org.checkerframework.dataflow.constantpropagation

Class ConstantPropagationStore

java.lang.Object

org.checkerframework.dataflow.constantpropagation.ConstantPropagationStore

All Implemented Interfaces:

Store<ConstantPropagationStore>

public class ConstantPropagationStore
extends Object
implements Store<ConstantPropagationStore>

A store that records information about constant values.

Nested Class Summary

Nested classes/interfaces inherited from interface org.checkerframework.dataflow.analysis.Store

Store.FlowRule, Store.Kind

Constructor Summary

Constructors

Modifier	Constructor and Description
	ConstantPropagationStore() Creates a new ConstantPropagationStore.
protected	ConstantPropagationStore(Map<Node,Constant> contents)

Method Summary

Modifier and Type	Method and Description
boolean	canAlias(JavaExpression a, JavaExpression b) Can the objects a and b be aliases? Returns a conservative answer (i.e., returns true if not enough information is available to determine aliasing).
ConstantPropagationStore	copy() Returns an exact copy of this store.
boolean	equals(@Nullable Object o) Returns true if this is equal to the given argument.
Constant	getInformation(Node n)
int	hashCode()
ConstantPropagationStore	leastUpperBound(ConstantPropagationStore other) Compute the least upper bound of two stores.
void	mergeInformation(Node n, Constant val)
void	setInformation(Node n, Constant val)
String	toString()
String	visualize(CFGVisualizer<?,ConstantPropagationStore,?> viz) Delegate visualization responsibility to a visualizer.
ConstantPropagationStore	widenedUpperBound(ConstantPropagationStore previous) Compute an upper bound of two stores that is wider than the least upper bound of the two stores.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantPropagationStore

public ConstantPropagationStore()

Creates a new ConstantPropagationStore.

ConstantPropagationStore

protected ConstantPropagationStore(Map<Node,Constant> contents)

Method Detail

getInformation

public Constant getInformation(Node n)

mergeInformation

public void mergeInformation(Node n,
                             Constant val)

setInformation

public void setInformation(Node n,
                           Constant val)

copy

public ConstantPropagationStore copy()

Description copied from interface: Store

Returns an exact copy of this store.

Specified by:

copy in interface Store<ConstantPropagationStore>

Returns:

an exact copy of this store

leastUpperBound

public ConstantPropagationStore leastUpperBound(ConstantPropagationStore other)

Description copied from interface: Store

Compute the least upper bound of two stores.

Important: This method must fulfill the following contract:

• Does not change this.
• Does not change other.
• Returns a fresh object which is not aliased yet.
• Returns an object of the same (dynamic) type as this, even if the signature is more permissive.
• Is commutative.

Specified by:

leastUpperBound in interface Store<ConstantPropagationStore>

widenedUpperBound

public ConstantPropagationStore widenedUpperBound(ConstantPropagationStore previous)

Description copied from interface: Store

Compute an upper bound of two stores that is wider than the least upper bound of the two stores. Used to jump to a higher abstraction to allow faster termination of the fixed point computations in Analysis. previous must be the previous store.

A particular analysis might not require widening and should implement this method by calling leastUpperBound.

Important: This method must fulfill the following contract:

• Does not change this.
• Does not change previous.
• Returns a fresh object which is not aliased yet.
• Returns an object of the same (dynamic) type as this, even if the signature is more permissive.
• Is commutative.

Specified by:

widenedUpperBound in interface Store<ConstantPropagationStore>

Parameters:

previous - must be the previous store

equals

public boolean equals(@Nullable Object o)

Description copied from interface: Store

Returns true if this is equal to the given argument.

Specified by:

equals in interface Store<ConstantPropagationStore>

Overrides:

equals in class Object

Parameters:

o - the object to compare against this

Returns:

true if this is equal to the given argument

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

canAlias

public boolean canAlias(JavaExpression a,
                        JavaExpression b)

Description copied from interface: Store

Can the objects a and b be aliases? Returns a conservative answer (i.e., returns true if not enough information is available to determine aliasing).

Specified by:

canAlias in interface Store<ConstantPropagationStore>

visualize

public String visualize(CFGVisualizer<?,ConstantPropagationStore,?> viz)

Delegate visualization responsibility to a visualizer.

value is null because ConstantPropagationStore doesn't support visualization.

Specified by:

visualize in interface Store<ConstantPropagationStore>

Parameters:

viz - the visualizer to visualize this store

Returns:

the String representation of this store