soot.jimple.toolkits.graph

Class LoopConditionUnroller

java.lang.Object

soot.Transformer

soot.BodyTransformer

soot.jimple.toolkits.graph.LoopConditionUnroller

public class LoopConditionUnroller
extends BodyTransformer

"unrolls" the condition of while/for loops.
before the first test of a while-loop, we can't be sure, if the body will be taken or not, and several optimizations (especially LCM) can't be done. In this class we try to solve this problem by unrolling the condition of the while-block: we make a copy of the condition-block, and redirect the back-edge of the while-loop to the new block.
After this transformation the edge between the original condition-block and the loop-body is only executed once (and hence suitable for LCM) and we can be sure, that the loop-body will get executed.
Exceptions are ignored (the transformation is done on a BriefBlockGraph.

Constructor Summary

Constructors

Constructor and Description
LoopConditionUnroller()

Method Summary

Modifier and Type	Method and Description
protected void	internalTransform(Body body, java.lang.String phaseName, java.util.Map<java.lang.String,java.lang.String> options) unrolls conditions.

Methods inherited from class soot.BodyTransformer

transform, transform, transform

Methods inherited from class java.lang.Object

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

Constructor Detail

LoopConditionUnroller

public LoopConditionUnroller()

Method Detail

internalTransform

protected void internalTransform(Body body,
                                 java.lang.String phaseName,
                                 java.util.Map<java.lang.String,java.lang.String> options)

unrolls conditions.

Specified by:

internalTransform in class BodyTransformer

Parameters:

body - the body on which to apply the transformation

phaseName - the phasename for this transform; not typically used by implementations.

options - the actual computed options; a combination of default options and Scene specified options.