symbolically executes the corresponding Java Virtual Machine instruction. */
     // public void visitWIDE(WIDE o) {
     // The WIDE instruction is modeled as a flag
     // of the embedded instructions in BCEL.
     // Therefore BCEL checks for possible errors
     // when parsing in the .class file: We don't
     // have even the possibility to care for WIDE
     // here.
     // }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitAALOAD(final AALOAD o) {
         stack().pop(); // pop the index int
         // System.out.print(stack().peek());
         final Type t = stack().pop(); // Pop Array type
         if (t == Type.NULL) {
             stack().push(Type.NULL);
         } else {
             final ArrayType at = (ArrayType) t;
             stack().push(at.getElementType());
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitAASTORE(final AASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitACONST_NULL(final ACONST_NULL o) {
         stack().push(Type.NULL);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitALOAD(final ALOAD o) {
         stack().push(locals().get(o.getIndex()));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitANEWARRAY(final ANEWARRAY o) {
         stack().pop(); // count
         stack().push(new ArrayType(o.getType(cpg), 1));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitARETURN(final ARETURN o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitARRAYLENGTH(final ARRAYLENGTH o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitASTORE(final ASTORE o) {
         locals().set(o.getIndex(), stack().pop());
         // System.err.println("TODO-DEBUG: set LV '"+o.getIndex()+"' to '"+locals().get(o.getIndex())+"'.");
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitATHROW(final ATHROW o) {
         final Type t = stack().pop();
         stack().clear();
         if (t.equals(Type.NULL)) {
             stack().push(Type.getType("Ljava/lang/NullPointerException;"));
         } else {
             stack().push(t);
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitBALOAD(final BALOAD o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitBASTORE(final BASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitBIPUSH(final BIPUSH o) {
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitCALOAD(final CALOAD o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitCASTORE(final CASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitCHECKCAST(final CHECKCAST o) {
         // It's possibly wrong to do so, but SUN's
         // ByteCode verifier seems to do (only) this, too.
         // TODO: One could use a sophisticated analysis here to check
         // if a type cannot possibly be cated to another and by
         // so doing predict the ClassCastException at run-time.
         stack().pop();
         stack().push(o.getType(cpg));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitD2F(final D2F o) {
         stack().pop();
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitD2I(final D2I o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitD2L(final D2L o) {
         stack().pop();
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDADD(final DADD o) {
         stack().pop(2);
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDALOAD(final DALOAD o) {
         stack().pop(2);
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDASTORE(final DASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDCMPG(final DCMPG o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDCMPL(final DCMPL o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDCONST(final DCONST o) {
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDDIV(final DDIV o) {
         stack().pop(2);
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDLOAD(final DLOAD o) {
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDMUL(final DMUL o) {
         stack().pop(2);
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDNEG(final DNEG o) {
         stack().pop();
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDREM(final DREM o) {
         stack().pop(2);
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDRETURN(final DRETURN o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDSTORE(final DSTORE o) {
         locals().set(o.getIndex(), stack().pop());
         locals().set(o.getIndex() + 1, Type.UNKNOWN);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDSUB(final DSUB o) {
         stack().pop(2);
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDUP(final DUP o) {
         final Type t = stack().pop();
         stack().push(t);
         stack().push(t);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDUP_X1(final DUP_X1 o) {
         final Type w1 = stack().pop();
         final Type w2 = stack().pop();
         stack().push(w1);
         stack().push(w2);
         stack().push(w1);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDUP_X2(final DUP_X2 o) {
         final Type w1 = stack().pop();
         final Type w2 = stack().pop();
         if (w2.getSize() == 2) {
             stack().push(w1);
         } else {
             final Type w3 = stack().pop();
             stack().push(w1);
             stack().push(w3);
         }
         stack().push(w2);
         stack().push(w1);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDUP2(final DUP2 o) {
         final Type t = stack().pop();
         if (t.getSize() == 2) {
             stack().push(t);
         } else { // t.getSize() is 1
             final Type u = stack().pop();
             stack().push(u);
             stack().push(t);
             stack().push(u);
         }
         stack().push(t);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDUP2_X1(final DUP2_X1 o) {
         final Type t = stack().pop();
         if (t.getSize() == 2) {
             final Type u = stack().pop();
             stack().push(t);
             stack().push(u);
         } else { // t.getSize() is1
             final Type u = stack().pop();
             final Type v = stack().pop();
             stack().push(u);
             stack().push(t);
             stack().push(v);
             stack().push(u);
         }
         stack().push(t);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitDUP2_X2(final DUP2_X2 o) {
         final Type t = stack().pop();
         if (t.getSize() == 2) {
             final Type u = stack().pop();
             if (u.getSize() == 2) {
                 stack().push(t);
             } else {
                 final Type v = stack().pop();
                 stack().push(t);
                 stack().push(v);
             }
             stack().push(u);
         } else { // t.getSize() is 1
             final Type u = stack().pop();
             final Type v = stack().pop();
             if (v.getSize() == 2) {
                 stack().push(u);
                 stack().push(t);
             } else {
                 final Type w = stack().pop();
                 stack().push(u);
                 stack().push(t);
                 stack().push(w);
             }
             stack().push(v);
             stack().push(u);
         }
         stack().push(t);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitF2D(final F2D o) {
         stack().pop();
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitF2I(final F2I o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitF2L(final F2L o) {
         stack().pop();
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFADD(final FADD o) {
         stack().pop(2);
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFALOAD(final FALOAD o) {
         stack().pop(2);
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFASTORE(final FASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFCMPG(final FCMPG o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFCMPL(final FCMPL o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFCONST(final FCONST o) {
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFDIV(final FDIV o) {
         stack().pop(2);
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFLOAD(final FLOAD o) {
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFMUL(final FMUL o) {
         stack().pop(2);
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFNEG(final FNEG o) {
         stack().pop();
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFREM(final FREM o) {
         stack().pop(2);
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFRETURN(final FRETURN o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFSTORE(final FSTORE o) {
         locals().set(o.getIndex(), stack().pop());
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitFSUB(final FSUB o) {
         stack().pop(2);
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitGETFIELD(final GETFIELD o) {
         stack().pop();
         Type t = o.getFieldType(cpg);
         if (t.equals(Type.BOOLEAN) || t.equals(Type.CHAR) || t.equals(Type.BYTE) || t.equals(Type.SHORT)) {
             t = Type.INT;
         }
         stack().push(t);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitGETSTATIC(final GETSTATIC o) {
         Type t = o.getFieldType(cpg);
         if (t.equals(Type.BOOLEAN) || t.equals(Type.CHAR) || t.equals(Type.BYTE) || t.equals(Type.SHORT)) {
             t = Type.INT;
         }
         stack().push(t);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitGOTO(final GOTO o) {
         // no stack changes.
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitGOTO_W(final GOTO_W o) {
         // no stack changes.
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitI2B(final I2B o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitI2C(final I2C o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitI2D(final I2D o) {
         stack().pop();
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitI2F(final I2F o) {
         stack().pop();
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitI2L(final I2L o) {
         stack().pop();
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitI2S(final I2S o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIADD(final IADD o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIALOAD(final IALOAD o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIAND(final IAND o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIASTORE(final IASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitICONST(final ICONST o) {
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIDIV(final IDIV o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ACMPEQ(final IF_ACMPEQ o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ACMPNE(final IF_ACMPNE o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ICMPEQ(final IF_ICMPEQ o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ICMPGE(final IF_ICMPGE o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ICMPGT(final IF_ICMPGT o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ICMPLE(final IF_ICMPLE o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ICMPLT(final IF_ICMPLT o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIF_ICMPNE(final IF_ICMPNE o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFEQ(final IFEQ o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFGE(final IFGE o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFGT(final IFGT o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFLE(final IFLE o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFLT(final IFLT o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFNE(final IFNE o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFNONNULL(final IFNONNULL o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIFNULL(final IFNULL o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIINC(final IINC o) {
         // stack is not changed.
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitILOAD(final ILOAD o) {
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIMUL(final IMUL o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitINEG(final INEG o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitINSTANCEOF(final INSTANCEOF o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     private void visitInvokedInternals(final InvokeInstruction o) {
         stack().pop(o.getArgumentTypes(cpg).length);
         // We are sure the invoked method will xRETURN eventually
         // We simulate xRETURNs functionality here because we
         // don't really "jump into" and simulate the invoked
         // method.
         if (o.getReturnType(cpg) != Type.VOID) {
             Type t = o.getReturnType(cpg);
             if (t.equals(Type.BOOLEAN) || t.equals(Type.CHAR) || t.equals(Type.BYTE) || t.equals(Type.SHORT)) {
                 t = Type.INT;
             }
             stack().push(t);
         }
     }
 
     /**
      * Symbolically executes the corresponding Java Virtual Machine instruction.
      *
      * @since 6.0
      */
     @Override
     public void visitINVOKEDYNAMIC(final INVOKEDYNAMIC o) {
         visitInvokedInternals(o);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitINVOKEINTERFACE(final INVOKEINTERFACE o) {
         stack().pop(); // objectref
         stack().pop(o.getArgumentTypes(cpg).length);
         // We are sure the invoked method will xRETURN eventually
         // We simulate xRETURNs functionality here because we
         // don't really "jump into" and simulate the invoked
         // method.
         if (o.getReturnType(cpg) != Type.VOID) {
             Type t = o.getReturnType(cpg);
             if (t.equals(Type.BOOLEAN) || t.equals(Type.CHAR) || t.equals(Type.BYTE) || t.equals(Type.SHORT)) {
                 t = Type.INT;
             }
             stack().push(t);
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitINVOKESPECIAL(final INVOKESPECIAL o) {
         if (o.getMethodName(cpg).equals(Const.CONSTRUCTOR_NAME)) {
             final UninitializedObjectType t = (UninitializedObjectType) stack().peek(o.getArgumentTypes(cpg).length);
             if (t == Frame.getThis()) {
                 Frame.setThis(null);
             }
             stack().initializeObject(t);
             locals().initializeObject(t);
         }
         stack().pop(); // objectref
         stack().pop(o.getArgumentTypes(cpg).length);
         // We are sure the invoked method will xRETURN eventually
         // We simulate xRETURNs functionality here because we
         // don't really "jump into" and simulate the invoked
         // method.
         if (o.getReturnType(cpg) != Type.VOID) {
             Type t = o.getReturnType(cpg);
             if (t.equals(Type.BOOLEAN) || t.equals(Type.CHAR) || t.equals(Type.BYTE) || t.equals(Type.SHORT)) {
                 t = Type.INT;
             }
             stack().push(t);
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitINVOKESTATIC(final INVOKESTATIC o) {
         visitInvokedInternals(o);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitINVOKEVIRTUAL(final INVOKEVIRTUAL o) {
         stack().pop(); // objectref
         stack().pop(o.getArgumentTypes(cpg).length);
         // We are sure the invoked method will xRETURN eventually
         // We simulate xRETURNs functionality here because we
         // don't really "jump into" and simulate the invoked
         // method.
         if (o.getReturnType(cpg) != Type.VOID) {
             Type t = o.getReturnType(cpg);
             if (t.equals(Type.BOOLEAN) || t.equals(Type.CHAR) || t.equals(Type.BYTE) || t.equals(Type.SHORT)) {
                 t = Type.INT;
             }
             stack().push(t);
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIOR(final IOR o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIREM(final IREM o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIRETURN(final IRETURN o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitISHL(final ISHL o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitISHR(final ISHR o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitISTORE(final ISTORE o) {
         locals().set(o.getIndex(), stack().pop());
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitISUB(final ISUB o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIUSHR(final IUSHR o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitIXOR(final IXOR o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitJSR(final JSR o) {
         stack().push(new ReturnaddressType(o.physicalSuccessor()));
 //System.err.println("TODO-----------:"+o.physicalSuccessor());
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitJSR_W(final JSR_W o) {
         stack().push(new ReturnaddressType(o.physicalSuccessor()));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitL2D(final L2D o) {
         stack().pop();
         stack().push(Type.DOUBLE);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitL2F(final L2F o) {
         stack().pop();
         stack().push(Type.FLOAT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitL2I(final L2I o) {
         stack().pop();
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLADD(final LADD o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLALOAD(final LALOAD o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLAND(final LAND o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLASTORE(final LASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLCMP(final LCMP o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLCONST(final LCONST o) {
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLDC(final LDC o) {
         final Constant c = cpg.getConstant(o.getIndex());
         if (c instanceof ConstantInteger) {
             stack().push(Type.INT);
         }
         if (c instanceof ConstantFloat) {
             stack().push(Type.FLOAT);
         }
         if (c instanceof ConstantString) {
             stack().push(Type.STRING);
         }
         if (c instanceof ConstantClass) {
             stack().push(Type.CLASS);
         }
         if (c instanceof ConstantDynamic) {
             stack().push(Type.OBJECT);
         }
     }
 
     /**
      * Symbolically executes the corresponding Java Virtual Machine instruction.
      *
      * @param o the instruction.
      */
     public void visitLDC_W(final LDC_W o) {
         final Constant c = cpg.getConstant(o.getIndex());
         if (c instanceof ConstantInteger) {
             stack().push(Type.INT);
         }
         if (c instanceof ConstantFloat) {
             stack().push(Type.FLOAT);
         }
         if (c instanceof ConstantString) {
             stack().push(Type.STRING);
         }
         if (c instanceof ConstantClass) {
             stack().push(Type.CLASS);
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLDC2_W(final LDC2_W o) {
         final Constant c = cpg.getConstant(o.getIndex());
         if (c instanceof ConstantLong) {
             stack().push(Type.LONG);
         }
         if (c instanceof ConstantDouble) {
             stack().push(Type.DOUBLE);
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLDIV(final LDIV o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLLOAD(final LLOAD o) {
         stack().push(locals().get(o.getIndex()));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLMUL(final LMUL o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLNEG(final LNEG o) {
         stack().pop();
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLOOKUPSWITCH(final LOOKUPSWITCH o) {
         stack().pop(); // key
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLOR(final LOR o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLREM(final LREM o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLRETURN(final LRETURN o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLSHL(final LSHL o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLSHR(final LSHR o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLSTORE(final LSTORE o) {
         locals().set(o.getIndex(), stack().pop());
         locals().set(o.getIndex() + 1, Type.UNKNOWN);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLSUB(final LSUB o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLUSHR(final LUSHR o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitLXOR(final LXOR o) {
         stack().pop(2);
         stack().push(Type.LONG);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitMONITORENTER(final MONITORENTER o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitMONITOREXIT(final MONITOREXIT o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitMULTIANEWARRAY(final MULTIANEWARRAY o) {
         stack().pop(o.getDimensions());
         stack().push(o.getType(cpg));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitNEW(final NEW o) {
         stack().push(new UninitializedObjectType((ObjectType) o.getType(cpg)));
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitNEWARRAY(final NEWARRAY o) {
         stack().pop();
         stack().push(o.getType());
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitNOP(final NOP o) {
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitPOP(final POP o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitPOP2(final POP2 o) {
         final Type t = stack().pop();
         if (t.getSize() == 1) {
             stack().pop();
         }
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitPUTFIELD(final PUTFIELD o) {
         stack().pop(2);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitPUTSTATIC(final PUTSTATIC o) {
         stack().pop();
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitRET(final RET o) {
         // do nothing, return address
         // is in the local variables.
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitRETURN(final RETURN o) {
         // do nothing.
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitSALOAD(final SALOAD o) {
         stack().pop(2);
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitSASTORE(final SASTORE o) {
         stack().pop(3);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitSIPUSH(final SIPUSH o) {
         stack().push(Type.INT);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitSWAP(final SWAP o) {
         final Type t = stack().pop();
         final Type u = stack().pop();
         stack().push(t);
         stack().push(u);
     }
 
     /** Symbolically executes the corresponding Java Virtual Machine instruction. */
     @Override
     public void visitTABLESWITCH(final TABLESWITCH o) {
         stack().pop();
     }
 }