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InstructionFactory.java

package de.fub.bytecode.generic;

import de.fub.bytecode.Constants;

/** 
 * Instances of this class may be used, e.g., to generate typed
 * versions of instructions.  Its main purpose is to be used as the
 * byte code generating backend of a compiler. You can subclass it to
 * add your own create methods.
 *
 * @version $Id: InstructionFactory.java,v 1.1.1.1 2002/01/24 03:44:05 pserver Exp $
 * @author <A HREF="http://www.inf.fu-berlin.de/~dahm">M. Dahm</A>
 */
public class InstructionFactory implements InstructionConstants {
  protected ClassGen        cg;
  protected ConstantPoolGen cp;

  /** Need a ClassGen object to obtain a constant pool, e.g.
   */
  public InstructionFactory(ClassGen cg) {
    this.cg = cg;
    cp = cg.getConstantPool();
  }  
  /**
   * @param type type of elements of array, i.e. array.getElementType()
   */
  public static ArrayInstruction createArrayLoad(Type type) {
    switch(type.getType()) {
    case Constants.T_BOOLEAN:
    case Constants.T_BYTE:   return BALOAD;
    case Constants.T_CHAR:   return CALOAD;
    case Constants.T_SHORT:  return SALOAD;
    case Constants.T_INT:    return IALOAD;
    case Constants.T_FLOAT:  return FALOAD;
    case Constants.T_DOUBLE: return DALOAD;
    case Constants.T_LONG:   return LALOAD;
    case Constants.T_ARRAY:
    case Constants.T_OBJECT: return AALOAD;
    default:       throw new RuntimeException("Invalid type " + type);
    }
  }  
  /**
   * @param type type of elements of array, i.e. array.getElementType()
   */
  public static ArrayInstruction createArrayStore(Type type) {
    switch(type.getType()) {
    case Constants.T_BOOLEAN:
    case Constants.T_BYTE:   return BASTORE;
    case Constants.T_CHAR:   return CASTORE;
    case Constants.T_SHORT:  return SASTORE;
    case Constants.T_INT:    return IASTORE;
    case Constants.T_FLOAT:  return FASTORE;
    case Constants.T_DOUBLE: return DASTORE;
    case Constants.T_LONG:   return LASTORE;
    case Constants.T_ARRAY:
    case Constants.T_OBJECT: return AASTORE;
    default:       throw new RuntimeException("Invalid type " + type);
    }
  }  
  private static final ArithmeticInstruction createBinaryDoubleOp(char op) {
    switch(op) {
    case '-' : return DSUB;
    case '+' : return DADD;
    case '*' : return DMUL;
    case '/' : return DDIV;
    default: throw new RuntimeException("Invalid operand " + op);
    }
  }  
  private static final ArithmeticInstruction createBinaryFloatOp(char op) {
    switch(op) {
    case '-' : return FSUB;
    case '+' : return FADD;
    case '*' : return FMUL;
    case '/' : return FDIV;
    default: throw new RuntimeException("Invalid operand " + op);
    }
  }  
  private static final ArithmeticInstruction createBinaryIntOp(char first, String op) {
    switch(first) {
    case '-' : return ISUB;
    case '+' : return IADD;
    case '%' : return IREM;
    case '*' : return IMUL;
    case '/' : return IDIV;
    case '&' : return IAND;
    case '|' : return IOR;
    case '^' : return IXOR;
    case '<' : return ISHL;
    case '>' : return op.equals(">>>")? (ArithmeticInstruction)IUSHR :
      (ArithmeticInstruction)ISHR;
    default: throw new RuntimeException("Invalid operand " + op);
    }
  }  
  private static final ArithmeticInstruction createBinaryLongOp(char first, String op) {
    switch(first) {
    case '-' : return LSUB;
    case '+' : return LADD;
    case '%' : return LREM;
    case '*' : return LMUL;
    case '/' : return LDIV;
    case '&' : return LAND;
    case '|' : return LOR;
    case '^' : return LXOR;
    case '<' : return LSHL;
    case '>' : return op.equals(">>>")? (ArithmeticInstruction)LUSHR :
      (ArithmeticInstruction)LSHR;
    default: throw new RuntimeException("Invalid operand " + op);
    }
  }  
  /**
   * Create binary operation for simple basic types, such as int and float.
   *
   * @param op operation, such as "+", "*", "<<", etc.
   */
  public static ArithmeticInstruction createBinaryOperation(String op, Type type) {
    char first = op.toCharArray()[0];

    switch(type.getType()) {
    case Constants.T_BYTE:
    case Constants.T_SHORT:
    case Constants.T_INT:
    case Constants.T_CHAR:    return createBinaryIntOp(first, op);
    case Constants.T_LONG:    return createBinaryLongOp(first, op);
    case Constants.T_FLOAT:   return createBinaryFloatOp(first);
    case Constants.T_DOUBLE:  return createBinaryDoubleOp(first);
    default:        throw new RuntimeException("Invalid type " + type);
    }
  }  
  /** Create conversion operation for two stack operands, this may be an I2C, instruction, e.g.,
   * if the operands are basic types and CHECKCAST if they are reference types.
   */
  public Instruction createCast(Type src_type, Type dest_type) {
    if((src_type instanceof BasicType) && (dest_type instanceof BasicType)) {
      byte dest = dest_type.getType();
      byte src  = src_type.getType();

      if(dest == Constants.T_LONG && (src == Constants.T_CHAR || src == Constants.T_BYTE ||
                      src == Constants.T_SHORT))
    src = Constants.T_INT;

      String[] short_names = { "C", "F", "D", "B", "S", "I", "L" };

      String name = "de.fub.bytecode.generic." + short_names[src - Constants.T_CHAR] +
    "2" + short_names[dest - Constants.T_CHAR];
      
      Instruction i = null;
      try {
    i = (Instruction)java.lang.Class.forName(name).newInstance();
      } catch(Exception e) {
    throw new RuntimeException("Could not find instruction: " + name);
      }

      return i;
    } else if((src_type instanceof ReferenceType) && (dest_type instanceof ReferenceType)) {
      if(dest_type instanceof ArrayType)
    return new CHECKCAST(cp.addArrayClass((ArrayType)dest_type));
      else
    return new CHECKCAST(cp.addClass(((ObjectType)dest_type).getClassName()));
    }
    else
      throw new RuntimeException("Can not cast " + src_type + " to " + dest_type);
  }  
  public CHECKCAST createCheckCast(ReferenceType t) {
    if(t instanceof ArrayType)
      return new CHECKCAST(cp.addArrayClass((ArrayType)t));
    else
      return new CHECKCAST(cp.addClass((ObjectType)t));
  }  
  /**
   * @param size size of operand, either 1 (int, e.g.) or 2 (double)
   */
  public static StackInstruction createDup(int size) {
    return (size == 2)? (StackInstruction)DUP2 :
      (StackInstruction)DUP;
  }  
  /**
   * @param size size of operand, either 1 (int, e.g.) or 2 (double)
   */
  public static StackInstruction createDup_1(int size) {
    return (size == 2)? (StackInstruction)DUP2_X1 :
      (StackInstruction)DUP_X1;
  }  
  /**
   * @param size size of operand, either 1 (int, e.g.) or 2 (double)
   */
  public static StackInstruction createDup_2(int size) {
    return (size == 2)? (StackInstruction)DUP2_X2 :
      (StackInstruction)DUP_X2;
  }  
  public GETFIELD createGetField(String class_name, String name, Type t) {
    return new GETFIELD(cp.addFieldref(class_name, name, t.getSignature()));
  }  
  public GETSTATIC createGetStatic(String class_name, String name, Type t) {
    return new GETSTATIC(cp.addFieldref(class_name, name, t.getSignature()));
  }  
  /** Create an invoke instruction.
   *
   * @param class_name name of the called class
   * @param name name of the called method
   * @param ret_type return type of method
   * @param arg_types argument types of method
   * @param kind how to invoke, i.e. INVOKEINTERFACE, INVOKESTATIC, INVOKEVIRTUAL,
   * or INVOKESPECIAL
   */
  public InvokeInstruction createInvoke(String class_name, String name, Type ret_type,
                    Type[] arg_types, short kind) {
    int    index;
    int    nargs      = 0;
    String signature  = Type.getMethodSignature(ret_type, arg_types);

    for(int i=0; i < arg_types.length; i++) // Count size of arguments
      nargs += arg_types[i].getSize();

    if(kind == Constants.INVOKEINTERFACE)
      index = cp.addInterfaceMethodref(class_name, name, signature);
    else
      index = cp.addMethodref(class_name, name, signature);

    switch(kind) {
    case Constants.INVOKESPECIAL:   return new INVOKESPECIAL(index);
    case Constants.INVOKEVIRTUAL:   return new INVOKEVIRTUAL(index);
    case Constants.INVOKESTATIC:    return new INVOKESTATIC(index);
    case Constants.INVOKEINTERFACE: return new INVOKEINTERFACE(index, nargs + 1);
    default:
      throw new RuntimeException("Oops: Unknown invoke kind:" + kind);
    }
  }  
  /**
   * @param index index of local variable
   */
  public static LocalVariableInstruction createLoad(Type type, int index) {
    switch(type.getType()) {
    case Constants.T_BOOLEAN:
    case Constants.T_CHAR:
    case Constants.T_BYTE:
    case Constants.T_SHORT:
    case Constants.T_INT:    return new ILOAD(index);
    case Constants.T_FLOAT:  return new FLOAD(index);
    case Constants.T_DOUBLE: return new DLOAD(index);
    case Constants.T_LONG:   return new LLOAD(index);
    case Constants.T_ARRAY:
    case Constants.T_OBJECT: return new ALOAD(index);
    default:       throw new RuntimeException("Invalid type " + type);
    }
  }  
  public NEW createNew(ObjectType t) {
    return new NEW(cp.addClass(t));
  }  
  public NEW createNew(String s) {
    return createNew(new ObjectType(s));
  }  
  /** Create new array of given size and type.
   */
  public AllocationInstruction createNewArray(Type t, short dim) {
    if(dim == 1) {
      if(t instanceof ObjectType)
    return new ANEWARRAY(cp.addClass((ObjectType)t));
      else if(t instanceof ArrayType)
    return new ANEWARRAY(cp.addArrayClass((ArrayType)t));
      else
    return new NEWARRAY(((BasicType)t).getType());
    } else {
      ArrayType at;

      if(t instanceof ArrayType)
    at = (ArrayType)t;
      else
    at = new ArrayType(t, dim);

      return new MULTIANEWARRAY(cp.addArrayClass(at), dim);
    }
  }  
  /*public AllocationInstruction createNewArray(ArrayType t, short dim) {
if(dim == 1)
return createNewArray(t.getElementType());
else
return new MULTIANEWARRAY(cp.addArrayClass(t), dim);
}
  public AllocationInstruction createNewArray(Type t, short dim) {
    return createNewArray(new ArrayType(t, dim));
  }
  public AllocationInstruction createNewArray(ArrayType t) {
    int dim = t.getDimensions();

    if(dim == 1) {
      Type type = t.getBasicType();

      if(type instanceof ObjectType)
    return new ANEWARRAY(cp.addClass((ObjectType)type));
      else
    return new NEWARRAY(((BasicType)type).getType());
    } else
      return new MULTIANEWARRAY(cp.addArrayClass(t), (short)dim);
      }*/
 
  /** Create "null" value for reference types, 0 for basic types like int
   */
  public static Instruction createNull(Type type) {
    switch(type.getType()) {
    case Constants.T_ARRAY:
    case Constants.T_OBJECT:  return ACONST_NULL;
    case Constants.T_INT:
    case Constants.T_SHORT:
    case Constants.T_BOOLEAN:
    case Constants.T_CHAR: 
    case Constants.T_BYTE:    return ICONST_0;
    case Constants.T_FLOAT:   return FCONST_0;
    case Constants.T_DOUBLE:  return DCONST_0;
    case Constants.T_LONG:    return LCONST_0;
    case Constants.T_VOID:    return NOP;

    default:
      throw new RuntimeException("Invalid type: " + type);
    }
  }  
  /**
   * @param size size of operand, either 1 (int, e.g.) or 2 (double)
   */
  public static StackInstruction createPop(int size) {
    return (size == 2)? (StackInstruction)POP2 :
      (StackInstruction)POP;
  }  
  public PUTFIELD createPutField(String class_name, String name, Type t) {
    return new PUTFIELD(cp.addFieldref(class_name, name, t.getSignature()));
  }  
  public PUTSTATIC createPutStatic(String class_name, String name, Type t) {
    return new PUTSTATIC(cp.addFieldref(class_name, name, t.getSignature()));
  }  
  /** Create typed return
   */
  public static ReturnInstruction createReturn(Type type) {
    switch(type.getType()) {
    case Constants.T_ARRAY:
    case Constants.T_OBJECT:  return ARETURN;
    case Constants.T_INT:
    case Constants.T_SHORT:
    case Constants.T_BOOLEAN:
    case Constants.T_CHAR: 
    case Constants.T_BYTE:    return IRETURN;
    case Constants.T_FLOAT:   return FRETURN;
    case Constants.T_DOUBLE:  return DRETURN;
    case Constants.T_LONG:    return LRETURN;
    case Constants.T_VOID:    return RETURN;

    default:
      throw new RuntimeException("Invalid type: " + type);
    }
  }  
  /**
   * @param index index of local variable
   */
  public static LocalVariableInstruction createStore(Type type, int index) {
    switch(type.getType()) {
    case Constants.T_BOOLEAN:
    case Constants.T_CHAR:
    case Constants.T_BYTE:
    case Constants.T_SHORT:
    case Constants.T_INT:    return new ISTORE(index);
    case Constants.T_FLOAT:  return new FSTORE(index);
    case Constants.T_DOUBLE: return new DSTORE(index);
    case Constants.T_LONG:   return new LSTORE(index);
    case Constants.T_ARRAY:
    case Constants.T_OBJECT: return new ASTORE(index);
    default:       throw new RuntimeException("Invalid type " + type);
    }
  }  
  /** Create reference to `this'
   */
  public static Instruction createThis() {
    return new ALOAD(0);
  }  
}

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