com.claritysys.jvm.builder
Class CodeBlock

java.lang.Object
  com.claritysys.jvm.builder.CodeBlock

Direct Known Subclasses:

CatchBlock, ElseBlock, IfBlock, TryBlock

public class CodeBlock
extends java.lang.Object

Represents a code block, which defines a scope for local variables.

A block can be a a scope block, an If/Else block, or a Try/Catch/Finally block.

Variables allocated within a block go out of scope when the block ends and can have their indexes reused.

Field Summary

protected ByteArray	code The byte[] being written to.
protected CodeBuilder	codeBuilder The code builder.
protected Label	endLabel Linked list of labels to be defined at blockEnd().
protected int	endPC The PC where the block was ended.
protected LocalVariable	headVar Linked list of scoped variables.
protected int	startPC The PC where the block was started.
protected CodeBlock	surroundingBlock Link to surrounding block.
protected LocalVariable	undeclaredLocals List of undeclared LocalVariable.

Constructor Summary

CodeBlock(CodeBuilder cb)
Create a new CodeBlock.

Method Summary

void	addLocal(LocalVariable local) Add a local variable to this block's scope, to be declared in the containing CfMethod once the block is ended.
void	clearEndLabel() Clear the end label (set it to null).
void	end() End the block, noting the endPC and defining any labels specified to be defined at block end.
Label	getEndLabel() Return a label that will be defined when the block ends.
int	getEndPC()
CfMethod	getMethod() Get the method builder.
int	getStartPC()
CodeBlock	getSurroundingBlock() Return the surrounding block.
void	setCodeBuilder(CodeBuilder cb) Set the CodeBuilder, in case this block was pooled.
void	setEndLabel(Label end) Set the end label.
void	setSurroundingBlock(CodeBlock sb) Make the given block the surrounding block.
void	start() Formally start the block, noting the startPC.

Methods inherited from class java.lang.Object

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

Field Detail

startPC

protected int startPC

The PC where the block was started.

endPC

protected int endPC

The PC where the block was ended.

codeBuilder

protected CodeBuilder codeBuilder

The code builder.

code

protected ByteArray code

The byte[] being written to.

headVar

protected LocalVariable headVar

Linked list of scoped variables.

endLabel

protected Label endLabel

Linked list of labels to be defined at blockEnd().

surroundingBlock

protected CodeBlock surroundingBlock

Link to surrounding block.

undeclaredLocals

protected LocalVariable undeclaredLocals

List of undeclared LocalVariable. They are declared, because the user declared them within the code builder, but they haven't yet been declared in the CfMethod, because until the block ends it doesn't know the length of the local variable.

Constructor Detail

CodeBlock

public CodeBlock(CodeBuilder cb)

Create a new CodeBlock.

Method Detail

setCodeBuilder

public void setCodeBuilder(CodeBuilder cb)

Set the CodeBuilder, in case this block was pooled.

getMethod

public CfMethod getMethod()

Get the method builder.

getSurroundingBlock

public CodeBlock getSurroundingBlock()

Return the surrounding block.

setSurroundingBlock

public void setSurroundingBlock(CodeBlock sb)

Make the given block the surrounding block.

getEndLabel

public Label getEndLabel()

Return a label that will be defined when the block ends.

Note that the block may not have begun yet.

setEndLabel

public void setEndLabel(Label end)

Set the end label.

clearEndLabel

public void clearEndLabel()

Clear the end label (set it to null).

start

public void start()

Formally start the block, noting the startPC.

end

public void end()

End the block, noting the endPC and defining any labels specified to be defined at block end.

getStartPC

public int getStartPC()

getEndPC

public int getEndPC()

addLocal

public void addLocal(LocalVariable local)

Add a local variable to this block's scope, to be declared in the containing CfMethod once the block is ended.