leola.vm.compiler

Class Labels

java.lang.Object

leola.vm.compiler.Labels

public class Labels
extends Object

A means for managing Label generation. In general, Labels are created and stored in byte code before the final jump address is known. Upon knowledge of their jump address, they must be updated with the jump address information.

Author:

Tony

Constructor Summary

Constructors

Constructor and Description
Labels()

Method Summary

Modifier and Type	Method and Description
Label	getLabel(String labelName)
boolean	hasLabel(String labelName)
Collection<Label>	labels()
void	markLabel(BytecodeEmitter asm, String labelName, int opcode) If the label exists, it will invoke the Label.mark(int) on the existing Label.
String	nextLabelName() Generates the next sequenced labeled name
void	reconcileLabels(Instructions instructions) Reconciles the labels
void	setLabel(BytecodeEmitter asm, String labelName) If the label exists, it will invoke the Label.set() on the existing Label.
void	storeLabel(String labelName, Label label) Stores the label

Methods inherited from class java.lang.Object

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

Constructor Detail

Labels

public Labels()

Method Detail

hasLabel

public boolean hasLabel(String labelName)

Parameters:

labelName -

Returns:

true if the label exists; false otherwise

storeLabel

public void storeLabel(String labelName,
                       Label label)

Stores the label

Parameters:

labelName -

label -

getLabel

public Label getLabel(String labelName)

Parameters:

labelName -

Returns:

the Label if it exists, null otherwise

labels

public Collection<Label> labels()

Returns:

a collection of all the stored Labels

markLabel

public void markLabel(BytecodeEmitter asm,
                      String labelName,
                      int opcode)

If the label exists, it will invoke the Label.mark(int) on the existing Label. If the label does not exist, it will create it and associate it with the supplied BytecodeEmitter and invoke the Label.mark(int) on it.

Parameters:

asm -

labelName -

opcode -

setLabel

public void setLabel(BytecodeEmitter asm,
                     String labelName)

If the label exists, it will invoke the Label.set() on the existing Label. If the label does not exist, it will create it and associate it with the supplied BytecodeEmitter and invoke the Label.set() on it.

Parameters:

asm -

labelName -

nextLabelName

public String nextLabelName()

Generates the next sequenced labeled name

Returns:

the labeled name

reconcileLabels

public void reconcileLabels(Instructions instructions)

Reconciles the labels

Parameters:

instructions - the list of instructions that contain the jump labels