Robust/src/IR/TypeUtil.java

   1 package IR;
   2 import java.util.*;
   3
   4 public class TypeUtil {
   5     public static final String StringClass="String";
   6     public static final String ObjectClass="Object";
   7     public static final String StartupClass="StartupObject";
   8     State state;
   9     Hashtable supertable;
  10     Hashtable subclasstable;
  11
  12     public TypeUtil(State state) {
  13         this.state=state;
  14         createTables();
  15     }
  16
  17     public ClassDescriptor getClass(String classname) {
  18         ClassDescriptor cd=(ClassDescriptor)state.getClassSymbolTable().get(classname);
  19         return cd;
  20     }
  21
  22     private void createTables() {
  23         supertable=new Hashtable();
  24
  25         Iterator classit=state.getClassSymbolTable().getDescriptorsIterator();
  26         while(classit.hasNext()) {
  27             ClassDescriptor cd=(ClassDescriptor)classit.next();
  28             String superc=cd.getSuper();
  29             if (superc!=null) {
  30                 ClassDescriptor cd_super=getClass(superc);
  31                 supertable.put(cd,cd_super);
  32             }
  33         }
  34     }
  35
  36     public void createFullTable() {
  37         subclasstable=new Hashtable();
  38
  39         Iterator classit=state.getClassSymbolTable().getDescriptorsIterator();
  40         while(classit.hasNext()) {
  41             ClassDescriptor cd=(ClassDescriptor)classit.next();
  42             ClassDescriptor tmp=cd.getSuperDesc();
  43
  44             while(tmp!=null) {
  45                 if (!subclasstable.containsKey(tmp))
  46                     subclasstable.put(tmp,new HashSet());
  47                 HashSet hs=(HashSet)subclasstable.get(tmp);
  48                 hs.add(cd);
  49                 tmp=tmp.getSuperDesc();
  50             }
  51         }
  52     }
  53
  54     public Set getSubClasses(ClassDescriptor cd) {
  55         return (Set)subclasstable.get(cd);
  56     }
  57
  58     public ClassDescriptor getSuper(ClassDescriptor cd) {
  59         return (ClassDescriptor)supertable.get(cd);
  60     }
  61
  62     public boolean isCastable(TypeDescriptor original, TypeDescriptor casttype) {
  63         if (original.isChar()&&
  64             (casttype.isByte()||
  65              casttype.isShort()))
  66             return true;
  67
  68         if (casttype.isChar()&&
  69             (original.isByte()||
  70              original.isShort()||
  71              original.isInt()||
  72              original.isLong()||
  73              original.isFloat()||
  74              original.isDouble()))
  75             return true;
  76
  77         return false;
  78     }
  79
  80     public boolean isSuperorType(TypeDescriptor possiblesuper, TypeDescriptor cd2) {
  81         //Matching type are always okay
  82         if (possiblesuper.equals(cd2))
  83             return true;
  84
  85         //Handle arrays
  86         if (cd2.isArray()||possiblesuper.isArray()) {
  87             // Object is super class of all arrays
  88             if (possiblesuper.getSymbol().equals(ObjectClass)&&!possiblesuper.isArray())
  89                 return true;
  90
  91             // If we have the same dimensionality of arrays & both are classes, we can default to the normal test
  92             if (cd2.isClass()&&possiblesuper.isClass()
  93                 &&(possiblesuper.getArrayCount()==cd2.getArrayCount())&&
  94                 isSuperorType(possiblesuper.getClassDesc(), cd2.getClassDesc()))
  95                 return true;
  96
  97             // Object is superclass of all array classes
  98             if (possiblesuper.getSymbol().equals(ObjectClass)&&cd2.isClass()
  99                 &&(possiblesuper.getArrayCount()<cd2.getArrayCount()))
 100                 return true;
 101
 102             return false;
 103         }
 104
 105         if (possiblesuper.isClass()&&
 106              cd2.isClass())
 107             return isSuperorType(possiblesuper.getClassDesc(), cd2.getClassDesc());
 108         else if (possiblesuper.isClass()&&
 109                  cd2.isNull())
 110             return true;
 111         else if (possiblesuper.isNull())
 112             throw new Error(); //not sure when this case would occur
 113         else if (possiblesuper.isPrimitive()&&
 114                  cd2.isPrimitive()) {
 115             ///Primitive widenings from 5.1.2
 116             if (cd2.isByte()&&(possiblesuper.isByte()||possiblesuper.isShort()||
 117                                possiblesuper.isInt()||possiblesuper.isLong()||
 118                                possiblesuper.isFloat()||possiblesuper.isDouble()))
 119                 return true;
 120             if (cd2.isShort()&&(possiblesuper.isShort()||
 121                                 possiblesuper.isInt()||possiblesuper.isLong()||
 122                                 possiblesuper.isFloat()||possiblesuper.isDouble()))
 123                 return true;
 124             if (cd2.isChar()&&(possiblesuper.isChar()||
 125                                possiblesuper.isInt()||possiblesuper.isLong()||
 126                                possiblesuper.isFloat()||possiblesuper.isDouble()))
 127                 return true;
 128             if (cd2.isInt()&&(possiblesuper.isInt()||possiblesuper.isLong()||
 129                               possiblesuper.isFloat()||possiblesuper.isDouble()))
 130                 return true;
 131             if (cd2.isLong()&&(possiblesuper.isLong()||
 132                                possiblesuper.isFloat()||possiblesuper.isDouble()))
 133                 return true;
 134             if (cd2.isFloat()&&(possiblesuper.isFloat()||possiblesuper.isDouble()))
 135                 return true;
 136             if (cd2.isDouble()&&possiblesuper.isDouble())
 137
 138                 return true;
 139             if (cd2.isBoolean()&&possiblesuper.isBoolean())
 140                 return true;
 141
 142             return false;
 143         } else if (possiblesuper.isPrimitive()&&(!possiblesuper.isArray())&&
 144                    (cd2.isArray()||cd2.isPtr()))
 145             return false;
 146         else if (cd2.isPrimitive()&&(!cd2.isArray())&&
 147                  (possiblesuper.isArray()||possiblesuper.isPtr()))
 148             return false;
 149         else
 150             throw new Error();
 151     }
 152
 153
 154     public boolean isSuperorType(ClassDescriptor possiblesuper, ClassDescriptor cd2) {
 155         if (possiblesuper==cd2)
 156             return true;
 157         else
 158             return isSuper(possiblesuper, cd2);
 159     }
 160
 161     private boolean isSuper(ClassDescriptor possiblesuper, ClassDescriptor cd2) {
 162         while(cd2!=null) {
 163             cd2=getSuper(cd2);
 164             if (cd2==possiblesuper)
 165                 return true;
 166         }
 167         return false;
 168     }
 169 }