Package org.jboss.byteman.agent.adapter.cfg

Class InstructionSequence

  • public class InstructionSequence
extends java.lang.Object
    Class used to hold a sequence of instructions within a basic block

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int[] encodedInstructions
      data array storing instructions and their operands encoded as ints.
      private int[] instructionOffsets
      since instructions are encoded with their operands we need an offsets array to identify where each instruction strats, allowing instructions and their operand to be searched forwards and backwards
      private int numEncoded
      the number of valid entries in array encodedInstructions
      private int numInstructions
      the number of valid offsets to instructions in array instructionOffsets

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int add​(int insn)
      add an instruction to the sequence
      int add​(int insn, int arg1)
      add an instruction with one encoded argument to the sequence
      int add​(int insn, int[] args)
      add an instruction with an arbitrary number of encoded arguments to the sequence
      int add​(int insn, int arg1, int arg2)
      add an instruction with two encoded arguments to the sequence
      int add​(int insn, int arg1, int arg2, int arg3)
      add an instruction with three encoded arguments to the sequence
      int add​(int insn, int arg1, int arg2, int arg3, int arg4)
      add an instruction with four encoded arguments to the sequence
      private void ensureSpace​(int count)
      expand the offsets array if necessary to allow room for 1 more instructions with count more arguments
      int get​(int i)
      return the instruction at the supplied offset
      int getArg​(int i, int j)
      return a specific encoded argument of a given instruction
      int getArgCount​(int i)
      return the number of encoded arguments of a given instruction
      int getType​(int i)
      return the type of a given instruction
      int size()
      return the number of instructions in the sequence

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • instructionOffsets

        private int[] instructionOffsets
        since instructions are encoded with their operands we need an offsets array to identify where each instruction strats, allowing instructions and their operand to be searched forwards and backwards

      • numInstructions

        private int numInstructions
        the number of valid offsets to instructions in array instructionOffsets

      • encodedInstructions

        private int[] encodedInstructions
        data array storing instructions and their operands encoded as ints. integer operands are embedded as is operands which are strings (type, const, field etc) must be translated via the names array in the associated cfg. operands which are jump labels must be translated by calling getNthOut() on the associated basic block.

      • numEncoded

        private int numEncoded
        the number of valid entries in array encodedInstructions

    • Constructor Detail

      • InstructionSequence

        public InstructionSequence()

    • Method Detail

      • ensureSpace

        private void ensureSpace​(int count)
        expand the offsets array if necessary to allow room for 1 more instructions with count more arguments

      • size

        public int size()
        return the number of instructions in the sequence
        Returns:
        the the number of instructions in the sequence

      • get

        public int get​(int i)
        return the instruction at the supplied offset
        Parameters:
        i - the offset
        Returns:
        the ith instruction in the sequuence

      • getType

        public int getType​(int i)
        return the type of a given instruction
        Parameters:
        i - the instruction index
        Returns:
        the ith instruction in the sequuence

      • getArgCount

        public int getArgCount​(int i)
        return the number of encoded arguments of a given instruction
        Parameters:
        i - the offset of the instruction
        Returns:
        the number of encoded arguments of the ith instruction in the sequuence

      • getArg

        public int getArg​(int i,
                  int j)
        return a specific encoded argument of a given instruction
        Parameters:
        i - the offset of the instruction
        j - the index of the arguument attached to the instruction
        Returns:
        the jth encoded argument of the ith instruction in the sequuence

      • add

        public int add​(int insn)
        add an instruction to the sequence
        Parameters:
        insn - the instruction
        Returns:
        the index of the newly added instruction

      • add

        public int add​(int insn,
               int arg1)
        add an instruction with one encoded argument to the sequence
        Parameters:
        insn - the instruction
        arg1 - the argument index
        Returns:
        the index of the newly added instruction

      • add

        public int add​(int insn,
               int arg1,
               int arg2)
        add an instruction with two encoded arguments to the sequence
        Parameters:
        insn - the instruction
        arg1 - the first argument index
        arg2 - the second argument index
        Returns:
        the index of the newly added instruction

      • add

        public int add​(int insn,
               int arg1,
               int arg2,
               int arg3)
        add an instruction with three encoded arguments to the sequence
        Parameters:
        insn - the instruction
        arg1 - the first argument index
        arg2 - the second argument index
        arg3 - the third argument index
        Returns:
        the index of the newly added instruction

      • add

        public int add​(int insn,
               int arg1,
               int arg2,
               int arg3,
               int arg4)
        add an instruction with four encoded arguments to the sequence
        Parameters:
        insn - the instruction
        arg1 - the first argument index
        arg2 - the second argument index
        arg3 - the third argument index
        arg4 - the third argument index
        Returns:
        the index of the newly added instruction

      • add

        public int add​(int insn,
               int[] args)
        add an instruction with an arbitrary number of encoded arguments to the sequence
        Parameters:
        insn - the instruction
        args - the arguments
        Returns:
        the index of the newly added instruction