mcs/class/corlib/System.Reflection.Emit/ILGenerator.cs

   1
   2 //
   3 // System.Reflection.Emit/ILGenerator.cs
   4 //
   5 // Author:
   6 //   Paolo Molaro (lupus@ximian.com)
   7 //
   8 // (C) 2001 Ximian, Inc.  http://www.ximian.com
   9 //
  10
  11 using System;
  12 using System.Collections;
  13 using System.Diagnostics.SymbolStore;
  14 using System.Runtime.InteropServices;
  15 using Mono.CSharp.Debugger;
  16
  17 namespace System.Reflection.Emit {
  18
  19         internal struct ILExceptionBlock {
  20                 public const int CATCH = 0;
  21                 public const int FILTER = 1;
  22                 public const int FINALLY = 2;
  23                 public const int FAULT = 4;
  24
  25                 internal Type extype;
  26                 internal int type;
  27                 internal int start;
  28                 internal int len;
  29                 internal int filter_offset;
  30
  31                 internal void Debug () {
  32 #if NO
  33                         System.Console.Write ("\ttype="+type.ToString()+" start="+start.ToString()+" len="+len.ToString());
  34                         if (extype != null)
  35                                 System.Console.WriteLine (" extype="+extype.ToString());
  36                         else
  37                                 System.Console.WriteLine ("");
  38 #endif
  39                 }
  40         }
  41         internal struct ILExceptionInfo {
  42                 ILExceptionBlock[] handlers;
  43                 internal int start;
  44                 int len;
  45                 internal Label end;
  46
  47                 internal int NumHandlers ()
  48                 {
  49                         return handlers.Length;
  50                 }
  51
  52                 internal void AddCatch (Type extype, int offset)
  53                 {
  54                         int i;
  55                         End (offset);
  56                         add_block (offset);
  57                         i = handlers.Length - 1;
  58                         handlers [i].type = ILExceptionBlock.CATCH;
  59                         handlers [i].start = offset;
  60                         handlers [i].extype = extype;
  61                 }
  62
  63                 internal void AddFinally (int offset)
  64                 {
  65                         int i;
  66                         End (offset);
  67                         add_block (offset);
  68                         i = handlers.Length - 1;
  69                         handlers [i].type = ILExceptionBlock.FINALLY;
  70                         handlers [i].start = offset;
  71                         handlers [i].extype = null;
  72                 }
  73
  74                 internal void End (int offset)
  75                 {
  76                         if (handlers == null)
  77                                 return;
  78                         int i = handlers.Length - 1;
  79                         if (i >= 0)
  80                                 handlers [i].len = offset - handlers [i].start;
  81                 }
  82
  83                 internal int LastClauseType ()
  84                 {
  85                         if (handlers != null)
  86                                 return handlers [handlers.Length-1].type;
  87                         else
  88                                 return ILExceptionBlock.CATCH;
  89                 }
  90
  91                 internal void Debug (int b)
  92                 {
  93 #if NO
  94                         System.Console.WriteLine ("Handler {0} at {1}, len: {2}", b, start, len);
  95                         for (int i = 0; i < handlers.Length; ++i)
  96                                 handlers [i].Debug ();
  97 #endif
  98                 }
  99
 100                 void add_block (int offset)
 101                 {
 102                         if (handlers != null) {
 103                                 int i = handlers.Length;
 104                                 ILExceptionBlock[] new_b = new ILExceptionBlock [i + 1];
 105                                 System.Array.Copy (handlers, new_b, i);
 106                                 handlers = new_b;
 107                                 handlers [i].len = offset - handlers [i].start;
 108                         } else {
 109                                 handlers = new ILExceptionBlock [1];
 110                                 len = offset - start;
 111                         }
 112                 }
 113         }
 114
 115         internal struct ILTokenInfo {
 116                 public MemberInfo member;
 117                 public int code_pos;
 118         }
 119
 120         internal interface TokenGenerator {
 121                 int GetToken (string str);
 122
 123                 int GetToken (MemberInfo member);
 124
 125                 int GetToken (SignatureHelper helper);
 126         }
 127
 128         public class ILGenerator: Object {
 129                 private struct LabelFixup {
 130                         public int offset;    // The number of bytes between pos and the
 131                                                               // offset of the jump
 132                         public int pos;       // Where offset of the label is placed
 133                         public int label_idx; // The label to jump to
 134                 };
 135
 136                 struct LabelData {
 137                         public LabelData (int addr, int maxStack)
 138                         {
 139                                 this.addr = addr;
 140                                 this.maxStack = maxStack;
 141                         }
 142
 143                         public int addr;
 144                         public int maxStack;
 145                 }
 146
 147                 static Type void_type = typeof (void);
 148                 #region Sync with reflection.h
 149                 private byte[] code;
 150                 private int code_len;
 151                 private int max_stack;
 152                 private int cur_stack;
 153                 private LocalBuilder[] locals;
 154                 private ILExceptionInfo[] ex_handlers;
 155                 private int num_token_fixups;
 156                 private ILTokenInfo[] token_fixups;
 157                 #endregion
 158
 159                 private LabelData [] labels;
 160                 private int num_labels;
 161                 private LabelFixup[] fixups;
 162                 private int num_fixups;
 163                 internal Module module;
 164                 internal IMonoSymbolWriter sym_writer;
 165                 private Stack scopes;
 166                 private int cur_block;
 167                 private Stack open_blocks;
 168                 private TokenGenerator token_gen;
 169
 170                 const int defaultFixupSize = 8;
 171                 const int defaultLabelsSize = 8;
 172
 173                 internal ILGenerator (Module m, TokenGenerator token_gen, int size)
 174                 {
 175                         if (size < 0)
 176                                 size = 128;
 177                         code_len = 0;
 178                         code = new byte [size];
 179                         cur_stack = max_stack = 0;
 180                         num_fixups = num_labels = 0;
 181                         token_fixups = new ILTokenInfo [8];
 182                         num_token_fixups = 0;
 183                         module = m;
 184                         if (module is ModuleBuilder)
 185                                 sym_writer = ((ModuleBuilder)module).symbol_writer;
 186                         open_blocks = new Stack ();
 187                         this.token_gen = token_gen;
 188                 }
 189
 190                 private void add_token_fixup (MemberInfo mi)
 191                 {
 192                         if (num_token_fixups == token_fixups.Length) {
 193                                 ILTokenInfo[] ntf = new ILTokenInfo [num_token_fixups * 2];
 194                                 token_fixups.CopyTo (ntf, 0);
 195                                 token_fixups = ntf;
 196                         }
 197                         token_fixups [num_token_fixups].member = mi;
 198                         token_fixups [num_token_fixups++].code_pos = code_len;
 199                 }
 200
 201                 private void make_room (int nbytes)
 202                 {
 203                         if (code_len + nbytes < code.Length)
 204                                 return;
 205                         byte[] new_code = new byte [(code_len + nbytes) * 2 + 128];
 206                         System.Array.Copy (code, 0, new_code, 0, code.Length);
 207                         code = new_code;
 208                 }
 209
 210                 private void emit_int (int val)
 211                 {
 212                         code [code_len++] = (byte) (val & 0xFF);
 213                         code [code_len++] = (byte) ((val >> 8) & 0xFF);
 214                         code [code_len++] = (byte) ((val >> 16) & 0xFF);
 215                         code [code_len++] = (byte) ((val >> 24) & 0xFF);
 216                 }
 217
 218                 /* change to pass by ref to avoid copy */
 219                 private void ll_emit (OpCode opcode)
 220                 {
 221                         /*
 222                          * there is already enough room allocated in code.
 223                          */
 224                         // access op1 and op2 directly since the Value property is useless
 225                         if (opcode.Size == 2)
 226                                 code [code_len++] = opcode.op1;
 227                         code [code_len++] = opcode.op2;
 228                         /*
 229                          * We should probably keep track of stack needs here.
 230                          * Or we may want to run the verifier on the code before saving it
 231                          * (this may be needed anyway when the ILGenerator is not used...).
 232                          */
 233                         switch (opcode.StackBehaviourPush) {
 234                         case StackBehaviour.Push1:
 235                         case StackBehaviour.Pushi:
 236                         case StackBehaviour.Pushi8:
 237                         case StackBehaviour.Pushr4:
 238                         case StackBehaviour.Pushr8:
 239                         case StackBehaviour.Pushref:
 240                         case StackBehaviour.Varpush: /* again we are conservative and assume it pushes 1 */
 241                                 cur_stack ++;
 242                                 break;
 243                         case StackBehaviour.Push1_push1:
 244                                 cur_stack += 2;
 245                                 break;
 246                         }
 247                         if (max_stack < cur_stack)
 248                                 max_stack = cur_stack;
 249
 250                         /*
 251                          * Note that we adjust for the pop behaviour _after_ setting max_stack.
 252                          */
 253                         switch (opcode.StackBehaviourPop) {
 254                         case StackBehaviour.Varpop:
 255                                 break; /* we are conservative and assume it doesn't decrease the stack needs */
 256                         case StackBehaviour.Pop1:
 257                         case StackBehaviour.Popi:
 258                         case StackBehaviour.Popref:
 259                                 cur_stack --;
 260                                 break;
 261                         case StackBehaviour.Pop1_pop1:
 262                         case StackBehaviour.Popi_pop1:
 263                         case StackBehaviour.Popi_popi:
 264                         case StackBehaviour.Popi_popi8:
 265                         case StackBehaviour.Popi_popr4:
 266                         case StackBehaviour.Popi_popr8:
 267                         case StackBehaviour.Popref_pop1:
 268                         case StackBehaviour.Popref_popi:
 269                                 cur_stack -= 2;
 270                                 break;
 271                         case StackBehaviour.Popi_popi_popi:
 272                         case StackBehaviour.Popref_popi_popi:
 273                         case StackBehaviour.Popref_popi_popi8:
 274                         case StackBehaviour.Popref_popi_popr4:
 275                         case StackBehaviour.Popref_popi_popr8:
 276                         case StackBehaviour.Popref_popi_popref:
 277                                 cur_stack -= 3;
 278                                 break;
 279                         }
 280                 }
 281
 282                 private static int target_len (OpCode opcode)
 283                 {
 284                         if (opcode.OperandType == OperandType.InlineBrTarget)
 285                                 return 4;
 286                         return 1;
 287                 }
 288
 289                 private void InternalEndClause ()
 290                 {
 291                         switch (ex_handlers [cur_block].LastClauseType ()) {
 292                         case ILExceptionBlock.CATCH:
 293                                 // how could we optimize code size here?
 294                                 Emit (OpCodes.Leave, ex_handlers [cur_block].end);
 295                                 break;
 296                         case ILExceptionBlock.FAULT:
 297                         case ILExceptionBlock.FINALLY:
 298                                 Emit (OpCodes.Endfinally);
 299                                 break;
 300                         case ILExceptionBlock.FILTER:
 301                                 Emit (OpCodes.Endfilter);
 302                                 break;
 303                         }
 304                 }
 305
 306                 public virtual void BeginCatchBlock (Type exceptionType)
 307                 {
 308                         if (open_blocks.Count <= 0)
 309                                 throw new NotSupportedException ("Not in an exception block");
 310                         InternalEndClause ();
 311                         ex_handlers [cur_block].AddCatch (exceptionType, code_len);
 312                         cur_stack = 1; // the exception object is on the stack by default
 313                         if (max_stack < cur_stack)
 314                                 max_stack = cur_stack;
 315                         //System.Console.WriteLine ("Begin catch Block: {0} {1}",exceptionType.ToString(), max_stack);
 316                         //throw new NotImplementedException ();
 317                 }
 318
 319                 [MonoTODO]
 320                 public virtual void BeginExceptFilterBlock ()
 321                 {
 322                         throw new NotImplementedException ();
 323                 }
 324
 325                 public virtual Label BeginExceptionBlock ()
 326                 {
 327                         //System.Console.WriteLine ("Begin Block");
 328
 329                         if (ex_handlers != null) {
 330                                 cur_block = ex_handlers.Length;
 331                                 ILExceptionInfo[] new_ex = new ILExceptionInfo [cur_block + 1];
 332                                 System.Array.Copy (ex_handlers, new_ex, cur_block);
 333                                 ex_handlers = new_ex;
 334                         } else {
 335                                 ex_handlers = new ILExceptionInfo [1];
 336                                 cur_block = 0;
 337                         }
 338                         open_blocks.Push (cur_block);
 339                         ex_handlers [cur_block].start = code_len;
 340                         return ex_handlers [cur_block].end = DefineLabel ();
 341                 }
 342
 343                 public virtual void BeginFaultBlock()
 344                 {
 345                         if (open_blocks.Count <= 0)
 346                                 throw new NotSupportedException ("Not in an exception block");
 347                         //System.Console.WriteLine ("Begin fault Block");
 348                         //throw new NotImplementedException ();
 349                 }
 350
 351                 public virtual void BeginFinallyBlock()
 352                 {
 353                         if (open_blocks.Count <= 0)
 354                                 throw new NotSupportedException ("Not in an exception block");
 355                         InternalEndClause ();
 356                         //System.Console.WriteLine ("Begin finally Block");
 357                         ex_handlers [cur_block].AddFinally (code_len);
 358                 }
 359
 360                 public virtual void BeginScope ()
 361                 {
 362                         if (sym_writer != null) {
 363                                 if (scopes == null)
 364                                         scopes = new Stack ();
 365                                 scopes.Push (sym_writer.OpenScope (code_len));
 366                         }
 367                 }
 368
 369                 public LocalBuilder DeclareLocal (Type localType)
 370                 {
 371                         LocalBuilder res = new LocalBuilder (localType, this);
 372                         if (locals != null) {
 373                                 LocalBuilder[] new_l = new LocalBuilder [locals.Length + 1];
 374                                 System.Array.Copy (locals, new_l, locals.Length);
 375                                 new_l [locals.Length] = res;
 376                                 locals = new_l;
 377                         } else {
 378                                 locals = new LocalBuilder [1];
 379                                 locals [0] = res;
 380                         }
 381                         res.position = (uint)(locals.Length - 1);
 382                         return res;
 383                 }
 384
 385                 public virtual Label DefineLabel ()
 386                 {
 387                         if (labels == null)
 388                                 labels = new LabelData [defaultLabelsSize];
 389                         else if (num_labels >= labels.Length) {
 390                                 LabelData [] t = new LabelData [labels.Length * 2];
 391                                 Array.Copy (labels, t, labels.Length);
 392                                 labels = t;
 393                         }
 394
 395                         labels [num_labels] = new LabelData (-1, 0);
 396
 397                         return new Label (num_labels++);
 398                 }
 399
 400                 public virtual void Emit (OpCode opcode)
 401                 {
 402                         make_room (2);
 403                         ll_emit (opcode);
 404                 }
 405
 406                 public virtual void Emit (OpCode opcode, Byte val)
 407                 {
 408                         make_room (3);
 409                         ll_emit (opcode);
 410                         code [code_len++] = val;
 411                 }
 412
 413                 public virtual void Emit (OpCode opcode, ConstructorInfo constructor)
 414                 {
 415                         int token = token_gen.GetToken (constructor);
 416                         make_room (6);
 417                         ll_emit (opcode);
 418                         if (constructor.DeclaringType.Module == module)
 419                                 add_token_fixup (constructor);
 420                         emit_int (token);
 421
 422                         if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
 423                                 cur_stack -= constructor.GetParameterCount ();
 424                 }
 425
 426                 public virtual void Emit (OpCode opcode, double val)
 427                 {
 428                         Double.AssertEndianity (out val);
 429
 430                         byte[] s = System.BitConverter.GetBytes (val);
 431                         make_room (10);
 432                         ll_emit (opcode);
 433                         if (BitConverter.IsLittleEndian){
 434                                 System.Array.Copy (s, 0, code, code_len, 8);
 435                                 code_len += 8;
 436                         } else {
 437                                 code [code_len++] = s [7];
 438                                 code [code_len++] = s [6];
 439                                 code [code_len++] = s [5];
 440                                 code [code_len++] = s [4];
 441                                 code [code_len++] = s [3];
 442                                 code [code_len++] = s [2];
 443                                 code [code_len++] = s [1];
 444                                 code [code_len++] = s [0];
 445                         }
 446                 }
 447
 448                 public virtual void Emit (OpCode opcode, FieldInfo field)
 449                 {
 450                         int token = token_gen.GetToken (field);
 451                         make_room (6);
 452                         ll_emit (opcode);
 453                         if (field.DeclaringType.Module == module)
 454                                 add_token_fixup (field);
 455                         emit_int (token);
 456                 }
 457
 458                 public virtual void Emit (OpCode opcode, Int16 val)
 459                 {
 460                         make_room (4);
 461                         ll_emit (opcode);
 462                         code [code_len++] = (byte) (val & 0xFF);
 463                         code [code_len++] = (byte) ((val >> 8) & 0xFF);
 464                 }
 465
 466                 public virtual void Emit (OpCode opcode, int val)
 467                 {
 468                         make_room (6);
 469                         ll_emit (opcode);
 470                         emit_int (val);
 471                 }
 472
 473                 public virtual void Emit (OpCode opcode, long val)
 474                 {
 475                         make_room (10);
 476                         ll_emit (opcode);
 477                         code [code_len++] = (byte) (val & 0xFF);
 478                         code [code_len++] = (byte) ((val >> 8) & 0xFF);
 479                         code [code_len++] = (byte) ((val >> 16) & 0xFF);
 480                         code [code_len++] = (byte) ((val >> 24) & 0xFF);
 481                         code [code_len++] = (byte) ((val >> 32) & 0xFF);
 482                         code [code_len++] = (byte) ((val >> 40) & 0xFF);
 483                         code [code_len++] = (byte) ((val >> 48) & 0xFF);
 484                         code [code_len++] = (byte) ((val >> 56) & 0xFF);
 485                 }
 486
 487                 public virtual void Emit (OpCode opcode, Label label)
 488                 {
 489                         int tlen = target_len (opcode);
 490                         make_room (6);
 491                         ll_emit (opcode);
 492                         if (cur_stack > labels [label.label].maxStack)
 493                                 labels [label.label].maxStack = cur_stack;
 494
 495                         if (fixups == null)
 496                                 fixups = new LabelFixup [defaultFixupSize];
 497                         else if (num_fixups >= fixups.Length) {
 498                                 LabelFixup[] newf = new LabelFixup [fixups.Length + 16];
 499                                 System.Array.Copy (fixups, newf, fixups.Length);
 500                                 fixups = newf;
 501                         }
 502                         fixups [num_fixups].offset = tlen;
 503                         fixups [num_fixups].pos = code_len;
 504                         fixups [num_fixups].label_idx = label.label;
 505                         num_fixups++;
 506                         code_len += tlen;
 507
 508                 }
 509
 510                 public virtual void Emit (OpCode opcode, Label[] labels)
 511                 {
 512                         /* opcode needs to be switch. */
 513                         int count = labels.Length;
 514                         make_room (6 + count * 4);
 515                         ll_emit (opcode);
 516
 517                         for (int i = 0; i < count; ++i)
 518                                 if (cur_stack > this.labels [labels [i].label].maxStack)
 519                                         this.labels [labels [i].label].maxStack = cur_stack;
 520
 521                         emit_int (count);
 522                         if (fixups == null)
 523                                 fixups = new LabelFixup [defaultFixupSize + count];
 524                         else if (num_fixups + count >= fixups.Length) {
 525                                 LabelFixup[] newf = new LabelFixup [fixups.Length + count + 16];
 526                                 System.Array.Copy (fixups, newf, fixups.Length);
 527                                 fixups = newf;
 528                         }
 529
 530                         // ECMA 335, Partition III, p94 (7-10)
 531                         //
 532                         // The switch instruction implements a jump table. The format of
 533                         // the instruction is an unsigned int32 representing the number of targets N,
 534                         // followed by N int32 values specifying jump targets: these targets are
 535                         // represented as offsets (positive or negative) from the beginning of the
 536                         // instruction following this switch instruction.
 537                         //
 538                         // We must make sure it gets an offset from the *end* of the last label
 539                         // (eg, the beginning of the instruction following this).
 540                         //
 541                         // remaining is the number of bytes from the current instruction to the
 542                         // instruction that will be emitted.
 543
 544                         for (int i = 0, remaining = count * 4; i < count; ++i, remaining -= 4) {
 545                                 fixups [num_fixups].offset = remaining;
 546                                 fixups [num_fixups].pos = code_len;
 547                                 fixups [num_fixups].label_idx = labels [i].label;
 548                                 num_fixups++;
 549                                 code_len += 4;
 550                         }
 551                 }
 552
 553                 public virtual void Emit (OpCode opcode, LocalBuilder lbuilder)
 554                 {
 555                         uint pos = lbuilder.position;
 556                         bool load_addr = false;
 557                         bool is_store = false;
 558                         make_room (6);
 559
 560                         if (lbuilder.ilgen != this)
 561                                 throw new Exception ("Trying to emit a local from a different ILGenerator.");
 562
 563                         /* inline the code from ll_emit () to optimize il code size */
 564                         if (opcode.StackBehaviourPop == StackBehaviour.Pop1) {
 565                                 cur_stack --;
 566                                 is_store = true;
 567                         } else {
 568                                 cur_stack++;
 569                                 if (cur_stack > max_stack)
 570                                         max_stack = cur_stack;
 571                                 load_addr = opcode.StackBehaviourPush == StackBehaviour.Pushi;
 572                         }
 573                         if (load_addr) {
 574                                 if (pos < 256) {
 575                                         code [code_len++] = (byte)0x12;
 576                                         code [code_len++] = (byte)pos;
 577                                 } else {
 578                                         code [code_len++] = (byte)0xfe;
 579                                         code [code_len++] = (byte)0x0d;
 580                                         code [code_len++] = (byte)(pos & 0xff);
 581                                         code [code_len++] = (byte)((pos >> 8) & 0xff);
 582                                 }
 583                         } else {
 584                                 if (is_store) {
 585                                         if (pos < 4) {
 586                                                 code [code_len++] = (byte)(0x0a + pos);
 587                                         } else if (pos < 256) {
 588                                                 code [code_len++] = (byte)0x13;
 589                                                 code [code_len++] = (byte)pos;
 590                                         } else {
 591                                                 code [code_len++] = (byte)0xfe;
 592                                                 code [code_len++] = (byte)0x0e;
 593                                                 code [code_len++] = (byte)(pos & 0xff);
 594                                                 code [code_len++] = (byte)((pos >> 8) & 0xff);
 595                                         }
 596                                 } else {
 597                                         if (pos < 4) {
 598                                                 code [code_len++] = (byte)(0x06 + pos);
 599                                         } else if (pos < 256) {
 600                                                 code [code_len++] = (byte)0x11;
 601                                                 code [code_len++] = (byte)pos;
 602                                         } else {
 603                                                 code [code_len++] = (byte)0xfe;
 604                                                 code [code_len++] = (byte)0x0c;
 605                                                 code [code_len++] = (byte)(pos & 0xff);
 606                                                 code [code_len++] = (byte)((pos >> 8) & 0xff);
 607                                         }
 608                                 }
 609                         }
 610                 }
 611
 612                 public virtual void Emit (OpCode opcode, MethodInfo method)
 613                 {
 614                         if (method == null)
 615                                 throw new ArgumentNullException ("method");
 616
 617                         int token = token_gen.GetToken (method);
 618                         make_room (6);
 619                         ll_emit (opcode);
 620                         if (method.DeclaringType.Module == module)
 621                                 add_token_fixup (method);
 622                         emit_int (token);
 623                         if (method.ReturnType != void_type)
 624                                 cur_stack ++;
 625
 626                         if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
 627                                 cur_stack -= method.GetParameterCount ();
 628                 }
 629
 630                 [CLSCompliant(false)]
 631                 public void Emit (OpCode opcode, sbyte val)
 632                 {
 633                         make_room (3);
 634                         ll_emit (opcode);
 635                         code [code_len++] = (byte)val;
 636                 }
 637
 638                 public virtual void Emit (OpCode opcode, SignatureHelper shelper)
 639                 {
 640                         int token = token_gen.GetToken (shelper);
 641                         make_room (6);
 642                         ll_emit (opcode);
 643                         emit_int (token);
 644                 }
 645
 646                 public virtual void Emit (OpCode opcode, float val)
 647                 {
 648                         byte[] s = System.BitConverter.GetBytes (val);
 649                         make_room (6);
 650                         ll_emit (opcode);
 651                         if (BitConverter.IsLittleEndian){
 652                                 System.Array.Copy (s, 0, code, code_len, 4);
 653                                 code_len += 4;
 654                         } else {
 655                                 code [code_len++] = s [3];
 656                                 code [code_len++] = s [2];
 657                                 code [code_len++] = s [1];
 658                                 code [code_len++] = s [0];
 659                         }
 660                 }
 661
 662                 public virtual void Emit (OpCode opcode, string val)
 663                 {
 664                         int token = token_gen.GetToken (val);
 665                         make_room (6);
 666                         ll_emit (opcode);
 667                         emit_int (token);
 668                 }
 669
 670                 public virtual void Emit (OpCode opcode, Type type)
 671                 {
 672                         make_room (6);
 673                         ll_emit (opcode);
 674                         emit_int (token_gen.GetToken (type));
 675                 }
 676
 677                 [MonoTODO ("Do something about varargs method")]
 678                 public void EmitCall (OpCode opcode, MethodInfo methodinfo, Type[] optionalParamTypes)
 679                 {
 680                         if (methodinfo == null)
 681                                 throw new ArgumentNullException ("methodinfo can not be null");
 682                         short value = opcode.Value;
 683                         if (!(value == OpCodes.Call.Value || value == OpCodes.Callvirt.Value))
 684                                 throw new NotSupportedException ("Only Call and CallVirt are allowed");
 685                         if (optionalParamTypes != null){
 686                                 if ((methodinfo.CallingConvention & CallingConventions.VarArgs)  == 0){
 687                                         throw new InvalidOperationException ("Method is not VarArgs method and optional types were passed");
 688                                 }
 689                         }
 690                         Emit (opcode, methodinfo);
 691                 }
 692
 693                 public void EmitCalli (OpCode opcode, CallingConvention unmanagedCallConv, Type returnType, Type[] paramTypes)
 694                 {
 695                         SignatureHelper helper
 696                                 = SignatureHelper.GetMethodSigHelper (module, 0, unmanagedCallConv, returnType, paramTypes);
 697                         Emit (opcode, helper);
 698                 }
 699
 700                 public void EmitCalli (OpCode opcode, CallingConventions callConv, Type returnType, Type[] paramTypes, Type[] optionalParamTypes)
 701                 {
 702                         if (optionalParamTypes != null)
 703                                 throw new NotImplementedException ();
 704
 705                         SignatureHelper helper
 706                                 = SignatureHelper.GetMethodSigHelper (module, callConv, 0, returnType, paramTypes);
 707                         Emit (opcode, helper);
 708                 }
 709
 710                 public virtual void EmitWriteLine (FieldInfo field)
 711                 {
 712                         if (field == null)
 713                                 throw new ArgumentNullException ("field");
 714
 715                         // The MS implementation does not check for valuetypes here but it
 716                         // should. Also, it should check that if the field is not static,
 717                         // then it is a member of this type.
 718                         if (field.IsStatic)
 719                                 Emit (OpCodes.Ldsfld, field);
 720                         else {
 721                                 Emit (OpCodes.Ldarg_0);
 722                                 Emit (OpCodes.Ldfld, field);
 723                         }
 724                         Emit (OpCodes.Call,
 725                               typeof (Console).GetMethod ("WriteLine",
 726                                                           new Type[1] { field.FieldType }));
 727                 }
 728
 729                 public virtual void EmitWriteLine (LocalBuilder lbuilder)
 730                 {
 731                         if (lbuilder == null)
 732                                 throw new ArgumentNullException ("lbuilder");
 733                         if (lbuilder.LocalType is TypeBuilder)
 734                                 throw new  ArgumentException ("Output streams do not support TypeBuilders.");
 735                         // The MS implementation does not check for valuetypes here but it
 736                         // should.
 737                         Emit (OpCodes.Ldloc, lbuilder);
 738                         Emit (OpCodes.Call,
 739                               typeof (Console).GetMethod ("WriteLine",
 740                                                           new Type[1] { lbuilder.LocalType }));
 741                 }
 742
 743                 public virtual void EmitWriteLine (string val)
 744                 {
 745                         Emit (OpCodes.Ldstr, val);
 746                         Emit (OpCodes.Call,
 747                               typeof (Console).GetMethod ("WriteLine",
 748                                                           new Type[1] { typeof(string)}));
 749                 }
 750
 751                 public virtual void EndExceptionBlock ()
 752                 {
 753                         if (open_blocks.Count <= 0)
 754                                 throw new NotSupportedException ("Not in an exception block");
 755                         InternalEndClause ();
 756                         MarkLabel (ex_handlers [cur_block].end);
 757                         ex_handlers [cur_block].End (code_len);
 758                         ex_handlers [cur_block].Debug (cur_block);
 759                         //System.Console.WriteLine ("End Block {0} (handlers: {1})", cur_block, ex_handlers [cur_block].NumHandlers ());
 760                         open_blocks.Pop ();
 761                         if (open_blocks.Count > 0)
 762                                 cur_block = (int)open_blocks.Peek ();
 763                         //Console.WriteLine ("curblock restored to {0}", cur_block);
 764                         //throw new NotImplementedException ();
 765                 }
 766
 767                 public virtual void EndScope ()
 768                 {
 769                         if (sym_writer != null) {
 770                                 sym_writer.CloseScope (code_len);
 771                                 if (scopes == null)
 772                                         throw new InvalidOperationException ();
 773                                 scopes.Pop ();
 774                         }
 775                 }
 776
 777                 public virtual void MarkLabel (Label loc)
 778                 {
 779                         if (loc.label < 0 || loc.label >= num_labels)
 780                                 throw new System.ArgumentException ("The label is not valid");
 781                         if (labels [loc.label].addr >= 0)
 782                                 throw new System.ArgumentException ("The label was already defined");
 783                         labels [loc.label].addr = code_len;
 784                         if (labels [loc.label].maxStack > cur_stack)
 785                                 cur_stack = labels [loc.label].maxStack;
 786                 }
 787
 788                 public virtual void MarkSequencePoint (ISymbolDocumentWriter document, int startLine,
 789                                                        int startColumn, int endLine, int endColumn)
 790                 {
 791                         if (sym_writer == null)
 792                                 return;
 793
 794                         sym_writer.MarkSequencePoint (code_len, startLine, startColumn);
 795                 }
 796
 797                 public virtual void ThrowException (Type exceptionType)
 798                 {
 799                         if (exceptionType == null)
 800                                 throw new ArgumentNullException ("exceptionType");
 801                         if (! ((exceptionType == typeof (Exception)) ||
 802                                    exceptionType.IsSubclassOf (typeof (Exception))))
 803                                 throw new ArgumentException ("Type should be an exception type", "exceptionType");
 804                         ConstructorInfo ctor = exceptionType.GetConstructor (new Type[0]);
 805                         if (ctor == null)
 806                                 throw new ArgumentException ("Type should have a default constructor", "exceptionType");
 807                         Emit (OpCodes.Newobj, ctor);
 808                         Emit (OpCodes.Throw);
 809                 }
 810
 811                 [MonoTODO]
 812                 public void UsingNamespace (String usingNamespace)
 813                 {
 814                         throw new NotImplementedException ();
 815                 }
 816
 817                 internal void label_fixup ()
 818                 {
 819                         for (int i = 0; i < num_fixups; ++i) {
 820
 821                                 // Diff is the offset from the end of the jump instruction to the address of the label
 822                                 int diff = labels [fixups [i].label_idx].addr - (fixups [i].pos + fixups [i].offset);
 823                                 if (fixups [i].offset == 1) {
 824                                         code [fixups [i].pos] = (byte)((sbyte) diff);
 825                                 } else {
 826                                         int old_cl = code_len;
 827                                         code_len = fixups [i].pos;
 828                                         emit_int (diff);
 829                                         code_len = old_cl;
 830                                 }
 831                         }
 832                 }
 833         }
 834 }