scale.clef.type
Class VoidType

java.lang.Object
  scale.common.Root
      scale.clef.Node
          scale.clef.type.Type
              scale.clef.type.VoidType

All Implemented Interfaces:

AnnotationInterface, DisplayNode

public class VoidType
extends Type

This class represents the void type in C and is used to represent the absence of a type.

$Id: VoidType.java,v 1.39 2007-03-21 13:32:01 burrill Exp $

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

Field Summary

static VoidType

type There is only one void type.

Method Summary

int	alignment(Machine machine) Calculate the alignment needed for this data type.
boolean	equivalent(Type t) Return true because all void types are equivalent.
boolean	isVoidType() Return true if type represents no type.
long	memorySize(Machine machine) Calculate how many addressable memory units are needed to represent the type.
long	numberOfElements() Return the number of elements represented by this type which is 0 for void.
VoidType	returnVoidType() Return if this is a VoidType, return this.
java.lang.String	toString()
java.lang.String	toStringSpecial() This method allows sub-classes to provide class specific stuff to the string.
void	visit(Predicate p) Process a node by calling its associated routine.
void	visit(TypePredicate p) Process a node by calling its associated routine.

Methods inherited from class scale.clef.type.Type

canBeInRegister, cleanup, elementSize, getCompleteType, getCoreType, getDisplayColorHint, getDisplayLabel, getDisplayShapeHint, getEquivalentType, getNonAttributeType, getNonConstType, getPointedTo, getPointedToCore, getRank, getSignedType, getTag, getType, isAggregateType, isAllocArrayType, isArrayType, isAtomicType, isAttributeSet, isBooleanType, isCharacterType, isClassType, isComplexType, isCompositeType, isConst, isEnumerationType, isFixedArrayType, isFloatType, isFortranCharType, isIncompleteType, isIntegerType, isNamedType, isNumericType, isPointerType, isProcedureType, isRealType, isRefType, isRestricted, isSigned, isUnionType, isVolatile, mapTypeToCString, mapTypeToF77String, memorySizeAsInt, nextVisit, precedence, registerType, returnAggregateType, returnAllocArrayType, returnArrayType, returnAtomicType, returnBooleanType, returnCharacterType, returnComplexType, returnCompositeType, returnEnumerationType, returnFixedArrayType, returnFloatType, returnFortranCharType, returnIncompleteType, returnIntegerType, returnNumericType, returnPointerType, returnProcedureType, returnRealType, returnRecordType, returnRefType, returnSignedIntegerType, returnUnionType, returnUnsignedIntegerType, setTag, setVisited, specifyCanBeInRegister, toStringShort, visited

Methods inherited from class scale.clef.Node

getChild, getDecl, getSourceLineNumber, numChildren, setAnnotationLevel, setReportLevel, setSourceLineNumber, 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

Field Detail

type

public static final VoidType type

There is only one void type.

Method Detail

isVoidType

public boolean isVoidType()

Return true if type represents no type.

Overrides:

isVoidType in class Type

returnVoidType

public final VoidType returnVoidType()

Description copied from class: Type

Return if this is a VoidType, return this. Otherwise, return null.

Overrides:

returnVoidType in class Type

toString

public java.lang.String toString()

Overrides:

toString in class Type

toStringSpecial

public java.lang.String toStringSpecial()

Description copied from class: Node

This method allows sub-classes to provide class specific stuff to the string.

Overrides:

toStringSpecial in class Node

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 Type

See Also:

Predicate

visit

public void visit(TypePredicate p)

Description copied from class: Type

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 type class has a visit(TypePredicate 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 TypePredicate 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 Type

See Also:

TypePredicate

equivalent

public boolean equivalent(Type t)

Return true because all void types are equivalent.

Specified by:

equivalent in class Type

numberOfElements

public long numberOfElements()

Return the number of elements represented by this type which is 0 for void.

Overrides:

numberOfElements in class Type

memorySize

public long memorySize(Machine machine)

Calculate how many addressable memory units are needed to represent the type.

Specified by:

memorySize in class Type

Parameters:

machine - is the machine-specific data machine

Returns:

the number of addressable memory units required to represent this type

alignment

public int alignment(Machine machine)

Calculate the alignment needed for this data type.

Specified by:

alignment in class Type