coins.ssa
Class Coalescing

java.lang.Object
  coins.ssa.Coalescing

All Implemented Interfaces:

LocalTransformer, Transformer

class Coalescing

extends java.lang.Object

implements LocalTransformer

Coalescing
Perform coalescing proposed by Chaitin after the back translation to normal form. This coalesces copy-related variables whose live ranges do not interfere each other. In general, after the back translation from SSA form, there are some copy assign statements in the program. Some copy assign statements only change the names of variables, that is, they are useless. Coalescing these variables eliminates the useless copy assign statements. This optimization is done after the back translation from SSA form.

Field Summary

static int

THR The threshold of debug print

Constructor Summary

Coalescing(SsaEnvironment e)
Constructor

Method Summary

boolean	doIt(Data data, ImList args) Transform the DATA component.
boolean	doIt(Function function, ImList args) Do coalescing to the current function.
java.lang.String	name() Return the name of the transforming engine.
java.lang.String	subject() Return brief description of the tranformation.

Methods inherited from class java.lang.Object

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

Field Detail

THR

public static final int THR

The threshold of debug print

See Also:

Constant Field Values

Constructor Detail

Coalescing

public Coalescing(SsaEnvironment e)

Constructor

Parameters:

e - The environment of the SSA module

Method Detail

doIt

public boolean doIt(Data data,
                    ImList args)

Description copied from interface: LocalTransformer

Transform the DATA component.

Specified by:

doIt in interface LocalTransformer

Parameters:

data - DATA to be transformed.

args - list of optional arguments.

Returns:

true if transformation suceeded.

name

public java.lang.String name()

Description copied from interface: Transformer

Return the name of the transforming engine. Used for trace tag name.

Specified by:

name in interface Transformer

Returns:

the name of the transforming engine.

subject

public java.lang.String subject()

Description copied from interface: Transformer

Return brief description of the tranformation.

Specified by:

subject in interface Transformer

Returns:

brief description of the tranformation.

doIt

public boolean doIt(Function function,
                    ImList args)

Do coalescing to the current function.

Specified by:

doIt in interface LocalTransformer

Parameters:

function - The current fucntion

args - The list of options

Returns:

true if transformation suceeded.