Package serp.bytecode

Class SwitchInstruction

All Implemented Interfaces:
BCEntity, InstructionPtr, VisitAcceptor

public abstract class SwitchInstruction extends JumpInstruction
Contains functionality common to the different switch types (TableSwitch and LookupSwitch).
Author:
Eric Lindauer
  • Constructor Details

    • SwitchInstruction

      public SwitchInstruction(Code owner, int opcode)
  • Method Details

    • getOffsets

      public int[] getOffsets()
      Returns the current byte offsets for the different switch cases in this Instruction.
    • setOffsets

      public void setOffsets(int[] offsets)
      Sets the offsets for the instructions representing the different switch statement cases. WARNING: these offsets will not be changed in the event that the code is modified following this call. It is typically a good idea to follow this call with a call to updateTargets as soon as the instructions at the given offsets are valid, at which point the Instructions themselves will be used as the targets and the offsets will be updated as expected.
    • countTargets

      public int countTargets()
    • getDefaultTarget

      public Instruction getDefaultTarget()
    • getDefaultOffset

      public int getDefaultOffset()
    • setDefaultOffset

      public SwitchInstruction setDefaultOffset(int offset)
    • setDefaultTarget

      public SwitchInstruction setDefaultTarget(Instruction ins)
    • getTargets

      public Instruction[] getTargets()
      Return the targets for this switch, or empty array if not set.
    • setTargets

      public SwitchInstruction setTargets(Instruction[] targets)
      Set the jump points for this switch.
      Returns:
      this instruction, for method chaining
    • addTarget

      public SwitchInstruction addTarget(Instruction target)
      Add a target to this switch.
      Returns:
      this instruction, for method chaining
    • 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
    • updateTargets

      public void updateTargets()
      Description copied from interface: InstructionPtr
      Use the byte indexes read from the class file to calculate and set references to the target instruction(s) for this ptr. This method will be called after the byte code has been read in for the first time and before it is written after modification.
      Specified by:
      updateTargets in interface InstructionPtr
      Overrides:
      updateTargets in class JumpInstruction
    • replaceTarget

      public void replaceTarget(Instruction oldTarget, Instruction newTarget)
      Description copied from interface: InstructionPtr
      Replace the given old, likely invalid, target with a new target. The new target Instruction is guaranteed to be in the same code block as this InstructionPtr.
      Specified by:
      replaceTarget in interface InstructionPtr
      Overrides:
      replaceTarget in class JumpInstruction
    • setCases

      public SwitchInstruction setCases(int[] matches, Instruction[] targets)
      Set the match-jumppt pairs for this switch.
      Returns:
      this instruction, for method chaining
    • setMatches

      public SwitchInstruction setMatches(int[] matches)
    • addCase

      public SwitchInstruction addCase(int match, Instruction target)
      Add a case to this switch.
      Returns:
      this instruction, for method chaining
    • addMatch

      public abstract SwitchInstruction addMatch(int match)
    • getMatches

      public abstract int[] getMatches()