| public static Create ( TypeSpec nullable, Location loc ) : Constant | ||
| nullable | TypeSpec | |
| loc | Location | |
| return | Constant | |
public override void Emit(EmitContext ec)
{
Label is_null_label = ec.DefineLabel();
Label end_label = ec.DefineLabel();
unwrap.EmitCheck(ec);
ec.Emit(OpCodes.Brfalse, is_null_label);
if (user_operator != null)
{
user_operator.Emit(ec);
}
else
{
EmitOperator(ec, NullableInfo.GetUnderlyingType(type));
}
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(is_null_label);
LiftedNull.Create(type, loc).Emit(ec);
ec.MarkLabel(end_label);
}
protected override void EmitOperation(EmitContext ec)
{
Label is_null_label = ec.DefineLabel();
Label end_label = ec.DefineLabel();
LocalTemporary lt = new LocalTemporary(type);
// Value is on the stack
lt.Store(ec);
var call = new CallEmitter();
call.InstanceExpression = lt;
call.EmitPredefined(ec, NullableInfo.GetHasValue(expr.Type), null);
ec.Emit(OpCodes.Brfalse, is_null_label);
call = new CallEmitter();
call.InstanceExpression = lt;
call.EmitPredefined(ec, NullableInfo.GetGetValueOrDefault(expr.Type), null);
lt.Release(ec);
base.EmitOperation(ec);
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(is_null_label);
LiftedNull.Create(type, loc).Emit(ec);
ec.MarkLabel(end_label);
}
protected override Expression DoResolve(ResolveContext ec)
{
//
// It's null when lifting non-nullable type
//
if (unwrap == null)
{
// S -> T? is wrap only
if (type.IsNullableType)
{
return(Wrap.Create(expr, type));
}
// S -> T can be simplified
return(expr);
}
// Wrap target for T?
if (type.IsNullableType)
{
if (!expr.Type.IsNullableType)
{
expr = Wrap.Create(expr, type);
if (expr == null)
{
return(null);
}
}
null_value = LiftedNull.Create(type, loc);
}
else if (TypeSpec.IsValueType(type))
{
null_value = LiftedNull.Create(type, loc);
}
else
{
null_value = new NullConstant(type, loc);
}
eclass = ExprClass.Value;
return(this);
}
void EmitBitwiseBoolean(EmitContext ec)
{
Label load_left = ec.DefineLabel();
Label load_right = ec.DefineLabel();
Label end_label = ec.DefineLabel();
Label is_null_label = ec.DefineLabel();
bool or = Binary.Oper == Binary.Operator.BitwiseOr;
//
// Both operands are bool? types
//
if (UnwrapLeft != null && UnwrapRight != null)
{
if (ec.HasSet(BuilderContext.Options.AsyncBody) && Binary.Right.ContainsEmitWithAwait())
{
Left = Left.EmitToField(ec);
Right = Right.EmitToField(ec);
}
else
{
UnwrapLeft.Store(ec);
UnwrapRight.Store(ec);
}
Left.Emit(ec);
ec.Emit(OpCodes.Brtrue_S, load_right);
Right.Emit(ec);
ec.Emit(OpCodes.Brtrue_S, load_left);
UnwrapLeft.EmitCheck(ec);
ec.Emit(OpCodes.Brfalse_S, load_right);
// load left
ec.MarkLabel(load_left);
if (or)
{
UnwrapRight.Load(ec);
}
else
{
UnwrapLeft.Load(ec);
}
ec.Emit(OpCodes.Br_S, end_label);
// load right
ec.MarkLabel(load_right);
if (or)
{
UnwrapLeft.Load(ec);
}
else
{
UnwrapRight.Load(ec);
}
ec.MarkLabel(end_label);
return;
}
//
// Faster version when one operand is bool
//
if (UnwrapLeft == null)
{
//
// (bool, bool?)
//
// Optimizes remaining (false & bool?), (true | bool?) which are not easy to handle
// in binary expression reduction
//
var c = Left as BoolConstant;
if (c != null)
{
// Keep evaluation order
UnwrapRight.Store(ec);
ec.EmitInt(or ? 1 : 0);
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
}
else if (Left.IsNull)
{
UnwrapRight.Emit(ec);
ec.Emit(or ? OpCodes.Brfalse_S : OpCodes.Brtrue_S, is_null_label);
UnwrapRight.Load(ec);
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(is_null_label);
LiftedNull.Create(type, loc).Emit(ec);
}
else
{
Left.Emit(ec);
ec.Emit(or ? OpCodes.Brfalse_S : OpCodes.Brtrue_S, load_right);
ec.EmitInt(or ? 1 : 0);
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(load_right);
UnwrapRight.Original.Emit(ec);
}
}
else
{
//
// (bool?, bool)
//
// Keep left-right evaluation order
UnwrapLeft.Store(ec);
//
// Optimizes remaining (bool? & false), (bool? | true) which are not easy to handle
// in binary expression reduction
//
var c = Right as BoolConstant;
if (c != null)
{
ec.EmitInt(or ? 1 : 0);
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
}
else if (Right.IsNull)
{
UnwrapLeft.Emit(ec);
ec.Emit(or ? OpCodes.Brfalse_S : OpCodes.Brtrue_S, is_null_label);
UnwrapLeft.Load(ec);
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(is_null_label);
LiftedNull.Create(type, loc).Emit(ec);
}
else
{
Right.Emit(ec);
ec.Emit(or ? OpCodes.Brfalse_S : OpCodes.Brtrue_S, load_right);
ec.EmitInt(or ? 1 : 0);
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(load_right);
UnwrapLeft.Load(ec);
}
}
ec.MarkLabel(end_label);
}
public override void Emit(EmitContext ec)
{
if (IsBitwiseBoolean && UserOperator == null)
{
EmitBitwiseBoolean(ec);
return;
}
if ((Binary.Oper & Binary.Operator.EqualityMask) != 0)
{
EmitEquality(ec);
return;
}
Label is_null_label = ec.DefineLabel();
Label end_label = ec.DefineLabel();
if (ec.HasSet(BuilderContext.Options.AsyncBody) && Right.ContainsEmitWithAwait())
{
Left = Left.EmitToField(ec);
Right = Right.EmitToField(ec);
}
if (UnwrapLeft != null)
{
UnwrapLeft.EmitCheck(ec);
}
//
// Don't emit HasValue check when left and right expressions are same
//
if (UnwrapRight != null && !Binary.Left.Equals(Binary.Right))
{
UnwrapRight.EmitCheck(ec);
if (UnwrapLeft != null)
{
ec.Emit(OpCodes.And);
}
}
ec.Emit(OpCodes.Brfalse, is_null_label);
if (UserOperator != null)
{
var args = new Arguments(2);
args.Add(new Argument(Left));
args.Add(new Argument(Right));
var call = new CallEmitter();
call.EmitPredefined(ec, UserOperator, args);
}
else
{
Binary.EmitOperator(ec, Left, Right);
}
//
// Wrap the result when the operator return type is nullable type
//
if (type.IsNullableType)
{
ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type));
}
ec.Emit(OpCodes.Br_S, end_label);
ec.MarkLabel(is_null_label);
if ((Binary.Oper & Binary.Operator.ComparisonMask) != 0)
{
ec.EmitInt(0);
}
else
{
LiftedNull.Create(type, loc).Emit(ec);
}
ec.MarkLabel(end_label);
}
