scale.clef.expr
Class SubscriptOp

java.lang.Object
  scale.common.Root
      scale.clef.Node
          scale.clef.expr.Expression
              scale.clef.expr.SubscriptOp

All Implemented Interfaces:

AnnotationInterface, DisplayNode

Direct Known Subclasses:

SubscriptAddressOp, SubscriptValueOp

public abstract class SubscriptOp
extends Expression

This is the base class for subscripting operations.

$Id: SubscriptOp.java,v 1.64 2007-10-04 19:58:06 burrill Exp $

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

Regardless of whether the source language uses row major or column major array ordering, the subscripts represented by an instance of this class are always in row major (C style) ordering.

There is a difference between how subscripting is represented between C and Fortran.

Array Def	Reference	C	Fortran
int x1[10]	x1	pointer to int	pointer to 1-D array of int
int (*p1)[10]	p1	pointer to 1-D array of int	NA
int x2[10][10]	x2	pointer to 1-D array of int	pointer to 2-D array of int
int (*p2)[10][10]	p2	pointer to 2-D array of int	NA

The C representation is necessary in order for pointer-arithmetic and subscripting to be interchangeable. It also requires that all C arrays be 0-origin indexed.

For Fortran, arrays can be defined using any integer origin. Therefore, in order for the proper array offset to be calculated, it is necessary for the complete array information to be available from the type of the array operand of a SubscriptOp instance.

An identical representation, as is used after parsing (SubscriptExpr, ArrayIndexExpr), cannot be used by the C parser because the C language allows both subscripting notation and pointer arithmetic to be combined in the same array access expression.

See Also:

setFortranArray(), isFortranArray()

Constructor Summary

SubscriptOp(Type type, Expression array, Vector<Expression> subscripts)

Method Summary

void	addIndex(Expression index) Add another index to the subscript expression.
void	addToIndex(int i, Expression add) Add another index to the subscript expression.
boolean	containsDeclaration(Declaration decl) Return true if this expression contains a reference to the variable.
boolean	equivalent(java.lang.Object exp) Return true if the two expressions are equivalent.
Expression	getArray() Return the array address expression.
Node	getChild(int i) Return the specified AST child of this node.
long	getConstantIndex() Return the constant linear index or a negative value if not constant.
void	getDeclList(java.util.AbstractCollection<Declaration> varList) Add all declarations referenced in this expression to the collection.
Expression	getSubscript(int i) Return the specified subscript.
protected Vector<Expression>	getSubscripts() Return the vector of index expressions.
boolean	isFortranArray() Return true if this instance is a Fortran array subscript.
int	numChildren() Return the number of AST children of this node.
int	numSubscripts() Return the number of subscripts.
protected void	setArray(Expression array) Specify the array address expression.
void	setFortranArray() Specify that this instance is a Fortran array subscript.
void	visit(Predicate p) Process a node by calling its associated routine.

Methods inherited from class scale.clef.expr.Expression

canonical, getConstantValue, getCoreType, getDisplayColorHint, getDisplayLabel, getDisplayShapeHint, getPointedToCore, getType, hasTrueFalseResult, isSimpleOp, setType, toStringSpecial

Methods inherited from class scale.clef.Node

getDecl, getSourceLineNumber, setAnnotationLevel, setReportLevel, setSourceLineNumber, toString, toString, toStringChildren

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

SubscriptOp

public SubscriptOp(Type type,
                   Expression array,
                   Vector<Expression> subscripts)

Method Detail

isFortranArray

public final boolean isFortranArray()

Return true if this instance is a Fortran array subscript.

setFortranArray

public final void setFortranArray()

Specify that this instance is a Fortran array subscript.

equivalent

public boolean equivalent(java.lang.Object exp)

Return true if the two expressions are equivalent.

Overrides:

equivalent in class Expression

visit

public void visit(Predicate p)

Description copied from class: Node

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(Node n)
   {
     ABC a = (ABC) n;
     ...
   }
 

Thus, the class that implements Predicate can call

   n.visit(this);
 

where n is a Node 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.

Overrides:

visit in class Expression

See Also:

Predicate

getArray

public final Expression getArray()

Return the array address expression.

getSubscripts

protected Vector<Expression> getSubscripts()

Return the vector of index expressions.

setArray

protected final void setArray(Expression array)

Specify the array address expression.

getChild

public Node getChild(int i)

Return the specified AST child of this node.

Overrides:

getChild in class Node

numChildren

public int numChildren()

Return the number of AST children of this node.

Overrides:

numChildren in class Node

numSubscripts

public final int numSubscripts()

Return the number of subscripts.

getSubscript

public Expression getSubscript(int i)

Return the specified subscript. Regardless of whether the source language uses row major or column major array ordering, the subscripts represented by this expression are always in row major (C style) ordering.

addIndex

public final void addIndex(Expression index)

Add another index to the subscript expression.

addToIndex

public final void addToIndex(int i,
                             Expression add)

Add another index to the subscript expression.

getConstantIndex

public long getConstantIndex()

Return the constant linear index or a negative value if not constant.

containsDeclaration

public boolean containsDeclaration(Declaration decl)

Return true if this expression contains a reference to the variable.

Overrides:

containsDeclaration in class Expression

getDeclList

public void getDeclList(java.util.AbstractCollection<Declaration> varList)

Description copied from class: Expression

Add all declarations referenced in this expression to the collection.

Specified by:

getDeclList in class Expression