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

   1
   2 //
   3 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining
   6 // a copy of this software and associated documentation files (the
   7 // "Software"), to deal in the Software without restriction, including
   8 // without limitation the rights to use, copy, modify, merge, publish,
   9 // distribute, sublicense, and/or sell copies of the Software, and to
  10 // permit persons to whom the Software is furnished to do so, subject to
  11 // the following conditions:
  12 //
  13 // The above copyright notice and this permission notice shall be
  14 // included in all copies or substantial portions of the Software.
  15 //
  16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  17 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  18 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  19 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  20 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  21 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  22 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23 //
  24
  25 //
  26 // System.Reflection.Emit/ILGenerator.cs
  27 //
  28 // Author:
  29 //   Paolo Molaro (lupus@ximian.com)
  30 //
  31 // (C) 2001 Ximian, Inc.  http://www.ximian.com
  32 //
  33
  34 using System;
  35 using System.Collections;
  36 using System.Diagnostics.SymbolStore;
  37 using System.Runtime.InteropServices;
  38
  39 namespace System.Reflection.Emit {
  40
  41         internal struct ILExceptionBlock {
  42                 public const int CATCH = 0;
  43                 public const int FILTER = 1;
  44                 public const int FINALLY = 2;
  45                 public const int FAULT = 4;
  46                 public const int FILTER_START = -1;
  47
  48                 internal Type extype;
  49                 internal int type;
  50                 internal int start;
  51                 internal int len;
  52                 internal int filter_offset;
  53
  54                 internal void Debug () {
  55 #if NO
  56                         System.Console.Write ("\ttype="+type.ToString()+" start="+start.ToString()+" len="+len.ToString());
  57                         if (extype != null)
  58                                 System.Console.WriteLine (" extype="+extype.ToString());
  59                         else
  60                                 System.Console.WriteLine (String.Empty);
  61 #endif
  62                 }
  63         }
  64         internal struct ILExceptionInfo {
  65 #pragma warning disable 169
  66 #pragma warning disable 414
  67                 ILExceptionBlock[] handlers;
  68                 internal int start;
  69                 int len;
  70                 internal Label end;
  71 #pragma warning restore 169
  72 #pragma warning restore 414
  73
  74                 internal int NumHandlers ()
  75                 {
  76                         return handlers.Length;
  77                 }
  78
  79                 internal void AddCatch (Type extype, int offset)
  80                 {
  81                         int i;
  82                         End (offset);
  83                         add_block (offset);
  84                         i = handlers.Length - 1;
  85                         handlers [i].type = ILExceptionBlock.CATCH;
  86                         handlers [i].start = offset;
  87                         handlers [i].extype = extype;
  88                 }
  89
  90                 internal void AddFinally (int offset)
  91                 {
  92                         int i;
  93                         End (offset);
  94                         add_block (offset);
  95                         i = handlers.Length - 1;
  96                         handlers [i].type = ILExceptionBlock.FINALLY;
  97                         handlers [i].start = offset;
  98                         handlers [i].extype = null;
  99                 }
 100
 101                 internal void AddFault (int offset)
 102                 {
 103                         int i;
 104                         End (offset);
 105                         add_block (offset);
 106                         i = handlers.Length - 1;
 107                         handlers [i].type = ILExceptionBlock.FAULT;
 108                         handlers [i].start = offset;
 109                         handlers [i].extype = null;
 110                 }
 111
 112                 internal void AddFilter (int offset)
 113                 {
 114                         int i;
 115                         End (offset);
 116                         add_block (offset);
 117                         i = handlers.Length - 1;
 118                         handlers [i].type = ILExceptionBlock.FILTER_START;
 119                         handlers [i].extype = null;
 120                         handlers [i].filter_offset = offset;
 121                 }
 122
 123                 internal void End (int offset)
 124                 {
 125                         if (handlers == null)
 126                                 return;
 127                         int i = handlers.Length - 1;
 128                         if (i >= 0)
 129                                 handlers [i].len = offset - handlers [i].start;
 130                 }
 131
 132                 internal int LastClauseType ()
 133                 {
 134                         if (handlers != null)
 135                                 return handlers [handlers.Length-1].type;
 136                         else
 137                                 return ILExceptionBlock.CATCH;
 138                 }
 139
 140                 internal void PatchFilterClause (int start)
 141                 {
 142                         if (handlers != null && handlers.Length > 0) {
 143                                 handlers [handlers.Length - 1].start = start;
 144                                 handlers [handlers.Length - 1].type = ILExceptionBlock.FILTER;
 145                         }
 146                 }
 147
 148                 internal void Debug (int b)
 149                 {
 150 #if NO
 151                         System.Console.WriteLine ("Handler {0} at {1}, len: {2}", b, start, len);
 152                         for (int i = 0; i < handlers.Length; ++i)
 153                                 handlers [i].Debug ();
 154 #endif
 155                 }
 156
 157                 void add_block (int offset)
 158                 {
 159                         if (handlers != null) {
 160                                 int i = handlers.Length;
 161                                 ILExceptionBlock[] new_b = new ILExceptionBlock [i + 1];
 162                                 System.Array.Copy (handlers, new_b, i);
 163                                 handlers = new_b;
 164                                 handlers [i].len = offset - handlers [i].start;
 165                         } else {
 166                                 handlers = new ILExceptionBlock [1];
 167                                 len = offset - start;
 168                         }
 169                 }
 170         }
 171
 172         internal struct ILTokenInfo {
 173                 public MemberInfo member;
 174                 public int code_pos;
 175         }
 176
 177         internal interface TokenGenerator {
 178                 int GetToken (string str);
 179
 180                 int GetToken (MemberInfo member);
 181
 182                 int GetToken (MethodInfo method, Type[] opt_param_types);
 183
 184                 int GetToken (SignatureHelper helper);
 185         }
 186
 187         [ComVisible (true)]
 188         [ComDefaultInterface (typeof (_ILGenerator))]
 189         [ClassInterface (ClassInterfaceType.None)]
 190         public class ILGenerator: _ILGenerator {
 191                 private struct LabelFixup {
 192                         public int offset;    // The number of bytes between pos and the
 193                                                               // offset of the jump
 194                         public int pos;       // Where offset of the label is placed
 195                         public int label_idx; // The label to jump to
 196                 };
 197
 198                 struct LabelData {
 199                         public LabelData (int addr, int maxStack)
 200                         {
 201                                 this.addr = addr;
 202                                 this.maxStack = maxStack;
 203                         }
 204
 205                         public int addr;
 206                         public int maxStack;
 207                 }
 208
 209                 static readonly Type void_type = typeof (void);
 210                 #region Sync with reflection.h
 211                 private byte[] code;
 212                 private int code_len;
 213                 private int max_stack;
 214                 private int cur_stack;
 215                 private LocalBuilder[] locals;
 216                 private ILExceptionInfo[] ex_handlers;
 217                 private int num_token_fixups;
 218                 private ILTokenInfo[] token_fixups;
 219                 #endregion
 220
 221                 private LabelData [] labels;
 222                 private int num_labels;
 223                 private LabelFixup[] fixups;
 224                 private int num_fixups;
 225                 internal Module module;
 226                 private int cur_block;
 227                 private Stack open_blocks;
 228                 private TokenGenerator token_gen;
 229
 230                 const int defaultFixupSize = 4;
 231                 const int defaultLabelsSize = 4;
 232                 const int defaultExceptionStackSize = 2;
 233
 234                 ArrayList sequencePointLists;
 235                 SequencePointList currentSequence;
 236
 237                 internal ILGenerator (Module m, TokenGenerator token_gen, int size)
 238                 {
 239                         if (size < 0)
 240                                 size = 128;
 241                         code = new byte [size];
 242                         token_fixups = new ILTokenInfo [8];
 243                         module = m;
 244                         this.token_gen = token_gen;
 245                 }
 246
 247                 private void add_token_fixup (MemberInfo mi)
 248                 {
 249                         if (num_token_fixups == token_fixups.Length) {
 250                                 ILTokenInfo[] ntf = new ILTokenInfo [num_token_fixups * 2];
 251                                 token_fixups.CopyTo (ntf, 0);
 252                                 token_fixups = ntf;
 253                         }
 254                         token_fixups [num_token_fixups].member = mi;
 255                         token_fixups [num_token_fixups++].code_pos = code_len;
 256                 }
 257
 258                 private void make_room (int nbytes)
 259                 {
 260                         if (code_len + nbytes < code.Length)
 261                                 return;
 262                         byte[] new_code = new byte [(code_len + nbytes) * 2 + 128];
 263                         System.Array.Copy (code, 0, new_code, 0, code.Length);
 264                         code = new_code;
 265                 }
 266
 267                 private void emit_int (int val)
 268                 {
 269                         code [code_len++] = (byte) (val & 0xFF);
 270                         code [code_len++] = (byte) ((val >> 8) & 0xFF);
 271                         code [code_len++] = (byte) ((val >> 16) & 0xFF);
 272                         code [code_len++] = (byte) ((val >> 24) & 0xFF);
 273                 }
 274
 275                 /* change to pass by ref to avoid copy */
 276                 private void ll_emit (OpCode opcode)
 277                 {
 278                         /*
 279                          * there is already enough room allocated in code.
 280                          */
 281                         // access op1 and op2 directly since the Value property is useless
 282                         if (opcode.Size == 2)
 283                                 code [code_len++] = opcode.op1;
 284                         code [code_len++] = opcode.op2;
 285                         /*
 286                          * We should probably keep track of stack needs here.
 287                          * Or we may want to run the verifier on the code before saving it
 288                          * (this may be needed anyway when the ILGenerator is not used...).
 289                          */
 290                         switch (opcode.StackBehaviourPush) {
 291                         case StackBehaviour.Push1:
 292                         case StackBehaviour.Pushi:
 293                         case StackBehaviour.Pushi8:
 294                         case StackBehaviour.Pushr4:
 295                         case StackBehaviour.Pushr8:
 296                         case StackBehaviour.Pushref:
 297                         case StackBehaviour.Varpush: /* again we are conservative and assume it pushes 1 */
 298                                 cur_stack ++;
 299                                 break;
 300                         case StackBehaviour.Push1_push1:
 301                                 cur_stack += 2;
 302                                 break;
 303                         }
 304                         if (max_stack < cur_stack)
 305                                 max_stack = cur_stack;
 306
 307                         /*
 308                          * Note that we adjust for the pop behaviour _after_ setting max_stack.
 309                          */
 310                         switch (opcode.StackBehaviourPop) {
 311                         case StackBehaviour.Varpop:
 312                                 break; /* we are conservative and assume it doesn't decrease the stack needs */
 313                         case StackBehaviour.Pop1:
 314                         case StackBehaviour.Popi:
 315                         case StackBehaviour.Popref:
 316                                 cur_stack --;
 317                                 break;
 318                         case StackBehaviour.Pop1_pop1:
 319                         case StackBehaviour.Popi_pop1:
 320                         case StackBehaviour.Popi_popi:
 321                         case StackBehaviour.Popi_popi8:
 322                         case StackBehaviour.Popi_popr4:
 323                         case StackBehaviour.Popi_popr8:
 324                         case StackBehaviour.Popref_pop1:
 325                         case StackBehaviour.Popref_popi:
 326                                 cur_stack -= 2;
 327                                 break;
 328                         case StackBehaviour.Popi_popi_popi:
 329                         case StackBehaviour.Popref_popi_popi:
 330                         case StackBehaviour.Popref_popi_popi8:
 331                         case StackBehaviour.Popref_popi_popr4:
 332                         case StackBehaviour.Popref_popi_popr8:
 333                         case StackBehaviour.Popref_popi_popref:
 334                                 cur_stack -= 3;
 335                                 break;
 336                         }
 337                 }
 338
 339                 private static int target_len (OpCode opcode)
 340                 {
 341                         if (opcode.OperandType == OperandType.InlineBrTarget)
 342                                 return 4;
 343                         return 1;
 344                 }
 345
 346                 private void InternalEndClause ()
 347                 {
 348                         switch (ex_handlers [cur_block].LastClauseType ()) {
 349                         case ILExceptionBlock.CATCH:
 350                         case ILExceptionBlock.FILTER:
 351                         case ILExceptionBlock.FILTER_START:
 352                                 // how could we optimize code size here?
 353                                 Emit (OpCodes.Leave, ex_handlers [cur_block].end);
 354                                 break;
 355                         case ILExceptionBlock.FAULT:
 356                         case ILExceptionBlock.FINALLY:
 357                                 Emit (OpCodes.Endfinally);
 358                                 break;
 359                         }
 360                 }
 361
 362                 public virtual void BeginCatchBlock (Type exceptionType)
 363                 {
 364                         if (open_blocks == null)
 365                                 open_blocks = new Stack (defaultExceptionStackSize);
 366
 367                         if (open_blocks.Count <= 0)
 368                                 throw new NotSupportedException ("Not in an exception block");
 369                         if (exceptionType != null && exceptionType.IsUserType)
 370                                 throw new NotSupportedException ("User defined subclasses of System.Type are not yet supported.");
 371                         if (ex_handlers [cur_block].LastClauseType () == ILExceptionBlock.FILTER_START) {
 372                                 if (exceptionType != null)
 373                                         throw new ArgumentException ("Do not supply an exception type for filter clause");
 374                                 Emit (OpCodes.Endfilter);
 375                                 ex_handlers [cur_block].PatchFilterClause (code_len);
 376                         } else {
 377                                 InternalEndClause ();
 378                                 ex_handlers [cur_block].AddCatch (exceptionType, code_len);
 379                         }
 380
 381                         cur_stack = 1; // the exception object is on the stack by default
 382                         if (max_stack < cur_stack)
 383                                 max_stack = cur_stack;
 384
 385                         //System.Console.WriteLine ("Begin catch Block: {0} {1}",exceptionType.ToString(), max_stack);
 386                 }
 387
 388                 public virtual void BeginExceptFilterBlock ()
 389                 {
 390                         if (open_blocks == null)
 391                                 open_blocks = new Stack (defaultExceptionStackSize);
 392
 393                         if (open_blocks.Count <= 0)
 394                                 throw new NotSupportedException ("Not in an exception block");
 395                         InternalEndClause ();
 396
 397                         ex_handlers [cur_block].AddFilter (code_len);
 398                 }
 399
 400                 public virtual Label BeginExceptionBlock ()
 401                 {
 402                         //System.Console.WriteLine ("Begin Block");
 403                         if (open_blocks == null)
 404                                 open_blocks = new Stack (defaultExceptionStackSize);
 405
 406                         if (ex_handlers != null) {
 407                                 cur_block = ex_handlers.Length;
 408                                 ILExceptionInfo[] new_ex = new ILExceptionInfo [cur_block + 1];
 409                                 System.Array.Copy (ex_handlers, new_ex, cur_block);
 410                                 ex_handlers = new_ex;
 411                         } else {
 412                                 ex_handlers = new ILExceptionInfo [1];
 413                                 cur_block = 0;
 414                         }
 415                         open_blocks.Push (cur_block);
 416                         ex_handlers [cur_block].start = code_len;
 417                         return ex_handlers [cur_block].end = DefineLabel ();
 418                 }
 419
 420                 public virtual void BeginFaultBlock()
 421                 {
 422                         if (open_blocks == null)
 423                                 open_blocks = new Stack (defaultExceptionStackSize);
 424
 425                         if (open_blocks.Count <= 0)
 426                                 throw new NotSupportedException ("Not in an exception block");
 427
 428                         if (ex_handlers [cur_block].LastClauseType () == ILExceptionBlock.FILTER_START) {
 429                                 Emit (OpCodes.Leave, ex_handlers [cur_block].end);
 430                                 ex_handlers [cur_block].PatchFilterClause (code_len);
 431                         }
 432
 433                         InternalEndClause ();
 434                         //System.Console.WriteLine ("Begin fault Block");
 435                         ex_handlers [cur_block].AddFault (code_len);
 436                 }
 437
 438                 public virtual void BeginFinallyBlock()
 439                 {
 440                         if (open_blocks == null)
 441                                 open_blocks = new Stack (defaultExceptionStackSize);
 442
 443                         if (open_blocks.Count <= 0)
 444                                 throw new NotSupportedException ("Not in an exception block");
 445
 446                         InternalEndClause ();
 447
 448                         if (ex_handlers [cur_block].LastClauseType () == ILExceptionBlock.FILTER_START) {
 449                                 Emit (OpCodes.Leave, ex_handlers [cur_block].end);
 450                                 ex_handlers [cur_block].PatchFilterClause (code_len);
 451                         }
 452
 453                         //System.Console.WriteLine ("Begin finally Block");
 454                         ex_handlers [cur_block].AddFinally (code_len);
 455                 }
 456
 457                 public virtual void BeginScope ()
 458                 { }
 459
 460                 public virtual LocalBuilder DeclareLocal (Type localType)
 461                 {
 462                         return DeclareLocal (localType, false);
 463                 }
 464
 465
 466                 public virtual LocalBuilder DeclareLocal (Type localType, bool pinned)
 467                 {
 468                         if (localType == null)
 469                                 throw new ArgumentNullException ("localType");
 470                         if (localType.IsUserType)
 471                                 throw new NotSupportedException ("User defined subclasses of System.Type are not yet supported.");
 472                         LocalBuilder res = new LocalBuilder (localType, this);
 473                         res.is_pinned = pinned;
 474
 475                         if (locals != null) {
 476                                 LocalBuilder[] new_l = new LocalBuilder [locals.Length + 1];
 477                                 System.Array.Copy (locals, new_l, locals.Length);
 478                                 new_l [locals.Length] = res;
 479                                 locals = new_l;
 480                         } else {
 481                                 locals = new LocalBuilder [1];
 482                                 locals [0] = res;
 483                         }
 484                         res.position = (ushort)(locals.Length - 1);
 485                         return res;
 486                 }
 487
 488                 public virtual Label DefineLabel ()
 489                 {
 490                         if (labels == null)
 491                                 labels = new LabelData [defaultLabelsSize];
 492                         else if (num_labels >= labels.Length) {
 493                                 LabelData [] t = new LabelData [labels.Length * 2];
 494                                 Array.Copy (labels, t, labels.Length);
 495                                 labels = t;
 496                         }
 497
 498                         labels [num_labels] = new LabelData (-1, 0);
 499
 500                         return new Label (num_labels++);
 501                 }
 502
 503                 public virtual void Emit (OpCode opcode)
 504                 {
 505                         make_room (2);
 506                         ll_emit (opcode);
 507                 }
 508
 509                 public virtual void Emit (OpCode opcode, Byte arg)
 510                 {
 511                         make_room (3);
 512                         ll_emit (opcode);
 513                         code [code_len++] = arg;
 514                 }
 515
 516                 [ComVisible (true)]
 517                 public virtual void Emit (OpCode opcode, ConstructorInfo con)
 518                 {
 519                         int token = token_gen.GetToken (con);
 520                         make_room (6);
 521                         ll_emit (opcode);
 522                         if (con.DeclaringType.Module == module)
 523                                 add_token_fixup (con);
 524                         emit_int (token);
 525
 526                         if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
 527                                 cur_stack -= con.GetParameterCount ();
 528                 }
 529
 530                 public virtual void Emit (OpCode opcode, double arg)
 531                 {
 532                         byte[] s = System.BitConverter.GetBytes (arg);
 533                         make_room (10);
 534                         ll_emit (opcode);
 535                         if (BitConverter.IsLittleEndian){
 536                                 System.Array.Copy (s, 0, code, code_len, 8);
 537                                 code_len += 8;
 538                         } else {
 539                                 code [code_len++] = s [7];
 540                                 code [code_len++] = s [6];
 541                                 code [code_len++] = s [5];
 542                                 code [code_len++] = s [4];
 543                                 code [code_len++] = s [3];
 544                                 code [code_len++] = s [2];
 545                                 code [code_len++] = s [1];
 546                                 code [code_len++] = s [0];
 547                         }
 548                 }
 549
 550                 public virtual void Emit (OpCode opcode, FieldInfo field)
 551                 {
 552                         int token = token_gen.GetToken (field);
 553                         make_room (6);
 554                         ll_emit (opcode);
 555                         if (field.DeclaringType.Module == module)
 556                                 add_token_fixup (field);
 557                         emit_int (token);
 558                 }
 559
 560                 public virtual void Emit (OpCode opcode, Int16 arg)
 561                 {
 562                         make_room (4);
 563                         ll_emit (opcode);
 564                         code [code_len++] = (byte) (arg & 0xFF);
 565                         code [code_len++] = (byte) ((arg >> 8) & 0xFF);
 566                 }
 567
 568                 public virtual void Emit (OpCode opcode, int arg)
 569                 {
 570                         make_room (6);
 571                         ll_emit (opcode);
 572                         emit_int (arg);
 573                 }
 574
 575                 public virtual void Emit (OpCode opcode, long arg)
 576                 {
 577                         make_room (10);
 578                         ll_emit (opcode);
 579                         code [code_len++] = (byte) (arg & 0xFF);
 580                         code [code_len++] = (byte) ((arg >> 8) & 0xFF);
 581                         code [code_len++] = (byte) ((arg >> 16) & 0xFF);
 582                         code [code_len++] = (byte) ((arg >> 24) & 0xFF);
 583                         code [code_len++] = (byte) ((arg >> 32) & 0xFF);
 584                         code [code_len++] = (byte) ((arg >> 40) & 0xFF);
 585                         code [code_len++] = (byte) ((arg >> 48) & 0xFF);
 586                         code [code_len++] = (byte) ((arg >> 56) & 0xFF);
 587                 }
 588
 589                 public virtual void Emit (OpCode opcode, Label label)
 590                 {
 591                         int tlen = target_len (opcode);
 592                         make_room (6);
 593                         ll_emit (opcode);
 594                         if (cur_stack > labels [label.label].maxStack)
 595                                 labels [label.label].maxStack = cur_stack;
 596
 597                         if (fixups == null)
 598                                 fixups = new LabelFixup [defaultFixupSize];
 599                         else if (num_fixups >= fixups.Length) {
 600                                 LabelFixup[] newf = new LabelFixup [fixups.Length * 2];
 601                                 System.Array.Copy (fixups, newf, fixups.Length);
 602                                 fixups = newf;
 603                         }
 604                         fixups [num_fixups].offset = tlen;
 605                         fixups [num_fixups].pos = code_len;
 606                         fixups [num_fixups].label_idx = label.label;
 607                         num_fixups++;
 608                         code_len += tlen;
 609
 610                 }
 611
 612                 public virtual void Emit (OpCode opcode, Label[] labels)
 613                 {
 614                         if (labels == null)
 615                                 throw new ArgumentNullException ("labels");
 616
 617                         /* opcode needs to be switch. */
 618                         int count = labels.Length;
 619                         make_room (6 + count * 4);
 620                         ll_emit (opcode);
 621
 622                         for (int i = 0; i < count; ++i)
 623                                 if (cur_stack > this.labels [labels [i].label].maxStack)
 624                                         this.labels [labels [i].label].maxStack = cur_stack;
 625
 626                         emit_int (count);
 627                         if (fixups == null)
 628                                 fixups = new LabelFixup [defaultFixupSize + count];
 629                         else if (num_fixups + count >= fixups.Length) {
 630                                 LabelFixup[] newf = new LabelFixup [count + fixups.Length * 2];
 631                                 System.Array.Copy (fixups, newf, fixups.Length);
 632                                 fixups = newf;
 633                         }
 634
 635                         // ECMA 335, Partition III, p94 (7-10)
 636                         //
 637                         // The switch instruction implements a jump table. The format of
 638                         // the instruction is an unsigned int32 representing the number of targets N,
 639                         // followed by N int32 values specifying jump targets: these targets are
 640                         // represented as offsets (positive or negative) from the beginning of the
 641                         // instruction following this switch instruction.
 642                         //
 643                         // We must make sure it gets an offset from the *end* of the last label
 644                         // (eg, the beginning of the instruction following this).
 645                         //
 646                         // remaining is the number of bytes from the current instruction to the
 647                         // instruction that will be emitted.
 648
 649                         for (int i = 0, remaining = count * 4; i < count; ++i, remaining -= 4) {
 650                                 fixups [num_fixups].offset = remaining;
 651                                 fixups [num_fixups].pos = code_len;
 652                                 fixups [num_fixups].label_idx = labels [i].label;
 653                                 num_fixups++;
 654                                 code_len += 4;
 655                         }
 656                 }
 657
 658                 public virtual void Emit (OpCode opcode, LocalBuilder local)
 659                 {
 660                         if (local == null)
 661                                 throw new ArgumentNullException ("local");
 662
 663                         uint pos = local.position;
 664                         bool load_addr = false;
 665                         bool is_store = false;
 666                         make_room (6);
 667
 668                         if (local.ilgen != this)
 669                                 throw new ArgumentException ("Trying to emit a local from a different ILGenerator.");
 670
 671                         /* inline the code from ll_emit () to optimize il code size */
 672                         if (opcode.StackBehaviourPop == StackBehaviour.Pop1) {
 673                                 cur_stack --;
 674                                 is_store = true;
 675                         } else {
 676                                 cur_stack++;
 677                                 if (cur_stack > max_stack)
 678                                         max_stack = cur_stack;
 679                                 load_addr = opcode.StackBehaviourPush == StackBehaviour.Pushi;
 680                         }
 681                         if (load_addr) {
 682                                 if (pos < 256) {
 683                                         code [code_len++] = (byte)0x12;
 684                                         code [code_len++] = (byte)pos;
 685                                 } else {
 686                                         code [code_len++] = (byte)0xfe;
 687                                         code [code_len++] = (byte)0x0d;
 688                                         code [code_len++] = (byte)(pos & 0xff);
 689                                         code [code_len++] = (byte)((pos >> 8) & 0xff);
 690                                 }
 691                         } else {
 692                                 if (is_store) {
 693                                         if (pos < 4) {
 694                                                 code [code_len++] = (byte)(0x0a + pos);
 695                                         } else if (pos < 256) {
 696                                                 code [code_len++] = (byte)0x13;
 697                                                 code [code_len++] = (byte)pos;
 698                                         } else {
 699                                                 code [code_len++] = (byte)0xfe;
 700                                                 code [code_len++] = (byte)0x0e;
 701                                                 code [code_len++] = (byte)(pos & 0xff);
 702                                                 code [code_len++] = (byte)((pos >> 8) & 0xff);
 703                                         }
 704                                 } else {
 705                                         if (pos < 4) {
 706                                                 code [code_len++] = (byte)(0x06 + pos);
 707                                         } else if (pos < 256) {
 708                                                 code [code_len++] = (byte)0x11;
 709                                                 code [code_len++] = (byte)pos;
 710                                         } else {
 711                                                 code [code_len++] = (byte)0xfe;
 712                                                 code [code_len++] = (byte)0x0c;
 713                                                 code [code_len++] = (byte)(pos & 0xff);
 714                                                 code [code_len++] = (byte)((pos >> 8) & 0xff);
 715                                         }
 716                                 }
 717                         }
 718                 }
 719
 720                 public virtual void Emit (OpCode opcode, MethodInfo meth)
 721                 {
 722                         if (meth == null)
 723                                 throw new ArgumentNullException ("meth");
 724
 725                         // For compatibility with MS
 726                         if ((meth is DynamicMethod) && ((opcode == OpCodes.Ldftn) || (opcode == OpCodes.Ldvirtftn) || (opcode == OpCodes.Ldtoken)))
 727                                 throw new ArgumentException ("Ldtoken, Ldftn and Ldvirtftn OpCodes cannot target DynamicMethods.");
 728
 729                         int token = token_gen.GetToken (meth);
 730                         make_room (6);
 731                         ll_emit (opcode);
 732                         Type declaringType = meth.DeclaringType;
 733                         // Might be a DynamicMethod with no declaring type
 734                         if (declaringType != null) {
 735                                 if (declaringType.Module == module)
 736                                         add_token_fixup (meth);
 737                         }
 738                         emit_int (token);
 739                         if (meth.ReturnType != void_type)
 740                                 cur_stack ++;
 741
 742                         if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
 743                                 cur_stack -= meth.GetParameterCount ();
 744                 }
 745
 746                 private void Emit (OpCode opcode, MethodInfo method, int token)
 747                 {
 748                         make_room (6);
 749                         ll_emit (opcode);
 750                         // Might be a DynamicMethod with no declaring type
 751                         Type declaringType = method.DeclaringType;
 752                         if (declaringType != null) {
 753                                 if (declaringType.Module == module)
 754                                         add_token_fixup (method);
 755                         }
 756                         emit_int (token);
 757                         if (method.ReturnType != void_type)
 758                                 cur_stack ++;
 759
 760                         if (opcode.StackBehaviourPop == StackBehaviour.Varpop)
 761                                 cur_stack -= method.GetParameterCount ();
 762                 }
 763
 764                 [CLSCompliant(false)]
 765                 public void Emit (OpCode opcode, sbyte arg)
 766                 {
 767                         make_room (3);
 768                         ll_emit (opcode);
 769                         code [code_len++] = (byte)arg;
 770                 }
 771
 772                 public virtual void Emit (OpCode opcode, SignatureHelper signature)
 773                 {
 774                         int token = token_gen.GetToken (signature);
 775                         make_room (6);
 776                         ll_emit (opcode);
 777                         emit_int (token);
 778                 }
 779
 780                 public virtual void Emit (OpCode opcode, float arg)
 781                 {
 782                         byte[] s = System.BitConverter.GetBytes (arg);
 783                         make_room (6);
 784                         ll_emit (opcode);
 785                         if (BitConverter.IsLittleEndian){
 786                                 System.Array.Copy (s, 0, code, code_len, 4);
 787                                 code_len += 4;
 788                         } else {
 789                                 code [code_len++] = s [3];
 790                                 code [code_len++] = s [2];
 791                                 code [code_len++] = s [1];
 792                                 code [code_len++] = s [0];
 793                         }
 794                 }
 795
 796                 public virtual void Emit (OpCode opcode, string str)
 797                 {
 798                         int token = token_gen.GetToken (str);
 799                         make_room (6);
 800                         ll_emit (opcode);
 801                         emit_int (token);
 802                 }
 803
 804                 public virtual void Emit (OpCode opcode, Type cls)
 805                 {
 806                         make_room (6);
 807                         ll_emit (opcode);
 808                         emit_int (token_gen.GetToken (cls));
 809                 }
 810
 811                 [MonoLimitation ("vararg methods are not supported")]
 812                 public virtual void EmitCall (OpCode opcode, MethodInfo methodInfo, Type[] optionalParameterTypes)
 813                 {
 814                         if (methodInfo == null)
 815                                 throw new ArgumentNullException ("methodInfo");
 816                         short value = opcode.Value;
 817                         if (!(value == OpCodes.Call.Value || value == OpCodes.Callvirt.Value))
 818                                 throw new NotSupportedException ("Only Call and CallVirt are allowed");
 819                         if ((methodInfo.CallingConvention & CallingConventions.VarArgs)  == 0)
 820                                 optionalParameterTypes = null;
 821                         if (optionalParameterTypes != null){
 822                                 if ((methodInfo.CallingConvention & CallingConventions.VarArgs)  == 0){
 823                                         throw new InvalidOperationException ("Method is not VarArgs method and optional types were passed");
 824                                 }
 825
 826                                 int token = token_gen.GetToken (methodInfo, optionalParameterTypes);
 827                                 Emit (opcode, methodInfo, token);
 828                                 return;
 829                         }
 830                         Emit (opcode, methodInfo);
 831                 }
 832
 833                 public virtual void EmitCalli (OpCode opcode, CallingConvention unmanagedCallConv, Type returnType, Type[] parameterTypes)
 834                 {
 835                         SignatureHelper helper = SignatureHelper.GetMethodSigHelper (module, 0, unmanagedCallConv, returnType, parameterTypes);
 836                         Emit (opcode, helper);
 837                 }
 838
 839                 public virtual void EmitCalli (OpCode opcode, CallingConventions callingConvention, Type returnType, Type[] parameterTypes, Type[] optionalParameterTypes)
 840                 {
 841                         if (optionalParameterTypes != null)
 842                                 throw new NotImplementedException ();
 843
 844                         SignatureHelper helper = SignatureHelper.GetMethodSigHelper (module, callingConvention, 0, returnType, parameterTypes);
 845                         Emit (opcode, helper);
 846                 }
 847
 848                 public virtual void EmitWriteLine (FieldInfo fld)
 849                 {
 850                         if (fld == null)
 851                                 throw new ArgumentNullException ("fld");
 852
 853                         // The MS implementation does not check for valuetypes here but it
 854                         // should. Also, it should check that if the field is not static,
 855                         // then it is a member of this type.
 856                         if (fld.IsStatic)
 857                                 Emit (OpCodes.Ldsfld, fld);
 858                         else {
 859                                 Emit (OpCodes.Ldarg_0);
 860                                 Emit (OpCodes.Ldfld, fld);
 861                         }
 862                         Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type[1] { fld.FieldType }));
 863                 }
 864
 865                 public virtual void EmitWriteLine (LocalBuilder localBuilder)
 866                 {
 867                         if (localBuilder == null)
 868                                 throw new ArgumentNullException ("localBuilder");
 869                         if (localBuilder.LocalType is TypeBuilder)
 870                                 throw new  ArgumentException ("Output streams do not support TypeBuilders.");
 871                         // The MS implementation does not check for valuetypes here but it
 872                         // should.
 873                         Emit (OpCodes.Ldloc, localBuilder);
 874                         Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type[1] { localBuilder.LocalType }));
 875                 }
 876
 877                 public virtual void EmitWriteLine (string value)
 878                 {
 879                         Emit (OpCodes.Ldstr, value);
 880                         Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type[1] { typeof(string)}));
 881                 }
 882
 883                 public virtual void EndExceptionBlock ()
 884                 {
 885                         if (open_blocks == null)
 886                                 open_blocks = new Stack (defaultExceptionStackSize);
 887
 888                         if (open_blocks.Count <= 0)
 889                                 throw new NotSupportedException ("Not in an exception block");
 890
 891                         if (ex_handlers [cur_block].LastClauseType () == ILExceptionBlock.FILTER_START)
 892                                 throw new InvalidOperationException ("Incorrect code generation for exception block.");
 893
 894                         InternalEndClause ();
 895                         MarkLabel (ex_handlers [cur_block].end);
 896                         ex_handlers [cur_block].End (code_len);
 897                         ex_handlers [cur_block].Debug (cur_block);
 898                         //System.Console.WriteLine ("End Block {0} (handlers: {1})", cur_block, ex_handlers [cur_block].NumHandlers ());
 899                         open_blocks.Pop ();
 900                         if (open_blocks.Count > 0)
 901                                 cur_block = (int)open_blocks.Peek ();
 902                         //Console.WriteLine ("curblock restored to {0}", cur_block);
 903                         //throw new NotImplementedException ();
 904                 }
 905
 906                 public virtual void EndScope ()
 907                 { }
 908
 909                 public virtual void MarkLabel (Label loc)
 910                 {
 911                         if (loc.label < 0 || loc.label >= num_labels)
 912                                 throw new System.ArgumentException ("The label is not valid");
 913                         if (labels [loc.label].addr >= 0)
 914                                 throw new System.ArgumentException ("The label was already defined");
 915                         labels [loc.label].addr = code_len;
 916                         if (labels [loc.label].maxStack > cur_stack)
 917                                 cur_stack = labels [loc.label].maxStack;
 918                 }
 919
 920                 public virtual void MarkSequencePoint (ISymbolDocumentWriter document, int startLine,
 921                                                        int startColumn, int endLine, int endColumn)
 922                 {
 923                         if (currentSequence == null || currentSequence.Document != document) {
 924                                 if (sequencePointLists == null)
 925                                         sequencePointLists = new ArrayList ();
 926                                 currentSequence = new SequencePointList (document);
 927                                 sequencePointLists.Add (currentSequence);
 928                         }
 929
 930                         currentSequence.AddSequencePoint (code_len, startLine, startColumn, endLine, endColumn);
 931                 }
 932
 933                 internal void GenerateDebugInfo (ISymbolWriter symbolWriter)
 934                 {
 935                         if (sequencePointLists != null) {
 936                                 SequencePointList first = (SequencePointList) sequencePointLists [0];
 937                                 SequencePointList last = (SequencePointList) sequencePointLists [sequencePointLists.Count - 1];
 938                                 symbolWriter.SetMethodSourceRange (first.Document, first.StartLine, first.StartColumn, last.Document, last.EndLine, last.EndColumn);
 939
 940                                 foreach (SequencePointList list in sequencePointLists)
 941                                         symbolWriter.DefineSequencePoints (list.Document, list.GetOffsets(), list.GetLines(), list.GetColumns(), list.GetEndLines(), list.GetEndColumns());
 942
 943                                 if (locals != null) {
 944                                         foreach (LocalBuilder local in locals) {
 945                                                 if (local.Name != null && local.Name.Length > 0) {
 946                                                         SignatureHelper sighelper = SignatureHelper.GetLocalVarSigHelper (module);
 947                                                         sighelper.AddArgument (local.LocalType);
 948                                                         byte[] signature = sighelper.GetSignature ();
 949                                                         symbolWriter.DefineLocalVariable (local.Name, FieldAttributes.Public, signature, SymAddressKind.ILOffset, local.position, 0, 0, local.StartOffset, local.EndOffset);
 950                                                 }
 951                                         }
 952                                 }
 953                                 sequencePointLists = null;
 954                         }
 955                 }
 956
 957                 internal bool HasDebugInfo
 958                 {
 959                         get { return sequencePointLists != null; }
 960                 }
 961
 962                 public virtual void ThrowException (Type excType)
 963                 {
 964                         if (excType == null)
 965                                 throw new ArgumentNullException ("excType");
 966                         if (! ((excType == typeof (Exception)) ||
 967                                    excType.IsSubclassOf (typeof (Exception))))
 968                                 throw new ArgumentException ("Type should be an exception type", "excType");
 969                         ConstructorInfo ctor = excType.GetConstructor (Type.EmptyTypes);
 970                         if (ctor == null)
 971                                 throw new ArgumentException ("Type should have a default constructor", "excType");
 972                         Emit (OpCodes.Newobj, ctor);
 973                         Emit (OpCodes.Throw);
 974                 }
 975
 976                 [MonoTODO("Not implemented")]
 977                 public virtual void UsingNamespace (String usingNamespace)
 978                 {
 979                         throw new NotImplementedException ();
 980                 }
 981
 982                 internal void label_fixup ()
 983                 {
 984                         for (int i = 0; i < num_fixups; ++i) {
 985                                 if (labels [fixups [i].label_idx].addr < 0)
 986                                         throw new ArgumentException ("Label not marked");
 987                                 // Diff is the offset from the end of the jump instruction to the address of the label
 988                                 int diff = labels [fixups [i].label_idx].addr - (fixups [i].pos + fixups [i].offset);
 989                                 if (fixups [i].offset == 1) {
 990                                         code [fixups [i].pos] = (byte)((sbyte) diff);
 991                                 } else {
 992                                         int old_cl = code_len;
 993                                         code_len = fixups [i].pos;
 994                                         emit_int (diff);
 995                                         code_len = old_cl;
 996                                 }
 997                         }
 998                 }
 999
1000                 // Still used by symbolwriter
1001                 [Obsolete ("Use ILOffset", true)]
1002                 internal static int Mono_GetCurrentOffset (ILGenerator ig)
1003                 {
1004                         return ig.code_len;
1005                 }
1006
1007 #if NET_4_0 || BOOTSTRAP_NET_4_0
1008                 public
1009 #else
1010                 internal
1011 #endif
1012                 virtual int ILOffset {
1013                         get { return code_len; }
1014                 }
1015
1016                 void _ILGenerator.GetIDsOfNames ([In] ref Guid riid, IntPtr rgszNames, uint cNames, uint lcid, IntPtr rgDispId)
1017                 {
1018                         throw new NotImplementedException ();
1019                 }
1020
1021                 void _ILGenerator.GetTypeInfo (uint iTInfo, uint lcid, IntPtr ppTInfo)
1022                 {
1023                         throw new NotImplementedException ();
1024                 }
1025
1026                 void _ILGenerator.GetTypeInfoCount (out uint pcTInfo)
1027                 {
1028                         throw new NotImplementedException ();
1029                 }
1030
1031                 void _ILGenerator.Invoke (uint dispIdMember, [In] ref Guid riid, uint lcid, short wFlags, IntPtr pDispParams, IntPtr pVarResult, IntPtr pExcepInfo, IntPtr puArgErr)
1032                 {
1033                         throw new NotImplementedException ();
1034                 }
1035         }
1036
1037         internal class SequencePointList
1038         {
1039                 ISymbolDocumentWriter doc;
1040                 SequencePoint[] points;
1041                 int count;
1042                 const int arrayGrow = 10;
1043
1044                 public SequencePointList (ISymbolDocumentWriter doc)
1045                 {
1046                         this.doc = doc;
1047                 }
1048
1049                 public ISymbolDocumentWriter Document {
1050                         get { return doc; }
1051                 }
1052
1053                 public int[] GetOffsets()
1054                 {
1055                         int[] data = new int [count];
1056                         for (int n=0; n<count; n++) data [n] = points[n].Offset;
1057                         return data;
1058                 }
1059                 public int[] GetLines()
1060                 {
1061                         int[] data = new int [count];
1062                         for (int n=0; n<count; n++) data [n] = points[n].Line;
1063                         return data;
1064                 }
1065                 public int[] GetColumns()
1066                 {
1067                         int[] data = new int [count];
1068                         for (int n=0; n<count; n++) data [n] = points[n].Col;
1069                         return data;
1070                 }
1071                 public int[] GetEndLines()
1072                 {
1073                         int[] data = new int [count];
1074                         for (int n=0; n<count; n++) data [n] = points[n].EndLine;
1075                         return data;
1076                 }
1077                 public int[] GetEndColumns()
1078                 {
1079                         int[] data = new int [count];
1080                         for (int n=0; n<count; n++) data [n] = points[n].EndCol;
1081                         return data;
1082                 }
1083                 public int StartLine {
1084                         get { return points[0].Line; }
1085                 }
1086                 public int EndLine {
1087                         get { return points[count - 1].Line; }
1088                 }
1089                 public int StartColumn {
1090                         get { return points[0].Col; }
1091                 }
1092                 public int EndColumn {
1093                         get { return points[count - 1].Col; }
1094                 }
1095
1096                 public void AddSequencePoint (int offset, int line, int col, int endLine, int endCol)
1097                 {
1098                         SequencePoint s = new SequencePoint ();
1099                         s.Offset = offset;
1100                         s.Line = line;
1101                         s.Col = col;
1102                         s.EndLine = endLine;
1103                         s.EndCol = endCol;
1104
1105                         if (points == null) {
1106                                 points = new SequencePoint [arrayGrow];
1107                         } else if (count >= points.Length) {
1108                                 SequencePoint[] temp = new SequencePoint [count + arrayGrow];
1109                                 Array.Copy (points, temp, points.Length);
1110                                 points = temp;
1111                         }
1112
1113                         points [count] = s;
1114                         count++;
1115                 }
1116         }
1117
1118         struct SequencePoint {
1119                 public int Offset;
1120                 public int Line;
1121                 public int Col;
1122                 public int EndLine;
1123                 public int EndCol;
1124         }
1125 }