134 lines
4.9 KiB
C#
134 lines
4.9 KiB
C#
//
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// ExpressionAssertDischarger.cs
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//
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// Authors:
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// Alexander Chebaturkin (chebaturkin@gmail.com)
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//
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// Copyright (C) 2011 Alexander Chebaturkin
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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using System;
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using Mono.CodeContracts.Static.AST;
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using Mono.CodeContracts.Static.AST.Visitors;
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using Mono.CodeContracts.Static.ControlFlow;
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using Mono.CodeContracts.Static.Lattices;
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namespace Mono.CodeContracts.Static.Analysis.NonNull {
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struct ExpressionAssertDischarger<E, V>
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: ISymbolicExpressionVisitor<E, E, V, bool, FlatDomain<bool>>
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where E : IEquatable<E>
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where V : IEquatable<V> {
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private readonly Analysis<E, V> analysis;
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private readonly APC pc;
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public ExpressionAssertDischarger(Analysis<E, V> analysis, APC pc)
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{
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this.analysis = analysis;
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this.pc = pc;
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}
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private IExpressionContextProvider<E, V> ContextProvider
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{
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get { return this.analysis.ContextProvider; }
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}
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#region Implementation of IExpressionILVisitor<Expression,Expression,Variable,bool,ProofOutcome>
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private FlatDomain<bool> Recurse(bool polarity, E expr)
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{
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return this.ContextProvider.ExpressionContext.Decode<bool, FlatDomain<bool>, ExpressionAssertDischarger<E, V>>(expr, this, polarity);
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}
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public FlatDomain<bool> Binary(E orig, BinaryOperator op, V dest, E operand1, E operand2, bool polarity)
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{
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switch (op) {
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case BinaryOperator.Ceq:
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case BinaryOperator.Cobjeq:
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if (this.ContextProvider.ExpressionContext.IsZero (operand2) || this.ContextProvider.ExpressionContext.IsZero (operand1))
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return this.Recurse (!polarity, operand1);
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return ProofOutcome.Top;
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case BinaryOperator.Cne_Un:
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if (this.ContextProvider.ExpressionContext.IsZero(operand2) || this.ContextProvider.ExpressionContext.IsZero(operand1))
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return this.Recurse (polarity, operand1);
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return ProofOutcome.Top;
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default:
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return this.SymbolicConstant (orig, this.ContextProvider.ExpressionContext.Unrefine (orig), polarity);
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}
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}
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public FlatDomain<bool> Isinst(E orig, TypeNode type, V dest, E obj, bool polarity)
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{
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if (!polarity)
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return this.analysis.IsNull (this.pc, dest);
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FlatDomain<bool> outcome = this.analysis.IsNonNull(this.pc, dest);
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return outcome.IsTrue() ? outcome : this.Recurse (true, obj);
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}
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public FlatDomain<bool> LoadNull(E orig, V dest, bool polarity)
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{
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return polarity ? ProofOutcome.False : ProofOutcome.True;
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}
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public FlatDomain<bool> LoadConst(E orig, TypeNode type, object constant, V dest, bool polarity)
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{
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var isConstantEqualZero = constant is int && (int) constant == 0;
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return (isConstantEqualZero != polarity) ? ProofOutcome.True : ProofOutcome.False;
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}
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public FlatDomain<bool> Sizeof(E pc, TypeNode type, V dest, bool polarity)
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{
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return polarity ? ProofOutcome.True : ProofOutcome.False;
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}
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public FlatDomain<bool> Unary(E orig, UnaryOperator op, bool unsigned, V dest, E source, bool polarity)
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{
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switch (op) {
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case UnaryOperator.Conv_i:
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case UnaryOperator.Conv_i1:
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case UnaryOperator.Conv_i2:
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case UnaryOperator.Conv_i4:
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case UnaryOperator.Conv_i8:
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case UnaryOperator.Conv_u:
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case UnaryOperator.Conv_u1:
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case UnaryOperator.Conv_u2:
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case UnaryOperator.Conv_u4:
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case UnaryOperator.Conv_u8:
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return this.Recurse (polarity, source);
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case UnaryOperator.Neg:
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return this.Recurse(polarity, source);
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case UnaryOperator.Not:
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return this.Recurse(!polarity, source);
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default:
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return this.SymbolicConstant (orig, this.ContextProvider.ExpressionContext.Unrefine (orig), polarity);
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}
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}
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#endregion
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#region Implementation of ISymbolicExpressionVisitor<Expression,Expression,Variable,bool,ProofOutcome>
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public FlatDomain<bool> SymbolicConstant(E pc, V variable, bool polarity)
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{
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return polarity ? this.analysis.IsNonNull (this.pc, variable) : this.analysis.IsNull(this.pc, variable);
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}
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#endregion
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}
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} |