scale.score.expr
Class ArrayIndexExpr

java.lang.Object
  scale.common.Root
      scale.score.Note
          scale.score.expr.Expr
              scale.score.expr.TernaryExpr
                  scale.score.expr.ArrayIndexExpr

All Implemented Interfaces:

AnnotationInterface, DisplayNode

public class ArrayIndexExpr
extends TernaryExpr

This class represents the generation of an array element address.

$Id: ArrayIndexExpr.java,v 1.22 2007-01-05 19:06:43 burrill Exp $

Copyright 2008 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Field Summary

Fields inherited from class scale.score.expr.Expr

fpReorder, SE_DOMAIN, SE_NONE, SE_OVERFLOW, SE_STATE

Constructor Summary

ArrayIndexExpr(Type t, Expr array, Expr index, Expr offset)

Method Summary

Expr	copy() Perform a deep copy of the expression tree.
int	executionCostEstimate() Return a relative cost estimate for executing the expression.
AliasAnnote	getAliasAnnote() Get the alias annotation associated with a Scribble operator.
Expr	getArray() Return the expression specifying the array.
java.lang.String	getDisplayLabel() Return a String suitable for labeling this node in a graphical display.
Expr	getIndex() Return the expression specifying the index.
Expr	getOffset() Return the expression specifying the offset.
Expr	getReference() Return the array associated with the subscript expression.
int	getReuseLevel()
boolean	isDefined(Expr lv) The given expression is defined if the ArrayIndexExpr expression is defined and the given expression is the array.
boolean	optimizationCandidate() Return true if the expression can be moved without problems.
Expr	reduce() Return a simplied equivalent expression.
void	setReuseLevel(int r)
boolean	validLValue() Return true if this expression is valid on the left side of an assignment.
void	visit(Predicate p) Process a node by calling its associated routine.

Methods inherited from class scale.score.expr.TernaryExpr

containsDeclaration, dependsOnDeclaration, equivalent, getDeclList, getExprList, getLA, getLoadExprList, getMA, getOperand, getOperandArray, getRA, loopClean, numOperands, pushOperands, recordRefs, removeRefs, removeUseDef, replaceDecl, setLA, setMA, setOperand, setRA, sideEffects, unlinkExpression, validate

Methods inherited from class scale.score.expr.Expr

addCast, addCast, canonical, changeInDataEdge, conditionalCopy, conditionalUnlinkExpression, deleteOutDataEdge, executionOrder, executionOrdinal, findCriticalChord, findLinearCoefficient, findSubscriptExpr, getAffineExpr, getAffineRepresentation, getCall, getConstantValue, getConstantValue, getCoreType, getCriticalChord, getDefExpr, getDisplayColorHint, getDisplayShapeHint, getDualExpr, getInDataEdge, getInDataEdgeArray, getLoopHeader, getLow, getLValue, getOutDataEdge, getPointedToCore, getRValue, getType, getUseDef, hasTrueFalseResult, isCast, isDefined, isLiteralExpr, isLoopInvariant, isMatchExpr, isMemoryDef, isMemRefExpr, isScalar, isSimpleExpr, mayGenerateCall, numInDataEdges, removeDualExprs, setCrossloopReuse, setOutDataEdge, setSpatialReuse, setStep, setTemporalReuse, setType, setUseDef, toStringSpecial

Methods inherited from class scale.score.Note

getChord, getEssentialUse, setAnnotationLevel, setReportLevel, toString

Methods inherited from class scale.common.Root

addAnnotation, allAnnotations, allMatchingAnnotations, getAnnotation, getDisplayName, getDisplayString, getNodeCount, getNodeID, hasAnnotation, hasEqualAnnotation, hashCode, removeAnnotation, removeAnnotations, toStringAnnotations, toStringClass, trace, trace, trace

Methods inherited from class java.lang.Object

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

Constructor Detail

ArrayIndexExpr

public ArrayIndexExpr(Type t,
                      Expr array,
                      Expr index,
                      Expr offset)

Method Detail

copy

public Expr copy()

Description copied from class: Expr

Perform a deep copy of the expression tree. By deep copy, we mean that copies are made of the expression tree.

Specified by:

copy in class Expr

Returns:

a copy of this expression

visit

public void visit(Predicate p)

Description copied from class: Note

Process a node by calling its associated routine. See the "visitor" design pattern in Design Patterns: Elements of Reusable Object-Oriented Software by E. Gamma, et al, Addison Wesley, ISBN 0-201-63361-2.

Each class has a visit(Predicate p) method. For example, in class ABC:

   public void visit(Predicate p)
   {
     p.visitABC(this);
   }
 

and the class that implements Predicate has a method

   public void visitABC(Note n)
   {
     ABC a = (ABC) n;
     ...
   }
 

Thus, the class that implements Predicate can call

   n.visit(this);
 

where n is a Note sub-class without determining which specific sub-class n is. The visit pattern basically avoids implementing a large switch statement or defining different methods in each class for some purpose.

Specified by:

visit in class Note

See Also:

Predicate

getDisplayLabel

public java.lang.String getDisplayLabel()

Description copied from class: Expr

Return a String suitable for labeling this node in a graphical display. This method should be over-ridden as it simplay returns the class name.

Specified by:

getDisplayLabel in interface DisplayNode

Overrides:

getDisplayLabel in class Expr

getArray

public final Expr getArray()

Return the expression specifying the array.

getIndex

public final Expr getIndex()

Return the expression specifying the index.

getOffset

public final Expr getOffset()

Return the expression specifying the offset.

isDefined

public boolean isDefined(Expr lv)

The given expression is defined if the ArrayIndexExpr expression is defined and the given expression is the array.

Overrides:

isDefined in class Expr

Parameters:

lv - the expression representing the array name

Returns:

true if the array is defined.

getReference

public Expr getReference()

Return the array associated with the subscript expression. We use the array name to represent the access of the array - instead of the array index value.

Overrides:

getReference in class Expr

Returns:

the array name

validLValue

public boolean validLValue()

Return true if this expression is valid on the left side of an assignment.

Overrides:

validLValue in class Expr

optimizationCandidate

public boolean optimizationCandidate()

Return true if the expression can be moved without problems. Expressions that reference global variables, non-atomic variables, etc are not optimization candidates.

Overrides:

optimizationCandidate in class TernaryExpr

setReuseLevel

public void setReuseLevel(int r)

getReuseLevel

public int getReuseLevel()

Overrides:

getReuseLevel in class Expr

getAliasAnnote

public AliasAnnote getAliasAnnote()

Get the alias annotation associated with a Scribble operator. Most Scribble operators do not have alias variables so this routine may return null. Typically, the alias variable information is attached to the declaration node associated with the load operations. However, we sometimes need to create alias variables to hold alias information that is not directly assigned to a user variable (e.g., **x).

Overrides:

getAliasAnnote in class Expr

Returns:

the alias annotation associated with the expression

reduce

public Expr reduce()

Return a simplied equivalent expression. This method may modify the original expression. This is used in the lowering of subscript expressions.

Overrides:

reduce in class Expr

See Also:

SubscriptExpr.lower()

executionCostEstimate

public int executionCostEstimate()

Return a relative cost estimate for executing the expression.

Specified by:

executionCostEstimate in class Note