| public static GetDefaultValue ( ConstValKind kind ) : CONSTVAL | ||
| kind | ConstValKind | |
| return | CONSTVAL | |
private bool bindImplicitConversionToEnum(AggregateType aggTypeSrc)
{
// The spec states:
// *****************
// 13.1.3 Implicit enumeration conversions
//
// An implicit enumeration conversion permits the decimal-integer-literal 0 to be converted to any
// enum-type.
// *****************
// However, we actually allow any constant zero, not just the integer literal zero, to be converted
// to enum. The reason for this is for backwards compatibility with a premature optimization
// that used to be in the binding layer. We would optimize away expressions such as 0 | blah to be
// just 0, but not erase the "is literal" bit. This meant that expression such as 0 | 0 | E.X
// would succeed rather than correctly producing an error pointing out that 0 | 0 is not a literal
// zero and therefore does not convert to any enum.
//
// We have removed the premature optimization but want old code to continue to compile. Rather than
// try to emulate the somewhat complex behaviour of the previous optimizer, it is easier to simply
// say that any compile time constant zero is convertible to any enum. This means unfortunately
// expressions such as (7-7) * 12 are convertible to enum, but frankly, that's better than having
// some terribly complex rule about what constitutes a legal zero and what doesn't.
// Note: Don't use GetConst here since the conversion only applies to bona-fide compile time constants.
if (
aggTypeSrc.getAggregate().GetPredefType() != PredefinedType.PT_BOOL &&
exprSrc != null &&
exprSrc.isZero() &&
exprSrc.type.isNumericType() &&
/*(exprSrc.flags & EXF_LITERALCONST) &&*/
0 == (flags & CONVERTTYPE.STANDARD))
{
// NOTE: This allows conversions from uint, long, ulong, float, double, and hexadecimal int
// NOTE: This is for backwards compatibility with Everett
// REVIEW: : This is another place where we lose EXPR fidelity. We shouldn't fold this
// into a constant here - we should move this to a later pass.
if (needsExprDest)
{
exprDest = GetExprFactory().CreateConstant(typeDest, ConstValFactory.GetDefaultValue(typeDest.constValKind()));
}
return(true);
}
return(false);
}
private EXPR CreateZeroInit(EXPRTYPEORNAMESPACE pTypeExpr, EXPR pOptionalOriginalConstructorCall, bool isConstructor)
{
Debug.Assert(pTypeExpr != null);
CType pType = pTypeExpr.TypeOrNamespace.AsType();
bool bIsError = false;
if (pType.isEnumType())
{
// For enum types, we create a constant that has the default value
// as an object pointer.
ConstValFactory factory = new ConstValFactory();
EXPRCONSTANT expr = CreateConstant(pType, factory.Create(Activator.CreateInstance(pType.AssociatedSystemType)));
return(expr);
}
switch (pType.fundType())
{
default:
bIsError = true;
break;
case FUNDTYPE.FT_PTR:
{
CType nullType = GetTypes().GetNullType();
// UNDONE: I think this if is always false ...
if (nullType.fundType() == pType.fundType())
{
// Create a constant here.
EXPRCONSTANT expr = CreateConstant(pType, ConstValFactory.GetDefaultValue(ConstValKind.IntPtr));
return(expr);
}
// Just allocate a new node and fill it in.
EXPRCAST cast = CreateCast(0, pTypeExpr, CreateNull()); // UNDONE: should pTree be passed in here?
return(cast);
}
case FUNDTYPE.FT_REF:
case FUNDTYPE.FT_I1:
case FUNDTYPE.FT_U1:
case FUNDTYPE.FT_I2:
case FUNDTYPE.FT_U2:
case FUNDTYPE.FT_I4:
case FUNDTYPE.FT_U4:
case FUNDTYPE.FT_I8:
case FUNDTYPE.FT_U8:
case FUNDTYPE.FT_R4:
case FUNDTYPE.FT_R8:
{
EXPRCONSTANT expr = CreateConstant(pType, ConstValFactory.GetDefaultValue(pType.constValKind()));
EXPRCONSTANT exprInOriginal = CreateConstant(pType, ConstValFactory.GetDefaultValue(pType.constValKind()));
exprInOriginal.SetOptionalConstructorCall(pOptionalOriginalConstructorCall);
return(expr);
// UNDONE: Check other bogus casts
}
case FUNDTYPE.FT_STRUCT:
if (pType.isPredefType(PredefinedType.PT_DECIMAL))
{
EXPRCONSTANT expr = CreateConstant(pType, ConstValFactory.GetDefaultValue(pType.constValKind()));
EXPRCONSTANT exprOriginal = CreateConstant(pType, ConstValFactory.GetDefaultValue(pType.constValKind()));
exprOriginal.SetOptionalConstructorCall(pOptionalOriginalConstructorCall);
return(expr);
}
break;
case FUNDTYPE.FT_VAR:
break;
}
EXPRZEROINIT rval = new EXPRZEROINIT();
rval.kind = ExpressionKind.EK_ZEROINIT;
rval.type = pType;
rval.flags = 0;
rval.OptionalConstructorCall = pOptionalOriginalConstructorCall;
rval.IsConstructor = isConstructor;
if (bIsError)
{
rval.SetError();
}
Debug.Assert(rval != null);
return(rval);
}