mcs/gmcs/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                 ///   We are resolving a class'es base class and interfaces.
 237                 /// </summary>
 238                 public bool ResolvingTypeTree;
 239
 240                 /// <summary>
 241                 ///   The value that is allowed to be returned or NULL if there is no
 242                 ///   return type.
 243                 /// </summary>
 244                 public Type ReturnType;
 245
 246                 /// <summary>
 247                 ///   Points to the Type (extracted from the TypeContainer) that
 248                 ///   declares this body of code
 249                 /// </summary>
 250                 public Type ContainerType;
 251
 252                 /// <summary>
 253                 ///   Whether this is generating code for a constructor
 254                 /// </summary>
 255                 public bool IsConstructor;
 256
 257                 /// <summary>
 258                 ///   Whether we're control flow analysis enabled
 259                 /// </summary>
 260                 public bool DoFlowAnalysis;
 261
 262                 /// <summary>
 263                 ///   Keeps track of the Type to LocalBuilder temporary storage created
 264                 ///   to store structures (used to compute the address of the structure
 265                 ///   value on structure method invocations)
 266                 /// </summary>
 267                 public Hashtable temporary_storage;
 268
 269                 public Block CurrentBlock;
 270
 271                 public int CurrentFile;
 272
 273                 /// <summary>
 274                 ///   The location where we store the return value.
 275                 /// </summary>
 276                 LocalBuilder return_value;
 277
 278                 /// <summary>
 279                 ///   The location where return has to jump to return the
 280                 ///   value
 281                 /// </summary>
 282                 public Label ReturnLabel;
 283
 284                 /// <summary>
 285                 ///   If we already defined the ReturnLabel
 286                 /// </summary>
 287                 public bool HasReturnLabel;
 288
 289                 /// <summary>
 290                 ///   Whether we are inside an iterator block.
 291                 /// </summary>
 292                 public bool InIterator;
 293
 294                 public bool IsLastStatement;
 295
 296                 /// <summary>
 297                 ///  Whether we are inside an unsafe block
 298                 /// </summary>
 299                 public bool InUnsafe;
 300
 301                 /// <summary>
 302                 ///  Whether we are in a `fixed' initialization
 303                 /// </summary>
 304                 public bool InFixedInitializer;
 305
 306                 public bool InRefOutArgumentResolving;
 307
 308                 public bool InCatch;
 309                 public bool InFinally;
 310
 311                 /// <summary>
 312                 ///  Whether we are inside an anonymous method.
 313                 /// </summary>
 314                 public AnonymousContainer CurrentAnonymousMethod;
 315
 316                 /// <summary>
 317                 ///   Location for this EmitContext
 318                 /// </summary>
 319                 public Location loc;
 320
 321                 /// <summary>
 322                 ///   Inside an enum definition, we do not resolve enumeration values
 323                 ///   to their enumerations, but rather to the underlying type/value
 324                 ///   This is so EnumVal + EnumValB can be evaluated.
 325                 ///
 326                 ///   There is no "E operator + (E x, E y)", so during an enum evaluation
 327                 ///   we relax the rules
 328                 /// </summary>
 329                 public bool InEnumContext;
 330
 331                 /// <summary>
 332                 ///   Anonymous methods can capture local variables and fields,
 333                 ///   this object tracks it.  It is copied from the TopLevelBlock
 334                 ///   field.
 335                 /// </summary>
 336                 public CaptureContext capture_context;
 337
 338                 /// <summary>
 339                 /// Trace when method is called and is obsolete then this member suppress message
 340                 /// when call is inside next [Obsolete] method or type.
 341                 /// </summary>
 342                 public bool TestObsoleteMethodUsage = true;
 343
 344                 /// <summary>
 345                 ///    The current iterator
 346                 /// </summary>
 347                 public Iterator CurrentIterator {
 348                         get {
 349                                 if (CurrentAnonymousMethod != null)
 350                                         return CurrentAnonymousMethod.Iterator;
 351                                 else
 352                                         return null;
 353                         }
 354                 }
 355
 356                 /// <summary>
 357                 ///    Whether we are in the resolving stage or not
 358                 /// </summary>
 359                 enum Phase {
 360                         Created,
 361                         Resolving,
 362                         Emitting
 363                 }
 364
 365                 Phase current_phase;
 366                 FlowBranching current_flow_branching;
 367
 368                 static int next_id = 0;
 369                 int id = ++next_id;
 370
 371                 public override string ToString ()
 372                 {
 373                         return String.Format ("EmitContext ({0}:{1}:{2})", id,
 374                                               CurrentIterator, capture_context, loc);
 375                 }
 376
 377                 public EmitContext (DeclSpace parent, DeclSpace ds, Location l, ILGenerator ig,
 378                                     Type return_type, int code_flags, bool is_constructor)
 379                 {
 380                         this.ig = ig;
 381
 382                         TypeContainer = parent;
 383                         DeclSpace = ds;
 384                         CheckState = RootContext.Checked;
 385                         ConstantCheckState = true;
 386
 387                         if ((return_type is TypeBuilder) && return_type.IsGenericTypeDefinition)
 388                                 throw new InternalErrorException ();
 389
 390                         IsStatic = (code_flags & Modifiers.STATIC) != 0;
 391                         MethodIsStatic = IsStatic;
 392                         InIterator = (code_flags & Modifiers.METHOD_YIELDS) != 0;
 393                         ReturnType = return_type;
 394                         IsConstructor = is_constructor;
 395                         CurrentBlock = null;
 396                         CurrentFile = 0;
 397                         current_phase = Phase.Created;
 398
 399                         if (parent != null){
 400                                 // Can only be null for the ResolveType contexts.
 401                                 ContainerType = parent.TypeBuilder;
 402                                 if (parent.UnsafeContext)
 403                                         InUnsafe = true;
 404                                 else
 405                                         InUnsafe = (code_flags & Modifiers.UNSAFE) != 0;
 406                         }
 407                         loc = l;
 408
 409                         if (ReturnType == TypeManager.void_type)
 410                                 ReturnType = null;
 411                 }
 412
 413                 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
 414                                     Type return_type, int code_flags, bool is_constructor)
 415                         : this (tc, tc, l, ig, return_type, code_flags, is_constructor)
 416                 {
 417                 }
 418
 419                 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
 420                                     Type return_type, int code_flags)
 421                         : this (tc, tc, l, ig, return_type, code_flags, false)
 422                 {
 423                 }
 424
 425                 public FlowBranching CurrentBranching {
 426                         get {
 427                                 return current_flow_branching;
 428                         }
 429                 }
 430
 431                 public bool HaveCaptureInfo {
 432                         get {
 433                                 return capture_context != null;
 434                         }
 435                 }
 436
 437                 // <summary>
 438                 //   Starts a new code branching.  This inherits the state of all local
 439                 //   variables and parameters from the current branching.
 440                 // </summary>
 441                 public FlowBranching StartFlowBranching (FlowBranching.BranchingType type, Location loc)
 442                 {
 443                         current_flow_branching = FlowBranching.CreateBranching (CurrentBranching, type, null, loc);
 444                         return current_flow_branching;
 445                 }
 446
 447                 // <summary>
 448                 //   Starts a new code branching for block `block'.
 449                 // </summary>
 450                 public FlowBranching StartFlowBranching (Block block)
 451                 {
 452                         FlowBranching.BranchingType type;
 453
 454                         if ((CurrentBranching != null) &&
 455                             (CurrentBranching.Type == FlowBranching.BranchingType.Switch))
 456                                 type = FlowBranching.BranchingType.SwitchSection;
 457                         else
 458                                 type = FlowBranching.BranchingType.Block;
 459
 460                         DoFlowAnalysis = true;
 461
 462                         current_flow_branching = FlowBranching.CreateBranching (
 463                                 CurrentBranching, type, block, block.StartLocation);
 464                         return current_flow_branching;
 465                 }
 466
 467                 public FlowBranchingException StartFlowBranching (ExceptionStatement stmt)
 468                 {
 469                         FlowBranchingException branching = new FlowBranchingException (
 470                                 CurrentBranching, stmt);
 471                         current_flow_branching = branching;
 472                         return branching;
 473                 }
 474
 475                 // <summary>
 476                 //   Ends a code branching.  Merges the state of locals and parameters
 477                 //   from all the children of the ending branching.
 478                 // </summary>
 479                 public FlowBranching.UsageVector DoEndFlowBranching ()
 480                 {
 481                         FlowBranching old = current_flow_branching;
 482                         current_flow_branching = current_flow_branching.Parent;
 483
 484                         return current_flow_branching.MergeChild (old);
 485                 }
 486
 487                 // <summary>
 488                 //   Ends a code branching.  Merges the state of locals and parameters
 489                 //   from all the children of the ending branching.
 490                 // </summary>
 491                 public FlowBranching.Reachability EndFlowBranching ()
 492                 {
 493                         FlowBranching.UsageVector vector = DoEndFlowBranching ();
 494
 495                         return vector.Reachability;
 496                 }
 497
 498                 // <summary>
 499                 //   Kills the current code branching.  This throws away any changed state
 500                 //   information and should only be used in case of an error.
 501                 // </summary>
 502                 public void KillFlowBranching ()
 503                 {
 504                         current_flow_branching = current_flow_branching.Parent;
 505                 }
 506
 507                 public void CaptureVariable (LocalInfo li)
 508                 {
 509                         capture_context.AddLocal (CurrentAnonymousMethod, li);
 510                         li.IsCaptured = true;
 511                 }
 512
 513                 public void CaptureParameter (string name, Type t, int idx)
 514                 {
 515                         capture_context.AddParameter (this, CurrentAnonymousMethod, name, t, idx);
 516                 }
 517
 518                 public void CaptureThis ()
 519                 {
 520                         capture_context.CaptureThis ();
 521                 }
 522
 523
 524                 //
 525                 // Use to register a field as captured
 526                 //
 527                 public void CaptureField (FieldExpr fe)
 528                 {
 529                         capture_context.AddField (fe);
 530                 }
 531
 532                 //
 533                 // Whether anonymous methods have captured variables
 534                 //
 535                 public bool HaveCapturedVariables ()
 536                 {
 537                         if (capture_context != null)
 538                                 return capture_context.HaveCapturedVariables;
 539                         return false;
 540                 }
 541
 542                 //
 543                 // Whether anonymous methods have captured fields or this.
 544                 //
 545                 public bool HaveCapturedFields ()
 546                 {
 547                         if (capture_context != null)
 548                                 return capture_context.HaveCapturedFields;
 549                         return false;
 550                 }
 551
 552                 //
 553                 // Emits the instance pointer for the host method
 554                 //
 555                 public void EmitMethodHostInstance (EmitContext target, AnonymousMethod am)
 556                 {
 557                         if (capture_context != null)
 558                                 capture_context.EmitMethodHostInstance (target, am);
 559                         else if (IsStatic)
 560                                 target.ig.Emit (OpCodes.Ldnull);
 561                         else
 562                                 target.ig.Emit (OpCodes.Ldarg_0);
 563                 }
 564
 565                 //
 566                 // Returns whether the `local' variable has been captured by an anonymous
 567                 // method
 568                 //
 569                 public bool IsCaptured (LocalInfo local)
 570                 {
 571                         return capture_context.IsCaptured (local);
 572                 }
 573
 574                 public bool IsParameterCaptured (string name)
 575                 {
 576                         if (capture_context != null)
 577                                 return capture_context.IsParameterCaptured (name);
 578                         return false;
 579                 }
 580
 581                 public void EmitMeta (ToplevelBlock b, InternalParameters ip)
 582                 {
 583                         if (capture_context != null)
 584                                 capture_context.EmitAnonymousHelperClasses (this);
 585                         b.EmitMeta (this);
 586
 587                         if (HasReturnLabel)
 588                                 ReturnLabel = ig.DefineLabel ();
 589                 }
 590
 591                 //
 592                 // Here until we can fix the problem with Mono.CSharp.Switch, which
 593                 // currently can not cope with ig == null during resolve (which must
 594                 // be fixed for switch statements to work on anonymous methods).
 595                 //
 596                 public void EmitTopBlock (IMethodData md, ToplevelBlock block, InternalParameters ip)
 597                 {
 598                         if (block == null)
 599                                 return;
 600
 601                         bool unreachable;
 602
 603                         if (ResolveTopBlock (null, block, ip, md, out unreachable)){
 604                                 EmitMeta (block, ip);
 605
 606                                 current_phase = Phase.Emitting;
 607                                 EmitResolvedTopBlock (block, unreachable);
 608                         }
 609                 }
 610
 611                 bool resolved;
 612
 613                 public bool ResolveTopBlock (EmitContext anonymous_method_host, ToplevelBlock block,
 614                                              InternalParameters ip, IMethodData md, out bool unreachable)
 615                 {
 616                         current_phase = Phase.Resolving;
 617
 618                         unreachable = false;
 619
 620                         if (resolved)
 621                                 return true;
 622
 623                         capture_context = block.CaptureContext;
 624
 625                         if (!Location.IsNull (loc))
 626                                 CurrentFile = loc.File;
 627
 628 #if PRODUCTION
 629                         try {
 630 #endif
 631                                 if (!block.ResolveMeta (this, ip))
 632                                         return false;
 633
 634                                 bool old_do_flow_analysis = DoFlowAnalysis;
 635                                 DoFlowAnalysis = true;
 636
 637                                 if (anonymous_method_host != null)
 638                                         current_flow_branching = FlowBranching.CreateBranching (
 639                                                 anonymous_method_host.CurrentBranching,
 640                                                 FlowBranching.BranchingType.Block, block, loc);
 641                                 else
 642                                         current_flow_branching = block.TopLevelBranching;
 643
 644                                 if (!block.Resolve (this)) {
 645                                         current_flow_branching = null;
 646                                         DoFlowAnalysis = old_do_flow_analysis;
 647                                         return false;
 648                                 }
 649
 650                                 FlowBranching.Reachability reachability = current_flow_branching.MergeTopBlock ();
 651                                 current_flow_branching = null;
 652
 653                                 DoFlowAnalysis = old_do_flow_analysis;
 654
 655                                 if (reachability.AlwaysReturns ||
 656                                     reachability.AlwaysThrows ||
 657                                     reachability.IsUnreachable)
 658                                         unreachable = true;
 659 #if PRODUCTION
 660                         } catch (Exception e) {
 661                                         Console.WriteLine ("Exception caught by the compiler while compiling:");
 662                                         Console.WriteLine ("   Block that caused the problem begin at: " + loc);
 663
 664                                         if (CurrentBlock != null){
 665                                                 Console.WriteLine ("                     Block being compiled: [{0},{1}]",
 666                                                                    CurrentBlock.StartLocation, CurrentBlock.EndLocation);
 667                                         }
 668                                         Console.WriteLine (e.GetType ().FullName + ": " + e.Message);
 669                                 throw;
 670                         }
 671 #endif
 672
 673                         if (ReturnType != null && !unreachable) {
 674                                 if (CurrentAnonymousMethod == null) {
 675                                         Report.Error (161, md.Location, "`{0}': not all code paths return a value", md.GetSignatureForError ());
 676                                         return false;
 677                                 } else if (!CurrentAnonymousMethod.IsIterator) {
 678                                         Report.Error (1643, CurrentAnonymousMethod.Location, "Not all code paths return a value in anonymous method of type `{0}'",
 679                                                 CurrentAnonymousMethod.GetSignatureForError ());
 680                                         return false;
 681                                 }
 682                         }
 683
 684                         block.CompleteContexts ();
 685                         resolved = true;
 686                         return true;
 687                 }
 688
 689                 public void EmitResolvedTopBlock (ToplevelBlock block, bool unreachable)
 690                 {
 691                         if (block != null)
 692                                 block.Emit (this);
 693
 694                         if (HasReturnLabel)
 695                                 ig.MarkLabel (ReturnLabel);
 696
 697                         if (return_value != null){
 698                                 ig.Emit (OpCodes.Ldloc, return_value);
 699                                 ig.Emit (OpCodes.Ret);
 700                         } else {
 701                                 //
 702                                 // If `HasReturnLabel' is set, then we already emitted a
 703                                 // jump to the end of the method, so we must emit a `ret'
 704                                 // there.
 705                                 //
 706                                 // Unfortunately, System.Reflection.Emit automatically emits
 707                                 // a leave to the end of a finally block.  This is a problem
 708                                 // if no code is following the try/finally block since we may
 709                                 // jump to a point after the end of the method.
 710                                 // As a workaround, we're always creating a return label in
 711                                 // this case.
 712                                 //
 713
 714                                 bool in_iterator = (CurrentAnonymousMethod != null) &&
 715                                         CurrentAnonymousMethod.IsIterator && InIterator;
 716
 717                                 if ((block != null) && block.IsDestructor) {
 718                                         // Nothing to do; S.R.E automatically emits a leave.
 719                                 } else if (HasReturnLabel || (!unreachable && !in_iterator)) {
 720                                         if (ReturnType != null)
 721                                                 ig.Emit (OpCodes.Ldloc, TemporaryReturn ());
 722                                         ig.Emit (OpCodes.Ret);
 723                                 }
 724                         }
 725
 726                         //
 727                         // Close pending helper classes if we are the toplevel
 728                         //
 729                         if (capture_context != null && capture_context.ParentToplevel == null)
 730                                 capture_context.CloseAnonymousHelperClasses ();
 731                 }
 732
 733                 /// <summary>
 734                 ///   This is called immediately before emitting an IL opcode to tell the symbol
 735                 ///   writer to which source line this opcode belongs.
 736                 /// </summary>
 737                 public void Mark (Location loc, bool check_file)
 738                 {
 739                         if ((CodeGen.SymbolWriter == null) || Location.IsNull (loc))
 740                                 return;
 741
 742                         if (check_file && (CurrentFile != loc.File))
 743                                 return;
 744
 745                         CodeGen.SymbolWriter.MarkSequencePoint (ig, loc.Row, 0);
 746                 }
 747
 748                 public void DefineLocalVariable (string name, LocalBuilder builder)
 749                 {
 750                         if (CodeGen.SymbolWriter == null)
 751                                 return;
 752
 753                         CodeGen.SymbolWriter.DefineLocalVariable (name, builder);
 754                 }
 755
 756                 public void BeginScope ()
 757                 {
 758                         ig.BeginScope();
 759
 760                         if (CodeGen.SymbolWriter != null)
 761                                 CodeGen.SymbolWriter.OpenScope(ig);
 762                 }
 763
 764                 public void EndScope ()
 765                 {
 766                         ig.EndScope();
 767
 768                         if (CodeGen.SymbolWriter != null)
 769                                 CodeGen.SymbolWriter.CloseScope(ig);
 770                 }
 771
 772                 /// <summary>
 773                 ///   Returns a temporary storage for a variable of type t as
 774                 ///   a local variable in the current body.
 775                 /// </summary>
 776                 public LocalBuilder GetTemporaryLocal (Type t)
 777                 {
 778                         LocalBuilder location = null;
 779
 780                         if (temporary_storage != null){
 781                                 object o = temporary_storage [t];
 782                                 if (o != null){
 783                                         if (o is ArrayList){
 784                                                 ArrayList al = (ArrayList) o;
 785
 786                                                 for (int i = 0; i < al.Count; i++){
 787                                                         if (al [i] != null){
 788                                                                 location = (LocalBuilder) al [i];
 789                                                                 al [i] = null;
 790                                                                 break;
 791                                                         }
 792                                                 }
 793                                         } else
 794                                                 location = (LocalBuilder) o;
 795                                         if (location != null)
 796                                                 return location;
 797                                 }
 798                         }
 799
 800                         return ig.DeclareLocal (t);
 801                 }
 802
 803                 public void FreeTemporaryLocal (LocalBuilder b, Type t)
 804                 {
 805                         if (temporary_storage == null){
 806                                 temporary_storage = new Hashtable ();
 807                                 temporary_storage [t] = b;
 808                                 return;
 809                         }
 810                         object o = temporary_storage [t];
 811                         if (o == null){
 812                                 temporary_storage [t] = b;
 813                                 return;
 814                         }
 815                         if (o is ArrayList){
 816                                 ArrayList al = (ArrayList) o;
 817                                 for (int i = 0; i < al.Count; i++){
 818                                         if (al [i] == null){
 819                                                 al [i] = b;
 820                                                 return;
 821                                         }
 822                                 }
 823                                 al.Add (b);
 824                                 return;
 825                         }
 826                         ArrayList replacement = new ArrayList ();
 827                         replacement.Add (o);
 828                         temporary_storage.Remove (t);
 829                         temporary_storage [t] = replacement;
 830                 }
 831
 832                 /// <summary>
 833                 ///   Current loop begin and end labels.
 834                 /// </summary>
 835                 public Label LoopBegin, LoopEnd;
 836
 837                 /// <summary>
 838                 ///   Default target in a switch statement.   Only valid if
 839                 ///   InSwitch is true
 840                 /// </summary>
 841                 public Label DefaultTarget;
 842
 843                 /// <summary>
 844                 ///   If this is non-null, points to the current switch statement
 845                 /// </summary>
 846                 public Switch Switch;
 847
 848                 /// <summary>
 849                 ///   ReturnValue creates on demand the LocalBuilder for the
 850                 ///   return value from the function.  By default this is not
 851                 ///   used.  This is only required when returns are found inside
 852                 ///   Try or Catch statements.
 853                 ///
 854                 ///   This method is typically invoked from the Emit phase, so
 855                 ///   we allow the creation of a return label if it was not
 856                 ///   requested during the resolution phase.   Could be cleaned
 857                 ///   up, but it would replicate a lot of logic in the Emit phase
 858                 ///   of the code that uses it.
 859                 /// </summary>
 860                 public LocalBuilder TemporaryReturn ()
 861                 {
 862                         if (return_value == null){
 863                                 return_value = ig.DeclareLocal (ReturnType);
 864                                 if (!HasReturnLabel){
 865                                 ReturnLabel = ig.DefineLabel ();
 866                                 HasReturnLabel = true;
 867                         }
 868                         }
 869
 870                         return return_value;
 871                 }
 872
 873                 /// <summary>
 874                 ///   This method is used during the Resolution phase to flag the
 875                 ///   need to define the ReturnLabel
 876                 /// </summary>
 877                 public void NeedReturnLabel ()
 878                 {
 879                         if (current_phase != Phase.Resolving){
 880                                 //
 881                                 // The reason is that the `ReturnLabel' is declared between
 882                                 // resolution and emission
 883                                 //
 884                                 throw new Exception ("NeedReturnLabel called from Emit phase, should only be called during Resolve");
 885                         }
 886
 887                         if (!InIterator && !HasReturnLabel)
 888                                 HasReturnLabel = true;
 889                 }
 890
 891                 //
 892                 // Emits the proper object to address fields on a remapped
 893                 // variable/parameter to field in anonymous-method/iterator proxy classes.
 894                 //
 895                 public void EmitThis ()
 896                 {
 897                         ig.Emit (OpCodes.Ldarg_0);
 898                         if (capture_context != null && CurrentAnonymousMethod != null){
 899                                 ScopeInfo si = CurrentAnonymousMethod.Scope;
 900                                 while (si != null){
 901                                         if (si.ParentLink != null)
 902                                                 ig.Emit (OpCodes.Ldfld, si.ParentLink);
 903                                         if (si.THIS != null){
 904                                                 ig.Emit (OpCodes.Ldfld, si.THIS);
 905                                                 break;
 906                                         }
 907                                         si = si.ParentScope;
 908                                 }
 909                         }
 910                 }
 911
 912                 //
 913                 // Emits the code necessary to load the instance required
 914                 // to access the captured LocalInfo
 915                 //
 916                 public void EmitCapturedVariableInstance (LocalInfo li)
 917                 {
 918                         if (capture_context == null)
 919                                 throw new Exception ("Calling EmitCapturedContext when there is no capture_context");
 920
 921                         capture_context.EmitCapturedVariableInstance (this, li, CurrentAnonymousMethod);
 922                 }
 923
 924                 public void EmitParameter (string name)
 925                 {
 926                         capture_context.EmitParameter (this, name);
 927                 }
 928
 929                 public void EmitAssignParameter (string name, Expression source, bool leave_copy, bool prepare_for_load)
 930                 {
 931                         capture_context.EmitAssignParameter (this, name, source, leave_copy, prepare_for_load);
 932                 }
 933
 934                 public void EmitAddressOfParameter (string name)
 935                 {
 936                         capture_context.EmitAddressOfParameter (this, name);
 937                 }
 938
 939                 public Expression GetThis (Location loc)
 940                 {
 941                         This my_this;
 942                         if (CurrentBlock != null)
 943                                 my_this = new This (CurrentBlock, loc);
 944                         else
 945                                 my_this = new This (loc);
 946
 947                         if (!my_this.ResolveBase (this))
 948                                 my_this = null;
 949
 950                         return my_this;
 951                 }
 952         }
 953
 954
 955         public abstract class CommonAssemblyModulClass: Attributable {
 956                 protected CommonAssemblyModulClass ():
 957                         base (null)
 958                 {
 959                 }
 960
 961                 public void AddAttributes (ArrayList attrs)
 962                 {
 963                         if (OptAttributes == null) {
 964                                 OptAttributes = new Attributes (attrs);
 965                                 return;
 966                         }
 967                         OptAttributes.AddAttributes (attrs);
 968                 }
 969
 970                 public virtual void Emit (TypeContainer tc)
 971                 {
 972                         if (OptAttributes == null)
 973                                 return;
 974
 975                         EmitContext ec = new EmitContext (tc, Mono.CSharp.Location.Null, null, null, 0, false);
 976                         OptAttributes.Emit (ec, this);
 977                 }
 978
 979                 protected Attribute ResolveAttribute (Type a_type)
 980                 {
 981                         if (OptAttributes == null)
 982                                 return null;
 983
 984                         // Ensure that we only have GlobalAttributes, since the Search below isn't safe with other types.
 985                         if (!OptAttributes.CheckTargets (this))
 986                                 return null;
 987
 988                         EmitContext temp_ec = new EmitContext (RootContext.Tree.Types, Mono.CSharp.Location.Null, null, null, 0, false);
 989                         Attribute a = OptAttributes.Search (a_type, temp_ec);
 990                         if (a != null) {
 991                                 a.Resolve (temp_ec);
 992                         }
 993                         return a;
 994                 }
 995         }
 996
 997         public class AssemblyClass: CommonAssemblyModulClass {
 998                 // TODO: make it private and move all builder based methods here
 999                 public AssemblyBuilder Builder;
1000
1001                 bool is_cls_compliant;
1002                 public Attribute ClsCompliantAttribute;
1003
1004                 ListDictionary declarative_security;
1005
1006                 // Module is here just because of error messages
1007                 static string[] attribute_targets = new string [] { "assembly", "module" };
1008
1009                 public AssemblyClass (): base ()
1010                 {
1011                         is_cls_compliant = false;
1012                 }
1013
1014                 public bool IsClsCompliant {
1015                         get {
1016                                 return is_cls_compliant;
1017                         }
1018                         }
1019
1020                 public override AttributeTargets AttributeTargets {
1021                         get {
1022                                 return AttributeTargets.Assembly;
1023                         }
1024                 }
1025
1026                 public override bool IsClsComplianceRequired(DeclSpace ds)
1027                 {
1028                         return is_cls_compliant;
1029                 }
1030
1031                 public void ResolveClsCompliance ()
1032                 {
1033                         ClsCompliantAttribute = ResolveAttribute (TypeManager.cls_compliant_attribute_type);
1034                         if (ClsCompliantAttribute == null)
1035                                 return;
1036
1037                         is_cls_compliant = ClsCompliantAttribute.GetClsCompliantAttributeValue (null);
1038                 }
1039
1040                 // fix bug #56621
1041                 private void SetPublicKey (AssemblyName an, byte[] strongNameBlob)
1042                 {
1043                         try {
1044                                 // check for possible ECMA key
1045                                 if (strongNameBlob.Length == 16) {
1046                                         // will be rejected if not "the" ECMA key
1047                                         an.SetPublicKey (strongNameBlob);
1048                                 }
1049                                 else {
1050                                         // take it, with or without, a private key
1051                                         RSA rsa = CryptoConvert.FromCapiKeyBlob (strongNameBlob);
1052                                         // and make sure we only feed the public part to Sys.Ref
1053                                         byte[] publickey = CryptoConvert.ToCapiPublicKeyBlob (rsa);
1054
1055                                         // AssemblyName.SetPublicKey requires an additional header
1056                                         byte[] publicKeyHeader = new byte [12] { 0x00, 0x24, 0x00, 0x00, 0x04, 0x80, 0x00, 0x00, 0x94, 0x00, 0x00, 0x00 };
1057
1058                                         byte[] encodedPublicKey = new byte [12 + publickey.Length];
1059                                         Buffer.BlockCopy (publicKeyHeader, 0, encodedPublicKey, 0, 12);
1060                                         Buffer.BlockCopy (publickey, 0, encodedPublicKey, 12, publickey.Length);
1061                                         an.SetPublicKey (encodedPublicKey);
1062                                 }
1063                         }
1064                         catch (Exception) {
1065                                 Error_AssemblySigning ("The speficied file `" + RootContext.StrongNameKeyFile + "' is incorrectly encoded");
1066                                 Environment.Exit (1);
1067                         }
1068                 }
1069
1070                 // TODO: rewrite this code (to kill N bugs and make it faster) and use standard ApplyAttribute way.
1071                 public AssemblyName GetAssemblyName (string name, string output)
1072                 {
1073                         if (OptAttributes != null) {
1074                                foreach (Attribute a in OptAttributes.Attrs) {
1075                                        // cannot rely on any resolve-based members before you call Resolve
1076                                        if (a.ExplicitTarget == null || a.ExplicitTarget != "assembly")
1077                                                continue;
1078
1079                                         // TODO: This code is buggy: comparing Attribute name without resolving is wrong.
1080                                         //       However, this is invoked by CodeGen.Init, when none of the namespaces
1081                                         //       are loaded yet.
1082                                         switch (a.Name) {
1083                                                 case "AssemblyKeyFile":
1084                                                case "AssemblyKeyFileAttribute":
1085                                                case "System.Reflection.AssemblyKeyFileAttribute":
1086                                                         if (RootContext.StrongNameKeyFile != null) {
1087                                                                 Report.SymbolRelatedToPreviousError (a.Location, a.Name);
1088                                                                 Report.Warning (1616, "Option `{0}' overrides attribute `{1}' given in a source file or added module",
1089                                     "keyfile", "System.Reflection.AssemblyKeyFileAttribute");
1090                                                         }
1091                                                         else {
1092                                                                 string value = a.GetString ();
1093                                                                 if (value != String.Empty)
1094                                                                         RootContext.StrongNameKeyFile = value;
1095                                                         }
1096                                                         break;
1097                                                 case "AssemblyKeyName":
1098                                                case "AssemblyKeyNameAttribute":
1099                                                case "System.Reflection.AssemblyKeyNameAttribute":
1100                                                         if (RootContext.StrongNameKeyContainer != null) {
1101                                                                 Report.SymbolRelatedToPreviousError (a.Location, a.Name);
1102                                                                 Report.Warning (1616, "Option `{0}' overrides attribute `{1}' given in a source file or added module",
1103                                                                         "keycontainer", "System.Reflection.AssemblyKeyNameAttribute");
1104                                                         }
1105                                                         else {
1106                                                                 string value = a.GetString ();
1107                                                                 if (value != String.Empty)
1108                                                                         RootContext.StrongNameKeyContainer = value;
1109                                                         }
1110                                                         break;
1111                                                 case "AssemblyDelaySign":
1112                                                case "AssemblyDelaySignAttribute":
1113                                                case "System.Reflection.AssemblyDelaySignAttribute":
1114                                                         RootContext.StrongNameDelaySign = a.GetBoolean ();
1115                                                         break;
1116                                         }
1117                                 }
1118                         }
1119
1120                         AssemblyName an = new AssemblyName ();
1121                         an.Name = Path.GetFileNameWithoutExtension (name);
1122
1123                         // note: delay doesn't apply when using a key container
1124                         if (RootContext.StrongNameKeyContainer != null) {
1125                                 an.KeyPair = new StrongNameKeyPair (RootContext.StrongNameKeyContainer);
1126                                 return an;
1127                         }
1128
1129                         // strongname is optional
1130                         if (RootContext.StrongNameKeyFile == null)
1131                                 return an;
1132
1133                         string AssemblyDir = Path.GetDirectoryName (output);
1134
1135                         // the StrongName key file may be relative to (a) the compiled
1136                         // file or (b) to the output assembly. See bugzilla #55320
1137                         // http://bugzilla.ximian.com/show_bug.cgi?id=55320
1138
1139                         // (a) relative to the compiled file
1140                         string filename = Path.GetFullPath (RootContext.StrongNameKeyFile);
1141                         bool exist = File.Exists (filename);
1142                         if ((!exist) && (AssemblyDir != null) && (AssemblyDir != String.Empty)) {
1143                                 // (b) relative to the outputed assembly
1144                                 filename = Path.GetFullPath (Path.Combine (AssemblyDir, RootContext.StrongNameKeyFile));
1145                                 exist = File.Exists (filename);
1146                         }
1147
1148                         if (exist) {
1149                                 using (FileStream fs = new FileStream (filename, FileMode.Open, FileAccess.Read)) {
1150                                         byte[] snkeypair = new byte [fs.Length];
1151                                         fs.Read (snkeypair, 0, snkeypair.Length);
1152
1153                                         if (RootContext.StrongNameDelaySign) {
1154                                                 // delayed signing - DO NOT include private key
1155                                                 SetPublicKey (an, snkeypair);
1156                                         }
1157                                         else {
1158                                                 // no delay so we make sure we have the private key
1159                                                 try {
1160                                                         CryptoConvert.FromCapiPrivateKeyBlob (snkeypair);
1161                                                         an.KeyPair = new StrongNameKeyPair (snkeypair);
1162                                                 }
1163                                                 catch (CryptographicException) {
1164                                                         if (snkeypair.Length == 16) {
1165                                                                 // error # is different for ECMA key
1166                                                                 Report.Error (1606, "Could not sign the assembly. " +
1167                                                                         "ECMA key can only be used to delay-sign assemblies");
1168                                                         }
1169                                                         else {
1170                                                                 Error_AssemblySigning ("The speficied file `" + RootContext.StrongNameKeyFile + "' does not have a private key");
1171                                                         }
1172                                                         return null;
1173                                                 }
1174                                         }
1175                                 }
1176                         }
1177                         else {
1178                                 Error_AssemblySigning ("The speficied file `" + RootContext.StrongNameKeyFile + "' does not exist");
1179                                 return null;
1180                         }
1181                         return an;
1182                 }
1183
1184                 void Error_AssemblySigning (string text)
1185                 {
1186                         Report.Error (1548, "Error during assembly signing. " + text);
1187                 }
1188
1189                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
1190                 {
1191                         if (a.Type.IsSubclassOf (TypeManager.security_attr_type) && a.CheckSecurityActionValidity (true)) {
1192                                 if (declarative_security == null)
1193                                         declarative_security = new ListDictionary ();
1194
1195                                 a.ExtractSecurityPermissionSet (declarative_security);
1196                                 return;
1197                         }
1198
1199                         Builder.SetCustomAttribute (customBuilder);
1200                 }
1201
1202                 public override void Emit (TypeContainer tc)
1203                 {
1204                         base.Emit (tc);
1205
1206                         if (declarative_security != null) {
1207
1208                                 MethodInfo add_permission = typeof (AssemblyBuilder).GetMethod ("AddPermissionRequests", BindingFlags.Instance | BindingFlags.NonPublic);
1209                                 object builder_instance = Builder;
1210
1211                                 try {
1212                                         // Microsoft runtime hacking
1213                                         if (add_permission == null) {
1214                                                 Type assembly_builder = typeof (AssemblyBuilder).Assembly.GetType ("System.Reflection.Emit.AssemblyBuilderData");
1215                                                 add_permission = assembly_builder.GetMethod ("AddPermissionRequests", BindingFlags.Instance | BindingFlags.NonPublic);
1216
1217                                                 FieldInfo fi = typeof (AssemblyBuilder).GetField ("m_assemblyData", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.GetField);
1218                                                 builder_instance = fi.GetValue (Builder);
1219                                         }
1220
1221                                         object[] args = new object [] { declarative_security [SecurityAction.RequestMinimum],
1222                                                                                                   declarative_security [SecurityAction.RequestOptional],
1223                                                                                                   declarative_security [SecurityAction.RequestRefuse] };
1224                                         add_permission.Invoke (builder_instance, args);
1225                                 }
1226                                 catch {
1227                                         Report.RuntimeMissingSupport (Location.Null, "assembly permission setting");
1228                                 }
1229                         }
1230                 }
1231
1232                 public override string[] ValidAttributeTargets {
1233                         get {
1234                                 return attribute_targets;
1235                         }
1236                 }
1237         }
1238
1239         public class ModuleClass: CommonAssemblyModulClass {
1240                 // TODO: make it private and move all builder based methods here
1241                 public ModuleBuilder Builder;
1242                 bool m_module_is_unsafe;
1243
1244                 public CharSet DefaultCharSet = CharSet.Ansi;
1245                 public TypeAttributes DefaultCharSetType = TypeAttributes.AnsiClass;
1246
1247                 static string[] attribute_targets = new string [] { "module" };
1248
1249                 public ModuleClass (bool is_unsafe)
1250                 {
1251                         m_module_is_unsafe = is_unsafe;
1252                 }
1253
1254                 public override AttributeTargets AttributeTargets {
1255                         get {
1256                                 return AttributeTargets.Module;
1257                         }
1258                 }
1259
1260                 public override bool IsClsComplianceRequired(DeclSpace ds)
1261                 {
1262                         return CodeGen.Assembly.IsClsCompliant;
1263                         }
1264
1265                 public override void Emit (TypeContainer tc)
1266                 {
1267                         base.Emit (tc);
1268
1269                         if (!m_module_is_unsafe)
1270                                 return;
1271
1272                         if (TypeManager.unverifiable_code_ctor == null) {
1273                                 Console.WriteLine ("Internal error ! Cannot set unverifiable code attribute.");
1274                                 return;
1275                         }
1276
1277                         Builder.SetCustomAttribute (new CustomAttributeBuilder (TypeManager.unverifiable_code_ctor, new object [0]));
1278                 }
1279
1280                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder customBuilder)
1281                 {
1282                         if (a.Type == TypeManager.cls_compliant_attribute_type) {
1283                                 if (CodeGen.Assembly.ClsCompliantAttribute == null) {
1284                                         Report.Warning (3012, a.Location, "You must specify the CLSCompliant attribute on the assembly, not the module, to enable CLS compliance checking");
1285                                 }
1286                                 else if (CodeGen.Assembly.IsClsCompliant != a.GetBoolean ()) {
1287                                         Report.SymbolRelatedToPreviousError (CodeGen.Assembly.ClsCompliantAttribute.Location, CodeGen.Assembly.ClsCompliantAttribute.Name);
1288                                         Report.Error (3017, a.Location, "You cannot specify the CLSCompliant attribute on a module that differs from the CLSCompliant attribute on the assembly");
1289                                         return;
1290                                 }
1291                         }
1292
1293                         Builder.SetCustomAttribute (customBuilder);
1294                 }
1295
1296                 /// <summary>
1297                 /// It is called very early therefore can resolve only predefined attributes
1298                 /// </summary>
1299                 public void ResolveAttributes ()
1300                 {
1301                         Attribute a = ResolveAttribute (TypeManager.default_charset_type);
1302                         if (a != null) {
1303                                 DefaultCharSet = a.GetCharSetValue ();
1304                                 switch (DefaultCharSet) {
1305                                         case CharSet.Ansi:
1306                                         case CharSet.None:
1307                                                 break;
1308                                         case CharSet.Auto:
1309                                                 DefaultCharSetType = TypeAttributes.AutoClass;
1310                                                 break;
1311                                         case CharSet.Unicode:
1312                                                 DefaultCharSetType = TypeAttributes.UnicodeClass;
1313                                                 break;
1314                                         default:
1315                                                 Report.Error (1724, a.Location, "Value specified for the argument to 'System.Runtime.InteropServices.DefaultCharSetAttribute' is not valid");
1316                                                 break;
1317                                 }
1318                         }
1319                 }
1320
1321                 public override string[] ValidAttributeTargets {
1322                         get {
1323                                 return attribute_targets;
1324                         }
1325                 }
1326         }
1327 }