private IEnumerable <Instruction> Sinks(BasicBlock <Instruction> block, Instruction instruction, CFG cdfg)
{
switch (instruction.Operation.OperationCode)
{
case OperationCode.Call:
case OperationCode.Callvirt:
{
var methodRef = instruction.Operation.Value as IMethodReference;
if (methodRef != null)
{
if (IsDisposeMethod(methodRef))
{
var constraint = block.CallConstraint(instruction);
if (methodRef.ContainingType.IsValueType || constraint != null && (constraint.IsValueType || constraint is IGenericParameter))
{
// passing the address, figure out what local
var loc = cdfg.LocalOrParameter(instruction.Operand1);
var toDispose = instruction[loc];
yield return(toDispose);
}
else
{
yield return(instruction.Operand1); // consumes the "this" parameter
}
}
var args = instruction.Operand2 as Instruction[];
if (args != null)
{
foreach (var p in methodRef.Parameters)
{
if (p.IsByReference && IsDisposableType(p.Type) && p.Index < args.Length || PassingObligationTo(methodRef, p))
{
var arg = args[p.Index];
if (arg != null)
{
yield return(arg);
}
}
}
}
}
break;
}
case OperationCode.Stfld:
// consider fields escaping
yield return(instruction.Operand2 as Instruction);
break;
case OperationCode.Stsfld:
// consider fields escaping
yield return(instruction.Operand1);
break;
case OperationCode.Ret:
if (instruction.Operand1 != null && IsDisposableType(this.currentMethod.Type))
{
yield return(instruction.Operand1); // consumes the returned value
}
// by ref parameters are also sinks
foreach (var p in this.currentMethod.Parameters)
{
Instruction finalParameterValue;
if ((p.IsByReference || p.IsOut) && IsDisposableType(p.Type) && instruction.PostParamDefs != null && instruction.PostParamDefs.TryGetValue(p, out finalParameterValue))
{
yield return(finalParameterValue);
}
}
break;
}
}
