Package edu.umd.cs.findbugs.ba.vna

Class ValueNumber

java.lang.Object

edu.umd.cs.findbugs.ba.vna.ValueNumber

All Implemented Interfaces:

java.lang.Comparable<ValueNumber>

public class ValueNumber
extends java.lang.Object
implements java.lang.Comparable<ValueNumber>

A "value number" is a value produced somewhere in a methods. We use value numbers as dataflow values in Frames. When two frame slots have the same value number, then the same value is in both of those slots.

Instances of ValueNumbers produced by the same ValueNumberFactory are unique, so reference equality may be used to determine whether or not two value numbers are the same. In general, ValueNumbers from different factories cannot be compared.

See Also:

ValueNumberAnalysis

Field Summary

Fields

Modifier and Type	Field	Description
static int	ARRAY_VALUE
(package private) static MapCache<ValueNumber,ValueNumber>	cache
static int	CONSTANT_CLASS_OBJECT
static int	CONSTANT_VALUE
(package private) int	flags	Flags representing meta information about the value.
(package private) int	number	The value number.
static int	PHI_NODE
static int	RETURN_VALUE	Flag specifying that this value was the return value of a called method.
(package private) static int	valueNumbersCreated
(package private) static int	valueNumbersReused

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ValueNumber(int number, int flags)

Method Summary

Modifier and Type	Method	Description
int	compareTo(ValueNumber other)
static ValueNumber	createValueNumber(int number)
static ValueNumber	createValueNumber(int number, int flags)
boolean	equals(java.lang.Object o)
int	getFlags()
int	getNumber()
boolean	hasFlag(int flag)
int	hashCode()
static int	mergeFlags(int flags1, int flags2)
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

cache

static MapCache<ValueNumber,ValueNumber> cache

valueNumbersCreated

static int valueNumbersCreated

valueNumbersReused

static int valueNumbersReused

number

final int number

The value number.

flags

final int flags

Flags representing meta information about the value. When value numbers are merged, their flags should be the flags common to both.

RETURN_VALUE

public static final int RETURN_VALUE

Flag specifying that this value was the return value of a called method.

See Also:

Constant Field Values

ARRAY_VALUE

public static final int ARRAY_VALUE

See Also:

Constant Field Values

CONSTANT_CLASS_OBJECT

public static final int CONSTANT_CLASS_OBJECT

See Also:

Constant Field Values

PHI_NODE

public static final int PHI_NODE

See Also:

Constant Field Values

CONSTANT_VALUE

public static final int CONSTANT_VALUE

See Also:

Constant Field Values

Constructor Detail

ValueNumber

private ValueNumber(int number,
                    int flags)

Method Detail

mergeFlags

public static int mergeFlags(int flags1,
                             int flags2)

createValueNumber

public static ValueNumber createValueNumber(int number,
                                            int flags)

createValueNumber

public static ValueNumber createValueNumber(int number)

getNumber

public int getNumber()

getFlags

public int getFlags()

hasFlag

public boolean hasFlag(int flag)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

compareTo

public int compareTo(ValueNumber other)

Specified by:

compareTo in interface java.lang.Comparable<ValueNumber>