mcs/class/Mono.CodeContracts/Mono.CodeContracts.Static.Analysis.ExpressionAnalysis/ExpressionDecoder.cs

   1 //
   2 // ExpressionDecoder.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 Mono.CodeContracts.Static.AST;
  31 using Mono.CodeContracts.Static.AST.Visitors;
  32 using Mono.CodeContracts.Static.Analysis.ExpressionAnalysis.Expressions;
  33 using Mono.CodeContracts.Static.Analysis.HeapAnalysis;
  34 using Mono.CodeContracts.Static.ControlFlow;
  35 using Mono.CodeContracts.Static.DataStructures;
  36 using Mono.CodeContracts.Static.Lattices;
  37 using Mono.CodeContracts.Static.Providers;
  38
  39 namespace Mono.CodeContracts.Static.Analysis.ExpressionAnalysis {
  40         class ExpressionDecoder<TSymbolicValue, TContext, TEdgeData> :
  41                 IILDecoder<APC, LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue, IExpressionContextProvider<LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue>, TEdgeData>,
  42                 IExpressionContextProvider<LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue>,
  43                 IExpressionContext<LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue>
  44                 where TSymbolicValue : IEquatable<TSymbolicValue>
  45                 where TContext : IValueContextProvider<TSymbolicValue>
  46                 where TEdgeData : IImmutableMap<TSymbolicValue, LispList<TSymbolicValue>> {
  47                 private readonly IILDecoder<APC, TSymbolicValue, TSymbolicValue, IValueContextProvider<TSymbolicValue>, TEdgeData> value_decoder;
  48                 private readonly ExpressionAnalysisFacade<TSymbolicValue, TContext, TEdgeData> parent;
  49                 private readonly IValueContextProvider<TSymbolicValue> underlying;
  50
  51                 public ExpressionDecoder (IILDecoder<APC, TSymbolicValue, TSymbolicValue, IValueContextProvider<TSymbolicValue>, TEdgeData> valueDecoder,
  52                                           ExpressionAnalysisFacade<TSymbolicValue, TContext, TEdgeData> parent)
  53                 {
  54                         this.value_decoder = valueDecoder;
  55                         this.parent = parent;
  56                         this.underlying = valueDecoder.ContextProvider;
  57                 }
  58
  59                 #region IExpressionContext<LabeledSymbol<APC,SymbolicValue>,SymbolicValue> Members
  60                 public LabeledSymbol<APC, TSymbolicValue> Refine (APC pc, TSymbolicValue variable)
  61                 {
  62                         return new LabeledSymbol<APC, TSymbolicValue> (pc, variable);
  63                 }
  64
  65                 public TSymbolicValue Unrefine (LabeledSymbol<APC, TSymbolicValue> expression)
  66                 {
  67                         return expression.Symbol;
  68                 }
  69
  70                 public Result Decode<Data, Result, Visitor> (LabeledSymbol<APC, TSymbolicValue> expr, Visitor visitor, Data data)
  71                         where Visitor : ISymbolicExpressionVisitor<LabeledSymbol<APC, TSymbolicValue>, LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue, Data, Result>
  72                 {
  73                         ExprDomain<TSymbolicValue> ifFound;
  74                         if (!this.parent.PreStateLookup (expr.ReadAt, out ifFound) || ifFound.IsBottom)
  75                                 return visitor.SymbolicConstant (expr, expr.Symbol, data);
  76
  77                         FlatDomain<Expr<TSymbolicValue>> aExpr = ifFound [expr.Symbol];
  78                         if (aExpr.IsNormal) {
  79                                 return aExpr.Concrete.Decode<Data, Result, ExpressionDecoderAdapter<TSymbolicValue, Data, Result, Visitor>>
  80                                         (expr.ReadAt, expr.Symbol,
  81                                          new ExpressionDecoderAdapter<TSymbolicValue, Data, Result, Visitor> (visitor), data);
  82                         }
  83
  84                         TypeNode type;
  85                         object constant;
  86                         if (this.parent.ValueLayer.ILDecoder.ContextProvider.ValueContext.IsConstant (expr.ReadAt, expr.Symbol, out type, out constant))
  87                                 return visitor.LoadConst (expr, type, constant, expr.Symbol, data);
  88
  89                         return visitor.SymbolicConstant (expr, expr.Symbol, data);
  90                 }
  91
  92                 public FlatDomain<TypeNode> GetType (LabeledSymbol<APC, TSymbolicValue> expr)
  93                 {
  94                         return this.underlying.ValueContext.GetType (expr.ReadAt, expr.Symbol);
  95                 }
  96
  97                 public APC GetPC (LabeledSymbol<APC, TSymbolicValue> pc)
  98                 {
  99                         return pc.ReadAt;
 100                 }
 101
 102                 public LabeledSymbol<APC, TSymbolicValue> For (TSymbolicValue variable)
 103                 {
 104                         return new LabeledSymbol<APC, TSymbolicValue> (MethodContext.CFG.Entry, variable);
 105                 }
 106
 107                 public bool IsZero (LabeledSymbol<APC, TSymbolicValue> expression)
 108                 {
 109                         return ValueContext.IsZero (expression.ReadAt, expression.Symbol);
 110                 }
 111                 #endregion
 112
 113                 #region IILDecoder<APC,LabeledSymbol<APC,SymbolicValue>,SymbolicValue,IExpressionContextProvider<LabeledSymbol<APC,SymbolicValue>,SymbolicValue>,EdgeData> Members
 114                 public IExpressionContextProvider<LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue> ContextProvider
 115                 {
 116                         get { return this; }
 117                 }
 118
 119                 public Result ForwardDecode<Data, Result, Visitor> (APC pc, Visitor visitor, Data state)
 120                         where Visitor : IILVisitor<APC, LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue, Data, Result>
 121                 {
 122                         return this.value_decoder.ForwardDecode<Data, Result, ILDecoderAdapter<TSymbolicValue, Data, Result, Visitor>>
 123                                 (pc, new ILDecoderAdapter<TSymbolicValue, Data, Result, Visitor> (visitor), state);
 124                 }
 125
 126                 public bool IsUnreachable (APC pc)
 127                 {
 128                         return this.parent.IsUnreachable (pc);
 129                 }
 130
 131                 public TEdgeData EdgeData (APC from, APC to)
 132                 {
 133                         return this.parent.ValueLayer.ILDecoder.EdgeData (from, to);
 134                 }
 135                 #endregion
 136
 137                 #region Implementation of IMethodContextProvider<Field,Method>
 138                 public IMethodContext MethodContext
 139                 {
 140                         get { return this.underlying.MethodContext; }
 141                 }
 142                 #endregion
 143
 144                 #region Implementation of IStackContextProvider<Field,Method>
 145                 public IStackContext StackContext
 146                 {
 147                         get { return this.underlying.StackContext; }
 148                 }
 149                 #endregion
 150
 151                 #region Implementation of IValueContextProvider<Local,Parameter,Method,Field,Type,SymbolicValue>
 152                 public IValueContext<TSymbolicValue> ValueContext
 153                 {
 154                         get { return this.underlying.ValueContext; }
 155                 }
 156                 #endregion
 157
 158                 #region Implementation of IExpressionContextProvider<Local,Parameter,Method,Field,Type,ExternalExpression<APC,SymbolicValue>,SymbolicValue>
 159                 public IExpressionContext<LabeledSymbol<APC, TSymbolicValue>, TSymbolicValue> ExpressionContext
 160                 {
 161                         get { return this; }
 162                 }
 163                 #endregion
 164         }
 165 }