scale.backend.trips2
Class PhiInstruction

java.lang.Object
  scale.backend.Instruction
      scale.backend.trips2.TripsInstruction
          scale.backend.trips2.PhiInstruction

All Implemented Interfaces:

java.lang.Cloneable

public class PhiInstruction
extends TripsInstruction

This class represents pseudo instruction Phi for building SSA form.

$Id: PhiInstruction.java,v 1.16 2007-05-01 20:14:42 asmith Exp $

Copyright 2005 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Field Summary

protected int	numOperands the number of operands
protected int[]	operands the operands
protected int	ra the destination register

Fields inherited from class scale.backend.trips2.TripsInstruction

definesPredicate, numPredicates, predicatedOnTrue, predicates

Constructor Summary

PhiInstruction(int ra, int numOperands)
Create a new Phi instruction.

Method Summary

void	assembler(Assembler asm, Emit emit) Insert the assembler representation of the instruction into the output stream.
boolean	canBeDeleted(RegisterSet registers) Return true if the instruction can be deleted without changing program semantics.
static int	created() Return the number of instances of this class created.
boolean	defs(int register, RegisterSet registers) Return true if the instruction sets the register
int	ehash() Return a hash code that can be used to determine equivalence.
int	getCopyDest() Return the destination register of a copy instruction.
int	getCopySrc() Return the source register of a copy instruction.
int	getDestRegister() Return the destination register.
int	getOpcode() Return the instruction opcode.
int[]	getOperands() Return the operands.
int	getRa() Return the ra field.
int[]	getSrcRegisters() This routine returns the source registers for an instruction.
boolean	independent(Instruction inst, RegisterSet registers) Return true if this instruction is independent of the specified instruction.
int	instructionSize() Return the number of bytes required for the EnterInstruction.
boolean	isCopy() Return true if the instruction copies a value from one register to another without modification.
boolean	isPhi() Return true if this is a phi instruction.
void	nullify(RegisterSet rs) Mark the instruction so that it is not used.
void	remapDestRegister(int oldReg, int newReg) Map the registers defined in the instruction as destinations to the specified register.
void	remapRegisters(int[] map) Map the registers used in the instruction to the specified registers.
void	remapSrcRegister(int oldReg, int newReg) Map the registers used in the instruction as sources to the specified register.
protected void	setOperand(int newOperand, int position) Change the specified operand.
void	specifyRegisterUsage(RegisterAllocator rs, int index, int strength) Specify the registers used by this instruction.
java.lang.String	toString() Return a string representation of the instruction.
boolean	uses(int register, RegisterSet registers) Return true if the instruction uses the register.

Methods inherited from class scale.backend.trips2.TripsInstruction

definesPredicate, formatOpcode, formatOpcode, formatOpcode, formatRa, getBBID, getLoopNumber, getPredicate, getPredicates, isPredicated, isPredicatedOnTrue, numPredicates, removePredicates, setBBID, setDefinesPredicate, setLoopNumber, setPredicate, setPredicate, setPredicatedOnTrue, setPredicates, setPredicates

Methods inherited from class scale.backend.Instruction

clone, copy, getExecutionCycles, getFunctionalUnit, getNext, getTag, isBranch, isLabel, isLoad, isMandatory, isMarker, isPrefetch, isSpillInstruction, isSpillLoadPoint, isSpillStorePoint, isStore, markSpillInstruction, mods, nullified, setMandatory, setNext, setsSpecialReg, setTag, specifyNotSpillLoadPoint, specifySpillStorePoint

Methods inherited from class java.lang.Object

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

Field Detail

ra

protected int ra

the destination register

operands

protected int[] operands

the operands

numOperands

protected int numOperands

the number of operands

Constructor Detail

PhiInstruction

public PhiInstruction(int ra,
                      int numOperands)

Create a new Phi instruction.

Parameters:

ra - specifies the destination register

numOperands - specifies the number of operands

Method Detail

created

public static int created()

Return the number of instances of this class created.

remapRegisters

public void remapRegisters(int[] map)

Map the registers used in the instruction to the specified registers.

Overrides:

remapRegisters in class TripsInstruction

Parameters:

map - maps from the virtual register to real register

remapSrcRegister

public void remapSrcRegister(int oldReg,
                             int newReg)

Map the registers used in the instruction as sources to the specified register. If the register is not used as a source register, no change is made.

Overrides:

remapSrcRegister in class TripsInstruction

Parameters:

oldReg - is the previous source register

newReg - is the new source register

remapDestRegister

public void remapDestRegister(int oldReg,
                              int newReg)

Map the registers defined in the instruction as destinations to the specified register. If the register is not used as a destination register, no change is made.

Specified by:

remapDestRegister in class Instruction

Parameters:

oldReg - is the previous destination register

newReg - is the new destination register

getOpcode

public int getOpcode()

Return the instruction opcode.

Specified by:

getOpcode in class Instruction

getRa

public int getRa()

Return the ra field.

getDestRegister

public int getDestRegister()

Return the destination register.

Overrides:

getDestRegister in class Instruction

setOperand

protected void setOperand(int newOperand,
                          int position)

Change the specified operand.

getSrcRegisters

public int[] getSrcRegisters()

This routine returns the source registers for an instruction. Null is returned if there are no source registers.

Overrides:

getSrcRegisters in class TripsInstruction

getOperands

public int[] getOperands()

Return the operands.

specifyRegisterUsage

public void specifyRegisterUsage(RegisterAllocator rs,
                                 int index,
                                 int strength)

Specify the registers used by this instruction.

Overrides:

specifyRegisterUsage in class TripsInstruction

Parameters:

rs - is the register set in use

index - is an index associated with the instruction

strength - is the importance of the instruction

See Also:

RegisterAllocator.useRegister(int,int,int), RegisterAllocator.defRegister(int,int)

uses

public boolean uses(int register,
                    RegisterSet registers)

Return true if the instruction uses the register.

Overrides:

uses in class TripsInstruction

defs

public boolean defs(int register,
                    RegisterSet registers)

Return true if the instruction sets the register

Overrides:

defs in class Instruction

independent

public boolean independent(Instruction inst,
                           RegisterSet registers)

Return true if this instruction is independent of the specified instruction. If instructions are independent, than one instruction can be moved before or after the other instruction without changing the semantics of the program.

Overrides:

independent in class TripsInstruction

Parameters:

inst - is the specified instruction

instructionSize

public int instructionSize()

Return the number of bytes required for the EnterInstruction.

Specified by:

instructionSize in class Instruction

canBeDeleted

public boolean canBeDeleted(RegisterSet registers)

Return true if the instruction can be deleted without changing program semantics.

Overrides:

canBeDeleted in class Instruction

nullify

public void nullify(RegisterSet rs)

Mark the instruction so that it is not used.

Overrides:

nullify in class TripsInstruction

isCopy

public boolean isCopy()

Return true if the instruction copies a value from one register to another without modification. Transfers between integer and floating point registers are not considered to be copy instructions.

Overrides:

isCopy in class Instruction

getCopySrc

public int getCopySrc()

Return the source register of a copy instruction.

Overrides:

getCopySrc in class Instruction

getCopyDest

public int getCopyDest()

Return the destination register of a copy instruction.

Overrides:

getCopyDest in class Instruction

isPhi

public boolean isPhi()

Return true if this is a phi instruction.

Overrides:

isPhi in class Instruction

ehash

public int ehash()

Return a hash code that can be used to determine equivalence.
The hash code does not include predicates or the destination register.

Overrides:

ehash in class Instruction

assembler

public void assembler(Assembler asm,
                      Emit emit)

Insert the assembler representation of the instruction into the output stream.

Specified by:

assembler in class Instruction

toString

public java.lang.String toString()

Return a string representation of the instruction.

Overrides:

toString in class java.lang.Object