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           DEBUG_Printf(DBG_CHN_MESG, "%s\n", exp->un.symbol.name);
 338           RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 339       }
 340       break;
 341     case EXPR_TYPE_PSTRUCT:
 342       exp1 =  DEBUG_EvalExpr(exp->un.structure.exp1);
 343       if( exp1.type == NULL )
 344         {
 345            RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 346         }
 347       rtn.cookie = DV_TARGET;
 348       rtn.addr.off = DEBUG_TypeDerefPointer(&exp1, &rtn.type);
 349       if( rtn.type == NULL )
 350         {
 351           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 352         }
 353       if (!DEBUG_FindStructElement(&rtn, exp->un.structure.element_name,
 354                                    &exp->un.structure.result))
 355       {
 356           DEBUG_Printf(DBG_CHN_MESG, "%s\n", exp->un.structure.element_name);
 357           RaiseException(DEBUG_STATUS_NO_FIELD, 0, 0, NULL);
 358       }
 359
 360       break;
 361     case EXPR_TYPE_STRUCT:
 362       exp1 =  DEBUG_EvalExpr(exp->un.structure.exp1);
 363       if( exp1.type == NULL )
 364       {
 365           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 366       }
 367       rtn = exp1;
 368       if (!DEBUG_FindStructElement(&rtn, exp->un.structure.element_name,
 369                                    &exp->un.structure.result))
 370       {
 371           DEBUG_Printf(DBG_CHN_MESG, "%s\n", exp->un.structure.element_name);
 372           RaiseException(DEBUG_STATUS_NO_FIELD, 0, 0, NULL);
 373       }
 374       break;
 375     case EXPR_TYPE_CALL:
 376       /*
 377        * First, evaluate all of the arguments.  If any of them are not
 378        * evaluable, then bail.
 379        */
 380       for(i=0; i < exp->un.call.nargs; i++)
 381         {
 382           exp1  = DEBUG_EvalExpr(exp->un.call.arg[i]);
 383           if( exp1.type == NULL )
 384             {
 385               return rtn;
 386             }
 387           cexp[i] = DEBUG_GetExprValue(&exp1, NULL);
 388         }
 389
 390       /*
 391        * Now look up the address of the function itself.
 392        */
 393       if( !DEBUG_GetSymbolValue(exp->un.call.funcname, -1, &rtn, FALSE ) )
 394         {
 395           RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 396         }
 397
 398 #if 0
 399       /* FIXME: NEWDBG NIY */
 400       /* Anyway, I wonder how this could work depending on the calling order of
 401        * the function (cdecl vs pascal for example)
 402        */
 403       int               (*fptr)();
 404
 405       fptr = (int (*)()) rtn.addr.off;
 406       switch(exp->un.call.nargs)
 407         {
 408         case 0:
 409           exp->un.call.result = (*fptr)();
 410           break;
 411         case 1:
 412           exp->un.call.result = (*fptr)(cexp[0]);
 413           break;
 414         case 2:
 415           exp->un.call.result = (*fptr)(cexp[0], cexp[1]);
 416           break;
 417         case 3:
 418           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2]);
 419           break;
 420         case 4:
 421           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2], cexp[3]);
 422           break;
 423         case 5:
 424           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2], cexp[3], cexp[4]);
 425           break;
 426         }
 427 #else
 428       DEBUG_Printf(DBG_CHN_MESG, "Function call no longer implemented\n");
 429       /* would need to set up a call to this function, and then restore the current
 430        * context afterwards...
 431        */
 432       exp->un.call.result = 0;
 433 #endif
 434       rtn.type = DEBUG_TypeInt;
 435       rtn.cookie = DV_HOST;
 436       rtn.addr.off = (unsigned int) &exp->un.call.result;
 437
 438       break;
 439     case EXPR_TYPE_INTVAR:
 440       {
 441
 442          DBG_INTVAR*    div = DEBUG_GetIntVar(exp->un.intvar.name);
 443
 444          if (!div) RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 445          rtn.cookie = DV_HOST;
 446          rtn.type = div->type;
 447          rtn.addr.off = (unsigned int)div->pval;
 448          /* EPP FIXME rtn.addr.seg = ?? */
 449       }
 450       break;
 451     case EXPR_TYPE_BINOP:
 452       exp1 = DEBUG_EvalExpr(exp->un.binop.exp1);
 453       exp2 = DEBUG_EvalExpr(exp->un.binop.exp2);
 454       rtn.cookie = DV_HOST;
 455       if( exp1.type == NULL || exp2.type == NULL )
 456         {
 457           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 458         }
 459       if( exp1.type == DEBUG_TypeIntConst && exp2.type == DEBUG_TypeIntConst )
 460         {
 461           rtn.type = exp1.type;
 462         }
 463       else
 464         {
 465           rtn.type = DEBUG_TypeInt;
 466         }
 467       rtn.addr.seg = 0;
 468       rtn.addr.off = (unsigned int) &exp->un.binop.result;
 469       switch(exp->un.binop.binop_type)
 470         {
 471         case EXP_OP_ADD:
 472           type1 = DEBUG_GetPointerType(exp1.type);
 473           type2 = DEBUG_GetPointerType(exp2.type);
 474           scale1 = 1;
 475           scale2 = 1;
 476           if( type1 != NULL && type2 != NULL )
 477             {
 478               RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 479             }
 480           else if( type1 != NULL )
 481             {
 482               scale2 = DEBUG_GetObjectSize(type1);
 483               rtn.type = exp1.type;
 484             }
 485           else if( type2 != NULL )
 486             {
 487               scale1 = DEBUG_GetObjectSize(type2);
 488               rtn.type = exp2.type;
 489             }
 490           exp->un.binop.result = (VAL(exp1) * scale1  + scale2 * VAL(exp2));
 491           break;
 492         case EXP_OP_SUB:
 493           type1 = DEBUG_GetPointerType(exp1.type);
 494           type2 = DEBUG_GetPointerType(exp2.type);
 495           scale1 = 1;
 496           scale2 = 1;
 497           scale3 = 1;
 498           if( type1 != NULL && type2 != NULL )
 499             {
 500               if( type1 != type2 )
 501                 {
 502                   RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 503                 }
 504               scale3 = DEBUG_GetObjectSize(type1);
 505             }
 506           else if( type1 != NULL )
 507             {
 508               scale2 = DEBUG_GetObjectSize(type1);
 509               rtn.type = exp1.type;
 510             }
 511
 512           else if( type2 != NULL )
 513             {
 514               scale1 = DEBUG_GetObjectSize(type2);
 515               rtn.type = exp2.type;
 516             }
 517           exp->un.binop.result = (VAL(exp1) - VAL(exp2)) / scale3;
 518           break;
 519         case EXP_OP_SEG:
 520           rtn.cookie = DV_TARGET;
 521           rtn.type = NULL;
 522           rtn.addr.seg = VAL(exp1);
 523           rtn.addr.off = VAL(exp2);
 524           break;
 525         case EXP_OP_LOR:
 526           exp->un.binop.result = (VAL(exp1) || VAL(exp2));
 527           break;
 528         case EXP_OP_LAND:
 529           exp->un.binop.result = (VAL(exp1) && VAL(exp2));
 530           break;
 531         case EXP_OP_OR:
 532           exp->un.binop.result = (VAL(exp1) | VAL(exp2));
 533           break;
 534         case EXP_OP_AND:
 535           exp->un.binop.result = (VAL(exp1) & VAL(exp2));
 536           break;
 537         case EXP_OP_XOR:
 538           exp->un.binop.result = (VAL(exp1) ^ VAL(exp2));
 539           break;
 540         case EXP_OP_EQ:
 541           exp->un.binop.result = (VAL(exp1) == VAL(exp2));
 542           break;
 543         case EXP_OP_GT:
 544           exp->un.binop.result = (VAL(exp1) > VAL(exp2));
 545           break;
 546         case EXP_OP_LT:
 547           exp->un.binop.result = (VAL(exp1) < VAL(exp2));
 548           break;
 549         case EXP_OP_GE:
 550           exp->un.binop.result = (VAL(exp1) >= VAL(exp2));
 551           break;
 552         case EXP_OP_LE:
 553           exp->un.binop.result = (VAL(exp1) <= VAL(exp2));
 554           break;
 555         case EXP_OP_NE:
 556           exp->un.binop.result = (VAL(exp1) != VAL(exp2));
 557           break;
 558         case EXP_OP_SHL:
 559           exp->un.binop.result = ((unsigned) VAL(exp1) << VAL(exp2));
 560           break;
 561         case EXP_OP_SHR:
 562           exp->un.binop.result = ((unsigned) VAL(exp1) >> VAL(exp2));
 563           break;
 564         case EXP_OP_MUL:
 565           exp->un.binop.result = (VAL(exp1) * VAL(exp2));
 566           break;
 567         case EXP_OP_DIV:
 568           if( VAL(exp2) == 0 )
 569             {
 570                RaiseException(DEBUG_STATUS_DIV_BY_ZERO, 0, 0, NULL);
 571             }
 572           exp->un.binop.result = (VAL(exp1) / VAL(exp2));
 573           break;
 574         case EXP_OP_REM:
 575           if( VAL(exp2) == 0 )
 576             {
 577                RaiseException(DEBUG_STATUS_DIV_BY_ZERO, 0, 0, NULL);
 578             }
 579           exp->un.binop.result = (VAL(exp1) % VAL(exp2));
 580           break;
 581         case EXP_OP_ARR:
 582           DEBUG_ArrayIndex(&exp1, &rtn, VAL(exp2));
 583           break;
 584         default:
 585           RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 586           break;
 587         }
 588       break;
 589     case EXPR_TYPE_UNOP:
 590       exp1 = DEBUG_EvalExpr(exp->un.unop.exp1);
 591       rtn.cookie = DV_HOST;
 592       if( exp1.type == NULL )
 593         {
 594           RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 595         }
 596       rtn.addr.seg = 0;
 597       rtn.addr.off = (unsigned int) &exp->un.unop.result;
 598       if( exp1.type == DEBUG_TypeIntConst )
 599         {
 600           rtn.type = exp1.type;
 601         }
 602       else
 603         {
 604           rtn.type = DEBUG_TypeInt;
 605         }
 606       switch(exp->un.unop.unop_type)
 607         {
 608         case EXP_OP_NEG:
 609           exp->un.unop.result = -VAL(exp1);
 610           break;
 611         case EXP_OP_NOT:
 612           exp->un.unop.result = !VAL(exp1);
 613           break;
 614         case EXP_OP_LNOT:
 615           exp->un.unop.result = ~VAL(exp1);
 616           break;
 617         case EXP_OP_DEREF:
 618           /* FIXME: this is currently buggy.
 619            * there is no way to tell were the deref:ed value is...
 620            * for example:
 621            *    x is a pointer to struct s, x being on the stack
 622            *            => exp1 is target, result is target
 623            *    x is a pointer to struct s, x being optimized into a reg
 624            *            => exp1 is host, result is target
 625            *    x is a pointer to internal variable x
 626            *            => exp1 is host, result is host
 627            * so we force DV_TARGET, because dereferencing pointers to
 628            * internal variables is very unlikely. a correct fix would be
 629            * rather large.
 630            */
 631           rtn.cookie = DV_TARGET;
 632           rtn.addr.off = (unsigned int) DEBUG_TypeDerefPointer(&exp1, &rtn.type);
 633           if (!rtn.type)
 634             {
 635               RaiseException(DEBUG_STATUS_BAD_TYPE, 0, 0, NULL);
 636             }
 637           break;
 638         case EXP_OP_FORCE_DEREF:
 639           rtn.cookie = exp1.cookie;
 640           rtn.addr.seg = exp1.addr.seg;
 641           if (exp1.cookie == DV_TARGET)
 642              DEBUG_READ_MEM((void*)exp1.addr.off, &rtn.addr.off, sizeof(rtn.addr.off));
 643           else
 644              memcpy(&rtn.addr.off, (void*)exp1.addr.off, sizeof(rtn.addr.off));
 645           break;
 646         case EXP_OP_ADDR:
 647           /* FIXME: even for a 16 bit entity ? */
 648           rtn.type = DEBUG_FindOrMakePointerType(exp1.type);
 649           exp->un.unop.result = exp1.addr.off;
 650           break;
 651         default:
 652            RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 653         }
 654       break;
 655     default:
 656       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression (%d).\n", exp->type);
 657       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 658       break;
 659     }
 660
 661   assert(rtn.cookie == DV_TARGET || rtn.cookie == DV_HOST);
 662
 663   return rtn;
 664 }
 665
 666
 667 int
 668 DEBUG_DisplayExpr(const struct expr * exp)
 669 {
 670   int           i;
 671
 672   switch(exp->type)
 673     {
 674     case EXPR_TYPE_CAST:
 675       DEBUG_Printf(DBG_CHN_MESG, "((");
 676       DEBUG_PrintTypeCast(exp->un.cast.cast);
 677       DEBUG_Printf(DBG_CHN_MESG, ")");
 678       DEBUG_DisplayExpr(exp->un.cast.expr);
 679       DEBUG_Printf(DBG_CHN_MESG, ")");
 680       break;
 681     case EXPR_TYPE_INTVAR:
 682       DEBUG_Printf(DBG_CHN_MESG, "$%s", exp->un.intvar.name);
 683       break;
 684     case EXPR_TYPE_US_CONST:
 685       DEBUG_Printf(DBG_CHN_MESG, "%ud", exp->un.u_const.value);
 686       break;
 687     case EXPR_TYPE_CONST:
 688       DEBUG_Printf(DBG_CHN_MESG, "%d", exp->un.u_const.value);
 689       break;
 690     case EXPR_TYPE_STRING:
 691       DEBUG_Printf(DBG_CHN_MESG, "\"%s\"", exp->un.string.str);
 692       break;
 693     case EXPR_TYPE_SYMBOL:
 694       DEBUG_Printf(DBG_CHN_MESG, "%s" , exp->un.symbol.name);
 695       break;
 696     case EXPR_TYPE_PSTRUCT:
 697       DEBUG_DisplayExpr(exp->un.structure.exp1);
 698       DEBUG_Printf(DBG_CHN_MESG, "->%s", exp->un.structure.element_name);
 699       break;
 700     case EXPR_TYPE_STRUCT:
 701       DEBUG_DisplayExpr(exp->un.structure.exp1);
 702       DEBUG_Printf(DBG_CHN_MESG, ".%s", exp->un.structure.element_name);
 703       break;
 704     case EXPR_TYPE_CALL:
 705       DEBUG_Printf(DBG_CHN_MESG, "%s(",exp->un.call.funcname);
 706       for(i=0; i < exp->un.call.nargs; i++)
 707         {
 708           DEBUG_DisplayExpr(exp->un.call.arg[i]);
 709           if( i != exp->un.call.nargs - 1 )
 710             {
 711               DEBUG_Printf(DBG_CHN_MESG, ", ");
 712             }
 713         }
 714       DEBUG_Printf(DBG_CHN_MESG, ")");
 715       break;
 716     case EXPR_TYPE_BINOP:
 717       DEBUG_Printf(DBG_CHN_MESG, "( ");
 718       DEBUG_DisplayExpr(exp->un.binop.exp1);
 719       switch(exp->un.binop.binop_type)
 720         {
 721         case EXP_OP_ADD:
 722           DEBUG_Printf(DBG_CHN_MESG, " + ");
 723           break;
 724         case EXP_OP_SUB:
 725           DEBUG_Printf(DBG_CHN_MESG, " - ");
 726           break;
 727         case EXP_OP_SEG:
 728           DEBUG_Printf(DBG_CHN_MESG, ":");
 729           break;
 730         case EXP_OP_LOR:
 731           DEBUG_Printf(DBG_CHN_MESG, " || ");
 732           break;
 733         case EXP_OP_LAND:
 734           DEBUG_Printf(DBG_CHN_MESG, " && ");
 735           break;
 736         case EXP_OP_OR:
 737           DEBUG_Printf(DBG_CHN_MESG, " | ");
 738           break;
 739         case EXP_OP_AND:
 740           DEBUG_Printf(DBG_CHN_MESG, " & ");
 741           break;
 742         case EXP_OP_XOR:
 743           DEBUG_Printf(DBG_CHN_MESG, " ^ ");
 744           break;
 745         case EXP_OP_EQ:
 746           DEBUG_Printf(DBG_CHN_MESG, " == ");
 747           break;
 748         case EXP_OP_GT:
 749           DEBUG_Printf(DBG_CHN_MESG, " > ");
 750           break;
 751         case EXP_OP_LT:
 752           DEBUG_Printf(DBG_CHN_MESG, " < ");
 753           break;
 754         case EXP_OP_GE:
 755           DEBUG_Printf(DBG_CHN_MESG, " >= ");
 756           break;
 757         case EXP_OP_LE:
 758           DEBUG_Printf(DBG_CHN_MESG, " <= ");
 759           break;
 760         case EXP_OP_NE:
 761           DEBUG_Printf(DBG_CHN_MESG, " != ");
 762           break;
 763         case EXP_OP_SHL:
 764           DEBUG_Printf(DBG_CHN_MESG, " << ");
 765           break;
 766         case EXP_OP_SHR:
 767           DEBUG_Printf(DBG_CHN_MESG, " >> ");
 768           break;
 769         case EXP_OP_MUL:
 770           DEBUG_Printf(DBG_CHN_MESG, " * ");
 771           break;
 772         case EXP_OP_DIV:
 773           DEBUG_Printf(DBG_CHN_MESG, " / ");
 774           break;
 775         case EXP_OP_REM:
 776           DEBUG_Printf(DBG_CHN_MESG, " %% ");
 777           break;
 778         case EXP_OP_ARR:
 779           DEBUG_Printf(DBG_CHN_MESG, "[");
 780           break;
 781         default:
 782           break;
 783         }
 784       DEBUG_DisplayExpr(exp->un.binop.exp2);
 785       if( exp->un.binop.binop_type == EXP_OP_ARR )
 786         {
 787           DEBUG_Printf(DBG_CHN_MESG, "]");
 788         }
 789       DEBUG_Printf(DBG_CHN_MESG, " )");
 790       break;
 791     case EXPR_TYPE_UNOP:
 792       switch(exp->un.unop.unop_type)
 793         {
 794         case EXP_OP_NEG:
 795           DEBUG_Printf(DBG_CHN_MESG, "-");
 796           break;
 797         case EXP_OP_NOT:
 798           DEBUG_Printf(DBG_CHN_MESG, "!");
 799           break;
 800         case EXP_OP_LNOT:
 801           DEBUG_Printf(DBG_CHN_MESG, "~");
 802           break;
 803         case EXP_OP_DEREF:
 804           DEBUG_Printf(DBG_CHN_MESG, "*");
 805           break;
 806         case EXP_OP_ADDR:
 807           DEBUG_Printf(DBG_CHN_MESG, "&");
 808           break;
 809         }
 810       DEBUG_DisplayExpr(exp->un.unop.exp1);
 811       break;
 812     default:
 813       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression.\n");
 814       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 815       break;
 816     }
 817
 818   return TRUE;
 819 }
 820
 821 struct expr *
 822 DEBUG_CloneExpr(const struct expr * exp)
 823 {
 824   int           i;
 825   struct expr * rtn;
 826
 827   rtn = (struct expr *) DBG_alloc(sizeof(struct expr));
 828
 829   /*
 830    * First copy the contents of the expression itself.
 831    */
 832   *rtn = *exp;
 833
 834
 835   switch(exp->type)
 836     {
 837     case EXPR_TYPE_CAST:
 838       rtn->un.cast.expr = DEBUG_CloneExpr(exp->un.cast.expr);
 839       break;
 840     case EXPR_TYPE_INTVAR:
 841       rtn->un.intvar.name = DBG_strdup(exp->un.intvar.name);
 842       break;
 843     case EXPR_TYPE_US_CONST:
 844     case EXPR_TYPE_CONST:
 845       break;
 846     case EXPR_TYPE_STRING:
 847       rtn->un.string.str = DBG_strdup(exp->un.string.str);
 848       break;
 849     case EXPR_TYPE_SYMBOL:
 850       rtn->un.symbol.name = DBG_strdup(exp->un.symbol.name);
 851       break;
 852     case EXPR_TYPE_PSTRUCT:
 853     case EXPR_TYPE_STRUCT:
 854       rtn->un.structure.exp1 = DEBUG_CloneExpr(exp->un.structure.exp1);
 855       rtn->un.structure.element_name = DBG_strdup(exp->un.structure.element_name);
 856       break;
 857     case EXPR_TYPE_CALL:
 858       for(i=0; i < exp->un.call.nargs; i++)
 859         {
 860           rtn->un.call.arg[i]  = DEBUG_CloneExpr(exp->un.call.arg[i]);
 861         }
 862       rtn->un.call.funcname = DBG_strdup(exp->un.call.funcname);
 863       break;
 864     case EXPR_TYPE_BINOP:
 865       rtn->un.binop.exp1 = DEBUG_CloneExpr(exp->un.binop.exp1);
 866       rtn->un.binop.exp2 = DEBUG_CloneExpr(exp->un.binop.exp2);
 867       break;
 868     case EXPR_TYPE_UNOP:
 869       rtn->un.unop.exp1 = DEBUG_CloneExpr(exp->un.unop.exp1);
 870       break;
 871     default:
 872       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression.\n");
 873       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 874       break;
 875     }
 876
 877   return rtn;
 878 }
 879
 880
 881 /*
 882  * Recursively go through an expression tree and free all memory associated
 883  * with it.
 884  */
 885 int
 886 DEBUG_FreeExpr(struct expr * exp)
 887 {
 888   int i;
 889
 890   switch(exp->type)
 891     {
 892     case EXPR_TYPE_CAST:
 893       DEBUG_FreeExpr(exp->un.cast.expr);
 894       break;
 895     case EXPR_TYPE_INTVAR:
 896       DBG_free((char *) exp->un.intvar.name);
 897       break;
 898     case EXPR_TYPE_US_CONST:
 899     case EXPR_TYPE_CONST:
 900       break;
 901     case EXPR_TYPE_STRING:
 902       DBG_free((char *) exp->un.string.str);
 903       break;
 904     case EXPR_TYPE_SYMBOL:
 905       DBG_free((char *) exp->un.symbol.name);
 906       break;
 907     case EXPR_TYPE_PSTRUCT:
 908     case EXPR_TYPE_STRUCT:
 909       DEBUG_FreeExpr(exp->un.structure.exp1);
 910       DBG_free((char *) exp->un.structure.element_name);
 911       break;
 912     case EXPR_TYPE_CALL:
 913       for(i=0; i < exp->un.call.nargs; i++)
 914         {
 915           DEBUG_FreeExpr(exp->un.call.arg[i]);
 916         }
 917       DBG_free((char *) exp->un.call.funcname);
 918       break;
 919     case EXPR_TYPE_BINOP:
 920       DEBUG_FreeExpr(exp->un.binop.exp1);
 921       DEBUG_FreeExpr(exp->un.binop.exp2);
 922       break;
 923     case EXPR_TYPE_UNOP:
 924       DEBUG_FreeExpr(exp->un.unop.exp1);
 925       break;
 926     default:
 927       DEBUG_Printf(DBG_CHN_MESG,"Unexpected expression.\n");
 928       RaiseException(DEBUG_STATUS_INTERNAL_ERROR, 0, 0, NULL);
 929       break;
 930     }
 931
 932   DBG_free(exp);
 933   return TRUE;
 934 }