edu.jmu.decaf

Class PeepholeOptimizer

java.lang.Object

edu.jmu.decaf.PeepholeOptimizer

public class PeepholeOptimizer
extends Object

Performs several basic peephole optimizations on an ILOC program. Original code written by Steven Young, CS 480 honors student.

Constructor Summary

Constructors

Constructor and Description
PeepholeOptimizer()

Method Summary

Modifier and Type	Method and Description
void	process(ILOCProgram program)
void	removeChainedJump(ILOCFunction func) Replaces instructions of the form: jmp lX [...] lX: jmp lY with jmp lY [...] lX: jmp lY
void	removeIdentityAddAndMult(ILOCFunction func) Replaces instructions of the form: addI rX, 0 => rY with i2i rX => rY and Replaces instructions of the form: multI rX, 1 => rY with i2i rX => rY Removes instructions of the form: addI rX, 0 => rX Removes instructions of the form: multI rX, 1 => rX
void	removeUselessCopies(ILOCFunction func) Removes instructions of the form: i2i rX -> rX
void	replaceOneLineJumps(ILOCFunction func) Removes jump in code of the form: jmp lX lX: [...]
void	storeLoadOptimize(ILOCFunction func) (CASE 1) Replaces code of the form: storeAI rX -> bp + offset load bp + offset -> rY with storeAI rX -> bp + offset i2i rX -> rY (CASE 2) Replaces code of the form: storeAI rX => BP+offset load BP+offset => rX with storeAI rX => BP+offset

Methods inherited from class java.lang.Object

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

Constructor Detail

PeepholeOptimizer

public PeepholeOptimizer()

Method Detail

process

public void process(ILOCProgram program)

storeLoadOptimize

public void storeLoadOptimize(ILOCFunction func)

(CASE 1) Replaces code of the form: storeAI rX -> bp + offset load bp + offset -> rY with storeAI rX -> bp + offset i2i rX -> rY (CASE 2) Replaces code of the form: storeAI rX => BP+offset load BP+offset => rX with storeAI rX => BP+offset

Parameters:

func - - ILOCFunction to be optimized

replaceOneLineJumps

public void replaceOneLineJumps(ILOCFunction func)

Removes jump in code of the form: jmp lX lX: [...]

Parameters:

func - - ILOCFunction to be optimized

removeUselessCopies

public void removeUselessCopies(ILOCFunction func)

Removes instructions of the form: i2i rX -> rX

Parameters:

func - - ILOCFunction to be optimized

removeIdentityAddAndMult

public void removeIdentityAddAndMult(ILOCFunction func)

Replaces instructions of the form: addI rX, 0 => rY with i2i rX => rY and Replaces instructions of the form: multI rX, 1 => rY with i2i rX => rY Removes instructions of the form: addI rX, 0 => rX Removes instructions of the form: multI rX, 1 => rX

Parameters:

func - - ILOCFunction to be optimized

removeChainedJump

public void removeChainedJump(ILOCFunction func)

Replaces instructions of the form: jmp lX [...] lX: jmp lY with jmp lY [...] lX: jmp lY

Parameters:

func - - ILOCFunction to be optimized