Esempio n. 1
0
        public override void Emit(EmitContext ec)
        {
            // TODO: generate less temporary variables
            LocalTemporary value_target = new LocalTemporary(type);

            value_target.AddressOf(ec, AddressOp.Store);
            ec.Emit(OpCodes.Initobj, type);
            value_target.Emit(ec);
            value_target.Release(ec);
        }
Esempio n. 2
0
		public override void Emit (EmitContext ec)
		{
			// TODO: generate less temporary variables
			LocalTemporary value_target = new LocalTemporary (type);

			value_target.AddressOf (ec, AddressOp.Store);
			ec.Emit (OpCodes.Initobj, type);
			value_target.Emit (ec);
		}
Esempio n. 3
0
        public override void Emit(EmitContext ec)
        {
            Label end_label = ec.DefineLabel();

            if (unwrap != null)
            {
                Label is_null_label = ec.DefineLabel();

                unwrap.EmitCheck(ec);
                ec.Emit(OpCodes.Brfalse, is_null_label);

                //
                // When both expressions are nullable the unwrap
                // is needed only for null check not for value uwrap
                //
                if (type.IsNullableType && TypeSpecComparer.IsEqual(NullableInfo.GetUnderlyingType(type), unwrap.Type))
                {
                    unwrap.Load(ec);
                }
                else
                {
                    left.Emit(ec);
                }

                ec.Emit(OpCodes.Br, end_label);

                ec.MarkLabel(is_null_label);
                right.Emit(ec);

                ec.MarkLabel(end_label);
                return;
            }

            //
            // Null check is done on original expression not after expression is converted to
            // result type. This is in most cases same but when user conversion is involved
            // we can end up in situation when use operator does the null handling which is
            // not what the operator is supposed to do
            //
            var op_expr = left as UserCast;

            if (op_expr != null)
            {
                op_expr.Source.Emit(ec);
                LocalTemporary temp;

                // TODO: More load kinds can be special cased
                if (!(op_expr.Source is VariableReference))
                {
                    temp = new LocalTemporary(op_expr.Source.Type);
                    temp.Store(ec);
                    temp.Emit(ec);
                    op_expr.Source = temp;
                }
                else
                {
                    temp = null;
                }

                var right_label = ec.DefineLabel();
                ec.Emit(OpCodes.Brfalse_S, right_label);
                left.Emit(ec);
                ec.Emit(OpCodes.Br, end_label);
                ec.MarkLabel(right_label);

                if (temp != null)
                {
                    temp.Release(ec);
                }
            }
            else
            {
                //
                // Common case where expression is not modified before null check and
                // we generate better/smaller code
                //
                left.Emit(ec);
                ec.Emit(OpCodes.Dup);

                // Only to make verifier happy
                if (left.Type.IsGenericParameter)
                {
                    ec.Emit(OpCodes.Box, left.Type);
                }

                ec.Emit(OpCodes.Brtrue, end_label);

                ec.Emit(OpCodes.Pop);
            }

            right.Emit(ec);

            ec.MarkLabel(end_label);
        }
Esempio n. 4
0
		public override void Emit (EmitContext ec)
		{
			Label end_label = ec.DefineLabel ();

			if (unwrap != null) {
				Label is_null_label = ec.DefineLabel ();

				unwrap.EmitCheck (ec);
				ec.Emit (OpCodes.Brfalse, is_null_label);

				//
				// When both expressions are nullable the unwrap
				// is needed only for null check not for value uwrap
				//
				if (type.IsNullableType && TypeSpecComparer.IsEqual (NullableInfo.GetUnderlyingType (type), unwrap.Type))
					unwrap.Load (ec);
				else
					left.Emit (ec);

				ec.Emit (OpCodes.Br, end_label);

				ec.MarkLabel (is_null_label);
				right.Emit (ec);

				ec.MarkLabel (end_label);
				return;
			}

			//
			// Null check is done on original expression not after expression is converted to
			// result type. This is in most cases same but when user conversion is involved
			// we can end up in situation when user operator does the null handling which is
			// not what the operator is supposed to do.
			// There is tricky case where cast of left expression is meant to be cast of
			// whole source expression (null check is done on it) and cast from right-to-left
			// conversion needs to do null check on unconverted source expression.
			//
			if (user_conversion_left) {
				var op_expr = (UserCast) left;

				op_expr.Source.Emit (ec);
				LocalTemporary temp;

				// TODO: More load kinds can be special cased
				if (!(op_expr.Source is VariableReference)) {
					temp = new LocalTemporary (op_expr.Source.Type);
					temp.Store (ec);
					temp.Emit (ec);
					op_expr.Source = temp;
				} else {
					temp = null;
				}

				var right_label = ec.DefineLabel ();
				ec.Emit (OpCodes.Brfalse_S, right_label);
				left.Emit (ec);
				ec.Emit (OpCodes.Br, end_label);
				ec.MarkLabel (right_label);

				if (temp != null)
					temp.Release (ec);
			} else {
				//
				// Common case where expression is not modified before null check and
				// we generate better/smaller code
				//
				left.Emit (ec);
				ec.Emit (OpCodes.Dup);

				// Only to make verifier happy
				if (left.Type.IsGenericParameter)
					ec.Emit (OpCodes.Box, left.Type);

				ec.Emit (OpCodes.Brtrue, end_label);

				ec.Emit (OpCodes.Pop);
			}

			right.Emit (ec);

			ec.MarkLabel (end_label);
		}