mcs/mcs/codegen.cs

   1 //
   2 // codegen.cs: The code generator
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001, 2002, 2003 Ximian, Inc.
   8 // (C) 2004 Novell, Inc.
   9 //
  10 //#define PRODUCTION
  11 using System;
  12 using System.IO;
  13 using System.Collections;
  14 using System.Collections.Specialized;
  15 using System.Reflection;
  16 using System.Reflection.Emit;
  17 using System.Runtime.InteropServices;
  18 using System.Security;
  19 using System.Security.Cryptography;
  20 using System.Security.Permissions;
  21
  22 using Mono.Security.Cryptography;
  23
  24 namespace Mono.CSharp {
  25
  26         /// <summary>
  27         ///    Code generator class.
  28         /// </summary>
  29         public class CodeGen {
  30                 static AppDomain current_domain;
  31                 static public SymbolWriter SymbolWriter;
  32
  33                 public static AssemblyClass Assembly;
  34                 public static ModuleClass Module;
  35
  36                 static CodeGen ()
  37                 {
  38                         Reset ();
  39                 }
  40
  41                 public static void Reset ()
  42                 {
  43                         Assembly = new AssemblyClass ();
  44                         Module = new ModuleClass (RootContext.Unsafe);
  45                 }
  46
  47                 public static string Basename (string name)
  48                 {
  49                         int pos = name.LastIndexOf ('/');
  50
  51                         if (pos != -1)
  52                                 return name.Substring (pos + 1);
  53
  54                         pos = name.LastIndexOf ('\\');
  55                         if (pos != -1)
  56                                 return name.Substring (pos + 1);
  57
  58                         return name;
  59                 }
  60
  61                 public static string Dirname (string name)
  62                 {
  63                         int pos = name.LastIndexOf ('/');
  64
  65                         if (pos != -1)
  66                                 return name.Substring (0, pos);
  67
  68                         pos = name.LastIndexOf ('\\');
  69                         if (pos != -1)
  70                                 return name.Substring (0, pos);
  71
  72                         return ".";
  73                 }
  74
  75                 static public string FileName;
  76
  77                 //
  78                 // Initializes the symbol writer
  79                 //
  80                 static void InitializeSymbolWriter (string filename)
  81                 {
  82                         SymbolWriter = SymbolWriter.GetSymbolWriter (Module.Builder, filename);
  83
  84                         //
  85                         // If we got an ISymbolWriter instance, initialize it.
  86                         //
  87                         if (SymbolWriter == null) {
  88                                 Report.Warning (
  89                                         -18, "Could not find the symbol writer assembly (Mono.CompilerServices.SymbolWriter.dll). This is normally an installation problem. Please make sure to compile and install the mcs/class/Mono.CompilerServices.SymbolWriter directory.");
  90                                 return;
  91                         }
  92                 }
  93
  94                 //
  95                 // Initializes the code generator variables
  96                 //
  97                 static public bool Init (string name, string output, bool want_debugging_support)
  98                 {
  99                         FileName = output;
 100                         AssemblyName an = Assembly.GetAssemblyName (name, output);
 101                         if (an == null)
 102                                 return false;
 103
 104                         if (an.KeyPair != null) {
 105                                 // If we are going to strong name our assembly make
 106                                 // sure all its refs are strong named
 107                                 foreach (Assembly a in TypeManager.GetAssemblies ()) {
 108                                         AssemblyName ref_name = a.GetName ();
 109                                         byte [] b = ref_name.GetPublicKeyToken ();
 110                                         if (b == null || b.Length == 0) {
 111                                                 Report.Warning (1577, "Assembly generation failed " +
 112                                                                 "-- Referenced assembly '" +
 113                                                                 ref_name.Name +
 114                                                                 "' does not have a strong name.");
 115                                                 //Environment.Exit (1);
 116                                         }
 117                                 }
 118                         }
 119
 120                         current_domain = AppDomain.CurrentDomain;
 121
 122                         try {
 123                                 Assembly.Builder = current_domain.DefineDynamicAssembly (an,
 124                                         AssemblyBuilderAccess.Save, Dirname (name));
 125                         }
 126                         catch (ArgumentException) {
 127                                 // specified key may not be exportable outside it's container
 128                                 if (RootContext.StrongNameKeyContainer != null) {
 129                                         Report.Error (1548, "Could not access the key inside the container `" +
 130                                                 RootContext.StrongNameKeyContainer + "'.");
 131                                         Environment.Exit (1);
 132                                 }
 133                                 return false;
 134                         }
 135                         catch (CryptographicException) {
 136                                 if ((RootContext.StrongNameKeyContainer != null) || (RootContext.StrongNameKeyFile != null)) {
 137                                         Report.Error (1548, "Could not use the specified key to strongname the assembly.");
 138                                         Environment.Exit (1);
 139                                 }
 140                                 return false;
 141                         }
 142
 143                         //
 144                         // Pass a path-less name to DefineDynamicModule.  Wonder how
 145                         // this copes with output in different directories then.
 146                         // FIXME: figure out how this copes with --output /tmp/blah
 147                         //
 148                         // If the third argument is true, the ModuleBuilder will dynamically
 149                         // load the default symbol writer.
 150                         //
 151                         Module.Builder = Assembly.Builder.DefineDynamicModule (
 152                                 Basename (name), Basename (output), false);
 153
 154                         if (want_debugging_support)
 155                                 InitializeSymbolWriter (output);
 156
 157                         return true;
 158                 }
 159
 160                 static public void Save (string name)
 161                 {
 162                         try {
 163                                 Assembly.Builder.Save (Basename (name));
 164                         }
 165                         catch (COMException) {
 166                                 if ((RootContext.StrongNameKeyFile == null) || (!RootContext.StrongNameDelaySign))
 167                                         throw;
 168
 169                                 // FIXME: it seems Microsoft AssemblyBuilder doesn't like to delay sign assemblies
 170                                 Report.Error (1548, "Couldn't delay-sign the assembly with the '" +
 171                                         RootContext.StrongNameKeyFile +
 172                                         "', Use MCS with the Mono runtime or CSC to compile this assembly.");
 173                         }
 174                         catch (System.IO.IOException io) {
 175                                 Report.Error (16, "Could not write to file `"+name+"', cause: " + io.Message);
 176                         }
 177                         catch (System.UnauthorizedAccessException ua) {
 178                                 Report.Error (16, "Could not write to file `"+name+"', cause: " + ua.Message);
 179                         }
 180
 181                         if (SymbolWriter != null)
 182                                 SymbolWriter.WriteSymbolFile ();
 183                 }
 184         }
 185
 186         /// <summary>
 187         ///   An Emit Context is created for each body of code (from methods,
 188         ///   properties bodies, indexer bodies or constructor bodies)
 189         /// </summary>
 190         public class EmitContext {
 191                 public DeclSpace DeclSpace;
 192                 public DeclSpace TypeContainer;
 193                 public ILGenerator   ig;
 194
 195                 /// <summary>
 196                 ///   This variable tracks the `checked' state of the compilation,
 197                 ///   it controls whether we should generate code that does overflow
 198                 ///   checking, or if we generate code that ignores overflows.
 199                 ///
 200                 ///   The default setting comes from the command line option to generate
 201                 ///   checked or unchecked code plus any source code changes using the
 202                 ///   checked/unchecked statements or expressions.   Contrast this with
 203                 ///   the ConstantCheckState flag.
 204                 /// </summary>
 205
 206                 public bool CheckState;
 207
 208                 /// <summary>
 209                 ///   The constant check state is always set to `true' and cant be changed
 210                 ///   from the command line.  The source code can change this setting with
 211                 ///   the `checked' and `unchecked' statements and expressions.
 212                 /// </summary>
 213                 public bool ConstantCheckState;
 214
 215                 /// <summary>
 216                 ///   Whether we are emitting code inside a static or instance method
 217                 /// </summary>
 218                 public bool IsStatic;
 219
 220                 /// <summary>
 221                 ///   Whether the actual created method is static or instance method.
 222                 ///   Althoug the method might be declared as `static', if an anonymous
 223                 ///   method is involved, we might turn this into an instance method.
 224                 ///
 225                 ///   So this reflects the low-level staticness of the method, while
 226                 ///   IsStatic represents the semantic, high-level staticness.
 227                 /// </summary>
 228                 public bool MethodIsStatic;
 229
 230                 /// <summary>
 231                 ///   Whether we are emitting a field initializer
 232                 /// </summary>
 233                 public bool IsFieldInitializer;
 234
 235                 /// <summary>
 236                 ///   The value that is allowed to be returned or NULL if there is no
 237                 ///   return type.
 238                 /// </summary>
 239                 public Type ReturnType;
 240
 241                 /// <summary>
 242                 ///   Points to the Type (extracted from the TypeContainer) that
 243                 ///   declares this body of code
 244                 /// </summary>
 245                 public Type ContainerType;
 246
 247                 /// <summary>
 248                 ///   Whether this is generating code for a constructor
 249                 /// </summary>
 250                 public bool IsConstructor;
 251
 252                 /// <summary>
 253                 ///   Whether we're control flow analysis enabled
 254                 /// </summary>
 255                 public bool DoFlowAnalysis;
 256
 257                 /// <summary>
 258                 ///   Keeps track of the Type to LocalBuilder temporary storage created
 259                 ///   to store structures (used to compute the address of the structure
 260                 ///   value on structure method invocations)
 261                 /// </summary>
 262                 public Hashtable temporary_storage;
 263
 264                 public Block CurrentBlock;
 265
 266                 public int CurrentFile;
 267
 268                 /// <summary>
 269                 ///   The location where we store the return value.
 270                 /// </summary>
 271                 LocalBuilder return_value;
 272
 273                 /// <summary>
 274                 ///   The location where return has to jump to return the
 275                 ///   value
 276                 /// </summary>
 277                 public Label ReturnLabel;
 278
 279                 /// <summary>
 280                 ///   If we already defined the ReturnLabel
 281                 /// </summary>
 282                 public bool HasReturnLabel;
 283
 284                 /// <summary>
 285                 ///   Whether we are inside an iterator block.
 286                 /// </summary>
 287                 public bool InIterator;
 288
 289                 public bool IsLastStatement;
 290
 291                 /// <summary>
 292                 ///  Whether we are inside an unsafe block
 293                 /// </summary>
 294                 public bool InUnsafe;
 295
 296                 /// <summary>
 297                 ///  Whether we are in a `fixed' initialization
 298                 /// </summary>
 299                 public bool InFixedInitializer;
 300
 301                 public bool InRefOutArgumentResolving;
 302
 303                 public bool InCatch;
 304                 public bool InFinally;
 305
 306                 /// <summary>
 307                 ///  Whether we are inside an anonymous method.
 308                 /// </summary>
 309                 public AnonymousContainer CurrentAnonymousMethod;
 310
 311                 /// <summary>
 312                 ///   Location for this EmitContext
 313                 /// </summary>
 314                 public Location loc;
 315
 316                 /// <summary>
 317                 ///   Inside an enum definition, we do not resolve enumeration values
 318                 ///   to their enumerations, but rather to the underlying type/value
 319                 ///   This is so EnumVal + EnumValB can be evaluated.
 320                 ///
 321                 ///   There is no "E operator + (E x, E y)", so during an enum evaluation
 322                 ///   we relax the rules
 323                 /// </summary>
 324                 public bool InEnumContext;
 325
 326                 /// <summary>
 327                 ///   Anonymous methods can capture local variables and fields,
 328                 ///   this object tracks it.  It is copied from the TopLevelBlock
 329                 ///   field.
 330                 /// </summary>
 331                 public CaptureContext capture_context;
 332
 333                 /// <summary>
 334                 /// Trace when method is called and is obsolete then this member suppress message
 335                 /// when call is inside next [Obsolete] method or type.
 336                 /// </summary>
 337                 public bool TestObsoleteMethodUsage = true;
 338
 339                 /// <summary>
 340                 ///    The current iterator
 341                 /// </summary>
 342                 public Iterator CurrentIterator;
 343
 344                 /// <summary>
 345                 ///    Whether we are in the resolving stage or not
 346                 /// </summary>
 347                 enum Phase {
 348                         Created,
 349                         Resolving,
 350                         Emitting
 351                 }
 352
 353                 Phase current_phase;
 354                 FlowBranching current_flow_branching;
 355
 356                 static int next_id = 0;
 357                 int id = ++next_id;
 358
 359                 public override string ToString ()
 360                 {
 361                         return String.Format ("EmitContext ({0}:{1}:{2})", id,
 362                                               CurrentIterator, capture_context, loc);
 363                 }
 364
 365                 public EmitContext (DeclSpace parent, DeclSpace ds, Location l, ILGenerator ig,
 366                                     Type return_type, int code_flags, bool is_constructor)
 367                 {
 368                         this.ig = ig;
 369
 370                         TypeContainer = parent;
 371                         DeclSpace = ds;
 372                         CheckState = RootContext.Checked;
 373                         ConstantCheckState = true;
 374
 375                         IsStatic = (code_flags & Modifiers.STATIC) != 0;
 376                         MethodIsStatic = IsStatic;
 377                         InIterator = (code_flags & Modifiers.METHOD_YIELDS) != 0;
 378                         ReturnType = return_type;
 379                         IsConstructor = is_constructor;
 380                         CurrentBlock = null;
 381                         CurrentFile = 0;
 382                         current_phase = Phase.Created;
 383
 384                         if (parent != null){
 385                                 // Can only be null for the ResolveType contexts.
 386                                 ContainerType = parent.TypeBuilder;
 387                                 if (parent.UnsafeContext)
 388                                         InUnsafe = true;
 389                                 else
 390                                         InUnsafe = (code_flags & Modifiers.UNSAFE) != 0;
 391                         }
 392                         loc = l;
 393
 394                         if (ReturnType == TypeManager.void_type)
 395                                 ReturnType = null;
 396                 }
 397
 398                 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
 399                                     Type return_type, int code_flags, bool is_constructor)
 400                         : this (tc, tc, l, ig, return_type, code_flags, is_constructor)
 401                 {
 402                 }
 403
 404                 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
 405                                     Type return_type, int code_flags)
 406                         : this (tc, tc, l, ig, return_type, code_flags, false)
 407                 {
 408                 }
 409
 410                 public FlowBranching CurrentBranching {
 411                         get {
 412                                 return current_flow_branching;
 413                         }
 414                 }
 415
 416                 public bool HaveCaptureInfo {
 417                         get {
 418                                 return capture_context != null;
 419                         }
 420                 }
 421
 422                 // <summary>
 423                 //   Starts a new code branching.  This inherits the state of all local
 424                 //   variables and parameters from the current branching.
 425                 // </summary>
 426                 public FlowBranching StartFlowBranching (FlowBranching.BranchingType type, Location loc)
 427                 {
 428                         current_flow_branching = FlowBranching.CreateBranching (CurrentBranching, type, null, loc);
 429                         return current_flow_branching;
 430                 }
 431
 432                 // <summary>
 433                 //   Starts a new code branching for block `block'.
 434                 // </summary>
 435                 public FlowBranching StartFlowBranching (Block block)
 436                 {
 437                         FlowBranching.BranchingType type;
 438
 439                         if ((CurrentBranching != null) &&
 440                             (CurrentBranching.Type == FlowBranching.BranchingType.Switch))
 441                                 type = FlowBranching.BranchingType.SwitchSection;
 442                         else
 443                                 type = FlowBranching.BranchingType.Block;
 444
 445                         DoFlowAnalysis = true;
 446
 447                         current_flow_branching = FlowBranching.CreateBranching (
 448                                 CurrentBranching, type, block, block.StartLocation);
 449                         return current_flow_branching;
 450                 }
 451
 452                 public FlowBranchingException StartFlowBranching (ExceptionStatement stmt)
 453                 {
 454                         FlowBranchingException branching = new FlowBranchingException (
 455                                 CurrentBranching, stmt);
 456                         current_flow_branching = branching;
 457                         return branching;
 458                 }
 459
 460                 // <summary>
 461                 //   Ends a code branching.  Merges the state of locals and parameters
 462                 //   from all the children of the ending branching.
 463                 // </summary>
 464                 public FlowBranching.UsageVector DoEndFlowBranching ()
 465                 {
 466                         FlowBranching old = current_flow_branching;
 467                         current_flow_branching = current_flow_branching.Parent;
 468
 469                         return current_flow_branching.MergeChild (old);
 470                 }
 471
 472                 // <summary>
 473                 //   Ends a code branching.  Merges the state of locals and parameters
 474                 //   from all the children of the ending branching.
 475                 // </summary>
 476                 public FlowBranching.Reachability EndFlowBranching ()
 477                 {
 478                         FlowBranching.UsageVector vector = DoEndFlowBranching ();
 479
 480                         return vector.Reachability;
 481                 }
 482
 483                 // <summary>
 484                 //   Kills the current code branching.  This throws away any changed state
 485                 //   information and should only be used in case of an error.
 486                 // </summary>
 487                 public void KillFlowBranching ()
 488                 {
 489                         current_flow_branching = current_flow_branching.Parent;
 490                 }
 491
 492                 public void CaptureVariable (LocalInfo li)
 493                 {
 494                         capture_context.AddLocal (CurrentAnonymousMethod, li);
 495                         li.IsCaptured = true;
 496                 }
 497
 498                 public void CaptureParameter (string name, Type t, int idx)
 499                 {
 500                         capture_context.AddParameter (this, CurrentAnonymousMethod, name, t, idx);
 501                 }
 502
 503                 public void CaptureThis ()
 504                 {
 505                         capture_context.CaptureThis ();
 506                 }
 507
 508
 509                 //
 510                 // Use to register a field as captured
 511                 //
 512                 public void CaptureField (FieldExpr fe)
 513                 {
 514                         capture_context.AddField (fe);
 515                 }
 516
 517                 //
 518                 // Whether anonymous methods have captured variables
 519                 //
 520                 public bool HaveCapturedVariables ()
 521                 {
 522                         if (capture_context != null)
 523                                 return capture_context.HaveCapturedVariables;
 524                         return false;
 525                 }
 526
 527                 //
 528                 // Whether anonymous methods have captured fields or this.
 529                 //
 530                 public bool HaveCapturedFields ()
 531                 {
 532                         if (capture_context != null)
 533                                 return capture_context.HaveCapturedFields;
 534                         return false;
 535                 }
 536
 537                 //
 538                 // Emits the instance pointer for the host method
 539                 //
 540                 public void EmitMethodHostInstance (EmitContext target, AnonymousMethod am)
 541                 {
 542                         if (capture_context != null)
 543                                 capture_context.EmitMethodHostInstance (target, am);
 544                         else if (IsStatic)
 545                                 target.ig.Emit (OpCodes.Ldnull);
 546                         else
 547                                 target.ig.Emit (OpCodes.Ldarg_0);
 548                 }
 549
 550                 //
 551                 // Returns whether the `local' variable has been captured by an anonymous
 552                 // method
 553                 //
 554                 public bool IsCaptured (LocalInfo local)
 555                 {
 556                         return capture_context.IsCaptured (local);
 557                 }
 558
 559                 public bool IsParameterCaptured (string name)
 560                 {
 561                         if (capture_context != null)
 562                                 return capture_context.IsParameterCaptured (name);
 563                         return false;
 564                 }
 565
 566                 public void EmitMeta (ToplevelBlock b, InternalParameters ip)
 567                 {
 568                         if (capture_context != null)
 569                                 capture_context.EmitAnonymousHelperClasses (this);
 570                         b.EmitMeta (this);
 571
 572                         if (HasReturnLabel)
 573                                 ReturnLabel = ig.DefineLabel ();
 574                 }
 575
 576                 //
 577                 // Here until we can fix the problem with Mono.CSharp.Switch, which
 578                 // currently can not cope with ig == null during resolve (which must
 579                 // be fixed for switch statements to work on anonymous methods).
 580                 //
 581                 public void EmitTopBlock (IMethodData md, ToplevelBlock block, InternalParameters ip)
 582                 {
 583                         if (block == null)
 584                                 return;
 585
 586                         bool unreachable;
 587
 588                         if (ResolveTopBlock (null, block, ip, md, out unreachable)){
 589                                 EmitMeta (block, ip);
 590
 591                                 current_phase = Phase.Emitting;
 592                                 EmitResolvedTopBlock (block, unreachable);
 593                         }
 594                 }
 595
 596                 bool resolved;
 597
 598                 public bool ResolveTopBlock (EmitContext anonymous_method_host, ToplevelBlock block,
 599                                              InternalParameters ip, IMethodData md, out bool unreachable)
 600                 {
 601                         current_phase = Phase.Resolving;
 602
 603                         unreachable = false;
 604
 605                         if (resolved)
 606                                 return true;
 607
 608                         capture_context = block.CaptureContext;
 609
 610                         if (!Location.IsNull (loc))
 611                                 CurrentFile = loc.File;
 612
 613 #if PRODUCTION
 614                         try {
 615 #endif
 616                                 if (!block.ResolveMeta (this, ip))
 617                                         return false;
 618
 619                                         bool old_do_flow_analysis = DoFlowAnalysis;
 620                                         DoFlowAnalysis = true;
 621
 622                                         if (anonymous_method_host != null)
 623                                                 current_flow_branching = FlowBranching.CreateBranching (
 624                                                         anonymous_method_host.CurrentBranching,
 625                                                         FlowBranching.BranchingType.Block, block, loc);
 626                                         else
 627                                                 current_flow_branching = block.TopLevelBranching;
 628
 629                                         if (!block.Resolve (this)) {
 630                                                 current_flow_branching = null;
 631                                                 DoFlowAnalysis = old_do_flow_analysis;
 632                                                 return false;
 633                                         }
 634
 635                                         FlowBranching.Reachability reachability = current_flow_branching.MergeTopBlock ();
 636                                         current_flow_branching = null;
 637
 638                                         DoFlowAnalysis = old_do_flow_analysis;
 639
 640                                         if (reachability.AlwaysReturns ||
 641                                             reachability.AlwaysThrows ||
 642                                             reachability.IsUnreachable)
 643                                                 unreachable = true;
 644 #if PRODUCTION
 645                         } catch (Exception e) {
 646                                         Console.WriteLine ("Exception caught by the compiler while compiling:");
 647                                         Console.WriteLine ("   Block that caused the problem begin at: " + loc);
 648
 649                                         if (CurrentBlock != null){
 650                                                 Console.WriteLine ("                     Block being compiled: [{0},{1}]",
 651                                                                    CurrentBlock.StartLocation, CurrentBlock.EndLocation);
 652                                         }
 653                                         Console.WriteLine (e.GetType ().FullName + ": " + e.Message);
 654                                         throw;
 655                         }
 656 #endif
 657
 658                         if (ReturnType != null && !unreachable) {
 659                                 if (CurrentAnonymousMethod == null) {
 660                                         Report.Error (161, md.Location, "`{0}': not all code paths return a value", md.GetSignatureForError ());
 661                                         return false;
 662                                 } else if (!CurrentAnonymousMethod.IsIterator) {
 663                                         Report.Error (1643, CurrentAnonymousMethod.Location, "Not all code paths return a value in anonymous method of type `{0}'",
 664                                                 CurrentAnonymousMethod.GetSignatureForError ());
 665                                         return false;
 666                                 }
 667                         }
 668
 669                         block.CompleteContexts ();
 670                         resolved = true;
 671                         return true;
 672                 }
 673
 674                 public void EmitResolvedTopBlock (ToplevelBlock block, bool unreachable)
 675                 {
 676                         if (block != null)
 677                                 block.Emit (this);
 678
 679                         if (HasReturnLabel)
 680                                 ig.MarkLabel (ReturnLabel);
 681
 682                         if (return_value != null){
 683                                 ig.Emit (OpCodes.Ldloc, return_value);
 684                                 ig.Emit (OpCodes.Ret);
 685                         } else {
 686                                 //
 687                                 // If `HasReturnLabel' is set, then we already emitted a
 688                                 // jump to the end of the method, so we must emit a `ret'
 689                                 // there.
 690                                 //
 691                                 // Unfortunately, System.Reflection.Emit automatically emits
 692                                 // a leave to the end of a finally block.  This is a problem
 693                                 // if no code is following the try/finally block since we may
 694                                 // jump to a point after the end of the method.
 695                                 // As a workaround, we're always creating a return label in
 696                                 // this case.
 697                                 //
 698
 699                                 bool in_iterator = (CurrentAnonymousMethod != null) &&
 700                                         CurrentAnonymousMethod.IsIterator && InIterator;
 701
 702                                 if ((block != null) && block.IsDestructor) {
 703                                         // Nothing to do; S.R.E automatically emits a leave.
 704                                 } else if (HasReturnLabel || (!unreachable && !in_iterator)) {
 705                                         if (ReturnType != null)
 706                                                 ig.Emit (OpCodes.Ldloc, TemporaryReturn ());
 707                                         ig.Emit (OpCodes.Ret);
 708                                 }
 709                         }
 710
 711                         //
 712                         // Close pending helper classes if we are the toplevel
 713                         //
 714                         if (capture_context != null && capture_context.ParentToplevel == null)
 715                                 capture_context.CloseAnonymousHelperClasses ();
 716                 }
 717
 718                 /// <summary>
 719                 ///   This is called immediately before emitting an IL opcode to tell the symbol
 720                 ///   writer to which source line this opcode belongs.
 721                 /// </summary>
 722                 public void Mark (Location loc, bool check_file)
 723                 {
 724                         if ((CodeGen.SymbolWriter == null) || Location.IsNull (loc))
 725                                 return;
 726
 727                         if (check_file && (CurrentFile != loc.File))
 728                                 return;
 729
 730                         CodeGen.SymbolWriter.MarkSequencePoint (ig, loc.Row, 0);
 731                 }
 732
 733                 public void DefineLocalVariable (string name, LocalBuilder builder)
 734                 {
 735                         if (CodeGen.SymbolWriter == null)
 736                                 return;
 737
 738                         CodeGen.SymbolWriter.DefineLocalVariable (name, builder);
 739                 }
 740
 741                 public void BeginScope ()
 742                 {
 743                         ig.BeginScope();
 744
 745                         if (CodeGen.SymbolWriter != null)
 746                                 CodeGen.SymbolWriter.OpenScope(ig);
 747                 }
 748
 749                 public void EndScope ()
 750                 {
 751                         ig.EndScope();
 752
 753                         if (CodeGen.SymbolWriter != null)
 754                                 CodeGen.SymbolWriter.CloseScope(ig);
 755                 }
 756
 757                 /// <summary>
 758                 ///   Returns a temporary storage for a variable of type t as
 759                 ///   a local variable in the current body.
 760                 /// </summary>
 761                 public LocalBuilder GetTemporaryLocal (Type t)
 762                 {
 763                         LocalBuilder location = null;
 764
 765                         if (temporary_storage != null){
 766                                 object o = temporary_storage [t];
 767                                 if (o != null){
 768                                         if (o is ArrayList){
 769                                                 ArrayList al = (ArrayList) o;
 770
 771                                                 for (int i = 0; i < al.Count; i++){
 772                                                         if (al [i] != null){
 773                                                                 location = (LocalBuilder) al [i];
 774                                                                 al [i] = null;
 775                                                                 break;
 776                                                         }
 777                                                 }
 778                                         } else
 779                                                 location = (LocalBuilder) o;
 780                                         if (location != null)
 781                                                 return location;
 782                                 }
 783                         }
 784
 785                         return ig.DeclareLocal (t);
 786                 }
 787
 788                 public void FreeTemporaryLocal (LocalBuilder b, Type t)
 789                 {
 790                         if (temporary_storage == null){
 791                                 temporary_storage = new Hashtable ();
 792                                 temporary_storage [t] = b;
 793                                 return;
 794                         }
 795                         object o = temporary_storage [t];
 796                         if (o == null){
 797                                 temporary_storage [t] = b;
 798                                 return;
 799                         }
 800                         if (o is ArrayList){
 801                                 ArrayList al = (ArrayList) o;
 802                                 for (int i = 0; i < al.Count; i++){
 803                                         if (al [i] == null){
 804                                                 al [i] = b;
 805                                                 return;
 806                                         }
 807                                 }
 808                                 al.Add (b);
 809                                 return;
 810                         }
 811                         ArrayList replacement = new ArrayList ();
 812                         replacement.Add (o);
 813                         temporary_storage.Remove (t);
 814                         temporary_storage [t] = replacement;
 815                 }
 816
 817                 /// <summary>
 818                 ///   Current loop begin and end labels.
 819                 /// </summary>
 820                 public Label LoopBegin, LoopEnd;
 821
 822                 /// <summary>
 823                 ///   Default target in a switch statement.   Only valid if
 824                 ///   InSwitch is true
 825                 /// </summary>
 826                 public Label DefaultTarget;
 827
 828                 /// <summary>
 829                 ///   If this is non-null, points to the current switch statement
 830                 /// </summary>
 831                 public Switch Switch;
 832
 833                 /// <summary>
 834                 ///   ReturnValue creates on demand the LocalBuilder for the
 835                 ///   return value from the function.  By default this is not
 836                 ///   used.  This is only required when returns are found inside
 837                 ///   Try or Catch statements.
 838                 ///
 839                 ///   This method is typically invoked from the Emit phase, so
 840                 ///   we allow the creation of a return label if it was not
 841                 ///   requested during the resolution phase.   Could be cleaned
 842                 ///   up, but it would replicate a lot of logic in the Emit phase
 843                 ///   of the code that uses it.
 844                 /// </summary>
 845                 public LocalBuilder TemporaryReturn ()
 846                 {
 847                         if (return_value == null){
 848                                 return_value = ig.DeclareLocal (ReturnType);
 849                                 if (!HasReturnLabel){
 850                                         ReturnLabel = ig.DefineLabel ();
 851                                         HasReturnLabel = true;
 852                                 }
 853                         }
 854
 855                         return return_value;
 856                 }
 857
 858                 /// <summary>
 859                 ///   This method is used during the Resolution phase to flag the
 860                 ///   need to define the ReturnLabel
 861                 /// </summary>
 862                 public void NeedReturnLabel ()
 863                 {
 864                         if (current_phase != Phase.Resolving){
 865                                 //
 866                                 // The reason is that the `ReturnLabel' is declared between
 867                                 // resolution and emission
 868                                 //
 869                                 throw new Exception ("NeedReturnLabel called from Emit phase, should only be called during Resolve");
 870                         }
 871
 872                         if (!InIterator && !HasReturnLabel)
 873                                 HasReturnLabel = true;
 874                 }
 875
 876                 //
 877                 // Emits the proper object to address fields on a remapped
 878                 // variable/parameter to field in anonymous-method/iterator proxy classes.
 879                 //
 880                 public void EmitThis ()
 881                 {
 882                         ig.Emit (OpCodes.Ldarg_0);
 883                         if (capture_context != null && CurrentAnonymousMethod != null){
 884                                 ScopeInfo si = CurrentAnonymousMethod.Scope;
 885                                 while (si != null){
 886                                         if (si.ParentLink != null)
 887                                                 ig.Emit (OpCodes.Ldfld, si.ParentLink);
 888                                         if (si.THIS != null){
 889                                                 ig.Emit (OpCodes.Ldfld, si.THIS);
 890                                                 break;
 891                                         }
 892                                         si = si.ParentScope;
 893                                 }
 894                         }
 895                 }
 896
 897                 //
 898                 // Emits the code necessary to load the instance required
 899                 // to access the captured LocalInfo
 900                 //
 901                 public void EmitCapturedVariableInstance (LocalInfo li)
 902                 {
 903                         if (capture_context == null)
 904                                 throw new Exception ("Calling EmitCapturedContext when there is no capture_context");
 905
 906                         capture_context.EmitCapturedVariableInstance (this, li, CurrentAnonymousMethod);
 907                 }
 908
 909                 public void EmitParameter (string name)
 910                 {
 911                         capture_context.EmitParameter (this, name);
 912                 }
 913
 914                 public void EmitAssignParameter (string name, Expression source, bool leave_copy, bool prepare_for_load)
 915                 {
 916                         capture_context.EmitAssignParameter (this, name, source, leave_copy, prepare_for_load);
 917                 }
 918
 919                 public void EmitAddressOfParameter (string name)
 920                 {
 921                         capture_context.EmitAddressOfParameter (this, name);
 922                 }
 923
 924                 public Expression GetThis (Location loc)
 925                 {
 926                         This my_this;
 927                         if (CurrentBlock != null)
 928                                 my_this = new This (CurrentBlock, loc);
 929                         else
 930                                 my_this = new This (loc);
 931
 932                         if (!my_this.ResolveBase (this))
 933                                 my_this = null;
 934
 935                         return my_this;
 936                 }
 937         }
 938
 939
 940         public abstract class CommonAssemblyModulClass: Attributable {
 941                 protected CommonAssemblyModulClass ():
 942                         base (null)
 943                 {
 944                 }
 945
 946                 public void AddAttributes (ArrayList attrs)
 947                 {
 948                         if (OptAttributes == null) {
 949                                 OptAttributes = new Attributes (attrs);
 950                                 return;
 951                         }
 952                         OptAttributes.AddAttributes (attrs);
 953                 }
 954
 955                 public virtual void Emit (TypeContainer tc)
 956                 {
 957                         if (OptAttributes == null)
 958                                 return;
 959
 960                         EmitContext ec = new EmitContext (tc, Mono.CSharp.Location.Null, null, null, 0, false);
 961                         OptAttributes.Emit (ec, this);
 962                 }
 963
 964                 protected Attribute ResolveAttribute (Type a_type)
 965                 {
 966                         if (OptAttributes == null)
 967                                 return null;
 968
 969                         // Ensure that we only have GlobalAttributes, since the Search below isn't safe with other types.
 970                         if (!OptAttributes.CheckTargets (this))
 971                                 return null;
 972
 973                         EmitContext temp_ec = new EmitContext (RootContext.Tree.Types, Mono.CSharp.Location.Null, null, null, 0, false);
 974                         Attribute a = OptAttributes.Search (a_type, temp_ec);
 975                         if (a != null) {
 976                                 a.Resolve (temp_ec);
 977                         }
 978                         return a;
 979                 }
 980         }
 981
 982         public class AssemblyClass: CommonAssemblyModulClass {
 983                 // TODO: make it private and move all builder based methods here
 984                 public AssemblyBuilder Builder;
 985                 bool is_cls_compliant;
 986                 public Attribute ClsCompliantAttribute;
 987
 988                 ListDictionary declarative_security;
 989
 990                 // Module is here just because of error messages
 991                 static string[] attribute_targets = new string [] { "assembly", "module" };
 992
 993                 public AssemblyClass (): base ()
 994                 {
 995                         is_cls_compliant = false;
 996                 }
 997
 998                 public bool IsClsCompliant {
 999                         get {
1000                                 return is_cls_compliant;
1001                         }
1002                 }
1003
1004                 public override AttributeTargets AttributeTargets {
1005                         get {
1006                                 return AttributeTargets.Assembly;
1007                         }
1008                 }
1009
1010                 public override bool IsClsCompliaceRequired(DeclSpace ds)
1011                 {
1012                         return is_cls_compliant;
1013                 }
1014
1015                 public void ResolveClsCompliance ()
1016                 {
1017                         ClsCompliantAttribute = ResolveAttribute (TypeManager.cls_compliant_attribute_type);
1018                         if (ClsCompliantAttribute == null)
1019                                 return;
1020
1021                         is_cls_compliant = ClsCompliantAttribute.GetClsCompliantAttributeValue (null);
1022                 }
1023
1024                 // fix bug #56621
1025                 private void SetPublicKey (AssemblyName an, byte[] strongNameBlob)
1026                 {
1027                         try {
1028                                 // check for possible ECMA key
1029                                 if (strongNameBlob.Length == 16) {
1030                                         // will be rejected if not "the" ECMA key
1031                                         an.SetPublicKey (strongNameBlob);
1032                                 }
1033                                 else {
1034                                         // take it, with or without, a private key
1035                                         RSA rsa = CryptoConvert.FromCapiKeyBlob (strongNameBlob);
1036                                         // and make sure we only feed the public part to Sys.Ref
1037                                         byte[] publickey = CryptoConvert.ToCapiPublicKeyBlob (rsa);
1038
1039                                         // AssemblyName.SetPublicKey requires an additional header
1040                                         byte[] publicKeyHeader = new byte [12] { 0x00, 0x24, 0x00, 0x00, 0x04, 0x80, 0x00, 0x00, 0x94, 0x00, 0x00, 0x00 };
1041
1042                                         byte[] encodedPublicKey = new byte [12 + publickey.Length];
1043                                         Buffer.BlockCopy (publicKeyHeader, 0, encodedPublicKey, 0, 12);
1044                                         Buffer.BlockCopy (publickey, 0, encodedPublicKey, 12, publickey.Length);
1045                                         an.SetPublicKey (encodedPublicKey);
1046                                 }
1047                         }
1048                         catch (Exception) {
1049                                 Error_AssemblySigning ("The speficied file `" + RootContext.StrongNameKeyFile + "' is incorrectly encoded");
1050                                 Environment.Exit (1);
1051                         }
1052                 }
1053
1054                 // TODO: rewrite this code (to kill N bugs and make it faster) and use standard ApplyAttribute way.
1055                 public AssemblyName GetAssemblyName (string name, string output)
1056                 {
1057                         if (OptAttributes != null) {
1058                                 foreach (Attribute a in OptAttributes.Attrs) {
1059                                         // cannot rely on any resolve-based members before you call Resolve
1060                                         if (a.ExplicitTarget == null || a.ExplicitTarget != "assembly")
1061                                                 continue;
1062
1063                                         // TODO: This code is buggy: comparing Attribute name without resolving is wrong.
1064                                         //       However, this is invoked by CodeGen.Init, when none of the namespaces
1065                                         //       are loaded yet.
1066                                         switch (a.Name) {
1067                                                 case "AssemblyKeyFile":
1068                                                 case "AssemblyKeyFileAttribute":
1069                                                 case "System.Reflection.AssemblyKeyFileAttribute":
1070                                                         if (RootContext.StrongNameKeyFile != null) {
1071                                                                 Report.SymbolRelatedToPreviousError (a.Location, a.Name);
1072                                                                 Report.Warning (1616, "Option `{0}' overrides attribute `{1}' given in a source file or added module",
1073                                     "keyfile", "System.Reflection.AssemblyKeyFileAttribute");
1074                                                         }
1075                                                         else {
1076                                                                 string value = a.GetString ();
1077                                                                 if (value != String.Empty)
1078                                                                         RootContext.StrongNameKeyFile = value;
1079                                                         }
1080                                                         break;
1081                                                 case "AssemblyKeyName":
1082                                                 case "AssemblyKeyNameAttribute":
1083                                                 case "System.Reflection.AssemblyKeyNameAttribute":
1084                                                         if (RootContext.StrongNameKeyContainer != null) {
1085                                                                 Report.SymbolRelatedToPreviousError (a.Location, a.Name);
1086                                                                 Report.Warning (1616, "Option `{0}' overrides attribute `{1}' given in a source file or added module",
1087                                                                         "keycontainer", "System.Reflection.AssemblyKeyNameAttribute");
1088                                                         }
1089                                                         else {
1090                                                                 string value = a.GetString ();
1091                                                                 if (value != String.Empty)
1092                                                                         RootContext.StrongNameKeyContainer = value;
1093                                                         }
1094                                                         break;
1095                                                 case "AssemblyDelaySign":
1096                                                 case "AssemblyDelaySignAttribute":
1097                                                 case "System.Reflection.AssemblyDelaySignAttribute":
1098                                                         RootContext.StrongNameDelaySign = a.GetBoolean ();
1099                                                         break;
1100                                         }
1101                                 }
1102                         }
1103
1104                         AssemblyName an = new AssemblyName ();
1105                         an.Name = Path.GetFileNameWithoutExtension (name);
1106
1107                         // note: delay doesn't apply when using a key container
1108                         if (RootContext.StrongNameKeyContainer != null) {
1109                                 an.KeyPair = new StrongNameKeyPair (RootContext.StrongNameKeyContainer);
1110                                 return an;
1111                         }
1112
1113                         // strongname is optional
1114                         if (RootContext.StrongNameKeyFile == null)
1115                                 return an;
1116
1117                         string AssemblyDir = Path.GetDirectoryName (output);
1118
1119                         // the StrongName key file may be relative to (a) the compiled
1120                         // file or (b) to the output assembly. See bugzilla #55320
1121                         // http://bugzilla.ximian.com/show_bug.cgi?id=55320
1122
1123                         // (a) relative to the compiled file
1124                         string filename = Path.GetFullPath (RootContext.StrongNameKeyFile);
1125                         bool exist = File.Exists (filename);
1126                         if ((!exist) && (AssemblyDir != null) && (AssemblyDir != String.Empty)) {
1127                                 // (b) relative to the outputed assembly
1128                                 filename = Path.GetFullPath (Path.Combine (AssemblyDir, RootContext.StrongNameKeyFile));
1129                                 exist = File.Exists (filename);
1130                         }
1131
1132                         if (exist) {
1133                                 using (FileStream fs = new FileStream (filename, FileMode.Open, FileAccess.Read)) {
1134                                         byte[] snkeypair = new byte [fs.Length];
1135                                         fs.Read (snkeypair, 0, snkeypair.Length);
1136
1137                                         if (RootContext.StrongNameDelaySign) {
1138                                                 // delayed signing - DO NOT include private key
1139                                                 SetPublicKey (an, snkeypair);
1140                                         }
1141                                         else {
1142                                                 // no delay so we make sure we have the private key
1143                                                 try {
1144                                                         CryptoConvert.FromCapiPrivateKeyBlob (snkeypair);
1145                                                         an.KeyPair = new StrongNameKeyPair (snkeypair);
1146                                                 }
1147                                                 catch (CryptographicException) {
1148                                                         if (snkeypair.Length == 16) {
1149                                                                 // error # is different for ECMA key
1150                                                                 Report.Error (1606, "Could not sign the assembly. " +
1151                                                                         "ECMA key can only be used to delay-sign assemblies");
1152                                                         }
1153                                                         else {
1154                                                                 Error_AssemblySigning ("The speficied file `" + RootContext.StrongNameKeyFile + "' does not have a private key");
1155                                                         }
1156                                                         return null;
1157                                                 }
1158                                         }
1159                                 }
1160                         }
1161                         else {
1162                                 Error_AssemblySigning ("The speficied file `" + RootContext.StrongNameKeyFile + "' does not exist");
1163                                 return null;
1164                         }
1165                         return an;
1166                 }
1167
1168                 void Error_AssemblySigning (string text)
1169                 {
1170                         Report.Error (1548, "Error during assembly signing. " + text);
1171                 }
1172
1173                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
1174                 {
1175                         if (a.Type.IsSubclassOf (TypeManager.security_attr_type) && a.CheckSecurityActionValidity (true)) {
1176                                 if (declarative_security == null)
1177                                         declarative_security = new ListDictionary ();
1178
1179                                 a.ExtractSecurityPermissionSet (declarative_security);
1180                                 return;
1181                         }
1182
1183                         Builder.SetCustomAttribute (customBuilder);
1184                 }
1185
1186                 public override void Emit (TypeContainer tc)
1187                 {
1188                         base.Emit (tc);
1189
1190                         if (declarative_security != null) {
1191
1192                                 MethodInfo add_permission = typeof (AssemblyBuilder).GetMethod ("AddPermissionRequests", BindingFlags.Instance | BindingFlags.NonPublic);
1193                                 object builder_instance = Builder;
1194
1195                                 try {
1196                                         // Microsoft runtime hacking
1197                                         if (add_permission == null) {
1198                                                 Type assembly_builder = typeof (AssemblyBuilder).Assembly.GetType ("System.Reflection.Emit.AssemblyBuilderData");
1199                                                 add_permission = assembly_builder.GetMethod ("AddPermissionRequests", BindingFlags.Instance | BindingFlags.NonPublic);
1200
1201                                                 FieldInfo fi = typeof (AssemblyBuilder).GetField ("m_assemblyData", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.GetField);
1202                                                 builder_instance = fi.GetValue (Builder);
1203                                         }
1204
1205                                         object[] args = new object [] { declarative_security [SecurityAction.RequestMinimum],
1206                                                                                                   declarative_security [SecurityAction.RequestOptional],
1207                                                                                                   declarative_security [SecurityAction.RequestRefuse] };
1208                                         add_permission.Invoke (builder_instance, args);
1209                                 }
1210                                 catch {
1211                                         Report.RuntimeMissingSupport (Location.Null, "assembly permission setting");
1212                                 }
1213                         }
1214                 }
1215
1216                 public override string[] ValidAttributeTargets {
1217                         get {
1218                                 return attribute_targets;
1219                         }
1220                 }
1221         }
1222
1223         public class ModuleClass: CommonAssemblyModulClass {
1224                 // TODO: make it private and move all builder based methods here
1225                 public ModuleBuilder Builder;
1226                 bool m_module_is_unsafe;
1227
1228                 public CharSet DefaultCharSet = CharSet.Ansi;
1229                 public TypeAttributes DefaultCharSetType = TypeAttributes.AnsiClass;
1230
1231                 static string[] attribute_targets = new string [] { "module" };
1232
1233                 public ModuleClass (bool is_unsafe)
1234                 {
1235                         m_module_is_unsafe = is_unsafe;
1236                 }
1237
1238                 public override AttributeTargets AttributeTargets {
1239                         get {
1240                                 return AttributeTargets.Module;
1241                         }
1242                 }
1243
1244                 public override bool IsClsCompliaceRequired(DeclSpace ds)
1245                 {
1246                         return CodeGen.Assembly.IsClsCompliant;
1247                 }
1248
1249                 public override void Emit (TypeContainer tc)
1250                 {
1251                         base.Emit (tc);
1252
1253                         if (!m_module_is_unsafe)
1254                                 return;
1255
1256                         if (TypeManager.unverifiable_code_ctor == null) {
1257                                 Console.WriteLine ("Internal error ! Cannot set unverifiable code attribute.");
1258                                 return;
1259                         }
1260
1261                         Builder.SetCustomAttribute (new CustomAttributeBuilder (TypeManager.unverifiable_code_ctor, new object [0]));
1262                 }
1263
1264                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
1265                 {
1266                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
1267                                 if (CodeGen.Assembly.ClsCompliantAttribute == null) {
1268                                         Report.Warning (3012, a.Location, "You must specify the CLSCompliant attribute on the assembly, not the module, to enable CLS compliance checking");
1269                                 }
1270                                 else if (CodeGen.Assembly.IsClsCompliant != a.GetBoolean ()) {
1271                                         Report.SymbolRelatedToPreviousError (CodeGen.Assembly.ClsCompliantAttribute.Location, CodeGen.Assembly.ClsCompliantAttribute.Name);
1272                                         Report.Error (3017, a.Location, "You cannot specify the CLSCompliant attribute on a module that differs from the CLSCompliant attribute on the assembly");
1273                                         return;
1274                                 }
1275                         }
1276
1277                         Builder.SetCustomAttribute (customBuilder);
1278                 }
1279
1280                 /// <summary>
1281                 /// It is called very early therefore can resolve only predefined attributes
1282                 /// </summary>
1283                 public void ResolveAttributes ()
1284                 {
1285 #if NET_2_0
1286                         Attribute a = ResolveAttribute (TypeManager.default_charset_type);
1287                         if (a != null) {
1288                                 DefaultCharSet = a.GetCharSetValue ();
1289                                 switch (DefaultCharSet) {
1290                                         case CharSet.Ansi:
1291                                         case CharSet.None:
1292                                                 break;
1293                                         case CharSet.Auto:
1294                                                 DefaultCharSetType = TypeAttributes.AutoClass;
1295                                                 break;
1296                                         case CharSet.Unicode:
1297                                                 DefaultCharSetType = TypeAttributes.UnicodeClass;
1298                                                 break;
1299                                         default:
1300                                                 Report.Error (1724, a.Location, "Value specified for the argument to 'System.Runtime.InteropServices.DefaultCharSetAttribute' is not valid");
1301                                                 break;
1302                                 }
1303                         }
1304 #endif
1305                 }
1306
1307                 public override string[] ValidAttributeTargets {
1308                         get {
1309                                 return attribute_targets;
1310                         }
1311                 }
1312         }
1313 }