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 <stdio.h>
  11 #include <string.h>
  12 #include <assert.h>
  13 #include "winbase.h"
  14 #include "wine/winbase16.h"
  15 #include "task.h"
  16 #include "debugger.h"
  17 #include "expr.h"
  18
  19 #include <stdarg.h>
  20
  21 struct expr
  22 {
  23   unsigned int  perm;
  24   unsigned int  type:31;
  25   union
  26   {
  27     struct
  28     {
  29       int value;
  30     } constant;
  31
  32     struct
  33     {
  34       const char * str;
  35     } string;
  36
  37     struct
  38     {
  39       unsigned int value;
  40     } u_const;
  41
  42     struct
  43     {
  44       const char * name;
  45     } symbol;
  46
  47     struct
  48     {
  49       enum debug_regs reg;
  50       int             result;
  51     } rgister;
  52
  53     struct
  54     {
  55       int unop_type;
  56       struct expr * exp1;
  57       int             result;
  58     } unop;
  59
  60     struct
  61     {
  62       int binop_type;
  63       int result;
  64       struct expr * exp1;
  65       struct expr * exp2;
  66     } binop;
  67
  68     struct
  69     {
  70       struct datatype * cast;
  71       struct expr     * expr;
  72     } cast;
  73
  74     struct
  75     {
  76       struct expr * exp1;
  77       const char * element_name;
  78       int result;
  79     } structure;
  80
  81     struct
  82     {
  83       struct expr * base;
  84       struct expr * index;
  85     } array;
  86
  87     struct
  88     {
  89       const char  * funcname;
  90       int           nargs;
  91       int           result;
  92       struct expr * arg[5];
  93     } call;
  94
  95   } un;
  96 };
  97
  98 #define EXPR_TYPE_CONST         0
  99 #define EXPR_TYPE_US_CONST      1
 100 #define EXPR_TYPE_SYMBOL        2
 101 #define EXPR_TYPE_REGISTER      3
 102 #define EXPR_TYPE_BINOP         4
 103 #define EXPR_TYPE_UNOP          5
 104 #define EXPR_TYPE_STRUCT        6
 105 #define EXPR_TYPE_PSTRUCT       7
 106 #define EXPR_TYPE_ARRAY         8
 107 #define EXPR_TYPE_CALL          9
 108 #define EXPR_TYPE_STRING        10
 109 #define EXPR_TYPE_CAST          11
 110
 111 static char expr_list[4096];
 112 static int next_expr_free = 0;
 113
 114 /*
 115  * This is how we turn an expression address into the actual value.
 116  * This works well in the 32 bit domain - not sure at all about the
 117  * 16 bit world.
 118  */
 119 #define VAL(_exp)       DEBUG_GetExprValue(&_exp, NULL)
 120
 121 static
 122 struct expr *
 123 DEBUG_GetFreeExpr()
 124 {
 125   struct expr * rtn;
 126
 127   rtn =  (struct expr *) &expr_list[next_expr_free];
 128
 129   next_expr_free += sizeof(struct expr);
 130   assert(next_expr_free < sizeof(expr_list));
 131
 132   return rtn;
 133 }
 134
 135 void
 136 DEBUG_FreeExprMem()
 137 {
 138   next_expr_free = 0;
 139 }
 140
 141 struct expr *
 142 DEBUG_TypeCastExpr(struct datatype * dt, struct expr * exp)
 143 {
 144   struct expr * ex;
 145
 146   ex = DEBUG_GetFreeExpr();
 147
 148   ex->type        = EXPR_TYPE_CAST;
 149   ex->un.cast.cast = dt;
 150   ex->un.cast.expr = exp;
 151   return ex;
 152 }
 153
 154 struct expr *
 155 DEBUG_RegisterExpr(enum debug_regs regno)
 156 {
 157   struct expr * ex;
 158
 159   ex = DEBUG_GetFreeExpr();
 160
 161   ex->type        = EXPR_TYPE_REGISTER;
 162   ex->un.rgister.reg = regno;
 163   return ex;
 164 }
 165
 166 struct expr *
 167 DEBUG_SymbolExpr(const char * name)
 168 {
 169   struct expr * ex;
 170
 171   ex = DEBUG_GetFreeExpr();
 172
 173   ex->type        = EXPR_TYPE_SYMBOL;
 174   ex->un.symbol.name = name;
 175   return ex;
 176 }
 177
 178 struct expr *
 179 DEBUG_ConstExpr(int value)
 180 {
 181   struct expr * ex;
 182
 183   ex = DEBUG_GetFreeExpr();
 184
 185   ex->type        = EXPR_TYPE_CONST;
 186   ex->un.constant.value = value;
 187   return ex;
 188 }
 189
 190 struct expr *
 191 DEBUG_StringExpr(const char * str)
 192 {
 193   struct expr * ex;
 194   char * pnt;
 195   ex = DEBUG_GetFreeExpr();
 196
 197   ex->type        = EXPR_TYPE_STRING;
 198   ex->un.string.str = str+1;
 199   pnt = strrchr(ex->un.string.str, '"');
 200   if( pnt != NULL )
 201     {
 202       *pnt =  '\0';
 203     }
 204   return ex;
 205 }
 206
 207 struct expr *
 208 DEBUG_USConstExpr(unsigned int value)
 209 {
 210   struct expr * ex;
 211
 212   ex = DEBUG_GetFreeExpr();
 213
 214   ex->type           = EXPR_TYPE_CONST;
 215   ex->un.u_const.value = value;
 216   return ex;
 217 }
 218
 219 struct expr *
 220 DEBUG_BinopExpr(int operator_type, struct expr * exp1, struct expr * exp2)
 221 {
 222   struct expr * ex;
 223
 224   ex = DEBUG_GetFreeExpr();
 225
 226   ex->type           = EXPR_TYPE_BINOP;
 227   ex->un.binop.binop_type = operator_type;
 228   ex->un.binop.exp1     = exp1;
 229   ex->un.binop.exp2     = exp2;
 230   return ex;
 231 }
 232
 233 struct expr *
 234 DEBUG_UnopExpr(int operator_type, struct expr * exp1)
 235 {
 236   struct expr * ex;
 237
 238   ex = DEBUG_GetFreeExpr();
 239
 240   ex->type           = EXPR_TYPE_UNOP;
 241   ex->un.unop.unop_type = operator_type;
 242   ex->un.unop.exp1      = exp1;
 243   return ex;
 244 }
 245
 246 struct expr *
 247 DEBUG_StructExpr(struct expr * exp, const char * element)
 248 {
 249   struct expr * ex;
 250
 251   ex = DEBUG_GetFreeExpr();
 252
 253   ex->type           = EXPR_TYPE_STRUCT;
 254   ex->un.structure.exp1 = exp;
 255   ex->un.structure.element_name = element;
 256   return ex;
 257 }
 258
 259 struct expr *
 260 DEBUG_StructPExpr(struct expr * exp, const char * element)
 261 {
 262   struct expr * ex;
 263
 264   ex = DEBUG_GetFreeExpr();
 265
 266   ex->type           = EXPR_TYPE_PSTRUCT;
 267   ex->un.structure.exp1 = exp;
 268   ex->un.structure.element_name = element;
 269   return ex;
 270 }
 271
 272 struct expr *
 273 DEBUG_CallExpr(const char * funcname, int nargs, ...)
 274 {
 275   struct expr * ex;
 276   va_list ap;
 277   int i;
 278
 279   ex = DEBUG_GetFreeExpr();
 280
 281   ex->type           = EXPR_TYPE_CALL;
 282   ex->un.call.funcname = funcname;
 283   ex->un.call.nargs = nargs;
 284
 285   va_start(ap, nargs);
 286   for(i=0; i < nargs; i++)
 287     {
 288       ex->un.call.arg[i] = va_arg(ap, struct expr *);
 289     }
 290   va_end(ap);
 291   return ex;
 292 }
 293
 294 DBG_ADDR
 295 DEBUG_EvalExpr(struct expr * exp)
 296 {
 297   DBG_ADDR      rtn;
 298   int           i;
 299   DBG_ADDR      exp1;
 300   DBG_ADDR      exp2;
 301   unsigned int  cexp[5];
 302   int               scale1;
 303   int               scale2;
 304   int               scale3;
 305   struct datatype * type1;
 306   struct datatype * type2;
 307
 308   rtn.type = NULL;
 309   rtn.off = NULL;
 310   rtn.seg = NULL;
 311
 312   switch(exp->type)
 313     {
 314     case EXPR_TYPE_CAST:
 315       rtn = DEBUG_EvalExpr(exp->un.cast.expr);
 316       rtn.type = exp->un.cast.cast;
 317       break;
 318     case EXPR_TYPE_STRING:
 319       rtn.type = DEBUG_TypeString;
 320       rtn.off = (unsigned int) &exp->un.string.str;
 321       rtn.seg = 0;
 322       break;
 323     case EXPR_TYPE_CONST:
 324       rtn.type = DEBUG_TypeIntConst;
 325       rtn.off = (unsigned int) &exp->un.constant.value;
 326       rtn.seg = 0;
 327       break;
 328     case EXPR_TYPE_US_CONST:
 329       rtn.type = DEBUG_TypeUSInt;
 330       rtn.off = (unsigned int) &exp->un.u_const.value;
 331       rtn.seg = 0;
 332       break;
 333     case EXPR_TYPE_SYMBOL:
 334       if( !DEBUG_GetSymbolValue(exp->un.symbol.name, -1, &rtn, FALSE) )
 335         {
 336            RaiseException(DEBUG_STATUS_NO_SYMBOL, 0, 0, NULL);
 337         }
 338       break;
 339     case EXPR_TYPE_PSTRUCT:
 340       exp1 =  DEBUG_EvalExpr(exp->un.structure.exp1);
 341       if( exp1.type == NULL )
 342         {
 343           break;
 344         }
 345       rtn.off = DEBUG_TypeDerefPointer(&exp1, &type1);
 346       if( type1 == NULL )
 347         {
 348           break;
 349         }
 350       rtn.type = type1;
 351       DEBUG_FindStructElement(&rtn, exp->un.structure.element_name,
 352                               &exp->un.structure.result);
 353       break;
 354     case EXPR_TYPE_STRUCT:
 355       exp1 =  DEBUG_EvalExpr(exp->un.structure.exp1);
 356       if( exp1.type == NULL )
 357         {
 358           break;
 359         }
 360       rtn = exp1;
 361       DEBUG_FindStructElement(&rtn, exp->un.structure.element_name,
 362                               &exp->un.structure.result);
 363       break;
 364     case EXPR_TYPE_CALL:
 365       /*
 366        * First, evaluate all of the arguments.  If any of them are not
 367        * evaluable, then bail.
 368        */
 369       for(i=0; i < exp->un.call.nargs; i++)
 370         {
 371           exp1  = DEBUG_EvalExpr(exp->un.call.arg[i]);
 372           if( exp1.type == NULL )
 373             {
 374               return rtn;
 375             }
 376           cexp[i] = DEBUG_GetExprValue(&exp1, NULL);
 377         }
 378
 379       /*
 380        * Now look up the address of the function itself.
 381        */
 382       if( !DEBUG_GetSymbolValue(exp->un.call.funcname, -1, &rtn, FALSE ) )
 383         {
 384           fprintf(stderr, "Failed to find symbol\n");
 385           break;
 386         }
 387
 388 #if 0
 389       /* FIXME: NEWDBG NIY */
 390       /* Anyway, I wonder how this could work depending on the calling order of
 391        * the function (cdecl vs pascal for example)
 392        */
 393       int               (*fptr)();
 394
 395       fptr = (int (*)()) rtn.off;
 396       switch(exp->un.call.nargs)
 397         {
 398         case 0:
 399           exp->un.call.result = (*fptr)();
 400           break;
 401         case 1:
 402           exp->un.call.result = (*fptr)(cexp[0]);
 403           break;
 404         case 2:
 405           exp->un.call.result = (*fptr)(cexp[0], cexp[1]);
 406           break;
 407         case 3:
 408           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2]);
 409           break;
 410         case 4:
 411           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2], cexp[3]);
 412           break;
 413         case 5:
 414           exp->un.call.result = (*fptr)(cexp[0], cexp[1], cexp[2], cexp[3], cexp[4]);
 415           break;
 416         }
 417 #else
 418       fprintf(stderr, "Function call no longer implemented\n");
 419       /* would need to set up a call to this function, and then restore the current
 420        * context afterwards...
 421        */
 422       exp->un.call.result = 0;
 423 #endif
 424       rtn.type = DEBUG_TypeInt;
 425       rtn.off = (unsigned int) &exp->un.call.result;
 426
 427       break;
 428     case EXPR_TYPE_REGISTER:
 429       rtn.type = DEBUG_TypeIntConst;
 430       exp->un.rgister.result = DEBUG_GetRegister(exp->un.rgister.reg);
 431       rtn.off = (unsigned int) &exp->un.rgister.result;
 432 #ifdef __i386__
 433       if( exp->un.rgister.reg == REG_EIP )
 434           rtn.seg = DEBUG_context.SegCs;
 435       else
 436           rtn.seg = DEBUG_context.SegDs;
 437 #endif
 438       DEBUG_FixAddress( &rtn, 0 );
 439       break;
 440     case EXPR_TYPE_BINOP:
 441       exp1 = DEBUG_EvalExpr(exp->un.binop.exp1);
 442       exp2 = DEBUG_EvalExpr(exp->un.binop.exp2);
 443       if( exp1.type == NULL || exp2.type == NULL )
 444         {
 445           break;
 446         }
 447       if( exp1.type == DEBUG_TypeIntConst && exp2.type == DEBUG_TypeIntConst )
 448         {
 449           rtn.type = exp1.type;
 450         }
 451       else
 452         {
 453           rtn.type = DEBUG_TypeInt;
 454         }
 455       rtn.off = (unsigned int) &exp->un.binop.result;
 456       switch(exp->un.binop.binop_type)
 457         {
 458         case EXP_OP_ADD:
 459           type1 = DEBUG_GetPointerType(exp1.type);
 460           type2 = DEBUG_GetPointerType(exp2.type);
 461           scale1 = 1;
 462           scale2 = 1;
 463           if( type1 != NULL && type2 != NULL )
 464             {
 465               break;
 466             }
 467           else if( type1 != NULL )
 468             {
 469               scale2 = DEBUG_GetObjectSize(type1);
 470               rtn.type = exp1.type;
 471             }
 472           else if( type2 != NULL )
 473             {
 474               scale1 = DEBUG_GetObjectSize(type2);
 475               rtn.type = exp2.type;
 476             }
 477           rtn.seg = 0;
 478           exp->un.binop.result = (VAL(exp1) * scale1  + scale2 * VAL(exp2));
 479           break;
 480         case EXP_OP_SUB:
 481           type1 = DEBUG_GetPointerType(exp1.type);
 482           type2 = DEBUG_GetPointerType(exp2.type);
 483           scale1 = 1;
 484           scale2 = 1;
 485           scale3 = 1;
 486           if( type1 != NULL && type2 != NULL )
 487             {
 488               if( type1 != type2 )
 489                 {
 490                   break;
 491                 }
 492               scale3 = DEBUG_GetObjectSize(type1);
 493             }
 494           else if( type1 != NULL )
 495             {
 496               scale2 = DEBUG_GetObjectSize(type1);
 497               rtn.type = exp1.type;
 498             }
 499
 500           else if( type2 != NULL )
 501             {
 502               scale1 = DEBUG_GetObjectSize(type2);
 503               rtn.type = exp2.type;
 504             }
 505           rtn.seg = 0;
 506           exp->un.binop.result = (VAL(exp1) - VAL(exp2)) / scale3;
 507           break;
 508         case EXP_OP_SEG:
 509           rtn.seg = VAL(exp1);
 510           exp->un.binop.result = VAL(exp2);
 511 #ifdef __i386__
 512           DEBUG_FixSegment(&rtn);
 513 #endif
 514           break;
 515         case EXP_OP_LOR:
 516           rtn.seg = 0;
 517           exp->un.binop.result = (VAL(exp1) || VAL(exp2));
 518           break;
 519         case EXP_OP_LAND:
 520           rtn.seg = 0;
 521           exp->un.binop.result = (VAL(exp1) && VAL(exp2));
 522           break;
 523         case EXP_OP_OR:
 524           rtn.seg = 0;
 525           exp->un.binop.result = (VAL(exp1) | VAL(exp2));
 526           break;
 527         case EXP_OP_AND:
 528           rtn.seg = 0;
 529           exp->un.binop.result = (VAL(exp1) & VAL(exp2));
 530           break;
 531         case EXP_OP_XOR:
 532           rtn.seg = 0;
 533           exp->un.binop.result = (VAL(exp1) ^ VAL(exp2));
 534           break;
 535         case EXP_OP_EQ:
 536           rtn.seg = 0;
 537           exp->un.binop.result = (VAL(exp1) == VAL(exp2));
 538           break;
 539         case EXP_OP_GT:
 540           rtn.seg = 0;
 541           exp->un.binop.result = (VAL(exp1) > VAL(exp2));
 542           break;
 543         case EXP_OP_LT:
 544           rtn.seg = 0;
 545           exp->un.binop.result = (VAL(exp1) < VAL(exp2));
 546           break;
 547         case EXP_OP_GE:
 548           rtn.seg = 0;
 549           exp->un.binop.result = (VAL(exp1) >= VAL(exp2));
 550           break;
 551         case EXP_OP_LE:
 552           rtn.seg = 0;
 553           exp->un.binop.result = (VAL(exp1) <= VAL(exp2));
 554           break;
 555         case EXP_OP_NE:
 556           rtn.seg = 0;
 557           exp->un.binop.result = (VAL(exp1) != VAL(exp2));
 558           break;
 559         case EXP_OP_SHL:
 560           rtn.seg = 0;
 561           exp->un.binop.result = ((unsigned) VAL(exp1) << VAL(exp2));
 562           break;
 563         case EXP_OP_SHR:
 564           rtn.seg = 0;
 565           exp->un.binop.result = ((unsigned) VAL(exp1) >> VAL(exp2));
 566           break;
 567         case EXP_OP_MUL:
 568           rtn.seg = 0;
 569           exp->un.binop.result = (VAL(exp1) * VAL(exp2));
 570           break;
 571         case EXP_OP_DIV:
 572           if( VAL(exp2) != 0 )
 573             {
 574               rtn.seg = 0;
 575               exp->un.binop.result = (VAL(exp1) / VAL(exp2));
 576             }
 577           else
 578             {
 579               rtn.seg = 0;
 580               rtn.type = NULL;
 581               rtn.off = 0;
 582             }
 583           break;
 584         case EXP_OP_REM:
 585           if( VAL(exp2) != 0 )
 586             {
 587               rtn.seg = 0;
 588               exp->un.binop.result = (VAL(exp1) % VAL(exp2));
 589             }
 590           else
 591             {
 592               rtn.seg = 0;
 593               rtn.type = NULL;
 594               rtn.off = 0;
 595             }
 596           break;
 597         case EXP_OP_ARR:
 598           DEBUG_ArrayIndex(&exp1, &rtn, VAL(exp2));
 599           break;
 600         default:
 601           break;
 602         }
 603       break;
 604     case EXPR_TYPE_UNOP:
 605       exp1 = DEBUG_EvalExpr(exp->un.unop.exp1);
 606       if( exp1.type == NULL )
 607         {
 608           break;
 609         }
 610       rtn.off = (unsigned int) &exp->un.unop.result;
 611       if( exp1.type == DEBUG_TypeIntConst )
 612         {
 613           rtn.type = exp1.type;
 614         }
 615       else
 616         {
 617           rtn.type = DEBUG_TypeInt;
 618         }
 619       switch(exp->un.unop.unop_type)
 620         {
 621         case EXP_OP_NEG:
 622           rtn.seg = 0;
 623           exp->un.unop.result = -VAL(exp1);
 624           break;
 625         case EXP_OP_NOT:
 626           rtn.seg = 0;
 627           exp->un.unop.result = !VAL(exp1);
 628           break;
 629         case EXP_OP_LNOT:
 630           rtn.seg = 0;
 631           exp->un.unop.result = ~VAL(exp1);
 632           break;
 633         case EXP_OP_DEREF:
 634           rtn.seg = 0;
 635           rtn.off = (unsigned int) DEBUG_TypeDerefPointer(&exp1, &rtn.type);
 636           break;
 637         case EXP_OP_FORCE_DEREF:
 638           rtn.seg = exp1.seg;
 639           rtn.off = DEBUG_READ_MEM((void*)exp1.off, &rtn.off, sizeof(rtn.off));
 640           break;
 641         case EXP_OP_ADDR:
 642           rtn.seg = 0;
 643           rtn.type = DEBUG_FindOrMakePointerType(exp1.type);
 644           exp->un.unop.result = exp1.off;
 645           break;
 646         }
 647       break;
 648     default:
 649       fprintf(stderr,"Unexpected expression.\n");
 650       DEBUG_Exit(123);
 651       break;
 652     }
 653
 654   return rtn;
 655 }
 656
 657
 658 int
 659 DEBUG_DisplayExpr(struct expr * exp)
 660 {
 661   int           i;
 662
 663
 664   switch(exp->type)
 665     {
 666     case EXPR_TYPE_CAST:
 667       fprintf(stderr, "((");
 668       DEBUG_PrintTypeCast(exp->un.cast.cast);
 669       fprintf(stderr, ")");
 670       DEBUG_DisplayExpr(exp->un.cast.expr);
 671       fprintf(stderr, ")");
 672       break;
 673     case EXPR_TYPE_REGISTER:
 674       DEBUG_PrintRegister(exp->un.rgister.reg);
 675       break;
 676     case EXPR_TYPE_US_CONST:
 677       fprintf(stderr, "%ud", exp->un.u_const.value);
 678       break;
 679     case EXPR_TYPE_CONST:
 680       fprintf(stderr, "%d", exp->un.u_const.value);
 681       break;
 682     case EXPR_TYPE_STRING:
 683       fprintf(stderr, "\"%s\"", exp->un.string.str);
 684       break;
 685     case EXPR_TYPE_SYMBOL:
 686       fprintf(stderr, "%s" , exp->un.symbol.name);
 687       break;
 688     case EXPR_TYPE_PSTRUCT:
 689       DEBUG_DisplayExpr(exp->un.structure.exp1);
 690       fprintf(stderr, "->%s", exp->un.structure.element_name);
 691       break;
 692     case EXPR_TYPE_STRUCT:
 693       DEBUG_DisplayExpr(exp->un.structure.exp1);
 694       fprintf(stderr, ".%s", exp->un.structure.element_name);
 695       break;
 696     case EXPR_TYPE_CALL:
 697       fprintf(stderr, "%s(",exp->un.call.funcname);
 698       for(i=0; i < exp->un.call.nargs; i++)
 699         {
 700           DEBUG_DisplayExpr(exp->un.call.arg[i]);
 701           if( i != exp->un.call.nargs - 1 )
 702             {
 703               fprintf(stderr, ", ");
 704             }
 705         }
 706       fprintf(stderr, ")");
 707       break;
 708     case EXPR_TYPE_BINOP:
 709       fprintf(stderr, "( ");
 710       DEBUG_DisplayExpr(exp->un.binop.exp1);
 711       switch(exp->un.binop.binop_type)
 712         {
 713         case EXP_OP_ADD:
 714           fprintf(stderr, " + ");
 715           break;
 716         case EXP_OP_SUB:
 717           fprintf(stderr, " - ");
 718           break;
 719         case EXP_OP_SEG:
 720           fprintf(stderr, ":");
 721           break;
 722         case EXP_OP_LOR:
 723           fprintf(stderr, " || ");
 724           break;
 725         case EXP_OP_LAND:
 726           fprintf(stderr, " && ");
 727           break;
 728         case EXP_OP_OR:
 729           fprintf(stderr, " | ");
 730           break;
 731         case EXP_OP_AND:
 732           fprintf(stderr, " & ");
 733           break;
 734         case EXP_OP_XOR:
 735           fprintf(stderr, " ^ ");
 736           break;
 737         case EXP_OP_EQ:
 738           fprintf(stderr, " == ");
 739           break;
 740         case EXP_OP_GT:
 741           fprintf(stderr, " > ");
 742           break;
 743         case EXP_OP_LT:
 744           fprintf(stderr, " < ");
 745           break;
 746         case EXP_OP_GE:
 747           fprintf(stderr, " >= ");
 748           break;
 749         case EXP_OP_LE:
 750           fprintf(stderr, " <= ");
 751           break;
 752         case EXP_OP_NE:
 753           fprintf(stderr, " != ");
 754           break;
 755         case EXP_OP_SHL:
 756           fprintf(stderr, " << ");
 757           break;
 758         case EXP_OP_SHR:
 759           fprintf(stderr, " >> ");
 760           break;
 761         case EXP_OP_MUL:
 762           fprintf(stderr, " * ");
 763           break;
 764         case EXP_OP_DIV:
 765           fprintf(stderr, " / ");
 766           break;
 767         case EXP_OP_REM:
 768           fprintf(stderr, " %% ");
 769           break;
 770         case EXP_OP_ARR:
 771           fprintf(stderr, "[");
 772           break;
 773         default:
 774           break;
 775         }
 776       DEBUG_DisplayExpr(exp->un.binop.exp2);
 777       if( exp->un.binop.binop_type == EXP_OP_ARR )
 778         {
 779           fprintf(stderr, "]");
 780         }
 781       fprintf(stderr, " )");
 782       break;
 783     case EXPR_TYPE_UNOP:
 784       switch(exp->un.unop.unop_type)
 785         {
 786         case EXP_OP_NEG:
 787           fprintf(stderr, "-");
 788           break;
 789         case EXP_OP_NOT:
 790           fprintf(stderr, "!");
 791           break;
 792         case EXP_OP_LNOT:
 793           fprintf(stderr, "~");
 794           break;
 795         case EXP_OP_DEREF:
 796           fprintf(stderr, "*");
 797           break;
 798         case EXP_OP_ADDR:
 799           fprintf(stderr, "&");
 800           break;
 801         }
 802       DEBUG_DisplayExpr(exp->un.unop.exp1);
 803       break;
 804     default:
 805       fprintf(stderr,"Unexpected expression.\n");
 806       DEBUG_Exit(123);
 807       break;
 808     }
 809
 810   return TRUE;
 811 }
 812
 813 struct expr *
 814 DEBUG_CloneExpr(struct expr * exp)
 815 {
 816   int           i;
 817   struct expr * rtn;
 818
 819   rtn = (struct expr *) DBG_alloc(sizeof(struct expr));
 820
 821   /*
 822    * First copy the contents of the expression itself.
 823    */
 824   *rtn = *exp;
 825
 826
 827   switch(exp->type)
 828     {
 829     case EXPR_TYPE_CAST:
 830       rtn->un.cast.expr = DEBUG_CloneExpr(exp->un.cast.expr);
 831       break;
 832     case EXPR_TYPE_REGISTER:
 833     case EXPR_TYPE_US_CONST:
 834     case EXPR_TYPE_CONST:
 835       break;
 836     case EXPR_TYPE_STRING:
 837       rtn->un.string.str = DBG_strdup(exp->un.string.str);
 838       break;
 839     case EXPR_TYPE_SYMBOL:
 840       rtn->un.symbol.name = DBG_strdup(exp->un.symbol.name);
 841       break;
 842     case EXPR_TYPE_PSTRUCT:
 843     case EXPR_TYPE_STRUCT:
 844       rtn->un.structure.exp1 = DEBUG_CloneExpr(exp->un.structure.exp1);
 845       rtn->un.structure.element_name = DBG_strdup(exp->un.structure.element_name);
 846       break;
 847     case EXPR_TYPE_CALL:
 848       for(i=0; i < exp->un.call.nargs; i++)
 849         {
 850           rtn->un.call.arg[i]  = DEBUG_CloneExpr(exp->un.call.arg[i]);
 851         }
 852       rtn->un.call.funcname = DBG_strdup(exp->un.call.funcname);
 853       break;
 854     case EXPR_TYPE_BINOP:
 855       rtn->un.binop.exp1 = DEBUG_CloneExpr(exp->un.binop.exp1);
 856       rtn->un.binop.exp2 = DEBUG_CloneExpr(exp->un.binop.exp2);
 857       break;
 858     case EXPR_TYPE_UNOP:
 859       rtn->un.unop.exp1 = DEBUG_CloneExpr(exp->un.unop.exp1);
 860       break;
 861     default:
 862       fprintf(stderr,"Unexpected expression.\n");
 863       DEBUG_Exit(123);
 864       break;
 865     }
 866
 867   return rtn;
 868 }
 869
 870
 871 /*
 872  * Recursively go through an expression tree and free all memory associated
 873  * with it.
 874  */
 875 int
 876 DEBUG_FreeExpr(struct expr * exp)
 877 {
 878   int i;
 879
 880   switch(exp->type)
 881     {
 882     case EXPR_TYPE_CAST:
 883       DEBUG_FreeExpr(exp->un.cast.expr);
 884       break;
 885     case EXPR_TYPE_REGISTER:
 886     case EXPR_TYPE_US_CONST:
 887     case EXPR_TYPE_CONST:
 888       break;
 889     case EXPR_TYPE_STRING:
 890       DBG_free((char *) exp->un.string.str);
 891       break;
 892     case EXPR_TYPE_SYMBOL:
 893       DBG_free((char *) exp->un.symbol.name);
 894       break;
 895     case EXPR_TYPE_PSTRUCT:
 896     case EXPR_TYPE_STRUCT:
 897       DEBUG_FreeExpr(exp->un.structure.exp1);
 898       DBG_free((char *) exp->un.structure.element_name);
 899       break;
 900     case EXPR_TYPE_CALL:
 901       for(i=0; i < exp->un.call.nargs; i++)
 902         {
 903           DEBUG_FreeExpr(exp->un.call.arg[i]);
 904         }
 905       DBG_free((char *) exp->un.call.funcname);
 906       break;
 907     case EXPR_TYPE_BINOP:
 908       DEBUG_FreeExpr(exp->un.binop.exp1);
 909       DEBUG_FreeExpr(exp->un.binop.exp2);
 910       break;
 911     case EXPR_TYPE_UNOP:
 912       DEBUG_FreeExpr(exp->un.unop.exp1);
 913       break;
 914     default:
 915       fprintf(stderr,"Unexpected expression.\n");
 916       DEBUG_Exit(123);
 917       break;
 918     }
 919
 920   DBG_free(exp);
 921   return TRUE;
 922 }