void EmitBitwiseBoolean (EmitContext ec)
{
Label load_left = ec.DefineLabel ();
Label load_right = ec.DefineLabel ();
Label end_label = ec.DefineLabel ();
// null & value, null | value
if (left_unwrap == null) {
left_unwrap = right_unwrap;
right_unwrap = null;
right = left;
}
left_unwrap.Emit (ec);
ec.Emit (OpCodes.Brtrue, load_right);
// value & null, value | null
if (right_unwrap != null) {
right_unwrap.Emit (ec);
ec.Emit (OpCodes.Brtrue_S, load_left);
}
left_unwrap.EmitCheck (ec);
ec.Emit (OpCodes.Brfalse_S, load_right);
// load left
ec.MarkLabel (load_left);
if (Oper == Operator.BitwiseAnd) {
left_unwrap.Load (ec);
} else {
if (right_unwrap == null) {
right.Emit (ec);
if (right is EmptyConstantCast || right is EmptyCast)
ec.Emit (OpCodes.Newobj, NullableInfo.GetConstructor (type));
} else {
right_unwrap.Load (ec);
right_unwrap = left_unwrap;
}
}
ec.Emit (OpCodes.Br_S, end_label);
// load right
ec.MarkLabel (load_right);
if (right_unwrap == null) {
if (Oper == Operator.BitwiseAnd) {
right.Emit (ec);
if (right is EmptyConstantCast || right is EmptyCast)
ec.Emit (OpCodes.Newobj, NullableInfo.GetConstructor (type));
} else {
left_unwrap.Load (ec);
}
} else {
right_unwrap.Load (ec);
}
ec.MarkLabel (end_label);
}
protected override Expression DoResolve (ResolveContext ec)
{
unwrap = Unwrap.Create (Expr, false);
if (unwrap == null)
return null;
Expression res = base.ResolveOperator (ec, unwrap);
if (res != this) {
if (user_operator == null)
return res;
} else {
res = Expr = LiftExpression (ec, Expr);
}
if (res == null)
return null;
eclass = ExprClass.Value;
type = res.Type;
return this;
}
protected override Expression DoResolve (ResolveContext ec)
{
if ((Oper & Operator.LogicalMask) != 0) {
Error_OperatorCannotBeApplied (ec, left, right);
return null;
}
bool use_default_call = (Oper & (Operator.BitwiseMask | Operator.EqualityMask)) != 0;
left_orig = left;
if (left.Type.IsNullableType) {
left = left_unwrap = Unwrap.Create (left, use_default_call);
if (left == null)
return null;
}
right_orig = right;
if (right.Type.IsNullableType) {
right = right_unwrap = Unwrap.Create (right, use_default_call);
if (right == null)
return null;
}
//
// Some details are in 6.4.2, 7.2.7
// Arguments can be lifted for equal operators when the return type is bool and both
// arguments are of same type
//
if (left_orig is NullLiteral) {
left = right;
state |= State.LeftNullLifted;
type = ec.BuiltinTypes.Bool;
}
if (right_orig.IsNull) {
if ((Oper & Operator.ShiftMask) != 0)
right = new EmptyExpression (ec.BuiltinTypes.Int);
else
right = left;
state |= State.RightNullLifted;
type = ec.BuiltinTypes.Bool;
}
eclass = ExprClass.Value;
return DoResolveCore (ec, left_orig, right_orig);
}
public Lifted (Expression expr, Unwrap unwrap, TypeSpec type)
{
this.expr = expr;
this.unwrap = unwrap;
this.loc = expr.Location;
this.type = type;
}
Expression ConvertExpression (ResolveContext ec)
{
// TODO: ImplicitConversionExists should take care of this
if (left.eclass == ExprClass.MethodGroup)
return null;
TypeSpec ltype = left.Type;
//
// If left is a nullable type and an implicit conversion exists from right to underlying type of left,
// the result is underlying type of left
//
if (ltype.IsNullableType) {
unwrap = Unwrap.Create (left, false);
if (unwrap == null)
return null;
//
// Reduce (left ?? null) to left
//
if (right.IsNull)
return ReducedExpression.Create (left, this);
if (Convert.ImplicitConversionExists (ec, right, unwrap.Type)) {
left = unwrap;
ltype = left.Type;
//
// If right is a dynamic expression, the result type is dynamic
//
if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
type = right.Type;
// Need to box underlying value type
left = Convert.ImplicitBoxingConversion (left, ltype, type);
return this;
}
right = Convert.ImplicitConversion (ec, right, ltype, loc);
type = ltype;
return this;
}
} else if (TypeSpec.IsReferenceType (ltype)) {
if (Convert.ImplicitConversionExists (ec, right, ltype)) {
//
// If right is a dynamic expression, the result type is dynamic
//
if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
type = right.Type;
return this;
}
//
// Reduce ("foo" ?? expr) to expression
//
Constant lc = left as Constant;
if (lc != null && !lc.IsDefaultValue)
return ReducedExpression.Create (lc, this);
//
// Reduce (left ?? null) to left OR (null-constant ?? right) to right
//
if (right.IsNull || lc != null)
return ReducedExpression.Create (lc != null ? right : left, this);
right = Convert.ImplicitConversion (ec, right, ltype, loc);
type = ltype;
return this;
}
//
// Special case null ?? null
//
if (ltype == right.Type) {
type = ltype;
return this;
}
} else {
return null;
}
TypeSpec rtype = right.Type;
if (!Convert.ImplicitConversionExists (ec, unwrap != null ? unwrap : left, rtype) || right.eclass == ExprClass.MethodGroup)
return null;
//
// Reduce (null ?? right) to right
//
if (left.IsNull)
return ReducedExpression.Create (right, this).Resolve (ec);
left = Convert.ImplicitConversion (ec, unwrap != null ? unwrap : left, rtype, loc);
type = rtype;
return this;
}
void EmitBitwiseBoolean(EmitContext ec)
{
Label load_left = ec.DefineLabel();
Label load_right = ec.DefineLabel();
Label end_label = ec.DefineLabel();
// null & value, null | value
if (left_unwrap == null)
{
left_unwrap = right_unwrap;
right_unwrap = null;
right = left;
}
left_unwrap.Emit(ec);
ec.Emit(OpCodes.Brtrue, load_right);
// value & null, value | null
if (right_unwrap != null)
{
right_unwrap.Emit(ec);
ec.Emit(OpCodes.Brtrue_S, load_left);
}
left_unwrap.EmitCheck(ec);
ec.Emit(OpCodes.Brfalse_S, load_right);
// load left
ec.MarkLabel(load_left);
if (Oper == Operator.BitwiseAnd)
{
left_unwrap.Load(ec);
}
else
{
if (right_unwrap == null)
{
right.Emit(ec);
if (right is EmptyConstantCast || right is EmptyCast)
{
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
}
}
else
{
right_unwrap.Load(ec);
right_unwrap = left_unwrap;
}
}
ec.Emit(OpCodes.Br_S, end_label);
// load right
ec.MarkLabel(load_right);
if (right_unwrap == null)
{
if (Oper == Operator.BitwiseAnd)
{
right.Emit(ec);
if (right is EmptyConstantCast || right is EmptyCast)
{
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
}
}
else
{
left_unwrap.Load(ec);
}
}
else
{
right_unwrap.Load(ec);
}
ec.MarkLabel(end_label);
}
public override bool Equals(object obj)
{
Unwrap uw = obj as Unwrap;
return(uw != null && expr.Equals(uw.expr));
}
Expression ConvertExpression(ResolveContext ec)
{
// TODO: ImplicitConversionExists should take care of this
if (left.eclass == ExprClass.MethodGroup)
{
return(null);
}
TypeSpec ltype = left.Type;
//
// If left is a nullable type and an implicit conversion exists from right to underlying type of left,
// the result is underlying type of left
//
if (ltype.IsNullableType)
{
unwrap = Unwrap.Create(left, false);
if (unwrap == null)
{
return(null);
}
//
// Reduce (left ?? null) to left
//
if (right.IsNull)
{
return(ReducedExpression.Create(left, this));
}
if (Convert.ImplicitConversionExists(ec, right, unwrap.Type))
{
left = unwrap;
ltype = left.Type;
//
// If right is a dynamic expression, the result type is dynamic
//
if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
{
type = right.Type;
// Need to box underlying value type
left = Convert.ImplicitBoxingConversion(left, ltype, type);
return(this);
}
right = Convert.ImplicitConversion(ec, right, ltype, loc);
type = ltype;
return(this);
}
}
else if (TypeSpec.IsReferenceType(ltype))
{
if (Convert.ImplicitConversionExists(ec, right, ltype))
{
//
// If right is a dynamic expression, the result type is dynamic
//
if (right.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
{
type = right.Type;
return(this);
}
//
// Reduce ("foo" ?? expr) to expression
//
Constant lc = left as Constant;
if (lc != null && !lc.IsDefaultValue)
{
return(ReducedExpression.Create(lc, this));
}
//
// Reduce (left ?? null) to left OR (null-constant ?? right) to right
//
if (right.IsNull || lc != null)
{
return(ReducedExpression.Create(lc != null ? right : left, this));
}
right = Convert.ImplicitConversion(ec, right, ltype, loc);
type = ltype;
return(this);
}
//
// Special case null ?? null
//
if (ltype == right.Type)
{
type = ltype;
return(this);
}
}
else
{
return(null);
}
TypeSpec rtype = right.Type;
if (!Convert.ImplicitConversionExists(ec, unwrap != null ? unwrap : left, rtype) || right.eclass == ExprClass.MethodGroup)
{
return(null);
}
//
// Reduce (null ?? right) to right
//
if (left.IsNull)
{
return(ReducedExpression.Create(right, this).Resolve(ec));
}
left = Convert.ImplicitConversion(ec, unwrap != null ? unwrap : left, rtype, loc);
type = rtype;
return(this);
}