mcs/mbas/argument.cs

   1 //
   2 // argument.cs: Arguments representation for the IL tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001 Ximian, Inc.
   8 //
   9 //
  10 #define USE_OLD
  11
  12 namespace Mono.MonoBASIC {
  13         using System;
  14         using System.Collections;
  15         using System.Reflection;
  16         using System.Reflection.Emit;
  17         using System.Text;
  18
  19
  20         /// <summary>
  21         ///   Used for arguments to New(), Invocation()
  22         /// </summary>
  23         public class Argument {
  24                 public enum AType : byte {
  25                         Expression,
  26                         Ref,
  27                         Out,
  28                         NoArg,
  29                         AddressOf
  30                 };
  31
  32                 public AType ArgType;
  33                 public Expression Expr;
  34
  35                 public Argument (Expression expr, AType type)
  36                 {
  37                         this.Expr = expr;
  38                         this.ArgType = type;
  39                 }
  40
  41                 public Type Type {
  42                         get {
  43                                 if (ArgType == AType.Ref || ArgType == AType.Out)
  44                                         return TypeManager.LookupType (Expr.Type.ToString () + "&");
  45                                 else
  46                                         return Expr.Type;
  47                         }
  48                 }
  49
  50                 public Parameter.Modifier GetParameterModifier ()
  51                 {
  52                         switch (ArgType) {
  53                         case AType.Out:
  54                                 return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
  55
  56                         case AType.Ref:
  57                                 return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
  58
  59                         default:
  60                                 return Parameter.Modifier.NONE;
  61                         }
  62                 }
  63
  64                 public static string FullDesc (Argument a)
  65                 {
  66                         return (a.ArgType == AType.Ref ? "ref " :
  67                                 (a.ArgType == AType.Out ? "out " : "")) +
  68                                 TypeManager.MonoBASIC_Name (a.Expr.Type);
  69                 }
  70
  71                 public bool ResolveMethodGroup (EmitContext ec, Location loc)
  72                 {
  73                         // FIXME: csc doesn't report any error if you try to use `ref' or
  74                         //        `out' in a delegate creation expression.
  75                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
  76                         if (Expr == null)
  77                                 return false;
  78
  79                         return true;
  80                 }
  81
  82                 public bool Resolve (EmitContext ec, Location loc)
  83                 {
  84                         // Optional void arguments - MyCall (1,,2) - are resolved later
  85                         // in VerifyArgsCompat
  86                         if (ArgType == AType.NoArg || ArgType == AType.Ref)
  87                         {
  88                                 return true;
  89                         }
  90
  91 /*
  92                         if (ArgType == AType.Ref) {
  93                                 Expr = Expr.Resolve (ec);
  94                                 if (Expr == null)
  95                                         return false;
  96
  97                                 Expr = Expr.ResolveLValue (ec, Expr);
  98                         } else */
  99
 100                         if (ArgType == AType.Out)
 101                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
 102                         else if (ArgType == AType.AddressOf) {
 103                                 Expression temp_expr = Expr;
 104
 105                                 if (temp_expr is SimpleName) {
 106                                         SimpleName sn = temp_expr as SimpleName;
 107                                         temp_expr = sn.DoResolveAllowStatic(ec);
 108                                 }
 109                                 else if (temp_expr is MemberAccess)     {
 110                                         MemberAccess ma = temp_expr as MemberAccess;
 111                                         temp_expr = ma.DoResolve(ec);
 112                                 }
 113
 114                                 if (temp_expr is MethodGroupExpr)
 115                                         return true;
 116
 117                                 ArgType = AType.Expression;
 118                                 Expr = Expr.Resolve (ec);
 119                         }
 120                         else
 121                                 Expr = Expr.Resolve (ec);
 122
 123                         if (Expr == null)
 124                                 return false;
 125
 126                         if (ArgType == AType.Expression)
 127                                 return true;
 128
 129                         if (Expr.eclass != ExprClass.Variable){
 130                                 //
 131                                 // We just probe to match the CSC output
 132                                 //
 133                                 if (Expr.eclass == ExprClass.PropertyAccess ||
 134                                     Expr.eclass == ExprClass.IndexerAccess){
 135                                         Report.Error (
 136                                                 206, loc,
 137                                                 "A property or indexer can not be passed as an out or ref " +
 138                                                 "parameter");
 139                                 } else {
 140                                         Report.Error (
 141                                                 1510, loc,
 142                                                 "An lvalue is required as an argument to out or ref");
 143                                 }
 144                                 return false;
 145                         }
 146
 147                         return true;
 148                 }
 149
 150                 public void Emit (EmitContext ec)
 151                 {
 152                         //
 153                         // Ref and Out parameters need to have their addresses taken.
 154                         //
 155                         // ParameterReferences might already be references, so we want
 156                         // to pass just the value
 157                         //
 158                         if (ArgType == AType.Ref || ArgType == AType.Out){
 159                                 AddressOp mode = AddressOp.Store;
 160
 161                                 if (ArgType == AType.Ref)
 162                                         mode |= AddressOp.Load;
 163
 164                                 if (Expr is ParameterReference){
 165                                         ParameterReference pr = (ParameterReference) Expr;
 166
 167                                         if (pr.is_ref)
 168                                                 pr.EmitLoad (ec);
 169                                         else {
 170
 171                                                 pr.AddressOf (ec, mode);
 172                                         }
 173                                 } else
 174                                         ((IMemoryLocation)Expr).AddressOf (ec, mode);
 175                         } else
 176                                 Expr.Emit (ec);
 177                 }
 178         }
 179 }