sofya.graphs.cfg
Class Block

java.lang.Object
  sofya.graphs.Node
      sofya.graphs.cfg.Block

All Implemented Interfaces:

SConstants

public class Block
extends Node

A block represents a basic block of a control flow graph. A basic block is one in which control enters at one end and exits at the other end without being broken. A block knows about its label, type, subtype, offset where it starts, and offset where it ends.

Version:

09/24/2004

Author:

Alex Kinneer

Nested Class Summary

Nested classes/interfaces inherited from interface sofya.base.SConstants

SConstants.BlockLabel, SConstants.BlockObjectType, SConstants.BlockSubType, SConstants.BlockType, SConstants.BranchObjectType, SConstants.BranchType, SConstants.EDObjectType, SConstants.TraceObjectType

Field Summary

protected int	endOffset The end offset of this block.
protected java.lang.Object	endRef Reference to a relevant entity at the end of the block.
protected SConstants.BlockLabel	label The character label for the node type of this block.
protected int	startOffset The start offset of this block.
protected java.lang.Object	startRef Reference to a relevant entity at the start of the block.
protected SConstants.BlockSubType	subType The integer mapping to the subtype of this block.
protected SConstants.BlockType	type The integer mapping to the type of this block.
static Block[]	ZL_ARRAY Zero-length block array useful for specifying array cast types to methods such Node.getSuccessors(Node[]).

Fields inherited from class sofya.graphs.Node

nodeID, predecessors, successors

Fields inherited from interface sofya.base.SConstants

DEFAULT_PORT, INST_COMPATIBLE, INST_OLD_UNSUPPORTED, INST_OPT_NORMAL, INST_OPT_SEQUENCE, SIG_CHKALIVE, SIG_ECHO

Constructor Summary

Block()
Creates a new block with fields initialized to default values.

Block(int id)
Creates a new block with a given ID and all other fields initialized to default values.

Block(int id, SConstants.BlockType type, SConstants.BlockSubType subType)
Creates a new block with a given ID, type, and sub-type.

Block(int id, SConstants.BlockType type, SConstants.BlockSubType subType, SConstants.BlockLabel label)
Creates a new block.

Block(int id, SConstants.BlockType type, SConstants.BlockSubType subType, SConstants.BlockLabel label, int startOffset, int endOffset)
Creates a new block.

Block(int id, SConstants.BlockType type, SConstants.BlockSubType subType, SConstants.BlockLabel label, int startOffset, int endOffset, java.lang.Object startRef, java.lang.Object endRef)
Creates a new block.

Method Summary

int	getEndOffset() Gets the end offset for this block.
java.lang.Object	getEndRef() Gets the reference to an object of interest associated with the end of the block.
SConstants.BlockLabel	getLabel() Gets the block label.
int	getStartOffset() Gets the start offset for this block.
java.lang.Object	getStartRef() Gets the reference to an object of interest associated with the start of the block.
SConstants.BlockSubType	getSubType() Gets the block subtype.
Block[]	getSuccessors(SConstants.BlockType type, SConstants.BlockSubType subType) Gets the successors of this block which are of a given type and subtype.
SConstants.BlockType	getType() Gets the block type.
void	setEndOffset(int i) Sets the end offset variable to the given value.
void	setEndRef(java.lang.Object ref) Sets a reference to an object of interest to be associated with the end of the block.
void	setLabel(SConstants.BlockLabel bl) Sets the block label to the given value.
void	setStartOffset(int i) Sets the start offset variable to the given value.
void	setStartRef(java.lang.Object ref) Sets a reference to an object of interest to be associated with the start of the block.
void	setSubType(SConstants.BlockSubType bst) Sets the block subtype to the given value.
void	setType(SConstants.BlockType bt) Sets the block type to the given value.
java.lang.String	toString() Returns a string representation of this block in the form: (nodeID, (nodeType, nodeSubType, nodeLabel), [startOffset, endOffset]).

Methods inherited from class sofya.graphs.Node

addPredecessor, addSuccessor, getID, getPredecessorCount, getPredecessors, getPredecessors, getPredecessorsList, getSuccessorCount, getSuccessors, getSuccessors, getSuccessorsList, main, removePredecessor, removeSuccessor, setID

Methods inherited from class java.lang.Object

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

Field Detail

type

protected SConstants.BlockType type

The integer mapping to the type of this block.

subType

protected SConstants.BlockSubType subType

The integer mapping to the subtype of this block.

label

protected SConstants.BlockLabel label

The character label for the node type of this block.

startOffset

protected int startOffset

The start offset of this block.

endOffset

protected int endOffset

The end offset of this block.

startRef

protected java.lang.Object startRef

Reference to a relevant entity at the start of the block. This field is not preserved when the CFG is written to file.

endRef

protected java.lang.Object endRef

Reference to a relevant entity at the end of the block. This field is not preserved when the CFG is written to file.

ZL_ARRAY

public static final Block[] ZL_ARRAY

Zero-length block array useful for specifying array cast types to methods such Node.getSuccessors(Node[]).

Constructor Detail

Block

public Block()

Creates a new block with fields initialized to default values.

Block

public Block(int id)

Creates a new block with a given ID and all other fields initialized to default values.

Parameters:

id - ID to be associated with the new block.

Block

public Block(int id,
             SConstants.BlockType type,
             SConstants.BlockSubType subType)

Creates a new block with a given ID, type, and sub-type. Other fields are initialized to default values.

Parameters:

id - ID to be associated with the new block.

type - Main type of the new block.

subType - Secondary type of the new block.

Block

public Block(int id,
             SConstants.BlockType type,
             SConstants.BlockSubType subType,
             SConstants.BlockLabel label)

Creates a new block.

Parameters:

id - ID to be associated with the new block.

type - Main type of the new block.

subType - Secondary type of the new block.

label - Label (character) associated with the new block.

Block

public Block(int id,
             SConstants.BlockType type,
             SConstants.BlockSubType subType,
             SConstants.BlockLabel label,
             int startOffset,
             int endOffset)

Creates a new block.

Parameters:

id - ID to be associated with the new block.

type - Main type of the new block.

subType - Secondary type of the new block.

label - Label (character) associated with the new block.

startOffset - Offset of the first bytecode instruction in the new block.

endOffset - Offset of the last bytecode instruction in the new block.

Block

public Block(int id,
             SConstants.BlockType type,
             SConstants.BlockSubType subType,
             SConstants.BlockLabel label,
             int startOffset,
             int endOffset,
             java.lang.Object startRef,
             java.lang.Object endRef)

Creates a new block.

Parameters:

id - ID to be associated with the new block.

type - Main type of the new block.

subType - Secondary type of the new block.

label - Label (character) associated with the new block.

startOffset - Offset of the first bytecode instruction in the new block.

startRef - Reference to an object with some meaningful correlation to the start of the new block; typically used to reference the BCEL instruction handle of the first instruction in the block.

endRef - Reference to an object with some meaningful correlation to the end of the new block; typically used to reference the BCEL instruction handle of the last instruction in the block.

Method Detail

setType

public void setType(SConstants.BlockType bt)

Sets the block type to the given value.

Parameters:

bt - Block type to assign to this block.

getType

public SConstants.BlockType getType()

Gets the block type.

Returns:

The block type to which this block has been set.

setSubType

public void setSubType(SConstants.BlockSubType bst)

Sets the block subtype to the given value.

Parameters:

bst - Block subtype to assign to this block.

getSubType

public SConstants.BlockSubType getSubType()

Gets the block subtype.

Returns:

The block subtype to which this block has been set.

setLabel

public void setLabel(SConstants.BlockLabel bl)

Sets the block label to the given value.

Parameters:

bl - Label which this block should be assigned .

getLabel

public SConstants.BlockLabel getLabel()

Gets the block label.

Returns:

The label which has been assigned to this block.

setStartOffset

public void setStartOffset(int i)

Sets the start offset variable to the given value.

Parameters:

i - Integer representing the new start offset for this block.

getStartOffset

public int getStartOffset()

Gets the start offset for this block.

Returns:

Integer representing the start offset for this block.

setEndOffset

public void setEndOffset(int i)

Sets the end offset variable to the given value.

Parameters:

i - Integer representing the new end offset for this block.

getEndOffset

public int getEndOffset()

Gets the end offset for this block.

Returns:

Integer representing the end offset for this block.

setStartRef

public void setStartRef(java.lang.Object ref)

Sets a reference to an object of interest to be associated with the start of the block.

For example, the CFG class stores a reference to the BCEL InstructionHandle which represents the beginning of the block to improve the performance of the cfInstrumentor.

Parameters:

ref - Reference to object to be associated with the start of the block.

getStartRef

public java.lang.Object getStartRef()

Gets the reference to an object of interest associated with the start of the block.

Returns:

Reference to an object associated with the start of the block.

setEndRef

public void setEndRef(java.lang.Object ref)

Sets a reference to an object of interest to be associated with the end of the block.

For example, the CFG class stores a reference to the BCEL InstructionHandle which represents the end of the block to improve the performance of the cfInstrumentor.

Parameters:

ref - Reference to object to be associated with the end of the block.

getEndRef

public java.lang.Object getEndRef()

Gets the reference to an object of interest associated with the end of the block.

Returns:

Reference to an object associated with the end of the block.

getSuccessors

public Block[] getSuccessors(SConstants.BlockType type,
                             SConstants.BlockSubType subType)

Gets the successors of this block which are of a given type and subtype.

Parameters:

type - Major type that must be matched for a successor to be returned.

subType - Subtype that must be matched for a successor to be returned.

Returns:

An array of this node's successors which are of the given type and subtype, which may have zero elements.

toString

public java.lang.String toString()

Returns a string representation of this block in the form:
(nodeID, (nodeType, nodeSubType, nodeLabel), [startOffset, endOffset]).

Overrides:

toString in class Node

Returns:

This block represented as a string.

See Also:

Node.toString()