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;
}
static bool OriginsMatch (MethodDefinition method, Instruction lhs, Instruction rhs)
{
bool match = false;
object operand1 = lhs.GetOperand (method);
object operand2 = rhs.GetOperand (method);
if (lhs.OpCode.Code == rhs.OpCode.Code) {
if (lhs.IsLoadArgument ())
match = operand1.Equals (operand2);
else if (lhs.IsLoadElement ())
match = LoadElementMatch (method, lhs, rhs);
else if (lhs.IsLoadIndirect ())
match = LoadIndirectMatch (method, lhs, rhs);
else if (lhs.IsLoadLocal ())
match = LocalsMatch (operand1, operand2);
} else if (lhs.IsStoreLocal () && rhs.IsLoadLocal ())
match = LocalsMatch (operand1, operand2);
else if (lhs.IsLoadLocal () && rhs.IsStoreLocal ())
match = LocalsMatch (operand1, operand2);
return match;
}
