soot.toolkits.graph
Class UnitGraph

java.lang.Object
  soot.toolkits.graph.UnitGraph

All Implemented Interfaces:

Iterable<Unit>, DirectedGraph<Unit>

Direct Known Subclasses:

BriefUnitGraph, EnhancedUnitGraph, ExceptionalUnitGraph, TrapUnitGraph

public abstract class UnitGraph
extends Object
implements DirectedGraph<Unit>

Represents a CFG where the nodes are Unit instances and edges represent unexceptional and (possibly) exceptional control flow between Units.

This is an abstract class, providing the facilities used to build CFGs for specific purposes.

Field Summary

protected Body	body
protected List<Unit>	heads
protected SootMethod	method
protected List<Unit>	tails
protected Chain<Unit>	unitChain
protected Map<Unit,List<Unit>>	unitToPreds
protected Map<Unit,List<Unit>>	unitToSuccs

Constructor Summary

protected

UnitGraph(Body body) Performs the work that is required to construct any sort of UnitGraph.

Method Summary

protected void	addEdge(Map<Unit,List<Unit>> unitToSuccs, Map<Unit,List<Unit>> unitToPreds, Unit head, Unit tail) Utility method for adding an edge to maps representing the CFG.
protected void	buildHeadsAndTails() Utility method used in the construction of UnitGraphs, to be called only after the unitToPreds and unitToSuccs maps have been built.
protected void	buildUnexceptionalEdges(Map<Unit,List<Unit>> unitToSuccs, Map<Unit,List<Unit>> unitToPreds) Utility method for UnitGraph constructors.
protected Map<Unit,List<Unit>>	combineMapValues(Map<Unit,List<Unit>> mapA, Map<Unit,List<Unit>> mapB) Utility method that produces a new map from the Units of this graph's body to the union of the values stored in the two argument Maps, used to combine the maps of exceptional and unexceptional predecessors and successors into maps of all predecessors and successors.
Body	getBody()
List<Unit>	getExtendedBasicBlockPathBetween(Unit from, Unit to) Look for a path in graph, from def to use.
List<Unit>	getHeads() Returns a list of entry points for this graph.
List<Unit>	getPredsOf(Unit u) Returns a list of predecessors for the given node in the graph.
List<Unit>	getSuccsOf(Unit u) Returns a list of successors for the given node in the graph.
List<Unit>	getTails() Returns a list of exit points for this graph.
Iterator<Unit>	iterator() Returns an iterator for the nodes in this graph.
protected static void	makeMappedListsUnmodifiable(Map<?,List<Unit>> map) Utility method that replaces the values of a Map, which must be instances of List, with unmodifiable equivalents.
int	size() Returns the node count for this graph.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

heads

protected List<Unit> heads

tails

protected List<Unit> tails

unitToSuccs

protected Map<Unit,List<Unit>> unitToSuccs

unitToPreds

protected Map<Unit,List<Unit>> unitToPreds

method

protected SootMethod method

body

protected Body body

unitChain

protected Chain<Unit> unitChain

Constructor Detail

UnitGraph

protected UnitGraph(Body body)

Performs the work that is required to construct any sort of UnitGraph.

Parameters:

body - The body of the method for which to construct a control flow graph.

Method Detail

buildUnexceptionalEdges

protected void buildUnexceptionalEdges(Map<Unit,List<Unit>> unitToSuccs,
                                       Map<Unit,List<Unit>> unitToPreds)

Utility method for UnitGraph constructors. It computes the edges corresponding to unexceptional control flow.

Parameters:

unitToSuccs - A Map from Units to Lists of Units. This is an ``out parameter''; callers must pass an empty Map. buildUnexceptionalEdges will add a mapping for every Unit in the body to a list of its unexceptional successors.

unitToPreds - A Map from Units to Lists of Units. This is an ``out parameter''; callers must pass an empty Map. buildUnexceptionalEdges will add a mapping for every Unit in the body to a list of its unexceptional predecessors.

buildHeadsAndTails

protected void buildHeadsAndTails()

Utility method used in the construction of UnitGraphs, to be called only after the unitToPreds and unitToSuccs maps have been built.

UnitGraph provides an implementation of buildHeadsAndTails() which defines the graph's set of heads to include the first Unit in the graph's body, together with any other Unit which has no predecessors. It defines the graph's set of tails to include all Units with no successors. Subclasses of UnitGraph may override this method to change the criteria for classifying a node as a head or tail.

makeMappedListsUnmodifiable

protected static void makeMappedListsUnmodifiable(Map<?,List<Unit>> map)

Utility method that replaces the values of a Map, which must be instances of List, with unmodifiable equivalents.

Parameters:

map - The map whose values are to be made unmodifiable.

combineMapValues

protected Map<Unit,List<Unit>> combineMapValues(Map<Unit,List<Unit>> mapA,
                                                Map<Unit,List<Unit>> mapB)

Utility method that produces a new map from the Units of this graph's body to the union of the values stored in the two argument Maps, used to combine the maps of exceptional and unexceptional predecessors and successors into maps of all predecessors and successors. The values stored in both argument maps must be Lists of Units, which are assumed not to contain any duplicate Units.

Parameters:

mapA - The first map to be combined.

mapB - The second map to be combined.

addEdge

protected void addEdge(Map<Unit,List<Unit>> unitToSuccs,
                       Map<Unit,List<Unit>> unitToPreds,
                       Unit head,
                       Unit tail)

Utility method for adding an edge to maps representing the CFG.

Parameters:

unitToSuccs - The Map from Units to Lists of their successors.

unitToPreds - The Map from Units to Lists of their successors.

head - The Unit from which the edge starts.

tail - The Unit to which the edge flows.

getBody

public Body getBody()

Returns:

The body from which this UnitGraph was built.

See Also:

Body

getExtendedBasicBlockPathBetween

public List<Unit> getExtendedBasicBlockPathBetween(Unit from,
                                                   Unit to)

Look for a path in graph, from def to use. This path has to lie inside an extended basic block (and this property implies uniqueness.). The path returned includes from and to.

Parameters:

from - start point for the path.

to - end point for the path.

Returns:

null if there is no such path.

getHeads

public List<Unit> getHeads()

Description copied from interface: DirectedGraph

Returns a list of entry points for this graph.

Specified by:

getHeads in interface DirectedGraph<Unit>

getTails

public List<Unit> getTails()

Description copied from interface: DirectedGraph

Returns a list of exit points for this graph.

Specified by:

getTails in interface DirectedGraph<Unit>

getPredsOf

public List<Unit> getPredsOf(Unit u)

Description copied from interface: DirectedGraph

Returns a list of predecessors for the given node in the graph.

Specified by:

getPredsOf in interface DirectedGraph<Unit>

getSuccsOf

public List<Unit> getSuccsOf(Unit u)

Description copied from interface: DirectedGraph

Returns a list of successors for the given node in the graph.

Specified by:

getSuccsOf in interface DirectedGraph<Unit>

size

public int size()

Description copied from interface: DirectedGraph

Returns the node count for this graph.

Specified by:

size in interface DirectedGraph<Unit>

iterator

public Iterator<Unit> iterator()

Description copied from interface: DirectedGraph

Returns an iterator for the nodes in this graph. No specific ordering of the nodes is guaranteed.

Specified by:

iterator in interface Iterable<Unit>

Specified by:

iterator in interface DirectedGraph<Unit>

toString

public String toString()

Overrides:

toString in class Object