private static void GenerateCandidateForNonNegativeGuardVariables(GPUVerifier verifier, Implementation impl, IRegion region)
{
HashSet <Variable> partitionVars = region.PartitionVariablesOfHeader();
HashSet <Variable> nonnegVars = new HashSet <Variable>();
var formals = impl.InParams.Select(x => x.Name);
var modset = GetModifiedVariables(region).Select(x => x.Name);
Regex pattern = new Regex(@"\bBV\d*_((SLE)|(SLT)|(SGE)|(SGT))\b");
foreach (var v in partitionVars)
{
var expr = verifier.varDefAnalysesRegion[impl].DefOfVariableName(v.Name);
if (!(expr is NAryExpr))
{
continue;
}
var nary = expr as NAryExpr;
if (!pattern.Match(nary.Fun.FunctionName).Success)
{
continue;
}
var visitor = new VariablesOccurringInExpressionVisitor();
visitor.Visit(nary);
nonnegVars.UnionWith(
visitor.GetVariables().Where(
x => x.Name.StartsWith("$") &&
!formals.Contains(x.Name) &&
modset.Contains(x.Name) &&
x.TypedIdent.Type.IsBv
)
);
}
foreach (var v in nonnegVars)
{
int BVWidth = v.TypedIdent.Type.BvBits;
// REVISIT: really we only want to guess for /integer/ variables.
if (BVWidth >= 8)
{
var inv = verifier.IntRep.MakeSle(verifier.Zero(BVWidth), new IdentifierExpr(v.tok, v));
verifier.AddCandidateInvariant(region, inv, "guardNonNeg");
}
}
}
private void MakeDual(List <Cmd> cs, Cmd c)
{
if (c is CallCmd)
{
CallCmd Call = c as CallCmd;
if (QKeyValue.FindBoolAttribute(Call.Proc.Attributes, "barrier_invariant"))
{
// There may be a predicate, and there must be an invariant expression and at least one instantiation
Debug.Assert(Call.Ins.Count >= (2 + (verifier.uniformityAnalyser.IsUniform(Call.callee) ? 0 : 1)));
var BIDescriptor = new UnaryBarrierInvariantDescriptor(
verifier.uniformityAnalyser.IsUniform(Call.callee) ? Expr.True : Call.Ins[0],
Expr.Neq(Call.Ins[verifier.uniformityAnalyser.IsUniform(Call.callee) ? 0 : 1],
verifier.Zero(1)),
Call.Attributes,
this, procName, verifier);
for (var i = 1 + (verifier.uniformityAnalyser.IsUniform(Call.callee) ? 0 : 1); i < Call.Ins.Count; i++)
{
BIDescriptor.AddInstantiationExpr(Call.Ins[i]);
}
BarrierInvariantDescriptors.Add(BIDescriptor);
return;
}
if (QKeyValue.FindBoolAttribute(Call.Proc.Attributes, "binary_barrier_invariant"))
{
// There may be a predicate, and there must be an invariant expression and at least one pair of
// instantiation expressions
Debug.Assert(Call.Ins.Count >= (3 + (verifier.uniformityAnalyser.IsUniform(Call.callee) ? 0 : 1)));
var BIDescriptor = new BinaryBarrierInvariantDescriptor(
verifier.uniformityAnalyser.IsUniform(Call.callee) ? Expr.True : Call.Ins[0],
Expr.Neq(Call.Ins[verifier.uniformityAnalyser.IsUniform(Call.callee) ? 0 : 1],
verifier.Zero(1)),
Call.Attributes,
this, procName, verifier);
for (var i = 1 + (verifier.uniformityAnalyser.IsUniform(Call.callee) ? 0 : 1); i < Call.Ins.Count; i += 2)
{
BIDescriptor.AddInstantiationExprPair(Call.Ins[i], Call.Ins[i + 1]);
}
BarrierInvariantDescriptors.Add(BIDescriptor);
return;
}
if (GPUVerifier.IsBarrier(Call.Proc))
{
// Assert barrier invariants
foreach (var BIDescriptor in BarrierInvariantDescriptors)
{
QKeyValue SourceLocationInfo = BIDescriptor.GetSourceLocationInfo();
cs.Add(BIDescriptor.GetAssertCmd());
var vd = new VariableDualiser(1, verifier.uniformityAnalyser, procName);
if (GPUVerifyVCGenCommandLineOptions.BarrierAccessChecks)
{
foreach (Expr AccessExpr in BIDescriptor.GetAccessedExprs())
{
var Assert = new AssertCmd(Token.NoToken, AccessExpr, MakeThreadSpecificAttributes(SourceLocationInfo, 1));
Assert.Attributes = new QKeyValue(Token.NoToken, "barrier_invariant_access_check",
new List <object> {
Expr.True
}, Assert.Attributes);
cs.Add(vd.VisitAssertCmd(Assert));
}
}
}
}
List <Expr> uniformNewIns = new List <Expr>();
List <Expr> nonUniformNewIns = new List <Expr>();
for (int i = 0; i < Call.Ins.Count; i++)
{
if (verifier.uniformityAnalyser.knowsOf(Call.callee) && verifier.uniformityAnalyser.IsUniform(Call.callee, verifier.uniformityAnalyser.GetInParameter(Call.callee, i)))
{
uniformNewIns.Add(Call.Ins[i]);
}
else if (!verifier.OnlyThread2.Contains(Call.callee))
{
nonUniformNewIns.Add(new VariableDualiser(1, verifier.uniformityAnalyser, procName).VisitExpr(Call.Ins[i]));
}
}
for (int i = 0; i < Call.Ins.Count; i++)
{
if (
!(verifier.uniformityAnalyser.knowsOf(Call.callee) && verifier.uniformityAnalyser.IsUniform(Call.callee, verifier.uniformityAnalyser.GetInParameter(Call.callee, i))) &&
!verifier.OnlyThread1.Contains(Call.callee))
{
nonUniformNewIns.Add(new VariableDualiser(2, verifier.uniformityAnalyser, procName).VisitExpr(Call.Ins[i]));
}
}
List <Expr> newIns = uniformNewIns;
newIns.AddRange(nonUniformNewIns);
List <IdentifierExpr> uniformNewOuts = new List <IdentifierExpr>();
List <IdentifierExpr> nonUniformNewOuts = new List <IdentifierExpr>();
for (int i = 0; i < Call.Outs.Count; i++)
{
if (verifier.uniformityAnalyser.knowsOf(Call.callee) && verifier.uniformityAnalyser.IsUniform(Call.callee, verifier.uniformityAnalyser.GetOutParameter(Call.callee, i)))
{
uniformNewOuts.Add(Call.Outs[i]);
}
else
{
nonUniformNewOuts.Add(new VariableDualiser(1, verifier.uniformityAnalyser, procName).VisitIdentifierExpr(Call.Outs[i].Clone() as IdentifierExpr) as IdentifierExpr);
}
}
for (int i = 0; i < Call.Outs.Count; i++)
{
if (!(verifier.uniformityAnalyser.knowsOf(Call.callee) && verifier.uniformityAnalyser.IsUniform(Call.callee, verifier.uniformityAnalyser.GetOutParameter(Call.callee, i))))
{
nonUniformNewOuts.Add(new VariableDualiser(2, verifier.uniformityAnalyser, procName).VisitIdentifierExpr(Call.Outs[i].Clone() as IdentifierExpr) as IdentifierExpr);
}
}
List <IdentifierExpr> newOuts = uniformNewOuts;
newOuts.AddRange(nonUniformNewOuts);
CallCmd NewCallCmd = new CallCmd(Call.tok, Call.callee, newIns, newOuts);
NewCallCmd.Proc = Call.Proc;
NewCallCmd.Attributes = Call.Attributes;
if (NewCallCmd.callee.StartsWith("_LOG_ATOMIC"))
{
QKeyValue curr = NewCallCmd.Attributes;
if (curr.Key.StartsWith("arg"))
{
NewCallCmd.Attributes = new QKeyValue(Token.NoToken, curr.Key, new List <object>(new object[] { Dualise(curr.Params[0] as Expr, 1) }), curr.Next);
}
for (curr = NewCallCmd.Attributes; curr.Next != null; curr = curr.Next)
{
if (curr.Next.Key.StartsWith("arg"))
{
curr.Next = new QKeyValue(Token.NoToken, curr.Next.Key, new List <object>(new object[] { Dualise(curr.Next.Params[0] as Expr, 1) }), curr.Next.Next);
}
}
}
else if (NewCallCmd.callee.StartsWith("_CHECK_ATOMIC"))
{
QKeyValue curr = NewCallCmd.Attributes;
if (curr.Key.StartsWith("arg"))
{
NewCallCmd.Attributes = new QKeyValue(Token.NoToken, curr.Key, new List <object>(new object[] { Dualise(curr.Params[0] as Expr, 2) }), curr.Next);
}
for (curr = NewCallCmd.Attributes; curr.Next != null; curr = curr.Next)
{
if (curr.Next.Key.StartsWith("arg"))
{
curr.Next = new QKeyValue(Token.NoToken, curr.Next.Key, new List <object>(new object[] { Dualise(curr.Next.Params[0] as Expr, 2) }), curr.Next.Next);
}
}
}
cs.Add(NewCallCmd);
if (GPUVerifier.IsBarrier(Call.Proc))
{
foreach (var BIDescriptor in BarrierInvariantDescriptors)
{
foreach (var Instantiation in BIDescriptor.GetInstantiationCmds())
{
cs.Add(Instantiation);
}
}
BarrierInvariantDescriptors.Clear();
}
}
else if (c is AssignCmd)
{
AssignCmd assign = c as AssignCmd;
var vd1 = new VariableDualiser(1, verifier.uniformityAnalyser, procName);
var vd2 = new VariableDualiser(2, verifier.uniformityAnalyser, procName);
List <AssignLhs> lhss1 = new List <AssignLhs>();
List <AssignLhs> lhss2 = new List <AssignLhs>();
List <Expr> rhss1 = new List <Expr>();
List <Expr> rhss2 = new List <Expr>();
foreach (var pair in assign.Lhss.Zip(assign.Rhss))
{
if (pair.Item1 is SimpleAssignLhs &&
verifier.uniformityAnalyser.IsUniform(procName,
(pair.Item1 as SimpleAssignLhs).AssignedVariable.Name))
{
lhss1.Add(pair.Item1);
rhss1.Add(pair.Item2);
}
else
{
lhss1.Add(vd1.Visit(pair.Item1.Clone() as AssignLhs) as AssignLhs);
lhss2.Add(vd2.Visit(pair.Item1.Clone() as AssignLhs) as AssignLhs);
rhss1.Add(vd1.VisitExpr(pair.Item2.Clone() as Expr));
rhss2.Add(vd2.VisitExpr(pair.Item2.Clone() as Expr));
}
}
Debug.Assert(lhss1.Count > 0);
cs.Add(new AssignCmd(Token.NoToken, lhss1, rhss1));
if (lhss2.Count > 0)
{
cs.Add(new AssignCmd(Token.NoToken, lhss2, rhss2));
}
}
else if (c is HavocCmd)
{
HavocCmd havoc = c as HavocCmd;
Debug.Assert(havoc.Vars.Count() == 1);
HavocCmd newHavoc;
newHavoc = new HavocCmd(havoc.tok, new List <IdentifierExpr>(new IdentifierExpr[] {
(IdentifierExpr)(new VariableDualiser(1, verifier.uniformityAnalyser, procName).VisitIdentifierExpr(havoc.Vars[0].Clone() as IdentifierExpr)),
(IdentifierExpr)(new VariableDualiser(2, verifier.uniformityAnalyser, procName).VisitIdentifierExpr(havoc.Vars[0].Clone() as IdentifierExpr))
}));
cs.Add(newHavoc);
}
else if (c is AssertCmd)
{
AssertCmd a = c as AssertCmd;
if (QKeyValue.FindBoolAttribute(a.Attributes, "sourceloc") ||
QKeyValue.FindBoolAttribute(a.Attributes, "block_sourceloc") ||
QKeyValue.FindBoolAttribute(a.Attributes, "array_bounds"))
{
// This is just a location marker, so we do not dualise it
cs.Add(new AssertCmd(Token.NoToken, new VariableDualiser(1, verifier.uniformityAnalyser, procName).VisitExpr(a.Expr.Clone() as Expr),
(QKeyValue)a.Attributes.Clone()));
}
else
{
var isUniform = verifier.uniformityAnalyser.IsUniform(procName, a.Expr);
cs.Add(MakeThreadSpecificAssert(a, 1));
if (!GPUVerifyVCGenCommandLineOptions.AsymmetricAsserts && !ContainsAsymmetricExpression(a.Expr) && !isUniform)
{
cs.Add(MakeThreadSpecificAssert(a, 2));
}
}
}
else if (c is AssumeCmd)
{
AssumeCmd ass = c as AssumeCmd;
if (QKeyValue.FindStringAttribute(ass.Attributes, "captureState") != null)
{
cs.Add(c);
}
else if (QKeyValue.FindBoolAttribute(ass.Attributes, "backedge"))
{
AssumeCmd newAss = new AssumeCmd(c.tok, Expr.Or(new VariableDualiser(1, verifier.uniformityAnalyser, procName).VisitExpr(ass.Expr.Clone() as Expr),
new VariableDualiser(2, verifier.uniformityAnalyser, procName).VisitExpr(ass.Expr.Clone() as Expr)));
newAss.Attributes = ass.Attributes;
cs.Add(newAss);
}
else if (QKeyValue.FindBoolAttribute(ass.Attributes, "atomic_refinement"))
{
// Generate the following:
// havoc v$1, v$2;
// assume !_USED[offset$1][v$1];
// _USED[offset$1][v$1] := true;
// assume !_USED[offset$2][v$2];
// _USED[offset$2][v$2] := true;
Expr variable = QKeyValue.FindExprAttribute(ass.Attributes, "variable");
Expr offset = QKeyValue.FindExprAttribute(ass.Attributes, "offset");
List <Expr> offsets = (new int[] { 1, 2 }).Select(x => new VariableDualiser(x, verifier.uniformityAnalyser, procName).VisitExpr(offset.Clone() as Expr)).ToList();
List <Expr> vars = (new int[] { 1, 2 }).Select(x => new VariableDualiser(x, verifier.uniformityAnalyser, procName).VisitExpr(variable.Clone() as Expr)).ToList();
IdentifierExpr arrayref = new IdentifierExpr(Token.NoToken, verifier.FindOrCreateUsedMap(QKeyValue.FindStringAttribute(ass.Attributes, "arrayref"), vars[0].Type));
foreach (int i in (new int[] { 0, 1 }))
{
AssumeCmd newAss = new AssumeCmd(c.tok, Expr.Not(new NAryExpr(Token.NoToken, new MapSelect(Token.NoToken, 1),
new List <Expr> {
new NAryExpr(Token.NoToken, new MapSelect(Token.NoToken, 1),
new List <Expr> {
arrayref, offsets[i]
}),
vars[i]
})));
cs.Add(newAss);
var lhs = new MapAssignLhs(Token.NoToken, new MapAssignLhs(Token.NoToken, new SimpleAssignLhs(Token.NoToken, arrayref),
new List <Expr> {
offsets[i]
}), new List <Expr> {
vars[i]
});
AssignCmd assign = new AssignCmd(c.tok,
new List <AssignLhs> {
lhs
},
new List <Expr> {
Expr.True
});
cs.Add(assign);
}
}
else
{
var isUniform = verifier.uniformityAnalyser.IsUniform(procName, ass.Expr);
AssumeCmd newAss = new AssumeCmd(c.tok, new VariableDualiser(1, verifier.uniformityAnalyser, procName).VisitExpr(ass.Expr.Clone() as Expr));
if (!ContainsAsymmetricExpression(ass.Expr) && !isUniform)
{
newAss.Expr = Expr.And(newAss.Expr, new VariableDualiser(2, verifier.uniformityAnalyser, procName).VisitExpr(ass.Expr.Clone() as Expr));
}
newAss.Attributes = ass.Attributes;
cs.Add(newAss);
}
}
else
{
Debug.Assert(false);
}
}
public static StrideConstraint Bottom(GPUVerifier verifier, Expr e)
{
return(new ModStrideConstraint(verifier.IntRep.GetLiteral(1, e.Type is BvType ? e.Type.BvBits : verifier.size_t_bits),
verifier.Zero(e.Type is BvType ? e.Type.BvBits : verifier.size_t_bits)));
}