internal static bool AreEquivalent(Instruction source, Instruction target)
{
if (source.OpCode.Code != target.OpCode.Code)
return false;
if (source.OpCode.Code == Code.Ldstr)
return true;
//Check the types in ldarg stuff. Sometimes this scheme
//could lead us to false positives. We need an analysis
//which depends on the context.
if (source.IsLoadArgument ()) {
// case where 'ldarg this' is used (p.GetSequence () would be 0)
if (!Current.HasParameters && !Target.HasParameters)
return true;
return AreEquivalent (source.GetParameter (Current), target.GetParameter (Target));
}
// The same for ldloc / stloc
if (source.IsLoadLocal () || source.IsStoreLocal ())
return AreEquivalent (source.GetVariable (Current), target.GetVariable (Target));
//WARNING: Dirty Evil Hack: this should be in the
//Pattern class
if (source.OpCode.Code == Code.Ret && source.Previous != null &&
(source.Previous.OpCode.StackBehaviourPush == StackBehaviour.Pushi ||
source.Previous.OpCode.Code == Code.Ldnull ||
source.Previous.OpCode.StackBehaviourPush == StackBehaviour.Push1))
return false;
//if (source.Operand != target.Operand)
if (source.Operand != null && target.Operand != null) {
// we're sure that target.Operand is of the same type as source.Operand (same OpCode is used)
Instruction si = (source.Operand as Instruction);
if (si != null)
return (si.Offset == ((Instruction) target.Operand).Offset);
IMetadataTokenProvider sm = (source.Operand as IMetadataTokenProvider);
if (sm != null)
return sm.Equals (target.Operand as IMetadataTokenProvider);
if (source.Operand == target.Operand)
return true;
// last chance: we do call ToString
if (source.Operand.ToString () != target.Operand.ToString ())
return false;
}
return true;
}
private static bool CheckCeqInstruction (Instruction instruction, MethodDefinition method)
{
bool problem = false;
switch (instruction.OpCode.Code) {
case Code.Conv_R_Un:
case Code.Conv_R4:
case Code.Conv_R8:
return true;
case Code.Ldc_R4:
return !CheckFloatConstants ((float) instruction.Operand);
case Code.Ldc_R8:
return !CheckDoubleConstants ((double) instruction.Operand);
case Code.Ldelem_R4:
case Code.Ldelem_R8:
return true;
case Code.Ldloc_0:
case Code.Ldloc_1:
case Code.Ldloc_2:
case Code.Ldloc_3:
case Code.Ldloc_S:
case Code.Ldloc:
case Code.Ldloca:
case Code.Ldloca_S:
return instruction.GetVariable (method).VariableType.IsFloatingPoint ();
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
case Code.Ldarg:
case Code.Ldarg_S:
case Code.Ldarga:
case Code.Ldarga_S:
ParameterDefinition parameter = instruction.GetParameter (method);
// handle 'this'
if (parameter == null)
return method.DeclaringType.IsFloatingPoint ();
return parameter.ParameterType.IsFloatingPoint ();
case Code.Call:
case Code.Callvirt:
MethodReference call = instruction.Operand as MethodReference;
return call.ReturnType.IsFloatingPoint ();
case Code.Ldfld:
case Code.Ldflda:
case Code.Ldsfld:
case Code.Ldsflda:
FieldReference field = instruction.Operand as FieldReference;
return field.FieldType.IsFloatingPoint ();
}
return problem;
}
private void CheckArgument (MethodDefinition method, Instruction ins)
{
ParameterDefinition parameter = ins.GetParameter (method);
if (parameter == null)
return;
// avoid checking parameters where a null check was already found
if (has_null_check.Get (parameter.GetSequence ()))
return;
Instruction next = ins.Next;
Code nc = next.OpCode.Code;
switch (nc) {
case Code.Box: // generics
case Code.Ldind_Ref: // load indirect reference
next = next.Next;
nc = next.OpCode.Code;
break;
}
if (null_compare.Get (nc)) {
has_null_check.Set (parameter.GetSequence ());
} else {
// compare with null (next or previous to current instruction)
// followed by a CEQ instruction
if (nc == Code.Ldnull) {
if (next.Next.OpCode.Code == Code.Ceq)
has_null_check.Set (parameter.GetSequence ());
} else if (nc == Code.Ceq) {
if (ins.Previous.OpCode.Code == Code.Ldnull)
has_null_check.Set (parameter.GetSequence ());
}
}
}
