Package ghidra.program.model.pcode

Class Varnode

java.lang.Object
ghidra.program.model.pcode.Varnode
Direct Known Subclasses:
VarnodeAST, VarnodeOperation
public class Varnode extends Object
Rawest possible Varnode. Just a variable location and size, not part of a syntax tree. A raw varnode is said to be free, it is not attached to any variable.

  • Constructor Details

    • Varnode

      public Varnode(Address a, int sz)
      Parameters:
      a - location varnode attached to
      sz - size of varnode

    • Varnode

      public Varnode(Address a, int sz, int symbolKey)
      Parameters:
      a - location varnode attached to
      sz - size of varnode
      symbolKey - associated symbol key

  • Method Details

    • getSize

      public int getSize()
      Returns:
      size of the varnode in bytes

    • getSpace

      public int getSpace()
      Returns:
      the space this varnode belongs to (ram, register, ...)

    • getAddress

      public Address getAddress()
      Returns:
      the address this varnode is attached to

    • getPCAddress

      public Address getPCAddress()
      Get the address where this varnode is defined or NO_ADDRESS if this varnode is an input
      Returns:
      the address

    • getOffset

      public long getOffset()
      Returns:
      the offset into the address space varnode is defined within

    • getWordOffset

      public long getWordOffset()
      Returns the word offset into the address space this is defined within The word size is defined in the Language's .slaspec file with the "WORDSIZE" argument when DEFINEing a memory SPACE (capitalization is for emphasis; the directives are actually lowercase).
      Returns:
      the word offset into the address space this is defined within

    • isFree

      public boolean isFree()

    • contains

      public boolean contains(Address addr)
      Determine if this varnode contains the specified address
      Parameters:
      addr - the address for which to check
      Returns:
      true if this varnode contains the specified address

    • intersects

      public boolean intersects(Varnode varnode)
      Determine if this varnode intersects another varnode.
      Parameters:
      varnode - other varnode
      Returns:
      true if this varnode intersects the specified varnode

    • intersects

      public boolean intersects(AddressSetView set)
      Determine if this varnode intersects the specified address set
      Parameters:
      set - address set
      Returns:
      true if this varnode intersects the specified address set

    • isAddress

      public boolean isAddress()
      Returns:
      true if this varnode exists in a Memory space (vs. register etc...). Keep in mind this varnode may also correspond to a defined register if true is returned and isRegister() return false. Memory-based registers may be indirectly addressed which leads to the distinction with registers within the register space.

    • isRegister

      public boolean isRegister()
      Returns:
      true if this varnode exists in a Register type space. If false is returned, keep in mind this varnode may still correspond to a defined register within a memory space. Memory-based registers may be indirectly addressed which leads to the distinction with registers within the register space.

    • isConstant

      public boolean isConstant()
      Returns:
      true if this varnode is just a constant number

    • isUnique

      public boolean isUnique()
      Returns:
      true if this varnode doesn't exist anywhere. A temporary variable.

    • isHash

      public boolean isHash()

    • isInput

      public boolean isInput()
      Returns:
      is input to a pcode op

    • isPersistent

      public boolean isPersistent()
      Returns:
      is persistent

    • isAddrTied

      public boolean isAddrTied()
      Returns:
      is mapped to an address

    • isUnaffected

      public boolean isUnaffected()

    • getDef

      public PcodeOp getDef()
      Returns:
      get the pcode op this varnode belongs to

    • getDescendants

      public Iterator<PcodeOp> getDescendants()
      Returns:
      iterator to all PcodeOp s that take this as input

    • getLoneDescend

      public PcodeOp getLoneDescend()
      If there is only one PcodeOp taking this varnode as input, return it. Otherwise return null
      Returns:
      the lone descendant PcodeOp

    • hasNoDescend

      public boolean hasNoDescend()
      Returns:
      false if the Varnode has a PcodeOp reading it that is part of function data-flow

    • getHigh

      public HighVariable getHigh()
      Returns:
      the high level variable this varnode represents

    • getMergeGroup

      public short getMergeGroup()
      Returns:
      the index of the group, within the high containing this, that are forced merged with this

    • encodeRaw

      public void encodeRaw(Encoder encoder) throws IOException
      Encode just the raw storage info for this Varnode to stream
      Parameters:
      encoder - is the stream encoder
      Throws:
      IOException - for errors in the underlying stream

    • encodePiece

      public String encodePiece()
      Encode details of the Varnode as a formatted string with three colon separated fields. space:offset:size The name of the address space, the offset of the address as a hex number, and the size field as a decimal number.
      Returns:
      the formatted String

    • decode

      public static Varnode decode(Decoder decoder, PcodeFactory factory) throws DecoderException
      Decode a Varnode from a stream
      Parameters:
      decoder - is the stream decoder
      factory - pcode factory used to create valid pcode
      Returns:
      the new Varnode
      Throws:
      DecoderException - if the Varnode is improperly encoded

    • decodePieces

      public static Varnode.Join decodePieces(Decoder decoder) throws DecoderException
      Decode a sequence of Varnodes from "piece" attributes for the current open element. The Varnodes are normally associated with an Address in the "join" space. In this virtual space, a contiguous sequence of bytes, at a specific Address, represent a logical value that may physically be split across multiple registers or other storage locations.
      Parameters:
      decoder - is the stream decoder
      Returns:
      an array of decoded Varnodes and the logical size
      Throws:
      DecoderException - for any errors in the encoding

    • trim

      public void trim()
      Trim a varnode in a constant space to the correct starting offset. Constant handles may contain constants of indeterminate size. This is where the size gets fixed, i.e. we mask off the constant to its proper size. A varnode that is ends up in pcode should call this method to ensure that varnodes always contains raw data. On the other hand, varnodes in handles are allowed to have offsets that violate size restrictions.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • toString

      public String toString(Language language)
      Convert this varnode to an alternate String representation based on a specified language.
      Parameters:
      language - is the specified Language
      Returns:
      string representation

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object