114 lines
3.9 KiB
C#
114 lines
3.9 KiB
C#
//
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// SimpleLogicInference.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.Analysis;
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using Mono.CodeContracts.Static.Analysis.Numerical;
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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.Proving {
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class SimpleLogicInference<Expression, Variable> : BasicFacts<Expression, Variable> {
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public SimpleLogicInference (IExpressionContextProvider<Expression, Variable> contextProvider, IFactBase<Variable> factBase, Predicate<APC> isUnreachable)
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: base (contextProvider, factBase, isUnreachable)
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{
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}
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public override FlatDomain<bool> IsNull(APC pc, BoxedExpression expr)
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{
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Variable v;
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if (TryVariable (expr, out v)) {
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FlatDomain<bool> proofOutcome = this.FactBase.IsNull(pc, v);
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if (!proofOutcome.IsTop)
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return proofOutcome;
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}
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if (expr.IsConstant) {
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object constant = expr.Constant;
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if (constant == null)
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return ProofOutcome.True;
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if (constant is string)
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return ProofOutcome.False;
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long? longValue = constant.ConvertToLong ();
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if (longValue.HasValue)
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return longValue == 0 ? ProofOutcome.True : ProofOutcome.False;
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return ProofOutcome.Top;
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}
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BinaryOperator op;
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BoxedExpression left;
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BoxedExpression right;
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if (expr.IsBinaryExpression (out op, out left, out right)) {
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if ((op == BinaryOperator.Ceq || op == BinaryOperator.Cobjeq) && IsNull (pc, right).IsTrue ())
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return IsNonNull (pc, left);
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if (op == BinaryOperator.Cne_Un && IsNull (pc, right).IsTrue ())
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return IsNull (pc, left);
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}
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return ProofOutcome.Top;
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}
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public override FlatDomain<bool> IsNonNull(APC pc, BoxedExpression expr)
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{
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Variable v;
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if (TryVariable (expr, out v)) {
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FlatDomain<bool> proofOutcome = this.FactBase.IsNonNull(pc, v);
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if (!proofOutcome.IsTop)
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return proofOutcome;
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}
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if (expr.IsConstant) {
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object constant = expr.Constant;
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if (constant == null)
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return ProofOutcome.False;
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if (constant is string)
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return ProofOutcome.True;
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long? longValue = constant.ConvertToLong();
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if (longValue.HasValue)
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return longValue != 0 ? ProofOutcome.True : ProofOutcome.False;
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return ProofOutcome.Top;
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}
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BinaryOperator op;
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BoxedExpression left;
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BoxedExpression right;
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if (expr.IsBinaryExpression (out op, out left, out right)) {
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if ((op == BinaryOperator.Ceq || op == BinaryOperator.Cobjeq) && IsNull (pc, right).IsTrue ())
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return IsNull (pc, left);
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if (op == BinaryOperator.Cne_Un && IsNull (pc, right).IsTrue ())
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return IsNonNull (pc, left);
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}
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return ProofOutcome.Top;
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}
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}
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}
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