remove svn:executable from *.cs
[mono.git] / mcs / gmcs / rootcontext.cs
1 //
2 // rootcontext.cs: keeps track of our tree representation, and assemblies loaded.
3 //
4 // Author: Miguel de Icaza (miguel@ximian.com)
5 //         Ravi Pratap     (ravi@ximian.com)
6 //
7 // Licensed under the terms of the GNU GPL
8 //
9 // (C) 2001 Ximian, Inc (http://www.ximian.com)
10 // (C) 2004 Novell, Inc
11
12 using System;
13 using System.Collections;
14 using System.Reflection;
15 using System.Reflection.Emit;
16 using System.Diagnostics;
17 using System.Xml;
18
19 namespace Mono.CSharp {
20
21         public enum LanguageVersion
22         {
23                 Default = 0,
24                 ISO_1   = 1
25         }
26
27         public class RootContext {
28
29                 //
30                 // Contains the parsed tree
31                 //
32                 static Tree tree;
33
34                 //
35                 // This hashtable contains all of the #definitions across the source code
36                 // it is used by the ConditionalAttribute handler.
37                 //
38                 public static Hashtable AllDefines = new Hashtable ();
39                 
40                 //
41                 // Whether we are being linked against the standard libraries.
42                 // This is only used to tell whether `System.Object' should
43                 // have a parent or not.
44                 //
45                 public static bool StdLib = true;
46
47                 //
48                 // This keeps track of the order in which classes were defined
49                 // so that we can poulate them in that order.
50                 //
51                 // Order is important, because we need to be able to tell by
52                 // examining the parent's list of methods which ones are virtual
53                 // or abstract as well as the parent names (to implement new, 
54                 // override).
55                 //
56                 static ArrayList type_container_resolve_order;
57                 static ArrayList attribute_types;
58
59                 //
60                 // Holds a reference to the Private Implementation Details
61                 // class.
62                 //
63                 static ArrayList helper_classes;
64                 
65                 static TypeBuilder impl_details_class;
66
67                 public static int WarningLevel = 2;
68
69                 public static Target Target = Target.Exe;
70                 public static string TargetExt = ".exe";
71
72                 public static bool VerifyClsCompliance = true;
73
74                 public static LanguageVersion Version = LanguageVersion.Default;
75
76                 //
77                 // We keep strongname related info here because
78                 // it's also used as complier options from CSC 8.x
79                 //
80                 public static string StrongNameKeyFile;
81                 public static string StrongNameKeyContainer;
82                 public static bool StrongNameDelaySign = false;
83
84                 //
85                 // If set, enable XML documentation generation
86                 //
87                 public static Documentation Documentation;
88
89                 //
90                 // Constructor
91                 //
92                 static RootContext ()
93                 {
94                         tree = new Tree ();
95                         type_container_resolve_order = new ArrayList ();
96                 }
97
98                 public static bool NeedsEntryPoint {
99                         get {
100                                 return RootContext.Target == Target.Exe || RootContext.Target == Target.WinExe;
101                         }
102                 }
103
104                 static public Tree Tree {
105                         get {
106                                 return tree;
107                         }
108                 }
109
110                 static public string MainClass;
111                 
112                 public static void RegisterOrder (TypeContainer tc)
113                 {
114                         type_container_resolve_order.Add (tc);
115                 }
116
117                 public static void RegisterAttribute (TypeContainer tc)
118                 {
119                         if (attribute_types == null)
120                                 attribute_types = new ArrayList ();
121                         
122                         attribute_types.Add (tc);
123                 }
124                 
125                 // 
126                 // The default compiler checked state
127                 //
128                 static public bool Checked = false;
129
130                 //
131                 // Whether to allow Unsafe code
132                 //
133                 static public bool Unsafe = false;
134                 
135                 static string MakeFQN (string nsn, string name)
136                 {
137                         if (nsn == "")
138                                 return name;
139                         return String.Concat (nsn, ".", name);
140                 }
141
142                 // <remarks>
143                 //   This function is used to resolve the hierarchy tree.
144                 //   It processes interfaces, structs and classes in that order.
145                 //
146                 //   It creates the TypeBuilder's as it processes the user defined
147                 //   types.  
148                 // </remarks>
149                 static public void ResolveTree ()
150                 {
151                         //
152                         // Process the attribute types separately and before anything else
153                         //
154                         if (attribute_types != null)
155                                 foreach (TypeContainer tc in attribute_types)
156                                         tc.DefineType ();
157                         
158                         //
159                         // Interfaces are processed next, as classes and
160                         // structs might inherit from an object or implement
161                         // a set of interfaces, we need to be able to tell
162                         // them appart by just using the TypeManager.
163                         //
164                         TypeContainer root = Tree.Types;
165
166                         ArrayList ifaces = root.Interfaces;
167                         if (ifaces != null){
168                                 foreach (Interface i in ifaces) 
169                                         i.DefineType ();
170                         }
171
172                         foreach (TypeContainer tc in root.Types)
173                                 tc.DefineType ();
174
175                         if (root.Delegates != null)
176                                 foreach (Delegate d in root.Delegates) 
177                                         d.DefineType ();
178
179                         if (root.Enums != null)
180                                 foreach (Enum e in root.Enums)
181                                         e.DefineType ();
182                 }
183
184                 static void Error_TypeConflict (string name, Location loc)
185                 {
186                         Report.Error (
187                                 520, loc, "`" + name + "' conflicts with a predefined type");
188                 }
189
190                 static void Error_TypeConflict (string name)
191                 {
192                         Report.Error (
193                                 520, "`" + name + "' conflicts with a predefined type");
194                 }
195
196                 //
197                 // Resolves a single class during the corlib bootstrap process
198                 //
199                 static TypeBuilder BootstrapCorlib_ResolveClass (TypeContainer root, string name)
200                 {
201                         object o = root.GetDefinition (name);
202                         if (o == null){
203                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
204                                 return null;
205                         }
206
207                         if (!(o is Class)){
208                                 if (o is DeclSpace){
209                                         DeclSpace d = (DeclSpace) o;
210
211                                         Error_TypeConflict (name, d.Location);
212                                 } else
213                                         Error_TypeConflict (name);
214
215                                 return null;
216                         }
217
218                         return ((DeclSpace) o).DefineType ();
219                 }
220
221                 //
222                 // Resolves a struct during the corlib bootstrap process
223                 //
224                 static void BootstrapCorlib_ResolveStruct (TypeContainer root, string name)
225                 {
226                         object o = root.GetDefinition (name);
227                         if (o == null){
228                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
229                                 return;
230                         }
231
232                         if (!(o is Struct)){
233                                 if (o is DeclSpace){
234                                         DeclSpace d = (DeclSpace) o;
235
236                                         Error_TypeConflict (name, d.Location);
237                                 } else
238                                         Error_TypeConflict (name);
239
240                                 return;
241                         }
242
243                         ((DeclSpace) o).DefineType ();
244                 }
245
246                 //
247                 // Resolves a struct during the corlib bootstrap process
248                 //
249                 static void BootstrapCorlib_ResolveInterface (TypeContainer root, string name)
250                 {
251                         object o = root.GetDefinition (name);
252                         if (o == null){
253                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
254                                 return;
255                         }
256
257                         if (!(o is Interface)){
258                                 if (o is DeclSpace){
259                                         DeclSpace d = (DeclSpace) o;
260
261                                         Error_TypeConflict (name, d.Location);
262                                 } else
263                                         Error_TypeConflict (name);
264
265                                 return;
266                         }
267
268                         ((DeclSpace) o).DefineType ();
269                 }
270
271                 //
272                 // Resolves a delegate during the corlib bootstrap process
273                 //
274                 static void BootstrapCorlib_ResolveDelegate (TypeContainer root, string name)
275                 {
276                         object o = root.GetDefinition (name);
277                         if (o == null){
278                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
279                                 Environment.Exit (1);
280                         }
281
282                         if (!(o is Delegate)){
283                                 Error_TypeConflict (name);
284                                 return;
285                         }
286
287                         ((DeclSpace) o).DefineType ();
288                 }
289                 
290
291                 /// <summary>
292                 ///    Resolves the core types in the compiler when compiling with --nostdlib
293                 /// </summary>
294                 static public void ResolveCore ()
295                 {
296                         TypeContainer root = Tree.Types;
297
298                         TypeManager.object_type = BootstrapCorlib_ResolveClass (root, "System.Object");
299                         TypeManager.value_type = BootstrapCorlib_ResolveClass (root, "System.ValueType");
300                         TypeManager.attribute_type = BootstrapCorlib_ResolveClass (root, "System.Attribute");
301                         
302                         string [] interfaces_first_stage = {
303                                 "System.IComparable", "System.ICloneable",
304                                 "System.IConvertible",
305                                 
306                                 "System.Collections.IEnumerable",
307                                 "System.Collections.ICollection",
308                                 "System.Collections.IEnumerator",
309                                 "System.Collections.IList", 
310                                 "System.IAsyncResult",
311                                 "System.IDisposable",
312                                 
313                                 "System.Runtime.Serialization.ISerializable",
314                                 "System.Runtime.InteropServices._Exception",
315
316                                 "System.Reflection.IReflect",
317                                 "System.Reflection.ICustomAttributeProvider",
318
319                                 //
320                                 // Generic types
321                                 //
322                                 "System.Collections.Generic.IEnumerator`1",
323                                 "System.Collections.Generic.IEnumerable`1"
324                         };
325
326                         foreach (string iname in interfaces_first_stage)
327                                 BootstrapCorlib_ResolveInterface (root, iname);
328
329                         //
330                         // These are the base value types
331                         //
332                         string [] structs_first_stage = {
333                                 "System.Byte",    "System.SByte",
334                                 "System.Int16",   "System.UInt16",
335                                 "System.Int32",   "System.UInt32",
336                                 "System.Int64",   "System.UInt64",
337                         };
338
339                         foreach (string cname in structs_first_stage)
340                                 BootstrapCorlib_ResolveStruct (root, cname);
341
342                         //
343                         // Now, we can load the enumerations, after this point,
344                         // we can use enums.
345                         //
346                         TypeManager.InitEnumUnderlyingTypes ();
347
348                         string [] structs_second_stage = {
349                                 "System.Single",  "System.Double",
350                                 "System.Char",    "System.Boolean",
351                                 "System.Decimal", "System.Void",
352                                 "System.RuntimeFieldHandle",
353                                 "System.RuntimeArgumentHandle",
354                                 "System.RuntimeTypeHandle",
355                                 "System.IntPtr",
356                                 "System.TypedReference",
357                                 "System.ArgIterator"
358                         };
359                         
360                         foreach (string cname in structs_second_stage)
361                                 BootstrapCorlib_ResolveStruct (root, cname);
362                         
363                         //
364                         // These are classes that depends on the core interfaces
365                         //
366                         string [] classes_second_stage = {
367                                 "System.Reflection.MemberInfo",
368                                 "System.Type",
369                                 "System.Exception",
370                                 "System.Activator",
371
372                                 //
373                                 // These are not really important in the order, but they
374                                 // are used by the compiler later on (typemanager/CoreLookupType-d)
375                                 //
376                                 "System.Runtime.CompilerServices.RuntimeHelpers",
377                                 "System.Reflection.DefaultMemberAttribute",
378                                 "System.Threading.Monitor",
379                                 
380                                 "System.AttributeUsageAttribute",
381                                 "System.Runtime.InteropServices.DllImportAttribute",
382                                 "System.Runtime.CompilerServices.MethodImplAttribute",
383                                 "System.Runtime.InteropServices.MarshalAsAttribute",
384                                 "System.Runtime.CompilerServices.NewConstraintAttribute",
385                                 "System.Diagnostics.ConditionalAttribute",
386                                 "System.ObsoleteAttribute",
387                                 "System.ParamArrayAttribute",
388                                 "System.CLSCompliantAttribute",
389                                 "System.Security.UnverifiableCodeAttribute",
390                                 "System.Security.Permissions.SecurityAttribute",
391                                 "System.Runtime.CompilerServices.IndexerNameAttribute",
392                                 "System.Runtime.CompilerServices.DecimalConstantAttribute",
393                                 "System.Runtime.InteropServices.InAttribute",
394                                 "System.Runtime.InteropServices.StructLayoutAttribute",
395                                 "System.Runtime.InteropServices.FieldOffsetAttribute",
396                                 "System.InvalidOperationException",
397                                 "System.NotSupportedException",
398                                 "System.MarshalByRefObject",
399                                 "System.Security.CodeAccessPermission"
400                         };
401
402                         // We must store them here before calling BootstrapCorlib_ResolveDelegate.
403                         TypeManager.string_type = BootstrapCorlib_ResolveClass (root, "System.String");
404                         TypeManager.enum_type = BootstrapCorlib_ResolveClass (root, "System.Enum");
405                         TypeManager.array_type = BootstrapCorlib_ResolveClass (root, "System.Array");
406                         TypeManager.multicast_delegate_type = BootstrapCorlib_ResolveClass (root, "System.MulticastDelegate");
407                         TypeManager.delegate_type = BootstrapCorlib_ResolveClass (root, "System.Delegate");
408                         
409                         foreach (string cname in classes_second_stage)
410                                 BootstrapCorlib_ResolveClass (root, cname);
411
412                         BootstrapCorlib_ResolveDelegate (root, "System.AsyncCallback");
413                 }
414                         
415                 // <summary>
416                 //   Closes all open types
417                 // </summary>
418                 //
419                 // <remarks>
420                 //   We usually use TypeBuilder types.  When we are done
421                 //   creating the type (which will happen after we have added
422                 //   methods, fields, etc) we need to "Define" them before we
423                 //   can save the Assembly
424                 // </remarks>
425                 static public void CloseTypes ()
426                 {
427                         TypeContainer root = Tree.Types;
428                         
429                         if (root.Enums != null)
430                                 foreach (Enum en in root.Enums)
431                                         en.CloseType ();
432
433                         if (attribute_types != null)
434                                 foreach (TypeContainer tc in attribute_types)
435                                         tc.CloseType ();
436                         
437                         //
438                         // We do this in two passes, first we close the structs,
439                         // then the classes, because it seems the code needs it this
440                         // way.  If this is really what is going on, we should probably
441                         // make sure that we define the structs in order as well.
442                         //
443                         foreach (TypeContainer tc in type_container_resolve_order){
444                                 if (tc.Kind == Kind.Struct && tc.Parent == tree.Types){
445                                         tc.CloseType ();
446                                 }
447                         }
448
449                         foreach (TypeContainer tc in type_container_resolve_order){
450                                 if (!(tc.Kind == Kind.Struct && tc.Parent == tree.Types))
451                                         tc.CloseType ();                                        
452                         }
453                         
454                         if (root.Delegates != null)
455                                 foreach (Delegate d in root.Delegates)
456                                         d.CloseType ();
457
458
459                         //
460                         // If we have a <PrivateImplementationDetails> class, close it
461                         //
462                         if (helper_classes != null){
463                                 foreach (TypeBuilder type_builder in helper_classes)
464                                         type_builder.CreateType ();
465                         }
466                         
467                         attribute_types = null;
468                         type_container_resolve_order = null;
469                         helper_classes = null;
470                         //tree = null;
471                         TypeManager.CleanUp ();
472                 }
473
474                 /// <summary>
475                 ///   Used to register classes that need to be closed after all the
476                 ///   user defined classes
477                 /// </summary>
478                 public static void RegisterHelperClass (TypeBuilder helper_class)
479                 {
480                         if (helper_classes == null)
481                                 helper_classes = new ArrayList ();
482                         helper_classes.Add (helper_class);
483                 }
484                 
485                 //
486                 // This idea is from Felix Arrese-Igor
487                 //
488                 // Returns : the implicit parent of a composite namespace string
489                 //   eg. Implicit parent of A.B is A
490                 //
491                 static public string ImplicitParent (string ns)
492                 {
493                         int i = ns.LastIndexOf ('.');
494                         if (i < 0)
495                                 return null;
496                         
497                         return ns.Substring (0, i);
498                 }
499
500                 static Type NamespaceLookup (DeclSpace ds, string name, int num_type_args, Location loc)
501                 {
502                         IAlias result = ds.NamespaceEntry.LookupNamespaceOrType (ds, name, loc);
503                         if (result == null)
504                                 return null;
505
506                         if (!result.IsType)
507                                 return null;
508
509                         TypeExpr texpr = result.ResolveAsType (ds.EmitContext);
510                         if (texpr == null)
511                                 return null;
512
513                         return texpr.Type;
514                 }
515                 
516                 static public Type LookupType (DeclSpace ds, string name, bool silent, Location loc)
517                 {
518                         return LookupType (ds, name, silent, 0, loc);
519                 }
520
521                 //
522                 // Public function used to locate types, this can only
523                 // be used after the ResolveTree function has been invoked.
524                 //
525                 // Returns: Type or null if they type can not be found.
526                 //
527                 // Come to think of it, this should be a DeclSpace
528                 //
529                 static public Type LookupType (DeclSpace ds, string name, bool silent,
530                                                int num_type_params, Location loc)
531                 {
532                         Type t;
533
534                         if (ds.Cache.Contains (name)){
535                                 t = (Type) ds.Cache [name];
536                                 if (t != null)
537                                         return t;
538                         } else {
539                                 //
540                                 // For the case the type we are looking for is nested within this one
541                                 // or is in any base class
542                                 //
543                                 DeclSpace containing_ds = ds;
544                                 while (containing_ds != null){
545                                         Type current_type = containing_ds.TypeBuilder;
546                                         
547                                         while (current_type != null) {
548                                                 //
549                                                 // nested class
550                                                 //
551                                                 Type type = TypeManager.LookupType (current_type.FullName + "." + name);
552                                                 if (type != null){
553                                                         t = ds.ResolveNestedType (type, loc);
554                                                         ds.Cache [name] = t;
555                                                         return t;
556                                                 }
557                                                 
558                                                 current_type = current_type.BaseType;
559                                         }
560                                         
561                                         containing_ds = containing_ds.Parent;
562                                 }
563                                 
564                                 t = NamespaceLookup (ds, name, num_type_params, loc);
565                                 if (!silent || t != null){
566                                         ds.Cache [name] = t;
567                                         return t;
568                                 }
569                         }
570
571                         if (!silent)
572                                 Report.Error (246, loc, "Cannot find type `"+name+"'");
573                         
574                         return null;
575                 }
576
577                 // <summary>
578                 //   This is the silent version of LookupType, you can use this
579                 //   to `probe' for a type
580                 // </summary>
581                 static public Type LookupType (TypeContainer tc, string name, Location loc)
582                 {
583                         return LookupType (tc, name, true, loc);
584                 }
585
586                 static void Report1530 (Location loc)
587                 {
588                         Report.Error (1530, loc, "Keyword new not allowed for namespace elements");
589                 }
590                 
591                 static public void PopulateCoreType (TypeContainer root, string name)
592                 {
593                         DeclSpace ds = (DeclSpace) root.GetDefinition (name);
594
595                         ds.DefineMembers (root);
596                         ds.Define ();
597                 }
598                 
599                 static public void BootCorlib_PopulateCoreTypes ()
600                 {
601                         TypeContainer root = tree.Types;
602
603                         PopulateCoreType (root, "System.Object");
604                         PopulateCoreType (root, "System.ValueType");
605                         PopulateCoreType (root, "System.Attribute");
606                 }
607                 
608                 // <summary>
609                 //   Populates the structs and classes with fields and methods
610                 // </summary>
611                 //
612                 // This is invoked after all interfaces, structs and classes
613                 // have been defined through `ResolveTree' 
614                 static public void PopulateTypes ()
615                 {
616                         TypeContainer root = Tree.Types;
617
618                         if (attribute_types != null)
619                                 foreach (TypeContainer tc in attribute_types)
620                                         tc.DefineMembers (root);
621
622                         if (type_container_resolve_order != null){
623                                 if (RootContext.StdLib){
624                                         foreach (TypeContainer tc in type_container_resolve_order)
625                                                 tc.DefineMembers (root);
626                                 } else {
627                                         foreach (TypeContainer tc in type_container_resolve_order) {
628                                                 // When compiling corlib, these types have already been
629                                                 // populated from BootCorlib_PopulateCoreTypes ().
630                                                 if (((tc.Name == "System.Object") ||
631                                                      (tc.Name == "System.Attribute") ||
632                                                      (tc.Name == "System.ValueType")))
633                                                 continue;
634
635                                                 tc.DefineMembers (root);
636                                         }
637                                 } 
638                         }
639
640                         ArrayList delegates = root.Delegates;
641                         if (delegates != null){
642                                 foreach (Delegate d in delegates)
643                                         if ((d.ModFlags & Modifiers.NEW) == 0)
644                                                 d.DefineMembers (root);
645                                         else
646                                                 Report1530 (d.Location);
647                         }
648
649                         ArrayList enums = root.Enums;
650                         if (enums != null){
651                                 foreach (Enum en in enums)
652                                         if ((en.ModFlags & Modifiers.NEW) == 0)
653                                                 en.DefineMembers (root);
654                                         else
655                                                 Report1530 (en.Location);
656                         }
657
658                         //
659                         // Check for cycles in the struct layout
660                         //
661                         if (type_container_resolve_order != null){
662                                 Hashtable seen = new Hashtable ();
663                                 foreach (TypeContainer tc in type_container_resolve_order)
664                                         TypeManager.CheckStructCycles (tc, seen);
665                         }
666                 }
667
668                 //
669                 // A generic hook delegate
670                 //
671                 public delegate void Hook ();
672
673                 //
674                 // A hook invoked when the code has been generated.
675                 //
676                 public static event Hook EmitCodeHook;
677
678                 //
679                 // DefineTypes is used to fill in the members of each type.
680                 //
681                 static public void DefineTypes ()
682                 {
683                         TypeContainer root = Tree.Types;
684
685                         if (attribute_types != null)
686                                 foreach (TypeContainer tc in attribute_types)
687                                         tc.Define ();
688
689                         if (type_container_resolve_order != null){
690                                 foreach (TypeContainer tc in type_container_resolve_order) {
691                                         // When compiling corlib, these types have already been
692                                         // populated from BootCorlib_PopulateCoreTypes ().
693                                         if (!RootContext.StdLib &&
694                                             ((tc.Name == "System.Object") ||
695                                              (tc.Name == "System.Attribute") ||
696                                              (tc.Name == "System.ValueType")))
697                                                 continue;
698
699                                         if ((tc.ModFlags & Modifiers.NEW) == 0)
700                                                 tc.Define ();
701                                 }
702                         }
703
704                         ArrayList delegates = root.Delegates;
705                         if (delegates != null){
706                                 foreach (Delegate d in delegates)
707                                         if ((d.ModFlags & Modifiers.NEW) == 0)
708                                                 d.Define ();
709                         }
710
711                         ArrayList enums = root.Enums;
712                         if (enums != null){
713                                 foreach (Enum en in enums)
714                                         if ((en.ModFlags & Modifiers.NEW) == 0)
715                                                 en.Define ();
716                         }
717                 }
718
719                 static public void EmitCode ()
720                 {
721                         if (attribute_types != null)
722                                 foreach (TypeContainer tc in attribute_types)
723                                         tc.EmitType ();
724
725                         CodeGen.Assembly.Emit (Tree.Types);
726                         CodeGen.Module.Emit (Tree.Types);
727                         
728                         if (Tree.Types.Enums != null) {
729                                 foreach (Enum e in Tree.Types.Enums)
730                                         e.Emit ();
731                         }
732
733                         if (type_container_resolve_order != null) {
734                                 foreach (TypeContainer tc in type_container_resolve_order)
735                                         tc.EmitType ();
736                         }
737                         
738                         if (Tree.Types.Delegates != null) {
739                                 foreach (Delegate d in Tree.Types.Delegates)
740                                         d.Emit ();
741                         }                       
742                         //
743                         // Run any hooks after all the types have been defined.
744                         // This is used to create nested auxiliary classes for example
745                         //
746
747                         if (EmitCodeHook != null)
748                                 EmitCodeHook ();
749                 }
750                 
751                 //
752                 // Public Field, used to track which method is the public entry
753                 // point.
754                 //
755                 static public MethodInfo EntryPoint;
756
757                 //
758                 // Track the location of the entry point.
759                 //
760                 static public Location EntryPointLocation;
761
762                 //
763                 // These are used to generate unique names on the structs and fields.
764                 //
765                 static int field_count;
766                 
767                 //
768                 // Makes an initialized struct, returns the field builder that
769                 // references the data.  Thanks go to Sergey Chaban for researching
770                 // how to do this.  And coming up with a shorter mechanism than I
771                 // was able to figure out.
772                 //
773                 // This works but makes an implicit public struct $ArrayType$SIZE and
774                 // makes the fields point to it.  We could get more control if we did
775                 // use instead:
776                 //
777                 // 1. DefineNestedType on the impl_details_class with our struct.
778                 //
779                 // 2. Define the field on the impl_details_class
780                 //
781                 static public FieldBuilder MakeStaticData (byte [] data)
782                 {
783                         FieldBuilder fb;
784                         
785                         if (impl_details_class == null){
786                                 impl_details_class = CodeGen.Module.Builder.DefineType (
787                                         "<PrivateImplementationDetails>",
788                                         TypeAttributes.NotPublic,
789                                         TypeManager.object_type);
790                                 
791                                 RegisterHelperClass (impl_details_class);
792                         }
793
794                         fb = impl_details_class.DefineInitializedData (
795                                 "$$field-" + (field_count++), data,
796                                 FieldAttributes.Static | FieldAttributes.Assembly);
797                         
798                         return fb;
799                 }
800         }
801 }
802               
803