// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. Neither the name of the copyright holders nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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package org.objectweb.asm.commons;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.objectweb.asm.ConstantDynamic;
import org.objectweb.asm.Handle;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

A MethodVisitor that keeps track of stack map frame changes between visitFrame(int, int, Object[], int, Object[]) calls. This adapter must be used with the ClassReader.EXPAND_FRAMES option. Each visitX instruction delegates to the next visitor in the chain, if any, and then simulates the effect of this instruction on the stack map frame, represented by locals and stack. The next visitor in the chain can get the state of the stack map frame before each instruction by reading the value of
these fields in its visitX methods (this requires a reference to the AnalyzerAdapter that is before it in the chain). If this adapter is used with a class that does not contain stack map table attributes (i.e., pre Java 6 classes) then this adapter may not be able to compute the stack map frame for each instruction. In this case no exception is thrown but the locals and stack fields will be null for these instructions. 
Author:
Eric Bruneton/**
 * A {@link MethodVisitor} that keeps track of stack map frame changes between {@link
 * #visitFrame(int, int, Object[], int, Object[])} calls. This adapter must be used with the {@link
 * org.objectweb.asm.ClassReader#EXPAND_FRAMES} option. Each visit<i>X</i> instruction delegates to
 * the next visitor in the chain, if any, and then simulates the effect of this instruction on the
 * stack map frame, represented by {@link #locals} and {@link #stack}. The next visitor in the chain
 * can get the state of the stack map frame <i>before</i> each instruction by reading the value of
 * these fields in its visit<i>X</i> methods (this requires a reference to the AnalyzerAdapter that
 * is before it in the chain). If this adapter is used with a class that does not contain stack map
 * table attributes (i.e., pre Java 6 classes) then this adapter may not be able to compute the
 * stack map frame for each instruction. In this case no exception is thrown but the {@link #locals}
 * and {@link #stack} fields will be null for these instructions.
 *
 * @author Eric Bruneton
 */
public class AnalyzerAdapter extends MethodVisitor {

  
The local variable slots for the current execution frame. Primitive types are represented by Opcodes.TOP, Opcodes.INTEGER, Opcodes.FLOAT, Opcodes.LONG, Opcodes.DOUBLE,Opcodes.NULL or Opcodes.UNINITIALIZED_THIS (long and double are represented by two elements, the second one being TOP). Reference types are represented by String objects (representing internal names), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value). This field is null for unreachable instructions. /**
   * The local variable slots for the current execution frame. Primitive types are represented by
   * {@link Opcodes#TOP}, {@link Opcodes#INTEGER}, {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
   * {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or {@link Opcodes#UNINITIALIZED_THIS} (long and
   * double are represented by two elements, the second one being TOP). Reference types are
   * represented by String objects (representing internal names), and uninitialized types by Label
   * objects (this label designates the NEW instruction that created this uninitialized value). This
   * field is {@literal null} for unreachable instructions.
   */
  public List<Object> locals;

  
The operand stack slots for the current execution frame. Primitive types are represented by Opcodes.TOP, Opcodes.INTEGER, Opcodes.FLOAT, Opcodes.LONG, Opcodes.DOUBLE,Opcodes.NULL or Opcodes.UNINITIALIZED_THIS (long and double are represented by two elements, the second one being TOP). Reference types are represented by String objects (representing internal names), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value). This field is null for unreachable instructions. /**
   * The operand stack slots for the current execution frame. Primitive types are represented by
   * {@link Opcodes#TOP}, {@link Opcodes#INTEGER}, {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
   * {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or {@link Opcodes#UNINITIALIZED_THIS} (long and
   * double are represented by two elements, the second one being TOP). Reference types are
   * represented by String objects (representing internal names), and uninitialized types by Label
   * objects (this label designates the NEW instruction that created this uninitialized value). This
   * field is {@literal null} for unreachable instructions.
   */
  public List<Object> stack;

  
The labels that designate the next instruction to be visited. May be null. /** The labels that designate the next instruction to be visited. May be {@literal null}. */
  private List<Label> labels;

  
The uninitialized types in the current execution frame. This map associates internal names to
Label objects. Each label designates a NEW instruction that created the currently uninitialized
types, and the associated internal name represents the NEW operand, i.e. the final, initialized
type value.
/**
   * The uninitialized types in the current execution frame. This map associates internal names to
   * Label objects. Each label designates a NEW instruction that created the currently uninitialized
   * types, and the associated internal name represents the NEW operand, i.e. the final, initialized
   * type value.
   */
  public Map<Object, Object> uninitializedTypes;

  
The maximum stack size of this method. /** The maximum stack size of this method. */
  private int maxStack;

  
The maximum number of local variables of this method. /** The maximum number of local variables of this method. */
  private int maxLocals;

  
The owner's class name. /** The owner's class name. */
  private String owner;

  
Constructs a new AnalyzerAdapter. Subclasses must not use this constructor. Instead, they must use the AnalyzerAdapter(int, String, int, String, String, MethodVisitor) version. 
Params:
owner – the owner's class name.
access – the method's access flags (see Opcodes).
name – the method's name.
descriptor – the method's descriptor (see Type).
methodVisitor – the method visitor to which this adapter delegates calls. May be 
    null.
Throws:
IllegalStateException – If a subclass calls this constructor./**
   * Constructs a new {@link AnalyzerAdapter}. <i>Subclasses must not use this constructor</i>.
   * Instead, they must use the {@link #AnalyzerAdapter(int, String, int, String, String,
   * MethodVisitor)} version.
   *
   * @param owner the owner's class name.
   * @param access the method's access flags (see {@link Opcodes}).
   * @param name the method's name.
   * @param descriptor the method's descriptor (see {@link Type}).
   * @param methodVisitor the method visitor to which this adapter delegates calls. May be {@literal
   *     null}.
   * @throws IllegalStateException If a subclass calls this constructor.
   */
  public AnalyzerAdapter(
      final String owner,
      final int access,
      final String name,
      final String descriptor,
      final MethodVisitor methodVisitor) {
    this(Opcodes.ASM7, owner, access, name, descriptor, methodVisitor);
    if (getClass() != AnalyzerAdapter.class) {
      throw new IllegalStateException();
    }
  }

  
Constructs a new AnalyzerAdapter. 
Params:
api – the ASM API version implemented by this visitor. Must be one of Opcodes.ASM4, Opcodes.ASM5, Opcodes.ASM6 or Opcodes.ASM7.
owner – the owner's class name.
access – the method's access flags (see Opcodes).
name – the method's name.
descriptor – the method's descriptor (see Type).
methodVisitor – the method visitor to which this adapter delegates calls. May be 
    null./**
   * Constructs a new {@link AnalyzerAdapter}.
   *
   * @param api the ASM API version implemented by this visitor. Must be one of {@link
   *     Opcodes#ASM4}, {@link Opcodes#ASM5}, {@link Opcodes#ASM6} or {@link Opcodes#ASM7}.
   * @param owner the owner's class name.
   * @param access the method's access flags (see {@link Opcodes}).
   * @param name the method's name.
   * @param descriptor the method's descriptor (see {@link Type}).
   * @param methodVisitor the method visitor to which this adapter delegates calls. May be {@literal
   *     null}.
   */
  protected AnalyzerAdapter(
      final int api,
      final String owner,
      final int access,
      final String name,
      final String descriptor,
      final MethodVisitor methodVisitor) {
    super(api, methodVisitor);
    this.owner = owner;
    locals = new ArrayList<>();
    stack = new ArrayList<>();
    uninitializedTypes = new HashMap<>();

    if ((access & Opcodes.ACC_STATIC) == 0) {
      if ("<init>".equals(name)) {
        locals.add(Opcodes.UNINITIALIZED_THIS);
      } else {
        locals.add(owner);
      }
    }
    for (Type argumentType : Type.getArgumentTypes(descriptor)) {
      switch (argumentType.getSort()) {
        case Type.BOOLEAN:
        case Type.CHAR:
        case Type.BYTE:
        case Type.SHORT:
        case Type.INT:
          locals.add(Opcodes.INTEGER);
          break;
        case Type.FLOAT:
          locals.add(Opcodes.FLOAT);
          break;
        case Type.LONG:
          locals.add(Opcodes.LONG);
          locals.add(Opcodes.TOP);
          break;
        case Type.DOUBLE:
          locals.add(Opcodes.DOUBLE);
          locals.add(Opcodes.TOP);
          break;
        case Type.ARRAY:
          locals.add(argumentType.getDescriptor());
          break;
        case Type.OBJECT:
          locals.add(argumentType.getInternalName());
          break;
        default:
          throw new AssertionError();
      }
    }
    maxLocals = locals.size();
  }

  @Override
  public void visitFrame(
      final int type,
      final int numLocal,
      final Object[] local,
      final int numStack,
      final Object[] stack) {
    if (type != Opcodes.F_NEW) { // Uncompressed frame.
      throw new IllegalArgumentException(
          "AnalyzerAdapter only accepts expanded frames (see ClassReader.EXPAND_FRAMES)");
    }

    super.visitFrame(type, numLocal, local, numStack, stack);

    if (this.locals != null) {
      this.locals.clear();
      this.stack.clear();
    } else {
      this.locals = new ArrayList<>();
      this.stack = new ArrayList<>();
    }
    visitFrameTypes(numLocal, local, this.locals);
    visitFrameTypes(numStack, stack, this.stack);
    maxLocals = Math.max(maxLocals, this.locals.size());
    maxStack = Math.max(maxStack, this.stack.size());
  }

  private static void visitFrameTypes(
      final int numTypes, final Object[] frameTypes, final List<Object> result) {
    for (int i = 0; i < numTypes; ++i) {
      Object frameType = frameTypes[i];
      result.add(frameType);
      if (frameType == Opcodes.LONG || frameType == Opcodes.DOUBLE) {
        result.add(Opcodes.TOP);
      }
    }
  }

  @Override
  public void visitInsn(final int opcode) {
    super.visitInsn(opcode);
    execute(opcode, 0, null);
    if ((opcode >= Opcodes.IRETURN && opcode <= Opcodes.RETURN) || opcode == Opcodes.ATHROW) {
      this.locals = null;
      this.stack = null;
    }
  }

  @Override
  public void visitIntInsn(final int opcode, final int operand) {
    super.visitIntInsn(opcode, operand);
    execute(opcode, operand, null);
  }

  @Override
  public void visitVarInsn(final int opcode, final int var) {
    super.visitVarInsn(opcode, var);
    boolean isLongOrDouble =
        opcode == Opcodes.LLOAD
            || opcode == Opcodes.DLOAD
            || opcode == Opcodes.LSTORE
            || opcode == Opcodes.DSTORE;
    maxLocals = Math.max(maxLocals, var + (isLongOrDouble ? 2 : 1));
    execute(opcode, var, null);
  }

  @Override
  public void visitTypeInsn(final int opcode, final String type) {
    if (opcode == Opcodes.NEW) {
      if (labels == null) {
        Label label = new Label();
        labels = new ArrayList<>(3);
        labels.add(label);
        if (mv != null) {
          mv.visitLabel(label);
        }
      }
      for (Label label : labels) {
        uninitializedTypes.put(label, type);
      }
    }
    super.visitTypeInsn(opcode, type);
    execute(opcode, 0, type);
  }

  @Override
  public void visitFieldInsn(
      final int opcode, final String owner, final String name, final String descriptor) {
    super.visitFieldInsn(opcode, owner, name, descriptor);
    execute(opcode, 0, descriptor);
  }

  @Override
  public void visitMethodInsn(
      final int opcodeAndSource,
      final String owner,
      final String name,
      final String descriptor,
      final boolean isInterface) {
    if (api < Opcodes.ASM5 && (opcodeAndSource & Opcodes.SOURCE_DEPRECATED) == 0) {
      // Redirect the call to the deprecated version of this method.
      super.visitMethodInsn(opcodeAndSource, owner, name, descriptor, isInterface);
      return;
    }
    super.visitMethodInsn(opcodeAndSource, owner, name, descriptor, isInterface);
    int opcode = opcodeAndSource & ~Opcodes.SOURCE_MASK;

    if (this.locals == null) {
      labels = null;
      return;
    }
    pop(descriptor);
    if (opcode != Opcodes.INVOKESTATIC) {
      Object value = pop();
      if (opcode == Opcodes.INVOKESPECIAL && name.equals("<init>")) {
        Object initializedValue;
        if (value == Opcodes.UNINITIALIZED_THIS) {
          initializedValue = this.owner;
        } else {
          initializedValue = uninitializedTypes.get(value);
        }
        for (int i = 0; i < locals.size(); ++i) {
          if (locals.get(i) == value) {
            locals.set(i, initializedValue);
          }
        }
        for (int i = 0; i < stack.size(); ++i) {
          if (stack.get(i) == value) {
            stack.set(i, initializedValue);
          }
        }
      }
    }
    pushDescriptor(descriptor);
    labels = null;
  }

  @Override
  public void visitInvokeDynamicInsn(
      final String name,
      final String descriptor,
      final Handle bootstrapMethodHandle,
      final Object... bootstrapMethodArguments) {
    super.visitInvokeDynamicInsn(name, descriptor, bootstrapMethodHandle, bootstrapMethodArguments);
    if (this.locals == null) {
      labels = null;
      return;
    }
    pop(descriptor);
    pushDescriptor(descriptor);
    labels = null;
  }

  @Override
  public void visitJumpInsn(final int opcode, final Label label) {
    super.visitJumpInsn(opcode, label);
    execute(opcode, 0, null);
    if (opcode == Opcodes.GOTO) {
      this.locals = null;
      this.stack = null;
    }
  }

  @Override
  public void visitLabel(final Label label) {
    super.visitLabel(label);
    if (labels == null) {
      labels = new ArrayList<>(3);
    }
    labels.add(label);
  }

  @Override
  public void visitLdcInsn(final Object value) {
    super.visitLdcInsn(value);
    if (this.locals == null) {
      labels = null;
      return;
    }
    if (value instanceof Integer) {
      push(Opcodes.INTEGER);
    } else if (value instanceof Long) {
      push(Opcodes.LONG);
      push(Opcodes.TOP);
    } else if (value instanceof Float) {
      push(Opcodes.FLOAT);
    } else if (value instanceof Double) {
      push(Opcodes.DOUBLE);
      push(Opcodes.TOP);
    } else if (value instanceof String) {
      push("java/lang/String");
    } else if (value instanceof Type) {
      int sort = ((Type) value).getSort();
      if (sort == Type.OBJECT || sort == Type.ARRAY) {
        push("java/lang/Class");
      } else if (sort == Type.METHOD) {
        push("java/lang/invoke/MethodType");
      } else {
        throw new IllegalArgumentException();
      }
    } else if (value instanceof Handle) {
      push("java/lang/invoke/MethodHandle");
    } else if (value instanceof ConstantDynamic) {
      pushDescriptor(((ConstantDynamic) value).getDescriptor());
    } else {
      throw new IllegalArgumentException();
    }
    labels = null;
  }

  @Override
  public void visitIincInsn(final int var, final int increment) {
    super.visitIincInsn(var, increment);
    maxLocals = Math.max(maxLocals, var + 1);
    execute(Opcodes.IINC, var, null);
  }

  @Override
  public void visitTableSwitchInsn(
      final int min, final int max, final Label dflt, final Label... labels) {
    super.visitTableSwitchInsn(min, max, dflt, labels);
    execute(Opcodes.TABLESWITCH, 0, null);
    this.locals = null;
    this.stack = null;
  }

  @Override
  public void visitLookupSwitchInsn(final Label dflt, final int[] keys, final Label[] labels) {
    super.visitLookupSwitchInsn(dflt, keys, labels);
    execute(Opcodes.LOOKUPSWITCH, 0, null);
    this.locals = null;
    this.stack = null;
  }

  @Override
  public void visitMultiANewArrayInsn(final String descriptor, final int numDimensions) {
    super.visitMultiANewArrayInsn(descriptor, numDimensions);
    execute(Opcodes.MULTIANEWARRAY, numDimensions, descriptor);
  }

  @Override
  public void visitLocalVariable(
      final String name,
      final String descriptor,
      final String signature,
      final Label start,
      final Label end,
      final int index) {
    char firstDescriptorChar = descriptor.charAt(0);
    maxLocals =
        Math.max(
            maxLocals, index + (firstDescriptorChar == 'J' || firstDescriptorChar == 'D' ? 2 : 1));
    super.visitLocalVariable(name, descriptor, signature, start, end, index);
  }

  @Override
  public void visitMaxs(final int maxStack, final int maxLocals) {
    if (mv != null) {
      this.maxStack = Math.max(this.maxStack, maxStack);
      this.maxLocals = Math.max(this.maxLocals, maxLocals);
      mv.visitMaxs(this.maxStack, this.maxLocals);
    }
  }

  // -----------------------------------------------------------------------------------------------

  private Object get(final int local) {
    maxLocals = Math.max(maxLocals, local + 1);
    return local < locals.size() ? locals.get(local) : Opcodes.TOP;
  }

  private void set(final int local, final Object type) {
    maxLocals = Math.max(maxLocals, local + 1);
    while (local >= locals.size()) {
      locals.add(Opcodes.TOP);
    }
    locals.set(local, type);
  }

  private void push(final Object type) {
    stack.add(type);
    maxStack = Math.max(maxStack, stack.size());
  }

  private void pushDescriptor(final String fieldOrMethodDescriptor) {
    String descriptor =
        fieldOrMethodDescriptor.charAt(0) == '('
            ? Type.getReturnType(fieldOrMethodDescriptor).getDescriptor()
            : fieldOrMethodDescriptor;
    switch (descriptor.charAt(0)) {
      case 'V':
        return;
      case 'Z':
      case 'C':
      case 'B':
      case 'S':
      case 'I':
        push(Opcodes.INTEGER);
        return;
      case 'F':
        push(Opcodes.FLOAT);
        return;
      case 'J':
        push(Opcodes.LONG);
        push(Opcodes.TOP);
        return;
      case 'D':
        push(Opcodes.DOUBLE);
        push(Opcodes.TOP);
        return;
      case '[':
        push(descriptor);
        break;
      case 'L':
        push(descriptor.substring(1, descriptor.length() - 1));
        break;
      default:
        throw new AssertionError();
    }
  }

  private Object pop() {
    return stack.remove(stack.size() - 1);
  }

  private void pop(final int numSlots) {
    int size = stack.size();
    int end = size - numSlots;
    for (int i = size - 1; i >= end; --i) {
      stack.remove(i);
    }
  }

  private void pop(final String descriptor) {
    char firstDescriptorChar = descriptor.charAt(0);
    if (firstDescriptorChar == '(') {
      int numSlots = 0;
      Type[] types = Type.getArgumentTypes(descriptor);
      for (Type type : types) {
        numSlots += type.getSize();
      }
      pop(numSlots);
    } else if (firstDescriptorChar == 'J' || firstDescriptorChar == 'D') {
      pop(2);
    } else {
      pop(1);
    }
  }

  private void execute(final int opcode, final int intArg, final String stringArg) {
    if (opcode == Opcodes.JSR || opcode == Opcodes.RET) {
      throw new IllegalArgumentException("JSR/RET are not supported");
    }
    if (this.locals == null) {
      labels = null;
      return;
    }
    Object value1;
    Object value2;
    Object value3;
    Object t4;
    switch (opcode) {
      case Opcodes.NOP:
      case Opcodes.INEG:
      case Opcodes.LNEG:
      case Opcodes.FNEG:
      case Opcodes.DNEG:
      case Opcodes.I2B:
      case Opcodes.I2C:
      case Opcodes.I2S:
      case Opcodes.GOTO:
      case Opcodes.RETURN:
        break;
      case Opcodes.ACONST_NULL:
        push(Opcodes.NULL);
        break;
      case Opcodes.ICONST_M1:
      case Opcodes.ICONST_0:
      case Opcodes.ICONST_1:
      case Opcodes.ICONST_2:
      case Opcodes.ICONST_3:
      case Opcodes.ICONST_4:
      case Opcodes.ICONST_5:
      case Opcodes.BIPUSH:
      case Opcodes.SIPUSH:
        push(Opcodes.INTEGER);
        break;
      case Opcodes.LCONST_0:
      case Opcodes.LCONST_1:
        push(Opcodes.LONG);
        push(Opcodes.TOP);
        break;
      case Opcodes.FCONST_0:
      case Opcodes.FCONST_1:
      case Opcodes.FCONST_2:
        push(Opcodes.FLOAT);
        break;
      case Opcodes.DCONST_0:
      case Opcodes.DCONST_1:
        push(Opcodes.DOUBLE);
        push(Opcodes.TOP);
        break;
      case Opcodes.ILOAD:
      case Opcodes.FLOAD:
      case Opcodes.ALOAD:
        push(get(intArg));
        break;
      case Opcodes.LLOAD:
      case Opcodes.DLOAD:
        push(get(intArg));
        push(Opcodes.TOP);
        break;
      case Opcodes.LALOAD:
      case Opcodes.D2L:
        pop(2);
        push(Opcodes.LONG);
        push(Opcodes.TOP);
        break;
      case Opcodes.DALOAD:
      case Opcodes.L2D:
        pop(2);
        push(Opcodes.DOUBLE);
        push(Opcodes.TOP);
        break;
      case Opcodes.AALOAD:
        pop(1);
        value1 = pop();
        if (value1 instanceof String) {
          pushDescriptor(((String) value1).substring(1));
        } else if (value1 == Opcodes.NULL) {
          push(value1);
        } else {
          push("java/lang/Object");
        }
        break;
      case Opcodes.ISTORE:
      case Opcodes.FSTORE:
      case Opcodes.ASTORE:
        value1 = pop();
        set(intArg, value1);
        if (intArg > 0) {
          value2 = get(intArg - 1);
          if (value2 == Opcodes.LONG || value2 == Opcodes.DOUBLE) {
            set(intArg - 1, Opcodes.TOP);
          }
        }
        break;
      case Opcodes.LSTORE:
      case Opcodes.DSTORE:
        pop(1);
        value1 = pop();
        set(intArg, value1);
        set(intArg + 1, Opcodes.TOP);
        if (intArg > 0) {
          value2 = get(intArg - 1);
          if (value2 == Opcodes.LONG || value2 == Opcodes.DOUBLE) {
            set(intArg - 1, Opcodes.TOP);
          }
        }
        break;
      case Opcodes.IASTORE:
      case Opcodes.BASTORE:
      case Opcodes.CASTORE:
      case Opcodes.SASTORE:
      case Opcodes.FASTORE:
      case Opcodes.AASTORE:
        pop(3);
        break;
      case Opcodes.LASTORE:
      case Opcodes.DASTORE:
        pop(4);
        break;
      case Opcodes.POP:
      case Opcodes.IFEQ:
      case Opcodes.IFNE:
      case Opcodes.IFLT:
      case Opcodes.IFGE:
      case Opcodes.IFGT:
      case Opcodes.IFLE:
      case Opcodes.IRETURN:
      case Opcodes.FRETURN:
      case Opcodes.ARETURN:
      case Opcodes.TABLESWITCH:
      case Opcodes.LOOKUPSWITCH:
      case Opcodes.ATHROW:
      case Opcodes.MONITORENTER:
      case Opcodes.MONITOREXIT:
      case Opcodes.IFNULL:
      case Opcodes.IFNONNULL:
        pop(1);
        break;
      case Opcodes.POP2:
      case Opcodes.IF_ICMPEQ:
      case Opcodes.IF_ICMPNE:
      case Opcodes.IF_ICMPLT:
      case Opcodes.IF_ICMPGE:
      case Opcodes.IF_ICMPGT:
      case Opcodes.IF_ICMPLE:
      case Opcodes.IF_ACMPEQ:
      case Opcodes.IF_ACMPNE:
      case Opcodes.LRETURN:
      case Opcodes.DRETURN:
        pop(2);
        break;
      case Opcodes.DUP:
        value1 = pop();
        push(value1);
        push(value1);
        break;
      case Opcodes.DUP_X1:
        value1 = pop();
        value2 = pop();
        push(value1);
        push(value2);
        push(value1);
        break;
      case Opcodes.DUP_X2:
        value1 = pop();
        value2 = pop();
        value3 = pop();
        push(value1);
        push(value3);
        push(value2);
        push(value1);
        break;
      case Opcodes.DUP2:
        value1 = pop();
        value2 = pop();
        push(value2);
        push(value1);
        push(value2);
        push(value1);
        break;
      case Opcodes.DUP2_X1:
        value1 = pop();
        value2 = pop();
        value3 = pop();
        push(value2);
        push(value1);
        push(value3);
        push(value2);
        push(value1);
        break;
      case Opcodes.DUP2_X2:
        value1 = pop();
        value2 = pop();
        value3 = pop();
        t4 = pop();
        push(value2);
        push(value1);
        push(t4);
        push(value3);
        push(value2);
        push(value1);
        break;
      case Opcodes.SWAP:
        value1 = pop();
        value2 = pop();
        push(value1);
        push(value2);
        break;
      case Opcodes.IALOAD:
      case Opcodes.BALOAD:
      case Opcodes.CALOAD:
      case Opcodes.SALOAD:
      case Opcodes.IADD:
      case Opcodes.ISUB:
      case Opcodes.IMUL:
      case Opcodes.IDIV:
      case Opcodes.IREM:
      case Opcodes.IAND:
      case Opcodes.IOR:
      case Opcodes.IXOR:
      case Opcodes.ISHL:
      case Opcodes.ISHR:
      case Opcodes.IUSHR:
      case Opcodes.L2I:
      case Opcodes.D2I:
      case Opcodes.FCMPL:
      case Opcodes.FCMPG:
        pop(2);
        push(Opcodes.INTEGER);
        break;
      case Opcodes.LADD:
      case Opcodes.LSUB:
      case Opcodes.LMUL:
      case Opcodes.LDIV:
      case Opcodes.LREM:
      case Opcodes.LAND:
      case Opcodes.LOR:
      case Opcodes.LXOR:
        pop(4);
        push(Opcodes.LONG);
        push(Opcodes.TOP);
        break;
      case Opcodes.FALOAD:
      case Opcodes.FADD:
      case Opcodes.FSUB:
      case Opcodes.FMUL:
      case Opcodes.FDIV:
      case Opcodes.FREM:
      case Opcodes.L2F:
      case Opcodes.D2F:
        pop(2);
        push(Opcodes.FLOAT);
        break;
      case Opcodes.DADD:
      case Opcodes.DSUB:
      case Opcodes.DMUL:
      case Opcodes.DDIV:
      case Opcodes.DREM:
        pop(4);
        push(Opcodes.DOUBLE);
        push(Opcodes.TOP);
        break;
      case Opcodes.LSHL:
      case Opcodes.LSHR:
      case Opcodes.LUSHR:
        pop(3);
        push(Opcodes.LONG);
        push(Opcodes.TOP);
        break;
      case Opcodes.IINC:
        set(intArg, Opcodes.INTEGER);
        break;
      case Opcodes.I2L:
      case Opcodes.F2L:
        pop(1);
        push(Opcodes.LONG);
        push(Opcodes.TOP);
        break;
      case Opcodes.I2F:
        pop(1);
        push(Opcodes.FLOAT);
        break;
      case Opcodes.I2D:
      case Opcodes.F2D:
        pop(1);
        push(Opcodes.DOUBLE);
        push(Opcodes.TOP);
        break;
      case Opcodes.F2I:
      case Opcodes.ARRAYLENGTH:
      case Opcodes.INSTANCEOF:
        pop(1);
        push(Opcodes.INTEGER);
        break;
      case Opcodes.LCMP:
      case Opcodes.DCMPL:
      case Opcodes.DCMPG:
        pop(4);
        push(Opcodes.INTEGER);
        break;
      case Opcodes.GETSTATIC:
        pushDescriptor(stringArg);
        break;
      case Opcodes.PUTSTATIC:
        pop(stringArg);
        break;
      case Opcodes.GETFIELD:
        pop(1);
        pushDescriptor(stringArg);
        break;
      case Opcodes.PUTFIELD:
        pop(stringArg);
        pop();
        break;
      case Opcodes.NEW:
        push(labels.get(0));
        break;
      case Opcodes.NEWARRAY:
        pop();
        switch (intArg) {
          case Opcodes.T_BOOLEAN:
            pushDescriptor("[Z");
            break;
          case Opcodes.T_CHAR:
            pushDescriptor("[C");
            break;
          case Opcodes.T_BYTE:
            pushDescriptor("[B");
            break;
          case Opcodes.T_SHORT:
            pushDescriptor("[S");
            break;
          case Opcodes.T_INT:
            pushDescriptor("[I");
            break;
          case Opcodes.T_FLOAT:
            pushDescriptor("[F");
            break;
          case Opcodes.T_DOUBLE:
            pushDescriptor("[D");
            break;
          case Opcodes.T_LONG:
            pushDescriptor("[J");
            break;
          default:
            throw new IllegalArgumentException("Invalid array type " + intArg);
        }
        break;
      case Opcodes.ANEWARRAY:
        pop();
        pushDescriptor("[" + Type.getObjectType(stringArg));
        break;
      case Opcodes.CHECKCAST:
        pop();
        pushDescriptor(Type.getObjectType(stringArg).getDescriptor());
        break;
      case Opcodes.MULTIANEWARRAY:
        pop(intArg);
        pushDescriptor(stringArg);
        break;
      default:
        throw new IllegalArgumentException("Invalid opcode " + opcode);
    }
    labels = null;
  }
}