mcs/class/Mono.CodeContracts/Mono.CodeContracts.Static.Analysis.HeapAnalysis/AbstractType.cs

   1 //
   2 // AbstractType.cs
   3 //
   4 // Authors:
   5 //      Alexander Chebaturkin (chebaturkin@gmail.com)
   6 //
   7 // Copyright (C) 2011 Alexander Chebaturkin
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.IO;
  31 using Mono.CodeContracts.Static.AST;
  32 using Mono.CodeContracts.Static.Lattices;
  33
  34 namespace Mono.CodeContracts.Static.Analysis.HeapAnalysis {
  35         struct AbstractType : IAbstractDomainForEGraph<AbstractType>, IEquatable<AbstractType> {
  36                 public static AbstractType TopValue = new AbstractType (FlatDomain<TypeNode>.TopValue, false);
  37                 public static AbstractType BottomValue = new AbstractType (FlatDomain<TypeNode>.BottomValue, true);
  38
  39                 private FlatDomain<TypeNode> value;
  40
  41                 public AbstractType (FlatDomain<TypeNode> value, bool isZero) : this ()
  42                 {
  43                         IsZero = isZero;
  44                         this.value = value;
  45                 }
  46
  47                 public bool IsZero { get; private set; }
  48
  49                 public FlatDomain<TypeNode> Type
  50                 {
  51                         get { return this.value; }
  52                 }
  53
  54                 public TypeNode ConcreteType
  55                 {
  56                         get { return this.value.Value; }
  57                 }
  58
  59                 private static AbstractType ForManifestedFieldValue
  60                 {
  61                         get { return TopValue; }
  62                 }
  63
  64                 public AbstractType ButZero
  65                 {
  66                         get { return new AbstractType (this.value, true); }
  67                 }
  68                 public AbstractType With (FlatDomain<TypeNode> type)
  69                 {
  70                         return new AbstractType (type, this.IsZero);
  71                 }
  72
  73                 #region IAbstractDomainForEGraph<AbstractType> Members
  74                 public AbstractType Top
  75                 {
  76                         get { return new AbstractType (FlatDomain<TypeNode>.TopValue, false); }
  77                 }
  78
  79                 public AbstractType Bottom
  80                 {
  81                         get { return new AbstractType (FlatDomain<TypeNode>.BottomValue, true); }
  82                 }
  83
  84                 public bool IsTop
  85                 {
  86                         get { return !IsZero && this.value.IsTop; }
  87                 }
  88
  89                 public bool IsBottom
  90                 {
  91                         get { return IsZero && this.value.IsBottom; }
  92                 }
  93
  94             public AbstractType Join(AbstractType that)
  95             {
  96                 throw new NotImplementedException();
  97             }
  98
  99             public AbstractType Join (AbstractType that, bool widening, out bool weaker)
 100                 {
 101                         if (that.IsZero) {
 102                                 weaker = false;
 103                                 if (this.value.IsBottom)
 104                                         return new AbstractType (that.value, IsZero);
 105                                 return this;
 106                         }
 107                         if (IsZero) {
 108                                 weaker = true;
 109                                 if (that.value.IsBottom)
 110                                         return new AbstractType (this.value, that.IsZero);
 111                                 return that;
 112                         }
 113
 114                         FlatDomain<TypeNode> resultType = this.value.Join (that.value, widening, out weaker);
 115                         return new AbstractType (resultType, false);
 116                 }
 117
 118             public AbstractType Widen(AbstractType that)
 119             {
 120                 throw new NotImplementedException();
 121             }
 122
 123             public AbstractType Meet (AbstractType that)
 124                 {
 125                         return new AbstractType (this.value.Meet (that.value), IsZero || that.IsZero);
 126                 }
 127
 128                 public bool LessEqual (AbstractType that)
 129                 {
 130                         if (IsZero)
 131                                 return true;
 132                         if (that.IsZero)
 133                                 return false;
 134
 135                         return this.value.LessEqual (that.value);
 136                 }
 137
 138                 public AbstractType ImmutableVersion ()
 139                 {
 140                         return this;
 141                 }
 142
 143                 public AbstractType Clone ()
 144                 {
 145                         return this;
 146                 }
 147
 148                 public void Dump (TextWriter tw)
 149                 {
 150                         if (IsZero)
 151                                 tw.Write ("(Zero) ");
 152
 153                         this.value.Dump (tw);
 154                 }
 155
 156                 public bool HasAllBottomFields
 157                 {
 158                         get { return IsZero; }
 159                 }
 160
 161                 public AbstractType ForManifestedField ()
 162                 {
 163                         return ForManifestedFieldValue;
 164                 }
 165                 #endregion
 166
 167                 #region IEquatable<AbstractType> Members
 168                 public bool Equals (AbstractType that)
 169                 {
 170                         return this.IsZero == that.IsZero && this.value.Equals (that.value);
 171                 }
 172                 #endregion
 173
 174                 public override string ToString ()
 175                 {
 176                         return (IsZero ? "(Zero) " : "") + this.value;
 177                 }
 178         }
 179 }