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