public Implementation Inject(Implementation implementation, Program programInCachedSnapshot) { Contract.Requires(implementation != null && programInCachedSnapshot != null); this.programInCachedSnapshot = programInCachedSnapshot; assumptionVariableCount = 0; temporaryVariableCount = 0; currentImplementation = implementation; #region Introduce explict assumption about the precondition. var oldProc = programInCachedSnapshot.FindProcedure(currentImplementation.Proc.Name); if (oldProc != null && oldProc.DependencyChecksum != currentImplementation.Proc.DependencyChecksum && currentImplementation.ExplicitAssumptionAboutCachedPrecondition == null) { var axioms = new List <Axiom>(); var after = new List <Cmd>(); Expr assumedExpr = new LiteralExpr(Token.NoToken, false); var canUseSpecs = DependencyCollector.CanExpressOldSpecs(oldProc, Program, true); if (canUseSpecs && oldProc.SignatureEquals(currentImplementation.Proc)) { var always = Substituter.SubstitutionFromHashtable(currentImplementation.GetImplFormalMap(), true, currentImplementation.Proc); var forOld = Substituter.SubstitutionFromHashtable(new Dictionary <Variable, Expr>()); var clauses = oldProc.Requires.Select(r => Substituter.FunctionCallReresolvingApply(always, forOld, r.Condition, Program)); var conj = Expr.And(clauses, true); assumedExpr = conj != null ? FunctionExtractor.Extract(conj, Program, axioms) : new LiteralExpr(Token.NoToken, true); } if (assumedExpr != null) { var lv = new LocalVariable(Token.NoToken, new TypedIdent(Token.NoToken, string.Format("a##cached##{0}", FreshAssumptionVariableName), Type.Bool), new QKeyValue(Token.NoToken, "assumption", new List <object>(), null)); currentImplementation.InjectAssumptionVariable(lv, !canUseSpecs); var lhs = new SimpleAssignLhs(Token.NoToken, new IdentifierExpr(Token.NoToken, lv)); var rhs = LiteralExpr.And(new IdentifierExpr(Token.NoToken, lv), assumedExpr); var assumed = new AssignCmd(currentImplementation.tok, new List <AssignLhs> { lhs }, new List <Expr> { rhs }); assumed.IrrelevantForChecksumComputation = true; currentImplementation.ExplicitAssumptionAboutCachedPrecondition = assumed; after.Add(assumed); } if (CommandLineOptions.Clo.TraceCachingForTesting || CommandLineOptions.Clo.TraceCachingForBenchmarking) { using (var tokTxtWr = new TokenTextWriter("<console>", Console.Out, false, false)) { var loc = currentImplementation.tok != null && currentImplementation.tok != Token.NoToken ? string.Format("{0}({1},{2})", currentImplementation.tok.filename, currentImplementation.tok.line, currentImplementation.tok.col) : "<unknown location>"; Console.Out.WriteLine("Processing implementation {0} (at {1}):", currentImplementation.Name, loc); foreach (var a in axioms) { Console.Out.Write(" >>> added axiom: "); a.Expr.Emit(tokTxtWr); Console.Out.WriteLine(); } foreach (var b in after) { Console.Out.Write(" >>> added after assuming the current precondition: "); b.Emit(tokTxtWr, 0); } } } } #endregion var result = VisitImplementation(currentImplementation); currentImplementation = null; this.programInCachedSnapshot = null; return(result); }