/// <summary>
/// Merges two instances based on the stronger of both variabilities and the set union of their reaching definitions
/// </summary>
/// <param name="a">first instance</param>
/// <param name="b">second instance</param>
/// <returns>instance representing the merged information of both instances</returns>
public static VariabilityInfo MergeDefs(VariabilityInfo a, VariabilityInfo b)
{
Contract.Requires(a.Definitions != null);
Contract.Requires(b.Definitions != null);
return(new VariabilityInfo(
VariabilityOperations.Stronger(a.Variability, b.Variability),
a.Definitions.Union(b.Definitions).Distinct().ToArray()));
}
private AbstractStackState <VariabilityInfo> HandleBinBranch(ILInstruction ili, AbstractStackState <VariabilityInfo> pre)
{
VariabilityInfo a = pre[0];
VariabilityInfo b = pre[1];
var next = pre.Pop().Pop();
if (VariabilityOperations.Stronger(a.Variability, b.Variability) == EVariability.Constant)
{
next = next.UniqueSuccessor();
}
else
{
next = next.AmbiguousSuccessor();
}
return(next);
}
private AbstractStackState <VariabilityInfo> HandleCall(ILInstruction ili, AbstractStackState <VariabilityInfo> pre, bool isCalli)
{
MethodBase callee = (MethodBase)ili.Operand;
bool hasThis = callee.CallingConvention.HasFlag(CallingConventions.HasThis);
EVariability callVar = EVariability.Constant;
ParameterInfo[] args = callee.GetParameters();
MethodFacts myFacts = FactUniverse.Instance.GetFacts(Method);
MethodFacts calleeFacts = FactUniverse.Instance.GetFacts(callee);
AbstractStackState <VariabilityInfo> next = pre;
if (hasThis)
{
callVar = VariabilityOperations.Stronger(callVar, pre[0].Variability);
next = pre.Pop();
}
for (int i = 0; i < args.Length; i++)
{
callVar = VariabilityOperations.Stronger(callVar, next[0].Variability);
next = next.Pop();
}
if (!calleeFacts.IsSideEffectFree)
{
callVar = EVariability.ExternVariable;
}
if (calleeFacts.IsStaticEvaluation)
{
callVar = EVariability.Constant;
}
if (isCalli)
{
next = pre.Pop();
}
VariabilityInfo callVarI = VariabilityInfo.CreateBySingleDef(callVar, ili.Index);
next = UpdateStackState(ili, callVarI, next);
Type returnType;
if (callee.IsFunction(out returnType))
{
next = next.Push(callVarI);
}
return(next.UniqueSuccessor());
}
/// <summary>
/// Merges two instances under assumption of a single reaching definition
/// </summary>
/// <param name="a">first instance</param>
/// <param name="b">second instance</param>
/// <param name="def">the one and only reaching definition</param>
/// <returns>merged instance, based on the stronger of both variabilities</returns>
public static VariabilityInfo MergeByNewDef(VariabilityInfo a, VariabilityInfo b, int def)
{
return(CreateBySingleDef(
VariabilityOperations.Stronger(a.Variability, b.Variability),
def));
}
