mcs/mbas/codegen.cs

   1 //
   2 // codegen.cs: The code generator
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001 Ximian, Inc.
   8 //
   9
  10 using System;
  11 using System.IO;
  12 using System.Collections;
  13 using System.Reflection;
  14 using System.Reflection.Emit;
  15 using System.Diagnostics.SymbolStore;
  16
  17 namespace Mono.MonoBASIC {
  18
  19         /// <summary>
  20         ///    Code generator class.
  21         /// </summary>
  22         public class CodeGen {
  23                 static AppDomain current_domain;
  24
  25                 public static AssemblyBuilder AssemblyBuilder {
  26                         get {
  27                                 return Assembly.Builder;
  28                         }
  29
  30                         set {
  31                                 Assembly.Builder = value;
  32                         }
  33                 }
  34
  35                 public static ModuleBuilder ModuleBuilder {
  36                         get {
  37                                 return Module.Builder;
  38                         }
  39
  40                         set {
  41                                 Module.Builder = value;
  42                         }
  43                 }
  44
  45                 public static AssemblyClass Assembly;
  46                 public static ModuleClass Module;
  47
  48                 static public ISymbolWriter SymbolWriter;
  49
  50                 static CodeGen ()
  51                 {
  52                         Assembly = new AssemblyClass ();
  53                         Module = new ModuleClass ();
  54                 }
  55
  56                 public static string Basename (string name)
  57                 {
  58                         int pos = name.LastIndexOf ("/");
  59
  60                         if (pos != -1)
  61                                 return name.Substring (pos + 1);
  62
  63                         pos = name.LastIndexOf ("\\");
  64                         if (pos != -1)
  65                                 return name.Substring (pos + 1);
  66
  67                         return name;
  68                 }
  69
  70                 public static string Dirname (string name)
  71                 {
  72                         int pos = name.LastIndexOf ("/");
  73
  74                         if (pos != -1)
  75                                 return name.Substring (0, pos);
  76
  77                         pos = name.LastIndexOf ("\\");
  78                         if (pos != -1)
  79                                 return name.Substring (0, pos);
  80
  81                         return ".";
  82                 }
  83
  84                 static string TrimExt (string name)
  85                 {
  86                         int pos = name.LastIndexOf (".");
  87
  88                         return name.Substring (0, pos);
  89                 }
  90
  91                 static public string FileName;
  92
  93                 //
  94                 // This routine initializes the Mono runtime SymbolWriter.
  95                 //
  96                 static bool InitMonoSymbolWriter (string basename, string symbol_output,
  97                                                   string exe_output_file, string[] debug_args)
  98                 {
  99                         Type itype = SymbolWriter.GetType ();
 100                         if (itype == null)
 101                                 return false;
 102
 103                         Type[] arg_types = new Type [3];
 104                         arg_types [0] = typeof (string);
 105                         arg_types [1] = typeof (string);
 106                         arg_types [2] = typeof (string[]);
 107
 108                         MethodInfo initialize = itype.GetMethod ("Initialize", arg_types);
 109                         if (initialize == null)
 110                                 return false;
 111
 112                         object[] args = new object [3];
 113                         args [0] = exe_output_file;
 114                         args [1] = symbol_output;
 115                         args [2] = debug_args;
 116
 117                         initialize.Invoke (SymbolWriter, args);
 118                         return true;
 119                 }
 120
 121                 //
 122                 // Initializes the symbol writer
 123                 //
 124                 static void InitializeSymbolWriter (string basename, string symbol_output,
 125                                                     string exe_output_file, string[] args)
 126                 {
 127                         SymbolWriter = ModuleBuilder.GetSymWriter ();
 128
 129                         //
 130                         // If we got an ISymbolWriter instance, initialize it.
 131                         //
 132                         if (SymbolWriter == null) {
 133                                 Report.Warning (
 134                                         -18, "Cannot find any symbol writer");
 135                                 return;
 136                         }
 137
 138                         //
 139                         // Due to lacking documentation about the first argument of the
 140                         // Initialize method, we cannot use Microsoft's default symbol
 141                         // writer yet.
 142                         //
 143                         // If we're using the mono symbol writer, the SymbolWriter object
 144                         // is of type MonoSymbolWriter - but that's defined in a dynamically
 145                         // loaded DLL - that's why we're doing a comparision based on the type
 146                         // name here instead of using `SymbolWriter is MonoSymbolWriter'.
 147                         //
 148                         Type sym_type = ((object) SymbolWriter).GetType ();
 149
 150                         switch (sym_type.Name){
 151                         case "MonoSymbolWriter":
 152                                 if (!InitMonoSymbolWriter (basename, symbol_output,
 153                                                            exe_output_file, args))
 154                                         Report.Warning (
 155                                                 -18, "Cannot initialize the symbol writer");
 156                                 break;
 157
 158                         default:
 159                                 Report.Warning (
 160                                         -18, "Cannot generate debugging information on this platform");
 161                                 break;
 162                         }
 163                 }
 164
 165                 //
 166                 // Initializes the code generator variables
 167                 //
 168                 static public void Init (string name, string output, bool want_debugging_support,
 169                                          string[] debug_args)
 170                 {
 171                         AssemblyName an;
 172
 173                         FileName = output;
 174                         an = new AssemblyName ();
 175                         an.Name = TrimExt (Basename (name));
 176                         current_domain = AppDomain.CurrentDomain;
 177                         AssemblyBuilder = current_domain.DefineDynamicAssembly (
 178                                 an, AssemblyBuilderAccess.RunAndSave, Dirname (name));
 179
 180                         //
 181                         // Pass a path-less name to DefineDynamicModule.  Wonder how
 182                         // this copes with output in different directories then.
 183                         // FIXME: figure out how this copes with --output /tmp/blah
 184                         //
 185                         // If the third argument is true, the ModuleBuilder will dynamically
 186                         // load the default symbol writer.
 187                         //
 188                         ModuleBuilder = AssemblyBuilder.DefineDynamicModule (
 189                                 Basename (name), Basename (output), want_debugging_support);
 190
 191                         int pos = output.LastIndexOf (".");
 192
 193                         string basename;
 194                         if (pos > 0)
 195                                 basename = output.Substring (0, pos);
 196                         else
 197                                 basename = output;
 198
 199                         string symbol_output = basename + ".dbg";
 200
 201                         if (want_debugging_support)
 202                                 InitializeSymbolWriter (basename, symbol_output, output, debug_args);
 203                         else {
 204                                 try {
 205                                         File.Delete (symbol_output);
 206                                 } catch {
 207                                         // Ignore errors.
 208                                 }
 209                         }
 210                 }
 211
 212                 static public void Save (string name)
 213                 {
 214                         try {
 215                                 AssemblyBuilder.Save (Basename (name));
 216                         } catch (System.IO.IOException io){
 217                                 Report.Error (16, "Coult not write to file `"+name+"', cause: " + io.Message);
 218                         }
 219                 }
 220
 221                 static public void SaveSymbols ()
 222                 {
 223                         if (SymbolWriter != null) {
 224                                 // If we have a symbol writer, call its Close() method to write
 225                                 // the symbol file to disk.
 226                                 //
 227                                 // When using Mono's default symbol writer, the Close() method must
 228                                 // be called after the assembly has already been written to disk since
 229                                 // it opens the assembly and reads its metadata.
 230                                 SymbolWriter.Close ();
 231                         }
 232                 }
 233
 234                 public static void AddGlobalAttributes (ArrayList attrs)
 235                 {
 236                         foreach (Attribute attr in attrs) {
 237                                 if (attr.IsAssemblyAttribute)
 238                                         Assembly.AddAttribute (attr);
 239                                 else if (attr.IsModuleAttribute)
 240                                         Module.AddAttribute (attr);
 241                         }
 242                 }
 243
 244                 public static void EmitGlobalAttributes ()
 245                 {
 246                         //Assembly.Emit (Tree.Types);
 247                         //Module.Emit (Tree.Types);
 248
 249                 }
 250         }
 251
 252         /// <summary>
 253         ///   An Emit Context is created for each body of code (from methods,
 254         ///   properties bodies, indexer bodies or constructor bodies)
 255         /// </summary>
 256         public class EmitContext {
 257                 public DeclSpace DeclSpace;
 258                 public TypeContainer TypeContainer;
 259                 public ILGenerator   ig;
 260
 261                 /// <summary>
 262                 ///   This variable tracks the `checked' state of the compilation,
 263                 ///   it controls whether we should generate code that does overflow
 264                 ///   checking, or if we generate code that ignores overflows.
 265                 ///
 266                 ///   The default setting comes from the command line option to generate
 267                 ///   checked or unchecked code plus any source code changes using the
 268                 ///   checked/unchecked statements or expressions.   Contrast this with
 269                 ///   the ConstantCheckState flag.
 270                 /// </summary>
 271
 272                 public bool CheckState;
 273
 274                 /// <summary>
 275                 ///   The constant check state is always set to `true' and cant be changed
 276                 ///   from the command line.  The source code can change this setting with
 277                 ///   the `checked' and `unchecked' statements and expressions.
 278                 /// </summary>
 279                 public bool ConstantCheckState;
 280
 281                 /// <summary>
 282                 ///   Whether we are emitting code inside a static or instance method
 283                 /// </summary>
 284                 public bool IsStatic;
 285
 286                 /// <summary>
 287                 ///   Whether we are emitting a field initializer
 288                 /// </summary>
 289                 public bool IsFieldInitializer;
 290
 291                 /// <summary>
 292                 ///   The value that is allowed to be returned or NULL if there is no
 293                 ///   return type.
 294                 /// </summary>
 295                 public Type ReturnType;
 296
 297                 /// <summary>
 298                 ///   Points to the Type (extracted from the TypeContainer) that
 299                 ///   declares this body of code
 300                 /// </summary>
 301                 public Type ContainerType;
 302
 303                 /// <summary>
 304                 ///   Whether this is generating code for a constructor
 305                 /// </summary>
 306                 public bool IsConstructor;
 307
 308                 /// <summary>
 309                 ///   Whether we're control flow analysis enabled
 310                 /// </summary>
 311                 public bool DoFlowAnalysis;
 312
 313                 /// <summary>
 314                 ///   Keeps track of the Type to LocalBuilder temporary storage created
 315                 ///   to store structures (used to compute the address of the structure
 316                 ///   value on structure method invocations)
 317                 /// </summary>
 318                 public Hashtable temporary_storage;
 319
 320                 public Block CurrentBlock;
 321
 322                 /// <summary>
 323                 ///   The location where we store the return value.
 324                 /// </summary>
 325                 LocalBuilder return_value;
 326
 327                 /// <summary>
 328                 ///   The location where return has to jump to return the
 329                 ///   value
 330                 /// </summary>
 331                 public Label ReturnLabel;
 332
 333                 /// <summary>
 334                 ///   If we already defined the ReturnLabel
 335                 /// </summary>
 336                 public bool HasReturnLabel;
 337
 338                 /// <summary>
 339                 ///   Whether we are in a Finally block
 340                 /// </summary>
 341                 public bool InFinally;
 342
 343                 /// <summary>
 344                 ///   Whether we are in a Try block
 345                 /// </summary>
 346                 public bool InTry;
 347
 348                 /// <summary>
 349                 ///   Whether we are in a Catch block
 350                 /// </summary>
 351                 public bool InCatch;
 352
 353                 /// <summary>
 354                 ///  Whether we are inside an unsafe block
 355                 /// </summary>
 356                 public bool InUnsafe;
 357
 358                 /// <summary>
 359                 ///  Whether we are inside an unsafe block
 360                 /// </summary>
 361                 public bool InvokingOwnOverload;
 362
 363                 /// <summary>
 364                 ///   Location for this EmitContext
 365                 /// </summary>
 366                 public Location loc;
 367
 368                 /// <summary>
 369                 ///   Used to flag that it is ok to define types recursively, as the
 370                 ///   expressions are being evaluated as part of the type lookup
 371                 ///   during the type resolution process
 372                 /// </summary>
 373                 public bool ResolvingTypeTree;
 374
 375                 /// <summary>
 376                 ///   Inside an enum definition, we do not resolve enumeration values
 377                 ///   to their enumerations, but rather to the underlying type/value
 378                 ///   This is so EnumVal + EnumValB can be evaluated.
 379                 ///
 380                 ///   There is no "E operator + (E x, E y)", so during an enum evaluation
 381                 ///   we relax the rules
 382                 /// </summary>
 383                 public bool InEnumContext;
 384
 385                 public string BlockName;
 386
 387                 protected Stack FlowStack;
 388
 389                 public EmitContext (TypeContainer parent, DeclSpace ds, Location l, ILGenerator ig,
 390                                     Type return_type, int code_flags, bool is_constructor)
 391                 {
 392                         this.ig = ig;
 393
 394                         TypeContainer = parent;
 395                         DeclSpace = ds;
 396                         CheckState = RootContext.Checked;
 397                         ConstantCheckState = true;
 398
 399                         IsStatic = (code_flags & Modifiers.STATIC) != 0;
 400                         ReturnType = return_type;
 401                         IsConstructor = is_constructor;
 402                         CurrentBlock = null;
 403                         BlockName = "";
 404                         InvokingOwnOverload = false;
 405
 406                         if (parent != null){
 407                                 // Can only be null for the ResolveType contexts.
 408                                 ContainerType = parent.TypeBuilder;
 409                                 if (parent.UnsafeContext)
 410                                         InUnsafe = true;
 411                                 else
 412                                         InUnsafe = (code_flags & Modifiers.UNSAFE) != 0;
 413                         }
 414                         loc = l;
 415
 416                         FlowStack = new Stack ();
 417
 418                         if (ReturnType == TypeManager.void_type)
 419                                 ReturnType = null;
 420                 }
 421
 422                 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
 423                                     Type return_type, int code_flags, bool is_constructor)
 424                         : this (tc, tc, l, ig, return_type, code_flags, is_constructor)
 425                 {
 426                 }
 427
 428                 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
 429                                     Type return_type, int code_flags)
 430                         : this (tc, tc, l, ig, return_type, code_flags, false)
 431                 {
 432                 }
 433
 434                 public FlowBranching CurrentBranching {
 435                         get {
 436                                 return (FlowBranching) FlowStack.Peek ();
 437                         }
 438                 }
 439
 440                 // <summary>
 441                 //   Starts a new code branching.  This inherits the state of all local
 442                 //   variables and parameters from the current branching.
 443                 // </summary>
 444                 public FlowBranching StartFlowBranching (FlowBranchingType type, Location loc)
 445                 {
 446                         FlowBranching cfb = new FlowBranching (CurrentBranching, type, null, loc);
 447
 448                         FlowStack.Push (cfb);
 449
 450                         return cfb;
 451                 }
 452
 453                 // <summary>
 454                 //   Starts a new code branching for block `block'.
 455                 // </summary>
 456                 public FlowBranching StartFlowBranching (Block block)
 457                 {
 458                         FlowBranching cfb;
 459                         FlowBranchingType type;
 460
 461                         if (CurrentBranching.Type == FlowBranchingType.SWITCH)
 462                                 type = FlowBranchingType.SWITCH_SECTION;
 463                         else
 464                                 type = FlowBranchingType.BLOCK;
 465
 466                         cfb = new FlowBranching (CurrentBranching, type, block, block.StartLocation);
 467
 468                         FlowStack.Push (cfb);
 469
 470                         return cfb;
 471                 }
 472
 473                 // <summary>
 474                 //   Ends a code branching.  Merges the state of locals and parameters
 475                 //   from all the children of the ending branching.
 476                 // </summary>
 477                 public FlowReturns EndFlowBranching ()
 478                 {
 479                         FlowBranching cfb = (FlowBranching) FlowStack.Pop ();
 480
 481                         return CurrentBranching.MergeChild (cfb);
 482                 }
 483
 484                 // <summary>
 485                 //   Kills the current code branching.  This throws away any changed state
 486                 //   information and should only be used in case of an error.
 487                 // </summary>
 488                 public void KillFlowBranching ()
 489                 {
 490                         FlowBranching cfb = (FlowBranching) FlowStack.Pop ();
 491                 }
 492
 493                 // <summary>
 494                 //   Checks whether the local variable `vi' is already initialized
 495                 //   at the current point of the method's control flow.
 496                 //   If this method returns false, the caller must report an
 497                 //   error 165.
 498                 // </summary>
 499                 public bool IsVariableAssigned (VariableInfo vi)
 500                 {
 501                         if (DoFlowAnalysis)
 502                                 return CurrentBranching.IsVariableAssigned (vi);
 503                         else
 504                                 return true;
 505                 }
 506
 507                 // <summary>
 508                 //   Marks the local variable `vi' as being initialized at the current
 509                 //   current point of the method's control flow.
 510                 // </summary>
 511                 public void SetVariableAssigned (VariableInfo vi)
 512                 {
 513                         if (DoFlowAnalysis)
 514                                 CurrentBranching.SetVariableAssigned (vi);
 515                 }
 516
 517                 // <summary>
 518                 //   Checks whether the parameter `number' is already initialized
 519                 //   at the current point of the method's control flow.
 520                 //   If this method returns false, the caller must report an
 521                 //   error 165.  This is only necessary for `out' parameters and the
 522                 //   call will always succeed for non-`out' parameters.
 523                 // </summary>
 524                 public bool IsParameterAssigned (int number)
 525                 {
 526                         if (DoFlowAnalysis)
 527                                 return CurrentBranching.IsParameterAssigned (number);
 528                         else
 529                                 return true;
 530                 }
 531
 532                 // <summary>
 533                 //   Marks the parameter `number' as being initialized at the current
 534                 //   current point of the method's control flow.  This is only necessary
 535                 //   for `out' parameters.
 536                 // </summary>
 537                 public void SetParameterAssigned (int number)
 538                 {
 539                         if (DoFlowAnalysis)
 540                                 CurrentBranching.SetParameterAssigned (number);
 541                 }
 542
 543                 // These are two overloaded methods for EmitTopBlock
 544                 // since in MonoBasic functions we need the Function name
 545                 // along with its top block, in order to be able to
 546                 // retrieve the return value when there is no explicit
 547                 // 'Return' statement
 548                 public void EmitTopBlock (Block block, InternalParameters ip, Location loc)
 549                 {
 550                         EmitTopBlock (block, "", ip, loc);
 551                 }
 552
 553                 public void EmitTopBlock (Block block, string bname, InternalParameters ip, Location loc)
 554                 {
 555                         bool has_ret = false;
 556
 557                         //Console.WriteLine ("Emitting: '{0}", bname);
 558                         BlockName = bname;
 559                         if (CodeGen.SymbolWriter != null)
 560                                 Mark (loc);
 561
 562                         if (block != null){
 563                                 int errors = Report.Errors;
 564
 565                                 block.EmitMeta (this, block);
 566
 567                                 if (Report.Errors == errors){
 568                                         bool old_do_flow_analysis = DoFlowAnalysis;
 569                                         DoFlowAnalysis = true;
 570
 571                                         FlowBranching cfb = new FlowBranching (block, ip, loc);
 572                                         FlowStack.Push (cfb);
 573
 574                                         if (!block.Resolve (this)) {
 575                                                 FlowStack.Pop ();
 576                                                 DoFlowAnalysis = old_do_flow_analysis;
 577                                                 return;
 578                                         }
 579
 580                                         cfb = (FlowBranching) FlowStack.Pop ();
 581                                         FlowReturns returns = cfb.MergeTopBlock ();
 582
 583                                         DoFlowAnalysis = old_do_flow_analysis;
 584
 585                                         has_ret = block.Emit (this);
 586
 587                                         if ((returns == FlowReturns.ALWAYS) ||
 588                                             (returns == FlowReturns.EXCEPTION) ||
 589                                             (returns == FlowReturns.UNREACHABLE))
 590                                                 has_ret = true;
 591
 592                                         if (Report.Errors == errors){
 593                                                 if (RootContext.WarningLevel >= 3)
 594                                                         block.UsageWarning ();
 595                                         }
 596                                 }
 597                         }
 598
 599                         if (ReturnType != null && !has_ret){
 600                                 //
 601                                 // mcs here would report an error (and justly so), but functions without
 602                                 // an explicit return value are perfectly legal in MonoBasic
 603                                 //
 604
 605                                 VariableInfo vi = block.GetVariableInfo (bname);
 606                                 if (vi != null)
 607                                 {
 608                                         ig.Emit (OpCodes.Ldloc, vi.LocalBuilder);
 609                                         ig.Emit (OpCodes.Ret);
 610                                 }
 611                                 else
 612                                         Report.Error (-200, "This is not supposed to happen !");
 613                                 return;
 614                         }
 615
 616                         if (HasReturnLabel)
 617                                 ig.MarkLabel (ReturnLabel);
 618                         if (return_value != null){
 619                                 ig.Emit (OpCodes.Ldloc, return_value);
 620                                 ig.Emit (OpCodes.Ret);
 621                         } else {
 622                                 if (!InTry){
 623                                         if (!has_ret || HasReturnLabel)
 624                                                 ig.Emit (OpCodes.Ret);
 625                                 }
 626                         }
 627                 }
 628
 629                 /// <summary>
 630                 ///   This is called immediately before emitting an IL opcode to tell the symbol
 631                 ///   writer to which source line this opcode belongs.
 632                 /// </summary>
 633                 public void Mark (Location loc)
 634                 {
 635                         if ((CodeGen.SymbolWriter != null) && !Location.IsNull (loc)) {
 636                                 ISymbolDocumentWriter doc = loc.SymbolDocument;
 637
 638                                 if (doc != null)
 639                                         ig.MarkSequencePoint (doc, loc.Row, 0,  loc.Row, 0);
 640                         }
 641                 }
 642
 643                 /// <summary>
 644                 ///   Returns a temporary storage for a variable of type t as
 645                 ///   a local variable in the current body.
 646                 /// </summary>
 647                 public LocalBuilder GetTemporaryStorage (Type t)
 648                 {
 649                         LocalBuilder location;
 650
 651                         if (temporary_storage != null){
 652                                 location = (LocalBuilder) temporary_storage [t];
 653                                 if (location != null)
 654                                         return location;
 655                         }
 656
 657                         location = ig.DeclareLocal (t);
 658
 659                         return location;
 660                 }
 661
 662                 public void FreeTemporaryStorage (LocalBuilder b)
 663                 {
 664                         // Empty for now.
 665                 }
 666
 667                 /// <summary>
 668                 ///   Current loop begin and end labels.
 669                 /// </summary>
 670                 public Label LoopBegin, LoopEnd;
 671
 672                 /// <summary>
 673                 ///   Whether we are inside a loop and break/continue are possible.
 674                 /// </summary>
 675                 public bool  InLoop;
 676
 677                 /// <summary>
 678                 ///   This is incremented each time we enter a try/catch block and
 679                 ///   decremented if we leave it.
 680                 /// </summary>
 681                 public int   TryCatchLevel;
 682
 683                 /// <summary>
 684                 ///   The TryCatchLevel at the begin of the current loop.
 685                 /// </summary>
 686                 public int   LoopBeginTryCatchLevel;
 687
 688                 /// <summary>
 689                 ///   Default target in a switch statement.   Only valid if
 690                 ///   InSwitch is true
 691                 /// </summary>
 692                 public Label DefaultTarget;
 693
 694                 /// <summary>
 695                 ///   If this is non-null, points to the current switch statement
 696                 /// </summary>
 697                 public Switch Switch;
 698
 699                 /// <summary>
 700                 ///   ReturnValue creates on demand the LocalBuilder for the
 701                 ///   return value from the function.  By default this is not
 702                 ///   used.  This is only required when returns are found inside
 703                 ///   Try or Catch statements.
 704                 /// </summary>
 705                 public LocalBuilder TemporaryReturn ()
 706                 {
 707                         if (return_value == null){
 708                                 return_value = ig.DeclareLocal (ReturnType);
 709                                 ReturnLabel = ig.DefineLabel ();
 710                                 HasReturnLabel = true;
 711                         }
 712
 713                         return return_value;
 714                 }
 715
 716                 /// <summary>
 717                 ///   A dynamic This that is shared by all variables in a emitcontext.
 718                 ///   Created on demand.
 719                 /// </summary>
 720                 public Expression my_this;
 721                 public Expression This {
 722                         get {
 723                                 if (my_this == null) {
 724                                         if (CurrentBlock != null)
 725                                                 my_this = new This (CurrentBlock, loc);
 726                                         else
 727                                                 my_this = new This (loc);
 728
 729                                         my_this = my_this.Resolve (this);
 730                                 }
 731
 732                                 return my_this;
 733                         }
 734                 }
 735         }
 736
 737
 738         public abstract class CommonAssemblyModulClass: Attributable {
 739                 protected CommonAssemblyModulClass ():
 740                         base (null)
 741                 {
 742                 }
 743
 744                 public void AddAttribute (Attribute attr)
 745                 {
 746                         if (OptAttributes == null) {
 747                                 OptAttributes = new Attributes (attr);
 748                         } else {
 749                                 OptAttributes.Add (attr);
 750                         }
 751                 }
 752
 753                 public virtual void Emit (TypeContainer tc)
 754                 {
 755                         if (OptAttributes == null)
 756                                 return;
 757                         EmitContext ec = new EmitContext (tc, Location.Null, null, null, 0, false);
 758
 759                         if (OptAttributes != null)
 760                                 OptAttributes.Emit (ec, this);
 761                 }
 762
 763
 764         }
 765
 766         public class AssemblyClass: CommonAssemblyModulClass
 767         {
 768                 public AssemblyBuilder Builder;
 769
 770                 public override AttributeTargets AttributeTargets {
 771                         get {
 772                                 return AttributeTargets.Assembly;
 773                         }
 774                 }
 775
 776                 public override void Emit (TypeContainer tc)
 777                 {
 778                         base.Emit (tc);
 779                 }
 780
 781                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
 782                 {
 783                         Builder.SetCustomAttribute (customBuilder);
 784                 }
 785
 786         }
 787
 788         public class ModuleClass: CommonAssemblyModulClass
 789         {
 790                 public ModuleBuilder Builder;
 791
 792                 public ModuleClass ()
 793                 {
 794                 }
 795
 796                 public override void Emit (TypeContainer tc)
 797                 {
 798                         base.Emit (tc);
 799                 }
 800
 801                 public override AttributeTargets AttributeTargets {
 802                         get {
 803                                 return AttributeTargets.Module;
 804                         }
 805                 }
 806
 807                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
 808                 {
 809                         Builder.SetCustomAttribute (customBuilder);
 810                 }
 811         }
 812 }