mcs/mcs/parameter.cs

   1 //
   2 // parameter.cs: Parameter definition.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //         Marek Safar (marek.safar@seznam.cz)
   6 //
   7 // Dual licensed under the terms of the MIT X11 or GNU GPL
   8 //
   9 // Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
  10 // Copyright 2003-2008 Novell, Inc.
  11 //
  12 //
  13 using System;
  14 using System.Reflection;
  15 using System.Reflection.Emit;
  16 using System.Collections;
  17 using System.Text;
  18
  19 namespace Mono.CSharp {
  20
  21         /// <summary>
  22         ///   Abstract Base class for parameters of a method.
  23         /// </summary>
  24         public abstract class ParameterBase : Attributable {
  25
  26                 protected ParameterBuilder builder;
  27
  28                 protected ParameterBase (Attributes attrs)
  29                         : base (attrs)
  30                 {
  31                 }
  32
  33                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa)
  34                 {
  35 #if !NET_2_0
  36                         if (a.Type == pa.MarshalAs) {
  37                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  38                                 if (marshal != null) {
  39                                         builder.SetMarshal (marshal);
  40                                 }
  41                                 return;
  42                         }
  43 #endif
  44                         if (a.HasSecurityAttribute) {
  45                                 a.Error_InvalidSecurityParent ();
  46                                 return;
  47                         }
  48
  49                         builder.SetCustomAttribute (cb);
  50                 }
  51
  52                 public override bool IsClsComplianceRequired()
  53                 {
  54                         return false;
  55                 }
  56         }
  57
  58         /// <summary>
  59         /// Class for applying custom attributes on the return type
  60         /// </summary>
  61         public class ReturnParameter : ParameterBase {
  62                 public ReturnParameter (MethodBuilder mb, Location location):
  63                         base (null)
  64                 {
  65                         try {
  66                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  67                         }
  68                         catch (ArgumentOutOfRangeException) {
  69                                 Report.RuntimeMissingSupport (location, "custom attributes on the return type");
  70                         }
  71                 }
  72
  73                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa)
  74                 {
  75                         if (a.Type == pa.CLSCompliant) {
  76                                 Report.Warning (3023, 1, a.Location, "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  77                         }
  78
  79                         // This occurs after Warning -28
  80                         if (builder == null)
  81                                 return;
  82
  83                         base.ApplyAttributeBuilder (a, cb, pa);
  84                 }
  85
  86                 public override AttributeTargets AttributeTargets {
  87                         get {
  88                                 return AttributeTargets.ReturnValue;
  89                         }
  90                 }
  91
  92                 public override IResolveContext ResolveContext {
  93                         get {
  94                                 throw new NotSupportedException ();
  95                         }
  96                 }
  97
  98                 /// <summary>
  99                 /// Is never called
 100                 /// </summary>
 101                 public override string[] ValidAttributeTargets {
 102                         get {
 103                                 return null;
 104                         }
 105                 }
 106         }
 107
 108         /// <summary>
 109         /// Class for applying custom attributes on the implicit parameter type
 110         /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
 111         /// </summary>
 112         ///
 113         // TODO: should use more code from Parameter.ApplyAttributeBuilder
 114         public class ImplicitParameter : ParameterBase {
 115                 public ImplicitParameter (MethodBuilder mb):
 116                         base (null)
 117                 {
 118                         builder = mb.DefineParameter (1, ParameterAttributes.None, "value");
 119                 }
 120
 121                 public override AttributeTargets AttributeTargets {
 122                         get {
 123                                 return AttributeTargets.Parameter;
 124                         }
 125                 }
 126
 127                 public override IResolveContext ResolveContext {
 128                         get {
 129                                 throw new NotSupportedException ();
 130                         }
 131                 }
 132
 133                 /// <summary>
 134                 /// Is never called
 135                 /// </summary>
 136                 public override string[] ValidAttributeTargets {
 137                         get {
 138                                 return null;
 139                         }
 140                 }
 141         }
 142
 143         public class ImplicitLambdaParameter : Parameter
 144         {
 145                 public ImplicitLambdaParameter (string name, Location loc)
 146                         : base (null, name, Modifier.NONE, null, loc)
 147                 {
 148                 }
 149
 150                 public override Type Resolve (IResolveContext ec)
 151                 {
 152                         if (parameter_type == null)
 153                                 throw new InternalErrorException ("A type of implicit lambda parameter `{0}' is not set",
 154                                         Name);
 155
 156                         return parameter_type;
 157                 }
 158
 159                 public Type Type {
 160                         set { parameter_type = value; }
 161                 }
 162         }
 163
 164         public class ParamsParameter : Parameter {
 165                 public ParamsParameter (FullNamedExpression type, string name, Attributes attrs, Location loc):
 166                         base (type, name, Parameter.Modifier.PARAMS, attrs, loc)
 167                 {
 168                 }
 169
 170                 public override Type Resolve (IResolveContext ec)
 171                 {
 172                         if (base.Resolve (ec) == null)
 173                                 return null;
 174
 175                         if (!parameter_type.IsArray || parameter_type.GetArrayRank () != 1) {
 176                                 Report.Error (225, Location, "The params parameter must be a single dimensional array");
 177                                 return null;
 178                         }
 179
 180                         return parameter_type;
 181                 }
 182
 183                 public override void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 184                 {
 185                         base.ApplyAttributes (mb, cb, index);
 186                         PredefinedAttributes.Get.ParamArray.EmitAttribute (builder, Location);
 187                 }
 188         }
 189
 190         public class ArglistParameter : Parameter {
 191                 // Doesn't have proper type because it's never chosen for better conversion
 192                 public ArglistParameter (Location loc) :
 193                         base (null, String.Empty, Parameter.Modifier.NONE, null, loc)
 194                 {
 195                 }
 196
 197                 public override void  ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 198                 {
 199                         // Nothing to do
 200                 }
 201
 202                 public override bool CheckAccessibility (InterfaceMemberBase member)
 203                 {
 204                         return true;
 205                 }
 206
 207                 public override Type Resolve (IResolveContext ec)
 208                 {
 209                         return typeof (ArglistAccess);
 210                 }
 211
 212                 public override string GetSignatureForError ()
 213                 {
 214                         return "__arglist";
 215                 }
 216         }
 217
 218         public interface IParameterData
 219         {
 220                 Expression DefaultValue { get; }
 221                 bool HasExtensionMethodModifier { get; }
 222                 bool HasDefaultValue { get; }
 223                 Parameter.Modifier ModFlags { get; }
 224                 string Name { get; }
 225         }
 226
 227         //
 228         // Parameter information created by parser
 229         //
 230         public class Parameter : ParameterBase, IParameterData, ILocalVariable {
 231                 [Flags]
 232                 public enum Modifier : byte {
 233                         NONE    = 0,
 234                         REF     = REFMASK | ISBYREF,
 235                         OUT     = OUTMASK | ISBYREF,
 236                         PARAMS  = 4,
 237                         // This is a flag which says that it's either REF or OUT.
 238                         ISBYREF = 8,
 239                         REFMASK = 32,
 240                         OUTMASK = 64,
 241                         This    = 128
 242                 }
 243
 244                 static string[] attribute_targets = new string [] { "param" };
 245
 246                 protected FullNamedExpression TypeName;
 247                 readonly Modifier modFlags;
 248                 string name;
 249                 Expression default_expr;
 250                 protected Type parameter_type;
 251                 public readonly Location Location;
 252                 int idx;
 253                 public bool HasAddressTaken;
 254
 255                 IResolveContext resolve_context;
 256                 LocalVariableReference expr_tree_variable;
 257                 static TypeExpr parameter_expr_tree_type;
 258
 259                 public HoistedVariable HoistedVariableReference;
 260
 261                 public Parameter (FullNamedExpression type, string name, Modifier mod, Attributes attrs, Location loc)
 262                         : base (attrs)
 263                 {
 264                         if (type == TypeManager.system_void_expr)
 265                                 Report.Error (1536, loc, "Invalid parameter type `void'");
 266
 267                         this.name = name;
 268                         modFlags = mod;
 269                         Location = loc;
 270                         TypeName = type;
 271                 }
 272
 273                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa)
 274                 {
 275                         if (a.Type == pa.In && ModFlags == Modifier.OUT) {
 276                                 Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
 277                                 return;
 278                         }
 279
 280                         if (a.Type == pa.ParamArray) {
 281                                 Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
 282                                 return;
 283                         }
 284
 285                         if (a.Type == PredefinedAttributes.Get.Out && (ModFlags & Modifier.REF) == Modifier.REF &&
 286                             !OptAttributes.Contains (pa.In)) {
 287                                 Report.Error (662, a.Location,
 288                                         "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
 289                                 return;
 290                         }
 291
 292                         if (a.Type == pa.CLSCompliant) {
 293                                 Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 294                         }
 295
 296                         if (HasDefaultValue && (a.Type == pa.DefaultParameterValue || a.Type == pa.OptionalParameter)) {
 297                                 Report.Error (1745, a.Location,
 298                                         "Cannot specify `{0}' attribute on optional parameter `{1}'",
 299                                         TypeManager.CSharpName (a.Type).Replace ("Attribute", ""), Name);
 300                                 return;
 301                         }
 302
 303                         if (a.Type == pa.DefaultParameterValue) {
 304                                 object val = a.GetParameterDefaultValue ();
 305                                 if (val != null) {
 306                                         Type t = val.GetType ();
 307                                         if (t.IsArray || TypeManager.IsSubclassOf (t, TypeManager.type_type)) {
 308                                                 if (parameter_type == TypeManager.object_type) {
 309                                                         if (!t.IsArray)
 310                                                                 t = TypeManager.type_type;
 311
 312                                                         Report.Error (1910, a.Location, "Argument of type `{0}' is not applicable for the DefaultParameterValue attribute",
 313                                                                 TypeManager.CSharpName (t));
 314                                                 } else {
 315                                                         Report.Error (1909, a.Location, "The DefaultParameterValue attribute is not applicable on parameters of type `{0}'",
 316                                                                 TypeManager.CSharpName (parameter_type)); ;
 317                                                 }
 318                                                 return;
 319                                         }
 320                                 }
 321
 322                                 if (parameter_type == TypeManager.object_type ||
 323                                     (val == null && !TypeManager.IsGenericParameter (parameter_type) && TypeManager.IsReferenceType (parameter_type)) ||
 324                                     (val != null && TypeManager.TypeToCoreType (val.GetType ()) == parameter_type))
 325                                         builder.SetConstant (val);
 326                                 else
 327                                         Report.Error (1908, a.Location, "The type of the default value should match the type of the parameter");
 328                                 return;
 329                         }
 330
 331                         base.ApplyAttributeBuilder (a, cb, pa);
 332                 }
 333
 334                 public virtual bool CheckAccessibility (InterfaceMemberBase member)
 335                 {
 336                         if (parameter_type == null || TypeManager.IsGenericParameter (parameter_type))
 337                                 return true;
 338
 339                         return member.IsAccessibleAs (parameter_type);
 340                 }
 341
 342                 public override IResolveContext ResolveContext {
 343                         get {
 344                                 return resolve_context;
 345                         }
 346                 }
 347
 348                 // <summary>
 349                 //   Resolve is used in method definitions
 350                 // </summary>
 351                 public virtual Type Resolve (IResolveContext rc)
 352                 {
 353                         // HACK: to resolve attributes correctly
 354                         this.resolve_context = rc;
 355
 356                         if (parameter_type != null)
 357                                 return parameter_type;
 358
 359                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (rc, false);
 360                         if (texpr == null)
 361                                 return null;
 362
 363                         parameter_type = texpr.Type;
 364
 365                         // Ignore all checks for dummy members
 366                         AbstractPropertyEventMethod pem = rc as AbstractPropertyEventMethod;
 367                         if (pem != null && pem.IsDummy)
 368                                 return parameter_type;
 369
 370                         if (default_expr != null) {
 371                                 EmitContext ec = new EmitContext (rc, rc.GenericDeclContainer, Location, null, parameter_type, 0);
 372                                 default_expr = default_expr.Resolve (ec);
 373                                 if (default_expr != null) {
 374                                         Constant value = default_expr as Constant;
 375                                         if (value == null) {
 376                                                 if (default_expr != null) {
 377                                                         bool is_valid = false;
 378                                                         if (default_expr is DefaultValueExpression) {
 379                                                                 is_valid = true;
 380                                                         } else if (default_expr is New && ((New) default_expr).IsDefaultValueType) {
 381                                                                 is_valid = TypeManager.IsEqual (parameter_type, default_expr.Type) ||
 382                                                                          (TypeManager.IsNullableType (parameter_type) &&
 383                                                                                 Convert.ImplicitNulableConversion (ec, default_expr, parameter_type) != EmptyExpression.Null);
 384                                                         } else {
 385                                                                 Report.Error (1736, default_expr.Location,
 386                                                                         "The expression being assigned to optional parameter `{0}' must be a constant or default value",
 387                                                                         Name);
 388                                                                 is_valid = true;
 389                                                         }
 390
 391                                                         if (!is_valid) {
 392                                                                 default_expr = null;
 393                                                                 Report.Error (1763, Location,
 394                                                                         "Optional parameter `{0}' of type `{1}' can only be initialized with `null'",
 395                                                                         Name, GetSignatureForError ());
 396                                                         }
 397                                                 }
 398                                         } else {
 399                                                 Constant c = value.ConvertImplicitly (parameter_type);
 400                                                 if (c == null) {
 401                                                         if (parameter_type == TypeManager.object_type) {
 402                                                                 Report.Error (1763, Location,
 403                                                                         "Optional parameter `{0}' of type `{1}' can only be initialized with `null'",
 404                                                                         Name, GetSignatureForError ());
 405                                                         } else {
 406                                                                 Report.Error (1750, Location,
 407                                                                         "Optional parameter value `{0}' cannot be converted to parameter type `{1}'",
 408                                                                         value.GetValue (), GetSignatureForError ());
 409                                                         }
 410                                                         default_expr = null;
 411                                                 }
 412                                         }
 413                                 }
 414                         }
 415
 416                         if ((modFlags & Parameter.Modifier.ISBYREF) != 0 &&
 417                                 TypeManager.IsSpecialType (parameter_type)) {
 418                                 Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
 419                                         GetSignatureForError ());
 420                                 return null;
 421                         }
 422
 423                         TypeManager.CheckTypeVariance (parameter_type,
 424                                 (modFlags & Parameter.Modifier.ISBYREF) != 0 ? Variance.None : Variance.Contravariant,
 425                                 rc as MemberCore);
 426
 427                         if (texpr is TypeParameterExpr)
 428                                 return parameter_type;
 429
 430                         if ((parameter_type.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute) {
 431                                 Report.Error (721, Location, "`{0}': static types cannot be used as parameters",
 432                                         texpr.GetSignatureForError ());
 433                                 return parameter_type;
 434                         }
 435
 436                         if ((modFlags & Modifier.This) != 0 && parameter_type.IsPointer) {
 437                                 Report.Error (1103, Location, "The type of extension method cannot be `{0}'",
 438                                         TypeManager.CSharpName (parameter_type));
 439                         }
 440
 441                         return parameter_type;
 442                 }
 443
 444                 public void ResolveVariable (int idx)
 445                 {
 446                         this.idx = idx;
 447                 }
 448
 449                 public bool HasDefaultValue {
 450                         get { return default_expr != null; }
 451                 }
 452
 453                 public bool HasExtensionMethodModifier {
 454                         get { return (modFlags & Modifier.This) != 0; }
 455                 }
 456
 457                 public Modifier ModFlags {
 458                         get { return modFlags & ~Modifier.This; }
 459                 }
 460
 461                 public string Name {
 462                         get { return name; }
 463                         set { name = value; }
 464                 }
 465
 466                 ParameterAttributes Attributes {
 467                         get { return ParametersCompiled.GetParameterAttribute (modFlags) |
 468                                 (HasDefaultValue ? ParameterAttributes.Optional : ParameterAttributes.None); }
 469                 }
 470
 471                 public override AttributeTargets AttributeTargets {
 472                         get {
 473                                 return AttributeTargets.Parameter;
 474                         }
 475                 }
 476
 477                 public virtual string GetSignatureForError ()
 478                 {
 479                         string type_name;
 480                         if (parameter_type != null)
 481                                 type_name = TypeManager.CSharpName (parameter_type);
 482                         else
 483                                 type_name = TypeName.GetSignatureForError ();
 484
 485                         string mod = GetModifierSignature (modFlags);
 486                         if (mod.Length > 0)
 487                                 return String.Concat (mod, " ", type_name);
 488
 489                         return type_name;
 490                 }
 491
 492                 public static string GetModifierSignature (Modifier mod)
 493                 {
 494                         switch (mod) {
 495                         case Modifier.OUT:
 496                                 return "out";
 497                         case Modifier.PARAMS:
 498                                 return "params";
 499                         case Modifier.REF:
 500                                 return "ref";
 501                         case Modifier.This:
 502                                 return "this";
 503                         default:
 504                                 return "";
 505                         }
 506                 }
 507
 508                 public void IsClsCompliant ()
 509                 {
 510                         if (AttributeTester.IsClsCompliant (parameter_type))
 511                                 return;
 512
 513                         Report.Warning (3001, 1, Location, "Argument type `{0}' is not CLS-compliant", GetSignatureForError ());
 514                 }
 515
 516                 public virtual void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index)
 517                 {
 518                         if (mb == null)
 519                                 builder = cb.DefineParameter (index, Attributes, Name);
 520                         else
 521                                 builder = mb.DefineParameter (index, Attributes, Name);
 522
 523                         if (OptAttributes != null)
 524                                 OptAttributes.Emit ();
 525
 526                         if (HasDefaultValue) {
 527                                 //
 528                                 // Emit constant values for true constants only, the other
 529                                 // constant-like expressions will rely on default value expression
 530                                 //
 531                                 Constant c = default_expr as Constant;
 532                                 if (c != null) {
 533                                         if (default_expr.Type == TypeManager.decimal_type) {
 534                                                 builder.SetCustomAttribute (Const.CreateDecimalConstantAttribute (c));
 535                                         } else {
 536                                                 builder.SetConstant (c.GetValue ());
 537                                         }
 538                                 }
 539                         }
 540                 }
 541
 542                 public override string[] ValidAttributeTargets {
 543                         get {
 544                                 return attribute_targets;
 545                         }
 546                 }
 547
 548                 public Parameter Clone ()
 549                 {
 550                         Parameter p = (Parameter) MemberwiseClone ();
 551                         if (attributes != null) {
 552                                 p.attributes = attributes.Clone ();
 553                                 p.attributes.AttachTo (p);
 554                         }
 555
 556                         return p;
 557                 }
 558
 559                 public ExpressionStatement CreateExpressionTreeVariable (EmitContext ec)
 560                 {
 561                         //
 562                         // A parameter is not hoisted when used directly as ET
 563                         //
 564                         HoistedVariableReference = null;
 565
 566                         if ((modFlags & Modifier.ISBYREF) != 0)
 567                                 Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");
 568
 569                         LocalInfo variable = ec.CurrentBlock.AddTemporaryVariable (
 570                                 ResolveParameterExpressionType (ec, Location), Location);
 571                         variable.Resolve (ec);
 572
 573                         expr_tree_variable = new LocalVariableReference (
 574                                 ec.CurrentBlock, variable.Name, Location, variable, false);
 575
 576                         Arguments arguments = new Arguments (2);
 577                         arguments.Add (new Argument (new TypeOf (
 578                                 new TypeExpression (parameter_type, Location), Location)));
 579                         arguments.Add (new Argument (new StringConstant (Name, Location)));
 580                         return new SimpleAssign (ExpressionTreeVariableReference (),
 581                                 Expression.CreateExpressionFactoryCall ("Parameter", null, arguments, Location));
 582                 }
 583
 584                 public Expression DefaultValue {
 585                         get { return default_expr; }
 586                         set { default_expr = value; }
 587                 }
 588
 589                 public void Emit (EmitContext ec)
 590                 {
 591                         int arg_idx = idx;
 592                         if (!ec.IsStatic)
 593                                 arg_idx++;
 594
 595                         ParameterReference.EmitLdArg (ec.ig, arg_idx);
 596                 }
 597
 598                 public void EmitAssign (EmitContext ec)
 599                 {
 600                         int arg_idx = idx;
 601                         if (!ec.IsStatic)
 602                                 arg_idx++;
 603
 604                         if (arg_idx <= 255)
 605                                 ec.ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
 606                         else
 607                                 ec.ig.Emit (OpCodes.Starg, arg_idx);
 608                 }
 609
 610                 public void EmitAddressOf (EmitContext ec)
 611                 {
 612                         int arg_idx = idx;
 613
 614                         if (!ec.IsStatic)
 615                                 arg_idx++;
 616
 617                         bool is_ref = (ModFlags & Modifier.ISBYREF) != 0;
 618                         if (is_ref) {
 619                                 ParameterReference.EmitLdArg (ec.ig, arg_idx);
 620                         } else {
 621                                 if (arg_idx <= 255)
 622                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
 623                                 else
 624                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
 625                         }
 626                 }
 627
 628                 public Expression ExpressionTreeVariableReference ()
 629                 {
 630                         return expr_tree_variable;
 631                 }
 632
 633                 //
 634                 // System.Linq.Expressions.ParameterExpression type
 635                 //
 636                 public static TypeExpr ResolveParameterExpressionType (EmitContext ec, Location location)
 637                 {
 638                         if (parameter_expr_tree_type != null)
 639                                 return parameter_expr_tree_type;
 640
 641                         Type p_type = TypeManager.parameter_expression_type;
 642                         if (p_type == null) {
 643                                 p_type = TypeManager.CoreLookupType ("System.Linq.Expressions", "ParameterExpression", Kind.Class, true);
 644                                 TypeManager.parameter_expression_type = p_type;
 645                         }
 646
 647                         parameter_expr_tree_type = new TypeExpression (p_type, location).
 648                                 ResolveAsTypeTerminal (ec, false);
 649
 650                         return parameter_expr_tree_type;
 651                 }
 652
 653                 public void Warning_UselessOptionalParameter ()
 654                 {
 655                         Report.Warning (1066, 1, Location,
 656                                 "The default value specified for optional parameter `{0}' will never be used",
 657                                 Name);
 658                 }
 659         }
 660
 661         //
 662         // Imported or resolved parameter information
 663         //
 664         public class ParameterData : IParameterData
 665         {
 666                 readonly string name;
 667                 readonly Parameter.Modifier modifiers;
 668                 readonly Expression default_value;
 669
 670                 public ParameterData (string name, Parameter.Modifier modifiers)
 671                 {
 672                         this.name = name;
 673                         this.modifiers = modifiers;
 674                 }
 675
 676                 public ParameterData (string name, Parameter.Modifier modifiers, Expression defaultValue)
 677                         : this (name, modifiers)
 678                 {
 679                         this.default_value = defaultValue;
 680                 }
 681
 682                 #region IParameterData Members
 683
 684                 public Expression DefaultValue {
 685                         get { return default_value; }
 686                 }
 687
 688                 public bool HasExtensionMethodModifier {
 689                         get { return (modifiers & Parameter.Modifier.This) != 0; }
 690                 }
 691
 692                 public bool HasDefaultValue {
 693                         get { return default_value != null; }
 694                 }
 695
 696                 public Parameter.Modifier ModFlags {
 697                         get { return modifiers & ~Parameter.Modifier.This; }
 698                 }
 699
 700                 public string Name {
 701                         get { return name; }
 702                 }
 703
 704                 #endregion
 705         }
 706
 707         public abstract class AParametersCollection
 708         {
 709                 protected bool has_arglist;
 710                 protected bool has_params;
 711
 712                 // Null object pattern
 713                 protected IParameterData [] parameters;
 714                 protected Type [] types;
 715
 716                 public int Count {
 717                         get { return parameters.Length; }
 718                 }
 719
 720                 public Type ExtensionMethodType {
 721                         get {
 722                                 if (Count == 0)
 723                                         return null;
 724
 725                                 return FixedParameters [0].HasExtensionMethodModifier ?
 726                                         types [0] : null;
 727                         }
 728                 }
 729
 730                 public IParameterData [] FixedParameters {
 731                         get {
 732                                 return parameters;
 733                         }
 734                 }
 735
 736                 public static ParameterAttributes GetParameterAttribute (Parameter.Modifier modFlags)
 737                 {
 738                         return (modFlags & Parameter.Modifier.OUT) == Parameter.Modifier.OUT ?
 739                                 ParameterAttributes.Out : ParameterAttributes.None;
 740                 }
 741
 742                 public Type [] GetEmitTypes ()
 743                 {
 744                         Type [] types = null;
 745                         if (has_arglist) {
 746                                 if (Count == 1)
 747                                         return Type.EmptyTypes;
 748
 749                                 types = new Type [Count - 1];
 750                                 Array.Copy (Types, types, types.Length);
 751                         }
 752
 753                         for (int i = 0; i < Count; ++i) {
 754                                 if ((FixedParameters [i].ModFlags & Parameter.Modifier.ISBYREF) == 0)
 755                                         continue;
 756
 757                                 if (types == null)
 758                                         types = (Type []) Types.Clone ();
 759
 760                                 types [i] = TypeManager.GetReferenceType (types [i]);
 761                         }
 762
 763                         if (types == null)
 764                                 types = Types;
 765
 766                         return types;
 767                 }
 768
 769                 //
 770                 // Returns the parameter information based on the name
 771                 //
 772                 public int GetParameterIndexByName (string name)
 773                 {
 774                         for (int idx = 0; idx < Count; ++idx) {
 775                                 if (parameters [idx].Name == name)
 776                                         return idx;
 777                         }
 778
 779                         return -1;
 780                 }
 781
 782                 public string GetSignatureForError ()
 783                 {
 784                         StringBuilder sb = new StringBuilder ("(");
 785                         for (int i = 0; i < Count; ++i) {
 786                                 if (i != 0)
 787                                         sb.Append (", ");
 788                                 sb.Append (ParameterDesc (i));
 789                         }
 790                         sb.Append (')');
 791                         return sb.ToString ();
 792                 }
 793
 794                 public bool HasArglist {
 795                         get { return has_arglist; }
 796                 }
 797
 798                 public bool HasExtensionMethodType {
 799                         get {
 800                                 if (Count == 0)
 801                                         return false;
 802
 803                                 return FixedParameters [0].HasExtensionMethodModifier;
 804                         }
 805                 }
 806
 807                 public bool HasParams {
 808                         get { return has_params; }
 809                 }
 810
 811                 public bool IsEmpty {
 812                         get { return parameters.Length == 0; }
 813                 }
 814
 815                 public string ParameterDesc (int pos)
 816                 {
 817                         if (types == null || types [pos] == null)
 818                                 return ((Parameter)FixedParameters [pos]).GetSignatureForError ();
 819
 820                         string type = TypeManager.CSharpName (types [pos]);
 821                         if (FixedParameters [pos].HasExtensionMethodModifier)
 822                                 return "this " + type;
 823
 824                         Parameter.Modifier mod = FixedParameters [pos].ModFlags;
 825                         if (mod == 0)
 826                                 return type;
 827
 828                         return Parameter.GetModifierSignature (mod) + " " + type;
 829                 }
 830
 831                 public Type[] Types {
 832                         get { return types; }
 833                         set { types = value; }
 834                 }
 835
 836 #if MS_COMPATIBLE
 837                 public AParametersCollection InflateTypes (Type[] genArguments, Type[] argTypes)
 838                 {
 839                         AParametersCollection p = (AParametersCollection) MemberwiseClone (); // Clone ();
 840
 841                         for (int i = 0; i < Count; ++i) {
 842                                 if (types[i].IsGenericType) {
 843                                         Type[] gen_arguments_open = new Type[types[i].GetGenericTypeDefinition ().GetGenericArguments ().Length];
 844                                         Type[] gen_arguments = types[i].GetGenericArguments ();
 845                                         for (int ii = 0; ii < gen_arguments_open.Length; ++ii) {
 846                                                 if (gen_arguments[ii].IsGenericParameter) {
 847                                                         Type t = argTypes[gen_arguments[ii].GenericParameterPosition];
 848                                                         gen_arguments_open[ii] = t;
 849                                                 } else
 850                                                         gen_arguments_open[ii] = gen_arguments[ii];
 851                                         }
 852
 853                                         p.types[i] = types[i].GetGenericTypeDefinition ().MakeGenericType (gen_arguments_open);
 854                                         continue;
 855                                 }
 856
 857                                 if (types[i].IsGenericParameter) {
 858                                         Type gen_argument = argTypes[types[i].GenericParameterPosition];
 859                                         p.types[i] = gen_argument;
 860                                         continue;
 861                                 }
 862                         }
 863
 864                         return p;
 865                 }
 866 #endif
 867         }
 868
 869         //
 870         // A collection of imported or resolved parameters
 871         //
 872         public class ParametersImported : AParametersCollection
 873         {
 874                 ParametersImported (AParametersCollection param, Type[] types)
 875                 {
 876                         this.parameters = param.FixedParameters;
 877                         this.types = types;
 878                         has_arglist = param.HasArglist;
 879                         has_params = param.HasParams;
 880                 }
 881
 882                 ParametersImported (IParameterData [] parameters, Type [] types, bool hasArglist, bool hasParams)
 883                 {
 884                         this.parameters = parameters;
 885                         this.types = types;
 886                         this.has_arglist = hasArglist;
 887                         this.has_params = hasParams;
 888                 }
 889
 890                 public ParametersImported (IParameterData [] param, Type[] types)
 891                 {
 892                         this.parameters = param;
 893                         this.types = types;
 894                 }
 895
 896                 public static AParametersCollection Create (MethodBase method)
 897                 {
 898                         return Create (method.GetParameters (), method);
 899                 }
 900
 901                 //
 902                 // Generic method parameters importer, param is shared between all instances
 903                 //
 904                 public static AParametersCollection Create (AParametersCollection param, MethodBase method)
 905                 {
 906                         if (param.IsEmpty)
 907                                 return param;
 908
 909                         ParameterInfo [] pi = method.GetParameters ();
 910                         Type [] types = new Type [pi.Length];
 911                         for (int i = 0; i < types.Length; i++) {
 912                                 Type t = pi [i].ParameterType;
 913                                 if (t.IsByRef)
 914                                         t = TypeManager.GetElementType (t);
 915
 916                                 types [i] = TypeManager.TypeToCoreType (t);
 917                         }
 918
 919                         return new ParametersImported (param, types);
 920                 }
 921
 922                 //
 923                 // Imports SRE parameters
 924                 //
 925                 public static AParametersCollection Create (ParameterInfo [] pi, MethodBase method)
 926                 {
 927                         int varargs = method != null && (method.CallingConvention & CallingConventions.VarArgs) != 0 ? 1 : 0;
 928
 929                         if (pi.Length == 0 && varargs == 0)
 930                                 return ParametersCompiled.EmptyReadOnlyParameters;
 931
 932                         Type [] types = new Type [pi.Length + varargs];
 933                         IParameterData [] par = new IParameterData [pi.Length + varargs];
 934                         bool is_params = false;
 935                         PredefinedAttribute extension_attr = PredefinedAttributes.Get.Extension;
 936                         PredefinedAttribute param_attr = PredefinedAttributes.Get.ParamArray;
 937                         for (int i = 0; i < pi.Length; i++) {
 938                                 types [i] = TypeManager.TypeToCoreType (pi [i].ParameterType);
 939
 940                                 ParameterInfo p = pi [i];
 941                                 Parameter.Modifier mod = 0;
 942                                 Expression default_value = null;
 943                                 if (types [i].IsByRef) {
 944                                         if ((p.Attributes & (ParameterAttributes.Out | ParameterAttributes.In)) == ParameterAttributes.Out)
 945                                                 mod = Parameter.Modifier.OUT;
 946                                         else
 947                                                 mod = Parameter.Modifier.REF;
 948
 949                                         //
 950                                         // Strip reference wrapping
 951                                         //
 952                                         types [i] = TypeManager.GetElementType (types [i]);
 953                                 } else if (i == 0 && extension_attr.IsDefined && method != null && method.IsStatic &&
 954                                 (method.DeclaringType.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 955                                         method.IsDefined (extension_attr.Type, false)) {
 956                                         mod = Parameter.Modifier.This;
 957                                 } else {
 958                                         if (i >= pi.Length - 2 && types[i].IsArray) {
 959                                                 if (p.IsDefined (param_attr.Type, false)) {
 960                                                         mod = Parameter.Modifier.PARAMS;
 961                                                         is_params = true;
 962                                                 }
 963                                         }
 964
 965                                         if (!is_params && p.IsOptional) {
 966                                                 if (p.DefaultValue == Missing.Value)
 967                                                         default_value = EmptyExpression.Null;
 968                                                 else
 969                                                         default_value = Constant.CreateConstant (types[i], p.DefaultValue, Location.Null);
 970                                         }
 971                                 }
 972
 973                                 par [i] = new ParameterData (p.Name, mod, default_value);
 974                         }
 975
 976                         if (varargs != 0) {
 977                                 par [par.Length - 1] = new ArglistParameter (Location.Null);
 978                                 types [types.Length - 1] = typeof (ArglistAccess);
 979                         }
 980
 981                         return method != null ?
 982                                 new ParametersImported (par, types, varargs != 0, is_params) :
 983                                 new ParametersImported (par, types);
 984                 }
 985         }
 986
 987         /// <summary>
 988         ///   Represents the methods parameters
 989         /// </summary>
 990         public class ParametersCompiled : AParametersCollection
 991         {
 992                 public static readonly ParametersCompiled EmptyReadOnlyParameters = new ParametersCompiled ();
 993
 994                 // Used by C# 2.0 delegates
 995                 public static readonly ParametersCompiled Undefined = new ParametersCompiled ();
 996
 997                 private ParametersCompiled ()
 998                 {
 999                         parameters = new Parameter [0];
1000                         types = Type.EmptyTypes;
1001                 }
1002
1003                 private ParametersCompiled (Parameter [] parameters, Type [] types)
1004                 {
1005                         this.parameters = parameters;
1006                     this.types = types;
1007                 }
1008
1009                 public ParametersCompiled (params Parameter[] parameters)
1010                 {
1011                         if (parameters == null)
1012                                 throw new ArgumentException ("Use EmptyReadOnlyParameters");
1013
1014                         this.parameters = parameters;
1015                         int count = parameters.Length;
1016
1017                         if (count == 0)
1018                                 return;
1019
1020                         if (count == 1) {
1021                                 has_params = (parameters [0].ModFlags & Parameter.Modifier.PARAMS) != 0;
1022                                 return;
1023                         }
1024
1025                         for (int i = 0; i < count; i++){
1026                                 string base_name = parameters [i].Name;
1027                                 has_params |= (parameters [i].ModFlags & Parameter.Modifier.PARAMS) != 0;
1028
1029                                 for (int j = i + 1; j < count; j++){
1030                                         if (base_name != parameters [j].Name)
1031                                                 continue;
1032
1033                                         ErrorDuplicateName (parameters [i]);
1034                                         i = j;
1035                                 }
1036                         }
1037                 }
1038
1039                 public ParametersCompiled (Parameter [] parameters, bool has_arglist) :
1040                         this (parameters)
1041                 {
1042                         this.has_arglist = has_arglist;
1043                 }
1044
1045                 public static ParametersCompiled CreateFullyResolved (Parameter p, Type type)
1046                 {
1047                         return new ParametersCompiled (new Parameter [] { p }, new Type [] { type });
1048                 }
1049
1050                 public static ParametersCompiled CreateFullyResolved (Parameter[] parameters, Type[] types)
1051                 {
1052                         return new ParametersCompiled (parameters, types);
1053                 }
1054
1055                 public static ParametersCompiled MergeGenerated (ParametersCompiled userParams, bool checkConflicts, Parameter compilerParams, Type compilerTypes)
1056                 {
1057                         return MergeGenerated (userParams, checkConflicts,
1058                                 new Parameter [] { compilerParams },
1059                                 new Type [] { compilerTypes });
1060                 }
1061
1062                 //
1063                 // Use this method when you merge compiler generated parameters with user parameters
1064                 //
1065                 public static ParametersCompiled MergeGenerated (ParametersCompiled userParams, bool checkConflicts, Parameter[] compilerParams, Type[] compilerTypes)
1066                 {
1067                         Parameter[] all_params = new Parameter [userParams.Count + compilerParams.Length];
1068                         userParams.FixedParameters.CopyTo(all_params, 0);
1069
1070                         Type [] all_types;
1071                         if (userParams.types != null) {
1072                                 all_types = new Type [all_params.Length];
1073                                 userParams.Types.CopyTo (all_types, 0);
1074                         } else {
1075                                 all_types = null;
1076                         }
1077
1078                         int last_filled = userParams.Count;
1079                         int index = 0;
1080                         foreach (Parameter p in compilerParams) {
1081                                 for (int i = 0; i < last_filled; ++i) {
1082                                         while (p.Name == all_params [i].Name) {
1083                                                 if (checkConflicts && i < userParams.Count) {
1084                                                         Report.Error (316, userParams [i].Location,
1085                                                                 "The parameter name `{0}' conflicts with a compiler generated name", p.Name);
1086                                                 }
1087                                                 p.Name = '_' + p.Name;
1088                                         }
1089                                 }
1090                                 all_params [last_filled] = p;
1091                                 if (all_types != null)
1092                                         all_types [last_filled] = compilerTypes [index++];
1093                                 ++last_filled;
1094                         }
1095
1096                         ParametersCompiled parameters = new ParametersCompiled (all_params, all_types);
1097                         parameters.has_params = userParams.has_params;
1098                         return parameters;
1099                 }
1100
1101                 protected virtual void ErrorDuplicateName (Parameter p)
1102                 {
1103                         Report.Error (100, p.Location, "The parameter name `{0}' is a duplicate", p.Name);
1104                 }
1105
1106                 public bool Resolve (IResolveContext ec)
1107                 {
1108                         if (types != null)
1109                                 return true;
1110
1111                         types = new Type [Count];
1112
1113                         bool ok = true;
1114                         Parameter p;
1115                         for (int i = 0; i < FixedParameters.Length; ++i) {
1116                                 p = this [i];
1117                                 Type t = p.Resolve (ec);
1118                                 if (t == null) {
1119                                         ok = false;
1120                                         continue;
1121                                 }
1122
1123                                 types [i] = t;
1124                         }
1125
1126                         return ok;
1127                 }
1128
1129                 public void ResolveVariable ()
1130                 {
1131                         for (int i = 0; i < FixedParameters.Length; ++i) {
1132                                 this [i].ResolveVariable (i);
1133                         }
1134                 }
1135
1136                 public CallingConventions CallingConvention
1137                 {
1138                         get {
1139                                 if (HasArglist)
1140                                         return CallingConventions.VarArgs;
1141                                 else
1142                                         return CallingConventions.Standard;
1143                         }
1144                 }
1145
1146                 // Define each type attribute (in/out/ref) and
1147                 // the argument names.
1148                 public void ApplyAttributes (MethodBase builder)
1149                 {
1150                         if (Count == 0)
1151                                 return;
1152
1153                         MethodBuilder mb = builder as MethodBuilder;
1154                         ConstructorBuilder cb = builder as ConstructorBuilder;
1155
1156                         for (int i = 0; i < Count; i++) {
1157                                 this [i].ApplyAttributes (mb, cb, i + 1);
1158                         }
1159                 }
1160
1161                 public void VerifyClsCompliance ()
1162                 {
1163                         foreach (Parameter p in FixedParameters)
1164                                 p.IsClsCompliant ();
1165                 }
1166
1167                 public Parameter this [int pos] {
1168                         get { return (Parameter) parameters [pos]; }
1169                 }
1170
1171                 public Expression CreateExpressionTree (EmitContext ec, Location loc)
1172                 {
1173                         ArrayList initializers = new ArrayList (Count);
1174                         foreach (Parameter p in FixedParameters) {
1175                                 //
1176                                 // Each parameter expression is stored to local variable
1177                                 // to save some memory when referenced later.
1178                                 //
1179                                 StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec));
1180                                 if (se.Resolve (ec))
1181                                         ec.CurrentBlock.AddScopeStatement (se);
1182
1183                                 initializers.Add (p.ExpressionTreeVariableReference ());
1184                         }
1185
1186                         return new ArrayCreation (
1187                                 Parameter.ResolveParameterExpressionType (ec, loc),
1188                                 "[]", initializers, loc);
1189                 }
1190
1191                 public ParametersCompiled Clone ()
1192                 {
1193                         ParametersCompiled p = (ParametersCompiled) MemberwiseClone ();
1194
1195                         p.parameters = new IParameterData [parameters.Length];
1196                         for (int i = 0; i < Count; ++i)
1197                                 p.parameters [i] = this [i].Clone ();
1198
1199                         return p;
1200                 }
1201         }
1202 }