net.sf.jode.flow
Class SequentialBlock

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

public class SequentialBlock

extends StructuredBlock

A sequential block combines exactly two structured blocks to a new one. The first sub block mustn't be another sequential block, instead the second sub block should be used for this.

Constructor Summary

SequentialBlock()

Method Summary

void	checkConsistent()
void	dumpInstruction(TabbedPrintWriter writer) Print the instruction expressing this structured block.
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.
boolean	isSingleExit(StructuredBlock subBlock) Tells if the sub block is the single exit point of the current block.
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 does take the instr into account and modifies stack accordingly.
java.util.Set	propagateUsage() Propagate the used set.
void	removeOnetimeLocals() This method should remove local variables that are only written and read one time directly after another.
boolean	replaceSubBlock(StructuredBlock oldBlock, StructuredBlock newBlock) Replaces the given sub block with a new block.
void	setFirst(StructuredBlock sb)
void	setSecond(StructuredBlock sb)

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

appendBlock, contains, copyJump, doTransformations, dumpSource, fillInGenSet, flowMayBeChanged, getDeclarables, getNextBlock, getNextFlowBlock, isEmpty, moveJump, needsBraces, prependBlock, removeBlock, removeJump, removePush, replace, setFlowBlock, setJump, setSuccessors, simplify, swapJump, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

SequentialBlock

public SequentialBlock()

Method Detail

setFirst

public void setFirst(StructuredBlock sb)

setSecond

public void setSecond(StructuredBlock sb)

checkConsistent

public void checkConsistent()

Overrides:

checkConsistent in class StructuredBlock

mapStackToLocal

public VariableStack mapStackToLocal(VariableStack stack)

This does take the instr into account and modifies stack accordingly. It then calls super.mapStackToLocal.

Overrides:

mapStackToLocal in class StructuredBlock

Parameters:

stack - the stack before the instruction is called

Returns:

stack the stack afterwards.

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

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

isSingleExit

public boolean isSingleExit(StructuredBlock subBlock)

Tells if the sub block is the single exit point of the current block.

Overrides:

isSingleExit in class StructuredBlock

Parameters:

subBlock - the sub block.

Returns:

true, if the sub block is the single exit point of the current block.

propagateUsage

public java.util.Set propagateUsage()

Propagate the used set. Sequential blocks are special, because they "use" everything the first block uses. This is, because the first block can't declare something that is only visible in the first block.

Overrides:

propagateUsage in class StructuredBlock

Returns:

all locals that are used in this block or in some sub block (this is not the used set).

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.

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

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

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.