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                 }
 135
 136                 static string[] attribute_targets = new string [] { "param" };
 137
 138                 public readonly Expression TypeName;
 139                 public readonly Modifier ModFlags;
 140                 public readonly string Name;
 141                 GenericConstraints constraints;
 142                 Type parameter_type;
 143
 144                 public Parameter (Expression type, string name, Modifier mod, Attributes attrs)
 145                         : base (attrs)
 146                 {
 147                         Name = name;
 148                         ModFlags = mod;
 149                         TypeName = type;
 150                 }
 151
 152                 // <summary>
 153                 //   Resolve is used in method definitions
 154                 // </summary>
 155                 public bool Resolve (DeclSpace ds, Location l)
 156                 {
 157                         TypeExpr texpr = ds.ResolveTypeExpr (TypeName, false, l);
 158                         if (texpr == null)
 159                                 return false;
 160
 161                         TypeParameterExpr tparam = texpr as TypeParameterExpr;
 162                         if (tparam != null)
 163                                 constraints = tparam.TypeParameter.Constraints;
 164
 165                         parameter_type = ds.ResolveType (texpr, l);
 166
 167                         if (parameter_type == TypeManager.void_type){
 168                                 Report.Error (1536, l, "`void' parameter is not permitted");
 169                                 return false;
 170                         }
 171
 172                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0){
 173                                 if (parameter_type == TypeManager.typed_reference_type ||
 174                                     parameter_type == TypeManager.arg_iterator_type){
 175                                         Report.Error (1601, l,
 176                                                       "out or ref parameter can not be of type TypedReference or ArgIterator");
 177                                         return false;
 178                                 }
 179                         }
 180
 181                         return parameter_type != null;
 182                 }
 183
 184                 public Type ExternalType ()
 185                 {
 186                         if ((ModFlags & Parameter.Modifier.ISBYREF) != 0)
 187                                 return TypeManager.GetReferenceType (parameter_type);
 188
 189                         return parameter_type;
 190                 }
 191
 192                 public Type ParameterType {
 193                         get {
 194                                 return parameter_type;
 195                         }
 196                 }
 197
 198                 public GenericConstraints GenericConstraints {
 199                         get {
 200                                 return constraints;
 201                         }
 202                 }
 203
 204                 public ParameterAttributes Attributes {
 205                         get {
 206                                 int flags = ((int) ModFlags) & ~((int) Parameter.Modifier.ISBYREF);
 207                                 switch ((Modifier) flags) {
 208                                 case Modifier.NONE:
 209                                         return ParameterAttributes.None;
 210                                 case Modifier.REF:
 211                                         return ParameterAttributes.None;
 212                                 case Modifier.OUT:
 213                                         return ParameterAttributes.Out;
 214                                 case Modifier.PARAMS:
 215                                         return 0;
 216                                 }
 217
 218                                 return ParameterAttributes.None;
 219                         }
 220                 }
 221
 222                 public override AttributeTargets AttributeTargets {
 223                         get {
 224                                 return AttributeTargets.Parameter;
 225                         }
 226                 }
 227
 228                 /// <summary>
 229                 ///   Returns the signature for this parameter evaluating it on the
 230                 ///   @tc context
 231                 /// </summary>
 232                 public string GetSignature (DeclSpace ds, Location loc)
 233                 {
 234                         if (parameter_type == null){
 235                                 if (!Resolve (ds, loc))
 236                                         return null;
 237                         }
 238
 239                         return ExternalType ().FullName;
 240                 }
 241
 242                 public string GetSignatureForError ()
 243                 {
 244                         string typeName = TypeManager.CSharpName (parameter_type);
 245                         switch (ModFlags & ~Modifier.ISBYREF) {
 246                                 case Modifier.OUT:
 247                                         return "out " + typeName;
 248                                 case Modifier.PARAMS:
 249                                         return "params " + typeName;
 250                                 case Modifier.REF:
 251                                         return "ref " + typeName;
 252                         }
 253                         return typeName;
 254                 }
 255
 256                 public void DefineParameter (EmitContext ec, MethodBuilder mb, ConstructorBuilder cb, int index, Location loc)
 257                 {
 258                         ParameterAttributes par_attr = Attributes;
 259
 260                         if (mb == null)
 261                                 builder = cb.DefineParameter (index, par_attr, Name);
 262                         else
 263                                 builder = mb.DefineParameter (index, par_attr, Name);
 264
 265                         if (OptAttributes != null) {
 266                                 OptAttributes.Emit (ec, this);
 267
 268                                 if (par_attr == ParameterAttributes.Out){
 269                                         if (OptAttributes.Contains (TypeManager.in_attribute_type, ec))
 270                                                 Report.Error (36, loc,  "Can not use [In] attribute on out parameter");
 271                                 }
 272                         }
 273                 }
 274
 275                 protected override string[] ValidAttributeTargets {
 276                         get {
 277                                 return attribute_targets;
 278                         }
 279                 }
 280         }
 281
 282         /// <summary>
 283         ///   Represents the methods parameters
 284         /// </summary>
 285         public class Parameters {
 286                 public Parameter [] FixedParameters;
 287                 public readonly Parameter ArrayParameter;
 288                 string signature;
 289                 Type [] types;
 290                 Location loc;
 291
 292                 static Parameters empty_parameters;
 293
 294                 public Parameters (Parameter [] fixed_parameters, Parameter array_parameter, Location l)
 295                 {
 296                         FixedParameters = fixed_parameters;
 297                         ArrayParameter  = array_parameter;
 298                         loc = l;
 299                 }
 300
 301                 /// <summary>
 302                 ///   This is used to reuse a set of empty parameters, because they
 303                 ///   are common
 304                 /// </summary>
 305                 public static Parameters EmptyReadOnlyParameters {
 306                         get {
 307                                 if (empty_parameters == null)
 308                                         empty_parameters = new Parameters (null, null, Location.Null);
 309
 310                                 return empty_parameters;
 311                         }
 312                 }
 313
 314                 public bool Empty {
 315                         get {
 316                                 return (FixedParameters == null) && (ArrayParameter == null);
 317                         }
 318                 }
 319
 320                 public void ComputeSignature (DeclSpace ds)
 321                 {
 322                         signature = "";
 323                         if (FixedParameters != null){
 324                                 for (int i = 0; i < FixedParameters.Length; i++){
 325                                         Parameter par = FixedParameters [i];
 326
 327                                         signature += par.GetSignature (ds, loc);
 328                                 }
 329                         }
 330                         //
 331                         // Note: as per the spec, the `params' arguments (ArrayParameter)
 332                         // are not used in the signature computation for a method
 333                         //
 334                 }
 335
 336                 void Error_DuplicateParameterName (string name)
 337                 {
 338                         Report.Error (
 339                                 100, loc, "The parameter name `" + name + "' is a duplicate");
 340                 }
 341
 342                 public bool VerifyArgs ()
 343                 {
 344                         int count;
 345                         int i, j;
 346
 347                         if (FixedParameters == null)
 348                                 return true;
 349
 350                         count = FixedParameters.Length;
 351                         string array_par_name = ArrayParameter != null ? ArrayParameter.Name : null;
 352                         for (i = 0; i < count; i++){
 353                                 string base_name = FixedParameters [i].Name;
 354
 355                                 for (j = i + 1; j < count; j++){
 356                                         if (base_name != FixedParameters [j].Name)
 357                                                 continue;
 358                                         Error_DuplicateParameterName (base_name);
 359                                         return false;
 360                                 }
 361
 362                                 if (base_name == array_par_name){
 363                                         Error_DuplicateParameterName (base_name);
 364                                         return false;
 365                                 }
 366                         }
 367                         return true;
 368                 }
 369
 370                 /// <summary>
 371                 ///    Returns the signature of the Parameters evaluated in
 372                 ///    the @tc environment
 373                 /// </summary>
 374                 public string GetSignature (DeclSpace ds)
 375                 {
 376                         if (signature == null){
 377                                 VerifyArgs ();
 378                                 ComputeSignature (ds);
 379                         }
 380
 381                         return signature;
 382                 }
 383
 384                 /// <summary>
 385                 ///    Returns the paramenter information based on the name
 386                 /// </summary>
 387                 public Parameter GetParameterByName (string name, out int idx)
 388                 {
 389                         idx = 0;
 390                         int i = 0;
 391
 392                         if (FixedParameters != null){
 393                                 foreach (Parameter par in FixedParameters){
 394                                         if (par.Name == name){
 395                                                 idx = i;
 396                                                 return par;
 397                                         }
 398                                         i++;
 399                                 }
 400                         }
 401
 402                         if (ArrayParameter != null){
 403                                 if (name == ArrayParameter.Name){
 404                                         idx = i;
 405                                         return ArrayParameter;
 406                                 }
 407                         }
 408
 409                         return null;
 410                 }
 411
 412                 bool ComputeParameterTypes (DeclSpace ds)
 413                 {
 414                         int extra = (ArrayParameter != null) ? 1 : 0;
 415                         int i = 0;
 416                         int pc;
 417
 418                         if (FixedParameters == null)
 419                                 pc = extra;
 420                         else
 421                                 pc = extra + FixedParameters.Length;
 422
 423                         types = new Type [pc];
 424
 425                         if (!VerifyArgs ()){
 426                                 FixedParameters = null;
 427                                 return false;
 428                         }
 429
 430                         bool failed = false;
 431                         if (FixedParameters != null){
 432                                 foreach (Parameter p in FixedParameters){
 433                                         Type t = null;
 434
 435                                         if (p.Resolve (ds, loc))
 436                                                 t = p.ExternalType ();
 437                                         else
 438                                                 failed = true;
 439
 440                                         types [i] = t;
 441                                         i++;
 442                                 }
 443                         }
 444
 445                         if (extra > 0){
 446                                 if (ArrayParameter.Resolve (ds, loc))
 447                                         types [i] = ArrayParameter.ExternalType ();
 448                                 else
 449                                         failed = true;
 450                         }
 451
 452                         if (failed){
 453                                 types = null;
 454                                 return false;
 455                         }
 456
 457                         return true;
 458                 }
 459
 460                 //
 461                 // This variant is used by Delegates, because they need to
 462                 // resolve/define names, instead of the plain LookupType
 463                 //
 464                 public bool ComputeAndDefineParameterTypes (DeclSpace ds)
 465                 {
 466                         int extra = (ArrayParameter != null) ? 1 : 0;
 467                         int i = 0;
 468                         int pc;
 469
 470                         if (FixedParameters == null)
 471                                 pc = extra;
 472                         else
 473                                 pc = extra + FixedParameters.Length;
 474
 475                         types = new Type [pc];
 476
 477                         if (!VerifyArgs ()){
 478                                 FixedParameters = null;
 479                                 return false;
 480                         }
 481
 482                         bool ok_flag = true;
 483
 484                         if (FixedParameters != null){
 485                                 foreach (Parameter p in FixedParameters){
 486                                         Type t = null;
 487
 488                                         if (p.Resolve (ds, loc))
 489                                                 t = p.ExternalType ();
 490                                         else
 491                                                 ok_flag = false;
 492
 493                                         types [i] = t;
 494                                         i++;
 495                                 }
 496                         }
 497
 498                         if (extra > 0){
 499                                 if (ArrayParameter.Resolve (ds, loc))
 500                                         types [i] = ArrayParameter.ExternalType ();
 501                                 else
 502                                         ok_flag = false;
 503                         }
 504
 505                         //
 506                         // invalidate the cached types
 507                         //
 508                         if (!ok_flag){
 509                                 types = null;
 510                         }
 511
 512                         return ok_flag;
 513                 }
 514
 515                 /// <summary>
 516                 ///   Returns the argument types as an array
 517                 /// </summary>
 518                 static Type [] no_types = new Type [0];
 519
 520                 public Type [] GetParameterInfo (DeclSpace ds)
 521                 {
 522                         if (types != null)
 523                                 return types;
 524
 525                         if (FixedParameters == null && ArrayParameter == null)
 526                                 return no_types;
 527
 528                         if (ComputeParameterTypes (ds) == false){
 529                                 types = null;
 530                                 return null;
 531                         }
 532
 533                         return types;
 534                 }
 535
 536                 /// <summary>
 537                 ///   Returns the type of a given parameter, and stores in the `is_out'
 538                 ///   boolean whether this is an out or ref parameter.
 539                 ///
 540                 ///   Note that the returned type will not contain any dereference in this
 541                 ///   case (ie, you get "int" for a ref int instead of "int&"
 542                 /// </summary>
 543                 public Type GetParameterInfo (DeclSpace ds, int idx, out Parameter.Modifier mod)
 544                 {
 545                         mod = Parameter.Modifier.NONE;
 546
 547                         if (!VerifyArgs ()){
 548                                 FixedParameters = null;
 549                                 return null;
 550                         }
 551
 552                         if (FixedParameters == null && ArrayParameter == null)
 553                                 return null;
 554
 555                         if (types == null)
 556                                 if (ComputeParameterTypes (ds) == false)
 557                                         return null;
 558
 559                         //
 560                         // If this is a request for the variable lenght arg.
 561                         //
 562                         int array_idx = (FixedParameters != null ? FixedParameters.Length : 0);
 563                         if (idx == array_idx)
 564                                 return types [idx];
 565
 566                         //
 567                         // Otherwise, it is a fixed parameter
 568                         //
 569                         Parameter p = FixedParameters [idx];
 570                         mod = p.ModFlags;
 571
 572                         if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) != 0)
 573                                 mod |= Parameter.Modifier.ISBYREF;
 574
 575                         return p.ParameterType;
 576                 }
 577
 578                 public CallingConventions GetCallingConvention ()
 579                 {
 580                         // For now this is the only correc thing to do
 581                         return CallingConventions.Standard;
 582                 }
 583
 584                 //
 585                 // The method's attributes are passed in because we need to extract
 586                 // the "return:" attribute from there to apply on the return type
 587                 //
 588                 public void LabelParameters (EmitContext ec,
 589                         MethodBase builder,
 590                         Location loc) {
 591                         //
 592                         // Define each type attribute (in/out/ref) and
 593                         // the argument names.
 594                         //
 595                         int i = 0;
 596
 597                         MethodBuilder mb = builder as MethodBuilder;
 598                         ConstructorBuilder cb = builder as ConstructorBuilder;
 599
 600                         if (FixedParameters != null) {
 601                                 for (i = 0; i < FixedParameters.Length; i++) {
 602                                         FixedParameters [i].DefineParameter (ec, mb, cb, i + 1, loc);
 603                                 }
 604                         }
 605
 606                         if (ArrayParameter != null){
 607                                 ParameterBuilder pb;
 608                                 Parameter array_param = ArrayParameter;
 609
 610                                 if (mb == null)
 611                                         pb = cb.DefineParameter (
 612                                                 i + 1, array_param.Attributes,
 613                                                 array_param.Name);
 614                                 else
 615                                         pb = mb.DefineParameter (
 616                                                 i + 1, array_param.Attributes,
 617                                                 array_param.Name);
 618
 619                                 CustomAttributeBuilder a = new CustomAttributeBuilder (
 620                                         TypeManager.cons_param_array_attribute, new object [0]);
 621
 622                                 pb.SetCustomAttribute (a);
 623                         }
 624                 }
 625         }
 626 }