// Miguel de Icaza (miguel@ximian.com)
// Marek Safar (marek.safar@gmail.com)
//
-// Licensed under the terms of the GNU GPL
+// Dual licensed under the terms of the MIT X11 or GNU GPL
//
-// (C) 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
-// (C) 2004 Novell, Inc
+// Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
+// Copyright 2004-2008 Novell, Inc
//
using System;
: this (new TypeExpression (type, loc), loc)
{ }
- public override string Name {
- get { return underlying.ToString () + "?"; }
- }
-
- public override string FullName {
- get { return underlying.ToString () + "?"; }
- }
-
protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
{
TypeArguments args = new TypeArguments (loc);
Constructor = type.GetConstructor (new Type[] { UnderlyingType });
}
}
-
- public class HasValue : Expression
- {
- Expression expr;
- NullableInfo info;
-
- private HasValue (Expression expr)
- {
- this.expr = expr;
- }
-
- public static Expression Create (Expression expr, EmitContext ec)
- {
- return new HasValue (expr).Resolve (ec);
- }
-
- public override void Emit (EmitContext ec)
- {
- IMemoryLocation memory_loc = expr as IMemoryLocation;
- if (memory_loc == null) {
- LocalTemporary temp = new LocalTemporary (expr.Type);
- expr.Emit (ec);
- temp.Store (ec);
- memory_loc = temp;
- }
- memory_loc.AddressOf (ec, AddressOp.LoadStore);
- ec.ig.EmitCall (OpCodes.Call, info.HasValue, null);
- }
-
- public override Expression DoResolve (EmitContext ec)
- {
- this.info = new NullableInfo (expr.Type);
-
- type = TypeManager.bool_type;
- eclass = expr.eclass;
- return this;
- }
- }
public class Unwrap : Expression, IMemoryLocation, IAssignMethod
{
NullableInfo info;
LocalTemporary temp;
- bool has_temp;
protected Unwrap (Expression expr)
{
if (expr == null)
return null;
- temp = new LocalTemporary (expr.Type);
-
info = new NullableInfo (expr.Type);
type = info.UnderlyingType;
eclass = expr.eclass;
public override void Emit (EmitContext ec)
{
+ Store (ec);
AddressOf (ec, AddressOp.LoadStore);
ec.ig.EmitCall (OpCodes.Call, info.Value, null);
}
public void EmitCheck (EmitContext ec)
{
+ Store (ec);
AddressOf (ec, AddressOp.LoadStore);
ec.ig.EmitCall (OpCodes.Call, info.HasValue, null);
}
public void EmitGetValueOrDefault (EmitContext ec)
{
+ Store (ec);
AddressOf (ec, AddressOp.LoadStore);
ec.ig.EmitCall (OpCodes.Call, info.GetValueOrDefault, null);
}
}
}
- public void Store (EmitContext ec)
+ void Store (EmitContext ec)
{
- create_temp (ec);
- }
+ if (expr is VariableReference)
+ return;
- void create_temp (EmitContext ec)
- {
- if ((temp != null) && !has_temp) {
- expr.Emit (ec);
- temp.Store (ec);
- has_temp = true;
- }
+ if (temp != null)
+ return;
+
+ expr.Emit (ec);
+ LocalVariable.Store (ec);
}
- public void LoadTemporary (EmitContext ec)
+ public void Load (EmitContext ec)
{
- temp.Emit (ec);
+ if (expr is VariableReference)
+ expr.Emit (ec);
+ else
+ LocalVariable.Emit (ec);
}
public void AddressOf (EmitContext ec, AddressOp mode)
{
- create_temp (ec);
- if (temp != null)
- temp.AddressOf (ec, AddressOp.LoadStore);
+ IMemoryLocation ml = expr as VariableReference;
+ if (ml != null)
+ ml.AddressOf (ec, mode);
else
- ((IMemoryLocation) expr).AddressOf (ec, AddressOp.LoadStore);
+ LocalVariable.AddressOf (ec, mode);
+ }
+
+ //
+ // Keeps result of non-variable expression
+ //
+ LocalTemporary LocalVariable {
+ get {
+ if (temp == null)
+ temp = new LocalTemporary (info.Type);
+ return temp;
+ }
}
public void Emit (EmitContext ec, bool leave_copy)
{
- create_temp (ec);
- if (leave_copy) {
- if (temp != null)
- temp.Emit (ec);
- else
- expr.Emit (ec);
- }
+ if (leave_copy)
+ Load (ec);
Emit (ec);
}
eclass = ExprClass.Value;
}
+ public override Expression CreateExpressionTree (EmitContext ec)
+ {
+ throw new NotSupportedException ("ET");
+ }
+
public override Expression DoResolve (EmitContext ec)
{
return this;
}
}
- public class Wrap : EmptyCast
+ public class Wrap : TypeCast
{
readonly NullableInfo info;
eclass = ExprClass.Value;
}
- public static new Expression Create (Expression expr, Type type)
+ public static Expression Create (Expression expr, Type type)
{
+ //
+ // Avoid unwraping and wraping of the same type
+ //
+ Unwrap unwrap = expr as Unwrap;
+ if (unwrap != null && TypeManager.IsEqual (expr.Type, TypeManager.GetTypeArguments (type) [0]))
+ return unwrap.Original;
+
return new Wrap (expr, type);
}
}
}
- class LiftedWrap : Wrap
- {
- public LiftedWrap (Expression expr, Type type)
- : base (expr, type)
- {
- }
-
- public override Expression CreateExpressionTree (EmitContext ec)
- {
- return child.CreateExpressionTree (ec);
- }
- }
-
//
// Represents null literal lifted to nullable type
//
return new LiftedNull (nullable, loc);
}
+ public static Expression CreateFromExpression (Expression e)
+ {
+ Report.Warning (458, 2, e.Location, "The result of the expression is always `null' of type `{0}'",
+ TypeManager.CSharpName (e.Type));
+
+ return ReducedExpression.Create (Create (e.Type, e.Location), e);
+ }
+
public override Expression CreateExpressionTree (EmitContext ec)
{
ArrayList args = new ArrayList (2);
public override Expression CreateExpressionTree (EmitContext ec)
{
- return underlying.CreateExpressionTree (ec);
+ ArrayList args = new ArrayList (2);
+ args.Add (new Argument (expr.CreateExpressionTree (ec)));
+ args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
+ return CreateExpressionFactoryCall ("Convert", args);
}
public override Expression DoResolve (EmitContext ec)
Type type = TypeManager.GetTypeArguments (TargetType) [0];
if (IsUser) {
- return Convert.UserDefinedConversion (ec, unwrap, type, loc, IsExplicit);
+ if (IsExplicit)
+ return Convert.ExplicitUserConversion (ec, unwrap, type, loc);
+ else
+ return Convert.ImplicitUserConversion (ec, unwrap, type, loc);
} else {
if (IsExplicit)
return Convert.ExplicitConversion (ec, unwrap, type, loc);
}
}
- public class LiftedUnaryOperator : Lifted
+ public class LiftedUnaryOperator : Unary, IMemoryLocation
{
- public readonly Unary.Operator Oper;
+ Unwrap unwrap;
+ Expression user_operator;
public LiftedUnaryOperator (Unary.Operator op, Expression expr, Location loc)
- : base (expr, loc)
+ : base (op, expr, loc)
{
- this.Oper = op;
}
- protected override Expression ResolveUnderlying (Expression unwrap, EmitContext ec)
+ public void AddressOf (EmitContext ec, AddressOp mode)
+ {
+ unwrap.AddressOf (ec, mode);
+ }
+
+ public override Expression CreateExpressionTree (EmitContext ec)
+ {
+ if (user_operator != null)
+ return user_operator.CreateExpressionTree (ec);
+
+ if (Oper == Operator.UnaryPlus)
+ return Expr.CreateExpressionTree (ec);
+
+ return base.CreateExpressionTree (ec);
+ }
+
+ public override Expression DoResolve (EmitContext ec)
{
- return new Unary (Oper, unwrap, loc).Resolve (ec);
+ if (eclass != ExprClass.Invalid)
+ return this;
+
+ unwrap = Unwrap.Create (Expr, ec);
+ 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;
+ }
+
+ public override void Emit (EmitContext ec)
+ {
+ ILGenerator ig = ec.ig;
+ Label is_null_label = ig.DefineLabel ();
+ Label end_label = ig.DefineLabel ();
+
+ unwrap.EmitCheck (ec);
+ ig.Emit (OpCodes.Brfalse, is_null_label);
+
+ NullableInfo ni = new NullableInfo (type);
+
+ if (user_operator != null) {
+ user_operator.Emit (ec);
+ } else {
+ EmitOperator (ec, ni.UnderlyingType);
+ }
+
+ ig.Emit (OpCodes.Newobj, ni.Constructor);
+ ig.Emit (OpCodes.Br_S, end_label);
+
+ ig.MarkLabel (is_null_label);
+ LiftedNull.Create (type, loc).Emit (ec);
+
+ ig.MarkLabel (end_label);
+ }
+
+ Expression LiftExpression (EmitContext ec, Expression expr)
+ {
+ TypeExpr lifted_type = new NullableType (expr.Type, expr.Location);
+ lifted_type = lifted_type.ResolveAsTypeTerminal (ec, false);
+ if (lifted_type == null)
+ return null;
+
+ expr.Type = lifted_type.Type;
+ return expr;
+ }
+
+ protected override Expression ResolveEnumOperator (EmitContext ec, Expression expr)
+ {
+ expr = base.ResolveEnumOperator (ec, expr);
+ if (expr == null)
+ return null;
+
+ Expr = LiftExpression (ec, Expr);
+ return LiftExpression (ec, expr);
+ }
+
+ protected override Expression ResolveUserOperator (EmitContext ec, Expression expr)
+ {
+ expr = base.ResolveUserOperator (ec, expr);
+ if (expr == null)
+ return null;
+
+ //
+ // When a user operator is of non-nullable type
+ //
+ if (Expr is Unwrap) {
+ user_operator = LiftExpression (ec, expr);
+ return user_operator;
+ }
+
+ return expr;
}
}
Unwrap left_unwrap, right_unwrap;
bool left_null_lifted, right_null_lifted;
Expression left_orig, right_orig;
+ Expression user_operator;
+ ConstructorInfo wrap_ctor;
public LiftedBinaryOperator (Binary.Operator op, Expression left, Expression right,
Location loc)
this.loc = loc;
}
+ public override Expression CreateExpressionTree (EmitContext ec)
+ {
+ if (user_operator != null)
+ return user_operator.CreateExpressionTree (ec);
+
+ return base.CreateExpressionTree (ec);
+ }
+
//
// CSC 2 has this behavior, it allows structs to be compared
// with the null literal *outside* of a generics context and
if (eclass != ExprClass.Invalid)
return this;
- // TODO: How does it work with use-operators?
- if ((Oper == Binary.Operator.LogicalAnd) ||
- (Oper == Binary.Operator.LogicalOr)) {
+ if ((Oper & Operator.LogicalMask) != 0) {
Error_OperatorCannotBeApplied (left, right);
return 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 is NullLiteral) {
left = right;
left_null_lifted = true;
+ type = TypeManager.bool_type;
}
if (right is NullLiteral) {
right = left;
right_null_lifted = true;
+ type = TypeManager.bool_type;
}
eclass = ExprClass.Value;
- Expression expr = DoResolveCore (ec, left_orig, right_orig);
- if (expr != this || (Oper & Operator.ComparisonMask) != 0)
- return expr;
-
- TypeExpr target_type = new NullableType (type, loc);
- target_type = target_type.ResolveAsTypeTerminal (ec, false);
- if (target_type == null)
- return null;
-
- type = target_type.Type;
- return this;
+ return DoResolveCore (ec, left_orig, right_orig);
}
void EmitBitwiseBoolean (EmitContext ec)
ig.MarkLabel (load_left);
if (Oper == Operator.BitwiseAnd) {
- left_unwrap.LoadTemporary (ec);
+ left_unwrap.Load (ec);
} else {
- right_unwrap.LoadTemporary (ec);
+ right_unwrap.Load (ec);
right_unwrap = left_unwrap;
}
ig.Emit (OpCodes.Br_S, end_label);
// load right
ig.MarkLabel (load_right);
- right_unwrap.LoadTemporary (ec);
+ right_unwrap.Load (ec);
ig.MarkLabel (end_label);
}
- void EmitEquality (EmitContext ec)
+ //
+ // Emits optimized equality or inequality operator when possible
+ //
+ bool EmitEquality (EmitContext ec)
{
ILGenerator ig = ec.ig;
- Label both_have_value_label = ig.DefineLabel ();
- Label end_label = ig.DefineLabel ();
-
//
- // Both are nullable types
+ // Either left or right is null
//
- if (left_unwrap != null && right_unwrap != null && !right.IsNull && !left.IsNull) {
- Label dissimilar_label = ig.DefineLabel ();
-
- left_unwrap.EmitGetValueOrDefault (ec);
- right_unwrap.EmitGetValueOrDefault (ec);
- ig.Emit (OpCodes.Bne_Un_S, dissimilar_label);
-
+ if (left_unwrap != null && (right_null_lifted || right.IsNull)) {
left_unwrap.EmitCheck (ec);
- right_unwrap.EmitCheck (ec);
- if (Oper == Operator.Inequality)
- ig.Emit (OpCodes.Xor);
- else
- ig.Emit (OpCodes.Ceq);
-
- ig.Emit (OpCodes.Br_S, end_label);
-
- ig.MarkLabel (dissimilar_label);
- if (Oper == Operator.Inequality)
- ig.Emit (OpCodes.Ldc_I4_1);
- else
+ if (Oper == Binary.Operator.Equality) {
ig.Emit (OpCodes.Ldc_I4_0);
-
- ig.MarkLabel (end_label);
- return;
+ ig.Emit (OpCodes.Ceq);
+ }
+ return true;
}
- //
- // Either left or right is nullable
- //
- if (left_unwrap != null) {
- left_unwrap.EmitCheck (ec);
- if (right.IsNull) {
- if (Oper == Binary.Operator.Equality) {
- ig.Emit (OpCodes.Ldc_I4_0);
- ig.Emit (OpCodes.Ceq);
- }
- return;
- }
- ig.Emit (OpCodes.Brtrue_S, both_have_value_label);
- } else {
+ if (right_unwrap != null && (left_null_lifted || left.IsNull)) {
right_unwrap.EmitCheck (ec);
- if (left.IsNull) {
- if (Oper == Binary.Operator.Equality) {
- ig.Emit (OpCodes.Ldc_I4_0);
- ig.Emit (OpCodes.Ceq);
- }
- return;
+ if (Oper == Binary.Operator.Equality) {
+ ig.Emit (OpCodes.Ldc_I4_0);
+ ig.Emit (OpCodes.Ceq);
}
- ig.Emit (OpCodes.Brtrue_S, both_have_value_label);
+ return true;
}
- if (Oper == Binary.Operator.Equality)
- ig.Emit (OpCodes.Ldc_I4_0);
- else
- ig.Emit (OpCodes.Ldc_I4_1);
- ig.Emit (OpCodes.Br, end_label);
+ if (user_operator != null)
+ return false;
- ig.MarkLabel (both_have_value_label);
- EmitOperator (ec);
+ Label dissimilar_label = ig.DefineLabel ();
+ Label end_label = ig.DefineLabel ();
- ig.MarkLabel (end_label);
- }
+ if (left_unwrap != null)
+ left_unwrap.EmitGetValueOrDefault (ec);
+ else
+ left.Emit (ec);
- void EmitComparision (EmitContext ec)
- {
- ILGenerator ig = ec.ig;
+ if (right_unwrap != null)
+ right_unwrap.EmitGetValueOrDefault (ec);
+ else
+ right.Emit (ec);
- Label is_null_label = ig.DefineLabel ();
- Label end_label = ig.DefineLabel ();
+ ig.Emit (OpCodes.Bne_Un_S, dissimilar_label);
- if (left_unwrap != null) {
+ if (left_unwrap != null)
left_unwrap.EmitCheck (ec);
- ig.Emit (OpCodes.Brfalse, is_null_label);
- }
-
- if (right_unwrap != null) {
+ if (right_unwrap != null)
right_unwrap.EmitCheck (ec);
- ig.Emit (OpCodes.Brfalse, is_null_label);
+
+ if (left_unwrap != null && right_unwrap != null) {
+ if (Oper == Operator.Inequality)
+ ig.Emit (OpCodes.Xor);
+ else
+ ig.Emit (OpCodes.Ceq);
+ } else {
+ if (Oper == Operator.Inequality) {
+ ig.Emit (OpCodes.Ldc_I4_0);
+ ig.Emit (OpCodes.Ceq);
+ }
}
- EmitOperator (ec);
ig.Emit (OpCodes.Br_S, end_label);
- ig.MarkLabel (is_null_label);
- ig.Emit (OpCodes.Ldc_I4_0);
+ ig.MarkLabel (dissimilar_label);
+ if (Oper == Operator.Inequality)
+ ig.Emit (OpCodes.Ldc_I4_1);
+ else
+ ig.Emit (OpCodes.Ldc_I4_0);
ig.MarkLabel (end_label);
+ return true;
}
public override void EmitBranchable (EmitContext ec, Label target, bool onTrue)
public override void Emit (EmitContext ec)
{
- if (left_unwrap != null)
- left_unwrap.Store (ec);
- if (right_unwrap != null)
- right_unwrap.Store (ec);
+ //
+ // Optimize same expression operation
+ //
+ if (right_unwrap != null && right.Equals (left))
+ right_unwrap = left_unwrap;
- if (IsBitwiseBoolean) {
+ if (user_operator == null && IsBitwiseBoolean) {
EmitBitwiseBoolean (ec);
return;
}
if ((Oper & Operator.EqualityMask) != 0) {
- EmitEquality (ec);
- return;
- }
-
- if ((Oper & Operator.ComparisonMask) != 0) {
- EmitComparision (ec);
- return;
+ if (EmitEquality (ec))
+ return;
}
ILGenerator ig = ec.ig;
ig.Emit (OpCodes.Brfalse, is_null_label);
}
- if (right_unwrap != null) {
+ //
+ // Don't emit HasValue check when left and right expressions are same
+ //
+ if (right_unwrap != null && !left.Equals (right)) {
right_unwrap.EmitCheck (ec);
ig.Emit (OpCodes.Brfalse, is_null_label);
}
- base.EmitOperator (ec);
+ EmitOperator (ec, left.Type);
+
+ if (wrap_ctor != null)
+ ig.Emit (OpCodes.Newobj, wrap_ctor);
ig.Emit (OpCodes.Br_S, end_label);
ig.MarkLabel (is_null_label);
- LiftedNull.Create (type, loc).Emit (ec);
+
+ if ((Oper & Operator.ComparisonMask) != 0) {
+ if (Oper == Operator.Equality)
+ ig.Emit (OpCodes.Ldc_I4_1);
+ else
+ ig.Emit (OpCodes.Ldc_I4_0);
+ } else {
+ LiftedNull.Create (type, loc).Emit (ec);
+ }
ig.MarkLabel (end_label);
}
+ protected override void EmitOperator (EmitContext ec, Type l)
+ {
+ if (user_operator != null) {
+ user_operator.Emit (ec);
+ return;
+ }
+
+ if (TypeManager.IsNullableType (l))
+ l = TypeManager.GetTypeArguments (l) [0];
+
+ base.EmitOperator (ec, l);
+ }
+
bool IsBitwiseBoolean {
get {
return (Oper & Operator.BitwiseMask) != 0 && left_unwrap != null && right_unwrap != null &&
if (lifted_type == null)
return null;
- left = EmptyCast.Create (left, lifted_type.Type);
+ if (left is UserCast || left is TypeCast)
+ left.Type = lifted_type.Type;
+ else
+ left = EmptyCast.Create (left, lifted_type.Type);
}
if (right_unwrap == null || right_null_lifted || !TypeManager.IsEqual (right_unwrap.Type, right.Type)) {
if (lifted_type == null)
return null;
- right = EmptyCast.Create (right, lifted_type.Type);
+ if (right is UserCast || right is TypeCast)
+ right.Type = lifted_type.Type;
+ else
+ right = EmptyCast.Create (right, lifted_type.Type);
+ }
+
+ if ((Oper & Operator.ComparisonMask) == 0) {
+ lifted_type = new NullableType (res_expr.Type, loc);
+ lifted_type = lifted_type.ResolveAsTypeTerminal (ec, false);
+ if (lifted_type == null)
+ return null;
+
+ wrap_ctor = new NullableInfo (lifted_type.Type).Constructor;
+ type = res_expr.Type = lifted_type.Type;
}
if (left_null_lifted) {
left = LiftedNull.Create (right.Type, left.Location);
+ if ((Oper & (Operator.ArithmeticMask | Operator.ShiftMask)) != 0)
+ return LiftedNull.CreateFromExpression (res_expr);
+
//
// Value types and null comparison
//
if (right_null_lifted) {
right = LiftedNull.Create (left.Type, right.Location);
+ if ((Oper & (Operator.ArithmeticMask | Operator.ShiftMask)) != 0)
+ return LiftedNull.CreateFromExpression (res_expr);
+
//
// Value types and null comparison
//
return CreateNullConstant (left_orig).Resolve (ec);
}
- // TODO: Handle bitwise bool
- if ((Oper & Operator.ComparisonMask) != 0 || IsBitwiseBoolean)
- return res_expr;
-
- lifted_type = new NullableType (res_expr.Type, loc);
- lifted_type = lifted_type.ResolveAsTypeTerminal (ec, false);
- if (lifted_type == null)
- return null;
-
- return new LiftedWrap (res_expr, lifted_type.Type).Resolve (ec);
+ return res_expr;
}
- protected override Expression ResolveOperatorPredefined (EmitContext ec, Binary.PredefinedOperator [] operators, bool primitives_only)
+ protected override Expression ResolveOperatorPredefined (EmitContext ec, Binary.PredefinedOperator [] operators, bool primitives_only, Type enum_type)
{
- Expression e = base.ResolveOperatorPredefined (ec, operators, primitives_only);
+ Expression e = base.ResolveOperatorPredefined (ec, operators, primitives_only, enum_type);
- if (e == this)
+ if (e == this || enum_type != null)
return LiftResult (ec, e);
//
if (expr == null)
return null;
- return LiftResult (ec, expr);
+ expr = LiftResult (ec, expr);
+ if (expr is Constant)
+ return expr;
+
+ type = expr.Type;
+ user_operator = expr;
+ return this;
}
}
public override Expression CreateExpressionTree (EmitContext ec)
{
+ if (left is NullLiteral)
+ Report.Error (845, loc, "An expression tree cannot contain a coalescing operator with null left side");
+
UserCast uc = left as UserCast;
Expression conversion = null;
if (uc != null) {
eclass = ExprClass.Value;
Type ltype = left.Type, rtype = right.Type;
- Expression expr;
-
- if (TypeManager.IsNullableType (ltype)) {
- NullableInfo info = new NullableInfo (ltype);
+ //
+ // 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 (TypeManager.IsNullableType (ltype) && left.eclass != ExprClass.MethodGroup) {
unwrap = Unwrap.Create (left, ec);
if (unwrap == null)
return null;
- expr = Convert.ImplicitConversion (ec, right, info.UnderlyingType, loc);
- if (expr != null) {
+ if (Convert.ImplicitConversionExists (ec, right, unwrap.Type)) {
left = unwrap;
- right = expr;
- type = expr.Type;
+ type = left.Type;
+ right = Convert.ImplicitConversion (ec, right, type, loc);
+ return this;
+ }
+ } else if (TypeManager.IsReferenceType (ltype) && right.eclass != ExprClass.MethodGroup) {
+ if (Convert.ImplicitConversionExists (ec, right, ltype)) {
+ //
+ // Reduce (constant ?? expr) to constant
+ //
+ Constant lc = left as Constant;
+ if (lc != null && !lc.IsDefaultValue)
+ return new SideEffectConstant (lc, right, loc).Resolve (ec);
+
+ //
+ // Reduce (left ?? null) to left OR (null-constant ?? right) to right
+ //
+ if (right.IsNull || lc != null)
+ return ReducedExpression.Create (lc != null ? right : left, this).Resolve (ec);
+
+ right = Convert.ImplicitConversion (ec, right, ltype, loc);
+ type = left.Type;
return this;
}
- } else if (!TypeManager.IsReferenceType (ltype)) {
- Binary.Error_OperatorCannotBeApplied (loc, "??", ltype, rtype);
+ } else {
+ Binary.Error_OperatorCannotBeApplied (left, right, "??", loc);
return null;
}
- expr = Convert.ImplicitConversion (ec, right, ltype, loc);
- if (expr != null) {
- type = expr.Type;
- right = expr;
- return this;
+ if (!Convert.ImplicitConversionExists (ec, unwrap != null ? unwrap : left, rtype)) {
+ Binary.Error_OperatorCannotBeApplied (left, right, "??", loc);
+ return null;
}
- Expression left_null = unwrap != null ? unwrap : left;
- expr = Convert.ImplicitConversion (ec, left_null, rtype, loc);
- if (expr != null) {
- left = expr;
- type = rtype;
- return this;
- }
+ //
+ // Reduce (null ?? right) to right
+ //
+ if (left.IsNull)
+ return ReducedExpression.Create (right, this).Resolve (ec);
- Binary.Error_OperatorCannotBeApplied (loc, "??", ltype, rtype);
- return null;
+ left = Convert.ImplicitConversion (ec, unwrap != null ? unwrap : left, rtype, loc);
+ type = rtype;
+ return this;
}
public override void Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
- Label is_null_label = ig.DefineLabel ();
Label end_label = ig.DefineLabel ();
if (unwrap != null) {
+ Label is_null_label = ig.DefineLabel ();
+
unwrap.EmitCheck (ec);
ig.Emit (OpCodes.Brfalse, is_null_label);
right.Emit (ec);
ig.MarkLabel (end_label);
- } else {
- left.Emit (ec);
- ig.Emit (OpCodes.Dup);
- ig.Emit (OpCodes.Brtrue, end_label);
+ return;
+ }
- ig.MarkLabel (is_null_label);
+ left.Emit (ec);
- ig.Emit (OpCodes.Pop);
- right.Emit (ec);
+ ig.Emit (OpCodes.Dup);
+ ig.Emit (OpCodes.Brtrue, end_label);
- ig.MarkLabel (end_label);
- }
+ ig.Emit (OpCodes.Pop);
+ right.Emit (ec);
+
+ ig.MarkLabel (end_label);
}
+
protected override void CloneTo (CloneContext clonectx, Expression t)
{
NullCoalescingOperator target = (NullCoalescingOperator) t;
public class LiftedUnaryMutator : ExpressionStatement
{
public readonly UnaryMutator.Mode Mode;
- Expression expr, null_value;
+ Expression expr;
UnaryMutator underlying;
Unwrap unwrap;
eclass = ExprClass.Value;
}
+ public override Expression CreateExpressionTree (EmitContext ec)
+ {
+ return new SimpleAssign (this, this).CreateExpressionTree (ec);
+ }
+
public override Expression DoResolve (EmitContext ec)
{
expr = expr.Resolve (ec);
return null;
type = expr.Type;
- null_value = LiftedNull.Create (type, loc);
return this;
}
unwrap.EmitCheck (ec);
ig.Emit (OpCodes.Brfalse, is_null_label);
- if (is_expr)
+ if (is_expr) {
underlying.Emit (ec);
- else
+ ig.Emit (OpCodes.Br_S, end_label);
+ } else {
underlying.EmitStatement (ec);
- ig.Emit (OpCodes.Br, end_label);
+ }
ig.MarkLabel (is_null_label);
if (is_expr)
- null_value.Emit (ec);
+ LiftedNull.Create (type, loc).Emit (ec);
ig.MarkLabel (end_label);
}
projects / mono.git / blobdiff