net.sf.jode.flow
Class LoopBlock

java.lang.Object
  net.sf.jode.flow.StructuredBlock
      net.sf.jode.flow.LoopBlock

All Implemented Interfaces:

BreakableBlock

public class LoopBlock

extends StructuredBlock

implements BreakableBlock

This is the structured block for an Loop block.

Field Summary

static int	DOWHILE
static Expression	FALSE
static int	FOR
static int	POSSFOR
static Expression	TRUE
static int	WHILE

Constructor Summary

LoopBlock(int type, Expression cond)

Method Summary

void	checkDeclaration(java.util.Set declareSet) Check if this is an local store instruction to a not yet declared variable.
boolean	conditionMatches(CombineableOperator combinable)
boolean	doTransformations() Do simple transformation on the structuredBlock.
void	dumpInstruction(TabbedPrintWriter writer) Print the instruction expressing this structured block.
void	dumpSource(TabbedPrintWriter writer) Print the source code for this structured block.
Expression	getCondition()
java.util.Set	getDeclarables()
java.lang.String	getLabel() Returns the label of this block and creates a new label, if there wasn't a label previously.
StructuredBlock	getNextBlock(StructuredBlock subBlock) Returns the block where the control will normally flow to, when the given sub block is finished (not ignoring the jump after this block).
FlowBlock	getNextFlowBlock(StructuredBlock subBlock)
StructuredBlock[]	getSubBlocks() Returns all sub block of this structured block.
int	getType()
boolean	jumpMayBeChanged() Determines if there is a sub block, that flows through to the end of this block.
void	makeDeclaration(java.util.Set done) Make the declarations, i.e. initialize the declare variable to correct values.
VariableStack	mapStackToLocal(VariableStack stack) This is called after the analysis is completely done.
void	mergeBreakedStack(VariableStack stack) Is called by BreakBlock, to tell us what the stack can be after a break.
void	mergeContinueStack(VariableStack stack) Is called by BreakBlock, to tell us what the stack can be after a break.
void	removeLocallyDeclareable(java.util.Set set) Remove all variables from set, that we can declare inside the loop-block.
void	removeOnetimeLocals() This method should remove local variables that are only written and read one time directly after another.
void	removePush() This is called after mapStackToLocal to do the stack to local transformation.
void	replaceBreakContinue(BreakableBlock block) Replace all breaks to block with a continue to this.
boolean	replaceSubBlock(StructuredBlock oldBlock, StructuredBlock newBlock) Replaces the given sub block with a new block.
void	setBody(StructuredBlock body)
void	setBreaked() Is called by BreakBlock, to tell us that this block is breaked.
void	setCondition(Expression cond)
void	setInit(InstructionBlock initBlock)
void	setType(int type)
void	simplify()

Methods inherited from class net.sf.jode.flow.StructuredBlock

appendBlock, checkConsistent, contains, copyJump, fillInGenSet, flowMayBeChanged, getNextBlock, getNextFlowBlock, isEmpty, isSingleExit, moveJump, needsBraces, prependBlock, propagateUsage, removeBlock, removeJump, replace, setFlowBlock, setJump, setSuccessors, swapJump, toString

Methods inherited from class java.lang.Object

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

Field Detail

WHILE

public static final int WHILE

See Also:

Constant Field Values

DOWHILE

public static final int DOWHILE

See Also:

Constant Field Values

FOR

public static final int FOR

See Also:

Constant Field Values

POSSFOR

public static final int POSSFOR

See Also:

Constant Field Values

TRUE

public static final Expression TRUE

FALSE

public static final Expression FALSE

Constructor Detail

LoopBlock

public LoopBlock(int type,
                 Expression cond)

Method Detail

getNextBlock

public StructuredBlock getNextBlock(StructuredBlock subBlock)

Returns the block where the control will normally flow to, when the given sub block is finished (not ignoring the jump after this block). (This is overwritten by SequentialBlock and SwitchBlock). If this isn't called with a direct sub block, the behaviour is undefined, so take care.

Overrides:

getNextBlock in class StructuredBlock

Returns:

null, if the control flows to another FlowBlock.

getNextFlowBlock

public FlowBlock getNextFlowBlock(StructuredBlock subBlock)

Overrides:

getNextFlowBlock in class StructuredBlock

setBody

public void setBody(StructuredBlock body)

setInit

public void setInit(InstructionBlock initBlock)

conditionMatches

public boolean conditionMatches(CombineableOperator combinable)

getCondition

public Expression getCondition()

setCondition

public void setCondition(Expression cond)

getType

public int getType()

setType

public void setType(int type)

replaceSubBlock

public boolean replaceSubBlock(StructuredBlock oldBlock,
                               StructuredBlock newBlock)

Replaces the given sub block with a new block.

Overrides:

replaceSubBlock in class StructuredBlock

Parameters:

oldBlock - the old sub block.

newBlock - the new sub block.

Returns:

false, if oldBlock wasn't a direct sub block.

getSubBlocks

public StructuredBlock[] getSubBlocks()

Returns all sub block of this structured block.

Overrides:

getSubBlocks in class StructuredBlock

removeLocallyDeclareable

public void removeLocallyDeclareable(java.util.Set set)

Remove all variables from set, that we can declare inside the loop-block. This is the initializer for for-blocks.

getDeclarables

public java.util.Set getDeclarables()

Overrides:

getDeclarables in class StructuredBlock

checkDeclaration

public void checkDeclaration(java.util.Set declareSet)

Check if this is an local store instruction to a not yet declared variable. In that case mark this as declaration and return the variable.

makeDeclaration

public void makeDeclaration(java.util.Set done)

Make the declarations, i.e. initialize the declare variable to correct values. This will declare every variable that is marked as used, but not done.

Overrides:

makeDeclaration in class StructuredBlock

Parameters:

done - The set of the already declare variables.

dumpSource

public void dumpSource(TabbedPrintWriter writer)
                throws java.io.IOException

Description copied from class: StructuredBlock

Print the source code for this structured block. This handles everything that is unique for all structured blocks and calls dumpInstruction afterwards.

Overrides:

dumpSource in class StructuredBlock

Parameters:

writer - The tabbed print writer, where we print to.

Throws:

java.io.IOException

dumpInstruction

public void dumpInstruction(TabbedPrintWriter writer)
                     throws java.io.IOException

Description copied from class: StructuredBlock

Print the instruction expressing this structured block.

Specified by:

dumpInstruction in class StructuredBlock

Parameters:

writer - The tabbed print writer, where we print to.

Throws:

java.io.IOException

getLabel

public java.lang.String getLabel()

Returns the label of this block and creates a new label, if there wasn't a label previously.

Specified by:

getLabel in interface BreakableBlock

setBreaked

public void setBreaked()

Is called by BreakBlock, to tell us that this block is breaked.

Specified by:

setBreaked in interface BreakableBlock

mapStackToLocal

public VariableStack mapStackToLocal(VariableStack stack)

This is called after the analysis is completely done. It will remove all PUSH/stack_i expressions, (if the bytecode is correct).

Overrides:

mapStackToLocal in class StructuredBlock

Parameters:

stack - the stack at begin of the block

Returns:

null if there is no way to the end of this block, otherwise the stack after the block has executed.

mergeContinueStack

public void mergeContinueStack(VariableStack stack)

Is called by BreakBlock, to tell us what the stack can be after a break.

Returns:

false if the stack is inconsistent.

mergeBreakedStack

public void mergeBreakedStack(VariableStack stack)

Is called by BreakBlock, to tell us what the stack can be after a break.

Specified by:

mergeBreakedStack in interface BreakableBlock

Parameters:

stack - the stack at the break.

Returns:

false if the stack is inconsistent.

removePush

public void removePush()

Description copied from class: StructuredBlock

This is called after mapStackToLocal to do the stack to local transformation.

Overrides:

removePush in class StructuredBlock

removeOnetimeLocals

public void removeOnetimeLocals()

This method should remove local variables that are only written and read one time directly after another.
This is especially important for stack locals, that are created when there are unusual swap or dup instructions, but also makes inlined functions more pretty (but not that close to the bytecode).

Overrides:

removeOnetimeLocals in class StructuredBlock

replaceBreakContinue

public void replaceBreakContinue(BreakableBlock block)

Replace all breaks to block with a continue to this.

Parameters:

block - the breakable block where the breaks originally breaked to (Have a break now, if you didn't understand that :-).

jumpMayBeChanged

public boolean jumpMayBeChanged()

Determines if there is a sub block, that flows through to the end of this block. If this returns true, you know that jump is null.

Overrides:

jumpMayBeChanged in class StructuredBlock

Returns:

true, if the jump may be safely changed.

simplify

public void simplify()

Overrides:

simplify in class StructuredBlock

doTransformations

public boolean doTransformations()

Description copied from class: StructuredBlock

Do simple transformation on the structuredBlock.

Overrides:

doTransformations in class StructuredBlock

Returns:

true, if some transformation was done.