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