mcs/class/System/System.Text.RegularExpressions/CILCompiler.cs

   1 using System;
   2 using System.Collections;
   3 using System.Globalization;
   4 using System.Reflection;
   5 using System.Reflection.Emit;
   6 using System.Threading;
   7
   8 using System.Collections.Generic;
   9
  10 namespace System.Text.RegularExpressions {
  11
  12         //
  13         // Compiler which generates IL bytecode to perform the matching instead of
  14         // interpreting a program.
  15         // For simplicity, we inherit from RxCompiler, and generate the IL code based
  16         // on the program generated by it. This also allows us to fallback to interpretation
  17         // if we can't handle something.
  18         // This is net 2.0, since 1.0 doesn't support DynamicMethods
  19         // FIXME: Add support for 1.0, and CompileToAssembly
  20         // FIXME: Overwrite RxCompiler methods so we don't have to decode char
  21         // matching opcodes
  22         //
  23
  24         class CILCompiler : RxCompiler, ICompiler {
  25                 DynamicMethod[] eval_methods;
  26                 bool[] eval_methods_defined;
  27
  28                 /*
  29                  * To avoid the overhead of decoding the countless opcode variants created
  30                  * by RxCompiler, we save the original, 'generic' version and its flags
  31                  * in these two tables.
  32                  */
  33                 private Dictionary<int, int> generic_ops;
  34                 private Dictionary<int, int> op_flags;
  35                 private Dictionary<int, Label> labels;
  36
  37                 static FieldInfo fi_str = typeof (RxInterpreter).GetField ("str", BindingFlags.Instance|BindingFlags.NonPublic);
  38                 static FieldInfo fi_string_start = typeof (RxInterpreter).GetField ("string_start", BindingFlags.Instance|BindingFlags.NonPublic);
  39                 static FieldInfo fi_string_end = typeof (RxInterpreter).GetField ("string_end", BindingFlags.Instance|BindingFlags.NonPublic);
  40                 static FieldInfo fi_program = typeof (RxInterpreter).GetField ("program", BindingFlags.Instance|BindingFlags.NonPublic);
  41                 static FieldInfo fi_marks = typeof (RxInterpreter).GetField ("marks", BindingFlags.Instance|BindingFlags.NonPublic);
  42                 static FieldInfo fi_groups = typeof (RxInterpreter).GetField ("groups", BindingFlags.Instance|BindingFlags.NonPublic);
  43                 static FieldInfo fi_deep = typeof (RxInterpreter).GetField ("deep", BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
  44                 static FieldInfo fi_stack = typeof (RxInterpreter).GetField ("stack", BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
  45                 static FieldInfo fi_mark_start = typeof (Mark).GetField ("Start", BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
  46                 static FieldInfo fi_mark_end = typeof (Mark).GetField ("End", BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
  47                 //static FieldInfo fi_mark_index = typeof (Mark).GetField ("Index", BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
  48
  49                 static MethodInfo mi_stack_get_count, mi_stack_set_count, mi_stack_push, mi_stack_pop;
  50                 static MethodInfo mi_set_start_of_match, mi_is_word_char, mi_reset_groups;
  51                 static MethodInfo mi_checkpoint, mi_backtrack, mi_open, mi_close;
  52                 static MethodInfo mi_get_last_defined, mi_mark_get_index, mi_mark_get_length;
  53
  54                 public static readonly bool trace_compile = Environment.GetEnvironmentVariable ("MONO_TRACE_RX_COMPILE") != null;
  55
  56                 public CILCompiler () {
  57                         generic_ops = new Dictionary <int, int> ();
  58                         op_flags = new Dictionary <int, int> ();
  59                 }
  60
  61                 IMachineFactory ICompiler.GetMachineFactory () {
  62                         byte[] code = new byte [curpos];
  63                         Buffer.BlockCopy (program, 0, code, 0, curpos);
  64
  65                         eval_methods = new DynamicMethod [code.Length];
  66                         eval_methods_defined = new bool [code.Length];
  67
  68                         // The main eval method
  69                     DynamicMethod main = GetEvalMethod (code, 11);
  70
  71                         if (main != null)
  72                                 return new RxInterpreterFactory (code, (EvalDelegate)main.CreateDelegate (typeof (EvalDelegate)));
  73                         else
  74                                 return new RxInterpreterFactory (code, null);
  75                 }
  76
  77                 DynamicMethod GetEvalMethod (byte[] program, int pc) {
  78                         if (eval_methods_defined [pc])
  79                                 return eval_methods [pc];
  80
  81                         // FIXME: Recursion ?
  82                         eval_methods_defined [pc] = true;
  83
  84                         eval_methods [pc] = CreateEvalMethod (program, pc);
  85                         return eval_methods [pc];
  86                 }
  87
  88                 private MethodInfo GetMethod (Type t, string name, ref MethodInfo cached) {
  89                         if (cached == null) {
  90                                 cached = t.GetMethod (name, BindingFlags.Static|BindingFlags.Instance|BindingFlags.Public|BindingFlags.NonPublic);
  91                                 if (cached == null)
  92                                         throw new Exception ("Method not found: " + name);
  93                         }
  94                         return cached;
  95                 }
  96
  97                 private MethodInfo GetMethod (string name, ref MethodInfo cached) {
  98                         return GetMethod (typeof (RxInterpreter), name, ref cached);
  99             }
 100
 101                 private int ReadInt (byte[] code, int pc) {
 102                         int val = code [pc];
 103                         val |= code [pc + 1] << 8;
 104                         val |= code [pc + 2] << 16;
 105                         val |= code [pc + 3] << 24;
 106                         return val;
 107                 }
 108
 109                 static OpFlags MakeFlags (bool negate, bool ignore, bool reverse, bool lazy) {
 110                         OpFlags flags = 0;
 111                         if (negate) flags |= OpFlags.Negate;
 112                         if (ignore) flags |= OpFlags.IgnoreCase;
 113                         if (reverse) flags |= OpFlags.RightToLeft;
 114                         if (lazy) flags |= OpFlags.Lazy;
 115
 116                         return flags;
 117                 }
 118
 119                 void EmitGenericOp (RxOp op, bool negate, bool ignore, bool reverse, bool lazy) {
 120                         generic_ops [curpos] = (int)op;
 121                         op_flags [curpos] = (int)MakeFlags (negate, ignore, reverse, false);
 122             }
 123
 124                 public override void EmitOp (RxOp op, bool negate, bool ignore, bool reverse) {
 125                         EmitGenericOp (op, negate, ignore, reverse, false);
 126                         base.EmitOp (op, negate, ignore, reverse);
 127                 }
 128
 129                 public override void EmitOpIgnoreReverse (RxOp op, bool ignore, bool reverse) {
 130                         EmitGenericOp (op, false, ignore, reverse, false);
 131                         base.EmitOpIgnoreReverse (op, ignore, reverse);
 132                 }
 133
 134                 public override void EmitOpNegateReverse (RxOp op, bool negate, bool reverse) {
 135                         EmitGenericOp (op, negate, false, reverse, false);
 136                         base.EmitOpNegateReverse (op, negate, reverse);
 137                 }
 138
 139                 class Frame {
 140                         public Label label_pass, label_fail;
 141
 142                         public Frame (ILGenerator ilgen) {
 143                                 label_fail = ilgen.DefineLabel ();
 144                                 label_pass = ilgen.DefineLabel ();
 145                         }
 146                 }
 147
 148                 LocalBuilder local_textinfo;
 149
 150                 /*
 151                  * Create a dynamic method which is equivalent to the RxInterpreter.EvalByteCode
 152                  * method specialized to the given program and a given pc. Return the newly
 153                  * created method or null if a not-supported opcode was encountered.
 154                  */
 155                 DynamicMethod CreateEvalMethod (byte[] program, int pc) {
 156                         DynamicMethod m = new DynamicMethod ("Eval_" + pc, typeof (bool), new Type [] { typeof (RxInterpreter), typeof (int), typeof (int).MakeByRefType () }, typeof (RxInterpreter), true);
 157                         ILGenerator ilgen = m.GetILGenerator ();
 158
 159                         /*
 160                            Args:
 161                            interp - 0
 162                            strpos - 1
 163                            strpos_result - 2
 164                         */
 165
 166                         /*
 167                          * Recursive calls to EvalByteCode are inlined manually by calling
 168                          * EmitEvalMethodBody with the pc of the recursive call. Frame objects hold
 169                          * the information required to link together the code generated by the recursive
 170                          * call with the rest of the code.
 171                          */
 172                         Frame frame = new Frame (ilgen);
 173
 174                         /* Cache the textinfo used by Char.ToLower () */
 175                         local_textinfo = ilgen.DeclareLocal (typeof (TextInfo));
 176                         ilgen.Emit (OpCodes.Call, typeof (Thread).GetMethod ("get_CurrentThread"));
 177                         ilgen.Emit (OpCodes.Call, typeof (Thread).GetMethod ("get_CurrentCulture"));
 178                         ilgen.Emit (OpCodes.Call, typeof (CultureInfo).GetMethod ("get_TextInfo"));
 179                         ilgen.Emit (OpCodes.Stloc, local_textinfo);
 180
 181                         m = EmitEvalMethodBody (m, ilgen, frame, program, pc, program.Length, false, false, out pc);
 182                         if (m == null)
 183                                 return null;
 184
 185                         ilgen.MarkLabel (frame.label_pass);
 186                         ilgen.Emit (OpCodes.Ldarg_2);
 187                         ilgen.Emit (OpCodes.Ldarg_1);
 188                         ilgen.Emit (OpCodes.Stind_I4);
 189                         ilgen.Emit (OpCodes.Ldc_I4_1);
 190                         ilgen.Emit (OpCodes.Ret);
 191
 192                         ilgen.MarkLabel (frame.label_fail);
 193                         ilgen.Emit (OpCodes.Ldc_I4_0);
 194                         ilgen.Emit (OpCodes.Ret);
 195
 196                         return m;
 197                 }
 198
 199                 private int ReadShort (byte[] program, int pc) {
 200                         return (int)program [pc] | ((int)program [pc + 1] << 8);
 201                 }
 202
 203                 private Label CreateLabelForPC (ILGenerator ilgen, int pc) {
 204                         if (labels == null)
 205                                 labels = new Dictionary <int, Label> ();
 206                         Label l;
 207                         if (!labels.TryGetValue (pc, out l)) {
 208                                 l = ilgen.DefineLabel ();
 209                                 labels [pc] = l;
 210                         }
 211
 212                         return l;
 213                 }
 214
 215                 private int GetILOffset (ILGenerator ilgen) {
 216                         return (int)typeof (ILGenerator).GetField ("code_len", BindingFlags.Instance|BindingFlags.NonPublic).GetValue (ilgen);
 217                 }
 218
 219                 /*
 220                  * Emit IL code for a sequence of opcodes between pc and end_pc. If there is a
 221                  * match, set strpos (Arg 1) to the position after the match, then
 222                  * branch to frame.label_pass. Otherwise branch to frame.label_fail,
 223                  * and leave strpos at an undefined position. The caller should
 224                  * generate code to save the original value of strpos if it needs it.
 225                  * If one_op is true, only generate code for one opcode and set out_pc
 226                  * to the next pc after the opcode.
 227                  * If no_bump is true, don't bump strpos in char matching opcodes.
 228                  * Keep this in synch with RxInterpreter.EvalByteCode (). It it is sync with
 229                  * the version in r111969.
 230                  * FIXME: Modify the regex tests so they are run with RegexOptions.Compiled as
 231                  * well.
 232                  */
 233                 private DynamicMethod EmitEvalMethodBody (DynamicMethod m, ILGenerator ilgen,
 234                                                                                                   Frame frame, byte[] program,
 235                                                                                                   int pc, int end_pc,
 236                                                                                                   bool one_op, bool no_bump,
 237                                                                                                   out int out_pc)
 238                 {
 239                         int start, length, end;
 240
 241                         out_pc = 0;
 242
 243                         int group_count = 1 + ReadShort (program, 1);
 244
 245                         while (pc < end_pc) {
 246                                 RxOp op = (RxOp)program [pc];
 247
 248                                 // FIXME: Optimize this
 249                                 if (generic_ops.ContainsKey (pc))
 250                                         op = (RxOp)generic_ops [pc];
 251
 252                                 if (trace_compile) {
 253                                         Console.WriteLine ("compiling {0} pc={1} end_pc={2}, il_offset=0x{3:x}", op, pc, end_pc, GetILOffset (ilgen));
 254                                 }
 255
 256                                 if (labels != null) {
 257                                         Label l;
 258                                         if (labels.TryGetValue (pc, out l)) {
 259                                                 ilgen.MarkLabel (l);
 260                                                 labels.Remove (pc);
 261                                         }
 262                                 }
 263
 264                                 if (RxInterpreter.trace_rx) {
 265                                         //Console.WriteLine ("evaluating: {0} at pc: {1}, strpos: {2}", op, pc, strpos);
 266                                         ilgen.Emit (OpCodes.Ldstr, "evaluating: {0} at pc: {1}, strpos: {2}");
 267                                         ilgen.Emit (OpCodes.Ldc_I4, (int)op);
 268                                         ilgen.Emit (OpCodes.Box, typeof (RxOp));
 269                                         ilgen.Emit (OpCodes.Ldc_I4, pc);
 270                                         ilgen.Emit (OpCodes.Box, typeof (int));
 271                                         ilgen.Emit (OpCodes.Ldarg_1);
 272                                         ilgen.Emit (OpCodes.Box, typeof (int));
 273                                         ilgen.Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type [] { typeof (string), typeof (object), typeof (object), typeof (object) }));
 274                                 }
 275
 276                                 switch (op) {
 277                                 case RxOp.Anchor:
 278                                 case RxOp.AnchorReverse: {
 279                                         bool reverse = (RxOp)program [pc] == RxOp.AnchorReverse;
 280                                         length = ReadShort (program, pc + 3);
 281                                         pc += ReadShort (program, pc + 1);
 282
 283                                         // Optimize some common cases by inlining the code generated for the
 284                                         // anchor body
 285                                         RxOp anch_op = (RxOp)program [pc];
 286
 287                                         // FIXME: Do this even if the archor op is not the last in the regex
 288                                         if (!reverse && group_count == 1 && anch_op == RxOp.Char && (RxOp)program [pc + 2] == RxOp.True) {
 289
 290                                                 /*
 291                                                  * while (strpos < string_end) {
 292                                                  *   if (str [strpos] == program [pc + 1]) {
 293                                                  *     match_start = strpos;
 294                                                  *     strpos_result = strpos + 1;
 295                                                  *     marks [groups [0]].Start = strpos;
 296                                                  *     if (groups.Length > 1)
 297                                                  *              marks [groups [0]].End = res;
 298                                                  *     return true;
 299                                                  *   }
 300                                                  *   strpos ++;
 301                                                  * }
 302                                                  * return false;
 303                                                  */
 304                                                 // Add some locals to avoid an indirection
 305                                                 LocalBuilder local_string_end = ilgen.DeclareLocal (typeof (int));
 306                                                 ilgen.Emit (OpCodes.Ldarg_0);
 307                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 308                                                 ilgen.Emit (OpCodes.Stloc, local_string_end);
 309                                                 LocalBuilder local_str = ilgen.DeclareLocal (typeof (string));
 310                                                 ilgen.Emit (OpCodes.Ldarg_0);
 311                                                 ilgen.Emit (OpCodes.Ldfld, fi_str);
 312                                                 ilgen.Emit (OpCodes.Stloc, local_str);
 313
 314                                                 //while (strpos < string_end) {
 315                                                 // -> Done at the end of the loop like mcs does
 316                                                 Label l1 = ilgen.DefineLabel ();
 317                                                 Label l2 = ilgen.DefineLabel ();
 318                                                 ilgen.Emit (OpCodes.Br, l2);
 319                                                 ilgen.MarkLabel (l1);
 320
 321                                                 //  if (str [strpos] == program [pc + 1]) {
 322                                                 Label l3 = ilgen.DefineLabel ();
 323                                                 ilgen.Emit (OpCodes.Ldloc, local_str);
 324                                                 ilgen.Emit (OpCodes.Ldarg_1);
 325                                                 ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 326                                                 ilgen.Emit (OpCodes.Conv_I4);
 327                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 1]);
 328                                                 ilgen.Emit (OpCodes.Beq, l3);
 329
 330                                                 // The true case is done after the loop
 331
 332                                                 //  }
 333                                                 //  strpos++;
 334                                                 ilgen.Emit (OpCodes.Ldarg_1);
 335                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 336                                                 ilgen.Emit (OpCodes.Add);
 337                                                 ilgen.Emit (OpCodes.Starg, 1);
 338                                                 //}
 339                                                 ilgen.MarkLabel (l2);
 340                                                 ilgen.Emit (OpCodes.Ldarg_1);
 341                                                 ilgen.Emit (OpCodes.Ldloc, local_string_end);
 342                                                 ilgen.Emit (OpCodes.Blt, l1);
 343
 344                                                 //return false;
 345                                                 ilgen.Emit (OpCodes.Br, frame.label_fail);
 346
 347                                                 // True case
 348                                                 ilgen.MarkLabel (l3);
 349                                                 // call SetStartOfMatch (strpos)
 350                                                 ilgen.Emit (OpCodes.Ldarg_0);
 351                                                 ilgen.Emit (OpCodes.Ldarg_1);
 352                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter), "SetStartOfMatch", ref mi_set_start_of_match));
 353                                                 //  strpos++;
 354                                                 ilgen.Emit (OpCodes.Ldarg_1);
 355                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 356                                                 ilgen.Emit (OpCodes.Add);
 357                                                 ilgen.Emit (OpCodes.Starg, 1);
 358                                                 //    return true;
 359                                                 ilgen.Emit (OpCodes.Br, frame.label_pass);
 360
 361                                         } else {
 362                                                 // General case
 363
 364                                                 //Console.WriteLine ("Anchor op " + anch_op);
 365
 366                                                 // Add some locals to avoid an indirection
 367                                                 LocalBuilder local_string_end = ilgen.DeclareLocal (typeof (int));
 368                                                 ilgen.Emit (OpCodes.Ldarg_0);
 369                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 370                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 371                                                 ilgen.Emit (OpCodes.Add);
 372                                                 ilgen.Emit (OpCodes.Stloc, local_string_end);
 373
 374                                                 //while (strpos < string_end + 1) {
 375                                                 // -> Done at the end of the loop like mcs does
 376                                                 Label l1 = ilgen.DefineLabel ();
 377                                                 Label l2 = ilgen.DefineLabel ();
 378                                                 ilgen.Emit (OpCodes.Br, l2);
 379                                                 ilgen.MarkLabel (l1);
 380
 381                                                 //if (groups.Length > 1) {
 382                                                 //      ResetGroups ();
 383                                                 //      marks [groups [0]].Start = strpos;
 384                                                 //}
 385                                                 if (group_count > 1) {
 386                                                         ilgen.Emit (OpCodes.Ldarg_0);
 387                                                         ilgen.Emit (OpCodes.Call, GetMethod ("ResetGroups", ref mi_reset_groups));
 388
 389                                                         ilgen.Emit (OpCodes.Ldarg_0);
 390                                                         ilgen.Emit (OpCodes.Ldfld, fi_marks);
 391                                                         ilgen.Emit (OpCodes.Ldarg_0);
 392                                                         ilgen.Emit (OpCodes.Ldfld, fi_groups);
 393                                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 394                                                         ilgen.Emit (OpCodes.Ldelem_I4);
 395                                                         ilgen.Emit (OpCodes.Ldelema, typeof (Mark));
 396                                                         ilgen.Emit (OpCodes.Ldarg_1);
 397                                                         ilgen.Emit (OpCodes.Stfld, fi_mark_start);
 398                                                 }
 399
 400                                                 //  if (EvalByteCode (pc, strpos, ref res)) {
 401
 402                                                 Frame new_frame = new Frame (ilgen);
 403
 404                                                 //  old_stros = strpos;
 405                                                 LocalBuilder local_old_strpos = ilgen.DeclareLocal (typeof (int));
 406                                                 ilgen.Emit (OpCodes.Ldarg_1);
 407                                                 ilgen.Emit (OpCodes.Stloc, local_old_strpos);
 408
 409                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc, end_pc, false, false, out out_pc);
 410                                                 if (m == null)
 411                                                         return null;
 412
 413                                                 // Pass
 414                                                 ilgen.MarkLabel (new_frame.label_pass);
 415                                                 //    marks [groups [0]].Start = old_strpos;
 416                                                 ilgen.Emit (OpCodes.Ldarg_0);
 417                                                 ilgen.Emit (OpCodes.Ldfld, fi_marks);
 418                                                 ilgen.Emit (OpCodes.Ldarg_0);
 419                                                 ilgen.Emit (OpCodes.Ldfld, fi_groups);
 420                                                 ilgen.Emit (OpCodes.Ldc_I4_0);
 421                                                 ilgen.Emit (OpCodes.Ldelem_I4);
 422                                                 ilgen.Emit (OpCodes.Ldelema, typeof (Mark));
 423                                                 ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
 424                                                 ilgen.Emit (OpCodes.Stfld, fi_mark_start);
 425                                                 //    if (groups.Length > 1)
 426                                                 //              marks [groups [0]].End = res;
 427                                                 if (group_count > 1) {
 428                                                         ilgen.Emit (OpCodes.Ldarg_0);
 429                                                         ilgen.Emit (OpCodes.Ldfld, fi_marks);
 430                                                         ilgen.Emit (OpCodes.Ldarg_0);
 431                                                         ilgen.Emit (OpCodes.Ldfld, fi_groups);
 432                                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 433                                                         ilgen.Emit (OpCodes.Ldelem_I4);
 434                                                         ilgen.Emit (OpCodes.Ldelema, typeof (Mark));
 435                                                         ilgen.Emit (OpCodes.Ldarg_1);
 436                                                         ilgen.Emit (OpCodes.Stfld, fi_mark_end);
 437                                                 }
 438
 439                                                 //    return true;
 440                                                 ilgen.Emit (OpCodes.Br, frame.label_pass);
 441
 442                                                 // Fail
 443                                                 ilgen.MarkLabel (new_frame.label_fail);
 444                                                 //  strpos = old_strpos +/- 1;
 445                                                 ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
 446                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 447                                                 if (reverse)
 448                                                         ilgen.Emit (OpCodes.Sub);
 449                                                 else
 450                                                         ilgen.Emit (OpCodes.Add);
 451                                                 ilgen.Emit (OpCodes.Starg, 1);
 452                                                 //}
 453                                                 ilgen.MarkLabel (l2);
 454                                                 if (reverse) {
 455                                                         ilgen.Emit (OpCodes.Ldarg_1);
 456                                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 457                                                         ilgen.Emit (OpCodes.Bge, l1);
 458                                                 } else {
 459                                                         ilgen.Emit (OpCodes.Ldarg_1);
 460                                                         ilgen.Emit (OpCodes.Ldloc, local_string_end);
 461                                                         ilgen.Emit (OpCodes.Blt, l1);
 462                                                 }
 463                                                 //return false;
 464                                                 ilgen.Emit (OpCodes.Br, frame.label_fail);
 465                                         }
 466
 467                                         goto End;
 468                                 }
 469                                 case RxOp.Branch: {
 470                                         //if (EvalByteCode (pc + 3, strpos, ref res)) {
 471
 472                                         int target_pc = pc + ReadShort (program, pc + 1);
 473
 474                                         // Emit the rest of the code inline instead of making a recursive call
 475                                         Frame new_frame = new Frame (ilgen);
 476
 477                                         //  old_strpos = strpos;
 478                                         LocalBuilder local_old_strpos = ilgen.DeclareLocal (typeof (int));
 479                                         ilgen.Emit (OpCodes.Ldarg_1);
 480                                         ilgen.Emit (OpCodes.Stloc, local_old_strpos);
 481
 482                                         m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc + 3, target_pc, false, false, out out_pc);
 483                                         if (m == null)
 484                                                 return null;
 485
 486                                         // Pass
 487                                         ilgen.MarkLabel (new_frame.label_pass);
 488                                         //  return true;
 489                                         ilgen.Emit (OpCodes.Br, frame.label_pass);
 490
 491                                         // Fail
 492                                         ilgen.MarkLabel (new_frame.label_fail);
 493                                         //  strpos = old_strpos;
 494                                         ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
 495                                         ilgen.Emit (OpCodes.Starg, 1);
 496
 497                                         pc = target_pc;
 498                                         break;
 499                                 }
 500                                 case RxOp.Char:
 501                                 case RxOp.UnicodeChar:
 502                                 case RxOp.Range:
 503                                 case RxOp.UnicodeRange: {
 504                                         OpFlags flags = (OpFlags)op_flags [pc];
 505                                         bool negate = (flags & OpFlags.Negate) > 0;
 506                                         bool ignore = (flags & OpFlags.IgnoreCase) > 0;
 507                                         bool reverse = (flags & OpFlags.RightToLeft) > 0;
 508
 509                                         //if (strpos < string_end) {
 510                                         Label l1 = ilgen.DefineLabel ();
 511                                         if (reverse) {
 512                                                 ilgen.Emit (OpCodes.Ldarg_1);
 513                                                 ilgen.Emit (OpCodes.Ldc_I4_0);
 514                                                 ilgen.Emit (OpCodes.Ble, l1);
 515                                         } else {
 516                                                 ilgen.Emit (OpCodes.Ldarg_1);
 517                                                 ilgen.Emit (OpCodes.Ldarg_0);
 518                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 519                                                 ilgen.Emit (OpCodes.Bge, l1);
 520                                         }
 521
 522                                         if (ignore)
 523                                                 ilgen.Emit (OpCodes.Ldloc, local_textinfo);
 524
 525                                         //  int c = str [strpos];
 526                                         LocalBuilder local_c = ilgen.DeclareLocal (typeof (char));
 527                                         ilgen.Emit (OpCodes.Ldarg_0);
 528                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 529                                         ilgen.Emit (OpCodes.Ldarg_1);
 530                                         if (reverse) {
 531                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 532                                                 ilgen.Emit (OpCodes.Sub);
 533                                         }
 534                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 535                                         if (ignore)
 536                                                 ilgen.Emit (OpCodes.Callvirt, typeof (TextInfo).GetMethod ("ToLower", new Type [] { typeof (char) }));
 537
 538                                         if (op == RxOp.Char) {
 539                                                 ilgen.Emit (OpCodes.Conv_I4);
 540                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 1]);
 541                                                 ilgen.Emit (negate ? OpCodes.Beq : OpCodes.Bne_Un, l1);
 542
 543                                                 pc += 2;
 544                                         } else if (op == RxOp.UnicodeChar) {
 545                                                 ilgen.Emit (OpCodes.Conv_I4);
 546                                                 ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 1));
 547                                                 ilgen.Emit (negate ? OpCodes.Beq : OpCodes.Bne_Un, l1);
 548
 549                                                 pc += 3;
 550                                         } else if (op == RxOp.Range) {
 551                                                 ilgen.Emit (OpCodes.Stloc, local_c);
 552
 553                                                 //  if (c >= program [pc + 1] && c <= program [pc + 2]) {
 554                                                 if (negate) {
 555                                                         Label l3 = ilgen.DefineLabel ();
 556
 557                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 558                                                         ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 1]);
 559                                                         ilgen.Emit (OpCodes.Blt, l3);
 560                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 561                                                         ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 2]);
 562                                                         ilgen.Emit (OpCodes.Bgt, l3);
 563                                                         ilgen.Emit (OpCodes.Br, l1);
 564                                                         ilgen.MarkLabel (l3);
 565                                                 } else {
 566                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 567                                                         ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 1]);
 568                                                         ilgen.Emit (OpCodes.Blt, l1);
 569                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 570                                                         ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 2]);
 571                                                         ilgen.Emit (OpCodes.Bgt, l1);
 572                                                 }
 573
 574                                                 pc += 3;
 575                                         } else if (op == RxOp.UnicodeRange) {
 576                                                 ilgen.Emit (OpCodes.Stloc, local_c);
 577
 578                                                 //  if (c >= program [pc + 1] && c <= program [pc + 2]) {
 579                                                 if (negate) {
 580                                                         Label l3 = ilgen.DefineLabel ();
 581
 582                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 583                                                         ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 1));
 584                                                         ilgen.Emit (OpCodes.Blt, l3);
 585                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 586                                                         ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 3));
 587                                                         ilgen.Emit (OpCodes.Bgt, l3);
 588                                                         ilgen.Emit (OpCodes.Br, l1);
 589                                                         ilgen.MarkLabel (l3);
 590                                                 } else {
 591                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 592                                                         ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 1));
 593                                                         ilgen.Emit (OpCodes.Blt, l1);
 594                                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 595                                                         ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 3));
 596                                                         ilgen.Emit (OpCodes.Bgt, l1);
 597                                                 }
 598
 599                                                 pc += 5;
 600                                         } else {
 601                                                 throw new NotSupportedException ();
 602                                         }
 603
 604                                         //ilgen.EmitWriteLine ("HIT:" + (char)program [pc + 1]);
 605                                         if (!no_bump) {
 606                                                 //  strpos++ / strpos--;
 607                                                 ilgen.Emit (OpCodes.Ldarg_1);
 608                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 609                                                 if (reverse)
 610                                                         ilgen.Emit (OpCodes.Sub);
 611                                                 else
 612                                                         ilgen.Emit (OpCodes.Add);
 613                                                 ilgen.Emit (OpCodes.Starg, 1);
 614                                         }
 615                                         Label l2 = ilgen.DefineLabel ();
 616                                         ilgen.Emit (OpCodes.Br, l2);
 617                                         //}
 618                                         ilgen.MarkLabel (l1);
 619                                         //return false;
 620                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
 621                                         ilgen.MarkLabel (l2);
 622
 623                                         break;
 624                                 }
 625                                 case RxOp.True: {
 626                                         //  return true;
 627                                         ilgen.Emit (OpCodes.Br, frame.label_pass);
 628                                         pc++;
 629                                         break;
 630                                 }
 631                                 case RxOp.False: {
 632                                         //  return false;
 633                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
 634                                         pc++;
 635                                         break;
 636                                 }
 637                                 case RxOp.AnyPosition: {
 638                                         pc++;
 639                                         break;
 640                                 }
 641                                 case RxOp.StartOfString: {
 642                                         //if (strpos != 0)
 643                                         //      return false;
 644                                         ilgen.Emit (OpCodes.Ldarg_1);
 645                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 646                                         ilgen.Emit (OpCodes.Bgt, frame.label_fail);
 647                                         pc++;
 648                                         break;
 649                                 }
 650                                 case RxOp.StartOfLine: {
 651                                         // FIXME: windows line endings
 652                                         //if (!(strpos == 0 || str [strpos - 1] == '\n'))
 653                                         //      return false;
 654                                         Label l = ilgen.DefineLabel ();
 655                                         ilgen.Emit (OpCodes.Ldarg_1);
 656                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 657                                         ilgen.Emit (OpCodes.Beq, l);
 658                                         ilgen.Emit (OpCodes.Ldarg_0);
 659                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 660                                         ilgen.Emit (OpCodes.Ldarg_1);
 661                                         ilgen.Emit (OpCodes.Ldc_I4_1);
 662                                         ilgen.Emit (OpCodes.Sub);
 663                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 664                                         ilgen.Emit (OpCodes.Ldc_I4, (int)'\n');
 665                                         ilgen.Emit (OpCodes.Beq, l);
 666                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
 667                                         ilgen.MarkLabel (l);
 668
 669                                         pc++;
 670                                         break;
 671                                 }
 672                                 case RxOp.StartOfScan: {
 673                                         //if (strpos != string_start)
 674                                         //      return false;
 675                                         ilgen.Emit (OpCodes.Ldarg_1);
 676                                         ilgen.Emit (OpCodes.Ldarg_0);
 677                                         ilgen.Emit (OpCodes.Ldfld, fi_string_start);
 678                                         ilgen.Emit (OpCodes.Bne_Un, frame.label_fail);
 679                                         pc++;
 680                                         break;
 681                                 }
 682                                 case RxOp.End: {
 683                                         //if (!(strpos == string_end || (strpos == string_end - 1 && str [strpos] == '\n')))
 684                                         //      return false;
 685                                         Label l = ilgen.DefineLabel ();
 686
 687                                         ilgen.Emit (OpCodes.Ldarg_1);
 688                                         ilgen.Emit (OpCodes.Ldarg_0);
 689                                         ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 690                                         ilgen.Emit (OpCodes.Beq, l);
 691
 692                                         Label l2 = ilgen.DefineLabel ();
 693                                         ilgen.Emit (OpCodes.Ldarg_1);
 694                                         ilgen.Emit (OpCodes.Ldarg_0);
 695                                         ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 696                                         ilgen.Emit (OpCodes.Ldc_I4_1);
 697                                         ilgen.Emit (OpCodes.Sub);
 698                                         ilgen.Emit (OpCodes.Bne_Un, l2);
 699                                         ilgen.Emit (OpCodes.Ldarg_0);
 700                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 701                                         ilgen.Emit (OpCodes.Ldarg_1);
 702                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 703                                         ilgen.Emit (OpCodes.Ldc_I4, (int)'\n');
 704                                         ilgen.Emit (OpCodes.Bne_Un, l2);
 705                                         ilgen.Emit (OpCodes.Br, l);
 706                                         ilgen.MarkLabel (l2);
 707
 708                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
 709                                         ilgen.MarkLabel (l);
 710
 711                                         pc++;
 712                                         break;
 713                                 }
 714                                 case RxOp.EndOfString: {
 715                                         //if (strpos != string_end)
 716                                         //      return false;
 717                                         ilgen.Emit (OpCodes.Ldarg_1);
 718                                         ilgen.Emit (OpCodes.Ldarg_0);
 719                                         ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 720                                         ilgen.Emit (OpCodes.Bne_Un, frame.label_fail);
 721                                         pc++;
 722                                         break;
 723                                 }
 724                                 case RxOp.EndOfLine: {
 725                                         //if (!(strpos == string_end || str [strpos] == '\n'))
 726                                         //      return false;
 727                                         Label l_match = ilgen.DefineLabel ();
 728                                         ilgen.Emit (OpCodes.Ldarg_1);
 729                                         ilgen.Emit (OpCodes.Ldarg_0);
 730                                         ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 731                                         ilgen.Emit (OpCodes.Beq, l_match);
 732                                         ilgen.Emit (OpCodes.Ldarg_0);
 733                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 734                                         ilgen.Emit (OpCodes.Ldarg_1);
 735                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 736                                         ilgen.Emit (OpCodes.Ldc_I4, (int)'\n');
 737                                         ilgen.Emit (OpCodes.Beq, l_match);
 738                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
 739                                         ilgen.MarkLabel (l_match);
 740
 741                                         pc++;
 742                                         break;
 743                                 }
 744                                 case RxOp.WordBoundary:
 745                                 case RxOp.NoWordBoundary: {
 746                                         bool negate = op == RxOp.NoWordBoundary;
 747
 748                                         //if (string_end == 0)
 749                                         //      return false;
 750                                         ilgen.Emit (OpCodes.Ldarg_0);
 751                                         ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 752                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 753                                         ilgen.Emit (OpCodes.Beq, frame.label_fail);
 754
 755                                         Label l_match = ilgen.DefineLabel ();
 756
 757                                         //if (strpos == 0) {
 758                                         Label l1 = ilgen.DefineLabel ();
 759                                         ilgen.Emit (OpCodes.Ldarg_1);
 760                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 761                                         ilgen.Emit (OpCodes.Bne_Un, l1);
 762                                         //if (!IsWordChar (str [strpos])) {
 763                                         //  return false;
 764                                         ilgen.Emit (OpCodes.Ldarg_0);
 765                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 766                                         ilgen.Emit (OpCodes.Ldarg_1);
 767                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 768                                         ilgen.Emit (OpCodes.Call, GetMethod ("IsWordChar", ref mi_is_word_char));
 769                                         ilgen.Emit (negate ? OpCodes.Brtrue : OpCodes.Brfalse, frame.label_fail);
 770                                         ilgen.Emit (OpCodes.Br, l_match);
 771
 772                                         //} else if (strpos == string_end) {
 773                                         ilgen.MarkLabel (l1);
 774                                         Label l2 = ilgen.DefineLabel ();
 775                                         ilgen.Emit (OpCodes.Ldarg_1);
 776                                         ilgen.Emit (OpCodes.Ldarg_0);
 777                                         ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 778                                         ilgen.Emit (OpCodes.Bne_Un, l2);
 779                                         //if (!IsWordChar (str [strpos - 1])) {
 780                                         //  return false;
 781                                         ilgen.Emit (OpCodes.Ldarg_0);
 782                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 783                                         ilgen.Emit (OpCodes.Ldarg_1);
 784                                         ilgen.Emit (OpCodes.Ldc_I4_1);
 785                                         ilgen.Emit (OpCodes.Sub);
 786                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 787                                         ilgen.Emit (OpCodes.Call, GetMethod ("IsWordChar", ref mi_is_word_char));
 788                                         ilgen.Emit (negate ? OpCodes.Brtrue : OpCodes.Brfalse, frame.label_fail);
 789                                         ilgen.Emit (OpCodes.Br, l_match);
 790
 791                                         //} else {
 792                                         ilgen.MarkLabel (l2);
 793                                         //if (IsWordChar (str [strpos]) == IsWordChar (str [strpos - 1])) {
 794                                         //  return false;
 795                                         ilgen.Emit (OpCodes.Ldarg_0);
 796                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 797                                         ilgen.Emit (OpCodes.Ldarg_1);
 798                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 799                                         ilgen.Emit (OpCodes.Call, GetMethod ("IsWordChar", ref mi_is_word_char));
 800                                         ilgen.Emit (OpCodes.Ldarg_0);
 801                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 802                                         ilgen.Emit (OpCodes.Ldarg_1);
 803                                         ilgen.Emit (OpCodes.Ldc_I4_1);
 804                                         ilgen.Emit (OpCodes.Sub);
 805                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 806                                         ilgen.Emit (OpCodes.Call, GetMethod ("IsWordChar", ref mi_is_word_char));
 807                                         ilgen.Emit (negate ? OpCodes.Bne_Un : OpCodes.Beq, frame.label_fail);
 808                                         ilgen.Emit (OpCodes.Br, l_match);
 809
 810                                         ilgen.MarkLabel (l_match);
 811
 812                                         pc++;
 813                                         break;
 814                                 }
 815                                 case RxOp.Bitmap:
 816                                 case RxOp.UnicodeBitmap: {
 817                                         OpFlags flags = (OpFlags)op_flags [pc];
 818                                         bool negate = (flags & OpFlags.Negate) > 0;
 819                                         bool ignore = (flags & OpFlags.IgnoreCase) > 0;
 820                                         bool reverse = (flags & OpFlags.RightToLeft) > 0;
 821                                         bool unicode = (op == RxOp.UnicodeBitmap);
 822
 823                                         //if (strpos < string_end) {
 824                                         Label l1 = ilgen.DefineLabel ();
 825                                         Label l2 = ilgen.DefineLabel ();
 826                                         Label l_match = ilgen.DefineLabel ();
 827                                         if (reverse) {
 828                                                 ilgen.Emit (OpCodes.Ldarg_1);
 829                                                 ilgen.Emit (OpCodes.Ldc_I4_0);
 830                                                 ilgen.Emit (OpCodes.Ble, l1);
 831                                         } else {
 832                                                 ilgen.Emit (OpCodes.Ldarg_1);
 833                                                 ilgen.Emit (OpCodes.Ldarg_0);
 834                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 835                                                 ilgen.Emit (OpCodes.Bge, l1);
 836                                         }
 837                                         //  int c = str [strpos];
 838                                         LocalBuilder local_c = ilgen.DeclareLocal (typeof (int));
 839                                         if (ignore)
 840                                                 ilgen.Emit (OpCodes.Ldloc, local_textinfo);
 841                                         ilgen.Emit (OpCodes.Ldarg_0);
 842                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 843                                         ilgen.Emit (OpCodes.Ldarg_1);
 844                                         if (reverse) {
 845                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 846                                                 ilgen.Emit (OpCodes.Sub);
 847                                         }
 848                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
 849                                         ilgen.Emit (OpCodes.Conv_I4);
 850                                         if (ignore)
 851                                                 ilgen.Emit (OpCodes.Callvirt, typeof (TextInfo).GetMethod ("ToLower", new Type [] { typeof (char) }));
 852                                         //  c -= program [pc + 1];
 853                                         if (unicode) {
 854                                                 ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 1));
 855                                                 ilgen.Emit (OpCodes.Sub);
 856                                                 ilgen.Emit (OpCodes.Stloc, local_c);
 857                                                 length = ReadShort (program, pc + 3);
 858                                                 pc += 5;
 859                                         } else {
 860                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 1]);
 861                                                 ilgen.Emit (OpCodes.Sub);
 862                                                 ilgen.Emit (OpCodes.Stloc, local_c);
 863                                                 length =  program [pc + 2];
 864                                                 pc += 3;
 865                                         }
 866                                         //  if (c < 0 || c >= (length << 3))
 867                                         //    return false;
 868                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 869                                         ilgen.Emit (OpCodes.Ldc_I4_0);
 870                                         ilgen.Emit (OpCodes.Blt, negate ? l_match : frame.label_fail);
 871                                         ilgen.Emit (OpCodes.Ldloc, local_c);
 872                                         ilgen.Emit (OpCodes.Ldc_I4, length << 3);
 873                                         ilgen.Emit (OpCodes.Bge, negate ? l_match : frame.label_fail);
 874
 875                                         // Optimized version for small bitmaps
 876                                         if (length <= 4) {
 877                                                 uint bitmap = program [pc];
 878
 879                                                 if (length > 1)
 880                                                         bitmap |= ((uint)program [pc + 1] << 8);
 881                                                 if (length > 2)
 882                                                         bitmap |= ((uint)program [pc + 2] << 16);
 883                                                 if (length > 3)
 884                                                         bitmap |= ((uint)program [pc + 3] << 24);
 885
 886                                                 //if ((bitmap >> c) & 1)
 887                                                 ilgen.Emit (OpCodes.Ldc_I4, bitmap);
 888                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
 889                                                 ilgen.Emit (OpCodes.Shr_Un);
 890                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 891                                                 ilgen.Emit (OpCodes.And);
 892                                                 ilgen.Emit (negate ? OpCodes.Brtrue : OpCodes.Brfalse, l1);
 893                                         } else {
 894                                                 //  if ((program [pc + (c >> 3)] & (1 << (c & 0x7))) != 0) {
 895                                                 ilgen.Emit (OpCodes.Ldarg_0);
 896                                                 ilgen.Emit (OpCodes.Ldfld, fi_program);
 897                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
 898                                                 ilgen.Emit (OpCodes.Ldc_I4_3);
 899                                                 ilgen.Emit (OpCodes.Shr);
 900                                                 ilgen.Emit (OpCodes.Ldc_I4, pc);
 901                                                 ilgen.Emit (OpCodes.Add);
 902                                                 ilgen.Emit (OpCodes.Ldelem_I1);
 903                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 904                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
 905                                                 ilgen.Emit (OpCodes.Ldc_I4, 7);
 906                                                 ilgen.Emit (OpCodes.And);
 907                                                 ilgen.Emit (OpCodes.Shl);
 908                                                 ilgen.Emit (OpCodes.And);
 909                                                 ilgen.Emit (OpCodes.Ldc_I4_0);
 910                                                 ilgen.Emit (negate ? OpCodes.Bne_Un : OpCodes.Beq, l1);
 911                                         }
 912                                         ilgen.MarkLabel (l_match);
 913                                         if (!no_bump) {
 914                                                 //  strpos++ / strpos--;
 915                                                 ilgen.Emit (OpCodes.Ldarg_1);
 916                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
 917                                                 if (reverse)
 918                                                         ilgen.Emit (OpCodes.Sub);
 919                                                 else
 920                                                         ilgen.Emit (OpCodes.Add);
 921                                                 ilgen.Emit (OpCodes.Starg, 1);
 922                                         }
 923                                         //    continue;
 924                                         ilgen.Emit (OpCodes.Br, l2);
 925                                         //  }
 926                                         //}
 927                                         //return false;
 928                                         ilgen.MarkLabel (l1);
 929                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
 930
 931                                         ilgen.MarkLabel (l2);
 932
 933                                         pc += length;
 934                                         break;
 935                                 }
 936                                 case RxOp.String:
 937                                 case RxOp.UnicodeString: {
 938                                         OpFlags flags = (OpFlags)op_flags [pc];
 939                                         bool ignore = (flags & OpFlags.IgnoreCase) > 0;
 940                                         bool reverse = (flags & OpFlags.RightToLeft) > 0;
 941                                         bool unicode = (op == RxOp.UnicodeString);
 942
 943                                         if (unicode) {
 944                                                 start = pc + 3;
 945                                                 length = ReadShort (program, pc + 1);
 946                                         } else {
 947                                                 start = pc + 2;
 948                                                 length = program [pc + 1];
 949                                         }
 950                                         //if (strpos + length > string_end)
 951                                         //      return false;
 952                                         if (reverse) {
 953                                                 ilgen.Emit (OpCodes.Ldarg_1);
 954                                                 ilgen.Emit (OpCodes.Ldc_I4, length);
 955                                                 ilgen.Emit (OpCodes.Blt, frame.label_fail);
 956                                         } else {
 957                                                 ilgen.Emit (OpCodes.Ldarg_1);
 958                                                 ilgen.Emit (OpCodes.Ldc_I4, length);
 959                                                 ilgen.Emit (OpCodes.Add);
 960                                                 ilgen.Emit (OpCodes.Ldarg_0);
 961                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
 962                                                 ilgen.Emit (OpCodes.Bgt, frame.label_fail);
 963                                         }
 964
 965                                         /* Avoid unsafe code in Moonlight build */
 966 #if false && !NET_2_1
 967                                         // FIXME:
 968                                         if (reverse || unicode)
 969                                                 throw new NotImplementedException ();
 970                                         int i;
 971                                         LocalBuilder local_strptr = ilgen.DeclareLocal (typeof (char).MakePointerType ());
 972                                         // char *strptr = &str.start_char + strpos
 973                                         ilgen.Emit (OpCodes.Ldarg_0);
 974                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
 975                                         ilgen.Emit (OpCodes.Ldflda, typeof (String).GetField ("start_char", BindingFlags.Instance|BindingFlags.NonPublic));
 976                                         ilgen.Emit (OpCodes.Ldarg_1);
 977                                         ilgen.Emit (OpCodes.Ldc_I4_1);
 978                                         ilgen.Emit (OpCodes.Shl);
 979                                         ilgen.Emit (OpCodes.Add);
 980                                         ilgen.Emit (OpCodes.Stloc, local_strptr);
 981
 982                                         end = start + length;
 983                                         for (i = 0; i < length; ++i) {
 984                                                 // if (*(strptr + i) != program [start + i])
 985                                                 //   return false;
 986                                                 if (ignore)
 987                                                         ilgen.Emit (OpCodes.Ldloc, local_textinfo);
 988                                                 ilgen.Emit (OpCodes.Ldloc, local_strptr);
 989                                                 ilgen.Emit (OpCodes.Ldc_I4, i * 2);
 990                                                 ilgen.Emit (OpCodes.Add);
 991                                                 ilgen.Emit (OpCodes.Ldind_I2);
 992                                                 if (ignore)
 993                                                         ilgen.Emit (OpCodes.Callvirt, typeof (TextInfo).GetMethod ("ToLower", new Type [] { typeof (char) }));
 994                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)program [start + i]);
 995                                                 ilgen.Emit (OpCodes.Bne_Un, frame.label_fail);
 996                                         }
 997
 998                                         // strpos += length
 999                                         ilgen.Emit (OpCodes.Ldarg_1);
1000                                         ilgen.Emit (OpCodes.Ldc_I4, length);
1001                                         ilgen.Emit (OpCodes.Add);
1002                                         ilgen.Emit (OpCodes.Starg, 1);
1003
1004 #else
1005                                         // Allocate a local for 'str' to save an indirection
1006                                         LocalBuilder local_str = ilgen.DeclareLocal (typeof (string));
1007                                         ilgen.Emit (OpCodes.Ldarg_0);
1008                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
1009                                         ilgen.Emit (OpCodes.Stloc, local_str);
1010
1011                                         if (reverse) {
1012                                                 // strpos -= length;
1013                                                 ilgen.Emit (OpCodes.Ldarg_1);
1014                                                 ilgen.Emit (OpCodes.Ldc_I4, length);
1015                                                 ilgen.Emit (OpCodes.Sub);
1016                                                 ilgen.Emit (OpCodes.Starg, 1);
1017                                         }
1018
1019                                         // FIXME: Emit a loop for long strings
1020                                         end = start + (unicode ? length * 2 : length);
1021                                         while (start < end) {
1022                                                 //if (str [strpos] != program [start])
1023                                                 //      return false;
1024                                                 if (ignore)
1025                                                         ilgen.Emit (OpCodes.Ldloc, local_textinfo);
1026                                                 ilgen.Emit (OpCodes.Ldloc, local_str);
1027                                                 ilgen.Emit (OpCodes.Ldarg_1);
1028                                                 ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
1029                                                 if (ignore)
1030                                                         ilgen.Emit (OpCodes.Callvirt, typeof (TextInfo).GetMethod ("ToLower", new Type [] { typeof (char) }));
1031                                                 ilgen.Emit (OpCodes.Ldc_I4, unicode ? ReadShort (program, start) : (int)program [start]);
1032                                                 ilgen.Emit (OpCodes.Bne_Un, frame.label_fail);
1033                                                 //strpos++;
1034                                                 ilgen.Emit (OpCodes.Ldarg_1);
1035                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
1036                                                 ilgen.Emit (OpCodes.Add);
1037                                                 ilgen.Emit (OpCodes.Starg, 1);
1038
1039                                                 if (unicode)
1040                                                         start += 2;
1041                                                 else
1042                                                         start ++;
1043                                         }
1044
1045                                         if (reverse) {
1046                                                 // strpos -= length;
1047                                                 ilgen.Emit (OpCodes.Ldarg_1);
1048                                                 ilgen.Emit (OpCodes.Ldc_I4, length);
1049                                                 ilgen.Emit (OpCodes.Sub);
1050                                                 ilgen.Emit (OpCodes.Starg, 1);
1051                                         }
1052 #endif
1053
1054                                         pc = end;
1055                                         break;
1056                                 }
1057                                 case RxOp.OpenGroup: {
1058                                         //Open (program [pc + 1] | (program [pc + 2] << 8), strpos);
1059                                         int group_id = ReadShort (program, pc + 1);
1060                                         ilgen.Emit (OpCodes.Ldarg_0);
1061                                         ilgen.Emit (OpCodes.Ldc_I4, group_id);
1062                                         ilgen.Emit (OpCodes.Ldarg_1);
1063                                         ilgen.Emit (OpCodes.Call, GetMethod ("Open", ref mi_open));
1064
1065                                         pc += 3;
1066                                         break;
1067                                 }
1068                                 case RxOp.CloseGroup: {
1069                                         //Close (program [pc + 1] | (program [pc + 2] << 8), strpos);
1070                                         int group_id = ReadShort (program, pc + 1);
1071                                         ilgen.Emit (OpCodes.Ldarg_0);
1072                                         ilgen.Emit (OpCodes.Ldc_I4, group_id);
1073                                         ilgen.Emit (OpCodes.Ldarg_1);
1074                                         ilgen.Emit (OpCodes.Call, GetMethod ("Close", ref mi_close));
1075
1076                                         pc += 3;
1077                                         break;
1078                                 }
1079                                 case RxOp.Jump: {
1080                                         int target_pc = pc + ReadShort (program, pc + 1);
1081                                         if (target_pc > end_pc)
1082                                                 /*
1083                                                  * This breaks the our code generation logic, see
1084                                                  * https://bugzilla.novell.com/show_bug.cgi?id=466151
1085                                                  * for an example.
1086                                                  */
1087                                                 return null;
1088                                         if (trace_compile)
1089                                                 Console.WriteLine ("\tjump target: {0}", target_pc);
1090                                         if (labels == null)
1091                                                 labels = new Dictionary <int, Label> ();
1092                                         Label l = CreateLabelForPC (ilgen, target_pc);
1093                                         ilgen.Emit (OpCodes.Br, l);
1094                                         pc += 3;
1095                                         break;
1096                                 }
1097                                 case RxOp.Test: {
1098                                         int target1 = pc + ReadShort (program, pc + 1);
1099                                         int target2 = pc + ReadShort (program, pc + 3);
1100
1101                                         if (trace_compile)
1102                                                 Console.WriteLine ("\temitting <test_expr>");
1103
1104                                         //  old_stros = strpos;
1105                                         LocalBuilder local_old_strpos = ilgen.DeclareLocal (typeof (int));
1106                                         ilgen.Emit (OpCodes.Ldarg_1);
1107                                         ilgen.Emit (OpCodes.Stloc, local_old_strpos);
1108
1109                                         Frame new_frame = new Frame (ilgen);
1110                                         m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc + 5, target1 < target2 ? target1 : target2, false, false, out pc);
1111                                         if (m == null)
1112                                                 return null;
1113
1114                                         if (trace_compile) {
1115                                                 Console.WriteLine ("\temitted <test_expr>");
1116                                                 Console.WriteLine ("\ttarget1 = {0}", target1);
1117                                                 Console.WriteLine ("\ttarget2 = {0}", target2);
1118                                         }
1119
1120                                         Label l1 = CreateLabelForPC (ilgen, target1);
1121                                         Label l2 = CreateLabelForPC (ilgen, target2);
1122
1123                                         // Pass
1124                                         ilgen.MarkLabel (new_frame.label_pass);
1125                                         //  strpos = old_strpos;
1126                                         ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
1127                                         ilgen.Emit (OpCodes.Starg, 1);
1128                                         ilgen.Emit (OpCodes.Br, l1);
1129
1130                                         // Fail
1131                                         ilgen.MarkLabel (new_frame.label_fail);
1132                                         //  strpos = old_strpos;
1133                                         ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
1134                                         ilgen.Emit (OpCodes.Starg, 1);
1135                                         ilgen.Emit (OpCodes.Br, l2);
1136
1137                                         // Continue at pc, which should equal to target1
1138                                         break;
1139                                 }
1140                                 case RxOp.SubExpression: {
1141                                         int target = pc + ReadShort (program, pc + 1);
1142
1143                                         if (trace_compile)
1144                                                 Console.WriteLine ("\temitting <sub_expr>");
1145
1146                                         //  old_stros = strpos;
1147                                         LocalBuilder local_old_strpos = ilgen.DeclareLocal (typeof (int));
1148                                         ilgen.Emit (OpCodes.Ldarg_1);
1149                                         ilgen.Emit (OpCodes.Stloc, local_old_strpos);
1150
1151                                         Frame new_frame = new Frame (ilgen);
1152                                         m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc + 3, target, false, false, out pc);
1153                                         if (m == null)
1154                                                 return null;
1155
1156                                         if (trace_compile) {
1157                                                 Console.WriteLine ("\temitted <sub_expr>");
1158                                                 Console.WriteLine ("\ttarget = {0}", target);
1159                                         }
1160
1161                                         Label l1 = CreateLabelForPC (ilgen, target);
1162
1163                                         // Pass
1164                                         ilgen.MarkLabel (new_frame.label_pass);
1165                                         ilgen.Emit (OpCodes.Br, l1);
1166
1167                                         // Fail
1168                                         ilgen.MarkLabel (new_frame.label_fail);
1169                                         //  strpos = old_strpos;
1170                                         ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
1171                                         ilgen.Emit (OpCodes.Starg, 1);
1172                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
1173
1174                                         // Continue at pc, which should equal to target
1175                                         break;
1176                                 }
1177                                 case RxOp.TestCharGroup: {
1178                                         int char_group_end = pc + ReadShort (program, pc + 1);
1179                                         pc += 3;
1180
1181                                         Label label_match = ilgen.DefineLabel ();
1182
1183                                         /* Determine the negate/reverse flags by examining the first op */
1184                                         OpFlags flags = (OpFlags)op_flags [pc];
1185
1186                                         /* Determine whenever this is a negated character class */
1187                                         /* If it is, then the conditions are ANDed together, not ORed */
1188                                         bool revert = (flags & OpFlags.Negate) > 0;
1189                                         bool reverse = (flags & OpFlags.RightToLeft) > 0;
1190
1191                                         /*
1192                                          * Generate code for all the matching ops in the group
1193                                          */
1194                                         while (pc < char_group_end) {
1195                                                 Frame new_frame = new Frame (ilgen);
1196                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc, Int32.MaxValue, true, true, out pc);
1197                                                 if (m == null)
1198                                                         return null;
1199
1200                                                 if (!revert) {
1201                                                         // Pass
1202                                                         ilgen.MarkLabel (new_frame.label_pass);
1203                                                         ilgen.Emit (OpCodes.Br, label_match);
1204
1205                                                         // Fail
1206                                                         // Just fall through to the next test
1207                                                         ilgen.MarkLabel (new_frame.label_fail);
1208                                                 } else {
1209                                                         // Pass
1210                                                         // Just fall through to the next test
1211                                                         ilgen.MarkLabel (new_frame.label_pass);
1212                                                         Label l2 = ilgen.DefineLabel ();
1213                                                         ilgen.Emit (OpCodes.Br, l2);
1214
1215                                                         // Fail
1216                                                         // Fail completely
1217                                                         ilgen.MarkLabel (new_frame.label_fail);
1218                                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
1219
1220                                                         ilgen.MarkLabel (l2);
1221                                                 }
1222                                         }
1223
1224                                         if (revert) {
1225                                                 /* Success */
1226                                                 ilgen.Emit (OpCodes.Br, label_match);
1227                                         } else {
1228                                                 // If we reached here, all the matching ops have failed
1229                                                 ilgen.Emit (OpCodes.Br, frame.label_fail);
1230                                         }
1231
1232                                         ilgen.MarkLabel (label_match);
1233
1234                                         //  strpos++ / strpos--;
1235                                         ilgen.Emit (OpCodes.Ldarg_1);
1236                                         ilgen.Emit (OpCodes.Ldc_I4_1);
1237                                         if (reverse)
1238                                                 ilgen.Emit (OpCodes.Sub);
1239                                         else
1240                                                 ilgen.Emit (OpCodes.Add);
1241                                         ilgen.Emit (OpCodes.Starg, 1);
1242
1243                                         break;
1244                                 }
1245                                 case RxOp.FastRepeat:
1246                                 case RxOp.FastRepeatLazy: {
1247                                         /*
1248                                          * A FastRepeat is a simplified version of Repeat which does
1249                                          * not contain another repeat inside, so backtracking is
1250                                          * easier.
1251                                          * FIXME: Implement faster backtracking versions for
1252                                          * simple inner exceptions like chars/strings.
1253                                          */
1254                                         bool lazy = program [pc] == (byte)RxOp.FastRepeatLazy;
1255                                         int tail = pc + ReadShort (program, pc + 1);
1256                                         start = ReadInt (program, pc + 3);
1257                                         end = ReadInt (program, pc + 7);
1258                                         //Console.WriteLine ("min: {0}, max: {1} tail: {2}", start, end, tail);
1259
1260                                         //  deep = null;
1261                                         ilgen.Emit (OpCodes.Ldarg_0);
1262                                         ilgen.Emit (OpCodes.Ldnull);
1263                                         ilgen.Emit (OpCodes.Stfld, fi_deep);
1264
1265                                         LocalBuilder local_length = ilgen.DeclareLocal (typeof (int));
1266
1267                                         ilgen.Emit (OpCodes.Ldc_I4_0);
1268                                         ilgen.Emit (OpCodes.Stloc, local_length);
1269
1270                                         LocalBuilder local_old_strpos = ilgen.DeclareLocal (typeof (int));
1271
1272                                         // First match at least 'start' items
1273                                         if (start > 0) {
1274                                                 //for (length = 0; length < start; ++length) {
1275                                                 Label l_loop_footer = ilgen.DefineLabel ();
1276                                                 ilgen.Emit (OpCodes.Br, l_loop_footer);
1277                                                 Label l_loop_body = ilgen.DefineLabel ();
1278                                                 ilgen.MarkLabel (l_loop_body);
1279
1280                                                 // int old_strpos = strpos;
1281                                                 ilgen.Emit (OpCodes.Ldarg_1);
1282                                                 ilgen.Emit (OpCodes.Stloc, local_old_strpos);
1283
1284                                                 // if (!EvalByteCode (pc + 11, strpos, ref res))
1285                                                 Frame new_frame = new Frame (ilgen);
1286                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc + 11, tail, false, false, out out_pc);
1287                                                 if (m == null)
1288                                                         return null;
1289
1290                                                 // Fail
1291                                                 // return false;
1292                                                 ilgen.MarkLabel (new_frame.label_fail);
1293                                                 ilgen.Emit (OpCodes.Br, frame.label_fail);
1294
1295                                                 // Pass
1296                                                 ilgen.MarkLabel (new_frame.label_pass);
1297                                                 // length++
1298                                                 ilgen.Emit (OpCodes.Ldloc, local_length);
1299                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
1300                                                 ilgen.Emit (OpCodes.Add);
1301                                                 ilgen.Emit (OpCodes.Stloc, local_length);
1302                                                 // Loop footer
1303                                                 ilgen.MarkLabel (l_loop_footer);
1304                                                 ilgen.Emit (OpCodes.Ldloc, local_length);
1305                                                 ilgen.Emit (OpCodes.Ldc_I4, start);
1306                                                 ilgen.Emit (OpCodes.Blt, l_loop_body);
1307                                         }
1308
1309                                         if (lazy) {
1310                                                 Label l_loop_footer = ilgen.DefineLabel ();
1311                                                 //while (true) {
1312                                                 ilgen.Emit (OpCodes.Br, l_loop_footer);
1313                                                 Label l_loop_body = ilgen.DefineLabel ();
1314                                                 ilgen.MarkLabel (l_loop_body);
1315                                                 // Match the tail
1316                                                 //  int cp = Checkpoint ();
1317                                                 LocalBuilder local_cp = ilgen.DeclareLocal (typeof (int));
1318                                                 ilgen.Emit (OpCodes.Ldarg_0);
1319                                                 ilgen.Emit (OpCodes.Call, GetMethod ("Checkpoint", ref mi_checkpoint));
1320                                                 ilgen.Emit (OpCodes.Stloc, local_cp);
1321
1322                                                 // int old_strpos = strpos;
1323                                                 ilgen.Emit (OpCodes.Ldarg_1);
1324                                                 ilgen.Emit (OpCodes.Stloc, local_old_strpos);
1325
1326                                                 //  if (EvalByteCode (tail, strpos, ref res)) {
1327                                                 Frame new_frame = new Frame (ilgen);
1328                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, tail, end_pc, false, false, out out_pc);
1329                                                 if (m == null)
1330                                                         return null;
1331
1332                                                 // Success:
1333                                                 ilgen.MarkLabel (new_frame.label_pass);
1334                                                 //    return true;
1335                                                 ilgen.Emit (OpCodes.Br, frame.label_pass);
1336
1337                                                 // Fail:
1338                                                 ilgen.MarkLabel (new_frame.label_fail);
1339                                                 //  Backtrack (cp);
1340                                                 ilgen.Emit (OpCodes.Ldarg_0);
1341                                                 ilgen.Emit (OpCodes.Ldloc, local_cp);
1342                                                 ilgen.Emit (OpCodes.Call, GetMethod ("Backtrack", ref mi_backtrack));
1343                                                 // strpos = old_strpos;
1344                                                 ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
1345                                                 ilgen.Emit (OpCodes.Starg, 1);
1346
1347                                                 //if (length >= end)
1348                                                 //  return false;
1349                                                 ilgen.Emit (OpCodes.Ldloc, local_length);
1350                                                 ilgen.Emit (OpCodes.Ldc_I4, end);
1351                                                 ilgen.Emit (OpCodes.Bge, frame.label_fail);
1352
1353                                                 // Match an item
1354                                                 //if (!EvalByteCode (pc + 11, strpos, ref res))
1355                                                 new_frame = new Frame (ilgen);
1356                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc + 11, tail, false, false, out out_pc);
1357                                                 if (m == null)
1358                                                         return null;
1359
1360                                                 // Success:
1361                                                 ilgen.MarkLabel (new_frame.label_pass);
1362                                                 // length ++;
1363                                                 ilgen.Emit (OpCodes.Ldloc, local_length);
1364                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
1365                                                 ilgen.Emit (OpCodes.Add);
1366                                                 ilgen.Emit (OpCodes.Stloc, local_length);
1367                                                 ilgen.Emit (OpCodes.Br, l_loop_body);
1368
1369                                                 // Fail:
1370                                                 ilgen.MarkLabel (new_frame.label_fail);
1371                                                 // return false;
1372                                                 ilgen.Emit (OpCodes.Br, frame.label_fail);
1373
1374                                                 // Loop footer
1375                                                 ilgen.MarkLabel (l_loop_footer);
1376                                                 ilgen.Emit (OpCodes.Br, l_loop_body);
1377                                         } else {
1378                                                 // Then match as many items as possible, recording
1379                                                 // backtracking information
1380
1381                                                 //int old_stack_size = stack.Count;
1382                                                 LocalBuilder local_old_stack_size = ilgen.DeclareLocal (typeof (int));
1383                                                 ilgen.Emit (OpCodes.Ldarg_0);
1384                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1385                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "get_Count", ref mi_stack_get_count));
1386                                                 ilgen.Emit (OpCodes.Stloc, local_old_stack_size);
1387                                                 //while (length < end) {
1388                                                 Label l_loop_footer = ilgen.DefineLabel ();
1389                                                 ilgen.Emit (OpCodes.Br, l_loop_footer);
1390                                                 Label l_loop_body = ilgen.DefineLabel ();
1391                                                 ilgen.MarkLabel (l_loop_body);
1392                                                 //  int cp = Checkpoint ();
1393                                                 LocalBuilder local_cp = ilgen.DeclareLocal (typeof (int));
1394                                                 ilgen.Emit (OpCodes.Ldarg_0);
1395                                                 ilgen.Emit (OpCodes.Call, GetMethod ("Checkpoint", ref mi_checkpoint));
1396                                                 ilgen.Emit (OpCodes.Stloc, local_cp);
1397
1398                                                 // int old_strpos = strpos;
1399                                                 ilgen.Emit (OpCodes.Ldarg_1);
1400                                                 ilgen.Emit (OpCodes.Stloc, local_old_strpos);
1401
1402                                                 //  if (!EvalByteCode (pc + 11, strpos, ref res)) {
1403                                                 Frame new_frame = new Frame (ilgen);
1404                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, pc + 11, tail, false, false, out out_pc);
1405                                                 if (m == null)
1406                                                         return null;
1407
1408                                                 // Fail:
1409                                                 ilgen.MarkLabel (new_frame.label_fail);
1410                                                 // strpos = old_strpos
1411                                                 ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
1412                                                 ilgen.Emit (OpCodes.Starg, 1);
1413                                                 //    Backtrack (cp);
1414                                                 ilgen.Emit (OpCodes.Ldarg_0);
1415                                                 ilgen.Emit (OpCodes.Ldloc, local_cp);
1416                                                 ilgen.Emit (OpCodes.Call, GetMethod ("Backtrack", ref mi_backtrack));
1417
1418                                                 //    break;
1419                                                 Label l_after_loop = ilgen.DefineLabel ();
1420                                                 ilgen.Emit (OpCodes.Br, l_after_loop);
1421
1422                                                 // Success:
1423                                                 ilgen.MarkLabel (new_frame.label_pass);
1424
1425                                                 //stack.Push (cp);
1426                                                 ilgen.Emit (OpCodes.Ldarg_0);
1427                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1428                                                 ilgen.Emit (OpCodes.Ldloc, local_cp);
1429                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "Push", ref mi_stack_push));
1430                                                 //stack.Push (strpos);
1431                                                 ilgen.Emit (OpCodes.Ldarg_0);
1432                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1433                                                 ilgen.Emit (OpCodes.Ldloc, local_old_strpos);
1434                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "Push", ref mi_stack_push));
1435                                                 // length++
1436                                                 ilgen.Emit (OpCodes.Ldloc, local_length);
1437                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
1438                                                 ilgen.Emit (OpCodes.Add);
1439                                                 ilgen.Emit (OpCodes.Stloc, local_length);
1440                                                 // Loop footer
1441                                                 ilgen.MarkLabel (l_loop_footer);
1442                                                 ilgen.Emit (OpCodes.Ldloc, local_length);
1443                                                 ilgen.Emit (OpCodes.Ldc_I4, end);
1444                                                 ilgen.Emit (OpCodes.Blt, l_loop_body);
1445
1446                                                 ilgen.MarkLabel (l_after_loop);
1447
1448                                                 // Then, match the tail, backtracking as necessary.
1449
1450                                                 //while (true) {
1451                                                 l_loop_footer = ilgen.DefineLabel ();
1452                                                 ilgen.Emit (OpCodes.Br, l_loop_footer);
1453                                                 l_loop_body = ilgen.DefineLabel ();
1454                                                 ilgen.MarkLabel (l_loop_body);
1455
1456                                                 if (RxInterpreter.trace_rx) {
1457                                                         ilgen.Emit (OpCodes.Ldstr, "matching tail at: {0}");
1458                                                         ilgen.Emit (OpCodes.Ldarg_1);
1459                                                         ilgen.Emit (OpCodes.Box, typeof (int));
1460                                                         ilgen.Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type [] { typeof (string), typeof (object) }));
1461                                                 }
1462
1463                                                 //  if (EvalByteCode (tail, strpos, ref res)) {
1464                                                 new_frame = new Frame (ilgen);
1465                                                 m = EmitEvalMethodBody (m, ilgen, new_frame, program, tail, end_pc, false, false, out out_pc);
1466                                                 if (m == null)
1467                                                         return null;
1468
1469                                                 // Success:
1470                                                 ilgen.MarkLabel (new_frame.label_pass);
1471
1472                                                 if (RxInterpreter.trace_rx) {
1473                                                         ilgen.Emit (OpCodes.Ldstr, "tail matched at: {0}");
1474                                                         ilgen.Emit (OpCodes.Ldarg_1);
1475                                                         ilgen.Emit (OpCodes.Box, typeof (int));
1476                                                         ilgen.Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type [] { typeof (string), typeof (object) }));
1477                                                 }
1478
1479                                                 //      stack.Count = old_stack_size;
1480                                                 ilgen.Emit (OpCodes.Ldarg_0);
1481                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1482                                                 ilgen.Emit (OpCodes.Ldloc, local_old_stack_size);
1483                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "set_Count", ref mi_stack_set_count));
1484                                                 //  return true;
1485                                                 ilgen.Emit (OpCodes.Br, frame.label_pass);
1486
1487                                                 // Fail:
1488                                                 ilgen.MarkLabel (new_frame.label_fail);
1489
1490                                                 if (RxInterpreter.trace_rx) {
1491                                                         ilgen.Emit (OpCodes.Ldstr, "tail failed to match at: {0}");
1492                                                         ilgen.Emit (OpCodes.Ldarg_1);
1493                                                         ilgen.Emit (OpCodes.Box, typeof (int));
1494                                                         ilgen.Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type [] { typeof (string), typeof (object) }));
1495                                                 }
1496
1497                                                 //  if (stack.Count == old_stack_size)
1498                                                 //              return false;
1499                                                 ilgen.Emit (OpCodes.Ldarg_0);
1500                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1501                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "get_Count", ref mi_stack_get_count));
1502                                                 ilgen.Emit (OpCodes.Ldloc, local_old_stack_size);
1503                                                 ilgen.Emit (OpCodes.Beq, frame.label_fail);
1504
1505                                                 // Backtrack
1506                                                 //strpos = stack.Pop ();
1507                                                 ilgen.Emit (OpCodes.Ldarg_0);
1508                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1509                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "Pop", ref mi_stack_pop));
1510                                                 ilgen.Emit (OpCodes.Starg, 1);
1511                                                 //Backtrack (stack.Pop ());
1512                                                 ilgen.Emit (OpCodes.Ldarg_0);
1513                                                 ilgen.Emit (OpCodes.Ldarg_0);
1514                                                 ilgen.Emit (OpCodes.Ldflda, fi_stack);
1515                                                 ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter.IntStack), "Pop", ref mi_stack_pop));
1516                                                 ilgen.Emit (OpCodes.Call, GetMethod ("Backtrack", ref mi_backtrack));
1517
1518                                                 if (RxInterpreter.trace_rx) {
1519                                                         //Console.WriteLine ("backtracking to: {0}", strpos);
1520                                                         ilgen.Emit (OpCodes.Ldstr, "backtracking to: {0}");
1521                                                         ilgen.Emit (OpCodes.Ldarg_1);
1522                                                         ilgen.Emit (OpCodes.Box, typeof (int));
1523                                                         ilgen.Emit (OpCodes.Call, typeof (Console).GetMethod ("WriteLine", new Type [] { typeof (string), typeof (object) }));
1524                                                 }
1525
1526                                                 // Loop footer
1527                                                 ilgen.MarkLabel (l_loop_footer);
1528                                                 ilgen.Emit (OpCodes.Br, l_loop_body);
1529                                         }
1530
1531                                         // We already processed the tail
1532                                         pc = out_pc;
1533                                         goto End;
1534                                 }
1535
1536                                 case RxOp.CategoryAny:
1537                                 case RxOp.CategoryAnySingleline:
1538                                 case RxOp.CategoryWord:
1539                                 case RxOp.CategoryDigit:
1540                                 case RxOp.CategoryWhiteSpace:
1541                                 case RxOp.CategoryEcmaWord:
1542                                 case RxOp.CategoryEcmaWhiteSpace:
1543                                 case RxOp.CategoryUnicodeSpecials:
1544                                 case RxOp.CategoryUnicode: {
1545                                         OpFlags flags = (OpFlags)op_flags [pc];
1546                                         bool negate = (flags & OpFlags.Negate) > 0;
1547                                         bool reverse = (flags & OpFlags.RightToLeft) > 0;
1548
1549                                         //if (strpos < string_end) {
1550                                         Label l_nomatch = ilgen.DefineLabel ();
1551                                         if (reverse) {
1552                                                 ilgen.Emit (OpCodes.Ldarg_1);
1553                                                 ilgen.Emit (OpCodes.Ldc_I4_0);
1554                                                 ilgen.Emit (OpCodes.Ble, l_nomatch);
1555                                         } else {
1556                                                 ilgen.Emit (OpCodes.Ldarg_1);
1557                                                 ilgen.Emit (OpCodes.Ldarg_0);
1558                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
1559                                                 ilgen.Emit (OpCodes.Bge, l_nomatch);
1560                                         }
1561
1562                                         //  int c = str [strpos];
1563                                         LocalBuilder local_c = ilgen.DeclareLocal (typeof (char));
1564                                         ilgen.Emit (OpCodes.Ldarg_0);
1565                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
1566                                         ilgen.Emit (OpCodes.Ldarg_1);
1567                                         if (reverse) {
1568                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
1569                                                 ilgen.Emit (OpCodes.Sub);
1570                                         }
1571                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
1572                                         ilgen.Emit (OpCodes.Stloc, local_c);
1573
1574                                         Label l_match = ilgen.DefineLabel ();
1575
1576                                         Label l_true, l_false;
1577
1578                                         l_true = negate ? l_nomatch : l_match;
1579                                         l_false = negate ? l_match : l_nomatch;
1580
1581                                         switch (op) {
1582                                         case RxOp.CategoryAny:
1583                                                 // if (str [strpos] != '\n') {
1584                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1585                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\n');
1586                                                 ilgen.Emit (OpCodes.Bne_Un, l_true);
1587                                                 break;
1588                                         case RxOp.CategoryAnySingleline:
1589                                                 ilgen.Emit (OpCodes.Br, l_true);
1590                                                 break;
1591                                         case RxOp.CategoryWord:
1592                                                 //  if (Char.IsLetterOrDigit (c) || Char.GetUnicodeCategory (c) == UnicodeCategory.ConnectorPunctuation) {
1593                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1594                                                 ilgen.Emit (OpCodes.Call, typeof (Char).GetMethod ("IsLetterOrDigit", new Type [] { typeof (char) }));
1595                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1596                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1597                                                 ilgen.Emit (OpCodes.Call, typeof (Char).GetMethod ("GetUnicodeCategory", new Type [] { typeof (char) }));
1598                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)UnicodeCategory.ConnectorPunctuation);
1599                                                 ilgen.Emit (OpCodes.Beq, l_true);
1600                                                 break;
1601                                         case RxOp.CategoryDigit:
1602                                                 // if (Char.IsDigit (c)) {
1603                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1604                                                 ilgen.Emit (OpCodes.Call, typeof (Char).GetMethod ("IsDigit", new Type [] { typeof (char) }));
1605                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1606                                                 break;
1607                                         case RxOp.CategoryWhiteSpace:
1608                                                 // if (Char.IsWhiteSpace (c)) {
1609                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1610                                                 ilgen.Emit (OpCodes.Call, typeof (Char).GetMethod ("IsWhiteSpace", new Type [] { typeof (char) }));
1611                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1612                                                 break;
1613                                         case RxOp.CategoryEcmaWord:
1614                                                 // if ('a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || '0' <= c && c <= '9' || c == '_') {
1615                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1616                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'a' - 1);
1617                                                 ilgen.Emit (OpCodes.Cgt);
1618                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1619                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'z' + 1);
1620                                                 ilgen.Emit (OpCodes.Clt);
1621                                                 ilgen.Emit (OpCodes.And);
1622                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1623
1624                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1625                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'A' - 1);
1626                                                 ilgen.Emit (OpCodes.Cgt);
1627                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1628                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'Z' + 1);
1629                                                 ilgen.Emit (OpCodes.Clt);
1630                                                 ilgen.Emit (OpCodes.And);
1631                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1632
1633                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1634                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'0' - 1);
1635                                                 ilgen.Emit (OpCodes.Cgt);
1636                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1637                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'9' + 1);
1638                                                 ilgen.Emit (OpCodes.Clt);
1639                                                 ilgen.Emit (OpCodes.And);
1640                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1641
1642                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1643                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'_');
1644                                                 ilgen.Emit (OpCodes.Beq, l_true);
1645                                                 break;
1646                                         case RxOp.CategoryEcmaWhiteSpace:
1647                                                 // if (c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v') {
1648                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1649                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)' ');
1650                                                 ilgen.Emit (OpCodes.Beq, l_true);
1651                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1652                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\t');
1653                                                 ilgen.Emit (OpCodes.Beq, l_true);
1654                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1655                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\n');
1656                                                 ilgen.Emit (OpCodes.Beq, l_true);
1657                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1658                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\r');
1659                                                 ilgen.Emit (OpCodes.Beq, l_true);
1660                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1661                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\f');
1662                                                 ilgen.Emit (OpCodes.Beq, l_true);
1663                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1664                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\v');
1665                                                 ilgen.Emit (OpCodes.Beq, l_true);
1666                                                 break;
1667                                         case RxOp.CategoryUnicodeSpecials:
1668                                                 // if ('\uFEFF' <= c && c <= '\uFEFF' || '\uFFF0' <= c && c <= '\uFFFD') {
1669                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1670                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\uFEFF' - 1);
1671                                                 ilgen.Emit (OpCodes.Cgt);
1672                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1673                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\uFEFF' + 1);
1674                                                 ilgen.Emit (OpCodes.Clt);
1675                                                 ilgen.Emit (OpCodes.And);
1676                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1677
1678                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1679                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\uFFF0' - 1);
1680                                                 ilgen.Emit (OpCodes.Cgt);
1681                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1682                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)'\uFFFD' + 1);
1683                                                 ilgen.Emit (OpCodes.Clt);
1684                                                 ilgen.Emit (OpCodes.And);
1685                                                 ilgen.Emit (OpCodes.Brtrue, l_true);
1686                                                 break;
1687                                         case RxOp.CategoryUnicode:
1688                                                 // if (Char.GetUnicodeCategory (c) == (UnicodeCategory)program [pc + 1]) {
1689                                                 ilgen.Emit (OpCodes.Ldloc, local_c);
1690                                                 ilgen.Emit (OpCodes.Call, typeof (Char).GetMethod ("GetUnicodeCategory", new Type [] { typeof (char) }));
1691                                                 ilgen.Emit (OpCodes.Ldc_I4, (int)program [pc + 1]);
1692                                                 ilgen.Emit (OpCodes.Beq, l_true);
1693                                                 break;
1694                                         }
1695
1696                                         ilgen.Emit (OpCodes.Br, l_false);
1697
1698                                         ilgen.MarkLabel (l_match);
1699
1700                                         //    strpos++;
1701                                         if (!no_bump) {
1702                                                 ilgen.Emit (OpCodes.Ldarg_1);
1703                                                 ilgen.Emit (OpCodes.Ldc_I4_1);
1704                                                 if (reverse)
1705                                                         ilgen.Emit (OpCodes.Sub);
1706                                                 else
1707                                                         ilgen.Emit (OpCodes.Add);
1708                                                 ilgen.Emit (OpCodes.Starg, 1);
1709                                         }
1710                                         //  }
1711                                         Label l2 = ilgen.DefineLabel ();
1712                                         ilgen.Emit (OpCodes.Br, l2);
1713                                         //}
1714                                         ilgen.MarkLabel (l_nomatch);
1715                                         //return false;
1716                                         ilgen.Emit (OpCodes.Br, frame.label_fail);
1717
1718                                         ilgen.MarkLabel (l2);
1719
1720                                         if (op == RxOp.CategoryUnicode)
1721                                                 pc += 2;
1722                                         else
1723                                                 pc++;
1724                                         break;
1725                                 }
1726                                 case RxOp.Reference: {
1727                                         OpFlags flags = (OpFlags)op_flags [pc];
1728                                         bool ignore = (flags & OpFlags.IgnoreCase) > 0;
1729                                         bool reverse = (flags & OpFlags.RightToLeft) > 0;
1730
1731                                         //length = GetLastDefined (program [pc + 1] | ((int)program [pc + 2] << 8));
1732                                         LocalBuilder loc_length = ilgen.DeclareLocal (typeof (int));
1733                                         ilgen.Emit (OpCodes.Ldarg_0);
1734                                         ilgen.Emit (OpCodes.Ldc_I4, ReadShort (program, pc + 1));
1735                                         ilgen.Emit (OpCodes.Call, GetMethod (typeof (RxInterpreter), "GetLastDefined", ref mi_get_last_defined));
1736                                         ilgen.Emit (OpCodes.Stloc, loc_length);
1737                                         //if (length < 0)
1738                                         //  return false;
1739                                         ilgen.Emit (OpCodes.Ldloc, loc_length);
1740                                         ilgen.Emit (OpCodes.Ldc_I4_0);
1741                                         ilgen.Emit (OpCodes.Blt, frame.label_fail);
1742                                         //start = marks [length].Index;
1743                                         LocalBuilder loc_start = ilgen.DeclareLocal (typeof (int));
1744                                         ilgen.Emit (OpCodes.Ldarg_0);
1745                                         ilgen.Emit (OpCodes.Ldfld, fi_marks);
1746                                         ilgen.Emit (OpCodes.Ldloc, loc_length);
1747                                         ilgen.Emit (OpCodes.Ldelema, typeof (Mark));
1748                                         ilgen.Emit (OpCodes.Call, GetMethod (typeof (Mark), "get_Index", ref mi_mark_get_index));
1749                                         ilgen.Emit (OpCodes.Stloc, loc_start);
1750                                         // length = marks [length].Length;
1751                                         ilgen.Emit (OpCodes.Ldarg_0);
1752                                         ilgen.Emit (OpCodes.Ldfld, fi_marks);
1753                                         ilgen.Emit (OpCodes.Ldloc, loc_length);
1754                                         ilgen.Emit (OpCodes.Ldelema, typeof (Mark));
1755                                         ilgen.Emit (OpCodes.Call, GetMethod (typeof (Mark), "get_Length", ref mi_mark_get_length));
1756                                         ilgen.Emit (OpCodes.Stloc, loc_length);
1757                                         if (reverse) {
1758                                                 //ptr -= length;
1759                                                 ilgen.Emit (OpCodes.Ldarg_1);
1760                                                 ilgen.Emit (OpCodes.Ldloc, loc_length);
1761                                                 ilgen.Emit (OpCodes.Sub);
1762                                                 ilgen.Emit (OpCodes.Starg, 1);
1763                                                 //if (ptr < 0)
1764                                                 //goto Fail;
1765                                                 ilgen.Emit (OpCodes.Ldarg_1);
1766                                                 ilgen.Emit (OpCodes.Ldc_I4_0);
1767                                                 ilgen.Emit (OpCodes.Blt, frame.label_fail);
1768                                         } else {
1769                                                 //if (strpos + length > string_end)
1770                                                 //  return false;
1771                                                 ilgen.Emit (OpCodes.Ldarg_1);
1772                                                 ilgen.Emit (OpCodes.Ldloc, loc_length);
1773                                                 ilgen.Emit (OpCodes.Add);
1774                                                 ilgen.Emit (OpCodes.Ldarg_0);
1775                                                 ilgen.Emit (OpCodes.Ldfld, fi_string_end);
1776                                                 ilgen.Emit (OpCodes.Bgt, frame.label_fail);
1777                                         }
1778
1779                                         LocalBuilder local_str = ilgen.DeclareLocal (typeof (string));
1780                                         ilgen.Emit (OpCodes.Ldarg_0);
1781                                         ilgen.Emit (OpCodes.Ldfld, fi_str);
1782                                         ilgen.Emit (OpCodes.Stloc, local_str);
1783
1784                                         // end = start + length;
1785                                         LocalBuilder loc_end = ilgen.DeclareLocal (typeof (int));
1786                                         ilgen.Emit (OpCodes.Ldloc, loc_start);
1787                                         ilgen.Emit (OpCodes.Ldloc, loc_length);
1788                                         ilgen.Emit (OpCodes.Add);
1789                                         ilgen.Emit (OpCodes.Stloc, loc_end);
1790                                         //for (; start < end; ++start) {
1791                                         Label l_loop_footer = ilgen.DefineLabel ();
1792                                         ilgen.Emit (OpCodes.Br, l_loop_footer);
1793                                         Label l_loop_body = ilgen.DefineLabel ();
1794                                         ilgen.MarkLabel (l_loop_body);
1795                                         //if (str [strpos] != str [start])
1796                                         //return false;
1797                                         if (ignore)
1798                                                 ilgen.Emit (OpCodes.Ldloc, local_textinfo);
1799                                         ilgen.Emit (OpCodes.Ldloc, local_str);
1800                                         ilgen.Emit (OpCodes.Ldarg_1);
1801                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
1802                                         if (ignore)
1803                                                 ilgen.Emit (OpCodes.Callvirt, typeof (TextInfo).GetMethod ("ToLower", new Type [] { typeof (char) }));
1804                                         if (ignore)
1805                                                 ilgen.Emit (OpCodes.Ldloc, local_textinfo);
1806                                         ilgen.Emit (OpCodes.Ldloc, local_str);
1807                                         ilgen.Emit (OpCodes.Ldloc, loc_start);
1808                                         ilgen.Emit (OpCodes.Callvirt, typeof (string).GetMethod ("get_Chars"));
1809                                         if (ignore)
1810                                                 ilgen.Emit (OpCodes.Callvirt, typeof (TextInfo).GetMethod ("ToLower", new Type [] { typeof (char) }));
1811                                         ilgen.Emit (OpCodes.Bne_Un, frame.label_fail);
1812                                         // strpos++;
1813                                         ilgen.Emit (OpCodes.Ldarg_1);
1814                                         ilgen.Emit (OpCodes.Ldc_I4_1);
1815                                         ilgen.Emit (OpCodes.Add);
1816                                         ilgen.Emit (OpCodes.Starg, 1);
1817                                         // start++
1818                                         ilgen.Emit (OpCodes.Ldloc, loc_start);
1819                                         ilgen.Emit (OpCodes.Ldc_I4_1);
1820                                         ilgen.Emit (OpCodes.Add);
1821                                         ilgen.Emit (OpCodes.Stloc, loc_start);
1822                                         // Loop footer
1823                                         ilgen.MarkLabel (l_loop_footer);
1824                                         ilgen.Emit (OpCodes.Ldloc, loc_start);
1825                                         ilgen.Emit (OpCodes.Ldloc, loc_end);
1826                                         ilgen.Emit (OpCodes.Blt, l_loop_body);
1827
1828                                         if (reverse) {
1829                                                 //ptr -= length;
1830                                                 ilgen.Emit (OpCodes.Ldarg_1);
1831                                                 ilgen.Emit (OpCodes.Ldloc, loc_length);
1832                                                 ilgen.Emit (OpCodes.Sub);
1833                                                 ilgen.Emit (OpCodes.Starg, 1);
1834                                         }
1835
1836                                         pc += 3;
1837                                         break;
1838                                 }
1839                                 case RxOp.Repeat:
1840                                 case RxOp.RepeatLazy:
1841                                 case RxOp.IfDefined:
1842                                         // FIXME:
1843                                         if (RxInterpreter.trace_rx || trace_compile)
1844                                                 Console.WriteLine ("Opcode " + op + " not supported.");
1845                                         return null;
1846                                 default:
1847                                         throw new NotImplementedException ("Opcode '" + op + "' not supported by the regex->IL compiler.");
1848                             }
1849
1850                                 if (one_op)
1851                                         break;
1852                         }
1853
1854                         End:
1855
1856                         out_pc = pc;
1857
1858                         return m;
1859                 }
1860         }
1861
1862 }
1863