mcs/gmcs/parameter.cs

   1 //
   2 // parameter.cs: Parameter definition.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //
   6 // Licensed under the terms of the GNU GPL
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10 //
  11 //
  12 using System;
  13 using System.Reflection;
  14 using System.Reflection.Emit;
  15 using System.Collections;
  16 using System.Text;
  17
  18 namespace Mono.CSharp {
  19
  20         /// <summary>
  21         ///   Abstract Base class for parameters of a method.
  22         /// </summary>
  23         public abstract class ParameterBase : Attributable {
  24
  25                 protected ParameterBuilder builder;
  26                 public readonly Location Location;
  27
  28                 public ParameterBase (Attributes attrs, Location loc)
  29                         : base (attrs)
  30                 {
  31                         Location = loc;
  32                 }
  33
  34                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
  35                 {
  36                         if (a.Type == TypeManager.marshal_as_attr_type) {
  37                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  38                                 if (marshal != null) {
  39                                         builder.SetMarshal (marshal);
  40                                 }
  41                                         return;
  42                         }
  43
  44                         if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
  45                                 a.Error_InvalidSecurityParent ();
  46                                 return;
  47                         }
  48
  49                         builder.SetCustomAttribute (cb);
  50                 }
  51
  52                 public override bool IsClsComplianceRequired(DeclSpace ds)
  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, location)
  64                 {
  65                         try {
  66                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  67                         }
  68                         catch (ArgumentOutOfRangeException) {
  69                                 Report.Warning (-24, location, "The Microsoft .NET Runtime 1.x does not permit setting custom attributes on the return type");
  70                         }
  71                 }
  72
  73                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  74                 {
  75                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
  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);
  84                 }
  85
  86                 public override AttributeTargets AttributeTargets {
  87                         get {
  88                                 return AttributeTargets.ReturnValue;
  89                         }
  90                 }
  91
  92                 /// <summary>
  93                 /// Is never called
  94                 /// </summary>
  95                 public override string[] ValidAttributeTargets {
  96                         get {
  97                                 return null;
  98                         }
  99                 }
 100         }
 101
 102         /// <summary>
 103        /// Class for applying custom attributes on the implicit parameter type
 104        /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
 105         /// </summary>
 106         public class ImplicitParameter : ParameterBase {
 107                 public ImplicitParameter (MethodBuilder mb, Location loc):
 108                         base (null, loc)
 109                 {
 110                         builder = mb.DefineParameter (1, ParameterAttributes.None, "");
 111                 }
 112
 113                 public override AttributeTargets AttributeTargets {
 114                         get {
 115                                 return AttributeTargets.Parameter;
 116                         }
 117                 }
 118
 119                 /// <summary>
 120                 /// Is never called
 121                 /// </summary>
 122                 public override string[] ValidAttributeTargets {
 123                         get {
 124                                 return null;
 125                         }
 126         }
 127         }
 128
 129
 130         /// <summary>
 131         ///   Represents a single method parameter
 132         /// </summary>
 133         public class Parameter : ParameterBase {
 134                 [Flags]
 135                 public enum Modifier : byte {
 136                         NONE    = 0,
 137                         REF     = 1,
 138                         OUT     = 2,
 139                         PARAMS  = 4,
 140                         // This is a flag which says that it's either REF or OUT.
 141                         ISBYREF = 8,
 142                         ARGLIST = 16
 143                 }
 144
 145                 static string[] attribute_targets = new string [] { "param" };
 146
 147                 public Expression TypeName;
 148                 public readonly Modifier ModFlags;
 149                 public readonly string Name;
 150                 GenericConstraints constraints;
 151                 Type parameter_type;
 152
 153                 EmitContext ec;  // because ApplyAtrribute doesn't have ec
 154
 155                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs, Location loc)
 156                         : base (attrs, loc)
 157                 {
 158                         Name = name;
 159                         ModFlags = mod;
 160                         TypeName = type;
 161                 }
 162
 163                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
 164                 {
 165                         if (a.Type == TypeManager.in_attribute_type && Attributes == ParameterAttributes.Out) {
 166                                 Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
 167                                 return;
 168                         }
 169
 170                         if (a.Type == TypeManager.param_array_type) {
 171                                 Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
 172                                 return;
 173                         }
 174
 175                         if (a.Type == TypeManager.out_attribute_type && (ModFlags & Modifier.REF) != 0 &&
 176                             !OptAttributes.Contains (TypeManager.in_attribute_type, ec)) {
 177                                 Report.Error (662, a.Location,
 178                                         "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
 179                                 return;
 180                         }
 181
 182                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
 183                                 Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 184                         }
 185
 186                         base.ApplyAttributeBuilder (a, cb);
 187                 }
 188
 189                 // <summary>
 190                 //   Resolve is used in method definitions
 191                 // </summary>
 192                 public bool Resolve (EmitContext ec)
 193                 {
 194                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (ec);
 195                         this.ec = ec;
 196
 197                         if (texpr == null)
 198                                 return false;
 199
 200                         TypeParameterExpr tparam = texpr as TypeParameterExpr;
 201                         if (tparam != null)
 202                                 constraints = tparam.TypeParameter.Constraints;
 203
 204                         parameter_type = texpr.Type;
 205
 206                         if (parameter_type.IsAbstract && parameter_type.IsSealed) {
 207                                 Report.Error (721, Location, "`{0}': static types cannot be used as parameters", GetSignatureForError ());
 208                                 return false;
 209                         }
 210
 211                         if (parameter_type == TypeManager.void_type){
 212                                 Report.Error (1536, Location, "Invalid parameter type 'void'");
 213                                 return false;
 214                         }
 215
 216                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 217                                 if (parameter_type == TypeManager.typed_reference_type ||
 218                                     parameter_type == TypeManager.arg_iterator_type){
 219                                         Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
 220                                                 GetSignatureForError ());
 221                                         return false;
 222                                 }
 223                         }
 224
 225                         return parameter_type != null;
 226                 }
 227
 228                 public Type ExternalType ()
 229                 {
 230                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 231                                 return TypeManager.GetReferenceType (parameter_type);
 232
 233                         return parameter_type;
 234                 }
 235
 236                 public Type ParameterType {
 237                         get {
 238                                 return parameter_type;
 239                         }
 240                 }
 241
 242                 public GenericConstraints GenericConstraints {
 243                         get {
 244                                 return constraints;
 245                         }
 246                 }
 247
 248                 public ParameterAttributes Attributes {
 249                         get {
 250                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 251                                 switch ((Modifier) flags) {
 252                                 case Modifier.NONE:
 253                                         return ParameterAttributes.None;
 254                                 case Modifier.REF:
 255                                         return ParameterAttributes.None;
 256                                 case Modifier.OUT:
 257                                         return ParameterAttributes.Out;
 258                                 case Modifier.PARAMS:
 259                                         return 0;
 260                                 }
 261
 262                                 return ParameterAttributes.None;
 263                         }
 264                 }
 265
 266                 public static ParameterAttributes GetParameterAttributes (Modifier mod)
 267                 {
 268                         int flags = ((int) mod) & ~((int) Parameter.Modifier.ISBYREF);
 269                         switch ((Modifier) flags) {
 270                         case Modifier.NONE:
 271                                 return ParameterAttributes.None;
 272                         case Modifier.REF:
 273                                 return ParameterAttributes.None;
 274                         case Modifier.OUT:
 275                                 return ParameterAttributes.Out;
 276                         case Modifier.PARAMS:
 277                                 return 0;
 278                         }
 279
 280                         return ParameterAttributes.None;
 281                 }
 282
 283                 public override AttributeTargets AttributeTargets {
 284                         get {
 285                                 return AttributeTargets.Parameter;
 286                         }
 287                 }
 288
 289                 /// <summary>
 290                 ///   Returns the signature for this parameter evaluating it on the
 291                 ///   @tc context
 292                 /// </summary>
 293                 public string GetSignature (EmitContext ec)
 294                 {
 295                         if (parameter_type == null){
 296                                 if (!Resolve (ec))
 297                                         return null;
 298                         }
 299
 300                         return ExternalType ().FullName;
 301                 }
 302
 303                 public string GetSignatureForError ()
 304                 {
 305                         string type_name;
 306                         if (parameter_type != null)
 307                                 type_name = TypeManager.CSharpName (parameter_type);
 308                         else if (TypeName.Type != null)
 309                                 type_name = TypeManager.CSharpName (TypeName.Type);
 310                         else
 311                                 type_name = TypeName.ToString ();
 312
 313                         string mod = GetModifierSignature (ModFlags);
 314                         if (mod.Length > 0)
 315                                 return String.Concat (mod, " ", type_name);
 316
 317                         return type_name;
 318                 }
 319
 320                 public static string GetModifierSignature (Modifier mod)
 321                 {
 322                         switch (mod & unchecked (~Modifier.ISBYREF)) {
 323                                 case Modifier.OUT:
 324                                         return "out";
 325                                 case Modifier.PARAMS:
 326                                         return "params";
 327                                 case Modifier.REF:
 328                                         return "ref";
 329                                 case Modifier.ARGLIST:
 330                                         return "__arglist";
 331                                 default:
 332                                         return "";
 333                         }
 334                 }
 335
 336                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index)
 337                 {
 338                         ParameterAttributes par_attr = Attributes;
 339
 340                         if (mb == null)
 341                                 builder = cb.DefineParameter (index, par_attr, Name);
 342                         else
 343                                 builder = mb.DefineParameter (index, par_attr, Name);
 344
 345                         if (OptAttributes != null) {
 346                                 OptAttributes.Emit (ec, this);
 347                         }
 348                 }
 349
 350                 public override string[] ValidAttributeTargets {
 351                         get {
 352                                 return attribute_targets;
 353                         }
 354                 }
 355         }
 356
 357         /// <summary>
 358         ///   Represents the methods parameters
 359         /// </summary>
 360         public class Parameters {
 361                 public Parameter [] FixedParameters;
 362                 public readonly Parameter ArrayParameter;
 363                 public readonly bool HasArglist;
 364                 string signature;
 365                 Type [] types;
 366
 367                 static Parameters empty_parameters;
 368
 369                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter)
 370                 {
 371                         FixedParameters = fixed_parameters;
 372                         ArrayParameter  = array_parameter;
 373                 }
 374
 375                 public Parameters (Parameter [] fixed_parameters, bool has_arglist)
 376                 {
 377                         FixedParameters = fixed_parameters;
 378                         HasArglist = has_arglist;
 379                 }
 380
 381                 /// <summary>
 382                 ///   This is used to reuse a set of empty parameters, because they
 383                 ///   are common
 384                 /// </summary>
 385                 public static Parameters EmptyReadOnlyParameters {
 386                         get {
 387                                 if (empty_parameters == null)
 388                                         empty_parameters = new Parameters (null, null);
 389
 390                                 return empty_parameters;
 391                         }
 392                 }
 393
 394                 public bool Empty {
 395                         get {
 396                                 return (FixedParameters == null) && (ArrayParameter == null);
 397                         }
 398                 }
 399
 400                 public void ComputeSignature (EmitContext ec)
 401                 {
 402                         signature = "";
 403                         if (FixedParameters != null){
 404                                 for (int i = 0; i < FixedParameters.Length; i++){
 405                                         Parameter par = FixedParameters [i];
 406
 407                                         signature += par.GetSignature (ec);
 408                                 }
 409                         }
 410                         //
 411                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 412                         // are not used in the signature computation for a method
 413                         //
 414                 }
 415
 416                 void Error_DuplicateParameterName (string name, Location loc)
 417                 {
 418                         Report.Error (
 419                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 420                 }
 421
 422                 public bool VerifyArgs ()
 423                 {
 424                         int count;
 425                         int i, j;
 426
 427                         if (FixedParameters == null)
 428                                 return true;
 429
 430                         count = FixedParameters.Length;
 431                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 432
 433                         for (i = 0; i < count; i++){
 434                                 string base_name = FixedParameters [i].Name;
 435                                 for (j = i + 1; j < count; j++){
 436                                         if (base_name != FixedParameters [j].Name)
 437                                                 continue;
 438                                         Error_DuplicateParameterName (base_name,
 439                                                 FixedParameters [i].Location);
 440                                         return false;
 441                                 }
 442
 443                                 if (base_name == array_par_name){
 444                                         Error_DuplicateParameterName (base_name,
 445                                                 FixedParameters [i].Location);
 446                                         return false;
 447                                 }
 448                         }
 449                         return true;
 450                 }
 451
 452                 /// <summary>
 453                 ///    Returns the signature of the Parameters evaluated in
 454                 ///    the @ec EmitContext
 455                 /// </summary>
 456                 public string GetSignature (EmitContext ec)
 457                 {
 458                         if (signature == null){
 459                                 VerifyArgs ();
 460                                 ComputeSignature (ec);
 461                         }
 462
 463                         return signature;
 464                 }
 465
 466                 /// <summary>
 467                 ///    Returns the paramenter information based on the name
 468                 /// </summary>
 469                 public Parameter GetParameterByName (string name, out int idx)
 470                 {
 471                         idx = 0;
 472                         int i = 0;
 473
 474                         if (FixedParameters != null){
 475                                 foreach (Parameter par in FixedParameters){
 476                                         if (par.Name == name){
 477                                                 idx = i;
 478                                                 return par;
 479                                         }
 480                                         i++;
 481                                 }
 482                         }
 483
 484                         if (ArrayParameter != null){
 485                                 if (name == ArrayParameter.Name){
 486                                         idx = i;
 487                                         return ArrayParameter;
 488                                 }
 489                         }
 490
 491                         return null;
 492                 }
 493
 494                 public Parameter GetParameterByName (string name)
 495                 {
 496                         int idx;
 497
 498                         return GetParameterByName (name, out idx);
 499                 }
 500
 501                 bool ComputeParameterTypes (EmitContext ec)
 502                 {
 503                         int extra = (ArrayParameter != null) ? 1 : 0;
 504                         int i = 0;
 505                         int pc;
 506
 507                         if (FixedParameters == null)
 508                                 pc = extra;
 509                         else
 510                                 pc = extra + FixedParameters.Length;
 511
 512                         types = new Type [pc];
 513
 514                         if (!VerifyArgs ()){
 515                                 FixedParameters = null;
 516                                 return false;
 517                         }
 518
 519                         bool failed = false;
 520                         if (FixedParameters != null){
 521                                 foreach (Parameter p in FixedParameters){
 522                                         Type t = null;
 523
 524                                         if (p.Resolve (ec))
 525                                                 t = p.ExternalType ();
 526                                         else
 527                                                 failed = true;
 528
 529                                         types [i] = t;
 530                                         i++;
 531                                 }
 532                         }
 533
 534                         if (extra > 0){
 535                                 if (ArrayParameter.Resolve (ec))
 536                                         types [i] = ArrayParameter.ExternalType ();
 537                                 else
 538                                         failed = true;
 539                         }
 540
 541                         if (failed){
 542                                 types = null;
 543                                 return false;
 544                         }
 545
 546                         return true;
 547                 }
 548
 549                 /// <summary>
 550                 ///   Returns the argument types as an array
 551                 /// </summary>
 552                 static Type [] no_types = new Type [0];
 553
 554                 public Type [] GetParameterInfo (EmitContext ec)
 555                 {
 556                         if (types != null)
 557                                 return types;
 558
 559                         if (FixedParameters == null && ArrayParameter == null)
 560                                 return no_types;
 561
 562                         if (ComputeParameterTypes (ec) == false){
 563                                 types = null;
 564                                 return null;
 565                         }
 566
 567                         return types;
 568                 }
 569
 570                 /// <summary>
 571                 ///   Returns the type of a given parameter, and stores in the `is_out'
 572                 ///   boolean whether this is an out or ref parameter.
 573                 ///
 574                 ///   Note that the returned type will not contain any dereference in this
 575                 ///   case (ie, you get "int" for a ref int instead of "int&"
 576                 /// </summary>
 577                 public Type GetParameterInfo (EmitContext ec, int idx, out Parameter.Modifier mod)
 578                 {
 579                         mod = Parameter.Modifier.NONE;
 580
 581                         if (!VerifyArgs ()){
 582                                 FixedParameters = null;
 583                                 return null;
 584                         }
 585
 586                         if (FixedParameters == null && ArrayParameter == null)
 587                                 return null;
 588
 589                         if (types == null)
 590                                 if (ComputeParameterTypes (ec) == false)
 591                                         return null;
 592
 593                         //
 594                         // If this is a request for the variable lenght arg.
 595                         //
 596                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 597                         if (idx == array_idx)
 598                                 return types [idx];
 599
 600                         //
 601                         // Otherwise, it is a fixed parameter
 602                         //
 603                         Parameter p = FixedParameters [idx];
 604                         mod = p.ModFlags;
 605
 606                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 607                                 mod |= Parameter.Modifier.ISBYREF;
 608
 609                         return p.ParameterType;
 610                 }
 611
 612                 public CallingConventions GetCallingConvention ()
 613                 {
 614                         if (HasArglist)
 615                                 return CallingConventions.VarArgs;
 616                         else
 617                         return CallingConventions.Standard;
 618                 }
 619
 620                 //
 621                 // The method's attributes are passed in because we need to extract
 622                 // the "return:" attribute from there to apply on the return type
 623                 //
 624                 public void LabelParameters (EmitContext ec, MethodBase builder)
 625                 {
 626                         //
 627                         // Define each type attribute (in/out/ref) and
 628                         // the argument names.
 629                         //
 630                         int i = 0;
 631
 632                         MethodBuilder mb = builder as MethodBuilder;
 633                         ConstructorBuilder cb = builder as ConstructorBuilder;
 634
 635                         if (FixedParameters != null) {
 636                                 for (i = 0; i < FixedParameters.Length; i++) {
 637                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1);
 638                                 }
 639                         }
 640
 641                         if (ArrayParameter != null){
 642                                 ParameterBuilder pb;
 643                                 Parameter array_param = ArrayParameter;
 644
 645                                 if (mb == null)
 646                                         pb = cb.DefineParameter (
 647                                                 i + 1, array_param.Attributes,
 648                                                 array_param.Name);
 649                                 else
 650                                         pb = mb.DefineParameter (
 651                                                 i + 1, array_param.Attributes,
 652                                                 array_param.Name);
 653
 654                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 655                                         TypeManager.cons_param_array_attribute, new object [0]);
 656
 657                                 pb.SetCustomAttribute (a);
 658                         }
 659                 }
 660
 661                 public string GetSignatureForError ()
 662                 {
 663                         StringBuilder sb = new StringBuilder ("(");
 664                         if (FixedParameters != null) {
 665                                 for (int i = 0; i < FixedParameters.Length; ++i) {
 666                                         sb.Append (FixedParameters[i].GetSignatureForError ());
 667                                         if (i < FixedParameters.Length - 1)
 668                                                 sb.Append (", ");
 669                                 }
 670                         }
 671                         if (ArrayParameter != null) {
 672                                 if (sb.Length > 0)
 673                                         sb.Append (", ");
 674                                 sb.Append (ArrayParameter.GetSignatureForError ());
 675                         }
 676                         if (HasArglist) {
 677                                 if (sb.Length > 0)
 678                                         sb.Append (", ");
 679                                 sb.Append ("__arglist");
 680                         }
 681                         sb.Append (')');
 682                         return sb.ToString ();
 683
 684                 }
 685         }
 686 }