java.lang.Object
- com.ibm.wala.ssa.SSACFG

All Implemented Interfaces:

ControlFlowGraph<SSAInstruction,ISSABasicBlock>, EdgeManager<ISSABasicBlock>, Graph<ISSABasicBlock>, NodeManager<ISSABasicBlock>, NumberedEdgeManager<ISSABasicBlock>, NumberedGraph<ISSABasicBlock>, NumberedNodeManager<ISSABasicBlock>, Iterable<ISSABasicBlock>
```
public class SSACFG
extends Object
implements ControlFlowGraph<SSAInstruction,ISSABasicBlock>
```
A control-flow graph for ssa form. This implementation is uglified in the name of performance. This implementation does not directly track the graph structure, but instead delegates to a prebuilt ControlFlowGraph which stores the structure. This decision from 2004 may have been premature optimization, left over from a world where IRs and related structures were long-lived. In today's system, they are cached and reconstituted by SSACache. Perhaps we should just extend AbstractCFG and not worry so much about space. As the current implementation stands, the delegate graph stores the graph structure, and this class additionally stores SSACFG.BasicBlocks and the SSAInstruction array.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

class SSACFG.BasicBlock
A Basic Block in an SSA IR

class SSACFG.ExceptionHandlerBasicBlock

Field Summary

Fields
Modifier and Type	Field	Description
`protected AbstractCFG<IInstruction,IBasicBlock<IInstruction>>`	`delegate`	A delegate CFG, pre-built, which stores the graph structure of this CFG.
`protected SSAInstruction[]`	`instructions`	The "normal" instructions which constitute the SSA form.
`protected IMethod`	`method`	The `IMethod` this `ControlFlowGraph` represents

Constructor Summary

Constructors
Constructor Description

SSACFG(IMethod method, AbstractCFG cfg, SSAInstruction[] instructions)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`addEdge(ISSABasicBlock src, ISSABasicBlock dst)`
`void`	`addNode(ISSABasicBlock n)`	add a node to this graph
`boolean`	`containsNode(ISSABasicBlock N)`
`SSACFG.BasicBlock`	`entry()`	Return the entry basic block in the CFG
`boolean`	`equals(Object o)`
`SSACFG.BasicBlock`	`exit()`
`SSACFG.BasicBlock`	`getBasicBlock(int bb)`
`SSACFG.BasicBlock`	`getBlockForInstruction(int instructionIndex)`	Get the basic block an instruction belongs to.
`BitVector`	`getCatchBlocks()`
`Collection<ISSABasicBlock>`	`getExceptionalPredecessors(ISSABasicBlock b)`	The order of blocks returned should be arbitrary but deterministic.
`List<ISSABasicBlock>`	`getExceptionalSuccessors(ISSABasicBlock b)`	The order of blocks returned must indicate the exception-handling scope.
`SSAInstruction[]`	`getInstructions()`	NB: Use iterators such as IR.iterateAllInstructions() instead of this method.
`int`	`getMaxNumber()`
`IMethod`	`getMethod()`
`SSACFG.BasicBlock`	`getNode(int number)`
`Collection<ISSABasicBlock>`	`getNormalPredecessors(ISSABasicBlock b)`	The order of blocks returned should be arbitrary but deterministic.
`Collection<ISSABasicBlock>`	`getNormalSuccessors(ISSABasicBlock b)`	The order of blocks returned should be arbitrary but deterministic.
`int`	`getNumber(ISSABasicBlock b)`
`int`	`getNumberOfNodes()`
`int`	`getPredNodeCount(ISSABasicBlock b)`	Return the number of `immediate predecessor` nodes of n
`IntSet`	`getPredNodeNumbers(ISSABasicBlock node)`
`Iterator<ISSABasicBlock>`	`getPredNodes(ISSABasicBlock b)`	Return an `Iterator` over the immediate predecessor nodes of n This method never returns `null`.
`int`	`getProgramCounter(int index)`	TODO: move this into IR?
`int`	`getSuccNodeCount(ISSABasicBlock b)`	Return the number of `immediate successor` nodes of this Node in the Graph
`IntSet`	`getSuccNodeNumbers(ISSABasicBlock b)`
`Iterator<ISSABasicBlock>`	`getSuccNodes(ISSABasicBlock b)`	Return an Iterator over the immediate successor nodes of n
`boolean`	`hasEdge(ISSABasicBlock src, ISSABasicBlock dst)`
`boolean`	`hasExceptionalEdge(SSACFG.BasicBlock src, SSACFG.BasicBlock dest)`	has exceptional edge src -> dest
`int`	`hashCode()`
`boolean`	`hasNormalEdge(SSACFG.BasicBlock src, SSACFG.BasicBlock dest)`	has normal edge src -> dest
`boolean`	`isCatchBlock(int i)`	is the given i a catch block?
`Iterator<ISSABasicBlock>`	`iterateNodes(IntSet s)`
`Iterator<ISSABasicBlock>`	`iterator()`
`void`	`removeAllIncidentEdges(ISSABasicBlock node)`
`void`	`removeEdge(ISSABasicBlock src, ISSABasicBlock dst)`
`void`	`removeIncomingEdges(ISSABasicBlock node)`
`void`	`removeNode(ISSABasicBlock n)`	remove a node from this graph
`void`	`removeNodeAndEdges(ISSABasicBlock N)`	remove a node and all its incident edges
`void`	`removeOutgoingEdges(ISSABasicBlock node)`
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Field Detail
  - instructions
```
protected final SSAInstruction[] instructions
```
    The "normal" instructions which constitute the SSA form. This does not include SSAPhiInstructions, which dwell in SSACFG.BasicBlocks instead.
  - method
```
protected final IMethod method
```
    The IMethod this ControlFlowGraph represents
  - delegate
```
protected final AbstractCFG<IInstruction,IBasicBlock<IInstruction>> delegate
```
    A delegate CFG, pre-built, which stores the graph structure of this CFG.
- Constructor Detail
  - SSACFG
```
public SSACFG(IMethod method,
              AbstractCFG cfg,
              SSAInstruction[] instructions)
```
    Throws:
    
    IllegalArgumentException - if method is null
- Method Detail
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - getBlockForInstruction
```
public SSACFG.BasicBlock getBlockForInstruction(int instructionIndex)
```
    Get the basic block an instruction belongs to. Note: the instruction2Block array is filled in lazily. During initialization, the mapping is set up only for the first instruction of each basic block.
    
    Specified by:
    
    getBlockForInstruction in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Parameters:
    
    instructionIndex - an instruction index
    
    Returns:
    
    the basic block which contains this instruction.
  - getInstructions
```
public SSAInstruction[] getInstructions()
```
    NB: Use iterators such as IR.iterateAllInstructions() instead of this method. This will probably be deprecated someday. Return the instructions. Note that the CFG is created from the Shrike CFG prior to creating the SSA instructions.
    
    Specified by:
    
    getInstructions in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    an array containing the SSA instructions.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getCatchBlocks
```
public BitVector getCatchBlocks()
```
    Specified by:
    
    getCatchBlocks in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the indices of the catch blocks, as a bit vector
  - isCatchBlock
```
public boolean isCatchBlock(int i)
```
    is the given i a catch block?
    
    Returns:
    
    true if catch block, false otherwise
  - entry
```
public SSACFG.BasicBlock entry()
```
    Description copied from interface: ControlFlowGraph
    
    Return the entry basic block in the CFG
    
    Specified by:
    
    entry in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
  - exit
```
public SSACFG.BasicBlock exit()
```
    Specified by:
    
    exit in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the synthetic exit block for the cfg
  - getNumber
```
public int getNumber(ISSABasicBlock b)
              throws IllegalArgumentException
```
    Specified by:
    
    getNumber in interface NumberedNodeManager<ISSABasicBlock>
    
    Throws:
    
    IllegalArgumentException
  - getNode
```
public SSACFG.BasicBlock getNode(int number)
```
    Specified by:
    
    getNode in interface NumberedNodeManager<ISSABasicBlock>
  - getMaxNumber
```
public int getMaxNumber()
```
    Specified by:
    
    getMaxNumber in interface NumberedNodeManager<ISSABasicBlock>
  - iterator
```
public Iterator<ISSABasicBlock> iterator()
```
    Specified by:
    
    iterator in interface Iterable<ISSABasicBlock>
    
    Specified by:
    
    iterator in interface NodeManager<ISSABasicBlock>
    
    Returns:
    
    an Iterator of the nodes in this graph
  - getNumberOfNodes
```
public int getNumberOfNodes()
```
    Specified by:
    
    getNumberOfNodes in interface NodeManager<ISSABasicBlock>
    
    Returns:
    
    the number of nodes in this graph
  - getPredNodes
```
public Iterator<ISSABasicBlock> getPredNodes(ISSABasicBlock b)
                                      throws IllegalArgumentException
```
    Description copied from interface: EdgeManager
    
    Return an Iterator over the immediate predecessor nodes of n This method never returns null.
    
    Specified by:
    
    getPredNodes in interface EdgeManager<ISSABasicBlock>
    
    Returns:
    
    an Iterator over the immediate predecessor nodes of this Node.
    
    Throws:
    
    IllegalArgumentException
  - getPredNodeCount
```
public int getPredNodeCount(ISSABasicBlock b)
                     throws IllegalArgumentException
```
    Description copied from interface: EdgeManager
    
    Return the number of immediate predecessor nodes of n
    
    Specified by:
    
    getPredNodeCount in interface EdgeManager<ISSABasicBlock>
    
    Returns:
    
    the number of immediate predecessors of n.
    
    Throws:
    
    IllegalArgumentException
  - getSuccNodes
```
public Iterator<ISSABasicBlock> getSuccNodes(ISSABasicBlock b)
                                      throws IllegalArgumentException
```
    Description copied from interface: EdgeManager
    
    Return an Iterator over the immediate successor nodes of n
    This method never returns null.
    
    Specified by:
    
    getSuccNodes in interface EdgeManager<ISSABasicBlock>
    
    Returns:
    
    an Iterator over the immediate successor nodes of n
    
    Throws:
    
    IllegalArgumentException
  - getSuccNodeCount
```
public int getSuccNodeCount(ISSABasicBlock b)
                     throws IllegalArgumentException
```
    Description copied from interface: EdgeManager
    
    Return the number of immediate successor nodes of this Node in the Graph
    
    Specified by:
    
    getSuccNodeCount in interface EdgeManager<ISSABasicBlock>
    
    Returns:
    
    the number of immediate successor Nodes of this Node in the Graph.
    
    Throws:
    
    IllegalArgumentException
  - addNode
```
public void addNode(ISSABasicBlock n)
             throws UnsupportedOperationException
```
    Description copied from interface: NodeManager
    
    add a node to this graph
    
    Specified by:
    
    addNode in interface NodeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - addEdge
```
public void addEdge(ISSABasicBlock src,
                    ISSABasicBlock dst)
             throws UnsupportedOperationException
```
    Specified by:
    
    addEdge in interface EdgeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - removeEdge
```
public void removeEdge(ISSABasicBlock src,
                       ISSABasicBlock dst)
                throws UnsupportedOperationException
```
    Specified by:
    
    removeEdge in interface EdgeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - removeAllIncidentEdges
```
public void removeAllIncidentEdges(ISSABasicBlock node)
                            throws UnsupportedOperationException
```
    Specified by:
    
    removeAllIncidentEdges in interface EdgeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - removeNodeAndEdges
```
public void removeNodeAndEdges(ISSABasicBlock N)
                        throws UnsupportedOperationException
```
    Description copied from interface: Graph
    
    remove a node and all its incident edges
    
    Specified by:
    
    removeNodeAndEdges in interface Graph<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException - if the graph implementation does not allow removal
  - removeNode
```
public void removeNode(ISSABasicBlock n)
                throws UnsupportedOperationException
```
    Description copied from interface: NodeManager
    
    remove a node from this graph
    
    Specified by:
    
    removeNode in interface NodeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - getProgramCounter
```
public int getProgramCounter(int index)
```
    Description copied from interface: ControlFlowGraph
    
    TODO: move this into IR?
    
    Specified by:
    
    getProgramCounter in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Parameters:
    
    index - an instruction index
    
    Returns:
    
    the program counter (bytecode index) corresponding to that instruction
  - containsNode
```
public boolean containsNode(ISSABasicBlock N)
```
    Specified by:
    
    containsNode in interface NodeManager<ISSABasicBlock>
    
    Returns:
    
    true iff the graph contains the specified node
  - getMethod
```
public IMethod getMethod()
```
    Specified by:
    
    getMethod in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the Method this CFG represents
  - getExceptionalSuccessors
```
public List<ISSABasicBlock> getExceptionalSuccessors(ISSABasicBlock b)
```
    Description copied from interface: ControlFlowGraph
    
    The order of blocks returned must indicate the exception-handling scope. So the first block is the first candidate catch block, and so on. With this invariant one can compute the exceptional control flow for a given exception type.
    
    Specified by:
    
    getExceptionalSuccessors in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the basic blocks which may be reached from b via exceptional control flow
  - getExceptionalPredecessors
```
public Collection<ISSABasicBlock> getExceptionalPredecessors(ISSABasicBlock b)
```
    Description copied from interface: ControlFlowGraph
    
    The order of blocks returned should be arbitrary but deterministic.
    
    Specified by:
    
    getExceptionalPredecessors in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the basic blocks from which b may be reached via exceptional control flow
  - hasExceptionalEdge
```
public boolean hasExceptionalEdge(SSACFG.BasicBlock src,
                                  SSACFG.BasicBlock dest)
```
    has exceptional edge src -> dest
    
    Throws:
    
    IllegalArgumentException - if dest is null
  - hasNormalEdge
```
public boolean hasNormalEdge(SSACFG.BasicBlock src,
                             SSACFG.BasicBlock dest)
```
    has normal edge src -> dest
    
    Throws:
    
    IllegalArgumentException - if dest is null
  - getNormalSuccessors
```
public Collection<ISSABasicBlock> getNormalSuccessors(ISSABasicBlock b)
```
    Description copied from interface: ControlFlowGraph
    
    The order of blocks returned should be arbitrary but deterministic.
    
    Specified by:
    
    getNormalSuccessors in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the basic blocks which may be reached from b via normal control flow
  - getNormalPredecessors
```
public Collection<ISSABasicBlock> getNormalPredecessors(ISSABasicBlock b)
```
    Description copied from interface: ControlFlowGraph
    
    The order of blocks returned should be arbitrary but deterministic.
    
    Specified by:
    
    getNormalPredecessors in interface ControlFlowGraph<SSAInstruction,ISSABasicBlock>
    
    Returns:
    
    the basic blocks from which b may be reached via normal control flow
  - iterateNodes
```
public Iterator<ISSABasicBlock> iterateNodes(IntSet s)
```
    Specified by:
    
    iterateNodes in interface NumberedNodeManager<ISSABasicBlock>
    
    Returns:
    
    iterator of nodes with the numbers in set s
  - removeIncomingEdges
```
public void removeIncomingEdges(ISSABasicBlock node)
                         throws UnsupportedOperationException
```
    Specified by:
    
    removeIncomingEdges in interface EdgeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - removeOutgoingEdges
```
public void removeOutgoingEdges(ISSABasicBlock node)
                         throws UnsupportedOperationException
```
    Specified by:
    
    removeOutgoingEdges in interface EdgeManager<ISSABasicBlock>
    
    Throws:
    
    UnsupportedOperationException
  - hasEdge
```
public boolean hasEdge(ISSABasicBlock src,
                       ISSABasicBlock dst)
                throws UnimplementedError
```
    Specified by:
    
    hasEdge in interface EdgeManager<ISSABasicBlock>
    
    Throws:
    
    UnimplementedError
  - getSuccNodeNumbers
```
public IntSet getSuccNodeNumbers(ISSABasicBlock b)
                          throws IllegalArgumentException
```
    Specified by:
    
    getSuccNodeNumbers in interface NumberedEdgeManager<ISSABasicBlock>
    
    Returns:
    
    the numbers identifying the immediate successors of node
    
    Throws:
    
    IllegalArgumentException
  - getPredNodeNumbers
```
public IntSet getPredNodeNumbers(ISSABasicBlock node)
                          throws UnimplementedError
```
    Specified by:
    
    getPredNodeNumbers in interface NumberedEdgeManager<ISSABasicBlock>
    
    Returns:
    
    the numbers identifying the immediate predecessors of node
    
    Throws:
    
    UnimplementedError
  - getBasicBlock
```
public SSACFG.BasicBlock getBasicBlock(int bb)
```
    Returns:
    
    the basic block with a particular number

Modifier and Type	Class	Description
`class`	`SSACFG.BasicBlock`	A Basic Block in an SSA IR
`class`	`SSACFG.ExceptionHandlerBasicBlock`

Class SSACFG

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Field Detail

instructions

method

delegate

Constructor Detail

SSACFG

Method Detail

hashCode

equals

getBlockForInstruction

getInstructions

toString

getCatchBlocks

isCatchBlock

entry

exit

getNumber

getNode

getMaxNumber

iterator

getNumberOfNodes

getPredNodes

getPredNodeCount

getSuccNodes

getSuccNodeCount

addNode

addEdge

removeEdge

removeAllIncidentEdges

removeNodeAndEdges

removeNode

getProgramCounter

containsNode

getMethod

getExceptionalSuccessors

getExceptionalPredecessors

hasExceptionalEdge

hasNormalEdge

getNormalSuccessors

getNormalPredecessors

iterateNodes

removeIncomingEdges

removeOutgoingEdges

hasEdge

getSuccNodeNumbers

getPredNodeNumbers

getBasicBlock