soot.jimple.toolkits.scalar.pre

Class BusyCodeMotion

java.lang.Object

soot.Transformer

soot.BodyTransformer

soot.jimple.toolkits.scalar.pre.BusyCodeMotion

public class BusyCodeMotion
extends BodyTransformer

Performs a partial redundancy elimination (= code motion). This is done, by moving everycomputation as high as possible (it is easy to show, that they are computationally optimal), and then replacing the original computation by a reference to this new high computation. This implies, that we introduce many new helper-variables (that can easily be eliminated afterwards).
In order to catch every redundant expression, this transformation must be done on a graph without critical edges. Therefore the first thing we do, is removing them. A subsequent pass can then easily remove the synthetic nodes we have introduced.
The term "busy" refers to the fact, that we always move computations as high as possible. Even, if this is not necessary.

See Also:

CriticalEdgeRemover

Constructor Summary

Constructors

Constructor and Description
BusyCodeMotion(Singletons.Global g)

Method Summary

Modifier and Type	Method and Description
protected void	internalTransform(Body b, java.lang.String phaseName, java.util.Map opts) performs the busy code motion.
static BusyCodeMotion	v()

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

BusyCodeMotion

public BusyCodeMotion(Singletons.Global g)

Method Detail

v

public static BusyCodeMotion v()

internalTransform

protected void internalTransform(Body b,
                                 java.lang.String phaseName,
                                 java.util.Map opts)

performs the busy code motion.

Specified by:

internalTransform in class BodyTransformer

Parameters:

b - the body on which to apply the transformation

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

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