org.jikesrvm.compilers.baseline

Class BasicBlock

java.lang.Object

org.jikesrvm.compilers.baseline.BasicBlock

final class BasicBlock
extends Object

Structure to describe the basic blocks of the byte code Used in calculating stack map and local variable map for the garbage collector.

Field Summary

Fields

Modifier and Type	Field and Description
private int	blockNumber ID number (index into block array)
private int	end ending byte in byte code array
(package private) static int	EXITBLOCK
(package private) static byte	INJSR
(package private) static byte	JSRENTRY
(package private) static byte	JSREXIT
(package private) static byte	METHODENTRY
(package private) static int	NOTBLOCK
private short	pred1
private short	pred2
private int	predcount number of preceding basic blocks
private short[]	restPredecessors list of rest preceding basic blocks
private int	start starting byte in byte code array
(package private) static int	STARTBBNUMBER
(package private) static int	STARTPREDSIZE
private byte	state additional state info for jsr handling, and other flags
(package private) static byte	TRYBLOCK
(package private) static byte	TRYHANDLERSTART
(package private) static byte	TRYSTART

Constructor Summary

Constructors

Constructor and Description
BasicBlock(int startval, int bn) This should be called only from the factory.
BasicBlock(int startval, int endval, int blockNumber) This should be used when building the EXIT block EXIT is likely to have several predecessors.

Method Summary

Modifier and Type	Method and Description
(package private) void	addPredecessor(BasicBlock predbb)
(package private) void	addUniquePredecessor(BasicBlock predbb) This method first checks if a block is already on the predecessor list.
(package private) int	getBlockNumber()
(package private) int	getEnd()
(package private) int[]	getPredecessors()
(package private) int	getStart()
(package private) byte	getState()
(package private) boolean	isInJSR()
(package private) boolean	isJSREntry()
(package private) boolean	isJSRExit()
(package private) boolean	isMethodEntry()
(package private) boolean	isTryBlock()
(package private) boolean	isTryHandlerStart()
(package private) boolean	isTryStart()
(package private) void	setEnd(int endval)
(package private) void	setStart(int startval)
(package private) void	setState(byte stateval)
(package private) static void	transferPredecessors(BasicBlock fromBB, BasicBlock toBB)

Methods inherited from class java.lang.Object

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

Field Detail

NOTBLOCK

static final int NOTBLOCK

See Also:

Constant Field Values

EXITBLOCK

static final int EXITBLOCK

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Constant Field Values

STARTPREDSIZE

static final int STARTPREDSIZE

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Constant Field Values

STARTBBNUMBER

static final int STARTBBNUMBER

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Constant Field Values

JSRENTRY

static final byte JSRENTRY

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Constant Field Values

JSREXIT

static final byte JSREXIT

See Also:

Constant Field Values

METHODENTRY

static final byte METHODENTRY

See Also:

Constant Field Values

TRYSTART

static final byte TRYSTART

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Constant Field Values

TRYBLOCK

static final byte TRYBLOCK

See Also:

Constant Field Values

INJSR

static final byte INJSR

See Also:

Constant Field Values

TRYHANDLERSTART

static final byte TRYHANDLERSTART

See Also:

Constant Field Values

blockNumber

private final int blockNumber

ID number (index into block array)

start

private int start

starting byte in byte code array

end

private int end

ending byte in byte code array

predcount

private int predcount

number of preceding basic blocks

pred1

private short pred1

pred2

private short pred2

restPredecessors

private short[] restPredecessors

list of rest preceding basic blocks

state

private byte state

additional state info for jsr handling, and other flags

Constructor Detail

BasicBlock

BasicBlock(int startval,
           int bn)

This should be called only from the factory.

Parameters:

startval - byte index where block starts

bn - the block's number

BasicBlock

BasicBlock(int startval,
           int endval,
           int blockNumber)

This should be used when building the EXIT block EXIT is likely to have several predecessors.

Parameters:

startval - byte index where block starts

endval - byte index where block starts

blockNumber - the block's number

Method Detail

transferPredecessors

static void transferPredecessors(BasicBlock fromBB,
                                 BasicBlock toBB)

setStart

void setStart(int startval)

setEnd

void setEnd(int endval)

setState

void setState(byte stateval)

getStart

int getStart()

getEnd

int getEnd()

getBlockNumber

int getBlockNumber()

getState

byte getState()

isJSRExit

boolean isJSRExit()

isJSREntry

boolean isJSREntry()

isInJSR

boolean isInJSR()

isMethodEntry

boolean isMethodEntry()

isTryStart

boolean isTryStart()

isTryBlock

boolean isTryBlock()

isTryHandlerStart

boolean isTryHandlerStart()

addPredecessor

void addPredecessor(BasicBlock predbb)

addUniquePredecessor

void addUniquePredecessor(BasicBlock predbb)

This method first checks if a block is already on the predecessor list. Used with try blocks being added to their catch block as predecessors.

Parameters:

predbb - block to add as predecessor

getPredecessors

int[] getPredecessors()