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
  17 namespace Mono.CSharp {
  18
  19         /// <summary>
  20         ///   Abstract Base class for parameters of a method.
  21         /// </summary>
  22         public abstract class ParameterBase : Attributable {
  23
  24                 protected ParameterBuilder builder;
  25                 public readonly Location Location;
  26
  27                 public ParameterBase (Attributes attrs, Location loc)
  28                         : base (attrs)
  29                 {
  30                         Location = loc;
  31                 }
  32
  33                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
  34                 {
  35                         if (a.Type == TypeManager.marshal_as_attr_type) {
  36                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  37                                 if (marshal != null) {
  38                                         builder.SetMarshal (marshal);
  39                                 }
  40                                         return;
  41                         }
  42
  43                         if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
  44                                 a.Error_InvalidSecurityParent ();
  45                                 return;
  46                         }
  47
  48                         builder.SetCustomAttribute (cb);
  49                 }
  50
  51                 public override bool IsClsComplianceRequired(DeclSpace ds)
  52                 {
  53                         return false;
  54                 }
  55         }
  56
  57         /// <summary>
  58         /// Class for applying custom attributes on the return type
  59         /// </summary>
  60         public class ReturnParameter: ParameterBase {
  61                 public ReturnParameter (MethodBuilder mb, Location location):
  62                         base (null, location)
  63                 {
  64                         try {
  65                                 builder = mb.DefineParameter (0, ParameterAttributes.None, "");
  66                         }
  67                         catch (ArgumentOutOfRangeException) {
  68                                 Report.Warning (-24, location, "The Microsoft .NET Runtime 1.x does not permit setting custom attributes on the return type");
  69                         }
  70                 }
  71
  72                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  73                 {
  74                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
  75                                 Report.Warning (3023, 1, a.Location, "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
  76                         }
  77
  78                         // This occurs after Warning -28
  79                         if (builder == null)
  80                                 return;
  81
  82                         base.ApplyAttributeBuilder (a, cb);
  83                 }
  84
  85                 public override AttributeTargets AttributeTargets {
  86                         get {
  87                                 return AttributeTargets.ReturnValue;
  88                         }
  89                 }
  90
  91                 /// <summary>
  92                 /// Is never called
  93                 /// </summary>
  94                 public override string[] ValidAttributeTargets {
  95                         get {
  96                                 return null;
  97                         }
  98                 }
  99         }
 100
 101         /// <summary>
 102        /// Class for applying custom attributes on the implicit parameter type
 103        /// of the 'set' method in properties, and the 'add' and 'remove' methods in events.
 104         /// </summary>
 105         public class ImplicitParameter: ParameterBase {
 106                 public ImplicitParameter (MethodBuilder mb, Location loc):
 107                         base (null, loc)
 108                 {
 109                         builder = mb.DefineParameter (1, ParameterAttributes.None, "");
 110                 }
 111
 112                 public override AttributeTargets AttributeTargets {
 113                         get {
 114                                 return AttributeTargets.Parameter;
 115                         }
 116                 }
 117
 118                 /// <summary>
 119                 /// Is never called
 120                 /// </summary>
 121                 public override string[] ValidAttributeTargets {
 122                         get {
 123                                 return null;
 124                         }
 125         }
 126         }
 127
 128
 129         /// <summary>
 130         ///   Represents a single method parameter
 131         /// </summary>
 132
 133         //TODO: Add location member to this or base class for better error location and all methods simplification.
 134         public class Parameter : ParameterBase {
 135                 [Flags]
 136                 public enum Modifier : byte {
 137                         NONE    = 0,
 138                         REF     = 1,
 139                         OUT     = 2,
 140                         PARAMS  = 4,
 141                         // This is a flag which says that it's either REF or OUT.
 142                         ISBYREF = 8,
 143                         ARGLIST = 16
 144                 }
 145
 146                 static string[] attribute_targets = new string [] { "param" };
 147
 148                 public Expression TypeName;
 149                 public readonly Modifier ModFlags;
 150                 public readonly string Name;
 151                 GenericConstraints constraints;
 152                 Type parameter_type;
 153
 154                 EmitContext ec;  // because ApplyAtrribute doesn't have ec
 155
 156                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs, Location loc)
 157                         : base (attrs, loc)
 158                 {
 159                         Name = name;
 160                         ModFlags = mod;
 161                         TypeName = type;
 162                 }
 163
 164                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
 165                 {
 166                         if (a.Type == TypeManager.in_attribute_type && Attributes == ParameterAttributes.Out) {
 167                                 Report.Error (36, a.Location, "Can not use [In] attribute on out parameter");
 168                                 return;
 169                         }
 170
 171                         if (a.Type == TypeManager.param_array_type) {
 172                                 Report.Error (674, a.Location, "Do not use 'System.ParamArrayAttribute'. Use the 'params' keyword instead");
 173                                 return;
 174                         }
 175
 176                         if (a.Type == TypeManager.out_attribute_type && (ModFlags & Modifier.REF) != 0 &&
 177                             !OptAttributes.Contains (TypeManager.in_attribute_type, ec)) {
 178                                 Report.Error (662, a.Location,
 179                                         "'{0}' cannot specify only Out attribute on a ref parameter. Use both In and Out attributes, or neither", GetSignatureForError ());
 180                                 return;
 181                         }
 182
 183                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
 184                                 Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
 185                         }
 186
 187                         base.ApplyAttributeBuilder (a, cb);
 188                 }
 189
 190                 // <summary>
 191                 //   Resolve is used in method definitions
 192                 // </summary>
 193                 public bool Resolve (EmitContext ec)
 194                 {
 195                         TypeExpr texpr = TypeName.ResolveAsTypeTerminal (ec);
 196                         this.ec = ec;
 197
 198                         if (texpr == null)
 199                                 return false;
 200
 201                         TypeParameterExpr tparam = texpr as TypeParameterExpr;
 202                         if (tparam != null)
 203                                 constraints = tparam.TypeParameter.Constraints;
 204
 205                         parameter_type = texpr.Type;
 206
 207                         if (parameter_type.IsAbstract && parameter_type.IsSealed) {
 208                                 Report.Error (721, Location, "'{0}': static types cannot be used as parameters", GetSignatureForError ());
 209                                 return false;
 210                         }
 211
 212                         if (parameter_type == TypeManager.void_type){
 213                                 Report.Error (1536, Location, "Invalid parameter type 'void'");
 214                                 return false;
 215                         }
 216
 217                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 218                                 if (parameter_type == TypeManager.typed_reference_type ||
 219                                     parameter_type == TypeManager.arg_iterator_type){
 220                                         Report.Error (1601, Location,
 221                                                       "out or ref parameter can not be of type TypedReference or ArgIterator");
 222                                         return false;
 223                                 }
 224                         }
 225
 226                         return parameter_type != null;
 227                 }
 228
 229                 public Type ExternalType ()
 230                 {
 231                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 232                                 return TypeManager.GetReferenceType (parameter_type);
 233
 234                         return parameter_type;
 235                 }
 236
 237                 public Type ParameterType {
 238                         get {
 239                                 return parameter_type;
 240                         }
 241                 }
 242
 243                 public GenericConstraints GenericConstraints {
 244                         get {
 245                                 return constraints;
 246                         }
 247                 }
 248
 249                 public ParameterAttributes Attributes {
 250                         get {
 251                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 252                                 switch ((Modifier) flags) {
 253                                 case Modifier.NONE:
 254                                         return ParameterAttributes.None;
 255                                 case Modifier.REF:
 256                                         return ParameterAttributes.None;
 257                                 case Modifier.OUT:
 258                                         return ParameterAttributes.Out;
 259                                 case Modifier.PARAMS:
 260                                         return 0;
 261                                 }
 262
 263                                 return ParameterAttributes.None;
 264                         }
 265                 }
 266
 267                 public static ParameterAttributes GetParameterAttributes (Modifier mod)
 268                 {
 269                         int flags = ((int) mod) & ~((int) Parameter.Modifier.ISBYREF);
 270                         switch ((Modifier) flags) {
 271                         case Modifier.NONE:
 272                                 return ParameterAttributes.None;
 273                         case Modifier.REF:
 274                                 return ParameterAttributes.None;
 275                         case Modifier.OUT:
 276                                 return ParameterAttributes.Out;
 277                         case Modifier.PARAMS:
 278                                 return 0;
 279                         }
 280
 281                         return ParameterAttributes.None;
 282                 }
 283
 284                 public override AttributeTargets AttributeTargets {
 285                         get {
 286                                 return AttributeTargets.Parameter;
 287                         }
 288                 }
 289
 290                 /// <summary>
 291                 ///   Returns the signature for this parameter evaluating it on the
 292                 ///   @tc context
 293                 /// </summary>
 294                 public string GetSignature (EmitContext ec)
 295                 {
 296                         if (parameter_type == null){
 297                                 if (!Resolve (ec))
 298                                         return null;
 299                         }
 300
 301                         return ExternalType ().FullName;
 302                 }
 303
 304                 public string GetSignatureForError ()
 305                 {
 306                         string type_name;
 307                         if (parameter_type != null)
 308                                 type_name = TypeManager.CSharpName (parameter_type);
 309                         else if (TypeName.Type != null)
 310                                 type_name = TypeManager.CSharpName (TypeName.Type);
 311                         else
 312                                 type_name = TypeName.ToString ();
 313
 314                         string mod = GetModifierSignature (ModFlags);
 315                         if (mod.Length > 0)
 316                                 return String.Concat (mod, " ", type_name);
 317
 318                         return type_name;
 319                 }
 320
 321                 public static string GetModifierSignature (Modifier mod)
 322                 {
 323                         switch (mod & unchecked (~Modifier.ISBYREF)) {
 324                                 case Modifier.OUT:
 325                                         return "out";
 326                                 case Modifier.PARAMS:
 327                                         return "params";
 328                                 case Modifier.REF:
 329                                         return "ref";
 330                                 case Modifier.ARGLIST:
 331                                         return "__arglist";
 332                                 default:
 333                                         return "";
 334                         }
 335                 }
 336
 337                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index, Location loc)
 338                 {
 339                         ParameterAttributes par_attr = Attributes;
 340
 341                         if (mb == null)
 342                                 builder = cb.DefineParameter (index, par_attr, Name);
 343                         else
 344                                 builder = mb.DefineParameter (index, par_attr, Name);
 345
 346                         if (OptAttributes != null) {
 347                                 OptAttributes.Emit (ec, this);
 348                         }
 349                 }
 350
 351                 public override string[] ValidAttributeTargets {
 352                         get {
 353                                 return attribute_targets;
 354                         }
 355                 }
 356         }
 357
 358         /// <summary>
 359         ///   Represents the methods parameters
 360         /// </summary>
 361         public class Parameters {
 362                 public Parameter [] FixedParameters;
 363                 public readonly Parameter ArrayParameter;
 364                 public readonly bool HasArglist;
 365                 string signature;
 366                 Type [] types;
 367
 368                 static Parameters empty_parameters;
 369
 370                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter)
 371                 {
 372                         FixedParameters = fixed_parameters;
 373                         ArrayParameter  = array_parameter;
 374                 }
 375
 376                 public Parameters (Parameter [] fixed_parameters, bool has_arglist)
 377                 {
 378                         FixedParameters = fixed_parameters;
 379                         HasArglist = has_arglist;
 380                 }
 381
 382                 /// <summary>
 383                 ///   This is used to reuse a set of empty parameters, because they
 384                 ///   are common
 385                 /// </summary>
 386                 public static Parameters EmptyReadOnlyParameters {
 387                         get {
 388                                 if (empty_parameters == null)
 389                                         empty_parameters = new Parameters (null, null);
 390
 391                                 return empty_parameters;
 392                         }
 393                 }
 394
 395                 public bool Empty {
 396                         get {
 397                                 return (FixedParameters == null) && (ArrayParameter == null);
 398                         }
 399                 }
 400
 401                 public void ComputeSignature (EmitContext ec)
 402                 {
 403                         signature = "";
 404                         if (FixedParameters != null){
 405                                 for (int i = 0; i < FixedParameters.Length; i++){
 406                                         Parameter par = FixedParameters [i];
 407
 408                                         signature += par.GetSignature (ec);
 409                                 }
 410                         }
 411                         //
 412                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 413                         // are not used in the signature computation for a method
 414                         //
 415                 }
 416
 417                 void Error_DuplicateParameterName (string name, Location loc)
 418                 {
 419                         Report.Error (
 420                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 421                 }
 422
 423                 public bool VerifyArgs ()
 424                 {
 425                         int count;
 426                         int i, j;
 427
 428                         if (FixedParameters == null)
 429                                 return true;
 430
 431                         count = FixedParameters.Length;
 432                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 433
 434                         for (i = 0; i < count; i++){
 435                                 string base_name = FixedParameters [i].Name;
 436                                 for (j = i + 1; j < count; j++){
 437                                         if (base_name != FixedParameters [j].Name)
 438                                                 continue;
 439                                         Error_DuplicateParameterName (base_name,
 440                                                 FixedParameters [i].Location);
 441                                         return false;
 442                                 }
 443
 444                                 if (base_name == array_par_name){
 445                                         Error_DuplicateParameterName (base_name,
 446                                                 FixedParameters [i].Location);
 447                                         return false;
 448                                 }
 449                         }
 450                         return true;
 451                 }
 452
 453                 /// <summary>
 454                 ///    Returns the signature of the Parameters evaluated in
 455                 ///    the @ec EmitContext
 456                 /// </summary>
 457                 public string GetSignature (EmitContext ec)
 458                 {
 459                         if (signature == null){
 460                                 VerifyArgs ();
 461                                 ComputeSignature (ec);
 462                         }
 463
 464                         return signature;
 465                 }
 466
 467                 /// <summary>
 468                 ///    Returns the paramenter information based on the name
 469                 /// </summary>
 470                 public Parameter GetParameterByName (string name, out int idx)
 471                 {
 472                         idx = 0;
 473                         int i = 0;
 474
 475                         if (FixedParameters != null){
 476                                 foreach (Parameter par in FixedParameters){
 477                                         if (par.Name == name){
 478                                                 idx = i;
 479                                                 return par;
 480                                         }
 481                                         i++;
 482                                 }
 483                         }
 484
 485                         if (ArrayParameter != null){
 486                                 if (name == ArrayParameter.Name){
 487                                         idx = i;
 488                                         return ArrayParameter;
 489                                 }
 490                         }
 491
 492                         return null;
 493                 }
 494
 495                 public Parameter GetParameterByName (string name)
 496                 {
 497                         int idx;
 498
 499                         return GetParameterByName (name, out idx);
 500                 }
 501
 502                 bool ComputeParameterTypes (EmitContext ec)
 503                 {
 504                         int extra = (ArrayParameter != null) ? 1 : 0;
 505                         int i = 0;
 506                         int pc;
 507
 508                         if (FixedParameters == null)
 509                                 pc = extra;
 510                         else
 511                                 pc = extra + FixedParameters.Length;
 512
 513                         types = new Type [pc];
 514
 515                         if (!VerifyArgs ()){
 516                                 FixedParameters = null;
 517                                 return false;
 518                         }
 519
 520                         bool failed = false;
 521                         if (FixedParameters != null){
 522                                 foreach (Parameter p in FixedParameters){
 523                                         Type t = null;
 524
 525                                         if (p.Resolve (ec))
 526                                                 t = p.ExternalType ();
 527                                         else
 528                                                 failed = true;
 529
 530                                         types [i] = t;
 531                                         i++;
 532                                 }
 533                         }
 534
 535                         if (extra > 0){
 536                                 if (ArrayParameter.Resolve (ec))
 537                                         types [i] = ArrayParameter.ExternalType ();
 538                                 else
 539                                         failed = true;
 540                         }
 541
 542                         if (failed){
 543                                 types = null;
 544                                 return false;
 545                         }
 546
 547                         return true;
 548                 }
 549
 550                 /// <summary>
 551                 ///   Returns the argument types as an array
 552                 /// </summary>
 553                 static Type [] no_types = new Type [0];
 554
 555                 public Type [] GetParameterInfo (EmitContext ec)
 556                 {
 557                         if (types != null)
 558                                 return types;
 559
 560                         if (FixedParameters == null && ArrayParameter == null)
 561                                 return no_types;
 562
 563                         if (ComputeParameterTypes (ec) == false){
 564                                 types = null;
 565                                 return null;
 566                         }
 567
 568                         return types;
 569                 }
 570
 571                 /// <summary>
 572                 ///   Returns the type of a given parameter, and stores in the `is_out'
 573                 ///   boolean whether this is an out or ref parameter.
 574                 ///
 575                 ///   Note that the returned type will not contain any dereference in this
 576                 ///   case (ie, you get "int" for a ref int instead of "int&"
 577                 /// </summary>
 578                 public Type GetParameterInfo (EmitContext ec, int idx, out Parameter.Modifier mod)
 579                 {
 580                         mod = Parameter.Modifier.NONE;
 581
 582                         if (!VerifyArgs ()){
 583                                 FixedParameters = null;
 584                                 return null;
 585                         }
 586
 587                         if (FixedParameters == null && ArrayParameter == null)
 588                                 return null;
 589
 590                         if (types == null)
 591                                 if (ComputeParameterTypes (ec) == false)
 592                                         return null;
 593
 594                         //
 595                         // If this is a request for the variable lenght arg.
 596                         //
 597                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 598                         if (idx == array_idx)
 599                                 return types [idx];
 600
 601                         //
 602                         // Otherwise, it is a fixed parameter
 603                         //
 604                         Parameter p = FixedParameters [idx];
 605                         mod = p.ModFlags;
 606
 607                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 608                                 mod |= Parameter.Modifier.ISBYREF;
 609
 610                         return p.ParameterType;
 611                 }
 612
 613                 public CallingConventions GetCallingConvention ()
 614                 {
 615                         if (HasArglist)
 616                                 return CallingConventions.VarArgs;
 617                         else
 618                         return CallingConventions.Standard;
 619                 }
 620
 621                 //
 622                 // The method's attributes are passed in because we need to extract
 623                 // the "return:" attribute from there to apply on the return type
 624                 //
 625                 public void LabelParameters (EmitContext ec,
 626                         MethodBase builder,
 627                         Location loc) {
 628                         //
 629                         // Define each type attribute (in/out/ref) and
 630                         // the argument names.
 631                         //
 632                         int i = 0;
 633
 634                         MethodBuilder mb = builder as MethodBuilder;
 635                         ConstructorBuilder cb = builder as ConstructorBuilder;
 636
 637                         if (FixedParameters != null) {
 638                                 for (i = 0; i < FixedParameters.Length; i++) {
 639                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1, loc);
 640                                 }
 641                         }
 642
 643                         if (ArrayParameter != null){
 644                                 ParameterBuilder pb;
 645                                 Parameter array_param = ArrayParameter;
 646
 647                                 if (mb == null)
 648                                         pb = cb.DefineParameter (
 649                                                 i + 1, array_param.Attributes,
 650                                                 array_param.Name);
 651                                 else
 652                                         pb = mb.DefineParameter (
 653                                                 i + 1, array_param.Attributes,
 654                                                 array_param.Name);
 655
 656                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 657                                         TypeManager.cons_param_array_attribute, new object [0]);
 658
 659                                 pb.SetCustomAttribute (a);
 660                         }
 661                 }
 662         }
 663 }