private void TryElimination(IEnumerable <Variable> extraDefinedVariables)
{
bool Defined(Variable v) => varToExpr.ContainsKey(v) || extraDefinedVariables.Contains(v);
bool changed;
do
{
changed = false;
var remainingAssignments = new List <Assignment>();
foreach (var assignment in assignments)
{
if (!Defined(assignment.Var) &&
VariableCollector.Collect(assignment.Expr).
Intersect(AllIntroducedVariables).All(Defined))
{
varToExpr[assignment.Var] = SubstitutionHelper.Apply(varToExpr, assignment.Expr);
changed = true;
}
else
{
remainingAssignments.Add(assignment);
}
}
Substitution sub = Substituter.SubstitutionFromHashtable(varToExpr);
foreach (var assignment in remainingAssignments)
{
assignment.Expr = Substituter.Apply(sub, assignment.Expr);
}
assignments = remainingAssignments;
assumes = SubstitutionHelper.Apply(sub, assumes).ToList();
} while (changed);
}
private static void SubstituteBackwardAssignments(AtomicAction action)
{
foreach (Block block in action.impl.Blocks)
{
List <Cmd> cmds = new List <Cmd>();
foreach (Cmd cmd in block.cmds)
{
if (cmd is AssignCmd _assignCmd &&
QKeyValue.FindBoolAttribute(_assignCmd.Attributes, CivlAttributes.BACKWARD))
{
AssignCmd assignCmd = _assignCmd.AsSimpleAssignCmd;
var lhss = assignCmd.Lhss;
var rhss = assignCmd.Rhss;
var rhssVars = rhss.SelectMany(x => VariableCollector.Collect(x));
var lhssVars = lhss.SelectMany(x => VariableCollector.Collect(x));
if (rhssVars.Intersect(lhssVars).Any())
{
// TODO
throw new NotImplementedException("Substitution of backward assignment where lhs appears on rhs");
}
else
{
List <Expr> assumeExprs = new List <Expr>();
for (int k = 0; k < lhss.Count; k++)
{
assumeExprs.Add(Expr.Eq(lhss[k].AsExpr, rhss[k]));
}
cmds.Add(new AssumeCmd(Token.NoToken, Expr.And(assumeExprs)));
cmds.Add(new HavocCmd(Token.NoToken, lhss.Select(x => x.DeepAssignedIdentifier).ToList()));
}
}
public AtomicAction(Procedure proc, Implementation impl, MoverType moverType, LayerRange layerRange)
{
this.proc = proc;
this.impl = impl;
this.moverType = moverType;
this.layerRange = layerRange;
CivlUtil.AddInlineAttribute(proc);
CivlUtil.AddInlineAttribute(impl);
// The gate of an atomic action is represented as asserts at the beginning of the procedure body.
this.gate = impl.Blocks[0].cmds.TakeWhile((c, i) => c is AssertCmd).Cast <AssertCmd>().ToList();
impl.Blocks[0].cmds.RemoveRange(0, gate.Count);
gateUsedGlobalVars = new HashSet <Variable>(VariableCollector.Collect(gate).Where(x => x is GlobalVariable));
actionUsedGlobalVars = new HashSet <Variable>(VariableCollector.Collect(impl).Where(x => x is GlobalVariable));
modifiedGlobalVars = new HashSet <Variable>(AssignedVariables().Where(x => x is GlobalVariable));
// We usually declare the Boogie procedure and implementation of an atomic action together.
// Since Boogie only stores the supplied attributes (in particular linearity) in the procedure parameters,
// we copy them into the implementation parameters here.
for (int i = 0; i < proc.InParams.Count; i++)
{
impl.InParams[i].Attributes = proc.InParams[i].Attributes;
}
for (int i = 0; i < proc.OutParams.Count; i++)
{
impl.OutParams[i].Attributes = proc.OutParams[i].Attributes;
}
AtomicActionDuplicator.SetupCopy(this, ref firstGate, ref firstImpl, "first_");
AtomicActionDuplicator.SetupCopy(this, ref secondGate, ref secondImpl, "second_");
DeclareTriggerFunctions();
}
public override Expr VisitExpr(Expr node)
{
if (node is NAryExpr nary &&
nary.Fun is BinaryOperator op &&
op.Op == BinaryOperator.Opcode.Eq &&
VariableCollector.Collect(node).Contains(choice))
{
return(Expr.True);
}
return(base.VisitExpr(node));
}
private bool TryElimination(IEnumerable <Variable> extraDefinedVariables)
{
bool changed = false;
var remainingCmds = new List <Cmd>();
foreach (var cmd in newCmds)
{
if (cmd is AssignCmd assignCmd)
{
var lhss = new List <AssignLhs>();
var rhss = new List <Expr>();
for (int k = 0; k < assignCmd.Lhss.Count; k++)
{
var lhs = assignCmd.Lhss[k];
var rhs = assignCmd.Rhss[k];
Variable assignedVar = lhs.DeepAssignedVariable;
var allDefinedVars = varToExpr.Keys.Union(extraDefinedVariables);
if (!allDefinedVars.Contains(assignedVar) &&
!VariableCollector.Collect(rhs).Intersect(AllIntroducedVariables).
Except(allDefinedVars).Any())
{
varToExpr[assignedVar] = rhs;
changed = true;
}
else
{
lhss.Add(lhs);
rhss.Add(rhs);
}
}
if (lhss.Any())
{
remainingCmds.Add(new AssignCmd(cmd.tok, lhss, rhss, assignCmd.Attributes));
}
}
else if (cmd is AssumeCmd)
{
remainingCmds.Add(cmd);
}
}
Substitution sub = Substituter.SubstitutionFromHashtable(varToExpr);
newCmds = remainingCmds.Select(cmd => ApplyOnRhss(sub, cmd)).ToList();
return(changed);
}
private void PendingPropagate(HashSet <Variable> allExistsVars, Dictionary <Variable, Expr> existsSubstitutionMap, Variable eVar, Expr eVarSubstExpr, Dictionary <Variable, Expr> pendingMap)
{
var usedExistsVars = VariableCollector.Collect(eVarSubstExpr).Intersect(allExistsVars);
if (usedExistsVars.Count() == 0)
{
existsSubstitutionMap[eVar] = eVarSubstExpr;
}
else if (usedExistsVars.Except(existsSubstitutionMap.Keys).Count() == 0)
{
Substitution subst = Substituter.SubstitutionFromHashtable(existsSubstitutionMap);
existsSubstitutionMap[eVar] = Substituter.Apply(subst, eVarSubstExpr);
}
else
{
pendingMap[eVar] = eVarSubstExpr;
}
}
private Expr CalculatePathCondition(PathInfo path)
{
HashSet <Variable> allExistsVars = new HashSet <Variable>(firstExistsVars.Union(secondExistsVars));
HashSet <Variable> usedExistsVars = new HashSet <Variable>();
Dictionary <Variable, Expr> existsSubstitutionMap = new Dictionary <Variable, Expr>();
List <Expr> inferredSelectEqualities = new List <Expr>();
foreach (Variable v in path.varToExpr.Keys.Except(postExistVars))
{
var expr = path.varToExpr[v];
usedExistsVars.UnionWith(VariableCollector.Collect(expr).Intersect(allExistsVars));
IdentifierExpr ie = expr as IdentifierExpr;
if (ie != null && IsExistsVar(ie.Decl) && !existsSubstitutionMap.ContainsKey(ie.Decl))
{
existsSubstitutionMap[ie.Decl] = Expr.Ident(v);
}
else if (IsMapStoreExpr(expr))
{
inferredSelectEqualities.Add(GenerateEqualityWithSelect(expr as NAryExpr, Expr.Ident(v)));
}
}
foreach (Expr expr in path.pathExprs)
{
usedExistsVars.UnionWith(VariableCollector.Collect(expr).Intersect(allExistsVars));
}
InferSubstitution(allExistsVars, existsSubstitutionMap, path.pathExprs, inferredSelectEqualities);
List <Expr> triggerExprs = new List <Expr>();
List <Variable> quantifiedVars = new List <Variable>();
foreach (var v in usedExistsVars.Except(existsSubstitutionMap.Keys))
{
var triggerFun = TriggerFunction(v); // this call populates existsVars[v]
var quantifiedVar = existsVars[v];
triggerExprs.Add(
new NAryExpr(Token.NoToken,
new FunctionCall(triggerFun),
new Expr[] { Expr.Ident(quantifiedVar) }));
quantifiedVars.Add(quantifiedVar);
existsSubstitutionMap[v] = Expr.Ident(quantifiedVar);
}
Substitution subst = Substituter.SubstitutionFromHashtable(existsSubstitutionMap);
List <Expr> returnExprs = new List <Expr>();
foreach (Variable v in path.varToExpr.Keys.Except(postExistVars))
{
Expr withOldExpr = MyDuplicator.Duplicate(path.varToExpr[v]);
var substExpr = Expr.Eq(Expr.Ident(v), Substituter.Apply(subst, withOldExpr));
substExpr.Type = Type.Bool;
returnExprs.Add(substExpr);
}
foreach (Expr x in path.pathExprs)
{
var withOldExpr = MyDuplicator.Duplicate(x);
returnExprs.Add(Substituter.Apply(subst, withOldExpr));
}
var returnExpr = Expr.And(returnExprs);
if (quantifiedVars.Count > 0)
{
if (first == null)
{
returnExpr = new ExistsExpr(Token.NoToken, quantifiedVars, returnExpr);
}
else
{
returnExpr = new ExistsExpr(Token.NoToken,
quantifiedVars,
new Trigger(Token.NoToken, true, triggerExprs),
returnExpr);
}
}
return(returnExpr);
}
