Package serp.bytecode

Class ConstantInstruction

All Implemented Interfaces:
BCEntity, VisitAcceptor

public class ConstantInstruction extends TypedInstruction
An instruction that that loads a constant onto the stack. The opcode represented by this instruction may change depending on the type and value of the constant set. For example, if the constant value is initially set to 5, the opcode will be iconst5; if later incremented to 6, the opcode will be changed to bipush(6).
  • Field Details

    • _arg

      private int _arg
  • Constructor Details

    • ConstantInstruction

      ConstantInstruction(Code owner)
    • ConstantInstruction

      ConstantInstruction(Code owner, int opcode)
  • Method Details

    • getLength

      int getLength()
      Description copied from class: Instruction
      Return the length in bytes of this opcode, including all arguments. For many opcodes this method relies on an up-to-date byte index.
      Overrides:
      getLength in class Instruction
    • getStackChange

      public int getStackChange()
      Description copied from class: Instruction
      Return the number of stack positions this instruction pushes or pops during its execution.
      Overrides:
      getStackChange in class Instruction
      Returns:
      0 if the stack is not affected by this instruction, a positive number if it pushes onto the stack, and a negative number if it pops from the stack
    • getLogicalStackChange

      public int getLogicalStackChange()
      Description copied from class: Instruction
      Return the logical number of stack positions changed by this instruction. In other words, ignore weirdness with longs and doubles taking two stack positions.
      Overrides:
      getLogicalStackChange in class Instruction
    • getTypeName

      public String getTypeName()
      Description copied from class: TypedInstruction
      Return the type name for this instruction. If the type has not been set, this method will return null.
      Specified by:
      getTypeName in class TypedInstruction
    • setType

      public TypedInstruction setType(String type)
      Description copied from class: TypedInstruction
      Set the type of this instruction. Types that have no direct support will be converted accordingly.
      Specified by:
      setType in class TypedInstruction
      Returns:
      this instruction, for method chaining
    • getValue

      public Object getValue()
      Return the value of the constant as its wrapper type, or null if not set. Returns class values as the class name.
    • setValue

      public ConstantInstruction setValue(Object value)
      Set the constant to the given value. The value should be an instance of String, Integer, Long, Double, Float, Class, BCClass, or null depending on the constant type. If the given value is not supported directly, it will be converted accordingly.
      Returns:
      this instruction, for method chaining
    • getStringValue

      public String getStringValue()
      Return the string value of this constant, or null if not set.
    • getIntValue

      public int getIntValue()
      Return the int value of this constant, or 0 if not set.
    • getLongValue

      public long getLongValue()
      Return the long value of this constant, or 0 if not set.
    • getFloatValue

      public float getFloatValue()
      Return the float value of this constant, or 0 if not set.
    • getDoubleValue

      public double getDoubleValue()
      Return the double value of this constant, or 0 if not set.
    • getClassNameValue

      public String getClassNameValue()
      Return the class value of this constant, or null if not set.
    • setNull

      public ConstantInstruction setNull()
      Set this constant to null.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(String value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(String value, boolean clsName)
    • setValue

      public ConstantInstruction setValue(Class value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(BCClass value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(int value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(long value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(float value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(double value)
      Set the value of this constant.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(boolean value)
      Set the value of this constant; note that this type is converted to int.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(short value)
      Set the value of this constant; note that this type is converted to int.
      Returns:
      this instruction, for method chaining
    • setValue

      public ConstantInstruction setValue(char value)
      Set the value of this constant; note that this type is converted to int.
      Returns:
      this instruction, for method chaining
    • equalsInstruction

      public boolean equalsInstruction(Instruction other)
      ConstantInstructions are equal if the const they reference is the same, or if the const of either is unset.
      Overrides:
      equalsInstruction in class Instruction
    • acceptVisit

      public void acceptVisit(BCVisitor visit)
      Description copied from interface: VisitAcceptor
      Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this one.
      Specified by:
      acceptVisit in interface VisitAcceptor
      Overrides:
      acceptVisit in class Instruction
    • read

      void read(Instruction orig)
      Description copied from class: Instruction
      Copy the given instruction data.
      Overrides:
      read in class Instruction
    • read

      void read(DataInput in) throws IOException
      Description copied from class: Instruction
      Read the arguments for this opcode from the given stream. This method should be overridden by opcodes that take arguments.
      Overrides:
      read in class Instruction
      Throws:
      IOException
    • write

      void write(DataOutput out) throws IOException
      Description copied from class: Instruction
      Write the arguments for this opcode to the given stream. This method should be overridden by opcodes that take arguments.
      Overrides:
      write in class Instruction
      Throws:
      IOException
    • calculateOpcode

      private void calculateOpcode(Object value, boolean clsName, boolean wide)
    • ensureBytecodeVersion

      private void ensureBytecodeVersion()
      When adding class entries, make sure the bytecode spec supports them.