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_T (-24, a.Location);
  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_T (-28, location);
  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                 protected 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                 protected 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                 // <summary>
 154                 //   Resolve is used in method definitions
 155                 // </summary>
 156                 public bool Resolve (DeclSpace ds, Location l)
 157                 {
 158                         TypeExpr texpr = ds.ResolveTypeExpr (TypeName, false, l);
 159                         if (texpr == null)
 160                                 return false;
 161
 162                         TypeParameterExpr tparam = texpr as TypeParameterExpr;
 163                         if (tparam != null)
 164                                 constraints = tparam.TypeParameter.Constraints;
 165
 166                         parameter_type = ds.ResolveType (texpr, l);
 167
 168                         if (parameter_type == TypeManager.void_type){
 169                                 Report.Error (1536, l, "`void' parameter is not permitted");
 170                                 return false;
 171                         }
 172
 173                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 174                                 if (parameter_type == TypeManager.typed_reference_type ||
 175                                     parameter_type == TypeManager.arg_iterator_type){
 176                                         Report.Error (1601, l,
 177                                                       "out or ref parameter can not be of type TypedReference or ArgIterator");
 178                                         return false;
 179                                 }
 180                         }
 181
 182                         return parameter_type != null;
 183                 }
 184
 185                 public Type ExternalType ()
 186                 {
 187                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 188                                 return TypeManager.GetReferenceType (parameter_type);
 189
 190                         return parameter_type;
 191                 }
 192
 193                 public Type ParameterType {
 194                         get {
 195                                 return parameter_type;
 196                         }
 197                 }
 198
 199                 public GenericConstraints GenericConstraints {
 200                         get {
 201                                 return constraints;
 202                         }
 203                 }
 204
 205                 public ParameterAttributes Attributes {
 206                         get {
 207                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 208                                 switch ((Modifier) flags) {
 209                                 case Modifier.NONE:
 210                                         return ParameterAttributes.None;
 211                                 case Modifier.REF:
 212                                         return ParameterAttributes.None;
 213                                 case Modifier.OUT:
 214                                         return ParameterAttributes.Out;
 215                                 case Modifier.PARAMS:
 216                                         return 0;
 217                                 }
 218
 219                                 return ParameterAttributes.None;
 220                         }
 221                 }
 222
 223                 public override AttributeTargets AttributeTargets {
 224                         get {
 225                                 return AttributeTargets.Parameter;
 226                         }
 227                 }
 228
 229                 /// <summary>
 230                 ///   Returns the signature for this parameter evaluating it on the
 231                 ///   @tc context
 232                 /// </summary>
 233                 public string GetSignature (DeclSpace ds, Location loc)
 234                 {
 235                         if (parameter_type == null){
 236                                 if (!Resolve (ds, loc))
 237                                         return null;
 238                         }
 239
 240                         return ExternalType ().FullName;
 241                 }
 242
 243                 public string GetSignatureForError ()
 244                 {
 245                         string typeName = TypeManager.CSharpName (parameter_type);
 246                         switch (ModFlags & ~Modifier.ISBYREF) {
 247                                 case Modifier.OUT:
 248                                         return "out " + typeName;
 249                                 case Modifier.PARAMS:
 250                                         return "params " + typeName;
 251                                 case Modifier.REF:
 252                                         return "ref " + typeName;
 253                         }
 254                         return typeName;
 255                 }
 256
 257                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index, Location loc)
 258                 {
 259                         ParameterAttributes par_attr = Attributes;
 260
 261                         if (mb == null)
 262                                 builder = cb.DefineParameter (index, par_attr, Name);
 263                         else
 264                                 builder = mb.DefineParameter (index, par_attr, Name);
 265
 266                         if (OptAttributes != null) {
 267                                 OptAttributes.Emit (ec, this);
 268
 269                                 if (par_attr == ParameterAttributes.Out){
 270                                         if (OptAttributes.Contains (TypeManager.in_attribute_type, ec))
 271                                                 Report.Error (36, loc,  "Can not use [In] attribute on out parameter");
 272                                 }
 273                         }
 274                 }
 275
 276                 protected override string[] ValidAttributeTargets {
 277                         get {
 278                                 return attribute_targets;
 279                         }
 280                 }
 281         }
 282
 283         /// <summary>
 284         ///   Represents the methods parameters
 285         /// </summary>
 286         public class Parameters {
 287                 public Parameter [] FixedParameters;
 288                 public readonly Parameter ArrayParameter;
 289                 public readonly bool HasArglist;
 290                 string signature;
 291                 Type [] types;
 292                 Location loc;
 293
 294                 static Parameters empty_parameters;
 295
 296                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 297                 {
 298                         FixedParameters = fixed_parameters;
 299                         ArrayParameter  = array_parameter;
 300                         loc = l;
 301                 }
 302
 303                 public Parameters (Parameter [] fixed_parameters, bool has_arglist, Location l)
 304                 {
 305                         FixedParameters = fixed_parameters;
 306                         HasArglist = has_arglist;
 307                         loc = l;
 308                 }
 309
 310                 /// <summary>
 311                 ///   This is used to reuse a set of empty parameters, because they
 312                 ///   are common
 313                 /// </summary>
 314                 public static Parameters EmptyReadOnlyParameters {
 315                         get {
 316                                 if (empty_parameters == null)
 317                                         empty_parameters = new Parameters (null, null, Location.Null);
 318
 319                                 return empty_parameters;
 320                         }
 321                 }
 322
 323                 public bool Empty {
 324                         get {
 325                                 return (FixedParameters == null) && (ArrayParameter == null);
 326                         }
 327                 }
 328
 329                 public void ComputeSignature (DeclSpace ds)
 330                 {
 331                         signature = "";
 332                         if (FixedParameters != null){
 333                                 for (int i = 0; i < FixedParameters.Length; i++){
 334                                         Parameter par = FixedParameters [i];
 335
 336                                         signature += par.GetSignature (ds, loc);
 337                                 }
 338                         }
 339                         //
 340                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 341                         // are not used in the signature computation for a method
 342                         //
 343                 }
 344
 345                 void Error_DuplicateParameterName (string name)
 346                 {
 347                         Report.Error (
 348                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 349                 }
 350
 351                 public bool VerifyArgs ()
 352                 {
 353                         int count;
 354                         int i, j;
 355
 356                         if (FixedParameters == null)
 357                                 return true;
 358
 359                         count = FixedParameters.Length;
 360                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 361                         for (i = 0; i < count; i++){
 362                                 string base_name = FixedParameters [i].Name;
 363
 364                                 for (j = i + 1; j < count; j++){
 365                                         if (base_name != FixedParameters [j].Name)
 366                                                 continue;
 367                                         Error_DuplicateParameterName (base_name);
 368                                         return false;
 369                                 }
 370
 371                                 if (base_name == array_par_name){
 372                                         Error_DuplicateParameterName (base_name);
 373                                         return false;
 374                                 }
 375                         }
 376                         return true;
 377                 }
 378
 379                 /// <summary>
 380                 ///    Returns the signature of the Parameters evaluated in
 381                 ///    the @tc environment
 382                 /// </summary>
 383                 public string GetSignature (DeclSpace ds)
 384                 {
 385                         if (signature == null){
 386                                 VerifyArgs ();
 387                                 ComputeSignature (ds);
 388                         }
 389
 390                         return signature;
 391                 }
 392
 393                 /// <summary>
 394                 ///    Returns the paramenter information based on the name
 395                 /// </summary>
 396                 public Parameter GetParameterByName (string name, out int idx)
 397                 {
 398                         idx = 0;
 399                         int i = 0;
 400
 401                         if (FixedParameters != null){
 402                                 foreach (Parameter par in FixedParameters){
 403                                         if (par.Name == name){
 404                                                 idx = i;
 405                                                 return par;
 406                                         }
 407                                         i++;
 408                                 }
 409                         }
 410
 411                         if (ArrayParameter != null){
 412                                 if (name == ArrayParameter.Name){
 413                                         idx = i;
 414                                         return ArrayParameter;
 415                                 }
 416                         }
 417
 418                         return null;
 419                 }
 420
 421                 bool ComputeParameterTypes (DeclSpace ds)
 422                 {
 423                         int extra = (ArrayParameter != null) ? 1 : 0;
 424                         int i = 0;
 425                         int pc;
 426
 427                         if (FixedParameters == null)
 428                                 pc = extra;
 429                         else
 430                                 pc = extra + FixedParameters.Length;
 431
 432                         types = new Type [pc];
 433
 434                         if (!VerifyArgs ()){
 435                                 FixedParameters = null;
 436                                 return false;
 437                         }
 438
 439                         bool failed = false;
 440                         if (FixedParameters != null){
 441                                 foreach (Parameter p in FixedParameters){
 442                                         Type t = null;
 443
 444                                         if (p.Resolve (ds, loc))
 445                                                 t = p.ExternalType ();
 446                                         else
 447                                                 failed = true;
 448
 449                                         types [i] = t;
 450                                         i++;
 451                                 }
 452                         }
 453
 454                         if (extra > 0){
 455                                 if (ArrayParameter.Resolve (ds, loc))
 456                                         types [i] = ArrayParameter.ExternalType ();
 457                                 else
 458                                         failed = true;
 459                         }
 460
 461                         if (failed){
 462                                 types = null;
 463                                 return false;
 464                         }
 465
 466                         return true;
 467                 }
 468
 469                 //
 470                 // This variant is used by Delegates, because they need to
 471                 // resolve/define names, instead of the plain LookupType
 472                 //
 473                 public bool ComputeAndDefineParameterTypes (DeclSpace ds)
 474                 {
 475                         int extra = (ArrayParameter != null) ? 1 : 0;
 476                         int i = 0;
 477                         int pc;
 478
 479                         if (FixedParameters == null)
 480                                 pc = extra;
 481                         else
 482                                 pc = extra + FixedParameters.Length;
 483
 484                         types = new Type [pc];
 485
 486                         if (!VerifyArgs ()){
 487                                 FixedParameters = null;
 488                                 return false;
 489                         }
 490
 491                         bool ok_flag = true;
 492
 493                         if (FixedParameters != null){
 494                                 foreach (Parameter p in FixedParameters){
 495                                         Type t = null;
 496
 497                                         if (p.Resolve (ds, loc))
 498                                                 t = p.ExternalType ();
 499                                         else
 500                                                 ok_flag = false;
 501
 502                                         types [i] = t;
 503                                         i++;
 504                                 }
 505                         }
 506
 507                         if (extra > 0){
 508                                 if (ArrayParameter.Resolve (ds, loc))
 509                                         types [i] = ArrayParameter.ExternalType ();
 510                                 else
 511                                         ok_flag = false;
 512                         }
 513
 514                         //
 515                         // invalidate the cached types
 516                         //
 517                         if (!ok_flag){
 518                                 types = null;
 519                         }
 520
 521                         return ok_flag;
 522                 }
 523
 524                 /// <summary>
 525                 ///   Returns the argument types as an array
 526                 /// </summary>
 527                 static Type [] no_types = new Type [0];
 528
 529                 public Type [] GetParameterInfo (DeclSpace ds)
 530                 {
 531                         if (types != null)
 532                                 return types;
 533
 534                         if (FixedParameters == null && ArrayParameter == null)
 535                                 return no_types;
 536
 537                         if (ComputeParameterTypes (ds) == false){
 538                                 types = null;
 539                                 return null;
 540                         }
 541
 542                         return types;
 543                 }
 544
 545                 /// <summary>
 546                 ///   Returns the type of a given parameter, and stores in the `is_out'
 547                 ///   boolean whether this is an out or ref parameter.
 548                 ///
 549                 ///   Note that the returned type will not contain any dereference in this
 550                 ///   case (ie, you get "int" for a ref int instead of "int&"
 551                 /// </summary>
 552                 public Type GetParameterInfo (DeclSpace ds, int idx, out Parameter.Modifier mod)
 553                 {
 554                         mod = Parameter.Modifier.NONE;
 555
 556                         if (!VerifyArgs ()){
 557                                 FixedParameters = null;
 558                                 return null;
 559                         }
 560
 561                         if (FixedParameters == null && ArrayParameter == null)
 562                                 return null;
 563
 564                         if (types == null)
 565                                 if (ComputeParameterTypes (ds) == false)
 566                                         return null;
 567
 568                         //
 569                         // If this is a request for the variable lenght arg.
 570                         //
 571                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 572                         if (idx == array_idx)
 573                                 return types [idx];
 574
 575                         //
 576                         // Otherwise, it is a fixed parameter
 577                         //
 578                         Parameter p = FixedParameters [idx];
 579                         mod = p.ModFlags;
 580
 581                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 582                                 mod |= Parameter.Modifier.ISBYREF;
 583
 584                         return p.ParameterType;
 585                 }
 586
 587                 public CallingConventions GetCallingConvention ()
 588                 {
 589                         if (HasArglist)
 590                                 return CallingConventions.VarArgs;
 591                         else
 592                         return CallingConventions.Standard;
 593                 }
 594
 595                 //
 596                 // The method's attributes are passed in because we need to extract
 597                 // the "return:" attribute from there to apply on the return type
 598                 //
 599                 public void LabelParameters (EmitContext ec,
 600                         MethodBase builder,
 601                         Location loc) {
 602                         //
 603                         // Define each type attribute (in/out/ref) and
 604                         // the argument names.
 605                         //
 606                         int i = 0;
 607
 608                         MethodBuilder mb = builder as MethodBuilder;
 609                         ConstructorBuilder cb = builder as ConstructorBuilder;
 610
 611                         if (FixedParameters != null) {
 612                                 for (i = 0; i < FixedParameters.Length; i++) {
 613                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1, loc);
 614                                 }
 615                         }
 616
 617                         if (ArrayParameter != null){
 618                                 ParameterBuilder pb;
 619                                 Parameter array_param = ArrayParameter;
 620
 621                                 if (mb == null)
 622                                         pb = cb.DefineParameter (
 623                                                 i + 1, array_param.Attributes,
 624                                                 array_param.Name);
 625                                 else
 626                                         pb = mb.DefineParameter (
 627                                                 i + 1, array_param.Attributes,
 628                                                 array_param.Name);
 629
 630                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 631                                         TypeManager.cons_param_array_attribute, new object [0]);
 632
 633                                 pb.SetCustomAttribute (a);
 634                         }
 635                 }
 636         }
 637 }