mcs/mcs/attribute.cs

   1 //\r
   2 // attribute.cs: Attribute Handler\r
   3 //\r
   4 // Author: Ravi Pratap (ravi@ximian.com)\r
   5 //\r
   6 // Licensed under the terms of the GNU GPL\r
   7 //\r
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)\r
   9 //\r
  10 //\r
  11 \r
  12 using System;\r
  13 using System.Collections;\r
  14 using System.Reflection;\r
  15 using System.Reflection.Emit;\r
  16 using System.Runtime.InteropServices;\r
  17 using System.Runtime.CompilerServices;\r
  18 using System.Text;\r
  19 \r
  20 namespace Mono.CSharp {\r
  21 \r
  22         public class Attribute {\r
  23                 public readonly string    Name;\r
  24                 public readonly ArrayList Arguments;\r
  25 \r
  26                 Location Location;\r
  27 \r
  28                 public Type Type;\r
  29                 \r
  30                 //\r
  31                 // The following are only meaningful when the attribute\r
  32                 // being emitted is one of the builtin ones\r
  33                 //\r
  34                 public AttributeTargets Targets;\r
  35                 public bool AllowMultiple;\r
  36                 public bool Inherited;\r
  37 \r
  38                 public bool UsageAttr = false;\r
  39                 \r
  40                 public MethodImplOptions ImplOptions;\r
  41                 public UnmanagedType     UnmanagedType;\r
  42                 \r
  43                 public Attribute (string name, ArrayList args, Location loc)\r
  44                 {\r
  45                         Name = name;\r
  46                         Arguments = args;\r
  47                         Location = loc;\r
  48                 }\r
  49 \r
  50                 void error617 (string name)\r
  51                 {\r
  52                         Report.Error (617, Location, "'" + name + "' is not a valid named attribute " +\r
  53                                       "argument. Named attribute arguments must be fields which are not " +\r
  54                                       "readonly, static or const, or properties with a set accessor which "+\r
  55                                       "are not static.");\r
  56                 }\r
  57 \r
  58                 void error182 ()\r
  59                 {\r
  60                         Report.Error (182, Location,\r
  61                                       "An attribute argument must be a constant expression, typeof " +\r
  62                                       "expression or array creation expression");\r
  63                 }\r
  64 \r
  65                 public CustomAttributeBuilder Resolve (EmitContext ec)\r
  66                 {\r
  67                         string name = Name;\r
  68                         bool MethodImplAttr = false;\r
  69                         bool MarshalAsAttr = false;\r
  70 \r
  71                         UsageAttr = false;\r
  72 \r
  73                         if (Name.IndexOf ("Attribute") == -1)\r
  74                                 name = Name + "Attribute";\r
  75                         else if (Name.LastIndexOf ("Attribute") == 0)\r
  76                                 name = Name + "Attribute";\r
  77 \r
  78                         Type = RootContext.LookupType (ec.DeclSpace, name, false, Location);\r
  79 \r
  80                         if (Type == null) {\r
  81                                 Report.Error (\r
  82                                         246, Location, "Could not find attribute '" + Name + "' (are you" +\r
  83                                         " missing a using directive or an assembly reference ?)");\r
  84                                 return null;\r
  85                         }\r
  86 \r
  87                         if (Type == TypeManager.attribute_usage_type)\r
  88                                 UsageAttr = true;\r
  89                         if (Type == TypeManager.methodimpl_attr_type)\r
  90                                 MethodImplAttr = true;\r
  91                         if (Type == TypeManager.marshal_as_attr_type)\r
  92                                 MarshalAsAttr = true;\r
  93                         \r
  94 \r
  95                         // Now we extract the positional and named arguments\r
  96                         \r
  97                         ArrayList pos_args = new ArrayList ();\r
  98                         ArrayList named_args = new ArrayList ();\r
  99                         \r
 100                         if (Arguments != null) {\r
 101                                 pos_args = (ArrayList) Arguments [0];\r
 102                                 if (Arguments.Count > 1)\r
 103                                         named_args = (ArrayList) Arguments [1];\r
 104                         }\r
 105                                 \r
 106                         object [] pos_values = new object [pos_args.Count];\r
 107 \r
 108                         //\r
 109                         // First process positional arguments \r
 110                         //\r
 111                         \r
 112                         int i;\r
 113                         for (i = 0; i < pos_args.Count; i++) {\r
 114                                 Argument a = (Argument) pos_args [i];\r
 115                                 Expression e;\r
 116 \r
 117                                 if (!a.Resolve (ec, Location))\r
 118                                         return null;\r
 119 \r
 120                                 e = a.Expr;\r
 121                                 if (e is Constant) {\r
 122                                         pos_values [i] = ((Constant) e).GetValue ();\r
 123                                 } else if (e is TypeOf) {\r
 124                                         pos_values [i] = ((TypeOf) e).TypeArg;\r
 125                                 } else {\r
 126                                         error182 ();\r
 127                                         return null;\r
 128                                 }\r
 129                                 \r
 130                                 if (UsageAttr)\r
 131                                         this.Targets = (AttributeTargets) pos_values [0];\r
 132                                 \r
 133                                 if (MethodImplAttr)\r
 134                                         this.ImplOptions = (MethodImplOptions) pos_values [0];\r
 135                                 \r
 136                                 if (MarshalAsAttr)\r
 137                                         this.UnmanagedType =\r
 138                                         (System.Runtime.InteropServices.UnmanagedType) pos_values [0];\r
 139                         }\r
 140 \r
 141                         //\r
 142                         // Now process named arguments\r
 143                         //\r
 144 \r
 145                         ArrayList field_infos = new ArrayList ();\r
 146                         ArrayList prop_infos  = new ArrayList ();\r
 147                         ArrayList field_values = new ArrayList ();\r
 148                         ArrayList prop_values = new ArrayList ();\r
 149                         \r
 150                         for (i = 0; i < named_args.Count; i++) {\r
 151                                 DictionaryEntry de = (DictionaryEntry) named_args [i];\r
 152                                 string member_name = (string) de.Key;\r
 153                                 Argument a  = (Argument) de.Value;\r
 154                                 Expression e;\r
 155                                 \r
 156                                 if (!a.Resolve (ec, Location))\r
 157                                         return null;\r
 158 \r
 159                                 Expression member = Expression.MemberLookup (\r
 160                                         ec, Type, member_name,\r
 161                                         MemberTypes.Field | MemberTypes.Property,\r
 162                                         BindingFlags.Public | BindingFlags.Instance,\r
 163                                         Location);\r
 164 \r
 165                                 if (member == null || !(member is PropertyExpr || member is FieldExpr)) {\r
 166                                         error617 (member_name);\r
 167                                         return null;\r
 168                                 }\r
 169 \r
 170                                 e = a.Expr;\r
 171                                 if (member is PropertyExpr) {\r
 172                                         PropertyExpr pe = (PropertyExpr) member;\r
 173                                         PropertyInfo pi = pe.PropertyInfo;\r
 174 \r
 175                                         if (!pi.CanWrite) {\r
 176                                                 error617 (member_name);\r
 177                                                 return null;\r
 178                                         }\r
 179 \r
 180                                         if (e is Constant) {\r
 181                                                 object o = ((Constant) e).GetValue ();\r
 182                                                 prop_values.Add (o);\r
 183                                                 \r
 184                                                 if (UsageAttr) {\r
 185                                                         if (member_name == "AllowMultiple")\r
 186                                                                 this.AllowMultiple = (bool) o;\r
 187                                                         if (member_name == "Inherited")\r
 188                                                                 this.Inherited = (bool) o;\r
 189                                                 }\r
 190                                                 \r
 191                                         } else { \r
 192                                                 error182 ();\r
 193                                                 return null;\r
 194                                         }\r
 195                                         \r
 196                                         prop_infos.Add (pi);\r
 197                                         \r
 198                                 } else if (member is FieldExpr) {\r
 199                                         FieldExpr fe = (FieldExpr) member;\r
 200                                         FieldInfo fi = fe.FieldInfo;\r
 201 \r
 202                                         if (fi.IsInitOnly) {\r
 203                                                 error617 (member_name);\r
 204                                                 return null;\r
 205                                         }\r
 206 \r
 207                                         if (e is Constant)\r
 208                                                 field_values.Add (((Constant) e).GetValue ());\r
 209                                         else { \r
 210                                                 error182 ();\r
 211                                                 return null;\r
 212                                         }\r
 213                                         \r
 214                                         field_infos.Add (fi);\r
 215                                 }\r
 216                         }\r
 217                         \r
 218                         Expression mg = Expression.MemberLookup (\r
 219                                 ec, Type, ".ctor", MemberTypes.Constructor,\r
 220                                 BindingFlags.Public | BindingFlags.Instance, Location);\r
 221 \r
 222                         if (mg == null) {\r
 223                                 Report.Error (\r
 224                                         -6, Location,\r
 225                                         "Could not find a constructor for this argument list.");\r
 226                                 return null;\r
 227                         }\r
 228 \r
 229                         MethodBase constructor = Invocation.OverloadResolve (\r
 230                                 ec, (MethodGroupExpr) mg, pos_args, Location);\r
 231 \r
 232                         if (constructor == null) {\r
 233                                 Report.Error (\r
 234                                         -6, Location,\r
 235                                         "Could not find a constructor for this argument list.");\r
 236                                 return null;\r
 237                         }\r
 238                         \r
 239                         PropertyInfo [] prop_info_arr = new PropertyInfo [prop_infos.Count];\r
 240                         FieldInfo [] field_info_arr = new FieldInfo [field_infos.Count];\r
 241                         object [] field_values_arr = new object [field_values.Count];\r
 242                         object [] prop_values_arr = new object [prop_values.Count];\r
 243 \r
 244                         field_infos.CopyTo  (field_info_arr, 0);\r
 245                         field_values.CopyTo (field_values_arr, 0);\r
 246 \r
 247                         prop_values.CopyTo  (prop_values_arr, 0);\r
 248                         prop_infos.CopyTo   (prop_info_arr, 0);\r
 249                         \r
 250                         CustomAttributeBuilder cb = new CustomAttributeBuilder (\r
 251                                 (ConstructorInfo) constructor, pos_values,\r
 252                                 prop_info_arr, prop_values_arr,\r
 253                                 field_info_arr, field_values_arr); \r
 254                         \r
 255                         return cb;\r
 256                 }\r
 257 \r
 258                 static string GetValidPlaces (Attribute attr)\r
 259                 {\r
 260                         StringBuilder sb = new StringBuilder ();\r
 261                         AttributeTargets targets = 0;\r
 262                         \r
 263                         TypeContainer a = TypeManager.LookupAttr (attr.Type);\r
 264 \r
 265                         if (a == null) {\r
 266                                 \r
 267                                 System.Attribute [] attrs = null;\r
 268                                 \r
 269                                 try {\r
 270                                         attrs = System.Attribute.GetCustomAttributes (attr.Type);\r
 271                                         \r
 272                                 } catch {\r
 273                                         Report.Error (-20, attr.Location, "Cannot find attribute type " + attr.Name +\r
 274                                                       " (maybe you forgot to set the usage using the" +\r
 275                                                       " AttributeUsage attribute ?).");\r
 276                                         return null;\r
 277                                 }\r
 278                                         \r
 279                                 foreach (System.Attribute tmp in attrs)\r
 280                                         if (tmp is AttributeUsageAttribute) \r
 281                                                 targets = ((AttributeUsageAttribute) tmp).ValidOn;\r
 282                         } else\r
 283                                 targets = a.Targets;\r
 284 \r
 285                         \r
 286                         if ((targets & AttributeTargets.Assembly) != 0)\r
 287                                 sb.Append ("'assembly' ");\r
 288 \r
 289                         if ((targets & AttributeTargets.Class) != 0)\r
 290                                 sb.Append ("'class' ");\r
 291 \r
 292                         if ((targets & AttributeTargets.Constructor) != 0)\r
 293                                 sb.Append ("'constructor' ");\r
 294 \r
 295                         if ((targets & AttributeTargets.Delegate) != 0)\r
 296                                 sb.Append ("'delegate' ");\r
 297 \r
 298                         if ((targets & AttributeTargets.Enum) != 0)\r
 299                                 sb.Append ("'enum' ");\r
 300 \r
 301                         if ((targets & AttributeTargets.Event) != 0)\r
 302                                 sb.Append ("'event' ");\r
 303 \r
 304                         if ((targets & AttributeTargets.Field) != 0)\r
 305                                 sb.Append ("'field' ");\r
 306 \r
 307                         if ((targets & AttributeTargets.Interface) != 0)\r
 308                                 sb.Append ("'interface' ");\r
 309 \r
 310                         if ((targets & AttributeTargets.Method) != 0)\r
 311                                 sb.Append ("'method' ");\r
 312 \r
 313                         if ((targets & AttributeTargets.Module) != 0)\r
 314                                 sb.Append ("'module' ");\r
 315 \r
 316                         if ((targets & AttributeTargets.Parameter) != 0)\r
 317                                 sb.Append ("'parameter' ");\r
 318 \r
 319                         if ((targets & AttributeTargets.Property) != 0)\r
 320                                 sb.Append ("'property' ");\r
 321 \r
 322                         if ((targets & AttributeTargets.ReturnValue) != 0)\r
 323                                 sb.Append ("'return value' ");\r
 324 \r
 325                         if ((targets & AttributeTargets.Struct) != 0)\r
 326                                 sb.Append ("'struct' ");\r
 327 \r
 328                         return sb.ToString ();\r
 329 \r
 330                 }\r
 331 \r
 332                 public static void error592 (Attribute a, Location loc)\r
 333                 {\r
 334                         Report.Error (\r
 335                                 592, loc, "Attribute '" + a.Name +\r
 336                                 "' is not valid on this declaration type. " +\r
 337                                 "It is valid on " + GetValidPlaces (a) + "declarations only.");\r
 338                 }\r
 339 \r
 340                 public static bool CheckAttribute (Attribute a, object element)\r
 341                 {\r
 342                         TypeContainer attr = TypeManager.LookupAttr (a.Type);\r
 343                         AttributeTargets targets = 0;\r
 344 \r
 345                         \r
 346                         if (attr == null) {\r
 347 \r
 348                                 System.Attribute [] attrs = null;\r
 349                                 \r
 350                                 try {\r
 351                                         attrs = System.Attribute.GetCustomAttributes (a.Type);\r
 352 \r
 353                                 } catch {\r
 354                                         Report.Error (-20, a.Location, "Cannot find attribute type " + a.Name +\r
 355                                                       " (maybe you forgot to set the usage using the" +\r
 356                                                       " AttributeUsage attribute ?).");\r
 357                                         return false;\r
 358                                 }\r
 359                                         \r
 360                                 foreach (System.Attribute tmp in attrs)\r
 361                                         if (tmp is AttributeUsageAttribute) \r
 362                                                 targets = ((AttributeUsageAttribute) tmp).ValidOn;\r
 363                         } else\r
 364                                 targets = attr.Targets;\r
 365 \r
 366                         if (element is Class) {\r
 367                                 if ((targets & AttributeTargets.Class) != 0)\r
 368                                         return true;\r
 369                                 else\r
 370                                         return false;\r
 371                                 \r
 372                         } else if (element is Struct) {\r
 373                                 if ((targets & AttributeTargets.Struct) != 0)\r
 374                                         return true;\r
 375                                 else\r
 376                                         return false;\r
 377                         } else if (element is Constructor) {\r
 378                                 if ((targets & AttributeTargets.Constructor) != 0)\r
 379                                         return true;\r
 380                                 else\r
 381                                         return false;\r
 382                         } else if (element is Delegate) {\r
 383                                 if ((targets & AttributeTargets.Delegate) != 0)\r
 384                                         return true;\r
 385                                 else\r
 386                                         return false;\r
 387                         } else if (element is Enum) {\r
 388                                 if ((targets & AttributeTargets.Enum) != 0)\r
 389                                         return true;\r
 390                                 else\r
 391                                         return false;\r
 392                         } else if (element is Event) {\r
 393                                 if ((targets & AttributeTargets.Event) != 0)\r
 394                                         return true;\r
 395                                 else\r
 396                                         return false;\r
 397                         } else if (element is Field) {\r
 398                                 if ((targets & AttributeTargets.Field) != 0)\r
 399                                         return true;\r
 400                                 else\r
 401                                         return false;\r
 402                         } else if (element is Interface) {\r
 403                                 if ((targets & AttributeTargets.Interface) != 0)\r
 404                                         return true;\r
 405                                 else\r
 406                                         return false;\r
 407                         } else if (element is Method || element is Operator) {\r
 408                                 if ((targets & AttributeTargets.Method) != 0)\r
 409                                         return true;\r
 410                                 else\r
 411                                         return false;\r
 412                         } else if (element is ParameterBuilder) {\r
 413                                 if ((targets & AttributeTargets.Parameter) != 0)\r
 414                                         return true;\r
 415                                 else\r
 416                                         return false;\r
 417                         } else if (element is Property) {\r
 418                                 if ((targets & AttributeTargets.Property) != 0)\r
 419                                         return true;\r
 420                                 else\r
 421                                         return false;\r
 422                         } else if (element is AssemblyBuilder){\r
 423                                 if ((targets & AttributeTargets.Assembly) != 0)\r
 424                                         return true;\r
 425                                 else\r
 426                                         return false;\r
 427                         }\r
 428 \r
 429                         return false;\r
 430                 }\r
 431                 \r
 432                 public static void ApplyAttributes (EmitContext ec, object builder, object kind,\r
 433                                                     Attributes opt_attrs, Location loc)\r
 434                 {\r
 435                         if (opt_attrs == null)\r
 436                                 return;\r
 437 \r
 438                         if (opt_attrs.AttributeSections == null)\r
 439                                 return;\r
 440 \r
 441                         foreach (AttributeSection asec in opt_attrs.AttributeSections) {\r
 442 \r
 443                                 if (asec.Attributes == null)\r
 444                                         continue;\r
 445 \r
 446                                 if (asec.Target == "assembly" && !(builder is AssemblyBuilder))\r
 447                                         continue;\r
 448                                 \r
 449                                 foreach (Attribute a in asec.Attributes) {\r
 450                                         CustomAttributeBuilder cb = a.Resolve (ec);\r
 451 \r
 452                                         if (cb == null)\r
 453                                                 continue;\r
 454 \r
 455                                         if (!(kind is TypeContainer))\r
 456                                                 if (!CheckAttribute (a, kind)) {\r
 457                                                         error592 (a, loc);\r
 458                                                         return;\r
 459                                                 }\r
 460 \r
 461                                         if (kind is Method || kind is Operator) {\r
 462 \r
 463                                                 if (a.Type == TypeManager.methodimpl_attr_type) {\r
 464                                                         if (a.ImplOptions == MethodImplOptions.InternalCall)\r
 465                                                                 ((MethodBuilder) builder).SetImplementationFlags (\r
 466                                                                            MethodImplAttributes.InternalCall |\r
 467                                                                            MethodImplAttributes.Runtime);\r
 468                                                 } else if (a.Type != TypeManager.dllimport_type)\r
 469                                                         ((MethodBuilder) builder).SetCustomAttribute (cb);\r
 470 \r
 471                                         } else if (kind is Constructor) {\r
 472                                                 ((ConstructorBuilder) builder).SetCustomAttribute (cb);\r
 473                                         } else if (kind is Field) {\r
 474                                                 ((FieldBuilder) builder).SetCustomAttribute (cb);\r
 475                                         } else if (kind is Property || kind is Indexer) {\r
 476                                                 ((PropertyBuilder) builder).SetCustomAttribute (cb);\r
 477                                         } else if (kind is Event) {\r
 478                                                 ((EventBuilder) builder).SetCustomAttribute (cb);\r
 479                                         } else if (kind is ParameterBuilder) {\r
 480 \r
 481                                                 if (a.Type == TypeManager.marshal_as_attr_type) {\r
 482                                                         UnmanagedMarshal marshal =\r
 483                                                                 UnmanagedMarshal.DefineUnmanagedMarshal (a.UnmanagedType);\r
 484                                                         \r
 485                                                         ((ParameterBuilder) builder).SetMarshal (marshal);\r
 486                                                 } else \r
 487                                                         ((ParameterBuilder) builder).SetCustomAttribute (cb);\r
 488                                                 \r
 489                                         } else if (kind is Enum) {\r
 490                                                 ((TypeBuilder) builder).SetCustomAttribute (cb); \r
 491 \r
 492                                         } else if (kind is TypeContainer) {\r
 493                                                 TypeContainer tc = (TypeContainer) kind;\r
 494                                                 \r
 495                                                 if (a.UsageAttr) {\r
 496                                                         tc.Targets = a.Targets;\r
 497                                                         tc.AllowMultiple = a.AllowMultiple;\r
 498                                                         tc.Inherited = a.Inherited;\r
 499                                                         \r
 500                                                 } else if (a.Type == TypeManager.default_member_type) {\r
 501                                                         if (tc.Indexers != null) {\r
 502                                                                 Report.Error (646, loc,\r
 503                                                                       "Cannot specify the DefaultMember attribute on" +\r
 504                                                                       " a type containing an indexer");\r
 505                                                                 return;\r
 506                                                         }\r
 507 \r
 508                                                 } else {\r
 509                                                         if (!CheckAttribute (a, kind)) {\r
 510                                                                 error592 (a, loc);\r
 511                                                                 return;\r
 512                                                         }\r
 513                                                 }\r
 514                                                 \r
 515                                                 ((TypeBuilder) builder).SetCustomAttribute (cb);\r
 516                                                 \r
 517                                         } else if (kind is AssemblyBuilder){\r
 518                                                 ((AssemblyBuilder) builder).SetCustomAttribute (cb);\r
 519                                         } else if (kind is ModuleBuilder) {\r
 520                                                 ((ModuleBuilder) builder).SetCustomAttribute (cb);\r
 521                                         } else\r
 522                                                 throw new Exception ("Unknown kind: " + kind);\r
 523                                 }\r
 524                         }\r
 525                 }\r
 526 \r
 527                 public MethodBuilder DefinePInvokeMethod (EmitContext ec, TypeBuilder builder, string name,\r
 528                                                           MethodAttributes flags, Type ret_type, Type [] param_types)\r
 529                 {\r
 530                         //\r
 531                         // We extract from the attribute the information we need \r
 532                         //\r
 533 \r
 534                         if (Arguments == null) {\r
 535                                 Console.WriteLine ("Internal error : this is not supposed to happen !");\r
 536                                 return null;\r
 537                         }\r
 538 \r
 539                         string attr_name = Name;\r
 540 \r
 541                         if (Name.IndexOf ("Attribute") == -1)\r
 542                                 attr_name = Name + "Attribute";\r
 543                         else if (Name.LastIndexOf ("Attribute") == 0)\r
 544                                 attr_name = Name + "Attribute";\r
 545                         \r
 546                         Type = RootContext.LookupType (ec.DeclSpace, attr_name, false, Location);\r
 547 \r
 548                         if (Type == null) {\r
 549                                 Report.Error (246, Location, "Could not find attribute '" + Name + "' (are you" +\r
 550                                               " missing a using directive or an assembly reference ?)");\r
 551                                 return null;\r
 552                         }\r
 553                         \r
 554                         ArrayList named_args = new ArrayList ();\r
 555                         \r
 556                         ArrayList pos_args = (ArrayList) Arguments [0];\r
 557                         if (Arguments.Count > 1)\r
 558                                 named_args = (ArrayList) Arguments [1];\r
 559                         \r
 560 \r
 561                         string dll_name = null;\r
 562                         \r
 563                         Argument tmp = (Argument) pos_args [0];\r
 564 \r
 565                         if (!tmp.Resolve (ec, Location))\r
 566                                 return null;\r
 567                         \r
 568                         if (tmp.Expr is Constant)\r
 569                                 dll_name = (string) ((Constant) tmp.Expr).GetValue ();\r
 570                         else { \r
 571                                 error182 ();\r
 572                                 return null;\r
 573                         }\r
 574 \r
 575                         // Now we process the named arguments\r
 576                         CallingConvention cc = CallingConvention.Winapi;\r
 577                         CharSet charset = CharSet.Ansi;\r
 578                         bool preserve_sig = true;\r
 579                         bool exact_spelling = false;\r
 580                         bool set_last_err = false;\r
 581                         string entry_point = null;\r
 582 \r
 583                         for (int i = 0; i < named_args.Count; i++) {\r
 584 \r
 585                                 DictionaryEntry de = (DictionaryEntry) named_args [i];\r
 586 \r
 587                                 string member_name = (string) de.Key;\r
 588                                 Argument a  = (Argument) de.Value;\r
 589 \r
 590                                 if (!a.Resolve (ec, Location))\r
 591                                         return null;\r
 592 \r
 593                                 Expression member = Expression.MemberLookup (\r
 594                                         ec, Type, member_name, \r
 595                                         MemberTypes.Field | MemberTypes.Property,\r
 596                                         BindingFlags.Public | BindingFlags.Instance,\r
 597                                         Location);\r
 598 \r
 599                                 if (member == null || !(member is FieldExpr)) {\r
 600                                         error617 (member_name);\r
 601                                         return null;\r
 602                                 }\r
 603 \r
 604                                 if (member is FieldExpr) {\r
 605                                         FieldExpr fe = (FieldExpr) member;\r
 606                                         FieldInfo fi = fe.FieldInfo;\r
 607 \r
 608                                         if (fi.IsInitOnly) {\r
 609                                                 error617 (member_name);\r
 610                                                 return null;\r
 611                                         }\r
 612 \r
 613                                         if (a.Expr is Constant) {\r
 614                                                 Constant c = (Constant) a.Expr;\r
 615                                                 \r
 616                                                 if (member_name == "CallingConvention")\r
 617                                                         cc = (CallingConvention) c.GetValue ();\r
 618                                                 else if (member_name == "CharSet")\r
 619                                                         charset = (CharSet) c.GetValue ();\r
 620                                                 else if (member_name == "EntryPoint")\r
 621                                                         entry_point = (string) c.GetValue ();\r
 622                                                 else if (member_name == "SetLastError")\r
 623                                                         set_last_err = (bool) c.GetValue ();\r
 624                                                 else if (member_name == "ExactSpelling")\r
 625                                                         exact_spelling = (bool) c.GetValue ();\r
 626                                                 else if (member_name == "PreserveSig")\r
 627                                                         preserve_sig = (bool) c.GetValue ();\r
 628                                         } else { \r
 629                                                 error182 ();\r
 630                                                 return null;\r
 631                                         }\r
 632                                         \r
 633                                 }\r
 634                         }\r
 635 \r
 636                         MethodBuilder mb = builder.DefinePInvokeMethod (\r
 637                                 name, dll_name, flags | MethodAttributes.HideBySig,\r
 638                                 CallingConventions.Standard,\r
 639                                 ret_type,\r
 640                                 param_types,\r
 641                                 cc,\r
 642                                 charset);\r
 643 \r
 644                         if (preserve_sig)\r
 645                                 mb.SetImplementationFlags (MethodImplAttributes.PreserveSig);\r
 646                         \r
 647                         return mb;\r
 648                 }\r
 649                 \r
 650         }\r
 651         \r
 652         public class AttributeSection {\r
 653                 \r
 654                 public readonly string    Target;\r
 655                 public readonly ArrayList Attributes;\r
 656                 \r
 657                 public AttributeSection (string target, ArrayList attrs)\r
 658                 {\r
 659                         Target = target;\r
 660                         Attributes = attrs;\r
 661                 }\r
 662                 \r
 663         }\r
 664 \r
 665         public class Attributes {\r
 666                 public ArrayList AttributeSections;\r
 667                 public Location Location;\r
 668 \r
 669                 public Attributes (AttributeSection a, Location loc)\r
 670                 {\r
 671                         AttributeSections = new ArrayList ();\r
 672                         AttributeSections.Add (a);\r
 673 \r
 674                 }\r
 675 \r
 676                 public void AddAttribute (AttributeSection a)\r
 677                 {\r
 678                         if (a != null)\r
 679                                 AttributeSections.Add (a);\r
 680                 }\r
 681         }\r
 682 }\r