smatch_helper.c

   1 /*
   2  * sparse/smatch_helper.c
   3  *
   4  * Copyright (C) 2006 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * Miscellaneous helper functions.
  12  */
  13
  14 #include <stdlib.h>
  15 #include <stdio.h>
  16 #include "allocate.h"
  17 #include "smatch.h"
  18
  19 #define VAR_LEN 512
  20
  21 char *alloc_string(const char *str)
  22 {
  23         char *tmp;
  24
  25         if (!str)
  26                 return NULL;
  27         tmp = malloc(strlen(str) + 1);
  28         strcpy(tmp, str);
  29         return tmp;
  30 }
  31
  32 void free_string(char *str)
  33 {
  34         free(str);
  35 }
  36
  37 void remove_parens(char *str)
  38 {
  39         char *src, *dst;
  40
  41         dst = src = str;
  42         while (*src != '\0') {
  43                 if (*src == '(' || *src == ')') {
  44                         src++;
  45                         continue;
  46                 }
  47                 *dst++ = *src++;
  48         }
  49         *dst = *src;
  50 }
  51
  52 struct smatch_state *alloc_state_num(int num)
  53 {
  54         struct smatch_state *state;
  55         static char buff[256];
  56
  57         state = __alloc_smatch_state(0);
  58         snprintf(buff, 255, "%d", num);
  59         buff[255] = '\0';
  60         state->name = alloc_string(buff);
  61         state->data = INT_PTR(num);
  62         return state;
  63 }
  64
  65 void append(char *dest, const char *data, int buff_len)
  66 {
  67         strncat(dest, data, buff_len - strlen(dest) - 1);
  68 }
  69
  70 /*
  71  * If you have "foo(a, b, 1);" then use
  72  * get_argument_from_call_expr(expr, 0) to return the expression for
  73  * a.  Yes, it does start counting from 0.
  74  */
  75 struct expression *get_argument_from_call_expr(struct expression_list *args,
  76                                                int num)
  77 {
  78         struct expression *expr;
  79         int i = 0;
  80
  81         if (!args)
  82                 return NULL;
  83
  84         FOR_EACH_PTR(args, expr) {
  85                 if (i == num)
  86                         return expr;
  87                 i++;
  88         } END_FOR_EACH_PTR(expr);
  89         return NULL;
  90 }
  91
  92 static struct expression *get_array_expr(struct expression *expr)
  93 {
  94         struct symbol *type;
  95
  96         if (expr->type != EXPR_BINOP || expr->op != '+')
  97                 return NULL;
  98
  99         type = get_type(expr->left);
 100         if (!type || type->type != SYM_ARRAY)
 101                 return NULL;
 102         return expr->left;
 103 }
 104
 105 static void __get_variable_from_expr(struct symbol **sym_ptr, char *buf,
 106                                      struct expression *expr, int len,
 107                                      int *complicated, int no_parens)
 108 {
 109         struct expression *tmp;
 110
 111         switch (expr->type) {
 112         case EXPR_DEREF:
 113                 tmp = expr->deref;
 114                 if (tmp->op == '*')
 115                         tmp = tmp->unop;
 116
 117                 __get_variable_from_expr(sym_ptr, buf, tmp, len, complicated, no_parens);
 118
 119                 tmp = expr->deref;
 120                 if (tmp->op == '*')
 121                         append(buf, "->", len);
 122                 else
 123                         append(buf, ".", len);
 124
 125                 if (expr->member && expr->member->name)
 126                         append(buf, expr->member->name, len);
 127                 else
 128                         append(buf, "unknown_member", len);
 129
 130                 return;
 131         case EXPR_SYMBOL:
 132                 if (expr->symbol_name)
 133                         append(buf, expr->symbol_name->name, len);
 134                 if (sym_ptr) {
 135                         if (*sym_ptr)
 136                                 *complicated = 1;
 137                         *sym_ptr = expr->symbol;
 138                 }
 139                 return;
 140         case EXPR_PREOP: {
 141                 const char *tmp;
 142
 143                 if (get_expression_statement(expr)) {
 144                         *complicated = 2;
 145                         return;
 146                 }
 147
 148                 if (expr->op == '(') {
 149                         if (!no_parens)
 150                                 append(buf, "(", len);
 151                 } else if (expr->op != '*' || !get_array_expr(expr->unop)) {
 152                         tmp = show_special(expr->op);
 153                         append(buf, tmp, len);
 154                 }
 155                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 156                                                  len, complicated, no_parens);
 157
 158                 if (expr->op == '(' && !no_parens)
 159                         append(buf, ")", len);
 160
 161                 if (expr->op == SPECIAL_DECREMENT ||
 162                                 expr->op == SPECIAL_INCREMENT)
 163                         *complicated = 1;
 164
 165                 return;
 166         }
 167         case EXPR_POSTOP: {
 168                 const char *tmp;
 169
 170                 __get_variable_from_expr(sym_ptr, buf, expr->unop,
 171                                                  len, complicated, no_parens);
 172                 tmp = show_special(expr->op);
 173                 append(buf, tmp, len);
 174
 175                 if (expr->op == SPECIAL_DECREMENT || expr->op == SPECIAL_INCREMENT)
 176                         *complicated = 1;
 177                 return;
 178         }
 179         case EXPR_ASSIGNMENT:
 180         case EXPR_COMPARE:
 181         case EXPR_LOGICAL:
 182         case EXPR_BINOP: {
 183                 char tmp[10];
 184                 struct expression *array_expr;
 185
 186                 *complicated = 1;
 187                 array_expr = get_array_expr(expr);
 188                 if (array_expr) {
 189                         __get_variable_from_expr(sym_ptr, buf, array_expr, len, complicated, no_parens);
 190                         append(buf, "[", len);
 191                 } else {
 192                         __get_variable_from_expr(sym_ptr, buf, expr->left, len, complicated, no_parens);
 193                         snprintf(tmp, sizeof(tmp), " %s ", show_special(expr->op));
 194                         append(buf, tmp, len);
 195                 }
 196                 __get_variable_from_expr(NULL, buf, expr->right, len, complicated, no_parens);
 197                 if (array_expr)
 198                         append(buf, "]", len);
 199                 return;
 200         }
 201         case EXPR_VALUE: {
 202                 char tmp[25];
 203
 204                 *complicated = 1;
 205                 snprintf(tmp, 25, "%lld", expr->value);
 206                 append(buf, tmp, len);
 207                 return;
 208         }
 209         case EXPR_STRING:
 210                 append(buf, "\"", len);
 211                 append(buf, expr->string->data, len);
 212                 append(buf, "\"", len);
 213                 return;
 214         case EXPR_CALL: {
 215                 struct expression *tmp;
 216                 int i;
 217
 218                 *complicated = 1;
 219                 __get_variable_from_expr(NULL, buf, expr->fn, len, complicated, no_parens);
 220                 append(buf, "(", len);
 221                 i = 0;
 222                 FOR_EACH_PTR(expr->args, tmp) {
 223                         if (i++)
 224                                 append(buf, ", ", len);
 225                         __get_variable_from_expr(NULL, buf, tmp, len, complicated, no_parens);
 226                 } END_FOR_EACH_PTR(tmp);
 227                 append(buf, ")", len);
 228                 return;
 229         }
 230         case EXPR_CAST:
 231                 __get_variable_from_expr(sym_ptr, buf,
 232                                          expr->cast_expression, len,
 233                                          complicated, no_parens);
 234                 return;
 235         case EXPR_SIZEOF: {
 236                 int size;
 237                 char tmp[25];
 238
 239                 if (expr->cast_type && get_base_type(expr->cast_type)) {
 240                         size = (get_base_type(expr->cast_type))->bit_size;
 241                         snprintf(tmp, 25, "%d", bits_to_bytes(size));
 242                         append(buf, tmp, len);
 243                 }
 244                 return;
 245         }
 246         case EXPR_IDENTIFIER:
 247                 *complicated = 1;
 248                 if (expr->expr_ident && expr->expr_ident->name)
 249                         append(buf, expr->expr_ident->name, len);
 250                 return;
 251         default:
 252                 *complicated = 1;
 253                 //printf("unknown type = %d\n", expr->type);
 254                 return;
 255         }
 256 }
 257
 258 /*
 259  * This is returns a stylized "c looking" representation of the
 260  * variable name.
 261  *
 262  * It uses the same buffer every time so you have to save the result
 263  * yourself if you want to keep it.
 264  *
 265  */
 266
 267 char *expr_to_str_sym(struct expression *expr, struct symbol **sym_ptr)
 268 {
 269         static char var_name[VAR_LEN];
 270         int complicated = 0;
 271
 272         if (sym_ptr)
 273                 *sym_ptr = NULL;
 274         var_name[0] = '\0';
 275
 276         if (!expr)
 277                 return NULL;
 278         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 279                                  &complicated, 0);
 280         if (complicated < 2)
 281                 return alloc_string(var_name);
 282         else
 283                 return NULL;
 284 }
 285
 286 char *expr_to_str(struct expression *expr)
 287 {
 288         return expr_to_str_sym(expr, NULL);
 289 }
 290
 291 /*
 292  * get_variable_from_expr_simple() only returns simple variables.
 293  * If it's a complicated variable like a->foo[x] instead of just 'a->foo'
 294  * then it returns NULL.
 295  */
 296 char *expr_to_var_sym(struct expression *expr,
 297                                     struct symbol **sym_ptr)
 298 {
 299         static char var_name[VAR_LEN];
 300         int complicated = 0;
 301
 302         if (sym_ptr)
 303                 *sym_ptr = NULL;
 304         var_name[0] = '\0';
 305
 306         if (!expr)
 307                 return NULL;
 308         expr = strip_expr(expr);
 309         __get_variable_from_expr(sym_ptr, var_name, expr, sizeof(var_name),
 310                                  &complicated, 1);
 311
 312         if (complicated) {
 313                 if (sym_ptr)
 314                         *sym_ptr = NULL;
 315                 return NULL;
 316         }
 317         return alloc_string(var_name);
 318 }
 319
 320 char *expr_to_var(struct expression *expr)
 321 {
 322         return expr_to_var_sym(expr, NULL);
 323 }
 324
 325 int sym_name_is(const char *name, struct expression *expr)
 326 {
 327         if (!expr)
 328                 return 0;
 329         if (expr->type != EXPR_SYMBOL)
 330                 return 0;
 331         if (!strcmp(expr->symbol_name->name, name))
 332                 return 1;
 333         return 0;
 334 }
 335
 336 int is_zero(struct expression *expr)
 337 {
 338         sval_t sval;
 339
 340         if (get_value(expr, &sval) && sval.value == 0)
 341                 return 1;
 342         return 0;
 343 }
 344
 345 int is_array(struct expression *expr)
 346 {
 347         expr = strip_expr(expr);
 348         if (!expr || expr->type != EXPR_PREOP || expr->op != '*')
 349                 return 0;
 350         expr = expr->unop;
 351         if (expr->op != '+')
 352                 return 0;
 353         return 1;
 354 }
 355
 356 struct expression *get_array_name(struct expression *expr)
 357 {
 358         if (!is_array(expr))
 359                 return NULL;
 360         return strip_expr(expr->unop->left);
 361 }
 362
 363 struct expression *get_array_offset(struct expression *expr)
 364 {
 365         if (!is_array(expr))
 366                 return NULL;
 367         return expr->unop->right;
 368 }
 369
 370 const char *show_state(struct smatch_state *state)
 371 {
 372         if (!state)
 373                 return NULL;
 374         return state->name;
 375 }
 376
 377 struct statement *get_expression_statement(struct expression *expr)
 378 {
 379         /* What are those things called? if (({....; ret;})) { ...*/
 380
 381         if (expr->type != EXPR_PREOP)
 382                 return NULL;
 383         if (expr->op != '(')
 384                 return NULL;
 385         if (expr->unop->type != EXPR_STATEMENT)
 386                 return NULL;
 387         if (expr->unop->statement->type != STMT_COMPOUND)
 388                 return NULL;
 389         return expr->unop->statement;
 390 }
 391
 392 struct expression *strip_parens(struct expression *expr)
 393 {
 394         if (!expr)
 395                 return NULL;
 396
 397         if (expr->type == EXPR_PREOP) {
 398                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 399                         expr->unop->statement->type == STMT_COMPOUND)
 400                         return expr;
 401                 if (expr->op == '(')
 402                         return strip_parens(expr->unop);
 403         }
 404         return expr;
 405 }
 406
 407 struct expression *strip_expr(struct expression *expr)
 408 {
 409         if (!expr)
 410                 return NULL;
 411
 412         switch (expr->type) {
 413         case EXPR_FORCE_CAST:
 414         case EXPR_CAST:
 415                 return strip_expr(expr->cast_expression);
 416         case EXPR_PREOP:
 417                 if (expr->op == '(' && expr->unop->type == EXPR_STATEMENT &&
 418                         expr->unop->statement->type == STMT_COMPOUND)
 419                         return expr;
 420                 if (expr->op == '(')
 421                         return strip_expr(expr->unop);
 422         }
 423         return expr;
 424 }
 425
 426 static void delete_state_tracker(struct tracker *t)
 427 {
 428         delete_state(t->owner, t->name, t->sym);
 429         __free_tracker(t);
 430 }
 431
 432 void scoped_state(int my_id, const char *name, struct symbol *sym)
 433 {
 434         struct tracker *t;
 435
 436         t = alloc_tracker(my_id, name, sym);
 437         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 438 }
 439
 440 int is_error_return(struct expression *expr)
 441 {
 442         struct symbol *cur_func = cur_func_sym;
 443         sval_t sval;
 444
 445         if (!expr)
 446                 return 0;
 447         if (cur_func->type != SYM_NODE)
 448                 return 0;
 449         cur_func = get_base_type(cur_func);
 450         if (cur_func->type != SYM_FN)
 451                 return 0;
 452         cur_func = get_base_type(cur_func);
 453         if (cur_func == &void_ctype)
 454                 return 0;
 455         if (!get_implied_value(expr, &sval))
 456                 return 0;
 457         if (sval.value < 0)
 458                 return 1;
 459         if (cur_func->type == SYM_PTR && sval.value == 0)
 460                 return 1;
 461         return 0;
 462 }
 463
 464 int getting_address(void)
 465 {
 466         struct expression *tmp;
 467         int i = 0;
 468         int dot_ops = 0;
 469
 470         FOR_EACH_PTR_REVERSE(big_expression_stack, tmp) {
 471                 if (!i++)
 472                         continue;
 473                 if (tmp->type == EXPR_PREOP && tmp->op == '(')
 474                         continue;
 475                 if (tmp->op == '.' && !dot_ops++)
 476                         continue;
 477                 if (tmp->op == '&')
 478                         return 1;
 479                 return 0;
 480         } END_FOR_EACH_PTR_REVERSE(tmp);
 481         return 0;
 482 }
 483
 484 char *get_member_name(struct expression *expr)
 485 {
 486         char buf[256];
 487         struct symbol *sym;
 488
 489         expr = strip_expr(expr);
 490         if (expr->type != EXPR_DEREF)
 491                 return NULL;
 492         sym = get_type(expr->deref);
 493         if (!sym)
 494                 return NULL;
 495         /* FIXME: HACK! Sparse isn't storing the names of unions...  Just take last member */
 496         if (sym->type == SYM_UNION) {
 497                 struct symbol *tmp;
 498
 499                 FOR_EACH_PTR_REVERSE(sym->symbol_list, tmp) {
 500                         if (tmp->ident) {
 501                                 const char *member_name;
 502
 503                                 if (expr->member)
 504                                         member_name = expr->member->name;
 505                                 else
 506                                         member_name = "unknown_member";
 507                                 snprintf(buf, sizeof(buf), "(union hack %s)->%s", tmp->ident->name, member_name);
 508                                 return alloc_string(buf);
 509                         }
 510                 } END_FOR_EACH_PTR_REVERSE(tmp);
 511                 return NULL;
 512         }
 513         if (!sym->ident || !expr->member)
 514                 return NULL;
 515         snprintf(buf, sizeof(buf), "(struct %s)->%s", sym->ident->name, expr->member->name);
 516         return alloc_string(buf);
 517 }
 518
 519 int positions_eq(struct position pos1, struct position pos2)
 520 {
 521         if (pos1.line != pos2.line)
 522                 return 0;
 523         if (pos1.pos != pos2.pos)
 524                 return 0;
 525         if (pos1.stream != pos2.stream)
 526                 return 0;
 527         return 1;
 528 }
 529
 530 struct statement *get_current_statement(void)
 531 {
 532         struct statement *prev, *tmp;
 533
 534         prev = last_ptr_list((struct ptr_list *)big_statement_stack);
 535
 536         if (!prev || !get_macro_name(prev->pos))
 537                 return prev;
 538
 539         FOR_EACH_PTR_REVERSE(big_statement_stack, tmp) {
 540                 if (positions_eq(tmp->pos, prev->pos))
 541                         continue;
 542                 if (prev->pos.line > tmp->pos.line)
 543                         return prev;
 544                 return tmp;
 545         } END_FOR_EACH_PTR_REVERSE(tmp);
 546         return prev;
 547 }
 548
 549 int get_param_num_from_sym(struct symbol *sym)
 550 {
 551         struct symbol *tmp;
 552         int i;
 553
 554         if (!cur_func_sym)
 555                 return -1;
 556
 557         i = 0;
 558         FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, tmp) {
 559                 if (tmp == sym)
 560                         return i;
 561                 i++;
 562         } END_FOR_EACH_PTR(tmp);
 563         return -1;
 564 }
 565
 566 int get_param_num(struct expression *expr)
 567 {
 568         struct symbol *sym;
 569         char *name;
 570
 571         if (!cur_func_sym)
 572                 return -1;
 573         name = expr_to_var_sym(expr, &sym);
 574         free_string(name);
 575         if (!sym)
 576                 return -1;
 577         return get_param_num_from_sym(sym);
 578 }
 579
 580 int ms_since(struct timeval *start)
 581 {
 582         struct timeval end;
 583         double diff;
 584
 585         gettimeofday(&end, NULL);
 586         diff = (end.tv_sec - start->tv_sec) * 1000.0;
 587         diff += (end.tv_usec - start->tv_usec) / 1000.0;
 588         return (int)diff;
 589 }
 590