private static void EmitNullableToNullableConversion(this ILGenerator ilGenerator, Type typeFrom, Type typeTo, bool isChecked)
{
Label labIfNull = default(Label);
Label labEnd = default(Label);
LocalBuilder locFrom = null;
LocalBuilder locTo = null;
locFrom = ilGenerator.DeclareLocal(typeFrom);
ilGenerator.Emit(OpCodes.Stloc, locFrom);
locTo = ilGenerator.DeclareLocal(typeTo);
// test for null
ilGenerator.Emit(OpCodes.Ldloca, locFrom);
ilGenerator.EmitHasValue(typeFrom);
labIfNull = ilGenerator.DefineLabel();
ilGenerator.Emit(OpCodes.Brfalse_S, labIfNull);
ilGenerator.Emit(OpCodes.Ldloca, locFrom);
ilGenerator.EmitGetValueOrDefault(typeFrom);
Type nnTypeFrom = TypeInfoUtils.GetNonNullableType(typeFrom);
Type nnTypeTo = TypeInfoUtils.GetNonNullableType(typeTo);
ilGenerator.EmitConvertToType(nnTypeFrom, nnTypeTo, isChecked);
// construct result type
ConstructorInfo ci = typeTo.GetConstructor(new Type[] { nnTypeTo });
ilGenerator.Emit(OpCodes.Newobj, ci);
ilGenerator.Emit(OpCodes.Stloc, locTo);
labEnd = ilGenerator.DefineLabel();
ilGenerator.Emit(OpCodes.Br_S, labEnd);
// if null then create a default one
ilGenerator.MarkLabel(labIfNull);
ilGenerator.Emit(OpCodes.Ldloca, locTo);
ilGenerator.Emit(OpCodes.Initobj, typeTo);
ilGenerator.MarkLabel(labEnd);
ilGenerator.Emit(OpCodes.Ldloc, locTo);
}
public static void EmitConvertToType(this ILGenerator ilGenerator, Type typeFrom, Type typeTo, bool isChecked = true)
{
if (ilGenerator == null)
{
throw new ArgumentNullException(nameof(ilGenerator));
}
if (typeFrom == null)
{
throw new ArgumentNullException(nameof(typeFrom));
}
if (typeTo == null)
{
throw new ArgumentNullException(nameof(typeTo));
}
var nnExprType = typeFrom.Unwrap();
var nnType = typeTo.Unwrap();
if (nnType == nnExprType || nnType.IsEquivalentTo(nnExprType))
{
return;
}
if (typeFrom.IsInterface || // interface cast
typeTo.IsInterface ||
typeFrom == typeof(object) || // boxing cast
typeTo == typeof(object) ||
typeFrom == typeof(Enum) ||
typeFrom == typeof(ValueType) ||
TypeInfoUtils.IsLegalExplicitVariantDelegateConversion(typeFrom, typeTo))
{
ilGenerator.EmitCastToType(typeFrom, typeTo);
}
else if (typeFrom.IsNullableType() || typeTo.IsNullableType())
{
ilGenerator.EmitNullableConversion(typeFrom, typeTo, isChecked);
}
else if (!(typeFrom.IsConvertible() && typeTo.IsConvertible()) // primitive runtime conversion
&&
(nnExprType.GetTypeInfo().IsAssignableFrom(nnType) || // down cast
nnType.GetTypeInfo().IsAssignableFrom(nnExprType))) // up cast
{
ilGenerator.EmitCastToType(typeFrom, typeTo);
}
else if (typeFrom.IsArray && typeTo.IsArray)
{
// See DevDiv Bugs #94657.
ilGenerator.EmitCastToType(typeFrom, typeTo);
}
else
{
ilGenerator.EmitNumericConversion(typeFrom, typeTo, isChecked);
}
}
private static void EmitNullableToNonNullableStructConversion(this ILGenerator ilGenerator, Type typeFrom, Type typeTo, bool isChecked)
{
LocalBuilder locFrom = null;
locFrom = ilGenerator.DeclareLocal(typeFrom);
ilGenerator.Emit(OpCodes.Stloc, locFrom);
ilGenerator.Emit(OpCodes.Ldloca, locFrom);
ilGenerator.EmitGetValue(typeFrom);
Type nnTypeFrom = TypeInfoUtils.GetNonNullableType(typeFrom);
ilGenerator.EmitConvertToType(nnTypeFrom, typeTo, isChecked);
}
internal static bool HasReferenceConversion(Type source, Type dest)
{
// void -> void conversion is handled elsewhere
// (it's an identity conversion)
// All other void conversions are disallowed.
if (source == typeof(void) || dest == typeof(void))
{
return(false);
}
var nnSourceType = TypeInfoUtils.GetNonNullableType(source).GetTypeInfo();
var nnDestType = TypeInfoUtils.GetNonNullableType(dest).GetTypeInfo();
// Down conversion
if (nnSourceType.IsAssignableFrom(nnDestType))
{
return(true);
}
// Up conversion
if (nnDestType.IsAssignableFrom(nnSourceType))
{
return(true);
}
// Interface conversion
if (source.IsInterface || dest.IsInterface)
{
return(true);
}
// Variant delegate conversion
if (IsLegalExplicitVariantDelegateConversion(source, dest))
{
return(true);
}
// Object conversion
if (source == typeof(object) || dest == typeof(object))
{
return(true);
}
return(false);
}
private static void EmitNumericConversion(this ILGenerator ilGenerator, Type typeFrom, Type typeTo, bool isChecked)
{
var isFromUnsigned = TypeInfoUtils.IsUnsigned(typeFrom);
var isFromFloatingPoint = TypeInfoUtils.IsFloatingPoint(typeFrom);
if (typeTo == typeof(float))
{
if (isFromUnsigned)
{
ilGenerator.Emit(OpCodes.Conv_R_Un);
}
ilGenerator.Emit(OpCodes.Conv_R4);
}
else if (typeTo == typeof(double))
{
if (isFromUnsigned)
{
ilGenerator.Emit(OpCodes.Conv_R_Un);
}
ilGenerator.Emit(OpCodes.Conv_R8);
}
else
{
TypeCode tc = typeTo.GetTypeCode();
if (isChecked)
{
// Overflow checking needs to know if the source value on the IL stack is unsigned or not.
if (isFromUnsigned)
{
switch (tc)
{
case TypeCode.SByte:
ilGenerator.Emit(OpCodes.Conv_Ovf_I1_Un);
break;
case TypeCode.Int16:
ilGenerator.Emit(OpCodes.Conv_Ovf_I2_Un);
break;
case TypeCode.Int32:
ilGenerator.Emit(OpCodes.Conv_Ovf_I4_Un);
break;
case TypeCode.Int64:
ilGenerator.Emit(OpCodes.Conv_Ovf_I8_Un);
break;
case TypeCode.Byte:
ilGenerator.Emit(OpCodes.Conv_Ovf_U1_Un);
break;
case TypeCode.UInt16:
case TypeCode.Char:
ilGenerator.Emit(OpCodes.Conv_Ovf_U2_Un);
break;
case TypeCode.UInt32:
ilGenerator.Emit(OpCodes.Conv_Ovf_U4_Un);
break;
case TypeCode.UInt64:
ilGenerator.Emit(OpCodes.Conv_Ovf_U8_Un);
break;
default:
throw new InvalidCastException();
}
}
else
{
switch (tc)
{
case TypeCode.SByte:
ilGenerator.Emit(OpCodes.Conv_Ovf_I1);
break;
case TypeCode.Int16:
ilGenerator.Emit(OpCodes.Conv_Ovf_I2);
break;
case TypeCode.Int32:
ilGenerator.Emit(OpCodes.Conv_Ovf_I4);
break;
case TypeCode.Int64:
ilGenerator.Emit(OpCodes.Conv_Ovf_I8);
break;
case TypeCode.Byte:
ilGenerator.Emit(OpCodes.Conv_Ovf_U1);
break;
case TypeCode.UInt16:
case TypeCode.Char:
ilGenerator.Emit(OpCodes.Conv_Ovf_U2);
break;
case TypeCode.UInt32:
ilGenerator.Emit(OpCodes.Conv_Ovf_U4);
break;
case TypeCode.UInt64:
ilGenerator.Emit(OpCodes.Conv_Ovf_U8);
break;
default:
throw new InvalidCastException();
}
}
}
else
{
switch (tc)
{
case TypeCode.SByte:
ilGenerator.Emit(OpCodes.Conv_I1);
break;
case TypeCode.Byte:
ilGenerator.Emit(OpCodes.Conv_U1);
break;
case TypeCode.Int16:
ilGenerator.Emit(OpCodes.Conv_I2);
break;
case TypeCode.UInt16:
case TypeCode.Char:
ilGenerator.Emit(OpCodes.Conv_U2);
break;
case TypeCode.Int32:
ilGenerator.Emit(OpCodes.Conv_I4);
break;
case TypeCode.UInt32:
ilGenerator.Emit(OpCodes.Conv_U4);
break;
case TypeCode.Int64:
if (isFromUnsigned)
{
ilGenerator.Emit(OpCodes.Conv_U8);
}
else
{
ilGenerator.Emit(OpCodes.Conv_I8);
}
break;
case TypeCode.UInt64:
if (isFromUnsigned || isFromFloatingPoint)
{
ilGenerator.Emit(OpCodes.Conv_U8);
}
else
{
ilGenerator.Emit(OpCodes.Conv_I8);
}
break;
default:
throw new InvalidCastException();
}
}
}
}
