Package javassist.bytecode

Class StackMap

java.lang.Object
javassist.bytecode.AttributeInfo
javassist.bytecode.StackMap
public class StackMap extends AttributeInfo
Another stack_map attribute defined in CLDC 1.1 for J2ME.

This is an entry in the attributes table of a Code attribute. It was introduced by J2ME CLDC 1.1 (JSR 139) for pre-verification.

According to the CLDC specification, the sizes of some fields are not 16bit but 32bit if the code size is more than 64K or the number of the local variables is more than 64K. However, for the J2ME CLDC technology, they are always 16bit. The implementation of the StackMap class assumes they are 16bit.

Since:
3.12
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    StackMap.Walker
    A code walker for a StackMap attribute.
    static class 
    StackMap.Writer
    Internal use only.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    DOUBLE
    Double_variable_info.tag.
    static final int
    FLOAT
    Float_variable_info.tag.
    static final int
    INTEGER
    Integer_variable_info.tag.
    static final int
    LONG
    Long_variable_info.tag.
    static final int
    NULL
    Null_variable_info.tag.
    static final int
    OBJECT
    Object_variable_info.tag.
    static final String
    tag
    The name of this attribute "StackMap".
    static final int
    THIS
    UninitializedThis_variable_info.tag.
    static final int
    TOP
    Top_variable_info.tag.
    static final int
    UNINIT
    Uninitialized_variable_info.tag.

  • Method Summary

    Modifier and Type
    Method
    Description
    AttributeInfo
    copy(ConstPool newCp, Map<String,String> classnames)
    Makes a copy.
    void
    insertLocal(int index, int tag, int classInfo)
    Updates this stack map table when a new local variable is inserted for a new parameter.
    int
    numOfEntries()
    Returns number_of_entries.
    void
    print(PrintWriter out)
    Prints this stack map.
    void
    removeNew(int where)
    Undocumented method.

    Methods inherited from class javassist.bytecode.AttributeInfo

    get, getConstPool, getName, length, set

    Methods inherited from class java.lang.Object

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

  • Field Details

  • Method Details

    • numOfEntries

      public int numOfEntries()
      Returns number_of_entries.

    • copy

      public AttributeInfo copy(ConstPool newCp, Map<String,String> classnames)
      Makes a copy.
      Overrides:
      copy in class AttributeInfo
      Parameters:
      newCp - the constant pool table used by the new copy.
      classnames - pairs of replaced and substituted class names.

    • insertLocal

      public void insertLocal(int index, int tag, int classInfo) throws BadBytecode
      Updates this stack map table when a new local variable is inserted for a new parameter.
      Parameters:
      index - the index of the added local variable.
      tag - the type tag of that local variable. It is available by StackMapTable.typeTagOf(char).
      classInfo - the index of the CONSTANT_Class_info structure in a constant pool table. This should be zero unless the tag is ITEM_Object.
      Throws:
      BadBytecode
      See Also:

    • removeNew

      public void removeNew(int where) throws CannotCompileException
      Undocumented method. Do not use; internal-use only.

      This method is for javassist.convert.TransformNew. It is called to update the stack map when the NEW opcode (and the following DUP) is removed.

      Parameters:
      where - the position of the removed NEW opcode.
      Throws:
      CannotCompileException

    • print

      public void print(PrintWriter out)
      Prints this stack map.