debugger/expr.c

   1 /*
   2  * File expr.c - expression handling for Wine internal debugger.
   3  *
   4  * Copyright (C) 1997, Eric Youngdale.
   5  *
   6  */
   7
   8 #include "config.h"
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include "winbase.h"
  12 #include "wine/winbase16.h"
  13 #include "debugger.h"
  14 #include "expr.h"
  15
  16 #include <stdarg.h>
  17
  18 struct expr
  19 {
  20   unsigned int  perm;
  21   unsigned int  type:31;
  22   union
  23   {
  24     struct
  25     {
  26       int value;
  27     } constant;
  28
  29     struct
  30     {
  31       const char * str;
  32     } string;
  33
  34     struct
  35     {
  36       unsigned int value;
  37     } u_const;
  38
  39     struct
  40     {
  41       const char * name;
  42     } symbol;
  43
  44     struct
  45     {
  46       const char * name;
  47     } intvar;
  48
  49     struct
  50     {
  51       int unop_type;
  52       struct expr * exp1;
  53       int             result;
  54     } unop;
  55
  56     struct
  57     {
  58       int binop_type;
  59       int result;
  60       struct expr * exp1;
  61       struct expr * exp2;
  62     } binop;
  63
  64     struct
  65     {
  66       struct datatype * cast;
  67       struct expr     * expr;
  68     } cast;
  69
  70     struct
  71     {
  72       struct expr * exp1;
  73       const char * element_name;
  74       int result;
  75     } structure;
  76
  77     struct
  78     {
  79       struct expr * base;
  80       struct expr * index;
  81     } array;
  82
  83     struct
  84     {
  85       const char  * funcname;
  86       int           nargs;
  87       int           result;
  88       struct expr * arg[5];
  89     } call;
  90
  91   } un;
  92 };
  93
  94 #define EXPR_TYPE_CONST         0
  95 #define EXPR_TYPE_US_CONST      1
  96 #define EXPR_TYPE_SYMBOL        2
  97 #define EXPR_TYPE_INTVAR        3
  98 #define EXPR_TYPE_BINOP         4
  99 #define EXPR_TYPE_UNOP          5
 100 #define EXPR_TYPE_STRUCT        6
 101 #define EXPR_TYPE_PSTRUCT       7
 102 #define EXPR_TYPE_ARRAY         8
 103 #define EXPR_TYPE_CALL          9
 104 #define EXPR_TYPE_STRING        10
 105 #define EXPR_TYPE_CAST          11
 106
 107 static char expr_list[4096];
 108 static unsigned int next_expr_free = 0;
 109
 110 /*
 111  * This is how we turn an expression address into the actual value.
 112  * This works well in the 32 bit domain - not sure at all about the
 113  * 16 bit world.
 114  */
 115 #define VAL(_exp)       DEBUG_GetExprValue(&_exp, NULL)
 116
 117 static
 118 struct expr *
 119 DEBUG_GetFreeExpr(void)
 120 {
 121   struct expr * rtn;
 122
 123   rtn =  (struct expr *) &expr_list[next_expr_free];
 124
 125   next_expr_free += sizeof(struct expr);
 126   assert(next_expr_free < sizeof(expr_list));
 127
 128   return rtn;
 129 }
 130
 131 void
 132 DEBUG_FreeExprMem(void)
 133 {
 134   next_expr_free = 0;
 135 }
 136
 137 struct expr *
 138 DEBUG_TypeCastExpr(struct datatype * dt, struct expr * exp)
 139 {
 140   struct expr * ex;
 141
 142   ex = DEBUG_GetFreeExpr();
 143
 144   ex->type        = EXPR_TYPE_CAST;
 145   ex->un.cast.cast = dt;
 146   ex->un.cast.expr = exp;
 147   return ex;
 148 }
 149
 150 struct expr *
 151 DEBUG_IntVarExpr(const char* name)
 152 {
 153   struct expr * ex;
 154
 155   ex = DEBUG_GetFreeExpr();
 156
 157   ex->type        = EXPR_TYPE_INTVAR;
 158   ex->un.intvar.name = name;
 159   return ex;
 160 }
 161
 162 struct expr *
 163 DEBUG_SymbolExpr(const char * name)
 164 {
 165   struct expr * ex;
 166
 167   ex = DEBUG_GetFreeExpr();
 168
 169   ex->type        = EXPR_TYPE_SYMBOL;
 170   ex->un.symbol.name = name;
 171   return ex;
 172 }
 173
 174 struct expr *
 175 DEBUG_ConstExpr(int value)
 176 {
 177   struct expr * ex;
 178
 179   ex = DEBUG_GetFreeExpr();
 180
 181   ex->type        = EXPR_TYPE_CONST;
 182   ex->un.constant.value = value;
 183   return ex;
 184 }
 185
 186 struct expr *
 187 DEBUG_StringExpr(const char * str)
 188 {
 189   struct expr * ex;
 190   char * pnt;
 191   ex = DEBUG_GetFreeExpr();
 192
 193   ex->type        = EXPR_TYPE_STRING;
 194   ex->un.string.str = str+1;
 195   pnt = strrchr(ex->un.string.str, '"');
 196   if( pnt != NULL )
 197     {
 198       *pnt =  '\0';
 199     }
 200   return ex;
 201 }
 202
 203 struct expr *
 204 DEBUG_USConstExpr(unsigned int value)
 205 {
 206   struct expr * ex;
 207
 208   ex = DEBUG_GetFreeExpr();
 209
 210   ex->type           = EXPR_TYPE_CONST;
 211   ex->un.u_const.value = value;
 212   return ex;
 213 }
 214
 215 struct expr *
 216 DEBUG_BinopExpr(int operator_type, struct expr * exp1, struct expr * exp2)
 217 {
 218   struct expr * ex;
 219
 220   ex = DEBUG_GetFreeExpr();
 221
 222   ex->type           = EXPR_TYPE_BINOP;
 223   ex->un.binop.binop_type = operator_type;
 224   ex->un.binop.exp1     = exp1;
 225   ex->un.binop.exp2     = exp2;
 226   return ex;
 227 }
 228
 229 struct expr *
 230 DEBUG_UnopExpr(int operator_type, struct expr * exp1)
 231 {
 232   struct expr * ex;
 233
 234   ex = DEBUG_GetFreeExpr();
 235
 236   ex->type           = EXPR_TYPE_UNOP;
 237   ex->un.unop.unop_type = operator_type;
 238   ex->un.unop.exp1      = exp1;
 239   return ex;
 240 }
 241
 242 struct expr *
 243 DEBUG_StructExpr(struct expr * exp, const char * element)
 244 {
 245   struct expr * ex;
 246
 247   ex = DEBUG_GetFreeExpr();
 248
 249   ex->type           = EXPR_TYPE_STRUCT;
 250   ex->un.structure.exp1 = exp;
 251   ex->un.structure.element_name = element;
 252   return ex;
 253 }
 254
 255 struct expr *
 256 DEBUG_StructPExpr(struct expr * exp, const char * element)
 257 {
 258   struct expr * ex;
 259
 260   ex = DEBUG_GetFreeExpr();
 261
 262   ex->type           = EXPR_TYPE_PSTRUCT;
 263   ex->un.structure.exp1 = exp;
 264   ex->un.structure.element_name = element;
 265   return ex;
 266 }
 267
 268 struct expr *
 269 DEBUG_CallExpr(const char * funcname, int nargs, ...)
 270 {
 271   struct expr * ex;
 272   va_list ap;
 273   int i;
 274
 275   ex = DEBUG_GetFreeExpr();
 276
 277   ex->type           = EXPR_TYPE_CALL;
 278   ex->un.call.funcname = funcname;
 279   ex->un.call.nargs = nargs;
 280
 281   va_start(ap, nargs);
 282   for(i=0; i < nargs; i++)
 283     {
 284       ex->un.call.arg[i] = va_arg(ap, struct expr *);
 285     }
 286   va_end(ap);
 287   return ex;
 288 }
 289
 290 DBG_VALUE DEBUG_EvalExpr(struct expr * exp)
 291 {
 292   DBG_VALUE     rtn;
 293   int           i;
 294   DBG_VALUE     exp1;
 295   DBG_VALUE     exp2;
 296   unsigned int  cexp[5];
 297   int               scale1;
 298   int               scale2;
 299   int               scale3;
 300   struct datatype * type1;
 301   struct datatype * type2;
 302
 303   rtn.type = NULL;
 304   rtn.cookie = DV_INVALID;
 305   rtn.addr.off = 0;
 306   rtn.addr.seg = 0;
 307
 308   switch(exp->type)
 309     {
 310     case EXPR_TYPE_CAST:
 311       rtn = DEBUG_EvalExpr(exp->un.cast.expr);
 312       rtn.type = exp->un.cast.cast;
 313       if (DEBUG_GetType(rtn.type) == DT_POINTER)
 314          rtn.cookie = DV_TARGET;
 315       break;
 316     case EXPR_TYPE_STRING:
 317       rtn.type = DEBUG_TypeString;
 318       rtn.cookie = DV_HOST;
 319       rtn.addr.off = (unsigned int) &exp->un.string.str;
 320       rtn.addr.seg = 0;
 321       break;
 322     case EXPR_TYPE_CONST:
 323       rtn.type = DEBUG_TypeIntConst;
 324       rtn.cookie = DV_HOST;
 325       rtn.addr.off = (unsigned int) &exp->un.constant.value;
 326       rtn.addr.seg = 0;
 327       break;
 328     case EXPR_TYPE_US_CONST:
 329       rtn.type = DEBUG_TypeUSInt;
 330       rtn.cookie = DV_HOST;
 331       rtn.addr.off = (unsigned int) &exp->un.u_const.value;
 332       rtn.addr.seg = 0;
 333       break;
 334     case EXPR_TYPE_SYMBOL:
 335       if( !DEBUG_GetSymbolValue(exp->un.symbol.name, -1, &rtn, FALSE) )
 336         {
 337            RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 338         }
 339       break;
 340     case EXPR_TYPE_PSTRUCT:
 341       exp1 =  DEBUG_EvalExpr(exp->un.structure.exp1);
 342       if( exp1.type == NULL )
 343         {
 344            RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 345         }
 346       rtn.cookie = DV_TARGET;
 347       rtn.addr.off = DEBUG_TypeDerefPointer(&exp1, &type1);
 348       if( type1 == NULL )
 349         {
 350           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 351         }
 352       rtn.type = type1;
 353       DEBUG_FindStructElement(&rtn, exp->un.structure.element_name,
 354                               &exp->un.structure.result);
 355       break;
 356     case EXPR_TYPE_STRUCT:
 357       exp1 =  DEBUG_EvalExpr(exp->un.structure.exp1);
 358       if( exp1.type == NULL )
 359         {
 360           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 361         }
 362       rtn = exp1;
 363       DEBUG_FindStructElement(&rtn, exp->un.structure.element_name,
 364                               &exp->un.structure.result);
 365       break;
 366     case EXPR_TYPE_CALL:
 367       /*
 368        * First, evaluate all of the arguments.  If any of them are not
 369        * evaluable, then bail.
 370        */
 371       for(i=0; i < exp->un.call.nargs; i++)
 372         {
 373           exp1  = DEBUG_EvalExpr(exp->un.call.arg[i]);
 374           if( exp1.type == NULL )
 375             {
 376               return rtn;
 377             }
 378           cexp[i] = DEBUG_GetExprValue(&exp1, NULL);
 379         }
 380
 381       /*
 382        * Now look up the address of the function itself.
 383        */
 384       if( !DEBUG_GetSymbolValue(exp->un.call.funcname, -1, &rtn, FALSE ) )
 385         {
 386           RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 387         }
 388
 389 #if 0
 390       /* FIXME: NEWDBG NIY */
 391       /* Anyway, I wonder how this could work depending on the calling order of
 392        * the function (cdecl vs pascal for example)
 393        */
 394       int               (*fptr)();
 395
 396       fptr = (int (*)()) rtn.addr.off;
 397       switch(exp->un.call.nargs)
 398         {
 399         case 0:
 400           exp->un.call.result = (*fptr)();
 401           break;
 402         case 1:
 403           exp->un.call.result = (*fptr)(cexp[0]);
 404           break;
 405         case 2:
 406           exp->un.call.result = (*fptr)(cexp[0], cexp[1]);
 407           break;
 408         case 3:
 409           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2]);
 410           break;
 411         case 4:
 412           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2], cexp[3]);
 413           break;
 414         case 5:
 415           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2], cexp[3], cexp[4]);
 416           break;
 417         }
 418 #else
 419       DEBUG_Printf(DBG_CHN_MESG, "Function call no longer implemented\n");
 420       /* would need to set up a call to this function, and then restore the current
 421        * context afterwards...
 422        */
 423       exp->un.call.result = 0;
 424 #endif
 425       rtn.type = DEBUG_TypeInt;
 426       rtn.cookie = DV_HOST;
 427       rtn.addr.off = (unsigned int) &exp->un.call.result;
 428
 429       break;
 430     case EXPR_TYPE_INTVAR:
 431       {
 432
 433          DBG_INTVAR*    div = DEBUG_GetIntVar(exp->un.intvar.name);
 434
 435          if (!div) RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 436          rtn.cookie = DV_HOST;
 437          rtn.type = div->type;
 438          rtn.addr.off = (unsigned int)div->pval;
 439          /* EPP FIXME rtn.addr.seg = ?? */
 440       }
 441       break;
 442     case EXPR_TYPE_BINOP:
 443       exp1 = DEBUG_EvalExpr(exp->un.binop.exp1);
 444       exp2 = DEBUG_EvalExpr(exp->un.binop.exp2);
 445       rtn.cookie = DV_HOST;
 446       if( exp1.type == NULL || exp2.type == NULL )
 447         {
 448           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 449         }
 450       if( exp1.type == DEBUG_TypeIntConst && exp2.type == DEBUG_TypeIntConst )
 451         {
 452           rtn.type = exp1.type;
 453         }
 454       else
 455         {
 456           rtn.type = DEBUG_TypeInt;
 457         }
 458       rtn.addr.seg = 0;
 459       rtn.addr.off = (unsigned int) &exp->un.binop.result;
 460       switch(exp->un.binop.binop_type)
 461         {
 462         case EXP_OP_ADD:
 463           type1 = DEBUG_GetPointerType(exp1.type);
 464           type2 = DEBUG_GetPointerType(exp2.type);
 465           scale1 = 1;
 466           scale2 = 1;
 467           if( type1 != NULL && type2 != NULL )
 468             {
 469               RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 470             }
 471           else if( type1 != NULL )
 472             {
 473               scale2 = DEBUG_GetObjectSize(type1);
 474               rtn.type = exp1.type;
 475             }
 476           else if( type2 != NULL )
 477             {
 478               scale1 = DEBUG_GetObjectSize(type2);
 479               rtn.type = exp2.type;
 480             }
 481           exp->un.binop.result = (VAL(exp1) * scale1  + scale2 * VAL(exp2));
 482           break;
 483         case EXP_OP_SUB:
 484           type1 = DEBUG_GetPointerType(exp1.type);
 485           type2 = DEBUG_GetPointerType(exp2.type);
 486           scale1 = 1;
 487           scale2 = 1;
 488           scale3 = 1;
 489           if( type1 != NULL && type2 != NULL )
 490             {
 491               if( type1 != type2 )
 492                 {
 493                   RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 494                 }
 495               scale3 = DEBUG_GetObjectSize(type1);
 496             }
 497           else if( type1 != NULL )
 498             {
 499               scale2 = DEBUG_GetObjectSize(type1);
 500               rtn.type = exp1.type;
 501             }
 502
 503           else if( type2 != NULL )
 504             {
 505               scale1 = DEBUG_GetObjectSize(type2);
 506               rtn.type = exp2.type;
 507             }
 508           exp->un.binop.result = (VAL(exp1) - VAL(exp2)) / scale3;
 509           break;
 510         case EXP_OP_SEG:
 511           rtn.cookie = DV_TARGET;
 512           rtn.type = NULL;
 513           rtn.addr.seg = VAL(exp1);
 514           rtn.addr.off = VAL(exp2);
 515           break;
 516         case EXP_OP_LOR:
 517           exp->un.binop.result = (VAL(exp1) || VAL(exp2));
 518           break;
 519         case EXP_OP_LAND:
 520           exp->un.binop.result = (VAL(exp1) && VAL(exp2));
 521           break;
 522         case EXP_OP_OR:
 523           exp->un.binop.result = (VAL(exp1) | VAL(exp2));
 524           break;
 525         case EXP_OP_AND:
 526           exp->un.binop.result = (VAL(exp1) & VAL(exp2));
 527           break;
 528         case EXP_OP_XOR:
 529           exp->un.binop.result = (VAL(exp1) ^ VAL(exp2));
 530           break;
 531         case EXP_OP_EQ:
 532           exp->un.binop.result = (VAL(exp1) == VAL(exp2));
 533           break;
 534         case EXP_OP_GT:
 535           exp->un.binop.result = (VAL(exp1) > VAL(exp2));
 536           break;
 537         case EXP_OP_LT:
 538           exp->un.binop.result = (VAL(exp1) < VAL(exp2));
 539           break;
 540         case EXP_OP_GE:
 541           exp->un.binop.result = (VAL(exp1) >= VAL(exp2));
 542           break;
 543         case EXP_OP_LE:
 544           exp->un.binop.result = (VAL(exp1) <= VAL(exp2));
 545           break;
 546         case EXP_OP_NE:
 547           exp->un.binop.result = (VAL(exp1) != VAL(exp2));
 548           break;
 549         case EXP_OP_SHL:
 550           exp->un.binop.result = ((unsigned) VAL(exp1) << VAL(exp2));
 551           break;
 552         case EXP_OP_SHR:
 553           exp->un.binop.result = ((unsigned) VAL(exp1) >> VAL(exp2));
 554           break;
 555         case EXP_OP_MUL:
 556           exp->un.binop.result = (VAL(exp1) * VAL(exp2));
 557           break;
 558         case EXP_OP_DIV:
 559           if( VAL(exp2) == 0 )
 560             {
 561                RaiseException(DEBUG_STATUS_DIV_BY_ZERO, 0, 0, NULL);
 562             }
 563           exp->un.binop.result = (VAL(exp1) / VAL(exp2));
 564           break;
 565         case EXP_OP_REM:
 566           if( VAL(exp2) == 0 )
 567             {
 568                RaiseException(DEBUG_STATUS_DIV_BY_ZERO, 0, 0, NULL);
 569             }
 570           exp->un.binop.result = (VAL(exp1) % VAL(exp2));
 571           break;
 572         case EXP_OP_ARR:
 573           DEBUG_ArrayIndex(&exp1, &rtn, VAL(exp2));
 574           break;
 575         default:
 576           RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 577           break;
 578         }
 579       break;
 580     case EXPR_TYPE_UNOP:
 581       exp1 = DEBUG_EvalExpr(exp->un.unop.exp1);
 582       rtn.cookie = DV_HOST;
 583       if( exp1.type == NULL )
 584         {
 585           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 586         }
 587       rtn.addr.seg = 0;
 588       rtn.addr.off = (unsigned int) &exp->un.unop.result;
 589       if( exp1.type == DEBUG_TypeIntConst )
 590         {
 591           rtn.type = exp1.type;
 592         }
 593       else
 594         {
 595           rtn.type = DEBUG_TypeInt;
 596         }
 597       switch(exp->un.unop.unop_type)
 598         {
 599         case EXP_OP_NEG:
 600           exp->un.unop.result = -VAL(exp1);
 601           break;
 602         case EXP_OP_NOT:
 603           exp->un.unop.result = !VAL(exp1);
 604           break;
 605         case EXP_OP_LNOT:
 606           exp->un.unop.result = ~VAL(exp1);
 607           break;
 608         case EXP_OP_DEREF:
 609           /* FIXME: this is currently buggy.
 610            * there is no way to tell were the deref:ed value is...
 611            * for example:
 612            *    x is a pointer to struct s, x being on the stack
 613            *            => exp1 is target, result is target
 614            *    x is a pointer to struct s, x being optimized into a reg
 615            *            => exp1 is host, result is target
 616            *    x is a pointer to internal variable x
 617            *            => exp1 is host, result is host
 618            * so we force DV_TARGET, because dereferencing pointers to
 619            * internal variables is very unlikely. a correct fix would be
 620            * rather large.
 621            */
 622           rtn.cookie = DV_TARGET;
 623           rtn.addr.off = (unsigned int) DEBUG_TypeDerefPointer(&exp1, &rtn.type);
 624           if (!rtn.type)
 625             {
 626               RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 627             }
 628           break;
 629         case EXP_OP_FORCE_DEREF:
 630           rtn.cookie = exp1.cookie;
 631           rtn.addr.seg = exp1.addr.seg;
 632           if (exp1.cookie == DV_TARGET)
 633              DEBUG_READ_MEM((void*)exp1.addr.off, &rtn.addr.off, sizeof(rtn.addr.off));
 634           else
 635              memcpy(&rtn.addr.off, (void*)exp1.addr.off, sizeof(rtn.addr.off));
 636           break;
 637         case EXP_OP_ADDR:
 638           /* FIXME: even for a 16 bit entity ? */
 639           rtn.type = DEBUG_FindOrMakePointerType(exp1.type);
 640           exp->un.unop.result = exp1.addr.off;
 641           break;
 642         default:
 643            RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 644         }
 645       break;
 646     default:
 647       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression (%d).\n", exp->type);
 648       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 649       break;
 650     }
 651
 652   assert(rtn.cookie == DV_TARGET || rtn.cookie == DV_HOST);
 653
 654   return rtn;
 655 }
 656
 657
 658 int
 659 DEBUG_DisplayExpr(const struct expr * exp)
 660 {
 661   int           i;
 662
 663   switch(exp->type)
 664     {
 665     case EXPR_TYPE_CAST:
 666       DEBUG_Printf(DBG_CHN_MESG, "((");
 667       DEBUG_PrintTypeCast(exp->un.cast.cast);
 668       DEBUG_Printf(DBG_CHN_MESG, ")");
 669       DEBUG_DisplayExpr(exp->un.cast.expr);
 670       DEBUG_Printf(DBG_CHN_MESG, ")");
 671       break;
 672     case EXPR_TYPE_INTVAR:
 673       DEBUG_Printf(DBG_CHN_MESG, "$%s", exp->un.intvar.name);
 674       break;
 675     case EXPR_TYPE_US_CONST:
 676       DEBUG_Printf(DBG_CHN_MESG, "%ud", exp->un.u_const.value);
 677       break;
 678     case EXPR_TYPE_CONST:
 679       DEBUG_Printf(DBG_CHN_MESG, "%d", exp->un.u_const.value);
 680       break;
 681     case EXPR_TYPE_STRING:
 682       DEBUG_Printf(DBG_CHN_MESG, "\"%s\"", exp->un.string.str);
 683       break;
 684     case EXPR_TYPE_SYMBOL:
 685       DEBUG_Printf(DBG_CHN_MESG, "%s" , exp->un.symbol.name);
 686       break;
 687     case EXPR_TYPE_PSTRUCT:
 688       DEBUG_DisplayExpr(exp->un.structure.exp1);
 689       DEBUG_Printf(DBG_CHN_MESG, "->%s", exp->un.structure.element_name);
 690       break;
 691     case EXPR_TYPE_STRUCT:
 692       DEBUG_DisplayExpr(exp->un.structure.exp1);
 693       DEBUG_Printf(DBG_CHN_MESG, ".%s", exp->un.structure.element_name);
 694       break;
 695     case EXPR_TYPE_CALL:
 696       DEBUG_Printf(DBG_CHN_MESG, "%s(",exp->un.call.funcname);
 697       for(i=0; i < exp->un.call.nargs; i++)
 698         {
 699           DEBUG_DisplayExpr(exp->un.call.arg[i]);
 700           if( i != exp->un.call.nargs - 1 )
 701             {
 702               DEBUG_Printf(DBG_CHN_MESG, ", ");
 703             }
 704         }
 705       DEBUG_Printf(DBG_CHN_MESG, ")");
 706       break;
 707     case EXPR_TYPE_BINOP:
 708       DEBUG_Printf(DBG_CHN_MESG, "( ");
 709       DEBUG_DisplayExpr(exp->un.binop.exp1);
 710       switch(exp->un.binop.binop_type)
 711         {
 712         case EXP_OP_ADD:
 713           DEBUG_Printf(DBG_CHN_MESG, " + ");
 714           break;
 715         case EXP_OP_SUB:
 716           DEBUG_Printf(DBG_CHN_MESG, " - ");
 717           break;
 718         case EXP_OP_SEG:
 719           DEBUG_Printf(DBG_CHN_MESG, ":");
 720           break;
 721         case EXP_OP_LOR:
 722           DEBUG_Printf(DBG_CHN_MESG, " || ");
 723           break;
 724         case EXP_OP_LAND:
 725           DEBUG_Printf(DBG_CHN_MESG, " && ");
 726           break;
 727         case EXP_OP_OR:
 728           DEBUG_Printf(DBG_CHN_MESG, " | ");
 729           break;
 730         case EXP_OP_AND:
 731           DEBUG_Printf(DBG_CHN_MESG, " & ");
 732           break;
 733         case EXP_OP_XOR:
 734           DEBUG_Printf(DBG_CHN_MESG, " ^ ");
 735           break;
 736         case EXP_OP_EQ:
 737           DEBUG_Printf(DBG_CHN_MESG, " == ");
 738           break;
 739         case EXP_OP_GT:
 740           DEBUG_Printf(DBG_CHN_MESG, " > ");
 741           break;
 742         case EXP_OP_LT:
 743           DEBUG_Printf(DBG_CHN_MESG, " < ");
 744           break;
 745         case EXP_OP_GE:
 746           DEBUG_Printf(DBG_CHN_MESG, " >= ");
 747           break;
 748         case EXP_OP_LE:
 749           DEBUG_Printf(DBG_CHN_MESG, " <= ");
 750           break;
 751         case EXP_OP_NE:
 752           DEBUG_Printf(DBG_CHN_MESG, " != ");
 753           break;
 754         case EXP_OP_SHL:
 755           DEBUG_Printf(DBG_CHN_MESG, " << ");
 756           break;
 757         case EXP_OP_SHR:
 758           DEBUG_Printf(DBG_CHN_MESG, " >> ");
 759           break;
 760         case EXP_OP_MUL:
 761           DEBUG_Printf(DBG_CHN_MESG, " * ");
 762           break;
 763         case EXP_OP_DIV:
 764           DEBUG_Printf(DBG_CHN_MESG, " / ");
 765           break;
 766         case EXP_OP_REM:
 767           DEBUG_Printf(DBG_CHN_MESG, " %% ");
 768           break;
 769         case EXP_OP_ARR:
 770           DEBUG_Printf(DBG_CHN_MESG, "[");
 771           break;
 772         default:
 773           break;
 774         }
 775       DEBUG_DisplayExpr(exp->un.binop.exp2);
 776       if( exp->un.binop.binop_type == EXP_OP_ARR )
 777         {
 778           DEBUG_Printf(DBG_CHN_MESG, "]");
 779         }
 780       DEBUG_Printf(DBG_CHN_MESG, " )");
 781       break;
 782     case EXPR_TYPE_UNOP:
 783       switch(exp->un.unop.unop_type)
 784         {
 785         case EXP_OP_NEG:
 786           DEBUG_Printf(DBG_CHN_MESG, "-");
 787           break;
 788         case EXP_OP_NOT:
 789           DEBUG_Printf(DBG_CHN_MESG, "!");
 790           break;
 791         case EXP_OP_LNOT:
 792           DEBUG_Printf(DBG_CHN_MESG, "~");
 793           break;
 794         case EXP_OP_DEREF:
 795           DEBUG_Printf(DBG_CHN_MESG, "*");
 796           break;
 797         case EXP_OP_ADDR:
 798           DEBUG_Printf(DBG_CHN_MESG, "&");
 799           break;
 800         }
 801       DEBUG_DisplayExpr(exp->un.unop.exp1);
 802       break;
 803     default:
 804       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression.\n");
 805       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 806       break;
 807     }
 808
 809   return TRUE;
 810 }
 811
 812 struct expr *
 813 DEBUG_CloneExpr(const struct expr * exp)
 814 {
 815   int           i;
 816   struct expr * rtn;
 817
 818   rtn = (struct expr *) DBG_alloc(sizeof(struct expr));
 819
 820   /*
 821    * First copy the contents of the expression itself.
 822    */
 823   *rtn = *exp;
 824
 825
 826   switch(exp->type)
 827     {
 828     case EXPR_TYPE_CAST:
 829       rtn->un.cast.expr = DEBUG_CloneExpr(exp->un.cast.expr);
 830       break;
 831     case EXPR_TYPE_INTVAR:
 832       rtn->un.intvar.name = DBG_strdup(exp->un.intvar.name);
 833       break;
 834     case EXPR_TYPE_US_CONST:
 835     case EXPR_TYPE_CONST:
 836       break;
 837     case EXPR_TYPE_STRING:
 838       rtn->un.string.str = DBG_strdup(exp->un.string.str);
 839       break;
 840     case EXPR_TYPE_SYMBOL:
 841       rtn->un.symbol.name = DBG_strdup(exp->un.symbol.name);
 842       break;
 843     case EXPR_TYPE_PSTRUCT:
 844     case EXPR_TYPE_STRUCT:
 845       rtn->un.structure.exp1 = DEBUG_CloneExpr(exp->un.structure.exp1);
 846       rtn->un.structure.element_name = DBG_strdup(exp->un.structure.element_name);
 847       break;
 848     case EXPR_TYPE_CALL:
 849       for(i=0; i < exp->un.call.nargs; i++)
 850         {
 851           rtn->un.call.arg[i]  = DEBUG_CloneExpr(exp->un.call.arg[i]);
 852         }
 853       rtn->un.call.funcname = DBG_strdup(exp->un.call.funcname);
 854       break;
 855     case EXPR_TYPE_BINOP:
 856       rtn->un.binop.exp1 = DEBUG_CloneExpr(exp->un.binop.exp1);
 857       rtn->un.binop.exp2 = DEBUG_CloneExpr(exp->un.binop.exp2);
 858       break;
 859     case EXPR_TYPE_UNOP:
 860       rtn->un.unop.exp1 = DEBUG_CloneExpr(exp->un.unop.exp1);
 861       break;
 862     default:
 863       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression.\n");
 864       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 865       break;
 866     }
 867
 868   return rtn;
 869 }
 870
 871
 872 /*
 873  * Recursively go through an expression tree and free all memory associated
 874  * with it.
 875  */
 876 int
 877 DEBUG_FreeExpr(struct expr * exp)
 878 {
 879   int i;
 880
 881   switch(exp->type)
 882     {
 883     case EXPR_TYPE_CAST:
 884       DEBUG_FreeExpr(exp->un.cast.expr);
 885       break;
 886     case EXPR_TYPE_INTVAR:
 887       DBG_free((char *) exp->un.intvar.name);
 888       break;
 889     case EXPR_TYPE_US_CONST:
 890     case EXPR_TYPE_CONST:
 891       break;
 892     case EXPR_TYPE_STRING:
 893       DBG_free((char *) exp->un.string.str);
 894       break;
 895     case EXPR_TYPE_SYMBOL:
 896       DBG_free((char *) exp->un.symbol.name);
 897       break;
 898     case EXPR_TYPE_PSTRUCT:
 899     case EXPR_TYPE_STRUCT:
 900       DEBUG_FreeExpr(exp->un.structure.exp1);
 901       DBG_free((char *) exp->un.structure.element_name);
 902       break;
 903     case EXPR_TYPE_CALL:
 904       for(i=0; i < exp->un.call.nargs; i++)
 905         {
 906           DEBUG_FreeExpr(exp->un.call.arg[i]);
 907         }
 908       DBG_free((char *) exp->un.call.funcname);
 909       break;
 910     case EXPR_TYPE_BINOP:
 911       DEBUG_FreeExpr(exp->un.binop.exp1);
 912       DEBUG_FreeExpr(exp->un.binop.exp2);
 913       break;
 914     case EXPR_TYPE_UNOP:
 915       DEBUG_FreeExpr(exp->un.unop.exp1);
 916       break;
 917     default:
 918       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression.\n");
 919       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 920       break;
 921     }
 922
 923   DBG_free(exp);
 924   return TRUE;
 925 }