**** Merged r36189 from MCS ****
[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
11 using System;
12 using System.Collections;
13 using System.Reflection;
14 using System.Reflection.Emit;
15 using System.Diagnostics;
16
17 namespace Mono.CSharp {
18
19         public enum LanguageVersion
20         {
21                 Default = 0,
22                 ISO_1   = 1
23         }
24
25         public class RootContext {
26
27                 //
28                 // Contains the parsed tree
29                 //
30                 static Tree tree;
31
32                 //
33                 // This hashtable contains all of the #definitions across the source code
34                 // it is used by the ConditionalAttribute handler.
35                 //
36                 public static Hashtable AllDefines = new Hashtable ();
37                 
38                 //
39                 // Whether we are being linked against the standard libraries.
40                 // This is only used to tell whether `System.Object' should
41                 // have a parent or not.
42                 //
43                 public static bool StdLib = true;
44
45                 //
46                 // This keeps track of the order in which classes were defined
47                 // so that we can poulate them in that order.
48                 //
49                 // Order is important, because we need to be able to tell by
50                 // examining the parent's list of methods which ones are virtual
51                 // or abstract as well as the parent names (to implement new, 
52                 // override).
53                 //
54                 static ArrayList type_container_resolve_order;
55                 static ArrayList attribute_types;
56
57                 //
58                 // Holds a reference to the Private Implementation Details
59                 // class.
60                 //
61                 static ArrayList helper_classes;
62                 
63                 static TypeBuilder impl_details_class;
64
65                 public static int WarningLevel = 2;
66
67                 public static Target Target = Target.Exe;
68                 public static string TargetExt = ".exe";
69
70                 public static bool VerifyClsCompliance = true;
71
72                 public static LanguageVersion Version = LanguageVersion.Default;
73
74                 //
75                 // We keep strongname related info here because
76                 // it's also used as complier options from CSC 8.x
77                 //
78                 public static string StrongNameKeyFile;
79                 public static string StrongNameKeyContainer;
80                 public static bool StrongNameDelaySign = false;
81
82                 //
83                 // Constructor
84                 //
85                 static RootContext ()
86                 {
87                         tree = new Tree ();
88                         type_container_resolve_order = new ArrayList ();
89                 }
90
91                 public static bool NeedsEntryPoint {
92                         get {
93                                 return RootContext.Target == Target.Exe || RootContext.Target == Target.WinExe;
94                         }
95                 }
96
97                 static public Tree Tree {
98                         get {
99                                 return tree;
100                         }
101                 }
102
103                 static public string MainClass;
104                 
105                 public static void RegisterOrder (TypeContainer tc)
106                 {
107                         type_container_resolve_order.Add (tc);
108                 }
109
110                 public static void RegisterAttribute (TypeContainer tc)
111                 {
112                         if (attribute_types == null)
113                                 attribute_types = new ArrayList ();
114                         
115                         attribute_types.Add (tc);
116                 }
117                 
118                 // 
119                 // The default compiler checked state
120                 //
121                 static public bool Checked = false;
122
123                 //
124                 // Whether to allow Unsafe code
125                 //
126                 static public bool Unsafe = false;
127                 
128                 static string MakeFQN (string nsn, string name)
129                 {
130                         if (nsn == "")
131                                 return name;
132                         return String.Concat (nsn, ".", name);
133                 }
134
135                 // <remarks>
136                 //   This function is used to resolve the hierarchy tree.
137                 //   It processes interfaces, structs and classes in that order.
138                 //
139                 //   It creates the TypeBuilder's as it processes the user defined
140                 //   types.  
141                 // </remarks>
142                 static public void ResolveTree ()
143                 {
144                         //
145                         // Process the attribute types separately and before anything else
146                         //
147                         if (attribute_types != null)
148                                 foreach (TypeContainer tc in attribute_types)
149                                         tc.DefineType ();
150                         
151                         //
152                         // Interfaces are processed next, as classes and
153                         // structs might inherit from an object or implement
154                         // a set of interfaces, we need to be able to tell
155                         // them appart by just using the TypeManager.
156                         //
157                         TypeContainer root = Tree.Types;
158
159                         ArrayList ifaces = root.Interfaces;
160                         if (ifaces != null){
161                                 foreach (Interface i in ifaces) 
162                                         i.DefineType ();
163                         }
164
165                         foreach (TypeContainer tc in root.Types)
166                                 tc.DefineType ();
167
168                         if (root.Delegates != null)
169                                 foreach (Delegate d in root.Delegates) 
170                                         d.DefineType ();
171
172                         if (root.Enums != null)
173                                 foreach (Enum e in root.Enums)
174                                         e.DefineType ();
175                 }
176
177                 static void Error_TypeConflict (string name, Location loc)
178                 {
179                         Report.Error (
180                                 520, loc, "`" + name + "' conflicts with a predefined type");
181                 }
182
183                 static void Error_TypeConflict (string name)
184                 {
185                         Report.Error (
186                                 520, "`" + name + "' conflicts with a predefined type");
187                 }
188
189                 //
190                 // Resolves a single class during the corlib bootstrap process
191                 //
192                 static TypeBuilder BootstrapCorlib_ResolveClass (TypeContainer root, string name)
193                 {
194                         object o = root.GetDefinition (name);
195                         if (o == null){
196                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
197                                 return null;
198                         }
199
200                         if (!(o is Class)){
201                                 if (o is DeclSpace){
202                                         DeclSpace d = (DeclSpace) o;
203
204                                         Error_TypeConflict (name, d.Location);
205                                 } else
206                                         Error_TypeConflict (name);
207
208                                 return null;
209                         }
210
211                         return ((DeclSpace) o).DefineType ();
212                 }
213
214                 //
215                 // Resolves a struct during the corlib bootstrap process
216                 //
217                 static void BootstrapCorlib_ResolveStruct (TypeContainer root, string name)
218                 {
219                         object o = root.GetDefinition (name);
220                         if (o == null){
221                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
222                                 return;
223                         }
224
225                         if (!(o is Struct)){
226                                 if (o is DeclSpace){
227                                         DeclSpace d = (DeclSpace) o;
228
229                                         Error_TypeConflict (name, d.Location);
230                                 } else
231                                         Error_TypeConflict (name);
232
233                                 return;
234                         }
235
236                         ((DeclSpace) o).DefineType ();
237                 }
238
239                 //
240                 // Resolves a struct during the corlib bootstrap process
241                 //
242                 static void BootstrapCorlib_ResolveInterface (TypeContainer root, string name)
243                 {
244                         object o = root.GetDefinition (name);
245                         if (o == null){
246                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
247                                 return;
248                         }
249
250                         if (!(o is Interface)){
251                                 if (o is DeclSpace){
252                                         DeclSpace d = (DeclSpace) o;
253
254                                         Error_TypeConflict (name, d.Location);
255                                 } else
256                                         Error_TypeConflict (name);
257
258                                 return;
259                         }
260
261                         ((DeclSpace) o).DefineType ();
262                 }
263
264                 //
265                 // Resolves a delegate during the corlib bootstrap process
266                 //
267                 static void BootstrapCorlib_ResolveDelegate (TypeContainer root, string name)
268                 {
269                         object o = root.GetDefinition (name);
270                         if (o == null){
271                                 Report.Error (518, "The predefined type `" + name + "' is not defined");
272                                 Environment.Exit (1);
273                         }
274
275                         if (!(o is Delegate)){
276                                 Error_TypeConflict (name);
277                                 return;
278                         }
279
280                         ((DeclSpace) o).DefineType ();
281                 }
282                 
283
284                 /// <summary>
285                 ///    Resolves the core types in the compiler when compiling with --nostdlib
286                 /// </summary>
287                 static public void ResolveCore ()
288                 {
289                         TypeContainer root = Tree.Types;
290
291                         TypeManager.object_type = BootstrapCorlib_ResolveClass (root, "System.Object");
292                         TypeManager.value_type = BootstrapCorlib_ResolveClass (root, "System.ValueType");
293                         TypeManager.attribute_type = BootstrapCorlib_ResolveClass (root, "System.Attribute");
294                         
295                         string [] interfaces_first_stage = {
296                                 "System.IComparable", "System.ICloneable",
297                                 "System.IConvertible",
298                                 
299                                 "System.Collections.IEnumerable",
300                                 "System.Collections.ICollection",
301                                 "System.Collections.IEnumerator",
302                                 "System.Collections.IList", 
303                                 "System.IAsyncResult",
304                                 "System.IDisposable",
305                                 
306                                 "System.Runtime.Serialization.ISerializable",
307
308                                 "System.Reflection.IReflect",
309                                 "System.Reflection.ICustomAttributeProvider",
310
311                                 //
312                                 // Generic types
313                                 //
314                                 "System.Collections.Generic.IEnumerator`1",
315                                 "System.Collections.Generic.IEnumerable`1"
316                         };
317
318                         foreach (string iname in interfaces_first_stage)
319                                 BootstrapCorlib_ResolveInterface (root, iname);
320
321                         //
322                         // These are the base value types
323                         //
324                         string [] structs_first_stage = {
325                                 "System.Byte",    "System.SByte",
326                                 "System.Int16",   "System.UInt16",
327                                 "System.Int32",   "System.UInt32",
328                                 "System.Int64",   "System.UInt64",
329                         };
330
331                         foreach (string cname in structs_first_stage)
332                                 BootstrapCorlib_ResolveStruct (root, cname);
333
334                         //
335                         // Now, we can load the enumerations, after this point,
336                         // we can use enums.
337                         //
338                         TypeManager.InitEnumUnderlyingTypes ();
339
340                         string [] structs_second_stage = {
341                                 "System.Single",  "System.Double",
342                                 "System.Char",    "System.Boolean",
343                                 "System.Decimal", "System.Void",
344                                 "System.RuntimeFieldHandle",
345                                 "System.RuntimeArgumentHandle",
346                                 "System.RuntimeTypeHandle",
347                                 "System.IntPtr",
348                                 "System.TypedReference",
349                                 "System.ArgIterator"
350                         };
351                         
352                         foreach (string cname in structs_second_stage)
353                                 BootstrapCorlib_ResolveStruct (root, cname);
354                         
355                         //
356                         // These are classes that depends on the core interfaces
357                         //
358                         string [] classes_second_stage = {
359                                 "System.Reflection.MemberInfo",
360                                 "System.Type",
361                                 "System.Exception",
362                                 "System.Activator",
363
364                                 //
365                                 // These are not really important in the order, but they
366                                 // are used by the compiler later on (typemanager/CoreLookupType-d)
367                                 //
368                                 "System.Runtime.CompilerServices.RuntimeHelpers",
369                                 "System.Reflection.DefaultMemberAttribute",
370                                 "System.Threading.Monitor",
371                                 
372                                 "System.AttributeUsageAttribute",
373                                 "System.Runtime.InteropServices.DllImportAttribute",
374                                 "System.Runtime.CompilerServices.MethodImplAttribute",
375                                 "System.Runtime.InteropServices.MarshalAsAttribute",
376                                 "System.Runtime.CompilerServices.NewConstraintAttribute",
377                                 "System.Diagnostics.ConditionalAttribute",
378                                 "System.ObsoleteAttribute",
379                                 "System.ParamArrayAttribute",
380                                 "System.CLSCompliantAttribute",
381                                 "System.Security.UnverifiableCodeAttribute",
382                                 "System.Security.Permissions.SecurityAttribute",
383                                 "System.Runtime.CompilerServices.IndexerNameAttribute",
384                                 "System.Runtime.InteropServices.InAttribute",
385                                 "System.Runtime.InteropServices.StructLayoutAttribute",
386                                 "System.Runtime.InteropServices.FieldOffsetAttribute",
387                                 "System.InvalidOperationException",
388                                 "System.NotSupportedException",
389                                 "System.MarshalByRefObject",
390                                 "System.Security.CodeAccessPermission"
391                         };
392
393                         // We must store them here before calling BootstrapCorlib_ResolveDelegate.
394                         TypeManager.string_type = BootstrapCorlib_ResolveClass (root, "System.String");
395                         TypeManager.enum_type = BootstrapCorlib_ResolveClass (root, "System.Enum");
396                         TypeManager.array_type = BootstrapCorlib_ResolveClass (root, "System.Array");
397                         TypeManager.multicast_delegate_type = BootstrapCorlib_ResolveClass (root, "System.MulticastDelegate");
398                         TypeManager.delegate_type = BootstrapCorlib_ResolveClass (root, "System.Delegate");
399                         
400                         foreach (string cname in classes_second_stage)
401                                 BootstrapCorlib_ResolveClass (root, cname);
402
403                         BootstrapCorlib_ResolveDelegate (root, "System.AsyncCallback");
404                 }
405                         
406                 // <summary>
407                 //   Closes all open types
408                 // </summary>
409                 //
410                 // <remarks>
411                 //   We usually use TypeBuilder types.  When we are done
412                 //   creating the type (which will happen after we have added
413                 //   methods, fields, etc) we need to "Define" them before we
414                 //   can save the Assembly
415                 // </remarks>
416                 static public void CloseTypes ()
417                 {
418                         TypeContainer root = Tree.Types;
419                         
420                         if (root.Enums != null)
421                                 foreach (Enum en in root.Enums)
422                                         en.CloseType ();
423
424                         if (attribute_types != null)
425                                 foreach (TypeContainer tc in attribute_types)
426                                         tc.CloseType ();
427                         
428                         //
429                         // We do this in two passes, first we close the structs,
430                         // then the classes, because it seems the code needs it this
431                         // way.  If this is really what is going on, we should probably
432                         // make sure that we define the structs in order as well.
433                         //
434                         foreach (TypeContainer tc in type_container_resolve_order){
435                                 if (tc.Kind == Kind.Struct && tc.Parent == tree.Types){
436                                         tc.CloseType ();
437                                 }
438                         }
439
440                         foreach (TypeContainer tc in type_container_resolve_order){
441                                 if (!(tc.Kind == Kind.Struct && tc.Parent == tree.Types))
442                                         tc.CloseType ();                                        
443                         }
444                         
445                         if (root.Delegates != null)
446                                 foreach (Delegate d in root.Delegates)
447                                         d.CloseType ();
448
449
450                         //
451                         // If we have a <PrivateImplementationDetails> class, close it
452                         //
453                         if (helper_classes != null){
454                                 foreach (TypeBuilder type_builder in helper_classes)
455                                         type_builder.CreateType ();
456                         }
457                         
458                         attribute_types = null;
459                         type_container_resolve_order = null;
460                         helper_classes = null;
461                         //tree = null;
462                         TypeManager.CleanUp ();
463                 }
464
465                 /// <summary>
466                 ///   Used to register classes that need to be closed after all the
467                 ///   user defined classes
468                 /// </summary>
469                 public static void RegisterHelperClass (TypeBuilder helper_class)
470                 {
471                         if (helper_classes == null)
472                                 helper_classes = new ArrayList ();
473                         helper_classes.Add (helper_class);
474                 }
475                 
476                 //
477                 // This idea is from Felix Arrese-Igor
478                 //
479                 // Returns : the implicit parent of a composite namespace string
480                 //   eg. Implicit parent of A.B is A
481                 //
482                 static public string ImplicitParent (string ns)
483                 {
484                         int i = ns.LastIndexOf ('.');
485                         if (i < 0)
486                                 return null;
487                         
488                         return ns.Substring (0, i);
489                 }
490
491                 static Type NamespaceLookup (DeclSpace ds, string name, int num_type_args, Location loc)
492                 {
493                         //
494                         // Try in the current namespace and all its implicit parents
495                         //
496                         for (NamespaceEntry ns = ds.NamespaceEntry; ns != null; ns = ns.ImplicitParent) {
497                                 IAlias result = ns.Lookup (ds, name, num_type_args, false, loc);
498
499                                 if (result == null)
500                                         continue;
501
502                                 if (!result.IsType)
503                                         return null;
504
505                                 TypeExpr texpr = result.ResolveAsType (ds.EmitContext);
506                                 if (texpr == null)
507                                         return null;
508
509                                 return texpr.Type;
510                         }
511
512                         return null;
513                 }
514                 
515                 static public Type LookupType (DeclSpace ds, string name, bool silent, Location loc)
516                 {
517                         return LookupType (ds, name, silent, 0, loc);
518                 }
519
520                 //
521                 // Public function used to locate types, this can only
522                 // be used after the ResolveTree function has been invoked.
523                 //
524                 // Returns: Type or null if they type can not be found.
525                 //
526                 // Come to think of it, this should be a DeclSpace
527                 //
528                 static public Type LookupType (DeclSpace ds, string name, bool silent,
529                                                int num_type_params, Location loc)
530                 {
531                         Type t;
532
533                         if (ds.Cache.Contains (name)){
534                                 t = (Type) ds.Cache [name];
535                                 if (t != null)
536                                         return t;
537                         } else {
538                                 //
539                                 // For the case the type we are looking for is nested within this one
540                                 // or is in any base class
541                                 //
542                                 DeclSpace containing_ds = ds;
543                                 while (containing_ds != null){
544                                         Type current_type = containing_ds.TypeBuilder;
545                                         
546                                         while (current_type != null) {
547                                                 //
548                                                 // nested class
549                                                 //
550                                                 Type type = TypeManager.LookupType (current_type.FullName + "." + name);
551                                                 if (type != null){
552                                                         t = ds.ResolveNestedType (type, loc);
553                                                         ds.Cache [name] = t;
554                                                         return t;
555                                                 }
556                                                 
557                                                 current_type = current_type.BaseType;
558                                         }
559                                         
560                                         containing_ds = containing_ds.Parent;
561                                 }
562                                 
563                                 t = NamespaceLookup (ds, name, num_type_params, loc);
564                                 if (t != null){
565                                         ds.Cache [name] = t;
566                                         return t;
567                                 }
568                         }
569
570                         if (!silent)
571                                 Report.Error (246, loc, "Cannot find type `"+name+"'");
572                         
573                         return null;
574                 }
575
576                 // <summary>
577                 //   This is the silent version of LookupType, you can use this
578                 //   to `probe' for a type
579                 // </summary>
580                 static public Type LookupType (TypeContainer tc, string name, Location loc)
581                 {
582                         return LookupType (tc, name, true, loc);
583                 }
584
585                 static void Report1530 (Location loc)
586                 {
587                         Report.Error (1530, loc, "Keyword new not allowed for namespace elements");
588                 }
589                 
590                 static public void PopulateCoreType (TypeContainer root, string name)
591                 {
592                         DeclSpace ds = (DeclSpace) root.GetDefinition (name);
593
594                         ds.DefineMembers (root);
595                         ds.Define ();
596                 }
597                 
598                 static public void BootCorlib_PopulateCoreTypes ()
599                 {
600                         TypeContainer root = tree.Types;
601
602                         PopulateCoreType (root, "System.Object");
603                         PopulateCoreType (root, "System.ValueType");
604                         PopulateCoreType (root, "System.Attribute");
605                 }
606                 
607                 // <summary>
608                 //   Populates the structs and classes with fields and methods
609                 // </summary>
610                 //
611                 // This is invoked after all interfaces, structs and classes
612                 // have been defined through `ResolveTree' 
613                 static public void PopulateTypes ()
614                 {
615                         TypeContainer root = Tree.Types;
616
617                         if (attribute_types != null)
618                                 foreach (TypeContainer tc in attribute_types)
619                                         tc.DefineMembers (root);
620
621                         if (type_container_resolve_order != null){
622                                 if (RootContext.StdLib){
623                                         foreach (TypeContainer tc in type_container_resolve_order)
624                                                 tc.DefineMembers (root);
625                                 } else {
626                                         foreach (TypeContainer tc in type_container_resolve_order) {
627                                                 // When compiling corlib, these types have already been
628                                                 // populated from BootCorlib_PopulateCoreTypes ().
629                                                 if (((tc.Name == "System.Object") ||
630                                                      (tc.Name == "System.Attribute") ||
631                                                      (tc.Name == "System.ValueType")))
632                                                 continue;
633
634                                                 tc.DefineMembers (root);
635                                         }
636                                 } 
637                         }
638
639                         ArrayList delegates = root.Delegates;
640                         if (delegates != null){
641                                 foreach (Delegate d in delegates)
642                                         if ((d.ModFlags & Modifiers.NEW) == 0)
643                                                 d.DefineMembers (root);
644                                         else
645                                                 Report1530 (d.Location);
646                         }
647
648                         ArrayList enums = root.Enums;
649                         if (enums != null){
650                                 foreach (Enum en in enums)
651                                         if ((en.ModFlags & Modifiers.NEW) == 0)
652                                                 en.DefineMembers (root);
653                                         else
654                                                 Report1530 (en.Location);
655                         }
656
657                         //
658                         // Check for cycles in the struct layout
659                         //
660                         if (type_container_resolve_order != null){
661                                 Hashtable seen = new Hashtable ();
662                                 foreach (TypeContainer tc in type_container_resolve_order)
663                                         TypeManager.CheckStructCycles (tc, seen);
664                         }
665                 }
666
667                 //
668                 // A generic hook delegate
669                 //
670                 public delegate void Hook ();
671
672                 //
673                 // A hook invoked when the code has been generated.
674                 //
675                 public static event Hook EmitCodeHook;
676
677                 //
678                 // DefineTypes is used to fill in the members of each type.
679                 //
680                 static public void DefineTypes ()
681                 {
682                         TypeContainer root = Tree.Types;
683
684                         if (attribute_types != null)
685                                 foreach (TypeContainer tc in attribute_types)
686                                         tc.Define ();
687
688                         if (type_container_resolve_order != null){
689                                 foreach (TypeContainer tc in type_container_resolve_order) {
690                                         // When compiling corlib, these types have already been
691                                         // populated from BootCorlib_PopulateCoreTypes ().
692                                         if (!RootContext.StdLib &&
693                                             ((tc.Name == "System.Object") ||
694                                              (tc.Name == "System.Attribute") ||
695                                              (tc.Name == "System.ValueType")))
696                                                 continue;
697
698                                         if ((tc.ModFlags & Modifiers.NEW) == 0)
699                                                 tc.Define ();
700                                 }
701                         }
702
703                         ArrayList delegates = root.Delegates;
704                         if (delegates != null){
705                                 foreach (Delegate d in delegates)
706                                         if ((d.ModFlags & Modifiers.NEW) == 0)
707                                                 d.Define ();
708                         }
709
710                         ArrayList enums = root.Enums;
711                         if (enums != null){
712                                 foreach (Enum en in enums)
713                                         if ((en.ModFlags & Modifiers.NEW) == 0)
714                                                 en.Define ();
715                         }
716                 }
717
718                 static public void EmitCode ()
719                 {
720                         if (attribute_types != null)
721                                 foreach (TypeContainer tc in attribute_types)
722                                         tc.EmitType ();
723
724                         CodeGen.Assembly.Emit (Tree.Types);
725                         CodeGen.Module.Emit (Tree.Types);
726                         
727                         if (Tree.Types.Enums != null) {
728                                 foreach (Enum e in Tree.Types.Enums)
729                                         e.Emit ();
730                         }
731
732                         if (type_container_resolve_order != null) {
733                                 foreach (TypeContainer tc in type_container_resolve_order)
734                                         tc.EmitType ();
735                         }
736                         
737                         if (Tree.Types.Delegates != null) {
738                                 foreach (Delegate d in Tree.Types.Delegates)
739                                         d.Emit ();
740                         }                       
741                         //
742                         // Run any hooks after all the types have been defined.
743                         // This is used to create nested auxiliary classes for example
744                         //
745
746                         if (EmitCodeHook != null)
747                                 EmitCodeHook ();
748                 }
749                 
750                 //
751                 // Public Field, used to track which method is the public entry
752                 // point.
753                 //
754                 static public MethodInfo EntryPoint;
755
756                 //
757                 // Track the location of the entry point.
758                 //
759                 static public Location EntryPointLocation;
760
761                 //
762                 // These are used to generate unique names on the structs and fields.
763                 //
764                 static int field_count;
765                 
766                 //
767                 // Makes an initialized struct, returns the field builder that
768                 // references the data.  Thanks go to Sergey Chaban for researching
769                 // how to do this.  And coming up with a shorter mechanism than I
770                 // was able to figure out.
771                 //
772                 // This works but makes an implicit public struct $ArrayType$SIZE and
773                 // makes the fields point to it.  We could get more control if we did
774                 // use instead:
775                 //
776                 // 1. DefineNestedType on the impl_details_class with our struct.
777                 //
778                 // 2. Define the field on the impl_details_class
779                 //
780                 static public FieldBuilder MakeStaticData (byte [] data)
781                 {
782                         FieldBuilder fb;
783                         
784                         if (impl_details_class == null){
785                                 impl_details_class = CodeGen.Module.Builder.DefineType (
786                                         "<PrivateImplementationDetails>",
787                                         TypeAttributes.NotPublic,
788                                         TypeManager.object_type);
789                                 
790                                 RegisterHelperClass (impl_details_class);
791                         }
792
793                         fb = impl_details_class.DefineInitializedData (
794                                 "$$field-" + (field_count++), data,
795                                 FieldAttributes.Static | FieldAttributes.Assembly);
796                         
797                         return fb;
798                 }
799         }
800 }
801               
802