/// <summary>
/// Tries to return the literal obtained from constant folding the binary expression whose literal arguments are given
/// by opnd1 and opnd2. If any of these are null, the result is null. If the binary expression cannot be constant folded
/// the result is also null.
/// </summary>
/// <param name="opnd1">null or literal corresponding to binary expression's 1st constant folded argument</param>
/// <param name="opnd2">null or literal corresponding to binary expression's 2nd constant folded argument</param>
/// <param name="binaryExpression">the original binary expression</param>
/// <returns>null, or constant folded literal</returns>
public static Literal EvalBinaryExpression(Literal opnd1, Literal opnd2, BinaryExpression binaryExpression, TypeSystem typeSystem){
if (binaryExpression == null) return null;
if (opnd1 == null) return null;
if (opnd2 == null) return null;
IConvertible ic1 = opnd1.Value as IConvertible;
IConvertible ic2 = opnd2.Value as IConvertible;
TypeCode code1 = ic1 == null ? TypeCode.Object : ic1.GetTypeCode();
TypeCode code2 = ic2 == null ? TypeCode.Object : ic2.GetTypeCode();
TypeNode type = SystemTypes.Object;
object val = null;
switch (binaryExpression.NodeType){
case NodeType.Add :
if (typeSystem != null && typeSystem.checkOverflow) goto case NodeType.Add_Ovf;
return PureEvaluator.DoAdd(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Add_Ovf :
case NodeType.Add_Ovf_Un :
return PureEvaluator.DoAddOvf(ic1, ic2, code1, code2, binaryExpression);
case NodeType.AddEventHandler :
return null;
case NodeType.And :
return PureEvaluator.DoAnd(ic1, ic2, code1, code2, binaryExpression);
case NodeType.As :
return null;
case NodeType.Box :
case NodeType.Castclass :
case NodeType.ExplicitCoercion :
type = (TypeNode)opnd2.Value;
TypeNode t = type;
EnumNode en = type as EnumNode;
if (en != null) t = en.UnderlyingType;
if (t == null || !t.IsPrimitive) return null;
if (typeSystem != null && binaryExpression.NodeType == NodeType.ExplicitCoercion){
ErrorHandler savedErrorHandler = typeSystem.ErrorHandler;
typeSystem.ErrorHandler = null;
Expression result;
try {
result = typeSystem.ExplicitLiteralCoercion(opnd1, opnd1.Type, t, null);
}
finally {
typeSystem.ErrorHandler = savedErrorHandler;
};
return result as Literal;
}
Type rt = t.GetRuntimeType();
if (rt != null)
val = Convert.ChangeType(opnd1.Value, rt, null);
else
val = opnd1.Value;
break;
case NodeType.Ceq :
case NodeType.Cgt :
case NodeType.Cgt_Un :
case NodeType.Clt :
case NodeType.Clt_Un :
return null;
case NodeType.Comma:
return opnd2;
case NodeType.Div :
case NodeType.Div_Un :
return PureEvaluator.DoDiv(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Eq :
return PureEvaluator.DoEq(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Ge :
return PureEvaluator.DoGe(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Gt :
return PureEvaluator.DoGt(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Is :
case NodeType.Isinst :
case NodeType.Ldvirtftn :
return null;
case NodeType.Le :
return PureEvaluator.DoLe(ic1, ic2, code1, code2, binaryExpression);
case NodeType.LogicalAnd :
return PureEvaluator.DoLogicalAnd(ic1, ic2, code1, code2, binaryExpression);
case NodeType.LogicalOr :
return PureEvaluator.DoLogicalOr(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Lt :
return PureEvaluator.DoLt(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Mkrefany :
return null;
case NodeType.Mul :
if (typeSystem != null && typeSystem.checkOverflow) goto case NodeType.Mul_Ovf;
return PureEvaluator.DoMul(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Mul_Ovf :
case NodeType.Mul_Ovf_Un :
return PureEvaluator.DoMulOvf(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Ne :
return PureEvaluator.DoNe(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Or :
return PureEvaluator.DoOr(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Refanyval :
return null;
case NodeType.Rem :
case NodeType.Rem_Un :
return PureEvaluator.DoRem(ic1, ic2, code1, code2, binaryExpression);
case NodeType.RemoveEventHandler :
return null;
case NodeType.Shl :
return PureEvaluator.DoLeftShift(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Shr :
case NodeType.Shr_Un :
return PureEvaluator.DoRightShift(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Sub :
if (typeSystem != null && typeSystem.checkOverflow) goto case NodeType.Sub_Ovf;
return PureEvaluator.DoSub(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Sub_Ovf :
case NodeType.Sub_Ovf_Un :
return PureEvaluator.DoSubOvf(ic1, ic2, code1, code2, binaryExpression);
case NodeType.Unbox :
case NodeType.Xor :
default:
return null;
}
return new Literal(val, type, binaryExpression.SourceContext);
}